Provided by: libarchive-dev_3.4.0-2ubuntu1.5_amd64 
NAME
archive_entry_acl_add_entry, archive_entry_acl_add_entry_w, archive_entry_acl_clear,
archive_entry_acl_count, archive_entry_acl_from_text, archive_entry_acl_from_text_w,
archive_entry_acl_next, archive_entry_acl_next_w, archive_entry_acl_reset, archive_entry_acl_to_text,
archive_entry_acl_to_text_w, archive_entry_acl_types — functions for manipulating Access Control Lists in
archive entry descriptions
LIBRARY
Streaming Archive Library (libarchive, -larchive)
SYNOPSIS
#include <archive_entry.h>
void
archive_entry_acl_add_entry(struct archive_entry *a, int type, int permset, int tag, int qualifier,
const char *name);
void
archive_entry_acl_add_entry_w(struct archive_entry *a, int type, int permset, int tag, int qualifier,
const wchar_t *name);
void
archive_entry_acl_clear(struct archive_entry *a);
int
archive_entry_acl_count(struct archive_entry *a, int type);
int
archive_entry_acl_from_text(struct archive_entry *a, const char *text, int type);
int
archive_entry_acl_from_text_w(struct archive_entry *a, const wchar_t *text, int type);
int
archive_entry_acl_next(struct archive_entry *a, int type, int *ret_type, int *ret_permset, int *ret_tag,
int *ret_qual, const char **ret_name);
int
archive_entry_acl_next_w(struct archive_entry *a, int type, int *ret_type, int *ret_permset,
int *ret_tag, int *ret_qual, const wchar_t **ret_name);
int
archive_entry_acl_reset(struct archive_entry *a, int type);
char *
archive_entry_acl_to_text(struct archive_entry *a, ssize_t *len_p, int flags);
wchar_t *
archive_entry_acl_to_text_w(struct archive_entry *a, ssize_t *len_p, int flags);
int
archive_entry_acl_types(struct archive_entry *a);
DESCRIPTION
The “Access Control Lists (ACLs)” extend the standard Unix permission model. The ACL interface of
libarchive supports both POSIX.1e and NFSv4 style ACLs. Use of ACLs is restricted by various levels of
ACL support in operating systems, file systems and archive formats.
POSIX.1e Access Control Lists
A POSIX.1e ACL consists of a number of independent entries. Each entry specifies the permission set as a
bitmask of basic permissions. Valid permissions in the permset are:
ARCHIVE_ENTRY_ACL_READ (r)
ARCHIVE_ENTRY_ACL_WRITE (w)
ARCHIVE_ENTRY_ACL_EXECUTE (x)
The permissions correspond to the normal Unix permissions.
The tag specifies the principal to which the permission applies. Valid values are:
ARCHIVE_ENTRY_ACL_USER The user specified by the name field.
ARCHIVE_ENTRY_ACL_USER_OBJ The owner of the file.
ARCHIVE_ENTRY_ACL_GROUP The group specified by the name field.
ARCHIVE_ENTRY_ACL_GROUP_OBJ The group which owns the file.
ARCHIVE_ENTRY_ACL_MASK The maximum permissions to be obtained via group permissions.
ARCHIVE_ENTRY_ACL_OTHER Any principal who is not the file owner or a member of the owning
group.
The principals ARCHIVE_ENTRY_ACL_USER_OBJ, ARCHIVE_ENTRY_ACL_GROUP_OBJ and ARCHIVE_ENTRY_ACL_OTHER are
equivalent to user, group and other in the classic Unix permission model and specify non-extended ACL
entries.
All files have an access ACL (ARCHIVE_ENTRY_ACL_TYPE_ACCESS). This specifies the permissions required
for access to the file itself. Directories have an additional ACL (ARCHIVE_ENTRY_ACL_TYPE_DEFAULT),
which controls the initial access ACL for newly-created directory entries.
NFSv4 Access Control Lists
A NFSv4 ACL consists of multiple individual entries called Access Control Entries (ACEs).
There are four possible types of a NFSv4 ACE:
ARCHIVE_ENTRY_ACL_TYPE_ALLOW Allow principal to perform actions requiring given permissions.
ARCHIVE_ENTRY_ACL_TYPE_DENY Prevent principal from performing actions requiring given permissions.
ARCHIVE_ENTRY_ACL_TYPE_AUDIT Log access attempts by principal which require given permissions.
ARCHIVE_ENTRY_ACL_TYPE_ALARM Trigger a system alarm on access attempts by principal which require
given permissions.
The tag specifies the principal to which the permission applies. Valid values are:
ARCHIVE_ENTRY_ACL_USER The user specified by the name field.
ARCHIVE_ENTRY_ACL_USER_OBJ The owner of the file.
ARCHIVE_ENTRY_ACL_GROUP The group specified by the name field.
ARCHIVE_ENTRY_ACL_GROUP_OBJ The group which owns the file.
ARCHIVE_ENTRY_ACL_EVERYONE Any principal who is not the file owner or a member of the owning
group.
Entries with the ARCHIVE_ENTRY_ACL_USER or ARCHIVE_ENTRY_ACL_GROUP tag store the user and group name in
the name string and optionally the user or group ID in the qualifier integer.
NFSv4 ACE permissions and flags are stored in the same permset bitfield. Some permissions share the same
constant and permission character but have different effect on directories than on files. The following
ACE permissions are supported:
ARCHIVE_ENTRY_ACL_READ_DATA (r)
Read data (file).
ARCHIVE_ENTRY_ACL_LIST_DIRECTORY (r)
List entries (directory).
ARCHIVE_ENTRY_ACL_WRITE_DATA (w)
Write data (file).
ARCHIVE_ENTRY_ACL_ADD_FILE (w)
Create files (directory).
ARCHIVE_ENTRY_ACL_EXECUTE (x)
Execute file or change into a directory.
ARCHIVE_ENTRY_ACL_APPEND_DATA (p)
Append data (file).
ARCHIVE_ENTRY_ACL_ADD_SUBDIRECTORY (p)
Create subdirectories (directory).
ARCHIVE_ENTRY_ACL_DELETE_CHILD (D)
Remove files and subdirectories inside a directory.
ARCHIVE_ENTRY_ACL_DELETE (d)
Remove file or directory.
ARCHIVE_ENTRY_ACL_READ_ATTRIBUTES (a)
Read file or directory attributes.
ARCHIVE_ENTRY_ACL_WRITE_ATTRIBUTES (A)
Write file or directory attributes.
ARCHIVE_ENTRY_ACL_READ_NAMED_ATTRS (R)
Read named file or directory attributes.
ARCHIVE_ENTRY_ACL_WRITE_NAMED_ATTRS (W)
Write named file or directory attributes.
ARCHIVE_ENTRY_ACL_READ_ACL (c)
Read file or directory ACL.
ARCHIVE_ENTRY_ACL_WRITE_ACL (C)
Write file or directory ACL.
ARCHIVE_ENTRY_ACL_WRITE_OWNER (o)
Change owner of a file or directory.
ARCHIVE_ENTRY_ACL_SYNCHRONIZE (s)
Use synchronous I/O.
The following NFSv4 ACL inheritance flags are supported:
ARCHIVE_ENTRY_ACL_ENTRY_FILE_INHERIT (f)
Inherit parent directory ACE to files.
ARCHIVE_ENTRY_ACL_ENTRY_DIRECTORY_INHERIT (d)
Inherit parent directory ACE to subdirectories.
ARCHIVE_ENTRY_ACL_ENTRY_INHERIT_ONLY (i)
Only inherit, do not apply the permission on the directory itself.
ARCHIVE_ENTRY_ACL_ENTRY_NO_PROPAGATE_INHERIT (n)
Do not propagate inherit flags. Only first-level entries inherit ACLs.
ARCHIVE_ENTRY_ACL_ENTRY_SUCCESSFUL_ACCESS (S)
Trigger alarm or audit on successful access.
ARCHIVE_ENTRY_ACL_ENTRY_FAILED_ACCESS (F)
Trigger alarm or audit on failed access.
ARCHIVE_ENTRY_ACL_ENTRY_INHERITED (I)
Mark that ACE was inherited.
Functions
archive_entry_acl_add_entry() and archive_entry_acl_add_entry_w() add a single ACL entry. For the access
ACL and non-extended principals, the classic Unix permissions are updated. An archive entry cannot
contain both POSIX.1e and NFSv4 ACL entries.
archive_entry_acl_clear() removes all ACL entries and resets the enumeration pointer.
archive_entry_acl_count() counts the ACL entries that have the given type mask. type can be the bitwise-
or of
ARCHIVE_ENTRY_ACL_TYPE_ACCESS
ARCHIVE_ENTRY_ACL_TYPE_DEFAULT
for POSIX.1e ACLs and
ARCHIVE_ENTRY_ACL_TYPE_ALLOW
ARCHIVE_ENTRY_ACL_TYPE_DENY
ARCHIVE_ENTRY_ACL_TYPE_AUDIT
ARCHIVE_ENTRY_ACL_TYPE_ALARM
for NFSv4 ACLs. For POSIX.1e ACLs if ARCHIVE_ENTRY_ACL_TYPE_ACCESS is included and at least one extended
ACL entry is found, the three non-extended ACLs are added.
archive_entry_acl_from_text() and archive_entry_acl_from_text_w() add new (or merge with existing) ACL
entries from (wide) text. The argument type may take one of the following values:
ARCHIVE_ENTRY_ACL_TYPE_ACCESS
ARCHIVE_ENTRY_ACL_TYPE_DEFAULT
ARCHIVE_ENTRY_ACL_TYPE_NFS4
Supports all formats that can be created with archive_entry_acl_to_text() or respectively
archive_entry_acl_to_text_w(). Existing ACL entries are preserved. To get a clean new ACL from text
archive_entry_acl_clear() must be called first. Entries prefixed with “default:” are treated as
ARCHIVE_ENTRY_ACL_TYPE_DEFAULT unless type is ARCHIVE_ENTRY_ACL_TYPE_NFS4. Invalid entries, non-
parseable ACL entries and entries beginning with the ‘#’ character (comments) are skipped.
archive_entry_acl_next() and archive_entry_acl_next_w() return the next entry of the ACL list. This
functions may only be called after archive_entry_acl_reset() has indicated the presence of extended ACL
entries.
archive_entry_acl_reset() prepare reading the list of ACL entries with archive_entry_acl_next() or
archive_entry_acl_next_w(). The function returns 0 if no non-extended ACLs are found. In this case, the
access permissions should be obtained by archive_entry_mode(3) or set using chmod(2). Otherwise, the
function returns the same value as archive_entry_acl_count().
archive_entry_acl_to_text() and archive_entry_acl_to_text_w() convert the ACL entries for the given type
into a (wide) string of ACL entries separated by newline. If the pointer len_p is not NULL, then the
function shall return the length of the string (not including the NULL terminator) in the location
pointed to by len_p. The flag argument is a bitwise-or.
The following flags are effective only on POSIX.1e ACL:
ARCHIVE_ENTRY_ACL_TYPE_ACCESS
Output access ACLs.
ARCHIVE_ENTRY_ACL_TYPE_DEFAULT
Output POSIX.1e default ACLs.
ARCHIVE_ENTRY_ACL_STYLE_MARK_DEFAULT
Prefix each default ACL entry with the word “default:”.
ARCHIVE_ENTRY_ACL_STYLE_SOLARIS
The mask and other ACLs don not contain a double colon.
The following flags are effecive only on NFSv4 ACL:
ARCHIVE_ENTRY_ACL_STYLE_COMPACT
Do not output minus characters for unset permissions and flags in NFSv4 ACL permission and
flag fields.
The following flags are effective on both POSIX.1e and NFSv4 ACL:
ARCHIVE_ENTRY_ACL_STYLE_EXTRA_ID
Add an additional colon-separated field containing the user or group id.
ARCHIVE_ENTRY_ACL_STYLE_SEPARATOR_COMMA
Separate ACL entries with comma instead of newline.
If the archive entry contains NFSv4 ACLs, all types of NFSv4 ACLs are returned. It the entry contains
POSIX.1e ACLs and none of the flags ARCHIVE_ENTRY_ACL_TYPE_ACCESS or ARCHIVE_ENTRY_ACL_TYPE_DEFAULT are
specified, both access and default entries are returned and default entries are prefixed with “default:”.
archive_entry_acl_types() get ACL entry types contained in an archive entry's ACL. As POSIX.1e and NFSv4
ACL entries cannot be mixed, this function is a very efficient way to detect if an ACL already contains
POSIX.1e or NFSv4 ACL entries.
RETURN VALUES
archive_entry_acl_count() and archive_entry_acl_reset() returns the number of ACL entries that match the
given type mask. For POSIX.1e ACLS if the type mask includes ARCHIVE_ENTRY_ACL_TYPE_ACCESS and at least
one extended ACL entry exists, the three classic Unix permissions are counted.
archive_entry_acl_from_text() and archive_entry_acl_from_text_w() return ARCHIVE_OK if all entries were
successfully parsed and ARCHIVE_WARN if one or more entries were invalid or non-parseable.
archive_entry_acl_next() and archive_entry_acl_next_w() return ARCHIVE_OK on success, ARCHIVE_EOF if no
more ACL entries exist and ARCHIVE_WARN if archive_entry_acl_reset() has not been called first.
archive_entry_acl_to_text() returns a string representing the ACL entries matching the given type and
flags on success or NULL on error.
archive_entry_acl_to_text_w() returns a wide string representing the ACL entries matching the given type
and flags on success or NULL on error.
archive_entry_acl_types() returns a bitmask of ACL entry types or 0 if archive entry has no ACL entries.
SEE ALSO
archive_entry(3), libarchive(3)
Debian February 15, 2017 ARCHIVE_ENTRY_ACL(3)