1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved 4 * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org> 5 * Copyright 2001-2006 Ian Kent <raven@themaw.net> 6 */ 7 8#include <linux/capability.h> 9#include <linux/compat.h> 10 11#include "autofs_i.h" 12 13static int autofs_dir_permission(struct mnt_idmap *, struct inode *, int); 14static int autofs_dir_symlink(struct mnt_idmap *, struct inode *, 15 struct dentry *, const char *); 16static int autofs_dir_unlink(struct inode *, struct dentry *); 17static int autofs_dir_rmdir(struct inode *, struct dentry *); 18static int autofs_dir_mkdir(struct mnt_idmap *, struct inode *, 19 struct dentry *, umode_t); 20static long autofs_root_ioctl(struct file *, unsigned int, unsigned long); 21#ifdef CONFIG_COMPAT 22static long autofs_root_compat_ioctl(struct file *, 23 unsigned int, unsigned long); 24#endif 25static int autofs_dir_open(struct inode *inode, struct file *file); 26static struct dentry *autofs_lookup(struct inode *, 27 struct dentry *, unsigned int); 28static struct vfsmount *autofs_d_automount(struct path *); 29static int autofs_d_manage(const struct path *, bool); 30static void autofs_dentry_release(struct dentry *); 31 32const struct file_operations autofs_root_operations = { 33 .open = dcache_dir_open, 34 .release = dcache_dir_close, 35 .read = generic_read_dir, 36 .iterate_shared = dcache_readdir, 37 .llseek = dcache_dir_lseek, 38 .unlocked_ioctl = autofs_root_ioctl, 39#ifdef CONFIG_COMPAT 40 .compat_ioctl = autofs_root_compat_ioctl, 41#endif 42}; 43 44const struct file_operations autofs_dir_operations = { 45 .open = autofs_dir_open, 46 .release = dcache_dir_close, 47 .read = generic_read_dir, 48 .iterate_shared = dcache_readdir, 49 .llseek = dcache_dir_lseek, 50}; 51 52const struct inode_operations autofs_dir_inode_operations = { 53 .lookup = autofs_lookup, 54 .permission = autofs_dir_permission, 55 .unlink = autofs_dir_unlink, 56 .symlink = autofs_dir_symlink, 57 .mkdir = autofs_dir_mkdir, 58 .rmdir = autofs_dir_rmdir, 59}; 60 61const struct dentry_operations autofs_dentry_operations = { 62 .d_automount = autofs_d_automount, 63 .d_manage = autofs_d_manage, 64 .d_release = autofs_dentry_release, 65}; 66 67static void autofs_del_active(struct dentry *dentry) 68{ 69 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 70 struct autofs_info *ino; 71 72 ino = autofs_dentry_ino(dentry); 73 spin_lock(&sbi->lookup_lock); 74 list_del_init(&ino->active); 75 spin_unlock(&sbi->lookup_lock); 76} 77 78static int autofs_dir_open(struct inode *inode, struct file *file) 79{ 80 struct dentry *dentry = file->f_path.dentry; 81 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 82 struct autofs_info *ino = autofs_dentry_ino(dentry); 83 84 pr_debug("file=%p dentry=%p %pd\n", file, dentry, dentry); 85 86 if (autofs_oz_mode(sbi)) 87 goto out; 88 89 /* 90 * An empty directory in an autofs file system is always a 91 * mount point. The daemon must have failed to mount this 92 * during lookup so it doesn't exist. This can happen, for 93 * example, if user space returns an incorrect status for a 94 * mount request. Otherwise we're doing a readdir on the 95 * autofs file system so just let the libfs routines handle 96 * it. 97 */ 98 spin_lock(&sbi->lookup_lock); 99 if (!path_is_mountpoint(&file->f_path) && autofs_empty(ino)) { 100 spin_unlock(&sbi->lookup_lock); 101 return -ENOENT; 102 } 103 spin_unlock(&sbi->lookup_lock); 104 105out: 106 return dcache_dir_open(inode, file); 107} 108 109static void autofs_dentry_release(struct dentry *de) 110{ 111 struct autofs_info *ino = autofs_dentry_ino(de); 112 struct autofs_sb_info *sbi = autofs_sbi(de->d_sb); 113 114 pr_debug("releasing %p\n", de); 115 116 if (!ino) 117 return; 118 119 if (sbi) { 120 spin_lock(&sbi->lookup_lock); 121 if (!list_empty(&ino->active)) 122 list_del(&ino->active); 123 if (!list_empty(&ino->expiring)) 124 list_del(&ino->expiring); 125 spin_unlock(&sbi->lookup_lock); 126 } 127 128 autofs_free_ino(ino); 129} 130 131static struct dentry *autofs_lookup_active(struct dentry *dentry) 132{ 133 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 134 struct dentry *parent = dentry->d_parent; 135 const struct qstr *name = &dentry->d_name; 136 unsigned int len = name->len; 137 unsigned int hash = name->hash; 138 const unsigned char *str = name->name; 139 struct list_head *p, *head; 140 141 head = &sbi->active_list; 142 if (list_empty(head)) 143 return NULL; 144 spin_lock(&sbi->lookup_lock); 145 list_for_each(p, head) { 146 struct autofs_info *ino; 147 struct dentry *active; 148 const struct qstr *qstr; 149 150 ino = list_entry(p, struct autofs_info, active); 151 active = ino->dentry; 152 153 spin_lock(&active->d_lock); 154 155 /* Already gone? */ 156 if ((int) d_count(active) <= 0) 157 goto next; 158 159 qstr = &active->d_name; 160 161 if (active->d_name.hash != hash) 162 goto next; 163 if (active->d_parent != parent) 164 goto next; 165 166 if (qstr->len != len) 167 goto next; 168 if (memcmp(qstr->name, str, len)) 169 goto next; 170 171 if (d_unhashed(active)) { 172 dget_dlock(active); 173 spin_unlock(&active->d_lock); 174 spin_unlock(&sbi->lookup_lock); 175 return active; 176 } 177next: 178 spin_unlock(&active->d_lock); 179 } 180 spin_unlock(&sbi->lookup_lock); 181 182 return NULL; 183} 184 185static struct dentry *autofs_lookup_expiring(struct dentry *dentry, 186 bool rcu_walk) 187{ 188 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 189 struct dentry *parent = dentry->d_parent; 190 const struct qstr *name = &dentry->d_name; 191 unsigned int len = name->len; 192 unsigned int hash = name->hash; 193 const unsigned char *str = name->name; 194 struct list_head *p, *head; 195 196 head = &sbi->expiring_list; 197 if (list_empty(head)) 198 return NULL; 199 spin_lock(&sbi->lookup_lock); 200 list_for_each(p, head) { 201 struct autofs_info *ino; 202 struct dentry *expiring; 203 const struct qstr *qstr; 204 205 if (rcu_walk) { 206 spin_unlock(&sbi->lookup_lock); 207 return ERR_PTR(-ECHILD); 208 } 209 210 ino = list_entry(p, struct autofs_info, expiring); 211 expiring = ino->dentry; 212 213 spin_lock(&expiring->d_lock); 214 215 /* We've already been dentry_iput or unlinked */ 216 if (d_really_is_negative(expiring)) 217 goto next; 218 219 qstr = &expiring->d_name; 220 221 if (expiring->d_name.hash != hash) 222 goto next; 223 if (expiring->d_parent != parent) 224 goto next; 225 226 if (qstr->len != len) 227 goto next; 228 if (memcmp(qstr->name, str, len)) 229 goto next; 230 231 if (d_unhashed(expiring)) { 232 dget_dlock(expiring); 233 spin_unlock(&expiring->d_lock); 234 spin_unlock(&sbi->lookup_lock); 235 return expiring; 236 } 237next: 238 spin_unlock(&expiring->d_lock); 239 } 240 spin_unlock(&sbi->lookup_lock); 241 242 return NULL; 243} 244 245static int autofs_mount_wait(const struct path *path, bool rcu_walk) 246{ 247 struct autofs_sb_info *sbi = autofs_sbi(path->dentry->d_sb); 248 struct autofs_info *ino = autofs_dentry_ino(path->dentry); 249 int status = 0; 250 251 if (ino->flags & AUTOFS_INF_PENDING) { 252 if (rcu_walk) 253 return -ECHILD; 254 pr_debug("waiting for mount name=%pd\n", path->dentry); 255 status = autofs_wait(sbi, path, NFY_MOUNT); 256 pr_debug("mount wait done status=%d\n", status); 257 ino->last_used = jiffies; 258 return status; 259 } 260 if (!(sbi->flags & AUTOFS_SBI_STRICTEXPIRE)) 261 ino->last_used = jiffies; 262 return status; 263} 264 265static int do_expire_wait(const struct path *path, bool rcu_walk) 266{ 267 struct dentry *dentry = path->dentry; 268 struct dentry *expiring; 269 270 expiring = autofs_lookup_expiring(dentry, rcu_walk); 271 if (IS_ERR(expiring)) 272 return PTR_ERR(expiring); 273 if (!expiring) 274 return autofs_expire_wait(path, rcu_walk); 275 else { 276 const struct path this = { .mnt = path->mnt, .dentry = expiring }; 277 /* 278 * If we are racing with expire the request might not 279 * be quite complete, but the directory has been removed 280 * so it must have been successful, just wait for it. 281 */ 282 autofs_expire_wait(&this, 0); 283 autofs_del_expiring(expiring); 284 dput(expiring); 285 } 286 return 0; 287} 288 289static struct dentry *autofs_mountpoint_changed(struct path *path) 290{ 291 struct dentry *dentry = path->dentry; 292 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 293 294 /* If this is an indirect mount the dentry could have gone away 295 * and a new one created. 296 * 297 * This is unusual and I can't remember the case for which it 298 * was originally added now. But an example of how this can 299 * happen is an autofs indirect mount that has the "browse" 300 * option set and also has the "symlink" option in the autofs 301 * map entry. In this case the daemon will remove the browse 302 * directory and create a symlink as the mount leaving the 303 * struct path stale. 304 * 305 * Another not so obvious case is when a mount in an autofs 306 * indirect mount that uses the "nobrowse" option is being 307 * expired at the same time as a path walk. If the mount has 308 * been umounted but the mount point directory seen before 309 * becoming unhashed (during a lockless path walk) when a stat 310 * family system call is made the mount won't be re-mounted as 311 * it should. In this case the mount point that's been removed 312 * (by the daemon) will be stale and the a new mount point 313 * dentry created. 314 */ 315 if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) { 316 struct dentry *parent = dentry->d_parent; 317 struct autofs_info *ino; 318 struct dentry *new; 319 320 new = d_lookup(parent, &dentry->d_name); 321 if (!new) 322 return NULL; 323 ino = autofs_dentry_ino(new); 324 ino->last_used = jiffies; 325 dput(path->dentry); 326 path->dentry = new; 327 } 328 return path->dentry; 329} 330 331static struct vfsmount *autofs_d_automount(struct path *path) 332{ 333 struct dentry *dentry = path->dentry; 334 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 335 struct autofs_info *ino = autofs_dentry_ino(dentry); 336 int status; 337 338 pr_debug("dentry=%p %pd\n", dentry, dentry); 339 340 /* The daemon never triggers a mount. */ 341 if (autofs_oz_mode(sbi)) 342 return NULL; 343 344 /* 345 * If an expire request is pending everyone must wait. 346 * If the expire fails we're still mounted so continue 347 * the follow and return. A return of -EAGAIN (which only 348 * happens with indirect mounts) means the expire completed 349 * and the directory was removed, so just go ahead and try 350 * the mount. 351 */ 352 status = do_expire_wait(path, 0); 353 if (status && status != -EAGAIN) 354 return NULL; 355 356 /* Callback to the daemon to perform the mount or wait */ 357 spin_lock(&sbi->fs_lock); 358 if (ino->flags & AUTOFS_INF_PENDING) { 359 spin_unlock(&sbi->fs_lock); 360 status = autofs_mount_wait(path, 0); 361 if (status) 362 return ERR_PTR(status); 363 goto done; 364 } 365 366 /* 367 * If the dentry is a symlink it's equivalent to a directory 368 * having path_is_mountpoint() true, so there's no need to call 369 * back to the daemon. 370 */ 371 if (d_really_is_positive(dentry) && d_is_symlink(dentry)) { 372 spin_unlock(&sbi->fs_lock); 373 goto done; 374 } 375 376 if (!path_is_mountpoint(path)) { 377 /* 378 * It's possible that user space hasn't removed directories 379 * after umounting a rootless multi-mount, although it 380 * should. For v5 path_has_submounts() is sufficient to 381 * handle this because the leaves of the directory tree under 382 * the mount never trigger mounts themselves (they have an 383 * autofs trigger mount mounted on them). But v4 pseudo direct 384 * mounts do need the leaves to trigger mounts. In this case 385 * we have no choice but to use the autofs_empty() check and 386 * require user space behave. 387 */ 388 if (sbi->version > 4) { 389 if (path_has_submounts(path)) { 390 spin_unlock(&sbi->fs_lock); 391 goto done; 392 } 393 } else { 394 if (!autofs_empty(ino)) { 395 spin_unlock(&sbi->fs_lock); 396 goto done; 397 } 398 } 399 ino->flags |= AUTOFS_INF_PENDING; 400 spin_unlock(&sbi->fs_lock); 401 status = autofs_mount_wait(path, 0); 402 spin_lock(&sbi->fs_lock); 403 ino->flags &= ~AUTOFS_INF_PENDING; 404 if (status) { 405 spin_unlock(&sbi->fs_lock); 406 return ERR_PTR(status); 407 } 408 } 409 spin_unlock(&sbi->fs_lock); 410done: 411 /* Mount succeeded, check if we ended up with a new dentry */ 412 dentry = autofs_mountpoint_changed(path); 413 if (!dentry) 414 return ERR_PTR(-ENOENT); 415 416 return NULL; 417} 418 419static int autofs_d_manage(const struct path *path, bool rcu_walk) 420{ 421 struct dentry *dentry = path->dentry; 422 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 423 struct autofs_info *ino = autofs_dentry_ino(dentry); 424 int status; 425 426 pr_debug("dentry=%p %pd\n", dentry, dentry); 427 428 /* The daemon never waits. */ 429 if (autofs_oz_mode(sbi)) { 430 if (!path_is_mountpoint(path)) 431 return -EISDIR; 432 return 0; 433 } 434 435 /* Wait for pending expires */ 436 if (do_expire_wait(path, rcu_walk) == -ECHILD) 437 return -ECHILD; 438 439 /* 440 * This dentry may be under construction so wait on mount 441 * completion. 442 */ 443 status = autofs_mount_wait(path, rcu_walk); 444 if (status) 445 return status; 446 447 if (rcu_walk) { 448 /* We don't need fs_lock in rcu_walk mode, 449 * just testing 'AUTOFS_INF_WANT_EXPIRE' is enough. 450 * 451 * We only return -EISDIR when certain this isn't 452 * a mount-trap. 453 */ 454 struct inode *inode; 455 456 if (ino->flags & AUTOFS_INF_WANT_EXPIRE) 457 return 0; 458 if (path_is_mountpoint(path)) 459 return 0; 460 inode = d_inode_rcu(dentry); 461 if (inode && S_ISLNK(inode->i_mode)) 462 return -EISDIR; 463 if (!autofs_empty(ino)) 464 return -EISDIR; 465 return 0; 466 } 467 468 spin_lock(&sbi->fs_lock); 469 /* 470 * If the dentry has been selected for expire while we slept 471 * on the lock then it might go away. We'll deal with that in 472 * ->d_automount() and wait on a new mount if the expire 473 * succeeds or return here if it doesn't (since there's no 474 * mount to follow with a rootless multi-mount). 475 */ 476 if (!(ino->flags & AUTOFS_INF_EXPIRING)) { 477 /* 478 * Any needed mounting has been completed and the path 479 * updated so check if this is a rootless multi-mount so 480 * we can avoid needless calls ->d_automount() and avoid 481 * an incorrect ELOOP error return. 482 */ 483 if ((!path_is_mountpoint(path) && !autofs_empty(ino)) || 484 (d_really_is_positive(dentry) && d_is_symlink(dentry))) 485 status = -EISDIR; 486 } 487 spin_unlock(&sbi->fs_lock); 488 489 return status; 490} 491 492/* Lookups in the root directory */ 493static struct dentry *autofs_lookup(struct inode *dir, 494 struct dentry *dentry, unsigned int flags) 495{ 496 struct autofs_sb_info *sbi; 497 struct autofs_info *ino; 498 struct dentry *active; 499 500 pr_debug("name = %pd\n", dentry); 501 502 /* File name too long to exist */ 503 if (dentry->d_name.len > NAME_MAX) 504 return ERR_PTR(-ENAMETOOLONG); 505 506 sbi = autofs_sbi(dir->i_sb); 507 508 pr_debug("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n", 509 current->pid, task_pgrp_nr(current), 510 sbi->flags & AUTOFS_SBI_CATATONIC, 511 autofs_oz_mode(sbi)); 512 513 active = autofs_lookup_active(dentry); 514 if (active) 515 return active; 516 else { 517 /* 518 * A dentry that is not within the root can never trigger a 519 * mount operation, unless the directory already exists, so we 520 * can return fail immediately. The daemon however does need 521 * to create directories within the file system. 522 */ 523 if (!autofs_oz_mode(sbi) && !IS_ROOT(dentry->d_parent)) 524 return ERR_PTR(-ENOENT); 525 526 ino = autofs_new_ino(sbi); 527 if (!ino) 528 return ERR_PTR(-ENOMEM); 529 530 spin_lock(&sbi->lookup_lock); 531 spin_lock(&dentry->d_lock); 532 /* Mark entries in the root as mount triggers */ 533 if (IS_ROOT(dentry->d_parent) && 534 autofs_type_indirect(sbi->type)) 535 __managed_dentry_set_managed(dentry); 536 dentry->d_fsdata = ino; 537 ino->dentry = dentry; 538 539 list_add(&ino->active, &sbi->active_list); 540 spin_unlock(&sbi->lookup_lock); 541 spin_unlock(&dentry->d_lock); 542 } 543 return NULL; 544} 545 546static int autofs_dir_permission(struct mnt_idmap *idmap, 547 struct inode *inode, int mask) 548{ 549 if (mask & MAY_WRITE) { 550 struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb); 551 552 if (!autofs_oz_mode(sbi)) 553 return -EACCES; 554 555 /* autofs_oz_mode() needs to allow path walks when the 556 * autofs mount is catatonic but the state of an autofs 557 * file system needs to be preserved over restarts. 558 */ 559 if (sbi->flags & AUTOFS_SBI_CATATONIC) 560 return -EACCES; 561 } 562 563 return generic_permission(idmap, inode, mask); 564} 565 566static int autofs_dir_symlink(struct mnt_idmap *idmap, 567 struct inode *dir, struct dentry *dentry, 568 const char *symname) 569{ 570 struct autofs_info *ino = autofs_dentry_ino(dentry); 571 struct autofs_info *p_ino; 572 struct inode *inode; 573 size_t size = strlen(symname); 574 char *cp; 575 576 pr_debug("%s <- %pd\n", symname, dentry); 577 578 BUG_ON(!ino); 579 580 autofs_clean_ino(ino); 581 582 autofs_del_active(dentry); 583 584 cp = kmalloc(size + 1, GFP_KERNEL); 585 if (!cp) 586 return -ENOMEM; 587 588 strcpy(cp, symname); 589 590 inode = autofs_get_inode(dir->i_sb, S_IFLNK | 0555); 591 if (!inode) { 592 kfree(cp); 593 return -ENOMEM; 594 } 595 inode->i_private = cp; 596 inode->i_size = size; 597 d_add(dentry, inode); 598 599 dget(dentry); 600 p_ino = autofs_dentry_ino(dentry->d_parent); 601 p_ino->count++; 602 603 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); 604 605 return 0; 606} 607 608/* 609 * NOTE! 610 * 611 * Normal filesystems would do a "d_delete()" to tell the VFS dcache 612 * that the file no longer exists. However, doing that means that the 613 * VFS layer can turn the dentry into a negative dentry. We don't want 614 * this, because the unlink is probably the result of an expire. 615 * We simply d_drop it and add it to a expiring list in the super block, 616 * which allows the dentry lookup to check for an incomplete expire. 617 * 618 * If a process is blocked on the dentry waiting for the expire to finish, 619 * it will invalidate the dentry and try to mount with a new one. 620 * 621 * Also see autofs_dir_rmdir().. 622 */ 623static int autofs_dir_unlink(struct inode *dir, struct dentry *dentry) 624{ 625 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); 626 struct autofs_info *ino = autofs_dentry_ino(dentry); 627 struct autofs_info *p_ino; 628 629 p_ino = autofs_dentry_ino(dentry->d_parent); 630 p_ino->count--; 631 dput(ino->dentry); 632 633 d_inode(dentry)->i_size = 0; 634 clear_nlink(d_inode(dentry)); 635 636 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); 637 638 spin_lock(&sbi->lookup_lock); 639 __autofs_add_expiring(dentry); 640 d_drop(dentry); 641 spin_unlock(&sbi->lookup_lock); 642 643 return 0; 644} 645 646/* 647 * Version 4 of autofs provides a pseudo direct mount implementation 648 * that relies on directories at the leaves of a directory tree under 649 * an indirect mount to trigger mounts. To allow for this we need to 650 * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves 651 * of the directory tree. There is no need to clear the automount flag 652 * following a mount or restore it after an expire because these mounts 653 * are always covered. However, it is necessary to ensure that these 654 * flags are clear on non-empty directories to avoid unnecessary calls 655 * during path walks. 656 */ 657static void autofs_set_leaf_automount_flags(struct dentry *dentry) 658{ 659 struct dentry *parent; 660 661 /* root and dentrys in the root are already handled */ 662 if (IS_ROOT(dentry->d_parent)) 663 return; 664 665 managed_dentry_set_managed(dentry); 666 667 parent = dentry->d_parent; 668 /* only consider parents below dentrys in the root */ 669 if (IS_ROOT(parent->d_parent)) 670 return; 671 managed_dentry_clear_managed(parent); 672} 673 674static void autofs_clear_leaf_automount_flags(struct dentry *dentry) 675{ 676 struct dentry *parent; 677 678 /* flags for dentrys in the root are handled elsewhere */ 679 if (IS_ROOT(dentry->d_parent)) 680 return; 681 682 managed_dentry_clear_managed(dentry); 683 684 parent = dentry->d_parent; 685 /* only consider parents below dentrys in the root */ 686 if (IS_ROOT(parent->d_parent)) 687 return; 688 if (autofs_dentry_ino(parent)->count == 2) 689 managed_dentry_set_managed(parent); 690} 691 692static int autofs_dir_rmdir(struct inode *dir, struct dentry *dentry) 693{ 694 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); 695 struct autofs_info *ino = autofs_dentry_ino(dentry); 696 struct autofs_info *p_ino; 697 698 pr_debug("dentry %p, removing %pd\n", dentry, dentry); 699 700 if (ino->count != 1) 701 return -ENOTEMPTY; 702 703 spin_lock(&sbi->lookup_lock); 704 __autofs_add_expiring(dentry); 705 d_drop(dentry); 706 spin_unlock(&sbi->lookup_lock); 707 708 if (sbi->version < 5) 709 autofs_clear_leaf_automount_flags(dentry); 710 711 p_ino = autofs_dentry_ino(dentry->d_parent); 712 p_ino->count--; 713 dput(ino->dentry); 714 d_inode(dentry)->i_size = 0; 715 clear_nlink(d_inode(dentry)); 716 717 if (dir->i_nlink) 718 drop_nlink(dir); 719 720 return 0; 721} 722 723static int autofs_dir_mkdir(struct mnt_idmap *idmap, 724 struct inode *dir, struct dentry *dentry, 725 umode_t mode) 726{ 727 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); 728 struct autofs_info *ino = autofs_dentry_ino(dentry); 729 struct autofs_info *p_ino; 730 struct inode *inode; 731 732 pr_debug("dentry %p, creating %pd\n", dentry, dentry); 733 734 BUG_ON(!ino); 735 736 autofs_clean_ino(ino); 737 738 autofs_del_active(dentry); 739 740 inode = autofs_get_inode(dir->i_sb, S_IFDIR | mode); 741 if (!inode) 742 return -ENOMEM; 743 d_add(dentry, inode); 744 745 if (sbi->version < 5) 746 autofs_set_leaf_automount_flags(dentry); 747 748 dget(dentry); 749 p_ino = autofs_dentry_ino(dentry->d_parent); 750 p_ino->count++; 751 inc_nlink(dir); 752 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); 753 754 return 0; 755} 756 757/* Get/set timeout ioctl() operation */ 758#ifdef CONFIG_COMPAT 759static inline int autofs_compat_get_set_timeout(struct autofs_sb_info *sbi, 760 compat_ulong_t __user *p) 761{ 762 unsigned long ntimeout; 763 int rv; 764 765 rv = get_user(ntimeout, p); 766 if (rv) 767 goto error; 768 769 rv = put_user(sbi->exp_timeout/HZ, p); 770 if (rv) 771 goto error; 772 773 if (ntimeout > UINT_MAX/HZ) 774 sbi->exp_timeout = 0; 775 else 776 sbi->exp_timeout = ntimeout * HZ; 777 778 return 0; 779error: 780 return rv; 781} 782#endif 783 784static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi, 785 unsigned long __user *p) 786{ 787 unsigned long ntimeout; 788 int rv; 789 790 rv = get_user(ntimeout, p); 791 if (rv) 792 goto error; 793 794 rv = put_user(sbi->exp_timeout/HZ, p); 795 if (rv) 796 goto error; 797 798 if (ntimeout > ULONG_MAX/HZ) 799 sbi->exp_timeout = 0; 800 else 801 sbi->exp_timeout = ntimeout * HZ; 802 803 return 0; 804error: 805 return rv; 806} 807 808/* Return protocol version */ 809static inline int autofs_get_protover(struct autofs_sb_info *sbi, 810 int __user *p) 811{ 812 return put_user(sbi->version, p); 813} 814 815/* Return protocol sub version */ 816static inline int autofs_get_protosubver(struct autofs_sb_info *sbi, 817 int __user *p) 818{ 819 return put_user(sbi->sub_version, p); 820} 821 822/* 823* Tells the daemon whether it can umount the autofs mount. 824*/ 825static inline int autofs_ask_umount(struct vfsmount *mnt, int __user *p) 826{ 827 int status = 0; 828 829 if (may_umount(mnt)) 830 status = 1; 831 832 pr_debug("may umount %d\n", status); 833 834 status = put_user(status, p); 835 836 return status; 837} 838 839/* Identify autofs_dentries - this is so we can tell if there's 840 * an extra dentry refcount or not. We only hold a refcount on the 841 * dentry if its non-negative (ie, d_inode != NULL) 842 */ 843int is_autofs_dentry(struct dentry *dentry) 844{ 845 return dentry && d_really_is_positive(dentry) && 846 dentry->d_op == &autofs_dentry_operations && 847 dentry->d_fsdata != NULL; 848} 849 850/* 851 * ioctl()'s on the root directory is the chief method for the daemon to 852 * generate kernel reactions 853 */ 854static int autofs_root_ioctl_unlocked(struct inode *inode, struct file *filp, 855 unsigned int cmd, unsigned long arg) 856{ 857 struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb); 858 void __user *p = (void __user *)arg; 859 860 pr_debug("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n", 861 cmd, arg, sbi, task_pgrp_nr(current)); 862 863 if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || 864 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) 865 return -ENOTTY; 866 867 if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) 868 return -EPERM; 869 870 switch (cmd) { 871 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ 872 return autofs_wait_release(sbi, (autofs_wqt_t) arg, 0); 873 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ 874 return autofs_wait_release(sbi, (autofs_wqt_t) arg, -ENOENT); 875 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ 876 autofs_catatonic_mode(sbi); 877 return 0; 878 case AUTOFS_IOC_PROTOVER: /* Get protocol version */ 879 return autofs_get_protover(sbi, p); 880 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */ 881 return autofs_get_protosubver(sbi, p); 882 case AUTOFS_IOC_SETTIMEOUT: 883 return autofs_get_set_timeout(sbi, p); 884#ifdef CONFIG_COMPAT 885 case AUTOFS_IOC_SETTIMEOUT32: 886 return autofs_compat_get_set_timeout(sbi, p); 887#endif 888 889 case AUTOFS_IOC_ASKUMOUNT: 890 return autofs_ask_umount(filp->f_path.mnt, p); 891 892 /* return a single thing to expire */ 893 case AUTOFS_IOC_EXPIRE: 894 return autofs_expire_run(inode->i_sb, filp->f_path.mnt, sbi, p); 895 /* same as above, but can send multiple expires through pipe */ 896 case AUTOFS_IOC_EXPIRE_MULTI: 897 return autofs_expire_multi(inode->i_sb, 898 filp->f_path.mnt, sbi, p); 899 900 default: 901 return -EINVAL; 902 } 903} 904 905static long autofs_root_ioctl(struct file *filp, 906 unsigned int cmd, unsigned long arg) 907{ 908 struct inode *inode = file_inode(filp); 909 910 return autofs_root_ioctl_unlocked(inode, filp, cmd, arg); 911} 912 913#ifdef CONFIG_COMPAT 914static long autofs_root_compat_ioctl(struct file *filp, 915 unsigned int cmd, unsigned long arg) 916{ 917 struct inode *inode = file_inode(filp); 918 int ret; 919 920 if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL) 921 ret = autofs_root_ioctl_unlocked(inode, filp, cmd, arg); 922 else 923 ret = autofs_root_ioctl_unlocked(inode, filp, cmd, 924 (unsigned long) compat_ptr(arg)); 925 926 return ret; 927} 928#endif 929