blob: d85c7d931cdfd4cb4cfa5bc839b08b4de22f9bb1 [file] [log] [blame]
Amy Griffis2d9048e2006-06-01 13:10:59 -07001/*
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>
Andrey Mirkinfd5eea42007-10-16 23:30:13 -070034#include <linux/magic.h>
Amy Griffis2d9048e2006-06-01 13:10:59 -070035
36#include <asm/ioctls.h>
37
Christoph Lametere18b8902006-12-06 20:33:20 -080038static struct kmem_cache *watch_cachep __read_mostly;
39static struct kmem_cache *event_cachep __read_mostly;
Amy Griffis2d9048e2006-06-01 13:10:59 -070040
41static struct vfsmount *inotify_mnt __read_mostly;
42
43/* these are configurable via /proc/sys/fs/inotify/ */
Harvey Harrison3c828e42008-02-14 19:31:21 -080044static int inotify_max_user_instances __read_mostly;
45static int inotify_max_user_watches __read_mostly;
46static int inotify_max_queued_events __read_mostly;
Amy Griffis2d9048e2006-06-01 13:10:59 -070047
48/*
49 * Lock ordering:
50 *
51 * inotify_dev->up_mutex (ensures we don't re-add the same watch)
52 * inode->inotify_mutex (protects inode's watch list)
53 * inotify_handle->mutex (protects inotify_handle's watch list)
54 * inotify_dev->ev_mutex (protects device's event queue)
55 */
56
57/*
58 * Lifetimes of the main data structures:
59 *
60 * inotify_device: Lifetime is managed by reference count, from
61 * sys_inotify_init() until release. Additional references can bump the count
62 * via get_inotify_dev() and drop the count via put_inotify_dev().
63 *
64 * inotify_user_watch: Lifetime is from create_watch() to the receipt of an
65 * IN_IGNORED event from inotify, or when using IN_ONESHOT, to receipt of the
66 * first event, or to inotify_destroy().
67 */
68
69/*
70 * struct inotify_device - represents an inotify instance
71 *
72 * This structure is protected by the mutex 'mutex'.
73 */
74struct inotify_device {
75 wait_queue_head_t wq; /* wait queue for i/o */
76 struct mutex ev_mutex; /* protects event queue */
77 struct mutex up_mutex; /* synchronizes watch updates */
78 struct list_head events; /* list of queued events */
79 atomic_t count; /* reference count */
80 struct user_struct *user; /* user who opened this dev */
81 struct inotify_handle *ih; /* inotify handle */
Dmitry Antipovbcfbf842008-02-06 01:36:19 -080082 struct fasync_struct *fa; /* async notification */
Amy Griffis2d9048e2006-06-01 13:10:59 -070083 unsigned int queue_size; /* size of the queue (bytes) */
84 unsigned int event_count; /* number of pending events */
85 unsigned int max_events; /* maximum number of events */
86};
87
88/*
89 * struct inotify_kernel_event - An inotify event, originating from a watch and
90 * queued for user-space. A list of these is attached to each instance of the
91 * device. In read(), this list is walked and all events that can fit in the
92 * buffer are returned.
93 *
94 * Protected by dev->ev_mutex of the device in which we are queued.
95 */
96struct inotify_kernel_event {
97 struct inotify_event event; /* the user-space event */
98 struct list_head list; /* entry in inotify_device's list */
99 char *name; /* filename, if any */
100};
101
102/*
103 * struct inotify_user_watch - our version of an inotify_watch, we add
104 * a reference to the associated inotify_device.
105 */
106struct inotify_user_watch {
107 struct inotify_device *dev; /* associated device */
108 struct inotify_watch wdata; /* inotify watch data */
109};
110
111#ifdef CONFIG_SYSCTL
112
113#include <linux/sysctl.h>
114
115static int zero;
116
117ctl_table inotify_table[] = {
118 {
119 .ctl_name = INOTIFY_MAX_USER_INSTANCES,
120 .procname = "max_user_instances",
121 .data = &inotify_max_user_instances,
122 .maxlen = sizeof(int),
123 .mode = 0644,
124 .proc_handler = &proc_dointvec_minmax,
125 .strategy = &sysctl_intvec,
126 .extra1 = &zero,
127 },
128 {
129 .ctl_name = INOTIFY_MAX_USER_WATCHES,
130 .procname = "max_user_watches",
131 .data = &inotify_max_user_watches,
132 .maxlen = sizeof(int),
133 .mode = 0644,
134 .proc_handler = &proc_dointvec_minmax,
135 .strategy = &sysctl_intvec,
136 .extra1 = &zero,
137 },
138 {
139 .ctl_name = INOTIFY_MAX_QUEUED_EVENTS,
140 .procname = "max_queued_events",
141 .data = &inotify_max_queued_events,
142 .maxlen = sizeof(int),
143 .mode = 0644,
144 .proc_handler = &proc_dointvec_minmax,
145 .strategy = &sysctl_intvec,
146 .extra1 = &zero
147 },
148 { .ctl_name = 0 }
149};
150#endif /* CONFIG_SYSCTL */
151
152static inline void get_inotify_dev(struct inotify_device *dev)
153{
154 atomic_inc(&dev->count);
155}
156
157static inline void put_inotify_dev(struct inotify_device *dev)
158{
159 if (atomic_dec_and_test(&dev->count)) {
160 atomic_dec(&dev->user->inotify_devs);
161 free_uid(dev->user);
162 kfree(dev);
163 }
164}
165
166/*
167 * free_inotify_user_watch - cleans up the watch and its references
168 */
169static void free_inotify_user_watch(struct inotify_watch *w)
170{
171 struct inotify_user_watch *watch;
172 struct inotify_device *dev;
173
174 watch = container_of(w, struct inotify_user_watch, wdata);
175 dev = watch->dev;
176
177 atomic_dec(&dev->user->inotify_watches);
178 put_inotify_dev(dev);
179 kmem_cache_free(watch_cachep, watch);
180}
181
182/*
183 * kernel_event - create a new kernel event with the given parameters
184 *
185 * This function can sleep.
186 */
187static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
188 const char *name)
189{
190 struct inotify_kernel_event *kevent;
191
Arjan van de Ven5b6509a2006-07-30 03:03:54 -0700192 kevent = kmem_cache_alloc(event_cachep, GFP_NOFS);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700193 if (unlikely(!kevent))
194 return NULL;
195
196 /* we hand this out to user-space, so zero it just in case */
197 memset(&kevent->event, 0, sizeof(struct inotify_event));
198
199 kevent->event.wd = wd;
200 kevent->event.mask = mask;
201 kevent->event.cookie = cookie;
202
203 INIT_LIST_HEAD(&kevent->list);
204
205 if (name) {
206 size_t len, rem, event_size = sizeof(struct inotify_event);
207
208 /*
209 * We need to pad the filename so as to properly align an
210 * array of inotify_event structures. Because the structure is
211 * small and the common case is a small filename, we just round
212 * up to the next multiple of the structure's sizeof. This is
213 * simple and safe for all architectures.
214 */
215 len = strlen(name) + 1;
216 rem = event_size - len;
217 if (len > event_size) {
218 rem = event_size - (len % event_size);
219 if (len % event_size == 0)
220 rem = 0;
221 }
222
223 kevent->name = kmalloc(len + rem, GFP_KERNEL);
224 if (unlikely(!kevent->name)) {
225 kmem_cache_free(event_cachep, kevent);
226 return NULL;
227 }
228 memcpy(kevent->name, name, len);
229 if (rem)
230 memset(kevent->name + len, 0, rem);
231 kevent->event.len = len + rem;
232 } else {
233 kevent->event.len = 0;
234 kevent->name = NULL;
235 }
236
237 return kevent;
238}
239
240/*
241 * inotify_dev_get_event - return the next event in the given dev's queue
242 *
243 * Caller must hold dev->ev_mutex.
244 */
245static inline struct inotify_kernel_event *
246inotify_dev_get_event(struct inotify_device *dev)
247{
248 return list_entry(dev->events.next, struct inotify_kernel_event, list);
249}
250
251/*
Yan Zheng1c17d182008-02-06 01:36:09 -0800252 * inotify_dev_get_last_event - return the last event in the given dev's queue
253 *
254 * Caller must hold dev->ev_mutex.
255 */
256static inline struct inotify_kernel_event *
257inotify_dev_get_last_event(struct inotify_device *dev)
258{
259 if (list_empty(&dev->events))
260 return NULL;
261 return list_entry(dev->events.prev, struct inotify_kernel_event, list);
262}
263
264/*
Amy Griffis2d9048e2006-06-01 13:10:59 -0700265 * inotify_dev_queue_event - event handler registered with core inotify, adds
266 * a new event to the given device
267 *
268 * Can sleep (calls kernel_event()).
269 */
270static void inotify_dev_queue_event(struct inotify_watch *w, u32 wd, u32 mask,
Amy Griffis7c297722006-06-01 13:11:01 -0700271 u32 cookie, const char *name,
272 struct inode *ignored)
Amy Griffis2d9048e2006-06-01 13:10:59 -0700273{
274 struct inotify_user_watch *watch;
275 struct inotify_device *dev;
276 struct inotify_kernel_event *kevent, *last;
277
278 watch = container_of(w, struct inotify_user_watch, wdata);
279 dev = watch->dev;
280
281 mutex_lock(&dev->ev_mutex);
282
283 /* we can safely put the watch as we don't reference it while
284 * generating the event
285 */
Ulisses Furquimac74c002008-02-08 04:18:16 -0800286 if (mask & IN_IGNORED || w->mask & IN_ONESHOT)
Amy Griffis2d9048e2006-06-01 13:10:59 -0700287 put_inotify_watch(w); /* final put */
288
289 /* coalescing: drop this event if it is a dupe of the previous */
Yan Zheng1c17d182008-02-06 01:36:09 -0800290 last = inotify_dev_get_last_event(dev);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700291 if (last && last->event.mask == mask && last->event.wd == wd &&
292 last->event.cookie == cookie) {
293 const char *lastname = last->name;
294
295 if (!name && !lastname)
296 goto out;
297 if (name && lastname && !strcmp(lastname, name))
298 goto out;
299 }
300
301 /* the queue overflowed and we already sent the Q_OVERFLOW event */
302 if (unlikely(dev->event_count > dev->max_events))
303 goto out;
304
305 /* if the queue overflows, we need to notify user space */
306 if (unlikely(dev->event_count == dev->max_events))
307 kevent = kernel_event(-1, IN_Q_OVERFLOW, cookie, NULL);
308 else
309 kevent = kernel_event(wd, mask, cookie, name);
310
311 if (unlikely(!kevent))
312 goto out;
313
314 /* queue the event and wake up anyone waiting */
315 dev->event_count++;
316 dev->queue_size += sizeof(struct inotify_event) + kevent->event.len;
317 list_add_tail(&kevent->list, &dev->events);
318 wake_up_interruptible(&dev->wq);
Dmitry Antipovbcfbf842008-02-06 01:36:19 -0800319 kill_fasync(&dev->fa, SIGIO, POLL_IN);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700320
321out:
322 mutex_unlock(&dev->ev_mutex);
323}
324
325/*
Nick Piggin16dbc6c2008-10-02 14:50:12 -0700326 * remove_kevent - cleans up the given kevent
Amy Griffis2d9048e2006-06-01 13:10:59 -0700327 *
328 * Caller must hold dev->ev_mutex.
329 */
330static void remove_kevent(struct inotify_device *dev,
331 struct inotify_kernel_event *kevent)
332{
333 list_del(&kevent->list);
334
335 dev->event_count--;
336 dev->queue_size -= sizeof(struct inotify_event) + kevent->event.len;
Nick Piggin16dbc6c2008-10-02 14:50:12 -0700337}
Amy Griffis2d9048e2006-06-01 13:10:59 -0700338
Nick Piggin16dbc6c2008-10-02 14:50:12 -0700339/*
340 * free_kevent - frees the given kevent.
341 */
342static void free_kevent(struct inotify_kernel_event *kevent)
343{
Amy Griffis2d9048e2006-06-01 13:10:59 -0700344 kfree(kevent->name);
345 kmem_cache_free(event_cachep, kevent);
346}
347
348/*
349 * inotify_dev_event_dequeue - destroy an event on the given device
350 *
351 * Caller must hold dev->ev_mutex.
352 */
353static void inotify_dev_event_dequeue(struct inotify_device *dev)
354{
355 if (!list_empty(&dev->events)) {
356 struct inotify_kernel_event *kevent;
357 kevent = inotify_dev_get_event(dev);
358 remove_kevent(dev, kevent);
Nick Piggin16dbc6c2008-10-02 14:50:12 -0700359 free_kevent(kevent);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700360 }
361}
362
363/*
Al Viro2d8f3032008-07-22 09:59:21 -0400364 * find_inode - resolve a user-given path to a specific inode
Amy Griffis2d9048e2006-06-01 13:10:59 -0700365 */
Al Viro2d8f3032008-07-22 09:59:21 -0400366static int find_inode(const char __user *dirname, struct path *path,
Amy Griffis2d9048e2006-06-01 13:10:59 -0700367 unsigned flags)
368{
369 int error;
370
Al Viro2d8f3032008-07-22 09:59:21 -0400371 error = user_path_at(AT_FDCWD, dirname, flags, path);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700372 if (error)
373 return error;
374 /* you can only watch an inode if you have read permissions on it */
Al Viro2d8f3032008-07-22 09:59:21 -0400375 error = inode_permission(path->dentry->d_inode, MAY_READ);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700376 if (error)
Al Viro2d8f3032008-07-22 09:59:21 -0400377 path_put(path);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700378 return error;
379}
380
381/*
382 * create_watch - creates a watch on the given device.
383 *
384 * Callers must hold dev->up_mutex.
385 */
386static int create_watch(struct inotify_device *dev, struct inode *inode,
387 u32 mask)
388{
389 struct inotify_user_watch *watch;
390 int ret;
391
392 if (atomic_read(&dev->user->inotify_watches) >=
393 inotify_max_user_watches)
394 return -ENOSPC;
395
396 watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL);
397 if (unlikely(!watch))
398 return -ENOMEM;
399
400 /* save a reference to device and bump the count to make it official */
401 get_inotify_dev(dev);
402 watch->dev = dev;
403
404 atomic_inc(&dev->user->inotify_watches);
405
Amy Griffisa9dc9712006-06-01 13:11:03 -0700406 inotify_init_watch(&watch->wdata);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700407 ret = inotify_add_watch(dev->ih, &watch->wdata, inode, mask);
408 if (ret < 0)
409 free_inotify_user_watch(&watch->wdata);
410
411 return ret;
412}
413
414/* Device Interface */
415
416static unsigned int inotify_poll(struct file *file, poll_table *wait)
417{
418 struct inotify_device *dev = file->private_data;
419 int ret = 0;
420
421 poll_wait(file, &dev->wq, wait);
422 mutex_lock(&dev->ev_mutex);
423 if (!list_empty(&dev->events))
424 ret = POLLIN | POLLRDNORM;
425 mutex_unlock(&dev->ev_mutex);
426
427 return ret;
428}
429
430static ssize_t inotify_read(struct file *file, char __user *buf,
431 size_t count, loff_t *pos)
432{
433 size_t event_size = sizeof (struct inotify_event);
434 struct inotify_device *dev;
435 char __user *start;
436 int ret;
437 DEFINE_WAIT(wait);
438
439 start = buf;
440 dev = file->private_data;
441
442 while (1) {
Amy Griffis2d9048e2006-06-01 13:10:59 -0700443
444 prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE);
445
446 mutex_lock(&dev->ev_mutex);
Nick Piggin16dbc6c2008-10-02 14:50:12 -0700447 if (!list_empty(&dev->events)) {
Amy Griffis2d9048e2006-06-01 13:10:59 -0700448 ret = 0;
449 break;
450 }
Nick Piggin16dbc6c2008-10-02 14:50:12 -0700451 mutex_unlock(&dev->ev_mutex);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700452
453 if (file->f_flags & O_NONBLOCK) {
454 ret = -EAGAIN;
455 break;
456 }
457
458 if (signal_pending(current)) {
459 ret = -EINTR;
460 break;
461 }
462
463 schedule();
464 }
465
466 finish_wait(&dev->wq, &wait);
467 if (ret)
468 return ret;
469
Amy Griffis2d9048e2006-06-01 13:10:59 -0700470 while (1) {
471 struct inotify_kernel_event *kevent;
472
473 ret = buf - start;
474 if (list_empty(&dev->events))
475 break;
476
477 kevent = inotify_dev_get_event(dev);
Nick Pigginf9e4acf2007-02-12 00:51:59 -0800478 if (event_size + kevent->event.len > count) {
479 if (ret == 0 && count > 0) {
480 /*
481 * could not get a single event because we
482 * didn't have enough buffer space.
483 */
484 ret = -EINVAL;
485 }
Amy Griffis2d9048e2006-06-01 13:10:59 -0700486 break;
Nick Pigginf9e4acf2007-02-12 00:51:59 -0800487 }
Nick Piggin16dbc6c2008-10-02 14:50:12 -0700488 remove_kevent(dev, kevent);
489
490 /*
491 * Must perform the copy_to_user outside the mutex in order
492 * to avoid a lock order reversal with mmap_sem.
493 */
494 mutex_unlock(&dev->ev_mutex);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700495
496 if (copy_to_user(buf, &kevent->event, event_size)) {
497 ret = -EFAULT;
498 break;
499 }
500 buf += event_size;
501 count -= event_size;
502
503 if (kevent->name) {
504 if (copy_to_user(buf, kevent->name, kevent->event.len)){
505 ret = -EFAULT;
506 break;
507 }
508 buf += kevent->event.len;
509 count -= kevent->event.len;
510 }
511
Nick Piggin16dbc6c2008-10-02 14:50:12 -0700512 free_kevent(kevent);
513
514 mutex_lock(&dev->ev_mutex);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700515 }
516 mutex_unlock(&dev->ev_mutex);
517
518 return ret;
519}
520
Dmitry Antipovbcfbf842008-02-06 01:36:19 -0800521static int inotify_fasync(int fd, struct file *file, int on)
522{
523 struct inotify_device *dev = file->private_data;
524
525 return fasync_helper(fd, file, on, &dev->fa) >= 0 ? 0 : -EIO;
526}
527
Amy Griffis2d9048e2006-06-01 13:10:59 -0700528static int inotify_release(struct inode *ignored, struct file *file)
529{
530 struct inotify_device *dev = file->private_data;
531
532 inotify_destroy(dev->ih);
533
534 /* destroy all of the events on this device */
535 mutex_lock(&dev->ev_mutex);
536 while (!list_empty(&dev->events))
537 inotify_dev_event_dequeue(dev);
538 mutex_unlock(&dev->ev_mutex);
539
Dmitry Antipovbcfbf842008-02-06 01:36:19 -0800540 if (file->f_flags & FASYNC)
541 inotify_fasync(-1, file, 0);
542
Amy Griffis2d9048e2006-06-01 13:10:59 -0700543 /* free this device: the put matching the get in inotify_init() */
544 put_inotify_dev(dev);
545
546 return 0;
547}
548
549static long inotify_ioctl(struct file *file, unsigned int cmd,
550 unsigned long arg)
551{
552 struct inotify_device *dev;
553 void __user *p;
554 int ret = -ENOTTY;
555
556 dev = file->private_data;
557 p = (void __user *) arg;
558
559 switch (cmd) {
560 case FIONREAD:
561 ret = put_user(dev->queue_size, (int __user *) p);
562 break;
563 }
564
565 return ret;
566}
567
568static const struct file_operations inotify_fops = {
569 .poll = inotify_poll,
570 .read = inotify_read,
Dmitry Antipovbcfbf842008-02-06 01:36:19 -0800571 .fasync = inotify_fasync,
Amy Griffis2d9048e2006-06-01 13:10:59 -0700572 .release = inotify_release,
573 .unlocked_ioctl = inotify_ioctl,
574 .compat_ioctl = inotify_ioctl,
575};
576
577static const struct inotify_operations inotify_user_ops = {
578 .handle_event = inotify_dev_queue_event,
579 .destroy_watch = free_inotify_user_watch,
580};
581
Ulrich Drepper40065532008-07-23 21:29:32 -0700582asmlinkage long sys_inotify_init1(int flags)
Amy Griffis2d9048e2006-06-01 13:10:59 -0700583{
584 struct inotify_device *dev;
585 struct inotify_handle *ih;
586 struct user_struct *user;
587 struct file *filp;
588 int fd, ret;
589
Ulrich Dreppere38b36f2008-07-23 21:29:42 -0700590 /* Check the IN_* constants for consistency. */
591 BUILD_BUG_ON(IN_CLOEXEC != O_CLOEXEC);
592 BUILD_BUG_ON(IN_NONBLOCK != O_NONBLOCK);
593
Ulrich Drepper510df2d2008-07-23 21:29:41 -0700594 if (flags & ~(IN_CLOEXEC | IN_NONBLOCK))
Ulrich Drepper40065532008-07-23 21:29:32 -0700595 return -EINVAL;
596
597 fd = get_unused_fd_flags(flags & O_CLOEXEC);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700598 if (fd < 0)
599 return fd;
600
601 filp = get_empty_filp();
602 if (!filp) {
603 ret = -ENFILE;
604 goto out_put_fd;
605 }
606
607 user = get_uid(current->user);
608 if (unlikely(atomic_read(&user->inotify_devs) >=
609 inotify_max_user_instances)) {
610 ret = -EMFILE;
611 goto out_free_uid;
612 }
613
614 dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL);
615 if (unlikely(!dev)) {
616 ret = -ENOMEM;
617 goto out_free_uid;
618 }
619
620 ih = inotify_init(&inotify_user_ops);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -0700621 if (IS_ERR(ih)) {
Amy Griffis2d9048e2006-06-01 13:10:59 -0700622 ret = PTR_ERR(ih);
623 goto out_free_dev;
624 }
625 dev->ih = ih;
Dmitry Antipovbcfbf842008-02-06 01:36:19 -0800626 dev->fa = NULL;
Amy Griffis2d9048e2006-06-01 13:10:59 -0700627
628 filp->f_op = &inotify_fops;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800629 filp->f_path.mnt = mntget(inotify_mnt);
630 filp->f_path.dentry = dget(inotify_mnt->mnt_root);
631 filp->f_mapping = filp->f_path.dentry->d_inode->i_mapping;
Amy Griffis2d9048e2006-06-01 13:10:59 -0700632 filp->f_mode = FMODE_READ;
Ulrich Drepper510df2d2008-07-23 21:29:41 -0700633 filp->f_flags = O_RDONLY | (flags & O_NONBLOCK);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700634 filp->private_data = dev;
635
636 INIT_LIST_HEAD(&dev->events);
637 init_waitqueue_head(&dev->wq);
638 mutex_init(&dev->ev_mutex);
639 mutex_init(&dev->up_mutex);
640 dev->event_count = 0;
641 dev->queue_size = 0;
642 dev->max_events = inotify_max_queued_events;
643 dev->user = user;
644 atomic_set(&dev->count, 0);
645
646 get_inotify_dev(dev);
647 atomic_inc(&user->inotify_devs);
648 fd_install(fd, filp);
649
650 return fd;
651out_free_dev:
652 kfree(dev);
653out_free_uid:
654 free_uid(user);
655 put_filp(filp);
656out_put_fd:
657 put_unused_fd(fd);
658 return ret;
659}
660
Ulrich Drepper40065532008-07-23 21:29:32 -0700661asmlinkage long sys_inotify_init(void)
662{
663 return sys_inotify_init1(0);
664}
665
Al Viro2d8f3032008-07-22 09:59:21 -0400666asmlinkage long sys_inotify_add_watch(int fd, const char __user *pathname, u32 mask)
Amy Griffis2d9048e2006-06-01 13:10:59 -0700667{
668 struct inode *inode;
669 struct inotify_device *dev;
Al Viro2d8f3032008-07-22 09:59:21 -0400670 struct path path;
Amy Griffis2d9048e2006-06-01 13:10:59 -0700671 struct file *filp;
672 int ret, fput_needed;
673 unsigned flags = 0;
674
675 filp = fget_light(fd, &fput_needed);
676 if (unlikely(!filp))
677 return -EBADF;
678
679 /* verify that this is indeed an inotify instance */
680 if (unlikely(filp->f_op != &inotify_fops)) {
681 ret = -EINVAL;
682 goto fput_and_out;
683 }
684
685 if (!(mask & IN_DONT_FOLLOW))
686 flags |= LOOKUP_FOLLOW;
687 if (mask & IN_ONLYDIR)
688 flags |= LOOKUP_DIRECTORY;
689
Al Viro2d8f3032008-07-22 09:59:21 -0400690 ret = find_inode(pathname, &path, flags);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700691 if (unlikely(ret))
692 goto fput_and_out;
693
Al Viro2d8f3032008-07-22 09:59:21 -0400694 /* inode held in place by reference to path; dev by fget on fd */
695 inode = path.dentry->d_inode;
Amy Griffis2d9048e2006-06-01 13:10:59 -0700696 dev = filp->private_data;
697
698 mutex_lock(&dev->up_mutex);
699 ret = inotify_find_update_watch(dev->ih, inode, mask);
700 if (ret == -ENOENT)
701 ret = create_watch(dev, inode, mask);
702 mutex_unlock(&dev->up_mutex);
703
Al Viro2d8f3032008-07-22 09:59:21 -0400704 path_put(&path);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700705fput_and_out:
706 fput_light(filp, fput_needed);
707 return ret;
708}
709
710asmlinkage long sys_inotify_rm_watch(int fd, u32 wd)
711{
712 struct file *filp;
713 struct inotify_device *dev;
714 int ret, fput_needed;
715
716 filp = fget_light(fd, &fput_needed);
717 if (unlikely(!filp))
718 return -EBADF;
719
720 /* verify that this is indeed an inotify instance */
721 if (unlikely(filp->f_op != &inotify_fops)) {
722 ret = -EINVAL;
723 goto out;
724 }
725
726 dev = filp->private_data;
727
728 /* we free our watch data when we get IN_IGNORED */
729 ret = inotify_rm_wd(dev->ih, wd);
730
731out:
732 fput_light(filp, fput_needed);
733 return ret;
734}
735
David Howells454e2392006-06-23 02:02:57 -0700736static int
Amy Griffis2d9048e2006-06-01 13:10:59 -0700737inotify_get_sb(struct file_system_type *fs_type, int flags,
David Howells454e2392006-06-23 02:02:57 -0700738 const char *dev_name, void *data, struct vfsmount *mnt)
Amy Griffis2d9048e2006-06-01 13:10:59 -0700739{
Andrey Mirkinfd5eea42007-10-16 23:30:13 -0700740 return get_sb_pseudo(fs_type, "inotify", NULL,
741 INOTIFYFS_SUPER_MAGIC, mnt);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700742}
743
744static struct file_system_type inotify_fs_type = {
745 .name = "inotifyfs",
746 .get_sb = inotify_get_sb,
747 .kill_sb = kill_anon_super,
748};
749
750/*
751 * inotify_user_setup - Our initialization function. Note that we cannnot return
752 * error because we have compiled-in VFS hooks. So an (unlikely) failure here
753 * must result in panic().
754 */
755static int __init inotify_user_setup(void)
756{
757 int ret;
758
759 ret = register_filesystem(&inotify_fs_type);
760 if (unlikely(ret))
761 panic("inotify: register_filesystem returned %d!\n", ret);
762
763 inotify_mnt = kern_mount(&inotify_fs_type);
764 if (IS_ERR(inotify_mnt))
765 panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt));
766
767 inotify_max_queued_events = 16384;
768 inotify_max_user_instances = 128;
769 inotify_max_user_watches = 8192;
770
771 watch_cachep = kmem_cache_create("inotify_watch_cache",
772 sizeof(struct inotify_user_watch),
Paul Mundt20c2df82007-07-20 10:11:58 +0900773 0, SLAB_PANIC, NULL);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700774 event_cachep = kmem_cache_create("inotify_event_cache",
775 sizeof(struct inotify_kernel_event),
Paul Mundt20c2df82007-07-20 10:11:58 +0900776 0, SLAB_PANIC, NULL);
Amy Griffis2d9048e2006-06-01 13:10:59 -0700777
778 return 0;
779}
780
781module_init(inotify_user_setup);