| /* |
| * fs/inotify_user.c - inotify support for userspace |
| * |
| * Authors: |
| * John McCutchan <ttb@tentacle.dhs.org> |
| * Robert Love <rml@novell.com> |
| * |
| * Copyright (C) 2005 John McCutchan |
| * Copyright 2006 Hewlett-Packard Development Company, L.P. |
| * |
| * Copyright (C) 2009 Eric Paris <Red Hat Inc> |
| * inotify was largely rewriten to make use of the fsnotify infrastructure |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the |
| * Free Software Foundation; either version 2, or (at your option) any |
| * later version. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| */ |
| |
| #include <linux/file.h> |
| #include <linux/fs.h> /* struct inode */ |
| #include <linux/fsnotify_backend.h> |
| #include <linux/idr.h> |
| #include <linux/init.h> /* fs_initcall */ |
| #include <linux/inotify.h> |
| #include <linux/kernel.h> /* roundup() */ |
| #include <linux/namei.h> /* LOOKUP_FOLLOW */ |
| #include <linux/sched/signal.h> |
| #include <linux/slab.h> /* struct kmem_cache */ |
| #include <linux/syscalls.h> |
| #include <linux/types.h> |
| #include <linux/anon_inodes.h> |
| #include <linux/uaccess.h> |
| #include <linux/poll.h> |
| #include <linux/wait.h> |
| |
| #include "inotify.h" |
| #include "../fdinfo.h" |
| |
| #include <asm/ioctls.h> |
| |
| /* configurable via /proc/sys/fs/inotify/ */ |
| static int inotify_max_queued_events __read_mostly; |
| |
| struct kmem_cache *inotify_inode_mark_cachep __read_mostly; |
| |
| #ifdef CONFIG_SYSCTL |
| |
| #include <linux/sysctl.h> |
| |
| static int zero; |
| |
| struct ctl_table inotify_table[] = { |
| { |
| .procname = "max_user_instances", |
| .data = &init_user_ns.ucount_max[UCOUNT_INOTIFY_INSTANCES], |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_minmax, |
| .extra1 = &zero, |
| }, |
| { |
| .procname = "max_user_watches", |
| .data = &init_user_ns.ucount_max[UCOUNT_INOTIFY_WATCHES], |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_minmax, |
| .extra1 = &zero, |
| }, |
| { |
| .procname = "max_queued_events", |
| .data = &inotify_max_queued_events, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_minmax, |
| .extra1 = &zero |
| }, |
| { } |
| }; |
| #endif /* CONFIG_SYSCTL */ |
| |
| static inline __u32 inotify_arg_to_mask(u32 arg) |
| { |
| __u32 mask; |
| |
| /* |
| * everything should accept their own ignored, cares about children, |
| * and should receive events when the inode is unmounted |
| */ |
| mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD | FS_UNMOUNT); |
| |
| /* mask off the flags used to open the fd */ |
| mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT | IN_EXCL_UNLINK)); |
| |
| return mask; |
| } |
| |
| static inline u32 inotify_mask_to_arg(__u32 mask) |
| { |
| return mask & (IN_ALL_EVENTS | IN_ISDIR | IN_UNMOUNT | IN_IGNORED | |
| IN_Q_OVERFLOW); |
| } |
| |
| /* intofiy userspace file descriptor functions */ |
| static __poll_t inotify_poll(struct file *file, poll_table *wait) |
| { |
| struct fsnotify_group *group = file->private_data; |
| __poll_t ret = 0; |
| |
| poll_wait(file, &group->notification_waitq, wait); |
| spin_lock(&group->notification_lock); |
| if (!fsnotify_notify_queue_is_empty(group)) |
| ret = EPOLLIN | EPOLLRDNORM; |
| spin_unlock(&group->notification_lock); |
| |
| return ret; |
| } |
| |
| static int round_event_name_len(struct fsnotify_event *fsn_event) |
| { |
| struct inotify_event_info *event; |
| |
| event = INOTIFY_E(fsn_event); |
| if (!event->name_len) |
| return 0; |
| return roundup(event->name_len + 1, sizeof(struct inotify_event)); |
| } |
| |
| /* |
| * Get an inotify_kernel_event if one exists and is small |
| * enough to fit in "count". Return an error pointer if |
| * not large enough. |
| * |
| * Called with the group->notification_lock held. |
| */ |
| static struct fsnotify_event *get_one_event(struct fsnotify_group *group, |
| size_t count) |
| { |
| size_t event_size = sizeof(struct inotify_event); |
| struct fsnotify_event *event; |
| |
| if (fsnotify_notify_queue_is_empty(group)) |
| return NULL; |
| |
| event = fsnotify_peek_first_event(group); |
| |
| pr_debug("%s: group=%p event=%p\n", __func__, group, event); |
| |
| event_size += round_event_name_len(event); |
| if (event_size > count) |
| return ERR_PTR(-EINVAL); |
| |
| /* held the notification_lock the whole time, so this is the |
| * same event we peeked above */ |
| fsnotify_remove_first_event(group); |
| |
| return event; |
| } |
| |
| /* |
| * Copy an event to user space, returning how much we copied. |
| * |
| * We already checked that the event size is smaller than the |
| * buffer we had in "get_one_event()" above. |
| */ |
| static ssize_t copy_event_to_user(struct fsnotify_group *group, |
| struct fsnotify_event *fsn_event, |
| char __user *buf) |
| { |
| struct inotify_event inotify_event; |
| struct inotify_event_info *event; |
| size_t event_size = sizeof(struct inotify_event); |
| size_t name_len; |
| size_t pad_name_len; |
| |
| pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event); |
| |
| event = INOTIFY_E(fsn_event); |
| name_len = event->name_len; |
| /* |
| * round up name length so it is a multiple of event_size |
| * plus an extra byte for the terminating '\0'. |
| */ |
| pad_name_len = round_event_name_len(fsn_event); |
| inotify_event.len = pad_name_len; |
| inotify_event.mask = inotify_mask_to_arg(fsn_event->mask); |
| inotify_event.wd = event->wd; |
| inotify_event.cookie = event->sync_cookie; |
| |
| /* send the main event */ |
| if (copy_to_user(buf, &inotify_event, event_size)) |
| return -EFAULT; |
| |
| buf += event_size; |
| |
| /* |
| * fsnotify only stores the pathname, so here we have to send the pathname |
| * and then pad that pathname out to a multiple of sizeof(inotify_event) |
| * with zeros. |
| */ |
| if (pad_name_len) { |
| /* copy the path name */ |
| if (copy_to_user(buf, event->name, name_len)) |
| return -EFAULT; |
| buf += name_len; |
| |
| /* fill userspace with 0's */ |
| if (clear_user(buf, pad_name_len - name_len)) |
| return -EFAULT; |
| event_size += pad_name_len; |
| } |
| |
| return event_size; |
| } |
| |
| static ssize_t inotify_read(struct file *file, char __user *buf, |
| size_t count, loff_t *pos) |
| { |
| struct fsnotify_group *group; |
| struct fsnotify_event *kevent; |
| char __user *start; |
| int ret; |
| DEFINE_WAIT_FUNC(wait, woken_wake_function); |
| |
| start = buf; |
| group = file->private_data; |
| |
| add_wait_queue(&group->notification_waitq, &wait); |
| while (1) { |
| spin_lock(&group->notification_lock); |
| kevent = get_one_event(group, count); |
| spin_unlock(&group->notification_lock); |
| |
| pr_debug("%s: group=%p kevent=%p\n", __func__, group, kevent); |
| |
| if (kevent) { |
| ret = PTR_ERR(kevent); |
| if (IS_ERR(kevent)) |
| break; |
| ret = copy_event_to_user(group, kevent, buf); |
| fsnotify_destroy_event(group, kevent); |
| if (ret < 0) |
| break; |
| buf += ret; |
| count -= ret; |
| continue; |
| } |
| |
| ret = -EAGAIN; |
| if (file->f_flags & O_NONBLOCK) |
| break; |
| ret = -ERESTARTSYS; |
| if (signal_pending(current)) |
| break; |
| |
| if (start != buf) |
| break; |
| |
| wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
| } |
| remove_wait_queue(&group->notification_waitq, &wait); |
| |
| if (start != buf && ret != -EFAULT) |
| ret = buf - start; |
| return ret; |
| } |
| |
| static int inotify_release(struct inode *ignored, struct file *file) |
| { |
| struct fsnotify_group *group = file->private_data; |
| |
| pr_debug("%s: group=%p\n", __func__, group); |
| |
| /* free this group, matching get was inotify_init->fsnotify_obtain_group */ |
| fsnotify_destroy_group(group); |
| |
| return 0; |
| } |
| |
| static long inotify_ioctl(struct file *file, unsigned int cmd, |
| unsigned long arg) |
| { |
| struct fsnotify_group *group; |
| struct fsnotify_event *fsn_event; |
| void __user *p; |
| int ret = -ENOTTY; |
| size_t send_len = 0; |
| |
| group = file->private_data; |
| p = (void __user *) arg; |
| |
| pr_debug("%s: group=%p cmd=%u\n", __func__, group, cmd); |
| |
| switch (cmd) { |
| case FIONREAD: |
| spin_lock(&group->notification_lock); |
| list_for_each_entry(fsn_event, &group->notification_list, |
| list) { |
| send_len += sizeof(struct inotify_event); |
| send_len += round_event_name_len(fsn_event); |
| } |
| spin_unlock(&group->notification_lock); |
| ret = put_user(send_len, (int __user *) p); |
| break; |
| #ifdef CONFIG_CHECKPOINT_RESTORE |
| case INOTIFY_IOC_SETNEXTWD: |
| ret = -EINVAL; |
| if (arg >= 1 && arg <= INT_MAX) { |
| struct inotify_group_private_data *data; |
| |
| data = &group->inotify_data; |
| spin_lock(&data->idr_lock); |
| idr_set_cursor(&data->idr, (unsigned int)arg); |
| spin_unlock(&data->idr_lock); |
| ret = 0; |
| } |
| break; |
| #endif /* CONFIG_CHECKPOINT_RESTORE */ |
| } |
| |
| return ret; |
| } |
| |
| static const struct file_operations inotify_fops = { |
| .show_fdinfo = inotify_show_fdinfo, |
| .poll = inotify_poll, |
| .read = inotify_read, |
| .fasync = fsnotify_fasync, |
| .release = inotify_release, |
| .unlocked_ioctl = inotify_ioctl, |
| .compat_ioctl = inotify_ioctl, |
| .llseek = noop_llseek, |
| }; |
| |
| |
| /* |
| * find_inode - resolve a user-given path to a specific inode |
| */ |
| static int inotify_find_inode(const char __user *dirname, struct path *path, unsigned flags) |
| { |
| int error; |
| |
| error = user_path_at(AT_FDCWD, dirname, flags, path); |
| if (error) |
| return error; |
| /* you can only watch an inode if you have read permissions on it */ |
| error = inode_permission(path->dentry->d_inode, MAY_READ); |
| if (error) |
| path_put(path); |
| return error; |
| } |
| |
| static int inotify_add_to_idr(struct idr *idr, spinlock_t *idr_lock, |
| struct inotify_inode_mark *i_mark) |
| { |
| int ret; |
| |
| idr_preload(GFP_KERNEL); |
| spin_lock(idr_lock); |
| |
| ret = idr_alloc_cyclic(idr, i_mark, 1, 0, GFP_NOWAIT); |
| if (ret >= 0) { |
| /* we added the mark to the idr, take a reference */ |
| i_mark->wd = ret; |
| fsnotify_get_mark(&i_mark->fsn_mark); |
| } |
| |
| spin_unlock(idr_lock); |
| idr_preload_end(); |
| return ret < 0 ? ret : 0; |
| } |
| |
| static struct inotify_inode_mark *inotify_idr_find_locked(struct fsnotify_group *group, |
| int wd) |
| { |
| struct idr *idr = &group->inotify_data.idr; |
| spinlock_t *idr_lock = &group->inotify_data.idr_lock; |
| struct inotify_inode_mark *i_mark; |
| |
| assert_spin_locked(idr_lock); |
| |
| i_mark = idr_find(idr, wd); |
| if (i_mark) { |
| struct fsnotify_mark *fsn_mark = &i_mark->fsn_mark; |
| |
| fsnotify_get_mark(fsn_mark); |
| /* One ref for being in the idr, one ref we just took */ |
| BUG_ON(refcount_read(&fsn_mark->refcnt) < 2); |
| } |
| |
| return i_mark; |
| } |
| |
| static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group, |
| int wd) |
| { |
| struct inotify_inode_mark *i_mark; |
| spinlock_t *idr_lock = &group->inotify_data.idr_lock; |
| |
| spin_lock(idr_lock); |
| i_mark = inotify_idr_find_locked(group, wd); |
| spin_unlock(idr_lock); |
| |
| return i_mark; |
| } |
| |
| /* |
| * Remove the mark from the idr (if present) and drop the reference |
| * on the mark because it was in the idr. |
| */ |
| static void inotify_remove_from_idr(struct fsnotify_group *group, |
| struct inotify_inode_mark *i_mark) |
| { |
| struct idr *idr = &group->inotify_data.idr; |
| spinlock_t *idr_lock = &group->inotify_data.idr_lock; |
| struct inotify_inode_mark *found_i_mark = NULL; |
| int wd; |
| |
| spin_lock(idr_lock); |
| wd = i_mark->wd; |
| |
| /* |
| * does this i_mark think it is in the idr? we shouldn't get called |
| * if it wasn't.... |
| */ |
| if (wd == -1) { |
| WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p\n", |
| __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group); |
| goto out; |
| } |
| |
| /* Lets look in the idr to see if we find it */ |
| found_i_mark = inotify_idr_find_locked(group, wd); |
| if (unlikely(!found_i_mark)) { |
| WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p\n", |
| __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group); |
| goto out; |
| } |
| |
| /* |
| * We found an mark in the idr at the right wd, but it's |
| * not the mark we were told to remove. eparis seriously |
| * fucked up somewhere. |
| */ |
| if (unlikely(found_i_mark != i_mark)) { |
| WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p " |
| "found_i_mark=%p found_i_mark->wd=%d " |
| "found_i_mark->group=%p\n", __func__, i_mark, |
| i_mark->wd, i_mark->fsn_mark.group, found_i_mark, |
| found_i_mark->wd, found_i_mark->fsn_mark.group); |
| goto out; |
| } |
| |
| /* |
| * One ref for being in the idr |
| * one ref grabbed by inotify_idr_find |
| */ |
| if (unlikely(refcount_read(&i_mark->fsn_mark.refcnt) < 2)) { |
| printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p\n", |
| __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group); |
| /* we can't really recover with bad ref cnting.. */ |
| BUG(); |
| } |
| |
| idr_remove(idr, wd); |
| /* Removed from the idr, drop that ref. */ |
| fsnotify_put_mark(&i_mark->fsn_mark); |
| out: |
| i_mark->wd = -1; |
| spin_unlock(idr_lock); |
| /* match the ref taken by inotify_idr_find_locked() */ |
| if (found_i_mark) |
| fsnotify_put_mark(&found_i_mark->fsn_mark); |
| } |
| |
| /* |
| * Send IN_IGNORED for this wd, remove this wd from the idr. |
| */ |
| void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, |
| struct fsnotify_group *group) |
| { |
| struct inotify_inode_mark *i_mark; |
| struct fsnotify_iter_info iter_info = { }; |
| |
| fsnotify_iter_set_report_type_mark(&iter_info, FSNOTIFY_OBJ_TYPE_INODE, |
| fsn_mark); |
| |
| /* Queue ignore event for the watch */ |
| inotify_handle_event(group, NULL, FS_IN_IGNORED, NULL, |
| FSNOTIFY_EVENT_NONE, NULL, 0, &iter_info); |
| |
| i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); |
| /* remove this mark from the idr */ |
| inotify_remove_from_idr(group, i_mark); |
| |
| dec_inotify_watches(group->inotify_data.ucounts); |
| } |
| |
| static int inotify_update_existing_watch(struct fsnotify_group *group, |
| struct inode *inode, |
| u32 arg) |
| { |
| struct fsnotify_mark *fsn_mark; |
| struct inotify_inode_mark *i_mark; |
| __u32 old_mask, new_mask; |
| __u32 mask; |
| int add = (arg & IN_MASK_ADD); |
| int ret; |
| |
| mask = inotify_arg_to_mask(arg); |
| |
| fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group); |
| if (!fsn_mark) |
| return -ENOENT; |
| |
| i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); |
| |
| spin_lock(&fsn_mark->lock); |
| old_mask = fsn_mark->mask; |
| if (add) |
| fsn_mark->mask |= mask; |
| else |
| fsn_mark->mask = mask; |
| new_mask = fsn_mark->mask; |
| spin_unlock(&fsn_mark->lock); |
| |
| if (old_mask != new_mask) { |
| /* more bits in old than in new? */ |
| int dropped = (old_mask & ~new_mask); |
| /* more bits in this fsn_mark than the inode's mask? */ |
| int do_inode = (new_mask & ~inode->i_fsnotify_mask); |
| |
| /* update the inode with this new fsn_mark */ |
| if (dropped || do_inode) |
| fsnotify_recalc_mask(inode->i_fsnotify_marks); |
| |
| } |
| |
| /* return the wd */ |
| ret = i_mark->wd; |
| |
| /* match the get from fsnotify_find_mark() */ |
| fsnotify_put_mark(fsn_mark); |
| |
| return ret; |
| } |
| |
| static int inotify_new_watch(struct fsnotify_group *group, |
| struct inode *inode, |
| u32 arg) |
| { |
| struct inotify_inode_mark *tmp_i_mark; |
| __u32 mask; |
| int ret; |
| struct idr *idr = &group->inotify_data.idr; |
| spinlock_t *idr_lock = &group->inotify_data.idr_lock; |
| |
| mask = inotify_arg_to_mask(arg); |
| |
| tmp_i_mark = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); |
| if (unlikely(!tmp_i_mark)) |
| return -ENOMEM; |
| |
| fsnotify_init_mark(&tmp_i_mark->fsn_mark, group); |
| tmp_i_mark->fsn_mark.mask = mask; |
| tmp_i_mark->wd = -1; |
| |
| ret = inotify_add_to_idr(idr, idr_lock, tmp_i_mark); |
| if (ret) |
| goto out_err; |
| |
| /* increment the number of watches the user has */ |
| if (!inc_inotify_watches(group->inotify_data.ucounts)) { |
| inotify_remove_from_idr(group, tmp_i_mark); |
| ret = -ENOSPC; |
| goto out_err; |
| } |
| |
| /* we are on the idr, now get on the inode */ |
| ret = fsnotify_add_inode_mark_locked(&tmp_i_mark->fsn_mark, inode, 0); |
| if (ret) { |
| /* we failed to get on the inode, get off the idr */ |
| inotify_remove_from_idr(group, tmp_i_mark); |
| goto out_err; |
| } |
| |
| |
| /* return the watch descriptor for this new mark */ |
| ret = tmp_i_mark->wd; |
| |
| out_err: |
| /* match the ref from fsnotify_init_mark() */ |
| fsnotify_put_mark(&tmp_i_mark->fsn_mark); |
| |
| return ret; |
| } |
| |
| static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) |
| { |
| int ret = 0; |
| |
| mutex_lock(&group->mark_mutex); |
| /* try to update and existing watch with the new arg */ |
| ret = inotify_update_existing_watch(group, inode, arg); |
| /* no mark present, try to add a new one */ |
| if (ret == -ENOENT) |
| ret = inotify_new_watch(group, inode, arg); |
| mutex_unlock(&group->mark_mutex); |
| |
| return ret; |
| } |
| |
| static struct fsnotify_group *inotify_new_group(unsigned int max_events) |
| { |
| struct fsnotify_group *group; |
| struct inotify_event_info *oevent; |
| |
| group = fsnotify_alloc_group(&inotify_fsnotify_ops); |
| if (IS_ERR(group)) |
| return group; |
| |
| oevent = kmalloc(sizeof(struct inotify_event_info), GFP_KERNEL); |
| if (unlikely(!oevent)) { |
| fsnotify_destroy_group(group); |
| return ERR_PTR(-ENOMEM); |
| } |
| group->overflow_event = &oevent->fse; |
| fsnotify_init_event(group->overflow_event, NULL, FS_Q_OVERFLOW); |
| oevent->wd = -1; |
| oevent->sync_cookie = 0; |
| oevent->name_len = 0; |
| |
| group->max_events = max_events; |
| |
| spin_lock_init(&group->inotify_data.idr_lock); |
| idr_init(&group->inotify_data.idr); |
| group->inotify_data.ucounts = inc_ucount(current_user_ns(), |
| current_euid(), |
| UCOUNT_INOTIFY_INSTANCES); |
| |
| if (!group->inotify_data.ucounts) { |
| fsnotify_destroy_group(group); |
| return ERR_PTR(-EMFILE); |
| } |
| |
| return group; |
| } |
| |
| |
| /* inotify syscalls */ |
| static int do_inotify_init(int flags) |
| { |
| struct fsnotify_group *group; |
| int ret; |
| |
| /* Check the IN_* constants for consistency. */ |
| BUILD_BUG_ON(IN_CLOEXEC != O_CLOEXEC); |
| BUILD_BUG_ON(IN_NONBLOCK != O_NONBLOCK); |
| |
| if (flags & ~(IN_CLOEXEC | IN_NONBLOCK)) |
| return -EINVAL; |
| |
| /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ |
| group = inotify_new_group(inotify_max_queued_events); |
| if (IS_ERR(group)) |
| return PTR_ERR(group); |
| |
| ret = anon_inode_getfd("inotify", &inotify_fops, group, |
| O_RDONLY | flags); |
| if (ret < 0) |
| fsnotify_destroy_group(group); |
| |
| return ret; |
| } |
| |
| SYSCALL_DEFINE1(inotify_init1, int, flags) |
| { |
| return do_inotify_init(flags); |
| } |
| |
| SYSCALL_DEFINE0(inotify_init) |
| { |
| return do_inotify_init(0); |
| } |
| |
| SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname, |
| u32, mask) |
| { |
| struct fsnotify_group *group; |
| struct inode *inode; |
| struct path path; |
| struct fd f; |
| int ret; |
| unsigned flags = 0; |
| |
| /* |
| * We share a lot of code with fs/dnotify. We also share |
| * the bit layout between inotify's IN_* and the fsnotify |
| * FS_*. This check ensures that only the inotify IN_* |
| * bits get passed in and set in watches/events. |
| */ |
| if (unlikely(mask & ~ALL_INOTIFY_BITS)) |
| return -EINVAL; |
| /* |
| * Require at least one valid bit set in the mask. |
| * Without _something_ set, we would have no events to |
| * watch for. |
| */ |
| if (unlikely(!(mask & ALL_INOTIFY_BITS))) |
| return -EINVAL; |
| |
| f = fdget(fd); |
| if (unlikely(!f.file)) |
| return -EBADF; |
| |
| /* verify that this is indeed an inotify instance */ |
| if (unlikely(f.file->f_op != &inotify_fops)) { |
| ret = -EINVAL; |
| goto fput_and_out; |
| } |
| |
| if (!(mask & IN_DONT_FOLLOW)) |
| flags |= LOOKUP_FOLLOW; |
| if (mask & IN_ONLYDIR) |
| flags |= LOOKUP_DIRECTORY; |
| |
| ret = inotify_find_inode(pathname, &path, flags); |
| if (ret) |
| goto fput_and_out; |
| |
| /* inode held in place by reference to path; group by fget on fd */ |
| inode = path.dentry->d_inode; |
| group = f.file->private_data; |
| |
| /* create/update an inode mark */ |
| ret = inotify_update_watch(group, inode, mask); |
| path_put(&path); |
| fput_and_out: |
| fdput(f); |
| return ret; |
| } |
| |
| SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) |
| { |
| struct fsnotify_group *group; |
| struct inotify_inode_mark *i_mark; |
| struct fd f; |
| int ret = 0; |
| |
| f = fdget(fd); |
| if (unlikely(!f.file)) |
| return -EBADF; |
| |
| /* verify that this is indeed an inotify instance */ |
| ret = -EINVAL; |
| if (unlikely(f.file->f_op != &inotify_fops)) |
| goto out; |
| |
| group = f.file->private_data; |
| |
| ret = -EINVAL; |
| i_mark = inotify_idr_find(group, wd); |
| if (unlikely(!i_mark)) |
| goto out; |
| |
| ret = 0; |
| |
| fsnotify_destroy_mark(&i_mark->fsn_mark, group); |
| |
| /* match ref taken by inotify_idr_find */ |
| fsnotify_put_mark(&i_mark->fsn_mark); |
| |
| out: |
| fdput(f); |
| return ret; |
| } |
| |
| /* |
| * inotify_user_setup - Our initialization function. Note that we cannot return |
| * error because we have compiled-in VFS hooks. So an (unlikely) failure here |
| * must result in panic(). |
| */ |
| static int __init inotify_user_setup(void) |
| { |
| BUILD_BUG_ON(IN_ACCESS != FS_ACCESS); |
| BUILD_BUG_ON(IN_MODIFY != FS_MODIFY); |
| BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB); |
| BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE); |
| BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); |
| BUILD_BUG_ON(IN_OPEN != FS_OPEN); |
| BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM); |
| BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO); |
| BUILD_BUG_ON(IN_CREATE != FS_CREATE); |
| BUILD_BUG_ON(IN_DELETE != FS_DELETE); |
| BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF); |
| BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF); |
| BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT); |
| BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW); |
| BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED); |
| BUILD_BUG_ON(IN_EXCL_UNLINK != FS_EXCL_UNLINK); |
| BUILD_BUG_ON(IN_ISDIR != FS_ISDIR); |
| BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT); |
| |
| BUG_ON(hweight32(ALL_INOTIFY_BITS) != 21); |
| |
| inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC); |
| |
| inotify_max_queued_events = 16384; |
| init_user_ns.ucount_max[UCOUNT_INOTIFY_INSTANCES] = 128; |
| init_user_ns.ucount_max[UCOUNT_INOTIFY_WATCHES] = 8192; |
| |
| return 0; |
| } |
| fs_initcall(inotify_user_setup); |