Line data Source code
1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : #ifndef _LINUX_FS_NOTIFY_H
3 : #define _LINUX_FS_NOTIFY_H
4 :
5 : /*
6 : * include/linux/fsnotify.h - generic hooks for filesystem notification, to
7 : * reduce in-source duplication from both dnotify and inotify.
8 : *
9 : * We don't compile any of this away in some complicated menagerie of ifdefs.
10 : * Instead, we rely on the code inside to optimize away as needed.
11 : *
12 : * (C) Copyright 2005 Robert Love
13 : */
14 :
15 : #include <linux/fsnotify_backend.h>
16 : #include <linux/audit.h>
17 : #include <linux/slab.h>
18 : #include <linux/bug.h>
19 :
20 : /*
21 : * Notify this @dir inode about a change in a child directory entry.
22 : * The directory entry may have turned positive or negative or its inode may
23 : * have changed (i.e. renamed over).
24 : *
25 : * Unlike fsnotify_parent(), the event will be reported regardless of the
26 : * FS_EVENT_ON_CHILD mask on the parent inode and will not be reported if only
27 : * the child is interested and not the parent.
28 : */
29 : static inline int fsnotify_name(__u32 mask, const void *data, int data_type,
30 : struct inode *dir, const struct qstr *name,
31 : u32 cookie)
32 : {
33 6 : if (atomic_long_read(&dir->i_sb->s_fsnotify_connectors) == 0)
34 : return 0;
35 :
36 0 : return fsnotify(mask, data, data_type, dir, name, NULL, cookie);
37 : }
38 :
39 3 : static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry,
40 : __u32 mask)
41 : {
42 6 : fsnotify_name(mask, dentry, FSNOTIFY_EVENT_DENTRY, dir, &dentry->d_name, 0);
43 3 : }
44 :
45 0 : static inline void fsnotify_inode(struct inode *inode, __u32 mask)
46 : {
47 0 : if (atomic_long_read(&inode->i_sb->s_fsnotify_connectors) == 0)
48 : return;
49 :
50 0 : if (S_ISDIR(inode->i_mode))
51 0 : mask |= FS_ISDIR;
52 :
53 0 : fsnotify(mask, inode, FSNOTIFY_EVENT_INODE, NULL, NULL, inode, 0);
54 : }
55 :
56 : /* Notify this dentry's parent about a child's events. */
57 0 : static inline int fsnotify_parent(struct dentry *dentry, __u32 mask,
58 : const void *data, int data_type)
59 : {
60 0 : struct inode *inode = d_inode(dentry);
61 :
62 0 : if (atomic_long_read(&inode->i_sb->s_fsnotify_connectors) == 0)
63 : return 0;
64 :
65 0 : if (S_ISDIR(inode->i_mode)) {
66 0 : mask |= FS_ISDIR;
67 :
68 : /* sb/mount marks are not interested in name of directory */
69 0 : if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
70 : goto notify_child;
71 : }
72 :
73 : /* disconnected dentry cannot notify parent */
74 0 : if (IS_ROOT(dentry))
75 : goto notify_child;
76 :
77 0 : return __fsnotify_parent(dentry, mask, data, data_type);
78 :
79 : notify_child:
80 0 : return fsnotify(mask, data, data_type, NULL, NULL, inode, 0);
81 : }
82 :
83 : /*
84 : * Simple wrappers to consolidate calls to fsnotify_parent() when an event
85 : * is on a file/dentry.
86 : */
87 : static inline void fsnotify_dentry(struct dentry *dentry, __u32 mask)
88 : {
89 0 : fsnotify_parent(dentry, mask, dentry, FSNOTIFY_EVENT_DENTRY);
90 : }
91 :
92 0 : static inline int fsnotify_file(struct file *file, __u32 mask)
93 : {
94 : const struct path *path;
95 :
96 0 : if (file->f_mode & FMODE_NONOTIFY)
97 : return 0;
98 :
99 : /* Overlayfs internal files have fake f_path */
100 0 : path = file_real_path(file);
101 0 : return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
102 : }
103 :
104 : /* Simple call site for access decisions */
105 : static inline int fsnotify_perm(struct file *file, int mask)
106 : {
107 : int ret;
108 : __u32 fsnotify_mask = 0;
109 :
110 : if (!(mask & (MAY_READ | MAY_OPEN)))
111 : return 0;
112 :
113 : if (mask & MAY_OPEN) {
114 : fsnotify_mask = FS_OPEN_PERM;
115 :
116 : if (file->f_flags & __FMODE_EXEC) {
117 : ret = fsnotify_file(file, FS_OPEN_EXEC_PERM);
118 :
119 : if (ret)
120 : return ret;
121 : }
122 : } else if (mask & MAY_READ) {
123 : fsnotify_mask = FS_ACCESS_PERM;
124 : }
125 :
126 : return fsnotify_file(file, fsnotify_mask);
127 : }
128 :
129 : /*
130 : * fsnotify_link_count - inode's link count changed
131 : */
132 : static inline void fsnotify_link_count(struct inode *inode)
133 : {
134 0 : fsnotify_inode(inode, FS_ATTRIB);
135 : }
136 :
137 : /*
138 : * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
139 : */
140 0 : static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
141 : const struct qstr *old_name,
142 : int isdir, struct inode *target,
143 : struct dentry *moved)
144 : {
145 0 : struct inode *source = moved->d_inode;
146 0 : u32 fs_cookie = fsnotify_get_cookie();
147 0 : __u32 old_dir_mask = FS_MOVED_FROM;
148 0 : __u32 new_dir_mask = FS_MOVED_TO;
149 0 : __u32 rename_mask = FS_RENAME;
150 0 : const struct qstr *new_name = &moved->d_name;
151 :
152 0 : if (isdir) {
153 0 : old_dir_mask |= FS_ISDIR;
154 0 : new_dir_mask |= FS_ISDIR;
155 0 : rename_mask |= FS_ISDIR;
156 : }
157 :
158 : /* Event with information about both old and new parent+name */
159 0 : fsnotify_name(rename_mask, moved, FSNOTIFY_EVENT_DENTRY,
160 : old_dir, old_name, 0);
161 :
162 0 : fsnotify_name(old_dir_mask, source, FSNOTIFY_EVENT_INODE,
163 : old_dir, old_name, fs_cookie);
164 0 : fsnotify_name(new_dir_mask, source, FSNOTIFY_EVENT_INODE,
165 : new_dir, new_name, fs_cookie);
166 :
167 0 : if (target)
168 : fsnotify_link_count(target);
169 0 : fsnotify_inode(source, FS_MOVE_SELF);
170 0 : audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
171 0 : }
172 :
173 : /*
174 : * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
175 : */
176 : static inline void fsnotify_inode_delete(struct inode *inode)
177 : {
178 10 : __fsnotify_inode_delete(inode);
179 : }
180 :
181 : /*
182 : * fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
183 : */
184 : static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
185 : {
186 5 : __fsnotify_vfsmount_delete(mnt);
187 : }
188 :
189 : /*
190 : * fsnotify_inoderemove - an inode is going away
191 : */
192 : static inline void fsnotify_inoderemove(struct inode *inode)
193 : {
194 0 : fsnotify_inode(inode, FS_DELETE_SELF);
195 0 : __fsnotify_inode_delete(inode);
196 : }
197 :
198 : /*
199 : * fsnotify_create - 'name' was linked in
200 : *
201 : * Caller must make sure that dentry->d_name is stable.
202 : * Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
203 : * ->d_inode later
204 : */
205 : static inline void fsnotify_create(struct inode *dir, struct dentry *dentry)
206 : {
207 1 : audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
208 :
209 1 : fsnotify_dirent(dir, dentry, FS_CREATE);
210 : }
211 :
212 : /*
213 : * fsnotify_link - new hardlink in 'inode' directory
214 : *
215 : * Caller must make sure that new_dentry->d_name is stable.
216 : * Note: We have to pass also the linked inode ptr as some filesystems leave
217 : * new_dentry->d_inode NULL and instantiate inode pointer later
218 : */
219 0 : static inline void fsnotify_link(struct inode *dir, struct inode *inode,
220 : struct dentry *new_dentry)
221 : {
222 0 : fsnotify_link_count(inode);
223 0 : audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
224 :
225 0 : fsnotify_name(FS_CREATE, inode, FSNOTIFY_EVENT_INODE,
226 0 : dir, &new_dentry->d_name, 0);
227 0 : }
228 :
229 : /*
230 : * fsnotify_delete - @dentry was unlinked and unhashed
231 : *
232 : * Caller must make sure that dentry->d_name is stable.
233 : *
234 : * Note: unlike fsnotify_unlink(), we have to pass also the unlinked inode
235 : * as this may be called after d_delete() and old_dentry may be negative.
236 : */
237 0 : static inline void fsnotify_delete(struct inode *dir, struct inode *inode,
238 : struct dentry *dentry)
239 : {
240 0 : __u32 mask = FS_DELETE;
241 :
242 0 : if (S_ISDIR(inode->i_mode))
243 0 : mask |= FS_ISDIR;
244 :
245 0 : fsnotify_name(mask, inode, FSNOTIFY_EVENT_INODE, dir, &dentry->d_name,
246 : 0);
247 0 : }
248 :
249 : /**
250 : * d_delete_notify - delete a dentry and call fsnotify_delete()
251 : * @dentry: The dentry to delete
252 : *
253 : * This helper is used to guaranty that the unlinked inode cannot be found
254 : * by lookup of this name after fsnotify_delete() event has been delivered.
255 : */
256 0 : static inline void d_delete_notify(struct inode *dir, struct dentry *dentry)
257 : {
258 0 : struct inode *inode = d_inode(dentry);
259 :
260 0 : ihold(inode);
261 0 : d_delete(dentry);
262 0 : fsnotify_delete(dir, inode, dentry);
263 0 : iput(inode);
264 0 : }
265 :
266 : /*
267 : * fsnotify_unlink - 'name' was unlinked
268 : *
269 : * Caller must make sure that dentry->d_name is stable.
270 : */
271 0 : static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
272 : {
273 0 : if (WARN_ON_ONCE(d_is_negative(dentry)))
274 : return;
275 :
276 0 : fsnotify_delete(dir, d_inode(dentry), dentry);
277 : }
278 :
279 : /*
280 : * fsnotify_mkdir - directory 'name' was created
281 : *
282 : * Caller must make sure that dentry->d_name is stable.
283 : * Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
284 : * ->d_inode later
285 : */
286 : static inline void fsnotify_mkdir(struct inode *dir, struct dentry *dentry)
287 : {
288 2 : audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
289 :
290 2 : fsnotify_dirent(dir, dentry, FS_CREATE | FS_ISDIR);
291 : }
292 :
293 : /*
294 : * fsnotify_rmdir - directory 'name' was removed
295 : *
296 : * Caller must make sure that dentry->d_name is stable.
297 : */
298 0 : static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry)
299 : {
300 0 : if (WARN_ON_ONCE(d_is_negative(dentry)))
301 : return;
302 :
303 0 : fsnotify_delete(dir, d_inode(dentry), dentry);
304 : }
305 :
306 : /*
307 : * fsnotify_access - file was read
308 : */
309 : static inline void fsnotify_access(struct file *file)
310 : {
311 0 : fsnotify_file(file, FS_ACCESS);
312 : }
313 :
314 : /*
315 : * fsnotify_modify - file was modified
316 : */
317 : static inline void fsnotify_modify(struct file *file)
318 : {
319 0 : fsnotify_file(file, FS_MODIFY);
320 : }
321 :
322 : /*
323 : * fsnotify_open - file was opened
324 : */
325 : static inline void fsnotify_open(struct file *file)
326 : {
327 0 : __u32 mask = FS_OPEN;
328 :
329 0 : if (file->f_flags & __FMODE_EXEC)
330 0 : mask |= FS_OPEN_EXEC;
331 :
332 0 : fsnotify_file(file, mask);
333 : }
334 :
335 : /*
336 : * fsnotify_close - file was closed
337 : */
338 : static inline void fsnotify_close(struct file *file)
339 : {
340 0 : __u32 mask = (file->f_mode & FMODE_WRITE) ? FS_CLOSE_WRITE :
341 : FS_CLOSE_NOWRITE;
342 :
343 0 : fsnotify_file(file, mask);
344 : }
345 :
346 : /*
347 : * fsnotify_xattr - extended attributes were changed
348 : */
349 : static inline void fsnotify_xattr(struct dentry *dentry)
350 : {
351 0 : fsnotify_dentry(dentry, FS_ATTRIB);
352 : }
353 :
354 : /*
355 : * fsnotify_change - notify_change event. file was modified and/or metadata
356 : * was changed.
357 : */
358 0 : static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
359 : {
360 0 : __u32 mask = 0;
361 :
362 0 : if (ia_valid & ATTR_UID)
363 0 : mask |= FS_ATTRIB;
364 0 : if (ia_valid & ATTR_GID)
365 0 : mask |= FS_ATTRIB;
366 0 : if (ia_valid & ATTR_SIZE)
367 0 : mask |= FS_MODIFY;
368 :
369 : /* both times implies a utime(s) call */
370 0 : if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
371 0 : mask |= FS_ATTRIB;
372 0 : else if (ia_valid & ATTR_ATIME)
373 0 : mask |= FS_ACCESS;
374 0 : else if (ia_valid & ATTR_MTIME)
375 0 : mask |= FS_MODIFY;
376 :
377 0 : if (ia_valid & ATTR_MODE)
378 0 : mask |= FS_ATTRIB;
379 :
380 0 : if (mask)
381 : fsnotify_dentry(dentry, mask);
382 0 : }
383 :
384 : static inline int fsnotify_sb_error(struct super_block *sb, struct inode *inode,
385 : int error)
386 : {
387 : struct fs_error_report report = {
388 : .error = error,
389 : .inode = inode,
390 : .sb = sb,
391 : };
392 :
393 : return fsnotify(FS_ERROR, &report, FSNOTIFY_EVENT_ERROR,
394 : NULL, NULL, NULL, 0);
395 : }
396 :
397 : #endif /* _LINUX_FS_NOTIFY_H */
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