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/dcache.h> /* d_unlinked */ 26 #include <linux/fs.h> /* struct inode */ 27 #include <linux/fsnotify_backend.h> 28 #include <linux/inotify.h> 29 #include <linux/path.h> /* struct path */ 30 #include <linux/slab.h> /* kmem_* */ 31 #include <linux/types.h> 32 #include <linux/sched.h> 33 34 #include "inotify.h" 35 36 /* 37 * Check if 2 events contain the same information. 38 */ 39 static bool event_compare(struct fsnotify_event *old_fsn, 40 struct fsnotify_event *new_fsn) 41 { 42 struct inotify_event_info *old, *new; 43 44 if (old_fsn->mask & FS_IN_IGNORED) 45 return false; 46 old = INOTIFY_E(old_fsn); 47 new = INOTIFY_E(new_fsn); 48 if ((old_fsn->mask == new_fsn->mask) && 49 (old_fsn->inode == new_fsn->inode) && 50 (old->name_len == new->name_len) && 51 (!old->name_len || !strcmp(old->name, new->name))) 52 return true; 53 return false; 54 } 55 56 static int inotify_merge(struct list_head *list, 57 struct fsnotify_event *event) 58 { 59 struct fsnotify_event *last_event; 60 61 last_event = list_entry(list->prev, struct fsnotify_event, list); 62 return event_compare(last_event, event); 63 } 64 65 int inotify_handle_event(struct fsnotify_group *group, 66 struct inode *inode, 67 struct fsnotify_mark *inode_mark, 68 struct fsnotify_mark *vfsmount_mark, 69 u32 mask, void *data, int data_type, 70 const unsigned char *file_name, u32 cookie) 71 { 72 struct inotify_inode_mark *i_mark; 73 struct inotify_event_info *event; 74 struct fsnotify_event *fsn_event; 75 int ret; 76 int len = 0; 77 int alloc_len = sizeof(struct inotify_event_info); 78 79 BUG_ON(vfsmount_mark); 80 81 if ((inode_mark->mask & FS_EXCL_UNLINK) && 82 (data_type == FSNOTIFY_EVENT_PATH)) { 83 struct path *path = data; 84 85 if (d_unlinked(path->dentry)) 86 return 0; 87 } 88 if (file_name) { 89 len = strlen(file_name); 90 alloc_len += len + 1; 91 } 92 93 pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, 94 mask); 95 96 i_mark = container_of(inode_mark, struct inotify_inode_mark, 97 fsn_mark); 98 99 event = kmalloc(alloc_len, GFP_KERNEL); 100 if (unlikely(!event)) 101 return -ENOMEM; 102 103 fsn_event = &event->fse; 104 fsnotify_init_event(fsn_event, inode, mask); 105 event->wd = i_mark->wd; 106 event->sync_cookie = cookie; 107 event->name_len = len; 108 if (len) 109 strcpy(event->name, file_name); 110 111 ret = fsnotify_add_event(group, fsn_event, inotify_merge); 112 if (ret) { 113 /* Our event wasn't used in the end. Free it. */ 114 fsnotify_destroy_event(group, fsn_event); 115 } 116 117 if (inode_mark->mask & IN_ONESHOT) 118 fsnotify_destroy_mark(inode_mark, group); 119 120 return 0; 121 } 122 123 static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group) 124 { 125 inotify_ignored_and_remove_idr(fsn_mark, group); 126 } 127 128 /* 129 * This is NEVER supposed to be called. Inotify marks should either have been 130 * removed from the idr when the watch was removed or in the 131 * fsnotify_destroy_mark_by_group() call when the inotify instance was being 132 * torn down. This is only called if the idr is about to be freed but there 133 * are still marks in it. 134 */ 135 static int idr_callback(int id, void *p, void *data) 136 { 137 struct fsnotify_mark *fsn_mark; 138 struct inotify_inode_mark *i_mark; 139 static bool warned = false; 140 141 if (warned) 142 return 0; 143 144 warned = true; 145 fsn_mark = p; 146 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); 147 148 WARN(1, "inotify closing but id=%d for fsn_mark=%p in group=%p still in " 149 "idr. Probably leaking memory\n", id, p, data); 150 151 /* 152 * I'm taking the liberty of assuming that the mark in question is a 153 * valid address and I'm dereferencing it. This might help to figure 154 * out why we got here and the panic is no worse than the original 155 * BUG() that was here. 156 */ 157 if (fsn_mark) 158 printk(KERN_WARNING "fsn_mark->group=%p inode=%p wd=%d\n", 159 fsn_mark->group, fsn_mark->inode, i_mark->wd); 160 return 0; 161 } 162 163 static void inotify_free_group_priv(struct fsnotify_group *group) 164 { 165 /* ideally the idr is empty and we won't hit the BUG in the callback */ 166 idr_for_each(&group->inotify_data.idr, idr_callback, group); 167 idr_destroy(&group->inotify_data.idr); 168 if (group->inotify_data.user) { 169 atomic_dec(&group->inotify_data.user->inotify_devs); 170 free_uid(group->inotify_data.user); 171 } 172 } 173 174 static void inotify_free_event(struct fsnotify_event *fsn_event) 175 { 176 kfree(INOTIFY_E(fsn_event)); 177 } 178 179 const struct fsnotify_ops inotify_fsnotify_ops = { 180 .handle_event = inotify_handle_event, 181 .free_group_priv = inotify_free_group_priv, 182 .free_event = inotify_free_event, 183 .freeing_mark = inotify_freeing_mark, 184 }; 185