1272eb014SEric Paris /* 2272eb014SEric Paris * fs/inotify_user.c - inotify support for userspace 3272eb014SEric Paris * 4272eb014SEric Paris * Authors: 5272eb014SEric Paris * John McCutchan <ttb@tentacle.dhs.org> 6272eb014SEric Paris * Robert Love <rml@novell.com> 7272eb014SEric Paris * 8272eb014SEric Paris * Copyright (C) 2005 John McCutchan 9272eb014SEric Paris * Copyright 2006 Hewlett-Packard Development Company, L.P. 10272eb014SEric Paris * 1163c882a0SEric Paris * Copyright (C) 2009 Eric Paris <Red Hat Inc> 1263c882a0SEric Paris * inotify was largely rewriten to make use of the fsnotify infrastructure 1363c882a0SEric Paris * 14272eb014SEric Paris * This program is free software; you can redistribute it and/or modify it 15272eb014SEric Paris * under the terms of the GNU General Public License as published by the 16272eb014SEric Paris * Free Software Foundation; either version 2, or (at your option) any 17272eb014SEric Paris * later version. 18272eb014SEric Paris * 19272eb014SEric Paris * This program is distributed in the hope that it will be useful, but 20272eb014SEric Paris * WITHOUT ANY WARRANTY; without even the implied warranty of 21272eb014SEric Paris * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 22272eb014SEric Paris * General Public License for more details. 23272eb014SEric Paris */ 24272eb014SEric Paris 25272eb014SEric Paris #include <linux/file.h> 2663c882a0SEric Paris #include <linux/fs.h> /* struct inode */ 2763c882a0SEric Paris #include <linux/fsnotify_backend.h> 2863c882a0SEric Paris #include <linux/idr.h> 2963c882a0SEric Paris #include <linux/init.h> /* module_init */ 30272eb014SEric Paris #include <linux/inotify.h> 3163c882a0SEric Paris #include <linux/kernel.h> /* roundup() */ 3263c882a0SEric Paris #include <linux/namei.h> /* LOOKUP_FOLLOW */ 3363c882a0SEric Paris #include <linux/sched.h> /* struct user */ 3463c882a0SEric Paris #include <linux/slab.h> /* struct kmem_cache */ 35272eb014SEric Paris #include <linux/syscalls.h> 3663c882a0SEric Paris #include <linux/types.h> 37c44dcc56SAl Viro #include <linux/anon_inodes.h> 3863c882a0SEric Paris #include <linux/uaccess.h> 3963c882a0SEric Paris #include <linux/poll.h> 4063c882a0SEric Paris #include <linux/wait.h> 4163c882a0SEric Paris 4263c882a0SEric Paris #include "inotify.h" 43272eb014SEric Paris 44272eb014SEric Paris #include <asm/ioctls.h> 45272eb014SEric Paris 46272eb014SEric Paris /* these are configurable via /proc/sys/fs/inotify/ */ 47272eb014SEric Paris static int inotify_max_user_instances __read_mostly; 48272eb014SEric Paris static int inotify_max_queued_events __read_mostly; 4963c882a0SEric Paris int inotify_max_user_watches __read_mostly; 5063c882a0SEric Paris 5163c882a0SEric Paris static struct kmem_cache *inotify_inode_mark_cachep __read_mostly; 5263c882a0SEric Paris struct kmem_cache *event_priv_cachep __read_mostly; 53272eb014SEric Paris 54272eb014SEric Paris /* 5563c882a0SEric Paris * When inotify registers a new group it increments this and uses that 5663c882a0SEric Paris * value as an offset to set the fsnotify group "name" and priority. 57272eb014SEric Paris */ 5863c882a0SEric Paris static atomic_t inotify_grp_num; 59272eb014SEric Paris 60272eb014SEric Paris #ifdef CONFIG_SYSCTL 61272eb014SEric Paris 62272eb014SEric Paris #include <linux/sysctl.h> 63272eb014SEric Paris 64272eb014SEric Paris static int zero; 65272eb014SEric Paris 66272eb014SEric Paris ctl_table inotify_table[] = { 67272eb014SEric Paris { 68272eb014SEric Paris .procname = "max_user_instances", 69272eb014SEric Paris .data = &inotify_max_user_instances, 70272eb014SEric Paris .maxlen = sizeof(int), 71272eb014SEric Paris .mode = 0644, 726d456111SEric W. Biederman .proc_handler = proc_dointvec_minmax, 73272eb014SEric Paris .extra1 = &zero, 74272eb014SEric Paris }, 75272eb014SEric Paris { 76272eb014SEric Paris .procname = "max_user_watches", 77272eb014SEric Paris .data = &inotify_max_user_watches, 78272eb014SEric Paris .maxlen = sizeof(int), 79272eb014SEric Paris .mode = 0644, 806d456111SEric W. Biederman .proc_handler = proc_dointvec_minmax, 81272eb014SEric Paris .extra1 = &zero, 82272eb014SEric Paris }, 83272eb014SEric Paris { 84272eb014SEric Paris .procname = "max_queued_events", 85272eb014SEric Paris .data = &inotify_max_queued_events, 86272eb014SEric Paris .maxlen = sizeof(int), 87272eb014SEric Paris .mode = 0644, 886d456111SEric W. Biederman .proc_handler = proc_dointvec_minmax, 89272eb014SEric Paris .extra1 = &zero 90272eb014SEric Paris }, 91ab09203eSEric W. Biederman { } 92272eb014SEric Paris }; 93272eb014SEric Paris #endif /* CONFIG_SYSCTL */ 94272eb014SEric Paris 9563c882a0SEric Paris static inline __u32 inotify_arg_to_mask(u32 arg) 96272eb014SEric Paris { 9763c882a0SEric Paris __u32 mask; 9863c882a0SEric Paris 9963c882a0SEric Paris /* everything should accept their own ignored and cares about children */ 10063c882a0SEric Paris mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD); 10163c882a0SEric Paris 10263c882a0SEric Paris /* mask off the flags used to open the fd */ 10363c882a0SEric Paris mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT)); 10463c882a0SEric Paris 10563c882a0SEric Paris return mask; 106272eb014SEric Paris } 107272eb014SEric Paris 10863c882a0SEric Paris static inline u32 inotify_mask_to_arg(__u32 mask) 109272eb014SEric Paris { 11063c882a0SEric Paris return mask & (IN_ALL_EVENTS | IN_ISDIR | IN_UNMOUNT | IN_IGNORED | 11163c882a0SEric Paris IN_Q_OVERFLOW); 112272eb014SEric Paris } 113272eb014SEric Paris 11463c882a0SEric Paris /* intofiy userspace file descriptor functions */ 115272eb014SEric Paris static unsigned int inotify_poll(struct file *file, poll_table *wait) 116272eb014SEric Paris { 11763c882a0SEric Paris struct fsnotify_group *group = file->private_data; 118272eb014SEric Paris int ret = 0; 119272eb014SEric Paris 12063c882a0SEric Paris poll_wait(file, &group->notification_waitq, wait); 12163c882a0SEric Paris mutex_lock(&group->notification_mutex); 12263c882a0SEric Paris if (!fsnotify_notify_queue_is_empty(group)) 123272eb014SEric Paris ret = POLLIN | POLLRDNORM; 12463c882a0SEric Paris mutex_unlock(&group->notification_mutex); 125272eb014SEric Paris 126272eb014SEric Paris return ret; 127272eb014SEric Paris } 128272eb014SEric Paris 1293632dee2SVegard Nossum /* 1303632dee2SVegard Nossum * Get an inotify_kernel_event if one exists and is small 1313632dee2SVegard Nossum * enough to fit in "count". Return an error pointer if 1323632dee2SVegard Nossum * not large enough. 1333632dee2SVegard Nossum * 13463c882a0SEric Paris * Called with the group->notification_mutex held. 1353632dee2SVegard Nossum */ 13663c882a0SEric Paris static struct fsnotify_event *get_one_event(struct fsnotify_group *group, 1373632dee2SVegard Nossum size_t count) 1383632dee2SVegard Nossum { 1393632dee2SVegard Nossum size_t event_size = sizeof(struct inotify_event); 14063c882a0SEric Paris struct fsnotify_event *event; 1413632dee2SVegard Nossum 14263c882a0SEric Paris if (fsnotify_notify_queue_is_empty(group)) 1433632dee2SVegard Nossum return NULL; 1443632dee2SVegard Nossum 14563c882a0SEric Paris event = fsnotify_peek_notify_event(group); 14663c882a0SEric Paris 14783cb10f0SEric Paris if (event->name_len) 14883cb10f0SEric Paris event_size += roundup(event->name_len + 1, event_size); 1493632dee2SVegard Nossum 1503632dee2SVegard Nossum if (event_size > count) 1513632dee2SVegard Nossum return ERR_PTR(-EINVAL); 1523632dee2SVegard Nossum 15363c882a0SEric Paris /* held the notification_mutex the whole time, so this is the 15463c882a0SEric Paris * same event we peeked above */ 15563c882a0SEric Paris fsnotify_remove_notify_event(group); 15663c882a0SEric Paris 15763c882a0SEric Paris return event; 1583632dee2SVegard Nossum } 1593632dee2SVegard Nossum 1603632dee2SVegard Nossum /* 1613632dee2SVegard Nossum * Copy an event to user space, returning how much we copied. 1623632dee2SVegard Nossum * 1633632dee2SVegard Nossum * We already checked that the event size is smaller than the 1643632dee2SVegard Nossum * buffer we had in "get_one_event()" above. 1653632dee2SVegard Nossum */ 16663c882a0SEric Paris static ssize_t copy_event_to_user(struct fsnotify_group *group, 16763c882a0SEric Paris struct fsnotify_event *event, 1683632dee2SVegard Nossum char __user *buf) 1693632dee2SVegard Nossum { 17063c882a0SEric Paris struct inotify_event inotify_event; 17163c882a0SEric Paris struct fsnotify_event_private_data *fsn_priv; 17263c882a0SEric Paris struct inotify_event_private_data *priv; 1733632dee2SVegard Nossum size_t event_size = sizeof(struct inotify_event); 174b962e731SBrian Rogers size_t name_len = 0; 1753632dee2SVegard Nossum 17663c882a0SEric Paris /* we get the inotify watch descriptor from the event private data */ 17763c882a0SEric Paris spin_lock(&event->lock); 17863c882a0SEric Paris fsn_priv = fsnotify_remove_priv_from_event(group, event); 17963c882a0SEric Paris spin_unlock(&event->lock); 18063c882a0SEric Paris 18163c882a0SEric Paris if (!fsn_priv) 18263c882a0SEric Paris inotify_event.wd = -1; 18363c882a0SEric Paris else { 18463c882a0SEric Paris priv = container_of(fsn_priv, struct inotify_event_private_data, 18563c882a0SEric Paris fsnotify_event_priv_data); 18663c882a0SEric Paris inotify_event.wd = priv->wd; 18763c882a0SEric Paris inotify_free_event_priv(fsn_priv); 18863c882a0SEric Paris } 18963c882a0SEric Paris 190b962e731SBrian Rogers /* 191b962e731SBrian Rogers * round up event->name_len so it is a multiple of event_size 1920db501bdSEric W. Biederman * plus an extra byte for the terminating '\0'. 1930db501bdSEric W. Biederman */ 194b962e731SBrian Rogers if (event->name_len) 1950db501bdSEric W. Biederman name_len = roundup(event->name_len + 1, event_size); 19663c882a0SEric Paris inotify_event.len = name_len; 19763c882a0SEric Paris 19863c882a0SEric Paris inotify_event.mask = inotify_mask_to_arg(event->mask); 19963c882a0SEric Paris inotify_event.cookie = event->sync_cookie; 20063c882a0SEric Paris 20163c882a0SEric Paris /* send the main event */ 20263c882a0SEric Paris if (copy_to_user(buf, &inotify_event, event_size)) 2033632dee2SVegard Nossum return -EFAULT; 2043632dee2SVegard Nossum 2053632dee2SVegard Nossum buf += event_size; 2063632dee2SVegard Nossum 20763c882a0SEric Paris /* 20863c882a0SEric Paris * fsnotify only stores the pathname, so here we have to send the pathname 20963c882a0SEric Paris * and then pad that pathname out to a multiple of sizeof(inotify_event) 21063c882a0SEric Paris * with zeros. I get my zeros from the nul_inotify_event. 21163c882a0SEric Paris */ 21263c882a0SEric Paris if (name_len) { 21363c882a0SEric Paris unsigned int len_to_zero = name_len - event->name_len; 21463c882a0SEric Paris /* copy the path name */ 21563c882a0SEric Paris if (copy_to_user(buf, event->file_name, event->name_len)) 2163632dee2SVegard Nossum return -EFAULT; 21763c882a0SEric Paris buf += event->name_len; 2183632dee2SVegard Nossum 2190db501bdSEric W. Biederman /* fill userspace with 0's */ 2200db501bdSEric W. Biederman if (clear_user(buf, len_to_zero)) 22163c882a0SEric Paris return -EFAULT; 22263c882a0SEric Paris buf += len_to_zero; 22363c882a0SEric Paris event_size += name_len; 2243632dee2SVegard Nossum } 22563c882a0SEric Paris 2263632dee2SVegard Nossum return event_size; 2273632dee2SVegard Nossum } 2283632dee2SVegard Nossum 229272eb014SEric Paris static ssize_t inotify_read(struct file *file, char __user *buf, 230272eb014SEric Paris size_t count, loff_t *pos) 231272eb014SEric Paris { 23263c882a0SEric Paris struct fsnotify_group *group; 23363c882a0SEric Paris struct fsnotify_event *kevent; 234272eb014SEric Paris char __user *start; 235272eb014SEric Paris int ret; 236272eb014SEric Paris DEFINE_WAIT(wait); 237272eb014SEric Paris 238272eb014SEric Paris start = buf; 23963c882a0SEric Paris group = file->private_data; 240272eb014SEric Paris 241272eb014SEric Paris while (1) { 24263c882a0SEric Paris prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); 243272eb014SEric Paris 24463c882a0SEric Paris mutex_lock(&group->notification_mutex); 24563c882a0SEric Paris kevent = get_one_event(group, count); 24663c882a0SEric Paris mutex_unlock(&group->notification_mutex); 247272eb014SEric Paris 2483632dee2SVegard Nossum if (kevent) { 2493632dee2SVegard Nossum ret = PTR_ERR(kevent); 2503632dee2SVegard Nossum if (IS_ERR(kevent)) 251272eb014SEric Paris break; 25263c882a0SEric Paris ret = copy_event_to_user(group, kevent, buf); 25363c882a0SEric Paris fsnotify_put_event(kevent); 2543632dee2SVegard Nossum if (ret < 0) 2553632dee2SVegard Nossum break; 2563632dee2SVegard Nossum buf += ret; 2573632dee2SVegard Nossum count -= ret; 2583632dee2SVegard Nossum continue; 259272eb014SEric Paris } 260272eb014SEric Paris 2613632dee2SVegard Nossum ret = -EAGAIN; 2623632dee2SVegard Nossum if (file->f_flags & O_NONBLOCK) 263272eb014SEric Paris break; 2643632dee2SVegard Nossum ret = -EINTR; 2653632dee2SVegard Nossum if (signal_pending(current)) 2663632dee2SVegard Nossum break; 2673632dee2SVegard Nossum 2683632dee2SVegard Nossum if (start != buf) 2693632dee2SVegard Nossum break; 270272eb014SEric Paris 271272eb014SEric Paris schedule(); 272272eb014SEric Paris } 273272eb014SEric Paris 27463c882a0SEric Paris finish_wait(&group->notification_waitq, &wait); 2753632dee2SVegard Nossum if (start != buf && ret != -EFAULT) 276272eb014SEric Paris ret = buf - start; 277272eb014SEric Paris return ret; 278272eb014SEric Paris } 279272eb014SEric Paris 280272eb014SEric Paris static int inotify_fasync(int fd, struct file *file, int on) 281272eb014SEric Paris { 28263c882a0SEric Paris struct fsnotify_group *group = file->private_data; 283272eb014SEric Paris 28463c882a0SEric Paris return fasync_helper(fd, file, on, &group->inotify_data.fa) >= 0 ? 0 : -EIO; 285272eb014SEric Paris } 286272eb014SEric Paris 287272eb014SEric Paris static int inotify_release(struct inode *ignored, struct file *file) 288272eb014SEric Paris { 28963c882a0SEric Paris struct fsnotify_group *group = file->private_data; 290bdae997fSKeith Packard struct user_struct *user = group->inotify_data.user; 291272eb014SEric Paris 29263c882a0SEric Paris fsnotify_clear_marks_by_group(group); 293272eb014SEric Paris 29463c882a0SEric Paris /* free this group, matching get was inotify_init->fsnotify_obtain_group */ 29563c882a0SEric Paris fsnotify_put_group(group); 296272eb014SEric Paris 297bdae997fSKeith Packard atomic_dec(&user->inotify_devs); 298bdae997fSKeith Packard 299272eb014SEric Paris return 0; 300272eb014SEric Paris } 301272eb014SEric Paris 302272eb014SEric Paris static long inotify_ioctl(struct file *file, unsigned int cmd, 303272eb014SEric Paris unsigned long arg) 304272eb014SEric Paris { 30563c882a0SEric Paris struct fsnotify_group *group; 30663c882a0SEric Paris struct fsnotify_event_holder *holder; 30763c882a0SEric Paris struct fsnotify_event *event; 308272eb014SEric Paris void __user *p; 309272eb014SEric Paris int ret = -ENOTTY; 31063c882a0SEric Paris size_t send_len = 0; 311272eb014SEric Paris 31263c882a0SEric Paris group = file->private_data; 313272eb014SEric Paris p = (void __user *) arg; 314272eb014SEric Paris 315272eb014SEric Paris switch (cmd) { 316272eb014SEric Paris case FIONREAD: 31763c882a0SEric Paris mutex_lock(&group->notification_mutex); 31863c882a0SEric Paris list_for_each_entry(holder, &group->notification_list, event_list) { 31963c882a0SEric Paris event = holder->event; 32063c882a0SEric Paris send_len += sizeof(struct inotify_event); 32183cb10f0SEric Paris if (event->name_len) 32283cb10f0SEric Paris send_len += roundup(event->name_len + 1, 32363c882a0SEric Paris sizeof(struct inotify_event)); 32463c882a0SEric Paris } 32563c882a0SEric Paris mutex_unlock(&group->notification_mutex); 32663c882a0SEric Paris ret = put_user(send_len, (int __user *) p); 327272eb014SEric Paris break; 328272eb014SEric Paris } 329272eb014SEric Paris 330272eb014SEric Paris return ret; 331272eb014SEric Paris } 332272eb014SEric Paris 333272eb014SEric Paris static const struct file_operations inotify_fops = { 334272eb014SEric Paris .poll = inotify_poll, 335272eb014SEric Paris .read = inotify_read, 336272eb014SEric Paris .fasync = inotify_fasync, 337272eb014SEric Paris .release = inotify_release, 338272eb014SEric Paris .unlocked_ioctl = inotify_ioctl, 339272eb014SEric Paris .compat_ioctl = inotify_ioctl, 340272eb014SEric Paris }; 341272eb014SEric Paris 342272eb014SEric Paris 34363c882a0SEric Paris /* 34463c882a0SEric Paris * find_inode - resolve a user-given path to a specific inode 34563c882a0SEric Paris */ 34663c882a0SEric Paris static int inotify_find_inode(const char __user *dirname, struct path *path, unsigned flags) 34763c882a0SEric Paris { 34863c882a0SEric Paris int error; 34963c882a0SEric Paris 35063c882a0SEric Paris error = user_path_at(AT_FDCWD, dirname, flags, path); 35163c882a0SEric Paris if (error) 35263c882a0SEric Paris return error; 35363c882a0SEric Paris /* you can only watch an inode if you have read permissions on it */ 35463c882a0SEric Paris error = inode_permission(path->dentry->d_inode, MAY_READ); 35563c882a0SEric Paris if (error) 35663c882a0SEric Paris path_put(path); 35763c882a0SEric Paris return error; 35863c882a0SEric Paris } 35963c882a0SEric Paris 360dead537dSEric Paris /* 361dead537dSEric Paris * Remove the mark from the idr (if present) and drop the reference 362dead537dSEric Paris * on the mark because it was in the idr. 363dead537dSEric Paris */ 3647e790dd5SEric Paris static void inotify_remove_from_idr(struct fsnotify_group *group, 3657e790dd5SEric Paris struct inotify_inode_mark_entry *ientry) 3667e790dd5SEric Paris { 3677e790dd5SEric Paris struct idr *idr; 368dead537dSEric Paris struct fsnotify_mark_entry *entry; 369dead537dSEric Paris struct inotify_inode_mark_entry *found_ientry; 370dead537dSEric Paris int wd; 3717e790dd5SEric Paris 3727e790dd5SEric Paris spin_lock(&group->inotify_data.idr_lock); 3737e790dd5SEric Paris idr = &group->inotify_data.idr; 374dead537dSEric Paris wd = ientry->wd; 375dead537dSEric Paris 376dead537dSEric Paris if (wd == -1) 377dead537dSEric Paris goto out; 378dead537dSEric Paris 379dead537dSEric Paris entry = idr_find(&group->inotify_data.idr, wd); 380dead537dSEric Paris if (unlikely(!entry)) 381dead537dSEric Paris goto out; 382dead537dSEric Paris 383dead537dSEric Paris found_ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); 384dead537dSEric Paris if (unlikely(found_ientry != ientry)) { 385dead537dSEric Paris /* We found an entry in the idr with the right wd, but it's 386dead537dSEric Paris * not the entry we were told to remove. eparis seriously 387dead537dSEric Paris * fucked up somewhere. */ 388dead537dSEric Paris WARN_ON(1); 3897e790dd5SEric Paris ientry->wd = -1; 390dead537dSEric Paris goto out; 3917e790dd5SEric Paris } 392dead537dSEric Paris 393dead537dSEric Paris /* One ref for being in the idr, one ref held by the caller */ 394dead537dSEric Paris BUG_ON(atomic_read(&entry->refcnt) < 2); 395dead537dSEric Paris 396dead537dSEric Paris idr_remove(idr, wd); 397dead537dSEric Paris ientry->wd = -1; 398dead537dSEric Paris 399dead537dSEric Paris /* removed from the idr, drop that ref */ 400dead537dSEric Paris fsnotify_put_mark(entry); 401dead537dSEric Paris out: 402dead537dSEric Paris spin_unlock(&group->inotify_data.idr_lock); 403dead537dSEric Paris } 404dead537dSEric Paris 40563c882a0SEric Paris /* 406dead537dSEric Paris * Send IN_IGNORED for this wd, remove this wd from the idr. 40763c882a0SEric Paris */ 408528da3e9SEric Paris void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, 409528da3e9SEric Paris struct fsnotify_group *group) 41063c882a0SEric Paris { 41163c882a0SEric Paris struct inotify_inode_mark_entry *ientry; 412f44aebccSEric Paris struct fsnotify_event *ignored_event; 41363c882a0SEric Paris struct inotify_event_private_data *event_priv; 41463c882a0SEric Paris struct fsnotify_event_private_data *fsn_event_priv; 415eef3a116SEric Paris int ret; 41663c882a0SEric Paris 417f44aebccSEric Paris ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL, 418f44aebccSEric Paris FSNOTIFY_EVENT_NONE, NULL, 0, 419f44aebccSEric Paris GFP_NOFS); 420f44aebccSEric Paris if (!ignored_event) 421f44aebccSEric Paris return; 422f44aebccSEric Paris 42363c882a0SEric Paris ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); 42463c882a0SEric Paris 425f44aebccSEric Paris event_priv = kmem_cache_alloc(event_priv_cachep, GFP_NOFS); 42663c882a0SEric Paris if (unlikely(!event_priv)) 42763c882a0SEric Paris goto skip_send_ignore; 42863c882a0SEric Paris 42963c882a0SEric Paris fsn_event_priv = &event_priv->fsnotify_event_priv_data; 43063c882a0SEric Paris 43163c882a0SEric Paris fsn_event_priv->group = group; 43263c882a0SEric Paris event_priv->wd = ientry->wd; 43363c882a0SEric Paris 434eef3a116SEric Paris ret = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv); 435eef3a116SEric Paris if (ret) 43663c882a0SEric Paris inotify_free_event_priv(fsn_event_priv); 43763c882a0SEric Paris 43863c882a0SEric Paris skip_send_ignore: 43963c882a0SEric Paris 440f44aebccSEric Paris /* matches the reference taken when the event was created */ 441f44aebccSEric Paris fsnotify_put_event(ignored_event); 442f44aebccSEric Paris 44363c882a0SEric Paris /* remove this entry from the idr */ 4447e790dd5SEric Paris inotify_remove_from_idr(group, ientry); 44563c882a0SEric Paris 4465549f7cdSEric Paris atomic_dec(&group->inotify_data.user->inotify_watches); 44763c882a0SEric Paris } 44863c882a0SEric Paris 44963c882a0SEric Paris /* ding dong the mark is dead */ 45063c882a0SEric Paris static void inotify_free_mark(struct fsnotify_mark_entry *entry) 45163c882a0SEric Paris { 45263c882a0SEric Paris struct inotify_inode_mark_entry *ientry = (struct inotify_inode_mark_entry *)entry; 45363c882a0SEric Paris 45463c882a0SEric Paris kmem_cache_free(inotify_inode_mark_cachep, ientry); 45563c882a0SEric Paris } 45663c882a0SEric Paris 45752cef755SEric Paris static int inotify_update_existing_watch(struct fsnotify_group *group, 45852cef755SEric Paris struct inode *inode, 45952cef755SEric Paris u32 arg) 46063c882a0SEric Paris { 46152cef755SEric Paris struct fsnotify_mark_entry *entry; 46263c882a0SEric Paris struct inotify_inode_mark_entry *ientry; 46363c882a0SEric Paris __u32 old_mask, new_mask; 46452cef755SEric Paris __u32 mask; 46552cef755SEric Paris int add = (arg & IN_MASK_ADD); 46652cef755SEric Paris int ret; 46763c882a0SEric Paris 46863c882a0SEric Paris /* don't allow invalid bits: we don't want flags set */ 46963c882a0SEric Paris mask = inotify_arg_to_mask(arg); 47063c882a0SEric Paris if (unlikely(!mask)) 47163c882a0SEric Paris return -EINVAL; 47263c882a0SEric Paris 47363c882a0SEric Paris spin_lock(&inode->i_lock); 47463c882a0SEric Paris entry = fsnotify_find_mark_entry(group, inode); 47563c882a0SEric Paris spin_unlock(&inode->i_lock); 47652cef755SEric Paris if (!entry) 47752cef755SEric Paris return -ENOENT; 47852cef755SEric Paris 47963c882a0SEric Paris ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); 48075fe2b26SEric Paris 48163c882a0SEric Paris spin_lock(&entry->lock); 48263c882a0SEric Paris 48363c882a0SEric Paris old_mask = entry->mask; 48463c882a0SEric Paris if (add) { 48563c882a0SEric Paris entry->mask |= mask; 48663c882a0SEric Paris new_mask = entry->mask; 48763c882a0SEric Paris } else { 48863c882a0SEric Paris entry->mask = mask; 48963c882a0SEric Paris new_mask = entry->mask; 49063c882a0SEric Paris } 49163c882a0SEric Paris 49263c882a0SEric Paris spin_unlock(&entry->lock); 49363c882a0SEric Paris 49463c882a0SEric Paris if (old_mask != new_mask) { 49563c882a0SEric Paris /* more bits in old than in new? */ 49663c882a0SEric Paris int dropped = (old_mask & ~new_mask); 49763c882a0SEric Paris /* more bits in this entry than the inode's mask? */ 49863c882a0SEric Paris int do_inode = (new_mask & ~inode->i_fsnotify_mask); 49963c882a0SEric Paris /* more bits in this entry than the group? */ 50063c882a0SEric Paris int do_group = (new_mask & ~group->mask); 50163c882a0SEric Paris 50263c882a0SEric Paris /* update the inode with this new entry */ 50363c882a0SEric Paris if (dropped || do_inode) 50463c882a0SEric Paris fsnotify_recalc_inode_mask(inode); 50563c882a0SEric Paris 50663c882a0SEric Paris /* update the group mask with the new mask */ 50763c882a0SEric Paris if (dropped || do_group) 50863c882a0SEric Paris fsnotify_recalc_group_mask(group); 50963c882a0SEric Paris } 51063c882a0SEric Paris 51152cef755SEric Paris /* return the wd */ 51252cef755SEric Paris ret = ientry->wd; 51352cef755SEric Paris 51452cef755SEric Paris /* match the get from fsnotify_find_mark_entry() */ 51575fe2b26SEric Paris fsnotify_put_mark(entry); 51675fe2b26SEric Paris 51752cef755SEric Paris return ret; 51863c882a0SEric Paris } 5197e790dd5SEric Paris 52052cef755SEric Paris static int inotify_new_watch(struct fsnotify_group *group, 52152cef755SEric Paris struct inode *inode, 52252cef755SEric Paris u32 arg) 52352cef755SEric Paris { 52452cef755SEric Paris struct inotify_inode_mark_entry *tmp_ientry; 52552cef755SEric Paris __u32 mask; 52652cef755SEric Paris int ret; 52752cef755SEric Paris 52852cef755SEric Paris /* don't allow invalid bits: we don't want flags set */ 52952cef755SEric Paris mask = inotify_arg_to_mask(arg); 53052cef755SEric Paris if (unlikely(!mask)) 53152cef755SEric Paris return -EINVAL; 53252cef755SEric Paris 53352cef755SEric Paris tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); 53452cef755SEric Paris if (unlikely(!tmp_ientry)) 53552cef755SEric Paris return -ENOMEM; 53652cef755SEric Paris 53752cef755SEric Paris fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark); 53852cef755SEric Paris tmp_ientry->fsn_entry.mask = mask; 53952cef755SEric Paris tmp_ientry->wd = -1; 54052cef755SEric Paris 54152cef755SEric Paris ret = -ENOSPC; 54252cef755SEric Paris if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) 54352cef755SEric Paris goto out_err; 54452cef755SEric Paris retry: 54552cef755SEric Paris ret = -ENOMEM; 54652cef755SEric Paris if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL))) 54752cef755SEric Paris goto out_err; 54852cef755SEric Paris 54952cef755SEric Paris spin_lock(&group->inotify_data.idr_lock); 55052cef755SEric Paris ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry, 5519e572cc9SEric Paris group->inotify_data.last_wd+1, 55252cef755SEric Paris &tmp_ientry->wd); 55352cef755SEric Paris spin_unlock(&group->inotify_data.idr_lock); 55452cef755SEric Paris if (ret) { 55552cef755SEric Paris /* idr was out of memory allocate and try again */ 55652cef755SEric Paris if (ret == -EAGAIN) 55752cef755SEric Paris goto retry; 55852cef755SEric Paris goto out_err; 55952cef755SEric Paris } 56052cef755SEric Paris 561dead537dSEric Paris /* we put the mark on the idr, take a reference */ 562dead537dSEric Paris fsnotify_get_mark(&tmp_ientry->fsn_entry); 563dead537dSEric Paris 56452cef755SEric Paris /* we are on the idr, now get on the inode */ 56552cef755SEric Paris ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode); 56652cef755SEric Paris if (ret) { 56752cef755SEric Paris /* we failed to get on the inode, get off the idr */ 56852cef755SEric Paris inotify_remove_from_idr(group, tmp_ientry); 56952cef755SEric Paris goto out_err; 57052cef755SEric Paris } 57152cef755SEric Paris 57252cef755SEric Paris /* update the idr hint, who cares about races, it's just a hint */ 57352cef755SEric Paris group->inotify_data.last_wd = tmp_ientry->wd; 57452cef755SEric Paris 57552cef755SEric Paris /* increment the number of watches the user has */ 57652cef755SEric Paris atomic_inc(&group->inotify_data.user->inotify_watches); 57752cef755SEric Paris 57852cef755SEric Paris /* return the watch descriptor for this new entry */ 57952cef755SEric Paris ret = tmp_ientry->wd; 58052cef755SEric Paris 581750a8870SEric Paris /* if this mark added a new event update the group mask */ 582750a8870SEric Paris if (mask & ~group->mask) 583750a8870SEric Paris fsnotify_recalc_group_mask(group); 584750a8870SEric Paris 58552cef755SEric Paris out_err: 586*3dbc6fb6SEric Paris /* match the ref from fsnotify_init_markentry() */ 587*3dbc6fb6SEric Paris fsnotify_put_mark(&tmp_ientry->fsn_entry); 58852cef755SEric Paris 58952cef755SEric Paris return ret; 59052cef755SEric Paris } 59152cef755SEric Paris 59252cef755SEric Paris static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) 59352cef755SEric Paris { 59452cef755SEric Paris int ret = 0; 59552cef755SEric Paris 59652cef755SEric Paris retry: 59752cef755SEric Paris /* try to update and existing watch with the new arg */ 59852cef755SEric Paris ret = inotify_update_existing_watch(group, inode, arg); 59952cef755SEric Paris /* no mark present, try to add a new one */ 60052cef755SEric Paris if (ret == -ENOENT) 60152cef755SEric Paris ret = inotify_new_watch(group, inode, arg); 60252cef755SEric Paris /* 60352cef755SEric Paris * inotify_new_watch could race with another thread which did an 60452cef755SEric Paris * inotify_new_watch between the update_existing and the add watch 60552cef755SEric Paris * here, go back and try to update an existing mark again. 60652cef755SEric Paris */ 60752cef755SEric Paris if (ret == -EEXIST) 60852cef755SEric Paris goto retry; 60952cef755SEric Paris 61063c882a0SEric Paris return ret; 61163c882a0SEric Paris } 61263c882a0SEric Paris 61363c882a0SEric Paris static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsigned int max_events) 61463c882a0SEric Paris { 61563c882a0SEric Paris struct fsnotify_group *group; 61663c882a0SEric Paris unsigned int grp_num; 61763c882a0SEric Paris 61863c882a0SEric Paris /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ 61963c882a0SEric Paris grp_num = (INOTIFY_GROUP_NUM - atomic_inc_return(&inotify_grp_num)); 62063c882a0SEric Paris group = fsnotify_obtain_group(grp_num, 0, &inotify_fsnotify_ops); 62163c882a0SEric Paris if (IS_ERR(group)) 62263c882a0SEric Paris return group; 62363c882a0SEric Paris 62463c882a0SEric Paris group->max_events = max_events; 62563c882a0SEric Paris 62663c882a0SEric Paris spin_lock_init(&group->inotify_data.idr_lock); 62763c882a0SEric Paris idr_init(&group->inotify_data.idr); 6289e572cc9SEric Paris group->inotify_data.last_wd = 0; 62963c882a0SEric Paris group->inotify_data.user = user; 63063c882a0SEric Paris group->inotify_data.fa = NULL; 63163c882a0SEric Paris 63263c882a0SEric Paris return group; 63363c882a0SEric Paris } 63463c882a0SEric Paris 63563c882a0SEric Paris 63663c882a0SEric Paris /* inotify syscalls */ 637938bb9f5SHeiko Carstens SYSCALL_DEFINE1(inotify_init1, int, flags) 638272eb014SEric Paris { 63963c882a0SEric Paris struct fsnotify_group *group; 640272eb014SEric Paris struct user_struct *user; 641c44dcc56SAl Viro int ret; 642272eb014SEric Paris 643272eb014SEric Paris /* Check the IN_* constants for consistency. */ 644272eb014SEric Paris BUILD_BUG_ON(IN_CLOEXEC != O_CLOEXEC); 645272eb014SEric Paris BUILD_BUG_ON(IN_NONBLOCK != O_NONBLOCK); 646272eb014SEric Paris 647272eb014SEric Paris if (flags & ~(IN_CLOEXEC | IN_NONBLOCK)) 648272eb014SEric Paris return -EINVAL; 649272eb014SEric Paris 650272eb014SEric Paris user = get_current_user(); 651272eb014SEric Paris if (unlikely(atomic_read(&user->inotify_devs) >= 652272eb014SEric Paris inotify_max_user_instances)) { 653272eb014SEric Paris ret = -EMFILE; 654272eb014SEric Paris goto out_free_uid; 655272eb014SEric Paris } 656272eb014SEric Paris 65763c882a0SEric Paris /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ 65863c882a0SEric Paris group = inotify_new_group(user, inotify_max_queued_events); 65963c882a0SEric Paris if (IS_ERR(group)) { 66063c882a0SEric Paris ret = PTR_ERR(group); 661272eb014SEric Paris goto out_free_uid; 662272eb014SEric Paris } 663272eb014SEric Paris 664825f9692SAl Viro atomic_inc(&user->inotify_devs); 665825f9692SAl Viro 666c44dcc56SAl Viro ret = anon_inode_getfd("inotify", &inotify_fops, group, 667c44dcc56SAl Viro O_RDONLY | flags); 668c44dcc56SAl Viro if (ret >= 0) 669c44dcc56SAl Viro return ret; 670825f9692SAl Viro 671825f9692SAl Viro atomic_dec(&user->inotify_devs); 672272eb014SEric Paris out_free_uid: 673272eb014SEric Paris free_uid(user); 674272eb014SEric Paris return ret; 675272eb014SEric Paris } 676272eb014SEric Paris 677938bb9f5SHeiko Carstens SYSCALL_DEFINE0(inotify_init) 678272eb014SEric Paris { 679272eb014SEric Paris return sys_inotify_init1(0); 680272eb014SEric Paris } 681272eb014SEric Paris 6822e4d0924SHeiko Carstens SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname, 6832e4d0924SHeiko Carstens u32, mask) 684272eb014SEric Paris { 68563c882a0SEric Paris struct fsnotify_group *group; 686272eb014SEric Paris struct inode *inode; 687272eb014SEric Paris struct path path; 688272eb014SEric Paris struct file *filp; 689272eb014SEric Paris int ret, fput_needed; 690272eb014SEric Paris unsigned flags = 0; 691272eb014SEric Paris 692272eb014SEric Paris filp = fget_light(fd, &fput_needed); 693272eb014SEric Paris if (unlikely(!filp)) 694272eb014SEric Paris return -EBADF; 695272eb014SEric Paris 696272eb014SEric Paris /* verify that this is indeed an inotify instance */ 697272eb014SEric Paris if (unlikely(filp->f_op != &inotify_fops)) { 698272eb014SEric Paris ret = -EINVAL; 699272eb014SEric Paris goto fput_and_out; 700272eb014SEric Paris } 701272eb014SEric Paris 702272eb014SEric Paris if (!(mask & IN_DONT_FOLLOW)) 703272eb014SEric Paris flags |= LOOKUP_FOLLOW; 704272eb014SEric Paris if (mask & IN_ONLYDIR) 705272eb014SEric Paris flags |= LOOKUP_DIRECTORY; 706272eb014SEric Paris 70763c882a0SEric Paris ret = inotify_find_inode(pathname, &path, flags); 70863c882a0SEric Paris if (ret) 709272eb014SEric Paris goto fput_and_out; 710272eb014SEric Paris 71163c882a0SEric Paris /* inode held in place by reference to path; group by fget on fd */ 712272eb014SEric Paris inode = path.dentry->d_inode; 71363c882a0SEric Paris group = filp->private_data; 714272eb014SEric Paris 71563c882a0SEric Paris /* create/update an inode mark */ 71663c882a0SEric Paris ret = inotify_update_watch(group, inode, mask); 717272eb014SEric Paris path_put(&path); 718272eb014SEric Paris fput_and_out: 719272eb014SEric Paris fput_light(filp, fput_needed); 720272eb014SEric Paris return ret; 721272eb014SEric Paris } 722272eb014SEric Paris 7232e4d0924SHeiko Carstens SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) 724272eb014SEric Paris { 72563c882a0SEric Paris struct fsnotify_group *group; 72663c882a0SEric Paris struct fsnotify_mark_entry *entry; 727272eb014SEric Paris struct file *filp; 72863c882a0SEric Paris int ret = 0, fput_needed; 729272eb014SEric Paris 730272eb014SEric Paris filp = fget_light(fd, &fput_needed); 731272eb014SEric Paris if (unlikely(!filp)) 732272eb014SEric Paris return -EBADF; 733272eb014SEric Paris 734272eb014SEric Paris /* verify that this is indeed an inotify instance */ 735272eb014SEric Paris if (unlikely(filp->f_op != &inotify_fops)) { 736272eb014SEric Paris ret = -EINVAL; 737272eb014SEric Paris goto out; 738272eb014SEric Paris } 739272eb014SEric Paris 74063c882a0SEric Paris group = filp->private_data; 741272eb014SEric Paris 74263c882a0SEric Paris spin_lock(&group->inotify_data.idr_lock); 74363c882a0SEric Paris entry = idr_find(&group->inotify_data.idr, wd); 74463c882a0SEric Paris if (unlikely(!entry)) { 74563c882a0SEric Paris spin_unlock(&group->inotify_data.idr_lock); 74663c882a0SEric Paris ret = -EINVAL; 74763c882a0SEric Paris goto out; 74863c882a0SEric Paris } 74963c882a0SEric Paris fsnotify_get_mark(entry); 75063c882a0SEric Paris spin_unlock(&group->inotify_data.idr_lock); 75163c882a0SEric Paris 752528da3e9SEric Paris fsnotify_destroy_mark_by_entry(entry); 75363c882a0SEric Paris fsnotify_put_mark(entry); 754272eb014SEric Paris 755272eb014SEric Paris out: 756272eb014SEric Paris fput_light(filp, fput_needed); 757272eb014SEric Paris return ret; 758272eb014SEric Paris } 759272eb014SEric Paris 760272eb014SEric Paris /* 761272eb014SEric Paris * inotify_user_setup - Our initialization function. Note that we cannnot return 762272eb014SEric Paris * error because we have compiled-in VFS hooks. So an (unlikely) failure here 763272eb014SEric Paris * must result in panic(). 764272eb014SEric Paris */ 765272eb014SEric Paris static int __init inotify_user_setup(void) 766272eb014SEric Paris { 76763c882a0SEric Paris inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark_entry, SLAB_PANIC); 76863c882a0SEric Paris event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC); 76963c882a0SEric Paris 770272eb014SEric Paris inotify_max_queued_events = 16384; 771272eb014SEric Paris inotify_max_user_instances = 128; 772272eb014SEric Paris inotify_max_user_watches = 8192; 773272eb014SEric Paris 774272eb014SEric Paris return 0; 775272eb014SEric Paris } 776272eb014SEric Paris module_init(inotify_user_setup); 777