Provided by: libguestfs-dev_1.24.5-1ubuntu0.1_amd64 
NAME
guestfs - Library for accessing and modifying virtual machine images
SYNOPSIS
#include <guestfs.h>
guestfs_h *g = guestfs_create ();
guestfs_add_drive (g, "guest.img");
guestfs_launch (g);
guestfs_mount (g, "/dev/sda1", "/");
guestfs_touch (g, "/hello");
guestfs_umount (g, "/");
guestfs_shutdown (g);
guestfs_close (g);
cc prog.c -o prog -lguestfs
or:
cc prog.c -o prog `pkg-config libguestfs --cflags --libs`
DESCRIPTION
Libguestfs is a library for accessing and modifying disk images and virtual machines. This manual page
documents the C API.
If you are looking for an introduction to libguestfs, see the web site: http://libguestfs.org/
Each virt tool has its own man page (for a full list, go to "SEE ALSO" at the end of this file).
The libguestfs FAQ contains many useful answers: guestfs-faq(1).
For examples of using the API from C, see guestfs-examples(3). For examples in other languages, see
"USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES" below.
For tips and recipes, see guestfs-recipes(1).
If you are having performance problems, read guestfs-performance(1). To help test libguestfs, read
libguestfs-test-tool(1) and guestfs-testing(1).
API OVERVIEW
This section provides a gentler overview of the libguestfs API. We also try to group API calls together,
where that may not be obvious from reading about the individual calls in the main section of this manual.
HANDLES
Before you can use libguestfs calls, you have to create a handle. Then you must add at least one disk
image to the handle, followed by launching the handle, then performing whatever operations you want, and
finally closing the handle. By convention we use the single letter "g" for the name of the handle
variable, although of course you can use any name you want.
The general structure of all libguestfs-using programs looks like this:
guestfs_h *g = guestfs_create ();
/* Call guestfs_add_drive additional times if there are
* multiple disk images.
*/
guestfs_add_drive (g, "guest.img");
/* Most manipulation calls won't work until you've launched
* the handle 'g'. You have to do this _after_ adding drives
* and _before_ other commands.
*/
guestfs_launch (g);
/* Either: examine what partitions, LVs etc are available: */
char **partitions = guestfs_list_partitions (g);
char **logvols = guestfs_lvs (g);
/* Or: ask libguestfs to find filesystems for you: */
char **filesystems = guestfs_list_filesystems (g);
/* Or: use inspection (see INSPECTION section below). */
/* To access a filesystem in the image, you must mount it. */
guestfs_mount (g, "/dev/sda1", "/");
/* Now you can perform filesystem actions on the guest
* disk image.
*/
guestfs_touch (g, "/hello");
/* Synchronize the disk. This is the opposite of guestfs_launch. */
guestfs_shutdown (g);
/* Close and free the handle 'g'. */
guestfs_close (g);
The code above doesn't include any error checking. In real code you should check return values carefully
for errors. In general all functions that return integers return "-1" on error, and all functions that
return pointers return "NULL" on error. See section "ERROR HANDLING" below for how to handle errors, and
consult the documentation for each function call below to see precisely how they return error
indications. See guestfs-examples(3) for fully worked examples.
DISK IMAGES
The image filename ("guest.img" in the example above) could be a disk image from a virtual machine, a
dd(1) copy of a physical hard disk, an actual block device, or simply an empty file of zeroes that you
have created through posix_fallocate(3). Libguestfs lets you do useful things to all of these.
The call you should use in modern code for adding drives is "guestfs_add_drive_opts". To add a disk
image, allowing writes, and specifying that the format is raw, do:
guestfs_add_drive_opts (g, filename,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
-1);
You can add a disk read-only using:
guestfs_add_drive_opts (g, filename,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
-1);
or by calling the older function "guestfs_add_drive_ro". If you use the readonly flag, libguestfs won't
modify the file. (See also "DISK IMAGE FORMATS" below).
Be extremely cautious if the disk image is in use, eg. if it is being used by a virtual machine. Adding
it read-write will almost certainly cause disk corruption, but adding it read-only is safe.
You should usually add at least one disk image, and you may add multiple disk images. If adding multiple
disk images, they usually have to be "related", ie. from the same guest. In the API, the disk images are
usually referred to as "/dev/sda" (for the first one you added), "/dev/sdb" (for the second one you
added), etc.
Once "guestfs_launch" has been called you cannot add any more images. You can call
"guestfs_list_devices" to get a list of the device names, in the order that you added them. See also
"BLOCK DEVICE NAMING" below.
There are slightly different rules when hotplugging disks (in libguestfs ≥ 1.20). See "HOTPLUGGING"
below.
MOUNTING
Before you can read or write files, create directories and so on in a disk image that contains
filesystems, you have to mount those filesystems using "guestfs_mount" or "guestfs_mount_ro". If you
already know that a disk image contains (for example) one partition with a filesystem on that partition,
then you can mount it directly:
guestfs_mount (g, "/dev/sda1", "/");
where "/dev/sda1" means literally the first partition (1) of the first disk image that we added
("/dev/sda"). If the disk contains Linux LVM2 logical volumes you could refer to those instead (eg.
"/dev/VG/LV"). Note that these are libguestfs virtual devices, and are nothing to do with host devices.
If you are given a disk image and you don't know what it contains then you have to find out. Libguestfs
can do that too: use "guestfs_list_partitions" and "guestfs_lvs" to list possible partitions and LVs, and
either try mounting each to see what is mountable, or else examine them with "guestfs_vfs_type" or
"guestfs_file". To list just filesystems, use "guestfs_list_filesystems".
Libguestfs also has a set of APIs for inspection of unknown disk images (see "INSPECTION" below). You
might also want to look at higher level programs built on top of libguestfs, in particular
virt-inspector(1).
To mount a filesystem read-only, use "guestfs_mount_ro". There are several other variations of the
"guestfs_mount_*" call.
FILESYSTEM ACCESS AND MODIFICATION
The majority of the libguestfs API consists of fairly low-level calls for accessing and modifying the
files, directories, symlinks etc on mounted filesystems. There are over a hundred such calls which you
can find listed in detail below in this man page, and we don't even pretend to cover them all in this
overview.
Specify filenames as full paths, starting with "/" and including the mount point.
For example, if you mounted a filesystem at "/" and you want to read the file called "etc/passwd" then
you could do:
char *data = guestfs_cat (g, "/etc/passwd");
This would return "data" as a newly allocated buffer containing the full content of that file (with some
conditions: see also "DOWNLOADING" below), or "NULL" if there was an error.
As another example, to create a top-level directory on that filesystem called "var" you would do:
guestfs_mkdir (g, "/var");
To create a symlink you could do:
guestfs_ln_s (g, "/etc/init.d/portmap",
"/etc/rc3.d/S30portmap");
Libguestfs will reject attempts to use relative paths and there is no concept of a current working
directory.
Libguestfs can return errors in many situations: for example if the filesystem isn't writable, or if a
file or directory that you requested doesn't exist. If you are using the C API (documented here) you
have to check for those error conditions after each call. (Other language bindings turn these errors
into exceptions).
File writes are affected by the per-handle umask, set by calling "guestfs_umask" and defaulting to 022.
See "UMASK".
Since libguestfs 1.18, it is possible to mount the libguestfs filesystem on a local directory, subject to
some restrictions. See "MOUNT LOCAL" below.
PARTITIONING
Libguestfs contains API calls to read, create and modify partition tables on disk images.
In the common case where you want to create a single partition covering the whole disk, you should use
the "guestfs_part_disk" call:
const char *parttype = "mbr";
if (disk_is_larger_than_2TB)
parttype = "gpt";
guestfs_part_disk (g, "/dev/sda", parttype);
Obviously this effectively wipes anything that was on that disk image before.
LVM2
Libguestfs provides access to a large part of the LVM2 API, such as "guestfs_lvcreate" and
"guestfs_vgremove". It won't make much sense unless you familiarize yourself with the concepts of
physical volumes, volume groups and logical volumes.
This author strongly recommends reading the LVM HOWTO, online at http://tldp.org/HOWTO/LVM-HOWTO/.
DOWNLOADING
Use "guestfs_cat" to download small, text only files. This call cannot handle files containing any ASCII
NUL ("\0") characters. However the API is very simple to use.
"guestfs_read_file" can be used to read files which contain arbitrary 8 bit data, since it returns a
(pointer, size) pair.
"guestfs_download" can be used to download any file, with no limits on content or size.
To download multiple files, see "guestfs_tar_out" and "guestfs_tgz_out".
UPLOADING
To write a small file with fixed content, use "guestfs_write". To create a file of all zeroes, use
"guestfs_truncate_size" (sparse) or "guestfs_fallocate64" (with all disk blocks allocated). There are a
variety of other functions for creating test files, for example "guestfs_fill" and
"guestfs_fill_pattern".
To upload a single file, use "guestfs_upload". This call has no limits on file content or size.
To upload multiple files, see "guestfs_tar_in" and "guestfs_tgz_in".
However the fastest way to upload large numbers of arbitrary files is to turn them into a squashfs or CD
ISO (see mksquashfs(8) and mkisofs(8)), then attach this using "guestfs_add_drive_ro". If you add the
drive in a predictable way (eg. adding it last after all other drives) then you can get the device name
from "guestfs_list_devices" and mount it directly using "guestfs_mount_ro". Note that squashfs images
are sometimes non-portable between kernel versions, and they don't support labels or UUIDs. If you want
to pre-build an image or you need to mount it using a label or UUID, use an ISO image instead.
COPYING
There are various different commands for copying between files and devices and in and out of the guest
filesystem. These are summarised in the table below.
file to file
Use "guestfs_cp" to copy a single file, or "guestfs_cp_a" to copy directories recursively.
To copy part of a file (offset and size) use "guestfs_copy_file_to_file".
file to device
device to file
device to device
Use "guestfs_copy_file_to_device", "guestfs_copy_device_to_file", or "guestfs_copy_device_to_device".
Example: duplicate the contents of an LV:
guestfs_copy_device_to_device (g,
"/dev/VG/Original", "/dev/VG/Copy",
/* -1 marks the end of the list of optional parameters */
-1);
The destination ("/dev/VG/Copy") must be at least as large as the source ("/dev/VG/Original"). To
copy less than the whole source device, use the optional "size" parameter:
guestfs_copy_device_to_device (g,
"/dev/VG/Original", "/dev/VG/Copy",
GUESTFS_COPY_DEVICE_TO_DEVICE_SIZE, 10000,
-1);
file on the host to file or device
Use "guestfs_upload". See "UPLOADING" above.
file or device to file on the host
Use "guestfs_download". See "DOWNLOADING" above.
UPLOADING AND DOWNLOADING TO PIPES AND FILE DESCRIPTORS
Calls like "guestfs_upload", "guestfs_download", "guestfs_tar_in", "guestfs_tar_out" etc appear to only
take filenames as arguments, so it appears you can only upload and download to files. However many
Un*x-like hosts let you use the special device files "/dev/stdin", "/dev/stdout", "/dev/stderr" and
"/dev/fd/N" to read and write from stdin, stdout, stderr, and arbitrary file descriptor N.
For example, virt-cat(1) writes its output to stdout by doing:
guestfs_download (g, filename, "/dev/stdout");
and you can write tar output to a file descriptor "fd" by doing:
char devfd[64];
snprintf (devfd, sizeof devfd, "/dev/fd/%d", fd);
guestfs_tar_out (g, "/", devfd);
LISTING FILES
"guestfs_ll" is just designed for humans to read (mainly when using the guestfish(1)-equivalent command
"ll").
"guestfs_ls" is a quick way to get a list of files in a directory from programs, as a flat list of
strings.
"guestfs_readdir" is a programmatic way to get a list of files in a directory, plus additional
information about each one. It is more equivalent to using the readdir(3) call on a local filesystem.
"guestfs_find" and "guestfs_find0" can be used to recursively list files.
RUNNING COMMANDS
Although libguestfs is primarily an API for manipulating files inside guest images, we also provide some
limited facilities for running commands inside guests.
There are many limitations to this:
• The kernel version that the command runs under will be different from what it expects.
• If the command needs to communicate with daemons, then most likely they won't be running.
• The command will be running in limited memory.
• The network may not be available unless you enable it (see "guestfs_set_network").
• Only supports Linux guests (not Windows, BSD, etc).
• Architecture limitations (eg. won't work for a PPC guest on an X86 host).
• For SELinux guests, you may need to enable SELinux and load policy first. See "SELINUX" in this
manpage.
• Security: It is not safe to run commands from untrusted, possibly malicious guests. These commands
may attempt to exploit your program by sending unexpected output. They could also try to exploit the
Linux kernel or qemu provided by the libguestfs appliance. They could use the network provided by
the libguestfs appliance to bypass ordinary network partitions and firewalls. They could use the
elevated privileges or different SELinux context of your program to their advantage.
A secure alternative is to use libguestfs to install a "firstboot" script (a script which runs when
the guest next boots normally), and to have this script run the commands you want in the normal
context of the running guest, network security and so on. For information about other security
issues, see "SECURITY".
The two main API calls to run commands are "guestfs_command" and "guestfs_sh" (there are also
variations).
The difference is that "guestfs_sh" runs commands using the shell, so any shell globs, redirections, etc
will work.
CONFIGURATION FILES
To read and write configuration files in Linux guest filesystems, we strongly recommend using Augeas.
For example, Augeas understands how to read and write, say, a Linux shadow password file or X.org
configuration file, and so avoids you having to write that code.
The main Augeas calls are bound through the "guestfs_aug_*" APIs. We don't document Augeas itself here
because there is excellent documentation on the http://augeas.net/ website.
If you don't want to use Augeas (you fool!) then try calling "guestfs_read_lines" to get the file as a
list of lines which you can iterate over.
SYSTEMD JOURNAL FILES
To read the systemd journal from a Linux guest, use the "guestfs_journal_*" APIs starting with
"guestfs_journal_open".
Consult the journal documentation here: sd-journal(3), sd_journal_open(3).
SELINUX
We support SELinux guests. To ensure that labeling happens correctly in SELinux guests, you need to
enable SELinux and load the guest's policy:
1. Before launching, do:
guestfs_set_selinux (g, 1);
2. After mounting the guest's filesystem(s), load the policy. This is best done by running the
load_policy(8) command in the guest itself:
guestfs_sh (g, "/usr/sbin/load_policy");
(Older versions of "load_policy" require you to specify the name of the policy file).
3. Optionally, set the security context for the API. The correct security context to use can only be
known by inspecting the guest. As an example:
guestfs_setcon (g, "unconfined_u:unconfined_r:unconfined_t:s0");
This will work for running commands and editing existing files.
When new files are created, you may need to label them explicitly, for example by running the external
command "restorecon pathname".
UMASK
Certain calls are affected by the current file mode creation mask (the "umask"). In particular ones
which create files or directories, such as "guestfs_touch", "guestfs_mknod" or "guestfs_mkdir". This
affects either the default mode that the file is created with or modifies the mode that you supply.
The default umask is 022, so files are created with modes such as 0644 and directories with 0755.
There are two ways to avoid being affected by umask. Either set umask to 0 (call "guestfs_umask (g, 0)"
early after launching). Or call "guestfs_chmod" after creating each file or directory.
For more information about umask, see umask(2).
LABELS AND UUIDS
Many filesystems, devices and logical volumes support either labels (short strings like "BOOT" which
might not be unique) and/or UUIDs (globally unique IDs).
For filesystems, use "guestfs_vfs_label" or "guestfs_vfs_uuid" to read the label or UUID. Some
filesystems let you call "guestfs_set_label" or "guestfs_set_uuid" to change the label or UUID.
You can locate a filesystem by its label or UUID using "guestfs_findfs_label" or "guestfs_findfs_uuid".
For LVM2 (which supports only UUIDs), there is a rich set of APIs for fetching UUIDs, fetching UUIDs of
the contained objects, and changing UUIDs. See: "guestfs_lvuuid", "guestfs_vguuid", "guestfs_pvuuid",
"guestfs_vglvuuids", "guestfs_vgpvuuids", "guestfs_vgchange_uuid", "guestfs_vgchange_uuid_all",
"guestfs_pvchange_uuid", "guestfs_pvchange_uuid_all".
Note when cloning a filesystem, device or whole guest, it is a good idea to set new randomly generated
UUIDs on the copy.
ENCRYPTED DISKS
Libguestfs allows you to access Linux guests which have been encrypted using whole disk encryption that
conforms to the Linux Unified Key Setup (LUKS) standard. This includes nearly all whole disk encryption
systems used by modern Linux guests.
Use "guestfs_vfs_type" to identify LUKS-encrypted block devices (it returns the string "crypto_LUKS").
Then open these devices by calling "guestfs_luks_open". Obviously you will require the passphrase!
Opening a LUKS device creates a new device mapper device called "/dev/mapper/mapname" (where "mapname" is
the string you supply to "guestfs_luks_open"). Reads and writes to this mapper device are decrypted from
and encrypted to the underlying block device respectively.
LVM volume groups on the device can be made visible by calling "guestfs_vgscan" followed by
"guestfs_vg_activate_all". The logical volume(s) can now be mounted in the usual way.
Use the reverse process to close a LUKS device. Unmount any logical volumes on it, deactivate the volume
groups by caling "guestfs_vg_activate (g, 0, ["/dev/VG"])". Then close the mapper device by calling
"guestfs_luks_close" on the "/dev/mapper/mapname" device (not the underlying encrypted block device).
MOUNT LOCAL
In libguestfs ≥ 1.18, it is possible to mount the libguestfs filesystem on a local directory and access
it using ordinary POSIX calls and programs.
Availability of this is subject to a number of restrictions: it requires FUSE (the Filesystem in
USErspace), and libfuse must also have been available when libguestfs was compiled. FUSE may require
that a kernel module is loaded, and it may be necessary to add the current user to a special "fuse"
group. See the documentation for your distribution and http://fuse.sf.net for further information.
The call to mount the libguestfs filesystem on a local directory is "guestfs_mount_local" (q.v.) followed
by "guestfs_mount_local_run". The latter does not return until you unmount the filesystem. The reason
is that the call enters the FUSE main loop and processes kernel requests, turning them into libguestfs
calls. An alternative design would have been to create a background thread to do this, but libguestfs
doesn't require pthreads. This way is also more flexible: for example the user can create another thread
for "guestfs_mount_local_run".
"guestfs_mount_local" needs a certain amount of time to set up the mountpoint. The mountpoint is not
ready to use until the call returns. At this point, accesses to the filesystem will block until the main
loop is entered (ie. "guestfs_mount_local_run"). So if you need to start another process to access the
filesystem, put the fork between "guestfs_mount_local" and "guestfs_mount_local_run".
MOUNT LOCAL COMPATIBILITY
Since local mounting was only added in libguestfs 1.18, and may not be available even in these builds,
you should consider writing code so that it doesn't depend on this feature, and can fall back to using
libguestfs file system calls.
If libguestfs was compiled without support for "guestfs_mount_local" then calling it will return an error
with errno set to "ENOTSUP" (see "guestfs_last_errno").
MOUNT LOCAL PERFORMANCE
Libguestfs on top of FUSE performs quite poorly. For best performance do not use it. Use ordinary
libguestfs filesystem calls, upload, download etc. instead.
HOTPLUGGING
In libguestfs ≥ 1.20, you may add drives and remove after calling "guestfs_launch". There are some
restrictions, see below. This is called hotplugging.
Only a subset of the backends support hotplugging (currently only the libvirt backend has support). It
also requires that you use libvirt ≥ 0.10.3 and qemu ≥ 1.2.
To hot-add a disk, simply call "guestfs_add_drive_opts" after "guestfs_launch". It is mandatory to
specify the "label" parameter so that the newly added disk has a predictable name. For example:
if (guestfs_launch (g) == -1)
error ("launch failed");
if (guestfs_add_drive_opts (g, filename,
GUESTFS_ADD_DRIVE_OPTS_LABEL, "newdisk",
-1) == -1)
error ("hot-add of disk failed");
if (guestfs_part_disk ("/dev/disk/guestfs/newdisk", "mbr") == -1)
error ("partitioning of hot-added disk failed");
To hot-remove a disk, call "guestfs_remove_drive". You can call this before or after "guestfs_launch".
You can only remove disks that were previously added with a label.
Backends that support hotplugging do not require that you add ≥ 1 disk before calling launch. When
hotplugging is supported you don't need to add any disks.
REMOTE STORAGE
CEPH
Libguestfs can access Ceph (librbd/RBD) disks.
To do this, set the optional "protocol" and "server" parameters of "guestfs_add_drive_opts" like this:
char **servers = { "ceph1.example.org:3000", /* ... */, NULL };
guestfs_add_drive_opts (g, "/pool/image",
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "rbd",
GUESTFS_ADD_DRIVE_OPTS_SERVER, servers,
GUESTFS_ADD_DRIVE_OPTS_USERNAME, "rbduser",
GUESTFS_ADD_DRIVE_OPTS_SECRET, "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA==",
-1);
"servers" (the "server" parameter) is a list of one or more Ceph servers. The server string is
documented in "guestfs_add_drive_opts". The "username" and "secret" parameters are also optional, and if
not given, then no authentication will be used.
FTP, HTTP AND TFTP
Libguestfs can access remote disks over FTP, FTPS, HTTP, HTTPS or TFTP protocols.
To do this, set the optional "protocol" and "server" parameters of "guestfs_add_drive_opts" like this:
char **servers = { "www.example.org", NULL };
guestfs_add_drive_opts (g, "/disk.img",
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "http",
GUESTFS_ADD_DRIVE_OPTS_SERVER, servers,
-1);
The "protocol" can be one of "ftp", "ftps", "http", "https" or "tftp".
"servers" (the "server" parameter) is a list which must have a single element. The single element is a
string defining the web, FTP or TFTP server. The format of this string is documented in
"guestfs_add_drive_opts".
GLUSTER
Libguestfs can access Gluster disks.
To do this, set the optional "protocol" and "server" parameters of "guestfs_add_drive_opts" like this:
char **servers = { "gluster.example.org:24007", NULL };
guestfs_add_drive_opts (g, "/volname/image",
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "gluster",
GUESTFS_ADD_DRIVE_OPTS_SERVER, servers,
-1);
"servers" (the "server" parameter) is a list which must have a single element. The single element is a
string defining the Gluster server. The format of this string is documented in "guestfs_add_drive_opts".
Note that gluster usually requires the client process (ie. libguestfs) to run as root and will give
unfathomable errors if it is not (eg. "No data available").
ISCSI
Libguestfs can access iSCSI disks remotely.
To do this, set the optional "protocol" and "server" parameters like this:
char **server = { "iscsi.example.org:3000", NULL };
guestfs_add_drive_opts (g, "/target-iqn-name/lun",
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "iscsi",
GUESTFS_ADD_DRIVE_OPTS_SERVER, server,
-1);
The "server" parameter is a list which must have a single element. The single element is a string
defining the iSCSI server. The format of this string is documented in "guestfs_add_drive_opts".
NETWORK BLOCK DEVICE
Libguestfs can access Network Block Device (NBD) disks remotely.
To do this, set the optional "protocol" and "server" parameters of "guestfs_add_drive_opts" like this:
char **server = { "nbd.example.org:3000", NULL };
guestfs_add_drive_opts (g, "" /* export name - see below */,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "nbd",
GUESTFS_ADD_DRIVE_OPTS_SERVER, server,
-1);
Notes:
• "server" is in fact a list of servers. For NBD you must always supply a list with a single element.
(Other remote protocols require zero or more than one server, hence the requirement for this
parameter to be a list).
• The "server" string is documented in "guestfs_add_drive_opts". To connect to a local qemu-nbd
instance over a Unix domain socket, use "unix:/path/to/socket".
• The "filename" parameter is the NBD export name. Use an empty string to mean the default export.
Many NBD servers, including qemu-nbd, do not support export names.
• If using qemu-nbd as your server, you should always specify the "-t" option. The reason is that
libguestfs may open several connections to the server.
• The libvirt backend requires that you set the "format" parameter of "guestfs_add_drive_opts"
accurately when you use writable NBD disks.
• The libvirt backend has a bug that stops Unix domain socket connections from working:
https://bugzilla.redhat.com/show_bug.cgi?id=922888
• The direct backend does not support readonly connections because of a bug in qemu:
https://bugs.launchpad.net/qemu/+bug/1155677
SHEEPDOG
Libguestfs can access Sheepdog disks.
To do this, set the optional "protocol" and "server" parameters of "guestfs_add_drive_opts" like this:
char **servers = { /* optional servers ... */ NULL };
guestfs_add_drive_opts (g, "/volume",
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "sheepdog",
GUESTFS_ADD_DRIVE_OPTS_SERVER, servers,
-1);
The optional list of "servers" may be zero or more server addresses ("hostname:port"). The format of the
server strings is documented in "guestfs_add_drive_opts".
SSH
Libguestfs can access disks over a Secure Shell (SSH) connection.
To do this, set the "protocol" and "server" and (optionally) "username" parameters of
"guestfs_add_drive_opts" like this:
char **server = { "remote.example.com", NULL };
guestfs_add_drive_opts (g, "/path/to/disk.img",
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "ssh",
GUESTFS_ADD_DRIVE_OPTS_SERVER, server,
GUESTFS_ADD_DRIVE_OPTS_USERNAME, "remoteuser",
-1);
The format of the server string is documented in "guestfs_add_drive_opts".
INSPECTION
Libguestfs has APIs for inspecting an unknown disk image to find out if it contains operating systems, an
install CD or a live CD.
Add all disks belonging to the unknown virtual machine and call "guestfs_launch" in the usual way.
Then call "guestfs_inspect_os". This function uses other libguestfs calls and certain heuristics, and
returns a list of operating systems that were found. An empty list means none were found. A single
element is the root filesystem of the operating system. For dual- or multi-boot guests, multiple roots
can be returned, each one corresponding to a separate operating system. (Multi-boot virtual machines are
extremely rare in the world of virtualization, but since this scenario can happen, we have built
libguestfs to deal with it.)
For each root, you can then call various "guestfs_inspect_get_*" functions to get additional details
about that operating system. For example, call "guestfs_inspect_get_type" to return the string "windows"
or "linux" for Windows and Linux-based operating systems respectively.
Un*x-like and Linux-based operating systems usually consist of several filesystems which are mounted at
boot time (for example, a separate boot partition mounted on "/boot"). The inspection rules are able to
detect how filesystems correspond to mount points. Call "guestfs_inspect_get_mountpoints" to get this
mapping. It might return a hash table like this example:
/boot => /dev/sda1
/ => /dev/vg_guest/lv_root
/usr => /dev/vg_guest/lv_usr
The caller can then make calls to "guestfs_mount" to mount the filesystems as suggested.
Be careful to mount filesystems in the right order (eg. "/" before "/usr"). Sorting the keys of the hash
by length, shortest first, should work.
Inspection currently only works for some common operating systems. Contributors are welcome to send
patches for other operating systems that we currently cannot detect.
Encrypted disks must be opened before inspection. See "ENCRYPTED DISKS" for more details. The
"guestfs_inspect_os" function just ignores any encrypted devices.
A note on the implementation: The call "guestfs_inspect_os" performs inspection and caches the results in
the guest handle. Subsequent calls to "guestfs_inspect_get_*" return this cached information, but do not
re-read the disks. If you change the content of the guest disks, you can redo inspection by calling
"guestfs_inspect_os" again. ("guestfs_inspect_list_applications2" works a little differently from the
other calls and does read the disks. See documentation for that function for details).
INSPECTING INSTALL DISKS
Libguestfs (since 1.9.4) can detect some install disks, install CDs, live CDs and more.
Call "guestfs_inspect_get_format" to return the format of the operating system, which currently can be
"installed" (a regular operating system) or "installer" (some sort of install disk).
Further information is available about the operating system that can be installed using the regular
inspection APIs like "guestfs_inspect_get_product_name", "guestfs_inspect_get_major_version" etc.
Some additional information specific to installer disks is also available from the
"guestfs_inspect_is_live", "guestfs_inspect_is_netinst" and "guestfs_inspect_is_multipart" calls.
SPECIAL CONSIDERATIONS FOR WINDOWS GUESTS
Libguestfs can mount NTFS partitions. It does this using the http://www.ntfs-3g.org/ driver.
DRIVE LETTERS AND PATHS
DOS and Windows still use drive letters, and the filesystems are always treated as case insensitive by
Windows itself, and therefore you might find a Windows configuration file referring to a path like
"c:\windows\system32". When the filesystem is mounted in libguestfs, that directory might be referred to
as "/WINDOWS/System32".
Drive letter mappings can be found using inspection (see "INSPECTION" and
"guestfs_inspect_get_drive_mappings")
Dealing with separator characters (backslash vs forward slash) is outside the scope of libguestfs, but
usually a simple character replacement will work.
To resolve the case insensitivity of paths, call "guestfs_case_sensitive_path".
LONG FILENAMES ON NTFS
NTFS supports filenames up to 255 characters long. "Character" means a 2 byte UTF-16 codepoint which can
encode the most common Unicode codepoints.
Most Linux filesystems support filenames up to 255 bytes. This means you may get an error:
File name too long
when you copy a file from NTFS to a Linux filesystem if the name, when reencoded as UTF-8, would exceed
255 bytes in length.
This will most often happen when using non-ASCII names that are longer than ~127 characters (eg. Greek,
Cyrillic) or longer than ~85 characters (Asian languages).
A workaround is not to try to store such long filenames on Linux native filesystems. Since the tar(1)
format can store unlimited length filenames, keep the files in a tarball.
ACCESSING THE WINDOWS REGISTRY
Libguestfs also provides some help for decoding Windows Registry "hive" files, through a separate C
library called hivex(3).
Before libguestfs 1.19.35 you had to download the hive file, operate on it locally using hivex, and
upload it again. Since this version, we have included the major hivex APIs directly in the libguestfs
API (see "guestfs_hivex_open"). This means that if you have opened a Windows guest, you can read and
write the registry directly.
See also virt-win-reg(1).
SYMLINKS ON NTFS-3G FILESYSTEMS
Ntfs-3g tries to rewrite "Junction Points" and NTFS "symbolic links" to provide something which looks
like a Linux symlink. The way it tries to do the rewriting is described here:
http://www.tuxera.com/community/ntfs-3g-advanced/junction-points-and-symbolic-links/
The essential problem is that ntfs-3g simply does not have enough information to do a correct job. NTFS
links can contain drive letters and references to external device GUIDs that ntfs-3g has no way of
resolving. It is almost certainly the case that libguestfs callers should ignore what ntfs-3g does (ie.
don't use "guestfs_readlink" on NTFS volumes).
Instead if you encounter a symbolic link on an ntfs-3g filesystem, use "guestfs_lgetxattr" to read the
"system.ntfs_reparse_data" extended attribute, and read the raw reparse data from that (you can find the
format documented in various places around the web).
EXTENDED ATTRIBUTES ON NTFS-3G FILESYSTEMS
There are other useful extended attributes that can be read from ntfs-3g filesystems (using
"guestfs_getxattr"). See:
http://www.tuxera.com/community/ntfs-3g-advanced/extended-attributes/
WINDOWS HIBERNATION AND WINDOWS 8 FAST STARTUP
Windows guests which have been hibernated (instead of fully shut down) cannot be mounted. This is a
limitation of ntfs-3g. You will see an error like this:
The disk contains an unclean file system (0, 0).
Metadata kept in Windows cache, refused to mount.
Failed to mount '/dev/sda2': Operation not permitted
The NTFS partition is in an unsafe state. Please resume
and shutdown Windows fully (no hibernation or fast
restarting), or mount the volume read-only with the
'ro' mount option.
In Windows 8, the shutdown button does not shut down the guest at all. Instead it usually hibernates the
guest. This is known as "fast startup".
Some suggested workarounds are:
• Mount read-only (eg. "guestfs_mount_ro").
• On Windows 8, turn off fast startup. It is in the Control Panel → Power Options → Choose what the
power buttons do → Change settings that are currently unavailable → Turn on fast startup.
• On Windows 7 and earlier, shut the guest off properly instead of hibernating it.
RESIZE2FS ERRORS
The "guestfs_resize2fs", "guestfs_resize2fs_size" and "guestfs_resize2fs_M" calls are used to resize
ext2/3/4 filesystems.
The underlying program (resize2fs(8)) requires that the filesystem is clean and recently fsck'd before
you can resize it. Also, if the resize operation fails for some reason, then you had to call fsck the
filesystem again to fix it.
In libguestfs "lt" 1.17.14, you usually had to call "guestfs_e2fsck_f" before the resize. However, in
"ge" 1.17.14, e2fsck(8) is called automatically before the resize, so you no longer need to do this.
The resize2fs(8) program can still fail, in which case it prints an error message similar to:
Please run 'e2fsck -fy <device>' to fix the filesystem
after the aborted resize operation.
You can do this by calling "guestfs_e2fsck" with the "forceall" option. However in the context of disk
images, it is usually better to avoid this situation, eg. by rolling back to an earlier snapshot, or by
copying and resizing and on failure going back to the original.
USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES
Although we don't want to discourage you from using the C API, we will mention here that the same API is
also available in other languages.
The API is broadly identical in all supported languages. This means that the C call
"guestfs_add_drive_ro(g,file)" is "$g->add_drive_ro($file)" in Perl, "g.add_drive_ro(file)" in Python,
and "g#add_drive_ro file" in OCaml. In other words, a straightforward, predictable isomorphism between
each language.
Error messages are automatically transformed into exceptions if the language supports it.
We don't try to "object orientify" parts of the API in OO languages, although contributors are welcome to
write higher level APIs above what we provide in their favourite languages if they wish.
C++ You can use the guestfs.h header file from C++ programs. The C++ API is identical to the C API. C++
classes and exceptions are not used.
C# The C# bindings are highly experimental. Please read the warnings at the top of
"csharp/Libguestfs.cs".
Erlang
See guestfs-erlang(3).
GObject
Experimental GObject bindings (with GObject Introspection support) are available. See the "gobject"
directory in the source.
Go See <guestfs-golang(3)>.
Haskell
This language binding is working but incomplete:
• Functions with optional arguments are not bound. Implementing optional arguments in Haskell
seems to be very complex.
• Events are not bound.
• Functions with the following return types are not bound:
• Any function returning a struct.
• Any function returning a list of structs.
• A few functions that return fixed length buffers (specifically ones declared "RBufferOut" in
the generator).
• A tiny number of obscure functions that return constant strings (specifically ones declared
"RConstOptString" in the generator).
Java
Full documentation is contained in the Javadoc which is distributed with libguestfs. For examples,
see guestfs-java(3).
Lua See guestfs-lua(3).
OCaml
See guestfs-ocaml(3).
Perl
See guestfs-perl(3) and Sys::Guestfs(3).
PHP For documentation see "README-PHP" supplied with libguestfs sources or in the php-libguestfs package
for your distribution.
The PHP binding only works correctly on 64 bit machines.
Python
See guestfs-python(3).
Ruby
See guestfs-ruby(3).
For JRuby, use the Java bindings.
shell scripts
See guestfish(1).
LIBGUESTFS GOTCHAS
http://en.wikipedia.org/wiki/Gotcha_(programming): "A feature of a system [...] that works in the way it
is documented but is counterintuitive and almost invites mistakes."
Since we developed libguestfs and the associated tools, there are several things we would have designed
differently, but are now stuck with for backwards compatibility or other reasons. If there is ever a
libguestfs 2.0 release, you can expect these to change. Beware of them.
Read-only should be the default.
In guestfish(3), --ro should be the default, and you should have to specify --rw if you want to make
changes to the image.
This would reduce the potential to corrupt live VM images.
Note that many filesystems change the disk when you just mount and unmount, even if you didn't
perform any writes. You need to use "guestfs_add_drive_ro" to guarantee that the disk is not
changed.
guestfish command line is hard to use.
"guestfish disk.img" doesn't do what people expect (open "disk.img" for examination). It tries to
run a guestfish command "disk.img" which doesn't exist, so it fails. In earlier versions of
guestfish the error message was also unintuitive, but we have corrected this since. Like the Bourne
shell, we should have used "guestfish -c command" to run commands.
guestfish megabyte modifiers don't work right on all commands
In recent guestfish you can use "1M" to mean 1 megabyte (and similarly for other modifiers). What
guestfish actually does is to multiply the number part by the modifier part and pass the result to
the C API. However this doesn't work for a few APIs which aren't expecting bytes, but are already
expecting some other unit (eg. megabytes).
The most common is "guestfs_lvcreate". The guestfish command:
lvcreate LV VG 100M
does not do what you might expect. Instead because "guestfs_lvcreate" is already expecting
megabytes, this tries to create a 100 terabyte (100 megabytes * megabytes) logical volume. The error
message you get from this is also a little obscure.
This could be fixed in the generator by specially marking parameters and return values which take
bytes or other units.
Ambiguity between devices and paths
There is a subtle ambiguity in the API between a device name (eg. "/dev/sdb2") and a similar
pathname. A file might just happen to be called "sdb2" in the directory "/dev" (consider some non-
Unix VM image).
In the current API we usually resolve this ambiguity by having two separate calls, for example
"guestfs_checksum" and "guestfs_checksum_device". Some API calls are ambiguous and (incorrectly)
resolve the problem by detecting if the path supplied begins with "/dev/".
To avoid both the ambiguity and the need to duplicate some calls, we could make paths/devices into
structured names. One way to do this would be to use a notation like grub ("hd(0,0)"), although
nobody really likes this aspect of grub. Another way would be to use a structured type, equivalent
to this OCaml type:
type path = Path of string | Device of int | Partition of int * int
which would allow you to pass arguments like:
Path "/foo/bar"
Device 1 (* /dev/sdb, or perhaps /dev/sda *)
Partition (1, 2) (* /dev/sdb2 (or is it /dev/sda2 or /dev/sdb3?) *)
Path "/dev/sdb2" (* not a device *)
As you can see there are still problems to resolve even with this representation. Also consider how
it might work in guestfish.
KEYS AND PASSPHRASES
Certain libguestfs calls take a parameter that contains sensitive key material, passed in as a C string.
In the future we would hope to change the libguestfs implementation so that keys are mlock(2)-ed into
physical RAM, and thus can never end up in swap. However this is not done at the moment, because of the
complexity of such an implementation.
Therefore you should be aware that any key parameter you pass to libguestfs might end up being written
out to the swap partition. If this is a concern, scrub the swap partition or don't use libguestfs on
encrypted devices.
MULTIPLE HANDLES AND MULTIPLE THREADS
All high-level libguestfs actions are synchronous. If you want to use libguestfs asynchronously then you
must create a thread.
Only use the handle from a single thread. Either use the handle exclusively from one thread, or provide
your own mutex so that two threads cannot issue calls on the same handle at the same time. Even
apparently innocent functions like "guestfs_get_trace" are not safe to be called from multiple threads
without a mutex.
See the graphical program guestfs-browser for one possible architecture for multithreaded programs using
libvirt and libguestfs.
PATH
Libguestfs needs a supermin appliance, which it finds by looking along an internal path.
By default it looks for these in the directory "$libdir/guestfs" (eg. "/usr/local/lib/guestfs" or
"/usr/lib64/guestfs").
Use "guestfs_set_path" or set the environment variable "LIBGUESTFS_PATH" to change the directories that
libguestfs will search in. The value is a colon-separated list of paths. The current directory is not
searched unless the path contains an empty element or ".". For example
"LIBGUESTFS_PATH=:/usr/lib/guestfs" would search the current directory and then "/usr/lib/guestfs".
QEMU WRAPPERS
If you want to compile your own qemu, run qemu from a non-standard location, or pass extra arguments to
qemu, then you can write a shell-script wrapper around qemu.
There is one important rule to remember: you must "exec qemu" as the last command in the shell script (so
that qemu replaces the shell and becomes the direct child of the libguestfs-using program). If you don't
do this, then the qemu process won't be cleaned up correctly.
Here is an example of a wrapper, where I have built my own copy of qemu from source:
#!/bin/sh -
qemudir=/home/rjones/d/qemu
exec $qemudir/x86_64-softmmu/qemu-system-x86_64 -L $qemudir/pc-bios "$@"
Save this script as "/tmp/qemu.wrapper" (or wherever), "chmod +x", and then use it by setting the
LIBGUESTFS_HV environment variable. For example:
LIBGUESTFS_HV=/tmp/qemu.wrapper guestfish
Note that libguestfs also calls qemu with the -help and -version options in order to determine features.
Wrappers can also be used to edit the options passed to qemu. In the following example, the "-machine
..." option ("-machine" and the following argument) are removed from the command line and replaced with
"-machine pc,accel=tcg". The while loop iterates over the options until it finds the right one to
remove, putting the remaining options into the "args" array.
#!/bin/bash -
i=0
while [ $# -gt 0 ]; do
case "$1" in
-machine)
shift 2;;
*)
args[i]="$1"
(( i++ ))
shift ;;
esac
done
exec qemu-kvm -machine pc,accel=tcg "${args[@]}"
BACKEND
The backend (previously known as the "attach method") controls how libguestfs creates and/or connects to
the backend daemon, eg. by starting qemu directly, or using libvirt to manage an appliance, running User-
Mode Linux, or connecting to an already running daemon.
You can set the backend by calling "guestfs_set_backend", or by setting the environment variable
"LIBGUESTFS_BACKEND".
Possible backends are described below:
"direct"
"appliance"
Run qemu directly to launch an appliance.
"direct" and "appliance" are synonyms.
This is the ordinary method and normally the default, but see the note below.
"libvirt"
"libvirt:URI"
Use libvirt to launch and manage the appliance.
The optional URI is the libvirt connection URI to use (see http://libvirt.org/uri.html). The typical
libvirt backend with a URI would be "libvirt:qemu:///session"
The libvirt backend supports more features, including hotplugging (see "HOTPLUGGING") and sVirt.
"uml"
Run the User-Mode Linux kernel. The location of the kernel is set using $LIBGUESTFS_HV or using the
"guestfs_set_qemu" API (note that qemu is not involved, we just reuse the same variable in the handle
for convenience).
User-Mode Linux can be much faster, simpler and more lightweight than using a full-blown virtual
machine, but it also has some shortcomings. See "USER-MODE LINUX BACKEND" below.
"unix:path"
Connect to the Unix domain socket path.
This method lets you connect to an existing daemon or (using virtio-serial) to a live guest. For
more information, see "ATTACHING TO RUNNING DAEMONS".
"direct" is usually the default backend. However since libguestfs ≥ 1.19.24, libguestfs can be built
with a different default by doing:
./configure --with-default-backend=...
To find out if libguestfs was compiled with a different default backend, do:
unset LIBGUESTFS_BACKEND
guestfish get-backend
ATTACHING TO RUNNING DAEMONS
Note (1): This is highly experimental and has a tendency to eat babies. Use with caution.
Note (2): This section explains how to attach to a running daemon from a low level perspective. For most
users, simply using virt tools such as guestfish(1) with the --live option will "just work".
Using guestfs_set_backend
By calling "guestfs_set_backend" you can change how the library connects to the "guestfsd" daemon in
"guestfs_launch" (read "ARCHITECTURE" for some background).
The normal backend is "direct", where a small appliance is created containing the daemon, and then the
library connects to this. "libvirt" or "libvirt:URI" are alternatives that use libvirt to start the
appliance.
Setting the backend to "unix:path" (where path is the path of a Unix domain socket) causes
"guestfs_launch" to connect to an existing daemon over the Unix domain socket.
The normal use for this is to connect to a running virtual machine that contains a "guestfsd" daemon, and
send commands so you can read and write files inside the live virtual machine.
Using guestfs_add_domain with live flag
"guestfs_add_domain" provides some help for getting the correct backend. If you pass the "live" option
to this function, then (if the virtual machine is running) it will examine the libvirt XML looking for a
virtio-serial channel to connect to:
<domain>
...
<devices>
...
<channel type='unix'>
<source mode='bind' path='/path/to/socket'/>
<target type='virtio' name='org.libguestfs.channel.0'/>
</channel>
...
</devices>
</domain>
"guestfs_add_domain" extracts "/path/to/socket" and sets the backend to "unix:/path/to/socket".
Some of the libguestfs tools (including guestfish) support a --live option which is passed through to
"guestfs_add_domain" thus allowing you to attach to and modify live virtual machines.
The virtual machine needs to have been set up beforehand so that it has the virtio-serial channel and so
that guestfsd is running inside it.
USER-MODE LINUX BACKEND
Setting the following environment variables (or the equivalent in the API) selects the User-Mode Linux
backend:
export LIBGUESTFS_BACKEND=uml
export LIBGUESTFS_HV=/path/to/vmlinux
"vmlinux" (or it may be called "linux") is the Linux binary, compiled to run as a userspace process.
Note that we reuse the qemu variable in the handle for convenience; qemu is not involved.
User-Mode Linux can be faster and more lightweight than running a full-blown virtual machine as the
backend (especially if you are already running libguestfs in a virtual machine or cloud instance), but it
also has some shortcomings compared to the usual qemu/KVM-based backend.
BUILDING USER-MODE LINUX FROM SOURCE
Your Linux distro may provide UML in which case you can ignore this section.
These instructions are adapted from: http://user-mode-linux.sourceforge.net/source.html
1. Check out Linux sources
Clone the Linux git repository or download the Linux source tarball.
2. Configure the kernel
Note: All 'make' commands must have "ARCH=um" added.
make menuconfig ARCH=um
Make sure any filesystem drivers that you need are compiled into the kernel.
Currently, it needs a large amount of extra work to get modules working. It's recommended that you
disable module support in the kernel configuration, which will cause everything to be compiled into
the image.
3. Build the kernel
make ARCH=um
This will leave a file called "linux" or "vmlinux" in the top-level directory. This is the UML
kernel. You should set "LIBGUESTFS_HV" to point to this file.
USER-MODE LINUX DIFFERENCES FROM KVM
UML only supports raw-format images
Only plain raw-format images will work. No qcow2, no backing files.
UML does not support any remote drives
No NBD, etc.
UML only works on ix86 and x86-64
UML is experimental
In particular, support for UML in libguestfs depends on support for UML in the upstream kernel. If
UML was ever removed from the upstream Linux kernel, then we might remove it from libguestfs too.
ABI GUARANTEE
We guarantee the libguestfs ABI (binary interface), for public, high-level actions as outlined in this
section. Although we will deprecate some actions, for example if they get replaced by newer calls, we
will keep the old actions forever. This allows you the developer to program in confidence against the
libguestfs API.
BLOCK DEVICE NAMING
In the kernel there is now quite a profusion of schemata for naming block devices (in this context, by
block device I mean a physical or virtual hard drive). The original Linux IDE driver used names starting
with "/dev/hd*". SCSI devices have historically used a different naming scheme, "/dev/sd*". When the
Linux kernel libata driver became a popular replacement for the old IDE driver (particularly for SATA
devices) those devices also used the "/dev/sd*" scheme. Additionally we now have virtual machines with
paravirtualized drivers. This has created several different naming systems, such as "/dev/vd*" for
virtio disks and "/dev/xvd*" for Xen PV disks.
As discussed above, libguestfs uses a qemu appliance running an embedded Linux kernel to access block
devices. We can run a variety of appliances based on a variety of Linux kernels.
This causes a problem for libguestfs because many API calls use device or partition names. Working
scripts and the recipe (example) scripts that we make available over the internet could fail if the
naming scheme changes.
Therefore libguestfs defines "/dev/sd*" as the standard naming scheme. Internally "/dev/sd*" names are
translated, if necessary, to other names as required. For example, under RHEL 5 which uses the
"/dev/hd*" scheme, any device parameter "/dev/sda2" is translated to "/dev/hda2" transparently.
Note that this only applies to parameters. The "guestfs_list_devices", "guestfs_list_partitions" and
similar calls return the true names of the devices and partitions as known to the appliance, but see
"guestfs_canonical_device_name".
DISK LABELS
In libguestfs ≥ 1.20, you can give a label to a disk when you add it, using the optional "label"
parameter to "guestfs_add_drive_opts". (Note that disk labels are different from and not related to
filesystem labels).
Not all versions of libguestfs support setting a disk label, and when it is supported, it is limited to
20 ASCII characters "[a-zA-Z]".
When you add a disk with a label, it can either be addressed using "/dev/sd*", or using
"/dev/disk/guestfs/label". Partitions on the disk can be addressed using
"/dev/disk/guestfs/labelpartnum".
Listing devices ("guestfs_list_devices") and partitions ("guestfs_list_partitions") returns the raw block
device name. However you can use "guestfs_list_disk_labels" to map disk labels to raw block device and
partition names.
ALGORITHM FOR BLOCK DEVICE NAME TRANSLATION
Usually this translation is transparent. However in some (very rare) cases you may need to know the
exact algorithm. Such cases include where you use "guestfs_config" to add a mixture of virtio and IDE
devices to the qemu-based appliance, so have a mixture of "/dev/sd*" and "/dev/vd*" devices.
The algorithm is applied only to parameters which are known to be either device or partition names.
Return values from functions such as "guestfs_list_devices" are never changed.
• Is the string a parameter which is a device or partition name?
• Does the string begin with "/dev/sd"?
• Does the named device exist? If so, we use that device. However if not then we continue with this
algorithm.
• Replace initial "/dev/sd" string with "/dev/hd".
For example, change "/dev/sda2" to "/dev/hda2".
If that named device exists, use it. If not, continue.
• Replace initial "/dev/sd" string with "/dev/vd".
If that named device exists, use it. If not, return an error.
PORTABILITY CONCERNS WITH BLOCK DEVICE NAMING
Although the standard naming scheme and automatic translation is useful for simple programs and guestfish
scripts, for larger programs it is best not to rely on this mechanism.
Where possible for maximum future portability programs using libguestfs should use these future-proof
techniques:
• Use "guestfs_list_devices" or "guestfs_list_partitions" to list actual device names, and then use
those names directly.
Since those device names exist by definition, they will never be translated.
• Use higher level ways to identify filesystems, such as LVM names, UUIDs and filesystem labels.
NULL DISKS
When adding a disk using, eg., "guestfs_add_drive", you can set the filename to "/dev/null". This string
is treated specially by libguestfs, causing it to add a "null disk".
A null disk has the following properties:
• A null disk will appear as a normal device, eg. in calls to "guestfs_list_devices".
• You may add "/dev/null" multiple times.
• You should not try to access a null disk in any way. For example, you shouldn't try to read it or
mount it.
Null disks are used for three main purposes:
1. Performance testing of libguestfs (see guestfs-performance(1)).
2. The internal test suite.
3. If you want to use libguestfs APIs that don't refer to disks, since libguestfs requires that at least
one disk is added, you should add a null disk.
For example, to test if a feature is available, use code like this:
guestfs_h *g;
char **groups = [ "btrfs", NULL ];
g = guestfs_create ();
guestfs_add_drive (g, "/dev/null");
guestfs_launch (g);
if (guestfs_available (g, groups) == 0) {
// group(s) are available
} else {
// group(s) are not available
}
guestfs_close (g);
DISK IMAGE FORMATS
Virtual disks come in a variety of formats. Some common formats are listed below.
Note that libguestfs itself is not responsible for handling the disk format: this is done using qemu(1).
If support for a particular format is missing or broken, this has to be fixed in qemu.
COMMON VIRTUAL DISK IMAGE FORMATS
raw Raw format is simply a dump of the sequential bytes of the virtual hard disk. There is no header,
container, compression or processing of any sort.
Since raw format requires no translation to read or write, it is both fast and very well supported by
qemu and all other hypervisors. You can consider it to be a universal format that any hypervisor can
access.
Raw format files are not compressed and so take up the full space of the original disk image even
when they are empty. A variation (on Linux/Unix at least) is to not store ranges of all-zero bytes
by storing the file as a sparse file. This "variant format" is sometimes called raw sparse. Many
utilities, including virt-sparsify(1), can make raw disk images sparse.
qcow2
Qcow2 is the native disk image format used by qemu. Internally it uses a two-level directory
structure so that only blocks containing data are stored in the file. It also has many other
features such as compression, snapshots and backing files.
There are at least two distinct variants of this format, although qemu (and hence libguestfs) handles
both transparently to the user.
vmdk
VMDK is VMware's native disk image format. There are many variations. Modern qemu (hence
libguestfs) supports most variations, but you should be aware that older versions of qemu had some
very bad data-corrupting bugs in this area.
Note that VMware ESX exposes files with the name "guest-flat.vmdk". These are not VMDK. They are
raw format files which happen to have a ".vmdk" extension.
vdi VDI is VirtualBox's native disk image format. Qemu (hence libguestfs) has generally good support for
this.
vpc
vhd VPC (old) and VHD (modern) are the native disk image format of Microsoft (and previously, Connectix)
Virtual PC and Hyper-V.
Obsolete formats
The following formats are obsolete and should not be used: qcow (aka qcow1), cow, bochs.
DETECTING THE FORMAT OF A DISK IMAGE
Firstly note there is a security issue with auto-detecting the format of a disk image. It may or may not
apply in your use case. Read "CVE-2010-3851" below.
Libguestfs offers an API to get the format of a disk image ("guestfs_disk_format", and it is safest to
use this.
Don't be tempted to try parsing the text / human-readable output of "qemu-img" since it cannot be parsed
reliably and securely. Also do not use the "file" command since the output of that changes over time.
SECURITY
This section discusses security implications of using libguestfs, particularly with untrusted or
malicious guests or disk images.
SECURITY OF MOUNTING FILESYSTEMS
You should never mount an untrusted guest filesystem directly on your host kernel (eg. using loopback or
kpartx).
When you mount a filesystem, mistakes in the kernel filesystem (VFS) can be escalated into exploits by
attackers creating a malicious filesystem. These exploits are very severe for two reasons. Firstly
there are very many filesystem drivers in the kernel, and many of them are infrequently used and not much
developer attention has been paid to the code. Linux userspace helps potential crackers by detecting the
filesystem type and automatically choosing the right VFS driver, even if that filesystem type is
unexpected. Secondly, a kernel-level exploit is like a local root exploit (worse in some ways), giving
immediate and total access to the system right down to the hardware level.
These exploits can be present in the kernel for a very long time (https://lwn.net/Articles/538898/).
Libguestfs provides a layered approach to protecting you from exploits:
untrusted filesystem
--------------------------------------
appliance kernel
--------------------------------------
qemu process running as non-root
--------------------------------------
sVirt [if using libvirt + SELinux]
--------------------------------------
host kernel
We run a Linux kernel inside a qemu virtual machine, usually running as a non-root user. The attacker
would need to write a filesystem which first exploited the kernel, and then exploited either qemu
virtualization (eg. a faulty qemu driver) or the libguestfs protocol, and finally to be as serious as the
host kernel exploit it would need to escalate its privileges to root. Additionally if you use the
libvirt back end and SELinux, sVirt is used to confine the qemu process. This multi-step escalation,
performed by a static piece of data, is thought to be extremely hard to do, although we never say 'never'
about security issues.
Callers can also reduce the attack surface by forcing the filesystem type when mounting (use
"guestfs_mount_vfs").
GENERAL SECURITY CONSIDERATIONS
Be careful with any files or data that you download from a guest (by "download" we mean not just the
"guestfs_download" command but any command that reads files, filenames, directories or anything else from
a disk image). An attacker could manipulate the data to fool your program into doing the wrong thing.
Consider cases such as:
• the data (file etc) not being present
• being present but empty
• being much larger than normal
• containing arbitrary 8 bit data
• being in an unexpected character encoding
• containing homoglyphs.
PROTOCOL SECURITY
The protocol is designed to be secure, being based on RFC 4506 (XDR) with a defined upper message size.
However a program that uses libguestfs must also take care - for example you can write a program that
downloads a binary from a disk image and executes it locally, and no amount of protocol security will
save you from the consequences.
INSPECTION SECURITY
Parts of the inspection API (see "INSPECTION") return untrusted strings directly from the guest, and
these could contain any 8 bit data. Callers should be careful to escape these before printing them to a
structured file (for example, use HTML escaping if creating a web page).
Guest configuration may be altered in unusual ways by the administrator of the virtual machine, and may
not reflect reality (particularly for untrusted or actively malicious guests). For example we parse the
hostname from configuration files like "/etc/sysconfig/network" that we find in the guest, but the guest
administrator can easily manipulate these files to provide the wrong hostname.
The inspection API parses guest configuration using two external libraries: Augeas (Linux configuration)
and hivex (Windows Registry). Both are designed to be robust in the face of malicious data, although
denial of service attacks are still possible, for example with oversized configuration files.
RUNNING UNTRUSTED GUEST COMMANDS
Be very cautious about running commands from the guest. By running a command in the guest, you are
giving CPU time to a binary that you do not control, under the same user account as the library, albeit
wrapped in qemu virtualization. More information and alternatives can be found in the section "RUNNING
COMMANDS".
CVE-2010-3851
https://bugzilla.redhat.com/642934
This security bug concerns the automatic disk format detection that qemu does on disk images.
A raw disk image is just the raw bytes, there is no header. Other disk images like qcow2 contain a
special header. Qemu deals with this by looking for one of the known headers, and if none is found then
assuming the disk image must be raw.
This allows a guest which has been given a raw disk image to write some other header. At next boot (or
when the disk image is accessed by libguestfs) qemu would do autodetection and think the disk image
format was, say, qcow2 based on the header written by the guest.
This in itself would not be a problem, but qcow2 offers many features, one of which is to allow a disk
image to refer to another image (called the "backing disk"). It does this by placing the path to the
backing disk into the qcow2 header. This path is not validated and could point to any host file (eg.
"/etc/passwd"). The backing disk is then exposed through "holes" in the qcow2 disk image, which of
course is completely under the control of the attacker.
In libguestfs this is rather hard to exploit except under two circumstances:
1. You have enabled the network or have opened the disk in write mode.
2. You are also running untrusted code from the guest (see "RUNNING COMMANDS").
The way to avoid this is to specify the expected disk format when adding disks (the optional "format"
option to "guestfs_add_drive_opts"). You should always do this if the disk is raw format, and it's a
good idea for other cases too. (See also "DISK IMAGE FORMATS").
For disks added from libvirt using calls like "guestfs_add_domain", the format is fetched from libvirt
and passed through.
For libguestfs tools, use the --format command line parameter as appropriate.
CVE-2011-4127
https://bugzilla.redhat.com/752375
This is a bug in the kernel which allowed guests to overwrite parts of the host's drives which they
should not normally have access to.
It is sufficient to update libguestfs to any version ≥ 1.16 which contains a change that mitigates the
problem.
CVE-2012-2690
https://bugzilla.redhat.com/831117
Old versions of both virt-edit and the guestfish "edit" command created a new file containing the changes
but did not set the permissions, etc of the new file to match the old one. The result of this was that
if you edited a security sensitive file such as "/etc/shadow" then it would be left world-readable after
the edit.
It is sufficient to update libguestfs to any version ≥ 1.16.
CVE-2013-2124
https://bugzilla.redhat.com/968306
This security bug was a flaw in inspection where an untrusted guest using a specially crafted file in the
guest OS could cause a double-free in the C library (denial of service).
It is sufficient to update libguestfs to a version that is not vulnerable: libguestfs ≥ 1.20.8, ≥ 1.22.2
or ≥ 1.23.2.
CVE-2013-4419
https://bugzilla.redhat.com/1016960
When using the guestfish(1) --remote or guestfish --listen options, guestfish would create a socket in a
known location ("/tmp/.guestfish-$UID/socket-$PID").
The location has to be a known one in order for both ends to communicate. However no checking was done
that the containing directory ("/tmp/.guestfish-$UID") is owned by the user. Thus another user could
create this directory and potentially hijack sockets owned by another user's guestfish client or server.
It is sufficient to update libguestfs to a version that is not vulnerable: libguestfs ≥ 1.20.12, ≥ 1.22.7
or ≥ 1.24.
CONNECTION MANAGEMENT
guestfs_h *
"guestfs_h" is the opaque type representing a connection handle. Create a handle by calling
"guestfs_create" or "guestfs_create_flags". Call "guestfs_close" to free the handle and release all
resources used.
For information on using multiple handles and threads, see the section "MULTIPLE HANDLES AND MULTIPLE
THREADS" above.
guestfs_create
guestfs_h *guestfs_create (void);
Create a connection handle.
On success this returns a non-NULL pointer to a handle. On error it returns NULL.
You have to "configure" the handle after creating it. This includes calling "guestfs_add_drive_opts" (or
one of the equivalent calls) on the handle at least once.
After configuring the handle, you have to call "guestfs_launch".
You may also want to configure error handling for the handle. See the "ERROR HANDLING" section below.
guestfs_create_flags
guestfs_h *guestfs_create_flags (unsigned flags [, ...]);
Create a connection handle, supplying extra flags and extra arguments to control how the handle is
created.
On success this returns a non-NULL pointer to a handle. On error it returns NULL.
"guestfs_create" is equivalent to calling guestfs_create_flags(0).
The following flags may be logically ORed together. (Currently no extra arguments are used).
"GUESTFS_CREATE_NO_ENVIRONMENT"
Don't parse any environment variables (such as "LIBGUESTFS_DEBUG" etc).
You can call "guestfs_parse_environment" or "guestfs_parse_environment_list" afterwards to parse
environment variables. Alternately, don't call these functions if you want the handle to be
unaffected by environment variables. See the example below.
The default (if this flag is not given) is to implicitly call "guestfs_parse_environment".
"GUESTFS_CREATE_NO_CLOSE_ON_EXIT"
Don't try to close the handle in an atexit(3) handler if the program exits without explicitly closing
the handle.
The default (if this flag is not given) is to install such an atexit handler.
USING "GUESTFS_CREATE_NO_ENVIRONMENT"
You might use "GUESTFS_CREATE_NO_ENVIRONMENT" and an explicit call to "guestfs_parse_environment" like
this:
guestfs_h *g;
int r;
g = guestfs_create_flags (GUESTFS_CREATE_NO_ENVIRONMENT);
if (!g) {
perror ("guestfs_create_flags");
exit (EXIT_FAILURE);
}
r = guestfs_parse_environment (g);
if (r == -1)
exit (EXIT_FAILURE);
Or to create a handle which is unaffected by environment variables, omit the call to
"guestfs_parse_environment" from the above code.
The above code has another advantage which is that any errors from parsing the environment are passed
through the error handler, whereas "guestfs_create" prints errors on stderr and ignores them.
guestfs_close
void guestfs_close (guestfs_h *g);
This closes the connection handle and frees up all resources used. If a close callback was set on the
handle, then it is called.
The correct way to close the handle is:
if (guestfs_shutdown (g) == -1) {
/* handle write errors here */
}
guestfs_close (g);
"guestfs_shutdown" is only needed if all of the following are true:
1. one or more disks were added in read-write mode, and
2. guestfs_launch was called, and
3. you made some changes, and
4. you have a way to handle write errors (eg. by exiting with an error code or reporting something to
the user).
ERROR HANDLING
API functions can return errors. For example, almost all functions that return "int" will return "-1" to
indicate an error.
Additional information is available for errors: an error message string and optionally an error number
(errno) if the thing that failed was a system call.
You can get at the additional information about the last error on the handle by calling
"guestfs_last_error", "guestfs_last_errno", and/or by setting up an error handler with
"guestfs_set_error_handler".
When the handle is created, a default error handler is installed which prints the error message string to
"stderr". For small short-running command line programs it is sufficient to do:
if (guestfs_launch (g) == -1)
exit (EXIT_FAILURE);
since the default error handler will ensure that an error message has been printed to "stderr" before the
program exits.
For other programs the caller will almost certainly want to install an alternate error handler or do
error handling in-line as in the example below. The non-C language bindings all install NULL error
handlers and turn errors into exceptions using code similar to this:
const char *msg;
int errnum;
/* This disables the default behaviour of printing errors
on stderr. */
guestfs_set_error_handler (g, NULL, NULL);
if (guestfs_launch (g) == -1) {
/* Examine the error message and print it, throw it,
etc. */
msg = guestfs_last_error (g);
errnum = guestfs_last_errno (g);
fprintf (stderr, "%s", msg);
if (errnum != 0)
fprintf (stderr, ": %s", strerror (errnum));
fprintf (stderr, "\n");
/* ... */
}
"guestfs_create" returns "NULL" if the handle cannot be created, and because there is no handle if this
happens there is no way to get additional error information. Since libguestfs ≥ 1.20, you can use
"guestfs_create_flags" to properly deal with errors during handle creation, although the vast majority of
programs can continue to use "guestfs_create" and not worry about this situation.
Out of memory errors are handled differently. The default action is to call abort(3). If this is
undesirable, then you can set a handler using "guestfs_set_out_of_memory_handler".
guestfs_last_error
const char *guestfs_last_error (guestfs_h *g);
This returns the last error message that happened on "g". If there has not been an error since the
handle was created, then this returns "NULL".
Note the returned string does not have a newline character at the end. Most error messages are single
lines. Some are split over multiple lines and contain "\n" characters within the string but not at the
end.
The lifetime of the returned string is until the next error occurs on the same handle, or "guestfs_close"
is called. If you need to keep it longer, copy it.
guestfs_last_errno
int guestfs_last_errno (guestfs_h *g);
This returns the last error number (errno) that happened on "g".
If successful, an errno integer not equal to zero is returned.
In many cases the special errno "ENOTSUP" is returned if you tried to call a function or use a feature
which is not supported.
If no error number is available, this returns 0. This call can return 0 in three situations:
1. There has not been any error on the handle.
2. There has been an error but the errno was meaningless. This corresponds to the case where the error
did not come from a failed system call, but for some other reason.
3. There was an error from a failed system call, but for some reason the errno was not captured and
returned. This usually indicates a bug in libguestfs.
Libguestfs tries to convert the errno from inside the applicance into a corresponding errno for the
caller (not entirely trivial: the appliance might be running a completely different operating system from
the library and error numbers are not standardized across Un*xen). If this could not be done, then the
error is translated to "EINVAL". In practice this should only happen in very rare circumstances.
guestfs_set_error_handler
typedef void (*guestfs_error_handler_cb) (guestfs_h *g,
void *opaque,
const char *msg);
void guestfs_set_error_handler (guestfs_h *g,
guestfs_error_handler_cb cb,
void *opaque);
The callback "cb" will be called if there is an error. The parameters passed to the callback are an
opaque data pointer and the error message string.
"errno" is not passed to the callback. To get that the callback must call "guestfs_last_errno".
Note that the message string "msg" is freed as soon as the callback function returns, so if you want to
stash it somewhere you must make your own copy.
The default handler prints messages on "stderr".
If you set "cb" to "NULL" then no handler is called.
guestfs_get_error_handler
guestfs_error_handler_cb guestfs_get_error_handler (guestfs_h *g,
void **opaque_rtn);
Returns the current error handler callback.
guestfs_push_error_handler
void guestfs_push_error_handler (guestfs_h *g,
guestfs_error_handler_cb cb,
void *opaque);
This is the same as "guestfs_set_error_handler", except that the old error handler is stashed away in a
stack inside the handle. You can restore the previous error handler by calling
"guestfs_pop_error_handler".
Use the following code to temporarily disable errors around a function:
guestfs_push_error_handler (g, NULL, NULL);
guestfs_mkdir (g, "/foo"); /* We don't care if this fails. */
guestfs_pop_error_handler (g);
guestfs_pop_error_handler
void guestfs_pop_error_handler (guestfs_h *g);
Restore the previous error handler (see "guestfs_push_error_handler").
If you pop the stack too many times, then the default error handler is restored.
guestfs_set_out_of_memory_handler
typedef void (*guestfs_abort_cb) (void);
void guestfs_set_out_of_memory_handler (guestfs_h *g,
guestfs_abort_cb);
The callback "cb" will be called if there is an out of memory situation. Note this callback must not
return.
The default is to call abort(3).
You cannot set "cb" to "NULL". You can't ignore out of memory situations.
guestfs_get_out_of_memory_handler
guestfs_abort_fn guestfs_get_out_of_memory_handler (guestfs_h *g);
This returns the current out of memory handler.
API CALLS
guestfs_acl_delete_def_file
int
guestfs_acl_delete_def_file (guestfs_h *g,
const char *dir);
This function deletes the default POSIX Access Control List (ACL) attached to directory "dir".
This function returns 0 on success or -1 on error.
(Added in 1.19.63)
guestfs_acl_get_file
char *
guestfs_acl_get_file (guestfs_h *g,
const char *path,
const char *acltype);
This function returns the POSIX Access Control List (ACL) attached to "path". The ACL is returned in
"long text form" (see acl(5)).
The "acltype" parameter may be:
"access"
Return the ordinary (access) ACL for any file, directory or other filesystem object.
"default"
Return the default ACL. Normally this only makes sense if "path" is a directory.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.63)
guestfs_acl_set_file
int
guestfs_acl_set_file (guestfs_h *g,
const char *path,
const char *acltype,
const char *acl);
This function sets the POSIX Access Control List (ACL) attached to "path".
The "acltype" parameter may be:
"access"
Set the ordinary (access) ACL for any file, directory or other filesystem object.
"default"
Set the default ACL. Normally this only makes sense if "path" is a directory.
The "acl" parameter is the new ACL in either "long text form" or "short text form" (see acl(5)). The new
ACL completely replaces any previous ACL on the file. The ACL must contain the full Unix permissions
(eg. "u::rwx,g::rx,o::rx").
If you are specifying individual users or groups, then the mask field is also required (eg. "m::rwx"),
followed by the "u:ID:..." and/or "g:ID:..." field(s). A full ACL string might therefore look like this:
u::rwx,g::rwx,o::rwx,m::rwx,u:500:rwx,g:500:rwx
\ Unix permissions / \mask/ \ ACL /
You should use numeric UIDs and GIDs. To map usernames and groupnames to the correct numeric ID in the
context of the guest, use the Augeas functions (see "guestfs_aug_init").
This function returns 0 on success or -1 on error.
(Added in 1.19.63)
guestfs_add_cdrom
int
guestfs_add_cdrom (guestfs_h *g,
const char *filename);
This function is deprecated. In new code, use the "guestfs_add_drive" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This function adds a virtual CD-ROM disk image to the guest.
Do not use this function! ISO files are just ordinary read-only disk images. Use "guestfs_add_drive_ro"
instead.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_add_domain
int
guestfs_add_domain (guestfs_h *g,
const char *dom,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_ADD_DOMAIN_LIBVIRTURI, const char *libvirturi,
GUESTFS_ADD_DOMAIN_READONLY, int readonly,
GUESTFS_ADD_DOMAIN_IFACE, const char *iface,
GUESTFS_ADD_DOMAIN_LIVE, int live,
GUESTFS_ADD_DOMAIN_ALLOWUUID, int allowuuid,
GUESTFS_ADD_DOMAIN_READONLYDISK, const char *readonlydisk,
This function adds the disk(s) attached to the named libvirt domain "dom". It works by connecting to
libvirt, requesting the domain and domain XML from libvirt, parsing it for disks, and calling
"guestfs_add_drive_opts" on each one.
The number of disks added is returned. This operation is atomic: if an error is returned, then no disks
are added.
This function does some minimal checks to make sure the libvirt domain is not running (unless "readonly"
is true). In a future version we will try to acquire the libvirt lock on each disk.
Disks must be accessible locally. This often means that adding disks from a remote libvirt connection
(see http://libvirt.org/remote.html) will fail unless those disks are accessible via the same device path
locally too.
The optional "libvirturi" parameter sets the libvirt URI (see http://libvirt.org/uri.html). If this is
not set then we connect to the default libvirt URI (or one set through an environment variable, see the
libvirt documentation for full details).
The optional "live" flag controls whether this call will try to connect to a running virtual machine
"guestfsd" process if it sees a suitable <channel> element in the libvirt XML definition. The default
(if the flag is omitted) is never to try. See "ATTACHING TO RUNNING DAEMONS" in guestfs(3) for more
information.
If the "allowuuid" flag is true (default is false) then a UUID may be passed instead of the domain name.
The "dom" string is treated as a UUID first and looked up, and if that lookup fails then we treat "dom"
as a name as usual.
The optional "readonlydisk" parameter controls what we do for disks which are marked <readonly/> in the
libvirt XML. Possible values are:
readonlydisk = "error"
If "readonly" is false:
The whole call is aborted with an error if any disk with the <readonly/> flag is found.
If "readonly" is true:
Disks with the <readonly/> flag are added read-only.
readonlydisk = "read"
If "readonly" is false:
Disks with the <readonly/> flag are added read-only. Other disks are added read/write.
If "readonly" is true:
Disks with the <readonly/> flag are added read-only.
readonlydisk = "write" (default)
If "readonly" is false:
Disks with the <readonly/> flag are added read/write.
If "readonly" is true:
Disks with the <readonly/> flag are added read-only.
readonlydisk = "ignore"
If "readonly" is true or false:
Disks with the <readonly/> flag are skipped.
The other optional parameters are passed directly through to "guestfs_add_drive_opts".
On error this function returns -1.
(Added in 1.7.4)
guestfs_add_domain_va
int
guestfs_add_domain_va (guestfs_h *g,
const char *dom,
va_list args);
This is the "va_list variant" of "guestfs_add_domain".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_domain_argv
int
guestfs_add_domain_argv (guestfs_h *g,
const char *dom,
const struct guestfs_add_domain_argv *optargs);
This is the "argv variant" of "guestfs_add_domain".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_drive
int
guestfs_add_drive (guestfs_h *g,
const char *filename);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_add_drive_opts" with no optional arguments.
(Added in 0.3)
guestfs_add_drive_opts
int
guestfs_add_drive_opts (guestfs_h *g,
const char *filename,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_ADD_DRIVE_OPTS_READONLY, int readonly,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, const char *format,
GUESTFS_ADD_DRIVE_OPTS_IFACE, const char *iface,
GUESTFS_ADD_DRIVE_OPTS_NAME, const char *name,
GUESTFS_ADD_DRIVE_OPTS_LABEL, const char *label,
GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, const char *protocol,
GUESTFS_ADD_DRIVE_OPTS_SERVER, char *const *server,
GUESTFS_ADD_DRIVE_OPTS_USERNAME, const char *username,
GUESTFS_ADD_DRIVE_OPTS_SECRET, const char *secret,
GUESTFS_ADD_DRIVE_OPTS_CACHEMODE, const char *cachemode,
This function adds a disk image called "filename" to the handle. "filename" may be a regular host file
or a host device.
When this function is called before "guestfs_launch" (the usual case) then the first time you call this
function, the disk appears in the API as "/dev/sda", the second time as "/dev/sdb", and so on.
In libguestfs ≥ 1.20 you can also call this function after launch (with some restrictions). This is
called "hotplugging". When hotplugging, you must specify a "label" so that the new disk gets a
predictable name. For more information see "HOTPLUGGING" in guestfs(3).
You don't necessarily need to be root when using libguestfs. However you obviously do need sufficient
permissions to access the filename for whatever operations you want to perform (ie. read access if you
just want to read the image or write access if you want to modify the image).
This call checks that "filename" exists.
"filename" may be the special string "/dev/null". See "NULL DISKS" in guestfs(3).
The optional arguments are:
"readonly"
If true then the image is treated as read-only. Writes are still allowed, but they are stored in a
temporary snapshot overlay which is discarded at the end. The disk that you add is not modified.
"format"
This forces the image format. If you omit this (or use "guestfs_add_drive" or
"guestfs_add_drive_ro") then the format is automatically detected. Possible formats include "raw"
and "qcow2".
Automatic detection of the format opens you up to a potential security hole when dealing with
untrusted raw-format images. See CVE-2010-3851 and RHBZ#642934. Specifying the format closes this
security hole.
"iface"
This rarely-used option lets you emulate the behaviour of the deprecated "guestfs_add_drive_with_if"
call (q.v.)
"name"
The name the drive had in the original guest, e.g. "/dev/sdb". This is used as a hint to the guest
inspection process if it is available.
"label"
Give the disk a label. The label should be a unique, short string using only ASCII characters
"[a-zA-Z]". As well as its usual name in the API (such as "/dev/sda"), the drive will also be named
"/dev/disk/guestfs/label".
See "DISK LABELS" in guestfs(3).
"protocol"
The optional protocol argument can be used to select an alternate source protocol.
See also: "REMOTE STORAGE" in guestfs(3).
"protocol = "file""
"filename" is interpreted as a local file or device. This is the default if the optional
protocol parameter is omitted.
"protocol = "ftp"|"ftps"|"http"|"https"|"tftp""
Connect to a remote FTP, HTTP or TFTP server. The "server" parameter must also be supplied - see
below.
See also: "FTP, HTTP AND TFTP" in guestfs(3)
"protocol = "gluster""
Connect to the GlusterFS server. The "server" parameter must also be supplied - see below.
See also: "GLUSTER" in guestfs(3)
"protocol = "iscsi""
Connect to the iSCSI server. The "server" parameter must also be supplied - see below.
See also: "ISCSI" in guestfs(3).
"protocol = "nbd""
Connect to the Network Block Device server. The "server" parameter must also be supplied - see
below.
See also: "NETWORK BLOCK DEVICE" in guestfs(3).
"protocol = "rbd""
Connect to the Ceph (librbd/RBD) server. The "server" parameter must also be supplied - see
below. The "username" parameter may be supplied. See below. The "secret" parameter may be
supplied. See below.
See also: "CEPH" in guestfs(3).
"protocol = "sheepdog""
Connect to the Sheepdog server. The "server" parameter may also be supplied - see below.
See also: "SHEEPDOG" in guestfs(3).
"protocol = "ssh""
Connect to the Secure Shell (ssh) server.
The "server" parameter must be supplied. The "username" parameter may be supplied. See below.
See also: "SSH" in guestfs(3).
"server"
For protocols which require access to a remote server, this is a list of server(s).
Protocol Number of servers required
-------- --------------------------
file List must be empty or param not used at all
ftp|ftps|http|https|tftp Exactly one
gluster Exactly one
iscsi Exactly one
nbd Exactly one
rbd One or more
sheepdog Zero or more
ssh Exactly one
Each list element is a string specifying a server. The string must be in one of the following
formats:
hostname
hostname:port
tcp:hostname
tcp:hostname:port
unix:/path/to/socket
If the port number is omitted, then the standard port number for the protocol is used (see
"/etc/services").
"username"
For the "ftp", "ftps", "http", "https", "iscsi", "rbd", "ssh" and "tftp" protocols, this specifies
the remote username.
If not given, then the local username is used for "ssh", and no authentication is attempted for ceph.
But note this sometimes may give unexpected results, for example if using the libvirt backend and if
the libvirt backend is configured to start the qemu appliance as a special user such as "qemu.qemu".
If in doubt, specify the remote username you want.
"secret"
For the "rbd" protocol only, this specifies the 'secret' to use when connecting to the remote device.
If not given, then a secret matching the given username will be looked up in the default keychain
locations, or if no username is given, then no authentication will be used.
"cachemode"
Choose whether or not libguestfs will obey sync operations (safe but slow) or not (unsafe but fast).
The possible values for this string are:
"cachemode = "writeback""
This is the default.
Write operations in the API do not return until a write(2) call has completed in the host [but
note this does not imply that anything gets written to disk].
Sync operations in the API, including implicit syncs caused by filesystem journalling, will not
return until an fdatasync(2) call has completed in the host, indicating that data has been
committed to disk.
"cachemode = "unsafe""
In this mode, there are no guarantees. Libguestfs may cache anything and ignore sync requests.
This is suitable only for scratch or temporary disks.
This function returns 0 on success or -1 on error.
(Added in 1.5.23)
guestfs_add_drive_opts_va
int
guestfs_add_drive_opts_va (guestfs_h *g,
const char *filename,
va_list args);
This is the "va_list variant" of "guestfs_add_drive_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_drive_opts_argv
int
guestfs_add_drive_opts_argv (guestfs_h *g,
const char *filename,
const struct guestfs_add_drive_opts_argv *optargs);
This is the "argv variant" of "guestfs_add_drive_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_drive_ro
int
guestfs_add_drive_ro (guestfs_h *g,
const char *filename);
This function is the equivalent of calling "guestfs_add_drive_opts" with the optional parameter
"GUESTFS_ADD_DRIVE_OPTS_READONLY" set to 1, so the disk is added read-only, with the format being
detected automatically.
This function returns 0 on success or -1 on error.
(Added in 1.0.38)
guestfs_add_drive_ro_with_if
int
guestfs_add_drive_ro_with_if (guestfs_h *g,
const char *filename,
const char *iface);
This function is deprecated. In new code, use the "guestfs_add_drive" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This is the same as "guestfs_add_drive_ro" but it allows you to specify the QEMU interface emulation to
use at run time.
This function returns 0 on success or -1 on error.
(Added in 1.0.84)
guestfs_add_drive_scratch
int
guestfs_add_drive_scratch (guestfs_h *g,
int64_t size,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_ADD_DRIVE_SCRATCH_NAME, const char *name,
GUESTFS_ADD_DRIVE_SCRATCH_LABEL, const char *label,
This command adds a temporary scratch drive to the handle. The "size" parameter is the virtual size (in
bytes). The scratch drive is blank initially (all reads return zeroes until you start writing to it).
The drive is deleted when the handle is closed.
The optional arguments "name" and "label" are passed through to "guestfs_add_drive".
This function returns 0 on success or -1 on error.
(Added in 1.23.10)
guestfs_add_drive_scratch_va
int
guestfs_add_drive_scratch_va (guestfs_h *g,
int64_t size,
va_list args);
This is the "va_list variant" of "guestfs_add_drive_scratch".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_drive_scratch_argv
int
guestfs_add_drive_scratch_argv (guestfs_h *g,
int64_t size,
const struct guestfs_add_drive_scratch_argv *optargs);
This is the "argv variant" of "guestfs_add_drive_scratch".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_drive_with_if
int
guestfs_add_drive_with_if (guestfs_h *g,
const char *filename,
const char *iface);
This function is deprecated. In new code, use the "guestfs_add_drive" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This is the same as "guestfs_add_drive" but it allows you to specify the QEMU interface emulation to use
at run time.
This function returns 0 on success or -1 on error.
(Added in 1.0.84)
guestfs_aug_clear
int
guestfs_aug_clear (guestfs_h *g,
const char *augpath);
Set the value associated with "path" to "NULL". This is the same as the augtool(1) "clear" command.
This function returns 0 on success or -1 on error.
(Added in 1.3.4)
guestfs_aug_close
int
guestfs_aug_close (guestfs_h *g);
Close the current Augeas handle and free up any resources used by it. After calling this, you have to
call "guestfs_aug_init" again before you can use any other Augeas functions.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_defnode
struct guestfs_int_bool *
guestfs_aug_defnode (guestfs_h *g,
const char *name,
const char *expr,
const char *val);
Defines a variable "name" whose value is the result of evaluating "expr".
If "expr" evaluates to an empty nodeset, a node is created, equivalent to calling "guestfs_aug_set"
"expr", "value". "name" will be the nodeset containing that single node.
On success this returns a pair containing the number of nodes in the nodeset, and a boolean flag if a
node was created.
This function returns a "struct guestfs_int_bool *", or NULL if there was an error. The caller must call
"guestfs_free_int_bool" after use.
(Added in 0.7)
guestfs_aug_defvar
int
guestfs_aug_defvar (guestfs_h *g,
const char *name,
const char *expr);
Defines an Augeas variable "name" whose value is the result of evaluating "expr". If "expr" is NULL,
then "name" is undefined.
On success this returns the number of nodes in "expr", or 0 if "expr" evaluates to something which is not
a nodeset.
On error this function returns -1.
(Added in 0.7)
guestfs_aug_get
char *
guestfs_aug_get (guestfs_h *g,
const char *augpath);
Look up the value associated with "path". If "path" matches exactly one node, the "value" is returned.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 0.7)
guestfs_aug_init
int
guestfs_aug_init (guestfs_h *g,
const char *root,
int flags);
Create a new Augeas handle for editing configuration files. If there was any previous Augeas handle
associated with this guestfs session, then it is closed.
You must call this before using any other "guestfs_aug_*" commands.
"root" is the filesystem root. "root" must not be NULL, use "/" instead.
The flags are the same as the flags defined in <augeas.h>, the logical or of the following integers:
"AUG_SAVE_BACKUP" = 1
Keep the original file with a ".augsave" extension.
"AUG_SAVE_NEWFILE" = 2
Save changes into a file with extension ".augnew", and do not overwrite original. Overrides
"AUG_SAVE_BACKUP".
"AUG_TYPE_CHECK" = 4
Typecheck lenses.
This option is only useful when debugging Augeas lenses. Use of this option may require additional
memory for the libguestfs appliance. You may need to set the "LIBGUESTFS_MEMSIZE" environment
variable or call "guestfs_set_memsize".
"AUG_NO_STDINC" = 8
Do not use standard load path for modules.
"AUG_SAVE_NOOP" = 16
Make save a no-op, just record what would have been changed.
"AUG_NO_LOAD" = 32
Do not load the tree in "guestfs_aug_init".
To close the handle, you can call "guestfs_aug_close".
To find out more about Augeas, see http://augeas.net/.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_insert
int
guestfs_aug_insert (guestfs_h *g,
const char *augpath,
const char *label,
int before);
Create a new sibling "label" for "path", inserting it into the tree before or after "path" (depending on
the boolean flag "before").
"path" must match exactly one existing node in the tree, and "label" must be a label, ie. not contain
"/", "*" or end with a bracketed index "[N]".
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_label
char *
guestfs_aug_label (guestfs_h *g,
const char *augpath);
The label (name of the last element) of the Augeas path expression "augpath" is returned. "augpath" must
match exactly one node, else this function returns an error.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.23.14)
guestfs_aug_load
int
guestfs_aug_load (guestfs_h *g);
Load files into the tree.
See "aug_load" in the Augeas documentation for the full gory details.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_ls
char **
guestfs_aug_ls (guestfs_h *g,
const char *augpath);
This is just a shortcut for listing "guestfs_aug_match" "path/*" and sorting the resulting nodes into
alphabetical order.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.8)
guestfs_aug_match
char **
guestfs_aug_match (guestfs_h *g,
const char *augpath);
Returns a list of paths which match the path expression "path". The returned paths are sufficiently
qualified so that they match exactly one node in the current tree.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.7)
guestfs_aug_mv
int
guestfs_aug_mv (guestfs_h *g,
const char *src,
const char *dest);
Move the node "src" to "dest". "src" must match exactly one node. "dest" is overwritten if it exists.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_rm
int
guestfs_aug_rm (guestfs_h *g,
const char *augpath);
Remove "path" and all of its children.
On success this returns the number of entries which were removed.
On error this function returns -1.
(Added in 0.7)
guestfs_aug_save
int
guestfs_aug_save (guestfs_h *g);
This writes all pending changes to disk.
The flags which were passed to "guestfs_aug_init" affect exactly how files are saved.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_set
int
guestfs_aug_set (guestfs_h *g,
const char *augpath,
const char *val);
Set the value associated with "path" to "val".
In the Augeas API, it is possible to clear a node by setting the value to NULL. Due to an oversight in
the libguestfs API you cannot do that with this call. Instead you must use the "guestfs_aug_clear" call.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_setm
int
guestfs_aug_setm (guestfs_h *g,
const char *base,
const char *sub,
const char *val);
Change multiple Augeas nodes in a single operation. "base" is an expression matching multiple nodes.
"sub" is a path expression relative to "base". All nodes matching "base" are found, and then for each
node, "sub" is changed to "val". "sub" may also be "NULL" in which case the "base" nodes are modified.
This returns the number of nodes modified.
On error this function returns -1.
(Added in 1.23.14)
guestfs_available
int
guestfs_available (guestfs_h *g,
char *const *groups);
This command is used to check the availability of some groups of functionality in the appliance, which
not all builds of the libguestfs appliance will be able to provide.
The libguestfs groups, and the functions that those groups correspond to, are listed in "AVAILABILITY" in
guestfs(3). You can also fetch this list at runtime by calling "guestfs_available_all_groups".
The argument "groups" is a list of group names, eg: "["inotify", "augeas"]" would check for the
availability of the Linux inotify functions and Augeas (configuration file editing) functions.
The command returns no error if all requested groups are available.
It fails with an error if one or more of the requested groups is unavailable in the appliance.
If an unknown group name is included in the list of groups then an error is always returned.
Notes:
• "guestfs_feature_available" is the same as this call, but with a slightly simpler to use API: that
call returns a boolean true/false instead of throwing an error.
• You must call "guestfs_launch" before calling this function.
The reason is because we don't know what groups are supported by the appliance/daemon until it is
running and can be queried.
• If a group of functions is available, this does not necessarily mean that they will work. You still
have to check for errors when calling individual API functions even if they are available.
• It is usually the job of distro packagers to build complete functionality into the libguestfs
appliance. Upstream libguestfs, if built from source with all requirements satisfied, will support
everything.
• This call was added in version 1.0.80. In previous versions of libguestfs all you could do would be
to speculatively execute a command to find out if the daemon implemented it. See also
"guestfs_version".
See also "guestfs_filesystem_available".
This function returns 0 on success or -1 on error.
(Added in 1.0.80)
guestfs_available_all_groups
char **
guestfs_available_all_groups (guestfs_h *g);
This command returns a list of all optional groups that this daemon knows about. Note this returns both
supported and unsupported groups. To find out which ones the daemon can actually support you have to
call "guestfs_available" / "guestfs_feature_available" on each member of the returned list.
See also "guestfs_available", "guestfs_feature_available" and "AVAILABILITY" in guestfs(3).
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.3.15)
guestfs_base64_in
int
guestfs_base64_in (guestfs_h *g,
const char *base64file,
const char *filename);
This command uploads base64-encoded data from "base64file" to "filename".
This function returns 0 on success or -1 on error.
(Added in 1.3.5)
guestfs_base64_out
int
guestfs_base64_out (guestfs_h *g,
const char *filename,
const char *base64file);
This command downloads the contents of "filename", writing it out to local file "base64file" encoded as
base64.
This function returns 0 on success or -1 on error.
(Added in 1.3.5)
guestfs_blkid
char **
guestfs_blkid (guestfs_h *g,
const char *device);
This command returns block device attributes for "device". The following fields are usually present in
the returned hash. Other fields may also be present.
"UUID"
The uuid of this device.
"LABEL"
The label of this device.
"VERSION"
The version of blkid command.
"TYPE"
The filesystem type or RAID of this device.
"USAGE"
The usage of this device, for example "filesystem" or "raid".
This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of
strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing
NULL entry. The caller must free the strings and the array after use.
(Added in 1.15.9)
guestfs_blockdev_flushbufs
int
guestfs_blockdev_flushbufs (guestfs_h *g,
const char *device);
This tells the kernel to flush internal buffers associated with "device".
This uses the blockdev(8) command.
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_getbsz
int
guestfs_blockdev_getbsz (guestfs_h *g,
const char *device);
This returns the block size of a device.
Note: this is different from both size in blocks and filesystem block size. Also this setting is not
really used by anything. You should probably not use it for anything. Filesystems have their own idea
about what block size to choose.
This uses the blockdev(8) command.
On error this function returns -1.
(Added in 0.9.3)
guestfs_blockdev_getro
int
guestfs_blockdev_getro (guestfs_h *g,
const char *device);
Returns a boolean indicating if the block device is read-only (true if read-only, false if not).
This uses the blockdev(8) command.
This function returns a C truth value on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_getsize64
int64_t
guestfs_blockdev_getsize64 (guestfs_h *g,
const char *device);
This returns the size of the device in bytes.
See also "guestfs_blockdev_getsz".
This uses the blockdev(8) command.
On error this function returns -1.
(Added in 0.9.3)
guestfs_blockdev_getss
int
guestfs_blockdev_getss (guestfs_h *g,
const char *device);
This returns the size of sectors on a block device. Usually 512, but can be larger for modern devices.
(Note, this is not the size in sectors, use "guestfs_blockdev_getsz" for that).
This uses the blockdev(8) command.
On error this function returns -1.
(Added in 0.9.3)
guestfs_blockdev_getsz
int64_t
guestfs_blockdev_getsz (guestfs_h *g,
const char *device);
This returns the size of the device in units of 512-byte sectors (even if the sectorsize isn't 512 bytes
... weird).
See also "guestfs_blockdev_getss" for the real sector size of the device, and
"guestfs_blockdev_getsize64" for the more useful size in bytes.
This uses the blockdev(8) command.
On error this function returns -1.
(Added in 0.9.3)
guestfs_blockdev_rereadpt
int
guestfs_blockdev_rereadpt (guestfs_h *g,
const char *device);
Reread the partition table on "device".
This uses the blockdev(8) command.
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_setbsz
int
guestfs_blockdev_setbsz (guestfs_h *g,
const char *device,
int blocksize);
This function is deprecated. In new code, use the "guestfs_mkfs" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This call does nothing and has never done anything because of a bug in blockdev. Do not use it.
If you need to set the filesystem block size, use the "blocksize" option of "guestfs_mkfs".
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_setro
int
guestfs_blockdev_setro (guestfs_h *g,
const char *device);
Sets the block device named "device" to read-only.
This uses the blockdev(8) command.
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_setrw
int
guestfs_blockdev_setrw (guestfs_h *g,
const char *device);
Sets the block device named "device" to read-write.
This uses the blockdev(8) command.
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_btrfs_device_add
int
guestfs_btrfs_device_add (guestfs_h *g,
char *const *devices,
const char *fs);
Add the list of device(s) in "devices" to the btrfs filesystem mounted at "fs". If "devices" is an empty
list, this does nothing.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_device_delete
int
guestfs_btrfs_device_delete (guestfs_h *g,
char *const *devices,
const char *fs);
Remove the "devices" from the btrfs filesystem mounted at "fs". If "devices" is an empty list, this does
nothing.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_filesystem_balance
int
guestfs_btrfs_filesystem_balance (guestfs_h *g,
const char *fs);
Balance the chunks in the btrfs filesystem mounted at "fs" across the underlying devices.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_filesystem_resize
int
guestfs_btrfs_filesystem_resize (guestfs_h *g,
const char *mountpoint,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_BTRFS_FILESYSTEM_RESIZE_SIZE, int64_t size,
This command resizes a btrfs filesystem.
Note that unlike other resize calls, the filesystem has to be mounted and the parameter is the mountpoint
not the device (this is a requirement of btrfs itself).
The optional parameters are:
"size"
The new size (in bytes) of the filesystem. If omitted, the filesystem is resized to the maximum
size.
See also btrfs(8).
This function returns 0 on success or -1 on error.
(Added in 1.11.17)
guestfs_btrfs_filesystem_resize_va
int
guestfs_btrfs_filesystem_resize_va (guestfs_h *g,
const char *mountpoint,
va_list args);
This is the "va_list variant" of "guestfs_btrfs_filesystem_resize".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_btrfs_filesystem_resize_argv
int
guestfs_btrfs_filesystem_resize_argv (guestfs_h *g,
const char *mountpoint,
const struct guestfs_btrfs_filesystem_resize_argv *optargs);
This is the "argv variant" of "guestfs_btrfs_filesystem_resize".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_btrfs_filesystem_sync
int
guestfs_btrfs_filesystem_sync (guestfs_h *g,
const char *fs);
Force sync on the btrfs filesystem mounted at "fs".
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_fsck
int
guestfs_btrfs_fsck (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_BTRFS_FSCK_SUPERBLOCK, int64_t superblock,
GUESTFS_BTRFS_FSCK_REPAIR, int repair,
Used to check a btrfs filesystem, "device" is the device file where the filesystem is stored.
This function returns 0 on success or -1 on error.
(Added in 1.17.43)
guestfs_btrfs_fsck_va
int
guestfs_btrfs_fsck_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_btrfs_fsck".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_btrfs_fsck_argv
int
guestfs_btrfs_fsck_argv (guestfs_h *g,
const char *device,
const struct guestfs_btrfs_fsck_argv *optargs);
This is the "argv variant" of "guestfs_btrfs_fsck".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_btrfs_set_seeding
int
guestfs_btrfs_set_seeding (guestfs_h *g,
const char *device,
int seeding);
Enable or disable the seeding feature of a device that contains a btrfs filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.17.43)
guestfs_btrfs_subvolume_create
int
guestfs_btrfs_subvolume_create (guestfs_h *g,
const char *dest);
Create a btrfs subvolume. The "dest" argument is the destination directory and the name of the snapshot,
in the form "/path/to/dest/name".
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_subvolume_delete
int
guestfs_btrfs_subvolume_delete (guestfs_h *g,
const char *subvolume);
Delete the named btrfs subvolume.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_subvolume_list
struct guestfs_btrfssubvolume_list *
guestfs_btrfs_subvolume_list (guestfs_h *g,
const char *fs);
List the btrfs snapshots and subvolumes of the btrfs filesystem which is mounted at "fs".
This function returns a "struct guestfs_btrfssubvolume_list *", or NULL if there was an error. The
caller must call "guestfs_free_btrfssubvolume_list" after use.
(Added in 1.17.35)
guestfs_btrfs_subvolume_set_default
int
guestfs_btrfs_subvolume_set_default (guestfs_h *g,
int64_t id,
const char *fs);
Set the subvolume of the btrfs filesystem "fs" which will be mounted by default. See
"guestfs_btrfs_subvolume_list" to get a list of subvolumes.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_subvolume_snapshot
int
guestfs_btrfs_subvolume_snapshot (guestfs_h *g,
const char *source,
const char *dest);
Create a writable snapshot of the btrfs subvolume "source". The "dest" argument is the destination
directory and the name of the snapshot, in the form "/path/to/dest/name".
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_canonical_device_name
char *
guestfs_canonical_device_name (guestfs_h *g,
const char *device);
This utility function is useful when displaying device names to the user. It takes a number of irregular
device names and returns them in a consistent format:
"/dev/hdX"
"/dev/vdX"
These are returned as "/dev/sdX". Note this works for device names and partition names. This is
approximately the reverse of the algorithm described in "BLOCK DEVICE NAMING" in guestfs(3).
"/dev/mapper/VG-LV"
"/dev/dm-N"
Converted to "/dev/VG/LV" form using "guestfs_lvm_canonical_lvm_name".
Other strings are returned unmodified.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.7)
guestfs_cap_get_file
char *
guestfs_cap_get_file (guestfs_h *g,
const char *path);
This function returns the Linux capabilities attached to "path". The capabilities set is returned in
text form (see cap_to_text(3)).
If no capabilities are attached to a file, an empty string is returned.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.63)
guestfs_cap_set_file
int
guestfs_cap_set_file (guestfs_h *g,
const char *path,
const char *cap);
This function sets the Linux capabilities attached to "path". The capabilities set "cap" should be
passed in text form (see cap_from_text(3)).
This function returns 0 on success or -1 on error.
(Added in 1.19.63)
guestfs_case_sensitive_path
char *
guestfs_case_sensitive_path (guestfs_h *g,
const char *path);
This can be used to resolve case insensitive paths on a filesystem which is case sensitive. The use case
is to resolve paths which you have read from Windows configuration files or the Windows Registry, to the
true path.
The command handles a peculiarity of the Linux ntfs-3g filesystem driver (and probably others), which is
that although the underlying filesystem is case-insensitive, the driver exports the filesystem to Linux
as case-sensitive.
One consequence of this is that special directories such as "c:\windows" may appear as "/WINDOWS" or
"/windows" (or other things) depending on the precise details of how they were created. In Windows
itself this would not be a problem.
Bug or feature? You decide: http://www.tuxera.com/community/ntfs-3g-faq/#posixfilenames1
"guestfs_case_sensitive_path" attempts to resolve the true case of each element in the path. It will
return a resolved path if either the full path or its parent directory exists. If the parent directory
exists but the full path does not, the case of the parent directory will be correctly resolved, and the
remainder appended unmodified. For example, if the file "/Windows/System32/netkvm.sys" exists:
"guestfs_case_sensitive_path" ("/windows/system32/netkvm.sys")
"Windows/System32/netkvm.sys"
"guestfs_case_sensitive_path" ("/windows/system32/NoSuchFile")
"Windows/System32/NoSuchFile"
"guestfs_case_sensitive_path" ("/windows/system33/netkvm.sys")
ERROR
Note: Because of the above behaviour, "guestfs_case_sensitive_path" cannot be used to check for the
existence of a file.
Note: This function does not handle drive names, backslashes etc.
See also "guestfs_realpath".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.75)
guestfs_cat
char *
guestfs_cat (guestfs_h *g,
const char *path);
Return the contents of the file named "path".
Because, in C, this function returns a "char *", there is no way to differentiate between a "\0"
character in a file and end of string. To handle binary files, use the "guestfs_read_file" or
"guestfs_download" functions.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 0.4)
guestfs_checksum
char *
guestfs_checksum (guestfs_h *g,
const char *csumtype,
const char *path);
This call computes the MD5, SHAx or CRC checksum of the file named "path".
The type of checksum to compute is given by the "csumtype" parameter which must have one of the following
values:
"crc"
Compute the cyclic redundancy check (CRC) specified by POSIX for the "cksum" command.
"md5"
Compute the MD5 hash (using the "md5sum" program).
"sha1"
Compute the SHA1 hash (using the "sha1sum" program).
"sha224"
Compute the SHA224 hash (using the "sha224sum" program).
"sha256"
Compute the SHA256 hash (using the "sha256sum" program).
"sha384"
Compute the SHA384 hash (using the "sha384sum" program).
"sha512"
Compute the SHA512 hash (using the "sha512sum" program).
The checksum is returned as a printable string.
To get the checksum for a device, use "guestfs_checksum_device".
To get the checksums for many files, use "guestfs_checksums_out".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.2)
guestfs_checksum_device
char *
guestfs_checksum_device (guestfs_h *g,
const char *csumtype,
const char *device);
This call computes the MD5, SHAx or CRC checksum of the contents of the device named "device". For the
types of checksums supported see the "guestfs_checksum" command.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.3.2)
guestfs_checksums_out
int
guestfs_checksums_out (guestfs_h *g,
const char *csumtype,
const char *directory,
const char *sumsfile);
This command computes the checksums of all regular files in "directory" and then emits a list of those
checksums to the local output file "sumsfile".
This can be used for verifying the integrity of a virtual machine. However to be properly secure you
should pay attention to the output of the checksum command (it uses the ones from GNU coreutils). In
particular when the filename is not printable, coreutils uses a special backslash syntax. For more
information, see the GNU coreutils info file.
This function returns 0 on success or -1 on error.
(Added in 1.3.7)
guestfs_chmod
int
guestfs_chmod (guestfs_h *g,
int mode,
const char *path);
Change the mode (permissions) of "path" to "mode". Only numeric modes are supported.
Note: When using this command from guestfish, "mode" by default would be decimal, unless you prefix it
with 0 to get octal, ie. use 0700 not 700.
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_chown
int
guestfs_chown (guestfs_h *g,
int owner,
int group,
const char *path);
Change the file owner to "owner" and group to "group".
Only numeric uid and gid are supported. If you want to use names, you will need to locate and parse the
password file yourself (Augeas support makes this relatively easy).
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_command
char *
guestfs_command (guestfs_h *g,
char *const *arguments);
This call runs a command from the guest filesystem. The filesystem must be mounted, and must contain a
compatible operating system (ie. something Linux, with the same or compatible processor architecture).
The single parameter is an argv-style list of arguments. The first element is the name of the program to
run. Subsequent elements are parameters. The list must be non-empty (ie. must contain a program name).
Note that the command runs directly, and is not invoked via the shell (see "guestfs_sh").
The return value is anything printed to stdout by the command.
If the command returns a non-zero exit status, then this function returns an error message. The error
message string is the content of stderr from the command.
The $PATH environment variable will contain at least "/usr/bin" and "/bin". If you require a program
from another location, you should provide the full path in the first parameter.
Shared libraries and data files required by the program must be available on filesystems which are
mounted in the correct places. It is the caller's responsibility to ensure all filesystems that are
needed are mounted at the right locations.
This function returns a string, or NULL on error. The caller must free the returned string after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 0.9.1)
guestfs_command_lines
char **
guestfs_command_lines (guestfs_h *g,
char *const *arguments);
This is the same as "guestfs_command", but splits the result into a list of lines.
See also: "guestfs_sh_lines"
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 0.9.1)
guestfs_compress_device_out
int
guestfs_compress_device_out (guestfs_h *g,
const char *ctype,
const char *device,
const char *zdevice,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COMPRESS_DEVICE_OUT_LEVEL, int level,
This command compresses "device" and writes it out to the local file "zdevice".
The "ctype" and optional "level" parameters have the same meaning as in "guestfs_compress_out".
This function returns 0 on success or -1 on error.
(Added in 1.13.15)
guestfs_compress_device_out_va
int
guestfs_compress_device_out_va (guestfs_h *g,
const char *ctype,
const char *device,
const char *zdevice,
va_list args);
This is the "va_list variant" of "guestfs_compress_device_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_compress_device_out_argv
int
guestfs_compress_device_out_argv (guestfs_h *g,
const char *ctype,
const char *device,
const char *zdevice,
const struct guestfs_compress_device_out_argv *optargs);
This is the "argv variant" of "guestfs_compress_device_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_compress_out
int
guestfs_compress_out (guestfs_h *g,
const char *ctype,
const char *file,
const char *zfile,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COMPRESS_OUT_LEVEL, int level,
This command compresses "file" and writes it out to the local file "zfile".
The compression program used is controlled by the "ctype" parameter. Currently this includes:
"compress", "gzip", "bzip2", "xz" or "lzop". Some compression types may not be supported by particular
builds of libguestfs, in which case you will get an error containing the substring "not supported".
The optional "level" parameter controls compression level. The meaning and default for this parameter
depends on the compression program being used.
This function returns 0 on success or -1 on error.
(Added in 1.13.15)
guestfs_compress_out_va
int
guestfs_compress_out_va (guestfs_h *g,
const char *ctype,
const char *file,
const char *zfile,
va_list args);
This is the "va_list variant" of "guestfs_compress_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_compress_out_argv
int
guestfs_compress_out_argv (guestfs_h *g,
const char *ctype,
const char *file,
const char *zfile,
const struct guestfs_compress_out_argv *optargs);
This is the "argv variant" of "guestfs_compress_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_config
int
guestfs_config (guestfs_h *g,
const char *hvparam,
const char *hvvalue);
This can be used to add arbitrary hypervisor parameters of the form -param value. Actually it's not
quite arbitrary - we prevent you from setting some parameters which would interfere with parameters that
we use.
The first character of "hvparam" string must be a "-" (dash).
"hvvalue" can be NULL.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_copy_device_to_device
int
guestfs_copy_device_to_device (guestfs_h *g,
const char *src,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COPY_DEVICE_TO_DEVICE_SRCOFFSET, int64_t srcoffset,
GUESTFS_COPY_DEVICE_TO_DEVICE_DESTOFFSET, int64_t destoffset,
GUESTFS_COPY_DEVICE_TO_DEVICE_SIZE, int64_t size,
GUESTFS_COPY_DEVICE_TO_DEVICE_SPARSE, int sparse,
The four calls "guestfs_copy_device_to_device", "guestfs_copy_device_to_file",
"guestfs_copy_file_to_device", and "guestfs_copy_file_to_file" let you copy from a source (device|file)
to a destination (device|file).
Partial copies can be made since you can specify optionally the source offset, destination offset and
size to copy. These values are all specified in bytes. If not given, the offsets both default to zero,
and the size defaults to copying as much as possible until we hit the end of the source.
The source and destination may be the same object. However overlapping regions may not be copied
correctly.
If the destination is a file, it is created if required. If the destination file is not large enough, it
is extended.
If the "sparse" flag is true then the call avoids writing blocks that contain only zeroes, which can help
in some situations where the backing disk is thin-provisioned. Note that unless the target is already
zeroed, using this option will result in incorrect copying.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.13.25)
guestfs_copy_device_to_device_va
int
guestfs_copy_device_to_device_va (guestfs_h *g,
const char *src,
const char *dest,
va_list args);
This is the "va_list variant" of "guestfs_copy_device_to_device".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_device_to_device_argv
int
guestfs_copy_device_to_device_argv (guestfs_h *g,
const char *src,
const char *dest,
const struct guestfs_copy_device_to_device_argv *optargs);
This is the "argv variant" of "guestfs_copy_device_to_device".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_device_to_file
int
guestfs_copy_device_to_file (guestfs_h *g,
const char *src,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COPY_DEVICE_TO_FILE_SRCOFFSET, int64_t srcoffset,
GUESTFS_COPY_DEVICE_TO_FILE_DESTOFFSET, int64_t destoffset,
GUESTFS_COPY_DEVICE_TO_FILE_SIZE, int64_t size,
GUESTFS_COPY_DEVICE_TO_FILE_SPARSE, int sparse,
See "guestfs_copy_device_to_device" for a general overview of this call.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.13.25)
guestfs_copy_device_to_file_va
int
guestfs_copy_device_to_file_va (guestfs_h *g,
const char *src,
const char *dest,
va_list args);
This is the "va_list variant" of "guestfs_copy_device_to_file".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_device_to_file_argv
int
guestfs_copy_device_to_file_argv (guestfs_h *g,
const char *src,
const char *dest,
const struct guestfs_copy_device_to_file_argv *optargs);
This is the "argv variant" of "guestfs_copy_device_to_file".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_file_to_device
int
guestfs_copy_file_to_device (guestfs_h *g,
const char *src,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COPY_FILE_TO_DEVICE_SRCOFFSET, int64_t srcoffset,
GUESTFS_COPY_FILE_TO_DEVICE_DESTOFFSET, int64_t destoffset,
GUESTFS_COPY_FILE_TO_DEVICE_SIZE, int64_t size,
GUESTFS_COPY_FILE_TO_DEVICE_SPARSE, int sparse,
See "guestfs_copy_device_to_device" for a general overview of this call.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.13.25)
guestfs_copy_file_to_device_va
int
guestfs_copy_file_to_device_va (guestfs_h *g,
const char *src,
const char *dest,
va_list args);
This is the "va_list variant" of "guestfs_copy_file_to_device".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_file_to_device_argv
int
guestfs_copy_file_to_device_argv (guestfs_h *g,
const char *src,
const char *dest,
const struct guestfs_copy_file_to_device_argv *optargs);
This is the "argv variant" of "guestfs_copy_file_to_device".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_file_to_file
int
guestfs_copy_file_to_file (guestfs_h *g,
const char *src,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COPY_FILE_TO_FILE_SRCOFFSET, int64_t srcoffset,
GUESTFS_COPY_FILE_TO_FILE_DESTOFFSET, int64_t destoffset,
GUESTFS_COPY_FILE_TO_FILE_SIZE, int64_t size,
GUESTFS_COPY_FILE_TO_FILE_SPARSE, int sparse,
See "guestfs_copy_device_to_device" for a general overview of this call.
This is not the function you want for copying files. This is for copying blocks within existing files.
See "guestfs_cp", "guestfs_cp_a" and "guestfs_mv" for general file copying and moving functions.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.13.25)
guestfs_copy_file_to_file_va
int
guestfs_copy_file_to_file_va (guestfs_h *g,
const char *src,
const char *dest,
va_list args);
This is the "va_list variant" of "guestfs_copy_file_to_file".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_file_to_file_argv
int
guestfs_copy_file_to_file_argv (guestfs_h *g,
const char *src,
const char *dest,
const struct guestfs_copy_file_to_file_argv *optargs);
This is the "argv variant" of "guestfs_copy_file_to_file".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_size
int
guestfs_copy_size (guestfs_h *g,
const char *src,
const char *dest,
int64_t size);
This function is deprecated. In new code, use the "guestfs_copy_device_to_device" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This command copies exactly "size" bytes from one source device or file "src" to another destination
device or file "dest".
Note this will fail if the source is too short or if the destination is not large enough.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.0.87)
guestfs_cp
int
guestfs_cp (guestfs_h *g,
const char *src,
const char *dest);
This copies a file from "src" to "dest" where "dest" is either a destination filename or destination
directory.
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_cp_a
int
guestfs_cp_a (guestfs_h *g,
const char *src,
const char *dest);
This copies a file or directory from "src" to "dest" recursively using the "cp -a" command.
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_cp_r
int
guestfs_cp_r (guestfs_h *g,
const char *src,
const char *dest);
This copies a file or directory from "src" to "dest" recursively using the "cp -rP" command.
Most users should use "guestfs_cp_a" instead. This command is useful when you don't want to preserve
permissions, because the target filesystem does not support it (primarily when writing to DOS FAT
filesystems).
This function returns 0 on success or -1 on error.
(Added in 1.21.38)
guestfs_dd
int
guestfs_dd (guestfs_h *g,
const char *src,
const char *dest);
This function is deprecated. In new code, use the "guestfs_copy_device_to_device" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This command copies from one source device or file "src" to another destination device or file "dest".
Normally you would use this to copy to or from a device or partition, for example to duplicate a
filesystem.
If the destination is a device, it must be as large or larger than the source file or device, otherwise
the copy will fail. This command cannot do partial copies (see "guestfs_copy_device_to_device").
This function returns 0 on success or -1 on error.
(Added in 1.0.80)
guestfs_device_index
int
guestfs_device_index (guestfs_h *g,
const char *device);
This function takes a device name (eg. "/dev/sdb") and returns the index of the device in the list of
devices.
Index numbers start from 0. The named device must exist, for example as a string returned from
"guestfs_list_devices".
See also "guestfs_list_devices", "guestfs_part_to_dev".
On error this function returns -1.
(Added in 1.19.7)
guestfs_df
char *
guestfs_df (guestfs_h *g);
This command runs the "df" command to report disk space used.
This command is mostly useful for interactive sessions. It is not intended that you try to parse the
output string. Use "guestfs_statvfs" from programs.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.54)
guestfs_df_h
char *
guestfs_df_h (guestfs_h *g);
This command runs the "df -h" command to report disk space used in human-readable format.
This command is mostly useful for interactive sessions. It is not intended that you try to parse the
output string. Use "guestfs_statvfs" from programs.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.54)
guestfs_disk_format
char *
guestfs_disk_format (guestfs_h *g,
const char *filename);
Detect and return the format of the disk image called "filename". "filename" can also be a host device,
etc. If the format of the image could not be detected, then "unknown" is returned.
Note that detecting the disk format can be insecure under some circumstances. See "CVE-2010-3851" in
guestfs(3).
See also: "DISK IMAGE FORMATS" in guestfs(3)
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.38)
guestfs_disk_has_backing_file
int
guestfs_disk_has_backing_file (guestfs_h *g,
const char *filename);
Detect and return whether the disk image "filename" has a backing file.
Note that detecting disk features can be insecure under some circumstances. See "CVE-2010-3851" in
guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.19.39)
guestfs_disk_virtual_size
int64_t
guestfs_disk_virtual_size (guestfs_h *g,
const char *filename);
Detect and return the virtual size in bytes of the disk image called "filename".
Note that detecting disk features can be insecure under some circumstances. See "CVE-2010-3851" in
guestfs(3).
On error this function returns -1.
(Added in 1.19.39)
guestfs_dmesg
char *
guestfs_dmesg (guestfs_h *g);
This returns the kernel messages ("dmesg" output) from the guest kernel. This is sometimes useful for
extended debugging of problems.
Another way to get the same information is to enable verbose messages with "guestfs_set_verbose" or by
setting the environment variable "LIBGUESTFS_DEBUG=1" before running the program.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.18)
guestfs_download
int
guestfs_download (guestfs_h *g,
const char *remotefilename,
const char *filename);
Download file "remotefilename" and save it as "filename" on the local machine.
"filename" can also be a named pipe.
See also "guestfs_upload", "guestfs_cat".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.0.2)
guestfs_download_offset
int
guestfs_download_offset (guestfs_h *g,
const char *remotefilename,
const char *filename,
int64_t offset,
int64_t size);
Download file "remotefilename" and save it as "filename" on the local machine.
"remotefilename" is read for "size" bytes starting at "offset" (this region must be within the file or
device).
Note that there is no limit on the amount of data that can be downloaded with this call, unlike with
"guestfs_pread", and this call always reads the full amount unless an error occurs.
See also "guestfs_download", "guestfs_pread".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.5.17)
guestfs_drop_caches
int
guestfs_drop_caches (guestfs_h *g,
int whattodrop);
This instructs the guest kernel to drop its page cache, and/or dentries and inode caches. The parameter
"whattodrop" tells the kernel what precisely to drop, see http://linux-mm.org/Drop_Caches
Setting "whattodrop" to 3 should drop everything.
This automatically calls sync(2) before the operation, so that the maximum guest memory is freed.
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_du
int64_t
guestfs_du (guestfs_h *g,
const char *path);
This command runs the "du -s" command to estimate file space usage for "path".
"path" can be a file or a directory. If "path" is a directory then the estimate includes the contents of
the directory and all subdirectories (recursively).
The result is the estimated size in kilobytes (ie. units of 1024 bytes).
On error this function returns -1.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.0.54)
guestfs_e2fsck
int
guestfs_e2fsck (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_E2FSCK_CORRECT, int correct,
GUESTFS_E2FSCK_FORCEALL, int forceall,
This runs the ext2/ext3 filesystem checker on "device". It can take the following optional arguments:
"correct"
Automatically repair the file system. This option will cause e2fsck to automatically fix any
filesystem problems that can be safely fixed without human intervention.
This option may not be specified at the same time as the "forceall" option.
"forceall"
Assume an answer of 'yes' to all questions; allows e2fsck to be used non-interactively.
This option may not be specified at the same time as the "correct" option.
This function returns 0 on success or -1 on error.
(Added in 1.15.17)
guestfs_e2fsck_va
int
guestfs_e2fsck_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_e2fsck".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_e2fsck_argv
int
guestfs_e2fsck_argv (guestfs_h *g,
const char *device,
const struct guestfs_e2fsck_argv *optargs);
This is the "argv variant" of "guestfs_e2fsck".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_e2fsck_f
int
guestfs_e2fsck_f (guestfs_h *g,
const char *device);
This function is deprecated. In new code, use the "guestfs_e2fsck" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This runs "e2fsck -p -f device", ie. runs the ext2/ext3 filesystem checker on "device", noninteractively
(-p), even if the filesystem appears to be clean (-f).
This function returns 0 on success or -1 on error.
(Added in 1.0.29)
guestfs_echo_daemon
char *
guestfs_echo_daemon (guestfs_h *g,
char *const *words);
This command concatenates the list of "words" passed with single spaces between them and returns the
resulting string.
You can use this command to test the connection through to the daemon.
See also "guestfs_ping_daemon".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.69)
guestfs_egrep
char **
guestfs_egrep (guestfs_h *g,
const char *regex,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "egrep" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_egrepi
char **
guestfs_egrepi (guestfs_h *g,
const char *regex,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "egrep -i" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_equal
int
guestfs_equal (guestfs_h *g,
const char *file1,
const char *file2);
This compares the two files "file1" and "file2" and returns true if their content is exactly equal, or
false otherwise.
The external cmp(1) program is used for the comparison.
This function returns a C truth value on success or -1 on error.
(Added in 1.0.18)
guestfs_exists
int
guestfs_exists (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a file, directory (or anything) with the given "path" name.
See also "guestfs_is_file", "guestfs_is_dir", "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 0.8)
guestfs_extlinux
int
guestfs_extlinux (guestfs_h *g,
const char *directory);
Install the SYSLINUX bootloader on the device mounted at "directory". Unlike "guestfs_syslinux" which
requires a FAT filesystem, this can be used on an ext2/3/4 or btrfs filesystem.
The "directory" parameter can be either a mountpoint, or a directory within the mountpoint.
You also have to mark the partition as "active" ("guestfs_part_set_bootable") and a Master Boot Record
must be installed (eg. using "guestfs_pwrite_device") on the first sector of the whole disk. The
SYSLINUX package comes with some suitable Master Boot Records. See the extlinux(1) man page for further
information.
Additional configuration can be supplied to SYSLINUX by placing a file called "extlinux.conf" on the
filesystem under "directory". For further information about the contents of this file, see extlinux(1).
See also "guestfs_syslinux".
This function returns 0 on success or -1 on error.
(Added in 1.21.27)
guestfs_fallocate
int
guestfs_fallocate (guestfs_h *g,
const char *path,
int len);
This function is deprecated. In new code, use the "guestfs_fallocate64" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This command preallocates a file (containing zero bytes) named "path" of size "len" bytes. If the file
exists already, it is overwritten.
Do not confuse this with the guestfish-specific "alloc" command which allocates a file in the host and
attaches it as a device.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_fallocate64
int
guestfs_fallocate64 (guestfs_h *g,
const char *path,
int64_t len);
This command preallocates a file (containing zero bytes) named "path" of size "len" bytes. If the file
exists already, it is overwritten.
Note that this call allocates disk blocks for the file. To create a sparse file use
"guestfs_truncate_size" instead.
The deprecated call "guestfs_fallocate" does the same, but owing to an oversight it only allowed 30 bit
lengths to be specified, effectively limiting the maximum size of files created through that call to 1GB.
Do not confuse this with the guestfish-specific "alloc" and "sparse" commands which create a file in the
host and attach it as a device.
This function returns 0 on success or -1 on error.
(Added in 1.3.17)
guestfs_feature_available
int
guestfs_feature_available (guestfs_h *g,
char *const *groups);
This is the same as "guestfs_available", but unlike that call it returns a simple true/false boolean
result, instead of throwing an exception if a feature is not found. For other documentation see
"guestfs_available".
This function returns a C truth value on success or -1 on error.
(Added in 1.21.26)
guestfs_fgrep
char **
guestfs_fgrep (guestfs_h *g,
const char *pattern,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "fgrep" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_fgrepi
char **
guestfs_fgrepi (guestfs_h *g,
const char *pattern,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "fgrep -i" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_file
char *
guestfs_file (guestfs_h *g,
const char *path);
This call uses the standard file(1) command to determine the type or contents of the file.
This call will also transparently look inside various types of compressed file.
The exact command which runs is "file -zb path". Note in particular that the filename is not prepended
to the output (the -b option).
The output depends on the output of the underlying file(1) command and it can change in future in ways
beyond our control. In other words, the output is not guaranteed by the ABI.
See also: file(1), "guestfs_vfs_type", "guestfs_lstat", "guestfs_is_file", "guestfs_is_blockdev" (etc),
"guestfs_is_zero".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 0.9.1)
guestfs_file_architecture
char *
guestfs_file_architecture (guestfs_h *g,
const char *filename);
This detects the architecture of the binary "filename", and returns it if known.
Currently defined architectures are:
"i386"
This string is returned for all 32 bit i386, i486, i586, i686 binaries irrespective of the precise
processor requirements of the binary.
"x86_64"
64 bit x86-64.
"sparc"
32 bit SPARC.
"sparc64"
64 bit SPARC V9 and above.
"ia64"
Intel Itanium.
"ppc"
32 bit Power PC.
"ppc64"
64 bit Power PC.
Libguestfs may return other architecture strings in future.
The function works on at least the following types of files:
• many types of Un*x and Linux binary
• many types of Un*x and Linux shared library
• Windows Win32 and Win64 binaries
• Windows Win32 and Win64 DLLs
Win32 binaries and DLLs return "i386".
Win64 binaries and DLLs return "x86_64".
• Linux kernel modules
• Linux new-style initrd images
• some non-x86 Linux vmlinuz kernels
What it can't do currently:
• static libraries (libfoo.a)
• Linux old-style initrd as compressed ext2 filesystem (RHEL 3)
• x86 Linux vmlinuz kernels
x86 vmlinuz images (bzImage format) consist of a mix of 16-, 32- and compressed code, and are
horribly hard to unpack. If you want to find the architecture of a kernel, use the architecture of
the associated initrd or kernel module(s) instead.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.3)
guestfs_filesize
int64_t
guestfs_filesize (guestfs_h *g,
const char *file);
This command returns the size of "file" in bytes.
To get other stats about a file, use "guestfs_stat", "guestfs_lstat", "guestfs_is_dir", "guestfs_is_file"
etc. To get the size of block devices, use "guestfs_blockdev_getsize64".
On error this function returns -1.
(Added in 1.0.82)
guestfs_filesystem_available
int
guestfs_filesystem_available (guestfs_h *g,
const char *filesystem);
Check whether libguestfs supports the named filesystem. The argument "filesystem" is a filesystem name,
such as "ext3".
You must call "guestfs_launch" before using this command.
This is mainly useful as a negative test. If this returns true, it doesn't mean that a particular
filesystem can be created or mounted, since filesystems can fail for other reasons such as it being a
later version of the filesystem, or having incompatible features, or lacking the right mkfs.<fs> tool.
See also "guestfs_available", "guestfs_feature_available", "AVAILABILITY" in guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.19.5)
guestfs_fill
int
guestfs_fill (guestfs_h *g,
int c,
int len,
const char *path);
This command creates a new file called "path". The initial content of the file is "len" octets of "c",
where "c" must be a number in the range "[0..255]".
To fill a file with zero bytes (sparsely), it is much more efficient to use "guestfs_truncate_size". To
create a file with a pattern of repeating bytes use "guestfs_fill_pattern".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.0.79)
guestfs_fill_dir
int
guestfs_fill_dir (guestfs_h *g,
const char *dir,
int nr);
This function, useful for testing filesystems, creates "nr" empty files in the directory "dir" with names
00000000 through "nr-1" (ie. each file name is 8 digits long padded with zeroes).
This function returns 0 on success or -1 on error.
(Added in 1.19.32)
guestfs_fill_pattern
int
guestfs_fill_pattern (guestfs_h *g,
const char *pattern,
int len,
const char *path);
This function is like "guestfs_fill" except that it creates a new file of length "len" containing the
repeating pattern of bytes in "pattern". The pattern is truncated if necessary to ensure the length of
the file is exactly "len" bytes.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.3.12)
guestfs_find
char **
guestfs_find (guestfs_h *g,
const char *directory);
This command lists out all files and directories, recursively, starting at "directory". It is
essentially equivalent to running the shell command "find directory -print" but some post-processing
happens on the output, described below.
This returns a list of strings without any prefix. Thus if the directory structure was:
/tmp/a
/tmp/b
/tmp/c/d
then the returned list from "guestfs_find" "/tmp" would be 4 elements:
a
b
c
c/d
If "directory" is not a directory, then this command returns an error.
The returned list is sorted.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.0.27)
guestfs_find0
int
guestfs_find0 (guestfs_h *g,
const char *directory,
const char *files);
This command lists out all files and directories, recursively, starting at "directory", placing the
resulting list in the external file called "files".
This command works the same way as "guestfs_find" with the following exceptions:
• The resulting list is written to an external file.
• Items (filenames) in the result are separated by "\0" characters. See find(1) option -print0.
• The result list is not sorted.
This function returns 0 on success or -1 on error.
(Added in 1.0.74)
guestfs_findfs_label
char *
guestfs_findfs_label (guestfs_h *g,
const char *label);
This command searches the filesystems and returns the one which has the given label. An error is
returned if no such filesystem can be found.
To find the label of a filesystem, use "guestfs_vfs_label".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.3)
guestfs_findfs_uuid
char *
guestfs_findfs_uuid (guestfs_h *g,
const char *uuid);
This command searches the filesystems and returns the one which has the given UUID. An error is returned
if no such filesystem can be found.
To find the UUID of a filesystem, use "guestfs_vfs_uuid".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.3)
guestfs_fsck
int
guestfs_fsck (guestfs_h *g,
const char *fstype,
const char *device);
This runs the filesystem checker (fsck) on "device" which should have filesystem type "fstype".
The returned integer is the status. See fsck(8) for the list of status codes from "fsck".
Notes:
• Multiple status codes can be summed together.
• A non-zero return code can mean "success", for example if errors have been corrected on the
filesystem.
• Checking or repairing NTFS volumes is not supported (by linux-ntfs).
This command is entirely equivalent to running "fsck -a -t fstype device".
On error this function returns -1.
(Added in 1.0.16)
guestfs_fstrim
int
guestfs_fstrim (guestfs_h *g,
const char *mountpoint,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_FSTRIM_OFFSET, int64_t offset,
GUESTFS_FSTRIM_LENGTH, int64_t length,
GUESTFS_FSTRIM_MINIMUMFREEEXTENT, int64_t minimumfreeextent,
Trim the free space in the filesystem mounted on "mountpoint". The filesystem must be mounted read-
write.
The filesystem contents are not affected, but any free space in the filesystem is "trimmed", that is,
given back to the host device, thus making disk images more sparse, allowing unused space in qcow2 files
to be reused, etc.
This operation requires support in libguestfs, the mounted filesystem, the host filesystem, qemu and the
host kernel. If this support isn't present it may give an error or even appear to run but do nothing.
See also "guestfs_zero_free_space". That is a slightly different operation that turns free space in the
filesystem into zeroes. It is valid to call "guestfs_fstrim" either instead of, or after calling
"guestfs_zero_free_space".
This function returns 0 on success or -1 on error.
(Added in 1.19.6)
guestfs_fstrim_va
int
guestfs_fstrim_va (guestfs_h *g,
const char *mountpoint,
va_list args);
This is the "va_list variant" of "guestfs_fstrim".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_fstrim_argv
int
guestfs_fstrim_argv (guestfs_h *g,
const char *mountpoint,
const struct guestfs_fstrim_argv *optargs);
This is the "argv variant" of "guestfs_fstrim".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_get_append
const char *
guestfs_get_append (guestfs_h *g);
Return the additional kernel options which are added to the guest kernel command line.
If "NULL" then no options are added.
This function returns a string which may be NULL. There is no way to return an error from this function.
The string is owned by the guest handle and must not be freed.
(Added in 1.0.26)
guestfs_get_attach_method
char *
guestfs_get_attach_method (guestfs_h *g);
This function is deprecated. In new code, use the "guestfs_get_backend" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
Return the current backend.
See "guestfs_set_backend" and "BACKEND" in guestfs(3).
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.9.8)
guestfs_get_autosync
int
guestfs_get_autosync (guestfs_h *g);
Get the autosync flag.
This function returns a C truth value on success or -1 on error.
(Added in 0.3)
guestfs_get_backend
char *
guestfs_get_backend (guestfs_h *g);
Return the current backend.
This handle property was previously called the "attach method".
See "guestfs_set_backend" and "BACKEND" in guestfs(3).
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.21.26)
guestfs_get_cachedir
char *
guestfs_get_cachedir (guestfs_h *g);
Get the directory used by the handle to store the appliance cache.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.58)
guestfs_get_direct
int
guestfs_get_direct (guestfs_h *g);
Return the direct appliance mode flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.0.72)
guestfs_get_e2attrs
char *
guestfs_get_e2attrs (guestfs_h *g,
const char *file);
This returns the file attributes associated with "file".
The attributes are a set of bits associated with each inode which affect the behaviour of the file. The
attributes are returned as a string of letters (described below). The string may be empty, indicating
that no file attributes are set for this file.
These attributes are only present when the file is located on an ext2/3/4 filesystem. Using this call on
other filesystem types will result in an error.
The characters (file attributes) in the returned string are currently:
'A' When the file is accessed, its atime is not modified.
'a' The file is append-only.
'c' The file is compressed on-disk.
'D' (Directories only.) Changes to this directory are written synchronously to disk.
'd' The file is not a candidate for backup (see dump(8)).
'E' The file has compression errors.
'e' The file is using extents.
'h' The file is storing its blocks in units of the filesystem blocksize instead of sectors.
'I' (Directories only.) The directory is using hashed trees.
'i' The file is immutable. It cannot be modified, deleted or renamed. No link can be created to this
file.
'j' The file is data-journaled.
's' When the file is deleted, all its blocks will be zeroed.
'S' Changes to this file are written synchronously to disk.
'T' (Directories only.) This is a hint to the block allocator that subdirectories contained in this
directory should be spread across blocks. If not present, the block allocator will try to group
subdirectories together.
't' For a file, this disables tail-merging. (Not used by upstream implementations of ext2.)
'u' When the file is deleted, its blocks will be saved, allowing the file to be undeleted.
'X' The raw contents of the compressed file may be accessed.
'Z' The compressed file is dirty.
More file attributes may be added to this list later. Not all file attributes may be set for all kinds
of files. For detailed information, consult the chattr(1) man page.
See also "guestfs_set_e2attrs".
Don't confuse these attributes with extended attributes (see "guestfs_getxattr").
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.17.31)
guestfs_get_e2generation
int64_t
guestfs_get_e2generation (guestfs_h *g,
const char *file);
This returns the ext2 file generation of a file. The generation (which used to be called the "version")
is a number associated with an inode. This is most commonly used by NFS servers.
The generation is only present when the file is located on an ext2/3/4 filesystem. Using this call on
other filesystem types will result in an error.
See "guestfs_set_e2generation".
On error this function returns -1.
(Added in 1.17.31)
guestfs_get_e2label
char *
guestfs_get_e2label (guestfs_h *g,
const char *device);
This function is deprecated. In new code, use the "guestfs_vfs_label" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This returns the ext2/3/4 filesystem label of the filesystem on "device".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.15)
guestfs_get_e2uuid
char *
guestfs_get_e2uuid (guestfs_h *g,
const char *device);
This function is deprecated. In new code, use the "guestfs_vfs_uuid" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This returns the ext2/3/4 filesystem UUID of the filesystem on "device".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.15)
guestfs_get_hv
char *
guestfs_get_hv (guestfs_h *g);
Return the current hypervisor binary.
This is always non-NULL. If it wasn't set already, then this will return the default qemu binary name.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.23.17)
guestfs_get_libvirt_requested_credential_challenge
char *
guestfs_get_libvirt_requested_credential_challenge (guestfs_h *g,
int index);
Get the challenge (provided by libvirt) for the "index"'th requested credential. If libvirt did not
provide a challenge, this returns the empty string "".
See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.52)
guestfs_get_libvirt_requested_credential_defresult
char *
guestfs_get_libvirt_requested_credential_defresult (guestfs_h *g,
int index);
Get the default result (provided by libvirt) for the "index"'th requested credential. If libvirt did not
provide a default result, this returns the empty string "".
See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.52)
guestfs_get_libvirt_requested_credential_prompt
char *
guestfs_get_libvirt_requested_credential_prompt (guestfs_h *g,
int index);
Get the prompt (provided by libvirt) for the "index"'th requested credential. If libvirt did not provide
a prompt, this returns the empty string "".
See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.52)
guestfs_get_libvirt_requested_credentials
char **
guestfs_get_libvirt_requested_credentials (guestfs_h *g);
This should only be called during the event callback for events of type "GUESTFS_EVENT_LIBVIRT_AUTH".
Return the list of credentials requested by libvirt. Possible values are a subset of the strings
provided when you called "guestfs_set_libvirt_supported_credentials".
See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.19.52)
guestfs_get_memsize
int
guestfs_get_memsize (guestfs_h *g);
This gets the memory size in megabytes allocated to the hypervisor.
If "guestfs_set_memsize" was not called on this handle, and if "LIBGUESTFS_MEMSIZE" was not set, then
this returns the compiled-in default value for memsize.
For more information on the architecture of libguestfs, see guestfs(3).
On error this function returns -1.
(Added in 1.0.55)
guestfs_get_network
int
guestfs_get_network (guestfs_h *g);
This returns the enable network flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.5.4)
guestfs_get_path
const char *
guestfs_get_path (guestfs_h *g);
Return the current search path.
This is always non-NULL. If it wasn't set already, then this will return the default path.
This function returns a string, or NULL on error. The string is owned by the guest handle and must not
be freed.
(Added in 0.3)
guestfs_get_pgroup
int
guestfs_get_pgroup (guestfs_h *g);
This returns the process group flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.11.18)
guestfs_get_pid
int
guestfs_get_pid (guestfs_h *g);
Return the process ID of the hypervisor. If there is no hypervisor running, then this will return an
error.
This is an internal call used for debugging and testing.
On error this function returns -1.
(Added in 1.0.56)
guestfs_get_program
const char *
guestfs_get_program (guestfs_h *g);
Get the program name. See "guestfs_set_program".
This function returns a string, or NULL on error. The string is owned by the guest handle and must not
be freed.
(Added in 1.21.29)
guestfs_get_qemu
const char *
guestfs_get_qemu (guestfs_h *g);
This function is deprecated. In new code, use the "guestfs_get_hv" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
Return the current hypervisor binary (usually qemu).
This is always non-NULL. If it wasn't set already, then this will return the default qemu binary name.
This function returns a string, or NULL on error. The string is owned by the guest handle and must not
be freed.
(Added in 1.0.6)
guestfs_get_recovery_proc
int
guestfs_get_recovery_proc (guestfs_h *g);
Return the recovery process enabled flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.0.77)
guestfs_get_selinux
int
guestfs_get_selinux (guestfs_h *g);
This returns the current setting of the selinux flag which is passed to the appliance at boot time. See
"guestfs_set_selinux".
For more information on the architecture of libguestfs, see guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.0.67)
guestfs_get_smp
int
guestfs_get_smp (guestfs_h *g);
This returns the number of virtual CPUs assigned to the appliance.
On error this function returns -1.
(Added in 1.13.15)
guestfs_get_state
int
guestfs_get_state (guestfs_h *g);
This returns the current state as an opaque integer. This is only useful for printing debug and internal
error messages.
For more information on states, see guestfs(3).
On error this function returns -1.
(Added in 1.0.2)
guestfs_get_tmpdir
char *
guestfs_get_tmpdir (guestfs_h *g);
Get the directory used by the handle to store temporary files.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.58)
guestfs_get_trace
int
guestfs_get_trace (guestfs_h *g);
Return the command trace flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.0.69)
guestfs_get_umask
int
guestfs_get_umask (guestfs_h *g);
Return the current umask. By default the umask is 022 unless it has been set by calling "guestfs_umask".
On error this function returns -1.
(Added in 1.3.4)
guestfs_get_verbose
int
guestfs_get_verbose (guestfs_h *g);
This returns the verbose messages flag.
This function returns a C truth value on success or -1 on error.
(Added in 0.3)
guestfs_getcon
char *
guestfs_getcon (guestfs_h *g);
This gets the SELinux security context of the daemon.
See the documentation about SELINUX in guestfs(3), and "guestfs_setcon"
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.67)
guestfs_getxattr
char *
guestfs_getxattr (guestfs_h *g,
const char *path,
const char *name,
size_t *size_r);
Get a single extended attribute from file "path" named "name". This call follows symlinks. If you want
to lookup an extended attribute for the symlink itself, use "guestfs_lgetxattr".
Normally it is better to get all extended attributes from a file in one go by calling
"guestfs_getxattrs". However some Linux filesystem implementations are buggy and do not provide a way to
list out attributes. For these filesystems (notably ntfs-3g) you have to know the names of the extended
attributes you want in advance and call this function.
Extended attribute values are blobs of binary data. If there is no extended attribute named "name", this
returns an error.
See also: "guestfs_getxattrs", "guestfs_lgetxattr", attr(5).
This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r.
The caller must free the returned buffer after use.
(Added in 1.7.24)
guestfs_getxattrs
struct guestfs_xattr_list *
guestfs_getxattrs (guestfs_h *g,
const char *path);
This call lists the extended attributes of the file or directory "path".
At the system call level, this is a combination of the listxattr(2) and getxattr(2) calls.
See also: "guestfs_lgetxattrs", attr(5).
This function returns a "struct guestfs_xattr_list *", or NULL if there was an error. The caller must
call "guestfs_free_xattr_list" after use.
(Added in 1.0.59)
guestfs_glob_expand
char **
guestfs_glob_expand (guestfs_h *g,
const char *pattern);
This command searches for all the pathnames matching "pattern" according to the wildcard expansion rules
used by the shell.
If no paths match, then this returns an empty list (note: not an error).
It is just a wrapper around the C glob(3) function with flags "GLOB_MARK|GLOB_BRACE". See that manual
page for more details.
Notice that there is no equivalent command for expanding a device name (eg. "/dev/sd*"). Use
"guestfs_list_devices", "guestfs_list_partitions" etc functions instead.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.0.50)
guestfs_grep
char **
guestfs_grep (guestfs_h *g,
const char *regex,
const char *path);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_grep_opts" with no optional arguments.
(Added in 1.0.66)
guestfs_grep_opts
char **
guestfs_grep_opts (guestfs_h *g,
const char *regex,
const char *path,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_GREP_OPTS_EXTENDED, int extended,
GUESTFS_GREP_OPTS_FIXED, int fixed,
GUESTFS_GREP_OPTS_INSENSITIVE, int insensitive,
GUESTFS_GREP_OPTS_COMPRESSED, int compressed,
This calls the external "grep" program and returns the matching lines.
The optional flags are:
"extended"
Use extended regular expressions. This is the same as using the -E flag.
"fixed"
Match fixed (don't use regular expressions). This is the same as using the -F flag.
"insensitive"
Match case-insensitive. This is the same as using the -i flag.
"compressed"
Use "zgrep" instead of "grep". This allows the input to be compress- or gzip-compressed.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.19.28)
guestfs_grep_opts_va
char **
guestfs_grep_opts_va (guestfs_h *g,
const char *regex,
const char *path,
va_list args);
This is the "va_list variant" of "guestfs_grep_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_grep_opts_argv
char **
guestfs_grep_opts_argv (guestfs_h *g,
const char *regex,
const char *path,
const struct guestfs_grep_opts_argv *optargs);
This is the "argv variant" of "guestfs_grep_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_grepi
char **
guestfs_grepi (guestfs_h *g,
const char *regex,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "grep -i" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_grub_install
int
guestfs_grub_install (guestfs_h *g,
const char *root,
const char *device);
This command installs GRUB 1 (the Grand Unified Bootloader) on "device", with the root directory being
"root".
Notes:
• There is currently no way in the API to install grub2, which is used by most modern Linux guests. It
is possible to run the grub2 command from the guest, although see the caveats in "RUNNING COMMANDS"
in guestfs(3).
• This uses "grub-install" from the host. Unfortunately grub is not always compatible with itself, so
this only works in rather narrow circumstances. Careful testing with each guest version is
advisable.
• If grub-install reports the error "No suitable drive was found in the generated device map." it may
be that you need to create a "/boot/grub/device.map" file first that contains the mapping between
grub device names and Linux device names. It is usually sufficient to create a file containing:
(hd0) /dev/vda
replacing "/dev/vda" with the name of the installation device.
This function returns 0 on success or -1 on error.
(Added in 1.0.17)
guestfs_head
char **
guestfs_head (guestfs_h *g,
const char *path);
This command returns up to the first 10 lines of a file as a list of strings.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.54)
guestfs_head_n
char **
guestfs_head_n (guestfs_h *g,
int nrlines,
const char *path);
If the parameter "nrlines" is a positive number, this returns the first "nrlines" lines of the file
"path".
If the parameter "nrlines" is a negative number, this returns lines from the file "path", excluding the
last "nrlines" lines.
If the parameter "nrlines" is zero, this returns an empty list.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.54)
guestfs_hexdump
char *
guestfs_hexdump (guestfs_h *g,
const char *path);
This runs "hexdump -C" on the given "path". The result is the human-readable, canonical hex dump of the
file.
This function returns a string, or NULL on error. The caller must free the returned string after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.22)
guestfs_hivex_close
int
guestfs_hivex_close (guestfs_h *g);
Close the current hivex handle.
This is a wrapper around the hivex(3) call of the same name.
This function returns 0 on success or -1 on error.
(Added in 1.19.35)
guestfs_hivex_commit
int
guestfs_hivex_commit (guestfs_h *g,
const char *filename);
Commit (write) changes to the hive.
If the optional "filename" parameter is null, then the changes are written back to the same hive that was
opened. If this is not null then they are written to the alternate filename given and the original hive
is left untouched.
This is a wrapper around the hivex(3) call of the same name.
This function returns 0 on success or -1 on error.
(Added in 1.19.35)
guestfs_hivex_node_add_child
int64_t
guestfs_hivex_node_add_child (guestfs_h *g,
int64_t parent,
const char *name);
Add a child node to "parent" named "name".
This is a wrapper around the hivex(3) call of the same name.
On error this function returns -1.
(Added in 1.19.35)
guestfs_hivex_node_children
struct guestfs_hivex_node_list *
guestfs_hivex_node_children (guestfs_h *g,
int64_t nodeh);
Return the list of nodes which are subkeys of "nodeh".
This is a wrapper around the hivex(3) call of the same name.
This function returns a "struct guestfs_hivex_node_list *", or NULL if there was an error. The caller
must call "guestfs_free_hivex_node_list" after use.
(Added in 1.19.35)
guestfs_hivex_node_delete_child
int
guestfs_hivex_node_delete_child (guestfs_h *g,
int64_t nodeh);
Delete "nodeh", recursively if necessary.
This is a wrapper around the hivex(3) call of the same name.
This function returns 0 on success or -1 on error.
(Added in 1.19.35)
guestfs_hivex_node_get_child
int64_t
guestfs_hivex_node_get_child (guestfs_h *g,
int64_t nodeh,
const char *name);
Return the child of "nodeh" with the name "name", if it exists. This can return 0 meaning the name was
not found.
This is a wrapper around the hivex(3) call of the same name.
On error this function returns -1.
(Added in 1.19.35)
guestfs_hivex_node_get_value
int64_t
guestfs_hivex_node_get_value (guestfs_h *g,
int64_t nodeh,
const char *key);
Return the value attached to "nodeh" which has the name "key", if it exists. This can return 0 meaning
the key was not found.
This is a wrapper around the hivex(3) call of the same name.
On error this function returns -1.
(Added in 1.19.35)
guestfs_hivex_node_name
char *
guestfs_hivex_node_name (guestfs_h *g,
int64_t nodeh);
Return the name of "nodeh".
This is a wrapper around the hivex(3) call of the same name.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.35)
guestfs_hivex_node_parent
int64_t
guestfs_hivex_node_parent (guestfs_h *g,
int64_t nodeh);
Return the parent node of "nodeh".
This is a wrapper around the hivex(3) call of the same name.
On error this function returns -1.
(Added in 1.19.35)
guestfs_hivex_node_set_value
int
guestfs_hivex_node_set_value (guestfs_h *g,
int64_t nodeh,
const char *key,
int64_t t,
const char *val,
size_t val_size);
Set or replace a single value under the node "nodeh". The "key" is the name, "t" is the type, and "val"
is the data.
This is a wrapper around the hivex(3) call of the same name.
This function returns 0 on success or -1 on error.
(Added in 1.19.35)
guestfs_hivex_node_values
struct guestfs_hivex_value_list *
guestfs_hivex_node_values (guestfs_h *g,
int64_t nodeh);
Return the array of (key, datatype, data) tuples attached to "nodeh".
This is a wrapper around the hivex(3) call of the same name.
This function returns a "struct guestfs_hivex_value_list *", or NULL if there was an error. The caller
must call "guestfs_free_hivex_value_list" after use.
(Added in 1.19.35)
guestfs_hivex_open
int
guestfs_hivex_open (guestfs_h *g,
const char *filename,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_HIVEX_OPEN_VERBOSE, int verbose,
GUESTFS_HIVEX_OPEN_DEBUG, int debug,
GUESTFS_HIVEX_OPEN_WRITE, int write,
Open the Windows Registry hive file named "filename". If there was any previous hivex handle associated
with this guestfs session, then it is closed.
This is a wrapper around the hivex(3) call of the same name.
This function returns 0 on success or -1 on error.
(Added in 1.19.35)
guestfs_hivex_open_va
int
guestfs_hivex_open_va (guestfs_h *g,
const char *filename,
va_list args);
This is the "va_list variant" of "guestfs_hivex_open".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_hivex_open_argv
int
guestfs_hivex_open_argv (guestfs_h *g,
const char *filename,
const struct guestfs_hivex_open_argv *optargs);
This is the "argv variant" of "guestfs_hivex_open".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_hivex_root
int64_t
guestfs_hivex_root (guestfs_h *g);
Return the root node of the hive.
This is a wrapper around the hivex(3) call of the same name.
On error this function returns -1.
(Added in 1.19.35)
guestfs_hivex_value_key
char *
guestfs_hivex_value_key (guestfs_h *g,
int64_t valueh);
Return the key (name) field of a (key, datatype, data) tuple.
This is a wrapper around the hivex(3) call of the same name.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.35)
guestfs_hivex_value_type
int64_t
guestfs_hivex_value_type (guestfs_h *g,
int64_t valueh);
Return the data type field from a (key, datatype, data) tuple.
This is a wrapper around the hivex(3) call of the same name.
On error this function returns -1.
(Added in 1.19.35)
guestfs_hivex_value_utf8
char *
guestfs_hivex_value_utf8 (guestfs_h *g,
int64_t valueh);
This calls "guestfs_hivex_value_value" (which returns the data field from a hivex value tuple). It then
assumes that the field is a UTF-16LE string and converts the result to UTF-8 (or if this is not possible,
it returns an error).
This is useful for reading strings out of the Windows registry. However it is not foolproof because the
registry is not strongly-typed and fields can contain arbitrary or unexpected data.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.35)
guestfs_hivex_value_value
char *
guestfs_hivex_value_value (guestfs_h *g,
int64_t valueh,
size_t *size_r);
Return the data field of a (key, datatype, data) tuple.
This is a wrapper around the hivex(3) call of the same name.
See also: "guestfs_hivex_value_utf8".
This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r.
The caller must free the returned buffer after use.
(Added in 1.19.35)
guestfs_initrd_cat
char *
guestfs_initrd_cat (guestfs_h *g,
const char *initrdpath,
const char *filename,
size_t *size_r);
This command unpacks the file "filename" from the initrd file called "initrdpath". The filename must be
given without the initial "/" character.
For example, in guestfish you could use the following command to examine the boot script (usually called
"/init") contained in a Linux initrd or initramfs image:
initrd-cat /boot/initrd-<version>.img init
See also "guestfs_initrd_list".
This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r.
The caller must free the returned buffer after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.84)
guestfs_initrd_list
char **
guestfs_initrd_list (guestfs_h *g,
const char *path);
This command lists out files contained in an initrd.
The files are listed without any initial "/" character. The files are listed in the order they appear
(not necessarily alphabetical). Directory names are listed as separate items.
Old Linux kernels (2.4 and earlier) used a compressed ext2 filesystem as initrd. We only support the
newer initramfs format (compressed cpio files).
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.0.54)
guestfs_inotify_add_watch
int64_t
guestfs_inotify_add_watch (guestfs_h *g,
const char *path,
int mask);
Watch "path" for the events listed in "mask".
Note that if "path" is a directory then events within that directory are watched, but this does not
happen recursively (in subdirectories).
Note for non-C or non-Linux callers: the inotify events are defined by the Linux kernel ABI and are
listed in "/usr/include/sys/inotify.h".
On error this function returns -1.
(Added in 1.0.66)
guestfs_inotify_close
int
guestfs_inotify_close (guestfs_h *g);
This closes the inotify handle which was previously opened by inotify_init. It removes all watches,
throws away any pending events, and deallocates all resources.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_inotify_files
char **
guestfs_inotify_files (guestfs_h *g);
This function is a helpful wrapper around "guestfs_inotify_read" which just returns a list of pathnames
of objects that were touched. The returned pathnames are sorted and deduplicated.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.0.66)
guestfs_inotify_init
int
guestfs_inotify_init (guestfs_h *g,
int maxevents);
This command creates a new inotify handle. The inotify subsystem can be used to notify events which
happen to objects in the guest filesystem.
"maxevents" is the maximum number of events which will be queued up between calls to
"guestfs_inotify_read" or "guestfs_inotify_files". If this is passed as 0, then the kernel (or
previously set) default is used. For Linux 2.6.29 the default was 16384 events. Beyond this limit, the
kernel throws away events, but records the fact that it threw them away by setting a flag "IN_Q_OVERFLOW"
in the returned structure list (see "guestfs_inotify_read").
Before any events are generated, you have to add some watches to the internal watch list. See:
"guestfs_inotify_add_watch" and "guestfs_inotify_rm_watch".
Queued up events should be read periodically by calling "guestfs_inotify_read" (or
"guestfs_inotify_files" which is just a helpful wrapper around "guestfs_inotify_read"). If you don't
read the events out often enough then you risk the internal queue overflowing.
The handle should be closed after use by calling "guestfs_inotify_close". This also removes any watches
automatically.
See also inotify(7) for an overview of the inotify interface as exposed by the Linux kernel, which is
roughly what we expose via libguestfs. Note that there is one global inotify handle per libguestfs
instance.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_inotify_read
struct guestfs_inotify_event_list *
guestfs_inotify_read (guestfs_h *g);
Return the complete queue of events that have happened since the previous read call.
If no events have happened, this returns an empty list.
Note: In order to make sure that all events have been read, you must call this function repeatedly until
it returns an empty list. The reason is that the call will read events up to the maximum appliance-to-
host message size and leave remaining events in the queue.
This function returns a "struct guestfs_inotify_event_list *", or NULL if there was an error. The caller
must call "guestfs_free_inotify_event_list" after use.
(Added in 1.0.66)
guestfs_inotify_rm_watch
int
guestfs_inotify_rm_watch (guestfs_h *g,
int wd);
Remove a previously defined inotify watch. See "guestfs_inotify_add_watch".
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_inspect_get_arch
char *
guestfs_inspect_get_arch (guestfs_h *g,
const char *root);
This returns the architecture of the inspected operating system. The possible return values are listed
under "guestfs_file_architecture".
If the architecture could not be determined, then the string "unknown" is returned.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.3)
guestfs_inspect_get_distro
char *
guestfs_inspect_get_distro (guestfs_h *g,
const char *root);
This returns the distro (distribution) of the inspected operating system.
Currently defined distros are:
"archlinux"
Arch Linux.
"buildroot"
Buildroot-derived distro, but not one we specifically recognize.
"centos"
CentOS.
"cirros"
Cirros.
"debian"
Debian.
"fedora"
Fedora.
"freedos"
FreeDOS.
"gentoo"
Gentoo.
"linuxmint"
Linux Mint.
"mageia"
Mageia.
"mandriva"
Mandriva.
"meego"
MeeGo.
"openbsd"
OpenBSD.
"opensuse"
OpenSUSE.
"pardus"
Pardus.
"redhat-based"
Some Red Hat-derived distro.
"rhel"
Red Hat Enterprise Linux.
"scientificlinux"
Scientific Linux.
"slackware"
Slackware.
"sles"
SuSE Linux Enterprise Server or Desktop.
"suse-based"
Some openSuSE-derived distro.
"ttylinux"
ttylinux.
"ubuntu"
Ubuntu.
"unknown"
The distro could not be determined.
"windows"
Windows does not have distributions. This string is returned if the OS type is Windows.
Future versions of libguestfs may return other strings here. The caller should be prepared to handle any
string.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.3)
guestfs_inspect_get_drive_mappings
char **
guestfs_inspect_get_drive_mappings (guestfs_h *g,
const char *root);
This call is useful for Windows which uses a primitive system of assigning drive letters (like "C:") to
partitions. This inspection API examines the Windows Registry to find out how disks/partitions are
mapped to drive letters, and returns a hash table as in the example below:
C => /dev/vda2
E => /dev/vdb1
F => /dev/vdc1
Note that keys are drive letters. For Windows, the key is case insensitive and just contains the drive
letter, without the customary colon separator character.
In future we may support other operating systems that also used drive letters, but the keys for those
might not be case insensitive and might be longer than 1 character. For example in OS-9, hard drives
were named "h0", "h1" etc.
For Windows guests, currently only hard drive mappings are returned. Removable disks (eg. DVD-ROMs) are
ignored.
For guests that do not use drive mappings, or if the drive mappings could not be determined, this returns
an empty hash table.
Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_mountpoints",
"guestfs_inspect_get_filesystems".
This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of
strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing
NULL entry. The caller must free the strings and the array after use.
(Added in 1.9.17)
guestfs_inspect_get_filesystems
char **
guestfs_inspect_get_filesystems (guestfs_h *g,
const char *root);
This returns a list of all the filesystems that we think are associated with this operating system. This
includes the root filesystem, other ordinary filesystems, and non-mounted devices like swap partitions.
In the case of a multi-boot virtual machine, it is possible for a filesystem to be shared between
operating systems.
Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_mountpoints".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.5.3)
guestfs_inspect_get_format
char *
guestfs_inspect_get_format (guestfs_h *g,
const char *root);
This returns the format of the inspected operating system. You can use it to detect install images, live
CDs and similar.
Currently defined formats are:
"installed"
This is an installed operating system.
"installer"
The disk image being inspected is not an installed operating system, but a bootable install disk,
live CD, or similar.
"unknown"
The format of this disk image is not known.
Future versions of libguestfs may return other strings here. The caller should be prepared to handle any
string.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.9.4)
guestfs_inspect_get_hostname
char *
guestfs_inspect_get_hostname (guestfs_h *g,
const char *root);
This function returns the hostname of the operating system as found by inspection of the guest's
configuration files.
If the hostname could not be determined, then the string "unknown" is returned.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.7.9)
guestfs_inspect_get_icon
char *
guestfs_inspect_get_icon (guestfs_h *g,
const char *root,
size_t *size_r,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_INSPECT_GET_ICON_FAVICON, int favicon,
GUESTFS_INSPECT_GET_ICON_HIGHQUALITY, int highquality,
This function returns an icon corresponding to the inspected operating system. The icon is returned as a
buffer containing a PNG image (re-encoded to PNG if necessary).
If it was not possible to get an icon this function returns a zero-length (non-NULL) buffer. Callers
must check for this case.
Libguestfs will start by looking for a file called "/etc/favicon.png" or "C:\etc\favicon.png" and if it
has the correct format, the contents of this file will be returned. You can disable favicons by passing
the optional "favicon" boolean as false (default is true).
If finding the favicon fails, then we look in other places in the guest for a suitable icon.
If the optional "highquality" boolean is true then only high quality icons are returned, which means only
icons of high resolution with an alpha channel. The default (false) is to return any icon we can, even
if it is of substandard quality.
Notes:
• Unlike most other inspection API calls, the guest's disks must be mounted up before you call this,
since it needs to read information from the guest filesystem during the call.
• Security: The icon data comes from the untrusted guest, and should be treated with caution. PNG
files have been known to contain exploits. Ensure that libpng (or other relevant libraries) are
fully up to date before trying to process or display the icon.
• The PNG image returned can be any size. It might not be square. Libguestfs tries to return the
largest, highest quality icon available. The application must scale the icon to the required size.
• Extracting icons from Windows guests requires the external "wrestool" program from the "icoutils"
package, and several programs ("bmptopnm", "pnmtopng", "pamcut") from the "netpbm" package. These
must be installed separately.
• Operating system icons are usually trademarks. Seek legal advice before using trademarks in
applications.
This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r.
The caller must free the returned buffer after use.
(Added in 1.11.12)
guestfs_inspect_get_icon_va
char *
guestfs_inspect_get_icon_va (guestfs_h *g,
const char *root,
size_t *size_r,
va_list args);
This is the "va_list variant" of "guestfs_inspect_get_icon".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_inspect_get_icon_argv
char *
guestfs_inspect_get_icon_argv (guestfs_h *g,
const char *root,
size_t *size_r,
const struct guestfs_inspect_get_icon_argv *optargs);
This is the "argv variant" of "guestfs_inspect_get_icon".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_inspect_get_major_version
int
guestfs_inspect_get_major_version (guestfs_h *g,
const char *root);
This returns the major version number of the inspected operating system.
Windows uses a consistent versioning scheme which is not reflected in the popular public names used by
the operating system. Notably the operating system known as "Windows 7" is really version 6.1 (ie. major
= 6, minor = 1). You can find out the real versions corresponding to releases of Windows by consulting
Wikipedia or MSDN.
If the version could not be determined, then 0 is returned.
Please read "INSPECTION" in guestfs(3) for more details.
On error this function returns -1.
(Added in 1.5.3)
guestfs_inspect_get_minor_version
int
guestfs_inspect_get_minor_version (guestfs_h *g,
const char *root);
This returns the minor version number of the inspected operating system.
If the version could not be determined, then 0 is returned.
Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_major_version".
On error this function returns -1.
(Added in 1.5.3)
guestfs_inspect_get_mountpoints
char **
guestfs_inspect_get_mountpoints (guestfs_h *g,
const char *root);
This returns a hash of where we think the filesystems associated with this operating system should be
mounted. Callers should note that this is at best an educated guess made by reading configuration files
such as "/etc/fstab". In particular note that this may return filesystems which are non-existent or not
mountable and callers should be prepared to handle or ignore failures if they try to mount them.
Each element in the returned hashtable has a key which is the path of the mountpoint (eg. "/boot") and a
value which is the filesystem that would be mounted there (eg. "/dev/sda1").
Non-mounted devices such as swap devices are not returned in this list.
For operating systems like Windows which still use drive letters, this call will only return an entry for
the first drive "mounted on" "/". For information about the mapping of drive letters to partitions, see
"guestfs_inspect_get_drive_mappings".
Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_filesystems".
This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of
strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing
NULL entry. The caller must free the strings and the array after use.
(Added in 1.5.3)
guestfs_inspect_get_package_format
char *
guestfs_inspect_get_package_format (guestfs_h *g,
const char *root);
This function and "guestfs_inspect_get_package_management" return the package format and package
management tool used by the inspected operating system. For example for Fedora these functions would
return "rpm" (package format) and "yum" (package management).
This returns the string "unknown" if we could not determine the package format or if the operating system
does not have a real packaging system (eg. Windows).
Possible strings include: "rpm", "deb", "ebuild", "pisi", "pacman", "pkgsrc". Future versions of
libguestfs may return other strings.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.7.5)
guestfs_inspect_get_package_management
char *
guestfs_inspect_get_package_management (guestfs_h *g,
const char *root);
"guestfs_inspect_get_package_format" and this function return the package format and package management
tool used by the inspected operating system. For example for Fedora these functions would return "rpm"
(package format) and "yum" (package management).
This returns the string "unknown" if we could not determine the package management tool or if the
operating system does not have a real packaging system (eg. Windows).
Possible strings include: "yum", "up2date", "apt" (for all Debian derivatives), "portage", "pisi",
"pacman", "urpmi", "zypper". Future versions of libguestfs may return other strings.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.7.5)
guestfs_inspect_get_product_name
char *
guestfs_inspect_get_product_name (guestfs_h *g,
const char *root);
This returns the product name of the inspected operating system. The product name is generally some
freeform string which can be displayed to the user, but should not be parsed by programs.
If the product name could not be determined, then the string "unknown" is returned.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.3)
guestfs_inspect_get_product_variant
char *
guestfs_inspect_get_product_variant (guestfs_h *g,
const char *root);
This returns the product variant of the inspected operating system.
For Windows guests, this returns the contents of the Registry key "HKLM\Software\Microsoft\Windows
NT\CurrentVersion" "InstallationType" which is usually a string such as "Client" or "Server" (other
values are possible). This can be used to distinguish consumer and enterprise versions of Windows that
have the same version number (for example, Windows 7 and Windows 2008 Server are both version 6.1, but
the former is "Client" and the latter is "Server").
For enterprise Linux guests, in future we intend this to return the product variant such as "Desktop",
"Server" and so on. But this is not implemented at present.
If the product variant could not be determined, then the string "unknown" is returned.
Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_product_name",
"guestfs_inspect_get_major_version".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.9.13)
guestfs_inspect_get_roots
char **
guestfs_inspect_get_roots (guestfs_h *g);
This function is a convenient way to get the list of root devices, as returned from a previous call to
"guestfs_inspect_os", but without redoing the whole inspection process.
This returns an empty list if either no root devices were found or the caller has not called
"guestfs_inspect_os".
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.7.3)
guestfs_inspect_get_type
char *
guestfs_inspect_get_type (guestfs_h *g,
const char *root);
This returns the type of the inspected operating system. Currently defined types are:
"linux"
Any Linux-based operating system.
"windows"
Any Microsoft Windows operating system.
"freebsd"
FreeBSD.
"netbsd"
NetBSD.
"openbsd"
OpenBSD.
"hurd"
GNU/Hurd.
"dos"
MS-DOS, FreeDOS and others.
"unknown"
The operating system type could not be determined.
Future versions of libguestfs may return other strings here. The caller should be prepared to handle any
string.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.3)
guestfs_inspect_get_windows_current_control_set
char *
guestfs_inspect_get_windows_current_control_set (guestfs_h *g,
const char *root);
This returns the Windows CurrentControlSet of the inspected guest. The CurrentControlSet is a registry
key name such as "ControlSet001".
This call assumes that the guest is Windows and that the Registry could be examined by inspection. If
this is not the case then an error is returned.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.9.17)
guestfs_inspect_get_windows_systemroot
char *
guestfs_inspect_get_windows_systemroot (guestfs_h *g,
const char *root);
This returns the Windows systemroot of the inspected guest. The systemroot is a directory path such as
"/WINDOWS".
This call assumes that the guest is Windows and that the systemroot could be determined by inspection.
If this is not the case then an error is returned.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.25)
guestfs_inspect_is_live
int
guestfs_inspect_is_live (guestfs_h *g,
const char *root);
If "guestfs_inspect_get_format" returns "installer" (this is an install disk), then this returns true if
a live image was detected on the disk.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a C truth value on success or -1 on error.
(Added in 1.9.4)
guestfs_inspect_is_multipart
int
guestfs_inspect_is_multipart (guestfs_h *g,
const char *root);
If "guestfs_inspect_get_format" returns "installer" (this is an install disk), then this returns true if
the disk is part of a set.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a C truth value on success or -1 on error.
(Added in 1.9.4)
guestfs_inspect_is_netinst
int
guestfs_inspect_is_netinst (guestfs_h *g,
const char *root);
If "guestfs_inspect_get_format" returns "installer" (this is an install disk), then this returns true if
the disk is a network installer, ie. not a self-contained install CD but one which is likely to require
network access to complete the install.
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a C truth value on success or -1 on error.
(Added in 1.9.4)
guestfs_inspect_list_applications
struct guestfs_application_list *
guestfs_inspect_list_applications (guestfs_h *g,
const char *root);
This function is deprecated. In new code, use the "guestfs_inspect_list_applications2" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
Return the list of applications installed in the operating system.
Note: This call works differently from other parts of the inspection API. You have to call
"guestfs_inspect_os", then "guestfs_inspect_get_mountpoints", then mount up the disks, before calling
this. Listing applications is a significantly more difficult operation which requires access to the full
filesystem. Also note that unlike the other "guestfs_inspect_get_*" calls which are just returning data
cached in the libguestfs handle, this call actually reads parts of the mounted filesystems during the
call.
This returns an empty list if the inspection code was not able to determine the list of applications.
The application structure contains the following fields:
"app_name"
The name of the application. For Red Hat-derived and Debian-derived Linux guests, this is the
package name.
"app_display_name"
The display name of the application, sometimes localized to the install language of the guest
operating system.
If unavailable this is returned as an empty string "". Callers needing to display something can use
"app_name" instead.
"app_epoch"
For package managers which use epochs, this contains the epoch of the package (an integer). If
unavailable, this is returned as 0.
"app_version"
The version string of the application or package. If unavailable this is returned as an empty string
"".
"app_release"
The release string of the application or package, for package managers that use this. If unavailable
this is returned as an empty string "".
"app_install_path"
The installation path of the application (on operating systems such as Windows which use installation
paths). This path is in the format used by the guest operating system, it is not a libguestfs path.
If unavailable this is returned as an empty string "".
"app_trans_path"
The install path translated into a libguestfs path. If unavailable this is returned as an empty
string "".
"app_publisher"
The name of the publisher of the application, for package managers that use this. If unavailable
this is returned as an empty string "".
"app_url"
The URL (eg. upstream URL) of the application. If unavailable this is returned as an empty string
"".
"app_source_package"
For packaging systems which support this, the name of the source package. If unavailable this is
returned as an empty string "".
"app_summary"
A short (usually one line) description of the application or package. If unavailable this is
returned as an empty string "".
"app_description"
A longer description of the application or package. If unavailable this is returned as an empty
string "".
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a "struct guestfs_application_list *", or NULL if there was an error. The caller
must call "guestfs_free_application_list" after use.
(Added in 1.7.8)
guestfs_inspect_list_applications2
struct guestfs_application2_list *
guestfs_inspect_list_applications2 (guestfs_h *g,
const char *root);
Return the list of applications installed in the operating system.
Note: This call works differently from other parts of the inspection API. You have to call
"guestfs_inspect_os", then "guestfs_inspect_get_mountpoints", then mount up the disks, before calling
this. Listing applications is a significantly more difficult operation which requires access to the full
filesystem. Also note that unlike the other "guestfs_inspect_get_*" calls which are just returning data
cached in the libguestfs handle, this call actually reads parts of the mounted filesystems during the
call.
This returns an empty list if the inspection code was not able to determine the list of applications.
The application structure contains the following fields:
"app2_name"
The name of the application. For Red Hat-derived and Debian-derived Linux guests, this is the
package name.
"app2_display_name"
The display name of the application, sometimes localized to the install language of the guest
operating system.
If unavailable this is returned as an empty string "". Callers needing to display something can use
"app2_name" instead.
"app2_epoch"
For package managers which use epochs, this contains the epoch of the package (an integer). If
unavailable, this is returned as 0.
"app2_version"
The version string of the application or package. If unavailable this is returned as an empty string
"".
"app2_release"
The release string of the application or package, for package managers that use this. If unavailable
this is returned as an empty string "".
"app2_arch"
The architecture string of the application or package, for package managers that use this. If
unavailable this is returned as an empty string "".
"app2_install_path"
The installation path of the application (on operating systems such as Windows which use installation
paths). This path is in the format used by the guest operating system, it is not a libguestfs path.
If unavailable this is returned as an empty string "".
"app2_trans_path"
The install path translated into a libguestfs path. If unavailable this is returned as an empty
string "".
"app2_publisher"
The name of the publisher of the application, for package managers that use this. If unavailable
this is returned as an empty string "".
"app2_url"
The URL (eg. upstream URL) of the application. If unavailable this is returned as an empty string
"".
"app2_source_package"
For packaging systems which support this, the name of the source package. If unavailable this is
returned as an empty string "".
"app2_summary"
A short (usually one line) description of the application or package. If unavailable this is
returned as an empty string "".
"app2_description"
A longer description of the application or package. If unavailable this is returned as an empty
string "".
Please read "INSPECTION" in guestfs(3) for more details.
This function returns a "struct guestfs_application2_list *", or NULL if there was an error. The caller
must call "guestfs_free_application2_list" after use.
(Added in 1.19.56)
guestfs_inspect_os
char **
guestfs_inspect_os (guestfs_h *g);
This function uses other libguestfs functions and certain heuristics to inspect the disk(s) (usually
disks belonging to a virtual machine), looking for operating systems.
The list returned is empty if no operating systems were found.
If one operating system was found, then this returns a list with a single element, which is the name of
the root filesystem of this operating system. It is also possible for this function to return a list
containing more than one element, indicating a dual-boot or multi-boot virtual machine, with each element
being the root filesystem of one of the operating systems.
You can pass the root string(s) returned to other "guestfs_inspect_get_*" functions in order to query
further information about each operating system, such as the name and version.
This function uses other libguestfs features such as "guestfs_mount_ro" and "guestfs_umount_all" in order
to mount and unmount filesystems and look at the contents. This should be called with no disks currently
mounted. The function may also use Augeas, so any existing Augeas handle will be closed.
This function cannot decrypt encrypted disks. The caller must do that first (supplying the necessary
keys) if the disk is encrypted.
Please read "INSPECTION" in guestfs(3) for more details.
See also "guestfs_list_filesystems".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.5.3)
guestfs_is_blockdev
int
guestfs_is_blockdev (guestfs_h *g,
const char *path);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_is_blockdev_opts" with no optional arguments.
(Added in 1.5.10)
guestfs_is_blockdev_opts
int
guestfs_is_blockdev_opts (guestfs_h *g,
const char *path,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_IS_BLOCKDEV_OPTS_FOLLOWSYMLINKS, int followsymlinks,
This returns "true" if and only if there is a block device with the given "path" name.
If the optional flag "followsymlinks" is true, then a symlink (or chain of symlinks) that ends with a
block device also causes the function to return true.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.23.4)
guestfs_is_blockdev_opts_va
int
guestfs_is_blockdev_opts_va (guestfs_h *g,
const char *path,
va_list args);
This is the "va_list variant" of "guestfs_is_blockdev_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_blockdev_opts_argv
int
guestfs_is_blockdev_opts_argv (guestfs_h *g,
const char *path,
const struct guestfs_is_blockdev_opts_argv *optargs);
This is the "argv variant" of "guestfs_is_blockdev_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_busy
int
guestfs_is_busy (guestfs_h *g);
This always returns false. This function is deprecated with no replacement. Do not use this function.
For more information on states, see guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.0.2)
guestfs_is_chardev
int
guestfs_is_chardev (guestfs_h *g,
const char *path);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_is_chardev_opts" with no optional arguments.
(Added in 1.5.10)
guestfs_is_chardev_opts
int
guestfs_is_chardev_opts (guestfs_h *g,
const char *path,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_IS_CHARDEV_OPTS_FOLLOWSYMLINKS, int followsymlinks,
This returns "true" if and only if there is a character device with the given "path" name.
If the optional flag "followsymlinks" is true, then a symlink (or chain of symlinks) that ends with a
chardev also causes the function to return true.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.23.4)
guestfs_is_chardev_opts_va
int
guestfs_is_chardev_opts_va (guestfs_h *g,
const char *path,
va_list args);
This is the "va_list variant" of "guestfs_is_chardev_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_chardev_opts_argv
int
guestfs_is_chardev_opts_argv (guestfs_h *g,
const char *path,
const struct guestfs_is_chardev_opts_argv *optargs);
This is the "argv variant" of "guestfs_is_chardev_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_config
int
guestfs_is_config (guestfs_h *g);
This returns true iff this handle is being configured (in the "CONFIG" state).
For more information on states, see guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.0.2)
guestfs_is_dir
int
guestfs_is_dir (guestfs_h *g,
const char *path);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_is_dir_opts" with no optional arguments.
(Added in 0.8)
guestfs_is_dir_opts
int
guestfs_is_dir_opts (guestfs_h *g,
const char *path,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_IS_DIR_OPTS_FOLLOWSYMLINKS, int followsymlinks,
This returns "true" if and only if there is a directory with the given "path" name. Note that it returns
false for other objects like files.
If the optional flag "followsymlinks" is true, then a symlink (or chain of symlinks) that ends with a
directory also causes the function to return true.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.23.4)
guestfs_is_dir_opts_va
int
guestfs_is_dir_opts_va (guestfs_h *g,
const char *path,
va_list args);
This is the "va_list variant" of "guestfs_is_dir_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_dir_opts_argv
int
guestfs_is_dir_opts_argv (guestfs_h *g,
const char *path,
const struct guestfs_is_dir_opts_argv *optargs);
This is the "argv variant" of "guestfs_is_dir_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_fifo
int
guestfs_is_fifo (guestfs_h *g,
const char *path);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_is_fifo_opts" with no optional arguments.
(Added in 1.5.10)
guestfs_is_fifo_opts
int
guestfs_is_fifo_opts (guestfs_h *g,
const char *path,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_IS_FIFO_OPTS_FOLLOWSYMLINKS, int followsymlinks,
This returns "true" if and only if there is a FIFO (named pipe) with the given "path" name.
If the optional flag "followsymlinks" is true, then a symlink (or chain of symlinks) that ends with a
FIFO also causes the function to return true.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.23.4)
guestfs_is_fifo_opts_va
int
guestfs_is_fifo_opts_va (guestfs_h *g,
const char *path,
va_list args);
This is the "va_list variant" of "guestfs_is_fifo_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_fifo_opts_argv
int
guestfs_is_fifo_opts_argv (guestfs_h *g,
const char *path,
const struct guestfs_is_fifo_opts_argv *optargs);
This is the "argv variant" of "guestfs_is_fifo_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_file
int
guestfs_is_file (guestfs_h *g,
const char *path);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_is_file_opts" with no optional arguments.
(Added in 0.8)
guestfs_is_file_opts
int
guestfs_is_file_opts (guestfs_h *g,
const char *path,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_IS_FILE_OPTS_FOLLOWSYMLINKS, int followsymlinks,
This returns "true" if and only if there is a regular file with the given "path" name. Note that it
returns false for other objects like directories.
If the optional flag "followsymlinks" is true, then a symlink (or chain of symlinks) that ends with a
file also causes the function to return true.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.23.4)
guestfs_is_file_opts_va
int
guestfs_is_file_opts_va (guestfs_h *g,
const char *path,
va_list args);
This is the "va_list variant" of "guestfs_is_file_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_file_opts_argv
int
guestfs_is_file_opts_argv (guestfs_h *g,
const char *path,
const struct guestfs_is_file_opts_argv *optargs);
This is the "argv variant" of "guestfs_is_file_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_launching
int
guestfs_is_launching (guestfs_h *g);
This returns true iff this handle is launching the subprocess (in the "LAUNCHING" state).
For more information on states, see guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.0.2)
guestfs_is_lv
int
guestfs_is_lv (guestfs_h *g,
const char *device);
This command tests whether "device" is a logical volume, and returns true iff this is the case.
This function returns a C truth value on success or -1 on error.
(Added in 1.5.3)
guestfs_is_ready
int
guestfs_is_ready (guestfs_h *g);
This returns true iff this handle is ready to accept commands (in the "READY" state).
For more information on states, see guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.0.2)
guestfs_is_socket
int
guestfs_is_socket (guestfs_h *g,
const char *path);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_is_socket_opts" with no optional arguments.
(Added in 1.5.10)
guestfs_is_socket_opts
int
guestfs_is_socket_opts (guestfs_h *g,
const char *path,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_IS_SOCKET_OPTS_FOLLOWSYMLINKS, int followsymlinks,
This returns "true" if and only if there is a Unix domain socket with the given "path" name.
If the optional flag "followsymlinks" is true, then a symlink (or chain of symlinks) that ends with a
socket also causes the function to return true.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.23.4)
guestfs_is_socket_opts_va
int
guestfs_is_socket_opts_va (guestfs_h *g,
const char *path,
va_list args);
This is the "va_list variant" of "guestfs_is_socket_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_socket_opts_argv
int
guestfs_is_socket_opts_argv (guestfs_h *g,
const char *path,
const struct guestfs_is_socket_opts_argv *optargs);
This is the "argv variant" of "guestfs_is_socket_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_is_symlink
int
guestfs_is_symlink (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a symbolic link with the given "path" name.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.5.10)
guestfs_is_whole_device
int
guestfs_is_whole_device (guestfs_h *g,
const char *device);
This returns "true" if and only if "device" refers to a whole block device. That is, not a partition or a
logical device.
This function returns a C truth value on success or -1 on error.
(Added in 1.21.9)
guestfs_is_zero
int
guestfs_is_zero (guestfs_h *g,
const char *path);
This returns true iff the file exists and the file is empty or it contains all zero bytes.
This function returns a C truth value on success or -1 on error.
(Added in 1.11.8)
guestfs_is_zero_device
int
guestfs_is_zero_device (guestfs_h *g,
const char *device);
This returns true iff the device exists and contains all zero bytes.
Note that for large devices this can take a long time to run.
This function returns a C truth value on success or -1 on error.
(Added in 1.11.8)
guestfs_isoinfo
struct guestfs_isoinfo *
guestfs_isoinfo (guestfs_h *g,
const char *isofile);
This is the same as "guestfs_isoinfo_device" except that it works for an ISO file located inside some
other mounted filesystem. Note that in the common case where you have added an ISO file as a libguestfs
device, you would not call this. Instead you would call "guestfs_isoinfo_device".
This function returns a "struct guestfs_isoinfo *", or NULL if there was an error. The caller must call
"guestfs_free_isoinfo" after use.
(Added in 1.17.19)
guestfs_isoinfo_device
struct guestfs_isoinfo *
guestfs_isoinfo_device (guestfs_h *g,
const char *device);
"device" is an ISO device. This returns a struct of information read from the primary volume descriptor
(the ISO equivalent of the superblock) of the device.
Usually it is more efficient to use the isoinfo(1) command with the -d option on the host to analyze ISO
files, instead of going through libguestfs.
For information on the primary volume descriptor fields, see
http://wiki.osdev.org/ISO_9660#The_Primary_Volume_Descriptor
This function returns a "struct guestfs_isoinfo *", or NULL if there was an error. The caller must call
"guestfs_free_isoinfo" after use.
(Added in 1.17.19)
guestfs_journal_close
int
guestfs_journal_close (guestfs_h *g);
Close the journal handle.
This function returns 0 on success or -1 on error.
(Added in 1.23.11)
guestfs_journal_get
struct guestfs_xattr_list *
guestfs_journal_get (guestfs_h *g);
Read the current journal entry. This returns all the fields in the journal as a set of "(attrname,
attrval)" pairs. The "attrname" is the field name (a string).
The "attrval" is the field value (a binary blob, often but not always a string). Please note that
"attrval" is a byte array, not a \0-terminated C string.
The length of data may be truncated to the data threshold (see: "guestfs_journal_set_data_threshold",
"guestfs_journal_get_data_threshold").
If you set the data threshold to unlimited (0) then this call can read a journal entry of any size, ie.
it is not limited by the libguestfs protocol.
This function returns a "struct guestfs_xattr_list *", or NULL if there was an error. The caller must
call "guestfs_free_xattr_list" after use.
(Added in 1.23.11)
guestfs_journal_get_data_threshold
int64_t
guestfs_journal_get_data_threshold (guestfs_h *g);
Get the current data threshold for reading journal entries. This is a hint to the journal that it may
truncate data fields to this size when reading them (note also that it may not truncate them). If this
returns 0, then the threshold is unlimited.
See also "guestfs_journal_set_data_threshold".
On error this function returns -1.
(Added in 1.23.11)
guestfs_journal_next
int
guestfs_journal_next (guestfs_h *g);
Move to the next journal entry. You have to call this at least once after opening the handle before you
are able to read data.
The returned boolean tells you if there are any more journal records to read. "true" means you can read
the next record (eg. using "guestfs_journal_get_data"), and "false" means you have reached the end of the
journal.
This function returns a C truth value on success or -1 on error.
(Added in 1.23.11)
guestfs_journal_open
int
guestfs_journal_open (guestfs_h *g,
const char *directory);
Open the systemd journal located in "directory". Any previously opened journal handle is closed.
The contents of the journal can be read using "guestfs_journal_next" and "guestfs_journal_get".
After you have finished using the journal, you should close the handle by calling
"guestfs_journal_close".
This function returns 0 on success or -1 on error.
(Added in 1.23.11)
guestfs_journal_set_data_threshold
int
guestfs_journal_set_data_threshold (guestfs_h *g,
int64_t threshold);
Set the data threshold for reading journal entries. This is a hint to the journal that it may truncate
data fields to this size when reading them (note also that it may not truncate them). If you set this to
0, then the threshold is unlimited.
See also "guestfs_journal_get_data_threshold".
This function returns 0 on success or -1 on error.
(Added in 1.23.11)
guestfs_journal_skip
int64_t
guestfs_journal_skip (guestfs_h *g,
int64_t skip);
Skip forwards ("skip ≥ 0") or backwards ("skip < 0") in the journal.
The number of entries actually skipped is returned (note "rskip ≥ 0"). If this is not the same as the
absolute value of the skip parameter ("|skip|") you passed in then it means you have reached the end or
the start of the journal.
On error this function returns -1.
(Added in 1.23.11)
guestfs_kill_subprocess
int
guestfs_kill_subprocess (guestfs_h *g);
This function is deprecated. In new code, use the "guestfs_shutdown" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This kills the hypervisor.
Do not call this. See: "guestfs_shutdown" instead.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_launch
int
guestfs_launch (guestfs_h *g);
You should call this after configuring the handle (eg. adding drives) but before performing any actions.
Do not call "guestfs_launch" twice on the same handle. Although it will not give an error (for
historical reasons), the precise behaviour when you do this is not well defined. Handles are very cheap
to create, so create a new one for each launch.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 0.3)
guestfs_lchown
int
guestfs_lchown (guestfs_h *g,
int owner,
int group,
const char *path);
Change the file owner to "owner" and group to "group". This is like "guestfs_chown" but if "path" is a
symlink then the link itself is changed, not the target.
Only numeric uid and gid are supported. If you want to use names, you will need to locate and parse the
password file yourself (Augeas support makes this relatively easy).
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_ldmtool_create_all
int
guestfs_ldmtool_create_all (guestfs_h *g);
This function scans all block devices looking for Windows dynamic disk volumes and partitions, and
creates devices for any that were found.
Call "guestfs_list_ldm_volumes" and "guestfs_list_ldm_partitions" to return all devices.
Note that you don't normally need to call this explicitly, since it is done automatically at
"guestfs_launch" time. However you might want to call this function if you have hotplugged disks or have
just created a Windows dynamic disk.
This function returns 0 on success or -1 on error.
(Added in 1.20.0)
guestfs_ldmtool_diskgroup_disks
char **
guestfs_ldmtool_diskgroup_disks (guestfs_h *g,
const char *diskgroup);
Return the disks in a Windows dynamic disk group. The "diskgroup" parameter should be the GUID of a disk
group, one element from the list returned by "guestfs_ldmtool_scan".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.20.0)
guestfs_ldmtool_diskgroup_name
char *
guestfs_ldmtool_diskgroup_name (guestfs_h *g,
const char *diskgroup);
Return the name of a Windows dynamic disk group. The "diskgroup" parameter should be the GUID of a disk
group, one element from the list returned by "guestfs_ldmtool_scan".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.20.0)
guestfs_ldmtool_diskgroup_volumes
char **
guestfs_ldmtool_diskgroup_volumes (guestfs_h *g,
const char *diskgroup);
Return the volumes in a Windows dynamic disk group. The "diskgroup" parameter should be the GUID of a
disk group, one element from the list returned by "guestfs_ldmtool_scan".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.20.0)
guestfs_ldmtool_remove_all
int
guestfs_ldmtool_remove_all (guestfs_h *g);
This is essentially the opposite of "guestfs_ldmtool_create_all". It removes the device mapper mappings
for all Windows dynamic disk volumes
This function returns 0 on success or -1 on error.
(Added in 1.20.0)
guestfs_ldmtool_scan
char **
guestfs_ldmtool_scan (guestfs_h *g);
This function scans for Windows dynamic disks. It returns a list of identifiers (GUIDs) for all disk
groups that were found. These identifiers can be passed to other "guestfs_ldmtool_*" functions.
This function scans all block devices. To scan a subset of block devices, call
"guestfs_ldmtool_scan_devices" instead.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.20.0)
guestfs_ldmtool_scan_devices
char **
guestfs_ldmtool_scan_devices (guestfs_h *g,
char *const *devices);
This function scans for Windows dynamic disks. It returns a list of identifiers (GUIDs) for all disk
groups that were found. These identifiers can be passed to other "guestfs_ldmtool_*" functions.
The parameter "devices" is a list of block devices which are scanned. If this list is empty, all block
devices are scanned.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.20.0)
guestfs_ldmtool_volume_hint
char *
guestfs_ldmtool_volume_hint (guestfs_h *g,
const char *diskgroup,
const char *volume);
Return the hint field of the volume named "volume" in the disk group with GUID "diskgroup". This may not
be defined, in which case the empty string is returned. The hint field is often, though not always, the
name of a Windows drive, eg. "E:".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.20.0)
guestfs_ldmtool_volume_partitions
char **
guestfs_ldmtool_volume_partitions (guestfs_h *g,
const char *diskgroup,
const char *volume);
Return the list of partitions in the volume named "volume" in the disk group with GUID "diskgroup".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.20.0)
guestfs_ldmtool_volume_type
char *
guestfs_ldmtool_volume_type (guestfs_h *g,
const char *diskgroup,
const char *volume);
Return the type of the volume named "volume" in the disk group with GUID "diskgroup".
Possible volume types that can be returned here include: "simple", "spanned", "striped", "mirrored",
"raid5". Other types may also be returned.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.20.0)
guestfs_lgetxattr
char *
guestfs_lgetxattr (guestfs_h *g,
const char *path,
const char *name,
size_t *size_r);
Get a single extended attribute from file "path" named "name". If "path" is a symlink, then this call
returns an extended attribute from the symlink.
Normally it is better to get all extended attributes from a file in one go by calling
"guestfs_getxattrs". However some Linux filesystem implementations are buggy and do not provide a way to
list out attributes. For these filesystems (notably ntfs-3g) you have to know the names of the extended
attributes you want in advance and call this function.
Extended attribute values are blobs of binary data. If there is no extended attribute named "name", this
returns an error.
See also: "guestfs_lgetxattrs", "guestfs_getxattr", attr(5).
This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r.
The caller must free the returned buffer after use.
(Added in 1.7.24)
guestfs_lgetxattrs
struct guestfs_xattr_list *
guestfs_lgetxattrs (guestfs_h *g,
const char *path);
This is the same as "guestfs_getxattrs", but if "path" is a symbolic link, then it returns the extended
attributes of the link itself.
This function returns a "struct guestfs_xattr_list *", or NULL if there was an error. The caller must
call "guestfs_free_xattr_list" after use.
(Added in 1.0.59)
guestfs_list_9p
char **
guestfs_list_9p (guestfs_h *g);
List all 9p filesystems attached to the guest. A list of mount tags is returned.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.11.12)
guestfs_list_devices
char **
guestfs_list_devices (guestfs_h *g);
List all the block devices.
The full block device names are returned, eg. "/dev/sda".
See also "guestfs_list_filesystems".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.4)
guestfs_list_disk_labels
char **
guestfs_list_disk_labels (guestfs_h *g);
If you add drives using the optional "label" parameter of "guestfs_add_drive_opts", you can use this call
to map between disk labels, and raw block device and partition names (like "/dev/sda" and "/dev/sda1").
This returns a hashtable, where keys are the disk labels (without the "/dev/disk/guestfs" prefix), and
the values are the full raw block device and partition names (eg. "/dev/sda" and "/dev/sda1").
This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of
strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing
NULL entry. The caller must free the strings and the array after use.
(Added in 1.19.49)
guestfs_list_dm_devices
char **
guestfs_list_dm_devices (guestfs_h *g);
List all device mapper devices.
The returned list contains "/dev/mapper/*" devices, eg. ones created by a previous call to
"guestfs_luks_open".
Device mapper devices which correspond to logical volumes are not returned in this list. Call
"guestfs_lvs" if you want to list logical volumes.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.11.15)
guestfs_list_filesystems
char **
guestfs_list_filesystems (guestfs_h *g);
This inspection command looks for filesystems on partitions, block devices and logical volumes, returning
a list of "mountables" containing filesystems and their type.
The return value is a hash, where the keys are the devices containing filesystems, and the values are the
filesystem types. For example:
"/dev/sda1" => "ntfs"
"/dev/sda2" => "ext2"
"/dev/vg_guest/lv_root" => "ext4"
"/dev/vg_guest/lv_swap" => "swap"
The key is not necessarily a block device. It may also be an opaque 'mountable' string which can be
passed to "guestfs_mount".
The value can have the special value "unknown", meaning the content of the device is undetermined or
empty. "swap" means a Linux swap partition.
This command runs other libguestfs commands, which might include "guestfs_mount" and "guestfs_umount",
and therefore you should use this soon after launch and only when nothing is mounted.
Not all of the filesystems returned will be mountable. In particular, swap partitions are returned in
the list. Also this command does not check that each filesystem found is valid and mountable, and some
filesystems might be mountable but require special options. Filesystems may not all belong to a single
logical operating system (use "guestfs_inspect_os" to look for OSes).
This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of
strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing
NULL entry. The caller must free the strings and the array after use.
(Added in 1.5.15)
guestfs_list_ldm_partitions
char **
guestfs_list_ldm_partitions (guestfs_h *g);
This function returns all Windows dynamic disk partitions that were found at launch time. It returns a
list of device names.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.20.0)
guestfs_list_ldm_volumes
char **
guestfs_list_ldm_volumes (guestfs_h *g);
This function returns all Windows dynamic disk volumes that were found at launch time. It returns a list
of device names.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.20.0)
guestfs_list_md_devices
char **
guestfs_list_md_devices (guestfs_h *g);
List all Linux md devices.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.15.4)
guestfs_list_partitions
char **
guestfs_list_partitions (guestfs_h *g);
List all the partitions detected on all block devices.
The full partition device names are returned, eg. "/dev/sda1"
This does not return logical volumes. For that you will need to call "guestfs_lvs".
See also "guestfs_list_filesystems".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.4)
guestfs_ll
char *
guestfs_ll (guestfs_h *g,
const char *directory);
List the files in "directory" (relative to the root directory, there is no cwd) in the format of 'ls
-la'.
This command is mostly useful for interactive sessions. It is not intended that you try to parse the
output string.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 0.4)
guestfs_llz
char *
guestfs_llz (guestfs_h *g,
const char *directory);
List the files in "directory" in the format of 'ls -laZ'.
This command is mostly useful for interactive sessions. It is not intended that you try to parse the
output string.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.17.6)
guestfs_ln
int
guestfs_ln (guestfs_h *g,
const char *target,
const char *linkname);
This command creates a hard link using the "ln" command.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_ln_f
int
guestfs_ln_f (guestfs_h *g,
const char *target,
const char *linkname);
This command creates a hard link using the "ln -f" command. The -f option removes the link ("linkname")
if it exists already.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_ln_s
int
guestfs_ln_s (guestfs_h *g,
const char *target,
const char *linkname);
This command creates a symbolic link using the "ln -s" command.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_ln_sf
int
guestfs_ln_sf (guestfs_h *g,
const char *target,
const char *linkname);
This command creates a symbolic link using the "ln -sf" command, The -f option removes the link
("linkname") if it exists already.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_lremovexattr
int
guestfs_lremovexattr (guestfs_h *g,
const char *xattr,
const char *path);
This is the same as "guestfs_removexattr", but if "path" is a symbolic link, then it removes an extended
attribute of the link itself.
This function returns 0 on success or -1 on error.
(Added in 1.0.59)
guestfs_ls
char **
guestfs_ls (guestfs_h *g,
const char *directory);
List the files in "directory" (relative to the root directory, there is no cwd). The '.' and '..'
entries are not returned, but hidden files are shown.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.4)
guestfs_ls0
int
guestfs_ls0 (guestfs_h *g,
const char *dir,
const char *filenames);
This specialized command is used to get a listing of the filenames in the directory "dir". The list of
filenames is written to the local file "filenames" (on the host).
In the output file, the filenames are separated by "\0" characters.
"." and ".." are not returned. The filenames are not sorted.
This function returns 0 on success or -1 on error.
(Added in 1.19.32)
guestfs_lsetxattr
int
guestfs_lsetxattr (guestfs_h *g,
const char *xattr,
const char *val,
int vallen,
const char *path);
This is the same as "guestfs_setxattr", but if "path" is a symbolic link, then it sets an extended
attribute of the link itself.
This function returns 0 on success or -1 on error.
(Added in 1.0.59)
guestfs_lstat
struct guestfs_stat *
guestfs_lstat (guestfs_h *g,
const char *path);
Returns file information for the given "path".
This is the same as "guestfs_stat" except that if "path" is a symbolic link, then the link is stat-ed,
not the file it refers to.
This is the same as the lstat(2) system call.
This function returns a "struct guestfs_stat *", or NULL if there was an error. The caller must call
"guestfs_free_stat" after use.
(Added in 0.9.2)
guestfs_lstatlist
struct guestfs_stat_list *
guestfs_lstatlist (guestfs_h *g,
const char *path,
char *const *names);
This call allows you to perform the "guestfs_lstat" operation on multiple files, where all files are in
the directory "path". "names" is the list of files from this directory.
On return you get a list of stat structs, with a one-to-one correspondence to the "names" list. If any
name did not exist or could not be lstat'd, then the "ino" field of that structure is set to "-1".
This call is intended for programs that want to efficiently list a directory contents without making many
round-trips. See also "guestfs_lxattrlist" for a similarly efficient call for getting extended
attributes.
This function returns a "struct guestfs_stat_list *", or NULL if there was an error. The caller must
call "guestfs_free_stat_list" after use.
(Added in 1.0.77)
guestfs_luks_add_key
int
guestfs_luks_add_key (guestfs_h *g,
const char *device,
const char *key,
const char *newkey,
int keyslot);
This command adds a new key on LUKS device "device". "key" is any existing key, and is used to access
the device. "newkey" is the new key to add. "keyslot" is the key slot that will be replaced.
Note that if "keyslot" already contains a key, then this command will fail. You have to use
"guestfs_luks_kill_slot" first to remove that key.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive material. Read the
section "KEYS AND PASSPHRASES" for more information.
(Added in 1.5.2)
guestfs_luks_close
int
guestfs_luks_close (guestfs_h *g,
const char *device);
This closes a LUKS device that was created earlier by "guestfs_luks_open" or "guestfs_luks_open_ro". The
"device" parameter must be the name of the LUKS mapping device (ie. "/dev/mapper/mapname") and not the
name of the underlying block device.
This function returns 0 on success or -1 on error.
(Added in 1.5.1)
guestfs_luks_format
int
guestfs_luks_format (guestfs_h *g,
const char *device,
const char *key,
int keyslot);
This command erases existing data on "device" and formats the device as a LUKS encrypted device. "key"
is the initial key, which is added to key slot "slot". (LUKS supports 8 key slots, numbered 0-7).
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive material. Read the
section "KEYS AND PASSPHRASES" for more information.
(Added in 1.5.2)
guestfs_luks_format_cipher
int
guestfs_luks_format_cipher (guestfs_h *g,
const char *device,
const char *key,
int keyslot,
const char *cipher);
This command is the same as "guestfs_luks_format" but it also allows you to set the "cipher" used.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive material. Read the
section "KEYS AND PASSPHRASES" for more information.
(Added in 1.5.2)
guestfs_luks_kill_slot
int
guestfs_luks_kill_slot (guestfs_h *g,
const char *device,
const char *key,
int keyslot);
This command deletes the key in key slot "keyslot" from the encrypted LUKS device "device". "key" must
be one of the other keys.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive material. Read the
section "KEYS AND PASSPHRASES" for more information.
(Added in 1.5.2)
guestfs_luks_open
int
guestfs_luks_open (guestfs_h *g,
const char *device,
const char *key,
const char *mapname);
This command opens a block device which has been encrypted according to the Linux Unified Key Setup
(LUKS) standard.
"device" is the encrypted block device or partition.
The caller must supply one of the keys associated with the LUKS block device, in the "key" parameter.
This creates a new block device called "/dev/mapper/mapname". Reads and writes to this block device are
decrypted from and encrypted to the underlying "device" respectively.
If this block device contains LVM volume groups, then calling "guestfs_vgscan" followed by
"guestfs_vg_activate_all" will make them visible.
Use "guestfs_list_dm_devices" to list all device mapper devices.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive material. Read the
section "KEYS AND PASSPHRASES" for more information.
(Added in 1.5.1)
guestfs_luks_open_ro
int
guestfs_luks_open_ro (guestfs_h *g,
const char *device,
const char *key,
const char *mapname);
This is the same as "guestfs_luks_open" except that a read-only mapping is created.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive material. Read the
section "KEYS AND PASSPHRASES" for more information.
(Added in 1.5.1)
guestfs_lvcreate
int
guestfs_lvcreate (guestfs_h *g,
const char *logvol,
const char *volgroup,
int mbytes);
This creates an LVM logical volume called "logvol" on the volume group "volgroup", with "size" megabytes.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_lvcreate_free
int
guestfs_lvcreate_free (guestfs_h *g,
const char *logvol,
const char *volgroup,
int percent);
Create an LVM logical volume called "/dev/volgroup/logvol", using approximately "percent" % of the free
space remaining in the volume group. Most usefully, when "percent" is 100 this will create the largest
possible LV.
This function returns 0 on success or -1 on error.
(Added in 1.17.18)
guestfs_lvm_canonical_lv_name
char *
guestfs_lvm_canonical_lv_name (guestfs_h *g,
const char *lvname);
This converts alternative naming schemes for LVs that you might find to the canonical name. For example,
"/dev/mapper/VG-LV" is converted to "/dev/VG/LV".
This command returns an error if the "lvname" parameter does not refer to a logical volume.
See also "guestfs_is_lv", "guestfs_canonical_device_name".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.24)
guestfs_lvm_clear_filter
int
guestfs_lvm_clear_filter (guestfs_h *g);
This undoes the effect of "guestfs_lvm_set_filter". LVM will be able to see every block device.
This command also clears the LVM cache and performs a volume group scan.
This function returns 0 on success or -1 on error.
(Added in 1.5.1)
guestfs_lvm_remove_all
int
guestfs_lvm_remove_all (guestfs_h *g);
This command removes all LVM logical volumes, volume groups and physical volumes.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_lvm_set_filter
int
guestfs_lvm_set_filter (guestfs_h *g,
char *const *devices);
This sets the LVM device filter so that LVM will only be able to "see" the block devices in the list
"devices", and will ignore all other attached block devices.
Where disk image(s) contain duplicate PVs or VGs, this command is useful to get LVM to ignore the
duplicates, otherwise LVM can get confused. Note also there are two types of duplication possible:
either cloned PVs/VGs which have identical UUIDs; or VGs that are not cloned but just happen to have the
same name. In normal operation you cannot create this situation, but you can do it outside LVM, eg. by
cloning disk images or by bit twiddling inside the LVM metadata.
This command also clears the LVM cache and performs a volume group scan.
You can filter whole block devices or individual partitions.
You cannot use this if any VG is currently in use (eg. contains a mounted filesystem), even if you are
not filtering out that VG.
This function returns 0 on success or -1 on error.
(Added in 1.5.1)
guestfs_lvremove
int
guestfs_lvremove (guestfs_h *g,
const char *device);
Remove an LVM logical volume "device", where "device" is the path to the LV, such as "/dev/VG/LV".
You can also remove all LVs in a volume group by specifying the VG name, "/dev/VG".
This function returns 0 on success or -1 on error.
(Added in 1.0.13)
guestfs_lvrename
int
guestfs_lvrename (guestfs_h *g,
const char *logvol,
const char *newlogvol);
Rename a logical volume "logvol" with the new name "newlogvol".
This function returns 0 on success or -1 on error.
(Added in 1.0.83)
guestfs_lvresize
int
guestfs_lvresize (guestfs_h *g,
const char *device,
int mbytes);
This resizes (expands or shrinks) an existing LVM logical volume to "mbytes". When reducing, data in the
reduced part is lost.
This function returns 0 on success or -1 on error.
(Added in 1.0.27)
guestfs_lvresize_free
int
guestfs_lvresize_free (guestfs_h *g,
const char *lv,
int percent);
This expands an existing logical volume "lv" so that it fills "pc"% of the remaining free space in the
volume group. Commonly you would call this with pc = 100 which expands the logical volume as much as
possible, using all remaining free space in the volume group.
This function returns 0 on success or -1 on error.
(Added in 1.3.3)
guestfs_lvs
char **
guestfs_lvs (guestfs_h *g);
List all the logical volumes detected. This is the equivalent of the lvs(8) command.
This returns a list of the logical volume device names (eg. "/dev/VolGroup00/LogVol00").
See also "guestfs_lvs_full", "guestfs_list_filesystems".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.4)
guestfs_lvs_full
struct guestfs_lvm_lv_list *
guestfs_lvs_full (guestfs_h *g);
List all the logical volumes detected. This is the equivalent of the lvs(8) command. The "full" version
includes all fields.
This function returns a "struct guestfs_lvm_lv_list *", or NULL if there was an error. The caller must
call "guestfs_free_lvm_lv_list" after use.
(Added in 0.4)
guestfs_lvuuid
char *
guestfs_lvuuid (guestfs_h *g,
const char *device);
This command returns the UUID of the LVM LV "device".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.87)
guestfs_lxattrlist
struct guestfs_xattr_list *
guestfs_lxattrlist (guestfs_h *g,
const char *path,
char *const *names);
This call allows you to get the extended attributes of multiple files, where all files are in the
directory "path". "names" is the list of files from this directory.
On return you get a flat list of xattr structs which must be interpreted sequentially. The first xattr
struct always has a zero-length "attrname". "attrval" in this struct is zero-length to indicate there
was an error doing "lgetxattr" for this file, or is a C string which is a decimal number (the number of
following attributes for this file, which could be "0"). Then after the first xattr struct are the zero
or more attributes for the first named file. This repeats for the second and subsequent files.
This call is intended for programs that want to efficiently list a directory contents without making many
round-trips. See also "guestfs_lstatlist" for a similarly efficient call for getting standard stats.
This function returns a "struct guestfs_xattr_list *", or NULL if there was an error. The caller must
call "guestfs_free_xattr_list" after use.
(Added in 1.0.77)
guestfs_max_disks
int
guestfs_max_disks (guestfs_h *g);
Return the maximum number of disks that may be added to a handle (eg. by "guestfs_add_drive_opts" and
similar calls).
This function was added in libguestfs 1.19.7. In previous versions of libguestfs the limit was 25.
See "MAXIMUM NUMBER OF DISKS" in guestfs(3) for additional information on this topic.
On error this function returns -1.
(Added in 1.19.7)
guestfs_md_create
int
guestfs_md_create (guestfs_h *g,
const char *name,
char *const *devices,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MD_CREATE_MISSINGBITMAP, int64_t missingbitmap,
GUESTFS_MD_CREATE_NRDEVICES, int nrdevices,
GUESTFS_MD_CREATE_SPARE, int spare,
GUESTFS_MD_CREATE_CHUNK, int64_t chunk,
GUESTFS_MD_CREATE_LEVEL, const char *level,
Create a Linux md (RAID) device named "name" on the devices in the list "devices".
The optional parameters are:
"missingbitmap"
A bitmap of missing devices. If a bit is set it means that a missing device is added to the array.
The least significant bit corresponds to the first device in the array.
As examples:
If "devices = ["/dev/sda"]" and "missingbitmap = 0x1" then the resulting array would be "[<missing>,
"/dev/sda"]".
If "devices = ["/dev/sda"]" and "missingbitmap = 0x2" then the resulting array would be "["/dev/sda",
<missing>]".
This defaults to 0 (no missing devices).
The length of "devices" + the number of bits set in "missingbitmap" must equal "nrdevices" + "spare".
"nrdevices"
The number of active RAID devices.
If not set, this defaults to the length of "devices" plus the number of bits set in "missingbitmap".
"spare"
The number of spare devices.
If not set, this defaults to 0.
"chunk"
The chunk size in bytes.
"level"
The RAID level, which can be one of: linear, raid0, 0, stripe, raid1, 1, mirror, raid4, 4, raid5, 5,
raid6, 6, raid10, 10. Some of these are synonymous, and more levels may be added in future.
If not set, this defaults to "raid1".
This function returns 0 on success or -1 on error.
(Added in 1.15.6)
guestfs_md_create_va
int
guestfs_md_create_va (guestfs_h *g,
const char *name,
char *const *devices,
va_list args);
This is the "va_list variant" of "guestfs_md_create".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_md_create_argv
int
guestfs_md_create_argv (guestfs_h *g,
const char *name,
char *const *devices,
const struct guestfs_md_create_argv *optargs);
This is the "argv variant" of "guestfs_md_create".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_md_detail
char **
guestfs_md_detail (guestfs_h *g,
const char *md);
This command exposes the output of 'mdadm -DY <md>'. The following fields are usually present in the
returned hash. Other fields may also be present.
"level"
The raid level of the MD device.
"devices"
The number of underlying devices in the MD device.
"metadata"
The metadata version used.
"uuid"
The UUID of the MD device.
"name"
The name of the MD device.
This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of
strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing
NULL entry. The caller must free the strings and the array after use.
(Added in 1.15.6)
guestfs_md_stat
struct guestfs_mdstat_list *
guestfs_md_stat (guestfs_h *g,
const char *md);
This call returns a list of the underlying devices which make up the single software RAID array device
"md".
To get a list of software RAID devices, call "guestfs_list_md_devices".
Each structure returned corresponds to one device along with additional status information:
"mdstat_device"
The name of the underlying device.
"mdstat_index"
The index of this device within the array.
"mdstat_flags"
Flags associated with this device. This is a string containing (in no specific order) zero or more
of the following flags:
"W" write-mostly
"F" device is faulty
"S" device is a RAID spare
"R" replacement
This function returns a "struct guestfs_mdstat_list *", or NULL if there was an error. The caller must
call "guestfs_free_mdstat_list" after use.
(Added in 1.17.21)
guestfs_md_stop
int
guestfs_md_stop (guestfs_h *g,
const char *md);
This command deactivates the MD array named "md". The device is stopped, but it is not destroyed or
zeroed.
This function returns 0 on success or -1 on error.
(Added in 1.15.6)
guestfs_mkdir
int
guestfs_mkdir (guestfs_h *g,
const char *path);
Create a directory named "path".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_mkdir_mode
int
guestfs_mkdir_mode (guestfs_h *g,
const char *path,
int mode);
This command creates a directory, setting the initial permissions of the directory to "mode".
For common Linux filesystems, the actual mode which is set will be "mode & ~umask & 01777". Non-native-
Linux filesystems may interpret the mode in other ways.
See also "guestfs_mkdir", "guestfs_umask"
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_mkdir_p
int
guestfs_mkdir_p (guestfs_h *g,
const char *path);
Create a directory named "path", creating any parent directories as necessary. This is like the "mkdir
-p" shell command.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_mkdtemp
char *
guestfs_mkdtemp (guestfs_h *g,
const char *tmpl);
This command creates a temporary directory. The "tmpl" parameter should be a full pathname for the
temporary directory name with the final six characters being "XXXXXX".
For example: "/tmp/myprogXXXXXX" or "/Temp/myprogXXXXXX", the second one being suitable for Windows
filesystems.
The name of the temporary directory that was created is returned.
The temporary directory is created with mode 0700 and is owned by root.
The caller is responsible for deleting the temporary directory and its contents after use.
See also: mkdtemp(3)
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.54)
guestfs_mke2fs
int
guestfs_mke2fs (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MKE2FS_BLOCKSCOUNT, int64_t blockscount,
GUESTFS_MKE2FS_BLOCKSIZE, int64_t blocksize,
GUESTFS_MKE2FS_FRAGSIZE, int64_t fragsize,
GUESTFS_MKE2FS_BLOCKSPERGROUP, int64_t blockspergroup,
GUESTFS_MKE2FS_NUMBEROFGROUPS, int64_t numberofgroups,
GUESTFS_MKE2FS_BYTESPERINODE, int64_t bytesperinode,
GUESTFS_MKE2FS_INODESIZE, int64_t inodesize,
GUESTFS_MKE2FS_JOURNALSIZE, int64_t journalsize,
GUESTFS_MKE2FS_NUMBEROFINODES, int64_t numberofinodes,
GUESTFS_MKE2FS_STRIDESIZE, int64_t stridesize,
GUESTFS_MKE2FS_STRIPEWIDTH, int64_t stripewidth,
GUESTFS_MKE2FS_MAXONLINERESIZE, int64_t maxonlineresize,
GUESTFS_MKE2FS_RESERVEDBLOCKSPERCENTAGE, int reservedblockspercentage,
GUESTFS_MKE2FS_MMPUPDATEINTERVAL, int mmpupdateinterval,
GUESTFS_MKE2FS_JOURNALDEVICE, const char *journaldevice,
GUESTFS_MKE2FS_LABEL, const char *label,
GUESTFS_MKE2FS_LASTMOUNTEDDIR, const char *lastmounteddir,
GUESTFS_MKE2FS_CREATOROS, const char *creatoros,
GUESTFS_MKE2FS_FSTYPE, const char *fstype,
GUESTFS_MKE2FS_USAGETYPE, const char *usagetype,
GUESTFS_MKE2FS_UUID, const char *uuid,
GUESTFS_MKE2FS_FORCECREATE, int forcecreate,
GUESTFS_MKE2FS_WRITESBANDGROUPONLY, int writesbandgrouponly,
GUESTFS_MKE2FS_LAZYITABLEINIT, int lazyitableinit,
GUESTFS_MKE2FS_LAZYJOURNALINIT, int lazyjournalinit,
GUESTFS_MKE2FS_TESTFS, int testfs,
GUESTFS_MKE2FS_DISCARD, int discard,
GUESTFS_MKE2FS_QUOTATYPE, int quotatype,
GUESTFS_MKE2FS_EXTENT, int extent,
GUESTFS_MKE2FS_FILETYPE, int filetype,
GUESTFS_MKE2FS_FLEXBG, int flexbg,
GUESTFS_MKE2FS_HASJOURNAL, int hasjournal,
GUESTFS_MKE2FS_JOURNALDEV, int journaldev,
GUESTFS_MKE2FS_LARGEFILE, int largefile,
GUESTFS_MKE2FS_QUOTA, int quota,
GUESTFS_MKE2FS_RESIZEINODE, int resizeinode,
GUESTFS_MKE2FS_SPARSESUPER, int sparsesuper,
GUESTFS_MKE2FS_UNINITBG, int uninitbg,
"mke2fs" is used to create an ext2, ext3, or ext4 filesystem on "device".
The optional "blockscount" is the size of the filesystem in blocks. If omitted it defaults to the size
of "device". Note if the filesystem is too small to contain a journal, "mke2fs" will silently create an
ext2 filesystem instead.
This function returns 0 on success or -1 on error.
(Added in 1.19.44)
guestfs_mke2fs_va
int
guestfs_mke2fs_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_mke2fs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mke2fs_argv
int
guestfs_mke2fs_argv (guestfs_h *g,
const char *device,
const struct guestfs_mke2fs_argv *optargs);
This is the "argv variant" of "guestfs_mke2fs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mke2fs_J
int
guestfs_mke2fs_J (guestfs_h *g,
const char *fstype,
int blocksize,
const char *device,
const char *journal);
This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This creates an ext2/3/4 filesystem on "device" with an external journal on "journal". It is equivalent
to the command:
mke2fs -t fstype -b blocksize -J device=<journal> <device>
See also "guestfs_mke2journal".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2fs_JL
int
guestfs_mke2fs_JL (guestfs_h *g,
const char *fstype,
int blocksize,
const char *device,
const char *label);
This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This creates an ext2/3/4 filesystem on "device" with an external journal on the journal labeled "label".
See also "guestfs_mke2journal_L".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2fs_JU
int
guestfs_mke2fs_JU (guestfs_h *g,
const char *fstype,
int blocksize,
const char *device,
const char *uuid);
This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This creates an ext2/3/4 filesystem on "device" with an external journal on the journal with UUID "uuid".
See also "guestfs_mke2journal_U".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2journal
int
guestfs_mke2journal (guestfs_h *g,
int blocksize,
const char *device);
This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This creates an ext2 external journal on "device". It is equivalent to the command:
mke2fs -O journal_dev -b blocksize device
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2journal_L
int
guestfs_mke2journal_L (guestfs_h *g,
int blocksize,
const char *label,
const char *device);
This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This creates an ext2 external journal on "device" with label "label".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2journal_U
int
guestfs_mke2journal_U (guestfs_h *g,
int blocksize,
const char *uuid,
const char *device);
This function is deprecated. In new code, use the "guestfs_mke2fs" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This creates an ext2 external journal on "device" with UUID "uuid".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mkfifo
int
guestfs_mkfifo (guestfs_h *g,
int mode,
const char *path);
This call creates a FIFO (named pipe) called "path" with mode "mode". It is just a convenient wrapper
around "guestfs_mknod".
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mkfs
int
guestfs_mkfs (guestfs_h *g,
const char *fstype,
const char *device);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_mkfs_opts" with no optional arguments.
(Added in 0.8)
guestfs_mkfs_opts
int
guestfs_mkfs_opts (guestfs_h *g,
const char *fstype,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MKFS_OPTS_BLOCKSIZE, int blocksize,
GUESTFS_MKFS_OPTS_FEATURES, const char *features,
GUESTFS_MKFS_OPTS_INODE, int inode,
GUESTFS_MKFS_OPTS_SECTORSIZE, int sectorsize,
This function creates a filesystem on "device". The filesystem type is "fstype", for example "ext3".
The optional arguments are:
"blocksize"
The filesystem block size. Supported block sizes depend on the filesystem type, but typically they
are 1024, 2048 or 4096 for Linux ext2/3 filesystems.
For VFAT and NTFS the "blocksize" parameter is treated as the requested cluster size.
For UFS block sizes, please see mkfs.ufs(8).
"features"
This passes the -O parameter to the external mkfs program.
For certain filesystem types, this allows extra filesystem features to be selected. See mke2fs(8)
and mkfs.ufs(8) for more details.
You cannot use this optional parameter with the "gfs" or "gfs2" filesystem type.
"inode"
This passes the -I parameter to the external mke2fs(8) program which sets the inode size (only for
ext2/3/4 filesystems at present).
"sectorsize"
This passes the -S parameter to external mkfs.ufs(8) program, which sets sector size for ufs
filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.7.19)
guestfs_mkfs_opts_va
int
guestfs_mkfs_opts_va (guestfs_h *g,
const char *fstype,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_mkfs_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mkfs_opts_argv
int
guestfs_mkfs_opts_argv (guestfs_h *g,
const char *fstype,
const char *device,
const struct guestfs_mkfs_opts_argv *optargs);
This is the "argv variant" of "guestfs_mkfs_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mkfs_b
int
guestfs_mkfs_b (guestfs_h *g,
const char *fstype,
int blocksize,
const char *device);
This function is deprecated. In new code, use the "guestfs_mkfs" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This call is similar to "guestfs_mkfs", but it allows you to control the block size of the resulting
filesystem. Supported block sizes depend on the filesystem type, but typically they are 1024, 2048 or
4096 only.
For VFAT and NTFS the "blocksize" parameter is treated as the requested cluster size.
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mkfs_btrfs
int
guestfs_mkfs_btrfs (guestfs_h *g,
char *const *devices,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MKFS_BTRFS_ALLOCSTART, int64_t allocstart,
GUESTFS_MKFS_BTRFS_BYTECOUNT, int64_t bytecount,
GUESTFS_MKFS_BTRFS_DATATYPE, const char *datatype,
GUESTFS_MKFS_BTRFS_LEAFSIZE, int leafsize,
GUESTFS_MKFS_BTRFS_LABEL, const char *label,
GUESTFS_MKFS_BTRFS_METADATA, const char *metadata,
GUESTFS_MKFS_BTRFS_NODESIZE, int nodesize,
GUESTFS_MKFS_BTRFS_SECTORSIZE, int sectorsize,
Create a btrfs filesystem, allowing all configurables to be set. For more information on the optional
arguments, see mkfs.btrfs(8).
Since btrfs filesystems can span multiple devices, this takes a non-empty list of devices.
To create general filesystems, use "guestfs_mkfs".
This function returns 0 on success or -1 on error.
(Added in 1.17.25)
guestfs_mkfs_btrfs_va
int
guestfs_mkfs_btrfs_va (guestfs_h *g,
char *const *devices,
va_list args);
This is the "va_list variant" of "guestfs_mkfs_btrfs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mkfs_btrfs_argv
int
guestfs_mkfs_btrfs_argv (guestfs_h *g,
char *const *devices,
const struct guestfs_mkfs_btrfs_argv *optargs);
This is the "argv variant" of "guestfs_mkfs_btrfs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mklost_and_found
int
guestfs_mklost_and_found (guestfs_h *g,
const char *mountpoint);
Make the "lost+found" directory, normally in the root directory of an ext2/3/4 filesystem. "mountpoint"
is the directory under which we try to create the "lost+found" directory.
This function returns 0 on success or -1 on error.
(Added in 1.19.56)
guestfs_mkmountpoint
int
guestfs_mkmountpoint (guestfs_h *g,
const char *exemptpath);
"guestfs_mkmountpoint" and "guestfs_rmmountpoint" are specialized calls that can be used to create extra
mountpoints before mounting the first filesystem.
These calls are only necessary in some very limited circumstances, mainly the case where you want to
mount a mix of unrelated and/or read-only filesystems together.
For example, live CDs often contain a "Russian doll" nest of filesystems, an ISO outer layer, with a
squashfs image inside, with an ext2/3 image inside that. You can unpack this as follows in guestfish:
add-ro Fedora-11-i686-Live.iso
run
mkmountpoint /cd
mkmountpoint /sqsh
mkmountpoint /ext3fs
mount /dev/sda /cd
mount-loop /cd/LiveOS/squashfs.img /sqsh
mount-loop /sqsh/LiveOS/ext3fs.img /ext3fs
The inner filesystem is now unpacked under the /ext3fs mountpoint.
"guestfs_mkmountpoint" is not compatible with "guestfs_umount_all". You may get unexpected errors if you
try to mix these calls. It is safest to manually unmount filesystems and remove mountpoints after use.
"guestfs_umount_all" unmounts filesystems by sorting the paths longest first, so for this to work for
manual mountpoints, you must ensure that the innermost mountpoints have the longest pathnames, as in the
example code above.
For more details see https://bugzilla.redhat.com/show_bug.cgi?id=599503
Autosync [see "guestfs_set_autosync", this is set by default on handles] can cause "guestfs_umount_all"
to be called when the handle is closed which can also trigger these issues.
This function returns 0 on success or -1 on error.
(Added in 1.0.62)
guestfs_mknod
int
guestfs_mknod (guestfs_h *g,
int mode,
int devmajor,
int devminor,
const char *path);
This call creates block or character special devices, or named pipes (FIFOs).
The "mode" parameter should be the mode, using the standard constants. "devmajor" and "devminor" are the
device major and minor numbers, only used when creating block and character special devices.
Note that, just like mknod(2), the mode must be bitwise OR'd with S_IFBLK, S_IFCHR, S_IFIFO or S_IFSOCK
(otherwise this call just creates a regular file). These constants are available in the standard Linux
header files, or you can use "guestfs_mknod_b", "guestfs_mknod_c" or "guestfs_mkfifo" which are wrappers
around this command which bitwise OR in the appropriate constant for you.
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mknod_b
int
guestfs_mknod_b (guestfs_h *g,
int mode,
int devmajor,
int devminor,
const char *path);
This call creates a block device node called "path" with mode "mode" and device major/minor "devmajor"
and "devminor". It is just a convenient wrapper around "guestfs_mknod".
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mknod_c
int
guestfs_mknod_c (guestfs_h *g,
int mode,
int devmajor,
int devminor,
const char *path);
This call creates a char device node called "path" with mode "mode" and device major/minor "devmajor" and
"devminor". It is just a convenient wrapper around "guestfs_mknod".
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mkswap
int
guestfs_mkswap (guestfs_h *g,
const char *device);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_mkswap_opts" with no optional arguments.
(Added in 1.0.55)
guestfs_mkswap_opts
int
guestfs_mkswap_opts (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MKSWAP_OPTS_LABEL, const char *label,
GUESTFS_MKSWAP_OPTS_UUID, const char *uuid,
Create a Linux swap partition on "device".
The option arguments "label" and "uuid" allow you to set the label and/or UUID of the new swap partition.
This function returns 0 on success or -1 on error.
(Added in 1.19.34)
guestfs_mkswap_opts_va
int
guestfs_mkswap_opts_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_mkswap_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mkswap_opts_argv
int
guestfs_mkswap_opts_argv (guestfs_h *g,
const char *device,
const struct guestfs_mkswap_opts_argv *optargs);
This is the "argv variant" of "guestfs_mkswap_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mkswap_L
int
guestfs_mkswap_L (guestfs_h *g,
const char *label,
const char *device);
This function is deprecated. In new code, use the "guestfs_mkswap" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
Create a swap partition on "device" with label "label".
Note that you cannot attach a swap label to a block device (eg. "/dev/sda"), just to a partition. This
appears to be a limitation of the kernel or swap tools.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mkswap_U
int
guestfs_mkswap_U (guestfs_h *g,
const char *uuid,
const char *device);
This function is deprecated. In new code, use the "guestfs_mkswap" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
Create a swap partition on "device" with UUID "uuid".
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mkswap_file
int
guestfs_mkswap_file (guestfs_h *g,
const char *path);
Create a swap file.
This command just writes a swap file signature to an existing file. To create the file itself, use
something like "guestfs_fallocate".
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_mktemp
char *
guestfs_mktemp (guestfs_h *g,
const char *tmpl,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MKTEMP_SUFFIX, const char *suffix,
This command creates a temporary file. The "tmpl" parameter should be a full pathname for the temporary
directory name with the final six characters being "XXXXXX".
For example: "/tmp/myprogXXXXXX" or "/Temp/myprogXXXXXX", the second one being suitable for Windows
filesystems.
The name of the temporary file that was created is returned.
The temporary file is created with mode 0600 and is owned by root.
The caller is responsible for deleting the temporary file after use.
If the optional "suffix" parameter is given, then the suffix (eg. ".txt") is appended to the temporary
name.
See also: "guestfs_mkdtemp".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.19.53)
guestfs_mktemp_va
char *
guestfs_mktemp_va (guestfs_h *g,
const char *tmpl,
va_list args);
This is the "va_list variant" of "guestfs_mktemp".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mktemp_argv
char *
guestfs_mktemp_argv (guestfs_h *g,
const char *tmpl,
const struct guestfs_mktemp_argv *optargs);
This is the "argv variant" of "guestfs_mktemp".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_modprobe
int
guestfs_modprobe (guestfs_h *g,
const char *modulename);
This loads a kernel module in the appliance.
The kernel module must have been whitelisted when libguestfs was built (see "appliance/kmod.whitelist.in"
in the source).
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mount
int
guestfs_mount (guestfs_h *g,
const char *mountable,
const char *mountpoint);
Mount a guest disk at a position in the filesystem. Block devices are named "/dev/sda", "/dev/sdb" and
so on, as they were added to the guest. If those block devices contain partitions, they will have the
usual names (eg. "/dev/sda1"). Also LVM "/dev/VG/LV"-style names can be used, or 'mountable' strings
returned by "guestfs_list_filesystems" or "guestfs_inspect_get_mountpoints".
The rules are the same as for mount(2): A filesystem must first be mounted on "/" before others can be
mounted. Other filesystems can only be mounted on directories which already exist.
The mounted filesystem is writable, if we have sufficient permissions on the underlying device.
Before libguestfs 1.13.16, this call implicitly added the options "sync" and "noatime". The "sync"
option greatly slowed writes and caused many problems for users. If your program might need to work with
older versions of libguestfs, use "guestfs_mount_options" instead (using an empty string for the first
parameter if you don't want any options).
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_mount_9p
int
guestfs_mount_9p (guestfs_h *g,
const char *mounttag,
const char *mountpoint,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MOUNT_9P_OPTIONS, const char *options,
Mount the virtio-9p filesystem with the tag "mounttag" on the directory "mountpoint".
If required, "trans=virtio" will be automatically added to the options. Any other options required can
be passed in the optional "options" parameter.
This function returns 0 on success or -1 on error.
(Added in 1.11.12)
guestfs_mount_9p_va
int
guestfs_mount_9p_va (guestfs_h *g,
const char *mounttag,
const char *mountpoint,
va_list args);
This is the "va_list variant" of "guestfs_mount_9p".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mount_9p_argv
int
guestfs_mount_9p_argv (guestfs_h *g,
const char *mounttag,
const char *mountpoint,
const struct guestfs_mount_9p_argv *optargs);
This is the "argv variant" of "guestfs_mount_9p".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mount_local
int
guestfs_mount_local (guestfs_h *g,
const char *localmountpoint,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MOUNT_LOCAL_READONLY, int readonly,
GUESTFS_MOUNT_LOCAL_OPTIONS, const char *options,
GUESTFS_MOUNT_LOCAL_CACHETIMEOUT, int cachetimeout,
GUESTFS_MOUNT_LOCAL_DEBUGCALLS, int debugcalls,
This call exports the libguestfs-accessible filesystem to a local mountpoint (directory) called
"localmountpoint". Ordinary reads and writes to files and directories under "localmountpoint" are
redirected through libguestfs.
If the optional "readonly" flag is set to true, then writes to the filesystem return error "EROFS".
"options" is a comma-separated list of mount options. See guestmount(1) for some useful options.
"cachetimeout" sets the timeout (in seconds) for cached directory entries. The default is 60 seconds.
See guestmount(1) for further information.
If "debugcalls" is set to true, then additional debugging information is generated for every FUSE call.
When "guestfs_mount_local" returns, the filesystem is ready, but is not processing requests (access to it
will block). You have to call "guestfs_mount_local_run" to run the main loop.
See "MOUNT LOCAL" in guestfs(3) for full documentation.
This function returns 0 on success or -1 on error.
(Added in 1.17.22)
guestfs_mount_local_va
int
guestfs_mount_local_va (guestfs_h *g,
const char *localmountpoint,
va_list args);
This is the "va_list variant" of "guestfs_mount_local".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mount_local_argv
int
guestfs_mount_local_argv (guestfs_h *g,
const char *localmountpoint,
const struct guestfs_mount_local_argv *optargs);
This is the "argv variant" of "guestfs_mount_local".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mount_local_run
int
guestfs_mount_local_run (guestfs_h *g);
Run the main loop which translates kernel calls to libguestfs calls.
This should only be called after "guestfs_mount_local" returns successfully. The call will not return
until the filesystem is unmounted.
Note you must not make concurrent libguestfs calls on the same handle from another thread.
You may call this from a different thread than the one which called "guestfs_mount_local", subject to the
usual rules for threads and libguestfs (see "MULTIPLE HANDLES AND MULTIPLE THREADS" in guestfs(3)).
See "MOUNT LOCAL" in guestfs(3) for full documentation.
This function returns 0 on success or -1 on error.
(Added in 1.17.22)
guestfs_mount_loop
int
guestfs_mount_loop (guestfs_h *g,
const char *file,
const char *mountpoint);
This command lets you mount "file" (a filesystem image in a file) on a mount point. It is entirely
equivalent to the command "mount -o loop file mountpoint".
This function returns 0 on success or -1 on error.
(Added in 1.0.54)
guestfs_mount_options
int
guestfs_mount_options (guestfs_h *g,
const char *options,
const char *mountable,
const char *mountpoint);
This is the same as the "guestfs_mount" command, but it allows you to set the mount options as for the
mount(8) -o flag.
If the "options" parameter is an empty string, then no options are passed (all options default to
whatever the filesystem uses).
This function returns 0 on success or -1 on error.
(Added in 1.0.10)
guestfs_mount_ro
int
guestfs_mount_ro (guestfs_h *g,
const char *mountable,
const char *mountpoint);
This is the same as the "guestfs_mount" command, but it mounts the filesystem with the read-only (-o ro)
flag.
This function returns 0 on success or -1 on error.
(Added in 1.0.10)
guestfs_mount_vfs
int
guestfs_mount_vfs (guestfs_h *g,
const char *options,
const char *vfstype,
const char *mountable,
const char *mountpoint);
This is the same as the "guestfs_mount" command, but it allows you to set both the mount options and the
vfstype as for the mount(8) -o and -t flags.
This function returns 0 on success or -1 on error.
(Added in 1.0.10)
guestfs_mountpoints
char **
guestfs_mountpoints (guestfs_h *g);
This call is similar to "guestfs_mounts". That call returns a list of devices. This one returns a hash
table (map) of device name to directory where the device is mounted.
This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of
strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing
NULL entry. The caller must free the strings and the array after use.
(Added in 1.0.62)
guestfs_mounts
char **
guestfs_mounts (guestfs_h *g);
This returns the list of currently mounted filesystems. It returns the list of devices (eg. "/dev/sda1",
"/dev/VG/LV").
Some internal mounts are not shown.
See also: "guestfs_mountpoints"
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.8)
guestfs_mv
int
guestfs_mv (guestfs_h *g,
const char *src,
const char *dest);
This moves a file from "src" to "dest" where "dest" is either a destination filename or destination
directory.
See also: "guestfs_rename".
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_nr_devices
int
guestfs_nr_devices (guestfs_h *g);
This returns the number of whole block devices that were added. This is the same as the number of
devices that would be returned if you called "guestfs_list_devices".
To find out the maximum number of devices that could be added, call "guestfs_max_disks".
On error this function returns -1.
(Added in 1.19.15)
guestfs_ntfs_3g_probe
int
guestfs_ntfs_3g_probe (guestfs_h *g,
int rw,
const char *device);
This command runs the ntfs-3g.probe(8) command which probes an NTFS "device" for mountability. (Not all
NTFS volumes can be mounted read-write, and some cannot be mounted at all).
"rw" is a boolean flag. Set it to true if you want to test if the volume can be mounted read-write. Set
it to false if you want to test if the volume can be mounted read-only.
The return value is an integer which 0 if the operation would succeed, or some non-zero value documented
in the ntfs-3g.probe(8) manual page.
On error this function returns -1.
(Added in 1.0.43)
guestfs_ntfsclone_in
int
guestfs_ntfsclone_in (guestfs_h *g,
const char *backupfile,
const char *device);
Restore the "backupfile" (from a previous call to "guestfs_ntfsclone_out") to "device", overwriting any
existing contents of this device.
This function returns 0 on success or -1 on error.
(Added in 1.17.9)
guestfs_ntfsclone_out
int
guestfs_ntfsclone_out (guestfs_h *g,
const char *device,
const char *backupfile,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_NTFSCLONE_OUT_METADATAONLY, int metadataonly,
GUESTFS_NTFSCLONE_OUT_RESCUE, int rescue,
GUESTFS_NTFSCLONE_OUT_IGNOREFSCHECK, int ignorefscheck,
GUESTFS_NTFSCLONE_OUT_PRESERVETIMESTAMPS, int preservetimestamps,
GUESTFS_NTFSCLONE_OUT_FORCE, int force,
Stream the NTFS filesystem "device" to the local file "backupfile". The format used for the backup file
is a special format used by the ntfsclone(8) tool.
If the optional "metadataonly" flag is true, then only the metadata is saved, losing all the user data
(this is useful for diagnosing some filesystem problems).
The optional "rescue", "ignorefscheck", "preservetimestamps" and "force" flags have precise meanings
detailed in the ntfsclone(8) man page.
Use "guestfs_ntfsclone_in" to restore the file back to a libguestfs device.
This function returns 0 on success or -1 on error.
(Added in 1.17.9)
guestfs_ntfsclone_out_va
int
guestfs_ntfsclone_out_va (guestfs_h *g,
const char *device,
const char *backupfile,
va_list args);
This is the "va_list variant" of "guestfs_ntfsclone_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsclone_out_argv
int
guestfs_ntfsclone_out_argv (guestfs_h *g,
const char *device,
const char *backupfile,
const struct guestfs_ntfsclone_out_argv *optargs);
This is the "argv variant" of "guestfs_ntfsclone_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsfix
int
guestfs_ntfsfix (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_NTFSFIX_CLEARBADSECTORS, int clearbadsectors,
This command repairs some fundamental NTFS inconsistencies, resets the NTFS journal file, and schedules
an NTFS consistency check for the first boot into Windows.
This is not an equivalent of Windows "chkdsk". It does not scan the filesystem for inconsistencies.
The optional "clearbadsectors" flag clears the list of bad sectors. This is useful after cloning a disk
with bad sectors to a new disk.
This function returns 0 on success or -1 on error.
(Added in 1.17.9)
guestfs_ntfsfix_va
int
guestfs_ntfsfix_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_ntfsfix".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsfix_argv
int
guestfs_ntfsfix_argv (guestfs_h *g,
const char *device,
const struct guestfs_ntfsfix_argv *optargs);
This is the "argv variant" of "guestfs_ntfsfix".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsresize
int
guestfs_ntfsresize (guestfs_h *g,
const char *device);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_ntfsresize_opts" with no optional arguments.
(Added in 1.3.2)
guestfs_ntfsresize_opts
int
guestfs_ntfsresize_opts (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_NTFSRESIZE_OPTS_SIZE, int64_t size,
GUESTFS_NTFSRESIZE_OPTS_FORCE, int force,
This command resizes an NTFS filesystem, expanding or shrinking it to the size of the underlying device.
The optional parameters are:
"size"
The new size (in bytes) of the filesystem. If omitted, the filesystem is resized to fit the
container (eg. partition).
"force"
If this option is true, then force the resize of the filesystem even if the filesystem is marked as
requiring a consistency check.
After the resize operation, the filesystem is always marked as requiring a consistency check (for
safety). You have to boot into Windows to perform this check and clear this condition. If you don't
set the "force" option then it is not possible to call "guestfs_ntfsresize" multiple times on a
single filesystem without booting into Windows between each resize.
See also ntfsresize(8).
This function returns 0 on success or -1 on error.
(Added in 1.11.15)
guestfs_ntfsresize_opts_va
int
guestfs_ntfsresize_opts_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_ntfsresize_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsresize_opts_argv
int
guestfs_ntfsresize_opts_argv (guestfs_h *g,
const char *device,
const struct guestfs_ntfsresize_opts_argv *optargs);
This is the "argv variant" of "guestfs_ntfsresize_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsresize_size
int
guestfs_ntfsresize_size (guestfs_h *g,
const char *device,
int64_t size);
This function is deprecated. In new code, use the "guestfs_ntfsresize" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This command is the same as "guestfs_ntfsresize" except that it allows you to specify the new size (in
bytes) explicitly.
This function returns 0 on success or -1 on error.
(Added in 1.3.14)
guestfs_parse_environment
int
guestfs_parse_environment (guestfs_h *g);
Parse the program's environment and set flags in the handle accordingly. For example if
"LIBGUESTFS_DEBUG=1" then the 'verbose' flag is set in the handle.
Most programs do not need to call this. It is done implicitly when you call "guestfs_create".
See "ENVIRONMENT VARIABLES" in guestfs(3) for a list of environment variables that can affect libguestfs
handles. See also "guestfs_create_flags" in guestfs(3), and "guestfs_parse_environment_list".
This function returns 0 on success or -1 on error.
(Added in 1.19.53)
guestfs_parse_environment_list
int
guestfs_parse_environment_list (guestfs_h *g,
char *const *environment);
Parse the list of strings in the argument "environment" and set flags in the handle accordingly. For
example if "LIBGUESTFS_DEBUG=1" is a string in the list, then the 'verbose' flag is set in the handle.
This is the same as "guestfs_parse_environment" except that it parses an explicit list of strings instead
of the program's environment.
This function returns 0 on success or -1 on error.
(Added in 1.19.53)
guestfs_part_add
int
guestfs_part_add (guestfs_h *g,
const char *device,
const char *prlogex,
int64_t startsect,
int64_t endsect);
This command adds a partition to "device". If there is no partition table on the device, call
"guestfs_part_init" first.
The "prlogex" parameter is the type of partition. Normally you should pass "p" or "primary" here, but
MBR partition tables also support "l" (or "logical") and "e" (or "extended") partition types.
"startsect" and "endsect" are the start and end of the partition in sectors. "endsect" may be negative,
which means it counts backwards from the end of the disk ("-1" is the last sector).
Creating a partition which covers the whole disk is not so easy. Use "guestfs_part_disk" to do that.
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_del
int
guestfs_part_del (guestfs_h *g,
const char *device,
int partnum);
This command deletes the partition numbered "partnum" on "device".
Note that in the case of MBR partitioning, deleting an extended partition also deletes any logical
partitions it contains.
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_part_disk
int
guestfs_part_disk (guestfs_h *g,
const char *device,
const char *parttype);
This command is simply a combination of "guestfs_part_init" followed by "guestfs_part_add" to create a
single primary partition covering the whole disk.
"parttype" is the partition table type, usually "mbr" or "gpt", but other possible values are described
in "guestfs_part_init".
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_get_bootable
int
guestfs_part_get_bootable (guestfs_h *g,
const char *device,
int partnum);
This command returns true if the partition "partnum" on "device" has the bootable flag set.
See also "guestfs_part_set_bootable".
This function returns a C truth value on success or -1 on error.
(Added in 1.3.2)
guestfs_part_get_gpt_type
char *
guestfs_part_get_gpt_type (guestfs_h *g,
const char *device,
int partnum);
Return the type GUID of numbered GPT partition "partnum". For MBR partitions, return an appropriate GUID
corresponding to the MBR type. Behaviour is undefined for other partition types.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.21.1)
guestfs_part_get_mbr_id
int
guestfs_part_get_mbr_id (guestfs_h *g,
const char *device,
int partnum);
Returns the MBR type byte (also known as the ID byte) from the numbered partition "partnum".
Note that only MBR (old DOS-style) partitions have type bytes. You will get undefined results for other
partition table types (see "guestfs_part_get_parttype").
On error this function returns -1.
(Added in 1.3.2)
guestfs_part_get_parttype
char *
guestfs_part_get_parttype (guestfs_h *g,
const char *device);
This command examines the partition table on "device" and returns the partition table type (format) being
used.
Common return values include: "msdos" (a DOS/Windows style MBR partition table), "gpt" (a GPT/EFI-style
partition table). Other values are possible, although unusual. See "guestfs_part_init" for a full list.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.78)
guestfs_part_init
int
guestfs_part_init (guestfs_h *g,
const char *device,
const char *parttype);
This creates an empty partition table on "device" of one of the partition types listed below. Usually
"parttype" should be either "msdos" or "gpt" (for large disks).
Initially there are no partitions. Following this, you should call "guestfs_part_add" for each partition
required.
Possible values for "parttype" are:
efi
gpt Intel EFI / GPT partition table.
This is recommended for >= 2 TB partitions that will be accessed from Linux and Intel-based Mac OS X.
It also has limited backwards compatibility with the "mbr" format.
mbr
msdos
The standard PC "Master Boot Record" (MBR) format used by MS-DOS and Windows. This partition type
will only work for device sizes up to 2 TB. For large disks we recommend using "gpt".
Other partition table types that may work but are not supported include:
aix AIX disk labels.
amiga
rdb Amiga "Rigid Disk Block" format.
bsd BSD disk labels.
dasd
DASD, used on IBM mainframes.
dvh MIPS/SGI volumes.
mac Old Mac partition format. Modern Macs use "gpt".
pc98
NEC PC-98 format, common in Japan apparently.
sun Sun disk labels.
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_list
struct guestfs_partition_list *
guestfs_part_list (guestfs_h *g,
const char *device);
This command parses the partition table on "device" and returns the list of partitions found.
The fields in the returned structure are:
part_num
Partition number, counting from 1.
part_start
Start of the partition in bytes. To get sectors you have to divide by the device's sector size, see
"guestfs_blockdev_getss".
part_end
End of the partition in bytes.
part_size
Size of the partition in bytes.
This function returns a "struct guestfs_partition_list *", or NULL if there was an error. The caller
must call "guestfs_free_partition_list" after use.
(Added in 1.0.78)
guestfs_part_set_bootable
int
guestfs_part_set_bootable (guestfs_h *g,
const char *device,
int partnum,
int bootable);
This sets the bootable flag on partition numbered "partnum" on device "device". Note that partitions are
numbered from 1.
The bootable flag is used by some operating systems (notably Windows) to determine which partition to
boot from. It is by no means universally recognized.
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_set_gpt_type
int
guestfs_part_set_gpt_type (guestfs_h *g,
const char *device,
int partnum,
const char *guid);
Set the type GUID of numbered GPT partition "partnum" to "guid". Return an error if the partition table
of "device" isn't GPT, or if "guid" is not a valid GUID.
See http://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs for a useful list of type
GUIDs.
This function returns 0 on success or -1 on error.
(Added in 1.21.1)
guestfs_part_set_mbr_id
int
guestfs_part_set_mbr_id (guestfs_h *g,
const char *device,
int partnum,
int idbyte);
Sets the MBR type byte (also known as the ID byte) of the numbered partition "partnum" to "idbyte". Note
that the type bytes quoted in most documentation are in fact hexadecimal numbers, but usually documented
without any leading "0x" which might be confusing.
Note that only MBR (old DOS-style) partitions have type bytes. You will get undefined results for other
partition table types (see "guestfs_part_get_parttype").
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_part_set_name
int
guestfs_part_set_name (guestfs_h *g,
const char *device,
int partnum,
const char *name);
This sets the partition name on partition numbered "partnum" on device "device". Note that partitions
are numbered from 1.
The partition name can only be set on certain types of partition table. This works on "gpt" but not on
"mbr" partitions.
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_to_dev
char *
guestfs_part_to_dev (guestfs_h *g,
const char *partition);
This function takes a partition name (eg. "/dev/sdb1") and removes the partition number, returning the
device name (eg. "/dev/sdb").
The named partition must exist, for example as a string returned from "guestfs_list_partitions".
See also "guestfs_part_to_partnum", "guestfs_device_index".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.5.15)
guestfs_part_to_partnum
int
guestfs_part_to_partnum (guestfs_h *g,
const char *partition);
This function takes a partition name (eg. "/dev/sdb1") and returns the partition number (eg. 1).
The named partition must exist, for example as a string returned from "guestfs_list_partitions".
See also "guestfs_part_to_dev".
On error this function returns -1.
(Added in 1.13.25)
guestfs_ping_daemon
int
guestfs_ping_daemon (guestfs_h *g);
This is a test probe into the guestfs daemon running inside the hypervisor. Calling this function checks
that the daemon responds to the ping message, without affecting the daemon or attached block device(s) in
any other way.
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_pread
char *
guestfs_pread (guestfs_h *g,
const char *path,
int count,
int64_t offset,
size_t *size_r);
This command lets you read part of a file. It reads "count" bytes of the file, starting at "offset",
from file "path".
This may read fewer bytes than requested. For further details see the pread(2) system call.
See also "guestfs_pwrite", "guestfs_pread_device".
This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r.
The caller must free the returned buffer after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.77)
guestfs_pread_device
char *
guestfs_pread_device (guestfs_h *g,
const char *device,
int count,
int64_t offset,
size_t *size_r);
This command lets you read part of a block device. It reads "count" bytes of "device", starting at
"offset".
This may read fewer bytes than requested. For further details see the pread(2) system call.
See also "guestfs_pread".
This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r.
The caller must free the returned buffer after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.5.21)
guestfs_pvchange_uuid
int
guestfs_pvchange_uuid (guestfs_h *g,
const char *device);
Generate a new random UUID for the physical volume "device".
This function returns 0 on success or -1 on error.
(Added in 1.19.26)
guestfs_pvchange_uuid_all
int
guestfs_pvchange_uuid_all (guestfs_h *g);
Generate new random UUIDs for all physical volumes.
This function returns 0 on success or -1 on error.
(Added in 1.19.26)
guestfs_pvcreate
int
guestfs_pvcreate (guestfs_h *g,
const char *device);
This creates an LVM physical volume on the named "device", where "device" should usually be a partition
name such as "/dev/sda1".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_pvremove
int
guestfs_pvremove (guestfs_h *g,
const char *device);
This wipes a physical volume "device" so that LVM will no longer recognise it.
The implementation uses the "pvremove" command which refuses to wipe physical volumes that contain any
volume groups, so you have to remove those first.
This function returns 0 on success or -1 on error.
(Added in 1.0.13)
guestfs_pvresize
int
guestfs_pvresize (guestfs_h *g,
const char *device);
This resizes (expands or shrinks) an existing LVM physical volume to match the new size of the underlying
device.
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_pvresize_size
int
guestfs_pvresize_size (guestfs_h *g,
const char *device,
int64_t size);
This command is the same as "guestfs_pvresize" except that it allows you to specify the new size (in
bytes) explicitly.
This function returns 0 on success or -1 on error.
(Added in 1.3.14)
guestfs_pvs
char **
guestfs_pvs (guestfs_h *g);
List all the physical volumes detected. This is the equivalent of the pvs(8) command.
This returns a list of just the device names that contain PVs (eg. "/dev/sda2").
See also "guestfs_pvs_full".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.4)
guestfs_pvs_full
struct guestfs_lvm_pv_list *
guestfs_pvs_full (guestfs_h *g);
List all the physical volumes detected. This is the equivalent of the pvs(8) command. The "full"
version includes all fields.
This function returns a "struct guestfs_lvm_pv_list *", or NULL if there was an error. The caller must
call "guestfs_free_lvm_pv_list" after use.
(Added in 0.4)
guestfs_pvuuid
char *
guestfs_pvuuid (guestfs_h *g,
const char *device);
This command returns the UUID of the LVM PV "device".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.87)
guestfs_pwrite
int
guestfs_pwrite (guestfs_h *g,
const char *path,
const char *content,
size_t content_size,
int64_t offset);
This command writes to part of a file. It writes the data buffer "content" to the file "path" starting
at offset "offset".
This command implements the pwrite(2) system call, and like that system call it may not write the full
data requested. The return value is the number of bytes that were actually written to the file. This
could even be 0, although short writes are unlikely for regular files in ordinary circumstances.
See also "guestfs_pread", "guestfs_pwrite_device".
On error this function returns -1.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.3.14)
guestfs_pwrite_device
int
guestfs_pwrite_device (guestfs_h *g,
const char *device,
const char *content,
size_t content_size,
int64_t offset);
This command writes to part of a device. It writes the data buffer "content" to "device" starting at
offset "offset".
This command implements the pwrite(2) system call, and like that system call it may not write the full
data requested (although short writes to disk devices and partitions are probably impossible with
standard Linux kernels).
See also "guestfs_pwrite".
On error this function returns -1.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.5.20)
guestfs_read_file
char *
guestfs_read_file (guestfs_h *g,
const char *path,
size_t *size_r);
This calls returns the contents of the file "path" as a buffer.
Unlike "guestfs_cat", this function can correctly handle files that contain embedded ASCII NUL
characters.
This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r.
The caller must free the returned buffer after use.
(Added in 1.0.63)
guestfs_read_lines
char **
guestfs_read_lines (guestfs_h *g,
const char *path);
Return the contents of the file named "path".
The file contents are returned as a list of lines. Trailing "LF" and "CRLF" character sequences are not
returned.
Note that this function cannot correctly handle binary files (specifically, files containing "\0"
character which is treated as end of string). For those you need to use the "guestfs_read_file" function
and split the buffer into lines yourself.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.7)
guestfs_readdir
struct guestfs_dirent_list *
guestfs_readdir (guestfs_h *g,
const char *dir);
This returns the list of directory entries in directory "dir".
All entries in the directory are returned, including "." and "..". The entries are not sorted, but
returned in the same order as the underlying filesystem.
Also this call returns basic file type information about each file. The "ftyp" field will contain one of
the following characters:
'b' Block special
'c' Char special
'd' Directory
'f' FIFO (named pipe)
'l' Symbolic link
'r' Regular file
's' Socket
'u' Unknown file type
'?' The readdir(3) call returned a "d_type" field with an unexpected value
This function is primarily intended for use by programs. To get a simple list of names, use
"guestfs_ls". To get a printable directory for human consumption, use "guestfs_ll".
This function returns a "struct guestfs_dirent_list *", or NULL if there was an error. The caller must
call "guestfs_free_dirent_list" after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.55)
guestfs_readlink
char *
guestfs_readlink (guestfs_h *g,
const char *path);
This command reads the target of a symbolic link.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.66)
guestfs_readlinklist
char **
guestfs_readlinklist (guestfs_h *g,
const char *path,
char *const *names);
This call allows you to do a "readlink" operation on multiple files, where all files are in the directory
"path". "names" is the list of files from this directory.
On return you get a list of strings, with a one-to-one correspondence to the "names" list. Each string
is the value of the symbolic link.
If the readlink(2) operation fails on any name, then the corresponding result string is the empty string
"". However the whole operation is completed even if there were readlink(2) errors, and so you can call
this function with names where you don't know if they are symbolic links already (albeit slightly less
efficient).
This call is intended for programs that want to efficiently list a directory contents without making many
round-trips.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.0.77)
guestfs_realpath
char *
guestfs_realpath (guestfs_h *g,
const char *path);
Return the canonicalized absolute pathname of "path". The returned path has no ".", ".." or symbolic
link path elements.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.66)
guestfs_remount
int
guestfs_remount (guestfs_h *g,
const char *mountpoint,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_REMOUNT_RW, int rw,
This call allows you to change the "rw" (readonly/read-write) flag on an already mounted filesystem at
"mountpoint", converting a readonly filesystem to be read-write, or vice-versa.
Note that at the moment you must supply the "optional" "rw" parameter. In future we may allow other
flags to be adjusted.
This function returns 0 on success or -1 on error.
(Added in 1.23.2)
guestfs_remount_va
int
guestfs_remount_va (guestfs_h *g,
const char *mountpoint,
va_list args);
This is the "va_list variant" of "guestfs_remount".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_remount_argv
int
guestfs_remount_argv (guestfs_h *g,
const char *mountpoint,
const struct guestfs_remount_argv *optargs);
This is the "argv variant" of "guestfs_remount".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_remove_drive
int
guestfs_remove_drive (guestfs_h *g,
const char *label);
This function is conceptually the opposite of "guestfs_add_drive_opts". It removes the drive that was
previously added with label "label".
Note that in order to remove drives, you have to add them with labels (see the optional "label" argument
to "guestfs_add_drive_opts"). If you didn't use a label, then they cannot be removed.
You can call this function before or after launching the handle. If called after launch, if the backend
supports it, we try to hot unplug the drive: see "HOTPLUGGING" in guestfs(3). The disk must not be in
use (eg. mounted) when you do this. We try to detect if the disk is in use and stop you from doing this.
This function returns 0 on success or -1 on error.
(Added in 1.19.49)
guestfs_removexattr
int
guestfs_removexattr (guestfs_h *g,
const char *xattr,
const char *path);
This call removes the extended attribute named "xattr" of the file "path".
See also: "guestfs_lremovexattr", attr(5).
This function returns 0 on success or -1 on error.
(Added in 1.0.59)
guestfs_rename
int
guestfs_rename (guestfs_h *g,
const char *oldpath,
const char *newpath);
Rename a file to a new place on the same filesystem. This is the same as the Linux rename(2) system
call. In most cases you are better to use "guestfs_mv" instead.
This function returns 0 on success or -1 on error.
(Added in 1.21.5)
guestfs_resize2fs
int
guestfs_resize2fs (guestfs_h *g,
const char *device);
This resizes an ext2, ext3 or ext4 filesystem to match the size of the underlying device.
See also "RESIZE2FS ERRORS" in guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.0.27)
guestfs_resize2fs_M
int
guestfs_resize2fs_M (guestfs_h *g,
const char *device);
This command is the same as "guestfs_resize2fs", but the filesystem is resized to its minimum size. This
works like the -M option to the "resize2fs" command.
To get the resulting size of the filesystem you should call "guestfs_tune2fs_l" and read the "Block size"
and "Block count" values. These two numbers, multiplied together, give the resulting size of the minimal
filesystem in bytes.
See also "RESIZE2FS ERRORS" in guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.9.4)
guestfs_resize2fs_size
int
guestfs_resize2fs_size (guestfs_h *g,
const char *device,
int64_t size);
This command is the same as "guestfs_resize2fs" except that it allows you to specify the new size (in
bytes) explicitly.
See also "RESIZE2FS ERRORS" in guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.3.14)
guestfs_rm
int
guestfs_rm (guestfs_h *g,
const char *path);
Remove the single file "path".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_rm_f
int
guestfs_rm_f (guestfs_h *g,
const char *path);
Remove the file "path".
If the file doesn't exist, that error is ignored. (Other errors, eg. I/O errors or bad paths, are not
ignored)
This call cannot remove directories. Use "guestfs_rmdir" to remove an empty directory, or
"guestfs_rm_rf" to remove directories recursively.
This function returns 0 on success or -1 on error.
(Added in 1.19.42)
guestfs_rm_rf
int
guestfs_rm_rf (guestfs_h *g,
const char *path);
Remove the file or directory "path", recursively removing the contents if its a directory. This is like
the "rm -rf" shell command.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_rmdir
int
guestfs_rmdir (guestfs_h *g,
const char *path);
Remove the single directory "path".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_rmmountpoint
int
guestfs_rmmountpoint (guestfs_h *g,
const char *exemptpath);
This calls removes a mountpoint that was previously created with "guestfs_mkmountpoint". See
"guestfs_mkmountpoint" for full details.
This function returns 0 on success or -1 on error.
(Added in 1.0.62)
guestfs_rsync
int
guestfs_rsync (guestfs_h *g,
const char *src,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_RSYNC_ARCHIVE, int archive,
GUESTFS_RSYNC_DELETEDEST, int deletedest,
This call may be used to copy or synchronize two directories under the same libguestfs handle. This uses
the rsync(1) program which uses a fast algorithm that avoids copying files unnecessarily.
"src" and "dest" are the source and destination directories. Files are copied from "src" to "dest".
The optional arguments are:
"archive"
Turns on archive mode. This is the same as passing the --archive flag to "rsync".
"deletedest"
Delete files at the destination that do not exist at the source.
This function returns 0 on success or -1 on error.
(Added in 1.19.29)
guestfs_rsync_va
int
guestfs_rsync_va (guestfs_h *g,
const char *src,
const char *dest,
va_list args);
This is the "va_list variant" of "guestfs_rsync".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_rsync_argv
int
guestfs_rsync_argv (guestfs_h *g,
const char *src,
const char *dest,
const struct guestfs_rsync_argv *optargs);
This is the "argv variant" of "guestfs_rsync".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_rsync_in
int
guestfs_rsync_in (guestfs_h *g,
const char *remote,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_RSYNC_IN_ARCHIVE, int archive,
GUESTFS_RSYNC_IN_DELETEDEST, int deletedest,
This call may be used to copy or synchronize the filesystem on the host or on a remote computer with the
filesystem within libguestfs. This uses the rsync(1) program which uses a fast algorithm that avoids
copying files unnecessarily.
This call only works if the network is enabled. See "guestfs_set_network" or the --network option to
various tools like guestfish(1).
Files are copied from the remote server and directory specified by "remote" to the destination directory
"dest".
The format of the remote server string is defined by rsync(1). Note that there is no way to supply a
password or passphrase so the target must be set up not to require one.
The optional arguments are the same as those of "guestfs_rsync".
This function returns 0 on success or -1 on error.
(Added in 1.19.29)
guestfs_rsync_in_va
int
guestfs_rsync_in_va (guestfs_h *g,
const char *remote,
const char *dest,
va_list args);
This is the "va_list variant" of "guestfs_rsync_in".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_rsync_in_argv
int
guestfs_rsync_in_argv (guestfs_h *g,
const char *remote,
const char *dest,
const struct guestfs_rsync_in_argv *optargs);
This is the "argv variant" of "guestfs_rsync_in".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_rsync_out
int
guestfs_rsync_out (guestfs_h *g,
const char *src,
const char *remote,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_RSYNC_OUT_ARCHIVE, int archive,
GUESTFS_RSYNC_OUT_DELETEDEST, int deletedest,
This call may be used to copy or synchronize the filesystem within libguestfs with a filesystem on the
host or on a remote computer. This uses the rsync(1) program which uses a fast algorithm that avoids
copying files unnecessarily.
This call only works if the network is enabled. See "guestfs_set_network" or the --network option to
various tools like guestfish(1).
Files are copied from the source directory "src" to the remote server and directory specified by
"remote".
The format of the remote server string is defined by rsync(1). Note that there is no way to supply a
password or passphrase so the target must be set up not to require one.
The optional arguments are the same as those of "guestfs_rsync".
Globbing does not happen on the "src" parameter. In programs which use the API directly you have to
expand wildcards yourself (see "guestfs_glob_expand"). In guestfish you can use the "glob" command (see
"glob" in guestfish(1)), for example:
><fs> glob rsync-out /* rsync://remote/
This function returns 0 on success or -1 on error.
(Added in 1.19.29)
guestfs_rsync_out_va
int
guestfs_rsync_out_va (guestfs_h *g,
const char *src,
const char *remote,
va_list args);
This is the "va_list variant" of "guestfs_rsync_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_rsync_out_argv
int
guestfs_rsync_out_argv (guestfs_h *g,
const char *src,
const char *remote,
const struct guestfs_rsync_out_argv *optargs);
This is the "argv variant" of "guestfs_rsync_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_scrub_device
int
guestfs_scrub_device (guestfs_h *g,
const char *device);
This command writes patterns over "device" to make data retrieval more difficult.
It is an interface to the scrub(1) program. See that manual page for more details.
This function returns 0 on success or -1 on error.
(Added in 1.0.52)
guestfs_scrub_file
int
guestfs_scrub_file (guestfs_h *g,
const char *file);
This command writes patterns over a file to make data retrieval more difficult.
The file is removed after scrubbing.
It is an interface to the scrub(1) program. See that manual page for more details.
This function returns 0 on success or -1 on error.
(Added in 1.0.52)
guestfs_scrub_freespace
int
guestfs_scrub_freespace (guestfs_h *g,
const char *dir);
This command creates the directory "dir" and then fills it with files until the filesystem is full, and
scrubs the files as for "guestfs_scrub_file", and deletes them. The intention is to scrub any free space
on the partition containing "dir".
It is an interface to the scrub(1) program. See that manual page for more details.
This function returns 0 on success or -1 on error.
(Added in 1.0.52)
guestfs_set_append
int
guestfs_set_append (guestfs_h *g,
const char *append);
This function is used to add additional options to the guest kernel command line.
The default is "NULL" unless overridden by setting "LIBGUESTFS_APPEND" environment variable.
Setting "append" to "NULL" means no additional options are passed (libguestfs always adds a few of its
own).
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_set_attach_method
int
guestfs_set_attach_method (guestfs_h *g,
const char *backend);
This function is deprecated. In new code, use the "guestfs_set_backend" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
Set the method that libguestfs uses to connect to the backend guestfsd daemon.
See "BACKEND" in guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.9.8)
guestfs_set_autosync
int
guestfs_set_autosync (guestfs_h *g,
int autosync);
If "autosync" is true, this enables autosync. Libguestfs will make a best effort attempt to make
filesystems consistent and synchronized when the handle is closed (also if the program exits without
closing handles).
This is enabled by default (since libguestfs 1.5.24, previously it was disabled by default).
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_set_backend
int
guestfs_set_backend (guestfs_h *g,
const char *backend);
Set the method that libguestfs uses to connect to the backend guestfsd daemon.
This handle property was previously called the "attach method".
See "BACKEND" in guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.21.26)
guestfs_set_cachedir
int
guestfs_set_cachedir (guestfs_h *g,
const char *cachedir);
Set the directory used by the handle to store the appliance cache, when using a supermin appliance. The
appliance is cached and shared between all handles which have the same effective user ID.
The environment variables "LIBGUESTFS_CACHEDIR" and "TMPDIR" control the default value: If
"LIBGUESTFS_CACHEDIR" is set, then that is the default. Else if "TMPDIR" is set, then that is the
default. Else "/var/tmp" is the default.
This function returns 0 on success or -1 on error.
(Added in 1.19.58)
guestfs_set_direct
int
guestfs_set_direct (guestfs_h *g,
int direct);
If the direct appliance mode flag is enabled, then stdin and stdout are passed directly through to the
appliance once it is launched.
One consequence of this is that log messages aren't caught by the library and handled by
"guestfs_set_log_message_callback", but go straight to stdout.
You probably don't want to use this unless you know what you are doing.
The default is disabled.
This function returns 0 on success or -1 on error.
(Added in 1.0.72)
guestfs_set_e2attrs
int
guestfs_set_e2attrs (guestfs_h *g,
const char *file,
const char *attrs,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_SET_E2ATTRS_CLEAR, int clear,
This sets or clears the file attributes "attrs" associated with the inode "file".
"attrs" is a string of characters representing file attributes. See "guestfs_get_e2attrs" for a list of
possible attributes. Not all attributes can be changed.
If optional boolean "clear" is not present or false, then the "attrs" listed are set in the inode.
If "clear" is true, then the "attrs" listed are cleared in the inode.
In both cases, other attributes not present in the "attrs" string are left unchanged.
These attributes are only present when the file is located on an ext2/3/4 filesystem. Using this call on
other filesystem types will result in an error.
This function returns 0 on success or -1 on error.
(Added in 1.17.31)
guestfs_set_e2attrs_va
int
guestfs_set_e2attrs_va (guestfs_h *g,
const char *file,
const char *attrs,
va_list args);
This is the "va_list variant" of "guestfs_set_e2attrs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_set_e2attrs_argv
int
guestfs_set_e2attrs_argv (guestfs_h *g,
const char *file,
const char *attrs,
const struct guestfs_set_e2attrs_argv *optargs);
This is the "argv variant" of "guestfs_set_e2attrs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_set_e2generation
int
guestfs_set_e2generation (guestfs_h *g,
const char *file,
int64_t generation);
This sets the ext2 file generation of a file.
See "guestfs_get_e2generation".
This function returns 0 on success or -1 on error.
(Added in 1.17.31)
guestfs_set_e2label
int
guestfs_set_e2label (guestfs_h *g,
const char *device,
const char *label);
This function is deprecated. In new code, use the "guestfs_set_label" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This sets the ext2/3/4 filesystem label of the filesystem on "device" to "label". Filesystem labels are
limited to 16 characters.
You can use either "guestfs_tune2fs_l" or "guestfs_get_e2label" to return the existing label on a
filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.0.15)
guestfs_set_e2uuid
int
guestfs_set_e2uuid (guestfs_h *g,
const char *device,
const char *uuid);
This function is deprecated. In new code, use the "guestfs_set_uuid" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This sets the ext2/3/4 filesystem UUID of the filesystem on "device" to "uuid". The format of the UUID
and alternatives such as "clear", "random" and "time" are described in the tune2fs(8) manpage.
You can use "guestfs_vfs_uuid" to return the existing UUID of a filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.0.15)
guestfs_set_hv
int
guestfs_set_hv (guestfs_h *g,
const char *hv);
Set the hypervisor binary that we will use. The hypervisor depends on the backend, but is usually the
location of the qemu/KVM hypervisor. For the uml backend, it is the location of the "linux" or "vmlinux"
binary.
The default is chosen when the library was compiled by the configure script.
You can also override this by setting the "LIBGUESTFS_HV" environment variable.
Note that you should call this function as early as possible after creating the handle. This is because
some pre-launch operations depend on testing qemu features (by running "qemu -help"). If the qemu binary
changes, we don't retest features, and so you might see inconsistent results. Using the environment
variable "LIBGUESTFS_HV" is safest of all since that picks the qemu binary at the same time as the handle
is created.
This function returns 0 on success or -1 on error.
(Added in 1.23.17)
guestfs_set_label
int
guestfs_set_label (guestfs_h *g,
const char *mountable,
const char *label);
Set the filesystem label on "mountable" to "label".
Only some filesystem types support labels, and libguestfs supports setting labels on only a subset of
these.
ext2, ext3, ext4
Labels are limited to 16 bytes.
NTFS
Labels are limited to 128 unicode characters.
XFS The label is limited to 12 bytes. The filesystem must not be mounted when trying to set the label.
btrfs
The label is limited to 256 bytes and some characters are not allowed. Setting the label on a btrfs
subvolume will set the label on its parent filesystem. The filesystem must not be mounted when
trying to set the label.
To read the label on a filesystem, call "guestfs_vfs_label".
This function returns 0 on success or -1 on error.
(Added in 1.17.9)
guestfs_set_libvirt_requested_credential
int
guestfs_set_libvirt_requested_credential (guestfs_h *g,
int index,
const char *cred,
size_t cred_size);
After requesting the "index"'th credential from the user, call this function to pass the answer back to
libvirt.
See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.
This function returns 0 on success or -1 on error.
(Added in 1.19.52)
guestfs_set_libvirt_supported_credentials
int
guestfs_set_libvirt_supported_credentials (guestfs_h *g,
char *const *creds);
Call this function before setting an event handler for "GUESTFS_EVENT_LIBVIRT_AUTH", to supply the list
of credential types that the program knows how to process.
The "creds" list must be a non-empty list of strings. Possible strings are:
"username"
"authname"
"language"
"cnonce"
"passphrase"
"echoprompt"
"noechoprompt"
"realm"
"external"
See libvirt documentation for the meaning of these credential types.
See "LIBVIRT AUTHENTICATION" in guestfs(3) for documentation and example code.
This function returns 0 on success or -1 on error.
(Added in 1.19.52)
guestfs_set_memsize
int
guestfs_set_memsize (guestfs_h *g,
int memsize);
This sets the memory size in megabytes allocated to the hypervisor. This only has any effect if called
before "guestfs_launch".
You can also change this by setting the environment variable "LIBGUESTFS_MEMSIZE" before the handle is
created.
For more information on the architecture of libguestfs, see guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_set_network
int
guestfs_set_network (guestfs_h *g,
int network);
If "network" is true, then the network is enabled in the libguestfs appliance. The default is false.
This affects whether commands are able to access the network (see "RUNNING COMMANDS" in guestfs(3)).
You must call this before calling "guestfs_launch", otherwise it has no effect.
This function returns 0 on success or -1 on error.
(Added in 1.5.4)
guestfs_set_path
int
guestfs_set_path (guestfs_h *g,
const char *searchpath);
Set the path that libguestfs searches for kernel and initrd.img.
The default is "$libdir/guestfs" unless overridden by setting "LIBGUESTFS_PATH" environment variable.
Setting "path" to "NULL" restores the default path.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_set_pgroup
int
guestfs_set_pgroup (guestfs_h *g,
int pgroup);
If "pgroup" is true, child processes are placed into their own process group.
The practical upshot of this is that signals like "SIGINT" (from users pressing "^C") won't be received
by the child process.
The default for this flag is false, because usually you want "^C" to kill the subprocess. Guestfish sets
this flag to true when used interactively, so that "^C" can cancel long-running commands gracefully (see
"guestfs_user_cancel").
This function returns 0 on success or -1 on error.
(Added in 1.11.18)
guestfs_set_program
int
guestfs_set_program (guestfs_h *g,
const char *program);
Set the program name. This is an informative string which the main program may optionally set in the
handle.
When the handle is created, the program name in the handle is set to the basename from "argv[0]". If
that was not possible, it is set to the empty string (but never "NULL").
This function returns 0 on success or -1 on error.
(Added in 1.21.29)
guestfs_set_qemu
int
guestfs_set_qemu (guestfs_h *g,
const char *hv);
This function is deprecated. In new code, use the "guestfs_set_hv" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
Set the hypervisor binary (usually qemu) that we will use.
The default is chosen when the library was compiled by the configure script.
You can also override this by setting the "LIBGUESTFS_HV" environment variable.
Setting "hv" to "NULL" restores the default qemu binary.
Note that you should call this function as early as possible after creating the handle. This is because
some pre-launch operations depend on testing qemu features (by running "qemu -help"). If the qemu binary
changes, we don't retest features, and so you might see inconsistent results. Using the environment
variable "LIBGUESTFS_HV" is safest of all since that picks the qemu binary at the same time as the handle
is created.
This function returns 0 on success or -1 on error.
(Added in 1.0.6)
guestfs_set_recovery_proc
int
guestfs_set_recovery_proc (guestfs_h *g,
int recoveryproc);
If this is called with the parameter "false" then "guestfs_launch" does not create a recovery process.
The purpose of the recovery process is to stop runaway hypervisor processes in the case where the main
program aborts abruptly.
This only has any effect if called before "guestfs_launch", and the default is true.
About the only time when you would want to disable this is if the main process will fork itself into the
background ("daemonize" itself). In this case the recovery process thinks that the main program has
disappeared and so kills the hypervisor, which is not very helpful.
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_set_selinux
int
guestfs_set_selinux (guestfs_h *g,
int selinux);
This sets the selinux flag that is passed to the appliance at boot time. The default is "selinux=0"
(disabled).
Note that if SELinux is enabled, it is always in Permissive mode ("enforcing=0").
For more information on the architecture of libguestfs, see guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.0.67)
guestfs_set_smp
int
guestfs_set_smp (guestfs_h *g,
int smp);
Change the number of virtual CPUs assigned to the appliance. The default is 1. Increasing this may
improve performance, though often it has no effect.
This function must be called before "guestfs_launch".
This function returns 0 on success or -1 on error.
(Added in 1.13.15)
guestfs_set_tmpdir
int
guestfs_set_tmpdir (guestfs_h *g,
const char *tmpdir);
Set the directory used by the handle to store temporary files.
The environment variables "LIBGUESTFS_TMPDIR" and "TMPDIR" control the default value: If
"LIBGUESTFS_TMPDIR" is set, then that is the default. Else if "TMPDIR" is set, then that is the default.
Else "/tmp" is the default.
This function returns 0 on success or -1 on error.
(Added in 1.19.58)
guestfs_set_trace
int
guestfs_set_trace (guestfs_h *g,
int trace);
If the command trace flag is set to 1, then libguestfs calls, parameters and return values are traced.
If you want to trace C API calls into libguestfs (and other libraries) then possibly a better way is to
use the external ltrace(1) command.
Command traces are disabled unless the environment variable "LIBGUESTFS_TRACE" is defined and set to 1.
Trace messages are normally sent to "stderr", unless you register a callback to send them somewhere else
(see "guestfs_set_event_callback").
This function returns 0 on success or -1 on error.
(Added in 1.0.69)
guestfs_set_uuid
int
guestfs_set_uuid (guestfs_h *g,
const char *device,
const char *uuid);
Set the filesystem UIUD on "device" to "label".
Only some filesystem types support setting UUIDs.
To read the UUID on a filesystem, call "guestfs_vfs_uuid".
This function returns 0 on success or -1 on error.
(Added in 1.23.10)
guestfs_set_verbose
int
guestfs_set_verbose (guestfs_h *g,
int verbose);
If "verbose" is true, this turns on verbose messages.
Verbose messages are disabled unless the environment variable "LIBGUESTFS_DEBUG" is defined and set to 1.
Verbose messages are normally sent to "stderr", unless you register a callback to send them somewhere
else (see "guestfs_set_event_callback").
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_setcon
int
guestfs_setcon (guestfs_h *g,
const char *context);
This sets the SELinux security context of the daemon to the string "context".
See the documentation about SELINUX in guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.0.67)
guestfs_setxattr
int
guestfs_setxattr (guestfs_h *g,
const char *xattr,
const char *val,
int vallen,
const char *path);
This call sets the extended attribute named "xattr" of the file "path" to the value "val" (of length
"vallen"). The value is arbitrary 8 bit data.
See also: "guestfs_lsetxattr", attr(5).
This function returns 0 on success or -1 on error.
(Added in 1.0.59)
guestfs_sfdisk
int
guestfs_sfdisk (guestfs_h *g,
const char *device,
int cyls,
int heads,
int sectors,
char *const *lines);
This function is deprecated. In new code, use the "guestfs_part_add" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This is a direct interface to the sfdisk(8) program for creating partitions on block devices.
"device" should be a block device, for example "/dev/sda".
"cyls", "heads" and "sectors" are the number of cylinders, heads and sectors on the device, which are
passed directly to sfdisk as the -C, -H and -S parameters. If you pass 0 for any of these, then the
corresponding parameter is omitted. Usually for 'large' disks, you can just pass 0 for these, but for
small (floppy-sized) disks, sfdisk (or rather, the kernel) cannot work out the right geometry and you
will need to tell it.
"lines" is a list of lines that we feed to "sfdisk". For more information refer to the sfdisk(8)
manpage.
To create a single partition occupying the whole disk, you would pass "lines" as a single element list,
when the single element being the string "," (comma).
See also: "guestfs_sfdisk_l", "guestfs_sfdisk_N", "guestfs_part_init"
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_sfdiskM
int
guestfs_sfdiskM (guestfs_h *g,
const char *device,
char *const *lines);
This function is deprecated. In new code, use the "guestfs_part_add" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This is a simplified interface to the "guestfs_sfdisk" command, where partition sizes are specified in
megabytes only (rounded to the nearest cylinder) and you don't need to specify the cyls, heads and
sectors parameters which were rarely if ever used anyway.
See also: "guestfs_sfdisk", the sfdisk(8) manpage and "guestfs_part_disk"
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_sfdisk_N
int
guestfs_sfdisk_N (guestfs_h *g,
const char *device,
int partnum,
int cyls,
int heads,
int sectors,
const char *line);
This function is deprecated. In new code, use the "guestfs_part_add" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This runs sfdisk(8) option to modify just the single partition "n" (note: "n" counts from 1).
For other parameters, see "guestfs_sfdisk". You should usually pass 0 for the cyls/heads/sectors
parameters.
See also: "guestfs_part_add"
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_sfdisk_disk_geometry
char *
guestfs_sfdisk_disk_geometry (guestfs_h *g,
const char *device);
This displays the disk geometry of "device" read from the partition table. Especially in the case where
the underlying block device has been resized, this can be different from the kernel's idea of the
geometry (see "guestfs_sfdisk_kernel_geometry").
The result is in human-readable format, and not designed to be parsed.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.26)
guestfs_sfdisk_kernel_geometry
char *
guestfs_sfdisk_kernel_geometry (guestfs_h *g,
const char *device);
This displays the kernel's idea of the geometry of "device".
The result is in human-readable format, and not designed to be parsed.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.26)
guestfs_sfdisk_l
char *
guestfs_sfdisk_l (guestfs_h *g,
const char *device);
This function is deprecated. In new code, use the "guestfs_part_list" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This displays the partition table on "device", in the human-readable output of the sfdisk(8) command. It
is not intended to be parsed.
See also: "guestfs_part_list"
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.26)
guestfs_sh
char *
guestfs_sh (guestfs_h *g,
const char *command);
This call runs a command from the guest filesystem via the guest's "/bin/sh".
This is like "guestfs_command", but passes the command to:
/bin/sh -c "command"
Depending on the guest's shell, this usually results in wildcards being expanded, shell expressions being
interpolated and so on.
All the provisos about "guestfs_command" apply to this call.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.50)
guestfs_sh_lines
char **
guestfs_sh_lines (guestfs_h *g,
const char *command);
This is the same as "guestfs_sh", but splits the result into a list of lines.
See also: "guestfs_command_lines"
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.0.50)
guestfs_shutdown
int
guestfs_shutdown (guestfs_h *g);
This is the opposite of "guestfs_launch". It performs an orderly shutdown of the backend process(es).
If the autosync flag is set (which is the default) then the disk image is synchronized.
If the subprocess exits with an error then this function will return an error, which should not be
ignored (it may indicate that the disk image could not be written out properly).
It is safe to call this multiple times. Extra calls are ignored.
This call does not close or free up the handle. You still need to call "guestfs_close" afterwards.
"guestfs_close" will call this if you don't do it explicitly, but note that any errors are ignored in
that case.
This function returns 0 on success or -1 on error.
(Added in 1.19.16)
guestfs_sleep
int
guestfs_sleep (guestfs_h *g,
int secs);
Sleep for "secs" seconds.
This function returns 0 on success or -1 on error.
(Added in 1.0.41)
guestfs_stat
struct guestfs_stat *
guestfs_stat (guestfs_h *g,
const char *path);
Returns file information for the given "path".
This is the same as the stat(2) system call.
This function returns a "struct guestfs_stat *", or NULL if there was an error. The caller must call
"guestfs_free_stat" after use.
(Added in 0.9.2)
guestfs_statvfs
struct guestfs_statvfs *
guestfs_statvfs (guestfs_h *g,
const char *path);
Returns file system statistics for any mounted file system. "path" should be a file or directory in the
mounted file system (typically it is the mount point itself, but it doesn't need to be).
This is the same as the statvfs(2) system call.
This function returns a "struct guestfs_statvfs *", or NULL if there was an error. The caller must call
"guestfs_free_statvfs" after use.
(Added in 0.9.2)
guestfs_strings
char **
guestfs_strings (guestfs_h *g,
const char *path);
This runs the strings(1) command on a file and returns the list of printable strings found.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.22)
guestfs_strings_e
char **
guestfs_strings_e (guestfs_h *g,
const char *encoding,
const char *path);
This is like the "guestfs_strings" command, but allows you to specify the encoding of strings that are
looked for in the source file "path".
Allowed encodings are:
s Single 7-bit-byte characters like ASCII and the ASCII-compatible parts of ISO-8859-X (this is what
"guestfs_strings" uses).
S Single 8-bit-byte characters.
b 16-bit big endian strings such as those encoded in UTF-16BE or UCS-2BE.
l (lower case letter L)
16-bit little endian such as UTF-16LE and UCS-2LE. This is useful for examining binaries in Windows
guests.
B 32-bit big endian such as UCS-4BE.
L 32-bit little endian such as UCS-4LE.
The returned strings are transcoded to UTF-8.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.22)
guestfs_swapoff_device
int
guestfs_swapoff_device (guestfs_h *g,
const char *device);
This command disables the libguestfs appliance swap device or partition named "device". See
"guestfs_swapon_device".
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapoff_file
int
guestfs_swapoff_file (guestfs_h *g,
const char *file);
This command disables the libguestfs appliance swap on file.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapoff_label
int
guestfs_swapoff_label (guestfs_h *g,
const char *label);
This command disables the libguestfs appliance swap on labeled swap partition.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapoff_uuid
int
guestfs_swapoff_uuid (guestfs_h *g,
const char *uuid);
This command disables the libguestfs appliance swap partition with the given UUID.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapon_device
int
guestfs_swapon_device (guestfs_h *g,
const char *device);
This command enables the libguestfs appliance to use the swap device or partition named "device". The
increased memory is made available for all commands, for example those run using "guestfs_command" or
"guestfs_sh".
Note that you should not swap to existing guest swap partitions unless you know what you are doing. They
may contain hibernation information, or other information that the guest doesn't want you to trash. You
also risk leaking information about the host to the guest this way. Instead, attach a new host device to
the guest and swap on that.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapon_file
int
guestfs_swapon_file (guestfs_h *g,
const char *file);
This command enables swap to a file. See "guestfs_swapon_device" for other notes.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapon_label
int
guestfs_swapon_label (guestfs_h *g,
const char *label);
This command enables swap to a labeled swap partition. See "guestfs_swapon_device" for other notes.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapon_uuid
int
guestfs_swapon_uuid (guestfs_h *g,
const char *uuid);
This command enables swap to a swap partition with the given UUID. See "guestfs_swapon_device" for other
notes.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_sync
int
guestfs_sync (guestfs_h *g);
This syncs the disk, so that any writes are flushed through to the underlying disk image.
You should always call this if you have modified a disk image, before closing the handle.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_syslinux
int
guestfs_syslinux (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_SYSLINUX_DIRECTORY, const char *directory,
Install the SYSLINUX bootloader on "device".
The device parameter must be either a whole disk formatted as a FAT filesystem, or a partition formatted
as a FAT filesystem. In the latter case, the partition should be marked as "active"
("guestfs_part_set_bootable") and a Master Boot Record must be installed (eg. using
"guestfs_pwrite_device") on the first sector of the whole disk. The SYSLINUX package comes with some
suitable Master Boot Records. See the syslinux(1) man page for further information.
The optional arguments are:
"directory"
Install SYSLINUX in the named subdirectory, instead of in the root directory of the FAT filesystem.
Additional configuration can be supplied to SYSLINUX by placing a file called "syslinux.cfg" on the FAT
filesystem, either in the root directory, or under "directory" if that optional argument is being used.
For further information about the contents of this file, see syslinux(1).
See also "guestfs_extlinux".
This function returns 0 on success or -1 on error.
(Added in 1.21.27)
guestfs_syslinux_va
int
guestfs_syslinux_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_syslinux".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_syslinux_argv
int
guestfs_syslinux_argv (guestfs_h *g,
const char *device,
const struct guestfs_syslinux_argv *optargs);
This is the "argv variant" of "guestfs_syslinux".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_tail
char **
guestfs_tail (guestfs_h *g,
const char *path);
This command returns up to the last 10 lines of a file as a list of strings.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.54)
guestfs_tail_n
char **
guestfs_tail_n (guestfs_h *g,
int nrlines,
const char *path);
If the parameter "nrlines" is a positive number, this returns the last "nrlines" lines of the file
"path".
If the parameter "nrlines" is a negative number, this returns lines from the file "path", starting with
the "-nrlines"th line.
If the parameter "nrlines" is zero, this returns an empty list.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.54)
guestfs_tar_in
int
guestfs_tar_in (guestfs_h *g,
const char *tarfile,
const char *directory);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_tar_in_opts" with no optional arguments.
(Added in 1.0.3)
guestfs_tar_in_opts
int
guestfs_tar_in_opts (guestfs_h *g,
const char *tarfile,
const char *directory,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_TAR_IN_OPTS_COMPRESS, const char *compress,
This command uploads and unpacks local file "tarfile" into "directory".
The optional "compress" flag controls compression. If not given, then the input should be an
uncompressed tar file. Otherwise one of the following strings may be given to select the compression
type of the input file: "compress", "gzip", "bzip2", "xz", "lzop". (Note that not all builds of
libguestfs will support all of these compression types).
This function returns 0 on success or -1 on error.
(Added in 1.19.30)
guestfs_tar_in_opts_va
int
guestfs_tar_in_opts_va (guestfs_h *g,
const char *tarfile,
const char *directory,
va_list args);
This is the "va_list variant" of "guestfs_tar_in_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_tar_in_opts_argv
int
guestfs_tar_in_opts_argv (guestfs_h *g,
const char *tarfile,
const char *directory,
const struct guestfs_tar_in_opts_argv *optargs);
This is the "argv variant" of "guestfs_tar_in_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_tar_out
int
guestfs_tar_out (guestfs_h *g,
const char *directory,
const char *tarfile);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_tar_out_opts" with no optional arguments.
(Added in 1.0.3)
guestfs_tar_out_opts
int
guestfs_tar_out_opts (guestfs_h *g,
const char *directory,
const char *tarfile,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_TAR_OUT_OPTS_COMPRESS, const char *compress,
GUESTFS_TAR_OUT_OPTS_NUMERICOWNER, int numericowner,
GUESTFS_TAR_OUT_OPTS_EXCLUDES, char *const *excludes,
This command packs the contents of "directory" and downloads it to local file "tarfile".
The optional "compress" flag controls compression. If not given, then the output will be an uncompressed
tar file. Otherwise one of the following strings may be given to select the compression type of the
output file: "compress", "gzip", "bzip2", "xz", "lzop". (Note that not all builds of libguestfs will
support all of these compression types).
The other optional arguments are:
"excludes"
A list of wildcards. Files are excluded if they match any of the wildcards.
"numericowner"
If set to true, the output tar file will contain UID/GID numbers instead of user/group names.
This function returns 0 on success or -1 on error.
(Added in 1.19.30)
guestfs_tar_out_opts_va
int
guestfs_tar_out_opts_va (guestfs_h *g,
const char *directory,
const char *tarfile,
va_list args);
This is the "va_list variant" of "guestfs_tar_out_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_tar_out_opts_argv
int
guestfs_tar_out_opts_argv (guestfs_h *g,
const char *directory,
const char *tarfile,
const struct guestfs_tar_out_opts_argv *optargs);
This is the "argv variant" of "guestfs_tar_out_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_tgz_in
int
guestfs_tgz_in (guestfs_h *g,
const char *tarball,
const char *directory);
This function is deprecated. In new code, use the "guestfs_tar_in" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This command uploads and unpacks local file "tarball" (a gzip compressed tar file) into "directory".
This function returns 0 on success or -1 on error.
(Added in 1.0.3)
guestfs_tgz_out
int
guestfs_tgz_out (guestfs_h *g,
const char *directory,
const char *tarball);
This function is deprecated. In new code, use the "guestfs_tar_out" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This command packs the contents of "directory" and downloads it to local file "tarball".
This function returns 0 on success or -1 on error.
(Added in 1.0.3)
guestfs_touch
int
guestfs_touch (guestfs_h *g,
const char *path);
Touch acts like the touch(1) command. It can be used to update the timestamps on a file, or, if the file
does not exist, to create a new zero-length file.
This command only works on regular files, and will fail on other file types such as directories, symbolic
links, block special etc.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_truncate
int
guestfs_truncate (guestfs_h *g,
const char *path);
This command truncates "path" to a zero-length file. The file must exist already.
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_truncate_size
int
guestfs_truncate_size (guestfs_h *g,
const char *path,
int64_t size);
This command truncates "path" to size "size" bytes. The file must exist already.
If the current file size is less than "size" then the file is extended to the required size with zero
bytes. This creates a sparse file (ie. disk blocks are not allocated for the file until you write to
it). To create a non-sparse file of zeroes, use "guestfs_fallocate64" instead.
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_tune2fs
int
guestfs_tune2fs (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_TUNE2FS_FORCE, int force,
GUESTFS_TUNE2FS_MAXMOUNTCOUNT, int maxmountcount,
GUESTFS_TUNE2FS_MOUNTCOUNT, int mountcount,
GUESTFS_TUNE2FS_ERRORBEHAVIOR, const char *errorbehavior,
GUESTFS_TUNE2FS_GROUP, int64_t group,
GUESTFS_TUNE2FS_INTERVALBETWEENCHECKS, int intervalbetweenchecks,
GUESTFS_TUNE2FS_RESERVEDBLOCKSPERCENTAGE, int reservedblockspercentage,
GUESTFS_TUNE2FS_LASTMOUNTEDDIRECTORY, const char *lastmounteddirectory,
GUESTFS_TUNE2FS_RESERVEDBLOCKSCOUNT, int64_t reservedblockscount,
GUESTFS_TUNE2FS_USER, int64_t user,
This call allows you to adjust various filesystem parameters of an ext2/ext3/ext4 filesystem called
"device".
The optional parameters are:
"force"
Force tune2fs to complete the operation even in the face of errors. This is the same as the tune2fs
"-f" option.
"maxmountcount"
Set the number of mounts after which the filesystem is checked by e2fsck(8). If this is 0 then the
number of mounts is disregarded. This is the same as the tune2fs "-c" option.
"mountcount"
Set the number of times the filesystem has been mounted. This is the same as the tune2fs "-C"
option.
"errorbehavior"
Change the behavior of the kernel code when errors are detected. Possible values currently are:
"continue", "remount-ro", "panic". In practice these options don't really make any difference,
particularly for write errors.
This is the same as the tune2fs "-e" option.
"group"
Set the group which can use reserved filesystem blocks. This is the same as the tune2fs "-g" option
except that it can only be specified as a number.
"intervalbetweenchecks"
Adjust the maximal time between two filesystem checks (in seconds). If the option is passed as 0
then time-dependent checking is disabled.
This is the same as the tune2fs "-i" option.
"reservedblockspercentage"
Set the percentage of the filesystem which may only be allocated by privileged processes. This is
the same as the tune2fs "-m" option.
"lastmounteddirectory"
Set the last mounted directory. This is the same as the tune2fs "-M" option.
"reservedblockscount" Set the number of reserved filesystem blocks. This is the same as the tune2fs "-r"
option.
"user"
Set the user who can use the reserved filesystem blocks. This is the same as the tune2fs "-u" option
except that it can only be specified as a number.
To get the current values of filesystem parameters, see "guestfs_tune2fs_l". For precise details of how
tune2fs works, see the tune2fs(8) man page.
This function returns 0 on success or -1 on error.
(Added in 1.15.4)
guestfs_tune2fs_va
int
guestfs_tune2fs_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_tune2fs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_tune2fs_argv
int
guestfs_tune2fs_argv (guestfs_h *g,
const char *device,
const struct guestfs_tune2fs_argv *optargs);
This is the "argv variant" of "guestfs_tune2fs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_tune2fs_l
char **
guestfs_tune2fs_l (guestfs_h *g,
const char *device);
This returns the contents of the ext2, ext3 or ext4 filesystem superblock on "device".
It is the same as running "tune2fs -l device". See tune2fs(8) manpage for more details. The list of
fields returned isn't clearly defined, and depends on both the version of "tune2fs" that libguestfs was
built against, and the filesystem itself.
This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of
strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing
NULL entry. The caller must free the strings and the array after use.
(Added in 0.9.2)
guestfs_txz_in
int
guestfs_txz_in (guestfs_h *g,
const char *tarball,
const char *directory);
This function is deprecated. In new code, use the "guestfs_tar_in" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This command uploads and unpacks local file "tarball" (an xz compressed tar file) into "directory".
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_txz_out
int
guestfs_txz_out (guestfs_h *g,
const char *directory,
const char *tarball);
This function is deprecated. In new code, use the "guestfs_tar_out" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This command packs the contents of "directory" and downloads it to local file "tarball" (as an xz
compressed tar archive).
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_umask
int
guestfs_umask (guestfs_h *g,
int mask);
This function sets the mask used for creating new files and device nodes to "mask & 0777".
Typical umask values would be 022 which creates new files with permissions like "-rw-r--r--" or
"-rwxr-xr-x", and 002 which creates new files with permissions like "-rw-rw-r--" or "-rwxrwxr-x".
The default umask is 022. This is important because it means that directories and device nodes will be
created with 0644 or 0755 mode even if you specify 0777.
See also "guestfs_get_umask", umask(2), "guestfs_mknod", "guestfs_mkdir".
This call returns the previous umask.
On error this function returns -1.
(Added in 1.0.55)
guestfs_umount
int
guestfs_umount (guestfs_h *g,
const char *pathordevice);
This function is provided for backwards compatibility with earlier versions of libguestfs. It simply
calls "guestfs_umount_opts" with no optional arguments.
(Added in 0.8)
guestfs_umount_opts
int
guestfs_umount_opts (guestfs_h *g,
const char *pathordevice,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_UMOUNT_OPTS_FORCE, int force,
GUESTFS_UMOUNT_OPTS_LAZYUNMOUNT, int lazyunmount,
This unmounts the given filesystem. The filesystem may be specified either by its mountpoint (path) or
the device which contains the filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.19.25)
guestfs_umount_opts_va
int
guestfs_umount_opts_va (guestfs_h *g,
const char *pathordevice,
va_list args);
This is the "va_list variant" of "guestfs_umount_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_umount_opts_argv
int
guestfs_umount_opts_argv (guestfs_h *g,
const char *pathordevice,
const struct guestfs_umount_opts_argv *optargs);
This is the "argv variant" of "guestfs_umount_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_umount_all
int
guestfs_umount_all (guestfs_h *g);
This unmounts all mounted filesystems.
Some internal mounts are not unmounted by this call.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_umount_local
int
guestfs_umount_local (guestfs_h *g,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_UMOUNT_LOCAL_RETRY, int retry,
If libguestfs is exporting the filesystem on a local mountpoint, then this unmounts it.
See "MOUNT LOCAL" in guestfs(3) for full documentation.
This function returns 0 on success or -1 on error.
(Added in 1.17.22)
guestfs_umount_local_va
int
guestfs_umount_local_va (guestfs_h *g,
va_list args);
This is the "va_list variant" of "guestfs_umount_local".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_umount_local_argv
int
guestfs_umount_local_argv (guestfs_h *g,
const struct guestfs_umount_local_argv *optargs);
This is the "argv variant" of "guestfs_umount_local".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_upload
int
guestfs_upload (guestfs_h *g,
const char *filename,
const char *remotefilename);
Upload local file "filename" to "remotefilename" on the filesystem.
"filename" can also be a named pipe.
See also "guestfs_download".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.0.2)
guestfs_upload_offset
int
guestfs_upload_offset (guestfs_h *g,
const char *filename,
const char *remotefilename,
int64_t offset);
Upload local file "filename" to "remotefilename" on the filesystem.
"remotefilename" is overwritten starting at the byte "offset" specified. The intention is to overwrite
parts of existing files or devices, although if a non-existant file is specified then it is created with
a "hole" before "offset". The size of the data written is implicit in the size of the source "filename".
Note that there is no limit on the amount of data that can be uploaded with this call, unlike with
"guestfs_pwrite", and this call always writes the full amount unless an error occurs.
See also "guestfs_upload", "guestfs_pwrite".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.5.17)
guestfs_user_cancel
int
guestfs_user_cancel (guestfs_h *g);
This function cancels the current upload or download operation.
Unlike most other libguestfs calls, this function is signal safe and thread safe. You can call it from a
signal handler or from another thread, without needing to do any locking.
The transfer that was in progress (if there is one) will stop shortly afterwards, and will return an
error. The errno (see "guestfs_last_errno") is set to "EINTR", so you can test for this to find out if
the operation was cancelled or failed because of another error.
No cleanup is performed: for example, if a file was being uploaded then after cancellation there may be a
partially uploaded file. It is the caller's responsibility to clean up if necessary.
There are two common places that you might call "guestfs_user_cancel":
In an interactive text-based program, you might call it from a "SIGINT" signal handler so that pressing
"^C" cancels the current operation. (You also need to call "guestfs_set_pgroup" so that child processes
don't receive the "^C" signal).
In a graphical program, when the main thread is displaying a progress bar with a cancel button, wire up
the cancel button to call this function.
This function returns 0 on success or -1 on error.
(Added in 1.11.18)
guestfs_utimens
int
guestfs_utimens (guestfs_h *g,
const char *path,
int64_t atsecs,
int64_t atnsecs,
int64_t mtsecs,
int64_t mtnsecs);
This command sets the timestamps of a file with nanosecond precision.
"atsecs, atnsecs" are the last access time (atime) in secs and nanoseconds from the epoch.
"mtsecs, mtnsecs" are the last modification time (mtime) in secs and nanoseconds from the epoch.
If the *nsecs field contains the special value "-1" then the corresponding timestamp is set to the
current time. (The *secs field is ignored in this case).
If the *nsecs field contains the special value "-2" then the corresponding timestamp is left unchanged.
(The *secs field is ignored in this case).
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_utsname
struct guestfs_utsname *
guestfs_utsname (guestfs_h *g);
This returns the kernel version of the appliance, where this is available. This information is only
useful for debugging. Nothing in the returned structure is defined by the API.
This function returns a "struct guestfs_utsname *", or NULL if there was an error. The caller must call
"guestfs_free_utsname" after use.
(Added in 1.19.27)
guestfs_version
struct guestfs_version *
guestfs_version (guestfs_h *g);
Return the libguestfs version number that the program is linked against.
Note that because of dynamic linking this is not necessarily the version of libguestfs that you compiled
against. You can compile the program, and then at runtime dynamically link against a completely
different "libguestfs.so" library.
This call was added in version 1.0.58. In previous versions of libguestfs there was no way to get the
version number. From C code you can use dynamic linker functions to find out if this symbol exists (if
it doesn't, then it's an earlier version).
The call returns a structure with four elements. The first three ("major", "minor" and "release") are
numbers and correspond to the usual version triplet. The fourth element ("extra") is a string and is
normally empty, but may be used for distro-specific information.
To construct the original version string: "$major.$minor.$release$extra"
See also: "LIBGUESTFS VERSION NUMBERS" in guestfs(3).
Note: Don't use this call to test for availability of features. In enterprise distributions we backport
features from later versions into earlier versions, making this an unreliable way to test for features.
Use "guestfs_available" or "guestfs_feature_available" instead.
This function returns a "struct guestfs_version *", or NULL if there was an error. The caller must call
"guestfs_free_version" after use.
(Added in 1.0.58)
guestfs_vfs_label
char *
guestfs_vfs_label (guestfs_h *g,
const char *mountable);
This returns the label of the filesystem on "mountable".
If the filesystem is unlabeled, this returns the empty string.
To find a filesystem from the label, use "guestfs_findfs_label".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.3.18)
guestfs_vfs_type
char *
guestfs_vfs_type (guestfs_h *g,
const char *mountable);
This command gets the filesystem type corresponding to the filesystem on "mountable".
For most filesystems, the result is the name of the Linux VFS module which would be used to mount this
filesystem if you mounted it without specifying the filesystem type. For example a string such as "ext3"
or "ntfs".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.75)
guestfs_vfs_uuid
char *
guestfs_vfs_uuid (guestfs_h *g,
const char *mountable);
This returns the filesystem UUID of the filesystem on "mountable".
If the filesystem does not have a UUID, this returns the empty string.
To find a filesystem from the UUID, use "guestfs_findfs_uuid".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.3.18)
guestfs_vg_activate
int
guestfs_vg_activate (guestfs_h *g,
int activate,
char *const *volgroups);
This command activates or (if "activate" is false) deactivates all logical volumes in the listed volume
groups "volgroups".
This command is the same as running "vgchange -a y|n volgroups..."
Note that if "volgroups" is an empty list then all volume groups are activated or deactivated.
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_vg_activate_all
int
guestfs_vg_activate_all (guestfs_h *g,
int activate);
This command activates or (if "activate" is false) deactivates all logical volumes in all volume groups.
This command is the same as running "vgchange -a y|n"
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_vgchange_uuid
int
guestfs_vgchange_uuid (guestfs_h *g,
const char *vg);
Generate a new random UUID for the volume group "vg".
This function returns 0 on success or -1 on error.
(Added in 1.19.26)
guestfs_vgchange_uuid_all
int
guestfs_vgchange_uuid_all (guestfs_h *g);
Generate new random UUIDs for all volume groups.
This function returns 0 on success or -1 on error.
(Added in 1.19.26)
guestfs_vgcreate
int
guestfs_vgcreate (guestfs_h *g,
const char *volgroup,
char *const *physvols);
This creates an LVM volume group called "volgroup" from the non-empty list of physical volumes
"physvols".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_vglvuuids
char **
guestfs_vglvuuids (guestfs_h *g,
const char *vgname);
Given a VG called "vgname", this returns the UUIDs of all the logical volumes created in this volume
group.
You can use this along with "guestfs_lvs" and "guestfs_lvuuid" calls to associate logical volumes and
volume groups.
See also "guestfs_vgpvuuids".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.0.87)
guestfs_vgmeta
char *
guestfs_vgmeta (guestfs_h *g,
const char *vgname,
size_t *size_r);
"vgname" is an LVM volume group. This command examines the volume group and returns its metadata.
Note that the metadata is an internal structure used by LVM, subject to change at any time, and is
provided for information only.
This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r.
The caller must free the returned buffer after use.
(Added in 1.17.20)
guestfs_vgpvuuids
char **
guestfs_vgpvuuids (guestfs_h *g,
const char *vgname);
Given a VG called "vgname", this returns the UUIDs of all the physical volumes that this volume group
resides on.
You can use this along with "guestfs_pvs" and "guestfs_pvuuid" calls to associate physical volumes and
volume groups.
See also "guestfs_vglvuuids".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 1.0.87)
guestfs_vgremove
int
guestfs_vgremove (guestfs_h *g,
const char *vgname);
Remove an LVM volume group "vgname", (for example "VG").
This also forcibly removes all logical volumes in the volume group (if any).
This function returns 0 on success or -1 on error.
(Added in 1.0.13)
guestfs_vgrename
int
guestfs_vgrename (guestfs_h *g,
const char *volgroup,
const char *newvolgroup);
Rename a volume group "volgroup" with the new name "newvolgroup".
This function returns 0 on success or -1 on error.
(Added in 1.0.83)
guestfs_vgs
char **
guestfs_vgs (guestfs_h *g);
List all the volumes groups detected. This is the equivalent of the vgs(8) command.
This returns a list of just the volume group names that were detected (eg. "VolGroup00").
See also "guestfs_vgs_full".
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
(Added in 0.4)
guestfs_vgs_full
struct guestfs_lvm_vg_list *
guestfs_vgs_full (guestfs_h *g);
List all the volumes groups detected. This is the equivalent of the vgs(8) command. The "full" version
includes all fields.
This function returns a "struct guestfs_lvm_vg_list *", or NULL if there was an error. The caller must
call "guestfs_free_lvm_vg_list" after use.
(Added in 0.4)
guestfs_vgscan
int
guestfs_vgscan (guestfs_h *g);
This rescans all block devices and rebuilds the list of LVM physical volumes, volume groups and logical
volumes.
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_vguuid
char *
guestfs_vguuid (guestfs_h *g,
const char *vgname);
This command returns the UUID of the LVM VG named "vgname".
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.87)
guestfs_wait_ready
int
guestfs_wait_ready (guestfs_h *g);
This function is deprecated. In new code, use the "guestfs_launch" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This function is a no op.
In versions of the API < 1.0.71 you had to call this function just after calling "guestfs_launch" to wait
for the launch to complete. However this is no longer necessary because "guestfs_launch" now does the
waiting.
If you see any calls to this function in code then you can just remove them, unless you want to retain
compatibility with older versions of the API.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_wc_c
int
guestfs_wc_c (guestfs_h *g,
const char *path);
This command counts the characters in a file, using the "wc -c" external command.
On error this function returns -1.
(Added in 1.0.54)
guestfs_wc_l
int
guestfs_wc_l (guestfs_h *g,
const char *path);
This command counts the lines in a file, using the "wc -l" external command.
On error this function returns -1.
(Added in 1.0.54)
guestfs_wc_w
int
guestfs_wc_w (guestfs_h *g,
const char *path);
This command counts the words in a file, using the "wc -w" external command.
On error this function returns -1.
(Added in 1.0.54)
guestfs_wipefs
int
guestfs_wipefs (guestfs_h *g,
const char *device);
This command erases filesystem or RAID signatures from the specified "device" to make the filesystem
invisible to libblkid.
This does not erase the filesystem itself nor any other data from the "device".
Compare with "guestfs_zero" which zeroes the first few blocks of a device.
This function returns 0 on success or -1 on error.
(Added in 1.17.6)
guestfs_write
int
guestfs_write (guestfs_h *g,
const char *path,
const char *content,
size_t content_size);
This call creates a file called "path". The content of the file is the string "content" (which can
contain any 8 bit data).
See also "guestfs_write_append".
This function returns 0 on success or -1 on error.
(Added in 1.3.14)
guestfs_write_append
int
guestfs_write_append (guestfs_h *g,
const char *path,
const char *content,
size_t content_size);
This call appends "content" to the end of file "path". If "path" does not exist, then a new file is
created.
See also "guestfs_write".
This function returns 0 on success or -1 on error.
(Added in 1.11.18)
guestfs_write_file
int
guestfs_write_file (guestfs_h *g,
const char *path,
const char *content,
int size);
This function is deprecated. In new code, use the "guestfs_write" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This call creates a file called "path". The contents of the file is the string "content" (which can
contain any 8 bit data), with length "size".
As a special case, if "size" is 0 then the length is calculated using "strlen" (so in this case the
content cannot contain embedded ASCII NULs).
NB. Owing to a bug, writing content containing ASCII NUL characters does not work, even if the length is
specified.
This function returns 0 on success or -1 on error.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 0.8)
guestfs_xfs_admin
int
guestfs_xfs_admin (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_XFS_ADMIN_EXTUNWRITTEN, int extunwritten,
GUESTFS_XFS_ADMIN_IMGFILE, int imgfile,
GUESTFS_XFS_ADMIN_V2LOG, int v2log,
GUESTFS_XFS_ADMIN_PROJID32BIT, int projid32bit,
GUESTFS_XFS_ADMIN_LAZYCOUNTER, int lazycounter,
GUESTFS_XFS_ADMIN_LABEL, const char *label,
GUESTFS_XFS_ADMIN_UUID, const char *uuid,
Change the parameters of the XFS filesystem on "device".
Devices that are mounted cannot be modified. Administrators must unmount filesystems before this call
can modify parameters.
Some of the parameters of a mounted filesystem can be examined and modified using the "guestfs_xfs_info"
and "guestfs_xfs_growfs" calls.
This function returns 0 on success or -1 on error.
(Added in 1.19.33)
guestfs_xfs_admin_va
int
guestfs_xfs_admin_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_xfs_admin".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_xfs_admin_argv
int
guestfs_xfs_admin_argv (guestfs_h *g,
const char *device,
const struct guestfs_xfs_admin_argv *optargs);
This is the "argv variant" of "guestfs_xfs_admin".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_xfs_growfs
int
guestfs_xfs_growfs (guestfs_h *g,
const char *path,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_XFS_GROWFS_DATASEC, int datasec,
GUESTFS_XFS_GROWFS_LOGSEC, int logsec,
GUESTFS_XFS_GROWFS_RTSEC, int rtsec,
GUESTFS_XFS_GROWFS_DATASIZE, int64_t datasize,
GUESTFS_XFS_GROWFS_LOGSIZE, int64_t logsize,
GUESTFS_XFS_GROWFS_RTSIZE, int64_t rtsize,
GUESTFS_XFS_GROWFS_RTEXTSIZE, int64_t rtextsize,
GUESTFS_XFS_GROWFS_MAXPCT, int maxpct,
Grow the XFS filesystem mounted at "path".
The returned struct contains geometry information. Missing fields are returned as "-1" (for numeric
fields) or empty string.
This function returns 0 on success or -1 on error.
(Added in 1.19.28)
guestfs_xfs_growfs_va
int
guestfs_xfs_growfs_va (guestfs_h *g,
const char *path,
va_list args);
This is the "va_list variant" of "guestfs_xfs_growfs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_xfs_growfs_argv
int
guestfs_xfs_growfs_argv (guestfs_h *g,
const char *path,
const struct guestfs_xfs_growfs_argv *optargs);
This is the "argv variant" of "guestfs_xfs_growfs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_xfs_info
struct guestfs_xfsinfo *
guestfs_xfs_info (guestfs_h *g,
const char *pathordevice);
"pathordevice" is a mounted XFS filesystem or a device containing an XFS filesystem. This command
returns the geometry of the filesystem.
The returned struct contains geometry information. Missing fields are returned as "-1" (for numeric
fields) or empty string.
This function returns a "struct guestfs_xfsinfo *", or NULL if there was an error. The caller must call
"guestfs_free_xfsinfo" after use.
(Added in 1.19.21)
guestfs_xfs_repair
int
guestfs_xfs_repair (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of the following pairs of
parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_XFS_REPAIR_FORCELOGZERO, int forcelogzero,
GUESTFS_XFS_REPAIR_NOMODIFY, int nomodify,
GUESTFS_XFS_REPAIR_NOPREFETCH, int noprefetch,
GUESTFS_XFS_REPAIR_FORCEGEOMETRY, int forcegeometry,
GUESTFS_XFS_REPAIR_MAXMEM, int64_t maxmem,
GUESTFS_XFS_REPAIR_IHASHSIZE, int64_t ihashsize,
GUESTFS_XFS_REPAIR_BHASHSIZE, int64_t bhashsize,
GUESTFS_XFS_REPAIR_AGSTRIDE, int64_t agstride,
GUESTFS_XFS_REPAIR_LOGDEV, const char *logdev,
GUESTFS_XFS_REPAIR_RTDEV, const char *rtdev,
Repair corrupt or damaged XFS filesystem on "device".
The filesystem is specified using the "device" argument which should be the device name of the disk
partition or volume containing the filesystem. If given the name of a block device, "xfs_repair" will
attempt to find the raw device associated with the specified block device and will use the raw device
instead.
Regardless, the filesystem to be repaired must be unmounted, otherwise, the resulting filesystem may be
inconsistent or corrupt.
The returned status indicates whether filesystem corruption was detected (returns 1) or was not detected
(returns 0).
On error this function returns -1.
(Added in 1.19.36)
guestfs_xfs_repair_va
int
guestfs_xfs_repair_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_xfs_repair".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_xfs_repair_argv
int
guestfs_xfs_repair_argv (guestfs_h *g,
const char *device,
const struct guestfs_xfs_repair_argv *optargs);
This is the "argv variant" of "guestfs_xfs_repair".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_zegrep
char **
guestfs_zegrep (guestfs_h *g,
const char *regex,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "zegrep" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_zegrepi
char **
guestfs_zegrepi (guestfs_h *g,
const char *regex,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "zegrep -i" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_zero
int
guestfs_zero (guestfs_h *g,
const char *device);
This command writes zeroes over the first few blocks of "device".
How many blocks are zeroed isn't specified (but it's not enough to securely wipe the device). It should
be sufficient to remove any partition tables, filesystem superblocks and so on.
If blocks are already zero, then this command avoids writing zeroes. This prevents the underlying device
from becoming non-sparse or growing unnecessarily.
See also: "guestfs_zero_device", "guestfs_scrub_device", "guestfs_is_zero_device"
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.0.16)
guestfs_zero_device
int
guestfs_zero_device (guestfs_h *g,
const char *device);
This command writes zeroes over the entire "device". Compare with "guestfs_zero" which just zeroes the
first few blocks of a device.
If blocks are already zero, then this command avoids writing zeroes. This prevents the underlying device
from becoming non-sparse or growing unnecessarily.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.3.1)
guestfs_zero_free_space
int
guestfs_zero_free_space (guestfs_h *g,
const char *directory);
Zero the free space in the filesystem mounted on "directory". The filesystem must be mounted read-write.
The filesystem contents are not affected, but any free space in the filesystem is freed.
Free space is not "trimmed". You may want to call "guestfs_fstrim" either as an alternative to this, or
after calling this, depending on your requirements.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that the caller can display a
progress bar or indicator. To receive these messages, the caller must register a progress event
callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3).
(Added in 1.17.18)
guestfs_zerofree
int
guestfs_zerofree (guestfs_h *g,
const char *device);
This runs the zerofree program on "device". This program claims to zero unused inodes and disk blocks on
an ext2/3 filesystem, thus making it possible to compress the filesystem more effectively.
You should not run this program if the filesystem is mounted.
It is possible that using this program can damage the filesystem or data on the filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_zfgrep
char **
guestfs_zfgrep (guestfs_h *g,
const char *pattern,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "zfgrep" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_zfgrepi
char **
guestfs_zfgrepi (guestfs_h *g,
const char *pattern,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "zfgrep -i" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_zfile
char *
guestfs_zfile (guestfs_h *g,
const char *meth,
const char *path);
This function is deprecated. In new code, use the "guestfs_file" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This command runs "file" after first decompressing "path" using "method".
"method" must be one of "gzip", "compress" or "bzip2".
Since 1.0.63, use "guestfs_file" instead which can now process compressed files.
This function returns a string, or NULL on error. The caller must free the returned string after use.
(Added in 1.0.59)
guestfs_zgrep
char **
guestfs_zgrep (guestfs_h *g,
const char *regex,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "zgrep" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
guestfs_zgrepi
char **
guestfs_zgrepi (guestfs_h *g,
const char *regex,
const char *path);
This function is deprecated. In new code, use the "guestfs_grep" call instead.
Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates
that there are problems with correct use of these functions.
This calls the external "zgrep -i" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an
error. The caller must free the strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See
"PROTOCOL LIMITS" in guestfs(3).
(Added in 1.0.66)
STRUCTURES
guestfs_int_bool
struct guestfs_int_bool {
int32_t i;
int32_t b;
};
struct guestfs_int_bool_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_int_bool *val; /* Elements. */
};
void guestfs_free_int_bool (struct guestfs_int_bool *);
void guestfs_free_int_bool_list (struct guestfs_int_bool_list *);
guestfs_lvm_pv
struct guestfs_lvm_pv {
char *pv_name;
/* The next field is NOT nul-terminated, be careful when printing it: */
char pv_uuid[32];
char *pv_fmt;
uint64_t pv_size;
uint64_t dev_size;
uint64_t pv_free;
uint64_t pv_used;
char *pv_attr;
int64_t pv_pe_count;
int64_t pv_pe_alloc_count;
char *pv_tags;
uint64_t pe_start;
int64_t pv_mda_count;
uint64_t pv_mda_free;
};
struct guestfs_lvm_pv_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_lvm_pv *val; /* Elements. */
};
void guestfs_free_lvm_pv (struct guestfs_lvm_pv *);
void guestfs_free_lvm_pv_list (struct guestfs_lvm_pv_list *);
guestfs_lvm_vg
struct guestfs_lvm_vg {
char *vg_name;
/* The next field is NOT nul-terminated, be careful when printing it: */
char vg_uuid[32];
char *vg_fmt;
char *vg_attr;
uint64_t vg_size;
uint64_t vg_free;
char *vg_sysid;
uint64_t vg_extent_size;
int64_t vg_extent_count;
int64_t vg_free_count;
int64_t max_lv;
int64_t max_pv;
int64_t pv_count;
int64_t lv_count;
int64_t snap_count;
int64_t vg_seqno;
char *vg_tags;
int64_t vg_mda_count;
uint64_t vg_mda_free;
};
struct guestfs_lvm_vg_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_lvm_vg *val; /* Elements. */
};
void guestfs_free_lvm_vg (struct guestfs_lvm_vg *);
void guestfs_free_lvm_vg_list (struct guestfs_lvm_vg_list *);
guestfs_lvm_lv
struct guestfs_lvm_lv {
char *lv_name;
/* The next field is NOT nul-terminated, be careful when printing it: */
char lv_uuid[32];
char *lv_attr;
int64_t lv_major;
int64_t lv_minor;
int64_t lv_kernel_major;
int64_t lv_kernel_minor;
uint64_t lv_size;
int64_t seg_count;
char *origin;
/* The next field is [0..100] or -1 meaning 'not present': */
float snap_percent;
/* The next field is [0..100] or -1 meaning 'not present': */
float copy_percent;
char *move_pv;
char *lv_tags;
char *mirror_log;
char *modules;
};
struct guestfs_lvm_lv_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_lvm_lv *val; /* Elements. */
};
void guestfs_free_lvm_lv (struct guestfs_lvm_lv *);
void guestfs_free_lvm_lv_list (struct guestfs_lvm_lv_list *);
guestfs_stat
struct guestfs_stat {
int64_t dev;
int64_t ino;
int64_t mode;
int64_t nlink;
int64_t uid;
int64_t gid;
int64_t rdev;
int64_t size;
int64_t blksize;
int64_t blocks;
int64_t atime;
int64_t mtime;
int64_t ctime;
};
struct guestfs_stat_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_stat *val; /* Elements. */
};
void guestfs_free_stat (struct guestfs_stat *);
void guestfs_free_stat_list (struct guestfs_stat_list *);
guestfs_statvfs
struct guestfs_statvfs {
int64_t bsize;
int64_t frsize;
int64_t blocks;
int64_t bfree;
int64_t bavail;
int64_t files;
int64_t ffree;
int64_t favail;
int64_t fsid;
int64_t flag;
int64_t namemax;
};
struct guestfs_statvfs_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_statvfs *val; /* Elements. */
};
void guestfs_free_statvfs (struct guestfs_statvfs *);
void guestfs_free_statvfs_list (struct guestfs_statvfs_list *);
guestfs_dirent
struct guestfs_dirent {
int64_t ino;
char ftyp;
char *name;
};
struct guestfs_dirent_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_dirent *val; /* Elements. */
};
void guestfs_free_dirent (struct guestfs_dirent *);
void guestfs_free_dirent_list (struct guestfs_dirent_list *);
guestfs_version
struct guestfs_version {
int64_t major;
int64_t minor;
int64_t release;
char *extra;
};
struct guestfs_version_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_version *val; /* Elements. */
};
void guestfs_free_version (struct guestfs_version *);
void guestfs_free_version_list (struct guestfs_version_list *);
guestfs_xattr
struct guestfs_xattr {
char *attrname;
/* The next two fields describe a byte array. */
uint32_t attrval_len;
char *attrval;
};
struct guestfs_xattr_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_xattr *val; /* Elements. */
};
void guestfs_free_xattr (struct guestfs_xattr *);
void guestfs_free_xattr_list (struct guestfs_xattr_list *);
guestfs_inotify_event
struct guestfs_inotify_event {
int64_t in_wd;
uint32_t in_mask;
uint32_t in_cookie;
char *in_name;
};
struct guestfs_inotify_event_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_inotify_event *val; /* Elements. */
};
void guestfs_free_inotify_event (struct guestfs_inotify_event *);
void guestfs_free_inotify_event_list (struct guestfs_inotify_event_list *);
guestfs_partition
struct guestfs_partition {
int32_t part_num;
uint64_t part_start;
uint64_t part_end;
uint64_t part_size;
};
struct guestfs_partition_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_partition *val; /* Elements. */
};
void guestfs_free_partition (struct guestfs_partition *);
void guestfs_free_partition_list (struct guestfs_partition_list *);
guestfs_application
struct guestfs_application {
char *app_name;
char *app_display_name;
int32_t app_epoch;
char *app_version;
char *app_release;
char *app_install_path;
char *app_trans_path;
char *app_publisher;
char *app_url;
char *app_source_package;
char *app_summary;
char *app_description;
};
struct guestfs_application_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_application *val; /* Elements. */
};
void guestfs_free_application (struct guestfs_application *);
void guestfs_free_application_list (struct guestfs_application_list *);
guestfs_application2
struct guestfs_application2 {
char *app2_name;
char *app2_display_name;
int32_t app2_epoch;
char *app2_version;
char *app2_release;
char *app2_arch;
char *app2_install_path;
char *app2_trans_path;
char *app2_publisher;
char *app2_url;
char *app2_source_package;
char *app2_summary;
char *app2_description;
char *app2_spare1;
char *app2_spare2;
char *app2_spare3;
char *app2_spare4;
};
struct guestfs_application2_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_application2 *val; /* Elements. */
};
void guestfs_free_application2 (struct guestfs_application2 *);
void guestfs_free_application2_list (struct guestfs_application2_list *);
guestfs_isoinfo
struct guestfs_isoinfo {
char *iso_system_id;
char *iso_volume_id;
uint32_t iso_volume_space_size;
uint32_t iso_volume_set_size;
uint32_t iso_volume_sequence_number;
uint32_t iso_logical_block_size;
char *iso_volume_set_id;
char *iso_publisher_id;
char *iso_data_preparer_id;
char *iso_application_id;
char *iso_copyright_file_id;
char *iso_abstract_file_id;
char *iso_bibliographic_file_id;
int64_t iso_volume_creation_t;
int64_t iso_volume_modification_t;
int64_t iso_volume_expiration_t;
int64_t iso_volume_effective_t;
};
struct guestfs_isoinfo_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_isoinfo *val; /* Elements. */
};
void guestfs_free_isoinfo (struct guestfs_isoinfo *);
void guestfs_free_isoinfo_list (struct guestfs_isoinfo_list *);
guestfs_mdstat
struct guestfs_mdstat {
char *mdstat_device;
int32_t mdstat_index;
char *mdstat_flags;
};
struct guestfs_mdstat_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_mdstat *val; /* Elements. */
};
void guestfs_free_mdstat (struct guestfs_mdstat *);
void guestfs_free_mdstat_list (struct guestfs_mdstat_list *);
guestfs_btrfssubvolume
struct guestfs_btrfssubvolume {
uint64_t btrfssubvolume_id;
uint64_t btrfssubvolume_top_level_id;
char *btrfssubvolume_path;
};
struct guestfs_btrfssubvolume_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_btrfssubvolume *val; /* Elements. */
};
void guestfs_free_btrfssubvolume (struct guestfs_btrfssubvolume *);
void guestfs_free_btrfssubvolume_list (struct guestfs_btrfssubvolume_list *);
guestfs_xfsinfo
struct guestfs_xfsinfo {
char *xfs_mntpoint;
uint32_t xfs_inodesize;
uint32_t xfs_agcount;
uint32_t xfs_agsize;
uint32_t xfs_sectsize;
uint32_t xfs_attr;
uint32_t xfs_blocksize;
uint64_t xfs_datablocks;
uint32_t xfs_imaxpct;
uint32_t xfs_sunit;
uint32_t xfs_swidth;
uint32_t xfs_dirversion;
uint32_t xfs_dirblocksize;
uint32_t xfs_cimode;
char *xfs_logname;
uint32_t xfs_logblocksize;
uint32_t xfs_logblocks;
uint32_t xfs_logversion;
uint32_t xfs_logsectsize;
uint32_t xfs_logsunit;
uint32_t xfs_lazycount;
char *xfs_rtname;
uint32_t xfs_rtextsize;
uint64_t xfs_rtblocks;
uint64_t xfs_rtextents;
};
struct guestfs_xfsinfo_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_xfsinfo *val; /* Elements. */
};
void guestfs_free_xfsinfo (struct guestfs_xfsinfo *);
void guestfs_free_xfsinfo_list (struct guestfs_xfsinfo_list *);
guestfs_utsname
struct guestfs_utsname {
char *uts_sysname;
char *uts_release;
char *uts_version;
char *uts_machine;
};
struct guestfs_utsname_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_utsname *val; /* Elements. */
};
void guestfs_free_utsname (struct guestfs_utsname *);
void guestfs_free_utsname_list (struct guestfs_utsname_list *);
guestfs_hivex_node
struct guestfs_hivex_node {
int64_t hivex_node_h;
};
struct guestfs_hivex_node_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_hivex_node *val; /* Elements. */
};
void guestfs_free_hivex_node (struct guestfs_hivex_node *);
void guestfs_free_hivex_node_list (struct guestfs_hivex_node_list *);
guestfs_hivex_value
struct guestfs_hivex_value {
int64_t hivex_value_h;
};
struct guestfs_hivex_value_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_hivex_value *val; /* Elements. */
};
void guestfs_free_hivex_value (struct guestfs_hivex_value *);
void guestfs_free_hivex_value_list (struct guestfs_hivex_value_list *);
guestfs_internal_mountable
struct guestfs_internal_mountable {
int32_t im_type;
char *im_device;
char *im_volume;
};
struct guestfs_internal_mountable_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_internal_mountable *val; /* Elements. */
};
void guestfs_free_internal_mountable (struct guestfs_internal_mountable *);
void guestfs_free_internal_mountable_list (struct guestfs_internal_mountable_list *);
AVAILABILITY
GROUPS OF FUNCTIONALITY IN THE APPLIANCE
Using "guestfs_available" you can test availability of the following groups of functions. This test
queries the appliance to see if the appliance you are currently using supports the functionality.
acl The following functions: "guestfs_acl_delete_def_file" "guestfs_acl_get_file" "guestfs_acl_set_file"
augeas
The following functions: "guestfs_aug_clear" "guestfs_aug_close" "guestfs_aug_defnode"
"guestfs_aug_defvar" "guestfs_aug_get" "guestfs_aug_init" "guestfs_aug_insert" "guestfs_aug_label"
"guestfs_aug_load" "guestfs_aug_ls" "guestfs_aug_match" "guestfs_aug_mv" "guestfs_aug_rm"
"guestfs_aug_save" "guestfs_aug_set" "guestfs_aug_setm"
btrfs
The following functions: "guestfs_btrfs_device_add" "guestfs_btrfs_device_delete"
"guestfs_btrfs_filesystem_balance" "guestfs_btrfs_filesystem_resize" "guestfs_btrfs_filesystem_sync"
"guestfs_btrfs_fsck" "guestfs_btrfs_set_seeding" "guestfs_btrfs_subvolume_create"
"guestfs_btrfs_subvolume_delete" "guestfs_btrfs_subvolume_list" "guestfs_btrfs_subvolume_set_default"
"guestfs_btrfs_subvolume_snapshot" "guestfs_mkfs_btrfs"
extlinux
The following functions: "guestfs_extlinux"
fstrim
The following functions: "guestfs_fstrim"
gdisk
The following functions: "guestfs_part_get_gpt_type" "guestfs_part_set_gpt_type"
grub
The following functions: "guestfs_grub_install"
hivex
The following functions: "guestfs_hivex_close" "guestfs_hivex_commit" "guestfs_hivex_node_add_child"
"guestfs_hivex_node_children" "guestfs_hivex_node_delete_child" "guestfs_hivex_node_get_child"
"guestfs_hivex_node_get_value" "guestfs_hivex_node_name" "guestfs_hivex_node_parent"
"guestfs_hivex_node_set_value" "guestfs_hivex_node_values" "guestfs_hivex_open" "guestfs_hivex_root"
"guestfs_hivex_value_key" "guestfs_hivex_value_type" "guestfs_hivex_value_value"
inotify
The following functions: "guestfs_inotify_add_watch" "guestfs_inotify_close" "guestfs_inotify_files"
"guestfs_inotify_init" "guestfs_inotify_read" "guestfs_inotify_rm_watch"
journal
The following functions: "guestfs_internal_journal_get" "guestfs_journal_close"
"guestfs_journal_get_data_threshold" "guestfs_journal_next" "guestfs_journal_open"
"guestfs_journal_set_data_threshold" "guestfs_journal_skip"
ldm The following functions: "guestfs_ldmtool_create_all" "guestfs_ldmtool_diskgroup_disks"
"guestfs_ldmtool_diskgroup_name" "guestfs_ldmtool_diskgroup_volumes" "guestfs_ldmtool_remove_all"
"guestfs_ldmtool_scan" "guestfs_ldmtool_scan_devices" "guestfs_ldmtool_volume_hint"
"guestfs_ldmtool_volume_partitions" "guestfs_ldmtool_volume_type" "guestfs_list_ldm_partitions"
"guestfs_list_ldm_volumes"
linuxcaps
The following functions: "guestfs_cap_get_file" "guestfs_cap_set_file"
linuxfsuuid
The following functions: "guestfs_mke2fs_JU" "guestfs_mke2journal_U" "guestfs_mkswap_U"
"guestfs_swapoff_uuid" "guestfs_swapon_uuid"
linuxmodules
The following functions: "guestfs_modprobe"
linuxxattrs
The following functions: "guestfs_getxattr" "guestfs_getxattrs" "guestfs_internal_lxattrlist"
"guestfs_lgetxattr" "guestfs_lgetxattrs" "guestfs_lremovexattr" "guestfs_lsetxattr"
"guestfs_removexattr" "guestfs_setxattr"
luks
The following functions: "guestfs_luks_add_key" "guestfs_luks_close" "guestfs_luks_format"
"guestfs_luks_format_cipher" "guestfs_luks_kill_slot" "guestfs_luks_open" "guestfs_luks_open_ro"
lvm2
The following functions: "guestfs_lvcreate" "guestfs_lvcreate_free" "guestfs_lvm_remove_all"
"guestfs_lvm_set_filter" "guestfs_lvremove" "guestfs_lvresize" "guestfs_lvresize_free" "guestfs_lvs"
"guestfs_lvs_full" "guestfs_pvchange_uuid" "guestfs_pvchange_uuid_all" "guestfs_pvcreate"
"guestfs_pvremove" "guestfs_pvresize" "guestfs_pvresize_size" "guestfs_pvs" "guestfs_pvs_full"
"guestfs_vg_activate" "guestfs_vg_activate_all" "guestfs_vgchange_uuid" "guestfs_vgchange_uuid_all"
"guestfs_vgcreate" "guestfs_vgmeta" "guestfs_vgremove" "guestfs_vgs" "guestfs_vgs_full"
mdadm
The following functions: "guestfs_md_create" "guestfs_md_detail" "guestfs_md_stat" "guestfs_md_stop"
mknod
The following functions: "guestfs_mkfifo" "guestfs_mknod" "guestfs_mknod_b" "guestfs_mknod_c"
ntfs3g
The following functions: "guestfs_ntfs_3g_probe" "guestfs_ntfsclone_in" "guestfs_ntfsclone_out"
"guestfs_ntfsfix"
ntfsprogs
The following functions: "guestfs_ntfsresize" "guestfs_ntfsresize_size"
realpath
The following functions: "guestfs_realpath"
rsync
The following functions: "guestfs_rsync" "guestfs_rsync_in" "guestfs_rsync_out"
scrub
The following functions: "guestfs_scrub_device" "guestfs_scrub_file" "guestfs_scrub_freespace"
selinux
The following functions: "guestfs_getcon" "guestfs_setcon"
syslinux
The following functions: "guestfs_syslinux"
wipefs
The following functions: "guestfs_wipefs"
xfs The following functions: "guestfs_xfs_admin" "guestfs_xfs_growfs" "guestfs_xfs_info"
"guestfs_xfs_repair"
xz The following functions: "guestfs_txz_in" "guestfs_txz_out"
zerofree
The following functions: "guestfs_zerofree"
FILESYSTEM AVAILABLE
The "guestfs_filesystem_available" call tests whether a filesystem type is supported by the appliance
kernel.
This is mainly useful as a negative test. If this returns true, it doesn't mean that a particular
filesystem can be mounted, since filesystems can fail for other reasons such as it being a later version
of the filesystem, or having incompatible features.
GUESTFISH supported COMMAND
In guestfish(3) there is a handy interactive command "supported" which prints out the available groups
and whether they are supported by this build of libguestfs. Note however that you have to do "run"
first.
SINGLE CALLS AT COMPILE TIME
Since version 1.5.8, "<guestfs.h>" defines symbols for each C API function, such as:
#define GUESTFS_HAVE_DD 1
if "guestfs_dd" is available.
Before version 1.5.8, if you needed to test whether a single libguestfs function is available at compile
time, we recommended using build tools such as autoconf or cmake. For example in autotools you could
use:
AC_CHECK_LIB([guestfs],[guestfs_create])
AC_CHECK_FUNCS([guestfs_dd])
which would result in "HAVE_GUESTFS_DD" being either defined or not defined in your program.
SINGLE CALLS AT RUN TIME
Testing at compile time doesn't guarantee that a function really exists in the library. The reason is
that you might be dynamically linked against a previous libguestfs.so (dynamic library) which doesn't
have the call. This situation unfortunately results in a segmentation fault, which is a shortcoming of
the C dynamic linking system itself.
You can use dlopen(3) to test if a function is available at run time, as in this example program (note
that you still need the compile time check as well):
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dlfcn.h>
#include <guestfs.h>
main ()
{
#ifdef GUESTFS_HAVE_DD
void *dl;
int has_function;
/* Test if the function guestfs_dd is really available. */
dl = dlopen (NULL, RTLD_LAZY);
if (!dl) {
fprintf (stderr, "dlopen: %s\n", dlerror ());
exit (EXIT_FAILURE);
}
has_function = dlsym (dl, "guestfs_dd") != NULL;
dlclose (dl);
if (!has_function)
printf ("this libguestfs.so does NOT have guestfs_dd function\n");
else {
printf ("this libguestfs.so has guestfs_dd function\n");
/* Now it's safe to call
guestfs_dd (g, "foo", "bar");
*/
}
#else
printf ("guestfs_dd function was not found at compile time\n");
#endif
}
You may think the above is an awful lot of hassle, and it is. There are other ways outside of the C
linking system to ensure that this kind of incompatibility never arises, such as using package
versioning:
Requires: libguestfs >= 1.0.80
CALLS WITH OPTIONAL ARGUMENTS
A recent feature of the API is the introduction of calls which take optional arguments. In C these are
declared 3 ways. The main way is as a call which takes variable arguments (ie. "..."), as in this
example:
int guestfs_add_drive_opts (guestfs_h *g, const char *filename, ...);
Call this with a list of optional arguments, terminated by "-1". So to call with no optional arguments
specified:
guestfs_add_drive_opts (g, filename, -1);
With a single optional argument:
guestfs_add_drive_opts (g, filename,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "qcow2",
-1);
With two:
guestfs_add_drive_opts (g, filename,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "qcow2",
GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
-1);
and so forth. Don't forget the terminating "-1" otherwise Bad Things will happen!
USING va_list FOR OPTIONAL ARGUMENTS
The second variant has the same name with the suffix "_va", which works the same way but takes a
"va_list". See the C manual for details. For the example function, this is declared:
int guestfs_add_drive_opts_va (guestfs_h *g, const char *filename,
va_list args);
CONSTRUCTING OPTIONAL ARGUMENTS
The third variant is useful where you need to construct these calls. You pass in a structure where you
fill in the optional fields. The structure has a bitmask as the first element which you must set to
indicate which fields you have filled in. For our example function the structure and call are declared:
struct guestfs_add_drive_opts_argv {
uint64_t bitmask;
int readonly;
const char *format;
/* ... */
};
int guestfs_add_drive_opts_argv (guestfs_h *g, const char *filename,
const struct guestfs_add_drive_opts_argv *optargs);
You could call it like this:
struct guestfs_add_drive_opts_argv optargs = {
.bitmask = GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK |
GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK,
.readonly = 1,
.format = "qcow2"
};
guestfs_add_drive_opts_argv (g, filename, &optargs);
Notes:
• The "_BITMASK" suffix on each option name when specifying the bitmask.
• You do not need to fill in all fields of the structure.
• There must be a one-to-one correspondence between fields of the structure that are filled in, and
bits set in the bitmask.
OPTIONAL ARGUMENTS IN OTHER LANGUAGES
In other languages, optional arguments are expressed in the way that is natural for that language. We
refer you to the language-specific documentation for more details on that.
For guestfish, see "OPTIONAL ARGUMENTS" in guestfish(1).
EVENTS
SETTING CALLBACKS TO HANDLE EVENTS
Note: This section documents the generic event mechanism introduced in libguestfs 1.10, which you should
use in new code if possible. The old functions "guestfs_set_log_message_callback",
"guestfs_set_subprocess_quit_callback", "guestfs_set_launch_done_callback", "guestfs_set_close_callback"
and "guestfs_set_progress_callback" are no longer documented in this manual page. Because of the ABI
guarantee, the old functions continue to work.
Handles generate events when certain things happen, such as log messages being generated, progress
messages during long-running operations, or the handle being closed. The API calls described below let
you register a callback to be called when events happen. You can register multiple callbacks (for the
same, different or overlapping sets of events), and individually remove callbacks. If callbacks are not
removed, then they remain in force until the handle is closed.
In the current implementation, events are only generated synchronously: that means that events (and hence
callbacks) can only happen while you are in the middle of making another libguestfs call. The callback
is called in the same thread.
Events may contain a payload, usually nothing (void), an array of 64 bit unsigned integers, or a message
buffer. Payloads are discussed later on.
CLASSES OF EVENTS
GUESTFS_EVENT_CLOSE (payload type: void)
The callback function will be called while the handle is being closed (synchronously from
"guestfs_close").
Note that libguestfs installs an atexit(3) handler to try to clean up handles that are open when the
program exits. This means that this callback might be called indirectly from exit(3), which can
cause unexpected problems in higher-level languages (eg. if your HLL interpreter has already been
cleaned up by the time this is called, and if your callback then jumps into some HLL function).
If no callback is registered: the handle is closed without any callback being invoked.
GUESTFS_EVENT_SUBPROCESS_QUIT (payload type: void)
The callback function will be called when the child process quits, either asynchronously or if killed
by "guestfs_kill_subprocess". (This corresponds to a transition from any state to the CONFIG state).
If no callback is registered: the event is ignored.
GUESTFS_EVENT_LAUNCH_DONE (payload type: void)
The callback function will be called when the child process becomes ready first time after it has
been launched. (This corresponds to a transition from LAUNCHING to the READY state).
If no callback is registered: the event is ignored.
GUESTFS_EVENT_PROGRESS (payload type: array of 4 x uint64_t)
Some long-running operations can generate progress messages. If this callback is registered, then it
will be called each time a progress message is generated (usually two seconds after the operation
started, and three times per second thereafter until it completes, although the frequency may change
in future versions).
The callback receives in the payload four unsigned 64 bit numbers which are (in order): "proc_nr",
"serial", "position", "total".
The units of "total" are not defined, although for some operations "total" may relate in some way to
the amount of data to be transferred (eg. in bytes or megabytes), and "position" may be the portion
which has been transferred.
The only defined and stable parts of the API are:
• The callback can display to the user some type of progress bar or indicator which shows the ratio
of "position":"total".
• 0 <= "position" <= "total"
• If any progress notification is sent during a call, then a final progress notification is always
sent when "position" = "total" (unless the call fails with an error).
This is to simplify caller code, so callers can easily set the progress indicator to "100%" at
the end of the operation, without requiring special code to detect this case.
• For some calls we are unable to estimate the progress of the call, but we can still generate
progress messages to indicate activity. This is known as "pulse mode", and is directly supported
by certain progress bar implementations (eg. GtkProgressBar).
For these calls, zero or more progress messages are generated with "position = 0" and "total =
1", followed by a final message with "position = total = 1".
As noted above, if the call fails with an error then the final message may not be generated.
The callback also receives the procedure number ("proc_nr") and serial number ("serial") of the call.
These are only useful for debugging protocol issues, and the callback can normally ignore them. The
callback may want to print these numbers in error messages or debugging messages.
If no callback is registered: progress messages are discarded.
GUESTFS_EVENT_APPLIANCE (payload type: message buffer)
The callback function is called whenever a log message is generated by qemu, the appliance kernel,
guestfsd (daemon), or utility programs.
If the verbose flag ("guestfs_set_verbose") is set before launch ("guestfs_launch") then additional
debug messages are generated.
If no callback is registered: the messages are discarded unless the verbose flag is set in which case
they are sent to stderr. You can override the printing of verbose messages to stderr by setting up a
callback.
GUESTFS_EVENT_LIBRARY (payload type: message buffer)
The callback function is called whenever a log message is generated by the library part of
libguestfs.
If the verbose flag ("guestfs_set_verbose") is set then additional debug messages are generated.
If no callback is registered: the messages are discarded unless the verbose flag is set in which case
they are sent to stderr. You can override the printing of verbose messages to stderr by setting up a
callback.
GUESTFS_EVENT_WARNING (payload type: message buffer)
The callback function is called whenever a warning message is generated by the library part of
libguestfs.
If no callback is registered: the messages are printed to stderr. You can override the printing of
warning messages to stderr by setting up a callback.
GUESTFS_EVENT_TRACE (payload type: message buffer)
The callback function is called whenever a trace message is generated. This only applies if the
trace flag ("guestfs_set_trace") is set.
If no callback is registered: the messages are sent to stderr. You can override the printing of
trace messages to stderr by setting up a callback.
GUESTFS_EVENT_ENTER (payload type: function name)
The callback function is called whenever a libguestfs function is entered.
The payload is a string which contains the name of the function that we are entering (not including
"guestfs_" prefix).
Note that libguestfs functions can call themselves, so you may see many events from a single call. A
few libguestfs functions do not generate this event.
If no callback is registered: the event is ignored.
GUESTFS_EVENT_LIBVIRT_AUTH (payload type: libvirt URI)
For any API function that opens a libvirt connection, this event may be generated to indicate that
libvirt demands authentication information. See "LIBVIRT AUTHENTICATION" below.
If no callback is registered: "virConnectAuthPtrDefault" is used (suitable for command-line programs
only).
EVENT API
guestfs_set_event_callback
int guestfs_set_event_callback (guestfs_h *g,
guestfs_event_callback cb,
uint64_t event_bitmask,
int flags,
void *opaque);
This function registers a callback ("cb") for all event classes in the "event_bitmask".
For example, to register for all log message events, you could call this function with the bitmask
"GUESTFS_EVENT_APPLIANCE|GUESTFS_EVENT_LIBRARY|GUESTFS_EVENT_WARNING". To register a single callback for
all possible classes of events, use "GUESTFS_EVENT_ALL".
"flags" should always be passed as 0.
"opaque" is an opaque pointer which is passed to the callback. You can use it for any purpose.
The return value is the event handle (an integer) which you can use to delete the callback (see below).
If there is an error, this function returns "-1", and sets the error in the handle in the usual way (see
"guestfs_last_error" etc.)
Callbacks remain in effect until they are deleted, or until the handle is closed.
In the case where multiple callbacks are registered for a particular event class, all of the callbacks
are called. The order in which multiple callbacks are called is not defined.
guestfs_delete_event_callback
void guestfs_delete_event_callback (guestfs_h *g, int event_handle);
Delete a callback that was previously registered. "event_handle" should be the integer that was returned
by a previous call to "guestfs_set_event_callback" on the same handle.
guestfs_event_to_string
char *guestfs_event_to_string (uint64_t event);
"event" is either a single event or a bitmask of events. This returns a string representation (useful
for debugging or printing events).
A single event is returned as the name in lower case, eg. "close".
A bitmask of several events is returned as a comma-separated list, eg. "close,progress".
If zero is passed, then the empty string "" is returned.
On success this returns a string. On error it returns NULL and sets "errno".
The returned string must be freed by the caller.
guestfs_event_callback
typedef void (*guestfs_event_callback) (
guestfs_h *g,
void *opaque,
uint64_t event,
int event_handle,
int flags,
const char *buf, size_t buf_len,
const uint64_t *array, size_t array_len);
This is the type of the event callback function that you have to provide.
The basic parameters are: the handle ("g"), the opaque user pointer ("opaque"), the event class (eg.
"GUESTFS_EVENT_PROGRESS"), the event handle, and "flags" which in the current API you should ignore.
The remaining parameters contain the event payload (if any). Each event may contain a payload, which
usually relates to the event class, but for future proofing your code should be written to handle any
payload for any event class.
"buf" and "buf_len" contain a message buffer (if "buf_len == 0", then there is no message buffer). Note
that this message buffer can contain arbitrary 8 bit data, including NUL bytes.
"array" and "array_len" is an array of 64 bit unsigned integers. At the moment this is only used for
progress messages.
EXAMPLE: CAPTURING LOG MESSAGES
A working program demonstrating this can be found in "examples/debug-logging.c" in the source of
libguestfs.
One motivation for the generic event API was to allow GUI programs to capture debug and other messages.
In libguestfs ≤ 1.8 these were sent unconditionally to "stderr".
Events associated with log messages are: "GUESTFS_EVENT_LIBRARY", "GUESTFS_EVENT_APPLIANCE",
"GUESTFS_EVENT_WARNING" and "GUESTFS_EVENT_TRACE". (Note that error messages are not events; you must
capture error messages separately).
Programs have to set up a callback to capture the classes of events of interest:
int eh =
guestfs_set_event_callback
(g, message_callback,
GUESTFS_EVENT_LIBRARY | GUESTFS_EVENT_APPLIANCE |
GUESTFS_EVENT_WARNING | GUESTFS_EVENT_TRACE,
0, NULL) == -1)
if (eh == -1) {
// handle error in the usual way
}
The callback can then direct messages to the appropriate place. In this example, messages are directed
to syslog:
static void
message_callback (
guestfs_h *g,
void *opaque,
uint64_t event,
int event_handle,
int flags,
const char *buf, size_t buf_len,
const uint64_t *array, size_t array_len)
{
const int priority = LOG_USER|LOG_INFO;
if (buf_len > 0)
syslog (priority, "event 0x%lx: %s", event, buf);
}
LIBVIRT AUTHENTICATION
Some libguestfs API calls can open libvirt connections. Currently the only ones are
"guestfs_add_domain"; and "guestfs_launch" if the libvirt backend has been selected. Libvirt connections
may require authentication, for example if they need to access a remote server or to access root services
from non-root. Libvirt authentication happens via a callback mechanism, see
http://libvirt.org/guide/html/Application_Development_Guide-Connections.html
You may provide libvirt authentication data by registering a callback for events of type
"GUESTFS_EVENT_LIBVIRT_AUTH".
If no such event is registered, then libguestfs uses a libvirt function that provides command-line
prompts ("virConnectAuthPtrDefault"). This is only suitable for command-line libguestfs programs.
To provide authentication, first call "guestfs_set_libvirt_supported_credentials" with the list of
credentials your program knows how to provide. Second, register a callback for the
"GUESTFS_EVENT_LIBVIRT_AUTH" event. The event handler will be called when libvirt is requesting
authentication information.
In the event handler, call "guestfs_get_libvirt_requested_credentials" to get a list of the credentials
that libvirt is asking for. You then need to ask (eg. the user) for each credential, and call
"guestfs_set_libvirt_requested_credential" with the answer. Note that for each credential, additional
information may be available via the calls "guestfs_get_libvirt_requested_credential_prompt",
"guestfs_get_libvirt_requested_credential_challenge" or
"guestfs_get_libvirt_requested_credential_defresult".
The example program below should make this clearer.
There is also a more substantial working example program supplied with the libguestfs sources, called
"libvirt-auth.c".
main ()
{
guestfs_h *g;
char *creds[] = { "authname", "passphrase", NULL };
int r, eh;
g = guestfs_create ();
if (!g) exit (EXIT_FAILURE);
/* Tell libvirt what credentials the program supports. */
r = guestfs_set_libvirt_supported_credentials (g, creds);
if (r == -1)
exit (EXIT_FAILURE);
/* Set up the event handler. */
eh = guestfs_set_event_callback (
g, do_auth,
GUESTFS_EVENT_LIBVIRT_AUTH, 0, NULL);
if (eh == -1)
exit (EXIT_FAILURE);
/* An example of a call that may ask for credentials. */
r = guestfs_add_domain (
g, "dom",
GUESTFS_ADD_DOMAIN_LIBVIRTURI, "qemu:///system",
-1);
if (r == -1)
exit (EXIT_FAILURE);
exit (EXIT_SUCCESS);
}
static void
do_auth (guestfs_h *g,
void *opaque,
uint64_t event,
int event_handle,
int flags,
const char *buf, size_t buf_len,
const uint64_t *array, size_t array_len)
{
char **creds;
size_t i;
char *prompt;
char *reply;
size_t replylen;
int r;
// buf will be the libvirt URI. buf_len may be ignored.
printf ("Authentication required for libvirt conn '%s'\n",
buf);
// Ask libguestfs what credentials libvirt is demanding.
creds = guestfs_get_libvirt_requested_credentials (g);
if (creds == NULL)
exit (EXIT_FAILURE);
// Now ask the user for answers.
for (i = 0; creds[i] != NULL; ++i)
{
if (strcmp (creds[i], "authname") == 0 ||
strcmp (creds[i], "passphrase") == 0)
{
prompt =
guestfs_get_libvirt_requested_credential_prompt (g, i);
if (prompt && strcmp (prompt, "") != 0)
printf ("%s: ", prompt);
free (prompt);
// Some code here to ask for the credential.
// ...
// Put the reply in 'reply', length 'replylen' (bytes).
r = guestfs_set_libvirt_requested_credential (g, i,
reply, replylen);
if (r == -1)
exit (EXIT_FAILURE);
}
free (creds[i]);
}
free (creds);
}
CANCELLING LONG TRANSFERS
Some operations can be cancelled by the caller while they are in progress. Currently only operations
that involve uploading or downloading data can be cancelled (technically: operations that have "FileIn"
or "FileOut" parameters in the generator).
To cancel the transfer, call "guestfs_user_cancel". For more information, read the description of
"guestfs_user_cancel".
PRIVATE DATA AREA
You can attach named pieces of private data to the libguestfs handle, fetch them by name, and walk over
them, for the lifetime of the handle. This is called the private data area and is only available from
the C API.
To attach a named piece of data, use the following call:
void guestfs_set_private (guestfs_h *g, const char *key, void *data);
"key" is the name to associate with this data, and "data" is an arbitrary pointer (which can be "NULL").
Any previous item with the same key is overwritten.
You can use any "key" string you want, but avoid keys beginning with an underscore character (libguestfs
uses those for its own internal purposes, such as implementing language bindings). It is recommended
that you prefix the key with some unique string to avoid collisions with other users.
To retrieve the pointer, use:
void *guestfs_get_private (guestfs_h *g, const char *key);
This function returns "NULL" if either no data is found associated with "key", or if the user previously
set the "key"'s "data" pointer to "NULL".
Libguestfs does not try to look at or interpret the "data" pointer in any way. As far as libguestfs is
concerned, it need not be a valid pointer at all. In particular, libguestfs does not try to free the
data when the handle is closed. If the data must be freed, then the caller must either free it before
calling "guestfs_close" or must set up a close callback to do it (see "GUESTFS_EVENT_CLOSE").
To walk over all entries, use these two functions:
void *guestfs_first_private (guestfs_h *g, const char **key_rtn);
void *guestfs_next_private (guestfs_h *g, const char **key_rtn);
"guestfs_first_private" returns the first key, pointer pair ("first" does not have any particular meaning
-- keys are not returned in any defined order). A pointer to the key is returned in *key_rtn and the
corresponding data pointer is returned from the function. "NULL" is returned if there are no keys stored
in the handle.
"guestfs_next_private" returns the next key, pointer pair. The return value of this function is "NULL"
if there are no further entries to return.
Notes about walking over entries:
• You must not call "guestfs_set_private" while walking over the entries.
• The handle maintains an internal iterator which is reset when you call "guestfs_first_private". This
internal iterator is invalidated when you call "guestfs_set_private".
• If you have set the data pointer associated with a key to "NULL", ie:
guestfs_set_private (g, key, NULL);
then that "key" is not returned when walking.
• *key_rtn is only valid until the next call to "guestfs_first_private", "guestfs_next_private" or
"guestfs_set_private".
The following example code shows how to print all keys and data pointers that are associated with the
handle "g":
const char *key;
void *data = guestfs_first_private (g, &key);
while (data != NULL)
{
printf ("key = %s, data = %p\n", key, data);
data = guestfs_next_private (g, &key);
}
More commonly you are only interested in keys that begin with an application-specific prefix "foo_".
Modify the loop like so:
const char *key;
void *data = guestfs_first_private (g, &key);
while (data != NULL)
{
if (strncmp (key, "foo_", strlen ("foo_")) == 0)
printf ("key = %s, data = %p\n", key, data);
data = guestfs_next_private (g, &key);
}
If you need to modify keys while walking, then you have to jump back to the beginning of the loop. For
example, to delete all keys prefixed with "foo_":
const char *key;
void *data;
again:
data = guestfs_first_private (g, &key);
while (data != NULL)
{
if (strncmp (key, "foo_", strlen ("foo_")) == 0)
{
guestfs_set_private (g, key, NULL);
/* note that 'key' pointer is now invalid, and so is
the internal iterator */
goto again;
}
data = guestfs_next_private (g, &key);
}
Note that the above loop is guaranteed to terminate because the keys are being deleted, but other
manipulations of keys within the loop might not terminate unless you also maintain an indication of which
keys have been visited.
SYSTEMTAP
The libguestfs C library can be probed using systemtap or DTrace. This is true of any library, not just
libguestfs. However libguestfs also contains static markers to help in probing internal operations.
You can list all the static markers by doing:
stap -l 'process("/usr/lib*/libguestfs.so.0")
.provider("guestfs").mark("*")'
Note: These static markers are not part of the stable API and may change in future versions.
SYSTEMTAP SCRIPT EXAMPLE
This script contains examples of displaying both the static markers and some ordinary C entry points:
global last;
function display_time () {
now = gettimeofday_us ();
delta = 0;
if (last > 0)
delta = now - last;
last = now;
printf ("%d (+%d):", now, delta);
}
probe begin {
last = 0;
printf ("ready\n");
}
/* Display all calls to static markers. */
probe process("/usr/lib*/libguestfs.so.0")
.provider("guestfs").mark("*") ? {
display_time();
printf ("\t%s %s\n", $$name, $$parms);
}
/* Display all calls to guestfs_mkfs* functions. */
probe process("/usr/lib*/libguestfs.so.0")
.function("guestfs_mkfs*") ? {
display_time();
printf ("\t%s %s\n", probefunc(), $$parms);
}
The script above can be saved to "test.stap" and run using the stap(1) program. Note that you either
have to be root, or you have to add yourself to several special stap groups. Consult the systemtap
documentation for more information.
# stap /tmp/test.stap
ready
In another terminal, run a guestfish command such as this:
guestfish -N fs
In the first terminal, stap trace output similar to this is shown:
1318248056692655 (+0): launch_start
1318248056692850 (+195): launch_build_appliance_start
1318248056818285 (+125435): launch_build_appliance_end
1318248056838059 (+19774): launch_run_qemu
1318248061071167 (+4233108): launch_end
1318248061280324 (+209157): guestfs_mkfs g=0x1024ab0 fstype=0x46116f device=0x1024e60
ARCHITECTURE
Internally, libguestfs is implemented by running an appliance (a special type of small virtual machine)
using qemu(1). Qemu runs as a child process of the main program.
___________________
/ \
| main program |
| |
| | child process / appliance
| | __________________________
| | / qemu \
+-------------------+ RPC | +-----------------+ |
| libguestfs <--------------------> guestfsd | |
| | | +-----------------+ |
\___________________/ | | Linux kernel | |
| +--^--------------+ |
\_________|________________/
|
_______v______
/ \
| Device or |
| disk image |
\______________/
The library, linked to the main program, creates the child process and hence the appliance in the
"guestfs_launch" function.
Inside the appliance is a Linux kernel and a complete stack of userspace tools (such as LVM and ext2
programs) and a small controlling daemon called "guestfsd". The library talks to "guestfsd" using remote
procedure calls (RPC). There is a mostly one-to-one correspondence between libguestfs API calls and RPC
calls to the daemon. Lastly the disk image(s) are attached to the qemu process which translates device
access by the appliance's Linux kernel into accesses to the image.
A common misunderstanding is that the appliance "is" the virtual machine. Although the disk image you
are attached to might also be used by some virtual machine, libguestfs doesn't know or care about this.
(But you will care if both libguestfs's qemu process and your virtual machine are trying to update the
disk image at the same time, since these usually results in massive disk corruption).
STATE MACHINE
libguestfs uses a state machine to model the child process:
|
guestfs_create / guestfs_create_flags
|
|
____V_____
/ \
| CONFIG |
\__________/
^ ^ \
| \ \ guestfs_launch
| _\__V______
| / \
| | LAUNCHING |
| \___________/
| /
| guestfs_launch
| /
__|____V
/ \
| READY |
\________/
The normal transitions are (1) CONFIG (when the handle is created, but there is no child process), (2)
LAUNCHING (when the child process is booting up), (3) READY meaning the appliance is up, actions can be
issued to, and carried out by, the child process.
The guest may be killed by "guestfs_kill_subprocess", or may die asynchronously at any time (eg. due to
some internal error), and that causes the state to transition back to CONFIG.
Configuration commands for qemu such as "guestfs_set_path" can only be issued when in the CONFIG state.
The API offers one call that goes from CONFIG through LAUNCHING to READY. "guestfs_launch" blocks until
the child process is READY to accept commands (or until some failure or timeout). "guestfs_launch"
internally moves the state from CONFIG to LAUNCHING while it is running.
API actions such as "guestfs_mount" can only be issued when in the READY state. These API calls block
waiting for the command to be carried out. There are no non-blocking versions, and no way to issue more
than one command per handle at the same time.
Finally, the child process sends asynchronous messages back to the main program, such as kernel log
messages. You can register a callback to receive these messages.
INTERNALS
APPLIANCE BOOT PROCESS
This process has evolved and continues to evolve. The description here corresponds only to the current
version of libguestfs and is provided for information only.
In order to follow the stages involved below, enable libguestfs debugging (set the environment variable
"LIBGUESTFS_DEBUG=1").
Create the appliance
"supermin-helper" is invoked to create the kernel, a small initrd and the appliance.
The appliance is cached in "/var/tmp/.guestfs-<UID>" (or in another directory if
"LIBGUESTFS_CACHEDIR" or "TMPDIR" are set).
For a complete description of how the appliance is created and cached, read the supermin(8) and
supermin-helper(8) man pages.
Start qemu and boot the kernel
qemu is invoked to boot the kernel.
Run the initrd
"supermin-helper" builds a small initrd. The initrd is not the appliance. The purpose of the initrd
is to load enough kernel modules in order that the appliance itself can be mounted and started.
The initrd is a cpio archive called "/var/tmp/.guestfs-<UID>/initrd".
When the initrd has started you will see messages showing that kernel modules are being loaded,
similar to this:
supermin: ext2 mini initrd starting up
supermin: mounting /sys
supermin: internal insmod libcrc32c.ko
supermin: internal insmod crc32c-intel.ko
Find and mount the appliance device
The appliance is a sparse file containing an ext2 filesystem which contains a familiar (although
reduced in size) Linux operating system. It would normally be called "/var/tmp/.guestfs-<UID>/root".
The regular disks being inspected by libguestfs are the first devices exposed by qemu (eg. as
"/dev/vda").
The last disk added to qemu is the appliance itself (eg. "/dev/vdb" if there was only one regular
disk).
Thus the final job of the initrd is to locate the appliance disk, mount it, and switch root into the
appliance, and run "/init" from the appliance.
If this works successfully you will see messages such as:
supermin: picked /sys/block/vdb/dev as root device
supermin: creating /dev/root as block special 252:16
supermin: mounting new root on /root
supermin: chroot
Starting /init script ...
Note that "Starting /init script ..." indicates that the appliance's init script is now running.
Initialize the appliance
The appliance itself now initializes itself. This involves starting certain processes like "udev",
possibly printing some debug information, and finally running the daemon ("guestfsd").
The daemon
Finally the daemon ("guestfsd") runs inside the appliance. If it runs you should see:
verbose daemon enabled
The daemon expects to see a named virtio-serial port exposed by qemu and connected on the other end
to the library.
The daemon connects to this port (and hence to the library) and sends a four byte message
"GUESTFS_LAUNCH_FLAG", which initiates the communication protocol (see below).
COMMUNICATION PROTOCOL
Don't rely on using this protocol directly. This section documents how it currently works, but it may
change at any time.
The protocol used to talk between the library and the daemon running inside the qemu virtual machine is a
simple RPC mechanism built on top of XDR (RFC 1014, RFC 1832, RFC 4506).
The detailed format of structures is in "src/guestfs_protocol.x" (note: this file is automatically
generated).
There are two broad cases, ordinary functions that don't have any "FileIn" and "FileOut" parameters,
which are handled with very simple request/reply messages. Then there are functions that have any
"FileIn" or "FileOut" parameters, which use the same request and reply messages, but they may also be
followed by files sent using a chunked encoding.
ORDINARY FUNCTIONS (NO FILEIN/FILEOUT PARAMS)
For ordinary functions, the request message is:
total length (header + arguments,
but not including the length word itself)
struct guestfs_message_header (encoded as XDR)
struct guestfs_<foo>_args (encoded as XDR)
The total length field allows the daemon to allocate a fixed size buffer into which it slurps the rest of
the message. As a result, the total length is limited to "GUESTFS_MESSAGE_MAX" bytes (currently 4MB),
which means the effective size of any request is limited to somewhere under this size.
Note also that many functions don't take any arguments, in which case the "guestfs_foo_args" is
completely omitted.
The header contains the procedure number ("guestfs_proc") which is how the receiver knows what type of
args structure to expect, or none at all.
For functions that take optional arguments, the optional arguments are encoded in the "guestfs_foo_args"
structure in the same way as ordinary arguments. A bitmask in the header indicates which optional
arguments are meaningful. The bitmask is also checked to see if it contains bits set which the daemon
does not know about (eg. if more optional arguments were added in a later version of the library), and
this causes the call to be rejected.
The reply message for ordinary functions is:
total length (header + ret,
but not including the length word itself)
struct guestfs_message_header (encoded as XDR)
struct guestfs_<foo>_ret (encoded as XDR)
As above the "guestfs_foo_ret" structure may be completely omitted for functions that return no formal
return values.
As above the total length of the reply is limited to "GUESTFS_MESSAGE_MAX".
In the case of an error, a flag is set in the header, and the reply message is slightly changed:
total length (header + error,
but not including the length word itself)
struct guestfs_message_header (encoded as XDR)
struct guestfs_message_error (encoded as XDR)
The "guestfs_message_error" structure contains the error message as a string.
FUNCTIONS THAT HAVE FILEIN PARAMETERS
A "FileIn" parameter indicates that we transfer a file into the guest. The normal request message is
sent (see above). However this is followed by a sequence of file chunks.
total length (header + arguments,
but not including the length word itself,
and not including the chunks)
struct guestfs_message_header (encoded as XDR)
struct guestfs_<foo>_args (encoded as XDR)
sequence of chunks for FileIn param #0
sequence of chunks for FileIn param #1 etc.
The "sequence of chunks" is:
length of chunk (not including length word itself)
struct guestfs_chunk (encoded as XDR)
length of chunk
struct guestfs_chunk (encoded as XDR)
...
length of chunk
struct guestfs_chunk (with data.data_len == 0)
The final chunk has the "data_len" field set to zero. Additionally a flag is set in the final chunk to
indicate either successful completion or early cancellation.
At time of writing there are no functions that have more than one FileIn parameter. However this is
(theoretically) supported, by sending the sequence of chunks for each FileIn parameter one after another
(from left to right).
Both the library (sender) and the daemon (receiver) may cancel the transfer. The library does this by
sending a chunk with a special flag set to indicate cancellation. When the daemon sees this, it cancels
the whole RPC, does not send any reply, and goes back to reading the next request.
The daemon may also cancel. It does this by writing a special word "GUESTFS_CANCEL_FLAG" to the socket.
The library listens for this during the transfer, and if it gets it, it will cancel the transfer (it
sends a cancel chunk). The special word is chosen so that even if cancellation happens right at the end
of the transfer (after the library has finished writing and has started listening for the reply), the
"spurious" cancel flag will not be confused with the reply message.
This protocol allows the transfer of arbitrary sized files (no 32 bit limit), and also files where the
size is not known in advance (eg. from pipes or sockets). However the chunks are rather small
("GUESTFS_MAX_CHUNK_SIZE"), so that neither the library nor the daemon need to keep much in memory.
FUNCTIONS THAT HAVE FILEOUT PARAMETERS
The protocol for FileOut parameters is exactly the same as for FileIn parameters, but with the roles of
daemon and library reversed.
total length (header + ret,
but not including the length word itself,
and not including the chunks)
struct guestfs_message_header (encoded as XDR)
struct guestfs_<foo>_ret (encoded as XDR)
sequence of chunks for FileOut param #0
sequence of chunks for FileOut param #1 etc.
INITIAL MESSAGE
When the daemon launches it sends an initial word ("GUESTFS_LAUNCH_FLAG") which indicates that the guest
and daemon is alive. This is what "guestfs_launch" waits for.
PROGRESS NOTIFICATION MESSAGES
The daemon may send progress notification messages at any time. These are distinguished by the normal
length word being replaced by "GUESTFS_PROGRESS_FLAG", followed by a fixed size progress message.
The library turns them into progress callbacks (see "GUESTFS_EVENT_PROGRESS") if there is a callback
registered, or discards them if not.
The daemon self-limits the frequency of progress messages it sends (see
"daemon/proto.c:notify_progress"). Not all calls generate progress messages.
LIBGUESTFS VERSION NUMBERS
Since April 2010, libguestfs has started to make separate development and stable releases, along with
corresponding branches in our git repository. These separate releases can be identified by version
number:
even numbers for stable: 1.2.x, 1.4.x, ...
.-------- odd numbers for development: 1.3.x, 1.5.x, ...
|
v
1 . 3 . 5
^ ^
| |
| `-------- sub-version
|
`------ always '1' because we don't change the ABI
Thus "1.3.5" is the 5th update to the development branch "1.3".
As time passes we cherry pick fixes from the development branch and backport those into the stable
branch, the effect being that the stable branch should get more stable and less buggy over time. So the
stable releases are ideal for people who don't need new features but would just like the software to
work.
Our criteria for backporting changes are:
• Documentation changes which don't affect any code are backported unless the documentation refers to a
future feature which is not in stable.
• Bug fixes which are not controversial, fix obvious problems, and have been well tested are
backported.
• Simple rearrangements of code which shouldn't affect how it works get backported. This is so that
the code in the two branches doesn't get too far out of step, allowing us to backport future fixes
more easily.
• We don't backport new features, new APIs, new tools etc, except in one exceptional case: the new
feature is required in order to implement an important bug fix.
A new stable branch starts when we think the new features in development are substantial and compelling
enough over the current stable branch to warrant it. When that happens we create new stable and
development versions 1.N.0 and 1.(N+1).0 [N is even]. The new dot-oh release won't necessarily be so
stable at this point, but by backporting fixes from development, that branch will stabilize over time.
EXTENDING LIBGUESTFS
This section is for hackers who want to extend libguestfs itself.
OVERVIEW OF THE SOURCE CODE
Libguestfs source is located in the github repository https://github.com/libguestfs/libguestfs
Large amounts of boilerplate code in libguestfs (RPC, bindings, documentation) are generated. This means
that many source files will appear to be missing from a straightforward git checkout. You have to run
the generator ("./autogen.sh && make -C generator") in order to create those files.
Libguestfs uses an autotools-based build system, with the main files being "configure.ac" and
"Makefile.am". The "generator" subdirectory contains the generator, plus files describing the API. The
"src" subdirectory contains source for the library. The "appliance" and "daemon" subdirectories contain
the source for the code that builds the appliance, and the code that runs in the appliance respectively.
Other directories are covered in the section "SOURCE CODE SUBDIRECTORIES" below.
Apart from the fact that all API entry points go via some generated code, the library is straightforward.
(In fact, even the generated code is designed to be readable, and should be read as ordinary code). Some
actions run entirely in the library, and are written as C functions in files under "src". Others are
forwarded to the daemon where (after some generated RPC marshalling) they appear as C functions in files
under "daemon".
To build from source, first read the "README" file.
"local*" FILES
Files in the top source directory that begin with the prefix "local*" are ignored by git. These files
can contain local configuration or scripts that you need to build libguestfs.
By convention, I have a file called "localconfigure" which is a simple wrapper around "autogen.sh"
containing local configure customizations that I need:
. localenv
./autogen.sh \
--with-default-backend=libvirt \
--enable-gcc-warnings \
--enable-gtk-doc \
-C \
"$@"
So I can use this to build libguestfs:
./localconfigure && make
If there is a file in the top build directory called "localenv", then it will be sourced by "make". This
file can contain any local environment variables needed, eg. for skipping tests:
# Use an alternate python binary.
export PYTHON=python3
# Skip this test, it is broken.
export SKIP_TEST_BTRFS_FSCK=1
Note that "localenv" is included by the top Makefile (so it's a Makefile fragment). But if it is also
sourced by your "localconfigure" script then it is used as a shell script.
ADDING A NEW API ACTION
Because large amounts of boilerplate code in libguestfs are generated, this makes it easy to extend the
libguestfs API.
To add a new API action there are two changes:
1. You need to add a description of the call (name, parameters, return type, tests, documentation) to
"generator/actions.ml".
There are two sorts of API action, depending on whether the call goes through to the daemon in the
appliance, or is serviced entirely by the library (see "ARCHITECTURE" above). "guestfs_sync" is an
example of the former, since the sync is done in the appliance. "guestfs_set_trace" is an example of
the latter, since a trace flag is maintained in the handle and all tracing is done on the library
side.
Most new actions are of the first type, and get added to the "daemon_functions" list. Each function
has a unique procedure number used in the RPC protocol which is assigned to that action when we
publish libguestfs and cannot be reused. Take the latest procedure number and increment it.
For library-only actions of the second type, add to the "non_daemon_functions" list. Since these
functions are serviced by the library and do not travel over the RPC mechanism to the daemon, these
functions do not need a procedure number, and so the procedure number is set to "-1".
2. Implement the action (in C):
For daemon actions, implement the function "do_<name>" in the "daemon/" directory.
For library actions, implement the function "guestfs__<name>" (note: double underscore) in the "src/"
directory.
In either case, use another function as an example of what to do.
After making these changes, use "make" to compile.
Note that you don't need to implement the RPC, language bindings, manual pages or anything else. It's
all automatically generated from the OCaml description.
ADDING TESTS FOR AN API ACTION
You can supply zero or as many tests as you want per API call. The tests can either be added as part of
the API description ("generator/actions.ml"), or in some rarer cases you may want to drop a script into
"tests/*/". Note that adding a script to "tests/*/" is slower, so if possible use the first method.
The following describes the test environment used when you add an API test in "actions.ml".
The test environment has 4 block devices:
"/dev/sda" 500MB
General block device for testing.
"/dev/sdb" 50MB
"/dev/sdb1" is an ext2 filesystem used for testing filesystem write operations.
"/dev/sdc" 10MB
Used in a few tests where two block devices are needed.
"/dev/sdd"
ISO with fixed content (see "images/test.iso").
To be able to run the tests in a reasonable amount of time, the libguestfs appliance and block devices
are reused between tests. So don't try testing "guestfs_kill_subprocess" :-x
Each test starts with an initial scenario, selected using one of the "Init*" expressions, described in
"generator/types.ml". These initialize the disks mentioned above in a particular way as documented in
"types.ml". You should not assume anything about the previous contents of other disks that are not
initialized.
You can add a prerequisite clause to any individual test. This is a run-time check, which, if it fails,
causes the test to be skipped. Useful if testing a command which might not work on all variations of
libguestfs builds. A test that has prerequisite of "Always" means to run unconditionally.
In addition, packagers can skip individual tests by setting environment variables before running "make
check".
SKIP_TEST_<CMD>_<NUM>=1
eg: "SKIP_TEST_COMMAND_3=1" skips test #3 of "guestfs_command".
or:
SKIP_TEST_<CMD>=1
eg: "SKIP_TEST_ZEROFREE=1" skips all "guestfs_zerofree" tests.
Packagers can run only certain tests by setting for example:
TEST_ONLY="vfs_type zerofree"
See "tests/c-api/tests.c" for more details of how these environment variables work.
DEBUGGING NEW API ACTIONS
Test new actions work before submitting them.
You can use guestfish to try out new commands.
Debugging the daemon is a problem because it runs inside a minimal environment. However you can fprintf
messages in the daemon to stderr, and they will show up if you use "guestfish -v".
ADDING A NEW LANGUAGE BINDING
All language bindings must be generated by the generator (see the "generator" subdirectory).
There is no documentation for this yet. We suggest you look at an existing binding, eg.
"generator/ocaml.ml" or "generator/perl.ml".
ADDING TESTS FOR LANGUAGE BINDINGS
Language bindings should come with tests. Previously testing of language bindings was rather ad-hoc, but
we have been trying to formalize the set of tests that every language binding should use.
Currently only the OCaml and Perl bindings actually implement the full set of tests, and the OCaml
bindings are canonical, so you should emulate what the OCaml tests do.
This is the numbering scheme used by the tests:
- 000+ basic tests:
010 load the library
020 create
030 create-flags
040 create multiple handles
050 test setting and getting config properties
060 explicit close
070 optargs
- 100 launch, create partitions and LVs and filesystems
- 400+ events:
410 close event
420 log messages
430 progress messages
- 800+ regression tests (specific to the language)
- 900+ any other custom tests for the language
To save time when running the tests, only 100, 430, 800+, 900+ should launch the handle.
FORMATTING CODE
Our C source code generally adheres to some basic code-formatting conventions. The existing code base is
not totally consistent on this front, but we do prefer that contributed code be formatted similarly. In
short, use spaces-not-TABs for indentation, use 2 spaces for each indentation level, and other than that,
follow the K&R style.
If you use Emacs, add the following to one of one of your start-up files (e.g., ~/.emacs), to help ensure
that you get indentation right:
;;; In libguestfs, indent with spaces everywhere (not TABs).
;;; Exceptions: Makefile and ChangeLog modes.
(add-hook 'find-file-hook
'(lambda () (if (and buffer-file-name
(string-match "/libguestfs\\>"
(buffer-file-name))
(not (string-equal mode-name "Change Log"))
(not (string-equal mode-name "Makefile")))
(setq indent-tabs-mode nil))))
;;; When editing C sources in libguestfs, use this style.
(defun libguestfs-c-mode ()
"C mode with adjusted defaults for use with libguestfs."
(interactive)
(c-set-style "K&R")
(setq c-indent-level 2)
(setq c-basic-offset 2))
(add-hook 'c-mode-hook
'(lambda () (if (string-match "/libguestfs\\>"
(buffer-file-name))
(libguestfs-c-mode))))
TESTING YOUR CHANGES
Enable warnings when compiling (and fix any problems this finds):
./configure --enable-gcc-warnings
Useful targets are:
"make check"
Runs the regular test suite.
This is implemented using the regular automake "TESTS" target. See the automake documentation for
details.
"make syntax-check -j1 -k"
Checks for various syntax and style problems in the code.
"make check-valgrind"
Runs a subset of the test suite under valgrind.
Any "Makefile.am" in the tree that has a "check-valgrind:" target will be run by this rule.
"make check-valgrind-local-guests"
Runs a subset of the test suite under valgrind using locally installed libvirt guests (read-only).
"make check-direct"
Runs all tests using default appliance back-end. This only has any effect if a non-default backend
was selected using "./configure --with-default-backend=..."
"make check-valgrind-direct"
Run a subset of the test suite under valgrind using the default appliance back-end.
"make check-uml"
Runs all tests using the User-Mode Linux backend.
As there is no standard location for the User-Mode Linux kernel, you have to set "LIBGUESTFS_HV" to
point to the kernel image, eg:
make check-uml LIBGUESTFS_HV=~/d/linux-um/vmlinux
"make check-valgrind-uml"
Runs all tests using the User-Mode Linux backend, under valgrind.
As above, you have to set "LIBGUESTFS_HV" to point to the kernel.
"make check-with-upstream-qemu"
Runs all tests using a local qemu binary. It looks for the qemu binary in QEMUDIR (defaults to
"$HOME/d/qemu"), but you can set this to another directory on the command line, eg:
make check-with-upstream-qemu QEMUDIR=/usr/src/qemu
"make check-with-upstream-libvirt"
Runs all tests using a local libvirt. This only has any effect if the libvirt backend was selected
using "./configure --with-default-backend=libvirt"
It looks for libvirt in LIBVIRTDIR (defaults to "$HOME/d/libvirt"), but you can set this to another
directory on the command line, eg:
make check-with-upstream-libvirt LIBVIRTDIR=/usr/src/libvirt
"make check-slow"
Runs some slow/long-running tests which are not run by default.
Any "Makefile.am" in the tree that has a "check-slow:" target will be run by this rule.
"make check-all"
Equivalent to running all "make check*" rules.
"make check-release"
Runs a subset of "make check*" rules that are required to pass before a tarball can be released.
Currently this is:
• check
• check-valgrind
• check-direct
• check-valgrind-direct
• check-uml
• check-valgrind-uml
• check-slow
DAEMON CUSTOM PRINTF FORMATTERS
In the daemon code we have created custom printf formatters %Q and %R, which are used to do shell
quoting.
%Q Simple shell quoted string. Any spaces or other shell characters are escaped for you.
%R Same as %Q except the string is treated as a path which is prefixed by the sysroot.
For example:
asprintf (&cmd, "cat %R", path);
would produce "cat /sysroot/some\ path\ with\ spaces"
Note: Do not use these when you are passing parameters to the "command{,r,v,rv}()" functions. These
parameters do NOT need to be quoted because they are not passed via the shell (instead, straight to
exec). You probably want to use the "sysroot_path()" function however.
SUBMITTING YOUR NEW API ACTIONS
Submit patches to the mailing list: http://www.redhat.com/mailman/listinfo/libguestfs and CC to
rjones@redhat.com.
INTERNATIONALIZATION (I18N) SUPPORT
We support i18n (gettext anyhow) in the library.
However many messages come from the daemon, and we don't translate those at the moment. One reason is
that the appliance generally has all locale files removed from it, because they take up a lot of space.
So we'd have to readd some of those, as well as copying our PO files into the appliance.
Debugging messages are never translated, since they are intended for the programmers.
SOURCE CODE SUBDIRECTORIES
"align"
virt-alignment-scan(1) command and documentation.
"appliance"
The libguestfs appliance, build scripts and so on.
"bash"
Bash tab-completion scripts.
"build-aux"
Various build scripts used by autotools.
"builder"
virt-builder(1) command and documentation.
"cat"
The virt-cat(1), virt-filesystems(1) and virt-ls(1) commands and documentation.
"contrib"
Outside contributions, experimental parts.
"daemon"
The daemon that runs inside the libguestfs appliance and carries out actions.
"df"
virt-df(1) command and documentation.
"edit"
virt-edit(1) command and documentation.
"examples"
C API example code.
"fish"
guestfish(1), the command-line shell, and various shell scripts built on top such as virt-copy-in(1),
virt-copy-out(1), virt-tar-in(1), virt-tar-out(1).
"format"
virt-format(1) command and documentation.
"fuse"
guestmount(1), FUSE (userspace filesystem) built on top of libguestfs.
"generator"
The crucially important generator, used to automatically generate large amounts of boilerplate C code
for things like RPC and bindings.
"gnulib"
Gnulib is used as a portability library. A copy of gnulib is included under here.
"html"
Generated HTML manual pages.
"inspector"
virt-inspector(1), the virtual machine image inspector.
"logo"
Logo used on the website. The fish is called Arthur by the way.
"m4"
M4 macros used by autoconf.
"mllib"
Various libraries and common code used by virt-resize(1) and the other tools which are written in
OCaml.
"po"
Translations of simple gettext strings.
"po-docs"
The build infrastructure and PO files for translations of manpages and POD files. Eventually this
will be combined with the "po" directory, but that is rather complicated.
"rescue"
virt-rescue(1) command and documentation.
"resize"
virt-resize(1) command and documentation.
"sparsify"
virt-sparsify(1) command and documentation.
"src"
Source code to the C library.
"sysprep"
virt-sysprep(1) command and documentation.
"tests"
Tests.
"test-tool"
Test tool for end users to test if their qemu/kernel combination will work with libguestfs.
"tmp"
Used for temporary files when running the tests (instead of "/tmp" etc). The reason is so that you
can run multiple parallel tests of libguestfs without having one set of tests overwriting the
appliance created by another.
"tools"
Command line tools written in Perl (virt-win-reg(1) and many others).
"csharp"
"erlang"
"gobject"
"golang"
"haskell"
"java"
"lua"
"ocaml"
"php"
"perl"
"python"
"ruby"
Language bindings.
MAKING A STABLE RELEASE
When we make a stable release, there are several steps documented here. See "LIBGUESTFS VERSION NUMBERS"
for general information about the stable branch policy.
• Check "make && make check" works on at least Fedora, Debian and Ubuntu.
• Finalize "guestfs-release-notes.pod"
• Update ROADMAP.
• Run "src/api-support/update-from-tarballs.sh".
• Push and pull from Transifex.
Run:
tx push -s
to push the latest POT files to Transifex. Then run:
./tx-pull.sh
which is a wrapper to pull the latest translated "*.po" files.
• Consider updating gnulib to latest upstream version.
• Create new stable and development directories under http://libguestfs.org/download.
• Edit "index.html.in" on website.
• Create the branch in git:
git tag -a 1.XX.0 -m "Version 1.XX.0 (stable)"
git tag -a 1.YY.0 -m "Version 1.YY.0 (development)"
git branch stable-1.XX
git push origin tag 1.XX.0 1.YY.0 stable-1.XX
LIMITS
PROTOCOL LIMITS
Internally libguestfs uses a message-based protocol to pass API calls and their responses to and from a
small "appliance" (see "INTERNALS" for plenty more detail about this). The maximum message size used by
the protocol is slightly less than 4 MB. For some API calls you may need to be aware of this limit. The
API calls which may be affected are individually documented, with a link back to this section of the
documentation.
In libguestfs < 1.19.32, several calls had to encode either their entire argument list or their entire
return value (or sometimes both) in a single protocol message, and this gave them an arbitrary limitation
on how much data they could handle. For example, "guestfs_cat" could only download a file if it was less
than around 4 MB in size. In later versions of libguestfs, some of these limits have been removed. The
APIs which were previously limited but are now unlimited (except perhaps by available memory) are listed
below. To find out if a specific API is subject to protocol limits, check for the warning in the API
documentation which links to this section, and remember to check the version of the documentation that
matches the version of libguestfs you are using.
"guestfs_cat", "guestfs_find", "guestfs_read_file", "guestfs_read_lines", "guestfs_write",
"guestfs_write_append", "guestfs_lstatlist", "guestfs_lxattrlist", "guestfs_readlinklist", "guestfs_ls".
See also "UPLOADING" and "DOWNLOADING" for further information about copying large amounts of data into
or out of a filesystem.
MAXIMUM NUMBER OF DISKS
In libguestfs ≥ 1.19.7, you can query the maximum number of disks that may be added by calling
"guestfs_max_disks". In earlier versions of libguestfs (ie. where this call is not available) you should
assume the maximum is 25.
The rest of this section covers implementation details, which could change in future.
When using virtio-scsi disks (the default if available in qemu) the current limit is 255 disks. When
using virtio-blk (the old default) the limit is around 27 disks, but may vary according to implementation
details and whether the network is enabled.
Virtio-scsi as used by libguestfs is configured to use one target per disk, and 256 targets are
available.
Virtio-blk consumes 1 virtual PCI slot per disk, and PCI is limited to 31 slots, but some of these are
used for other purposes.
One virtual disk is used by libguestfs internally.
Before libguestfs 1.19.7, disk names had to be a single character (eg. "/dev/sda" through "/dev/sdz"),
and since one disk is reserved, that meant the limit was 25. This has been fixed in more recent
versions.
In libguestfs ≥ 1.20 it is possible to hot plug disks. See "HOTPLUGGING".
MAXIMUM NUMBER OF PARTITIONS PER DISK
Virtio limits the maximum number of partitions per disk to 15.
This is because it reserves 4 bits for the minor device number (thus "/dev/vda", and "/dev/vda1" through
"/dev/vda15").
If you attach a disk with more than 15 partitions, the extra partitions are ignored by libguestfs.
MAXIMUM SIZE OF A DISK
Probably the limit is between 2**63-1 and 2**64-1 bytes.
We have tested block devices up to 1 exabyte (2**60 or 1,152,921,504,606,846,976 bytes) using sparse
files backed by an XFS host filesystem.
Although libguestfs probably does not impose any limit, the underlying host storage will. If you store
disk images on a host ext4 filesystem, then the maximum size will be limited by the maximum ext4 file
size (currently 16 TB). If you store disk images as host logical volumes then you are limited by the
maximum size of an LV.
For the hugest disk image files, we recommend using XFS on the host for storage.
MAXIMUM SIZE OF A PARTITION
The MBR (ie. classic MS-DOS) partitioning scheme uses 32 bit sector numbers. Assuming a 512 byte sector
size, this means that MBR cannot address a partition located beyond 2 TB on the disk.
It is recommended that you use GPT partitions on disks which are larger than this size. GPT uses 64 bit
sector numbers and so can address partitions which are theoretically larger than the largest disk we
could support.
MAXIMUM SIZE OF A FILESYSTEM, FILES, DIRECTORIES
This depends on the filesystem type. libguestfs itself does not impose any known limit. Consult
Wikipedia or the filesystem documentation to find out what these limits are.
MAXIMUM UPLOAD AND DOWNLOAD
The API functions "guestfs_upload", "guestfs_download", "guestfs_tar_in", "guestfs_tar_out" and the like
allow unlimited sized uploads and downloads.
INSPECTION LIMITS
The inspection code has several arbitrary limits on things like the size of Windows Registry hive it will
read, and the length of product name. These are intended to stop a malicious guest from consuming
arbitrary amounts of memory and disk space on the host, and should not be reached in practice. See the
source code for more information.
ENVIRONMENT VARIABLES
FEBOOTSTRAP_KERNEL
FEBOOTSTRAP_MODULES
When using supermin ≥ 4.1.0, these have been renamed "SUPERMIN_KERNEL" and "SUPERMIN_MODULES".
LIBGUESTFS_APPEND
Pass additional options to the guest kernel.
LIBGUESTFS_ATTACH_METHOD
This is the old way to set "LIBGUESTFS_BACKEND".
LIBGUESTFS_BACKEND
Choose the default way to create the appliance. See "guestfs_set_backend" and "BACKEND".
LIBGUESTFS_CACHEDIR
The location where libguestfs will cache its appliance, when using a supermin appliance. The
appliance is cached and shared between all handles which have the same effective user ID.
If "LIBGUESTFS_CACHEDIR" is not set, then "TMPDIR" is used. If "TMPDIR" is not set, then "/var/tmp"
is used.
See also "LIBGUESTFS_TMPDIR", "guestfs_set_cachedir".
LIBGUESTFS_DEBUG
Set "LIBGUESTFS_DEBUG=1" to enable verbose messages. This has the same effect as calling
"guestfs_set_verbose (g, 1)".
LIBGUESTFS_HV
Set the default hypervisor (usually qemu) binary that libguestfs uses. If not set, then the qemu
which was found at compile time by the configure script is used.
See also "QEMU WRAPPERS" above.
LIBGUESTFS_MEMSIZE
Set the memory allocated to the qemu process, in megabytes. For example:
LIBGUESTFS_MEMSIZE=700
LIBGUESTFS_PATH
Set the path that libguestfs uses to search for a supermin appliance. See the discussion of paths in
section "PATH" above.
LIBGUESTFS_QEMU
This is the old way to set "LIBGUESTFS_HV".
LIBGUESTFS_TMPDIR
The location where libguestfs will store temporary files used by each handle.
If "LIBGUESTFS_TMPDIR" is not set, then "TMPDIR" is used. If "TMPDIR" is not set, then "/tmp" is
used.
See also "LIBGUESTFS_CACHEDIR", "guestfs_set_tmpdir".
LIBGUESTFS_TRACE
Set "LIBGUESTFS_TRACE=1" to enable command traces. This has the same effect as calling
"guestfs_set_trace (g, 1)".
PATH
Libguestfs may run some external programs, and relies on $PATH being set to a reasonable value. If
using the libvirt backend, libvirt will not work at all unless $PATH contains the path of qemu/KVM.
Note that PHP by default removes $PATH from the environment which tends to break everything.
SUPERMIN_KERNEL
SUPERMIN_MODULES
These two environment variables allow the kernel that libguestfs uses in the appliance to be
selected. If $SUPERMIN_KERNEL is not set, then the most recent host kernel is chosen. For more
information about kernel selection, see supermin-helper(8). This feature is only available in
supermin / febootstrap ≥ 3.8.
TMPDIR
See "LIBGUESTFS_CACHEDIR", "LIBGUESTFS_TMPDIR".
SEE ALSO
guestfs-examples(3), guestfs-erlang(3), guestfs-golang(3), guestfs-java(3), guestfs-lua(3),
guestfs-ocaml(3), guestfs-perl(3), guestfs-python(3), guestfs-ruby(3), guestfish(1), guestmount(1),
virt-alignment-scan(1), virt-builder(1), virt-cat(1), virt-copy-in(1), virt-copy-out(1), virt-df(1),
virt-edit(1), virt-filesystems(1), virt-format(1), virt-inspector(1), virt-list-filesystems(1),
virt-list-partitions(1), virt-ls(1), virt-make-fs(1), virt-rescue(1), virt-resize(1), virt-sparsify(1),
virt-sysprep(1), virt-tar(1), virt-tar-in(1), virt-tar-out(1), virt-win-reg(1), guestfs-faq(1),
guestfs-performance(1), guestfs-release-notes(1), guestfs-testing(1), libguestfs-test-tool(1),
libguestfs-make-fixed-appliance(1), supermin(8), supermin-helper(8), qemu(1), hivex(3), stap(1),
sd-journal(3), http://libguestfs.org/.
Tools with a similar purpose: fdisk(8), parted(8), kpartx(8), lvm(8), disktype(1).
AUTHORS
Richard W.M. Jones ("rjones at redhat dot com")
COPYRIGHT
Copyright (C) 2009-2014 Red Hat Inc.
LICENSE
This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser
General Public License as published by the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
Public License for more details.
You should have received a copy of the GNU Lesser General Public License along with this library; if not,
write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
BUGS
To get a list of bugs against libguestfs, use this link:
https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
To report a new bug against libguestfs, use this link:
https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
When reporting a bug, please supply:
• The version of libguestfs.
• Where you got libguestfs (eg. which Linux distro, compiled from source, etc)
• Describe the bug accurately and give a way to reproduce it.
• Run libguestfs-test-tool(1) and paste the complete, unedited output into the bug report.