projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Merge tag 'for-3.10-rc1' of git://gitorious.org/linux-pwm/linux-pwm
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / proc / proc_sysctl.c
1 /*
2 * /proc/sys support
3 */
4 #include <linux/init.h>
5 #include <linux/sysctl.h>
6 #include <linux/poll.h>
7 #include <linux/proc_fs.h>
8 #include <linux/printk.h>
9 #include <linux/security.h>
10 #include <linux/sched.h>
11 #include <linux/namei.h>
12 #include <linux/mm.h>
13 #include <linux/module.h>
14 #include "internal.h"
15
16 static const struct dentry_operations proc_sys_dentry_operations;
17 static const struct file_operations proc_sys_file_operations;
18 static const struct inode_operations proc_sys_inode_operations;
19 static const struct file_operations proc_sys_dir_file_operations;
20 static const struct inode_operations proc_sys_dir_operations;
21
22 void proc_sys_poll_notify(struct ctl_table_poll *poll)
23 {
24 if (!poll)
25 return;
26
27 atomic_inc(&poll->event);
28 wake_up_interruptible(&poll->wait);
29 }
30
31 static struct ctl_table root_table[] = {
32 {
33 .procname = "",
34 .mode = S_IFDIR|S_IRUGO|S_IXUGO,
35 },
36 { }
37 };
38 static struct ctl_table_root sysctl_table_root = {
39 .default_set.dir.header = {
40 {{.count = 1,
41 .nreg = 1,
42 .ctl_table = root_table }},
43 .ctl_table_arg = root_table,
44 .root = &sysctl_table_root,
45 .set = &sysctl_table_root.default_set,
46 },
47 };
48
49 static DEFINE_SPINLOCK(sysctl_lock);
50
51 static void drop_sysctl_table(struct ctl_table_header *header);
52 static int sysctl_follow_link(struct ctl_table_header **phead,
53 struct ctl_table **pentry, struct nsproxy *namespaces);
54 static int insert_links(struct ctl_table_header *head);
55 static void put_links(struct ctl_table_header *header);
56
57 static void sysctl_print_dir(struct ctl_dir *dir)
58 {
59 if (dir->header.parent)
60 sysctl_print_dir(dir->header.parent);
61 pr_cont("%s/", dir->header.ctl_table[0].procname);
62 }
63
64 static int namecmp(const char *name1, int len1, const char *name2, int len2)
65 {
66 int minlen;
67 int cmp;
68
69 minlen = len1;
70 if (minlen > len2)
71 minlen = len2;
72
73 cmp = memcmp(name1, name2, minlen);
74 if (cmp == 0)
75 cmp = len1 - len2;
76 return cmp;
77 }
78
79 /* Called under sysctl_lock */
80 static struct ctl_table *find_entry(struct ctl_table_header **phead,
81 struct ctl_dir *dir, const char *name, int namelen)
82 {
83 struct ctl_table_header *head;
84 struct ctl_table *entry;
85 struct rb_node *node = dir->root.rb_node;
86
87 while (node)
88 {
89 struct ctl_node *ctl_node;
90 const char *procname;
91 int cmp;
92
93 ctl_node = rb_entry(node, struct ctl_node, node);
94 head = ctl_node->header;
95 entry = &head->ctl_table[ctl_node - head->node];
96 procname = entry->procname;
97
98 cmp = namecmp(name, namelen, procname, strlen(procname));
99 if (cmp < 0)
100 node = node->rb_left;
101 else if (cmp > 0)
102 node = node->rb_right;
103 else {
104 *phead = head;
105 return entry;
106 }
107 }
108 return NULL;
109 }
110
111 static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry)
112 {
113 struct rb_node *node = &head->node[entry - head->ctl_table].node;
114 struct rb_node **p = &head->parent->root.rb_node;
115 struct rb_node *parent = NULL;
116 const char *name = entry->procname;
117 int namelen = strlen(name);
118
119 while (*p) {
120 struct ctl_table_header *parent_head;
121 struct ctl_table *parent_entry;
122 struct ctl_node *parent_node;
123 const char *parent_name;
124 int cmp;
125
126 parent = *p;
127 parent_node = rb_entry(parent, struct ctl_node, node);
128 parent_head = parent_node->header;
129 parent_entry = &parent_head->ctl_table[parent_node - parent_head->node];
130 parent_name = parent_entry->procname;
131
132 cmp = namecmp(name, namelen, parent_name, strlen(parent_name));
133 if (cmp < 0)
134 p = &(*p)->rb_left;
135 else if (cmp > 0)
136 p = &(*p)->rb_right;
137 else {
138 pr_err("sysctl duplicate entry: ");
139 sysctl_print_dir(head->parent);
140 pr_cont("/%s\n", entry->procname);
141 return -EEXIST;
142 }
143 }
144
145 rb_link_node(node, parent, p);
146 rb_insert_color(node, &head->parent->root);
147 return 0;
148 }
149
150 static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry)
151 {
152 struct rb_node *node = &head->node[entry - head->ctl_table].node;
153
154 rb_erase(node, &head->parent->root);
155 }
156
157 static void init_header(struct ctl_table_header *head,
158 struct ctl_table_root *root, struct ctl_table_set *set,
159 struct ctl_node *node, struct ctl_table *table)
160 {
161 head->ctl_table = table;
162 head->ctl_table_arg = table;
163 head->used = 0;
164 head->count = 1;
165 head->nreg = 1;
166 head->unregistering = NULL;
167 head->root = root;
168 head->set = set;
169 head->parent = NULL;
170 head->node = node;
171 if (node) {
172 struct ctl_table *entry;
173 for (entry = table; entry->procname; entry++, node++)
174 node->header = head;
175 }
176 }
177
178 static void erase_header(struct ctl_table_header *head)
179 {
180 struct ctl_table *entry;
181 for (entry = head->ctl_table; entry->procname; entry++)
182 erase_entry(head, entry);
183 }
184
185 static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
186 {
187 struct ctl_table *entry;
188 int err;
189
190 dir->header.nreg++;
191 header->parent = dir;
192 err = insert_links(header);
193 if (err)
194 goto fail_links;
195 for (entry = header->ctl_table; entry->procname; entry++) {
196 err = insert_entry(header, entry);
197 if (err)
198 goto fail;
199 }
200 return 0;
201 fail:
202 erase_header(header);
203 put_links(header);
204 fail_links:
205 header->parent = NULL;
206 drop_sysctl_table(&dir->header);
207 return err;
208 }
209
210 /* called under sysctl_lock */
211 static int use_table(struct ctl_table_header *p)
212 {
213 if (unlikely(p->unregistering))
214 return 0;
215 p->used++;
216 return 1;
217 }
218
219 /* called under sysctl_lock */
220 static void unuse_table(struct ctl_table_header *p)
221 {
222 if (!--p->used)
223 if (unlikely(p->unregistering))
224 complete(p->unregistering);
225 }
226
227 /* called under sysctl_lock, will reacquire if has to wait */
228 static void start_unregistering(struct ctl_table_header *p)
229 {
230 /*
231 * if p->used is 0, nobody will ever touch that entry again;
232 * we'll eliminate all paths to it before dropping sysctl_lock
233 */
234 if (unlikely(p->used)) {
235 struct completion wait;
236 init_completion(&wait);
237 p->unregistering = &wait;
238 spin_unlock(&sysctl_lock);
239 wait_for_completion(&wait);
240 spin_lock(&sysctl_lock);
241 } else {
242 /* anything non-NULL; we'll never dereference it */
243 p->unregistering = ERR_PTR(-EINVAL);
244 }
245 /*
246 * do not remove from the list until nobody holds it; walking the
247 * list in do_sysctl() relies on that.
248 */
249 erase_header(p);
250 }
251
252 static void sysctl_head_get(struct ctl_table_header *head)
253 {
254 spin_lock(&sysctl_lock);
255 head->count++;
256 spin_unlock(&sysctl_lock);
257 }
258
259 void sysctl_head_put(struct ctl_table_header *head)
260 {
261 spin_lock(&sysctl_lock);
262 if (!--head->count)
263 kfree_rcu(head, rcu);
264 spin_unlock(&sysctl_lock);
265 }
266
267 static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
268 {
269 BUG_ON(!head);
270 spin_lock(&sysctl_lock);
271 if (!use_table(head))
272 head = ERR_PTR(-ENOENT);
273 spin_unlock(&sysctl_lock);
274 return head;
275 }
276
277 static void sysctl_head_finish(struct ctl_table_header *head)
278 {
279 if (!head)
280 return;
281 spin_lock(&sysctl_lock);
282 unuse_table(head);
283 spin_unlock(&sysctl_lock);
284 }
285
286 static struct ctl_table_set *
287 lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
288 {
289 struct ctl_table_set *set = &root->default_set;
290 if (root->lookup)
291 set = root->lookup(root, namespaces);
292 return set;
293 }
294
295 static struct ctl_table *lookup_entry(struct ctl_table_header **phead,
296 struct ctl_dir *dir,
297 const char *name, int namelen)
298 {
299 struct ctl_table_header *head;
300 struct ctl_table *entry;
301
302 spin_lock(&sysctl_lock);
303 entry = find_entry(&head, dir, name, namelen);
304 if (entry && use_table(head))
305 *phead = head;
306 else
307 entry = NULL;
308 spin_unlock(&sysctl_lock);
309 return entry;
310 }
311
312 static struct ctl_node *first_usable_entry(struct rb_node *node)
313 {
314 struct ctl_node *ctl_node;
315
316 for (;node; node = rb_next(node)) {
317 ctl_node = rb_entry(node, struct ctl_node, node);
318 if (use_table(ctl_node->header))
319 return ctl_node;
320 }
321 return NULL;
322 }
323
324 static void first_entry(struct ctl_dir *dir,
325 struct ctl_table_header **phead, struct ctl_table **pentry)
326 {
327 struct ctl_table_header *head = NULL;
328 struct ctl_table *entry = NULL;
329 struct ctl_node *ctl_node;
330
331 spin_lock(&sysctl_lock);
332 ctl_node = first_usable_entry(rb_first(&dir->root));
333 spin_unlock(&sysctl_lock);
334 if (ctl_node) {
335 head = ctl_node->header;
336 entry = &head->ctl_table[ctl_node - head->node];
337 }
338 *phead = head;
339 *pentry = entry;
340 }
341
342 static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry)
343 {
344 struct ctl_table_header *head = *phead;
345 struct ctl_table *entry = *pentry;
346 struct ctl_node *ctl_node = &head->node[entry - head->ctl_table];
347
348 spin_lock(&sysctl_lock);
349 unuse_table(head);
350
351 ctl_node = first_usable_entry(rb_next(&ctl_node->node));
352 spin_unlock(&sysctl_lock);
353 head = NULL;
354 if (ctl_node) {
355 head = ctl_node->header;
356 entry = &head->ctl_table[ctl_node - head->node];
357 }
358 *phead = head;
359 *pentry = entry;
360 }
361
362 void register_sysctl_root(struct ctl_table_root *root)
363 {
364 }
365
366 /*
367 * sysctl_perm does NOT grant the superuser all rights automatically, because
368 * some sysctl variables are readonly even to root.
369 */
370
371 static int test_perm(int mode, int op)
372 {
373 if (uid_eq(current_euid(), GLOBAL_ROOT_UID))
374 mode >>= 6;
375 else if (in_egroup_p(GLOBAL_ROOT_GID))
376 mode >>= 3;
377 if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
378 return 0;
379 return -EACCES;
380 }
381
382 static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op)
383 {
384 struct ctl_table_root *root = head->root;
385 int mode;
386
387 if (root->permissions)
388 mode = root->permissions(head, table);
389 else
390 mode = table->mode;
391
392 return test_perm(mode, op);
393 }
394
395 static struct inode *proc_sys_make_inode(struct super_block *sb,
396 struct ctl_table_header *head, struct ctl_table *table)
397 {
398 struct inode *inode;
399 struct proc_inode *ei;
400
401 inode = new_inode(sb);
402 if (!inode)
403 goto out;
404
405 inode->i_ino = get_next_ino();
406
407 sysctl_head_get(head);
408 ei = PROC_I(inode);
409 ei->sysctl = head;
410 ei->sysctl_entry = table;
411
412 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
413 inode->i_mode = table->mode;
414 if (!S_ISDIR(table->mode)) {
415 inode->i_mode |= S_IFREG;
416 inode->i_op = &proc_sys_inode_operations;
417 inode->i_fop = &proc_sys_file_operations;
418 } else {
419 inode->i_mode |= S_IFDIR;
420 inode->i_op = &proc_sys_dir_operations;
421 inode->i_fop = &proc_sys_dir_file_operations;
422 }
423 out:
424 return inode;
425 }
426
427 static struct ctl_table_header *grab_header(struct inode *inode)
428 {
429 struct ctl_table_header *head = PROC_I(inode)->sysctl;
430 if (!head)
431 head = &sysctl_table_root.default_set.dir.header;
432 return sysctl_head_grab(head);
433 }
434
435 static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
436 unsigned int flags)
437 {
438 struct ctl_table_header *head = grab_header(dir);
439 struct ctl_table_header *h = NULL;
440 struct qstr *name = &dentry->d_name;
441 struct ctl_table *p;
442 struct inode *inode;
443 struct dentry *err = ERR_PTR(-ENOENT);
444 struct ctl_dir *ctl_dir;
445 int ret;
446
447 if (IS_ERR(head))
448 return ERR_CAST(head);
449
450 ctl_dir = container_of(head, struct ctl_dir, header);
451
452 p = lookup_entry(&h, ctl_dir, name->name, name->len);
453 if (!p)
454 goto out;
455
456 if (S_ISLNK(p->mode)) {
457 ret = sysctl_follow_link(&h, &p, current->nsproxy);
458 err = ERR_PTR(ret);
459 if (ret)
460 goto out;
461 }
462
463 err = ERR_PTR(-ENOMEM);
464 inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
465 if (!inode)
466 goto out;
467
468 err = NULL;
469 d_set_d_op(dentry, &proc_sys_dentry_operations);
470 d_add(dentry, inode);
471
472 out:
473 if (h)
474 sysctl_head_finish(h);
475 sysctl_head_finish(head);
476 return err;
477 }
478
479 static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
480 size_t count, loff_t *ppos, int write)
481 {
482 struct inode *inode = file_inode(filp);
483 struct ctl_table_header *head = grab_header(inode);
484 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
485 ssize_t error;
486 size_t res;
487
488 if (IS_ERR(head))
489 return PTR_ERR(head);
490
491 /*
492 * At this point we know that the sysctl was not unregistered
493 * and won't be until we finish.
494 */
495 error = -EPERM;
496 if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ))
497 goto out;
498
499 /* if that can happen at all, it should be -EINVAL, not -EISDIR */
500 error = -EINVAL;
501 if (!table->proc_handler)
502 goto out;
503
504 /* careful: calling conventions are nasty here */
505 res = count;
506 error = table->proc_handler(table, write, buf, &res, ppos);
507 if (!error)
508 error = res;
509 out:
510 sysctl_head_finish(head);
511
512 return error;
513 }
514
515 static ssize_t proc_sys_read(struct file *filp, char __user *buf,
516 size_t count, loff_t *ppos)
517 {
518 return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
519 }
520
521 static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
522 size_t count, loff_t *ppos)
523 {
524 return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
525 }
526
527 static int proc_sys_open(struct inode *inode, struct file *filp)
528 {
529 struct ctl_table_header *head = grab_header(inode);
530 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
531
532 /* sysctl was unregistered */
533 if (IS_ERR(head))
534 return PTR_ERR(head);
535
536 if (table->poll)
537 filp->private_data = proc_sys_poll_event(table->poll);
538
539 sysctl_head_finish(head);
540
541 return 0;
542 }
543
544 static unsigned int proc_sys_poll(struct file *filp, poll_table *wait)
545 {
546 struct inode *inode = file_inode(filp);
547 struct ctl_table_header *head = grab_header(inode);
548 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
549 unsigned int ret = DEFAULT_POLLMASK;
550 unsigned long event;
551
552 /* sysctl was unregistered */
553 if (IS_ERR(head))
554 return POLLERR | POLLHUP;
555
556 if (!table->proc_handler)
557 goto out;
558
559 if (!table->poll)
560 goto out;
561
562 event = (unsigned long)filp->private_data;
563 poll_wait(filp, &table->poll->wait, wait);
564
565 if (event != atomic_read(&table->poll->event)) {
566 filp->private_data = proc_sys_poll_event(table->poll);
567 ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI;
568 }
569
570 out:
571 sysctl_head_finish(head);
572
573 return ret;
574 }
575
576 static int proc_sys_fill_cache(struct file *filp, void *dirent,
577 filldir_t filldir,
578 struct ctl_table_header *head,
579 struct ctl_table *table)
580 {
581 struct dentry *child, *dir = filp->f_path.dentry;
582 struct inode *inode;
583 struct qstr qname;
584 ino_t ino = 0;
585 unsigned type = DT_UNKNOWN;
586
587 qname.name = table->procname;
588 qname.len = strlen(table->procname);
589 qname.hash = full_name_hash(qname.name, qname.len);
590
591 child = d_lookup(dir, &qname);
592 if (!child) {
593 child = d_alloc(dir, &qname);
594 if (child) {
595 inode = proc_sys_make_inode(dir->d_sb, head, table);
596 if (!inode) {
597 dput(child);
598 return -ENOMEM;
599 } else {
600 d_set_d_op(child, &proc_sys_dentry_operations);
601 d_add(child, inode);
602 }
603 } else {
604 return -ENOMEM;
605 }
606 }
607 inode = child->d_inode;
608 ino = inode->i_ino;
609 type = inode->i_mode >> 12;
610 dput(child);
611 return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
612 }
613
614 static int proc_sys_link_fill_cache(struct file *filp, void *dirent,
615 filldir_t filldir,
616 struct ctl_table_header *head,
617 struct ctl_table *table)
618 {
619 int err, ret = 0;
620 head = sysctl_head_grab(head);
621
622 if (S_ISLNK(table->mode)) {
623 /* It is not an error if we can not follow the link ignore it */
624 err = sysctl_follow_link(&head, &table, current->nsproxy);
625 if (err)
626 goto out;
627 }
628
629 ret = proc_sys_fill_cache(filp, dirent, filldir, head, table);
630 out:
631 sysctl_head_finish(head);
632 return ret;
633 }
634
635 static int scan(struct ctl_table_header *head, ctl_table *table,
636 unsigned long *pos, struct file *file,
637 void *dirent, filldir_t filldir)
638 {
639 int res;
640
641 if ((*pos)++ < file->f_pos)
642 return 0;
643
644 if (unlikely(S_ISLNK(table->mode)))
645 res = proc_sys_link_fill_cache(file, dirent, filldir, head, table);
646 else
647 res = proc_sys_fill_cache(file, dirent, filldir, head, table);
648
649 if (res == 0)
650 file->f_pos = *pos;
651
652 return res;
653 }
654
655 static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir)
656 {
657 struct dentry *dentry = filp->f_path.dentry;
658 struct inode *inode = dentry->d_inode;
659 struct ctl_table_header *head = grab_header(inode);
660 struct ctl_table_header *h = NULL;
661 struct ctl_table *entry;
662 struct ctl_dir *ctl_dir;
663 unsigned long pos;
664 int ret = -EINVAL;
665
666 if (IS_ERR(head))
667 return PTR_ERR(head);
668
669 ctl_dir = container_of(head, struct ctl_dir, header);
670
671 ret = 0;
672 /* Avoid a switch here: arm builds fail with missing __cmpdi2 */
673 if (filp->f_pos == 0) {
674 if (filldir(dirent, ".", 1, filp->f_pos,
675 inode->i_ino, DT_DIR) < 0)
676 goto out;
677 filp->f_pos++;
678 }
679 if (filp->f_pos == 1) {
680 if (filldir(dirent, "..", 2, filp->f_pos,
681 parent_ino(dentry), DT_DIR) < 0)
682 goto out;
683 filp->f_pos++;
684 }
685 pos = 2;
686
687 for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) {
688 ret = scan(h, entry, &pos, filp, dirent, filldir);
689 if (ret) {
690 sysctl_head_finish(h);
691 break;
692 }
693 }
694 ret = 1;
695 out:
696 sysctl_head_finish(head);
697 return ret;
698 }
699
700 static int proc_sys_permission(struct inode *inode, int mask)
701 {
702 /*
703 * sysctl entries that are not writeable,
704 * are _NOT_ writeable, capabilities or not.
705 */
706 struct ctl_table_header *head;
707 struct ctl_table *table;
708 int error;
709
710 /* Executable files are not allowed under /proc/sys/ */
711 if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
712 return -EACCES;
713
714 head = grab_header(inode);
715 if (IS_ERR(head))
716 return PTR_ERR(head);
717
718 table = PROC_I(inode)->sysctl_entry;
719 if (!table) /* global root - r-xr-xr-x */
720 error = mask & MAY_WRITE ? -EACCES : 0;
721 else /* Use the permissions on the sysctl table entry */
722 error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK);
723
724 sysctl_head_finish(head);
725 return error;
726 }
727
728 static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr)
729 {
730 struct inode *inode = dentry->d_inode;
731 int error;
732
733 if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
734 return -EPERM;
735
736 error = inode_change_ok(inode, attr);
737 if (error)
738 return error;
739
740 setattr_copy(inode, attr);
741 mark_inode_dirty(inode);
742 return 0;
743 }
744
745 static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
746 {
747 struct inode *inode = dentry->d_inode;
748 struct ctl_table_header *head = grab_header(inode);
749 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
750
751 if (IS_ERR(head))
752 return PTR_ERR(head);
753
754 generic_fillattr(inode, stat);
755 if (table)
756 stat->mode = (stat->mode & S_IFMT) | table->mode;
757
758 sysctl_head_finish(head);
759 return 0;
760 }
761
762 static const struct file_operations proc_sys_file_operations = {
763 .open = proc_sys_open,
764 .poll = proc_sys_poll,
765 .read = proc_sys_read,
766 .write = proc_sys_write,
767 .llseek = default_llseek,
768 };
769
770 static const struct file_operations proc_sys_dir_file_operations = {
771 .read = generic_read_dir,
772 .readdir = proc_sys_readdir,
773 .llseek = generic_file_llseek,
774 };
775
776 static const struct inode_operations proc_sys_inode_operations = {
777 .permission = proc_sys_permission,
778 .setattr = proc_sys_setattr,
779 .getattr = proc_sys_getattr,
780 };
781
782 static const struct inode_operations proc_sys_dir_operations = {
783 .lookup = proc_sys_lookup,
784 .permission = proc_sys_permission,
785 .setattr = proc_sys_setattr,
786 .getattr = proc_sys_getattr,
787 };
788
789 static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags)
790 {
791 if (flags & LOOKUP_RCU)
792 return -ECHILD;
793 return !PROC_I(dentry->d_inode)->sysctl->unregistering;
794 }
795
796 static int proc_sys_delete(const struct dentry *dentry)
797 {
798 return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
799 }
800
801 static int sysctl_is_seen(struct ctl_table_header *p)
802 {
803 struct ctl_table_set *set = p->set;
804 int res;
805 spin_lock(&sysctl_lock);
806 if (p->unregistering)
807 res = 0;
808 else if (!set->is_seen)
809 res = 1;
810 else
811 res = set->is_seen(set);
812 spin_unlock(&sysctl_lock);
813 return res;
814 }
815
816 static int proc_sys_compare(const struct dentry *parent,
817 const struct inode *pinode,
818 const struct dentry *dentry, const struct inode *inode,
819 unsigned int len, const char *str, const struct qstr *name)
820 {
821 struct ctl_table_header *head;
822 /* Although proc doesn't have negative dentries, rcu-walk means
823 * that inode here can be NULL */
824 /* AV: can it, indeed? */
825 if (!inode)
826 return 1;
827 if (name->len != len)
828 return 1;
829 if (memcmp(name->name, str, len))
830 return 1;
831 head = rcu_dereference(PROC_I(inode)->sysctl);
832 return !head || !sysctl_is_seen(head);
833 }
834
835 static const struct dentry_operations proc_sys_dentry_operations = {
836 .d_revalidate = proc_sys_revalidate,
837 .d_delete = proc_sys_delete,
838 .d_compare = proc_sys_compare,
839 };
840
841 static struct ctl_dir *find_subdir(struct ctl_dir *dir,
842 const char *name, int namelen)
843 {
844 struct ctl_table_header *head;
845 struct ctl_table *entry;
846
847 entry = find_entry(&head, dir, name, namelen);
848 if (!entry)
849 return ERR_PTR(-ENOENT);
850 if (!S_ISDIR(entry->mode))
851 return ERR_PTR(-ENOTDIR);
852 return container_of(head, struct ctl_dir, header);
853 }
854
855 static struct ctl_dir *new_dir(struct ctl_table_set *set,
856 const char *name, int namelen)
857 {
858 struct ctl_table *table;
859 struct ctl_dir *new;
860 struct ctl_node *node;
861 char *new_name;
862
863 new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) +
864 sizeof(struct ctl_table)*2 + namelen + 1,
865 GFP_KERNEL);
866 if (!new)
867 return NULL;
868
869 node = (struct ctl_node *)(new + 1);
870 table = (struct ctl_table *)(node + 1);
871 new_name = (char *)(table + 2);
872 memcpy(new_name, name, namelen);
873 new_name[namelen] = '\0';
874 table[0].procname = new_name;
875 table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO;
876 init_header(&new->header, set->dir.header.root, set, node, table);
877
878 return new;
879 }
880
881 /**
882 * get_subdir - find or create a subdir with the specified name.
883 * @dir: Directory to create the subdirectory in
884 * @name: The name of the subdirectory to find or create
885 * @namelen: The length of name
886 *
887 * Takes a directory with an elevated reference count so we know that
888 * if we drop the lock the directory will not go away. Upon success
889 * the reference is moved from @dir to the returned subdirectory.
890 * Upon error an error code is returned and the reference on @dir is
891 * simply dropped.
892 */
893 static struct ctl_dir *get_subdir(struct ctl_dir *dir,
894 const char *name, int namelen)
895 {
896 struct ctl_table_set *set = dir->header.set;
897 struct ctl_dir *subdir, *new = NULL;
898 int err;
899
900 spin_lock(&sysctl_lock);
901 subdir = find_subdir(dir, name, namelen);
902 if (!IS_ERR(subdir))
903 goto found;
904 if (PTR_ERR(subdir) != -ENOENT)
905 goto failed;
906
907 spin_unlock(&sysctl_lock);
908 new = new_dir(set, name, namelen);
909 spin_lock(&sysctl_lock);
910 subdir = ERR_PTR(-ENOMEM);
911 if (!new)
912 goto failed;
913
914 /* Was the subdir added while we dropped the lock? */
915 subdir = find_subdir(dir, name, namelen);
916 if (!IS_ERR(subdir))
917 goto found;
918 if (PTR_ERR(subdir) != -ENOENT)
919 goto failed;
920
921 /* Nope. Use the our freshly made directory entry. */
922 err = insert_header(dir, &new->header);
923 subdir = ERR_PTR(err);
924 if (err)
925 goto failed;
926 subdir = new;
927 found:
928 subdir->header.nreg++;
929 failed:
930 if (unlikely(IS_ERR(subdir))) {
931 pr_err("sysctl could not get directory: ");
932 sysctl_print_dir(dir);
933 pr_cont("/%*.*s %ld\n",
934 namelen, namelen, name, PTR_ERR(subdir));
935 }
936 drop_sysctl_table(&dir->header);
937 if (new)
938 drop_sysctl_table(&new->header);
939 spin_unlock(&sysctl_lock);
940 return subdir;
941 }
942
943 static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir)
944 {
945 struct ctl_dir *parent;
946 const char *procname;
947 if (!dir->header.parent)
948 return &set->dir;
949 parent = xlate_dir(set, dir->header.parent);
950 if (IS_ERR(parent))
951 return parent;
952 procname = dir->header.ctl_table[0].procname;
953 return find_subdir(parent, procname, strlen(procname));
954 }
955
956 static int sysctl_follow_link(struct ctl_table_header **phead,
957 struct ctl_table **pentry, struct nsproxy *namespaces)
958 {
959 struct ctl_table_header *head;
960 struct ctl_table_root *root;
961 struct ctl_table_set *set;
962 struct ctl_table *entry;
963 struct ctl_dir *dir;
964 int ret;
965
966 ret = 0;
967 spin_lock(&sysctl_lock);
968 root = (*pentry)->data;
969 set = lookup_header_set(root, namespaces);
970 dir = xlate_dir(set, (*phead)->parent);
971 if (IS_ERR(dir))
972 ret = PTR_ERR(dir);
973 else {
974 const char *procname = (*pentry)->procname;
975 head = NULL;
976 entry = find_entry(&head, dir, procname, strlen(procname));
977 ret = -ENOENT;
978 if (entry && use_table(head)) {
979 unuse_table(*phead);
980 *phead = head;
981 *pentry = entry;
982 ret = 0;
983 }
984 }
985
986 spin_unlock(&sysctl_lock);
987 return ret;
988 }
989
990 static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...)
991 {
992 struct va_format vaf;
993 va_list args;
994
995 va_start(args, fmt);
996 vaf.fmt = fmt;
997 vaf.va = &args;
998
999 pr_err("sysctl table check failed: %s/%s %pV\n",
1000 path, table->procname, &vaf);
1001
1002 va_end(args);
1003 return -EINVAL;
1004 }
1005
1006 static int sysctl_check_table(const char *path, struct ctl_table *table)
1007 {
1008 int err = 0;
1009 for (; table->procname; table++) {
1010 if (table->child)
1011 err = sysctl_err(path, table, "Not a file");
1012
1013 if ((table->proc_handler == proc_dostring) ||
1014 (table->proc_handler == proc_dointvec) ||
1015 (table->proc_handler == proc_dointvec_minmax) ||
1016 (table->proc_handler == proc_dointvec_jiffies) ||
1017 (table->proc_handler == proc_dointvec_userhz_jiffies) ||
1018 (table->proc_handler == proc_dointvec_ms_jiffies) ||
1019 (table->proc_handler == proc_doulongvec_minmax) ||
1020 (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
1021 if (!table->data)
1022 err = sysctl_err(path, table, "No data");
1023 if (!table->maxlen)
1024 err = sysctl_err(path, table, "No maxlen");
1025 }
1026 if (!table->proc_handler)
1027 err = sysctl_err(path, table, "No proc_handler");
1028
1029 if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode)
1030 err = sysctl_err(path, table, "bogus .mode 0%o",
1031 table->mode);
1032 }
1033 return err;
1034 }
1035
1036 static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table,
1037 struct ctl_table_root *link_root)
1038 {
1039 struct ctl_table *link_table, *entry, *link;
1040 struct ctl_table_header *links;
1041 struct ctl_node *node;
1042 char *link_name;
1043 int nr_entries, name_bytes;
1044
1045 name_bytes = 0;
1046 nr_entries = 0;
1047 for (entry = table; entry->procname; entry++) {
1048 nr_entries++;
1049 name_bytes += strlen(entry->procname) + 1;
1050 }
1051
1052 links = kzalloc(sizeof(struct ctl_table_header) +
1053 sizeof(struct ctl_node)*nr_entries +
1054 sizeof(struct ctl_table)*(nr_entries + 1) +
1055 name_bytes,
1056 GFP_KERNEL);
1057
1058 if (!links)
1059 return NULL;
1060
1061 node = (struct ctl_node *)(links + 1);
1062 link_table = (struct ctl_table *)(node + nr_entries);
1063 link_name = (char *)&link_table[nr_entries + 1];
1064
1065 for (link = link_table, entry = table; entry->procname; link++, entry++) {
1066 int len = strlen(entry->procname) + 1;
1067 memcpy(link_name, entry->procname, len);
1068 link->procname = link_name;
1069 link->mode = S_IFLNK|S_IRWXUGO;
1070 link->data = link_root;
1071 link_name += len;
1072 }
1073 init_header(links, dir->header.root, dir->header.set, node, link_table);
1074 links->nreg = nr_entries;
1075
1076 return links;
1077 }
1078
1079 static bool get_links(struct ctl_dir *dir,
1080 struct ctl_table *table, struct ctl_table_root *link_root)
1081 {
1082 struct ctl_table_header *head;
1083 struct ctl_table *entry, *link;
1084
1085 /* Are there links available for every entry in table? */
1086 for (entry = table; entry->procname; entry++) {
1087 const char *procname = entry->procname;
1088 link = find_entry(&head, dir, procname, strlen(procname));
1089 if (!link)
1090 return false;
1091 if (S_ISDIR(link->mode) && S_ISDIR(entry->mode))
1092 continue;
1093 if (S_ISLNK(link->mode) && (link->data == link_root))
1094 continue;
1095 return false;
1096 }
1097
1098 /* The checks passed. Increase the registration count on the links */
1099 for (entry = table; entry->procname; entry++) {
1100 const char *procname = entry->procname;
1101 link = find_entry(&head, dir, procname, strlen(procname));
1102 head->nreg++;
1103 }
1104 return true;
1105 }
1106
1107 static int insert_links(struct ctl_table_header *head)
1108 {
1109 struct ctl_table_set *root_set = &sysctl_table_root.default_set;
1110 struct ctl_dir *core_parent = NULL;
1111 struct ctl_table_header *links;
1112 int err;
1113
1114 if (head->set == root_set)
1115 return 0;
1116
1117 core_parent = xlate_dir(root_set, head->parent);
1118 if (IS_ERR(core_parent))
1119 return 0;
1120
1121 if (get_links(core_parent, head->ctl_table, head->root))
1122 return 0;
1123
1124 core_parent->header.nreg++;
1125 spin_unlock(&sysctl_lock);
1126
1127 links = new_links(core_parent, head->ctl_table, head->root);
1128
1129 spin_lock(&sysctl_lock);
1130 err = -ENOMEM;
1131 if (!links)
1132 goto out;
1133
1134 err = 0;
1135 if (get_links(core_parent, head->ctl_table, head->root)) {
1136 kfree(links);
1137 goto out;
1138 }
1139
1140 err = insert_header(core_parent, links);
1141 if (err)
1142 kfree(links);
1143 out:
1144 drop_sysctl_table(&core_parent->header);
1145 return err;
1146 }
1147
1148 /**
1149 * __register_sysctl_table - register a leaf sysctl table
1150 * @set: Sysctl tree to register on
1151 * @path: The path to the directory the sysctl table is in.
1152 * @table: the top-level table structure
1153 *
1154 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1155 * array. A completely 0 filled entry terminates the table.
1156 *
1157 * The members of the &struct ctl_table structure are used as follows:
1158 *
1159 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1160 * enter a sysctl file
1161 *
1162 * data - a pointer to data for use by proc_handler
1163 *
1164 * maxlen - the maximum size in bytes of the data
1165 *
1166 * mode - the file permissions for the /proc/sys file
1167 *
1168 * child - must be %NULL.
1169 *
1170 * proc_handler - the text handler routine (described below)
1171 *
1172 * extra1, extra2 - extra pointers usable by the proc handler routines
1173 *
1174 * Leaf nodes in the sysctl tree will be represented by a single file
1175 * under /proc; non-leaf nodes will be represented by directories.
1176 *
1177 * There must be a proc_handler routine for any terminal nodes.
1178 * Several default handlers are available to cover common cases -
1179 *
1180 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1181 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1182 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1183 *
1184 * It is the handler's job to read the input buffer from user memory
1185 * and process it. The handler should return 0 on success.
1186 *
1187 * This routine returns %NULL on a failure to register, and a pointer
1188 * to the table header on success.
1189 */
1190 struct ctl_table_header *__register_sysctl_table(
1191 struct ctl_table_set *set,
1192 const char *path, struct ctl_table *table)
1193 {
1194 struct ctl_table_root *root = set->dir.header.root;
1195 struct ctl_table_header *header;
1196 const char *name, *nextname;
1197 struct ctl_dir *dir;
1198 struct ctl_table *entry;
1199 struct ctl_node *node;
1200 int nr_entries = 0;
1201
1202 for (entry = table; entry->procname; entry++)
1203 nr_entries++;
1204
1205 header = kzalloc(sizeof(struct ctl_table_header) +
1206 sizeof(struct ctl_node)*nr_entries, GFP_KERNEL);
1207 if (!header)
1208 return NULL;
1209
1210 node = (struct ctl_node *)(header + 1);
1211 init_header(header, root, set, node, table);
1212 if (sysctl_check_table(path, table))
1213 goto fail;
1214
1215 spin_lock(&sysctl_lock);
1216 dir = &set->dir;
1217 /* Reference moved down the diretory tree get_subdir */
1218 dir->header.nreg++;
1219 spin_unlock(&sysctl_lock);
1220
1221 /* Find the directory for the ctl_table */
1222 for (name = path; name; name = nextname) {
1223 int namelen;
1224 nextname = strchr(name, '/');
1225 if (nextname) {
1226 namelen = nextname - name;
1227 nextname++;
1228 } else {
1229 namelen = strlen(name);
1230 }
1231 if (namelen == 0)
1232 continue;
1233
1234 dir = get_subdir(dir, name, namelen);
1235 if (IS_ERR(dir))
1236 goto fail;
1237 }
1238
1239 spin_lock(&sysctl_lock);
1240 if (insert_header(dir, header))
1241 goto fail_put_dir_locked;
1242
1243 drop_sysctl_table(&dir->header);
1244 spin_unlock(&sysctl_lock);
1245
1246 return header;
1247
1248 fail_put_dir_locked:
1249 drop_sysctl_table(&dir->header);
1250 spin_unlock(&sysctl_lock);
1251 fail:
1252 kfree(header);
1253 dump_stack();
1254 return NULL;
1255 }
1256
1257 /**
1258 * register_sysctl - register a sysctl table
1259 * @path: The path to the directory the sysctl table is in.
1260 * @table: the table structure
1261 *
1262 * Register a sysctl table. @table should be a filled in ctl_table
1263 * array. A completely 0 filled entry terminates the table.
1264 *
1265 * See __register_sysctl_table for more details.
1266 */
1267 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
1268 {
1269 return __register_sysctl_table(&sysctl_table_root.default_set,
1270 path, table);
1271 }
1272 EXPORT_SYMBOL(register_sysctl);
1273
1274 static char *append_path(const char *path, char *pos, const char *name)
1275 {
1276 int namelen;
1277 namelen = strlen(name);
1278 if (((pos - path) + namelen + 2) >= PATH_MAX)
1279 return NULL;
1280 memcpy(pos, name, namelen);
1281 pos[namelen] = '/';
1282 pos[namelen + 1] = '\0';
1283 pos += namelen + 1;
1284 return pos;
1285 }
1286
1287 static int count_subheaders(struct ctl_table *table)
1288 {
1289 int has_files = 0;
1290 int nr_subheaders = 0;
1291 struct ctl_table *entry;
1292
1293 /* special case: no directory and empty directory */
1294 if (!table || !table->procname)
1295 return 1;
1296
1297 for (entry = table; entry->procname; entry++) {
1298 if (entry->child)
1299 nr_subheaders += count_subheaders(entry->child);
1300 else
1301 has_files = 1;
1302 }
1303 return nr_subheaders + has_files;
1304 }
1305
1306 static int register_leaf_sysctl_tables(const char *path, char *pos,
1307 struct ctl_table_header ***subheader, struct ctl_table_set *set,
1308 struct ctl_table *table)
1309 {
1310 struct ctl_table *ctl_table_arg = NULL;
1311 struct ctl_table *entry, *files;
1312 int nr_files = 0;
1313 int nr_dirs = 0;
1314 int err = -ENOMEM;
1315
1316 for (entry = table; entry->procname; entry++) {
1317 if (entry->child)
1318 nr_dirs++;
1319 else
1320 nr_files++;
1321 }
1322
1323 files = table;
1324 /* If there are mixed files and directories we need a new table */
1325 if (nr_dirs && nr_files) {
1326 struct ctl_table *new;
1327 files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1),
1328 GFP_KERNEL);
1329 if (!files)
1330 goto out;
1331
1332 ctl_table_arg = files;
1333 for (new = files, entry = table; entry->procname; entry++) {
1334 if (entry->child)
1335 continue;
1336 *new = *entry;
1337 new++;
1338 }
1339 }
1340
1341 /* Register everything except a directory full of subdirectories */
1342 if (nr_files || !nr_dirs) {
1343 struct ctl_table_header *header;
1344 header = __register_sysctl_table(set, path, files);
1345 if (!header) {
1346 kfree(ctl_table_arg);
1347 goto out;
1348 }
1349
1350 /* Remember if we need to free the file table */
1351 header->ctl_table_arg = ctl_table_arg;
1352 **subheader = header;
1353 (*subheader)++;
1354 }
1355
1356 /* Recurse into the subdirectories. */
1357 for (entry = table; entry->procname; entry++) {
1358 char *child_pos;
1359
1360 if (!entry->child)
1361 continue;
1362
1363 err = -ENAMETOOLONG;
1364 child_pos = append_path(path, pos, entry->procname);
1365 if (!child_pos)
1366 goto out;
1367
1368 err = register_leaf_sysctl_tables(path, child_pos, subheader,
1369 set, entry->child);
1370 pos[0] = '\0';
1371 if (err)
1372 goto out;
1373 }
1374 err = 0;
1375 out:
1376 /* On failure our caller will unregister all registered subheaders */
1377 return err;
1378 }
1379
1380 /**
1381 * __register_sysctl_paths - register a sysctl table hierarchy
1382 * @set: Sysctl tree to register on
1383 * @path: The path to the directory the sysctl table is in.
1384 * @table: the top-level table structure
1385 *
1386 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1387 * array. A completely 0 filled entry terminates the table.
1388 *
1389 * See __register_sysctl_table for more details.
1390 */
1391 struct ctl_table_header *__register_sysctl_paths(
1392 struct ctl_table_set *set,
1393 const struct ctl_path *path, struct ctl_table *table)
1394 {
1395 struct ctl_table *ctl_table_arg = table;
1396 int nr_subheaders = count_subheaders(table);
1397 struct ctl_table_header *header = NULL, **subheaders, **subheader;
1398 const struct ctl_path *component;
1399 char *new_path, *pos;
1400
1401 pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL);
1402 if (!new_path)
1403 return NULL;
1404
1405 pos[0] = '\0';
1406 for (component = path; component->procname; component++) {
1407 pos = append_path(new_path, pos, component->procname);
1408 if (!pos)
1409 goto out;
1410 }
1411 while (table->procname && table->child && !table[1].procname) {
1412 pos = append_path(new_path, pos, table->procname);
1413 if (!pos)
1414 goto out;
1415 table = table->child;
1416 }
1417 if (nr_subheaders == 1) {
1418 header = __register_sysctl_table(set, new_path, table);
1419 if (header)
1420 header->ctl_table_arg = ctl_table_arg;
1421 } else {
1422 header = kzalloc(sizeof(*header) +
1423 sizeof(*subheaders)*nr_subheaders, GFP_KERNEL);
1424 if (!header)
1425 goto out;
1426
1427 subheaders = (struct ctl_table_header **) (header + 1);
1428 subheader = subheaders;
1429 header->ctl_table_arg = ctl_table_arg;
1430
1431 if (register_leaf_sysctl_tables(new_path, pos, &subheader,
1432 set, table))
1433 goto err_register_leaves;
1434 }
1435
1436 out:
1437 kfree(new_path);
1438 return header;
1439
1440 err_register_leaves:
1441 while (subheader > subheaders) {
1442 struct ctl_table_header *subh = *(--subheader);
1443 struct ctl_table *table = subh->ctl_table_arg;
1444 unregister_sysctl_table(subh);
1445 kfree(table);
1446 }
1447 kfree(header);
1448 header = NULL;
1449 goto out;
1450 }
1451
1452 /**
1453 * register_sysctl_table_path - register a sysctl table hierarchy
1454 * @path: The path to the directory the sysctl table is in.
1455 * @table: the top-level table structure
1456 *
1457 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1458 * array. A completely 0 filled entry terminates the table.
1459 *
1460 * See __register_sysctl_paths for more details.
1461 */
1462 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1463 struct ctl_table *table)
1464 {
1465 return __register_sysctl_paths(&sysctl_table_root.default_set,
1466 path, table);
1467 }
1468 EXPORT_SYMBOL(register_sysctl_paths);
1469
1470 /**
1471 * register_sysctl_table - register a sysctl table hierarchy
1472 * @table: the top-level table structure
1473 *
1474 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1475 * array. A completely 0 filled entry terminates the table.
1476 *
1477 * See register_sysctl_paths for more details.
1478 */
1479 struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
1480 {
1481 static const struct ctl_path null_path[] = { {} };
1482
1483 return register_sysctl_paths(null_path, table);
1484 }
1485 EXPORT_SYMBOL(register_sysctl_table);
1486
1487 static void put_links(struct ctl_table_header *header)
1488 {
1489 struct ctl_table_set *root_set = &sysctl_table_root.default_set;
1490 struct ctl_table_root *root = header->root;
1491 struct ctl_dir *parent = header->parent;
1492 struct ctl_dir *core_parent;
1493 struct ctl_table *entry;
1494
1495 if (header->set == root_set)
1496 return;
1497
1498 core_parent = xlate_dir(root_set, parent);
1499 if (IS_ERR(core_parent))
1500 return;
1501
1502 for (entry = header->ctl_table; entry->procname; entry++) {
1503 struct ctl_table_header *link_head;
1504 struct ctl_table *link;
1505 const char *name = entry->procname;
1506
1507 link = find_entry(&link_head, core_parent, name, strlen(name));
1508 if (link &&
1509 ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) ||
1510 (S_ISLNK(link->mode) && (link->data == root)))) {
1511 drop_sysctl_table(link_head);
1512 }
1513 else {
1514 pr_err("sysctl link missing during unregister: ");
1515 sysctl_print_dir(parent);
1516 pr_cont("/%s\n", name);
1517 }
1518 }
1519 }
1520
1521 static void drop_sysctl_table(struct ctl_table_header *header)
1522 {
1523 struct ctl_dir *parent = header->parent;
1524
1525 if (--header->nreg)
1526 return;
1527
1528 put_links(header);
1529 start_unregistering(header);
1530 if (!--header->count)
1531 kfree_rcu(header, rcu);
1532
1533 if (parent)
1534 drop_sysctl_table(&parent->header);
1535 }
1536
1537 /**
1538 * unregister_sysctl_table - unregister a sysctl table hierarchy
1539 * @header: the header returned from register_sysctl_table
1540 *
1541 * Unregisters the sysctl table and all children. proc entries may not
1542 * actually be removed until they are no longer used by anyone.
1543 */
1544 void unregister_sysctl_table(struct ctl_table_header * header)
1545 {
1546 int nr_subheaders;
1547 might_sleep();
1548
1549 if (header == NULL)
1550 return;
1551
1552 nr_subheaders = count_subheaders(header->ctl_table_arg);
1553 if (unlikely(nr_subheaders > 1)) {
1554 struct ctl_table_header **subheaders;
1555 int i;
1556
1557 subheaders = (struct ctl_table_header **)(header + 1);
1558 for (i = nr_subheaders -1; i >= 0; i--) {
1559 struct ctl_table_header *subh = subheaders[i];
1560 struct ctl_table *table = subh->ctl_table_arg;
1561 unregister_sysctl_table(subh);
1562 kfree(table);
1563 }
1564 kfree(header);
1565 return;
1566 }
1567
1568 spin_lock(&sysctl_lock);
1569 drop_sysctl_table(header);
1570 spin_unlock(&sysctl_lock);
1571 }
1572 EXPORT_SYMBOL(unregister_sysctl_table);
1573
1574 void setup_sysctl_set(struct ctl_table_set *set,
1575 struct ctl_table_root *root,
1576 int (*is_seen)(struct ctl_table_set *))
1577 {
1578 memset(set, 0, sizeof(*set));
1579 set->is_seen = is_seen;
1580 init_header(&set->dir.header, root, set, NULL, root_table);
1581 }
1582
1583 void retire_sysctl_set(struct ctl_table_set *set)
1584 {
1585 WARN_ON(!RB_EMPTY_ROOT(&set->dir.root));
1586 }
1587
1588 int __init proc_sys_init(void)
1589 {
1590 struct proc_dir_entry *proc_sys_root;
1591
1592 proc_sys_root = proc_mkdir("sys", NULL);
1593 proc_sys_root->proc_iops = &proc_sys_dir_operations;
1594 proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
1595 proc_sys_root->nlink = 0;
1596
1597 return sysctl_init();
1598 }
kernel source for telekom puls (alcatel/mediatek)