]>
Commit | Line | Data |
---|---|---|
33d3dfff | 1 | #include <linux/fanotify.h> |
ff0b16a9 EP |
2 | #include <linux/fdtable.h> |
3 | #include <linux/fsnotify_backend.h> | |
4 | #include <linux/init.h> | |
9e66e423 | 5 | #include <linux/jiffies.h> |
ff0b16a9 | 6 | #include <linux/kernel.h> /* UINT_MAX */ |
1c529063 | 7 | #include <linux/mount.h> |
9e66e423 | 8 | #include <linux/sched.h> |
ff0b16a9 | 9 | #include <linux/types.h> |
9e66e423 | 10 | #include <linux/wait.h> |
ff0b16a9 | 11 | |
767cd46c EP |
12 | static bool should_merge(struct fsnotify_event *old, struct fsnotify_event *new) |
13 | { | |
14 | pr_debug("%s: old=%p new=%p\n", __func__, old, new); | |
15 | ||
32c32632 AG |
16 | if (old->to_tell == new->to_tell && |
17 | old->data_type == new->data_type && | |
18 | old->tgid == new->tgid) { | |
767cd46c | 19 | switch (old->data_type) { |
3bcf3860 EP |
20 | case (FSNOTIFY_EVENT_FILE): |
21 | if ((old->file->f_path.mnt == new->file->f_path.mnt) && | |
22 | (old->file->f_path.dentry == new->file->f_path.dentry)) | |
767cd46c EP |
23 | return true; |
24 | case (FSNOTIFY_EVENT_NONE): | |
25 | return true; | |
26 | default: | |
27 | BUG(); | |
28 | }; | |
29 | } | |
30 | return false; | |
31 | } | |
32 | ||
f70ab54c EP |
33 | /* and the list better be locked by something too! */ |
34 | static struct fsnotify_event *fanotify_merge(struct list_head *list, | |
35 | struct fsnotify_event *event) | |
767cd46c | 36 | { |
a12a7dd3 | 37 | struct fsnotify_event_holder *test_holder; |
f70ab54c | 38 | struct fsnotify_event *test_event = NULL; |
a12a7dd3 | 39 | struct fsnotify_event *new_event; |
767cd46c EP |
40 | |
41 | pr_debug("%s: list=%p event=%p\n", __func__, list, event); | |
42 | ||
767cd46c | 43 | |
a12a7dd3 | 44 | list_for_each_entry_reverse(test_holder, list, event_list) { |
f70ab54c EP |
45 | if (should_merge(test_holder->event, event)) { |
46 | test_event = test_holder->event; | |
a12a7dd3 EP |
47 | break; |
48 | } | |
49 | } | |
f70ab54c EP |
50 | |
51 | if (!test_event) | |
52 | return NULL; | |
53 | ||
54 | fsnotify_get_event(test_event); | |
55 | ||
56 | /* if they are exactly the same we are done */ | |
57 | if (test_event->mask == event->mask) | |
58 | return test_event; | |
59 | ||
60 | /* | |
61 | * if the refcnt == 2 this is the only queue | |
62 | * for this event and so we can update the mask | |
63 | * in place. | |
64 | */ | |
65 | if (atomic_read(&test_event->refcnt) == 2) { | |
66 | test_event->mask |= event->mask; | |
67 | return test_event; | |
68 | } | |
69 | ||
70 | new_event = fsnotify_clone_event(test_event); | |
71 | ||
72 | /* done with test_event */ | |
73 | fsnotify_put_event(test_event); | |
74 | ||
75 | /* couldn't allocate memory, merge was not possible */ | |
76 | if (unlikely(!new_event)) | |
77 | return ERR_PTR(-ENOMEM); | |
78 | ||
79 | /* build new event and replace it on the list */ | |
80 | new_event->mask = (test_event->mask | event->mask); | |
81 | fsnotify_replace_event(test_holder, new_event); | |
82 | ||
83 | /* we hold a reference on new_event from clone_event */ | |
84 | return new_event; | |
767cd46c EP |
85 | } |
86 | ||
9e66e423 EP |
87 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
88 | static int fanotify_get_response_from_access(struct fsnotify_group *group, | |
89 | struct fsnotify_event *event) | |
90 | { | |
91 | int ret; | |
92 | ||
93 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); | |
94 | ||
95 | wait_event(group->fanotify_data.access_waitq, event->response); | |
96 | ||
97 | /* userspace responded, convert to something usable */ | |
98 | spin_lock(&event->lock); | |
99 | switch (event->response) { | |
100 | case FAN_ALLOW: | |
101 | ret = 0; | |
102 | break; | |
103 | case FAN_DENY: | |
104 | default: | |
105 | ret = -EPERM; | |
106 | } | |
107 | event->response = 0; | |
108 | spin_unlock(&event->lock); | |
109 | ||
b2d87909 EP |
110 | pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, |
111 | group, event, ret); | |
112 | ||
9e66e423 EP |
113 | return ret; |
114 | } | |
115 | #endif | |
116 | ||
3a9b16b4 EP |
117 | static int fanotify_handle_event(struct fsnotify_group *group, |
118 | struct fsnotify_mark *mark, | |
119 | struct fsnotify_event *event) | |
ff0b16a9 | 120 | { |
f70ab54c | 121 | int ret = 0; |
9e66e423 | 122 | struct fsnotify_event *notify_event = NULL; |
ff0b16a9 EP |
123 | |
124 | BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); | |
125 | BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); | |
126 | BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); | |
127 | BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); | |
128 | BUILD_BUG_ON(FAN_OPEN != FS_OPEN); | |
129 | BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); | |
130 | BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW); | |
9e66e423 EP |
131 | BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM); |
132 | BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM); | |
ff0b16a9 EP |
133 | |
134 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); | |
135 | ||
f70ab54c EP |
136 | notify_event = fsnotify_add_notify_event(group, event, NULL, fanotify_merge); |
137 | if (IS_ERR(notify_event)) | |
138 | return PTR_ERR(notify_event); | |
9e66e423 EP |
139 | |
140 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
141 | if (event->mask & FAN_ALL_PERM_EVENTS) { | |
142 | /* if we merged we need to wait on the new event */ | |
143 | if (notify_event) | |
144 | event = notify_event; | |
145 | ret = fanotify_get_response_from_access(group, event); | |
146 | } | |
147 | #endif | |
148 | ||
9e66e423 EP |
149 | if (notify_event) |
150 | fsnotify_put_event(notify_event); | |
f70ab54c | 151 | |
ff0b16a9 EP |
152 | return ret; |
153 | } | |
154 | ||
1c529063 | 155 | static bool should_send_vfsmount_event(struct fsnotify_group *group, struct vfsmount *mnt, |
32a4df13 | 156 | struct inode *inode, __u32 mask) |
ff0b16a9 | 157 | { |
32a4df13 EP |
158 | struct fsnotify_mark *mnt_mark; |
159 | struct fsnotify_mark *inode_mark; | |
ff0b16a9 | 160 | |
1c529063 EP |
161 | pr_debug("%s: group=%p vfsmount=%p mask=%x\n", |
162 | __func__, group, mnt, mask); | |
ff0b16a9 | 163 | |
32a4df13 EP |
164 | mnt_mark = fsnotify_find_vfsmount_mark(group, mnt); |
165 | if (!mnt_mark) | |
ff0b16a9 EP |
166 | return false; |
167 | ||
32a4df13 EP |
168 | mask &= mnt_mark->mask; |
169 | mask &= ~mnt_mark->ignored_mask; | |
170 | ||
171 | if (mask) { | |
172 | inode_mark = fsnotify_find_inode_mark(group, inode); | |
173 | if (inode_mark) { | |
174 | mask &= ~inode_mark->ignored_mask; | |
175 | fsnotify_put_mark(inode_mark); | |
176 | } | |
177 | } | |
1c529063 EP |
178 | |
179 | /* find took a reference */ | |
32a4df13 | 180 | fsnotify_put_mark(mnt_mark); |
1c529063 | 181 | |
32a4df13 | 182 | return mask; |
1c529063 EP |
183 | } |
184 | ||
185 | static bool should_send_inode_event(struct fsnotify_group *group, struct inode *inode, | |
186 | __u32 mask) | |
187 | { | |
188 | struct fsnotify_mark *fsn_mark; | |
1c529063 EP |
189 | |
190 | pr_debug("%s: group=%p inode=%p mask=%x\n", | |
191 | __func__, group, inode, mask); | |
ff0b16a9 | 192 | |
5444e298 | 193 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
ff0b16a9 EP |
194 | if (!fsn_mark) |
195 | return false; | |
196 | ||
197 | /* if the event is for a child and this inode doesn't care about | |
198 | * events on the child, don't send it! */ | |
199 | if ((mask & FS_EVENT_ON_CHILD) && | |
200 | !(fsn_mark->mask & FS_EVENT_ON_CHILD)) { | |
32a4df13 | 201 | mask = 0; |
ff0b16a9 EP |
202 | } else { |
203 | /* | |
204 | * We care about children, but do we care about this particular | |
205 | * type of event? | |
206 | */ | |
32a4df13 EP |
207 | mask &= ~FS_EVENT_ON_CHILD; |
208 | mask &= fsn_mark->mask; | |
209 | mask &= ~fsn_mark->ignored_mask; | |
ff0b16a9 EP |
210 | } |
211 | ||
212 | /* find took a reference */ | |
213 | fsnotify_put_mark(fsn_mark); | |
214 | ||
32a4df13 | 215 | return mask; |
ff0b16a9 EP |
216 | } |
217 | ||
1c529063 | 218 | static bool fanotify_should_send_event(struct fsnotify_group *group, struct inode *to_tell, |
3a9b16b4 EP |
219 | struct vfsmount *mnt, struct fsnotify_mark *mark, |
220 | __u32 mask, void *data, int data_type) | |
1c529063 EP |
221 | { |
222 | pr_debug("%s: group=%p to_tell=%p mnt=%p mask=%x data=%p data_type=%d\n", | |
223 | __func__, group, to_tell, mnt, mask, data, data_type); | |
224 | ||
225 | /* sorry, fanotify only gives a damn about files and dirs */ | |
226 | if (!S_ISREG(to_tell->i_mode) && | |
227 | !S_ISDIR(to_tell->i_mode)) | |
228 | return false; | |
229 | ||
230 | /* if we don't have enough info to send an event to userspace say no */ | |
3bcf3860 | 231 | if (data_type != FSNOTIFY_EVENT_FILE) |
1c529063 EP |
232 | return false; |
233 | ||
234 | if (mnt) | |
32a4df13 | 235 | return should_send_vfsmount_event(group, mnt, to_tell, mask); |
1c529063 EP |
236 | else |
237 | return should_send_inode_event(group, to_tell, mask); | |
238 | } | |
239 | ||
ff0b16a9 EP |
240 | const struct fsnotify_ops fanotify_fsnotify_ops = { |
241 | .handle_event = fanotify_handle_event, | |
242 | .should_send_event = fanotify_should_send_event, | |
243 | .free_group_priv = NULL, | |
244 | .free_event_priv = NULL, | |
245 | .freeing_mark = NULL, | |
246 | }; |