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 : static inline int fsnotify_file(struct file *file, __u32 mask)
93 : {
94 0 : const struct path *path = &file->f_path;
95 :
96 0 : if (file->f_mode & FMODE_NONOTIFY)
97 : return 0;
98 :
99 0 : return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
100 : }
101 :
102 : /* Simple call site for access decisions */
103 : static inline int fsnotify_perm(struct file *file, int mask)
104 : {
105 : int ret;
106 : __u32 fsnotify_mask = 0;
107 :
108 : if (!(mask & (MAY_READ | MAY_OPEN)))
109 : return 0;
110 :
111 : if (mask & MAY_OPEN) {
112 : fsnotify_mask = FS_OPEN_PERM;
113 :
114 : if (file->f_flags & __FMODE_EXEC) {
115 : ret = fsnotify_file(file, FS_OPEN_EXEC_PERM);
116 :
117 : if (ret)
118 : return ret;
119 : }
120 : } else if (mask & MAY_READ) {
121 : fsnotify_mask = FS_ACCESS_PERM;
122 : }
123 :
124 : return fsnotify_file(file, fsnotify_mask);
125 : }
126 :
127 : /*
128 : * fsnotify_link_count - inode's link count changed
129 : */
130 : static inline void fsnotify_link_count(struct inode *inode)
131 : {
132 0 : fsnotify_inode(inode, FS_ATTRIB);
133 : }
134 :
135 : /*
136 : * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
137 : */
138 0 : static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
139 : const struct qstr *old_name,
140 : int isdir, struct inode *target,
141 : struct dentry *moved)
142 : {
143 0 : struct inode *source = moved->d_inode;
144 0 : u32 fs_cookie = fsnotify_get_cookie();
145 0 : __u32 old_dir_mask = FS_MOVED_FROM;
146 0 : __u32 new_dir_mask = FS_MOVED_TO;
147 0 : __u32 rename_mask = FS_RENAME;
148 0 : const struct qstr *new_name = &moved->d_name;
149 :
150 0 : if (isdir) {
151 0 : old_dir_mask |= FS_ISDIR;
152 0 : new_dir_mask |= FS_ISDIR;
153 0 : rename_mask |= FS_ISDIR;
154 : }
155 :
156 : /* Event with information about both old and new parent+name */
157 0 : fsnotify_name(rename_mask, moved, FSNOTIFY_EVENT_DENTRY,
158 : old_dir, old_name, 0);
159 :
160 0 : fsnotify_name(old_dir_mask, source, FSNOTIFY_EVENT_INODE,
161 : old_dir, old_name, fs_cookie);
162 0 : fsnotify_name(new_dir_mask, source, FSNOTIFY_EVENT_INODE,
163 : new_dir, new_name, fs_cookie);
164 :
165 0 : if (target)
166 : fsnotify_link_count(target);
167 0 : fsnotify_inode(source, FS_MOVE_SELF);
168 0 : audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
169 0 : }
170 :
171 : /*
172 : * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
173 : */
174 : static inline void fsnotify_inode_delete(struct inode *inode)
175 : {
176 34 : __fsnotify_inode_delete(inode);
177 : }
178 :
179 : /*
180 : * fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
181 : */
182 : static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
183 : {
184 17 : __fsnotify_vfsmount_delete(mnt);
185 : }
186 :
187 : /*
188 : * fsnotify_inoderemove - an inode is going away
189 : */
190 : static inline void fsnotify_inoderemove(struct inode *inode)
191 : {
192 0 : fsnotify_inode(inode, FS_DELETE_SELF);
193 0 : __fsnotify_inode_delete(inode);
194 : }
195 :
196 : /*
197 : * fsnotify_create - 'name' was linked in
198 : *
199 : * Caller must make sure that dentry->d_name is stable.
200 : * Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
201 : * ->d_inode later
202 : */
203 : static inline void fsnotify_create(struct inode *dir, struct dentry *dentry)
204 : {
205 1 : audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
206 :
207 1 : fsnotify_dirent(dir, dentry, FS_CREATE);
208 : }
209 :
210 : /*
211 : * fsnotify_link - new hardlink in 'inode' directory
212 : *
213 : * Caller must make sure that new_dentry->d_name is stable.
214 : * Note: We have to pass also the linked inode ptr as some filesystems leave
215 : * new_dentry->d_inode NULL and instantiate inode pointer later
216 : */
217 0 : static inline void fsnotify_link(struct inode *dir, struct inode *inode,
218 : struct dentry *new_dentry)
219 : {
220 0 : fsnotify_link_count(inode);
221 0 : audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
222 :
223 0 : fsnotify_name(FS_CREATE, inode, FSNOTIFY_EVENT_INODE,
224 0 : dir, &new_dentry->d_name, 0);
225 0 : }
226 :
227 : /*
228 : * fsnotify_delete - @dentry was unlinked and unhashed
229 : *
230 : * Caller must make sure that dentry->d_name is stable.
231 : *
232 : * Note: unlike fsnotify_unlink(), we have to pass also the unlinked inode
233 : * as this may be called after d_delete() and old_dentry may be negative.
234 : */
235 0 : static inline void fsnotify_delete(struct inode *dir, struct inode *inode,
236 : struct dentry *dentry)
237 : {
238 0 : __u32 mask = FS_DELETE;
239 :
240 0 : if (S_ISDIR(inode->i_mode))
241 0 : mask |= FS_ISDIR;
242 :
243 0 : fsnotify_name(mask, inode, FSNOTIFY_EVENT_INODE, dir, &dentry->d_name,
244 : 0);
245 0 : }
246 :
247 : /**
248 : * d_delete_notify - delete a dentry and call fsnotify_delete()
249 : * @dentry: The dentry to delete
250 : *
251 : * This helper is used to guaranty that the unlinked inode cannot be found
252 : * by lookup of this name after fsnotify_delete() event has been delivered.
253 : */
254 0 : static inline void d_delete_notify(struct inode *dir, struct dentry *dentry)
255 : {
256 0 : struct inode *inode = d_inode(dentry);
257 :
258 0 : ihold(inode);
259 0 : d_delete(dentry);
260 0 : fsnotify_delete(dir, inode, dentry);
261 0 : iput(inode);
262 0 : }
263 :
264 : /*
265 : * fsnotify_unlink - 'name' was unlinked
266 : *
267 : * Caller must make sure that dentry->d_name is stable.
268 : */
269 0 : static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
270 : {
271 0 : if (WARN_ON_ONCE(d_is_negative(dentry)))
272 : return;
273 :
274 0 : fsnotify_delete(dir, d_inode(dentry), dentry);
275 : }
276 :
277 : /*
278 : * fsnotify_mkdir - directory 'name' was created
279 : *
280 : * Caller must make sure that dentry->d_name is stable.
281 : * Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
282 : * ->d_inode later
283 : */
284 : static inline void fsnotify_mkdir(struct inode *dir, struct dentry *dentry)
285 : {
286 2 : audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
287 :
288 2 : fsnotify_dirent(dir, dentry, FS_CREATE | FS_ISDIR);
289 : }
290 :
291 : /*
292 : * fsnotify_rmdir - directory 'name' was removed
293 : *
294 : * Caller must make sure that dentry->d_name is stable.
295 : */
296 0 : static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry)
297 : {
298 0 : if (WARN_ON_ONCE(d_is_negative(dentry)))
299 : return;
300 :
301 0 : fsnotify_delete(dir, d_inode(dentry), dentry);
302 : }
303 :
304 : /*
305 : * fsnotify_access - file was read
306 : */
307 : static inline void fsnotify_access(struct file *file)
308 : {
309 0 : fsnotify_file(file, FS_ACCESS);
310 : }
311 :
312 : /*
313 : * fsnotify_modify - file was modified
314 : */
315 : static inline void fsnotify_modify(struct file *file)
316 : {
317 0 : fsnotify_file(file, FS_MODIFY);
318 : }
319 :
320 : /*
321 : * fsnotify_open - file was opened
322 : */
323 0 : static inline void fsnotify_open(struct file *file)
324 : {
325 0 : __u32 mask = FS_OPEN;
326 :
327 0 : if (file->f_flags & __FMODE_EXEC)
328 0 : mask |= FS_OPEN_EXEC;
329 :
330 0 : fsnotify_file(file, mask);
331 0 : }
332 :
333 : /*
334 : * fsnotify_close - file was closed
335 : */
336 0 : static inline void fsnotify_close(struct file *file)
337 : {
338 0 : __u32 mask = (file->f_mode & FMODE_WRITE) ? FS_CLOSE_WRITE :
339 : FS_CLOSE_NOWRITE;
340 :
341 0 : fsnotify_file(file, mask);
342 0 : }
343 :
344 : /*
345 : * fsnotify_xattr - extended attributes were changed
346 : */
347 : static inline void fsnotify_xattr(struct dentry *dentry)
348 : {
349 0 : fsnotify_dentry(dentry, FS_ATTRIB);
350 : }
351 :
352 : /*
353 : * fsnotify_change - notify_change event. file was modified and/or metadata
354 : * was changed.
355 : */
356 0 : static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
357 : {
358 0 : __u32 mask = 0;
359 :
360 0 : if (ia_valid & ATTR_UID)
361 0 : mask |= FS_ATTRIB;
362 0 : if (ia_valid & ATTR_GID)
363 0 : mask |= FS_ATTRIB;
364 0 : if (ia_valid & ATTR_SIZE)
365 0 : mask |= FS_MODIFY;
366 :
367 : /* both times implies a utime(s) call */
368 0 : if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
369 0 : mask |= FS_ATTRIB;
370 0 : else if (ia_valid & ATTR_ATIME)
371 0 : mask |= FS_ACCESS;
372 0 : else if (ia_valid & ATTR_MTIME)
373 0 : mask |= FS_MODIFY;
374 :
375 0 : if (ia_valid & ATTR_MODE)
376 0 : mask |= FS_ATTRIB;
377 :
378 0 : if (mask)
379 : fsnotify_dentry(dentry, mask);
380 0 : }
381 :
382 : static inline int fsnotify_sb_error(struct super_block *sb, struct inode *inode,
383 : int error)
384 : {
385 : struct fs_error_report report = {
386 : .error = error,
387 : .inode = inode,
388 : .sb = sb,
389 : };
390 :
391 : return fsnotify(FS_ERROR, &report, FSNOTIFY_EVENT_ERROR,
392 : NULL, NULL, NULL, 0);
393 : }
394 :
395 : #endif /* _LINUX_FS_NOTIFY_H */
|
