| /* |
| * 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/dcache.h> /* d_unlinked */ |
| #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_FILE): |
| if ((old->file->f_path.mnt == new->file->f_path.mnt) && |
| (old->file->f_path.dentry == new->file->f_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 struct fsnotify_event *inotify_merge(struct list_head *list, |
| struct fsnotify_event *event) |
| { |
| struct fsnotify_event_holder *last_holder; |
| struct fsnotify_event *last_event; |
| |
| /* 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)) |
| fsnotify_get_event(last_event); |
| else |
| last_event = NULL; |
| |
| spin_unlock(&event->lock); |
| |
| return last_event; |
| } |
| |
| static int inotify_handle_event(struct fsnotify_group *group, |
| struct fsnotify_mark *mark, |
| struct fsnotify_event *event) |
| { |
| struct inotify_inode_mark *i_mark; |
| struct inode *to_tell; |
| struct inotify_event_private_data *event_priv; |
| struct fsnotify_event_private_data *fsn_event_priv; |
| struct fsnotify_event *added_event; |
| int wd, ret = 0; |
| |
| pr_debug("%s: group=%p event=%p to_tell=%p mask=%x\n", __func__, group, |
| event, event->to_tell, event->mask); |
| |
| to_tell = event->to_tell; |
| |
| i_mark = container_of(mark, struct inotify_inode_mark, |
| fsn_mark); |
| wd = i_mark->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; |
| |
| added_event = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge); |
| if (added_event) { |
| inotify_free_event_priv(fsn_event_priv); |
| if (!IS_ERR(added_event)) |
| fsnotify_put_event(added_event); |
| else |
| ret = PTR_ERR(added_event); |
| } |
| |
| if (mark->mask & IN_ONESHOT) |
| fsnotify_destroy_mark(mark); |
| |
| return ret; |
| } |
| |
| static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group) |
| { |
| inotify_ignored_and_remove_idr(fsn_mark, group); |
| } |
| |
| static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, |
| struct vfsmount *mnt, struct fsnotify_mark *mark, |
| __u32 mask, void *data, int data_type) |
| { |
| bool send; |
| |
| pr_debug("%s: group=%p inode=%p mask=%x data=%p data_type=%d\n", |
| __func__, group, inode, mask, data, data_type); |
| |
| mask = (mask & ~FS_EVENT_ON_CHILD); |
| send = (mark->mask & mask); |
| |
| if (send && (mark->mask & FS_EXCL_UNLINK) && |
| (data_type == FSNOTIFY_EVENT_FILE)) { |
| struct file *file = data; |
| |
| if (d_unlinked(file->f_path.dentry)) |
| send = false; |
| } |
| |
| 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 *fsn_mark; |
| struct inotify_inode_mark *i_mark; |
| static bool warned = false; |
| |
| if (warned) |
| return 0; |
| |
| warned = true; |
| fsn_mark = p; |
| i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); |
| |
| WARN(1, "inotify closing but id=%d for fsn_mark=%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 (fsn_mark) |
| printk(KERN_WARNING "fsn_mark->group=%p inode=%p wd=%d\n", |
| fsn_mark->group, fsn_mark->i.inode, i_mark->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, |
| }; |