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
113 Create an event when the metadata for a file or directory has
114 changed.
115 FAN_CREATE
117 Create an event when a file or directory has been created in a
118 marked parent directory.
119 FAN_DELETE
121 Create an event when a file or directory has been deleted in a
122 marked parent directory.
123 FAN_DELETE_SELF
125 Create an event when a marked file or directory itself is
126 deleted.
127 FAN_MOVED_FROM
129 Create an event when a file or directory has been moved from a
130 marked parent directory.
131 FAN_MOVED_TO
133 Create an event when a file or directory has been moved to a
134 marked parent directory.
135 FAN_Q_OVERFLOW
137 Create an event when an overflow of the event queue occurs. The
138 size of the event queue is limited to 16384 entries if
139 FAN_UNLIMITED_QUEUE is not set in fanotify_init(2).
140 FAN_OPEN_PERM
142 Create an event when a permission to open a file or directory is
143 requested. An fanotify file descriptor created with
144 FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required.
145 FAN_OPEN_EXEC_PERM (since Linux 5.0)
147 Create an event when a permission to open a file for execution
148 is requested. An fanotify file descriptor created with
149 FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required. See
150 NOTES for additional details.
151 FAN_ACCESS_PERM
153 Create an event when a permission to read a file or directory is
154 requested. An fanotify file descriptor created with
155 FAN_CLASS_PRE_CONTENT or FAN_CLASS_CONTENT is required.
156 FAN_ONDIR
158 Create events for directories—for example, when opendir(3),
159 readdir(3) (but see BUGS), and closedir(3) are called. Without
160 this flag, only events for files are created. The FAN_ONDIR
161 flag is reported in an event mask only if the fanotify_fd file
162 descriptor has been initialized with the flag FAN_REPORT_FID.
163 In the context of directory entry events, such as FAN_CREATE,
164 FAN_DELETE, FAN_MOVED_FROM, and FAN_MOVED_TO for example, speci‐
165 fying the flag FAN_ONDIR is required in order to create events
166 when subdirectory entries are modified (i.e., mkdir(2)/
167 rmdir(2)). Subdirectory entry modification events will never be
168 merged with nonsubdirectory entry modification events. This
169 flag is never reported individually within an event and is
170 always supplied in conjunction with another event type.
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. To monitor complete
177 directory trees it is necessary to mark the relevant mount.
178 The following composed values are defined:
180 FAN_CLOSE
182 A file is closed (FAN_CLOSE_WRITE|FAN_CLOSE_NOWRITE).
183 FAN_MOVE
185 A file or directory has been moved
186 (FAN_MOVED_FROM|FAN_MOVED_TO).
187 The filesystem object to be marked is determined by the file descriptor
189 dirfd and the pathname specified in pathname:
190 * If pathname is NULL, dirfd defines the filesystem object to be
192 marked.
193 * If pathname is NULL, and dirfd takes the special value AT_FDCWD, the
195 current working directory is to be marked.
196 * If pathname is absolute, it defines the filesystem object to be
198 marked, and dirfd is ignored.
199 * If pathname is relative, and dirfd does not have the value AT_FDCWD,
201 then the filesystem object to be marked is determined by interpret‐
202 ing pathname relative the directory referred to by dirfd.
203 * If pathname is relative, and dirfd has the value AT_FDCWD, then the
205 filesystem object to be marked is determined by interpreting path‐
206 name relative the current working directory.
207
209 On success, fanotify_mark() returns 0. On error, -1 is returned, and
210 errno is set to indicate the error.
211
213 EBADF An invalid file descriptor was passed in fanotify_fd.
214 EINVAL An invalid value was passed in flags or mask, or fanotify_fd was
216 not an fanotify file descriptor.
217 EINVAL The fanotify file descriptor was opened with FAN_CLASS_NOTIF or
219 FAN_REPORT_FID and mask contains a flag for permission events
220 (FAN_OPEN_PERM or FAN_ACCESS_PERM).
221 ENOENT The filesystem object indicated by dirfd and pathname does not
223 exist. This error also occurs when trying to remove a mark from
224 an object which is not marked.
225 ENOMEM The necessary memory could not be allocated.
227 ENOSPC The number of marks exceeds the limit of 8192 and the FAN_UNLIM‐
229 ITED_MARKS flag was not specified when the fanotify file
230 descriptor was created with fanotify_init(2).
231 ENOSYS This kernel does not implement fanotify_mark(). The fanotify
233 API is available only if the kernel was configured with CON‐
234 FIG_FANOTIFY.
235 ENOTDIR
237 flags contains FAN_MARK_ONLYDIR, and dirfd and pathname do not
238 specify a directory.
239 EXDEV The filesystem object indicated by pathname resides within a
241 filesystem subvolume (e.g., btrfs(5)) which uses a different
242 fsid than its root superblock. This error can be returned only
243 when an fanotify file descriptor returned by fanotify_init(2)
244 has been created with FAN_REPORT_FID.
245 ENODEV The filesystem object indicated by pathname is not associated
247 with a filesystem that supports fsid (e.g., tmpfs(5)). This
248 error can be returned only when an fanotify file descriptor
249 returned by fanotify_init(2) has been created with
250 FAN_REPORT_FID.
251 EOPNOTSUPP
253 The object indicated by pathname is associated with a filesystem
254 that does not support the encoding of file handles. This error
255 can be returned only when an fanotify file descriptor returned
256 by fanotify_init(2) has been created with FAN_REPORT_FID.
257
259 fanotify_mark() was introduced in version 2.6.36 of the Linux kernel
260 and enabled in version 2.6.37.
261
263 This system call is Linux-specific.
264
266 FAN_OPEN_EXEC and FAN_OPEN_EXEC_PERM
267 When using either FAN_OPEN_EXEC or FAN_OPEN_EXEC_PERM within the mask,
268 events of these types will be returned only when the direct execution
269 of a program occurs. More specifically, this means that events of
270 these types will be generated for files that are opened using
271 execve(2), execveat(2), or uselib(2). Events of these types will not
272 be raised in the situation where an interpreter is passed (or reads) a
273 script file for interpretation.
274 Additionally, if a mark has also been placed on the Linux dynamic
276 linker, a user should also expect to receive an event for it when an
277 ELF object has been successfully opened using execve(2) or execveat(2).
278 For example, if the following ELF binary were to be invoked and a
280 FAN_OPEN_EXEC mark has been placed on /:
281 $ /bin/echo foo
283 The listening application in this case would receive FAN_OPEN_EXEC
285 events for both the ELF binary and interpreter, respectively:
286 /bin/echo
288 /lib64/ld-linux-x86-64.so.2
289
291 The following bugs were present in Linux kernels before version 3.16:
292 * If flags contains FAN_MARK_FLUSH, dirfd and pathname must specify a
294 valid filesystem object, even though this object is not used.
295 * readdir(2) does not generate a FAN_ACCESS event.
297 * If fanotify_mark() is called with FAN_MARK_FLUSH, flags is not
299 checked for invalid values.
300
302 fanotify_init(2), fanotify(7)
303
305 This page is part of release 5.02 of the Linux man-pages project. A
306 description of the project, information about reporting bugs, and the
307 latest version of this page, can be found at
308 https://www.kernel.org/doc/man-pages/.
309Linux 2019-08-02 FANOTIFY_MARK(2)