Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
77b14db5 EB |
2 | /* |
3 | * /proc/sys support | |
4 | */ | |
1e0edd3f | 5 | #include <linux/init.h> |
77b14db5 | 6 | #include <linux/sysctl.h> |
f1ecf068 | 7 | #include <linux/poll.h> |
77b14db5 | 8 | #include <linux/proc_fs.h> |
87ebdc00 | 9 | #include <linux/printk.h> |
77b14db5 | 10 | #include <linux/security.h> |
40401530 | 11 | #include <linux/sched.h> |
5b825c3a | 12 | #include <linux/cred.h> |
34286d66 | 13 | #include <linux/namei.h> |
40401530 | 14 | #include <linux/mm.h> |
4bd6a735 | 15 | #include <linux/uio.h> |
1f87f0b5 | 16 | #include <linux/module.h> |
7b146ceb | 17 | #include <linux/bpf-cgroup.h> |
3db978d4 | 18 | #include <linux/mount.h> |
77b14db5 EB |
19 | #include "internal.h" |
20 | ||
d72f71eb | 21 | static const struct dentry_operations proc_sys_dentry_operations; |
77b14db5 | 22 | static const struct file_operations proc_sys_file_operations; |
03a44825 | 23 | static const struct inode_operations proc_sys_inode_operations; |
9043476f AV |
24 | static const struct file_operations proc_sys_dir_file_operations; |
25 | static const struct inode_operations proc_sys_dir_operations; | |
77b14db5 | 26 | |
eec4844f MC |
27 | /* shared constants to be used in various sysctls */ |
28 | const int sysctl_vals[] = { 0, 1, INT_MAX }; | |
29 | EXPORT_SYMBOL(sysctl_vals); | |
30 | ||
f9bd6733 EB |
31 | /* Support for permanently empty directories */ |
32 | ||
33 | struct ctl_table sysctl_mount_point[] = { | |
34 | { } | |
35 | }; | |
36 | ||
37 | static bool is_empty_dir(struct ctl_table_header *head) | |
38 | { | |
39 | return head->ctl_table[0].child == sysctl_mount_point; | |
40 | } | |
41 | ||
42 | static void set_empty_dir(struct ctl_dir *dir) | |
43 | { | |
44 | dir->header.ctl_table[0].child = sysctl_mount_point; | |
45 | } | |
46 | ||
47 | static void clear_empty_dir(struct ctl_dir *dir) | |
48 | ||
49 | { | |
50 | dir->header.ctl_table[0].child = NULL; | |
51 | } | |
52 | ||
f1ecf068 LDM |
53 | void proc_sys_poll_notify(struct ctl_table_poll *poll) |
54 | { | |
55 | if (!poll) | |
56 | return; | |
57 | ||
58 | atomic_inc(&poll->event); | |
59 | wake_up_interruptible(&poll->wait); | |
60 | } | |
61 | ||
a194558e EB |
62 | static struct ctl_table root_table[] = { |
63 | { | |
64 | .procname = "", | |
7ec66d06 | 65 | .mode = S_IFDIR|S_IRUGO|S_IXUGO, |
a194558e EB |
66 | }, |
67 | { } | |
68 | }; | |
0e47c99d | 69 | static struct ctl_table_root sysctl_table_root = { |
0e47c99d | 70 | .default_set.dir.header = { |
7ec66d06 EB |
71 | {{.count = 1, |
72 | .nreg = 1, | |
ac13ac6f | 73 | .ctl_table = root_table }}, |
0e47c99d | 74 | .ctl_table_arg = root_table, |
7ec66d06 EB |
75 | .root = &sysctl_table_root, |
76 | .set = &sysctl_table_root.default_set, | |
77 | }, | |
1f87f0b5 | 78 | }; |
1f87f0b5 EB |
79 | |
80 | static DEFINE_SPINLOCK(sysctl_lock); | |
81 | ||
7ec66d06 | 82 | static void drop_sysctl_table(struct ctl_table_header *header); |
0e47c99d | 83 | static int sysctl_follow_link(struct ctl_table_header **phead, |
13bcc6a2 | 84 | struct ctl_table **pentry); |
0e47c99d EB |
85 | static int insert_links(struct ctl_table_header *head); |
86 | static void put_links(struct ctl_table_header *header); | |
7ec66d06 | 87 | |
6980128f EB |
88 | static void sysctl_print_dir(struct ctl_dir *dir) |
89 | { | |
90 | if (dir->header.parent) | |
91 | sysctl_print_dir(dir->header.parent); | |
87ebdc00 | 92 | pr_cont("%s/", dir->header.ctl_table[0].procname); |
6980128f EB |
93 | } |
94 | ||
076c3eed EB |
95 | static int namecmp(const char *name1, int len1, const char *name2, int len2) |
96 | { | |
97 | int minlen; | |
98 | int cmp; | |
99 | ||
100 | minlen = len1; | |
101 | if (minlen > len2) | |
102 | minlen = len2; | |
103 | ||
104 | cmp = memcmp(name1, name2, minlen); | |
105 | if (cmp == 0) | |
106 | cmp = len1 - len2; | |
107 | return cmp; | |
108 | } | |
109 | ||
60f126d9 | 110 | /* Called under sysctl_lock */ |
076c3eed | 111 | static struct ctl_table *find_entry(struct ctl_table_header **phead, |
0e47c99d | 112 | struct ctl_dir *dir, const char *name, int namelen) |
076c3eed EB |
113 | { |
114 | struct ctl_table_header *head; | |
115 | struct ctl_table *entry; | |
ac13ac6f | 116 | struct rb_node *node = dir->root.rb_node; |
076c3eed | 117 | |
ac13ac6f EB |
118 | while (node) |
119 | { | |
120 | struct ctl_node *ctl_node; | |
121 | const char *procname; | |
122 | int cmp; | |
123 | ||
124 | ctl_node = rb_entry(node, struct ctl_node, node); | |
125 | head = ctl_node->header; | |
126 | entry = &head->ctl_table[ctl_node - head->node]; | |
127 | procname = entry->procname; | |
128 | ||
129 | cmp = namecmp(name, namelen, procname, strlen(procname)); | |
130 | if (cmp < 0) | |
131 | node = node->rb_left; | |
132 | else if (cmp > 0) | |
133 | node = node->rb_right; | |
134 | else { | |
135 | *phead = head; | |
136 | return entry; | |
076c3eed EB |
137 | } |
138 | } | |
139 | return NULL; | |
140 | } | |
141 | ||
ac13ac6f EB |
142 | static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) |
143 | { | |
144 | struct rb_node *node = &head->node[entry - head->ctl_table].node; | |
145 | struct rb_node **p = &head->parent->root.rb_node; | |
146 | struct rb_node *parent = NULL; | |
147 | const char *name = entry->procname; | |
148 | int namelen = strlen(name); | |
149 | ||
150 | while (*p) { | |
151 | struct ctl_table_header *parent_head; | |
152 | struct ctl_table *parent_entry; | |
153 | struct ctl_node *parent_node; | |
154 | const char *parent_name; | |
155 | int cmp; | |
156 | ||
157 | parent = *p; | |
158 | parent_node = rb_entry(parent, struct ctl_node, node); | |
159 | parent_head = parent_node->header; | |
160 | parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; | |
161 | parent_name = parent_entry->procname; | |
162 | ||
163 | cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); | |
164 | if (cmp < 0) | |
165 | p = &(*p)->rb_left; | |
166 | else if (cmp > 0) | |
167 | p = &(*p)->rb_right; | |
168 | else { | |
87ebdc00 | 169 | pr_err("sysctl duplicate entry: "); |
ac13ac6f | 170 | sysctl_print_dir(head->parent); |
87ebdc00 | 171 | pr_cont("/%s\n", entry->procname); |
ac13ac6f EB |
172 | return -EEXIST; |
173 | } | |
174 | } | |
175 | ||
176 | rb_link_node(node, parent, p); | |
ea5272f5 | 177 | rb_insert_color(node, &head->parent->root); |
ac13ac6f EB |
178 | return 0; |
179 | } | |
180 | ||
181 | static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) | |
182 | { | |
183 | struct rb_node *node = &head->node[entry - head->ctl_table].node; | |
184 | ||
185 | rb_erase(node, &head->parent->root); | |
186 | } | |
187 | ||
e0d04529 EB |
188 | static void init_header(struct ctl_table_header *head, |
189 | struct ctl_table_root *root, struct ctl_table_set *set, | |
ac13ac6f | 190 | struct ctl_node *node, struct ctl_table *table) |
e0d04529 | 191 | { |
7ec66d06 | 192 | head->ctl_table = table; |
e0d04529 | 193 | head->ctl_table_arg = table; |
e0d04529 EB |
194 | head->used = 0; |
195 | head->count = 1; | |
196 | head->nreg = 1; | |
197 | head->unregistering = NULL; | |
198 | head->root = root; | |
199 | head->set = set; | |
200 | head->parent = NULL; | |
ac13ac6f | 201 | head->node = node; |
2fd1d2c4 | 202 | INIT_HLIST_HEAD(&head->inodes); |
ac13ac6f EB |
203 | if (node) { |
204 | struct ctl_table *entry; | |
4c199a93 | 205 | for (entry = table; entry->procname; entry++, node++) |
ac13ac6f | 206 | node->header = head; |
ac13ac6f | 207 | } |
e0d04529 EB |
208 | } |
209 | ||
8425d6aa EB |
210 | static void erase_header(struct ctl_table_header *head) |
211 | { | |
ac13ac6f EB |
212 | struct ctl_table *entry; |
213 | for (entry = head->ctl_table; entry->procname; entry++) | |
214 | erase_entry(head, entry); | |
8425d6aa EB |
215 | } |
216 | ||
0e47c99d | 217 | static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) |
8425d6aa | 218 | { |
ac13ac6f | 219 | struct ctl_table *entry; |
0e47c99d EB |
220 | int err; |
221 | ||
f9bd6733 EB |
222 | /* Is this a permanently empty directory? */ |
223 | if (is_empty_dir(&dir->header)) | |
224 | return -EROFS; | |
225 | ||
226 | /* Am I creating a permanently empty directory? */ | |
227 | if (header->ctl_table == sysctl_mount_point) { | |
228 | if (!RB_EMPTY_ROOT(&dir->root)) | |
229 | return -EINVAL; | |
230 | set_empty_dir(dir); | |
231 | } | |
232 | ||
0e47c99d | 233 | dir->header.nreg++; |
7ec66d06 | 234 | header->parent = dir; |
0e47c99d EB |
235 | err = insert_links(header); |
236 | if (err) | |
237 | goto fail_links; | |
ac13ac6f EB |
238 | for (entry = header->ctl_table; entry->procname; entry++) { |
239 | err = insert_entry(header, entry); | |
240 | if (err) | |
241 | goto fail; | |
242 | } | |
0e47c99d | 243 | return 0; |
ac13ac6f EB |
244 | fail: |
245 | erase_header(header); | |
246 | put_links(header); | |
0e47c99d | 247 | fail_links: |
f9bd6733 EB |
248 | if (header->ctl_table == sysctl_mount_point) |
249 | clear_empty_dir(dir); | |
0e47c99d EB |
250 | header->parent = NULL; |
251 | drop_sysctl_table(&dir->header); | |
252 | return err; | |
8425d6aa EB |
253 | } |
254 | ||
1f87f0b5 EB |
255 | /* called under sysctl_lock */ |
256 | static int use_table(struct ctl_table_header *p) | |
257 | { | |
258 | if (unlikely(p->unregistering)) | |
259 | return 0; | |
260 | p->used++; | |
261 | return 1; | |
262 | } | |
263 | ||
264 | /* called under sysctl_lock */ | |
265 | static void unuse_table(struct ctl_table_header *p) | |
266 | { | |
267 | if (!--p->used) | |
268 | if (unlikely(p->unregistering)) | |
269 | complete(p->unregistering); | |
270 | } | |
271 | ||
f90f3caf | 272 | static void proc_sys_invalidate_dcache(struct ctl_table_header *head) |
d6cffbbe | 273 | { |
f90f3caf | 274 | proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); |
d6cffbbe KK |
275 | } |
276 | ||
1f87f0b5 EB |
277 | /* called under sysctl_lock, will reacquire if has to wait */ |
278 | static void start_unregistering(struct ctl_table_header *p) | |
279 | { | |
280 | /* | |
281 | * if p->used is 0, nobody will ever touch that entry again; | |
282 | * we'll eliminate all paths to it before dropping sysctl_lock | |
283 | */ | |
284 | if (unlikely(p->used)) { | |
285 | struct completion wait; | |
286 | init_completion(&wait); | |
287 | p->unregistering = &wait; | |
288 | spin_unlock(&sysctl_lock); | |
289 | wait_for_completion(&wait); | |
1f87f0b5 EB |
290 | } else { |
291 | /* anything non-NULL; we'll never dereference it */ | |
292 | p->unregistering = ERR_PTR(-EINVAL); | |
ace0c791 | 293 | spin_unlock(&sysctl_lock); |
1f87f0b5 | 294 | } |
d6cffbbe | 295 | /* |
f90f3caf | 296 | * Invalidate dentries for unregistered sysctls: namespaced sysctls |
d6cffbbe KK |
297 | * can have duplicate names and contaminate dcache very badly. |
298 | */ | |
f90f3caf | 299 | proc_sys_invalidate_dcache(p); |
1f87f0b5 EB |
300 | /* |
301 | * do not remove from the list until nobody holds it; walking the | |
302 | * list in do_sysctl() relies on that. | |
303 | */ | |
ace0c791 | 304 | spin_lock(&sysctl_lock); |
8425d6aa | 305 | erase_header(p); |
1f87f0b5 EB |
306 | } |
307 | ||
1f87f0b5 EB |
308 | static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) |
309 | { | |
ab4a1f24 | 310 | BUG_ON(!head); |
1f87f0b5 EB |
311 | spin_lock(&sysctl_lock); |
312 | if (!use_table(head)) | |
313 | head = ERR_PTR(-ENOENT); | |
314 | spin_unlock(&sysctl_lock); | |
315 | return head; | |
316 | } | |
317 | ||
318 | static void sysctl_head_finish(struct ctl_table_header *head) | |
319 | { | |
320 | if (!head) | |
321 | return; | |
322 | spin_lock(&sysctl_lock); | |
323 | unuse_table(head); | |
324 | spin_unlock(&sysctl_lock); | |
325 | } | |
326 | ||
327 | static struct ctl_table_set * | |
13bcc6a2 | 328 | lookup_header_set(struct ctl_table_root *root) |
1f87f0b5 EB |
329 | { |
330 | struct ctl_table_set *set = &root->default_set; | |
331 | if (root->lookup) | |
13bcc6a2 | 332 | set = root->lookup(root); |
1f87f0b5 EB |
333 | return set; |
334 | } | |
335 | ||
076c3eed | 336 | static struct ctl_table *lookup_entry(struct ctl_table_header **phead, |
7ec66d06 | 337 | struct ctl_dir *dir, |
076c3eed EB |
338 | const char *name, int namelen) |
339 | { | |
340 | struct ctl_table_header *head; | |
341 | struct ctl_table *entry; | |
076c3eed EB |
342 | |
343 | spin_lock(&sysctl_lock); | |
0e47c99d EB |
344 | entry = find_entry(&head, dir, name, namelen); |
345 | if (entry && use_table(head)) | |
346 | *phead = head; | |
347 | else | |
348 | entry = NULL; | |
076c3eed EB |
349 | spin_unlock(&sysctl_lock); |
350 | return entry; | |
351 | } | |
352 | ||
ac13ac6f | 353 | static struct ctl_node *first_usable_entry(struct rb_node *node) |
1f87f0b5 | 354 | { |
ac13ac6f | 355 | struct ctl_node *ctl_node; |
1f87f0b5 | 356 | |
ac13ac6f EB |
357 | for (;node; node = rb_next(node)) { |
358 | ctl_node = rb_entry(node, struct ctl_node, node); | |
359 | if (use_table(ctl_node->header)) | |
360 | return ctl_node; | |
1f87f0b5 | 361 | } |
1f87f0b5 EB |
362 | return NULL; |
363 | } | |
364 | ||
7ec66d06 | 365 | static void first_entry(struct ctl_dir *dir, |
6a75ce16 EB |
366 | struct ctl_table_header **phead, struct ctl_table **pentry) |
367 | { | |
ac13ac6f | 368 | struct ctl_table_header *head = NULL; |
7ec66d06 | 369 | struct ctl_table *entry = NULL; |
ac13ac6f | 370 | struct ctl_node *ctl_node; |
6a75ce16 EB |
371 | |
372 | spin_lock(&sysctl_lock); | |
ac13ac6f | 373 | ctl_node = first_usable_entry(rb_first(&dir->root)); |
6a75ce16 | 374 | spin_unlock(&sysctl_lock); |
ac13ac6f EB |
375 | if (ctl_node) { |
376 | head = ctl_node->header; | |
377 | entry = &head->ctl_table[ctl_node - head->node]; | |
378 | } | |
6a75ce16 EB |
379 | *phead = head; |
380 | *pentry = entry; | |
381 | } | |
382 | ||
7ec66d06 | 383 | static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) |
1f87f0b5 | 384 | { |
6a75ce16 EB |
385 | struct ctl_table_header *head = *phead; |
386 | struct ctl_table *entry = *pentry; | |
ac13ac6f | 387 | struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; |
6a75ce16 | 388 | |
ac13ac6f EB |
389 | spin_lock(&sysctl_lock); |
390 | unuse_table(head); | |
391 | ||
392 | ctl_node = first_usable_entry(rb_next(&ctl_node->node)); | |
393 | spin_unlock(&sysctl_lock); | |
394 | head = NULL; | |
395 | if (ctl_node) { | |
396 | head = ctl_node->header; | |
397 | entry = &head->ctl_table[ctl_node - head->node]; | |
6a75ce16 EB |
398 | } |
399 | *phead = head; | |
400 | *pentry = entry; | |
1f87f0b5 EB |
401 | } |
402 | ||
1f87f0b5 EB |
403 | /* |
404 | * sysctl_perm does NOT grant the superuser all rights automatically, because | |
405 | * some sysctl variables are readonly even to root. | |
406 | */ | |
407 | ||
408 | static int test_perm(int mode, int op) | |
409 | { | |
091bd3ea | 410 | if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) |
1f87f0b5 | 411 | mode >>= 6; |
091bd3ea | 412 | else if (in_egroup_p(GLOBAL_ROOT_GID)) |
1f87f0b5 EB |
413 | mode >>= 3; |
414 | if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) | |
415 | return 0; | |
416 | return -EACCES; | |
417 | } | |
418 | ||
73f7ef43 | 419 | static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) |
1f87f0b5 | 420 | { |
73f7ef43 | 421 | struct ctl_table_root *root = head->root; |
1f87f0b5 EB |
422 | int mode; |
423 | ||
424 | if (root->permissions) | |
73f7ef43 | 425 | mode = root->permissions(head, table); |
1f87f0b5 EB |
426 | else |
427 | mode = table->mode; | |
428 | ||
429 | return test_perm(mode, op); | |
430 | } | |
431 | ||
9043476f AV |
432 | static struct inode *proc_sys_make_inode(struct super_block *sb, |
433 | struct ctl_table_header *head, struct ctl_table *table) | |
77b14db5 | 434 | { |
e79c6a4f | 435 | struct ctl_table_root *root = head->root; |
77b14db5 | 436 | struct inode *inode; |
9043476f | 437 | struct proc_inode *ei; |
77b14db5 | 438 | |
9043476f | 439 | inode = new_inode(sb); |
77b14db5 | 440 | if (!inode) |
ea5751cc | 441 | return ERR_PTR(-ENOMEM); |
77b14db5 | 442 | |
85fe4025 CH |
443 | inode->i_ino = get_next_ino(); |
444 | ||
77b14db5 | 445 | ei = PROC_I(inode); |
9043476f | 446 | |
d6cffbbe | 447 | spin_lock(&sysctl_lock); |
ace0c791 EB |
448 | if (unlikely(head->unregistering)) { |
449 | spin_unlock(&sysctl_lock); | |
450 | iput(inode); | |
ea5751cc | 451 | return ERR_PTR(-ENOENT); |
ace0c791 EB |
452 | } |
453 | ei->sysctl = head; | |
454 | ei->sysctl_entry = table; | |
0afa5ca8 | 455 | hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes); |
d6cffbbe KK |
456 | head->count++; |
457 | spin_unlock(&sysctl_lock); | |
458 | ||
078cd827 | 459 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); |
9043476f | 460 | inode->i_mode = table->mode; |
7ec66d06 | 461 | if (!S_ISDIR(table->mode)) { |
9043476f AV |
462 | inode->i_mode |= S_IFREG; |
463 | inode->i_op = &proc_sys_inode_operations; | |
464 | inode->i_fop = &proc_sys_file_operations; | |
465 | } else { | |
466 | inode->i_mode |= S_IFDIR; | |
9043476f AV |
467 | inode->i_op = &proc_sys_dir_operations; |
468 | inode->i_fop = &proc_sys_dir_file_operations; | |
f9bd6733 EB |
469 | if (is_empty_dir(head)) |
470 | make_empty_dir_inode(inode); | |
9043476f | 471 | } |
e79c6a4f DT |
472 | |
473 | if (root->set_ownership) | |
474 | root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); | |
5ec27ec7 RB |
475 | else { |
476 | inode->i_uid = GLOBAL_ROOT_UID; | |
477 | inode->i_gid = GLOBAL_ROOT_GID; | |
478 | } | |
e79c6a4f | 479 | |
77b14db5 EB |
480 | return inode; |
481 | } | |
482 | ||
d6cffbbe KK |
483 | void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) |
484 | { | |
485 | spin_lock(&sysctl_lock); | |
0afa5ca8 | 486 | hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes); |
d6cffbbe KK |
487 | if (!--head->count) |
488 | kfree_rcu(head, rcu); | |
489 | spin_unlock(&sysctl_lock); | |
490 | } | |
491 | ||
81324364 | 492 | static struct ctl_table_header *grab_header(struct inode *inode) |
77b14db5 | 493 | { |
3cc3e046 EB |
494 | struct ctl_table_header *head = PROC_I(inode)->sysctl; |
495 | if (!head) | |
0e47c99d | 496 | head = &sysctl_table_root.default_set.dir.header; |
3cc3e046 | 497 | return sysctl_head_grab(head); |
9043476f | 498 | } |
77b14db5 | 499 | |
9043476f | 500 | static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, |
00cd8dd3 | 501 | unsigned int flags) |
9043476f AV |
502 | { |
503 | struct ctl_table_header *head = grab_header(dir); | |
9043476f | 504 | struct ctl_table_header *h = NULL; |
dc12e909 | 505 | const struct qstr *name = &dentry->d_name; |
9043476f AV |
506 | struct ctl_table *p; |
507 | struct inode *inode; | |
508 | struct dentry *err = ERR_PTR(-ENOENT); | |
7ec66d06 | 509 | struct ctl_dir *ctl_dir; |
0e47c99d | 510 | int ret; |
77b14db5 | 511 | |
9043476f AV |
512 | if (IS_ERR(head)) |
513 | return ERR_CAST(head); | |
77b14db5 | 514 | |
7ec66d06 | 515 | ctl_dir = container_of(head, struct ctl_dir, header); |
77b14db5 | 516 | |
7ec66d06 | 517 | p = lookup_entry(&h, ctl_dir, name->name, name->len); |
9043476f | 518 | if (!p) |
77b14db5 EB |
519 | goto out; |
520 | ||
4e757320 | 521 | if (S_ISLNK(p->mode)) { |
13bcc6a2 | 522 | ret = sysctl_follow_link(&h, &p); |
4e757320 EB |
523 | err = ERR_PTR(ret); |
524 | if (ret) | |
525 | goto out; | |
526 | } | |
0e47c99d | 527 | |
9043476f | 528 | inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); |
ea5751cc ID |
529 | if (IS_ERR(inode)) { |
530 | err = ERR_CAST(inode); | |
77b14db5 | 531 | goto out; |
ea5751cc | 532 | } |
77b14db5 | 533 | |
fb045adb | 534 | d_set_d_op(dentry, &proc_sys_dentry_operations); |
888e2b03 | 535 | err = d_splice_alias(inode, dentry); |
77b14db5 EB |
536 | |
537 | out: | |
6bf61045 FR |
538 | if (h) |
539 | sysctl_head_finish(h); | |
77b14db5 EB |
540 | sysctl_head_finish(head); |
541 | return err; | |
542 | } | |
543 | ||
4bd6a735 MWO |
544 | static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, |
545 | int write) | |
77b14db5 | 546 | { |
4bd6a735 | 547 | struct inode *inode = file_inode(iocb->ki_filp); |
9043476f AV |
548 | struct ctl_table_header *head = grab_header(inode); |
549 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
4bd6a735 MWO |
550 | size_t count = iov_iter_count(iter); |
551 | char *kbuf; | |
2a2da53b | 552 | ssize_t error; |
77b14db5 | 553 | |
9043476f AV |
554 | if (IS_ERR(head)) |
555 | return PTR_ERR(head); | |
77b14db5 EB |
556 | |
557 | /* | |
558 | * At this point we know that the sysctl was not unregistered | |
559 | * and won't be until we finish. | |
560 | */ | |
561 | error = -EPERM; | |
73f7ef43 | 562 | if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) |
77b14db5 EB |
563 | goto out; |
564 | ||
9043476f AV |
565 | /* if that can happen at all, it should be -EINVAL, not -EISDIR */ |
566 | error = -EINVAL; | |
567 | if (!table->proc_handler) | |
568 | goto out; | |
569 | ||
ef9d965b | 570 | /* don't even try if the size is too large */ |
d4d80e69 MWO |
571 | error = -ENOMEM; |
572 | if (count >= KMALLOC_MAX_SIZE) | |
573 | goto out; | |
4bd6a735 MWO |
574 | kbuf = kzalloc(count + 1, GFP_KERNEL); |
575 | if (!kbuf) | |
576 | goto out; | |
ef9d965b | 577 | |
32927393 | 578 | if (write) { |
4bd6a735 MWO |
579 | error = -EFAULT; |
580 | if (!copy_from_iter_full(kbuf, count, iter)) | |
581 | goto out_free_buf; | |
582 | kbuf[count] = '\0'; | |
32927393 CH |
583 | } |
584 | ||
585 | error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count, | |
4bd6a735 | 586 | &iocb->ki_pos); |
7b146ceb | 587 | if (error) |
32927393 | 588 | goto out_free_buf; |
7b146ceb | 589 | |
77b14db5 | 590 | /* careful: calling conventions are nasty here */ |
4bd6a735 | 591 | error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos); |
32927393 CH |
592 | if (error) |
593 | goto out_free_buf; | |
594 | ||
595 | if (!write) { | |
596 | error = -EFAULT; | |
4bd6a735 | 597 | if (copy_to_iter(kbuf, count, iter) < count) |
32927393 | 598 | goto out_free_buf; |
4e63acdf AI |
599 | } |
600 | ||
32927393 CH |
601 | error = count; |
602 | out_free_buf: | |
603 | kfree(kbuf); | |
77b14db5 EB |
604 | out: |
605 | sysctl_head_finish(head); | |
606 | ||
607 | return error; | |
608 | } | |
609 | ||
4bd6a735 | 610 | static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter) |
77b14db5 | 611 | { |
4bd6a735 | 612 | return proc_sys_call_handler(iocb, iter, 0); |
7708bfb1 | 613 | } |
77b14db5 | 614 | |
4bd6a735 | 615 | static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter) |
7708bfb1 | 616 | { |
4bd6a735 | 617 | return proc_sys_call_handler(iocb, iter, 1); |
77b14db5 EB |
618 | } |
619 | ||
f1ecf068 LDM |
620 | static int proc_sys_open(struct inode *inode, struct file *filp) |
621 | { | |
4e474a00 | 622 | struct ctl_table_header *head = grab_header(inode); |
f1ecf068 LDM |
623 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
624 | ||
4e474a00 LDM |
625 | /* sysctl was unregistered */ |
626 | if (IS_ERR(head)) | |
627 | return PTR_ERR(head); | |
628 | ||
f1ecf068 LDM |
629 | if (table->poll) |
630 | filp->private_data = proc_sys_poll_event(table->poll); | |
631 | ||
4e474a00 LDM |
632 | sysctl_head_finish(head); |
633 | ||
f1ecf068 LDM |
634 | return 0; |
635 | } | |
636 | ||
076ccb76 | 637 | static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) |
f1ecf068 | 638 | { |
496ad9aa | 639 | struct inode *inode = file_inode(filp); |
4e474a00 | 640 | struct ctl_table_header *head = grab_header(inode); |
f1ecf068 | 641 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
076ccb76 | 642 | __poll_t ret = DEFAULT_POLLMASK; |
4e474a00 LDM |
643 | unsigned long event; |
644 | ||
645 | /* sysctl was unregistered */ | |
646 | if (IS_ERR(head)) | |
a9a08845 | 647 | return EPOLLERR | EPOLLHUP; |
f1ecf068 LDM |
648 | |
649 | if (!table->proc_handler) | |
650 | goto out; | |
651 | ||
652 | if (!table->poll) | |
653 | goto out; | |
654 | ||
4e474a00 | 655 | event = (unsigned long)filp->private_data; |
f1ecf068 LDM |
656 | poll_wait(filp, &table->poll->wait, wait); |
657 | ||
658 | if (event != atomic_read(&table->poll->event)) { | |
659 | filp->private_data = proc_sys_poll_event(table->poll); | |
a9a08845 | 660 | ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; |
f1ecf068 LDM |
661 | } |
662 | ||
663 | out: | |
4e474a00 LDM |
664 | sysctl_head_finish(head); |
665 | ||
f1ecf068 LDM |
666 | return ret; |
667 | } | |
77b14db5 | 668 | |
f0c3b509 AV |
669 | static bool proc_sys_fill_cache(struct file *file, |
670 | struct dir_context *ctx, | |
9043476f AV |
671 | struct ctl_table_header *head, |
672 | struct ctl_table *table) | |
77b14db5 | 673 | { |
f0c3b509 | 674 | struct dentry *child, *dir = file->f_path.dentry; |
77b14db5 EB |
675 | struct inode *inode; |
676 | struct qstr qname; | |
677 | ino_t ino = 0; | |
678 | unsigned type = DT_UNKNOWN; | |
77b14db5 EB |
679 | |
680 | qname.name = table->procname; | |
681 | qname.len = strlen(table->procname); | |
8387ff25 | 682 | qname.hash = full_name_hash(dir, qname.name, qname.len); |
77b14db5 | 683 | |
77b14db5 EB |
684 | child = d_lookup(dir, &qname); |
685 | if (!child) { | |
76aab3ab AV |
686 | DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); |
687 | child = d_alloc_parallel(dir, &qname, &wq); | |
688 | if (IS_ERR(child)) | |
689 | return false; | |
690 | if (d_in_lookup(child)) { | |
888e2b03 | 691 | struct dentry *res; |
9043476f | 692 | inode = proc_sys_make_inode(dir->d_sb, head, table); |
ea5751cc | 693 | if (IS_ERR(inode)) { |
76aab3ab | 694 | d_lookup_done(child); |
9043476f | 695 | dput(child); |
f0c3b509 | 696 | return false; |
77b14db5 | 697 | } |
76aab3ab | 698 | d_set_d_op(child, &proc_sys_dentry_operations); |
888e2b03 AV |
699 | res = d_splice_alias(inode, child); |
700 | d_lookup_done(child); | |
701 | if (unlikely(res)) { | |
702 | if (IS_ERR(res)) { | |
703 | dput(child); | |
704 | return false; | |
705 | } | |
706 | dput(child); | |
707 | child = res; | |
708 | } | |
77b14db5 EB |
709 | } |
710 | } | |
2b0143b5 | 711 | inode = d_inode(child); |
9043476f AV |
712 | ino = inode->i_ino; |
713 | type = inode->i_mode >> 12; | |
77b14db5 | 714 | dput(child); |
f0c3b509 | 715 | return dir_emit(ctx, qname.name, qname.len, ino, type); |
9043476f AV |
716 | } |
717 | ||
f0c3b509 AV |
718 | static bool proc_sys_link_fill_cache(struct file *file, |
719 | struct dir_context *ctx, | |
0e47c99d EB |
720 | struct ctl_table_header *head, |
721 | struct ctl_table *table) | |
722 | { | |
f0c3b509 | 723 | bool ret = true; |
a0b0d1c3 | 724 | |
0e47c99d | 725 | head = sysctl_head_grab(head); |
a0b0d1c3 DK |
726 | if (IS_ERR(head)) |
727 | return false; | |
0e47c99d | 728 | |
835b94e0 DK |
729 | /* It is not an error if we can not follow the link ignore it */ |
730 | if (sysctl_follow_link(&head, &table)) | |
731 | goto out; | |
0e47c99d | 732 | |
f0c3b509 | 733 | ret = proc_sys_fill_cache(file, ctx, head, table); |
0e47c99d EB |
734 | out: |
735 | sysctl_head_finish(head); | |
736 | return ret; | |
737 | } | |
738 | ||
e5eea098 | 739 | static int scan(struct ctl_table_header *head, struct ctl_table *table, |
9043476f | 740 | unsigned long *pos, struct file *file, |
f0c3b509 | 741 | struct dir_context *ctx) |
9043476f | 742 | { |
f0c3b509 | 743 | bool res; |
9043476f | 744 | |
f0c3b509 AV |
745 | if ((*pos)++ < ctx->pos) |
746 | return true; | |
9043476f | 747 | |
0e47c99d | 748 | if (unlikely(S_ISLNK(table->mode))) |
f0c3b509 | 749 | res = proc_sys_link_fill_cache(file, ctx, head, table); |
0e47c99d | 750 | else |
f0c3b509 | 751 | res = proc_sys_fill_cache(file, ctx, head, table); |
9043476f | 752 | |
f0c3b509 AV |
753 | if (res) |
754 | ctx->pos = *pos; | |
9043476f | 755 | |
6a75ce16 | 756 | return res; |
77b14db5 EB |
757 | } |
758 | ||
f0c3b509 | 759 | static int proc_sys_readdir(struct file *file, struct dir_context *ctx) |
77b14db5 | 760 | { |
f0c3b509 | 761 | struct ctl_table_header *head = grab_header(file_inode(file)); |
9043476f | 762 | struct ctl_table_header *h = NULL; |
6a75ce16 | 763 | struct ctl_table *entry; |
7ec66d06 | 764 | struct ctl_dir *ctl_dir; |
77b14db5 | 765 | unsigned long pos; |
9043476f AV |
766 | |
767 | if (IS_ERR(head)) | |
768 | return PTR_ERR(head); | |
77b14db5 | 769 | |
7ec66d06 | 770 | ctl_dir = container_of(head, struct ctl_dir, header); |
77b14db5 | 771 | |
f0c3b509 | 772 | if (!dir_emit_dots(file, ctx)) |
93362fa4 | 773 | goto out; |
f0c3b509 | 774 | |
77b14db5 EB |
775 | pos = 2; |
776 | ||
7ec66d06 | 777 | for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { |
f0c3b509 | 778 | if (!scan(h, entry, &pos, file, ctx)) { |
9043476f AV |
779 | sysctl_head_finish(h); |
780 | break; | |
77b14db5 EB |
781 | } |
782 | } | |
93362fa4 | 783 | out: |
77b14db5 | 784 | sysctl_head_finish(head); |
f0c3b509 | 785 | return 0; |
77b14db5 EB |
786 | } |
787 | ||
10556cb2 | 788 | static int proc_sys_permission(struct inode *inode, int mask) |
77b14db5 EB |
789 | { |
790 | /* | |
791 | * sysctl entries that are not writeable, | |
792 | * are _NOT_ writeable, capabilities or not. | |
793 | */ | |
f696a365 MS |
794 | struct ctl_table_header *head; |
795 | struct ctl_table *table; | |
77b14db5 EB |
796 | int error; |
797 | ||
f696a365 MS |
798 | /* Executable files are not allowed under /proc/sys/ */ |
799 | if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) | |
800 | return -EACCES; | |
801 | ||
802 | head = grab_header(inode); | |
9043476f AV |
803 | if (IS_ERR(head)) |
804 | return PTR_ERR(head); | |
77b14db5 | 805 | |
f696a365 | 806 | table = PROC_I(inode)->sysctl_entry; |
9043476f AV |
807 | if (!table) /* global root - r-xr-xr-x */ |
808 | error = mask & MAY_WRITE ? -EACCES : 0; | |
809 | else /* Use the permissions on the sysctl table entry */ | |
73f7ef43 | 810 | error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); |
77b14db5 | 811 | |
77b14db5 EB |
812 | sysctl_head_finish(head); |
813 | return error; | |
814 | } | |
815 | ||
816 | static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) | |
817 | { | |
2b0143b5 | 818 | struct inode *inode = d_inode(dentry); |
77b14db5 EB |
819 | int error; |
820 | ||
821 | if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) | |
822 | return -EPERM; | |
823 | ||
2f221d6f | 824 | error = setattr_prepare(&init_user_ns, dentry, attr); |
1025774c CH |
825 | if (error) |
826 | return error; | |
827 | ||
2f221d6f | 828 | setattr_copy(&init_user_ns, inode, attr); |
1025774c CH |
829 | mark_inode_dirty(inode); |
830 | return 0; | |
77b14db5 EB |
831 | } |
832 | ||
a528d35e DH |
833 | static int proc_sys_getattr(const struct path *path, struct kstat *stat, |
834 | u32 request_mask, unsigned int query_flags) | |
9043476f | 835 | { |
a528d35e | 836 | struct inode *inode = d_inode(path->dentry); |
9043476f AV |
837 | struct ctl_table_header *head = grab_header(inode); |
838 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
839 | ||
840 | if (IS_ERR(head)) | |
841 | return PTR_ERR(head); | |
842 | ||
843 | generic_fillattr(inode, stat); | |
844 | if (table) | |
845 | stat->mode = (stat->mode & S_IFMT) | table->mode; | |
846 | ||
847 | sysctl_head_finish(head); | |
848 | return 0; | |
849 | } | |
850 | ||
77b14db5 | 851 | static const struct file_operations proc_sys_file_operations = { |
f1ecf068 LDM |
852 | .open = proc_sys_open, |
853 | .poll = proc_sys_poll, | |
4bd6a735 MWO |
854 | .read_iter = proc_sys_read, |
855 | .write_iter = proc_sys_write, | |
856 | .splice_read = generic_file_splice_read, | |
857 | .splice_write = iter_file_splice_write, | |
6038f373 | 858 | .llseek = default_llseek, |
9043476f AV |
859 | }; |
860 | ||
861 | static const struct file_operations proc_sys_dir_file_operations = { | |
887df078 | 862 | .read = generic_read_dir, |
f50752ea | 863 | .iterate_shared = proc_sys_readdir, |
3222a3e5 | 864 | .llseek = generic_file_llseek, |
77b14db5 EB |
865 | }; |
866 | ||
03a44825 | 867 | static const struct inode_operations proc_sys_inode_operations = { |
9043476f AV |
868 | .permission = proc_sys_permission, |
869 | .setattr = proc_sys_setattr, | |
870 | .getattr = proc_sys_getattr, | |
871 | }; | |
872 | ||
873 | static const struct inode_operations proc_sys_dir_operations = { | |
77b14db5 EB |
874 | .lookup = proc_sys_lookup, |
875 | .permission = proc_sys_permission, | |
876 | .setattr = proc_sys_setattr, | |
9043476f | 877 | .getattr = proc_sys_getattr, |
77b14db5 EB |
878 | }; |
879 | ||
0b728e19 | 880 | static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) |
77b14db5 | 881 | { |
0b728e19 | 882 | if (flags & LOOKUP_RCU) |
34286d66 | 883 | return -ECHILD; |
2b0143b5 | 884 | return !PROC_I(d_inode(dentry))->sysctl->unregistering; |
9043476f AV |
885 | } |
886 | ||
fe15ce44 | 887 | static int proc_sys_delete(const struct dentry *dentry) |
9043476f | 888 | { |
2b0143b5 | 889 | return !!PROC_I(d_inode(dentry))->sysctl->unregistering; |
9043476f AV |
890 | } |
891 | ||
1f87f0b5 EB |
892 | static int sysctl_is_seen(struct ctl_table_header *p) |
893 | { | |
894 | struct ctl_table_set *set = p->set; | |
895 | int res; | |
896 | spin_lock(&sysctl_lock); | |
897 | if (p->unregistering) | |
898 | res = 0; | |
899 | else if (!set->is_seen) | |
900 | res = 1; | |
901 | else | |
902 | res = set->is_seen(set); | |
903 | spin_unlock(&sysctl_lock); | |
904 | return res; | |
905 | } | |
906 | ||
6fa67e70 | 907 | static int proc_sys_compare(const struct dentry *dentry, |
621e155a | 908 | unsigned int len, const char *str, const struct qstr *name) |
9043476f | 909 | { |
dfef6dcd | 910 | struct ctl_table_header *head; |
da53be12 LT |
911 | struct inode *inode; |
912 | ||
31e6b01f NP |
913 | /* Although proc doesn't have negative dentries, rcu-walk means |
914 | * that inode here can be NULL */ | |
dfef6dcd | 915 | /* AV: can it, indeed? */ |
2b0143b5 | 916 | inode = d_inode_rcu(dentry); |
31e6b01f | 917 | if (!inode) |
dfef6dcd | 918 | return 1; |
621e155a | 919 | if (name->len != len) |
9043476f | 920 | return 1; |
621e155a | 921 | if (memcmp(name->name, str, len)) |
9043476f | 922 | return 1; |
dfef6dcd AV |
923 | head = rcu_dereference(PROC_I(inode)->sysctl); |
924 | return !head || !sysctl_is_seen(head); | |
77b14db5 EB |
925 | } |
926 | ||
d72f71eb | 927 | static const struct dentry_operations proc_sys_dentry_operations = { |
77b14db5 | 928 | .d_revalidate = proc_sys_revalidate, |
9043476f AV |
929 | .d_delete = proc_sys_delete, |
930 | .d_compare = proc_sys_compare, | |
77b14db5 EB |
931 | }; |
932 | ||
0e47c99d EB |
933 | static struct ctl_dir *find_subdir(struct ctl_dir *dir, |
934 | const char *name, int namelen) | |
1f87f0b5 | 935 | { |
7ec66d06 EB |
936 | struct ctl_table_header *head; |
937 | struct ctl_table *entry; | |
1f87f0b5 | 938 | |
0e47c99d | 939 | entry = find_entry(&head, dir, name, namelen); |
7ec66d06 EB |
940 | if (!entry) |
941 | return ERR_PTR(-ENOENT); | |
51f72f4a EB |
942 | if (!S_ISDIR(entry->mode)) |
943 | return ERR_PTR(-ENOTDIR); | |
944 | return container_of(head, struct ctl_dir, header); | |
7ec66d06 EB |
945 | } |
946 | ||
947 | static struct ctl_dir *new_dir(struct ctl_table_set *set, | |
0e47c99d | 948 | const char *name, int namelen) |
7ec66d06 EB |
949 | { |
950 | struct ctl_table *table; | |
951 | struct ctl_dir *new; | |
ac13ac6f | 952 | struct ctl_node *node; |
7ec66d06 | 953 | char *new_name; |
1f87f0b5 | 954 | |
ac13ac6f EB |
955 | new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + |
956 | sizeof(struct ctl_table)*2 + namelen + 1, | |
957 | GFP_KERNEL); | |
7ec66d06 | 958 | if (!new) |
1f87f0b5 EB |
959 | return NULL; |
960 | ||
ac13ac6f EB |
961 | node = (struct ctl_node *)(new + 1); |
962 | table = (struct ctl_table *)(node + 1); | |
7ec66d06 EB |
963 | new_name = (char *)(table + 2); |
964 | memcpy(new_name, name, namelen); | |
965 | new_name[namelen] = '\0'; | |
966 | table[0].procname = new_name; | |
967 | table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; | |
ac13ac6f | 968 | init_header(&new->header, set->dir.header.root, set, node, table); |
7ec66d06 EB |
969 | |
970 | return new; | |
1f87f0b5 EB |
971 | } |
972 | ||
60f126d9 EB |
973 | /** |
974 | * get_subdir - find or create a subdir with the specified name. | |
975 | * @dir: Directory to create the subdirectory in | |
976 | * @name: The name of the subdirectory to find or create | |
977 | * @namelen: The length of name | |
978 | * | |
979 | * Takes a directory with an elevated reference count so we know that | |
980 | * if we drop the lock the directory will not go away. Upon success | |
981 | * the reference is moved from @dir to the returned subdirectory. | |
982 | * Upon error an error code is returned and the reference on @dir is | |
983 | * simply dropped. | |
984 | */ | |
0e47c99d EB |
985 | static struct ctl_dir *get_subdir(struct ctl_dir *dir, |
986 | const char *name, int namelen) | |
1f87f0b5 | 987 | { |
0e47c99d | 988 | struct ctl_table_set *set = dir->header.set; |
7ec66d06 | 989 | struct ctl_dir *subdir, *new = NULL; |
0eb97f38 | 990 | int err; |
1f87f0b5 | 991 | |
7ec66d06 | 992 | spin_lock(&sysctl_lock); |
0e47c99d | 993 | subdir = find_subdir(dir, name, namelen); |
7ec66d06 EB |
994 | if (!IS_ERR(subdir)) |
995 | goto found; | |
996 | if (PTR_ERR(subdir) != -ENOENT) | |
997 | goto failed; | |
998 | ||
999 | spin_unlock(&sysctl_lock); | |
1000 | new = new_dir(set, name, namelen); | |
1001 | spin_lock(&sysctl_lock); | |
1002 | subdir = ERR_PTR(-ENOMEM); | |
1003 | if (!new) | |
1004 | goto failed; | |
1005 | ||
60f126d9 | 1006 | /* Was the subdir added while we dropped the lock? */ |
0e47c99d | 1007 | subdir = find_subdir(dir, name, namelen); |
7ec66d06 EB |
1008 | if (!IS_ERR(subdir)) |
1009 | goto found; | |
1010 | if (PTR_ERR(subdir) != -ENOENT) | |
1011 | goto failed; | |
1012 | ||
60f126d9 | 1013 | /* Nope. Use the our freshly made directory entry. */ |
0eb97f38 EB |
1014 | err = insert_header(dir, &new->header); |
1015 | subdir = ERR_PTR(err); | |
1016 | if (err) | |
0e47c99d | 1017 | goto failed; |
7ec66d06 EB |
1018 | subdir = new; |
1019 | found: | |
1020 | subdir->header.nreg++; | |
1021 | failed: | |
a1c83681 | 1022 | if (IS_ERR(subdir)) { |
87ebdc00 | 1023 | pr_err("sysctl could not get directory: "); |
6980128f | 1024 | sysctl_print_dir(dir); |
87ebdc00 | 1025 | pr_cont("/%*.*s %ld\n", |
7ec66d06 | 1026 | namelen, namelen, name, PTR_ERR(subdir)); |
1f87f0b5 | 1027 | } |
7ec66d06 EB |
1028 | drop_sysctl_table(&dir->header); |
1029 | if (new) | |
1030 | drop_sysctl_table(&new->header); | |
1031 | spin_unlock(&sysctl_lock); | |
1032 | return subdir; | |
1f87f0b5 EB |
1033 | } |
1034 | ||
0e47c99d EB |
1035 | static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) |
1036 | { | |
1037 | struct ctl_dir *parent; | |
1038 | const char *procname; | |
1039 | if (!dir->header.parent) | |
1040 | return &set->dir; | |
1041 | parent = xlate_dir(set, dir->header.parent); | |
1042 | if (IS_ERR(parent)) | |
1043 | return parent; | |
1044 | procname = dir->header.ctl_table[0].procname; | |
1045 | return find_subdir(parent, procname, strlen(procname)); | |
1046 | } | |
1047 | ||
1048 | static int sysctl_follow_link(struct ctl_table_header **phead, | |
13bcc6a2 | 1049 | struct ctl_table **pentry) |
0e47c99d EB |
1050 | { |
1051 | struct ctl_table_header *head; | |
1052 | struct ctl_table_root *root; | |
1053 | struct ctl_table_set *set; | |
1054 | struct ctl_table *entry; | |
1055 | struct ctl_dir *dir; | |
1056 | int ret; | |
1057 | ||
0e47c99d EB |
1058 | ret = 0; |
1059 | spin_lock(&sysctl_lock); | |
1060 | root = (*pentry)->data; | |
13bcc6a2 | 1061 | set = lookup_header_set(root); |
0e47c99d EB |
1062 | dir = xlate_dir(set, (*phead)->parent); |
1063 | if (IS_ERR(dir)) | |
1064 | ret = PTR_ERR(dir); | |
1065 | else { | |
1066 | const char *procname = (*pentry)->procname; | |
1067 | head = NULL; | |
1068 | entry = find_entry(&head, dir, procname, strlen(procname)); | |
1069 | ret = -ENOENT; | |
1070 | if (entry && use_table(head)) { | |
1071 | unuse_table(*phead); | |
1072 | *phead = head; | |
1073 | *pentry = entry; | |
1074 | ret = 0; | |
1075 | } | |
1076 | } | |
1077 | ||
1078 | spin_unlock(&sysctl_lock); | |
1079 | return ret; | |
1080 | } | |
1081 | ||
7c60c48f | 1082 | static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) |
1f87f0b5 | 1083 | { |
7c60c48f EB |
1084 | struct va_format vaf; |
1085 | va_list args; | |
1f87f0b5 | 1086 | |
7c60c48f EB |
1087 | va_start(args, fmt); |
1088 | vaf.fmt = fmt; | |
1089 | vaf.va = &args; | |
1090 | ||
87ebdc00 AM |
1091 | pr_err("sysctl table check failed: %s/%s %pV\n", |
1092 | path, table->procname, &vaf); | |
1f87f0b5 | 1093 | |
7c60c48f EB |
1094 | va_end(args); |
1095 | return -EINVAL; | |
1f87f0b5 EB |
1096 | } |
1097 | ||
4f2fec00 LR |
1098 | static int sysctl_check_table_array(const char *path, struct ctl_table *table) |
1099 | { | |
1100 | int err = 0; | |
1101 | ||
61d9b56a LR |
1102 | if ((table->proc_handler == proc_douintvec) || |
1103 | (table->proc_handler == proc_douintvec_minmax)) { | |
4f2fec00 | 1104 | if (table->maxlen != sizeof(unsigned int)) |
64a11f3d | 1105 | err |= sysctl_err(path, table, "array not allowed"); |
4f2fec00 LR |
1106 | } |
1107 | ||
1108 | return err; | |
1109 | } | |
1110 | ||
7c60c48f | 1111 | static int sysctl_check_table(const char *path, struct ctl_table *table) |
1f87f0b5 | 1112 | { |
7c60c48f | 1113 | int err = 0; |
1f87f0b5 | 1114 | for (; table->procname; table++) { |
1f87f0b5 | 1115 | if (table->child) |
89c5b53b | 1116 | err |= sysctl_err(path, table, "Not a file"); |
7c60c48f EB |
1117 | |
1118 | if ((table->proc_handler == proc_dostring) || | |
1119 | (table->proc_handler == proc_dointvec) || | |
1680a386 | 1120 | (table->proc_handler == proc_douintvec) || |
61d9b56a | 1121 | (table->proc_handler == proc_douintvec_minmax) || |
7c60c48f EB |
1122 | (table->proc_handler == proc_dointvec_minmax) || |
1123 | (table->proc_handler == proc_dointvec_jiffies) || | |
1124 | (table->proc_handler == proc_dointvec_userhz_jiffies) || | |
1125 | (table->proc_handler == proc_dointvec_ms_jiffies) || | |
1126 | (table->proc_handler == proc_doulongvec_minmax) || | |
1127 | (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { | |
1128 | if (!table->data) | |
89c5b53b | 1129 | err |= sysctl_err(path, table, "No data"); |
7c60c48f | 1130 | if (!table->maxlen) |
89c5b53b | 1131 | err |= sysctl_err(path, table, "No maxlen"); |
4f2fec00 LR |
1132 | else |
1133 | err |= sysctl_check_table_array(path, table); | |
7c60c48f EB |
1134 | } |
1135 | if (!table->proc_handler) | |
89c5b53b | 1136 | err |= sysctl_err(path, table, "No proc_handler"); |
7c60c48f EB |
1137 | |
1138 | if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) | |
89c5b53b | 1139 | err |= sysctl_err(path, table, "bogus .mode 0%o", |
7c60c48f | 1140 | table->mode); |
1f87f0b5 | 1141 | } |
7c60c48f | 1142 | return err; |
1f87f0b5 | 1143 | } |
1f87f0b5 | 1144 | |
0e47c99d EB |
1145 | static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, |
1146 | struct ctl_table_root *link_root) | |
1147 | { | |
1148 | struct ctl_table *link_table, *entry, *link; | |
1149 | struct ctl_table_header *links; | |
ac13ac6f | 1150 | struct ctl_node *node; |
0e47c99d EB |
1151 | char *link_name; |
1152 | int nr_entries, name_bytes; | |
1153 | ||
1154 | name_bytes = 0; | |
1155 | nr_entries = 0; | |
1156 | for (entry = table; entry->procname; entry++) { | |
1157 | nr_entries++; | |
1158 | name_bytes += strlen(entry->procname) + 1; | |
1159 | } | |
1160 | ||
1161 | links = kzalloc(sizeof(struct ctl_table_header) + | |
ac13ac6f | 1162 | sizeof(struct ctl_node)*nr_entries + |
0e47c99d EB |
1163 | sizeof(struct ctl_table)*(nr_entries + 1) + |
1164 | name_bytes, | |
1165 | GFP_KERNEL); | |
1166 | ||
1167 | if (!links) | |
1168 | return NULL; | |
1169 | ||
ac13ac6f EB |
1170 | node = (struct ctl_node *)(links + 1); |
1171 | link_table = (struct ctl_table *)(node + nr_entries); | |
0e47c99d EB |
1172 | link_name = (char *)&link_table[nr_entries + 1]; |
1173 | ||
1174 | for (link = link_table, entry = table; entry->procname; link++, entry++) { | |
1175 | int len = strlen(entry->procname) + 1; | |
1176 | memcpy(link_name, entry->procname, len); | |
1177 | link->procname = link_name; | |
1178 | link->mode = S_IFLNK|S_IRWXUGO; | |
1179 | link->data = link_root; | |
1180 | link_name += len; | |
1181 | } | |
ac13ac6f | 1182 | init_header(links, dir->header.root, dir->header.set, node, link_table); |
0e47c99d EB |
1183 | links->nreg = nr_entries; |
1184 | ||
1185 | return links; | |
1186 | } | |
1187 | ||
1188 | static bool get_links(struct ctl_dir *dir, | |
1189 | struct ctl_table *table, struct ctl_table_root *link_root) | |
1190 | { | |
1191 | struct ctl_table_header *head; | |
1192 | struct ctl_table *entry, *link; | |
1193 | ||
1194 | /* Are there links available for every entry in table? */ | |
1195 | for (entry = table; entry->procname; entry++) { | |
1196 | const char *procname = entry->procname; | |
1197 | link = find_entry(&head, dir, procname, strlen(procname)); | |
1198 | if (!link) | |
1199 | return false; | |
1200 | if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) | |
1201 | continue; | |
1202 | if (S_ISLNK(link->mode) && (link->data == link_root)) | |
1203 | continue; | |
1204 | return false; | |
1205 | } | |
1206 | ||
1207 | /* The checks passed. Increase the registration count on the links */ | |
1208 | for (entry = table; entry->procname; entry++) { | |
1209 | const char *procname = entry->procname; | |
1210 | link = find_entry(&head, dir, procname, strlen(procname)); | |
1211 | head->nreg++; | |
1212 | } | |
1213 | return true; | |
1214 | } | |
1215 | ||
1216 | static int insert_links(struct ctl_table_header *head) | |
1217 | { | |
1218 | struct ctl_table_set *root_set = &sysctl_table_root.default_set; | |
1219 | struct ctl_dir *core_parent = NULL; | |
1220 | struct ctl_table_header *links; | |
1221 | int err; | |
1222 | ||
1223 | if (head->set == root_set) | |
1224 | return 0; | |
1225 | ||
1226 | core_parent = xlate_dir(root_set, head->parent); | |
1227 | if (IS_ERR(core_parent)) | |
1228 | return 0; | |
1229 | ||
1230 | if (get_links(core_parent, head->ctl_table, head->root)) | |
1231 | return 0; | |
1232 | ||
1233 | core_parent->header.nreg++; | |
1234 | spin_unlock(&sysctl_lock); | |
1235 | ||
1236 | links = new_links(core_parent, head->ctl_table, head->root); | |
1237 | ||
1238 | spin_lock(&sysctl_lock); | |
1239 | err = -ENOMEM; | |
1240 | if (!links) | |
1241 | goto out; | |
1242 | ||
1243 | err = 0; | |
1244 | if (get_links(core_parent, head->ctl_table, head->root)) { | |
1245 | kfree(links); | |
1246 | goto out; | |
1247 | } | |
1248 | ||
1249 | err = insert_header(core_parent, links); | |
1250 | if (err) | |
1251 | kfree(links); | |
1252 | out: | |
1253 | drop_sysctl_table(&core_parent->header); | |
1254 | return err; | |
1255 | } | |
1256 | ||
1f87f0b5 | 1257 | /** |
f728019b | 1258 | * __register_sysctl_table - register a leaf sysctl table |
60a47a2e | 1259 | * @set: Sysctl tree to register on |
1f87f0b5 EB |
1260 | * @path: The path to the directory the sysctl table is in. |
1261 | * @table: the top-level table structure | |
1262 | * | |
1263 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1264 | * array. A completely 0 filled entry terminates the table. | |
1265 | * | |
1266 | * The members of the &struct ctl_table structure are used as follows: | |
1267 | * | |
1268 | * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not | |
1269 | * enter a sysctl file | |
1270 | * | |
1271 | * data - a pointer to data for use by proc_handler | |
1272 | * | |
1273 | * maxlen - the maximum size in bytes of the data | |
1274 | * | |
f728019b | 1275 | * mode - the file permissions for the /proc/sys file |
1f87f0b5 | 1276 | * |
f728019b | 1277 | * child - must be %NULL. |
1f87f0b5 EB |
1278 | * |
1279 | * proc_handler - the text handler routine (described below) | |
1280 | * | |
1f87f0b5 EB |
1281 | * extra1, extra2 - extra pointers usable by the proc handler routines |
1282 | * | |
1283 | * Leaf nodes in the sysctl tree will be represented by a single file | |
1284 | * under /proc; non-leaf nodes will be represented by directories. | |
1285 | * | |
f728019b EB |
1286 | * There must be a proc_handler routine for any terminal nodes. |
1287 | * Several default handlers are available to cover common cases - | |
1f87f0b5 EB |
1288 | * |
1289 | * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), | |
1290 | * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), | |
1291 | * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() | |
1292 | * | |
1293 | * It is the handler's job to read the input buffer from user memory | |
1294 | * and process it. The handler should return 0 on success. | |
1295 | * | |
1296 | * This routine returns %NULL on a failure to register, and a pointer | |
1297 | * to the table header on success. | |
1298 | */ | |
6e9d5164 | 1299 | struct ctl_table_header *__register_sysctl_table( |
60a47a2e | 1300 | struct ctl_table_set *set, |
6e9d5164 | 1301 | const char *path, struct ctl_table *table) |
1f87f0b5 | 1302 | { |
60a47a2e | 1303 | struct ctl_table_root *root = set->dir.header.root; |
1f87f0b5 | 1304 | struct ctl_table_header *header; |
6e9d5164 | 1305 | const char *name, *nextname; |
7ec66d06 | 1306 | struct ctl_dir *dir; |
ac13ac6f EB |
1307 | struct ctl_table *entry; |
1308 | struct ctl_node *node; | |
1309 | int nr_entries = 0; | |
1310 | ||
1311 | for (entry = table; entry->procname; entry++) | |
1312 | nr_entries++; | |
1f87f0b5 | 1313 | |
ac13ac6f EB |
1314 | header = kzalloc(sizeof(struct ctl_table_header) + |
1315 | sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); | |
1f87f0b5 EB |
1316 | if (!header) |
1317 | return NULL; | |
1318 | ||
ac13ac6f EB |
1319 | node = (struct ctl_node *)(header + 1); |
1320 | init_header(header, root, set, node, table); | |
7ec66d06 EB |
1321 | if (sysctl_check_table(path, table)) |
1322 | goto fail; | |
1323 | ||
1324 | spin_lock(&sysctl_lock); | |
0e47c99d | 1325 | dir = &set->dir; |
60f126d9 | 1326 | /* Reference moved down the diretory tree get_subdir */ |
7ec66d06 EB |
1327 | dir->header.nreg++; |
1328 | spin_unlock(&sysctl_lock); | |
1f87f0b5 | 1329 | |
7ec66d06 | 1330 | /* Find the directory for the ctl_table */ |
6e9d5164 EB |
1331 | for (name = path; name; name = nextname) { |
1332 | int namelen; | |
1333 | nextname = strchr(name, '/'); | |
1334 | if (nextname) { | |
1335 | namelen = nextname - name; | |
1336 | nextname++; | |
1337 | } else { | |
1338 | namelen = strlen(name); | |
1339 | } | |
1340 | if (namelen == 0) | |
1341 | continue; | |
1f87f0b5 | 1342 | |
0e47c99d | 1343 | dir = get_subdir(dir, name, namelen); |
7ec66d06 EB |
1344 | if (IS_ERR(dir)) |
1345 | goto fail; | |
1f87f0b5 | 1346 | } |
0e47c99d | 1347 | |
1f87f0b5 | 1348 | spin_lock(&sysctl_lock); |
0e47c99d | 1349 | if (insert_header(dir, header)) |
7ec66d06 | 1350 | goto fail_put_dir_locked; |
0e47c99d | 1351 | |
7ec66d06 | 1352 | drop_sysctl_table(&dir->header); |
1f87f0b5 EB |
1353 | spin_unlock(&sysctl_lock); |
1354 | ||
1355 | return header; | |
0e47c99d | 1356 | |
7ec66d06 EB |
1357 | fail_put_dir_locked: |
1358 | drop_sysctl_table(&dir->header); | |
7c60c48f EB |
1359 | spin_unlock(&sysctl_lock); |
1360 | fail: | |
1361 | kfree(header); | |
1362 | dump_stack(); | |
1363 | return NULL; | |
1f87f0b5 EB |
1364 | } |
1365 | ||
fea478d4 EB |
1366 | /** |
1367 | * register_sysctl - register a sysctl table | |
1368 | * @path: The path to the directory the sysctl table is in. | |
1369 | * @table: the table structure | |
1370 | * | |
1371 | * Register a sysctl table. @table should be a filled in ctl_table | |
1372 | * array. A completely 0 filled entry terminates the table. | |
1373 | * | |
1374 | * See __register_sysctl_table for more details. | |
1375 | */ | |
1376 | struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) | |
1377 | { | |
1378 | return __register_sysctl_table(&sysctl_table_root.default_set, | |
1379 | path, table); | |
1380 | } | |
1381 | EXPORT_SYMBOL(register_sysctl); | |
1382 | ||
6e9d5164 EB |
1383 | static char *append_path(const char *path, char *pos, const char *name) |
1384 | { | |
1385 | int namelen; | |
1386 | namelen = strlen(name); | |
1387 | if (((pos - path) + namelen + 2) >= PATH_MAX) | |
1388 | return NULL; | |
1389 | memcpy(pos, name, namelen); | |
1390 | pos[namelen] = '/'; | |
1391 | pos[namelen + 1] = '\0'; | |
1392 | pos += namelen + 1; | |
1393 | return pos; | |
1394 | } | |
1395 | ||
f728019b EB |
1396 | static int count_subheaders(struct ctl_table *table) |
1397 | { | |
1398 | int has_files = 0; | |
1399 | int nr_subheaders = 0; | |
1400 | struct ctl_table *entry; | |
1401 | ||
1402 | /* special case: no directory and empty directory */ | |
1403 | if (!table || !table->procname) | |
1404 | return 1; | |
1405 | ||
1406 | for (entry = table; entry->procname; entry++) { | |
1407 | if (entry->child) | |
1408 | nr_subheaders += count_subheaders(entry->child); | |
1409 | else | |
1410 | has_files = 1; | |
1411 | } | |
1412 | return nr_subheaders + has_files; | |
1413 | } | |
1414 | ||
1415 | static int register_leaf_sysctl_tables(const char *path, char *pos, | |
60a47a2e | 1416 | struct ctl_table_header ***subheader, struct ctl_table_set *set, |
f728019b EB |
1417 | struct ctl_table *table) |
1418 | { | |
1419 | struct ctl_table *ctl_table_arg = NULL; | |
1420 | struct ctl_table *entry, *files; | |
1421 | int nr_files = 0; | |
1422 | int nr_dirs = 0; | |
1423 | int err = -ENOMEM; | |
1424 | ||
1425 | for (entry = table; entry->procname; entry++) { | |
1426 | if (entry->child) | |
1427 | nr_dirs++; | |
1428 | else | |
1429 | nr_files++; | |
1430 | } | |
1431 | ||
1432 | files = table; | |
1433 | /* If there are mixed files and directories we need a new table */ | |
1434 | if (nr_dirs && nr_files) { | |
1435 | struct ctl_table *new; | |
6396bb22 | 1436 | files = kcalloc(nr_files + 1, sizeof(struct ctl_table), |
f728019b EB |
1437 | GFP_KERNEL); |
1438 | if (!files) | |
1439 | goto out; | |
1440 | ||
1441 | ctl_table_arg = files; | |
1442 | for (new = files, entry = table; entry->procname; entry++) { | |
1443 | if (entry->child) | |
1444 | continue; | |
1445 | *new = *entry; | |
1446 | new++; | |
1447 | } | |
1448 | } | |
1449 | ||
1450 | /* Register everything except a directory full of subdirectories */ | |
1451 | if (nr_files || !nr_dirs) { | |
1452 | struct ctl_table_header *header; | |
60a47a2e | 1453 | header = __register_sysctl_table(set, path, files); |
f728019b EB |
1454 | if (!header) { |
1455 | kfree(ctl_table_arg); | |
1456 | goto out; | |
1457 | } | |
1458 | ||
1459 | /* Remember if we need to free the file table */ | |
1460 | header->ctl_table_arg = ctl_table_arg; | |
1461 | **subheader = header; | |
1462 | (*subheader)++; | |
1463 | } | |
1464 | ||
1465 | /* Recurse into the subdirectories. */ | |
1466 | for (entry = table; entry->procname; entry++) { | |
1467 | char *child_pos; | |
1468 | ||
1469 | if (!entry->child) | |
1470 | continue; | |
1471 | ||
1472 | err = -ENAMETOOLONG; | |
1473 | child_pos = append_path(path, pos, entry->procname); | |
1474 | if (!child_pos) | |
1475 | goto out; | |
1476 | ||
1477 | err = register_leaf_sysctl_tables(path, child_pos, subheader, | |
60a47a2e | 1478 | set, entry->child); |
f728019b EB |
1479 | pos[0] = '\0'; |
1480 | if (err) | |
1481 | goto out; | |
1482 | } | |
1483 | err = 0; | |
1484 | out: | |
1485 | /* On failure our caller will unregister all registered subheaders */ | |
1486 | return err; | |
1487 | } | |
1488 | ||
6e9d5164 EB |
1489 | /** |
1490 | * __register_sysctl_paths - register a sysctl table hierarchy | |
60a47a2e | 1491 | * @set: Sysctl tree to register on |
6e9d5164 EB |
1492 | * @path: The path to the directory the sysctl table is in. |
1493 | * @table: the top-level table structure | |
1494 | * | |
1495 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1496 | * array. A completely 0 filled entry terminates the table. | |
1497 | * | |
1498 | * See __register_sysctl_table for more details. | |
1499 | */ | |
1500 | struct ctl_table_header *__register_sysctl_paths( | |
60a47a2e | 1501 | struct ctl_table_set *set, |
6e9d5164 EB |
1502 | const struct ctl_path *path, struct ctl_table *table) |
1503 | { | |
ec6a5266 | 1504 | struct ctl_table *ctl_table_arg = table; |
f728019b EB |
1505 | int nr_subheaders = count_subheaders(table); |
1506 | struct ctl_table_header *header = NULL, **subheaders, **subheader; | |
6e9d5164 EB |
1507 | const struct ctl_path *component; |
1508 | char *new_path, *pos; | |
1509 | ||
1510 | pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); | |
1511 | if (!new_path) | |
1512 | return NULL; | |
1513 | ||
1514 | pos[0] = '\0'; | |
1515 | for (component = path; component->procname; component++) { | |
1516 | pos = append_path(new_path, pos, component->procname); | |
1517 | if (!pos) | |
1518 | goto out; | |
1519 | } | |
ec6a5266 EB |
1520 | while (table->procname && table->child && !table[1].procname) { |
1521 | pos = append_path(new_path, pos, table->procname); | |
1522 | if (!pos) | |
1523 | goto out; | |
1524 | table = table->child; | |
1525 | } | |
f728019b | 1526 | if (nr_subheaders == 1) { |
60a47a2e | 1527 | header = __register_sysctl_table(set, new_path, table); |
f728019b EB |
1528 | if (header) |
1529 | header->ctl_table_arg = ctl_table_arg; | |
1530 | } else { | |
1531 | header = kzalloc(sizeof(*header) + | |
1532 | sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); | |
1533 | if (!header) | |
1534 | goto out; | |
1535 | ||
1536 | subheaders = (struct ctl_table_header **) (header + 1); | |
1537 | subheader = subheaders; | |
ec6a5266 | 1538 | header->ctl_table_arg = ctl_table_arg; |
f728019b EB |
1539 | |
1540 | if (register_leaf_sysctl_tables(new_path, pos, &subheader, | |
60a47a2e | 1541 | set, table)) |
f728019b EB |
1542 | goto err_register_leaves; |
1543 | } | |
1544 | ||
6e9d5164 EB |
1545 | out: |
1546 | kfree(new_path); | |
1547 | return header; | |
f728019b EB |
1548 | |
1549 | err_register_leaves: | |
1550 | while (subheader > subheaders) { | |
1551 | struct ctl_table_header *subh = *(--subheader); | |
1552 | struct ctl_table *table = subh->ctl_table_arg; | |
1553 | unregister_sysctl_table(subh); | |
1554 | kfree(table); | |
1555 | } | |
1556 | kfree(header); | |
1557 | header = NULL; | |
1558 | goto out; | |
6e9d5164 EB |
1559 | } |
1560 | ||
1f87f0b5 EB |
1561 | /** |
1562 | * register_sysctl_table_path - register a sysctl table hierarchy | |
1563 | * @path: The path to the directory the sysctl table is in. | |
1564 | * @table: the top-level table structure | |
1565 | * | |
1566 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1567 | * array. A completely 0 filled entry terminates the table. | |
1568 | * | |
1569 | * See __register_sysctl_paths for more details. | |
1570 | */ | |
1571 | struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, | |
1572 | struct ctl_table *table) | |
1573 | { | |
60a47a2e | 1574 | return __register_sysctl_paths(&sysctl_table_root.default_set, |
1f87f0b5 EB |
1575 | path, table); |
1576 | } | |
1577 | EXPORT_SYMBOL(register_sysctl_paths); | |
1578 | ||
1579 | /** | |
1580 | * register_sysctl_table - register a sysctl table hierarchy | |
1581 | * @table: the top-level table structure | |
1582 | * | |
1583 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1584 | * array. A completely 0 filled entry terminates the table. | |
1585 | * | |
1586 | * See register_sysctl_paths for more details. | |
1587 | */ | |
1588 | struct ctl_table_header *register_sysctl_table(struct ctl_table *table) | |
1589 | { | |
1590 | static const struct ctl_path null_path[] = { {} }; | |
1591 | ||
1592 | return register_sysctl_paths(null_path, table); | |
1593 | } | |
1594 | EXPORT_SYMBOL(register_sysctl_table); | |
1595 | ||
0e47c99d EB |
1596 | static void put_links(struct ctl_table_header *header) |
1597 | { | |
1598 | struct ctl_table_set *root_set = &sysctl_table_root.default_set; | |
1599 | struct ctl_table_root *root = header->root; | |
1600 | struct ctl_dir *parent = header->parent; | |
1601 | struct ctl_dir *core_parent; | |
1602 | struct ctl_table *entry; | |
1603 | ||
1604 | if (header->set == root_set) | |
1605 | return; | |
1606 | ||
1607 | core_parent = xlate_dir(root_set, parent); | |
1608 | if (IS_ERR(core_parent)) | |
1609 | return; | |
1610 | ||
1611 | for (entry = header->ctl_table; entry->procname; entry++) { | |
1612 | struct ctl_table_header *link_head; | |
1613 | struct ctl_table *link; | |
1614 | const char *name = entry->procname; | |
1615 | ||
1616 | link = find_entry(&link_head, core_parent, name, strlen(name)); | |
1617 | if (link && | |
1618 | ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || | |
1619 | (S_ISLNK(link->mode) && (link->data == root)))) { | |
1620 | drop_sysctl_table(link_head); | |
1621 | } | |
1622 | else { | |
87ebdc00 | 1623 | pr_err("sysctl link missing during unregister: "); |
0e47c99d | 1624 | sysctl_print_dir(parent); |
87ebdc00 | 1625 | pr_cont("/%s\n", name); |
0e47c99d EB |
1626 | } |
1627 | } | |
1628 | } | |
1629 | ||
938aaa4f EB |
1630 | static void drop_sysctl_table(struct ctl_table_header *header) |
1631 | { | |
7ec66d06 EB |
1632 | struct ctl_dir *parent = header->parent; |
1633 | ||
938aaa4f EB |
1634 | if (--header->nreg) |
1635 | return; | |
1636 | ||
89189557 | 1637 | if (parent) { |
23da9588 | 1638 | put_links(header); |
89189557 Y |
1639 | start_unregistering(header); |
1640 | } | |
1641 | ||
938aaa4f EB |
1642 | if (!--header->count) |
1643 | kfree_rcu(header, rcu); | |
7ec66d06 EB |
1644 | |
1645 | if (parent) | |
1646 | drop_sysctl_table(&parent->header); | |
938aaa4f EB |
1647 | } |
1648 | ||
1f87f0b5 EB |
1649 | /** |
1650 | * unregister_sysctl_table - unregister a sysctl table hierarchy | |
1651 | * @header: the header returned from register_sysctl_table | |
1652 | * | |
1653 | * Unregisters the sysctl table and all children. proc entries may not | |
1654 | * actually be removed until they are no longer used by anyone. | |
1655 | */ | |
1656 | void unregister_sysctl_table(struct ctl_table_header * header) | |
1657 | { | |
f728019b | 1658 | int nr_subheaders; |
1f87f0b5 EB |
1659 | might_sleep(); |
1660 | ||
1661 | if (header == NULL) | |
1662 | return; | |
1663 | ||
f728019b EB |
1664 | nr_subheaders = count_subheaders(header->ctl_table_arg); |
1665 | if (unlikely(nr_subheaders > 1)) { | |
1666 | struct ctl_table_header **subheaders; | |
1667 | int i; | |
1668 | ||
1669 | subheaders = (struct ctl_table_header **)(header + 1); | |
1670 | for (i = nr_subheaders -1; i >= 0; i--) { | |
1671 | struct ctl_table_header *subh = subheaders[i]; | |
1672 | struct ctl_table *table = subh->ctl_table_arg; | |
1673 | unregister_sysctl_table(subh); | |
1674 | kfree(table); | |
1675 | } | |
1676 | kfree(header); | |
1677 | return; | |
1678 | } | |
1679 | ||
1f87f0b5 | 1680 | spin_lock(&sysctl_lock); |
938aaa4f | 1681 | drop_sysctl_table(header); |
1f87f0b5 EB |
1682 | spin_unlock(&sysctl_lock); |
1683 | } | |
1684 | EXPORT_SYMBOL(unregister_sysctl_table); | |
1685 | ||
0e47c99d | 1686 | void setup_sysctl_set(struct ctl_table_set *set, |
9eb47c26 | 1687 | struct ctl_table_root *root, |
1f87f0b5 EB |
1688 | int (*is_seen)(struct ctl_table_set *)) |
1689 | { | |
1347440d | 1690 | memset(set, 0, sizeof(*set)); |
0e47c99d | 1691 | set->is_seen = is_seen; |
ac13ac6f | 1692 | init_header(&set->dir.header, root, set, NULL, root_table); |
1f87f0b5 EB |
1693 | } |
1694 | ||
97324cd8 EB |
1695 | void retire_sysctl_set(struct ctl_table_set *set) |
1696 | { | |
ac13ac6f | 1697 | WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); |
97324cd8 | 1698 | } |
1f87f0b5 | 1699 | |
1e0edd3f | 1700 | int __init proc_sys_init(void) |
77b14db5 | 1701 | { |
e1675231 AD |
1702 | struct proc_dir_entry *proc_sys_root; |
1703 | ||
77b14db5 | 1704 | proc_sys_root = proc_mkdir("sys", NULL); |
9043476f | 1705 | proc_sys_root->proc_iops = &proc_sys_dir_operations; |
d56c0d45 | 1706 | proc_sys_root->proc_dir_ops = &proc_sys_dir_file_operations; |
77b14db5 | 1707 | proc_sys_root->nlink = 0; |
de4e83bd EB |
1708 | |
1709 | return sysctl_init(); | |
77b14db5 | 1710 | } |
3db978d4 | 1711 | |
0a477e1a VB |
1712 | struct sysctl_alias { |
1713 | const char *kernel_param; | |
1714 | const char *sysctl_param; | |
1715 | }; | |
1716 | ||
1717 | /* | |
1718 | * Historically some settings had both sysctl and a command line parameter. | |
1719 | * With the generic sysctl. parameter support, we can handle them at a single | |
1720 | * place and only keep the historical name for compatibility. This is not meant | |
1721 | * to add brand new aliases. When adding existing aliases, consider whether | |
1722 | * the possibly different moment of changing the value (e.g. from early_param | |
1723 | * to the moment do_sysctl_args() is called) is an issue for the specific | |
1724 | * parameter. | |
1725 | */ | |
1726 | static const struct sysctl_alias sysctl_aliases[] = { | |
f117955a GP |
1727 | {"hardlockup_all_cpu_backtrace", "kernel.hardlockup_all_cpu_backtrace" }, |
1728 | {"hung_task_panic", "kernel.hung_task_panic" }, | |
1729 | {"numa_zonelist_order", "vm.numa_zonelist_order" }, | |
1730 | {"softlockup_all_cpu_backtrace", "kernel.softlockup_all_cpu_backtrace" }, | |
1731 | {"softlockup_panic", "kernel.softlockup_panic" }, | |
0a477e1a VB |
1732 | { } |
1733 | }; | |
1734 | ||
1735 | static const char *sysctl_find_alias(char *param) | |
1736 | { | |
1737 | const struct sysctl_alias *alias; | |
1738 | ||
1739 | for (alias = &sysctl_aliases[0]; alias->kernel_param != NULL; alias++) { | |
1740 | if (strcmp(alias->kernel_param, param) == 0) | |
1741 | return alias->sysctl_param; | |
1742 | } | |
1743 | ||
1744 | return NULL; | |
1745 | } | |
1746 | ||
3db978d4 VB |
1747 | /* Set sysctl value passed on kernel command line. */ |
1748 | static int process_sysctl_arg(char *param, char *val, | |
1749 | const char *unused, void *arg) | |
1750 | { | |
1751 | char *path; | |
1752 | struct vfsmount **proc_mnt = arg; | |
1753 | struct file_system_type *proc_fs_type; | |
1754 | struct file *file; | |
1755 | int len; | |
1756 | int err; | |
1757 | loff_t pos = 0; | |
1758 | ssize_t wret; | |
1759 | ||
0a477e1a VB |
1760 | if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) { |
1761 | param += sizeof("sysctl") - 1; | |
3db978d4 | 1762 | |
0a477e1a VB |
1763 | if (param[0] != '/' && param[0] != '.') |
1764 | return 0; | |
3db978d4 | 1765 | |
0a477e1a VB |
1766 | param++; |
1767 | } else { | |
1768 | param = (char *) sysctl_find_alias(param); | |
1769 | if (!param) | |
1770 | return 0; | |
1771 | } | |
3db978d4 VB |
1772 | |
1773 | /* | |
1774 | * To set sysctl options, we use a temporary mount of proc, look up the | |
1775 | * respective sys/ file and write to it. To avoid mounting it when no | |
1776 | * options were given, we mount it only when the first sysctl option is | |
1777 | * found. Why not a persistent mount? There are problems with a | |
1778 | * persistent mount of proc in that it forces userspace not to use any | |
1779 | * proc mount options. | |
1780 | */ | |
1781 | if (!*proc_mnt) { | |
1782 | proc_fs_type = get_fs_type("proc"); | |
1783 | if (!proc_fs_type) { | |
1784 | pr_err("Failed to find procfs to set sysctl from command line\n"); | |
1785 | return 0; | |
1786 | } | |
1787 | *proc_mnt = kern_mount(proc_fs_type); | |
1788 | put_filesystem(proc_fs_type); | |
1789 | if (IS_ERR(*proc_mnt)) { | |
1790 | pr_err("Failed to mount procfs to set sysctl from command line\n"); | |
1791 | return 0; | |
1792 | } | |
1793 | } | |
1794 | ||
1795 | path = kasprintf(GFP_KERNEL, "sys/%s", param); | |
1796 | if (!path) | |
1797 | panic("%s: Failed to allocate path for %s\n", __func__, param); | |
1798 | strreplace(path, '.', '/'); | |
1799 | ||
1800 | file = file_open_root((*proc_mnt)->mnt_root, *proc_mnt, path, O_WRONLY, 0); | |
1801 | if (IS_ERR(file)) { | |
1802 | err = PTR_ERR(file); | |
1803 | if (err == -ENOENT) | |
1804 | pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n", | |
1805 | param, val); | |
1806 | else if (err == -EACCES) | |
1807 | pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n", | |
1808 | param, val); | |
1809 | else | |
1810 | pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n", | |
1811 | file, param, val); | |
1812 | goto out; | |
1813 | } | |
1814 | len = strlen(val); | |
1815 | wret = kernel_write(file, val, len, &pos); | |
1816 | if (wret < 0) { | |
1817 | err = wret; | |
1818 | if (err == -EINVAL) | |
1819 | pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n", | |
1820 | param, val); | |
1821 | else | |
1822 | pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n", | |
1823 | ERR_PTR(err), param, val); | |
1824 | } else if (wret != len) { | |
1825 | pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n", | |
1826 | wret, len, path, param, val); | |
1827 | } | |
1828 | ||
1829 | err = filp_close(file, NULL); | |
1830 | if (err) | |
1831 | pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n", | |
1832 | ERR_PTR(err), param, val); | |
1833 | out: | |
1834 | kfree(path); | |
1835 | return 0; | |
1836 | } | |
1837 | ||
1838 | void do_sysctl_args(void) | |
1839 | { | |
1840 | char *command_line; | |
1841 | struct vfsmount *proc_mnt = NULL; | |
1842 | ||
1843 | command_line = kstrdup(saved_command_line, GFP_KERNEL); | |
1844 | if (!command_line) | |
1845 | panic("%s: Failed to allocate copy of command line\n", __func__); | |
1846 | ||
1847 | parse_args("Setting sysctl args", command_line, | |
1848 | NULL, 0, -1, -1, &proc_mnt, process_sysctl_arg); | |
1849 | ||
1850 | if (proc_mnt) | |
1851 | kern_unmount(proc_mnt); | |
1852 | ||
1853 | kfree(command_line); | |
1854 | } |