blob: 9b91deeeb56c5932210b2cfa1fc99fe2a3dbe75d [file] [log] [blame]
Eric W. Biederman77b14db2007-02-14 00:34:12 -08001/*
2 * /proc/sys support
3 */
Alexey Dobriyan1e0edd32008-10-17 05:07:44 +04004#include <linux/init.h>
Eric W. Biederman77b14db2007-02-14 00:34:12 -08005#include <linux/sysctl.h>
Lucas De Marchif1ecf062011-11-02 13:39:22 -07006#include <linux/poll.h>
Eric W. Biederman77b14db2007-02-14 00:34:12 -08007#include <linux/proc_fs.h>
8#include <linux/security.h>
Nick Piggin34286d62011-01-07 17:49:57 +11009#include <linux/namei.h>
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -080010#include <linux/module.h>
Eric W. Biederman77b14db2007-02-14 00:34:12 -080011#include "internal.h"
12
Al Virod72f71e2009-02-20 05:58:47 +000013static const struct dentry_operations proc_sys_dentry_operations;
Eric W. Biederman77b14db2007-02-14 00:34:12 -080014static const struct file_operations proc_sys_file_operations;
Jan Engelhardt03a44822008-02-08 04:21:19 -080015static const struct inode_operations proc_sys_inode_operations;
Al Viro9043476f2008-07-15 08:54:06 -040016static const struct file_operations proc_sys_dir_file_operations;
17static const struct inode_operations proc_sys_dir_operations;
Eric W. Biederman77b14db2007-02-14 00:34:12 -080018
Lucas De Marchif1ecf062011-11-02 13:39:22 -070019void 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
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -080028static struct ctl_table root_table[1];
29static struct ctl_table_root sysctl_table_root;
30static struct ctl_table_header root_table_header = {
31 {{.count = 1,
32 .ctl_table = root_table,
33 .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},
34 .root = &sysctl_table_root,
35 .set = &sysctl_table_root.default_set,
36};
37static struct ctl_table_root sysctl_table_root = {
38 .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
39 .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
40};
41
42static DEFINE_SPINLOCK(sysctl_lock);
43
44/* called under sysctl_lock */
45static int use_table(struct ctl_table_header *p)
46{
47 if (unlikely(p->unregistering))
48 return 0;
49 p->used++;
50 return 1;
51}
52
53/* called under sysctl_lock */
54static void unuse_table(struct ctl_table_header *p)
55{
56 if (!--p->used)
57 if (unlikely(p->unregistering))
58 complete(p->unregistering);
59}
60
61/* called under sysctl_lock, will reacquire if has to wait */
62static void start_unregistering(struct ctl_table_header *p)
63{
64 /*
65 * if p->used is 0, nobody will ever touch that entry again;
66 * we'll eliminate all paths to it before dropping sysctl_lock
67 */
68 if (unlikely(p->used)) {
69 struct completion wait;
70 init_completion(&wait);
71 p->unregistering = &wait;
72 spin_unlock(&sysctl_lock);
73 wait_for_completion(&wait);
74 spin_lock(&sysctl_lock);
75 } else {
76 /* anything non-NULL; we'll never dereference it */
77 p->unregistering = ERR_PTR(-EINVAL);
78 }
79 /*
80 * do not remove from the list until nobody holds it; walking the
81 * list in do_sysctl() relies on that.
82 */
83 list_del_init(&p->ctl_entry);
84}
85
86static void sysctl_head_get(struct ctl_table_header *head)
87{
88 spin_lock(&sysctl_lock);
89 head->count++;
90 spin_unlock(&sysctl_lock);
91}
92
93void sysctl_head_put(struct ctl_table_header *head)
94{
95 spin_lock(&sysctl_lock);
96 if (!--head->count)
97 kfree_rcu(head, rcu);
98 spin_unlock(&sysctl_lock);
99}
100
101static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
102{
103 if (!head)
104 BUG();
105 spin_lock(&sysctl_lock);
106 if (!use_table(head))
107 head = ERR_PTR(-ENOENT);
108 spin_unlock(&sysctl_lock);
109 return head;
110}
111
112static void sysctl_head_finish(struct ctl_table_header *head)
113{
114 if (!head)
115 return;
116 spin_lock(&sysctl_lock);
117 unuse_table(head);
118 spin_unlock(&sysctl_lock);
119}
120
121static struct ctl_table_set *
122lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
123{
124 struct ctl_table_set *set = &root->default_set;
125 if (root->lookup)
126 set = root->lookup(root, namespaces);
127 return set;
128}
129
130static struct list_head *
131lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
132{
133 struct ctl_table_set *set = lookup_header_set(root, namespaces);
134 return &set->list;
135}
136
137static struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
138 struct ctl_table_header *prev)
139{
140 struct ctl_table_root *root;
141 struct list_head *header_list;
142 struct ctl_table_header *head;
143 struct list_head *tmp;
144
145 spin_lock(&sysctl_lock);
146 if (prev) {
147 head = prev;
148 tmp = &prev->ctl_entry;
149 unuse_table(prev);
150 goto next;
151 }
152 tmp = &root_table_header.ctl_entry;
153 for (;;) {
154 head = list_entry(tmp, struct ctl_table_header, ctl_entry);
155
156 if (!use_table(head))
157 goto next;
158 spin_unlock(&sysctl_lock);
159 return head;
160 next:
161 root = head->root;
162 tmp = tmp->next;
163 header_list = lookup_header_list(root, namespaces);
164 if (tmp != header_list)
165 continue;
166
167 do {
168 root = list_entry(root->root_list.next,
169 struct ctl_table_root, root_list);
170 if (root == &sysctl_table_root)
171 goto out;
172 header_list = lookup_header_list(root, namespaces);
173 } while (list_empty(header_list));
174 tmp = header_list->next;
175 }
176out:
177 spin_unlock(&sysctl_lock);
178 return NULL;
179}
180
181static struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
182{
183 return __sysctl_head_next(current->nsproxy, prev);
184}
185
186void register_sysctl_root(struct ctl_table_root *root)
187{
188 spin_lock(&sysctl_lock);
189 list_add_tail(&root->root_list, &sysctl_table_root.root_list);
190 spin_unlock(&sysctl_lock);
191}
192
193/*
194 * sysctl_perm does NOT grant the superuser all rights automatically, because
195 * some sysctl variables are readonly even to root.
196 */
197
198static int test_perm(int mode, int op)
199{
200 if (!current_euid())
201 mode >>= 6;
202 else if (in_egroup_p(0))
203 mode >>= 3;
204 if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
205 return 0;
206 return -EACCES;
207}
208
209static int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
210{
211 int mode;
212
213 if (root->permissions)
214 mode = root->permissions(root, current->nsproxy, table);
215 else
216 mode = table->mode;
217
218 return test_perm(mode, op);
219}
220
221static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
222{
223 for (; table->procname; table++) {
224 table->parent = parent;
225 if (table->child)
226 sysctl_set_parent(table, table->child);
227 }
228}
229
230
Al Viro9043476f2008-07-15 08:54:06 -0400231static struct inode *proc_sys_make_inode(struct super_block *sb,
232 struct ctl_table_header *head, struct ctl_table *table)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800233{
234 struct inode *inode;
Al Viro9043476f2008-07-15 08:54:06 -0400235 struct proc_inode *ei;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800236
Al Viro9043476f2008-07-15 08:54:06 -0400237 inode = new_inode(sb);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800238 if (!inode)
239 goto out;
240
Christoph Hellwig85fe4022010-10-23 11:19:54 -0400241 inode->i_ino = get_next_ino();
242
Al Viro9043476f2008-07-15 08:54:06 -0400243 sysctl_head_get(head);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800244 ei = PROC_I(inode);
Al Viro9043476f2008-07-15 08:54:06 -0400245 ei->sysctl = head;
246 ei->sysctl_entry = table;
247
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800248 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
Al Viro9043476f2008-07-15 08:54:06 -0400249 inode->i_mode = table->mode;
250 if (!table->child) {
251 inode->i_mode |= S_IFREG;
252 inode->i_op = &proc_sys_inode_operations;
253 inode->i_fop = &proc_sys_file_operations;
254 } else {
255 inode->i_mode |= S_IFDIR;
Al Viro9043476f2008-07-15 08:54:06 -0400256 inode->i_op = &proc_sys_dir_operations;
257 inode->i_fop = &proc_sys_dir_file_operations;
258 }
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800259out:
260 return inode;
261}
262
Al Viro9043476f2008-07-15 08:54:06 -0400263static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800264{
Eric W. Biederman2315ffa2009-04-03 03:18:02 -0700265 for ( ; p->procname; p++) {
Lucas De Marchi36885d72011-06-10 02:36:05 -0300266 if (strlen(p->procname) != name->len)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800267 continue;
268
Lucas De Marchi36885d72011-06-10 02:36:05 -0300269 if (memcmp(p->procname, name->name, name->len) != 0)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800270 continue;
271
272 /* I have a match */
Al Viro9043476f2008-07-15 08:54:06 -0400273 return p;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800274 }
275 return NULL;
276}
277
Adrian Bunk81324362008-10-03 00:33:54 +0400278static struct ctl_table_header *grab_header(struct inode *inode)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800279{
Al Viro9043476f2008-07-15 08:54:06 -0400280 if (PROC_I(inode)->sysctl)
281 return sysctl_head_grab(PROC_I(inode)->sysctl);
282 else
283 return sysctl_head_next(NULL);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800284}
285
286static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
287 struct nameidata *nd)
288{
Al Viro9043476f2008-07-15 08:54:06 -0400289 struct ctl_table_header *head = grab_header(dir);
290 struct ctl_table *table = PROC_I(dir)->sysctl_entry;
291 struct ctl_table_header *h = NULL;
292 struct qstr *name = &dentry->d_name;
293 struct ctl_table *p;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800294 struct inode *inode;
Al Viro9043476f2008-07-15 08:54:06 -0400295 struct dentry *err = ERR_PTR(-ENOENT);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800296
Al Viro9043476f2008-07-15 08:54:06 -0400297 if (IS_ERR(head))
298 return ERR_CAST(head);
299
300 if (table && !table->child) {
301 WARN_ON(1);
302 goto out;
303 }
304
305 table = table ? table->child : head->ctl_table;
306
307 p = find_in_table(table, name);
308 if (!p) {
309 for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
310 if (h->attached_to != table)
311 continue;
312 p = find_in_table(h->attached_by, name);
313 if (p)
314 break;
315 }
316 }
317
318 if (!p)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800319 goto out;
320
321 err = ERR_PTR(-ENOMEM);
Al Viro9043476f2008-07-15 08:54:06 -0400322 inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
323 if (h)
324 sysctl_head_finish(h);
325
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800326 if (!inode)
327 goto out;
328
329 err = NULL;
Nick Pigginfb045ad2011-01-07 17:49:55 +1100330 d_set_d_op(dentry, &proc_sys_dentry_operations);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800331 d_add(dentry, inode);
332
333out:
334 sysctl_head_finish(head);
335 return err;
336}
337
Pavel Emelyanov7708bfb2008-04-29 01:02:40 -0700338static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
339 size_t count, loff_t *ppos, int write)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800340{
Al Viro9043476f2008-07-15 08:54:06 -0400341 struct inode *inode = filp->f_path.dentry->d_inode;
342 struct ctl_table_header *head = grab_header(inode);
343 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
David Howells2a2da532007-10-25 15:27:40 +0100344 ssize_t error;
345 size_t res;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800346
Al Viro9043476f2008-07-15 08:54:06 -0400347 if (IS_ERR(head))
348 return PTR_ERR(head);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800349
350 /*
351 * At this point we know that the sysctl was not unregistered
352 * and won't be until we finish.
353 */
354 error = -EPERM;
Pavel Emelyanovd7321cd2008-04-29 01:02:44 -0700355 if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ))
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800356 goto out;
357
Al Viro9043476f2008-07-15 08:54:06 -0400358 /* if that can happen at all, it should be -EINVAL, not -EISDIR */
359 error = -EINVAL;
360 if (!table->proc_handler)
361 goto out;
362
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800363 /* careful: calling conventions are nasty here */
364 res = count;
Alexey Dobriyan8d65af72009-09-23 15:57:19 -0700365 error = table->proc_handler(table, write, buf, &res, ppos);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800366 if (!error)
367 error = res;
368out:
369 sysctl_head_finish(head);
370
371 return error;
372}
373
Pavel Emelyanov7708bfb2008-04-29 01:02:40 -0700374static ssize_t proc_sys_read(struct file *filp, char __user *buf,
375 size_t count, loff_t *ppos)
376{
377 return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
378}
379
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800380static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
381 size_t count, loff_t *ppos)
382{
Pavel Emelyanov7708bfb2008-04-29 01:02:40 -0700383 return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800384}
385
Lucas De Marchif1ecf062011-11-02 13:39:22 -0700386static int proc_sys_open(struct inode *inode, struct file *filp)
387{
388 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
389
390 if (table->poll)
391 filp->private_data = proc_sys_poll_event(table->poll);
392
393 return 0;
394}
395
396static unsigned int proc_sys_poll(struct file *filp, poll_table *wait)
397{
398 struct inode *inode = filp->f_path.dentry->d_inode;
399 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
400 unsigned long event = (unsigned long)filp->private_data;
401 unsigned int ret = DEFAULT_POLLMASK;
402
403 if (!table->proc_handler)
404 goto out;
405
406 if (!table->poll)
407 goto out;
408
409 poll_wait(filp, &table->poll->wait, wait);
410
411 if (event != atomic_read(&table->poll->event)) {
412 filp->private_data = proc_sys_poll_event(table->poll);
413 ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI;
414 }
415
416out:
417 return ret;
418}
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800419
420static int proc_sys_fill_cache(struct file *filp, void *dirent,
Al Viro9043476f2008-07-15 08:54:06 -0400421 filldir_t filldir,
422 struct ctl_table_header *head,
423 struct ctl_table *table)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800424{
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800425 struct dentry *child, *dir = filp->f_path.dentry;
426 struct inode *inode;
427 struct qstr qname;
428 ino_t ino = 0;
429 unsigned type = DT_UNKNOWN;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800430
431 qname.name = table->procname;
432 qname.len = strlen(table->procname);
433 qname.hash = full_name_hash(qname.name, qname.len);
434
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800435 child = d_lookup(dir, &qname);
436 if (!child) {
Al Viro9043476f2008-07-15 08:54:06 -0400437 child = d_alloc(dir, &qname);
438 if (child) {
439 inode = proc_sys_make_inode(dir->d_sb, head, table);
440 if (!inode) {
441 dput(child);
442 return -ENOMEM;
443 } else {
Nick Pigginfb045ad2011-01-07 17:49:55 +1100444 d_set_d_op(child, &proc_sys_dentry_operations);
Al Viro9043476f2008-07-15 08:54:06 -0400445 d_add(child, inode);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800446 }
Al Viro9043476f2008-07-15 08:54:06 -0400447 } else {
448 return -ENOMEM;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800449 }
450 }
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800451 inode = child->d_inode;
Al Viro9043476f2008-07-15 08:54:06 -0400452 ino = inode->i_ino;
453 type = inode->i_mode >> 12;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800454 dput(child);
Al Viro9043476f2008-07-15 08:54:06 -0400455 return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
456}
457
458static int scan(struct ctl_table_header *head, ctl_table *table,
459 unsigned long *pos, struct file *file,
460 void *dirent, filldir_t filldir)
461{
462
Eric W. Biederman2315ffa2009-04-03 03:18:02 -0700463 for (; table->procname; table++, (*pos)++) {
Al Viro9043476f2008-07-15 08:54:06 -0400464 int res;
465
Al Viro9043476f2008-07-15 08:54:06 -0400466 if (*pos < file->f_pos)
467 continue;
468
469 res = proc_sys_fill_cache(file, dirent, filldir, head, table);
470 if (res)
471 return res;
472
473 file->f_pos = *pos + 1;
474 }
475 return 0;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800476}
477
478static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir)
479{
Al Viro9043476f2008-07-15 08:54:06 -0400480 struct dentry *dentry = filp->f_path.dentry;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800481 struct inode *inode = dentry->d_inode;
Al Viro9043476f2008-07-15 08:54:06 -0400482 struct ctl_table_header *head = grab_header(inode);
483 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
484 struct ctl_table_header *h = NULL;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800485 unsigned long pos;
Al Viro9043476f2008-07-15 08:54:06 -0400486 int ret = -EINVAL;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800487
Al Viro9043476f2008-07-15 08:54:06 -0400488 if (IS_ERR(head))
489 return PTR_ERR(head);
490
491 if (table && !table->child) {
492 WARN_ON(1);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800493 goto out;
Al Viro9043476f2008-07-15 08:54:06 -0400494 }
495
496 table = table ? table->child : head->ctl_table;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800497
498 ret = 0;
499 /* Avoid a switch here: arm builds fail with missing __cmpdi2 */
500 if (filp->f_pos == 0) {
501 if (filldir(dirent, ".", 1, filp->f_pos,
502 inode->i_ino, DT_DIR) < 0)
503 goto out;
504 filp->f_pos++;
505 }
506 if (filp->f_pos == 1) {
507 if (filldir(dirent, "..", 2, filp->f_pos,
508 parent_ino(dentry), DT_DIR) < 0)
509 goto out;
510 filp->f_pos++;
511 }
512 pos = 2;
513
Al Viro9043476f2008-07-15 08:54:06 -0400514 ret = scan(head, table, &pos, filp, dirent, filldir);
515 if (ret)
516 goto out;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800517
Al Viro9043476f2008-07-15 08:54:06 -0400518 for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
519 if (h->attached_to != table)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800520 continue;
Al Viro9043476f2008-07-15 08:54:06 -0400521 ret = scan(h, h->attached_by, &pos, filp, dirent, filldir);
522 if (ret) {
523 sysctl_head_finish(h);
524 break;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800525 }
526 }
527 ret = 1;
528out:
529 sysctl_head_finish(head);
530 return ret;
531}
532
Al Viro10556cb2011-06-20 19:28:19 -0400533static int proc_sys_permission(struct inode *inode, int mask)
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800534{
535 /*
536 * sysctl entries that are not writeable,
537 * are _NOT_ writeable, capabilities or not.
538 */
Miklos Szeredif696a362008-07-31 13:41:58 +0200539 struct ctl_table_header *head;
540 struct ctl_table *table;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800541 int error;
542
Miklos Szeredif696a362008-07-31 13:41:58 +0200543 /* Executable files are not allowed under /proc/sys/ */
544 if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
545 return -EACCES;
546
547 head = grab_header(inode);
Al Viro9043476f2008-07-15 08:54:06 -0400548 if (IS_ERR(head))
549 return PTR_ERR(head);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800550
Miklos Szeredif696a362008-07-31 13:41:58 +0200551 table = PROC_I(inode)->sysctl_entry;
Al Viro9043476f2008-07-15 08:54:06 -0400552 if (!table) /* global root - r-xr-xr-x */
553 error = mask & MAY_WRITE ? -EACCES : 0;
554 else /* Use the permissions on the sysctl table entry */
Al Viro1fc0f782011-06-20 18:59:02 -0400555 error = sysctl_perm(head->root, table, mask & ~MAY_NOT_BLOCK);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800556
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800557 sysctl_head_finish(head);
558 return error;
559}
560
561static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr)
562{
563 struct inode *inode = dentry->d_inode;
564 int error;
565
566 if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
567 return -EPERM;
568
569 error = inode_change_ok(inode, attr);
Christoph Hellwig10257742010-06-04 11:30:02 +0200570 if (error)
571 return error;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800572
Christoph Hellwig10257742010-06-04 11:30:02 +0200573 if ((attr->ia_valid & ATTR_SIZE) &&
574 attr->ia_size != i_size_read(inode)) {
575 error = vmtruncate(inode, attr->ia_size);
576 if (error)
577 return error;
578 }
579
580 setattr_copy(inode, attr);
581 mark_inode_dirty(inode);
582 return 0;
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800583}
584
Al Viro9043476f2008-07-15 08:54:06 -0400585static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
586{
587 struct inode *inode = dentry->d_inode;
588 struct ctl_table_header *head = grab_header(inode);
589 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
590
591 if (IS_ERR(head))
592 return PTR_ERR(head);
593
594 generic_fillattr(inode, stat);
595 if (table)
596 stat->mode = (stat->mode & S_IFMT) | table->mode;
597
598 sysctl_head_finish(head);
599 return 0;
600}
601
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800602static const struct file_operations proc_sys_file_operations = {
Lucas De Marchif1ecf062011-11-02 13:39:22 -0700603 .open = proc_sys_open,
604 .poll = proc_sys_poll,
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800605 .read = proc_sys_read,
606 .write = proc_sys_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200607 .llseek = default_llseek,
Al Viro9043476f2008-07-15 08:54:06 -0400608};
609
610static const struct file_operations proc_sys_dir_file_operations = {
Pavel Emelyanov887df072011-11-02 13:38:42 -0700611 .read = generic_read_dir,
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800612 .readdir = proc_sys_readdir,
Christoph Hellwig3222a3e2008-09-03 21:53:01 +0200613 .llseek = generic_file_llseek,
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800614};
615
Jan Engelhardt03a44822008-02-08 04:21:19 -0800616static const struct inode_operations proc_sys_inode_operations = {
Al Viro9043476f2008-07-15 08:54:06 -0400617 .permission = proc_sys_permission,
618 .setattr = proc_sys_setattr,
619 .getattr = proc_sys_getattr,
620};
621
622static const struct inode_operations proc_sys_dir_operations = {
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800623 .lookup = proc_sys_lookup,
624 .permission = proc_sys_permission,
625 .setattr = proc_sys_setattr,
Al Viro9043476f2008-07-15 08:54:06 -0400626 .getattr = proc_sys_getattr,
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800627};
628
629static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd)
630{
Nick Piggin34286d62011-01-07 17:49:57 +1100631 if (nd->flags & LOOKUP_RCU)
632 return -ECHILD;
Al Viro9043476f2008-07-15 08:54:06 -0400633 return !PROC_I(dentry->d_inode)->sysctl->unregistering;
634}
635
Nick Pigginfe15ce42011-01-07 17:49:23 +1100636static int proc_sys_delete(const struct dentry *dentry)
Al Viro9043476f2008-07-15 08:54:06 -0400637{
638 return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
639}
640
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800641static int sysctl_is_seen(struct ctl_table_header *p)
642{
643 struct ctl_table_set *set = p->set;
644 int res;
645 spin_lock(&sysctl_lock);
646 if (p->unregistering)
647 res = 0;
648 else if (!set->is_seen)
649 res = 1;
650 else
651 res = set->is_seen(set);
652 spin_unlock(&sysctl_lock);
653 return res;
654}
655
Nick Piggin621e1552011-01-07 17:49:27 +1100656static int proc_sys_compare(const struct dentry *parent,
657 const struct inode *pinode,
658 const struct dentry *dentry, const struct inode *inode,
659 unsigned int len, const char *str, const struct qstr *name)
Al Viro9043476f2008-07-15 08:54:06 -0400660{
Al Virodfef6dcd32011-03-08 01:25:28 -0500661 struct ctl_table_header *head;
Nick Piggin31e6b012011-01-07 17:49:52 +1100662 /* Although proc doesn't have negative dentries, rcu-walk means
663 * that inode here can be NULL */
Al Virodfef6dcd32011-03-08 01:25:28 -0500664 /* AV: can it, indeed? */
Nick Piggin31e6b012011-01-07 17:49:52 +1100665 if (!inode)
Al Virodfef6dcd32011-03-08 01:25:28 -0500666 return 1;
Nick Piggin621e1552011-01-07 17:49:27 +1100667 if (name->len != len)
Al Viro9043476f2008-07-15 08:54:06 -0400668 return 1;
Nick Piggin621e1552011-01-07 17:49:27 +1100669 if (memcmp(name->name, str, len))
Al Viro9043476f2008-07-15 08:54:06 -0400670 return 1;
Al Virodfef6dcd32011-03-08 01:25:28 -0500671 head = rcu_dereference(PROC_I(inode)->sysctl);
672 return !head || !sysctl_is_seen(head);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800673}
674
Al Virod72f71e2009-02-20 05:58:47 +0000675static const struct dentry_operations proc_sys_dentry_operations = {
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800676 .d_revalidate = proc_sys_revalidate,
Al Viro9043476f2008-07-15 08:54:06 -0400677 .d_delete = proc_sys_delete,
678 .d_compare = proc_sys_compare,
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800679};
680
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800681static struct ctl_table *is_branch_in(struct ctl_table *branch,
682 struct ctl_table *table)
683{
684 struct ctl_table *p;
685 const char *s = branch->procname;
686
687 /* branch should have named subdirectory as its first element */
688 if (!s || !branch->child)
689 return NULL;
690
691 /* ... and nothing else */
692 if (branch[1].procname)
693 return NULL;
694
695 /* table should contain subdirectory with the same name */
696 for (p = table; p->procname; p++) {
697 if (!p->child)
698 continue;
699 if (p->procname && strcmp(p->procname, s) == 0)
700 return p;
701 }
702 return NULL;
703}
704
705/* see if attaching q to p would be an improvement */
706static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
707{
708 struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
709 struct ctl_table *next;
710 int is_better = 0;
711 int not_in_parent = !p->attached_by;
712
713 while ((next = is_branch_in(by, to)) != NULL) {
714 if (by == q->attached_by)
715 is_better = 1;
716 if (to == p->attached_by)
717 not_in_parent = 1;
718 by = by->child;
719 to = next->child;
720 }
721
722 if (is_better && not_in_parent) {
723 q->attached_by = by;
724 q->attached_to = to;
725 q->parent = p;
726 }
727}
728
729#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
730static int sysctl_depth(struct ctl_table *table)
731{
732 struct ctl_table *tmp;
733 int depth;
734
735 depth = 0;
736 for (tmp = table; tmp->parent; tmp = tmp->parent)
737 depth++;
738
739 return depth;
740}
741
742static struct ctl_table *sysctl_parent(struct ctl_table *table, int n)
743{
744 int i;
745
746 for (i = 0; table && i < n; i++)
747 table = table->parent;
748
749 return table;
750}
751
752
753static void sysctl_print_path(struct ctl_table *table)
754{
755 struct ctl_table *tmp;
756 int depth, i;
757 depth = sysctl_depth(table);
758 if (table->procname) {
759 for (i = depth; i >= 0; i--) {
760 tmp = sysctl_parent(table, i);
761 printk("/%s", tmp->procname?tmp->procname:"");
762 }
763 }
764 printk(" ");
765}
766
767static struct ctl_table *sysctl_check_lookup(struct nsproxy *namespaces,
768 struct ctl_table *table)
769{
770 struct ctl_table_header *head;
771 struct ctl_table *ref, *test;
772 int depth, cur_depth;
773
774 depth = sysctl_depth(table);
775
776 for (head = __sysctl_head_next(namespaces, NULL); head;
777 head = __sysctl_head_next(namespaces, head)) {
778 cur_depth = depth;
779 ref = head->ctl_table;
780repeat:
781 test = sysctl_parent(table, cur_depth);
782 for (; ref->procname; ref++) {
783 int match = 0;
784 if (cur_depth && !ref->child)
785 continue;
786
787 if (test->procname && ref->procname &&
788 (strcmp(test->procname, ref->procname) == 0))
789 match++;
790
791 if (match) {
792 if (cur_depth != 0) {
793 cur_depth--;
794 ref = ref->child;
795 goto repeat;
796 }
797 goto out;
798 }
799 }
800 }
801 ref = NULL;
802out:
803 sysctl_head_finish(head);
804 return ref;
805}
806
807static void set_fail(const char **fail, struct ctl_table *table, const char *str)
808{
809 if (*fail) {
810 printk(KERN_ERR "sysctl table check failed: ");
811 sysctl_print_path(table);
812 printk(" %s\n", *fail);
813 dump_stack();
814 }
815 *fail = str;
816}
817
818static void sysctl_check_leaf(struct nsproxy *namespaces,
819 struct ctl_table *table, const char **fail)
820{
821 struct ctl_table *ref;
822
823 ref = sysctl_check_lookup(namespaces, table);
824 if (ref && (ref != table))
825 set_fail(fail, table, "Sysctl already exists");
826}
827
828static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table)
829{
830 int error = 0;
831 for (; table->procname; table++) {
832 const char *fail = NULL;
833
834 if (table->parent) {
835 if (!table->parent->procname)
836 set_fail(&fail, table, "Parent without procname");
837 }
838 if (table->child) {
839 if (table->data)
840 set_fail(&fail, table, "Directory with data?");
841 if (table->maxlen)
842 set_fail(&fail, table, "Directory with maxlen?");
843 if ((table->mode & (S_IRUGO|S_IXUGO)) != table->mode)
844 set_fail(&fail, table, "Writable sysctl directory");
845 if (table->proc_handler)
846 set_fail(&fail, table, "Directory with proc_handler");
847 if (table->extra1)
848 set_fail(&fail, table, "Directory with extra1");
849 if (table->extra2)
850 set_fail(&fail, table, "Directory with extra2");
851 } else {
852 if ((table->proc_handler == proc_dostring) ||
853 (table->proc_handler == proc_dointvec) ||
854 (table->proc_handler == proc_dointvec_minmax) ||
855 (table->proc_handler == proc_dointvec_jiffies) ||
856 (table->proc_handler == proc_dointvec_userhz_jiffies) ||
857 (table->proc_handler == proc_dointvec_ms_jiffies) ||
858 (table->proc_handler == proc_doulongvec_minmax) ||
859 (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
860 if (!table->data)
861 set_fail(&fail, table, "No data");
862 if (!table->maxlen)
863 set_fail(&fail, table, "No maxlen");
864 }
865#ifdef CONFIG_PROC_SYSCTL
866 if (!table->proc_handler)
867 set_fail(&fail, table, "No proc_handler");
868#endif
869 sysctl_check_leaf(namespaces, table, &fail);
870 }
871 if (table->mode > 0777)
872 set_fail(&fail, table, "bogus .mode");
873 if (fail) {
874 set_fail(&fail, table, NULL);
875 error = -EINVAL;
876 }
877 if (table->child)
878 error |= sysctl_check_table(namespaces, table->child);
879 }
880 return error;
881}
882#endif /* CONFIG_SYSCTL_SYSCALL_CHECK */
883
884/**
Eric W. Biederman6e9d5162012-01-21 10:26:26 -0800885 * __register_sysctl_table - register a sysctl table
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800886 * @root: List of sysctl headers to register on
887 * @namespaces: Data to compute which lists of sysctl entries are visible
888 * @path: The path to the directory the sysctl table is in.
889 * @table: the top-level table structure
890 *
891 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
892 * array. A completely 0 filled entry terminates the table.
893 *
894 * The members of the &struct ctl_table structure are used as follows:
895 *
896 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
897 * enter a sysctl file
898 *
899 * data - a pointer to data for use by proc_handler
900 *
901 * maxlen - the maximum size in bytes of the data
902 *
903 * mode - the file permissions for the /proc/sys file, and for sysctl(2)
904 *
905 * child - a pointer to the child sysctl table if this entry is a directory, or
906 * %NULL.
907 *
908 * proc_handler - the text handler routine (described below)
909 *
910 * de - for internal use by the sysctl routines
911 *
912 * extra1, extra2 - extra pointers usable by the proc handler routines
913 *
914 * Leaf nodes in the sysctl tree will be represented by a single file
915 * under /proc; non-leaf nodes will be represented by directories.
916 *
917 * sysctl(2) can automatically manage read and write requests through
918 * the sysctl table. The data and maxlen fields of the ctl_table
919 * struct enable minimal validation of the values being written to be
920 * performed, and the mode field allows minimal authentication.
921 *
922 * There must be a proc_handler routine for any terminal nodes
923 * mirrored under /proc/sys (non-terminals are handled by a built-in
924 * directory handler). Several default handlers are available to
925 * cover common cases -
926 *
927 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
928 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
929 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
930 *
931 * It is the handler's job to read the input buffer from user memory
932 * and process it. The handler should return 0 on success.
933 *
934 * This routine returns %NULL on a failure to register, and a pointer
935 * to the table header on success.
936 */
Eric W. Biederman6e9d5162012-01-21 10:26:26 -0800937struct ctl_table_header *__register_sysctl_table(
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800938 struct ctl_table_root *root,
939 struct nsproxy *namespaces,
Eric W. Biederman6e9d5162012-01-21 10:26:26 -0800940 const char *path, struct ctl_table *table)
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800941{
942 struct ctl_table_header *header;
943 struct ctl_table *new, **prevp;
Eric W. Biederman6e9d5162012-01-21 10:26:26 -0800944 const char *name, *nextname;
945 unsigned int npath = 0;
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800946 struct ctl_table_set *set;
Eric W. Biedermanf05e53a2012-01-21 10:03:13 -0800947 size_t path_bytes = 0;
948 char *new_name;
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800949
950 /* Count the path components */
Eric W. Biederman6e9d5162012-01-21 10:26:26 -0800951 for (name = path; name; name = nextname) {
952 int namelen;
953 nextname = strchr(name, '/');
954 if (nextname) {
955 namelen = nextname - name;
956 nextname++;
957 } else {
958 namelen = strlen(name);
959 }
960 if (namelen == 0)
961 continue;
962 path_bytes += namelen + 1;
963 npath++;
964 }
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800965
966 /*
967 * For each path component, allocate a 2-element ctl_table array.
968 * The first array element will be filled with the sysctl entry
969 * for this, the second will be the sentinel (procname == 0).
970 *
971 * We allocate everything in one go so that we don't have to
972 * worry about freeing additional memory in unregister_sysctl_table.
973 */
Eric W. Biedermanf05e53a2012-01-21 10:03:13 -0800974 header = kzalloc(sizeof(struct ctl_table_header) + path_bytes +
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800975 (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
976 if (!header)
977 return NULL;
978
979 new = (struct ctl_table *) (header + 1);
Eric W. Biedermanf05e53a2012-01-21 10:03:13 -0800980 new_name = (char *)(new + (2 * npath));
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800981
982 /* Now connect the dots */
983 prevp = &header->ctl_table;
Eric W. Biederman6e9d5162012-01-21 10:26:26 -0800984 for (name = path; name; name = nextname) {
985 int namelen;
986 nextname = strchr(name, '/');
987 if (nextname) {
988 namelen = nextname - name;
989 nextname++;
990 } else {
991 namelen = strlen(name);
992 }
993 if (namelen == 0)
994 continue;
995 memcpy(new_name, name, namelen);
996 new_name[namelen] = '\0';
997
Eric W. Biedermanf05e53a2012-01-21 10:03:13 -0800998 new->procname = new_name;
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -0800999 new->mode = 0555;
1000
1001 *prevp = new;
1002 prevp = &new->child;
1003
1004 new += 2;
Eric W. Biederman6e9d5162012-01-21 10:26:26 -08001005 new_name += namelen + 1;
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -08001006 }
1007 *prevp = table;
1008 header->ctl_table_arg = table;
1009
1010 INIT_LIST_HEAD(&header->ctl_entry);
1011 header->used = 0;
1012 header->unregistering = NULL;
1013 header->root = root;
1014 sysctl_set_parent(NULL, header->ctl_table);
1015 header->count = 1;
1016#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1017 if (sysctl_check_table(namespaces, header->ctl_table)) {
1018 kfree(header);
1019 return NULL;
1020 }
1021#endif
1022 spin_lock(&sysctl_lock);
1023 header->set = lookup_header_set(root, namespaces);
1024 header->attached_by = header->ctl_table;
1025 header->attached_to = root_table;
1026 header->parent = &root_table_header;
Eric W. Biedermanbd295b52012-01-22 21:10:21 -08001027 set = header->set;
1028 root = header->root;
1029 for (;;) {
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -08001030 struct ctl_table_header *p;
1031 list_for_each_entry(p, &set->list, ctl_entry) {
1032 if (p->unregistering)
1033 continue;
1034 try_attach(p, header);
1035 }
Eric W. Biedermanbd295b52012-01-22 21:10:21 -08001036 if (root == &sysctl_table_root)
1037 break;
1038 root = list_entry(root->root_list.prev,
1039 struct ctl_table_root, root_list);
1040 set = lookup_header_set(root, namespaces);
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -08001041 }
1042 header->parent->count++;
1043 list_add_tail(&header->ctl_entry, &header->set->list);
1044 spin_unlock(&sysctl_lock);
1045
1046 return header;
1047}
1048
Eric W. Biederman6e9d5162012-01-21 10:26:26 -08001049static char *append_path(const char *path, char *pos, const char *name)
1050{
1051 int namelen;
1052 namelen = strlen(name);
1053 if (((pos - path) + namelen + 2) >= PATH_MAX)
1054 return NULL;
1055 memcpy(pos, name, namelen);
1056 pos[namelen] = '/';
1057 pos[namelen + 1] = '\0';
1058 pos += namelen + 1;
1059 return pos;
1060}
1061
1062/**
1063 * __register_sysctl_paths - register a sysctl table hierarchy
1064 * @root: List of sysctl headers to register on
1065 * @namespaces: Data to compute which lists of sysctl entries are visible
1066 * @path: The path to the directory the sysctl table is in.
1067 * @table: the top-level table structure
1068 *
1069 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1070 * array. A completely 0 filled entry terminates the table.
1071 *
1072 * See __register_sysctl_table for more details.
1073 */
1074struct ctl_table_header *__register_sysctl_paths(
1075 struct ctl_table_root *root,
1076 struct nsproxy *namespaces,
1077 const struct ctl_path *path, struct ctl_table *table)
1078{
Eric W. Biedermanec6a5262012-01-21 12:35:23 -08001079 struct ctl_table *ctl_table_arg = table;
Eric W. Biederman6e9d5162012-01-21 10:26:26 -08001080 struct ctl_table_header *header = NULL;
1081 const struct ctl_path *component;
1082 char *new_path, *pos;
1083
1084 pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL);
1085 if (!new_path)
1086 return NULL;
1087
1088 pos[0] = '\0';
1089 for (component = path; component->procname; component++) {
1090 pos = append_path(new_path, pos, component->procname);
1091 if (!pos)
1092 goto out;
1093 }
Eric W. Biedermanec6a5262012-01-21 12:35:23 -08001094 while (table->procname && table->child && !table[1].procname) {
1095 pos = append_path(new_path, pos, table->procname);
1096 if (!pos)
1097 goto out;
1098 table = table->child;
1099 }
Eric W. Biederman6e9d5162012-01-21 10:26:26 -08001100 header = __register_sysctl_table(root, namespaces, new_path, table);
Eric W. Biedermanec6a5262012-01-21 12:35:23 -08001101 if (header)
1102 header->ctl_table_arg = ctl_table_arg;
Eric W. Biederman6e9d5162012-01-21 10:26:26 -08001103out:
1104 kfree(new_path);
1105 return header;
1106}
1107
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -08001108/**
1109 * register_sysctl_table_path - register a sysctl table hierarchy
1110 * @path: The path to the directory the sysctl table is in.
1111 * @table: the top-level table structure
1112 *
1113 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1114 * array. A completely 0 filled entry terminates the table.
1115 *
1116 * See __register_sysctl_paths for more details.
1117 */
1118struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1119 struct ctl_table *table)
1120{
1121 return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
1122 path, table);
1123}
1124EXPORT_SYMBOL(register_sysctl_paths);
1125
1126/**
1127 * register_sysctl_table - register a sysctl table hierarchy
1128 * @table: the top-level table structure
1129 *
1130 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1131 * array. A completely 0 filled entry terminates the table.
1132 *
1133 * See register_sysctl_paths for more details.
1134 */
1135struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
1136{
1137 static const struct ctl_path null_path[] = { {} };
1138
1139 return register_sysctl_paths(null_path, table);
1140}
1141EXPORT_SYMBOL(register_sysctl_table);
1142
1143/**
1144 * unregister_sysctl_table - unregister a sysctl table hierarchy
1145 * @header: the header returned from register_sysctl_table
1146 *
1147 * Unregisters the sysctl table and all children. proc entries may not
1148 * actually be removed until they are no longer used by anyone.
1149 */
1150void unregister_sysctl_table(struct ctl_table_header * header)
1151{
1152 might_sleep();
1153
1154 if (header == NULL)
1155 return;
1156
1157 spin_lock(&sysctl_lock);
1158 start_unregistering(header);
1159 if (!--header->parent->count) {
1160 WARN_ON(1);
1161 kfree_rcu(header->parent, rcu);
1162 }
1163 if (!--header->count)
1164 kfree_rcu(header, rcu);
1165 spin_unlock(&sysctl_lock);
1166}
1167EXPORT_SYMBOL(unregister_sysctl_table);
1168
1169void setup_sysctl_set(struct ctl_table_set *p,
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -08001170 int (*is_seen)(struct ctl_table_set *))
1171{
1172 INIT_LIST_HEAD(&p->list);
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -08001173 p->is_seen = is_seen;
1174}
1175
Eric W. Biederman97324cd82012-01-09 22:19:13 -08001176void retire_sysctl_set(struct ctl_table_set *set)
1177{
1178 WARN_ON(!list_empty(&set->list));
1179}
Eric W. Biederman1f87f0b2012-01-06 04:07:15 -08001180
Alexey Dobriyan1e0edd32008-10-17 05:07:44 +04001181int __init proc_sys_init(void)
Eric W. Biederman77b14db2007-02-14 00:34:12 -08001182{
Alexey Dobriyane1675232008-10-03 00:23:32 +04001183 struct proc_dir_entry *proc_sys_root;
1184
Eric W. Biederman77b14db2007-02-14 00:34:12 -08001185 proc_sys_root = proc_mkdir("sys", NULL);
Al Viro9043476f2008-07-15 08:54:06 -04001186 proc_sys_root->proc_iops = &proc_sys_dir_operations;
1187 proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
Eric W. Biederman77b14db2007-02-14 00:34:12 -08001188 proc_sys_root->nlink = 0;
Eric W. Biedermande4e83bd2012-01-06 03:34:20 -08001189
1190 return sysctl_init();
Eric W. Biederman77b14db2007-02-14 00:34:12 -08001191}