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