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