1 /* 2 * fs/inotify_user.c - inotify support for userspace 3 * 4 * Authors: 5 * John McCutchan <ttb@tentacle.dhs.org> 6 * Robert Love <rml@novell.com> 7 * 8 * Copyright (C) 2005 John McCutchan 9 * Copyright 2006 Hewlett-Packard Development Company, L.P. 10 * 11 * Copyright (C) 2009 Eric Paris <Red Hat Inc> 12 * inotify was largely rewriten to make use of the fsnotify infrastructure 13 * 14 * This program is free software; you can redistribute it and/or modify it 15 * under the terms of the GNU General Public License as published by the 16 * Free Software Foundation; either version 2, or (at your option) any 17 * later version. 18 * 19 * This program is distributed in the hope that it will be useful, but 20 * WITHOUT ANY WARRANTY; without even the implied warranty of 21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 22 * General Public License for more details. 23 */ 24 25 #include <linux/fs.h> /* struct inode */ 26 #include <linux/fsnotify_backend.h> 27 #include <linux/inotify.h> 28 #include <linux/path.h> /* struct path */ 29 #include <linux/slab.h> /* kmem_* */ 30 #include <linux/types.h> 31 #include <linux/sched.h> 32 33 #include "inotify.h" 34 35 static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) 36 { 37 struct fsnotify_mark_entry *entry; 38 struct inotify_inode_mark_entry *ientry; 39 struct inode *to_tell; 40 struct inotify_event_private_data *event_priv; 41 struct fsnotify_event_private_data *fsn_event_priv; 42 int wd, ret; 43 44 to_tell = event->to_tell; 45 46 spin_lock(&to_tell->i_lock); 47 entry = fsnotify_find_mark_entry(group, to_tell); 48 spin_unlock(&to_tell->i_lock); 49 /* race with watch removal? We already passes should_send */ 50 if (unlikely(!entry)) 51 return 0; 52 ientry = container_of(entry, struct inotify_inode_mark_entry, 53 fsn_entry); 54 wd = ientry->wd; 55 56 event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); 57 if (unlikely(!event_priv)) 58 return -ENOMEM; 59 60 fsn_event_priv = &event_priv->fsnotify_event_priv_data; 61 62 fsn_event_priv->group = group; 63 event_priv->wd = wd; 64 65 ret = fsnotify_add_notify_event(group, event, fsn_event_priv); 66 if (ret) { 67 inotify_free_event_priv(fsn_event_priv); 68 /* EEXIST says we tail matched, EOVERFLOW isn't something 69 * to report up the stack. */ 70 if ((ret == -EEXIST) || 71 (ret == -EOVERFLOW)) 72 ret = 0; 73 } 74 75 /* 76 * If we hold the entry until after the event is on the queue 77 * IN_IGNORED won't be able to pass this event in the queue 78 */ 79 fsnotify_put_mark(entry); 80 81 return ret; 82 } 83 84 static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) 85 { 86 inotify_ignored_and_remove_idr(entry, group); 87 } 88 89 static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask) 90 { 91 struct fsnotify_mark_entry *entry; 92 bool send; 93 94 spin_lock(&inode->i_lock); 95 entry = fsnotify_find_mark_entry(group, inode); 96 spin_unlock(&inode->i_lock); 97 if (!entry) 98 return false; 99 100 mask = (mask & ~FS_EVENT_ON_CHILD); 101 send = (entry->mask & mask); 102 103 /* find took a reference */ 104 fsnotify_put_mark(entry); 105 106 return send; 107 } 108 109 /* 110 * This is NEVER supposed to be called. Inotify marks should either have been 111 * removed from the idr when the watch was removed or in the 112 * fsnotify_destroy_mark_by_group() call when the inotify instance was being 113 * torn down. This is only called if the idr is about to be freed but there 114 * are still marks in it. 115 */ 116 static int idr_callback(int id, void *p, void *data) 117 { 118 struct fsnotify_mark_entry *entry; 119 struct inotify_inode_mark_entry *ientry; 120 static bool warned = false; 121 122 if (warned) 123 return 0; 124 125 warned = true; 126 entry = p; 127 ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); 128 129 WARN(1, "inotify closing but id=%d for entry=%p in group=%p still in " 130 "idr. Probably leaking memory\n", id, p, data); 131 132 /* 133 * I'm taking the liberty of assuming that the mark in question is a 134 * valid address and I'm dereferencing it. This might help to figure 135 * out why we got here and the panic is no worse than the original 136 * BUG() that was here. 137 */ 138 if (entry) 139 printk(KERN_WARNING "entry->group=%p inode=%p wd=%d\n", 140 entry->group, entry->inode, ientry->wd); 141 return 0; 142 } 143 144 static void inotify_free_group_priv(struct fsnotify_group *group) 145 { 146 /* ideally the idr is empty and we won't hit the BUG in teh callback */ 147 idr_for_each(&group->inotify_data.idr, idr_callback, group); 148 idr_remove_all(&group->inotify_data.idr); 149 idr_destroy(&group->inotify_data.idr); 150 free_uid(group->inotify_data.user); 151 } 152 153 void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv) 154 { 155 struct inotify_event_private_data *event_priv; 156 157 158 event_priv = container_of(fsn_event_priv, struct inotify_event_private_data, 159 fsnotify_event_priv_data); 160 161 kmem_cache_free(event_priv_cachep, event_priv); 162 } 163 164 const struct fsnotify_ops inotify_fsnotify_ops = { 165 .handle_event = inotify_handle_event, 166 .should_send_event = inotify_should_send_event, 167 .free_group_priv = inotify_free_group_priv, 168 .free_event_priv = inotify_free_event_priv, 169 .freeing_mark = inotify_freeing_mark, 170 }; 171