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