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