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 * Copyright (C) 2009 Eric Paris <Red Hat Inc> 12 * inotify was largely rewriten to make use of the fsnotify infrastructure 13 * 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 25#include <linux/file.h> 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 */ 30#include <linux/inotify.h> 31#include <linux/kernel.h> /* roundup() */ 32#include <linux/namei.h> /* LOOKUP_FOLLOW */ 33#include <linux/sched.h> /* struct user */ 34#include <linux/slab.h> /* struct kmem_cache */ 35#include <linux/syscalls.h> 36#include <linux/types.h> 37#include <linux/anon_inodes.h> 38#include <linux/uaccess.h> 39#include <linux/poll.h> 40#include <linux/wait.h> 41 42#include "inotify.h" 43#include "../fdinfo.h" 44 45#include <asm/ioctls.h> 46 47/* these are configurable via /proc/sys/fs/inotify/ */ 48static int inotify_max_user_instances __read_mostly; 49static int inotify_max_queued_events __read_mostly; 50static int inotify_max_user_watches __read_mostly; 51 52static struct kmem_cache *inotify_inode_mark_cachep __read_mostly; 53 54#ifdef CONFIG_SYSCTL 55 56#include <linux/sysctl.h> 57 58static int zero; 59 60struct ctl_table inotify_table[] = { 61 { 62 .procname = "max_user_instances", 63 .data = &inotify_max_user_instances, 64 .maxlen = sizeof(int), 65 .mode = 0644, 66 .proc_handler = proc_dointvec_minmax, 67 .extra1 = &zero, 68 }, 69 { 70 .procname = "max_user_watches", 71 .data = &inotify_max_user_watches, 72 .maxlen = sizeof(int), 73 .mode = 0644, 74 .proc_handler = proc_dointvec_minmax, 75 .extra1 = &zero, 76 }, 77 { 78 .procname = "max_queued_events", 79 .data = &inotify_max_queued_events, 80 .maxlen = sizeof(int), 81 .mode = 0644, 82 .proc_handler = proc_dointvec_minmax, 83 .extra1 = &zero 84 }, 85 { } 86}; 87#endif /* CONFIG_SYSCTL */ 88 89static inline __u32 inotify_arg_to_mask(u32 arg) 90{ 91 __u32 mask; 92 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); 98 99 /* mask off the flags used to open the fd */ 100 mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT | IN_EXCL_UNLINK)); 101 102 return mask; 103} 104 105static inline u32 inotify_mask_to_arg(__u32 mask) 106{ 107 return mask & (IN_ALL_EVENTS | IN_ISDIR | IN_UNMOUNT | IN_IGNORED | 108 IN_Q_OVERFLOW); 109} 110 111/* intofiy userspace file descriptor functions */ 112static unsigned int inotify_poll(struct file *file, poll_table *wait) 113{ 114 struct fsnotify_group *group = file->private_data; 115 int ret = 0; 116 117 poll_wait(file, &group->notification_waitq, wait); 118 mutex_lock(&group->notification_mutex); 119 if (!fsnotify_notify_queue_is_empty(group)) 120 ret = POLLIN | POLLRDNORM; 121 mutex_unlock(&group->notification_mutex); 122 123 return ret; 124} 125 126static int round_event_name_len(struct fsnotify_event *fsn_event) 127{ 128 struct inotify_event_info *event; 129 130 event = INOTIFY_E(fsn_event); 131 if (!event->name_len) 132 return 0; 133 return roundup(event->name_len + 1, sizeof(struct inotify_event)); 134} 135 136/* 137 * Get an inotify_kernel_event if one exists and is small 138 * enough to fit in "count". Return an error pointer if 139 * not large enough. 140 * 141 * Called with the group->notification_mutex held. 142 */ 143static struct fsnotify_event *get_one_event(struct fsnotify_group *group, 144 size_t count) 145{ 146 size_t event_size = sizeof(struct inotify_event); 147 struct fsnotify_event *event; 148 149 if (fsnotify_notify_queue_is_empty(group)) 150 return NULL; 151 152 event = fsnotify_peek_first_event(group); 153 154 pr_debug("%s: group=%p event=%p\n", __func__, group, event); 155 156 event_size += round_event_name_len(event); 157 if (event_size > count) 158 return ERR_PTR(-EINVAL); 159 160 /* held the notification_mutex the whole time, so this is the 161 * same event we peeked above */ 162 fsnotify_remove_first_event(group); 163 164 return event; 165} 166 167/* 168 * Copy an event to user space, returning how much we copied. 169 * 170 * We already checked that the event size is smaller than the 171 * buffer we had in "get_one_event()" above. 172 */ 173static ssize_t copy_event_to_user(struct fsnotify_group *group, 174 struct fsnotify_event *fsn_event, 175 char __user *buf) 176{ 177 struct inotify_event inotify_event; 178 struct inotify_event_info *event; 179 size_t event_size = sizeof(struct inotify_event); 180 size_t name_len; 181 size_t pad_name_len; 182 183 pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event); 184 185 event = INOTIFY_E(fsn_event); 186 name_len = event->name_len; 187 /* 188 * round up name length so it is a multiple of event_size 189 * plus an extra byte for the terminating '\0'. 190 */ 191 pad_name_len = round_event_name_len(fsn_event); 192 inotify_event.len = pad_name_len; 193 inotify_event.mask = inotify_mask_to_arg(fsn_event->mask); 194 inotify_event.wd = event->wd; 195 inotify_event.cookie = event->sync_cookie; 196 197 /* send the main event */ 198 if (copy_to_user(buf, &inotify_event, event_size)) 199 return -EFAULT; 200 201 buf += event_size; 202 203 /* 204 * fsnotify only stores the pathname, so here we have to send the pathname 205 * and then pad that pathname out to a multiple of sizeof(inotify_event) 206 * with zeros. 207 */ 208 if (pad_name_len) { 209 /* copy the path name */ 210 if (copy_to_user(buf, event->name, name_len)) 211 return -EFAULT; 212 buf += name_len; 213 214 /* fill userspace with 0's */ 215 if (clear_user(buf, pad_name_len - name_len)) 216 return -EFAULT; 217 event_size += pad_name_len; 218 } 219 220 return event_size; 221} 222 223static ssize_t inotify_read(struct file *file, char __user *buf, 224 size_t count, loff_t *pos) 225{ 226 struct fsnotify_group *group; 227 struct fsnotify_event *kevent; 228 char __user *start; 229 int ret; 230 DEFINE_WAIT_FUNC(wait, woken_wake_function); 231 232 start = buf; 233 group = file->private_data; 234 235 add_wait_queue(&group->notification_waitq, &wait); 236 while (1) { 237 mutex_lock(&group->notification_mutex); 238 kevent = get_one_event(group, count); 239 mutex_unlock(&group->notification_mutex); 240 241 pr_debug("%s: group=%p kevent=%p\n", __func__, group, kevent); 242 243 if (kevent) { 244 ret = PTR_ERR(kevent); 245 if (IS_ERR(kevent)) 246 break; 247 ret = copy_event_to_user(group, kevent, buf); 248 fsnotify_destroy_event(group, kevent); 249 if (ret < 0) 250 break; 251 buf += ret; 252 count -= ret; 253 continue; 254 } 255 256 ret = -EAGAIN; 257 if (file->f_flags & O_NONBLOCK) 258 break; 259 ret = -ERESTARTSYS; 260 if (signal_pending(current)) 261 break; 262 263 if (start != buf) 264 break; 265 266 wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 267 } 268 remove_wait_queue(&group->notification_waitq, &wait); 269 270 if (start != buf && ret != -EFAULT) 271 ret = buf - start; 272 return ret; 273} 274 275static int inotify_release(struct inode *ignored, struct file *file) 276{ 277 struct fsnotify_group *group = file->private_data; 278 279 pr_debug("%s: group=%p\n", __func__, group); 280 281 /* free this group, matching get was inotify_init->fsnotify_obtain_group */ 282 fsnotify_destroy_group(group); 283 284 return 0; 285} 286 287static long inotify_ioctl(struct file *file, unsigned int cmd, 288 unsigned long arg) 289{ 290 struct fsnotify_group *group; 291 struct fsnotify_event *fsn_event; 292 void __user *p; 293 int ret = -ENOTTY; 294 size_t send_len = 0; 295 296 group = file->private_data; 297 p = (void __user *) arg; 298 299 pr_debug("%s: group=%p cmd=%u\n", __func__, group, cmd); 300 301 switch (cmd) { 302 case FIONREAD: 303 mutex_lock(&group->notification_mutex); 304 list_for_each_entry(fsn_event, &group->notification_list, 305 list) { 306 send_len += sizeof(struct inotify_event); 307 send_len += round_event_name_len(fsn_event); 308 } 309 mutex_unlock(&group->notification_mutex); 310 ret = put_user(send_len, (int __user *) p); 311 break; 312 } 313 314 return ret; 315} 316 317static const struct file_operations inotify_fops = { 318 .show_fdinfo = inotify_show_fdinfo, 319 .poll = inotify_poll, 320 .read = inotify_read, 321 .fasync = fsnotify_fasync, 322 .release = inotify_release, 323 .unlocked_ioctl = inotify_ioctl, 324 .compat_ioctl = inotify_ioctl, 325 .llseek = noop_llseek, 326}; 327 328 329/* 330 * find_inode - resolve a user-given path to a specific inode 331 */ 332static int inotify_find_inode(const char __user *dirname, struct path *path, unsigned flags) 333{ 334 int error; 335 336 error = user_path_at(AT_FDCWD, dirname, flags, path); 337 if (error) 338 return error; 339 /* you can only watch an inode if you have read permissions on it */ 340 error = inode_permission(path->dentry->d_inode, MAY_READ); 341 if (error) 342 path_put(path); 343 return error; 344} 345 346static int inotify_add_to_idr(struct idr *idr, spinlock_t *idr_lock, 347 struct inotify_inode_mark *i_mark) 348{ 349 int ret; 350 351 idr_preload(GFP_KERNEL); 352 spin_lock(idr_lock); 353 354 ret = idr_alloc_cyclic(idr, i_mark, 1, 0, GFP_NOWAIT); 355 if (ret >= 0) { 356 /* we added the mark to the idr, take a reference */ 357 i_mark->wd = ret; 358 fsnotify_get_mark(&i_mark->fsn_mark); 359 } 360 361 spin_unlock(idr_lock); 362 idr_preload_end(); 363 return ret < 0 ? ret : 0; 364} 365 366static struct inotify_inode_mark *inotify_idr_find_locked(struct fsnotify_group *group, 367 int wd) 368{ 369 struct idr *idr = &group->inotify_data.idr; 370 spinlock_t *idr_lock = &group->inotify_data.idr_lock; 371 struct inotify_inode_mark *i_mark; 372 373 assert_spin_locked(idr_lock); 374 375 i_mark = idr_find(idr, wd); 376 if (i_mark) { 377 struct fsnotify_mark *fsn_mark = &i_mark->fsn_mark; 378 379 fsnotify_get_mark(fsn_mark); 380 /* One ref for being in the idr, one ref we just took */ 381 BUG_ON(atomic_read(&fsn_mark->refcnt) < 2); 382 } 383 384 return i_mark; 385} 386 387static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group, 388 int wd) 389{ 390 struct inotify_inode_mark *i_mark; 391 spinlock_t *idr_lock = &group->inotify_data.idr_lock; 392 393 spin_lock(idr_lock); 394 i_mark = inotify_idr_find_locked(group, wd); 395 spin_unlock(idr_lock); 396 397 return i_mark; 398} 399 400static void do_inotify_remove_from_idr(struct fsnotify_group *group, 401 struct inotify_inode_mark *i_mark) 402{ 403 struct idr *idr = &group->inotify_data.idr; 404 spinlock_t *idr_lock = &group->inotify_data.idr_lock; 405 int wd = i_mark->wd; 406 407 assert_spin_locked(idr_lock); 408 409 idr_remove(idr, wd); 410 411 /* removed from the idr, drop that ref */ 412 fsnotify_put_mark(&i_mark->fsn_mark); 413} 414 415/* 416 * Remove the mark from the idr (if present) and drop the reference 417 * on the mark because it was in the idr. 418 */ 419static void inotify_remove_from_idr(struct fsnotify_group *group, 420 struct inotify_inode_mark *i_mark) 421{ 422 spinlock_t *idr_lock = &group->inotify_data.idr_lock; 423 struct inotify_inode_mark *found_i_mark = NULL; 424 int wd; 425 426 spin_lock(idr_lock); 427 wd = i_mark->wd; 428 429 /* 430 * does this i_mark think it is in the idr? we shouldn't get called 431 * if it wasn't.... 432 */ 433 if (wd == -1) { 434 WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" 435 " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, 436 i_mark->fsn_mark.group, i_mark->fsn_mark.inode); 437 goto out; 438 } 439 440 /* Lets look in the idr to see if we find it */ 441 found_i_mark = inotify_idr_find_locked(group, wd); 442 if (unlikely(!found_i_mark)) { 443 WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" 444 " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, 445 i_mark->fsn_mark.group, i_mark->fsn_mark.inode); 446 goto out; 447 } 448 449 /* 450 * We found an mark in the idr at the right wd, but it's 451 * not the mark we were told to remove. eparis seriously 452 * fucked up somewhere. 453 */ 454 if (unlikely(found_i_mark != i_mark)) { 455 WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p " 456 "mark->inode=%p found_i_mark=%p found_i_mark->wd=%d " 457 "found_i_mark->group=%p found_i_mark->inode=%p\n", 458 __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group, 459 i_mark->fsn_mark.inode, found_i_mark, found_i_mark->wd, 460 found_i_mark->fsn_mark.group, 461 found_i_mark->fsn_mark.inode); 462 goto out; 463 } 464 465 /* 466 * One ref for being in the idr 467 * one ref held by the caller trying to kill us 468 * one ref grabbed by inotify_idr_find 469 */ 470 if (unlikely(atomic_read(&i_mark->fsn_mark.refcnt) < 3)) { 471 printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" 472 " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, 473 i_mark->fsn_mark.group, i_mark->fsn_mark.inode); 474 /* we can't really recover with bad ref cnting.. */ 475 BUG(); 476 } 477 478 do_inotify_remove_from_idr(group, i_mark); 479out: 480 /* match the ref taken by inotify_idr_find_locked() */ 481 if (found_i_mark) 482 fsnotify_put_mark(&found_i_mark->fsn_mark); 483 i_mark->wd = -1; 484 spin_unlock(idr_lock); 485} 486 487/* 488 * Send IN_IGNORED for this wd, remove this wd from the idr. 489 */ 490void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, 491 struct fsnotify_group *group) 492{ 493 struct inotify_inode_mark *i_mark; 494 495 /* Queue ignore event for the watch */ 496 inotify_handle_event(group, NULL, fsn_mark, NULL, FS_IN_IGNORED, 497 NULL, FSNOTIFY_EVENT_NONE, NULL, 0); 498 499 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); 500 /* remove this mark from the idr */ 501 inotify_remove_from_idr(group, i_mark); 502 503 atomic_dec(&group->inotify_data.user->inotify_watches); 504} 505 506/* ding dong the mark is dead */ 507static void inotify_free_mark(struct fsnotify_mark *fsn_mark) 508{ 509 struct inotify_inode_mark *i_mark; 510 511 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); 512 513 kmem_cache_free(inotify_inode_mark_cachep, i_mark); 514} 515 516static int inotify_update_existing_watch(struct fsnotify_group *group, 517 struct inode *inode, 518 u32 arg) 519{ 520 struct fsnotify_mark *fsn_mark; 521 struct inotify_inode_mark *i_mark; 522 __u32 old_mask, new_mask; 523 __u32 mask; 524 int add = (arg & IN_MASK_ADD); 525 int ret; 526 527 mask = inotify_arg_to_mask(arg); 528 529 fsn_mark = fsnotify_find_inode_mark(group, inode); 530 if (!fsn_mark) 531 return -ENOENT; 532 533 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); 534 535 spin_lock(&fsn_mark->lock); 536 537 old_mask = fsn_mark->mask; 538 if (add) 539 fsnotify_set_mark_mask_locked(fsn_mark, (fsn_mark->mask | mask)); 540 else 541 fsnotify_set_mark_mask_locked(fsn_mark, mask); 542 new_mask = fsn_mark->mask; 543 544 spin_unlock(&fsn_mark->lock); 545 546 if (old_mask != new_mask) { 547 /* more bits in old than in new? */ 548 int dropped = (old_mask & ~new_mask); 549 /* more bits in this fsn_mark than the inode's mask? */ 550 int do_inode = (new_mask & ~inode->i_fsnotify_mask); 551 552 /* update the inode with this new fsn_mark */ 553 if (dropped || do_inode) 554 fsnotify_recalc_inode_mask(inode); 555 556 } 557 558 /* return the wd */ 559 ret = i_mark->wd; 560 561 /* match the get from fsnotify_find_mark() */ 562 fsnotify_put_mark(fsn_mark); 563 564 return ret; 565} 566 567static int inotify_new_watch(struct fsnotify_group *group, 568 struct inode *inode, 569 u32 arg) 570{ 571 struct inotify_inode_mark *tmp_i_mark; 572 __u32 mask; 573 int ret; 574 struct idr *idr = &group->inotify_data.idr; 575 spinlock_t *idr_lock = &group->inotify_data.idr_lock; 576 577 mask = inotify_arg_to_mask(arg); 578 579 tmp_i_mark = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); 580 if (unlikely(!tmp_i_mark)) 581 return -ENOMEM; 582 583 fsnotify_init_mark(&tmp_i_mark->fsn_mark, inotify_free_mark); 584 tmp_i_mark->fsn_mark.mask = mask; 585 tmp_i_mark->wd = -1; 586 587 ret = -ENOSPC; 588 if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) 589 goto out_err; 590 591 ret = inotify_add_to_idr(idr, idr_lock, tmp_i_mark); 592 if (ret) 593 goto out_err; 594 595 /* we are on the idr, now get on the inode */ 596 ret = fsnotify_add_mark_locked(&tmp_i_mark->fsn_mark, group, inode, 597 NULL, 0); 598 if (ret) { 599 /* we failed to get on the inode, get off the idr */ 600 inotify_remove_from_idr(group, tmp_i_mark); 601 goto out_err; 602 } 603 604 /* increment the number of watches the user has */ 605 atomic_inc(&group->inotify_data.user->inotify_watches); 606 607 /* return the watch descriptor for this new mark */ 608 ret = tmp_i_mark->wd; 609 610out_err: 611 /* match the ref from fsnotify_init_mark() */ 612 fsnotify_put_mark(&tmp_i_mark->fsn_mark); 613 614 return ret; 615} 616 617static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) 618{ 619 int ret = 0; 620 621 mutex_lock(&group->mark_mutex); 622 /* try to update and existing watch with the new arg */ 623 ret = inotify_update_existing_watch(group, inode, arg); 624 /* no mark present, try to add a new one */ 625 if (ret == -ENOENT) 626 ret = inotify_new_watch(group, inode, arg); 627 mutex_unlock(&group->mark_mutex); 628 629 return ret; 630} 631 632static struct fsnotify_group *inotify_new_group(unsigned int max_events) 633{ 634 struct fsnotify_group *group; 635 struct inotify_event_info *oevent; 636 637 group = fsnotify_alloc_group(&inotify_fsnotify_ops); 638 if (IS_ERR(group)) 639 return group; 640 641 oevent = kmalloc(sizeof(struct inotify_event_info), GFP_KERNEL); 642 if (unlikely(!oevent)) { 643 fsnotify_destroy_group(group); 644 return ERR_PTR(-ENOMEM); 645 } 646 group->overflow_event = &oevent->fse; 647 fsnotify_init_event(group->overflow_event, NULL, FS_Q_OVERFLOW); 648 oevent->wd = -1; 649 oevent->sync_cookie = 0; 650 oevent->name_len = 0; 651 652 group->max_events = max_events; 653 654 spin_lock_init(&group->inotify_data.idr_lock); 655 idr_init(&group->inotify_data.idr); 656 group->inotify_data.user = get_current_user(); 657 658 if (atomic_inc_return(&group->inotify_data.user->inotify_devs) > 659 inotify_max_user_instances) { 660 fsnotify_destroy_group(group); 661 return ERR_PTR(-EMFILE); 662 } 663 664 return group; 665} 666 667 668/* inotify syscalls */ 669SYSCALL_DEFINE1(inotify_init1, int, flags) 670{ 671 struct fsnotify_group *group; 672 int ret; 673 674 /* Check the IN_* constants for consistency. */ 675 BUILD_BUG_ON(IN_CLOEXEC != O_CLOEXEC); 676 BUILD_BUG_ON(IN_NONBLOCK != O_NONBLOCK); 677 678 if (flags & ~(IN_CLOEXEC | IN_NONBLOCK)) 679 return -EINVAL; 680 681 /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ 682 group = inotify_new_group(inotify_max_queued_events); 683 if (IS_ERR(group)) 684 return PTR_ERR(group); 685 686 ret = anon_inode_getfd("inotify", &inotify_fops, group, 687 O_RDONLY | flags); 688 if (ret < 0) 689 fsnotify_destroy_group(group); 690 691 return ret; 692} 693 694SYSCALL_DEFINE0(inotify_init) 695{ 696 return sys_inotify_init1(0); 697} 698 699SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname, 700 u32, mask) 701{ 702 struct fsnotify_group *group; 703 struct inode *inode; 704 struct path path; 705 struct fd f; 706 int ret; 707 unsigned flags = 0; 708 709 /* don't allow invalid bits: we don't want flags set */ 710 if (unlikely(!(mask & ALL_INOTIFY_BITS))) 711 return -EINVAL; 712 713 f = fdget(fd); 714 if (unlikely(!f.file)) 715 return -EBADF; 716 717 /* verify that this is indeed an inotify instance */ 718 if (unlikely(f.file->f_op != &inotify_fops)) { 719 ret = -EINVAL; 720 goto fput_and_out; 721 } 722 723 if (!(mask & IN_DONT_FOLLOW)) 724 flags |= LOOKUP_FOLLOW; 725 if (mask & IN_ONLYDIR) 726 flags |= LOOKUP_DIRECTORY; 727 728 ret = inotify_find_inode(pathname, &path, flags); 729 if (ret) 730 goto fput_and_out; 731 732 /* inode held in place by reference to path; group by fget on fd */ 733 inode = path.dentry->d_inode; 734 group = f.file->private_data; 735 736 /* create/update an inode mark */ 737 ret = inotify_update_watch(group, inode, mask); 738 path_put(&path); 739fput_and_out: 740 fdput(f); 741 return ret; 742} 743 744SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) 745{ 746 struct fsnotify_group *group; 747 struct inotify_inode_mark *i_mark; 748 struct fd f; 749 int ret = 0; 750 751 f = fdget(fd); 752 if (unlikely(!f.file)) 753 return -EBADF; 754 755 /* verify that this is indeed an inotify instance */ 756 ret = -EINVAL; 757 if (unlikely(f.file->f_op != &inotify_fops)) 758 goto out; 759 760 group = f.file->private_data; 761 762 ret = -EINVAL; 763 i_mark = inotify_idr_find(group, wd); 764 if (unlikely(!i_mark)) 765 goto out; 766 767 ret = 0; 768 769 fsnotify_destroy_mark(&i_mark->fsn_mark, group); 770 771 /* match ref taken by inotify_idr_find */ 772 fsnotify_put_mark(&i_mark->fsn_mark); 773 774out: 775 fdput(f); 776 return ret; 777} 778 779/* 780 * inotify_user_setup - Our initialization function. Note that we cannot return 781 * error because we have compiled-in VFS hooks. So an (unlikely) failure here 782 * must result in panic(). 783 */ 784static int __init inotify_user_setup(void) 785{ 786 BUILD_BUG_ON(IN_ACCESS != FS_ACCESS); 787 BUILD_BUG_ON(IN_MODIFY != FS_MODIFY); 788 BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB); 789 BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE); 790 BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); 791 BUILD_BUG_ON(IN_OPEN != FS_OPEN); 792 BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM); 793 BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO); 794 BUILD_BUG_ON(IN_CREATE != FS_CREATE); 795 BUILD_BUG_ON(IN_DELETE != FS_DELETE); 796 BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF); 797 BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF); 798 BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT); 799 BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW); 800 BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED); 801 BUILD_BUG_ON(IN_EXCL_UNLINK != FS_EXCL_UNLINK); 802 BUILD_BUG_ON(IN_ISDIR != FS_ISDIR); 803 BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT); 804 805 BUG_ON(hweight32(ALL_INOTIFY_BITS) != 21); 806 807 inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC); 808 809 inotify_max_queued_events = 16384; 810 inotify_max_user_instances = 128; 811 inotify_max_user_watches = 8192; 812 813 return 0; 814} 815module_init(inotify_user_setup); 816