fanotify - monitoring filesystem events
The fanotify API provides notification and interception of filesystem events.
Use cases include virus scanning and hierarchical storage management.
Currently, only a limited set of events is supported. In particular, there is
no support for create, delete, and move events. (See
inotify(7) for
details of an API that does notify those events.)
Additional capabilities compared to the
inotify(7) API include the
ability to monitor all of the objects in a mounted filesystem, the ability to
make access permission decisions, and the possibility to read or modify files
before access by other applications.
The following system calls are used with this API:
fanotify_init(2),
fanotify_mark(2),
read(2),
write(2), and
close(2).
The
fanotify_init(2) system call creates and initializes an fanotify
notification group and returns a file descriptor referring to it.
An fanotify notification group is a kernel-internal object that holds a list of
files, directories, filesystems, and mount points for which events shall be
created.
For each entry in an fanotify notification group, two bit masks exist: the
mark mask and the
ignore mask. The mark mask defines file
activities for which an event shall be created. The ignore mask defines
activities for which no event shall be generated. Having these two types of
masks permits a filesystem, mount point, or directory to be marked for
receiving events, while at the same time ignoring events for specific objects
under a mount point or directory.
The
fanotify_mark(2) system call adds a file, directory, filesystem or
mount point to a notification group and specifies which events shall be
reported (or ignored), or removes or modifies such an entry.
A possible usage of the ignore mask is for a file cache. Events of interest for
a file cache are modification of a file and closing of the same. Hence, the
cached directory or mount point is to be marked to receive these events. After
receiving the first event informing that a file has been modified, the
corresponding cache entry will be invalidated. No further modification events
for this file are of interest until the file is closed. Hence, the modify
event can be added to the ignore mask. Upon receiving the close event, the
modify event can be removed from the ignore mask and the file cache entry can
be updated.
The entries in the fanotify notification groups refer to files and directories
via their inode number and to mounts via their mount ID. If files or
directories are renamed or moved within the same mount, the respective entries
survive. If files or directories are deleted or moved to another mount or if
filesystems or mounts are unmounted, the corresponding entries are deleted.
As events occur on the filesystem objects monitored by a notification group, the
fanotify system generates events that are collected in a queue. These events
can then be read (using
read(2) or similar) from the fanotify file
descriptor returned by
fanotify_init(2).
Two types of events are generated:
notification events and
permission events. Notification events are merely informative and
require no action to be taken by the receiving application with the exception
being that the file descriptor provided within a generic event must be closed.
The closing of file descriptors for each event applies only to applications
that have initialized fanotify without using
FAN_REPORT_FID (see
below). Permission events are requests to the receiving application to decide
whether permission for a file access shall be granted. For these events, the
recipient must write a response which decides whether access is granted or
not.
An event is removed from the event queue of the fanotify group when it has been
read. Permission events that have been read are kept in an internal list of
the fanotify group until either a permission decision has been taken by
writing to the fanotify file descriptor or the fanotify file descriptor is
closed.
Calling
read(2) for the file descriptor returned by
fanotify_init(2) blocks (if the flag
FAN_NONBLOCK is not
specified in the call to
fanotify_init(2)) until either a file event
occurs or the call is interrupted by a signal (see
signal(7)).
The use of the
FAN_REPORT_FID flag in
fanotify_init(2) influences
what data structures are returned to the event listener for each event. After
a successful
read(2), the read buffer contains one or more of the
following structures:
struct fanotify_event_metadata {
__u32 event_len;
__u8 vers;
__u8 reserved;
__u16 metadata_len;
__aligned_u64 mask;
__s32 fd;
__s32 pid;
};
In the case where
FAN_REPORT_FID is supplied as one of the flags to
fanotify_init(2), you should also expect to receive the structure
detailed below following the generic
fanotify_event_metadata structure
within the read buffer:
struct fanotify_event_info_fid {
struct fanotify_event_info_header hdr;
__kernel_fsid_t fsid;
unsigned char file_handle[0];
};
For performance reasons, it is recommended to use a large buffer size (for
example, 4096 bytes), so that multiple events can be retrieved by a single
read(2).
The return value of
read(2) is the number of bytes placed in the buffer,
or -1 in case of an error (but see BUGS).
The fields of the
fanotify_event_metadata structure are as follows:
- event_len
- This is the length of the data for the current event and the offset to the
next event in the buffer. Without FAN_REPORT_FID, the value of
event_len is always FAN_EVENT_METADATA_LEN. With
FAN_REPORT_FID, event_len also includes the variable length
file identifier.
- vers
- This field holds a version number for the structure. It must be compared
to FANOTIFY_METADATA_VERSION to verify that the structures returned
at run time match the structures defined at compile time. In case of a
mismatch, the application should abandon trying to use the fanotify file
descriptor.
- reserved
- This field is not used.
- metadata_len
- This is the length of the structure. The field was introduced to
facilitate the implementation of optional headers per event type. No such
optional headers exist in the current implementation.
- mask
- This is a bit mask describing the event (see below).
- fd
- This is an open file descriptor for the object being accessed, or
FAN_NOFD if a queue overflow occurred. If the fanotify file
descriptor has been initialized using FAN_REPORT_FID, applications
should expect this value to be set to FAN_NOFD for each event that
is received. The file descriptor can be used to access the contents of the
monitored file or directory. The reading application is responsible for
closing this file descriptor.
- When calling fanotify_init(2), the caller may specify (via the
event_f_flags argument) various file status flags that are to be
set on the open file description that corresponds to this file descriptor.
In addition, the (kernel-internal) FMODE_NONOTIFY file status flag
is set on the open file description. This flag suppresses fanotify event
generation. Hence, when the receiver of the fanotify event accesses the
notified file or directory using this file descriptor, no additional
events will be created.
- pid
- If flag FAN_REPORT_TID was set in fanotify_init(2), this is
the TID of the thread that caused the event. Otherwise, this the PID of
the process that caused the event.
A program listening to fanotify events can compare this PID to the PID returned
by
getpid(2), to determine whether the event is caused by the listener
itself, or is due to a file access by another process.
The bit mask in
mask indicates which events have occurred for a single
filesystem object. Multiple bits may be set in this mask, if more than one
event occurred for the monitored filesystem object. In particular, consecutive
events for the same filesystem object and originating from the same process
may be merged into a single event, with the exception that two permission
events are never merged into one queue entry.
The bits that may appear in
mask are as follows:
- FAN_ACCESS
- A file or a directory (but see BUGS) was accessed (read).
- FAN_OPEN
- A file or a directory was opened.
- FAN_OPEN_EXEC
- A file was opened with the intent to be executed. See NOTES in
fanotify_mark(2) for additional details.
- FAN_ATTRIB
- A file or directory metadata was changed.
- FAN_CREATE
- A child file or directory was created in a watched parent.
- FAN_DELETE
- A child file or directory was deleted in a watched parent.
- FAN_DELETE_SELF
- A watched file or directory was deleted.
- FAN_MOVED_FROM
- A file or directory has been moved from a watched parent directory.
- FAN_MOVED_TO
- A file or directory has been moved to a watched parent directory.
- FAN_MOVE_SELF
- A watched file or directory was moved.
- FAN_MODIFY
- A file was modified.
- FAN_CLOSE_WRITE
- A file that was opened for writing (O_WRONLY or O_RDWR) was
closed.
- FAN_CLOSE_NOWRITE
- A file or directory that was opened read-only (O_RDONLY) was
closed.
- FAN_Q_OVERFLOW
- The event queue exceeded the limit of 16384 entries. This limit can be
overridden by specifying the FAN_UNLIMITED_QUEUE flag when calling
fanotify_init(2).
- FAN_ACCESS_PERM
- An application wants to read a file or directory, for example using
read(2) or readdir(2). The reader must write a response (as
described below) that determines whether the permission to access the
filesystem object shall be granted.
- FAN_OPEN_PERM
- An application wants to open a file or directory. The reader must write a
response that determines whether the permission to open the filesystem
object shall be granted.
- FAN_OPEN_EXEC_PERM
- An application wants to open a file for execution. The reader must write a
response that determines whether the permission to open the filesystem
object for execution shall be granted. See NOTES in
fanotify_mark(2) for additional details.
To check for any close event, the following bit mask may be used:
- FAN_CLOSE
- A file was closed. This is a synonym for:
-
FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE
To check for any move event, the following bit mask may be used:
- FAN_MOVE
- A file or directory was moved. This is a synonym for:
-
FAN_MOVED_FROM | FAN_MOVED_TO
The fields of the
fanotify_event_info_fid structure are as follows:
- hdr
- This is a structure of type fanotify_event_info_header. It is a
generic header that contains information used to describe additional
information attached to the event. For example, when an fanotify file
descriptor is created using FAN_REPORT_FID, the info_type
field of this header is set to FAN_EVENT_INFO_TYPE_FID. Event
listeners can use this field to check that the additional information
received for an event is of the correct type. Additionally, the
fanotify_event_info_header also contains a len field. In the
current implementation, the value of len is always (event_len -
FAN_EVENT_METADATA_LEN).
- fsid
- This is a unique identifier of the filesystem containing the object
associated with the event. It is a structure of type
__kernel_fsid_t and contains the same value as f_fsid when
calling statfs(2).
- file_handle
- This is a variable length structure of type file_handle. It is an
opaque handle that corresponds to a specified object on a filesystem as
returned by name_to_handle_at(2). It can be used to uniquely
identify a file on a filesystem and can be passed as an argument to
open_by_handle_at(2). Note that for directory entry events, such as
FAN_CREATE, FAN_DELETE, and FAN_MOVE, the
file_handle describes the modified directory and not the
created/deleted/moved child object. The events FAN_ATTRIB,
FAN_DELETE_SELF, and FAN_MOVE_SELF will carry the
file_handle information for the child object if the child object is
being watched.
The following macros are provided to iterate over a buffer containing fanotify
event metadata returned by a
read(2) from an fanotify file descriptor:
- FAN_EVENT_OK(meta, len)
- This macro checks the remaining length len of the buffer
meta against the length of the metadata structure and the
event_len field of the first metadata structure in the buffer.
- FAN_EVENT_NEXT(meta, len)
- This macro uses the length indicated in the event_len field of the
metadata structure pointed to by meta to calculate the address of
the next metadata structure that follows meta. len is the
number of bytes of metadata that currently remain in the buffer. The macro
returns a pointer to the next metadata structure that follows meta,
and reduces len by the number of bytes in the metadata structure
that has been skipped over (i.e., it subtracts meta->event_len
from len).
In addition, there is:
- FAN_EVENT_METADATA_LEN
- This macro returns the size (in bytes) of the structure
fanotify_event_metadata. This is the minimum size (and currently
the only size) of any event metadata.
When an fanotify event occurs, the fanotify file descriptor indicates as
readable when passed to
epoll(7),
poll(2), or
select(2).
For permission events, the application must
write(2) a structure of the
following form to the fanotify file descriptor:
struct fanotify_response {
__s32 fd;
__u32 response;
};
The fields of this structure are as follows:
- fd
- This is the file descriptor from the structure
fanotify_event_metadata.
- response
- This field indicates whether or not the permission is to be granted. Its
value must be either FAN_ALLOW to allow the file operation or
FAN_DENY to deny the file operation.
If access is denied, the requesting application call will receive an
EPERM error.
When all file descriptors referring to the fanotify notification group are
closed, the fanotify group is released and its resources are freed for reuse
by the kernel. Upon
close(2), outstanding permission events will be set
to allowed.
The file
/proc/[pid]/fdinfo/[fd] contains information about fanotify
marks for file descriptor
fd of process
pid. See
proc(5)
for details.
In addition to the usual errors for
read(2), the following errors can
occur when reading from the fanotify file descriptor:
- EINVAL
- The buffer is too small to hold the event.
- EMFILE
- The per-process limit on the number of open files has been reached. See
the description of RLIMIT_NOFILE in getrlimit(2).
- ENFILE
- The system-wide limit on the total number of open files has been reached.
See /proc/sys/fs/file-max in proc(5).
- ETXTBSY
- This error is returned by read(2) if O_RDWR or
O_WRONLY was specified in the event_f_flags argument when
calling fanotify_init(2) and an event occurred for a monitored file
that is currently being executed.
In addition to the usual errors for
write(2), the following errors can
occur when writing to the fanotify file descriptor:
- EINVAL
- Fanotify access permissions are not enabled in the kernel configuration or
the value of response in the response structure is not valid.
- ENOENT
- The file descriptor fd in the response structure is not valid. This
may occur when a response for the permission event has already been
written.
The fanotify API was introduced in version 2.6.36 of the Linux kernel and
enabled in version 2.6.37. Fdinfo support was added in version 3.8.
The fanotify API is Linux-specific.
The fanotify API is available only if the kernel was built with the
CONFIG_FANOTIFY configuration option enabled. In addition, fanotify
permission handling is available only if the
CONFIG_FANOTIFY_ACCESS_PERMISSIONS configuration option is enabled.
Fanotify reports only events that a user-space program triggers through the
filesystem API. As a result, it does not catch remote events that occur on
network filesystems.
The fanotify API does not report file accesses and modifications that may occur
because of
mmap(2),
msync(2), and
munmap(2).
Events for directories are created only if the directory itself is opened, read,
and closed. Adding, removing, or changing children of a marked directory does
not create events for the monitored directory itself.
Fanotify monitoring of directories is not recursive: to monitor subdirectories
under a directory, additional marks must be created. (But note that the
fanotify API provides no way of detecting when a subdirectory has been created
under a marked directory, which makes recursive monitoring difficult.)
Monitoring mounts offers the capability to monitor a whole directory tree.
Monitoring filesystems offers the capability to monitor changes made from any
mount of a filesystem instance.
The event queue can overflow. In this case, events are lost.
Before Linux 3.19,
fallocate(2) did not generate fanotify events. Since
Linux 3.19, calls to
fallocate(2) generate
FAN_MODIFY events.
As of Linux 3.17, the following bugs exist:
- *
- On Linux, a filesystem object may be accessible through multiple paths,
for example, a part of a filesystem may be remounted using the
--bind option of mount(8). A listener that marked a mount
will be notified only of events that were triggered for a filesystem
object using the same mount. Any other event will pass unnoticed.
- *
- When an event is generated, no check is made to see whether the user ID of
the receiving process has authorization to read or write the file before
passing a file descriptor for that file. This poses a security risk, when
the CAP_SYS_ADMIN capability is set for programs executed by
unprivileged users.
- *
- If a call to read(2) processes multiple events from the fanotify
queue and an error occurs, the return value will be the total length of
the events successfully copied to the user-space buffer before the error
occurred. The return value will not be -1, and errno will not be
set. Thus, the reading application has no way to detect the error.
The two example programs below demonstrate the usage of the fanotify API.
The first program is an example of fanotify being used with its event object
information passed in the form of a file descriptor. The program marks the
mount point passed as a command-line argument and waits for events of type
FAN_OPEN_PERM and
FAN_CLOSE_WRITE. When a permission event
occurs, a
FAN_ALLOW response is given.
The following shell session shows an example of running this program. This
session involved editing the file
/home/user/temp/notes. Before the
file was opened, a
FAN_OPEN_PERM event occurred. After the file was
closed, a
FAN_CLOSE_WRITE event occurred. Execution of the program ends
when the user presses the ENTER key.
# ./fanotify_example /home
Press enter key to terminate.
Listening for events.
FAN_OPEN_PERM: File /home/user/temp/notes
FAN_CLOSE_WRITE: File /home/user/temp/notes
Listening for events stopped.
#define _GNU_SOURCE /* Needed to get O_LARGEFILE definition */
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/fanotify.h>
#include <unistd.h>
/* Read all available fanotify events from the file descriptor 'fd' */
static void
handle_events(int fd)
{
const struct fanotify_event_metadata *metadata;
struct fanotify_event_metadata buf[200];
ssize_t len;
char path[PATH_MAX];
ssize_t path_len;
char procfd_path[PATH_MAX];
struct fanotify_response response;
/* Loop while events can be read from fanotify file descriptor */
for (;;) {
/* Read some events */
len = read(fd, (void *) &buf, sizeof(buf));
if (len == -1 && errno != EAGAIN) {
perror("read");
exit(EXIT_FAILURE);
}
/* Check if end of available data reached */
if (len <= 0)
break;
/* Point to the first event in the buffer */
metadata = buf;
/* Loop over all events in the buffer */
while (FAN_EVENT_OK(metadata, len)) {
/* Check that run-time and compile-time structures match */
if (metadata->vers != FANOTIFY_METADATA_VERSION) {
fprintf(stderr,
"Mismatch of fanotify metadata version.\n");
exit(EXIT_FAILURE);
}
/* metadata->fd contains either FAN_NOFD, indicating a
queue overflow, or a file descriptor (a nonnegative
integer). Here, we simply ignore queue overflow. */
if (metadata->fd >= 0) {
/* Handle open permission event */
if (metadata->mask & FAN_OPEN_PERM) {
printf("FAN_OPEN_PERM: ");
/* Allow file to be opened */
response.fd = metadata->fd;
response.response = FAN_ALLOW;
write(fd, &response,
sizeof(struct fanotify_response));
}
/* Handle closing of writable file event */
if (metadata->mask & FAN_CLOSE_WRITE)
printf("FAN_CLOSE_WRITE: ");
/* Retrieve and print pathname of the accessed file */
snprintf(procfd_path, sizeof(procfd_path),
"/proc/self/fd/%d", metadata->fd);
path_len = readlink(procfd_path, path,
sizeof(path) - 1);
if (path_len == -1) {
perror("readlink");
exit(EXIT_FAILURE);
}
path[path_len] = '\0';
printf("File %s\n", path);
/* Close the file descriptor of the event */
close(metadata->fd);
}
/* Advance to next event */
metadata = FAN_EVENT_NEXT(metadata, len);
}
}
}
int
main(int argc, char *argv[])
{
char buf;
int fd, poll_num;
nfds_t nfds;
struct pollfd fds[2];
/* Check mount point is supplied */
if (argc != 2) {
fprintf(stderr, "Usage: %s MOUNT\n", argv[0]);
exit(EXIT_FAILURE);
}
printf("Press enter key to terminate.\n");
/* Create the file descriptor for accessing the fanotify API */
fd = fanotify_init(FAN_CLOEXEC | FAN_CLASS_CONTENT | FAN_NONBLOCK,
O_RDONLY | O_LARGEFILE);
if (fd == -1) {
perror("fanotify_init");
exit(EXIT_FAILURE);
}
/* Mark the mount for:
- permission events before opening files
- notification events after closing a write-enabled
file descriptor */
if (fanotify_mark(fd, FAN_MARK_ADD | FAN_MARK_MOUNT,
FAN_OPEN_PERM | FAN_CLOSE_WRITE, AT_FDCWD,
argv[1]) == -1) {
perror("fanotify_mark");
exit(EXIT_FAILURE);
}
/* Prepare for polling */
nfds = 2;
/* Console input */
fds[0].fd = STDIN_FILENO;
fds[0].events = POLLIN;
/* Fanotify input */
fds[1].fd = fd;
fds[1].events = POLLIN;
/* This is the loop to wait for incoming events */
printf("Listening for events.\n");
while (1) {
poll_num = poll(fds, nfds, -1);
if (poll_num == -1) {
if (errno == EINTR) /* Interrupted by a signal */
continue; /* Restart poll() */
perror("poll"); /* Unexpected error */
exit(EXIT_FAILURE);
}
if (poll_num > 0) {
if (fds[0].revents & POLLIN) {
/* Console input is available: empty stdin and quit */
while (read(STDIN_FILENO, &buf, 1) > 0 && buf != '\n')
continue;
break;
}
if (fds[1].revents & POLLIN) {
/* Fanotify events are available */
handle_events(fd);
}
}
}
printf("Listening for events stopped.\n");
exit(EXIT_SUCCESS);
}
The second program is an example of fanotify being used with
FAN_REPORT_FID enabled. The program marks the filesystem object that is
passed as a command-line argument and waits until an event of type
FAN_CREATE has occurred. The event mask indicates which type of
filesystem object—either a file or a directory—was created. Once
all events have been read from the buffer and processed accordingly, the
program simply terminates.
The following shell sessions show two different invocations of this program,
with different actions performed on a watched object.
The first session shows a mark being placed on
/home/user. This is
followed by the creation of a regular file,
/home/user/testfile.txt.
This results in a
FAN_CREATE event being created and reported against
the file's parent watched directory object. Program execution ends once all
events captured within the buffer have been processed. Program execution ends
once all events captured within the buffer are processed.
# ./fanotify_fid /home/user
Listening for events.
FAN_CREATE (file created): Directory /home/user has been modified.
All events processed successfully. Program exiting.
$ touch /home/user/testing # In another terminal
The second session shows a mark being placed on
/home/user. This is
followed by the creation of a directory,
/home/user/testdir. This
specific action results in the program producing a
FAN_CREATE and
FAN_ONDIR event.
# ./fanotify_fid /home/user
Listening for events.
FAN_CREATE | FAN_ONDIR (subdirectory created):
Directory /home/user has been modified.
All events processed successfully. Program exiting.
$ mkdir -p /home/user/testing # In another terminal
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/fanotify.h>
#include <unistd.h>
#define BUF_SIZE 256
int
main(int argc, char **argv)
{
int fd, ret, event_fd;
ssize_t len, path_len;
char path[PATH_MAX];
char procfd_path[PATH_MAX];
char events_buf[BUF_SIZE];
struct file_handle *file_handle;
struct fanotify_event_metadata *metadata;
struct fanotify_event_info_fid *fid;
if (argc != 2) {
fprintf(stderr, "Invalid number of command line arguments.\n");
exit(EXIT_FAILURE);
}
/* Create an fanotify file descriptor with FAN_REPORT_FID as a flag
so that program can receive fid events. */
fd = fanotify_init(FAN_CLASS_NOTIF | FAN_REPORT_FID, 0);
if (fd == -1) {
perror("fanotify_init");
exit(EXIT_FAILURE);
}
/* Place a mark on the filesystem object supplied in argv[1]. */
ret = fanotify_mark(fd, FAN_MARK_ADD | FAN_MARK_ONLYDIR,
FAN_CREATE | FAN_ONDIR,
AT_FDCWD, argv[1]);
if (ret == -1) {
perror("fanotify_mark");
exit(EXIT_FAILURE);
}
printf("Listening for events.\n");
/* Read events from the event queue into a buffer */
len = read(fd, (void *) &events_buf, sizeof(events_buf));
if (len == -1 && errno != EAGAIN) {
perror("read");
exit(EXIT_FAILURE);
}
/* Process all events within the buffer */
for (metadata = (struct fanotify_event_metadata *) events_buf;
FAN_EVENT_OK(metadata, len);
metadata = FAN_EVENT_NEXT(metadata, len)) {
fid = (struct fanotify_event_info_fid *) (metadata + 1);
file_handle = (struct file_handle *) fid->handle;
/* Ensure that the event info is of the correct type */
if (fid->hdr.info_type != FAN_EVENT_INFO_TYPE_FID) {
fprintf(stderr, "Received unexpected event info type.\n");
exit(EXIT_FAILURE);
}
if (metadata->mask == FAN_CREATE)
printf("FAN_CREATE (file created):");
if (metadata->mask == FAN_CREATE | FAN_ONDIR)
printf("FAN_CREATE | FAN_ONDIR (subdirectory created):");
/* metadata->fd is set to FAN_NOFD when FAN_REPORT_FID is enabled.
To obtain a file descriptor for the file object corresponding to
an event you can use the struct file_handle that's provided
within the fanotify_event_info_fid in conjunction with the
open_by_handle_at(2) system call. A check for ESTALE is done
to accommodate for the situation where the file handle for the
object was deleted prior to this system call. */
event_fd = open_by_handle_at(AT_FDCWD, file_handle, O_RDONLY);
if (ret == -1) {
if (errno == ESTALE) {
printf("File handle is no longer valid. "
"File has been deleted\n");
continue;
} else {
perror("open_by_handle_at");
exit(EXIT_FAILURE);
}
}
snprintf(procfd_path, sizeof(procfd_path), "/proc/self/fd/%d",
event_fd);
/* Retrieve and print the path of the modified dentry */
path_len = readlink(procfd_path, path, sizeof(path) - 1);
if (path_len == -1) {
perror("readlink");
exit(EXIT_FAILURE);
}
path[path_len] = '\0';
printf("\tDirectory '%s' has been modified.\n", path);
/* Close associated file descriptor for this event */
close(event_fd);
}
printf("All events processed successfully. Program exiting.\n");
exit(EXIT_SUCCESS);
}
fanotify_init(2),
fanotify_mark(2),
inotify(7)