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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 */
29static 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(&dir->i_sb->s_fsnotify_connectors) == 0)
34 return 0;
35
36 return fsnotify(mask, data, data_type, dir, name, NULL, cookie);
37}
38
39static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry,
40 __u32 mask)
41{
42 fsnotify_name(mask, dentry, FSNOTIFY_EVENT_DENTRY, dir, &dentry->d_name, 0);
43}
44
45static inline void fsnotify_inode(struct inode *inode, __u32 mask)
46{
47 if (atomic_long_read(&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, inode, FSNOTIFY_EVENT_INODE, NULL, NULL, inode, 0);
54}
55
56/* Notify this dentry's parent about a child's events. */
57static 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(&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
79notify_child:
80 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 */
87static inline void fsnotify_dentry(struct dentry *dentry, __u32 mask)
88{
89 fsnotify_parent(dentry, mask, dentry, FSNOTIFY_EVENT_DENTRY);
90}
91
92static 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(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
101}
102
103/* Simple call site for access decisions */
104static 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, fsnotify_mask);
126}
127
128/*
129 * fsnotify_link_count - inode's link count changed
130 */
131static 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 */
139static 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(rename_mask, moved, FSNOTIFY_EVENT_DENTRY,
159 old_dir, old_name, 0);
160
161 fsnotify_name(old_dir_mask, source, FSNOTIFY_EVENT_INODE,
162 old_dir, old_name, fs_cookie);
163 fsnotify_name(new_dir_mask, source, FSNOTIFY_EVENT_INODE,
164 new_dir, new_name, fs_cookie);
165
166 if (target)
167 fsnotify_link_count(target);
168 fsnotify_inode(source, FS_MOVE_SELF);
169 audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
170}
171
172/*
173 * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
174 */
175static 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 */
183static 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 */
191static 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 */
204static inline void fsnotify_create(struct inode *dir, struct dentry *dentry)
205{
206 audit_inode_child(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 */
218static 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(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
223
224 fsnotify_name(FS_CREATE, inode, FSNOTIFY_EVENT_INODE,
225 dir, &new_dentry->d_name, 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 */
236static 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, inode, FSNOTIFY_EVENT_INODE, dir, &dentry->d_name,
245 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 */
255static 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 */
270static 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, 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 */
285static inline void fsnotify_mkdir(struct inode *dir, struct dentry *dentry)
286{
287 audit_inode_child(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 */
297static 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, d_inode(dentry), dentry);
303}
304
305/*
306 * fsnotify_access - file was read
307 */
308static inline void fsnotify_access(struct file *file)
309{
310 fsnotify_file(file, FS_ACCESS);
311}
312
313/*
314 * fsnotify_modify - file was modified
315 */
316static inline void fsnotify_modify(struct file *file)
317{
318 fsnotify_file(file, FS_MODIFY);
319}
320
321/*
322 * fsnotify_open - file was opened
323 */
324static 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 */
337static 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 */
348static 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 */
357static 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
383static 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, &report, FSNOTIFY_EVENT_ERROR,
393 NULL, NULL, NULL, 0);
394}
395
396#endif /* _LINUX_FS_NOTIFY_H */