/* * fs/inotify_user.c - inotify support for userspace * * Authors: * John McCutchan * Robert Love * * Copyright (C) 2005 John McCutchan * Copyright 2006 Hewlett-Packard Development Company, L.P. * * Copyright (C) 2009 Eric Paris * 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 /* struct inode */ #include #include #include /* struct path */ #include /* kmem_* */ #include #include #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, void **arg) { 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 *fsn_mark; 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; int wd, ret; to_tell = event->to_tell; fsn_mark = fsnotify_find_inode_mark(group, to_tell); /* race with watch removal? We already passes should_send */ if (unlikely(!fsn_mark)) return 0; i_mark = container_of(fsn_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; ret = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge, NULL); 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 fsn_mark until after the event is on the queue * IN_IGNORED won't be able to pass this event in the queue */ fsnotify_put_mark(fsn_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, __u32 mask, void *data, int data_type) { struct fsnotify_mark *fsn_mark; bool send; fsn_mark = fsnotify_find_inode_mark(group, inode); if (!fsn_mark) return false; mask = (mask & ~FS_EVENT_ON_CHILD); send = (fsn_mark->mask & mask); /* find took a reference */ fsnotify_put_mark(fsn_mark); 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, };