1FANOTIFY_MARK(2) Linux Programmer's Manual FANOTIFY_MARK(2)
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6 fanotify_mark - add, remove, or modify an fanotify mark on a filesystem
7 object
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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
30 ignore mask). mask must be nonempty or the error EINVAL will
31 occur.
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
42 removed 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 point specified by pathname. If pathname is not
66 itself a mount point, the mount point containing pathname will
67 be marked. All directories, subdirectories, and the contained
68 files of the mount point will be monitored. This value cannot
69 be used if the fanotify_fd file descriptor has been initialized
70 with the flag FAN_REPORT_FID or if any of the new directory mod‐
71 ification events are provided as a mask. 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
90 ignored). 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
94 accessed (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.
115 FAN_CREATE (since Linux 5.1)
117 Create an event when a file or directory has been created in a
118 marked parent directory.
119 FAN_DELETE (since Linux 5.1)
121 Create an event when a file or directory has been deleted in a
122 marked parent directory.
123 FAN_DELETE_SELF (since Linux 5.1)
125 Create an event when a marked file or directory itself is
126 deleted.
127 FAN_MOVED_FROM (since Linux 5.1)
129 Create an event when a file or directory has been moved from a
130 marked parent directory.
131 FAN_MOVED_TO (since Linux 5.1)
133 Create an event when a file or directory has been moved to a
134 marked parent directory.
135 FAN_MOVE_SELF (since Linux 5.1)
137 Create an event when a marked file or directory itself has been
138 moved.
139 FAN_Q_OVERFLOW
141 Create an event when an overflow of the event queue occurs. The
142 size of the event queue is limited to 16384 entries if
143 FAN_UNLIMITED_QUEUE is not set in fanotify_init(2).
144 FAN_OPEN_PERM
146 Create an event when a permission to open a file or directory is
147 requested. An fanotify file descriptor created with
148 FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required.
149 FAN_OPEN_EXEC_PERM (since Linux 5.0)
151 Create an event when a permission to open a file for execution
152 is requested. An fanotify file descriptor created with
153 FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required. See
154 NOTES for additional details.
155 FAN_ACCESS_PERM
157 Create an event when a permission to read a file or directory is
158 requested. An fanotify file descriptor created with
159 FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required.
160 FAN_ONDIR
162 Create events for directories—for example, when opendir(3),
163 readdir(3) (but see BUGS), and closedir(3) are called. Without
164 this flag, only events for files are created. The FAN_ONDIR
165 flag is reported in an event mask only if the fanotify_fd file
166 descriptor has been initialized with the flag FAN_REPORT_FID.
167 In the context of directory entry events, such as FAN_CREATE,
168 FAN_DELETE, FAN_MOVED_FROM, and FAN_MOVED_TO for example, speci‐
169 fying the flag FAN_ONDIR is required in order to create events
170 when subdirectory entries are modified (i.e., mkdir(2)/
171 rmdir(2)). Subdirectory entry modification events will never be
172 merged with nonsubdirectory entry modification events. This
173 flag is never reported individually within an event and is
174 always supplied in conjunction with another event type.
175 FAN_EVENT_ON_CHILD
177 Events for the immediate children of marked directories shall be
178 created. The flag has no effect when marking mounts and
179 filesystems. Note that events are not generated for children of
180 the subdirectories of marked directories. To monitor complete
181 directory trees it is necessary to mark the relevant mount.
182 The following composed values are defined:
184 FAN_CLOSE
186 A file is closed (FAN_CLOSE_WRITE|FAN_CLOSE_NOWRITE).
187 FAN_MOVE
189 A file or directory has been moved
190 (FAN_MOVED_FROM|FAN_MOVED_TO).
191 The filesystem object to be marked is determined by the file descriptor
193 dirfd and the pathname specified in pathname:
194 * If pathname is NULL, dirfd defines the filesystem object to be
196 marked.
197 * If pathname is NULL, and dirfd takes the special value AT_FDCWD, the
199 current working directory is to be marked.
200 * If pathname is absolute, it defines the filesystem object to be
202 marked, and dirfd is ignored.
203 * If pathname is relative, and dirfd does not have the value AT_FDCWD,
205 then the filesystem object to be marked is determined by interpret‐
206 ing pathname relative the directory referred to by dirfd.
207 * If pathname is relative, and dirfd has the value AT_FDCWD, then the
209 filesystem object to be marked is determined by interpreting path‐
210 name relative the current working directory.
211
213 On success, fanotify_mark() returns 0. On error, -1 is returned, and
214 errno is set to indicate the error.
215
217 EBADF An invalid file descriptor was passed in fanotify_fd.
218 EINVAL An invalid value was passed in flags or mask, or fanotify_fd was
220 not an fanotify file descriptor.
221 EINVAL The fanotify file descriptor was opened with FAN_CLASS_NOTIF or
223 FAN_REPORT_FID and mask contains a flag for permission events
224 (FAN_OPEN_PERM or FAN_ACCESS_PERM).
225 ENODEV The filesystem object indicated by pathname is not associated
227 with a filesystem that supports fsid (e.g., tmpfs(5)). This
228 error can be returned only when an fanotify file descriptor
229 returned by fanotify_init(2) has been created with
230 FAN_REPORT_FID.
231 ENOENT The filesystem object indicated by dirfd and pathname does not
233 exist. This error also occurs when trying to remove a mark from
234 an object which is not marked.
235 ENOMEM The necessary memory could not be allocated.
237 ENOSPC The number of marks exceeds the limit of 8192 and the FAN_UNLIM‐
239 ITED_MARKS flag was not specified when the fanotify file
240 descriptor was created with fanotify_init(2).
241 ENOSYS This kernel does not implement fanotify_mark(). The fanotify
243 API is available only if the kernel was configured with CON‐
244 FIG_FANOTIFY.
245 ENOTDIR
247 flags contains FAN_MARK_ONLYDIR, and dirfd and pathname do not
248 specify a directory.
249 EOPNOTSUPP
251 The object indicated by pathname is associated with a filesystem
252 that does not support the encoding of file handles. This error
253 can be returned only when an fanotify file descriptor returned
254 by fanotify_init(2) has been created with FAN_REPORT_FID.
255 EXDEV The filesystem object indicated by pathname resides within a
257 filesystem subvolume (e.g., btrfs(5)) which uses a different
258 fsid than its root superblock. This error can be returned only
259 when an fanotify file descriptor returned by fanotify_init(2)
260 has been created with FAN_REPORT_FID.
261
263 fanotify_mark() was introduced in version 2.6.36 of the Linux kernel
264 and enabled in version 2.6.37.
265
267 This system call is Linux-specific.
268
270 FAN_OPEN_EXEC and FAN_OPEN_EXEC_PERM
271 When using either FAN_OPEN_EXEC or FAN_OPEN_EXEC_PERM within the mask,
272 events of these types will be returned only when the direct execution
273 of a program occurs. More specifically, this means that events of
274 these types will be generated for files that are opened using
275 execve(2), execveat(2), or uselib(2). Events of these types will not
276 be raised in the situation where an interpreter is passed (or reads) a
277 script file for interpretation.
278 Additionally, if a mark has also been placed on the Linux dynamic
280 linker, a user should also expect to receive an event for it when an
281 ELF object has been successfully opened using execve(2) or execveat(2).
282 For example, if the following ELF binary were to be invoked and a
284 FAN_OPEN_EXEC mark has been placed on /:
285 $ /bin/echo foo
287 The listening application in this case would receive FAN_OPEN_EXEC
289 events for both the ELF binary and interpreter, respectively:
290 /bin/echo
292 /lib64/ld-linux-x86-64.so.2
293
295 The following bugs were present in Linux kernels before version 3.16:
296 * If flags contains FAN_MARK_FLUSH, dirfd and pathname must specify a
298 valid filesystem object, even though this object is not used.
299 * readdir(2) does not generate a FAN_ACCESS event.
301 * If fanotify_mark() is called with FAN_MARK_FLUSH, flags is not
303 checked for invalid values.
304
306 fanotify_init(2), fanotify(7)
307
309 This page is part of release 5.04 of the Linux man-pages project. A
310 description of the project, information about reporting bugs, and the
311 latest version of this page, can be found at
312 https://www.kernel.org/doc/man-pages/.
313Linux 2019-08-02 FANOTIFY_MARK(2)