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.TH FANOTIFY_MARK 2 2016-10-08 "Linux" "Linux Programmer's Manual"

.SH NAME

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

object

.SH SYNOPSIS

.nf

.B #include <sys/fanotify.h>

.PP

.BI "int fanotify_mark(int " fanotify_fd ", unsigned int " flags ,

.BI "                  uint64_t " mask ", int " dirfd \

", const char *" pathname );

.fi

.SH DESCRIPTION

For an overview of the fanotify API, see

.BR fanotify (7).

.PP

.BR 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.

.PP

The

.I fanotify_fd

argument is a file descriptor returned by

.BR fanotify_init (2).

.PP

.I flags

is a bit mask describing the modification to perform.

It must include exactly one of the following values:

.TP

.B FAN_MARK_ADD

The events in

.I mask

will be added to the mark mask (or to the ignore mask).

.I mask

must be nonempty or the error

.B EINVAL

will occur.

.TP

.B FAN_MARK_REMOVE

The events in argument

.I mask

will be removed from the mark mask (or from the ignore mask).

.I mask

must be nonempty or the error

.B EINVAL

will occur.

.TP

.B FAN_MARK_FLUSH

Remove either all mount or all non-mount marks from the fanotify group.

If

.I flags

contains

.BR 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

.B FAN_MARK_MOUNT

can be used in conjunction with

.BR FAN_MARK_FLUSH .

.I mask

is ignored.

.PP

If none of the values above is specified, or more than one is specified,

the call fails with the error

.BR EINVAL .

.PP

In addition,

zero or more of the following values may be ORed into

.IR flags :

.TP

.B FAN_MARK_DONT_FOLLOW

If

.I pathname

is a symbolic link, mark the link itself, rather than the file to which it

refers.

(By default,

.BR fanotify_mark ()

dereferences

.I pathname

if it is a symbolic link.)

.TP

.B FAN_MARK_ONLYDIR

If the filesystem object to be marked is not a directory, the error

.B ENOTDIR

shall be raised.

.TP

.B FAN_MARK_MOUNT

Mark the mount point specified by

.IR pathname .

If

.I pathname

is not itself a mount point, the mount point containing

.I pathname

will be marked.

All directories, subdirectories, and the contained files of the mount point

will be monitored.

.TP

.B FAN_MARK_IGNORED_MASK

The events in

.I mask

shall be added to or removed from the ignore mask.

.TP

.B 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.

.PP

.I mask

defines which events shall be listened for (or which shall be ignored).

It is a bit mask composed of the following values:

.TP

.B FAN_ACCESS

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

.TP

.B FAN_MODIFY

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

.TP

.B FAN_CLOSE_WRITE

Create an event when a writable file is closed.

.TP

.B FAN_CLOSE_NOWRITE

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

.TP

.B FAN_OPEN

Create an event when a file or directory is opened.

.TP

.B 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

.B FAN_UNLIMITED_QUEUE

is not set in

.BR fanotify_init (2).

.TP

.B FAN_OPEN_PERM

Create an event when a permission to open a file or directory is requested.

An fanotify file descriptor created with

.B FAN_CLASS_PRE_CONTENT

or

.B FAN_CLASS_CONTENT

is required.

.TP

.B FAN_ACCESS_PERM

Create an event when a permission to read a file or directory is requested.

An fanotify file descriptor created with

.B FAN_CLASS_PRE_CONTENT

or

.B FAN_CLASS_CONTENT

is required.

.TP

.B FAN_ONDIR

Create events for directories\(emfor example, when

.BR opendir (3),

.BR readdir (3)

(but see BUGS), and

.BR closedir (3)

are called.

Without this flag, only events for files are created.

.TP

.B 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.

.PP

The following composed value is defined:

.TP

.B FAN_CLOSE

A file is closed

.RB ( FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE ).

.PP

The filesystem object to be marked is determined by the file descriptor

.I dirfd

and the pathname specified in

.IR pathname :

.IP * 3

If

.I pathname

is NULL,

.I dirfd

defines the filesystem object to be marked.

.IP *

If

.I pathname

is NULL, and

.I dirfd

takes the special value

.BR AT_FDCWD ,

the current working directory is to be marked.

.IP *

If

.I pathname

is absolute, it defines the filesystem object to be marked, and

.I dirfd

is ignored.

.IP *

If

.I pathname

is relative, and

.I dirfd

does not have the value

.BR AT_FDCWD ,

then the filesystem object to be marked is determined by interpreting

.I pathname

relative the directory referred to by

.IR dirfd .

.IP *

If

.I pathname

is relative, and

.I dirfd

has the value

.BR AT_FDCWD ,

then the filesystem object to be marked is determined by interpreting

.I pathname

relative the current working directory.

.SH RETURN VALUE

On success,

.BR fanotify_mark ()

returns 0.

On error, \-1 is returned, and

.I errno

is set to indicate the error.

.SH ERRORS

.TP

.B EBADF

An invalid file descriptor was passed in

.IR fanotify_fd .

.TP

.B EINVAL

An invalid value was passed in

.IR flags

or

.IR mask ,

or

.I fanotify_fd

was not an fanotify file descriptor.

.TP

.B EINVAL

The fanotify file descriptor was opened with

.B FAN_CLASS_NOTIF

and mask contains a flag for permission events

.RB ( FAN_OPEN_PERM

or

.BR FAN_ACCESS_PERM ).

.TP

.B ENOENT

The filesystem object indicated by

.IR dirfd

and

.IR pathname

does not exist.

This error also occurs when trying to remove a mark from an object

which is not marked.

.TP

.B ENOMEM

The necessary memory could not be allocated.

.TP

.B ENOSPC

The number of marks exceeds the limit of 8192 and the

.B FAN_UNLIMITED_MARKS

flag was not specified when the fanotify file descriptor was created with

.BR fanotify_init (2).

.TP

.B ENOSYS

This kernel does not implement

.BR fanotify_mark ().

The fanotify API is available only if the kernel was configured with

.BR CONFIG_FANOTIFY .

.TP

.B ENOTDIR

.I flags

contains

.BR FAN_MARK_ONLYDIR ,

and

.I dirfd

and

.I pathname

do not specify a directory.

.SH VERSIONS

.BR fanotify_mark ()

was introduced in version 2.6.36 of the Linux kernel and enabled in version

2.6.37.

.SH CONFORMING TO

This system call is Linux-specific.

.SH BUGS

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

.IP * 3

.\" Fixed by commit 0a8dd2db579f7a0ac7033d6b857c3d5dbaa77563

If

.I flags

contains

.BR FAN_MARK_FLUSH ,

.I dirfd

and

.I pathname

must specify a valid filesystem object, even though this object is not used.

.IP *

.\" Fixed by commit d4c7cf6cffb1bc711a833b5e304ba5bcfe76398b

.BR readdir (2)

does not generate a

.B FAN_ACCESS

event.

.IP *

.\" Fixed by commit cc299a98eb13a9853675a9cbb90b30b4011e1406

If

.BR fanotify_mark ()

is called with

.BR FAN_MARK_FLUSH ,

.I flags

is not checked for invalid values.

.SH SEE ALSO

.BR fanotify_init (2),

.BR fanotify (7)

.SH COLOPHON

This page is part of release 4.15 of the Linux

.I man-pages

project.

A description of the project,

information about reporting bugs,

and the latest version of this page,

can be found at

\%https://www.kernel.org/doc/man\-pages/.