SYNOPSIS

DESCRIPTION

fanotify_mark(2)
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
flag
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_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(2),
readdir(2)
(but see BUGS), and
closedir(2)
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.

SEE ALSO

COLOPHON

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