| /* |
| * fs/inotify_user.c - inotify support for userspace |
| * |
| * Authors: |
| * John McCutchan <ttb@tentacle.dhs.org> |
| * Robert Love <rml@novell.com> |
| * |
| * Copyright (C) 2005 John McCutchan |
| * Copyright 2006 Hewlett-Packard Development Company, L.P. |
| * |
| * Copyright (C) 2009 Eric Paris <Red Hat Inc> |
| * inotify was largely rewriten to make use of the fsnotify infrastructure |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the |
| * Free Software Foundation; either version 2, or (at your option) any |
| * later version. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| */ |
| |
| #include <linux/fs.h> /* struct inode */ |
| #include <linux/fsnotify_backend.h> |
| #include <linux/inotify.h> |
| #include <linux/path.h> /* struct path */ |
| #include <linux/slab.h> /* kmem_* */ |
| #include <linux/types.h> |
| #include <linux/sched.h> |
| |
| #include "inotify.h" |
| |
| /* |
| * Check if 2 events contain the same information. We do not compare private data |
| * but at this moment that isn't a problem for any know fsnotify listeners. |
| */ |
| static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new) |
| { |
| if ((old->mask == new->mask) && |
| (old->to_tell == new->to_tell) && |
| (old->data_type == new->data_type) && |
| (old->name_len == new->name_len)) { |
| switch (old->data_type) { |
| case (FSNOTIFY_EVENT_INODE): |
| /* remember, after old was put on the wait_q we aren't |
| * allowed to look at the inode any more, only thing |
| * left to check was if the file_name is the same */ |
| if (!old->name_len || |
| !strcmp(old->file_name, new->file_name)) |
| return true; |
| break; |
| case (FSNOTIFY_EVENT_PATH): |
| if ((old->path.mnt == new->path.mnt) && |
| (old->path.dentry == new->path.dentry)) |
| return true; |
| break; |
| case (FSNOTIFY_EVENT_NONE): |
| if (old->mask & FS_Q_OVERFLOW) |
| return true; |
| else if (old->mask & FS_IN_IGNORED) |
| return false; |
| return true; |
| }; |
| } |
| return false; |
| } |
| |
| static int inotify_merge(struct list_head *list, struct fsnotify_event *event) |
| { |
| struct fsnotify_event_holder *last_holder; |
| struct fsnotify_event *last_event; |
| int ret = 0; |
| |
| /* and the list better be locked by something too */ |
| spin_lock(&event->lock); |
| |
| last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list); |
| last_event = last_holder->event; |
| if (event_compare(last_event, event)) |
| ret = -EEXIST; |
| |
| spin_unlock(&event->lock); |
| |
| return ret; |
| } |
| |
| static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) |
| { |
| struct fsnotify_mark_entry *entry; |
| struct inotify_inode_mark_entry *ientry; |
| struct inode *to_tell; |
| struct inotify_event_private_data *event_priv; |
| struct fsnotify_event_private_data *fsn_event_priv; |
| int wd, ret; |
| |
| to_tell = event->to_tell; |
| |
| spin_lock(&to_tell->i_lock); |
| entry = fsnotify_find_mark_entry(group, to_tell); |
| spin_unlock(&to_tell->i_lock); |
| /* race with watch removal? We already passes should_send */ |
| if (unlikely(!entry)) |
| return 0; |
| ientry = container_of(entry, struct inotify_inode_mark_entry, |
| fsn_entry); |
| wd = ientry->wd; |
| |
| event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); |
| if (unlikely(!event_priv)) |
| return -ENOMEM; |
| |
| fsn_event_priv = &event_priv->fsnotify_event_priv_data; |
| |
| fsn_event_priv->group = group; |
| event_priv->wd = wd; |
| |
| ret = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge); |
| if (ret) { |
| inotify_free_event_priv(fsn_event_priv); |
| /* EEXIST says we tail matched, EOVERFLOW isn't something |
| * to report up the stack. */ |
| if ((ret == -EEXIST) || |
| (ret == -EOVERFLOW)) |
| ret = 0; |
| } |
| |
| /* |
| * If we hold the entry until after the event is on the queue |
| * IN_IGNORED won't be able to pass this event in the queue |
| */ |
| fsnotify_put_mark(entry); |
| |
| return ret; |
| } |
| |
| static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) |
| { |
| inotify_ignored_and_remove_idr(entry, group); |
| } |
| |
| static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, |
| struct vfsmount *mnt, __u32 mask, void *data, |
| int data_type) |
| { |
| struct fsnotify_mark_entry *entry; |
| bool send; |
| |
| spin_lock(&inode->i_lock); |
| entry = fsnotify_find_mark_entry(group, inode); |
| spin_unlock(&inode->i_lock); |
| if (!entry) |
| return false; |
| |
| mask = (mask & ~FS_EVENT_ON_CHILD); |
| send = (entry->mask & mask); |
| |
| /* find took a reference */ |
| fsnotify_put_mark(entry); |
| |
| return send; |
| } |
| |
| /* |
| * This is NEVER supposed to be called. Inotify marks should either have been |
| * removed from the idr when the watch was removed or in the |
| * fsnotify_destroy_mark_by_group() call when the inotify instance was being |
| * torn down. This is only called if the idr is about to be freed but there |
| * are still marks in it. |
| */ |
| static int idr_callback(int id, void *p, void *data) |
| { |
| struct fsnotify_mark_entry *entry; |
| struct inotify_inode_mark_entry *ientry; |
| static bool warned = false; |
| |
| if (warned) |
| return 0; |
| |
| warned = true; |
| entry = p; |
| ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); |
| |
| WARN(1, "inotify closing but id=%d for entry=%p in group=%p still in " |
| "idr. Probably leaking memory\n", id, p, data); |
| |
| /* |
| * I'm taking the liberty of assuming that the mark in question is a |
| * valid address and I'm dereferencing it. This might help to figure |
| * out why we got here and the panic is no worse than the original |
| * BUG() that was here. |
| */ |
| if (entry) |
| printk(KERN_WARNING "entry->group=%p inode=%p wd=%d\n", |
| entry->group, entry->i.inode, ientry->wd); |
| return 0; |
| } |
| |
| static void inotify_free_group_priv(struct fsnotify_group *group) |
| { |
| /* ideally the idr is empty and we won't hit the BUG in teh callback */ |
| idr_for_each(&group->inotify_data.idr, idr_callback, group); |
| idr_remove_all(&group->inotify_data.idr); |
| idr_destroy(&group->inotify_data.idr); |
| free_uid(group->inotify_data.user); |
| } |
| |
| void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv) |
| { |
| struct inotify_event_private_data *event_priv; |
| |
| |
| event_priv = container_of(fsn_event_priv, struct inotify_event_private_data, |
| fsnotify_event_priv_data); |
| |
| kmem_cache_free(event_priv_cachep, event_priv); |
| } |
| |
| const struct fsnotify_ops inotify_fsnotify_ops = { |
| .handle_event = inotify_handle_event, |
| .should_send_event = inotify_should_send_event, |
| .free_group_priv = inotify_free_group_priv, |
| .free_event_priv = inotify_free_event_priv, |
| .freeing_mark = inotify_freeing_mark, |
| }; |