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![Lino Sanfilippo](/assets/img/avatar_default.png)
In inotify_new_watch() the number of watches for a group is compared against the max number of allowed watches and increased afterwards. The check and incrementation is not done atomically, so it is possible for multiple concurrent threads to pass the check and increment the number of marks above the allowed max. This patch uses an inotify groups mark_lock to ensure that both check and incrementation are done atomic. Furthermore we dont have to worry about the race that allows a concurrent thread to add a watch just after inotify_update_existing_watch() returned with -ENOENT anymore, since this is also synchronized by the groups mark mutex now. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
847 lines
21 KiB
C
847 lines
21 KiB
C
/*
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* fs/inotify_user.c - inotify support for userspace
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*
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* Authors:
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* John McCutchan <ttb@tentacle.dhs.org>
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* Robert Love <rml@novell.com>
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*
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* Copyright (C) 2005 John McCutchan
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* Copyright 2006 Hewlett-Packard Development Company, L.P.
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*
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* Copyright (C) 2009 Eric Paris <Red Hat Inc>
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* inotify was largely rewriten to make use of the fsnotify infrastructure
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/file.h>
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#include <linux/fs.h> /* struct inode */
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#include <linux/fsnotify_backend.h>
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#include <linux/idr.h>
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#include <linux/init.h> /* module_init */
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#include <linux/inotify.h>
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#include <linux/kernel.h> /* roundup() */
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#include <linux/namei.h> /* LOOKUP_FOLLOW */
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#include <linux/sched.h> /* struct user */
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#include <linux/slab.h> /* struct kmem_cache */
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#include <linux/syscalls.h>
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#include <linux/types.h>
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#include <linux/anon_inodes.h>
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#include <linux/uaccess.h>
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#include <linux/poll.h>
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#include <linux/wait.h>
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#include "inotify.h"
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#include "../fdinfo.h"
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#include <asm/ioctls.h>
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/* these are configurable via /proc/sys/fs/inotify/ */
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static int inotify_max_user_instances __read_mostly;
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static int inotify_max_queued_events __read_mostly;
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static int inotify_max_user_watches __read_mostly;
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static struct kmem_cache *inotify_inode_mark_cachep __read_mostly;
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struct kmem_cache *event_priv_cachep __read_mostly;
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#ifdef CONFIG_SYSCTL
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#include <linux/sysctl.h>
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static int zero;
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ctl_table inotify_table[] = {
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{
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.procname = "max_user_instances",
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.data = &inotify_max_user_instances,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &zero,
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},
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{
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.procname = "max_user_watches",
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.data = &inotify_max_user_watches,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &zero,
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},
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{
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.procname = "max_queued_events",
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.data = &inotify_max_queued_events,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &zero
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},
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{ }
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};
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#endif /* CONFIG_SYSCTL */
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static inline __u32 inotify_arg_to_mask(u32 arg)
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{
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__u32 mask;
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/*
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* everything should accept their own ignored, cares about children,
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* and should receive events when the inode is unmounted
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*/
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mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD | FS_UNMOUNT);
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/* mask off the flags used to open the fd */
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mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT | IN_EXCL_UNLINK));
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return mask;
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}
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static inline u32 inotify_mask_to_arg(__u32 mask)
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{
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return mask & (IN_ALL_EVENTS | IN_ISDIR | IN_UNMOUNT | IN_IGNORED |
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IN_Q_OVERFLOW);
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}
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/* intofiy userspace file descriptor functions */
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static unsigned int inotify_poll(struct file *file, poll_table *wait)
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{
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struct fsnotify_group *group = file->private_data;
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int ret = 0;
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poll_wait(file, &group->notification_waitq, wait);
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mutex_lock(&group->notification_mutex);
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if (!fsnotify_notify_queue_is_empty(group))
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ret = POLLIN | POLLRDNORM;
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mutex_unlock(&group->notification_mutex);
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return ret;
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}
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/*
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* Get an inotify_kernel_event if one exists and is small
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* enough to fit in "count". Return an error pointer if
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* not large enough.
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*
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* Called with the group->notification_mutex held.
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*/
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static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
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size_t count)
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{
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size_t event_size = sizeof(struct inotify_event);
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struct fsnotify_event *event;
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if (fsnotify_notify_queue_is_empty(group))
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return NULL;
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event = fsnotify_peek_notify_event(group);
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pr_debug("%s: group=%p event=%p\n", __func__, group, event);
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if (event->name_len)
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event_size += roundup(event->name_len + 1, event_size);
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if (event_size > count)
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return ERR_PTR(-EINVAL);
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/* held the notification_mutex the whole time, so this is the
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* same event we peeked above */
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fsnotify_remove_notify_event(group);
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return event;
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}
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/*
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* Copy an event to user space, returning how much we copied.
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*
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* We already checked that the event size is smaller than the
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* buffer we had in "get_one_event()" above.
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*/
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static ssize_t copy_event_to_user(struct fsnotify_group *group,
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struct fsnotify_event *event,
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char __user *buf)
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{
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struct inotify_event inotify_event;
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struct fsnotify_event_private_data *fsn_priv;
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struct inotify_event_private_data *priv;
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size_t event_size = sizeof(struct inotify_event);
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size_t name_len = 0;
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pr_debug("%s: group=%p event=%p\n", __func__, group, event);
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/* we get the inotify watch descriptor from the event private data */
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spin_lock(&event->lock);
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fsn_priv = fsnotify_remove_priv_from_event(group, event);
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spin_unlock(&event->lock);
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if (!fsn_priv)
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inotify_event.wd = -1;
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else {
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priv = container_of(fsn_priv, struct inotify_event_private_data,
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fsnotify_event_priv_data);
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inotify_event.wd = priv->wd;
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inotify_free_event_priv(fsn_priv);
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}
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/*
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* round up event->name_len so it is a multiple of event_size
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* plus an extra byte for the terminating '\0'.
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*/
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if (event->name_len)
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name_len = roundup(event->name_len + 1, event_size);
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inotify_event.len = name_len;
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inotify_event.mask = inotify_mask_to_arg(event->mask);
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inotify_event.cookie = event->sync_cookie;
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/* send the main event */
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if (copy_to_user(buf, &inotify_event, event_size))
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return -EFAULT;
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buf += event_size;
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/*
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* fsnotify only stores the pathname, so here we have to send the pathname
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* and then pad that pathname out to a multiple of sizeof(inotify_event)
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* with zeros. I get my zeros from the nul_inotify_event.
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*/
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if (name_len) {
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unsigned int len_to_zero = name_len - event->name_len;
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/* copy the path name */
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if (copy_to_user(buf, event->file_name, event->name_len))
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return -EFAULT;
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buf += event->name_len;
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/* fill userspace with 0's */
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if (clear_user(buf, len_to_zero))
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return -EFAULT;
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buf += len_to_zero;
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event_size += name_len;
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}
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return event_size;
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}
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static ssize_t inotify_read(struct file *file, char __user *buf,
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size_t count, loff_t *pos)
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{
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struct fsnotify_group *group;
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struct fsnotify_event *kevent;
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char __user *start;
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int ret;
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DEFINE_WAIT(wait);
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start = buf;
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group = file->private_data;
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while (1) {
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prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE);
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mutex_lock(&group->notification_mutex);
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kevent = get_one_event(group, count);
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mutex_unlock(&group->notification_mutex);
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pr_debug("%s: group=%p kevent=%p\n", __func__, group, kevent);
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if (kevent) {
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ret = PTR_ERR(kevent);
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if (IS_ERR(kevent))
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break;
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ret = copy_event_to_user(group, kevent, buf);
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fsnotify_put_event(kevent);
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if (ret < 0)
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break;
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buf += ret;
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count -= ret;
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continue;
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}
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ret = -EAGAIN;
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if (file->f_flags & O_NONBLOCK)
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break;
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ret = -ERESTARTSYS;
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if (signal_pending(current))
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break;
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if (start != buf)
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break;
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schedule();
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}
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finish_wait(&group->notification_waitq, &wait);
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if (start != buf && ret != -EFAULT)
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ret = buf - start;
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return ret;
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}
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static int inotify_release(struct inode *ignored, struct file *file)
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{
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struct fsnotify_group *group = file->private_data;
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pr_debug("%s: group=%p\n", __func__, group);
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/* free this group, matching get was inotify_init->fsnotify_obtain_group */
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fsnotify_destroy_group(group);
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return 0;
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}
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static long inotify_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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struct fsnotify_group *group;
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struct fsnotify_event_holder *holder;
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struct fsnotify_event *event;
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void __user *p;
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int ret = -ENOTTY;
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size_t send_len = 0;
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group = file->private_data;
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p = (void __user *) arg;
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pr_debug("%s: group=%p cmd=%u\n", __func__, group, cmd);
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switch (cmd) {
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case FIONREAD:
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mutex_lock(&group->notification_mutex);
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list_for_each_entry(holder, &group->notification_list, event_list) {
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event = holder->event;
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send_len += sizeof(struct inotify_event);
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if (event->name_len)
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send_len += roundup(event->name_len + 1,
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sizeof(struct inotify_event));
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}
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mutex_unlock(&group->notification_mutex);
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ret = put_user(send_len, (int __user *) p);
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break;
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}
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return ret;
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}
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static const struct file_operations inotify_fops = {
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.show_fdinfo = inotify_show_fdinfo,
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.poll = inotify_poll,
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.read = inotify_read,
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.fasync = fsnotify_fasync,
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.release = inotify_release,
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.unlocked_ioctl = inotify_ioctl,
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.compat_ioctl = inotify_ioctl,
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.llseek = noop_llseek,
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};
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/*
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* find_inode - resolve a user-given path to a specific inode
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*/
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static int inotify_find_inode(const char __user *dirname, struct path *path, unsigned flags)
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{
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int error;
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error = user_path_at(AT_FDCWD, dirname, flags, path);
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if (error)
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return error;
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/* you can only watch an inode if you have read permissions on it */
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error = inode_permission(path->dentry->d_inode, MAY_READ);
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if (error)
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path_put(path);
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return error;
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}
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static int inotify_add_to_idr(struct idr *idr, spinlock_t *idr_lock,
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struct inotify_inode_mark *i_mark)
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{
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int ret;
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idr_preload(GFP_KERNEL);
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spin_lock(idr_lock);
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ret = idr_alloc_cyclic(idr, i_mark, 1, 0, GFP_NOWAIT);
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if (ret >= 0) {
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/* we added the mark to the idr, take a reference */
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i_mark->wd = ret;
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fsnotify_get_mark(&i_mark->fsn_mark);
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}
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spin_unlock(idr_lock);
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idr_preload_end();
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return ret < 0 ? ret : 0;
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}
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static struct inotify_inode_mark *inotify_idr_find_locked(struct fsnotify_group *group,
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int wd)
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{
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struct idr *idr = &group->inotify_data.idr;
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spinlock_t *idr_lock = &group->inotify_data.idr_lock;
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struct inotify_inode_mark *i_mark;
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assert_spin_locked(idr_lock);
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i_mark = idr_find(idr, wd);
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if (i_mark) {
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struct fsnotify_mark *fsn_mark = &i_mark->fsn_mark;
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fsnotify_get_mark(fsn_mark);
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/* One ref for being in the idr, one ref we just took */
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BUG_ON(atomic_read(&fsn_mark->refcnt) < 2);
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}
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return i_mark;
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}
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static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group,
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int wd)
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{
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struct inotify_inode_mark *i_mark;
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spinlock_t *idr_lock = &group->inotify_data.idr_lock;
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spin_lock(idr_lock);
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i_mark = inotify_idr_find_locked(group, wd);
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spin_unlock(idr_lock);
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return i_mark;
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}
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static void do_inotify_remove_from_idr(struct fsnotify_group *group,
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struct inotify_inode_mark *i_mark)
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{
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struct idr *idr = &group->inotify_data.idr;
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spinlock_t *idr_lock = &group->inotify_data.idr_lock;
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int wd = i_mark->wd;
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assert_spin_locked(idr_lock);
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idr_remove(idr, wd);
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/* removed from the idr, drop that ref */
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fsnotify_put_mark(&i_mark->fsn_mark);
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}
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/*
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* Remove the mark from the idr (if present) and drop the reference
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* on the mark because it was in the idr.
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*/
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static void inotify_remove_from_idr(struct fsnotify_group *group,
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struct inotify_inode_mark *i_mark)
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{
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spinlock_t *idr_lock = &group->inotify_data.idr_lock;
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struct inotify_inode_mark *found_i_mark = NULL;
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int wd;
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spin_lock(idr_lock);
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wd = i_mark->wd;
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/*
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* does this i_mark think it is in the idr? we shouldn't get called
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* if it wasn't....
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*/
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if (wd == -1) {
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WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p"
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" i_mark->inode=%p\n", __func__, i_mark, i_mark->wd,
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i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode);
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goto out;
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}
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/* Lets look in the idr to see if we find it */
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found_i_mark = inotify_idr_find_locked(group, wd);
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if (unlikely(!found_i_mark)) {
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WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p"
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" i_mark->inode=%p\n", __func__, i_mark, i_mark->wd,
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i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode);
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goto out;
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}
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/*
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* We found an mark in the idr at the right wd, but it's
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* not the mark we were told to remove. eparis seriously
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* fucked up somewhere.
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*/
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if (unlikely(found_i_mark != i_mark)) {
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WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p "
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"mark->inode=%p found_i_mark=%p found_i_mark->wd=%d "
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"found_i_mark->group=%p found_i_mark->inode=%p\n",
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__func__, i_mark, i_mark->wd, i_mark->fsn_mark.group,
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i_mark->fsn_mark.i.inode, found_i_mark, found_i_mark->wd,
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found_i_mark->fsn_mark.group,
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found_i_mark->fsn_mark.i.inode);
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goto out;
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}
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/*
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* One ref for being in the idr
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* one ref held by the caller trying to kill us
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* one ref grabbed by inotify_idr_find
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*/
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if (unlikely(atomic_read(&i_mark->fsn_mark.refcnt) < 3)) {
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printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p"
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" i_mark->inode=%p\n", __func__, i_mark, i_mark->wd,
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i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode);
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|
/* we can't really recover with bad ref cnting.. */
|
|
BUG();
|
|
}
|
|
|
|
do_inotify_remove_from_idr(group, i_mark);
|
|
out:
|
|
/* match the ref taken by inotify_idr_find_locked() */
|
|
if (found_i_mark)
|
|
fsnotify_put_mark(&found_i_mark->fsn_mark);
|
|
i_mark->wd = -1;
|
|
spin_unlock(idr_lock);
|
|
}
|
|
|
|
/*
|
|
* 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_event *ignored_event, *notify_event;
|
|
struct inotify_event_private_data *event_priv;
|
|
struct fsnotify_event_private_data *fsn_event_priv;
|
|
int ret;
|
|
|
|
i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
|
|
|
|
ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL,
|
|
FSNOTIFY_EVENT_NONE, NULL, 0,
|
|
GFP_NOFS);
|
|
if (!ignored_event)
|
|
goto skip_send_ignore;
|
|
|
|
event_priv = kmem_cache_alloc(event_priv_cachep, GFP_NOFS);
|
|
if (unlikely(!event_priv))
|
|
goto skip_send_ignore;
|
|
|
|
fsn_event_priv = &event_priv->fsnotify_event_priv_data;
|
|
|
|
fsnotify_get_group(group);
|
|
fsn_event_priv->group = group;
|
|
event_priv->wd = i_mark->wd;
|
|
|
|
notify_event = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv, NULL);
|
|
if (notify_event) {
|
|
if (IS_ERR(notify_event))
|
|
ret = PTR_ERR(notify_event);
|
|
else
|
|
fsnotify_put_event(notify_event);
|
|
inotify_free_event_priv(fsn_event_priv);
|
|
}
|
|
|
|
skip_send_ignore:
|
|
/* matches the reference taken when the event was created */
|
|
if (ignored_event)
|
|
fsnotify_put_event(ignored_event);
|
|
|
|
/* remove this mark from the idr */
|
|
inotify_remove_from_idr(group, i_mark);
|
|
|
|
atomic_dec(&group->inotify_data.user->inotify_watches);
|
|
}
|
|
|
|
/* ding dong the mark is dead */
|
|
static void inotify_free_mark(struct fsnotify_mark *fsn_mark)
|
|
{
|
|
struct inotify_inode_mark *i_mark;
|
|
|
|
i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
|
|
|
|
kmem_cache_free(inotify_inode_mark_cachep, i_mark);
|
|
}
|
|
|
|
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_inode_mark(group, inode);
|
|
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)
|
|
fsnotify_set_mark_mask_locked(fsn_mark, (fsn_mark->mask | mask));
|
|
else
|
|
fsnotify_set_mark_mask_locked(fsn_mark, 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_inode_mask(inode);
|
|
|
|
}
|
|
|
|
/* 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, inotify_free_mark);
|
|
tmp_i_mark->fsn_mark.mask = mask;
|
|
tmp_i_mark->wd = -1;
|
|
|
|
ret = -ENOSPC;
|
|
if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches)
|
|
goto out_err;
|
|
|
|
ret = inotify_add_to_idr(idr, idr_lock, tmp_i_mark);
|
|
if (ret)
|
|
goto out_err;
|
|
|
|
/* we are on the idr, now get on the inode */
|
|
ret = fsnotify_add_mark_locked(&tmp_i_mark->fsn_mark, group, inode,
|
|
NULL, 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;
|
|
}
|
|
|
|
/* increment the number of watches the user has */
|
|
atomic_inc(&group->inotify_data.user->inotify_watches);
|
|
|
|
/* 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;
|
|
|
|
group = fsnotify_alloc_group(&inotify_fsnotify_ops);
|
|
if (IS_ERR(group))
|
|
return group;
|
|
|
|
group->max_events = max_events;
|
|
|
|
spin_lock_init(&group->inotify_data.idr_lock);
|
|
idr_init(&group->inotify_data.idr);
|
|
group->inotify_data.user = get_current_user();
|
|
|
|
if (atomic_inc_return(&group->inotify_data.user->inotify_devs) >
|
|
inotify_max_user_instances) {
|
|
fsnotify_destroy_group(group);
|
|
return ERR_PTR(-EMFILE);
|
|
}
|
|
|
|
return group;
|
|
}
|
|
|
|
|
|
/* inotify syscalls */
|
|
SYSCALL_DEFINE1(inotify_init1, 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_DEFINE0(inotify_init)
|
|
{
|
|
return sys_inotify_init1(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;
|
|
|
|
/* don't allow invalid bits: we don't want flags set */
|
|
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);
|
|
event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC);
|
|
|
|
inotify_max_queued_events = 16384;
|
|
inotify_max_user_instances = 128;
|
|
inotify_max_user_watches = 8192;
|
|
|
|
return 0;
|
|
}
|
|
module_init(inotify_user_setup);
|