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fsnotify.h
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1 #ifndef _LINUX_FS_NOTIFY_H
2 #define _LINUX_FS_NOTIFY_H
3 
4 /*
5  * include/linux/fsnotify.h - generic hooks for filesystem notification, to
6  * reduce in-source duplication from both dnotify and inotify.
7  *
8  * We don't compile any of this away in some complicated menagerie of ifdefs.
9  * Instead, we rely on the code inside to optimize away as needed.
10  *
11  * (C) Copyright 2005 Robert Love
12  */
13 
14 #include <linux/fsnotify_backend.h>
15 #include <linux/audit.h>
16 #include <linux/slab.h>
17 #include <linux/bug.h>
18 
19 /*
20  * fsnotify_d_instantiate - instantiate a dentry for inode
21  */
22 static inline void fsnotify_d_instantiate(struct dentry *dentry,
23  struct inode *inode)
24 {
25  __fsnotify_d_instantiate(dentry, inode);
26 }
27 
28 /* Notify this dentry's parent about a child's events. */
29 static inline int fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
30 {
31  if (!dentry)
32  dentry = path->dentry;
33 
34  return __fsnotify_parent(path, dentry, mask);
35 }
36 
37 /* simple call site for access decisions */
38 static inline int fsnotify_perm(struct file *file, int mask)
39 {
40  struct path *path = &file->f_path;
41  struct inode *inode = path->dentry->d_inode;
42  __u32 fsnotify_mask = 0;
43  int ret;
44 
45  if (file->f_mode & FMODE_NONOTIFY)
46  return 0;
47  if (!(mask & (MAY_READ | MAY_OPEN)))
48  return 0;
49  if (mask & MAY_OPEN)
50  fsnotify_mask = FS_OPEN_PERM;
51  else if (mask & MAY_READ)
52  fsnotify_mask = FS_ACCESS_PERM;
53  else
54  BUG();
55 
56  ret = fsnotify_parent(path, NULL, fsnotify_mask);
57  if (ret)
58  return ret;
59 
60  return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
61 }
62 
63 /*
64  * fsnotify_d_move - dentry has been moved
65  */
66 static inline void fsnotify_d_move(struct dentry *dentry)
67 {
68  /*
69  * On move we need to update dentry->d_flags to indicate if the new parent
70  * cares about events from this dentry.
71  */
72  __fsnotify_update_dcache_flags(dentry);
73 }
74 
75 /*
76  * fsnotify_link_count - inode's link count changed
77  */
78 static inline void fsnotify_link_count(struct inode *inode)
79 {
80  fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
81 }
82 
83 /*
84  * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
85  */
86 static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
87  const unsigned char *old_name,
88  int isdir, struct inode *target, struct dentry *moved)
89 {
90  struct inode *source = moved->d_inode;
91  u32 fs_cookie = fsnotify_get_cookie();
92  __u32 old_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_FROM);
93  __u32 new_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_TO);
94  const unsigned char *new_name = moved->d_name.name;
95 
96  if (old_dir == new_dir)
97  old_dir_mask |= FS_DN_RENAME;
98 
99  if (isdir) {
100  old_dir_mask |= FS_ISDIR;
101  new_dir_mask |= FS_ISDIR;
102  }
103 
104  fsnotify(old_dir, old_dir_mask, old_dir, FSNOTIFY_EVENT_INODE, old_name, fs_cookie);
105  fsnotify(new_dir, new_dir_mask, new_dir, FSNOTIFY_EVENT_INODE, new_name, fs_cookie);
106 
107  if (target)
108  fsnotify_link_count(target);
109 
110  if (source)
111  fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
112  audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
113 }
114 
115 /*
116  * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
117  */
118 static inline void fsnotify_inode_delete(struct inode *inode)
119 {
120  __fsnotify_inode_delete(inode);
121 }
122 
123 /*
124  * fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
125  */
126 static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
127 {
128  __fsnotify_vfsmount_delete(mnt);
129 }
130 
131 /*
132  * fsnotify_nameremove - a filename was removed from a directory
133  */
134 static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
135 {
136  __u32 mask = FS_DELETE;
137 
138  if (isdir)
139  mask |= FS_ISDIR;
140 
141  fsnotify_parent(NULL, dentry, mask);
142 }
143 
144 /*
145  * fsnotify_inoderemove - an inode is going away
146  */
147 static inline void fsnotify_inoderemove(struct inode *inode)
148 {
149  fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
150  __fsnotify_inode_delete(inode);
151 }
152 
153 /*
154  * fsnotify_create - 'name' was linked in
155  */
156 static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
157 {
158  audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
159 
160  fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
161 }
162 
163 /*
164  * fsnotify_link - new hardlink in 'inode' directory
165  * Note: We have to pass also the linked inode ptr as some filesystems leave
166  * new_dentry->d_inode NULL and instantiate inode pointer later
167  */
168 static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
169 {
170  fsnotify_link_count(inode);
171  audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
172 
173  fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, new_dentry->d_name.name, 0);
174 }
175 
176 /*
177  * fsnotify_mkdir - directory 'name' was created
178  */
179 static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
180 {
181  __u32 mask = (FS_CREATE | FS_ISDIR);
182  struct inode *d_inode = dentry->d_inode;
183 
184  audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
185 
186  fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
187 }
188 
189 /*
190  * fsnotify_access - file was read
191  */
192 static inline void fsnotify_access(struct file *file)
193 {
194  struct path *path = &file->f_path;
195  struct inode *inode = path->dentry->d_inode;
196  __u32 mask = FS_ACCESS;
197 
198  if (S_ISDIR(inode->i_mode))
199  mask |= FS_ISDIR;
200 
201  if (!(file->f_mode & FMODE_NONOTIFY)) {
202  fsnotify_parent(path, NULL, mask);
203  fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
204  }
205 }
206 
207 /*
208  * fsnotify_modify - file was modified
209  */
210 static inline void fsnotify_modify(struct file *file)
211 {
212  struct path *path = &file->f_path;
213  struct inode *inode = path->dentry->d_inode;
214  __u32 mask = FS_MODIFY;
215 
216  if (S_ISDIR(inode->i_mode))
217  mask |= FS_ISDIR;
218 
219  if (!(file->f_mode & FMODE_NONOTIFY)) {
220  fsnotify_parent(path, NULL, mask);
221  fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
222  }
223 }
224 
225 /*
226  * fsnotify_open - file was opened
227  */
228 static inline void fsnotify_open(struct file *file)
229 {
230  struct path *path = &file->f_path;
231  struct inode *inode = path->dentry->d_inode;
232  __u32 mask = FS_OPEN;
233 
234  if (S_ISDIR(inode->i_mode))
235  mask |= FS_ISDIR;
236 
237  fsnotify_parent(path, NULL, mask);
238  fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
239 }
240 
241 /*
242  * fsnotify_close - file was closed
243  */
244 static inline void fsnotify_close(struct file *file)
245 {
246  struct path *path = &file->f_path;
247  struct inode *inode = file->f_path.dentry->d_inode;
248  fmode_t mode = file->f_mode;
249  __u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
250 
251  if (S_ISDIR(inode->i_mode))
252  mask |= FS_ISDIR;
253 
254  if (!(file->f_mode & FMODE_NONOTIFY)) {
255  fsnotify_parent(path, NULL, mask);
256  fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
257  }
258 }
259 
260 /*
261  * fsnotify_xattr - extended attributes were changed
262  */
263 static inline void fsnotify_xattr(struct dentry *dentry)
264 {
265  struct inode *inode = dentry->d_inode;
266  __u32 mask = FS_ATTRIB;
267 
268  if (S_ISDIR(inode->i_mode))
269  mask |= FS_ISDIR;
270 
271  fsnotify_parent(NULL, dentry, mask);
272  fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
273 }
274 
275 /*
276  * fsnotify_change - notify_change event. file was modified and/or metadata
277  * was changed.
278  */
279 static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
280 {
281  struct inode *inode = dentry->d_inode;
282  __u32 mask = 0;
283 
284  if (ia_valid & ATTR_UID)
285  mask |= FS_ATTRIB;
286  if (ia_valid & ATTR_GID)
287  mask |= FS_ATTRIB;
288  if (ia_valid & ATTR_SIZE)
289  mask |= FS_MODIFY;
290 
291  /* both times implies a utime(s) call */
292  if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
293  mask |= FS_ATTRIB;
294  else if (ia_valid & ATTR_ATIME)
295  mask |= FS_ACCESS;
296  else if (ia_valid & ATTR_MTIME)
297  mask |= FS_MODIFY;
298 
299  if (ia_valid & ATTR_MODE)
300  mask |= FS_ATTRIB;
301 
302  if (mask) {
303  if (S_ISDIR(inode->i_mode))
304  mask |= FS_ISDIR;
305 
306  fsnotify_parent(NULL, dentry, mask);
307  fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
308  }
309 }
310 
311 #if defined(CONFIG_FSNOTIFY) /* notify helpers */
312 
313 /*
314  * fsnotify_oldname_init - save off the old filename before we change it
315  */
316 static inline const unsigned char *fsnotify_oldname_init(const unsigned char *name)
317 {
318  return kstrdup(name, GFP_KERNEL);
319 }
320 
321 /*
322  * fsnotify_oldname_free - free the name we got from fsnotify_oldname_init
323  */
324 static inline void fsnotify_oldname_free(const unsigned char *old_name)
325 {
326  kfree(old_name);
327 }
328 
329 #else /* CONFIG_FSNOTIFY */
330 
331 static inline const char *fsnotify_oldname_init(const unsigned char *name)
332 {
333  return NULL;
334 }
335 
336 static inline void fsnotify_oldname_free(const unsigned char *old_name)
337 {
338 }
339 
340 #endif /* CONFIG_FSNOTIFY */
341 
342 #endif /* _LINUX_FS_NOTIFY_H */
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