bionic (2) fanotify_mark.2.gz

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NAME

       fanotify_mark - add, remove, or modify an fanotify mark on a filesystem object

SYNOPSIS

       #include <sys/fanotify.h>

       int fanotify_mark(int fanotify_fd, unsigned int flags,
                         uint64_t mask, int dirfd, const char *pathname);

DESCRIPTION

       For an overview of the fanotify API, see fanotify(7).

       fanotify_mark() adds, removes, or modifies an fanotify mark on a filesystem object.  The caller must have
       read permission on the filesystem object that is to be marked.

       The fanotify_fd argument is a file descriptor returned by fanotify_init(2).

       flags is a bit mask describing the modification to perform.  It must include exactly one of the following
       values:

       FAN_MARK_ADD
              The  events in mask will be added to the mark mask (or to the ignore mask).  mask must be nonempty
              or the error EINVAL will occur.

       FAN_MARK_REMOVE
              The events in argument mask will be removed from the mark mask (or from the  ignore  mask).   mask
              must be nonempty or the error EINVAL will occur.

       FAN_MARK_FLUSH
              Remove  either  all  mount  or  all  non-mount  marks  from the fanotify group.  If flags contains
              FAN_MARK_MOUNT, all marks for mounts are  removed  from  the  group.   Otherwise,  all  marks  for
              directories  and  files are removed.  No flag other than FAN_MARK_MOUNT can be used in conjunction
              with FAN_MARK_FLUSH.  mask is ignored.

       If none of the values above is specified, or more than one is specified, the call fails  with  the  error
       EINVAL.

       In addition, zero or more of the following values may be ORed into flags:

       FAN_MARK_DONT_FOLLOW
              If  pathname  is  a  symbolic link, mark the link itself, rather than the file to which it refers.
              (By default, fanotify_mark() dereferences pathname if it is a symbolic link.)

       FAN_MARK_ONLYDIR
              If the filesystem object to be marked is not a directory, the error ENOTDIR shall be raised.

       FAN_MARK_MOUNT
              Mark the mount point specified by pathname.  If pathname is not itself a mount  point,  the  mount
              point  containing  pathname  will  be  marked.  All directories, subdirectories, and the contained
              files of the mount point will be monitored.

       FAN_MARK_IGNORED_MASK
              The events in mask shall be added to or removed from the ignore mask.

       FAN_MARK_IGNORED_SURV_MODIFY
              The ignore mask shall survive modify events.  If this flag is not set, the ignore mask is  cleared
              when a modify event occurs for the ignored file or directory.

       mask  defines  which events shall be listened for (or which shall be ignored).  It is a bit mask composed
       of the following values:

       FAN_ACCESS
              Create an event when a file or directory (but see BUGS) is accessed (read).

       FAN_MODIFY
              Create an event when a file is modified (write).

       FAN_CLOSE_WRITE
              Create an event when a writable file is closed.

       FAN_CLOSE_NOWRITE
              Create an event when a read-only file or directory is closed.

       FAN_OPEN
              Create an event when a file or directory is opened.

       FAN_Q_OVERFLOW
              Create an event when an overflow of the event queue occurs.   The  size  of  the  event  queue  is
              limited to 16384 entries if FAN_UNLIMITED_QUEUE is not set in fanotify_init(2).

       FAN_OPEN_PERM
              Create  an  event  when  a  permission to open a file or directory is requested.  An fanotify file
              descriptor created with FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required.

       FAN_ACCESS_PERM
              Create an event when a permission to read a file or directory  is  requested.   An  fanotify  file
              descriptor created with FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required.

       FAN_ONDIR
              Create  events  for  directories—for  example,  when  opendir(3),  readdir(3)  (but see BUGS), and
              closedir(3) are called.  Without this flag, only events for files are created.

       FAN_EVENT_ON_CHILD
              Events for the immediate children of marked directories shall be created.  The flag has no  effect
              when  marking  mounts.   Note  that events are not generated for children of the subdirectories of
              marked directories.  To monitor complete directory trees it is  necessary  to  mark  the  relevant
              mount.

       The following composed value is defined:

       FAN_CLOSE
              A file is closed (FAN_CLOSE_WRITE|FAN_CLOSE_NOWRITE).

       The  filesystem object to be marked is determined by the file descriptor dirfd and the pathname specified
       in pathname:

       *  If pathname is NULL, dirfd defines the filesystem object to be marked.

       *  If pathname is NULL, and dirfd takes the special value AT_FDCWD, the current working directory  is  to
          be marked.

       *  If pathname is absolute, it defines the filesystem object to be marked, and dirfd is ignored.

       *  If  pathname is relative, and dirfd does not have the value AT_FDCWD, then the filesystem object to be
          marked is determined by interpreting pathname relative the directory referred to by dirfd.

       *  If pathname is relative, and dirfd has the value AT_FDCWD, then the filesystem object to be marked  is
          determined by interpreting pathname relative the current working directory.

RETURN VALUE

       On success, fanotify_mark() returns 0.  On error, -1 is returned, and errno is set to indicate the error.

ERRORS

       EBADF  An invalid file descriptor was passed in fanotify_fd.

       EINVAL An invalid value was passed in flags or mask, or fanotify_fd was not an fanotify file descriptor.

       EINVAL The  fanotify  file  descriptor  was  opened  with  FAN_CLASS_NOTIF  and  mask contains a flag for
              permission events (FAN_OPEN_PERM or FAN_ACCESS_PERM).

       ENOENT The filesystem object indicated by dirfd and pathname does not exist.  This error also occurs when
              trying to remove a mark from an object which is not marked.

       ENOMEM The necessary memory could not be allocated.

       ENOSPC The  number  of marks exceeds the limit of 8192 and the FAN_UNLIMITED_MARKS flag was not specified
              when the fanotify file descriptor was created with fanotify_init(2).

       ENOSYS This kernel does not implement fanotify_mark().  The fanotify API is available only if the  kernel
              was configured with CONFIG_FANOTIFY.

       ENOTDIR
              flags contains FAN_MARK_ONLYDIR, and dirfd and pathname do not specify a directory.

VERSIONS

       fanotify_mark() was introduced in version 2.6.36 of the Linux kernel and enabled in version 2.6.37.

CONFORMING TO

       This system call is Linux-specific.

BUGS

       The following bugs were present in Linux kernels before version 3.16:

       *  If  flags  contains  FAN_MARK_FLUSH,  dirfd  and pathname must specify a valid filesystem object, even
          though this object is not used.

       *  readdir(2) does not generate a FAN_ACCESS event.

       *  If fanotify_mark() is called with FAN_MARK_FLUSH, flags is not checked for invalid values.

SEE ALSO

       fanotify_init(2), fanotify(7)

COLOPHON

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