1FANOTIFY_MARK(2) Linux Programmer's Manual FANOTIFY_MARK(2)
2
6 fanotify_mark - add, remove, or modify an fanotify mark on a filesystem
7 object
8
10 #include <sys/fanotify.h>
11 int fanotify_mark(int fanotify_fd, unsigned int flags,
13 uint64_t mask, int dirfd, const char *pathname);
14
16 For an overview of the fanotify API, see fanotify(7).
17 fanotify_mark() adds, removes, or modifies an fanotify mark on a
19 filesystem object. The caller must have read permission on the
20 filesystem object that is to be marked.
21 The fanotify_fd argument is a file descriptor returned by fan‐
23 otify_init(2).
24 flags is a bit mask describing the modification to perform. It must
26 include exactly one of the following values:
27 FAN_MARK_ADD
29 The events in mask will be added to the mark mask (or to the ig‐
30 nore mask). mask must be nonempty or the error EINVAL will oc‐
31 cur.
32 FAN_MARK_REMOVE
34 The events in argument mask will be removed from the mark mask
35 (or from the ignore mask). mask must be nonempty or the error
36 EINVAL will occur.
37 FAN_MARK_FLUSH
39 Remove either all marks for filesystems, all marks for mounts,
40 or all marks for directories and files from the fanotify group.
41 If flags contains FAN_MARK_MOUNT, all marks for mounts are re‐
42 moved from the group. If flags contains FAN_MARK_FILESYSTEM,
43 all marks for filesystems are removed from the group. Other‐
44 wise, all marks for directories and files are removed. No flag
45 other than, and at most one of, the flags FAN_MARK_MOUNT or
46 FAN_MARK_FILESYSTEM can be used in conjunction with
47 FAN_MARK_FLUSH. mask is ignored.
48 If none of the values above is specified, or more than one is speci‐
50 fied, the call fails with the error EINVAL.
51 In addition, zero or more of the following values may be ORed into
53 flags:
54 FAN_MARK_DONT_FOLLOW
56 If pathname is a symbolic link, mark the link itself, rather
57 than the file to which it refers. (By default, fanotify_mark()
58 dereferences pathname if it is a symbolic link.)
59 FAN_MARK_ONLYDIR
61 If the filesystem object to be marked is not a directory, the
62 error ENOTDIR shall be raised.
63 FAN_MARK_MOUNT
65 Mark the mount specified by pathname. If pathname is not itself
66 a mount point, the mount containing pathname will be marked.
67 All directories, subdirectories, and the contained files of the
68 mount will be monitored. The events which require that filesys‐
69 tem objects are identified by file handles, such as FAN_CREATE,
70 FAN_ATTRIB, FAN_MOVE, and FAN_DELETE_SELF, cannot be provided as
71 a mask when flags contains FAN_MARK_MOUNT. Attempting to do so
72 will result in the error EINVAL being returned.
73 FAN_MARK_FILESYSTEM (since Linux 4.20)
75 Mark the filesystem specified by pathname. The filesystem con‐
76 taining pathname will be marked. All the contained files and
77 directories of the filesystem from any mount point will be moni‐
78 tored.
79 FAN_MARK_IGNORED_MASK
81 The events in mask shall be added to or removed from the ignore
82 mask.
83 FAN_MARK_IGNORED_SURV_MODIFY
85 The ignore mask shall survive modify events. If this flag is
86 not set, the ignore mask is cleared when a modify event occurs
87 for the ignored file or directory.
88 mask defines which events shall be listened for (or which shall be ig‐
90 nored). It is a bit mask composed of the following values:
91 FAN_ACCESS
93 Create an event when a file or directory (but see BUGS) is ac‐
94 cessed (read).
95 FAN_MODIFY
97 Create an event when a file is modified (write).
98 FAN_CLOSE_WRITE
100 Create an event when a writable file is closed.
101 FAN_CLOSE_NOWRITE
103 Create an event when a read-only file or directory is closed.
104 FAN_OPEN
106 Create an event when a file or directory is opened.
107 FAN_OPEN_EXEC (since Linux 5.0)
109 Create an event when a file is opened with the intent to be exe‐
110 cuted. See NOTES for additional details.
111 FAN_ATTRIB (since Linux 5.1)
113 Create an event when the metadata for a file or directory has
114 changed. An fanotify group that identifies filesystem objects
115 by file handles is required.
116 FAN_CREATE (since Linux 5.1)
118 Create an event when a file or directory has been created in a
119 marked parent directory. An fanotify group that identifies
120 filesystem objects by file handles is required.
121 FAN_DELETE (since Linux 5.1)
123 Create an event when a file or directory has been deleted in a
124 marked parent directory. An fanotify group that identifies
125 filesystem objects by file handles is required.
126 FAN_DELETE_SELF (since Linux 5.1)
128 Create an event when a marked file or directory itself is
129 deleted. An fanotify group that identifies filesystem objects
130 by file handles is required.
131 FAN_MOVED_FROM (since Linux 5.1)
133 Create an event when a file or directory has been moved from a
134 marked parent directory. An fanotify group that identifies
135 filesystem objects by file handles is required.
136 FAN_MOVED_TO (since Linux 5.1)
138 Create an event when a file or directory has been moved to a
139 marked parent directory. An fanotify group that identifies
140 filesystem objects by file handles is required.
141 FAN_MOVE_SELF (since Linux 5.1)
143 Create an event when a marked file or directory itself has been
144 moved. An fanotify group that identifies filesystem objects by
145 file handles is required.
146 FAN_OPEN_PERM
148 Create an event when a permission to open a file or directory is
149 requested. An fanotify file descriptor created with
150 FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required.
151 FAN_OPEN_EXEC_PERM (since Linux 5.0)
153 Create an event when a permission to open a file for execution
154 is requested. An fanotify file descriptor created with
155 FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required. See
156 NOTES for additional details.
157 FAN_ACCESS_PERM
159 Create an event when a permission to read a file or directory is
160 requested. An fanotify file descriptor created with
161 FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required.
162 FAN_ONDIR
164 Create events for directories—for example, when opendir(3),
165 readdir(3) (but see BUGS), and closedir(3) are called. Without
166 this flag, events are created only for files. In the context of
167 directory entry events, such as FAN_CREATE, FAN_DELETE,
168 FAN_MOVED_FROM, and FAN_MOVED_TO, specifying the flag FAN_ONDIR
169 is required in order to create events when subdirectory entries
170 are modified (i.e., mkdir(2)/ rmdir(2)).
171 FAN_EVENT_ON_CHILD
173 Events for the immediate children of marked directories shall be
174 created. The flag has no effect when marking mounts and
175 filesystems. Note that events are not generated for children of
176 the subdirectories of marked directories. More specifically,
177 the directory entry modification events FAN_CREATE, FAN_DELETE,
178 FAN_MOVED_FROM, and FAN_MOVED_TO are not generated for any entry
179 modifications performed inside subdirectories of marked directo‐
180 ries. Note that the events FAN_DELETE_SELF and FAN_MOVE_SELF
181 are not generated for children of marked directories. To moni‐
182 tor complete directory trees it is necessary to mark the rele‐
183 vant mount or filesystem.
184 The following composed values are defined:
186 FAN_CLOSE
188 A file is closed (FAN_CLOSE_WRITE|FAN_CLOSE_NOWRITE).
189 FAN_MOVE
191 A file or directory has been moved
192 (FAN_MOVED_FROM|FAN_MOVED_TO).
193 The filesystem object to be marked is determined by the file descriptor
195 dirfd and the pathname specified in pathname:
196 * If pathname is NULL, dirfd defines the filesystem object to be
198 marked.
199 * If pathname is NULL, and dirfd takes the special value AT_FDCWD, the
201 current working directory is to be marked.
202 * If pathname is absolute, it defines the filesystem object to be
204 marked, and dirfd is ignored.
205 * If pathname is relative, and dirfd does not have the value AT_FDCWD,
207 then the filesystem object to be marked is determined by interpret‐
208 ing pathname relative the directory referred to by dirfd.
209 * If pathname is relative, and dirfd has the value AT_FDCWD, then the
211 filesystem object to be marked is determined by interpreting path‐
212 name relative to the current working directory. (See openat(2) for
213 an explanation of why the dirfd argument is useful.)
214
216 On success, fanotify_mark() returns 0. On error, -1 is returned, and
217 errno is set to indicate the error.
218
220 EBADF An invalid file descriptor was passed in fanotify_fd.
221 EBADF pathname is relative but dirfd is neither AT_FDCWD nor a valid
223 file descriptor.
224 EINVAL An invalid value was passed in flags or mask, or fanotify_fd was
226 not an fanotify file descriptor.
227 EINVAL The fanotify file descriptor was opened with FAN_CLASS_NOTIF or
229 the fanotify group identifies filesystem objects by file handles
230 and mask contains a flag for permission events (FAN_OPEN_PERM or
231 FAN_ACCESS_PERM).
232 ENODEV The filesystem object indicated by pathname is not associated
234 with a filesystem that supports fsid (e.g., tmpfs(5)). This er‐
235 ror can be returned only with an fanotify group that identifies
236 filesystem objects by file handles.
237 ENOENT The filesystem object indicated by dirfd and pathname does not
239 exist. This error also occurs when trying to remove a mark from
240 an object which is not marked.
241 ENOMEM The necessary memory could not be allocated.
243 ENOSPC The number of marks exceeds the limit of 8192 and the FAN_UNLIM‐
245 ITED_MARKS flag was not specified when the fanotify file de‐
246 scriptor was created with fanotify_init(2).
247 ENOSYS This kernel does not implement fanotify_mark(). The fanotify
249 API is available only if the kernel was configured with CON‐
250 FIG_FANOTIFY.
251 ENOTDIR
253 flags contains FAN_MARK_ONLYDIR, and dirfd and pathname do not
254 specify a directory.
255 EOPNOTSUPP
257 The object indicated by pathname is associated with a filesystem
258 that does not support the encoding of file handles. This error
259 can be returned only with an fanotify group that identifies
260 filesystem objects by file handles.
261 EXDEV The filesystem object indicated by pathname resides within a
263 filesystem subvolume (e.g., btrfs(5)) which uses a different
264 fsid than its root superblock. This error can be returned only
265 with an fanotify group that identifies filesystem objects by
266 file handles.
267
269 fanotify_mark() was introduced in version 2.6.36 of the Linux kernel
270 and enabled in version 2.6.37.
271
273 This system call is Linux-specific.
274
276 FAN_OPEN_EXEC and FAN_OPEN_EXEC_PERM
277 When using either FAN_OPEN_EXEC or FAN_OPEN_EXEC_PERM within the mask,
278 events of these types will be returned only when the direct execution
279 of a program occurs. More specifically, this means that events of
280 these types will be generated for files that are opened using ex‐
281 ecve(2), execveat(2), or uselib(2). Events of these types will not be
282 raised in the situation where an interpreter is passed (or reads) a
283 file for interpretation.
284 Additionally, if a mark has also been placed on the Linux dynamic
286 linker, a user should also expect to receive an event for it when an
287 ELF object has been successfully opened using execve(2) or execveat(2).
288 For example, if the following ELF binary were to be invoked and a
290 FAN_OPEN_EXEC mark has been placed on /:
291 $ /bin/echo foo
293 The listening application in this case would receive FAN_OPEN_EXEC
295 events for both the ELF binary and interpreter, respectively:
296 /bin/echo
298 /lib64/ld-linux-x86-64.so.2
299
301 The following bugs were present in Linux kernels before version 3.16:
302 * If flags contains FAN_MARK_FLUSH, dirfd, and pathname must specify a
304 valid filesystem object, even though this object is not used.
305 * readdir(2) does not generate a FAN_ACCESS event.
307 * If fanotify_mark() is called with FAN_MARK_FLUSH, flags is not
309 checked for invalid values.
310
312 fanotify_init(2), fanotify(7)
313
315 This page is part of release 5.13 of the Linux man-pages project. A
316 description of the project, information about reporting bugs, and the
317 latest version of this page, can be found at
318 https://www.kernel.org/doc/man-pages/.
319Linux 2021-08-27 FANOTIFY_MARK(2)