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850 lines
21 KiB
850 lines
21 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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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 <[email protected]> |
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* Robert Love <[email protected]> |
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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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|
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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> /* fs_initcall */ |
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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/signal.h> |
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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 <linux/memcontrol.h> |
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#include <linux/security.h> |
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|
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#include "inotify.h" |
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#include "../fdinfo.h" |
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|
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#include <asm/ioctls.h> |
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|
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/* |
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* An inotify watch requires allocating an inotify_inode_mark structure as |
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* well as pinning the watched inode. Doubling the size of a VFS inode |
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* should be more than enough to cover the additional filesystem inode |
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* size increase. |
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*/ |
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#define INOTIFY_WATCH_COST (sizeof(struct inotify_inode_mark) + \ |
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2 * sizeof(struct inode)) |
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|
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/* configurable via /proc/sys/fs/inotify/ */ |
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static int inotify_max_queued_events __read_mostly; |
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|
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struct kmem_cache *inotify_inode_mark_cachep __read_mostly; |
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|
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#ifdef CONFIG_SYSCTL |
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#include <linux/sysctl.h> |
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struct ctl_table inotify_table[] = { |
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{ |
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.procname = "max_user_instances", |
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.data = &init_user_ns.ucount_max[UCOUNT_INOTIFY_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 = SYSCTL_ZERO, |
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}, |
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{ |
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.procname = "max_user_watches", |
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.data = &init_user_ns.ucount_max[UCOUNT_INOTIFY_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 = SYSCTL_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 = SYSCTL_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(struct inode *inode, u32 arg) |
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{ |
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__u32 mask; |
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|
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/* |
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* Everything should accept their own ignored and should receive events |
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* when the inode is unmounted. All directories care about children. |
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*/ |
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mask = (FS_IN_IGNORED | FS_UNMOUNT); |
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if (S_ISDIR(inode->i_mode)) |
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mask |= FS_EVENT_ON_CHILD; |
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|
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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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|
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/* intofiy userspace file descriptor functions */ |
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static __poll_t 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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__poll_t ret = 0; |
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poll_wait(file, &group->notification_waitq, wait); |
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spin_lock(&group->notification_lock); |
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if (!fsnotify_notify_queue_is_empty(group)) |
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ret = EPOLLIN | EPOLLRDNORM; |
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spin_unlock(&group->notification_lock); |
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return ret; |
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} |
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static int round_event_name_len(struct fsnotify_event *fsn_event) |
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{ |
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struct inotify_event_info *event; |
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event = INOTIFY_E(fsn_event); |
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if (!event->name_len) |
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return 0; |
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return roundup(event->name_len + 1, sizeof(struct inotify_event)); |
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} |
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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_lock 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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event = fsnotify_peek_first_event(group); |
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if (!event) |
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return NULL; |
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pr_debug("%s: group=%p event=%p\n", __func__, group, event); |
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event_size += round_event_name_len(event); |
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if (event_size > count) |
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return ERR_PTR(-EINVAL); |
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/* held the notification_lock the whole time, so this is the |
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* same event we peeked above */ |
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fsnotify_remove_first_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 *fsn_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 inotify_event_info *event; |
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size_t event_size = sizeof(struct inotify_event); |
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size_t name_len; |
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size_t pad_name_len; |
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pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event); |
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event = INOTIFY_E(fsn_event); |
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name_len = event->name_len; |
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/* |
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* round up name length 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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pad_name_len = round_event_name_len(fsn_event); |
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inotify_event.len = pad_name_len; |
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inotify_event.mask = inotify_mask_to_arg(event->mask); |
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inotify_event.wd = event->wd; |
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inotify_event.cookie = event->sync_cookie; |
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|
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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. |
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*/ |
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if (pad_name_len) { |
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/* copy the path name */ |
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if (copy_to_user(buf, event->name, name_len)) |
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return -EFAULT; |
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buf += name_len; |
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/* fill userspace with 0's */ |
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if (clear_user(buf, pad_name_len - name_len)) |
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return -EFAULT; |
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event_size += pad_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_FUNC(wait, woken_wake_function); |
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start = buf; |
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group = file->private_data; |
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add_wait_queue(&group->notification_waitq, &wait); |
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while (1) { |
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spin_lock(&group->notification_lock); |
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kevent = get_one_event(group, count); |
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spin_unlock(&group->notification_lock); |
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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_destroy_event(group, 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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wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
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} |
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remove_wait_queue(&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 *fsn_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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spin_lock(&group->notification_lock); |
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list_for_each_entry(fsn_event, &group->notification_list, |
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list) { |
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send_len += sizeof(struct inotify_event); |
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send_len += round_event_name_len(fsn_event); |
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} |
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spin_unlock(&group->notification_lock); |
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ret = put_user(send_len, (int __user *) p); |
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break; |
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#ifdef CONFIG_CHECKPOINT_RESTORE |
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case INOTIFY_IOC_SETNEXTWD: |
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ret = -EINVAL; |
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if (arg >= 1 && arg <= INT_MAX) { |
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struct inotify_group_private_data *data; |
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data = &group->inotify_data; |
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spin_lock(&data->idr_lock); |
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idr_set_cursor(&data->idr, (unsigned int)arg); |
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spin_unlock(&data->idr_lock); |
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ret = 0; |
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} |
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break; |
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#endif /* CONFIG_CHECKPOINT_RESTORE */ |
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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, |
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unsigned int flags, __u64 mask) |
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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 = path_permission(path, 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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error = security_path_notify(path, mask, |
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FSNOTIFY_OBJ_TYPE_INODE); |
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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(refcount_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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/* |
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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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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 *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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/* |
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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\n", |
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__func__, i_mark, i_mark->wd, i_mark->fsn_mark.group); |
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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\n", |
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__func__, i_mark, i_mark->wd, i_mark->fsn_mark.group); |
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goto out; |
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} |
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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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"found_i_mark=%p found_i_mark->wd=%d " |
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"found_i_mark->group=%p\n", __func__, i_mark, |
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i_mark->wd, i_mark->fsn_mark.group, found_i_mark, |
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found_i_mark->wd, found_i_mark->fsn_mark.group); |
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goto out; |
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} |
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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 grabbed by inotify_idr_find |
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*/ |
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if (unlikely(refcount_read(&i_mark->fsn_mark.refcnt) < 2)) { |
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printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p\n", |
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__func__, i_mark, i_mark->wd, i_mark->fsn_mark.group); |
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/* we can't really recover with bad ref cnting.. */ |
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BUG(); |
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} |
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|
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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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out: |
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i_mark->wd = -1; |
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spin_unlock(idr_lock); |
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/* match the ref taken by inotify_idr_find_locked() */ |
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if (found_i_mark) |
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fsnotify_put_mark(&found_i_mark->fsn_mark); |
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} |
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|
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/* |
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* Send IN_IGNORED for this wd, remove this wd from the idr. |
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*/ |
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void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, |
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struct fsnotify_group *group) |
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{ |
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struct inotify_inode_mark *i_mark; |
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|
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/* Queue ignore event for the watch */ |
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inotify_handle_inode_event(fsn_mark, FS_IN_IGNORED, NULL, NULL, NULL, |
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0); |
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|
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i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); |
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/* remove this mark from the idr */ |
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inotify_remove_from_idr(group, i_mark); |
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|
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dec_inotify_watches(group->inotify_data.ucounts); |
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} |
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|
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static int inotify_update_existing_watch(struct fsnotify_group *group, |
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struct inode *inode, |
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u32 arg) |
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{ |
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struct fsnotify_mark *fsn_mark; |
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struct inotify_inode_mark *i_mark; |
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__u32 old_mask, new_mask; |
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__u32 mask; |
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int add = (arg & IN_MASK_ADD); |
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int create = (arg & IN_MASK_CREATE); |
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int ret; |
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|
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mask = inotify_arg_to_mask(inode, arg); |
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|
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fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group); |
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if (!fsn_mark) |
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return -ENOENT; |
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else if (create) { |
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ret = -EEXIST; |
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goto out; |
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} |
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|
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i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); |
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|
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spin_lock(&fsn_mark->lock); |
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old_mask = fsn_mark->mask; |
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if (add) |
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fsn_mark->mask |= mask; |
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else |
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fsn_mark->mask = mask; |
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new_mask = fsn_mark->mask; |
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spin_unlock(&fsn_mark->lock); |
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|
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if (old_mask != new_mask) { |
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/* more bits in old than in new? */ |
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int dropped = (old_mask & ~new_mask); |
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/* more bits in this fsn_mark than the inode's mask? */ |
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int do_inode = (new_mask & ~inode->i_fsnotify_mask); |
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|
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/* update the inode with this new fsn_mark */ |
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if (dropped || do_inode) |
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fsnotify_recalc_mask(inode->i_fsnotify_marks); |
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|
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} |
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|
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/* return the wd */ |
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ret = i_mark->wd; |
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|
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out: |
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/* match the get from fsnotify_find_mark() */ |
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fsnotify_put_mark(fsn_mark); |
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|
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return ret; |
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} |
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|
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static int inotify_new_watch(struct fsnotify_group *group, |
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struct inode *inode, |
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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(inode, 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_user_group(&inotify_fsnotify_ops); |
|
if (IS_ERR(group)) |
|
return group; |
|
|
|
oevent = kmalloc(sizeof(struct inotify_event_info), GFP_KERNEL_ACCOUNT); |
|
if (unlikely(!oevent)) { |
|
fsnotify_destroy_group(group); |
|
return ERR_PTR(-ENOMEM); |
|
} |
|
group->overflow_event = &oevent->fse; |
|
fsnotify_init_event(group->overflow_event); |
|
oevent->mask = FS_Q_OVERFLOW; |
|
oevent->wd = -1; |
|
oevent->sync_cookie = 0; |
|
oevent->name_len = 0; |
|
|
|
group->max_events = max_events; |
|
group->memcg = get_mem_cgroup_from_mm(current->mm); |
|
|
|
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; |
|
|
|
/* IN_MASK_ADD and IN_MASK_CREATE don't make sense together */ |
|
if (unlikely((mask & IN_MASK_ADD) && (mask & IN_MASK_CREATE))) { |
|
ret = -EINVAL; |
|
goto fput_and_out; |
|
} |
|
|
|
/* 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, |
|
(mask & IN_ALL_EVENTS)); |
|
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 = -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)) |
|
goto out; |
|
|
|
group = f.file->private_data; |
|
|
|
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) |
|
{ |
|
unsigned long watches_max; |
|
struct sysinfo si; |
|
|
|
si_meminfo(&si); |
|
/* |
|
* Allow up to 1% of addressable memory to be allocated for inotify |
|
* watches (per user) limited to the range [8192, 1048576]. |
|
*/ |
|
watches_max = (((si.totalram - si.totalhigh) / 100) << PAGE_SHIFT) / |
|
INOTIFY_WATCH_COST; |
|
watches_max = clamp(watches_max, 8192UL, 1048576UL); |
|
|
|
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); |
|
|
|
BUILD_BUG_ON(HWEIGHT32(ALL_INOTIFY_BITS) != 22); |
|
|
|
inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, |
|
SLAB_PANIC|SLAB_ACCOUNT); |
|
|
|
inotify_max_queued_events = 16384; |
|
init_user_ns.ucount_max[UCOUNT_INOTIFY_INSTANCES] = 128; |
|
init_user_ns.ucount_max[UCOUNT_INOTIFY_WATCHES] = watches_max; |
|
|
|
return 0; |
|
} |
|
fs_initcall(inotify_user_setup);
|
|
|