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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | NOTES | BUGS | SEE ALSO | COLOPHON |
FANOTIFY_MARK(2) Linux Programmer's Manual FANOTIFY_MARK(2)
fanotify_mark - add, remove, or modify an fanotify mark on a filesys‐
tem object
#include <sys/fanotify.h>
int fanotify_mark(int fanotify_fd, unsigned int flags,
uint64_t mask, int dirfd, const char *pathname);
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 marks for filesystems, all marks for mounts,
or all marks for directories and files from the fanotify
group. If flags contains FAN_MARK_MOUNT, all marks for mounts
are removed from the group. If flags contains
FAN_MARK_FILESYSTEM, all marks for filesystems are removed
from the group. Otherwise, all marks for directories and
files are removed. No flag other than and at most one of the
flags FAN_MARK_MOUNT or FAN_MARK_FILESYSTEM 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. The
events which require the fanotify_fd file descriptor to have
been initialized with the flag FAN_REPORT_FID, such as
FAN_CREATE, FAN_ATTRIB, FAN_MOVE, and FAN_DELETE_SELF, cannot
be provided as a mask when flags contains FAN_MARK_MOUNT.
Attempting to do so will result in the error EINVAL being
returned.
FAN_MARK_FILESYSTEM (since Linux 4.20)
Mark the filesystem specified by pathname. The filesystem
containing pathname will be marked. All the contained files
and directories of the filesystem from any 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_EXEC (since Linux 5.0)
Create an event when a file is opened with the intent to be
executed. See NOTES for additional details.
FAN_ATTRIB (since Linux 5.1)
Create an event when the metadata for a file or directory has
changed. An fanotify file descriptor created with
FAN_REPORT_FID is required.
FAN_CREATE (since Linux 5.1)
Create an event when a file or directory has been created in a
marked parent directory. An fanotify file descriptor created
with FAN_REPORT_FID is required.
FAN_DELETE (since Linux 5.1)
Create an event when a file or directory has been deleted in a
marked parent directory. An fanotify file descriptor created
with FAN_REPORT_FID is required.
FAN_DELETE_SELF (since Linux 5.1)
Create an event when a marked file or directory itself is
deleted. An fanotify file descriptor created with
FAN_REPORT_FID is required.
FAN_MOVED_FROM (since Linux 5.1)
Create an event when a file or directory has been moved from a
marked parent directory. An fanotify file descriptor created
with FAN_REPORT_FID is required.
FAN_MOVED_TO (since Linux 5.1)
Create an event when a file or directory has been moved to a
marked parent directory. An fanotify file descriptor created
with FAN_REPORT_FID is required.
FAN_MOVE_SELF (since Linux 5.1)
Create an event when a marked file or directory itself has
been moved. An fanotify file descriptor created with
FAN_REPORT_FID is required.
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_OPEN_EXEC_PERM (since Linux 5.0)
Create an event when a permission to open a file for execution
is requested. An fanotify file descriptor created with
FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required. See
NOTES for additional details.
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, events are created only for files. In the
context of directory entry events, such as FAN_CREATE,
FAN_DELETE, FAN_MOVED_FROM, and FAN_MOVED_TO, specifying the
flag FAN_ONDIR is required in order to create events when
subdirectory entries are modified (i.e., mkdir(2)/ rmdir(2)).
FAN_EVENT_ON_CHILD
Events for the immediate children of marked directories shall
be created. The flag has no effect when marking mounts and
filesystems. Note that events are not generated for children
of the subdirectories of marked directories. More
specifically, the directory entry modification events
FAN_CREATE, FAN_DELETE, FAN_MOVED_FROM, and FAN_MOVED_TO are
not generated for any entry modifications performed inside
subdirectories of marked directories. Note that the events
FAN_DELETE_SELF and FAN_MOVE_SELF are not generated for
children of marked directories. To monitor complete directory
trees it is necessary to mark the relevant mount or
filesystem.
The following composed values are defined:
FAN_CLOSE
A file is closed (FAN_CLOSE_WRITE|FAN_CLOSE_NOWRITE).
FAN_MOVE
A file or directory has been moved
(FAN_MOVED_FROM|FAN_MOVED_TO).
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.
On success, fanotify_mark() returns 0. On error, -1 is returned, and
errno is set to indicate the error.
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
or FAN_REPORT_FID and mask contains a flag for permission
events (FAN_OPEN_PERM or FAN_ACCESS_PERM).
ENODEV The filesystem object indicated by pathname is not associated
with a filesystem that supports fsid (e.g., tmpfs(5)). This
error can be returned only when an fanotify file descriptor
returned by fanotify_init(2) has been created with
FAN_REPORT_FID.
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.
EOPNOTSUPP
The object indicated by pathname is associated with a
filesystem that does not support the encoding of file handles.
This error can be returned only when an fanotify file
descriptor returned by fanotify_init(2) has been created with
FAN_REPORT_FID.
EXDEV The filesystem object indicated by pathname resides within a
filesystem subvolume (e.g., btrfs(5)) which uses a different
fsid than its root superblock. This error can be returned
only when an fanotify file descriptor returned by
fanotify_init(2) has been created with FAN_REPORT_FID.
fanotify_mark() was introduced in version 2.6.36 of the Linux kernel
and enabled in version 2.6.37.
This system call is Linux-specific.
FAN_OPEN_EXEC and FAN_OPEN_EXEC_PERM
When using either FAN_OPEN_EXEC or FAN_OPEN_EXEC_PERM within the
mask, events of these types will be returned only when the direct
execution of a program occurs. More specifically, this means that
events of these types will be generated for files that are opened
using execve(2), execveat(2), or uselib(2). Events of these types
will not be raised in the situation where an interpreter is passed
(or reads) a file for interpretation.
Additionally, if a mark has also been placed on the Linux dynamic
linker, a user should also expect to receive an event for it when an
ELF object has been successfully opened using execve(2) or
execveat(2).
For example, if the following ELF binary were to be invoked and a
FAN_OPEN_EXEC mark has been placed on /:
$ /bin/echo foo
The listening application in this case would receive FAN_OPEN_EXEC
events for both the ELF binary and interpreter, respectively:
/bin/echo
/lib64/ld-linux-x86-64.so.2
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.
fanotify_init(2), fanotify(7)
This page is part of release 5.08 of the Linux man-pages project. A
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latest version of this page, can be found at
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Linux 2020-06-09 FANOTIFY_MARK(2)
Pages that refer to this page: creat(2) , fanotify_init(2) , open(2) , openat(2) , syscalls(2) , proc(5) , procfs(5) , fanotify(7)
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