Commit | Line | Data |
---|---|---|
77b14db5 EB |
1 | /* |
2 | * /proc/sys support | |
3 | */ | |
1e0edd3f | 4 | #include <linux/init.h> |
77b14db5 | 5 | #include <linux/sysctl.h> |
f1ecf068 | 6 | #include <linux/poll.h> |
77b14db5 | 7 | #include <linux/proc_fs.h> |
87ebdc00 | 8 | #include <linux/printk.h> |
77b14db5 | 9 | #include <linux/security.h> |
40401530 | 10 | #include <linux/sched.h> |
34286d66 | 11 | #include <linux/namei.h> |
40401530 | 12 | #include <linux/mm.h> |
1f87f0b5 | 13 | #include <linux/module.h> |
77b14db5 EB |
14 | #include "internal.h" |
15 | ||
d72f71eb | 16 | static const struct dentry_operations proc_sys_dentry_operations; |
77b14db5 | 17 | static const struct file_operations proc_sys_file_operations; |
03a44825 | 18 | static const struct inode_operations proc_sys_inode_operations; |
9043476f AV |
19 | static const struct file_operations proc_sys_dir_file_operations; |
20 | static const struct inode_operations proc_sys_dir_operations; | |
77b14db5 | 21 | |
f1ecf068 LDM |
22 | void proc_sys_poll_notify(struct ctl_table_poll *poll) |
23 | { | |
24 | if (!poll) | |
25 | return; | |
26 | ||
27 | atomic_inc(&poll->event); | |
28 | wake_up_interruptible(&poll->wait); | |
29 | } | |
30 | ||
a194558e EB |
31 | static struct ctl_table root_table[] = { |
32 | { | |
33 | .procname = "", | |
7ec66d06 | 34 | .mode = S_IFDIR|S_IRUGO|S_IXUGO, |
a194558e EB |
35 | }, |
36 | { } | |
37 | }; | |
0e47c99d | 38 | static struct ctl_table_root sysctl_table_root = { |
0e47c99d | 39 | .default_set.dir.header = { |
7ec66d06 EB |
40 | {{.count = 1, |
41 | .nreg = 1, | |
ac13ac6f | 42 | .ctl_table = root_table }}, |
0e47c99d | 43 | .ctl_table_arg = root_table, |
7ec66d06 EB |
44 | .root = &sysctl_table_root, |
45 | .set = &sysctl_table_root.default_set, | |
46 | }, | |
1f87f0b5 | 47 | }; |
1f87f0b5 EB |
48 | |
49 | static DEFINE_SPINLOCK(sysctl_lock); | |
50 | ||
7ec66d06 | 51 | static void drop_sysctl_table(struct ctl_table_header *header); |
0e47c99d EB |
52 | static int sysctl_follow_link(struct ctl_table_header **phead, |
53 | struct ctl_table **pentry, struct nsproxy *namespaces); | |
54 | static int insert_links(struct ctl_table_header *head); | |
55 | static void put_links(struct ctl_table_header *header); | |
7ec66d06 | 56 | |
6980128f EB |
57 | static void sysctl_print_dir(struct ctl_dir *dir) |
58 | { | |
59 | if (dir->header.parent) | |
60 | sysctl_print_dir(dir->header.parent); | |
87ebdc00 | 61 | pr_cont("%s/", dir->header.ctl_table[0].procname); |
6980128f EB |
62 | } |
63 | ||
076c3eed EB |
64 | static int namecmp(const char *name1, int len1, const char *name2, int len2) |
65 | { | |
66 | int minlen; | |
67 | int cmp; | |
68 | ||
69 | minlen = len1; | |
70 | if (minlen > len2) | |
71 | minlen = len2; | |
72 | ||
73 | cmp = memcmp(name1, name2, minlen); | |
74 | if (cmp == 0) | |
75 | cmp = len1 - len2; | |
76 | return cmp; | |
77 | } | |
78 | ||
60f126d9 | 79 | /* Called under sysctl_lock */ |
076c3eed | 80 | static struct ctl_table *find_entry(struct ctl_table_header **phead, |
0e47c99d | 81 | struct ctl_dir *dir, const char *name, int namelen) |
076c3eed EB |
82 | { |
83 | struct ctl_table_header *head; | |
84 | struct ctl_table *entry; | |
ac13ac6f | 85 | struct rb_node *node = dir->root.rb_node; |
076c3eed | 86 | |
ac13ac6f EB |
87 | while (node) |
88 | { | |
89 | struct ctl_node *ctl_node; | |
90 | const char *procname; | |
91 | int cmp; | |
92 | ||
93 | ctl_node = rb_entry(node, struct ctl_node, node); | |
94 | head = ctl_node->header; | |
95 | entry = &head->ctl_table[ctl_node - head->node]; | |
96 | procname = entry->procname; | |
97 | ||
98 | cmp = namecmp(name, namelen, procname, strlen(procname)); | |
99 | if (cmp < 0) | |
100 | node = node->rb_left; | |
101 | else if (cmp > 0) | |
102 | node = node->rb_right; | |
103 | else { | |
104 | *phead = head; | |
105 | return entry; | |
076c3eed EB |
106 | } |
107 | } | |
108 | return NULL; | |
109 | } | |
110 | ||
ac13ac6f EB |
111 | static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) |
112 | { | |
113 | struct rb_node *node = &head->node[entry - head->ctl_table].node; | |
114 | struct rb_node **p = &head->parent->root.rb_node; | |
115 | struct rb_node *parent = NULL; | |
116 | const char *name = entry->procname; | |
117 | int namelen = strlen(name); | |
118 | ||
119 | while (*p) { | |
120 | struct ctl_table_header *parent_head; | |
121 | struct ctl_table *parent_entry; | |
122 | struct ctl_node *parent_node; | |
123 | const char *parent_name; | |
124 | int cmp; | |
125 | ||
126 | parent = *p; | |
127 | parent_node = rb_entry(parent, struct ctl_node, node); | |
128 | parent_head = parent_node->header; | |
129 | parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; | |
130 | parent_name = parent_entry->procname; | |
131 | ||
132 | cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); | |
133 | if (cmp < 0) | |
134 | p = &(*p)->rb_left; | |
135 | else if (cmp > 0) | |
136 | p = &(*p)->rb_right; | |
137 | else { | |
87ebdc00 | 138 | pr_err("sysctl duplicate entry: "); |
ac13ac6f | 139 | sysctl_print_dir(head->parent); |
87ebdc00 | 140 | pr_cont("/%s\n", entry->procname); |
ac13ac6f EB |
141 | return -EEXIST; |
142 | } | |
143 | } | |
144 | ||
145 | rb_link_node(node, parent, p); | |
ea5272f5 | 146 | rb_insert_color(node, &head->parent->root); |
ac13ac6f EB |
147 | return 0; |
148 | } | |
149 | ||
150 | static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) | |
151 | { | |
152 | struct rb_node *node = &head->node[entry - head->ctl_table].node; | |
153 | ||
154 | rb_erase(node, &head->parent->root); | |
155 | } | |
156 | ||
e0d04529 EB |
157 | static void init_header(struct ctl_table_header *head, |
158 | struct ctl_table_root *root, struct ctl_table_set *set, | |
ac13ac6f | 159 | struct ctl_node *node, struct ctl_table *table) |
e0d04529 | 160 | { |
7ec66d06 | 161 | head->ctl_table = table; |
e0d04529 | 162 | head->ctl_table_arg = table; |
e0d04529 EB |
163 | head->used = 0; |
164 | head->count = 1; | |
165 | head->nreg = 1; | |
166 | head->unregistering = NULL; | |
167 | head->root = root; | |
168 | head->set = set; | |
169 | head->parent = NULL; | |
ac13ac6f EB |
170 | head->node = node; |
171 | if (node) { | |
172 | struct ctl_table *entry; | |
4c199a93 | 173 | for (entry = table; entry->procname; entry++, node++) |
ac13ac6f | 174 | node->header = head; |
ac13ac6f | 175 | } |
e0d04529 EB |
176 | } |
177 | ||
8425d6aa EB |
178 | static void erase_header(struct ctl_table_header *head) |
179 | { | |
ac13ac6f EB |
180 | struct ctl_table *entry; |
181 | for (entry = head->ctl_table; entry->procname; entry++) | |
182 | erase_entry(head, entry); | |
8425d6aa EB |
183 | } |
184 | ||
0e47c99d | 185 | static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) |
8425d6aa | 186 | { |
ac13ac6f | 187 | struct ctl_table *entry; |
0e47c99d EB |
188 | int err; |
189 | ||
190 | dir->header.nreg++; | |
7ec66d06 | 191 | header->parent = dir; |
0e47c99d EB |
192 | err = insert_links(header); |
193 | if (err) | |
194 | goto fail_links; | |
ac13ac6f EB |
195 | for (entry = header->ctl_table; entry->procname; entry++) { |
196 | err = insert_entry(header, entry); | |
197 | if (err) | |
198 | goto fail; | |
199 | } | |
0e47c99d | 200 | return 0; |
ac13ac6f EB |
201 | fail: |
202 | erase_header(header); | |
203 | put_links(header); | |
0e47c99d EB |
204 | fail_links: |
205 | header->parent = NULL; | |
206 | drop_sysctl_table(&dir->header); | |
207 | return err; | |
8425d6aa EB |
208 | } |
209 | ||
1f87f0b5 EB |
210 | /* called under sysctl_lock */ |
211 | static int use_table(struct ctl_table_header *p) | |
212 | { | |
213 | if (unlikely(p->unregistering)) | |
214 | return 0; | |
215 | p->used++; | |
216 | return 1; | |
217 | } | |
218 | ||
219 | /* called under sysctl_lock */ | |
220 | static void unuse_table(struct ctl_table_header *p) | |
221 | { | |
222 | if (!--p->used) | |
223 | if (unlikely(p->unregistering)) | |
224 | complete(p->unregistering); | |
225 | } | |
226 | ||
227 | /* called under sysctl_lock, will reacquire if has to wait */ | |
228 | static void start_unregistering(struct ctl_table_header *p) | |
229 | { | |
230 | /* | |
231 | * if p->used is 0, nobody will ever touch that entry again; | |
232 | * we'll eliminate all paths to it before dropping sysctl_lock | |
233 | */ | |
234 | if (unlikely(p->used)) { | |
235 | struct completion wait; | |
236 | init_completion(&wait); | |
237 | p->unregistering = &wait; | |
238 | spin_unlock(&sysctl_lock); | |
239 | wait_for_completion(&wait); | |
240 | spin_lock(&sysctl_lock); | |
241 | } else { | |
242 | /* anything non-NULL; we'll never dereference it */ | |
243 | p->unregistering = ERR_PTR(-EINVAL); | |
244 | } | |
245 | /* | |
246 | * do not remove from the list until nobody holds it; walking the | |
247 | * list in do_sysctl() relies on that. | |
248 | */ | |
8425d6aa | 249 | erase_header(p); |
1f87f0b5 EB |
250 | } |
251 | ||
252 | static void sysctl_head_get(struct ctl_table_header *head) | |
253 | { | |
254 | spin_lock(&sysctl_lock); | |
255 | head->count++; | |
256 | spin_unlock(&sysctl_lock); | |
257 | } | |
258 | ||
259 | void sysctl_head_put(struct ctl_table_header *head) | |
260 | { | |
261 | spin_lock(&sysctl_lock); | |
262 | if (!--head->count) | |
263 | kfree_rcu(head, rcu); | |
264 | spin_unlock(&sysctl_lock); | |
265 | } | |
266 | ||
267 | static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) | |
268 | { | |
ab4a1f24 | 269 | BUG_ON(!head); |
1f87f0b5 EB |
270 | spin_lock(&sysctl_lock); |
271 | if (!use_table(head)) | |
272 | head = ERR_PTR(-ENOENT); | |
273 | spin_unlock(&sysctl_lock); | |
274 | return head; | |
275 | } | |
276 | ||
277 | static void sysctl_head_finish(struct ctl_table_header *head) | |
278 | { | |
279 | if (!head) | |
280 | return; | |
281 | spin_lock(&sysctl_lock); | |
282 | unuse_table(head); | |
283 | spin_unlock(&sysctl_lock); | |
284 | } | |
285 | ||
286 | static struct ctl_table_set * | |
287 | lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces) | |
288 | { | |
289 | struct ctl_table_set *set = &root->default_set; | |
290 | if (root->lookup) | |
291 | set = root->lookup(root, namespaces); | |
292 | return set; | |
293 | } | |
294 | ||
076c3eed | 295 | static struct ctl_table *lookup_entry(struct ctl_table_header **phead, |
7ec66d06 | 296 | struct ctl_dir *dir, |
076c3eed EB |
297 | const char *name, int namelen) |
298 | { | |
299 | struct ctl_table_header *head; | |
300 | struct ctl_table *entry; | |
076c3eed EB |
301 | |
302 | spin_lock(&sysctl_lock); | |
0e47c99d EB |
303 | entry = find_entry(&head, dir, name, namelen); |
304 | if (entry && use_table(head)) | |
305 | *phead = head; | |
306 | else | |
307 | entry = NULL; | |
076c3eed EB |
308 | spin_unlock(&sysctl_lock); |
309 | return entry; | |
310 | } | |
311 | ||
ac13ac6f | 312 | static struct ctl_node *first_usable_entry(struct rb_node *node) |
1f87f0b5 | 313 | { |
ac13ac6f | 314 | struct ctl_node *ctl_node; |
1f87f0b5 | 315 | |
ac13ac6f EB |
316 | for (;node; node = rb_next(node)) { |
317 | ctl_node = rb_entry(node, struct ctl_node, node); | |
318 | if (use_table(ctl_node->header)) | |
319 | return ctl_node; | |
1f87f0b5 | 320 | } |
1f87f0b5 EB |
321 | return NULL; |
322 | } | |
323 | ||
7ec66d06 | 324 | static void first_entry(struct ctl_dir *dir, |
6a75ce16 EB |
325 | struct ctl_table_header **phead, struct ctl_table **pentry) |
326 | { | |
ac13ac6f | 327 | struct ctl_table_header *head = NULL; |
7ec66d06 | 328 | struct ctl_table *entry = NULL; |
ac13ac6f | 329 | struct ctl_node *ctl_node; |
6a75ce16 EB |
330 | |
331 | spin_lock(&sysctl_lock); | |
ac13ac6f | 332 | ctl_node = first_usable_entry(rb_first(&dir->root)); |
6a75ce16 | 333 | spin_unlock(&sysctl_lock); |
ac13ac6f EB |
334 | if (ctl_node) { |
335 | head = ctl_node->header; | |
336 | entry = &head->ctl_table[ctl_node - head->node]; | |
337 | } | |
6a75ce16 EB |
338 | *phead = head; |
339 | *pentry = entry; | |
340 | } | |
341 | ||
7ec66d06 | 342 | static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) |
1f87f0b5 | 343 | { |
6a75ce16 EB |
344 | struct ctl_table_header *head = *phead; |
345 | struct ctl_table *entry = *pentry; | |
ac13ac6f | 346 | struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; |
6a75ce16 | 347 | |
ac13ac6f EB |
348 | spin_lock(&sysctl_lock); |
349 | unuse_table(head); | |
350 | ||
351 | ctl_node = first_usable_entry(rb_next(&ctl_node->node)); | |
352 | spin_unlock(&sysctl_lock); | |
353 | head = NULL; | |
354 | if (ctl_node) { | |
355 | head = ctl_node->header; | |
356 | entry = &head->ctl_table[ctl_node - head->node]; | |
6a75ce16 EB |
357 | } |
358 | *phead = head; | |
359 | *pentry = entry; | |
1f87f0b5 EB |
360 | } |
361 | ||
362 | void register_sysctl_root(struct ctl_table_root *root) | |
363 | { | |
1f87f0b5 EB |
364 | } |
365 | ||
366 | /* | |
367 | * sysctl_perm does NOT grant the superuser all rights automatically, because | |
368 | * some sysctl variables are readonly even to root. | |
369 | */ | |
370 | ||
371 | static int test_perm(int mode, int op) | |
372 | { | |
091bd3ea | 373 | if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) |
1f87f0b5 | 374 | mode >>= 6; |
091bd3ea | 375 | else if (in_egroup_p(GLOBAL_ROOT_GID)) |
1f87f0b5 EB |
376 | mode >>= 3; |
377 | if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) | |
378 | return 0; | |
379 | return -EACCES; | |
380 | } | |
381 | ||
73f7ef43 | 382 | static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) |
1f87f0b5 | 383 | { |
73f7ef43 | 384 | struct ctl_table_root *root = head->root; |
1f87f0b5 EB |
385 | int mode; |
386 | ||
387 | if (root->permissions) | |
73f7ef43 | 388 | mode = root->permissions(head, table); |
1f87f0b5 EB |
389 | else |
390 | mode = table->mode; | |
391 | ||
392 | return test_perm(mode, op); | |
393 | } | |
394 | ||
9043476f AV |
395 | static struct inode *proc_sys_make_inode(struct super_block *sb, |
396 | struct ctl_table_header *head, struct ctl_table *table) | |
77b14db5 EB |
397 | { |
398 | struct inode *inode; | |
9043476f | 399 | struct proc_inode *ei; |
77b14db5 | 400 | |
9043476f | 401 | inode = new_inode(sb); |
77b14db5 EB |
402 | if (!inode) |
403 | goto out; | |
404 | ||
85fe4025 CH |
405 | inode->i_ino = get_next_ino(); |
406 | ||
9043476f | 407 | sysctl_head_get(head); |
77b14db5 | 408 | ei = PROC_I(inode); |
9043476f AV |
409 | ei->sysctl = head; |
410 | ei->sysctl_entry = table; | |
411 | ||
77b14db5 | 412 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
9043476f | 413 | inode->i_mode = table->mode; |
7ec66d06 | 414 | if (!S_ISDIR(table->mode)) { |
9043476f AV |
415 | inode->i_mode |= S_IFREG; |
416 | inode->i_op = &proc_sys_inode_operations; | |
417 | inode->i_fop = &proc_sys_file_operations; | |
418 | } else { | |
419 | inode->i_mode |= S_IFDIR; | |
9043476f AV |
420 | inode->i_op = &proc_sys_dir_operations; |
421 | inode->i_fop = &proc_sys_dir_file_operations; | |
422 | } | |
77b14db5 EB |
423 | out: |
424 | return inode; | |
425 | } | |
426 | ||
81324364 | 427 | static struct ctl_table_header *grab_header(struct inode *inode) |
77b14db5 | 428 | { |
3cc3e046 EB |
429 | struct ctl_table_header *head = PROC_I(inode)->sysctl; |
430 | if (!head) | |
0e47c99d | 431 | head = &sysctl_table_root.default_set.dir.header; |
3cc3e046 | 432 | return sysctl_head_grab(head); |
9043476f | 433 | } |
77b14db5 | 434 | |
9043476f | 435 | static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, |
00cd8dd3 | 436 | unsigned int flags) |
9043476f AV |
437 | { |
438 | struct ctl_table_header *head = grab_header(dir); | |
9043476f AV |
439 | struct ctl_table_header *h = NULL; |
440 | struct qstr *name = &dentry->d_name; | |
441 | struct ctl_table *p; | |
442 | struct inode *inode; | |
443 | struct dentry *err = ERR_PTR(-ENOENT); | |
7ec66d06 | 444 | struct ctl_dir *ctl_dir; |
0e47c99d | 445 | int ret; |
77b14db5 | 446 | |
9043476f AV |
447 | if (IS_ERR(head)) |
448 | return ERR_CAST(head); | |
77b14db5 | 449 | |
7ec66d06 | 450 | ctl_dir = container_of(head, struct ctl_dir, header); |
77b14db5 | 451 | |
7ec66d06 | 452 | p = lookup_entry(&h, ctl_dir, name->name, name->len); |
9043476f | 453 | if (!p) |
77b14db5 EB |
454 | goto out; |
455 | ||
4e757320 EB |
456 | if (S_ISLNK(p->mode)) { |
457 | ret = sysctl_follow_link(&h, &p, current->nsproxy); | |
458 | err = ERR_PTR(ret); | |
459 | if (ret) | |
460 | goto out; | |
461 | } | |
0e47c99d | 462 | |
77b14db5 | 463 | err = ERR_PTR(-ENOMEM); |
9043476f | 464 | inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); |
77b14db5 EB |
465 | if (!inode) |
466 | goto out; | |
467 | ||
468 | err = NULL; | |
fb045adb | 469 | d_set_d_op(dentry, &proc_sys_dentry_operations); |
77b14db5 EB |
470 | d_add(dentry, inode); |
471 | ||
472 | out: | |
6bf61045 FR |
473 | if (h) |
474 | sysctl_head_finish(h); | |
77b14db5 EB |
475 | sysctl_head_finish(head); |
476 | return err; | |
477 | } | |
478 | ||
7708bfb1 PE |
479 | static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, |
480 | size_t count, loff_t *ppos, int write) | |
77b14db5 | 481 | { |
496ad9aa | 482 | struct inode *inode = file_inode(filp); |
9043476f AV |
483 | struct ctl_table_header *head = grab_header(inode); |
484 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
2a2da53b DH |
485 | ssize_t error; |
486 | size_t res; | |
77b14db5 | 487 | |
9043476f AV |
488 | if (IS_ERR(head)) |
489 | return PTR_ERR(head); | |
77b14db5 EB |
490 | |
491 | /* | |
492 | * At this point we know that the sysctl was not unregistered | |
493 | * and won't be until we finish. | |
494 | */ | |
495 | error = -EPERM; | |
73f7ef43 | 496 | if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) |
77b14db5 EB |
497 | goto out; |
498 | ||
9043476f AV |
499 | /* if that can happen at all, it should be -EINVAL, not -EISDIR */ |
500 | error = -EINVAL; | |
501 | if (!table->proc_handler) | |
502 | goto out; | |
503 | ||
77b14db5 EB |
504 | /* careful: calling conventions are nasty here */ |
505 | res = count; | |
8d65af78 | 506 | error = table->proc_handler(table, write, buf, &res, ppos); |
77b14db5 EB |
507 | if (!error) |
508 | error = res; | |
509 | out: | |
510 | sysctl_head_finish(head); | |
511 | ||
512 | return error; | |
513 | } | |
514 | ||
7708bfb1 | 515 | static ssize_t proc_sys_read(struct file *filp, char __user *buf, |
77b14db5 EB |
516 | size_t count, loff_t *ppos) |
517 | { | |
7708bfb1 PE |
518 | return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); |
519 | } | |
77b14db5 | 520 | |
7708bfb1 PE |
521 | static ssize_t proc_sys_write(struct file *filp, const char __user *buf, |
522 | size_t count, loff_t *ppos) | |
523 | { | |
524 | return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); | |
77b14db5 EB |
525 | } |
526 | ||
f1ecf068 LDM |
527 | static int proc_sys_open(struct inode *inode, struct file *filp) |
528 | { | |
4e474a00 | 529 | struct ctl_table_header *head = grab_header(inode); |
f1ecf068 LDM |
530 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
531 | ||
4e474a00 LDM |
532 | /* sysctl was unregistered */ |
533 | if (IS_ERR(head)) | |
534 | return PTR_ERR(head); | |
535 | ||
f1ecf068 LDM |
536 | if (table->poll) |
537 | filp->private_data = proc_sys_poll_event(table->poll); | |
538 | ||
4e474a00 LDM |
539 | sysctl_head_finish(head); |
540 | ||
f1ecf068 LDM |
541 | return 0; |
542 | } | |
543 | ||
544 | static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) | |
545 | { | |
496ad9aa | 546 | struct inode *inode = file_inode(filp); |
4e474a00 | 547 | struct ctl_table_header *head = grab_header(inode); |
f1ecf068 | 548 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
f1ecf068 | 549 | unsigned int ret = DEFAULT_POLLMASK; |
4e474a00 LDM |
550 | unsigned long event; |
551 | ||
552 | /* sysctl was unregistered */ | |
553 | if (IS_ERR(head)) | |
554 | return POLLERR | POLLHUP; | |
f1ecf068 LDM |
555 | |
556 | if (!table->proc_handler) | |
557 | goto out; | |
558 | ||
559 | if (!table->poll) | |
560 | goto out; | |
561 | ||
4e474a00 | 562 | event = (unsigned long)filp->private_data; |
f1ecf068 LDM |
563 | poll_wait(filp, &table->poll->wait, wait); |
564 | ||
565 | if (event != atomic_read(&table->poll->event)) { | |
566 | filp->private_data = proc_sys_poll_event(table->poll); | |
567 | ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; | |
568 | } | |
569 | ||
570 | out: | |
4e474a00 LDM |
571 | sysctl_head_finish(head); |
572 | ||
f1ecf068 LDM |
573 | return ret; |
574 | } | |
77b14db5 EB |
575 | |
576 | static int proc_sys_fill_cache(struct file *filp, void *dirent, | |
9043476f AV |
577 | filldir_t filldir, |
578 | struct ctl_table_header *head, | |
579 | struct ctl_table *table) | |
77b14db5 | 580 | { |
77b14db5 EB |
581 | struct dentry *child, *dir = filp->f_path.dentry; |
582 | struct inode *inode; | |
583 | struct qstr qname; | |
584 | ino_t ino = 0; | |
585 | unsigned type = DT_UNKNOWN; | |
77b14db5 EB |
586 | |
587 | qname.name = table->procname; | |
588 | qname.len = strlen(table->procname); | |
589 | qname.hash = full_name_hash(qname.name, qname.len); | |
590 | ||
77b14db5 EB |
591 | child = d_lookup(dir, &qname); |
592 | if (!child) { | |
9043476f AV |
593 | child = d_alloc(dir, &qname); |
594 | if (child) { | |
595 | inode = proc_sys_make_inode(dir->d_sb, head, table); | |
596 | if (!inode) { | |
597 | dput(child); | |
598 | return -ENOMEM; | |
599 | } else { | |
fb045adb | 600 | d_set_d_op(child, &proc_sys_dentry_operations); |
9043476f | 601 | d_add(child, inode); |
77b14db5 | 602 | } |
9043476f AV |
603 | } else { |
604 | return -ENOMEM; | |
77b14db5 EB |
605 | } |
606 | } | |
77b14db5 | 607 | inode = child->d_inode; |
9043476f AV |
608 | ino = inode->i_ino; |
609 | type = inode->i_mode >> 12; | |
77b14db5 | 610 | dput(child); |
9043476f AV |
611 | return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type); |
612 | } | |
613 | ||
0e47c99d EB |
614 | static int proc_sys_link_fill_cache(struct file *filp, void *dirent, |
615 | filldir_t filldir, | |
616 | struct ctl_table_header *head, | |
617 | struct ctl_table *table) | |
618 | { | |
619 | int err, ret = 0; | |
620 | head = sysctl_head_grab(head); | |
621 | ||
4e757320 EB |
622 | if (S_ISLNK(table->mode)) { |
623 | /* It is not an error if we can not follow the link ignore it */ | |
624 | err = sysctl_follow_link(&head, &table, current->nsproxy); | |
625 | if (err) | |
626 | goto out; | |
627 | } | |
0e47c99d EB |
628 | |
629 | ret = proc_sys_fill_cache(filp, dirent, filldir, head, table); | |
630 | out: | |
631 | sysctl_head_finish(head); | |
632 | return ret; | |
633 | } | |
634 | ||
9043476f AV |
635 | static int scan(struct ctl_table_header *head, ctl_table *table, |
636 | unsigned long *pos, struct file *file, | |
637 | void *dirent, filldir_t filldir) | |
638 | { | |
6a75ce16 | 639 | int res; |
9043476f | 640 | |
6a75ce16 EB |
641 | if ((*pos)++ < file->f_pos) |
642 | return 0; | |
9043476f | 643 | |
0e47c99d EB |
644 | if (unlikely(S_ISLNK(table->mode))) |
645 | res = proc_sys_link_fill_cache(file, dirent, filldir, head, table); | |
646 | else | |
9043476f | 647 | res = proc_sys_fill_cache(file, dirent, filldir, head, table); |
9043476f | 648 | |
6a75ce16 EB |
649 | if (res == 0) |
650 | file->f_pos = *pos; | |
9043476f | 651 | |
6a75ce16 | 652 | return res; |
77b14db5 EB |
653 | } |
654 | ||
655 | static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir) | |
656 | { | |
9043476f | 657 | struct dentry *dentry = filp->f_path.dentry; |
77b14db5 | 658 | struct inode *inode = dentry->d_inode; |
9043476f | 659 | struct ctl_table_header *head = grab_header(inode); |
9043476f | 660 | struct ctl_table_header *h = NULL; |
6a75ce16 | 661 | struct ctl_table *entry; |
7ec66d06 | 662 | struct ctl_dir *ctl_dir; |
77b14db5 | 663 | unsigned long pos; |
9043476f AV |
664 | int ret = -EINVAL; |
665 | ||
666 | if (IS_ERR(head)) | |
667 | return PTR_ERR(head); | |
77b14db5 | 668 | |
7ec66d06 | 669 | ctl_dir = container_of(head, struct ctl_dir, header); |
77b14db5 EB |
670 | |
671 | ret = 0; | |
672 | /* Avoid a switch here: arm builds fail with missing __cmpdi2 */ | |
673 | if (filp->f_pos == 0) { | |
674 | if (filldir(dirent, ".", 1, filp->f_pos, | |
675 | inode->i_ino, DT_DIR) < 0) | |
676 | goto out; | |
677 | filp->f_pos++; | |
678 | } | |
679 | if (filp->f_pos == 1) { | |
680 | if (filldir(dirent, "..", 2, filp->f_pos, | |
681 | parent_ino(dentry), DT_DIR) < 0) | |
682 | goto out; | |
683 | filp->f_pos++; | |
684 | } | |
685 | pos = 2; | |
686 | ||
7ec66d06 | 687 | for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { |
6a75ce16 | 688 | ret = scan(h, entry, &pos, filp, dirent, filldir); |
9043476f AV |
689 | if (ret) { |
690 | sysctl_head_finish(h); | |
691 | break; | |
77b14db5 EB |
692 | } |
693 | } | |
694 | ret = 1; | |
695 | out: | |
696 | sysctl_head_finish(head); | |
697 | return ret; | |
698 | } | |
699 | ||
10556cb2 | 700 | static int proc_sys_permission(struct inode *inode, int mask) |
77b14db5 EB |
701 | { |
702 | /* | |
703 | * sysctl entries that are not writeable, | |
704 | * are _NOT_ writeable, capabilities or not. | |
705 | */ | |
f696a365 MS |
706 | struct ctl_table_header *head; |
707 | struct ctl_table *table; | |
77b14db5 EB |
708 | int error; |
709 | ||
f696a365 MS |
710 | /* Executable files are not allowed under /proc/sys/ */ |
711 | if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) | |
712 | return -EACCES; | |
713 | ||
714 | head = grab_header(inode); | |
9043476f AV |
715 | if (IS_ERR(head)) |
716 | return PTR_ERR(head); | |
77b14db5 | 717 | |
f696a365 | 718 | table = PROC_I(inode)->sysctl_entry; |
9043476f AV |
719 | if (!table) /* global root - r-xr-xr-x */ |
720 | error = mask & MAY_WRITE ? -EACCES : 0; | |
721 | else /* Use the permissions on the sysctl table entry */ | |
73f7ef43 | 722 | error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); |
77b14db5 | 723 | |
77b14db5 EB |
724 | sysctl_head_finish(head); |
725 | return error; | |
726 | } | |
727 | ||
728 | static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) | |
729 | { | |
730 | struct inode *inode = dentry->d_inode; | |
731 | int error; | |
732 | ||
733 | if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) | |
734 | return -EPERM; | |
735 | ||
736 | error = inode_change_ok(inode, attr); | |
1025774c CH |
737 | if (error) |
738 | return error; | |
739 | ||
1025774c CH |
740 | setattr_copy(inode, attr); |
741 | mark_inode_dirty(inode); | |
742 | return 0; | |
77b14db5 EB |
743 | } |
744 | ||
9043476f AV |
745 | static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) |
746 | { | |
747 | struct inode *inode = dentry->d_inode; | |
748 | struct ctl_table_header *head = grab_header(inode); | |
749 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
750 | ||
751 | if (IS_ERR(head)) | |
752 | return PTR_ERR(head); | |
753 | ||
754 | generic_fillattr(inode, stat); | |
755 | if (table) | |
756 | stat->mode = (stat->mode & S_IFMT) | table->mode; | |
757 | ||
758 | sysctl_head_finish(head); | |
759 | return 0; | |
760 | } | |
761 | ||
77b14db5 | 762 | static const struct file_operations proc_sys_file_operations = { |
f1ecf068 LDM |
763 | .open = proc_sys_open, |
764 | .poll = proc_sys_poll, | |
77b14db5 EB |
765 | .read = proc_sys_read, |
766 | .write = proc_sys_write, | |
6038f373 | 767 | .llseek = default_llseek, |
9043476f AV |
768 | }; |
769 | ||
770 | static const struct file_operations proc_sys_dir_file_operations = { | |
887df078 | 771 | .read = generic_read_dir, |
77b14db5 | 772 | .readdir = proc_sys_readdir, |
3222a3e5 | 773 | .llseek = generic_file_llseek, |
77b14db5 EB |
774 | }; |
775 | ||
03a44825 | 776 | static const struct inode_operations proc_sys_inode_operations = { |
9043476f AV |
777 | .permission = proc_sys_permission, |
778 | .setattr = proc_sys_setattr, | |
779 | .getattr = proc_sys_getattr, | |
780 | }; | |
781 | ||
782 | static const struct inode_operations proc_sys_dir_operations = { | |
77b14db5 EB |
783 | .lookup = proc_sys_lookup, |
784 | .permission = proc_sys_permission, | |
785 | .setattr = proc_sys_setattr, | |
9043476f | 786 | .getattr = proc_sys_getattr, |
77b14db5 EB |
787 | }; |
788 | ||
0b728e19 | 789 | static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) |
77b14db5 | 790 | { |
0b728e19 | 791 | if (flags & LOOKUP_RCU) |
34286d66 | 792 | return -ECHILD; |
9043476f AV |
793 | return !PROC_I(dentry->d_inode)->sysctl->unregistering; |
794 | } | |
795 | ||
fe15ce44 | 796 | static int proc_sys_delete(const struct dentry *dentry) |
9043476f AV |
797 | { |
798 | return !!PROC_I(dentry->d_inode)->sysctl->unregistering; | |
799 | } | |
800 | ||
1f87f0b5 EB |
801 | static int sysctl_is_seen(struct ctl_table_header *p) |
802 | { | |
803 | struct ctl_table_set *set = p->set; | |
804 | int res; | |
805 | spin_lock(&sysctl_lock); | |
806 | if (p->unregistering) | |
807 | res = 0; | |
808 | else if (!set->is_seen) | |
809 | res = 1; | |
810 | else | |
811 | res = set->is_seen(set); | |
812 | spin_unlock(&sysctl_lock); | |
813 | return res; | |
814 | } | |
815 | ||
621e155a NP |
816 | static int proc_sys_compare(const struct dentry *parent, |
817 | const struct inode *pinode, | |
818 | const struct dentry *dentry, const struct inode *inode, | |
819 | unsigned int len, const char *str, const struct qstr *name) | |
9043476f | 820 | { |
dfef6dcd | 821 | struct ctl_table_header *head; |
31e6b01f NP |
822 | /* Although proc doesn't have negative dentries, rcu-walk means |
823 | * that inode here can be NULL */ | |
dfef6dcd | 824 | /* AV: can it, indeed? */ |
31e6b01f | 825 | if (!inode) |
dfef6dcd | 826 | return 1; |
621e155a | 827 | if (name->len != len) |
9043476f | 828 | return 1; |
621e155a | 829 | if (memcmp(name->name, str, len)) |
9043476f | 830 | return 1; |
dfef6dcd AV |
831 | head = rcu_dereference(PROC_I(inode)->sysctl); |
832 | return !head || !sysctl_is_seen(head); | |
77b14db5 EB |
833 | } |
834 | ||
d72f71eb | 835 | static const struct dentry_operations proc_sys_dentry_operations = { |
77b14db5 | 836 | .d_revalidate = proc_sys_revalidate, |
9043476f AV |
837 | .d_delete = proc_sys_delete, |
838 | .d_compare = proc_sys_compare, | |
77b14db5 EB |
839 | }; |
840 | ||
0e47c99d EB |
841 | static struct ctl_dir *find_subdir(struct ctl_dir *dir, |
842 | const char *name, int namelen) | |
1f87f0b5 | 843 | { |
7ec66d06 EB |
844 | struct ctl_table_header *head; |
845 | struct ctl_table *entry; | |
1f87f0b5 | 846 | |
0e47c99d | 847 | entry = find_entry(&head, dir, name, namelen); |
7ec66d06 EB |
848 | if (!entry) |
849 | return ERR_PTR(-ENOENT); | |
51f72f4a EB |
850 | if (!S_ISDIR(entry->mode)) |
851 | return ERR_PTR(-ENOTDIR); | |
852 | return container_of(head, struct ctl_dir, header); | |
7ec66d06 EB |
853 | } |
854 | ||
855 | static struct ctl_dir *new_dir(struct ctl_table_set *set, | |
0e47c99d | 856 | const char *name, int namelen) |
7ec66d06 EB |
857 | { |
858 | struct ctl_table *table; | |
859 | struct ctl_dir *new; | |
ac13ac6f | 860 | struct ctl_node *node; |
7ec66d06 | 861 | char *new_name; |
1f87f0b5 | 862 | |
ac13ac6f EB |
863 | new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + |
864 | sizeof(struct ctl_table)*2 + namelen + 1, | |
865 | GFP_KERNEL); | |
7ec66d06 | 866 | if (!new) |
1f87f0b5 EB |
867 | return NULL; |
868 | ||
ac13ac6f EB |
869 | node = (struct ctl_node *)(new + 1); |
870 | table = (struct ctl_table *)(node + 1); | |
7ec66d06 EB |
871 | new_name = (char *)(table + 2); |
872 | memcpy(new_name, name, namelen); | |
873 | new_name[namelen] = '\0'; | |
874 | table[0].procname = new_name; | |
875 | table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; | |
ac13ac6f | 876 | init_header(&new->header, set->dir.header.root, set, node, table); |
7ec66d06 EB |
877 | |
878 | return new; | |
1f87f0b5 EB |
879 | } |
880 | ||
60f126d9 EB |
881 | /** |
882 | * get_subdir - find or create a subdir with the specified name. | |
883 | * @dir: Directory to create the subdirectory in | |
884 | * @name: The name of the subdirectory to find or create | |
885 | * @namelen: The length of name | |
886 | * | |
887 | * Takes a directory with an elevated reference count so we know that | |
888 | * if we drop the lock the directory will not go away. Upon success | |
889 | * the reference is moved from @dir to the returned subdirectory. | |
890 | * Upon error an error code is returned and the reference on @dir is | |
891 | * simply dropped. | |
892 | */ | |
0e47c99d EB |
893 | static struct ctl_dir *get_subdir(struct ctl_dir *dir, |
894 | const char *name, int namelen) | |
1f87f0b5 | 895 | { |
0e47c99d | 896 | struct ctl_table_set *set = dir->header.set; |
7ec66d06 | 897 | struct ctl_dir *subdir, *new = NULL; |
0eb97f38 | 898 | int err; |
1f87f0b5 | 899 | |
7ec66d06 | 900 | spin_lock(&sysctl_lock); |
0e47c99d | 901 | subdir = find_subdir(dir, name, namelen); |
7ec66d06 EB |
902 | if (!IS_ERR(subdir)) |
903 | goto found; | |
904 | if (PTR_ERR(subdir) != -ENOENT) | |
905 | goto failed; | |
906 | ||
907 | spin_unlock(&sysctl_lock); | |
908 | new = new_dir(set, name, namelen); | |
909 | spin_lock(&sysctl_lock); | |
910 | subdir = ERR_PTR(-ENOMEM); | |
911 | if (!new) | |
912 | goto failed; | |
913 | ||
60f126d9 | 914 | /* Was the subdir added while we dropped the lock? */ |
0e47c99d | 915 | subdir = find_subdir(dir, name, namelen); |
7ec66d06 EB |
916 | if (!IS_ERR(subdir)) |
917 | goto found; | |
918 | if (PTR_ERR(subdir) != -ENOENT) | |
919 | goto failed; | |
920 | ||
60f126d9 | 921 | /* Nope. Use the our freshly made directory entry. */ |
0eb97f38 EB |
922 | err = insert_header(dir, &new->header); |
923 | subdir = ERR_PTR(err); | |
924 | if (err) | |
0e47c99d | 925 | goto failed; |
7ec66d06 EB |
926 | subdir = new; |
927 | found: | |
928 | subdir->header.nreg++; | |
929 | failed: | |
930 | if (unlikely(IS_ERR(subdir))) { | |
87ebdc00 | 931 | pr_err("sysctl could not get directory: "); |
6980128f | 932 | sysctl_print_dir(dir); |
87ebdc00 | 933 | pr_cont("/%*.*s %ld\n", |
7ec66d06 | 934 | namelen, namelen, name, PTR_ERR(subdir)); |
1f87f0b5 | 935 | } |
7ec66d06 EB |
936 | drop_sysctl_table(&dir->header); |
937 | if (new) | |
938 | drop_sysctl_table(&new->header); | |
939 | spin_unlock(&sysctl_lock); | |
940 | return subdir; | |
1f87f0b5 EB |
941 | } |
942 | ||
0e47c99d EB |
943 | static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) |
944 | { | |
945 | struct ctl_dir *parent; | |
946 | const char *procname; | |
947 | if (!dir->header.parent) | |
948 | return &set->dir; | |
949 | parent = xlate_dir(set, dir->header.parent); | |
950 | if (IS_ERR(parent)) | |
951 | return parent; | |
952 | procname = dir->header.ctl_table[0].procname; | |
953 | return find_subdir(parent, procname, strlen(procname)); | |
954 | } | |
955 | ||
956 | static int sysctl_follow_link(struct ctl_table_header **phead, | |
957 | struct ctl_table **pentry, struct nsproxy *namespaces) | |
958 | { | |
959 | struct ctl_table_header *head; | |
960 | struct ctl_table_root *root; | |
961 | struct ctl_table_set *set; | |
962 | struct ctl_table *entry; | |
963 | struct ctl_dir *dir; | |
964 | int ret; | |
965 | ||
0e47c99d EB |
966 | ret = 0; |
967 | spin_lock(&sysctl_lock); | |
968 | root = (*pentry)->data; | |
969 | set = lookup_header_set(root, namespaces); | |
970 | dir = xlate_dir(set, (*phead)->parent); | |
971 | if (IS_ERR(dir)) | |
972 | ret = PTR_ERR(dir); | |
973 | else { | |
974 | const char *procname = (*pentry)->procname; | |
975 | head = NULL; | |
976 | entry = find_entry(&head, dir, procname, strlen(procname)); | |
977 | ret = -ENOENT; | |
978 | if (entry && use_table(head)) { | |
979 | unuse_table(*phead); | |
980 | *phead = head; | |
981 | *pentry = entry; | |
982 | ret = 0; | |
983 | } | |
984 | } | |
985 | ||
986 | spin_unlock(&sysctl_lock); | |
987 | return ret; | |
988 | } | |
989 | ||
7c60c48f | 990 | static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) |
1f87f0b5 | 991 | { |
7c60c48f EB |
992 | struct va_format vaf; |
993 | va_list args; | |
1f87f0b5 | 994 | |
7c60c48f EB |
995 | va_start(args, fmt); |
996 | vaf.fmt = fmt; | |
997 | vaf.va = &args; | |
998 | ||
87ebdc00 AM |
999 | pr_err("sysctl table check failed: %s/%s %pV\n", |
1000 | path, table->procname, &vaf); | |
1f87f0b5 | 1001 | |
7c60c48f EB |
1002 | va_end(args); |
1003 | return -EINVAL; | |
1f87f0b5 EB |
1004 | } |
1005 | ||
7c60c48f | 1006 | static int sysctl_check_table(const char *path, struct ctl_table *table) |
1f87f0b5 | 1007 | { |
7c60c48f | 1008 | int err = 0; |
1f87f0b5 | 1009 | for (; table->procname; table++) { |
1f87f0b5 | 1010 | if (table->child) |
7c60c48f EB |
1011 | err = sysctl_err(path, table, "Not a file"); |
1012 | ||
1013 | if ((table->proc_handler == proc_dostring) || | |
1014 | (table->proc_handler == proc_dointvec) || | |
1015 | (table->proc_handler == proc_dointvec_minmax) || | |
1016 | (table->proc_handler == proc_dointvec_jiffies) || | |
1017 | (table->proc_handler == proc_dointvec_userhz_jiffies) || | |
1018 | (table->proc_handler == proc_dointvec_ms_jiffies) || | |
1019 | (table->proc_handler == proc_doulongvec_minmax) || | |
1020 | (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { | |
1021 | if (!table->data) | |
1022 | err = sysctl_err(path, table, "No data"); | |
1023 | if (!table->maxlen) | |
1024 | err = sysctl_err(path, table, "No maxlen"); | |
1025 | } | |
1026 | if (!table->proc_handler) | |
1027 | err = sysctl_err(path, table, "No proc_handler"); | |
1028 | ||
1029 | if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) | |
1030 | err = sysctl_err(path, table, "bogus .mode 0%o", | |
1031 | table->mode); | |
1f87f0b5 | 1032 | } |
7c60c48f | 1033 | return err; |
1f87f0b5 | 1034 | } |
1f87f0b5 | 1035 | |
0e47c99d EB |
1036 | static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, |
1037 | struct ctl_table_root *link_root) | |
1038 | { | |
1039 | struct ctl_table *link_table, *entry, *link; | |
1040 | struct ctl_table_header *links; | |
ac13ac6f | 1041 | struct ctl_node *node; |
0e47c99d EB |
1042 | char *link_name; |
1043 | int nr_entries, name_bytes; | |
1044 | ||
1045 | name_bytes = 0; | |
1046 | nr_entries = 0; | |
1047 | for (entry = table; entry->procname; entry++) { | |
1048 | nr_entries++; | |
1049 | name_bytes += strlen(entry->procname) + 1; | |
1050 | } | |
1051 | ||
1052 | links = kzalloc(sizeof(struct ctl_table_header) + | |
ac13ac6f | 1053 | sizeof(struct ctl_node)*nr_entries + |
0e47c99d EB |
1054 | sizeof(struct ctl_table)*(nr_entries + 1) + |
1055 | name_bytes, | |
1056 | GFP_KERNEL); | |
1057 | ||
1058 | if (!links) | |
1059 | return NULL; | |
1060 | ||
ac13ac6f EB |
1061 | node = (struct ctl_node *)(links + 1); |
1062 | link_table = (struct ctl_table *)(node + nr_entries); | |
0e47c99d EB |
1063 | link_name = (char *)&link_table[nr_entries + 1]; |
1064 | ||
1065 | for (link = link_table, entry = table; entry->procname; link++, entry++) { | |
1066 | int len = strlen(entry->procname) + 1; | |
1067 | memcpy(link_name, entry->procname, len); | |
1068 | link->procname = link_name; | |
1069 | link->mode = S_IFLNK|S_IRWXUGO; | |
1070 | link->data = link_root; | |
1071 | link_name += len; | |
1072 | } | |
ac13ac6f | 1073 | init_header(links, dir->header.root, dir->header.set, node, link_table); |
0e47c99d EB |
1074 | links->nreg = nr_entries; |
1075 | ||
1076 | return links; | |
1077 | } | |
1078 | ||
1079 | static bool get_links(struct ctl_dir *dir, | |
1080 | struct ctl_table *table, struct ctl_table_root *link_root) | |
1081 | { | |
1082 | struct ctl_table_header *head; | |
1083 | struct ctl_table *entry, *link; | |
1084 | ||
1085 | /* Are there links available for every entry in table? */ | |
1086 | for (entry = table; entry->procname; entry++) { | |
1087 | const char *procname = entry->procname; | |
1088 | link = find_entry(&head, dir, procname, strlen(procname)); | |
1089 | if (!link) | |
1090 | return false; | |
1091 | if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) | |
1092 | continue; | |
1093 | if (S_ISLNK(link->mode) && (link->data == link_root)) | |
1094 | continue; | |
1095 | return false; | |
1096 | } | |
1097 | ||
1098 | /* The checks passed. Increase the registration count on the links */ | |
1099 | for (entry = table; entry->procname; entry++) { | |
1100 | const char *procname = entry->procname; | |
1101 | link = find_entry(&head, dir, procname, strlen(procname)); | |
1102 | head->nreg++; | |
1103 | } | |
1104 | return true; | |
1105 | } | |
1106 | ||
1107 | static int insert_links(struct ctl_table_header *head) | |
1108 | { | |
1109 | struct ctl_table_set *root_set = &sysctl_table_root.default_set; | |
1110 | struct ctl_dir *core_parent = NULL; | |
1111 | struct ctl_table_header *links; | |
1112 | int err; | |
1113 | ||
1114 | if (head->set == root_set) | |
1115 | return 0; | |
1116 | ||
1117 | core_parent = xlate_dir(root_set, head->parent); | |
1118 | if (IS_ERR(core_parent)) | |
1119 | return 0; | |
1120 | ||
1121 | if (get_links(core_parent, head->ctl_table, head->root)) | |
1122 | return 0; | |
1123 | ||
1124 | core_parent->header.nreg++; | |
1125 | spin_unlock(&sysctl_lock); | |
1126 | ||
1127 | links = new_links(core_parent, head->ctl_table, head->root); | |
1128 | ||
1129 | spin_lock(&sysctl_lock); | |
1130 | err = -ENOMEM; | |
1131 | if (!links) | |
1132 | goto out; | |
1133 | ||
1134 | err = 0; | |
1135 | if (get_links(core_parent, head->ctl_table, head->root)) { | |
1136 | kfree(links); | |
1137 | goto out; | |
1138 | } | |
1139 | ||
1140 | err = insert_header(core_parent, links); | |
1141 | if (err) | |
1142 | kfree(links); | |
1143 | out: | |
1144 | drop_sysctl_table(&core_parent->header); | |
1145 | return err; | |
1146 | } | |
1147 | ||
1f87f0b5 | 1148 | /** |
f728019b | 1149 | * __register_sysctl_table - register a leaf sysctl table |
60a47a2e | 1150 | * @set: Sysctl tree to register on |
1f87f0b5 EB |
1151 | * @path: The path to the directory the sysctl table is in. |
1152 | * @table: the top-level table structure | |
1153 | * | |
1154 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1155 | * array. A completely 0 filled entry terminates the table. | |
1156 | * | |
1157 | * The members of the &struct ctl_table structure are used as follows: | |
1158 | * | |
1159 | * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not | |
1160 | * enter a sysctl file | |
1161 | * | |
1162 | * data - a pointer to data for use by proc_handler | |
1163 | * | |
1164 | * maxlen - the maximum size in bytes of the data | |
1165 | * | |
f728019b | 1166 | * mode - the file permissions for the /proc/sys file |
1f87f0b5 | 1167 | * |
f728019b | 1168 | * child - must be %NULL. |
1f87f0b5 EB |
1169 | * |
1170 | * proc_handler - the text handler routine (described below) | |
1171 | * | |
1f87f0b5 EB |
1172 | * extra1, extra2 - extra pointers usable by the proc handler routines |
1173 | * | |
1174 | * Leaf nodes in the sysctl tree will be represented by a single file | |
1175 | * under /proc; non-leaf nodes will be represented by directories. | |
1176 | * | |
f728019b EB |
1177 | * There must be a proc_handler routine for any terminal nodes. |
1178 | * Several default handlers are available to cover common cases - | |
1f87f0b5 EB |
1179 | * |
1180 | * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), | |
1181 | * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), | |
1182 | * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() | |
1183 | * | |
1184 | * It is the handler's job to read the input buffer from user memory | |
1185 | * and process it. The handler should return 0 on success. | |
1186 | * | |
1187 | * This routine returns %NULL on a failure to register, and a pointer | |
1188 | * to the table header on success. | |
1189 | */ | |
6e9d5164 | 1190 | struct ctl_table_header *__register_sysctl_table( |
60a47a2e | 1191 | struct ctl_table_set *set, |
6e9d5164 | 1192 | const char *path, struct ctl_table *table) |
1f87f0b5 | 1193 | { |
60a47a2e | 1194 | struct ctl_table_root *root = set->dir.header.root; |
1f87f0b5 | 1195 | struct ctl_table_header *header; |
6e9d5164 | 1196 | const char *name, *nextname; |
7ec66d06 | 1197 | struct ctl_dir *dir; |
ac13ac6f EB |
1198 | struct ctl_table *entry; |
1199 | struct ctl_node *node; | |
1200 | int nr_entries = 0; | |
1201 | ||
1202 | for (entry = table; entry->procname; entry++) | |
1203 | nr_entries++; | |
1f87f0b5 | 1204 | |
ac13ac6f EB |
1205 | header = kzalloc(sizeof(struct ctl_table_header) + |
1206 | sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); | |
1f87f0b5 EB |
1207 | if (!header) |
1208 | return NULL; | |
1209 | ||
ac13ac6f EB |
1210 | node = (struct ctl_node *)(header + 1); |
1211 | init_header(header, root, set, node, table); | |
7ec66d06 EB |
1212 | if (sysctl_check_table(path, table)) |
1213 | goto fail; | |
1214 | ||
1215 | spin_lock(&sysctl_lock); | |
0e47c99d | 1216 | dir = &set->dir; |
60f126d9 | 1217 | /* Reference moved down the diretory tree get_subdir */ |
7ec66d06 EB |
1218 | dir->header.nreg++; |
1219 | spin_unlock(&sysctl_lock); | |
1f87f0b5 | 1220 | |
7ec66d06 | 1221 | /* Find the directory for the ctl_table */ |
6e9d5164 EB |
1222 | for (name = path; name; name = nextname) { |
1223 | int namelen; | |
1224 | nextname = strchr(name, '/'); | |
1225 | if (nextname) { | |
1226 | namelen = nextname - name; | |
1227 | nextname++; | |
1228 | } else { | |
1229 | namelen = strlen(name); | |
1230 | } | |
1231 | if (namelen == 0) | |
1232 | continue; | |
1f87f0b5 | 1233 | |
0e47c99d | 1234 | dir = get_subdir(dir, name, namelen); |
7ec66d06 EB |
1235 | if (IS_ERR(dir)) |
1236 | goto fail; | |
1f87f0b5 | 1237 | } |
0e47c99d | 1238 | |
1f87f0b5 | 1239 | spin_lock(&sysctl_lock); |
0e47c99d | 1240 | if (insert_header(dir, header)) |
7ec66d06 | 1241 | goto fail_put_dir_locked; |
0e47c99d | 1242 | |
7ec66d06 | 1243 | drop_sysctl_table(&dir->header); |
1f87f0b5 EB |
1244 | spin_unlock(&sysctl_lock); |
1245 | ||
1246 | return header; | |
0e47c99d | 1247 | |
7ec66d06 EB |
1248 | fail_put_dir_locked: |
1249 | drop_sysctl_table(&dir->header); | |
7c60c48f EB |
1250 | spin_unlock(&sysctl_lock); |
1251 | fail: | |
1252 | kfree(header); | |
1253 | dump_stack(); | |
1254 | return NULL; | |
1f87f0b5 EB |
1255 | } |
1256 | ||
fea478d4 EB |
1257 | /** |
1258 | * register_sysctl - register a sysctl table | |
1259 | * @path: The path to the directory the sysctl table is in. | |
1260 | * @table: the table structure | |
1261 | * | |
1262 | * Register a sysctl table. @table should be a filled in ctl_table | |
1263 | * array. A completely 0 filled entry terminates the table. | |
1264 | * | |
1265 | * See __register_sysctl_table for more details. | |
1266 | */ | |
1267 | struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) | |
1268 | { | |
1269 | return __register_sysctl_table(&sysctl_table_root.default_set, | |
1270 | path, table); | |
1271 | } | |
1272 | EXPORT_SYMBOL(register_sysctl); | |
1273 | ||
6e9d5164 EB |
1274 | static char *append_path(const char *path, char *pos, const char *name) |
1275 | { | |
1276 | int namelen; | |
1277 | namelen = strlen(name); | |
1278 | if (((pos - path) + namelen + 2) >= PATH_MAX) | |
1279 | return NULL; | |
1280 | memcpy(pos, name, namelen); | |
1281 | pos[namelen] = '/'; | |
1282 | pos[namelen + 1] = '\0'; | |
1283 | pos += namelen + 1; | |
1284 | return pos; | |
1285 | } | |
1286 | ||
f728019b EB |
1287 | static int count_subheaders(struct ctl_table *table) |
1288 | { | |
1289 | int has_files = 0; | |
1290 | int nr_subheaders = 0; | |
1291 | struct ctl_table *entry; | |
1292 | ||
1293 | /* special case: no directory and empty directory */ | |
1294 | if (!table || !table->procname) | |
1295 | return 1; | |
1296 | ||
1297 | for (entry = table; entry->procname; entry++) { | |
1298 | if (entry->child) | |
1299 | nr_subheaders += count_subheaders(entry->child); | |
1300 | else | |
1301 | has_files = 1; | |
1302 | } | |
1303 | return nr_subheaders + has_files; | |
1304 | } | |
1305 | ||
1306 | static int register_leaf_sysctl_tables(const char *path, char *pos, | |
60a47a2e | 1307 | struct ctl_table_header ***subheader, struct ctl_table_set *set, |
f728019b EB |
1308 | struct ctl_table *table) |
1309 | { | |
1310 | struct ctl_table *ctl_table_arg = NULL; | |
1311 | struct ctl_table *entry, *files; | |
1312 | int nr_files = 0; | |
1313 | int nr_dirs = 0; | |
1314 | int err = -ENOMEM; | |
1315 | ||
1316 | for (entry = table; entry->procname; entry++) { | |
1317 | if (entry->child) | |
1318 | nr_dirs++; | |
1319 | else | |
1320 | nr_files++; | |
1321 | } | |
1322 | ||
1323 | files = table; | |
1324 | /* If there are mixed files and directories we need a new table */ | |
1325 | if (nr_dirs && nr_files) { | |
1326 | struct ctl_table *new; | |
1327 | files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), | |
1328 | GFP_KERNEL); | |
1329 | if (!files) | |
1330 | goto out; | |
1331 | ||
1332 | ctl_table_arg = files; | |
1333 | for (new = files, entry = table; entry->procname; entry++) { | |
1334 | if (entry->child) | |
1335 | continue; | |
1336 | *new = *entry; | |
1337 | new++; | |
1338 | } | |
1339 | } | |
1340 | ||
1341 | /* Register everything except a directory full of subdirectories */ | |
1342 | if (nr_files || !nr_dirs) { | |
1343 | struct ctl_table_header *header; | |
60a47a2e | 1344 | header = __register_sysctl_table(set, path, files); |
f728019b EB |
1345 | if (!header) { |
1346 | kfree(ctl_table_arg); | |
1347 | goto out; | |
1348 | } | |
1349 | ||
1350 | /* Remember if we need to free the file table */ | |
1351 | header->ctl_table_arg = ctl_table_arg; | |
1352 | **subheader = header; | |
1353 | (*subheader)++; | |
1354 | } | |
1355 | ||
1356 | /* Recurse into the subdirectories. */ | |
1357 | for (entry = table; entry->procname; entry++) { | |
1358 | char *child_pos; | |
1359 | ||
1360 | if (!entry->child) | |
1361 | continue; | |
1362 | ||
1363 | err = -ENAMETOOLONG; | |
1364 | child_pos = append_path(path, pos, entry->procname); | |
1365 | if (!child_pos) | |
1366 | goto out; | |
1367 | ||
1368 | err = register_leaf_sysctl_tables(path, child_pos, subheader, | |
60a47a2e | 1369 | set, entry->child); |
f728019b EB |
1370 | pos[0] = '\0'; |
1371 | if (err) | |
1372 | goto out; | |
1373 | } | |
1374 | err = 0; | |
1375 | out: | |
1376 | /* On failure our caller will unregister all registered subheaders */ | |
1377 | return err; | |
1378 | } | |
1379 | ||
6e9d5164 EB |
1380 | /** |
1381 | * __register_sysctl_paths - register a sysctl table hierarchy | |
60a47a2e | 1382 | * @set: Sysctl tree to register on |
6e9d5164 EB |
1383 | * @path: The path to the directory the sysctl table is in. |
1384 | * @table: the top-level table structure | |
1385 | * | |
1386 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1387 | * array. A completely 0 filled entry terminates the table. | |
1388 | * | |
1389 | * See __register_sysctl_table for more details. | |
1390 | */ | |
1391 | struct ctl_table_header *__register_sysctl_paths( | |
60a47a2e | 1392 | struct ctl_table_set *set, |
6e9d5164 EB |
1393 | const struct ctl_path *path, struct ctl_table *table) |
1394 | { | |
ec6a5266 | 1395 | struct ctl_table *ctl_table_arg = table; |
f728019b EB |
1396 | int nr_subheaders = count_subheaders(table); |
1397 | struct ctl_table_header *header = NULL, **subheaders, **subheader; | |
6e9d5164 EB |
1398 | const struct ctl_path *component; |
1399 | char *new_path, *pos; | |
1400 | ||
1401 | pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); | |
1402 | if (!new_path) | |
1403 | return NULL; | |
1404 | ||
1405 | pos[0] = '\0'; | |
1406 | for (component = path; component->procname; component++) { | |
1407 | pos = append_path(new_path, pos, component->procname); | |
1408 | if (!pos) | |
1409 | goto out; | |
1410 | } | |
ec6a5266 EB |
1411 | while (table->procname && table->child && !table[1].procname) { |
1412 | pos = append_path(new_path, pos, table->procname); | |
1413 | if (!pos) | |
1414 | goto out; | |
1415 | table = table->child; | |
1416 | } | |
f728019b | 1417 | if (nr_subheaders == 1) { |
60a47a2e | 1418 | header = __register_sysctl_table(set, new_path, table); |
f728019b EB |
1419 | if (header) |
1420 | header->ctl_table_arg = ctl_table_arg; | |
1421 | } else { | |
1422 | header = kzalloc(sizeof(*header) + | |
1423 | sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); | |
1424 | if (!header) | |
1425 | goto out; | |
1426 | ||
1427 | subheaders = (struct ctl_table_header **) (header + 1); | |
1428 | subheader = subheaders; | |
ec6a5266 | 1429 | header->ctl_table_arg = ctl_table_arg; |
f728019b EB |
1430 | |
1431 | if (register_leaf_sysctl_tables(new_path, pos, &subheader, | |
60a47a2e | 1432 | set, table)) |
f728019b EB |
1433 | goto err_register_leaves; |
1434 | } | |
1435 | ||
6e9d5164 EB |
1436 | out: |
1437 | kfree(new_path); | |
1438 | return header; | |
f728019b EB |
1439 | |
1440 | err_register_leaves: | |
1441 | while (subheader > subheaders) { | |
1442 | struct ctl_table_header *subh = *(--subheader); | |
1443 | struct ctl_table *table = subh->ctl_table_arg; | |
1444 | unregister_sysctl_table(subh); | |
1445 | kfree(table); | |
1446 | } | |
1447 | kfree(header); | |
1448 | header = NULL; | |
1449 | goto out; | |
6e9d5164 EB |
1450 | } |
1451 | ||
1f87f0b5 EB |
1452 | /** |
1453 | * register_sysctl_table_path - register a sysctl table hierarchy | |
1454 | * @path: The path to the directory the sysctl table is in. | |
1455 | * @table: the top-level table structure | |
1456 | * | |
1457 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1458 | * array. A completely 0 filled entry terminates the table. | |
1459 | * | |
1460 | * See __register_sysctl_paths for more details. | |
1461 | */ | |
1462 | struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, | |
1463 | struct ctl_table *table) | |
1464 | { | |
60a47a2e | 1465 | return __register_sysctl_paths(&sysctl_table_root.default_set, |
1f87f0b5 EB |
1466 | path, table); |
1467 | } | |
1468 | EXPORT_SYMBOL(register_sysctl_paths); | |
1469 | ||
1470 | /** | |
1471 | * register_sysctl_table - register a sysctl table hierarchy | |
1472 | * @table: the top-level table structure | |
1473 | * | |
1474 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1475 | * array. A completely 0 filled entry terminates the table. | |
1476 | * | |
1477 | * See register_sysctl_paths for more details. | |
1478 | */ | |
1479 | struct ctl_table_header *register_sysctl_table(struct ctl_table *table) | |
1480 | { | |
1481 | static const struct ctl_path null_path[] = { {} }; | |
1482 | ||
1483 | return register_sysctl_paths(null_path, table); | |
1484 | } | |
1485 | EXPORT_SYMBOL(register_sysctl_table); | |
1486 | ||
0e47c99d EB |
1487 | static void put_links(struct ctl_table_header *header) |
1488 | { | |
1489 | struct ctl_table_set *root_set = &sysctl_table_root.default_set; | |
1490 | struct ctl_table_root *root = header->root; | |
1491 | struct ctl_dir *parent = header->parent; | |
1492 | struct ctl_dir *core_parent; | |
1493 | struct ctl_table *entry; | |
1494 | ||
1495 | if (header->set == root_set) | |
1496 | return; | |
1497 | ||
1498 | core_parent = xlate_dir(root_set, parent); | |
1499 | if (IS_ERR(core_parent)) | |
1500 | return; | |
1501 | ||
1502 | for (entry = header->ctl_table; entry->procname; entry++) { | |
1503 | struct ctl_table_header *link_head; | |
1504 | struct ctl_table *link; | |
1505 | const char *name = entry->procname; | |
1506 | ||
1507 | link = find_entry(&link_head, core_parent, name, strlen(name)); | |
1508 | if (link && | |
1509 | ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || | |
1510 | (S_ISLNK(link->mode) && (link->data == root)))) { | |
1511 | drop_sysctl_table(link_head); | |
1512 | } | |
1513 | else { | |
87ebdc00 | 1514 | pr_err("sysctl link missing during unregister: "); |
0e47c99d | 1515 | sysctl_print_dir(parent); |
87ebdc00 | 1516 | pr_cont("/%s\n", name); |
0e47c99d EB |
1517 | } |
1518 | } | |
1519 | } | |
1520 | ||
938aaa4f EB |
1521 | static void drop_sysctl_table(struct ctl_table_header *header) |
1522 | { | |
7ec66d06 EB |
1523 | struct ctl_dir *parent = header->parent; |
1524 | ||
938aaa4f EB |
1525 | if (--header->nreg) |
1526 | return; | |
1527 | ||
0e47c99d | 1528 | put_links(header); |
938aaa4f | 1529 | start_unregistering(header); |
938aaa4f EB |
1530 | if (!--header->count) |
1531 | kfree_rcu(header, rcu); | |
7ec66d06 EB |
1532 | |
1533 | if (parent) | |
1534 | drop_sysctl_table(&parent->header); | |
938aaa4f EB |
1535 | } |
1536 | ||
1f87f0b5 EB |
1537 | /** |
1538 | * unregister_sysctl_table - unregister a sysctl table hierarchy | |
1539 | * @header: the header returned from register_sysctl_table | |
1540 | * | |
1541 | * Unregisters the sysctl table and all children. proc entries may not | |
1542 | * actually be removed until they are no longer used by anyone. | |
1543 | */ | |
1544 | void unregister_sysctl_table(struct ctl_table_header * header) | |
1545 | { | |
f728019b | 1546 | int nr_subheaders; |
1f87f0b5 EB |
1547 | might_sleep(); |
1548 | ||
1549 | if (header == NULL) | |
1550 | return; | |
1551 | ||
f728019b EB |
1552 | nr_subheaders = count_subheaders(header->ctl_table_arg); |
1553 | if (unlikely(nr_subheaders > 1)) { | |
1554 | struct ctl_table_header **subheaders; | |
1555 | int i; | |
1556 | ||
1557 | subheaders = (struct ctl_table_header **)(header + 1); | |
1558 | for (i = nr_subheaders -1; i >= 0; i--) { | |
1559 | struct ctl_table_header *subh = subheaders[i]; | |
1560 | struct ctl_table *table = subh->ctl_table_arg; | |
1561 | unregister_sysctl_table(subh); | |
1562 | kfree(table); | |
1563 | } | |
1564 | kfree(header); | |
1565 | return; | |
1566 | } | |
1567 | ||
1f87f0b5 | 1568 | spin_lock(&sysctl_lock); |
938aaa4f | 1569 | drop_sysctl_table(header); |
1f87f0b5 EB |
1570 | spin_unlock(&sysctl_lock); |
1571 | } | |
1572 | EXPORT_SYMBOL(unregister_sysctl_table); | |
1573 | ||
0e47c99d | 1574 | void setup_sysctl_set(struct ctl_table_set *set, |
9eb47c26 | 1575 | struct ctl_table_root *root, |
1f87f0b5 EB |
1576 | int (*is_seen)(struct ctl_table_set *)) |
1577 | { | |
1347440d | 1578 | memset(set, 0, sizeof(*set)); |
0e47c99d | 1579 | set->is_seen = is_seen; |
ac13ac6f | 1580 | init_header(&set->dir.header, root, set, NULL, root_table); |
1f87f0b5 EB |
1581 | } |
1582 | ||
97324cd8 EB |
1583 | void retire_sysctl_set(struct ctl_table_set *set) |
1584 | { | |
ac13ac6f | 1585 | WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); |
97324cd8 | 1586 | } |
1f87f0b5 | 1587 | |
1e0edd3f | 1588 | int __init proc_sys_init(void) |
77b14db5 | 1589 | { |
e1675231 AD |
1590 | struct proc_dir_entry *proc_sys_root; |
1591 | ||
77b14db5 | 1592 | proc_sys_root = proc_mkdir("sys", NULL); |
9043476f AV |
1593 | proc_sys_root->proc_iops = &proc_sys_dir_operations; |
1594 | proc_sys_root->proc_fops = &proc_sys_dir_file_operations; | |
77b14db5 | 1595 | proc_sys_root->nlink = 0; |
de4e83bd EB |
1596 | |
1597 | return sysctl_init(); | |
77b14db5 | 1598 | } |