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Commit | Line | Data |
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2d9048e2 AG |
1 | /* |
2 | * fs/inotify_user.c - inotify support for userspace | |
3 | * | |
4 | * Authors: | |
5 | * John McCutchan <ttb@tentacle.dhs.org> | |
6 | * Robert Love <rml@novell.com> | |
7 | * | |
8 | * Copyright (C) 2005 John McCutchan | |
9 | * Copyright 2006 Hewlett-Packard Development Company, L.P. | |
10 | * | |
63c882a0 EP |
11 | * Copyright (C) 2009 Eric Paris <Red Hat Inc> |
12 | * inotify was largely rewriten to make use of the fsnotify infrastructure | |
13 | * | |
2d9048e2 AG |
14 | * This program is free software; you can redistribute it and/or modify it |
15 | * under the terms of the GNU General Public License as published by the | |
16 | * Free Software Foundation; either version 2, or (at your option) any | |
17 | * later version. | |
18 | * | |
19 | * This program is distributed in the hope that it will be useful, but | |
20 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
22 | * General Public License for more details. | |
23 | */ | |
24 | ||
2d9048e2 | 25 | #include <linux/file.h> |
63c882a0 EP |
26 | #include <linux/fs.h> /* struct inode */ |
27 | #include <linux/fsnotify_backend.h> | |
28 | #include <linux/idr.h> | |
29 | #include <linux/init.h> /* module_init */ | |
2d9048e2 | 30 | #include <linux/inotify.h> |
63c882a0 | 31 | #include <linux/kernel.h> /* roundup() */ |
63c882a0 | 32 | #include <linux/namei.h> /* LOOKUP_FOLLOW */ |
63c882a0 EP |
33 | #include <linux/sched.h> /* struct user */ |
34 | #include <linux/slab.h> /* struct kmem_cache */ | |
2d9048e2 | 35 | #include <linux/syscalls.h> |
63c882a0 | 36 | #include <linux/types.h> |
c44dcc56 | 37 | #include <linux/anon_inodes.h> |
63c882a0 EP |
38 | #include <linux/uaccess.h> |
39 | #include <linux/poll.h> | |
40 | #include <linux/wait.h> | |
2d9048e2 | 41 | |
63c882a0 | 42 | #include "inotify.h" |
2d9048e2 | 43 | |
63c882a0 | 44 | #include <asm/ioctls.h> |
2d9048e2 | 45 | |
2d9048e2 | 46 | /* these are configurable via /proc/sys/fs/inotify/ */ |
3c828e49 | 47 | static int inotify_max_user_instances __read_mostly; |
3c828e49 | 48 | static int inotify_max_queued_events __read_mostly; |
0a24887a | 49 | static int inotify_max_user_watches __read_mostly; |
2d9048e2 | 50 | |
63c882a0 EP |
51 | static struct kmem_cache *inotify_inode_mark_cachep __read_mostly; |
52 | struct kmem_cache *event_priv_cachep __read_mostly; | |
2d9048e2 | 53 | |
2d9048e2 AG |
54 | #ifdef CONFIG_SYSCTL |
55 | ||
56 | #include <linux/sysctl.h> | |
57 | ||
58 | static int zero; | |
59 | ||
60 | ctl_table inotify_table[] = { | |
61 | { | |
2d9048e2 AG |
62 | .procname = "max_user_instances", |
63 | .data = &inotify_max_user_instances, | |
64 | .maxlen = sizeof(int), | |
65 | .mode = 0644, | |
6d456111 | 66 | .proc_handler = proc_dointvec_minmax, |
2d9048e2 AG |
67 | .extra1 = &zero, |
68 | }, | |
69 | { | |
2d9048e2 AG |
70 | .procname = "max_user_watches", |
71 | .data = &inotify_max_user_watches, | |
72 | .maxlen = sizeof(int), | |
73 | .mode = 0644, | |
6d456111 | 74 | .proc_handler = proc_dointvec_minmax, |
2d9048e2 AG |
75 | .extra1 = &zero, |
76 | }, | |
77 | { | |
2d9048e2 AG |
78 | .procname = "max_queued_events", |
79 | .data = &inotify_max_queued_events, | |
80 | .maxlen = sizeof(int), | |
81 | .mode = 0644, | |
6d456111 | 82 | .proc_handler = proc_dointvec_minmax, |
2d9048e2 AG |
83 | .extra1 = &zero |
84 | }, | |
ab09203e | 85 | { } |
2d9048e2 AG |
86 | }; |
87 | #endif /* CONFIG_SYSCTL */ | |
88 | ||
63c882a0 | 89 | static inline __u32 inotify_arg_to_mask(u32 arg) |
1c17d18e | 90 | { |
63c882a0 | 91 | __u32 mask; |
1c17d18e | 92 | |
611da04f EP |
93 | /* |
94 | * everything should accept their own ignored, cares about children, | |
95 | * and should receive events when the inode is unmounted | |
96 | */ | |
97 | mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD | FS_UNMOUNT); | |
2d9048e2 | 98 | |
63c882a0 | 99 | /* mask off the flags used to open the fd */ |
8c1934c8 | 100 | mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT | IN_EXCL_UNLINK)); |
2d9048e2 | 101 | |
63c882a0 | 102 | return mask; |
2d9048e2 AG |
103 | } |
104 | ||
63c882a0 | 105 | static inline u32 inotify_mask_to_arg(__u32 mask) |
2d9048e2 | 106 | { |
63c882a0 EP |
107 | return mask & (IN_ALL_EVENTS | IN_ISDIR | IN_UNMOUNT | IN_IGNORED | |
108 | IN_Q_OVERFLOW); | |
2d9048e2 AG |
109 | } |
110 | ||
63c882a0 | 111 | /* intofiy userspace file descriptor functions */ |
2d9048e2 AG |
112 | static unsigned int inotify_poll(struct file *file, poll_table *wait) |
113 | { | |
63c882a0 | 114 | struct fsnotify_group *group = file->private_data; |
2d9048e2 AG |
115 | int ret = 0; |
116 | ||
63c882a0 EP |
117 | poll_wait(file, &group->notification_waitq, wait); |
118 | mutex_lock(&group->notification_mutex); | |
119 | if (!fsnotify_notify_queue_is_empty(group)) | |
2d9048e2 | 120 | ret = POLLIN | POLLRDNORM; |
63c882a0 | 121 | mutex_unlock(&group->notification_mutex); |
2d9048e2 AG |
122 | |
123 | return ret; | |
124 | } | |
125 | ||
3632dee2 VN |
126 | /* |
127 | * Get an inotify_kernel_event if one exists and is small | |
128 | * enough to fit in "count". Return an error pointer if | |
129 | * not large enough. | |
130 | * | |
63c882a0 | 131 | * Called with the group->notification_mutex held. |
3632dee2 | 132 | */ |
63c882a0 EP |
133 | static struct fsnotify_event *get_one_event(struct fsnotify_group *group, |
134 | size_t count) | |
3632dee2 VN |
135 | { |
136 | size_t event_size = sizeof(struct inotify_event); | |
63c882a0 | 137 | struct fsnotify_event *event; |
3632dee2 | 138 | |
63c882a0 | 139 | if (fsnotify_notify_queue_is_empty(group)) |
3632dee2 VN |
140 | return NULL; |
141 | ||
63c882a0 EP |
142 | event = fsnotify_peek_notify_event(group); |
143 | ||
83cb10f0 EP |
144 | if (event->name_len) |
145 | event_size += roundup(event->name_len + 1, event_size); | |
3632dee2 VN |
146 | |
147 | if (event_size > count) | |
148 | return ERR_PTR(-EINVAL); | |
149 | ||
63c882a0 EP |
150 | /* held the notification_mutex the whole time, so this is the |
151 | * same event we peeked above */ | |
152 | fsnotify_remove_notify_event(group); | |
153 | ||
154 | return event; | |
3632dee2 VN |
155 | } |
156 | ||
157 | /* | |
158 | * Copy an event to user space, returning how much we copied. | |
159 | * | |
160 | * We already checked that the event size is smaller than the | |
161 | * buffer we had in "get_one_event()" above. | |
162 | */ | |
63c882a0 EP |
163 | static ssize_t copy_event_to_user(struct fsnotify_group *group, |
164 | struct fsnotify_event *event, | |
3632dee2 VN |
165 | char __user *buf) |
166 | { | |
63c882a0 EP |
167 | struct inotify_event inotify_event; |
168 | struct fsnotify_event_private_data *fsn_priv; | |
169 | struct inotify_event_private_data *priv; | |
3632dee2 | 170 | size_t event_size = sizeof(struct inotify_event); |
b962e731 | 171 | size_t name_len = 0; |
63c882a0 EP |
172 | |
173 | /* we get the inotify watch descriptor from the event private data */ | |
174 | spin_lock(&event->lock); | |
175 | fsn_priv = fsnotify_remove_priv_from_event(group, event); | |
176 | spin_unlock(&event->lock); | |
177 | ||
178 | if (!fsn_priv) | |
179 | inotify_event.wd = -1; | |
180 | else { | |
181 | priv = container_of(fsn_priv, struct inotify_event_private_data, | |
182 | fsnotify_event_priv_data); | |
183 | inotify_event.wd = priv->wd; | |
184 | inotify_free_event_priv(fsn_priv); | |
185 | } | |
186 | ||
b962e731 BR |
187 | /* |
188 | * round up event->name_len so it is a multiple of event_size | |
0db501bd EB |
189 | * plus an extra byte for the terminating '\0'. |
190 | */ | |
b962e731 BR |
191 | if (event->name_len) |
192 | name_len = roundup(event->name_len + 1, event_size); | |
63c882a0 EP |
193 | inotify_event.len = name_len; |
194 | ||
195 | inotify_event.mask = inotify_mask_to_arg(event->mask); | |
196 | inotify_event.cookie = event->sync_cookie; | |
3632dee2 | 197 | |
63c882a0 EP |
198 | /* send the main event */ |
199 | if (copy_to_user(buf, &inotify_event, event_size)) | |
3632dee2 VN |
200 | return -EFAULT; |
201 | ||
63c882a0 | 202 | buf += event_size; |
3632dee2 | 203 | |
63c882a0 EP |
204 | /* |
205 | * fsnotify only stores the pathname, so here we have to send the pathname | |
206 | * and then pad that pathname out to a multiple of sizeof(inotify_event) | |
207 | * with zeros. I get my zeros from the nul_inotify_event. | |
208 | */ | |
209 | if (name_len) { | |
210 | unsigned int len_to_zero = name_len - event->name_len; | |
211 | /* copy the path name */ | |
212 | if (copy_to_user(buf, event->file_name, event->name_len)) | |
3632dee2 | 213 | return -EFAULT; |
63c882a0 | 214 | buf += event->name_len; |
3632dee2 | 215 | |
0db501bd EB |
216 | /* fill userspace with 0's */ |
217 | if (clear_user(buf, len_to_zero)) | |
63c882a0 EP |
218 | return -EFAULT; |
219 | buf += len_to_zero; | |
220 | event_size += name_len; | |
3632dee2 | 221 | } |
63c882a0 | 222 | |
3632dee2 VN |
223 | return event_size; |
224 | } | |
225 | ||
2d9048e2 AG |
226 | static ssize_t inotify_read(struct file *file, char __user *buf, |
227 | size_t count, loff_t *pos) | |
228 | { | |
63c882a0 EP |
229 | struct fsnotify_group *group; |
230 | struct fsnotify_event *kevent; | |
2d9048e2 AG |
231 | char __user *start; |
232 | int ret; | |
233 | DEFINE_WAIT(wait); | |
234 | ||
235 | start = buf; | |
63c882a0 | 236 | group = file->private_data; |
2d9048e2 AG |
237 | |
238 | while (1) { | |
63c882a0 | 239 | prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); |
2d9048e2 | 240 | |
63c882a0 EP |
241 | mutex_lock(&group->notification_mutex); |
242 | kevent = get_one_event(group, count); | |
243 | mutex_unlock(&group->notification_mutex); | |
2d9048e2 | 244 | |
3632dee2 VN |
245 | if (kevent) { |
246 | ret = PTR_ERR(kevent); | |
247 | if (IS_ERR(kevent)) | |
248 | break; | |
63c882a0 EP |
249 | ret = copy_event_to_user(group, kevent, buf); |
250 | fsnotify_put_event(kevent); | |
3632dee2 VN |
251 | if (ret < 0) |
252 | break; | |
253 | buf += ret; | |
254 | count -= ret; | |
255 | continue; | |
2d9048e2 AG |
256 | } |
257 | ||
3632dee2 VN |
258 | ret = -EAGAIN; |
259 | if (file->f_flags & O_NONBLOCK) | |
2d9048e2 | 260 | break; |
3632dee2 VN |
261 | ret = -EINTR; |
262 | if (signal_pending(current)) | |
2d9048e2 | 263 | break; |
16dbc6c9 | 264 | |
3632dee2 | 265 | if (start != buf) |
2d9048e2 | 266 | break; |
16dbc6c9 | 267 | |
3632dee2 | 268 | schedule(); |
2d9048e2 | 269 | } |
2d9048e2 | 270 | |
63c882a0 | 271 | finish_wait(&group->notification_waitq, &wait); |
3632dee2 VN |
272 | if (start != buf && ret != -EFAULT) |
273 | ret = buf - start; | |
2d9048e2 AG |
274 | return ret; |
275 | } | |
276 | ||
bcfbf84d DA |
277 | static int inotify_fasync(int fd, struct file *file, int on) |
278 | { | |
63c882a0 | 279 | struct fsnotify_group *group = file->private_data; |
bcfbf84d | 280 | |
63c882a0 | 281 | return fasync_helper(fd, file, on, &group->inotify_data.fa) >= 0 ? 0 : -EIO; |
bcfbf84d DA |
282 | } |
283 | ||
2d9048e2 AG |
284 | static int inotify_release(struct inode *ignored, struct file *file) |
285 | { | |
63c882a0 | 286 | struct fsnotify_group *group = file->private_data; |
bdae997f | 287 | struct user_struct *user = group->inotify_data.user; |
2d9048e2 | 288 | |
63c882a0 | 289 | fsnotify_clear_marks_by_group(group); |
2d9048e2 | 290 | |
63c882a0 EP |
291 | /* free this group, matching get was inotify_init->fsnotify_obtain_group */ |
292 | fsnotify_put_group(group); | |
2d9048e2 | 293 | |
bdae997f KP |
294 | atomic_dec(&user->inotify_devs); |
295 | ||
2d9048e2 AG |
296 | return 0; |
297 | } | |
298 | ||
299 | static long inotify_ioctl(struct file *file, unsigned int cmd, | |
300 | unsigned long arg) | |
301 | { | |
63c882a0 EP |
302 | struct fsnotify_group *group; |
303 | struct fsnotify_event_holder *holder; | |
304 | struct fsnotify_event *event; | |
2d9048e2 AG |
305 | void __user *p; |
306 | int ret = -ENOTTY; | |
63c882a0 | 307 | size_t send_len = 0; |
2d9048e2 | 308 | |
63c882a0 | 309 | group = file->private_data; |
2d9048e2 AG |
310 | p = (void __user *) arg; |
311 | ||
312 | switch (cmd) { | |
313 | case FIONREAD: | |
63c882a0 EP |
314 | mutex_lock(&group->notification_mutex); |
315 | list_for_each_entry(holder, &group->notification_list, event_list) { | |
316 | event = holder->event; | |
317 | send_len += sizeof(struct inotify_event); | |
83cb10f0 EP |
318 | if (event->name_len) |
319 | send_len += roundup(event->name_len + 1, | |
320 | sizeof(struct inotify_event)); | |
63c882a0 EP |
321 | } |
322 | mutex_unlock(&group->notification_mutex); | |
323 | ret = put_user(send_len, (int __user *) p); | |
2d9048e2 AG |
324 | break; |
325 | } | |
326 | ||
327 | return ret; | |
328 | } | |
329 | ||
330 | static const struct file_operations inotify_fops = { | |
63c882a0 EP |
331 | .poll = inotify_poll, |
332 | .read = inotify_read, | |
333 | .fasync = inotify_fasync, | |
334 | .release = inotify_release, | |
335 | .unlocked_ioctl = inotify_ioctl, | |
2d9048e2 AG |
336 | .compat_ioctl = inotify_ioctl, |
337 | }; | |
338 | ||
2d9048e2 | 339 | |
63c882a0 EP |
340 | /* |
341 | * find_inode - resolve a user-given path to a specific inode | |
342 | */ | |
343 | static int inotify_find_inode(const char __user *dirname, struct path *path, unsigned flags) | |
344 | { | |
345 | int error; | |
346 | ||
347 | error = user_path_at(AT_FDCWD, dirname, flags, path); | |
348 | if (error) | |
349 | return error; | |
350 | /* you can only watch an inode if you have read permissions on it */ | |
351 | error = inode_permission(path->dentry->d_inode, MAY_READ); | |
352 | if (error) | |
353 | path_put(path); | |
354 | return error; | |
355 | } | |
356 | ||
b7ba8371 | 357 | static int inotify_add_to_idr(struct idr *idr, spinlock_t *idr_lock, |
7050c488 | 358 | int *last_wd, |
000285de | 359 | struct inotify_inode_mark *i_mark) |
b7ba8371 EP |
360 | { |
361 | int ret; | |
362 | ||
363 | do { | |
364 | if (unlikely(!idr_pre_get(idr, GFP_KERNEL))) | |
365 | return -ENOMEM; | |
366 | ||
367 | spin_lock(idr_lock); | |
000285de EP |
368 | ret = idr_get_new_above(idr, i_mark, *last_wd + 1, |
369 | &i_mark->wd); | |
b7ba8371 | 370 | /* we added the mark to the idr, take a reference */ |
7050c488 | 371 | if (!ret) { |
000285de EP |
372 | *last_wd = i_mark->wd; |
373 | fsnotify_get_mark(&i_mark->fsn_mark); | |
7050c488 | 374 | } |
b7ba8371 EP |
375 | spin_unlock(idr_lock); |
376 | } while (ret == -EAGAIN); | |
377 | ||
378 | return ret; | |
379 | } | |
380 | ||
000285de | 381 | static struct inotify_inode_mark *inotify_idr_find_locked(struct fsnotify_group *group, |
b7ba8371 EP |
382 | int wd) |
383 | { | |
384 | struct idr *idr = &group->inotify_data.idr; | |
385 | spinlock_t *idr_lock = &group->inotify_data.idr_lock; | |
000285de | 386 | struct inotify_inode_mark *i_mark; |
b7ba8371 EP |
387 | |
388 | assert_spin_locked(idr_lock); | |
389 | ||
000285de EP |
390 | i_mark = idr_find(idr, wd); |
391 | if (i_mark) { | |
392 | struct fsnotify_mark *fsn_mark = &i_mark->fsn_mark; | |
b7ba8371 | 393 | |
000285de | 394 | fsnotify_get_mark(fsn_mark); |
b7ba8371 | 395 | /* One ref for being in the idr, one ref we just took */ |
000285de | 396 | BUG_ON(atomic_read(&fsn_mark->refcnt) < 2); |
b7ba8371 EP |
397 | } |
398 | ||
000285de | 399 | return i_mark; |
b7ba8371 EP |
400 | } |
401 | ||
000285de | 402 | static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group, |
b7ba8371 EP |
403 | int wd) |
404 | { | |
000285de | 405 | struct inotify_inode_mark *i_mark; |
b7ba8371 EP |
406 | spinlock_t *idr_lock = &group->inotify_data.idr_lock; |
407 | ||
408 | spin_lock(idr_lock); | |
000285de | 409 | i_mark = inotify_idr_find_locked(group, wd); |
b7ba8371 EP |
410 | spin_unlock(idr_lock); |
411 | ||
000285de | 412 | return i_mark; |
b7ba8371 EP |
413 | } |
414 | ||
415 | static void do_inotify_remove_from_idr(struct fsnotify_group *group, | |
000285de | 416 | struct inotify_inode_mark *i_mark) |
b7ba8371 EP |
417 | { |
418 | struct idr *idr = &group->inotify_data.idr; | |
419 | spinlock_t *idr_lock = &group->inotify_data.idr_lock; | |
000285de | 420 | int wd = i_mark->wd; |
b7ba8371 EP |
421 | |
422 | assert_spin_locked(idr_lock); | |
423 | ||
424 | idr_remove(idr, wd); | |
425 | ||
426 | /* removed from the idr, drop that ref */ | |
000285de | 427 | fsnotify_put_mark(&i_mark->fsn_mark); |
b7ba8371 EP |
428 | } |
429 | ||
dead537d EP |
430 | /* |
431 | * Remove the mark from the idr (if present) and drop the reference | |
432 | * on the mark because it was in the idr. | |
433 | */ | |
7e790dd5 | 434 | static void inotify_remove_from_idr(struct fsnotify_group *group, |
000285de | 435 | struct inotify_inode_mark *i_mark) |
7e790dd5 | 436 | { |
b7ba8371 | 437 | spinlock_t *idr_lock = &group->inotify_data.idr_lock; |
000285de | 438 | struct inotify_inode_mark *found_i_mark = NULL; |
dead537d | 439 | int wd; |
7e790dd5 | 440 | |
b7ba8371 | 441 | spin_lock(idr_lock); |
000285de | 442 | wd = i_mark->wd; |
dead537d | 443 | |
b7ba8371 | 444 | /* |
000285de | 445 | * does this i_mark think it is in the idr? we shouldn't get called |
b7ba8371 EP |
446 | * if it wasn't.... |
447 | */ | |
448 | if (wd == -1) { | |
000285de EP |
449 | WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" |
450 | " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, | |
451 | i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode); | |
dead537d | 452 | goto out; |
b7ba8371 | 453 | } |
dead537d | 454 | |
b7ba8371 | 455 | /* Lets look in the idr to see if we find it */ |
000285de EP |
456 | found_i_mark = inotify_idr_find_locked(group, wd); |
457 | if (unlikely(!found_i_mark)) { | |
458 | WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" | |
459 | " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, | |
460 | i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode); | |
dead537d | 461 | goto out; |
b7ba8371 | 462 | } |
dead537d | 463 | |
b7ba8371 | 464 | /* |
000285de EP |
465 | * We found an mark in the idr at the right wd, but it's |
466 | * not the mark we were told to remove. eparis seriously | |
b7ba8371 EP |
467 | * fucked up somewhere. |
468 | */ | |
000285de EP |
469 | if (unlikely(found_i_mark != i_mark)) { |
470 | WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p " | |
471 | "mark->inode=%p found_i_mark=%p found_i_mark->wd=%d " | |
472 | "found_i_mark->group=%p found_i_mark->inode=%p\n", | |
473 | __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group, | |
474 | i_mark->fsn_mark.i.inode, found_i_mark, found_i_mark->wd, | |
475 | found_i_mark->fsn_mark.group, | |
476 | found_i_mark->fsn_mark.i.inode); | |
dead537d EP |
477 | goto out; |
478 | } | |
479 | ||
b7ba8371 EP |
480 | /* |
481 | * One ref for being in the idr | |
482 | * one ref held by the caller trying to kill us | |
483 | * one ref grabbed by inotify_idr_find | |
484 | */ | |
000285de EP |
485 | if (unlikely(atomic_read(&i_mark->fsn_mark.refcnt) < 3)) { |
486 | printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" | |
487 | " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, | |
488 | i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode); | |
b7ba8371 EP |
489 | /* we can't really recover with bad ref cnting.. */ |
490 | BUG(); | |
491 | } | |
dead537d | 492 | |
000285de | 493 | do_inotify_remove_from_idr(group, i_mark); |
dead537d | 494 | out: |
b7ba8371 | 495 | /* match the ref taken by inotify_idr_find_locked() */ |
000285de EP |
496 | if (found_i_mark) |
497 | fsnotify_put_mark(&found_i_mark->fsn_mark); | |
498 | i_mark->wd = -1; | |
b7ba8371 | 499 | spin_unlock(idr_lock); |
7e790dd5 | 500 | } |
dead537d | 501 | |
63c882a0 | 502 | /* |
dead537d | 503 | * Send IN_IGNORED for this wd, remove this wd from the idr. |
63c882a0 | 504 | */ |
000285de | 505 | void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, |
528da3e9 | 506 | struct fsnotify_group *group) |
63c882a0 | 507 | { |
000285de | 508 | struct inotify_inode_mark *i_mark; |
f44aebcc | 509 | struct fsnotify_event *ignored_event; |
63c882a0 EP |
510 | struct inotify_event_private_data *event_priv; |
511 | struct fsnotify_event_private_data *fsn_event_priv; | |
eef3a116 | 512 | int ret; |
63c882a0 | 513 | |
f44aebcc EP |
514 | ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL, |
515 | FSNOTIFY_EVENT_NONE, NULL, 0, | |
516 | GFP_NOFS); | |
517 | if (!ignored_event) | |
518 | return; | |
519 | ||
000285de | 520 | i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); |
63c882a0 | 521 | |
f44aebcc | 522 | event_priv = kmem_cache_alloc(event_priv_cachep, GFP_NOFS); |
63c882a0 EP |
523 | if (unlikely(!event_priv)) |
524 | goto skip_send_ignore; | |
525 | ||
526 | fsn_event_priv = &event_priv->fsnotify_event_priv_data; | |
527 | ||
528 | fsn_event_priv->group = group; | |
000285de | 529 | event_priv->wd = i_mark->wd; |
63c882a0 | 530 | |
6e5f77b3 | 531 | ret = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv, NULL, NULL); |
eef3a116 | 532 | if (ret) |
63c882a0 EP |
533 | inotify_free_event_priv(fsn_event_priv); |
534 | ||
535 | skip_send_ignore: | |
536 | ||
f44aebcc EP |
537 | /* matches the reference taken when the event was created */ |
538 | fsnotify_put_event(ignored_event); | |
539 | ||
000285de EP |
540 | /* remove this mark from the idr */ |
541 | inotify_remove_from_idr(group, i_mark); | |
63c882a0 | 542 | |
5549f7cd | 543 | atomic_dec(&group->inotify_data.user->inotify_watches); |
63c882a0 EP |
544 | } |
545 | ||
546 | /* ding dong the mark is dead */ | |
000285de | 547 | static void inotify_free_mark(struct fsnotify_mark *fsn_mark) |
63c882a0 | 548 | { |
000285de | 549 | struct inotify_inode_mark *i_mark; |
31ddd326 | 550 | |
000285de | 551 | i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); |
63c882a0 | 552 | |
000285de | 553 | kmem_cache_free(inotify_inode_mark_cachep, i_mark); |
63c882a0 EP |
554 | } |
555 | ||
52cef755 EP |
556 | static int inotify_update_existing_watch(struct fsnotify_group *group, |
557 | struct inode *inode, | |
558 | u32 arg) | |
63c882a0 | 559 | { |
000285de EP |
560 | struct fsnotify_mark *fsn_mark; |
561 | struct inotify_inode_mark *i_mark; | |
63c882a0 | 562 | __u32 old_mask, new_mask; |
52cef755 EP |
563 | __u32 mask; |
564 | int add = (arg & IN_MASK_ADD); | |
565 | int ret; | |
63c882a0 EP |
566 | |
567 | /* don't allow invalid bits: we don't want flags set */ | |
568 | mask = inotify_arg_to_mask(arg); | |
569 | if (unlikely(!mask)) | |
570 | return -EINVAL; | |
571 | ||
5444e298 | 572 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
000285de | 573 | if (!fsn_mark) |
52cef755 | 574 | return -ENOENT; |
7e790dd5 | 575 | |
000285de | 576 | i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); |
75fe2b26 | 577 | |
000285de | 578 | spin_lock(&fsn_mark->lock); |
63c882a0 | 579 | |
000285de | 580 | old_mask = fsn_mark->mask; |
90b1e7a5 EP |
581 | if (add) |
582 | fsnotify_set_mark_mask_locked(fsn_mark, (fsn_mark->mask | mask)); | |
583 | else | |
584 | fsnotify_set_mark_mask_locked(fsn_mark, mask); | |
585 | new_mask = fsn_mark->mask; | |
63c882a0 | 586 | |
000285de | 587 | spin_unlock(&fsn_mark->lock); |
63c882a0 EP |
588 | |
589 | if (old_mask != new_mask) { | |
590 | /* more bits in old than in new? */ | |
591 | int dropped = (old_mask & ~new_mask); | |
000285de | 592 | /* more bits in this fsn_mark than the inode's mask? */ |
63c882a0 | 593 | int do_inode = (new_mask & ~inode->i_fsnotify_mask); |
000285de | 594 | /* more bits in this fsn_mark than the group? */ |
63c882a0 EP |
595 | int do_group = (new_mask & ~group->mask); |
596 | ||
000285de | 597 | /* update the inode with this new fsn_mark */ |
63c882a0 EP |
598 | if (dropped || do_inode) |
599 | fsnotify_recalc_inode_mask(inode); | |
600 | ||
601 | /* update the group mask with the new mask */ | |
602 | if (dropped || do_group) | |
603 | fsnotify_recalc_group_mask(group); | |
604 | } | |
605 | ||
52cef755 | 606 | /* return the wd */ |
000285de | 607 | ret = i_mark->wd; |
52cef755 | 608 | |
d0775441 | 609 | /* match the get from fsnotify_find_mark() */ |
000285de | 610 | fsnotify_put_mark(fsn_mark); |
75fe2b26 | 611 | |
52cef755 EP |
612 | return ret; |
613 | } | |
614 | ||
615 | static int inotify_new_watch(struct fsnotify_group *group, | |
616 | struct inode *inode, | |
617 | u32 arg) | |
618 | { | |
000285de | 619 | struct inotify_inode_mark *tmp_i_mark; |
52cef755 EP |
620 | __u32 mask; |
621 | int ret; | |
b7ba8371 EP |
622 | struct idr *idr = &group->inotify_data.idr; |
623 | spinlock_t *idr_lock = &group->inotify_data.idr_lock; | |
52cef755 EP |
624 | |
625 | /* don't allow invalid bits: we don't want flags set */ | |
626 | mask = inotify_arg_to_mask(arg); | |
627 | if (unlikely(!mask)) | |
628 | return -EINVAL; | |
629 | ||
000285de EP |
630 | tmp_i_mark = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); |
631 | if (unlikely(!tmp_i_mark)) | |
52cef755 EP |
632 | return -ENOMEM; |
633 | ||
000285de EP |
634 | fsnotify_init_mark(&tmp_i_mark->fsn_mark, inotify_free_mark); |
635 | tmp_i_mark->fsn_mark.mask = mask; | |
636 | tmp_i_mark->wd = -1; | |
52cef755 EP |
637 | |
638 | ret = -ENOSPC; | |
639 | if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) | |
640 | goto out_err; | |
e0873344 | 641 | |
7050c488 | 642 | ret = inotify_add_to_idr(idr, idr_lock, &group->inotify_data.last_wd, |
000285de | 643 | tmp_i_mark); |
b7ba8371 | 644 | if (ret) |
52cef755 | 645 | goto out_err; |
52cef755 EP |
646 | |
647 | /* we are on the idr, now get on the inode */ | |
5444e298 | 648 | ret = fsnotify_add_mark(&tmp_i_mark->fsn_mark, group, inode, NULL, 0); |
52cef755 EP |
649 | if (ret) { |
650 | /* we failed to get on the inode, get off the idr */ | |
000285de | 651 | inotify_remove_from_idr(group, tmp_i_mark); |
52cef755 EP |
652 | goto out_err; |
653 | } | |
654 | ||
52cef755 EP |
655 | /* increment the number of watches the user has */ |
656 | atomic_inc(&group->inotify_data.user->inotify_watches); | |
657 | ||
000285de EP |
658 | /* return the watch descriptor for this new mark */ |
659 | ret = tmp_i_mark->wd; | |
52cef755 | 660 | |
750a8870 EP |
661 | /* if this mark added a new event update the group mask */ |
662 | if (mask & ~group->mask) | |
663 | fsnotify_recalc_group_mask(group); | |
664 | ||
63c882a0 | 665 | out_err: |
000285de EP |
666 | /* match the ref from fsnotify_init_mark() */ |
667 | fsnotify_put_mark(&tmp_i_mark->fsn_mark); | |
52cef755 EP |
668 | |
669 | return ret; | |
670 | } | |
671 | ||
672 | static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) | |
673 | { | |
674 | int ret = 0; | |
675 | ||
676 | retry: | |
677 | /* try to update and existing watch with the new arg */ | |
678 | ret = inotify_update_existing_watch(group, inode, arg); | |
679 | /* no mark present, try to add a new one */ | |
680 | if (ret == -ENOENT) | |
681 | ret = inotify_new_watch(group, inode, arg); | |
682 | /* | |
683 | * inotify_new_watch could race with another thread which did an | |
684 | * inotify_new_watch between the update_existing and the add watch | |
685 | * here, go back and try to update an existing mark again. | |
686 | */ | |
687 | if (ret == -EEXIST) | |
688 | goto retry; | |
7e790dd5 | 689 | |
63c882a0 EP |
690 | return ret; |
691 | } | |
692 | ||
693 | static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsigned int max_events) | |
694 | { | |
695 | struct fsnotify_group *group; | |
63c882a0 | 696 | |
0d2e2a1d | 697 | group = fsnotify_alloc_group(&inotify_fsnotify_ops); |
63c882a0 EP |
698 | if (IS_ERR(group)) |
699 | return group; | |
700 | ||
701 | group->max_events = max_events; | |
702 | ||
703 | spin_lock_init(&group->inotify_data.idr_lock); | |
704 | idr_init(&group->inotify_data.idr); | |
9e572cc9 | 705 | group->inotify_data.last_wd = 0; |
63c882a0 EP |
706 | group->inotify_data.user = user; |
707 | group->inotify_data.fa = NULL; | |
708 | ||
709 | return group; | |
710 | } | |
711 | ||
712 | ||
713 | /* inotify syscalls */ | |
938bb9f5 | 714 | SYSCALL_DEFINE1(inotify_init1, int, flags) |
2d9048e2 | 715 | { |
63c882a0 | 716 | struct fsnotify_group *group; |
2d9048e2 | 717 | struct user_struct *user; |
c44dcc56 | 718 | int ret; |
2d9048e2 | 719 | |
e38b36f3 UD |
720 | /* Check the IN_* constants for consistency. */ |
721 | BUILD_BUG_ON(IN_CLOEXEC != O_CLOEXEC); | |
722 | BUILD_BUG_ON(IN_NONBLOCK != O_NONBLOCK); | |
723 | ||
510df2dd | 724 | if (flags & ~(IN_CLOEXEC | IN_NONBLOCK)) |
4006553b UD |
725 | return -EINVAL; |
726 | ||
da9592ed | 727 | user = get_current_user(); |
2d9048e2 AG |
728 | if (unlikely(atomic_read(&user->inotify_devs) >= |
729 | inotify_max_user_instances)) { | |
730 | ret = -EMFILE; | |
731 | goto out_free_uid; | |
732 | } | |
733 | ||
63c882a0 EP |
734 | /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ |
735 | group = inotify_new_group(user, inotify_max_queued_events); | |
736 | if (IS_ERR(group)) { | |
737 | ret = PTR_ERR(group); | |
2d9048e2 AG |
738 | goto out_free_uid; |
739 | } | |
740 | ||
825f9692 AV |
741 | atomic_inc(&user->inotify_devs); |
742 | ||
c44dcc56 AV |
743 | ret = anon_inode_getfd("inotify", &inotify_fops, group, |
744 | O_RDONLY | flags); | |
745 | if (ret >= 0) | |
746 | return ret; | |
825f9692 | 747 | |
825f9692 | 748 | atomic_dec(&user->inotify_devs); |
2d9048e2 AG |
749 | out_free_uid: |
750 | free_uid(user); | |
2d9048e2 AG |
751 | return ret; |
752 | } | |
753 | ||
938bb9f5 | 754 | SYSCALL_DEFINE0(inotify_init) |
4006553b UD |
755 | { |
756 | return sys_inotify_init1(0); | |
757 | } | |
758 | ||
2e4d0924 HC |
759 | SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname, |
760 | u32, mask) | |
2d9048e2 | 761 | { |
63c882a0 | 762 | struct fsnotify_group *group; |
2d9048e2 | 763 | struct inode *inode; |
2d8f3038 | 764 | struct path path; |
2d9048e2 AG |
765 | struct file *filp; |
766 | int ret, fput_needed; | |
767 | unsigned flags = 0; | |
768 | ||
769 | filp = fget_light(fd, &fput_needed); | |
770 | if (unlikely(!filp)) | |
771 | return -EBADF; | |
772 | ||
773 | /* verify that this is indeed an inotify instance */ | |
774 | if (unlikely(filp->f_op != &inotify_fops)) { | |
775 | ret = -EINVAL; | |
776 | goto fput_and_out; | |
777 | } | |
778 | ||
779 | if (!(mask & IN_DONT_FOLLOW)) | |
780 | flags |= LOOKUP_FOLLOW; | |
781 | if (mask & IN_ONLYDIR) | |
782 | flags |= LOOKUP_DIRECTORY; | |
783 | ||
63c882a0 EP |
784 | ret = inotify_find_inode(pathname, &path, flags); |
785 | if (ret) | |
2d9048e2 AG |
786 | goto fput_and_out; |
787 | ||
63c882a0 | 788 | /* inode held in place by reference to path; group by fget on fd */ |
2d8f3038 | 789 | inode = path.dentry->d_inode; |
63c882a0 | 790 | group = filp->private_data; |
2d9048e2 | 791 | |
63c882a0 EP |
792 | /* create/update an inode mark */ |
793 | ret = inotify_update_watch(group, inode, mask); | |
2d8f3038 | 794 | path_put(&path); |
2d9048e2 AG |
795 | fput_and_out: |
796 | fput_light(filp, fput_needed); | |
797 | return ret; | |
798 | } | |
799 | ||
2e4d0924 | 800 | SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) |
2d9048e2 | 801 | { |
63c882a0 | 802 | struct fsnotify_group *group; |
000285de | 803 | struct inotify_inode_mark *i_mark; |
2d9048e2 | 804 | struct file *filp; |
63c882a0 | 805 | int ret = 0, fput_needed; |
2d9048e2 AG |
806 | |
807 | filp = fget_light(fd, &fput_needed); | |
808 | if (unlikely(!filp)) | |
809 | return -EBADF; | |
810 | ||
811 | /* verify that this is indeed an inotify instance */ | |
b7ba8371 EP |
812 | ret = -EINVAL; |
813 | if (unlikely(filp->f_op != &inotify_fops)) | |
2d9048e2 | 814 | goto out; |
2d9048e2 | 815 | |
63c882a0 | 816 | group = filp->private_data; |
2d9048e2 | 817 | |
b7ba8371 | 818 | ret = -EINVAL; |
000285de EP |
819 | i_mark = inotify_idr_find(group, wd); |
820 | if (unlikely(!i_mark)) | |
63c882a0 | 821 | goto out; |
63c882a0 | 822 | |
b7ba8371 EP |
823 | ret = 0; |
824 | ||
000285de | 825 | fsnotify_destroy_mark(&i_mark->fsn_mark); |
b7ba8371 EP |
826 | |
827 | /* match ref taken by inotify_idr_find */ | |
000285de | 828 | fsnotify_put_mark(&i_mark->fsn_mark); |
2d9048e2 AG |
829 | |
830 | out: | |
831 | fput_light(filp, fput_needed); | |
832 | return ret; | |
833 | } | |
834 | ||
2d9048e2 AG |
835 | /* |
836 | * inotify_user_setup - Our initialization function. Note that we cannnot return | |
837 | * error because we have compiled-in VFS hooks. So an (unlikely) failure here | |
838 | * must result in panic(). | |
839 | */ | |
840 | static int __init inotify_user_setup(void) | |
841 | { | |
f874e1ac EP |
842 | BUILD_BUG_ON(IN_ACCESS != FS_ACCESS); |
843 | BUILD_BUG_ON(IN_MODIFY != FS_MODIFY); | |
844 | BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB); | |
845 | BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE); | |
846 | BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); | |
847 | BUILD_BUG_ON(IN_OPEN != FS_OPEN); | |
848 | BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM); | |
849 | BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO); | |
850 | BUILD_BUG_ON(IN_CREATE != FS_CREATE); | |
851 | BUILD_BUG_ON(IN_DELETE != FS_DELETE); | |
852 | BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF); | |
853 | BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF); | |
854 | BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT); | |
855 | BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW); | |
856 | BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED); | |
857 | BUILD_BUG_ON(IN_EXCL_UNLINK != FS_EXCL_UNLINK); | |
858 | BUILD_BUG_ON(IN_ISDIR != FS_IN_ISDIR); | |
859 | BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT); | |
860 | ||
861 | BUG_ON(hweight32(ALL_INOTIFY_BITS) != 21); | |
862 | ||
000285de | 863 | inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC); |
63c882a0 | 864 | event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC); |
63c882a0 | 865 | |
2d9048e2 AG |
866 | inotify_max_queued_events = 16384; |
867 | inotify_max_user_instances = 128; | |
868 | inotify_max_user_watches = 8192; | |
869 | ||
2d9048e2 AG |
870 | return 0; |
871 | } | |
2d9048e2 | 872 | module_init(inotify_user_setup); |