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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 | * | |
11 | * This program is free software; you can redistribute it and/or modify it | |
12 | * under the terms of the GNU General Public License as published by the | |
13 | * Free Software Foundation; either version 2, or (at your option) any | |
14 | * later version. | |
15 | * | |
16 | * This program is distributed in the hope that it will be useful, but | |
17 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
19 | * General Public License for more details. | |
20 | */ | |
21 | ||
22 | #include <linux/kernel.h> | |
23 | #include <linux/sched.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/fs.h> | |
26 | #include <linux/file.h> | |
27 | #include <linux/mount.h> | |
28 | #include <linux/namei.h> | |
29 | #include <linux/poll.h> | |
30 | #include <linux/init.h> | |
31 | #include <linux/list.h> | |
32 | #include <linux/inotify.h> | |
33 | #include <linux/syscalls.h> | |
34 | ||
35 | #include <asm/ioctls.h> | |
36 | ||
37 | static kmem_cache_t *watch_cachep __read_mostly; | |
38 | static kmem_cache_t *event_cachep __read_mostly; | |
39 | ||
40 | static struct vfsmount *inotify_mnt __read_mostly; | |
41 | ||
42 | /* these are configurable via /proc/sys/fs/inotify/ */ | |
43 | int inotify_max_user_instances __read_mostly; | |
44 | int inotify_max_user_watches __read_mostly; | |
45 | int inotify_max_queued_events __read_mostly; | |
46 | ||
47 | /* | |
48 | * Lock ordering: | |
49 | * | |
50 | * inotify_dev->up_mutex (ensures we don't re-add the same watch) | |
51 | * inode->inotify_mutex (protects inode's watch list) | |
52 | * inotify_handle->mutex (protects inotify_handle's watch list) | |
53 | * inotify_dev->ev_mutex (protects device's event queue) | |
54 | */ | |
55 | ||
56 | /* | |
57 | * Lifetimes of the main data structures: | |
58 | * | |
59 | * inotify_device: Lifetime is managed by reference count, from | |
60 | * sys_inotify_init() until release. Additional references can bump the count | |
61 | * via get_inotify_dev() and drop the count via put_inotify_dev(). | |
62 | * | |
63 | * inotify_user_watch: Lifetime is from create_watch() to the receipt of an | |
64 | * IN_IGNORED event from inotify, or when using IN_ONESHOT, to receipt of the | |
65 | * first event, or to inotify_destroy(). | |
66 | */ | |
67 | ||
68 | /* | |
69 | * struct inotify_device - represents an inotify instance | |
70 | * | |
71 | * This structure is protected by the mutex 'mutex'. | |
72 | */ | |
73 | struct inotify_device { | |
74 | wait_queue_head_t wq; /* wait queue for i/o */ | |
75 | struct mutex ev_mutex; /* protects event queue */ | |
76 | struct mutex up_mutex; /* synchronizes watch updates */ | |
77 | struct list_head events; /* list of queued events */ | |
78 | atomic_t count; /* reference count */ | |
79 | struct user_struct *user; /* user who opened this dev */ | |
80 | struct inotify_handle *ih; /* inotify handle */ | |
81 | unsigned int queue_size; /* size of the queue (bytes) */ | |
82 | unsigned int event_count; /* number of pending events */ | |
83 | unsigned int max_events; /* maximum number of events */ | |
84 | }; | |
85 | ||
86 | /* | |
87 | * struct inotify_kernel_event - An inotify event, originating from a watch and | |
88 | * queued for user-space. A list of these is attached to each instance of the | |
89 | * device. In read(), this list is walked and all events that can fit in the | |
90 | * buffer are returned. | |
91 | * | |
92 | * Protected by dev->ev_mutex of the device in which we are queued. | |
93 | */ | |
94 | struct inotify_kernel_event { | |
95 | struct inotify_event event; /* the user-space event */ | |
96 | struct list_head list; /* entry in inotify_device's list */ | |
97 | char *name; /* filename, if any */ | |
98 | }; | |
99 | ||
100 | /* | |
101 | * struct inotify_user_watch - our version of an inotify_watch, we add | |
102 | * a reference to the associated inotify_device. | |
103 | */ | |
104 | struct inotify_user_watch { | |
105 | struct inotify_device *dev; /* associated device */ | |
106 | struct inotify_watch wdata; /* inotify watch data */ | |
107 | }; | |
108 | ||
109 | #ifdef CONFIG_SYSCTL | |
110 | ||
111 | #include <linux/sysctl.h> | |
112 | ||
113 | static int zero; | |
114 | ||
115 | ctl_table inotify_table[] = { | |
116 | { | |
117 | .ctl_name = INOTIFY_MAX_USER_INSTANCES, | |
118 | .procname = "max_user_instances", | |
119 | .data = &inotify_max_user_instances, | |
120 | .maxlen = sizeof(int), | |
121 | .mode = 0644, | |
122 | .proc_handler = &proc_dointvec_minmax, | |
123 | .strategy = &sysctl_intvec, | |
124 | .extra1 = &zero, | |
125 | }, | |
126 | { | |
127 | .ctl_name = INOTIFY_MAX_USER_WATCHES, | |
128 | .procname = "max_user_watches", | |
129 | .data = &inotify_max_user_watches, | |
130 | .maxlen = sizeof(int), | |
131 | .mode = 0644, | |
132 | .proc_handler = &proc_dointvec_minmax, | |
133 | .strategy = &sysctl_intvec, | |
134 | .extra1 = &zero, | |
135 | }, | |
136 | { | |
137 | .ctl_name = INOTIFY_MAX_QUEUED_EVENTS, | |
138 | .procname = "max_queued_events", | |
139 | .data = &inotify_max_queued_events, | |
140 | .maxlen = sizeof(int), | |
141 | .mode = 0644, | |
142 | .proc_handler = &proc_dointvec_minmax, | |
143 | .strategy = &sysctl_intvec, | |
144 | .extra1 = &zero | |
145 | }, | |
146 | { .ctl_name = 0 } | |
147 | }; | |
148 | #endif /* CONFIG_SYSCTL */ | |
149 | ||
150 | static inline void get_inotify_dev(struct inotify_device *dev) | |
151 | { | |
152 | atomic_inc(&dev->count); | |
153 | } | |
154 | ||
155 | static inline void put_inotify_dev(struct inotify_device *dev) | |
156 | { | |
157 | if (atomic_dec_and_test(&dev->count)) { | |
158 | atomic_dec(&dev->user->inotify_devs); | |
159 | free_uid(dev->user); | |
160 | kfree(dev); | |
161 | } | |
162 | } | |
163 | ||
164 | /* | |
165 | * free_inotify_user_watch - cleans up the watch and its references | |
166 | */ | |
167 | static void free_inotify_user_watch(struct inotify_watch *w) | |
168 | { | |
169 | struct inotify_user_watch *watch; | |
170 | struct inotify_device *dev; | |
171 | ||
172 | watch = container_of(w, struct inotify_user_watch, wdata); | |
173 | dev = watch->dev; | |
174 | ||
175 | atomic_dec(&dev->user->inotify_watches); | |
176 | put_inotify_dev(dev); | |
177 | kmem_cache_free(watch_cachep, watch); | |
178 | } | |
179 | ||
180 | /* | |
181 | * kernel_event - create a new kernel event with the given parameters | |
182 | * | |
183 | * This function can sleep. | |
184 | */ | |
185 | static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie, | |
186 | const char *name) | |
187 | { | |
188 | struct inotify_kernel_event *kevent; | |
189 | ||
190 | kevent = kmem_cache_alloc(event_cachep, GFP_KERNEL); | |
191 | if (unlikely(!kevent)) | |
192 | return NULL; | |
193 | ||
194 | /* we hand this out to user-space, so zero it just in case */ | |
195 | memset(&kevent->event, 0, sizeof(struct inotify_event)); | |
196 | ||
197 | kevent->event.wd = wd; | |
198 | kevent->event.mask = mask; | |
199 | kevent->event.cookie = cookie; | |
200 | ||
201 | INIT_LIST_HEAD(&kevent->list); | |
202 | ||
203 | if (name) { | |
204 | size_t len, rem, event_size = sizeof(struct inotify_event); | |
205 | ||
206 | /* | |
207 | * We need to pad the filename so as to properly align an | |
208 | * array of inotify_event structures. Because the structure is | |
209 | * small and the common case is a small filename, we just round | |
210 | * up to the next multiple of the structure's sizeof. This is | |
211 | * simple and safe for all architectures. | |
212 | */ | |
213 | len = strlen(name) + 1; | |
214 | rem = event_size - len; | |
215 | if (len > event_size) { | |
216 | rem = event_size - (len % event_size); | |
217 | if (len % event_size == 0) | |
218 | rem = 0; | |
219 | } | |
220 | ||
221 | kevent->name = kmalloc(len + rem, GFP_KERNEL); | |
222 | if (unlikely(!kevent->name)) { | |
223 | kmem_cache_free(event_cachep, kevent); | |
224 | return NULL; | |
225 | } | |
226 | memcpy(kevent->name, name, len); | |
227 | if (rem) | |
228 | memset(kevent->name + len, 0, rem); | |
229 | kevent->event.len = len + rem; | |
230 | } else { | |
231 | kevent->event.len = 0; | |
232 | kevent->name = NULL; | |
233 | } | |
234 | ||
235 | return kevent; | |
236 | } | |
237 | ||
238 | /* | |
239 | * inotify_dev_get_event - return the next event in the given dev's queue | |
240 | * | |
241 | * Caller must hold dev->ev_mutex. | |
242 | */ | |
243 | static inline struct inotify_kernel_event * | |
244 | inotify_dev_get_event(struct inotify_device *dev) | |
245 | { | |
246 | return list_entry(dev->events.next, struct inotify_kernel_event, list); | |
247 | } | |
248 | ||
249 | /* | |
250 | * inotify_dev_queue_event - event handler registered with core inotify, adds | |
251 | * a new event to the given device | |
252 | * | |
253 | * Can sleep (calls kernel_event()). | |
254 | */ | |
255 | static void inotify_dev_queue_event(struct inotify_watch *w, u32 wd, u32 mask, | |
256 | u32 cookie, const char *name) | |
257 | { | |
258 | struct inotify_user_watch *watch; | |
259 | struct inotify_device *dev; | |
260 | struct inotify_kernel_event *kevent, *last; | |
261 | ||
262 | watch = container_of(w, struct inotify_user_watch, wdata); | |
263 | dev = watch->dev; | |
264 | ||
265 | mutex_lock(&dev->ev_mutex); | |
266 | ||
267 | /* we can safely put the watch as we don't reference it while | |
268 | * generating the event | |
269 | */ | |
270 | if (mask & IN_IGNORED || mask & IN_ONESHOT) | |
271 | put_inotify_watch(w); /* final put */ | |
272 | ||
273 | /* coalescing: drop this event if it is a dupe of the previous */ | |
274 | last = inotify_dev_get_event(dev); | |
275 | if (last && last->event.mask == mask && last->event.wd == wd && | |
276 | last->event.cookie == cookie) { | |
277 | const char *lastname = last->name; | |
278 | ||
279 | if (!name && !lastname) | |
280 | goto out; | |
281 | if (name && lastname && !strcmp(lastname, name)) | |
282 | goto out; | |
283 | } | |
284 | ||
285 | /* the queue overflowed and we already sent the Q_OVERFLOW event */ | |
286 | if (unlikely(dev->event_count > dev->max_events)) | |
287 | goto out; | |
288 | ||
289 | /* if the queue overflows, we need to notify user space */ | |
290 | if (unlikely(dev->event_count == dev->max_events)) | |
291 | kevent = kernel_event(-1, IN_Q_OVERFLOW, cookie, NULL); | |
292 | else | |
293 | kevent = kernel_event(wd, mask, cookie, name); | |
294 | ||
295 | if (unlikely(!kevent)) | |
296 | goto out; | |
297 | ||
298 | /* queue the event and wake up anyone waiting */ | |
299 | dev->event_count++; | |
300 | dev->queue_size += sizeof(struct inotify_event) + kevent->event.len; | |
301 | list_add_tail(&kevent->list, &dev->events); | |
302 | wake_up_interruptible(&dev->wq); | |
303 | ||
304 | out: | |
305 | mutex_unlock(&dev->ev_mutex); | |
306 | } | |
307 | ||
308 | /* | |
309 | * remove_kevent - cleans up and ultimately frees the given kevent | |
310 | * | |
311 | * Caller must hold dev->ev_mutex. | |
312 | */ | |
313 | static void remove_kevent(struct inotify_device *dev, | |
314 | struct inotify_kernel_event *kevent) | |
315 | { | |
316 | list_del(&kevent->list); | |
317 | ||
318 | dev->event_count--; | |
319 | dev->queue_size -= sizeof(struct inotify_event) + kevent->event.len; | |
320 | ||
321 | kfree(kevent->name); | |
322 | kmem_cache_free(event_cachep, kevent); | |
323 | } | |
324 | ||
325 | /* | |
326 | * inotify_dev_event_dequeue - destroy an event on the given device | |
327 | * | |
328 | * Caller must hold dev->ev_mutex. | |
329 | */ | |
330 | static void inotify_dev_event_dequeue(struct inotify_device *dev) | |
331 | { | |
332 | if (!list_empty(&dev->events)) { | |
333 | struct inotify_kernel_event *kevent; | |
334 | kevent = inotify_dev_get_event(dev); | |
335 | remove_kevent(dev, kevent); | |
336 | } | |
337 | } | |
338 | ||
339 | /* | |
340 | * find_inode - resolve a user-given path to a specific inode and return a nd | |
341 | */ | |
342 | static int find_inode(const char __user *dirname, struct nameidata *nd, | |
343 | unsigned flags) | |
344 | { | |
345 | int error; | |
346 | ||
347 | error = __user_walk(dirname, flags, nd); | |
348 | if (error) | |
349 | return error; | |
350 | /* you can only watch an inode if you have read permissions on it */ | |
351 | error = vfs_permission(nd, MAY_READ); | |
352 | if (error) | |
353 | path_release(nd); | |
354 | return error; | |
355 | } | |
356 | ||
357 | /* | |
358 | * create_watch - creates a watch on the given device. | |
359 | * | |
360 | * Callers must hold dev->up_mutex. | |
361 | */ | |
362 | static int create_watch(struct inotify_device *dev, struct inode *inode, | |
363 | u32 mask) | |
364 | { | |
365 | struct inotify_user_watch *watch; | |
366 | int ret; | |
367 | ||
368 | if (atomic_read(&dev->user->inotify_watches) >= | |
369 | inotify_max_user_watches) | |
370 | return -ENOSPC; | |
371 | ||
372 | watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL); | |
373 | if (unlikely(!watch)) | |
374 | return -ENOMEM; | |
375 | ||
376 | /* save a reference to device and bump the count to make it official */ | |
377 | get_inotify_dev(dev); | |
378 | watch->dev = dev; | |
379 | ||
380 | atomic_inc(&dev->user->inotify_watches); | |
381 | ||
382 | ret = inotify_add_watch(dev->ih, &watch->wdata, inode, mask); | |
383 | if (ret < 0) | |
384 | free_inotify_user_watch(&watch->wdata); | |
385 | ||
386 | return ret; | |
387 | } | |
388 | ||
389 | /* Device Interface */ | |
390 | ||
391 | static unsigned int inotify_poll(struct file *file, poll_table *wait) | |
392 | { | |
393 | struct inotify_device *dev = file->private_data; | |
394 | int ret = 0; | |
395 | ||
396 | poll_wait(file, &dev->wq, wait); | |
397 | mutex_lock(&dev->ev_mutex); | |
398 | if (!list_empty(&dev->events)) | |
399 | ret = POLLIN | POLLRDNORM; | |
400 | mutex_unlock(&dev->ev_mutex); | |
401 | ||
402 | return ret; | |
403 | } | |
404 | ||
405 | static ssize_t inotify_read(struct file *file, char __user *buf, | |
406 | size_t count, loff_t *pos) | |
407 | { | |
408 | size_t event_size = sizeof (struct inotify_event); | |
409 | struct inotify_device *dev; | |
410 | char __user *start; | |
411 | int ret; | |
412 | DEFINE_WAIT(wait); | |
413 | ||
414 | start = buf; | |
415 | dev = file->private_data; | |
416 | ||
417 | while (1) { | |
418 | int events; | |
419 | ||
420 | prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE); | |
421 | ||
422 | mutex_lock(&dev->ev_mutex); | |
423 | events = !list_empty(&dev->events); | |
424 | mutex_unlock(&dev->ev_mutex); | |
425 | if (events) { | |
426 | ret = 0; | |
427 | break; | |
428 | } | |
429 | ||
430 | if (file->f_flags & O_NONBLOCK) { | |
431 | ret = -EAGAIN; | |
432 | break; | |
433 | } | |
434 | ||
435 | if (signal_pending(current)) { | |
436 | ret = -EINTR; | |
437 | break; | |
438 | } | |
439 | ||
440 | schedule(); | |
441 | } | |
442 | ||
443 | finish_wait(&dev->wq, &wait); | |
444 | if (ret) | |
445 | return ret; | |
446 | ||
447 | mutex_lock(&dev->ev_mutex); | |
448 | while (1) { | |
449 | struct inotify_kernel_event *kevent; | |
450 | ||
451 | ret = buf - start; | |
452 | if (list_empty(&dev->events)) | |
453 | break; | |
454 | ||
455 | kevent = inotify_dev_get_event(dev); | |
456 | if (event_size + kevent->event.len > count) | |
457 | break; | |
458 | ||
459 | if (copy_to_user(buf, &kevent->event, event_size)) { | |
460 | ret = -EFAULT; | |
461 | break; | |
462 | } | |
463 | buf += event_size; | |
464 | count -= event_size; | |
465 | ||
466 | if (kevent->name) { | |
467 | if (copy_to_user(buf, kevent->name, kevent->event.len)){ | |
468 | ret = -EFAULT; | |
469 | break; | |
470 | } | |
471 | buf += kevent->event.len; | |
472 | count -= kevent->event.len; | |
473 | } | |
474 | ||
475 | remove_kevent(dev, kevent); | |
476 | } | |
477 | mutex_unlock(&dev->ev_mutex); | |
478 | ||
479 | return ret; | |
480 | } | |
481 | ||
482 | static int inotify_release(struct inode *ignored, struct file *file) | |
483 | { | |
484 | struct inotify_device *dev = file->private_data; | |
485 | ||
486 | inotify_destroy(dev->ih); | |
487 | ||
488 | /* destroy all of the events on this device */ | |
489 | mutex_lock(&dev->ev_mutex); | |
490 | while (!list_empty(&dev->events)) | |
491 | inotify_dev_event_dequeue(dev); | |
492 | mutex_unlock(&dev->ev_mutex); | |
493 | ||
494 | /* free this device: the put matching the get in inotify_init() */ | |
495 | put_inotify_dev(dev); | |
496 | ||
497 | return 0; | |
498 | } | |
499 | ||
500 | static long inotify_ioctl(struct file *file, unsigned int cmd, | |
501 | unsigned long arg) | |
502 | { | |
503 | struct inotify_device *dev; | |
504 | void __user *p; | |
505 | int ret = -ENOTTY; | |
506 | ||
507 | dev = file->private_data; | |
508 | p = (void __user *) arg; | |
509 | ||
510 | switch (cmd) { | |
511 | case FIONREAD: | |
512 | ret = put_user(dev->queue_size, (int __user *) p); | |
513 | break; | |
514 | } | |
515 | ||
516 | return ret; | |
517 | } | |
518 | ||
519 | static const struct file_operations inotify_fops = { | |
520 | .poll = inotify_poll, | |
521 | .read = inotify_read, | |
522 | .release = inotify_release, | |
523 | .unlocked_ioctl = inotify_ioctl, | |
524 | .compat_ioctl = inotify_ioctl, | |
525 | }; | |
526 | ||
527 | static const struct inotify_operations inotify_user_ops = { | |
528 | .handle_event = inotify_dev_queue_event, | |
529 | .destroy_watch = free_inotify_user_watch, | |
530 | }; | |
531 | ||
532 | asmlinkage long sys_inotify_init(void) | |
533 | { | |
534 | struct inotify_device *dev; | |
535 | struct inotify_handle *ih; | |
536 | struct user_struct *user; | |
537 | struct file *filp; | |
538 | int fd, ret; | |
539 | ||
540 | fd = get_unused_fd(); | |
541 | if (fd < 0) | |
542 | return fd; | |
543 | ||
544 | filp = get_empty_filp(); | |
545 | if (!filp) { | |
546 | ret = -ENFILE; | |
547 | goto out_put_fd; | |
548 | } | |
549 | ||
550 | user = get_uid(current->user); | |
551 | if (unlikely(atomic_read(&user->inotify_devs) >= | |
552 | inotify_max_user_instances)) { | |
553 | ret = -EMFILE; | |
554 | goto out_free_uid; | |
555 | } | |
556 | ||
557 | dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL); | |
558 | if (unlikely(!dev)) { | |
559 | ret = -ENOMEM; | |
560 | goto out_free_uid; | |
561 | } | |
562 | ||
563 | ih = inotify_init(&inotify_user_ops); | |
564 | if (unlikely(IS_ERR(ih))) { | |
565 | ret = PTR_ERR(ih); | |
566 | goto out_free_dev; | |
567 | } | |
568 | dev->ih = ih; | |
569 | ||
570 | filp->f_op = &inotify_fops; | |
571 | filp->f_vfsmnt = mntget(inotify_mnt); | |
572 | filp->f_dentry = dget(inotify_mnt->mnt_root); | |
573 | filp->f_mapping = filp->f_dentry->d_inode->i_mapping; | |
574 | filp->f_mode = FMODE_READ; | |
575 | filp->f_flags = O_RDONLY; | |
576 | filp->private_data = dev; | |
577 | ||
578 | INIT_LIST_HEAD(&dev->events); | |
579 | init_waitqueue_head(&dev->wq); | |
580 | mutex_init(&dev->ev_mutex); | |
581 | mutex_init(&dev->up_mutex); | |
582 | dev->event_count = 0; | |
583 | dev->queue_size = 0; | |
584 | dev->max_events = inotify_max_queued_events; | |
585 | dev->user = user; | |
586 | atomic_set(&dev->count, 0); | |
587 | ||
588 | get_inotify_dev(dev); | |
589 | atomic_inc(&user->inotify_devs); | |
590 | fd_install(fd, filp); | |
591 | ||
592 | return fd; | |
593 | out_free_dev: | |
594 | kfree(dev); | |
595 | out_free_uid: | |
596 | free_uid(user); | |
597 | put_filp(filp); | |
598 | out_put_fd: | |
599 | put_unused_fd(fd); | |
600 | return ret; | |
601 | } | |
602 | ||
603 | asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) | |
604 | { | |
605 | struct inode *inode; | |
606 | struct inotify_device *dev; | |
607 | struct nameidata nd; | |
608 | struct file *filp; | |
609 | int ret, fput_needed; | |
610 | unsigned flags = 0; | |
611 | ||
612 | filp = fget_light(fd, &fput_needed); | |
613 | if (unlikely(!filp)) | |
614 | return -EBADF; | |
615 | ||
616 | /* verify that this is indeed an inotify instance */ | |
617 | if (unlikely(filp->f_op != &inotify_fops)) { | |
618 | ret = -EINVAL; | |
619 | goto fput_and_out; | |
620 | } | |
621 | ||
622 | if (!(mask & IN_DONT_FOLLOW)) | |
623 | flags |= LOOKUP_FOLLOW; | |
624 | if (mask & IN_ONLYDIR) | |
625 | flags |= LOOKUP_DIRECTORY; | |
626 | ||
627 | ret = find_inode(path, &nd, flags); | |
628 | if (unlikely(ret)) | |
629 | goto fput_and_out; | |
630 | ||
631 | /* inode held in place by reference to nd; dev by fget on fd */ | |
632 | inode = nd.dentry->d_inode; | |
633 | dev = filp->private_data; | |
634 | ||
635 | mutex_lock(&dev->up_mutex); | |
636 | ret = inotify_find_update_watch(dev->ih, inode, mask); | |
637 | if (ret == -ENOENT) | |
638 | ret = create_watch(dev, inode, mask); | |
639 | mutex_unlock(&dev->up_mutex); | |
640 | ||
641 | path_release(&nd); | |
642 | fput_and_out: | |
643 | fput_light(filp, fput_needed); | |
644 | return ret; | |
645 | } | |
646 | ||
647 | asmlinkage long sys_inotify_rm_watch(int fd, u32 wd) | |
648 | { | |
649 | struct file *filp; | |
650 | struct inotify_device *dev; | |
651 | int ret, fput_needed; | |
652 | ||
653 | filp = fget_light(fd, &fput_needed); | |
654 | if (unlikely(!filp)) | |
655 | return -EBADF; | |
656 | ||
657 | /* verify that this is indeed an inotify instance */ | |
658 | if (unlikely(filp->f_op != &inotify_fops)) { | |
659 | ret = -EINVAL; | |
660 | goto out; | |
661 | } | |
662 | ||
663 | dev = filp->private_data; | |
664 | ||
665 | /* we free our watch data when we get IN_IGNORED */ | |
666 | ret = inotify_rm_wd(dev->ih, wd); | |
667 | ||
668 | out: | |
669 | fput_light(filp, fput_needed); | |
670 | return ret; | |
671 | } | |
672 | ||
673 | static struct super_block * | |
674 | inotify_get_sb(struct file_system_type *fs_type, int flags, | |
675 | const char *dev_name, void *data) | |
676 | { | |
677 | return get_sb_pseudo(fs_type, "inotify", NULL, 0xBAD1DEA); | |
678 | } | |
679 | ||
680 | static struct file_system_type inotify_fs_type = { | |
681 | .name = "inotifyfs", | |
682 | .get_sb = inotify_get_sb, | |
683 | .kill_sb = kill_anon_super, | |
684 | }; | |
685 | ||
686 | /* | |
687 | * inotify_user_setup - Our initialization function. Note that we cannnot return | |
688 | * error because we have compiled-in VFS hooks. So an (unlikely) failure here | |
689 | * must result in panic(). | |
690 | */ | |
691 | static int __init inotify_user_setup(void) | |
692 | { | |
693 | int ret; | |
694 | ||
695 | ret = register_filesystem(&inotify_fs_type); | |
696 | if (unlikely(ret)) | |
697 | panic("inotify: register_filesystem returned %d!\n", ret); | |
698 | ||
699 | inotify_mnt = kern_mount(&inotify_fs_type); | |
700 | if (IS_ERR(inotify_mnt)) | |
701 | panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt)); | |
702 | ||
703 | inotify_max_queued_events = 16384; | |
704 | inotify_max_user_instances = 128; | |
705 | inotify_max_user_watches = 8192; | |
706 | ||
707 | watch_cachep = kmem_cache_create("inotify_watch_cache", | |
708 | sizeof(struct inotify_user_watch), | |
709 | 0, SLAB_PANIC, NULL, NULL); | |
710 | event_cachep = kmem_cache_create("inotify_event_cache", | |
711 | sizeof(struct inotify_kernel_event), | |
712 | 0, SLAB_PANIC, NULL, NULL); | |
713 | ||
714 | return 0; | |
715 | } | |
716 | ||
717 | module_init(inotify_user_setup); |