1 #include <linux/fdtable.h>
2 #include <linux/fsnotify_backend.h>
3 #include <linux/init.h>
4 #include <linux/kernel.h> /* UINT_MAX */
5 #include <linux/mount.h>
6 #include <linux/types.h>
10 static bool should_merge(struct fsnotify_event *old, struct fsnotify_event *new)
12 pr_debug("%s: old=%p new=%p\n", __func__, old, new);
14 if (old->to_tell == new->to_tell &&
15 old->data_type == new->data_type &&
16 old->tgid == new->tgid) {
17 switch (old->data_type) {
18 case (FSNOTIFY_EVENT_PATH):
19 if ((old->path.mnt == new->path.mnt) &&
20 (old->path.dentry == new->path.dentry))
22 case (FSNOTIFY_EVENT_NONE):
31 static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
33 struct fsnotify_event_holder *test_holder;
34 struct fsnotify_event *test_event;
35 struct fsnotify_event *new_event;
38 pr_debug("%s: list=%p event=%p\n", __func__, list, event);
40 /* and the list better be locked by something too! */
42 list_for_each_entry_reverse(test_holder, list, event_list) {
43 test_event = test_holder->event;
44 if (should_merge(test_event, event)) {
47 /* if they are exactly the same we are done */
48 if (test_event->mask == event->mask)
52 * if the refcnt == 1 this is the only queue
53 * for this event and so we can update the mask
56 if (atomic_read(&test_event->refcnt) == 1) {
57 test_event->mask |= event->mask;
61 /* can't allocate memory, merge was no possible */
62 new_event = fsnotify_clone_event(test_event);
63 if (unlikely(!new_event)) {
68 /* build new event and replace it on the list */
69 new_event->mask = (test_event->mask | event->mask);
70 fsnotify_replace_event(test_holder, new_event);
71 /* match ref from fsnotify_clone_event() */
72 fsnotify_put_event(new_event);
81 static int fanotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
86 BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS);
87 BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY);
88 BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
89 BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE);
90 BUILD_BUG_ON(FAN_OPEN != FS_OPEN);
91 BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD);
92 BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW);
94 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
96 ret = fsnotify_add_notify_event(group, event, NULL, fanotify_merge);
97 /* -EEXIST means this event was merged with another, not that it was an error */
103 static bool should_send_vfsmount_event(struct fsnotify_group *group, struct vfsmount *mnt,
106 struct fsnotify_mark *fsn_mark;
109 pr_debug("%s: group=%p vfsmount=%p mask=%x\n",
110 __func__, group, mnt, mask);
112 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
116 send = (mask & fsn_mark->mask);
118 /* find took a reference */
119 fsnotify_put_mark(fsn_mark);
124 static bool should_send_inode_event(struct fsnotify_group *group, struct inode *inode,
127 struct fsnotify_mark *fsn_mark;
130 pr_debug("%s: group=%p inode=%p mask=%x\n",
131 __func__, group, inode, mask);
133 fsn_mark = fsnotify_find_inode_mark(group, inode);
137 /* if the event is for a child and this inode doesn't care about
138 * events on the child, don't send it! */
139 if ((mask & FS_EVENT_ON_CHILD) &&
140 !(fsn_mark->mask & FS_EVENT_ON_CHILD)) {
144 * We care about children, but do we care about this particular
147 mask = (mask & ~FS_EVENT_ON_CHILD);
148 send = (fsn_mark->mask & mask);
151 /* find took a reference */
152 fsnotify_put_mark(fsn_mark);
157 static bool fanotify_should_send_event(struct fsnotify_group *group, struct inode *to_tell,
158 struct vfsmount *mnt, __u32 mask, void *data,
161 pr_debug("%s: group=%p to_tell=%p mnt=%p mask=%x data=%p data_type=%d\n",
162 __func__, group, to_tell, mnt, mask, data, data_type);
164 /* sorry, fanotify only gives a damn about files and dirs */
165 if (!S_ISREG(to_tell->i_mode) &&
166 !S_ISDIR(to_tell->i_mode))
169 /* if we don't have enough info to send an event to userspace say no */
170 if (data_type != FSNOTIFY_EVENT_PATH)
174 return should_send_vfsmount_event(group, mnt, mask);
176 return should_send_inode_event(group, to_tell, mask);
179 const struct fsnotify_ops fanotify_fsnotify_ops = {
180 .handle_event = fanotify_handle_event,
181 .should_send_event = fanotify_should_send_event,
182 .free_group_priv = NULL,
183 .free_event_priv = NULL,
184 .freeing_mark = NULL,