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