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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 EB |
7 | #include <linux/proc_fs.h> |
8 | #include <linux/security.h> | |
34286d66 | 9 | #include <linux/namei.h> |
1f87f0b5 | 10 | #include <linux/module.h> |
77b14db5 EB |
11 | #include "internal.h" |
12 | ||
d72f71eb | 13 | static const struct dentry_operations proc_sys_dentry_operations; |
77b14db5 | 14 | static const struct file_operations proc_sys_file_operations; |
03a44825 | 15 | static const struct inode_operations proc_sys_inode_operations; |
9043476f AV |
16 | static const struct file_operations proc_sys_dir_file_operations; |
17 | static const struct inode_operations proc_sys_dir_operations; | |
77b14db5 | 18 | |
f1ecf068 LDM |
19 | void proc_sys_poll_notify(struct ctl_table_poll *poll) |
20 | { | |
21 | if (!poll) | |
22 | return; | |
23 | ||
24 | atomic_inc(&poll->event); | |
25 | wake_up_interruptible(&poll->wait); | |
26 | } | |
27 | ||
1f87f0b5 EB |
28 | static struct ctl_table root_table[1]; |
29 | static struct ctl_table_root sysctl_table_root; | |
30 | static struct ctl_table_header root_table_header = { | |
31 | {{.count = 1, | |
938aaa4f EB |
32 | .nreg = 1, |
33 | .ctl_table = root_table, | |
34 | .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}}, | |
1f87f0b5 EB |
35 | .root = &sysctl_table_root, |
36 | .set = &sysctl_table_root.default_set, | |
37 | }; | |
38 | static struct ctl_table_root sysctl_table_root = { | |
39 | .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list), | |
40 | .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry), | |
41 | }; | |
42 | ||
43 | static DEFINE_SPINLOCK(sysctl_lock); | |
44 | ||
e0d04529 EB |
45 | static void init_header(struct ctl_table_header *head, |
46 | struct ctl_table_root *root, struct ctl_table_set *set, | |
47 | struct ctl_table *table) | |
48 | { | |
49 | head->ctl_table_arg = table; | |
50 | INIT_LIST_HEAD(&head->ctl_entry); | |
51 | head->used = 0; | |
52 | head->count = 1; | |
53 | head->nreg = 1; | |
54 | head->unregistering = NULL; | |
55 | head->root = root; | |
56 | head->set = set; | |
57 | head->parent = NULL; | |
58 | } | |
59 | ||
8425d6aa EB |
60 | static void erase_header(struct ctl_table_header *head) |
61 | { | |
62 | list_del_init(&head->ctl_entry); | |
63 | } | |
64 | ||
65 | static void insert_header(struct ctl_table_header *header) | |
66 | { | |
67 | header->parent->count++; | |
68 | list_add_tail(&header->ctl_entry, &header->set->list); | |
69 | } | |
70 | ||
1f87f0b5 EB |
71 | /* called under sysctl_lock */ |
72 | static int use_table(struct ctl_table_header *p) | |
73 | { | |
74 | if (unlikely(p->unregistering)) | |
75 | return 0; | |
76 | p->used++; | |
77 | return 1; | |
78 | } | |
79 | ||
80 | /* called under sysctl_lock */ | |
81 | static void unuse_table(struct ctl_table_header *p) | |
82 | { | |
83 | if (!--p->used) | |
84 | if (unlikely(p->unregistering)) | |
85 | complete(p->unregistering); | |
86 | } | |
87 | ||
88 | /* called under sysctl_lock, will reacquire if has to wait */ | |
89 | static void start_unregistering(struct ctl_table_header *p) | |
90 | { | |
91 | /* | |
92 | * if p->used is 0, nobody will ever touch that entry again; | |
93 | * we'll eliminate all paths to it before dropping sysctl_lock | |
94 | */ | |
95 | if (unlikely(p->used)) { | |
96 | struct completion wait; | |
97 | init_completion(&wait); | |
98 | p->unregistering = &wait; | |
99 | spin_unlock(&sysctl_lock); | |
100 | wait_for_completion(&wait); | |
101 | spin_lock(&sysctl_lock); | |
102 | } else { | |
103 | /* anything non-NULL; we'll never dereference it */ | |
104 | p->unregistering = ERR_PTR(-EINVAL); | |
105 | } | |
106 | /* | |
107 | * do not remove from the list until nobody holds it; walking the | |
108 | * list in do_sysctl() relies on that. | |
109 | */ | |
8425d6aa | 110 | erase_header(p); |
1f87f0b5 EB |
111 | } |
112 | ||
113 | static void sysctl_head_get(struct ctl_table_header *head) | |
114 | { | |
115 | spin_lock(&sysctl_lock); | |
116 | head->count++; | |
117 | spin_unlock(&sysctl_lock); | |
118 | } | |
119 | ||
120 | void sysctl_head_put(struct ctl_table_header *head) | |
121 | { | |
122 | spin_lock(&sysctl_lock); | |
123 | if (!--head->count) | |
124 | kfree_rcu(head, rcu); | |
125 | spin_unlock(&sysctl_lock); | |
126 | } | |
127 | ||
128 | static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) | |
129 | { | |
130 | if (!head) | |
131 | BUG(); | |
132 | spin_lock(&sysctl_lock); | |
133 | if (!use_table(head)) | |
134 | head = ERR_PTR(-ENOENT); | |
135 | spin_unlock(&sysctl_lock); | |
136 | return head; | |
137 | } | |
138 | ||
139 | static void sysctl_head_finish(struct ctl_table_header *head) | |
140 | { | |
141 | if (!head) | |
142 | return; | |
143 | spin_lock(&sysctl_lock); | |
144 | unuse_table(head); | |
145 | spin_unlock(&sysctl_lock); | |
146 | } | |
147 | ||
148 | static struct ctl_table_set * | |
149 | lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces) | |
150 | { | |
151 | struct ctl_table_set *set = &root->default_set; | |
152 | if (root->lookup) | |
153 | set = root->lookup(root, namespaces); | |
154 | return set; | |
155 | } | |
156 | ||
157 | static struct list_head * | |
158 | lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces) | |
159 | { | |
160 | struct ctl_table_set *set = lookup_header_set(root, namespaces); | |
161 | return &set->list; | |
162 | } | |
163 | ||
164 | static struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces, | |
165 | struct ctl_table_header *prev) | |
166 | { | |
167 | struct ctl_table_root *root; | |
168 | struct list_head *header_list; | |
169 | struct ctl_table_header *head; | |
170 | struct list_head *tmp; | |
171 | ||
172 | spin_lock(&sysctl_lock); | |
173 | if (prev) { | |
174 | head = prev; | |
175 | tmp = &prev->ctl_entry; | |
176 | unuse_table(prev); | |
177 | goto next; | |
178 | } | |
179 | tmp = &root_table_header.ctl_entry; | |
180 | for (;;) { | |
181 | head = list_entry(tmp, struct ctl_table_header, ctl_entry); | |
182 | ||
183 | if (!use_table(head)) | |
184 | goto next; | |
185 | spin_unlock(&sysctl_lock); | |
186 | return head; | |
187 | next: | |
188 | root = head->root; | |
189 | tmp = tmp->next; | |
190 | header_list = lookup_header_list(root, namespaces); | |
191 | if (tmp != header_list) | |
192 | continue; | |
193 | ||
194 | do { | |
195 | root = list_entry(root->root_list.next, | |
196 | struct ctl_table_root, root_list); | |
197 | if (root == &sysctl_table_root) | |
198 | goto out; | |
199 | header_list = lookup_header_list(root, namespaces); | |
200 | } while (list_empty(header_list)); | |
201 | tmp = header_list->next; | |
202 | } | |
203 | out: | |
204 | spin_unlock(&sysctl_lock); | |
205 | return NULL; | |
206 | } | |
207 | ||
208 | static struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev) | |
209 | { | |
210 | return __sysctl_head_next(current->nsproxy, prev); | |
211 | } | |
212 | ||
213 | void register_sysctl_root(struct ctl_table_root *root) | |
214 | { | |
215 | spin_lock(&sysctl_lock); | |
216 | list_add_tail(&root->root_list, &sysctl_table_root.root_list); | |
217 | spin_unlock(&sysctl_lock); | |
218 | } | |
219 | ||
220 | /* | |
221 | * sysctl_perm does NOT grant the superuser all rights automatically, because | |
222 | * some sysctl variables are readonly even to root. | |
223 | */ | |
224 | ||
225 | static int test_perm(int mode, int op) | |
226 | { | |
227 | if (!current_euid()) | |
228 | mode >>= 6; | |
229 | else if (in_egroup_p(0)) | |
230 | mode >>= 3; | |
231 | if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) | |
232 | return 0; | |
233 | return -EACCES; | |
234 | } | |
235 | ||
236 | static int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op) | |
237 | { | |
238 | int mode; | |
239 | ||
240 | if (root->permissions) | |
241 | mode = root->permissions(root, current->nsproxy, table); | |
242 | else | |
243 | mode = table->mode; | |
244 | ||
245 | return test_perm(mode, op); | |
246 | } | |
247 | ||
9043476f AV |
248 | static struct inode *proc_sys_make_inode(struct super_block *sb, |
249 | struct ctl_table_header *head, struct ctl_table *table) | |
77b14db5 EB |
250 | { |
251 | struct inode *inode; | |
9043476f | 252 | struct proc_inode *ei; |
77b14db5 | 253 | |
9043476f | 254 | inode = new_inode(sb); |
77b14db5 EB |
255 | if (!inode) |
256 | goto out; | |
257 | ||
85fe4025 CH |
258 | inode->i_ino = get_next_ino(); |
259 | ||
9043476f | 260 | sysctl_head_get(head); |
77b14db5 | 261 | ei = PROC_I(inode); |
9043476f AV |
262 | ei->sysctl = head; |
263 | ei->sysctl_entry = table; | |
264 | ||
77b14db5 | 265 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
9043476f AV |
266 | inode->i_mode = table->mode; |
267 | if (!table->child) { | |
268 | inode->i_mode |= S_IFREG; | |
269 | inode->i_op = &proc_sys_inode_operations; | |
270 | inode->i_fop = &proc_sys_file_operations; | |
271 | } else { | |
272 | inode->i_mode |= S_IFDIR; | |
9043476f AV |
273 | inode->i_op = &proc_sys_dir_operations; |
274 | inode->i_fop = &proc_sys_dir_file_operations; | |
275 | } | |
77b14db5 EB |
276 | out: |
277 | return inode; | |
278 | } | |
279 | ||
9043476f | 280 | static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name) |
77b14db5 | 281 | { |
2315ffa0 | 282 | for ( ; p->procname; p++) { |
36885d7b | 283 | if (strlen(p->procname) != name->len) |
77b14db5 EB |
284 | continue; |
285 | ||
36885d7b | 286 | if (memcmp(p->procname, name->name, name->len) != 0) |
77b14db5 EB |
287 | continue; |
288 | ||
289 | /* I have a match */ | |
9043476f | 290 | return p; |
77b14db5 EB |
291 | } |
292 | return NULL; | |
293 | } | |
294 | ||
81324364 | 295 | static struct ctl_table_header *grab_header(struct inode *inode) |
77b14db5 | 296 | { |
3cc3e046 EB |
297 | struct ctl_table_header *head = PROC_I(inode)->sysctl; |
298 | if (!head) | |
299 | head = &root_table_header; | |
300 | return sysctl_head_grab(head); | |
9043476f | 301 | } |
77b14db5 | 302 | |
9043476f AV |
303 | static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, |
304 | struct nameidata *nd) | |
305 | { | |
306 | struct ctl_table_header *head = grab_header(dir); | |
307 | struct ctl_table *table = PROC_I(dir)->sysctl_entry; | |
308 | struct ctl_table_header *h = NULL; | |
309 | struct qstr *name = &dentry->d_name; | |
310 | struct ctl_table *p; | |
311 | struct inode *inode; | |
312 | struct dentry *err = ERR_PTR(-ENOENT); | |
77b14db5 | 313 | |
9043476f AV |
314 | if (IS_ERR(head)) |
315 | return ERR_CAST(head); | |
77b14db5 | 316 | |
9043476f AV |
317 | if (table && !table->child) { |
318 | WARN_ON(1); | |
319 | goto out; | |
77b14db5 | 320 | } |
77b14db5 | 321 | |
9043476f | 322 | table = table ? table->child : head->ctl_table; |
77b14db5 | 323 | |
9043476f AV |
324 | p = find_in_table(table, name); |
325 | if (!p) { | |
326 | for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { | |
327 | if (h->attached_to != table) | |
328 | continue; | |
329 | p = find_in_table(h->attached_by, name); | |
330 | if (p) | |
331 | break; | |
332 | } | |
77b14db5 | 333 | } |
77b14db5 | 334 | |
9043476f | 335 | if (!p) |
77b14db5 EB |
336 | goto out; |
337 | ||
338 | err = ERR_PTR(-ENOMEM); | |
9043476f AV |
339 | inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); |
340 | if (h) | |
341 | sysctl_head_finish(h); | |
342 | ||
77b14db5 EB |
343 | if (!inode) |
344 | goto out; | |
345 | ||
346 | err = NULL; | |
fb045adb | 347 | d_set_d_op(dentry, &proc_sys_dentry_operations); |
77b14db5 EB |
348 | d_add(dentry, inode); |
349 | ||
350 | out: | |
351 | sysctl_head_finish(head); | |
352 | return err; | |
353 | } | |
354 | ||
7708bfb1 PE |
355 | static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, |
356 | size_t count, loff_t *ppos, int write) | |
77b14db5 | 357 | { |
9043476f AV |
358 | struct inode *inode = filp->f_path.dentry->d_inode; |
359 | struct ctl_table_header *head = grab_header(inode); | |
360 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
2a2da53b DH |
361 | ssize_t error; |
362 | size_t res; | |
77b14db5 | 363 | |
9043476f AV |
364 | if (IS_ERR(head)) |
365 | return PTR_ERR(head); | |
77b14db5 EB |
366 | |
367 | /* | |
368 | * At this point we know that the sysctl was not unregistered | |
369 | * and won't be until we finish. | |
370 | */ | |
371 | error = -EPERM; | |
d7321cd6 | 372 | if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ)) |
77b14db5 EB |
373 | goto out; |
374 | ||
9043476f AV |
375 | /* if that can happen at all, it should be -EINVAL, not -EISDIR */ |
376 | error = -EINVAL; | |
377 | if (!table->proc_handler) | |
378 | goto out; | |
379 | ||
77b14db5 EB |
380 | /* careful: calling conventions are nasty here */ |
381 | res = count; | |
8d65af78 | 382 | error = table->proc_handler(table, write, buf, &res, ppos); |
77b14db5 EB |
383 | if (!error) |
384 | error = res; | |
385 | out: | |
386 | sysctl_head_finish(head); | |
387 | ||
388 | return error; | |
389 | } | |
390 | ||
7708bfb1 | 391 | static ssize_t proc_sys_read(struct file *filp, char __user *buf, |
77b14db5 EB |
392 | size_t count, loff_t *ppos) |
393 | { | |
7708bfb1 PE |
394 | return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); |
395 | } | |
77b14db5 | 396 | |
7708bfb1 PE |
397 | static ssize_t proc_sys_write(struct file *filp, const char __user *buf, |
398 | size_t count, loff_t *ppos) | |
399 | { | |
400 | return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); | |
77b14db5 EB |
401 | } |
402 | ||
f1ecf068 LDM |
403 | static int proc_sys_open(struct inode *inode, struct file *filp) |
404 | { | |
405 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
406 | ||
407 | if (table->poll) | |
408 | filp->private_data = proc_sys_poll_event(table->poll); | |
409 | ||
410 | return 0; | |
411 | } | |
412 | ||
413 | static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) | |
414 | { | |
415 | struct inode *inode = filp->f_path.dentry->d_inode; | |
416 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
417 | unsigned long event = (unsigned long)filp->private_data; | |
418 | unsigned int ret = DEFAULT_POLLMASK; | |
419 | ||
420 | if (!table->proc_handler) | |
421 | goto out; | |
422 | ||
423 | if (!table->poll) | |
424 | goto out; | |
425 | ||
426 | poll_wait(filp, &table->poll->wait, wait); | |
427 | ||
428 | if (event != atomic_read(&table->poll->event)) { | |
429 | filp->private_data = proc_sys_poll_event(table->poll); | |
430 | ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; | |
431 | } | |
432 | ||
433 | out: | |
434 | return ret; | |
435 | } | |
77b14db5 EB |
436 | |
437 | static int proc_sys_fill_cache(struct file *filp, void *dirent, | |
9043476f AV |
438 | filldir_t filldir, |
439 | struct ctl_table_header *head, | |
440 | struct ctl_table *table) | |
77b14db5 | 441 | { |
77b14db5 EB |
442 | struct dentry *child, *dir = filp->f_path.dentry; |
443 | struct inode *inode; | |
444 | struct qstr qname; | |
445 | ino_t ino = 0; | |
446 | unsigned type = DT_UNKNOWN; | |
77b14db5 EB |
447 | |
448 | qname.name = table->procname; | |
449 | qname.len = strlen(table->procname); | |
450 | qname.hash = full_name_hash(qname.name, qname.len); | |
451 | ||
77b14db5 EB |
452 | child = d_lookup(dir, &qname); |
453 | if (!child) { | |
9043476f AV |
454 | child = d_alloc(dir, &qname); |
455 | if (child) { | |
456 | inode = proc_sys_make_inode(dir->d_sb, head, table); | |
457 | if (!inode) { | |
458 | dput(child); | |
459 | return -ENOMEM; | |
460 | } else { | |
fb045adb | 461 | d_set_d_op(child, &proc_sys_dentry_operations); |
9043476f | 462 | d_add(child, inode); |
77b14db5 | 463 | } |
9043476f AV |
464 | } else { |
465 | return -ENOMEM; | |
77b14db5 EB |
466 | } |
467 | } | |
77b14db5 | 468 | inode = child->d_inode; |
9043476f AV |
469 | ino = inode->i_ino; |
470 | type = inode->i_mode >> 12; | |
77b14db5 | 471 | dput(child); |
9043476f AV |
472 | return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type); |
473 | } | |
474 | ||
475 | static int scan(struct ctl_table_header *head, ctl_table *table, | |
476 | unsigned long *pos, struct file *file, | |
477 | void *dirent, filldir_t filldir) | |
478 | { | |
479 | ||
2315ffa0 | 480 | for (; table->procname; table++, (*pos)++) { |
9043476f AV |
481 | int res; |
482 | ||
9043476f AV |
483 | if (*pos < file->f_pos) |
484 | continue; | |
485 | ||
486 | res = proc_sys_fill_cache(file, dirent, filldir, head, table); | |
487 | if (res) | |
488 | return res; | |
489 | ||
490 | file->f_pos = *pos + 1; | |
491 | } | |
492 | return 0; | |
77b14db5 EB |
493 | } |
494 | ||
495 | static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir) | |
496 | { | |
9043476f | 497 | struct dentry *dentry = filp->f_path.dentry; |
77b14db5 | 498 | struct inode *inode = dentry->d_inode; |
9043476f AV |
499 | struct ctl_table_header *head = grab_header(inode); |
500 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
501 | struct ctl_table_header *h = NULL; | |
77b14db5 | 502 | unsigned long pos; |
9043476f AV |
503 | int ret = -EINVAL; |
504 | ||
505 | if (IS_ERR(head)) | |
506 | return PTR_ERR(head); | |
77b14db5 | 507 | |
9043476f AV |
508 | if (table && !table->child) { |
509 | WARN_ON(1); | |
77b14db5 | 510 | goto out; |
9043476f AV |
511 | } |
512 | ||
513 | table = table ? table->child : head->ctl_table; | |
77b14db5 EB |
514 | |
515 | ret = 0; | |
516 | /* Avoid a switch here: arm builds fail with missing __cmpdi2 */ | |
517 | if (filp->f_pos == 0) { | |
518 | if (filldir(dirent, ".", 1, filp->f_pos, | |
519 | inode->i_ino, DT_DIR) < 0) | |
520 | goto out; | |
521 | filp->f_pos++; | |
522 | } | |
523 | if (filp->f_pos == 1) { | |
524 | if (filldir(dirent, "..", 2, filp->f_pos, | |
525 | parent_ino(dentry), DT_DIR) < 0) | |
526 | goto out; | |
527 | filp->f_pos++; | |
528 | } | |
529 | pos = 2; | |
530 | ||
9043476f AV |
531 | ret = scan(head, table, &pos, filp, dirent, filldir); |
532 | if (ret) | |
533 | goto out; | |
77b14db5 | 534 | |
9043476f AV |
535 | for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { |
536 | if (h->attached_to != table) | |
77b14db5 | 537 | continue; |
9043476f AV |
538 | ret = scan(h, h->attached_by, &pos, filp, dirent, filldir); |
539 | if (ret) { | |
540 | sysctl_head_finish(h); | |
541 | break; | |
77b14db5 EB |
542 | } |
543 | } | |
544 | ret = 1; | |
545 | out: | |
546 | sysctl_head_finish(head); | |
547 | return ret; | |
548 | } | |
549 | ||
10556cb2 | 550 | static int proc_sys_permission(struct inode *inode, int mask) |
77b14db5 EB |
551 | { |
552 | /* | |
553 | * sysctl entries that are not writeable, | |
554 | * are _NOT_ writeable, capabilities or not. | |
555 | */ | |
f696a365 MS |
556 | struct ctl_table_header *head; |
557 | struct ctl_table *table; | |
77b14db5 EB |
558 | int error; |
559 | ||
f696a365 MS |
560 | /* Executable files are not allowed under /proc/sys/ */ |
561 | if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) | |
562 | return -EACCES; | |
563 | ||
564 | head = grab_header(inode); | |
9043476f AV |
565 | if (IS_ERR(head)) |
566 | return PTR_ERR(head); | |
77b14db5 | 567 | |
f696a365 | 568 | table = PROC_I(inode)->sysctl_entry; |
9043476f AV |
569 | if (!table) /* global root - r-xr-xr-x */ |
570 | error = mask & MAY_WRITE ? -EACCES : 0; | |
571 | else /* Use the permissions on the sysctl table entry */ | |
1fc0f78c | 572 | error = sysctl_perm(head->root, table, mask & ~MAY_NOT_BLOCK); |
77b14db5 | 573 | |
77b14db5 EB |
574 | sysctl_head_finish(head); |
575 | return error; | |
576 | } | |
577 | ||
578 | static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) | |
579 | { | |
580 | struct inode *inode = dentry->d_inode; | |
581 | int error; | |
582 | ||
583 | if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) | |
584 | return -EPERM; | |
585 | ||
586 | error = inode_change_ok(inode, attr); | |
1025774c CH |
587 | if (error) |
588 | return error; | |
589 | ||
590 | if ((attr->ia_valid & ATTR_SIZE) && | |
591 | attr->ia_size != i_size_read(inode)) { | |
592 | error = vmtruncate(inode, attr->ia_size); | |
593 | if (error) | |
594 | return error; | |
595 | } | |
77b14db5 | 596 | |
1025774c CH |
597 | setattr_copy(inode, attr); |
598 | mark_inode_dirty(inode); | |
599 | return 0; | |
77b14db5 EB |
600 | } |
601 | ||
9043476f AV |
602 | static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) |
603 | { | |
604 | struct inode *inode = dentry->d_inode; | |
605 | struct ctl_table_header *head = grab_header(inode); | |
606 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
607 | ||
608 | if (IS_ERR(head)) | |
609 | return PTR_ERR(head); | |
610 | ||
611 | generic_fillattr(inode, stat); | |
612 | if (table) | |
613 | stat->mode = (stat->mode & S_IFMT) | table->mode; | |
614 | ||
615 | sysctl_head_finish(head); | |
616 | return 0; | |
617 | } | |
618 | ||
77b14db5 | 619 | static const struct file_operations proc_sys_file_operations = { |
f1ecf068 LDM |
620 | .open = proc_sys_open, |
621 | .poll = proc_sys_poll, | |
77b14db5 EB |
622 | .read = proc_sys_read, |
623 | .write = proc_sys_write, | |
6038f373 | 624 | .llseek = default_llseek, |
9043476f AV |
625 | }; |
626 | ||
627 | static const struct file_operations proc_sys_dir_file_operations = { | |
887df078 | 628 | .read = generic_read_dir, |
77b14db5 | 629 | .readdir = proc_sys_readdir, |
3222a3e5 | 630 | .llseek = generic_file_llseek, |
77b14db5 EB |
631 | }; |
632 | ||
03a44825 | 633 | static const struct inode_operations proc_sys_inode_operations = { |
9043476f AV |
634 | .permission = proc_sys_permission, |
635 | .setattr = proc_sys_setattr, | |
636 | .getattr = proc_sys_getattr, | |
637 | }; | |
638 | ||
639 | static const struct inode_operations proc_sys_dir_operations = { | |
77b14db5 EB |
640 | .lookup = proc_sys_lookup, |
641 | .permission = proc_sys_permission, | |
642 | .setattr = proc_sys_setattr, | |
9043476f | 643 | .getattr = proc_sys_getattr, |
77b14db5 EB |
644 | }; |
645 | ||
646 | static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd) | |
647 | { | |
34286d66 NP |
648 | if (nd->flags & LOOKUP_RCU) |
649 | return -ECHILD; | |
9043476f AV |
650 | return !PROC_I(dentry->d_inode)->sysctl->unregistering; |
651 | } | |
652 | ||
fe15ce44 | 653 | static int proc_sys_delete(const struct dentry *dentry) |
9043476f AV |
654 | { |
655 | return !!PROC_I(dentry->d_inode)->sysctl->unregistering; | |
656 | } | |
657 | ||
1f87f0b5 EB |
658 | static int sysctl_is_seen(struct ctl_table_header *p) |
659 | { | |
660 | struct ctl_table_set *set = p->set; | |
661 | int res; | |
662 | spin_lock(&sysctl_lock); | |
663 | if (p->unregistering) | |
664 | res = 0; | |
665 | else if (!set->is_seen) | |
666 | res = 1; | |
667 | else | |
668 | res = set->is_seen(set); | |
669 | spin_unlock(&sysctl_lock); | |
670 | return res; | |
671 | } | |
672 | ||
621e155a NP |
673 | static int proc_sys_compare(const struct dentry *parent, |
674 | const struct inode *pinode, | |
675 | const struct dentry *dentry, const struct inode *inode, | |
676 | unsigned int len, const char *str, const struct qstr *name) | |
9043476f | 677 | { |
dfef6dcd | 678 | struct ctl_table_header *head; |
31e6b01f NP |
679 | /* Although proc doesn't have negative dentries, rcu-walk means |
680 | * that inode here can be NULL */ | |
dfef6dcd | 681 | /* AV: can it, indeed? */ |
31e6b01f | 682 | if (!inode) |
dfef6dcd | 683 | return 1; |
621e155a | 684 | if (name->len != len) |
9043476f | 685 | return 1; |
621e155a | 686 | if (memcmp(name->name, str, len)) |
9043476f | 687 | return 1; |
dfef6dcd AV |
688 | head = rcu_dereference(PROC_I(inode)->sysctl); |
689 | return !head || !sysctl_is_seen(head); | |
77b14db5 EB |
690 | } |
691 | ||
d72f71eb | 692 | static const struct dentry_operations proc_sys_dentry_operations = { |
77b14db5 | 693 | .d_revalidate = proc_sys_revalidate, |
9043476f AV |
694 | .d_delete = proc_sys_delete, |
695 | .d_compare = proc_sys_compare, | |
77b14db5 EB |
696 | }; |
697 | ||
1f87f0b5 EB |
698 | static struct ctl_table *is_branch_in(struct ctl_table *branch, |
699 | struct ctl_table *table) | |
700 | { | |
701 | struct ctl_table *p; | |
702 | const char *s = branch->procname; | |
703 | ||
704 | /* branch should have named subdirectory as its first element */ | |
705 | if (!s || !branch->child) | |
706 | return NULL; | |
707 | ||
708 | /* ... and nothing else */ | |
709 | if (branch[1].procname) | |
710 | return NULL; | |
711 | ||
712 | /* table should contain subdirectory with the same name */ | |
713 | for (p = table; p->procname; p++) { | |
714 | if (!p->child) | |
715 | continue; | |
716 | if (p->procname && strcmp(p->procname, s) == 0) | |
717 | return p; | |
718 | } | |
719 | return NULL; | |
720 | } | |
721 | ||
722 | /* see if attaching q to p would be an improvement */ | |
723 | static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q) | |
724 | { | |
725 | struct ctl_table *to = p->ctl_table, *by = q->ctl_table; | |
726 | struct ctl_table *next; | |
727 | int is_better = 0; | |
728 | int not_in_parent = !p->attached_by; | |
729 | ||
730 | while ((next = is_branch_in(by, to)) != NULL) { | |
731 | if (by == q->attached_by) | |
732 | is_better = 1; | |
733 | if (to == p->attached_by) | |
734 | not_in_parent = 1; | |
735 | by = by->child; | |
736 | to = next->child; | |
737 | } | |
738 | ||
739 | if (is_better && not_in_parent) { | |
740 | q->attached_by = by; | |
741 | q->attached_to = to; | |
742 | q->parent = p; | |
743 | } | |
744 | } | |
745 | ||
7c60c48f EB |
746 | static int sysctl_check_table_dups(const char *path, struct ctl_table *old, |
747 | struct ctl_table *table) | |
1f87f0b5 | 748 | { |
7c60c48f EB |
749 | struct ctl_table *entry, *test; |
750 | int error = 0; | |
1f87f0b5 | 751 | |
7c60c48f EB |
752 | for (entry = old; entry->procname; entry++) { |
753 | for (test = table; test->procname; test++) { | |
754 | if (strcmp(entry->procname, test->procname) == 0) { | |
755 | printk(KERN_ERR "sysctl duplicate entry: %s/%s\n", | |
756 | path, test->procname); | |
757 | error = -EEXIST; | |
758 | } | |
759 | } | |
760 | } | |
761 | return error; | |
1f87f0b5 EB |
762 | } |
763 | ||
7c60c48f EB |
764 | static int sysctl_check_dups(struct nsproxy *namespaces, |
765 | struct ctl_table_header *header, | |
766 | const char *path, struct ctl_table *table) | |
1f87f0b5 | 767 | { |
7c60c48f EB |
768 | struct ctl_table_root *root; |
769 | struct ctl_table_set *set; | |
770 | struct ctl_table_header *dir_head, *head; | |
771 | struct ctl_table *dir_table; | |
772 | int error = 0; | |
1f87f0b5 | 773 | |
7c60c48f EB |
774 | /* No dups if we are the only member of our directory */ |
775 | if (header->attached_by != table) | |
776 | return 0; | |
1f87f0b5 | 777 | |
7c60c48f EB |
778 | dir_head = header->parent; |
779 | dir_table = header->attached_to; | |
1f87f0b5 | 780 | |
7c60c48f | 781 | error = sysctl_check_table_dups(path, dir_table, table); |
1f87f0b5 | 782 | |
7c60c48f EB |
783 | root = &sysctl_table_root; |
784 | do { | |
785 | set = lookup_header_set(root, namespaces); | |
1f87f0b5 | 786 | |
7c60c48f EB |
787 | list_for_each_entry(head, &set->list, ctl_entry) { |
788 | if (head->unregistering) | |
1f87f0b5 | 789 | continue; |
7c60c48f EB |
790 | if (head->attached_to != dir_table) |
791 | continue; | |
792 | error = sysctl_check_table_dups(path, head->attached_by, | |
793 | table); | |
1f87f0b5 | 794 | } |
7c60c48f EB |
795 | root = list_entry(root->root_list.next, |
796 | struct ctl_table_root, root_list); | |
797 | } while (root != &sysctl_table_root); | |
798 | return error; | |
1f87f0b5 EB |
799 | } |
800 | ||
7c60c48f | 801 | static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) |
1f87f0b5 | 802 | { |
7c60c48f EB |
803 | struct va_format vaf; |
804 | va_list args; | |
1f87f0b5 | 805 | |
7c60c48f EB |
806 | va_start(args, fmt); |
807 | vaf.fmt = fmt; | |
808 | vaf.va = &args; | |
809 | ||
810 | printk(KERN_ERR "sysctl table check failed: %s/%s %pV\n", | |
811 | path, table->procname, &vaf); | |
1f87f0b5 | 812 | |
7c60c48f EB |
813 | va_end(args); |
814 | return -EINVAL; | |
1f87f0b5 EB |
815 | } |
816 | ||
7c60c48f | 817 | static int sysctl_check_table(const char *path, struct ctl_table *table) |
1f87f0b5 | 818 | { |
7c60c48f | 819 | int err = 0; |
1f87f0b5 | 820 | for (; table->procname; table++) { |
1f87f0b5 | 821 | if (table->child) |
7c60c48f EB |
822 | err = sysctl_err(path, table, "Not a file"); |
823 | ||
824 | if ((table->proc_handler == proc_dostring) || | |
825 | (table->proc_handler == proc_dointvec) || | |
826 | (table->proc_handler == proc_dointvec_minmax) || | |
827 | (table->proc_handler == proc_dointvec_jiffies) || | |
828 | (table->proc_handler == proc_dointvec_userhz_jiffies) || | |
829 | (table->proc_handler == proc_dointvec_ms_jiffies) || | |
830 | (table->proc_handler == proc_doulongvec_minmax) || | |
831 | (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { | |
832 | if (!table->data) | |
833 | err = sysctl_err(path, table, "No data"); | |
834 | if (!table->maxlen) | |
835 | err = sysctl_err(path, table, "No maxlen"); | |
836 | } | |
837 | if (!table->proc_handler) | |
838 | err = sysctl_err(path, table, "No proc_handler"); | |
839 | ||
840 | if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) | |
841 | err = sysctl_err(path, table, "bogus .mode 0%o", | |
842 | table->mode); | |
1f87f0b5 | 843 | } |
7c60c48f | 844 | return err; |
1f87f0b5 | 845 | } |
1f87f0b5 EB |
846 | |
847 | /** | |
f728019b | 848 | * __register_sysctl_table - register a leaf sysctl table |
1f87f0b5 EB |
849 | * @root: List of sysctl headers to register on |
850 | * @namespaces: Data to compute which lists of sysctl entries are visible | |
851 | * @path: The path to the directory the sysctl table is in. | |
852 | * @table: the top-level table structure | |
853 | * | |
854 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
855 | * array. A completely 0 filled entry terminates the table. | |
856 | * | |
857 | * The members of the &struct ctl_table structure are used as follows: | |
858 | * | |
859 | * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not | |
860 | * enter a sysctl file | |
861 | * | |
862 | * data - a pointer to data for use by proc_handler | |
863 | * | |
864 | * maxlen - the maximum size in bytes of the data | |
865 | * | |
f728019b | 866 | * mode - the file permissions for the /proc/sys file |
1f87f0b5 | 867 | * |
f728019b | 868 | * child - must be %NULL. |
1f87f0b5 EB |
869 | * |
870 | * proc_handler - the text handler routine (described below) | |
871 | * | |
1f87f0b5 EB |
872 | * extra1, extra2 - extra pointers usable by the proc handler routines |
873 | * | |
874 | * Leaf nodes in the sysctl tree will be represented by a single file | |
875 | * under /proc; non-leaf nodes will be represented by directories. | |
876 | * | |
f728019b EB |
877 | * There must be a proc_handler routine for any terminal nodes. |
878 | * Several default handlers are available to cover common cases - | |
1f87f0b5 EB |
879 | * |
880 | * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), | |
881 | * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), | |
882 | * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() | |
883 | * | |
884 | * It is the handler's job to read the input buffer from user memory | |
885 | * and process it. The handler should return 0 on success. | |
886 | * | |
887 | * This routine returns %NULL on a failure to register, and a pointer | |
888 | * to the table header on success. | |
889 | */ | |
6e9d5164 | 890 | struct ctl_table_header *__register_sysctl_table( |
1f87f0b5 EB |
891 | struct ctl_table_root *root, |
892 | struct nsproxy *namespaces, | |
6e9d5164 | 893 | const char *path, struct ctl_table *table) |
1f87f0b5 EB |
894 | { |
895 | struct ctl_table_header *header; | |
896 | struct ctl_table *new, **prevp; | |
6e9d5164 EB |
897 | const char *name, *nextname; |
898 | unsigned int npath = 0; | |
1f87f0b5 | 899 | struct ctl_table_set *set; |
f05e53a7 EB |
900 | size_t path_bytes = 0; |
901 | char *new_name; | |
1f87f0b5 EB |
902 | |
903 | /* Count the path components */ | |
6e9d5164 EB |
904 | for (name = path; name; name = nextname) { |
905 | int namelen; | |
906 | nextname = strchr(name, '/'); | |
907 | if (nextname) { | |
908 | namelen = nextname - name; | |
909 | nextname++; | |
910 | } else { | |
911 | namelen = strlen(name); | |
912 | } | |
913 | if (namelen == 0) | |
914 | continue; | |
915 | path_bytes += namelen + 1; | |
916 | npath++; | |
917 | } | |
1f87f0b5 EB |
918 | |
919 | /* | |
920 | * For each path component, allocate a 2-element ctl_table array. | |
921 | * The first array element will be filled with the sysctl entry | |
922 | * for this, the second will be the sentinel (procname == 0). | |
923 | * | |
924 | * We allocate everything in one go so that we don't have to | |
925 | * worry about freeing additional memory in unregister_sysctl_table. | |
926 | */ | |
f05e53a7 | 927 | header = kzalloc(sizeof(struct ctl_table_header) + path_bytes + |
1f87f0b5 EB |
928 | (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL); |
929 | if (!header) | |
930 | return NULL; | |
931 | ||
932 | new = (struct ctl_table *) (header + 1); | |
f05e53a7 | 933 | new_name = (char *)(new + (2 * npath)); |
1f87f0b5 EB |
934 | |
935 | /* Now connect the dots */ | |
936 | prevp = &header->ctl_table; | |
6e9d5164 EB |
937 | for (name = path; name; name = nextname) { |
938 | int namelen; | |
939 | nextname = strchr(name, '/'); | |
940 | if (nextname) { | |
941 | namelen = nextname - name; | |
942 | nextname++; | |
943 | } else { | |
944 | namelen = strlen(name); | |
945 | } | |
946 | if (namelen == 0) | |
947 | continue; | |
948 | memcpy(new_name, name, namelen); | |
949 | new_name[namelen] = '\0'; | |
950 | ||
f05e53a7 | 951 | new->procname = new_name; |
1f87f0b5 EB |
952 | new->mode = 0555; |
953 | ||
954 | *prevp = new; | |
955 | prevp = &new->child; | |
956 | ||
957 | new += 2; | |
6e9d5164 | 958 | new_name += namelen + 1; |
1f87f0b5 EB |
959 | } |
960 | *prevp = table; | |
e0d04529 EB |
961 | |
962 | init_header(header, root, NULL, table); | |
7c60c48f EB |
963 | if (sysctl_check_table(path, table)) |
964 | goto fail; | |
8d6ecfcc | 965 | |
1f87f0b5 EB |
966 | spin_lock(&sysctl_lock); |
967 | header->set = lookup_header_set(root, namespaces); | |
968 | header->attached_by = header->ctl_table; | |
969 | header->attached_to = root_table; | |
970 | header->parent = &root_table_header; | |
bd295b56 EB |
971 | set = header->set; |
972 | root = header->root; | |
973 | for (;;) { | |
1f87f0b5 EB |
974 | struct ctl_table_header *p; |
975 | list_for_each_entry(p, &set->list, ctl_entry) { | |
976 | if (p->unregistering) | |
977 | continue; | |
978 | try_attach(p, header); | |
979 | } | |
bd295b56 EB |
980 | if (root == &sysctl_table_root) |
981 | break; | |
982 | root = list_entry(root->root_list.prev, | |
983 | struct ctl_table_root, root_list); | |
984 | set = lookup_header_set(root, namespaces); | |
1f87f0b5 | 985 | } |
7c60c48f EB |
986 | if (sysctl_check_dups(namespaces, header, path, table)) |
987 | goto fail_locked; | |
8425d6aa | 988 | insert_header(header); |
1f87f0b5 EB |
989 | spin_unlock(&sysctl_lock); |
990 | ||
991 | return header; | |
7c60c48f EB |
992 | fail_locked: |
993 | spin_unlock(&sysctl_lock); | |
994 | fail: | |
995 | kfree(header); | |
996 | dump_stack(); | |
997 | return NULL; | |
1f87f0b5 EB |
998 | } |
999 | ||
6e9d5164 EB |
1000 | static char *append_path(const char *path, char *pos, const char *name) |
1001 | { | |
1002 | int namelen; | |
1003 | namelen = strlen(name); | |
1004 | if (((pos - path) + namelen + 2) >= PATH_MAX) | |
1005 | return NULL; | |
1006 | memcpy(pos, name, namelen); | |
1007 | pos[namelen] = '/'; | |
1008 | pos[namelen + 1] = '\0'; | |
1009 | pos += namelen + 1; | |
1010 | return pos; | |
1011 | } | |
1012 | ||
f728019b EB |
1013 | static int count_subheaders(struct ctl_table *table) |
1014 | { | |
1015 | int has_files = 0; | |
1016 | int nr_subheaders = 0; | |
1017 | struct ctl_table *entry; | |
1018 | ||
1019 | /* special case: no directory and empty directory */ | |
1020 | if (!table || !table->procname) | |
1021 | return 1; | |
1022 | ||
1023 | for (entry = table; entry->procname; entry++) { | |
1024 | if (entry->child) | |
1025 | nr_subheaders += count_subheaders(entry->child); | |
1026 | else | |
1027 | has_files = 1; | |
1028 | } | |
1029 | return nr_subheaders + has_files; | |
1030 | } | |
1031 | ||
1032 | static int register_leaf_sysctl_tables(const char *path, char *pos, | |
1033 | struct ctl_table_header ***subheader, | |
1034 | struct ctl_table_root *root, struct nsproxy *namespaces, | |
1035 | struct ctl_table *table) | |
1036 | { | |
1037 | struct ctl_table *ctl_table_arg = NULL; | |
1038 | struct ctl_table *entry, *files; | |
1039 | int nr_files = 0; | |
1040 | int nr_dirs = 0; | |
1041 | int err = -ENOMEM; | |
1042 | ||
1043 | for (entry = table; entry->procname; entry++) { | |
1044 | if (entry->child) | |
1045 | nr_dirs++; | |
1046 | else | |
1047 | nr_files++; | |
1048 | } | |
1049 | ||
1050 | files = table; | |
1051 | /* If there are mixed files and directories we need a new table */ | |
1052 | if (nr_dirs && nr_files) { | |
1053 | struct ctl_table *new; | |
1054 | files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), | |
1055 | GFP_KERNEL); | |
1056 | if (!files) | |
1057 | goto out; | |
1058 | ||
1059 | ctl_table_arg = files; | |
1060 | for (new = files, entry = table; entry->procname; entry++) { | |
1061 | if (entry->child) | |
1062 | continue; | |
1063 | *new = *entry; | |
1064 | new++; | |
1065 | } | |
1066 | } | |
1067 | ||
1068 | /* Register everything except a directory full of subdirectories */ | |
1069 | if (nr_files || !nr_dirs) { | |
1070 | struct ctl_table_header *header; | |
1071 | header = __register_sysctl_table(root, namespaces, path, files); | |
1072 | if (!header) { | |
1073 | kfree(ctl_table_arg); | |
1074 | goto out; | |
1075 | } | |
1076 | ||
1077 | /* Remember if we need to free the file table */ | |
1078 | header->ctl_table_arg = ctl_table_arg; | |
1079 | **subheader = header; | |
1080 | (*subheader)++; | |
1081 | } | |
1082 | ||
1083 | /* Recurse into the subdirectories. */ | |
1084 | for (entry = table; entry->procname; entry++) { | |
1085 | char *child_pos; | |
1086 | ||
1087 | if (!entry->child) | |
1088 | continue; | |
1089 | ||
1090 | err = -ENAMETOOLONG; | |
1091 | child_pos = append_path(path, pos, entry->procname); | |
1092 | if (!child_pos) | |
1093 | goto out; | |
1094 | ||
1095 | err = register_leaf_sysctl_tables(path, child_pos, subheader, | |
1096 | root, namespaces, entry->child); | |
1097 | pos[0] = '\0'; | |
1098 | if (err) | |
1099 | goto out; | |
1100 | } | |
1101 | err = 0; | |
1102 | out: | |
1103 | /* On failure our caller will unregister all registered subheaders */ | |
1104 | return err; | |
1105 | } | |
1106 | ||
6e9d5164 EB |
1107 | /** |
1108 | * __register_sysctl_paths - register a sysctl table hierarchy | |
1109 | * @root: List of sysctl headers to register on | |
1110 | * @namespaces: Data to compute which lists of sysctl entries are visible | |
1111 | * @path: The path to the directory the sysctl table is in. | |
1112 | * @table: the top-level table structure | |
1113 | * | |
1114 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1115 | * array. A completely 0 filled entry terminates the table. | |
1116 | * | |
1117 | * See __register_sysctl_table for more details. | |
1118 | */ | |
1119 | struct ctl_table_header *__register_sysctl_paths( | |
1120 | struct ctl_table_root *root, | |
1121 | struct nsproxy *namespaces, | |
1122 | const struct ctl_path *path, struct ctl_table *table) | |
1123 | { | |
ec6a5266 | 1124 | struct ctl_table *ctl_table_arg = table; |
f728019b EB |
1125 | int nr_subheaders = count_subheaders(table); |
1126 | struct ctl_table_header *header = NULL, **subheaders, **subheader; | |
6e9d5164 EB |
1127 | const struct ctl_path *component; |
1128 | char *new_path, *pos; | |
1129 | ||
1130 | pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); | |
1131 | if (!new_path) | |
1132 | return NULL; | |
1133 | ||
1134 | pos[0] = '\0'; | |
1135 | for (component = path; component->procname; component++) { | |
1136 | pos = append_path(new_path, pos, component->procname); | |
1137 | if (!pos) | |
1138 | goto out; | |
1139 | } | |
ec6a5266 EB |
1140 | while (table->procname && table->child && !table[1].procname) { |
1141 | pos = append_path(new_path, pos, table->procname); | |
1142 | if (!pos) | |
1143 | goto out; | |
1144 | table = table->child; | |
1145 | } | |
f728019b EB |
1146 | if (nr_subheaders == 1) { |
1147 | header = __register_sysctl_table(root, namespaces, new_path, table); | |
1148 | if (header) | |
1149 | header->ctl_table_arg = ctl_table_arg; | |
1150 | } else { | |
1151 | header = kzalloc(sizeof(*header) + | |
1152 | sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); | |
1153 | if (!header) | |
1154 | goto out; | |
1155 | ||
1156 | subheaders = (struct ctl_table_header **) (header + 1); | |
1157 | subheader = subheaders; | |
ec6a5266 | 1158 | header->ctl_table_arg = ctl_table_arg; |
f728019b EB |
1159 | |
1160 | if (register_leaf_sysctl_tables(new_path, pos, &subheader, | |
1161 | root, namespaces, table)) | |
1162 | goto err_register_leaves; | |
1163 | } | |
1164 | ||
6e9d5164 EB |
1165 | out: |
1166 | kfree(new_path); | |
1167 | return header; | |
f728019b EB |
1168 | |
1169 | err_register_leaves: | |
1170 | while (subheader > subheaders) { | |
1171 | struct ctl_table_header *subh = *(--subheader); | |
1172 | struct ctl_table *table = subh->ctl_table_arg; | |
1173 | unregister_sysctl_table(subh); | |
1174 | kfree(table); | |
1175 | } | |
1176 | kfree(header); | |
1177 | header = NULL; | |
1178 | goto out; | |
6e9d5164 EB |
1179 | } |
1180 | ||
1f87f0b5 EB |
1181 | /** |
1182 | * register_sysctl_table_path - register a sysctl table hierarchy | |
1183 | * @path: The path to the directory the sysctl table is in. | |
1184 | * @table: the top-level table structure | |
1185 | * | |
1186 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1187 | * array. A completely 0 filled entry terminates the table. | |
1188 | * | |
1189 | * See __register_sysctl_paths for more details. | |
1190 | */ | |
1191 | struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, | |
1192 | struct ctl_table *table) | |
1193 | { | |
1194 | return __register_sysctl_paths(&sysctl_table_root, current->nsproxy, | |
1195 | path, table); | |
1196 | } | |
1197 | EXPORT_SYMBOL(register_sysctl_paths); | |
1198 | ||
1199 | /** | |
1200 | * register_sysctl_table - register a sysctl table hierarchy | |
1201 | * @table: the top-level table structure | |
1202 | * | |
1203 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1204 | * array. A completely 0 filled entry terminates the table. | |
1205 | * | |
1206 | * See register_sysctl_paths for more details. | |
1207 | */ | |
1208 | struct ctl_table_header *register_sysctl_table(struct ctl_table *table) | |
1209 | { | |
1210 | static const struct ctl_path null_path[] = { {} }; | |
1211 | ||
1212 | return register_sysctl_paths(null_path, table); | |
1213 | } | |
1214 | EXPORT_SYMBOL(register_sysctl_table); | |
1215 | ||
938aaa4f EB |
1216 | static void drop_sysctl_table(struct ctl_table_header *header) |
1217 | { | |
1218 | if (--header->nreg) | |
1219 | return; | |
1220 | ||
1221 | start_unregistering(header); | |
1222 | if (!--header->parent->count) { | |
1223 | WARN_ON(1); | |
1224 | kfree_rcu(header->parent, rcu); | |
1225 | } | |
1226 | if (!--header->count) | |
1227 | kfree_rcu(header, rcu); | |
1228 | } | |
1229 | ||
1f87f0b5 EB |
1230 | /** |
1231 | * unregister_sysctl_table - unregister a sysctl table hierarchy | |
1232 | * @header: the header returned from register_sysctl_table | |
1233 | * | |
1234 | * Unregisters the sysctl table and all children. proc entries may not | |
1235 | * actually be removed until they are no longer used by anyone. | |
1236 | */ | |
1237 | void unregister_sysctl_table(struct ctl_table_header * header) | |
1238 | { | |
f728019b | 1239 | int nr_subheaders; |
1f87f0b5 EB |
1240 | might_sleep(); |
1241 | ||
1242 | if (header == NULL) | |
1243 | return; | |
1244 | ||
f728019b EB |
1245 | nr_subheaders = count_subheaders(header->ctl_table_arg); |
1246 | if (unlikely(nr_subheaders > 1)) { | |
1247 | struct ctl_table_header **subheaders; | |
1248 | int i; | |
1249 | ||
1250 | subheaders = (struct ctl_table_header **)(header + 1); | |
1251 | for (i = nr_subheaders -1; i >= 0; i--) { | |
1252 | struct ctl_table_header *subh = subheaders[i]; | |
1253 | struct ctl_table *table = subh->ctl_table_arg; | |
1254 | unregister_sysctl_table(subh); | |
1255 | kfree(table); | |
1256 | } | |
1257 | kfree(header); | |
1258 | return; | |
1259 | } | |
1260 | ||
1f87f0b5 | 1261 | spin_lock(&sysctl_lock); |
938aaa4f | 1262 | drop_sysctl_table(header); |
1f87f0b5 EB |
1263 | spin_unlock(&sysctl_lock); |
1264 | } | |
1265 | EXPORT_SYMBOL(unregister_sysctl_table); | |
1266 | ||
1267 | void setup_sysctl_set(struct ctl_table_set *p, | |
1f87f0b5 EB |
1268 | int (*is_seen)(struct ctl_table_set *)) |
1269 | { | |
1270 | INIT_LIST_HEAD(&p->list); | |
1f87f0b5 EB |
1271 | p->is_seen = is_seen; |
1272 | } | |
1273 | ||
97324cd8 EB |
1274 | void retire_sysctl_set(struct ctl_table_set *set) |
1275 | { | |
1276 | WARN_ON(!list_empty(&set->list)); | |
1277 | } | |
1f87f0b5 | 1278 | |
1e0edd3f | 1279 | int __init proc_sys_init(void) |
77b14db5 | 1280 | { |
e1675231 AD |
1281 | struct proc_dir_entry *proc_sys_root; |
1282 | ||
77b14db5 | 1283 | proc_sys_root = proc_mkdir("sys", NULL); |
9043476f AV |
1284 | proc_sys_root->proc_iops = &proc_sys_dir_operations; |
1285 | proc_sys_root->proc_fops = &proc_sys_dir_file_operations; | |
77b14db5 | 1286 | proc_sys_root->nlink = 0; |
de4e83bd EB |
1287 | |
1288 | return sysctl_init(); | |
77b14db5 | 1289 | } |