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
13 static int autofs_dir_permission(struct mnt_idmap *, struct inode *, int);
14 static int autofs_dir_symlink(struct mnt_idmap *, struct inode *,
15 struct dentry *, const char *);
16 static int autofs_dir_unlink(struct inode *, struct dentry *);
17 static int autofs_dir_rmdir(struct inode *, struct dentry *);
18 static int autofs_dir_mkdir(struct mnt_idmap *, struct inode *,
19 struct dentry *, umode_t);
20 static long autofs_root_ioctl(struct file *, unsigned int, unsigned long);
21 #ifdef CONFIG_COMPAT
22 static long autofs_root_compat_ioctl(struct file *,
23 unsigned int, unsigned long);
24 #endif
25 static int autofs_dir_open(struct inode *inode, struct file *file);
26 static struct dentry *autofs_lookup(struct inode *,
27 struct dentry *, unsigned int);
28 static struct vfsmount *autofs_d_automount(struct path *);
29 static int autofs_d_manage(const struct path *, bool);
30 static void autofs_dentry_release(struct dentry *);
31
32 const 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
44 const 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
52 const 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
61 const 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
autofs_del_active(struct dentry * dentry)67 static 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
autofs_dir_open(struct inode * inode,struct file * file)78 static 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
105 out:
106 return dcache_dir_open(inode, file);
107 }
108
autofs_dentry_release(struct dentry * de)109 static 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
autofs_lookup_active(struct dentry * dentry)131 static 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 }
177 next:
178 spin_unlock(&active->d_lock);
179 }
180 spin_unlock(&sbi->lookup_lock);
181
182 return NULL;
183 }
184
autofs_lookup_expiring(struct dentry * dentry,bool rcu_walk)185 static 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 }
237 next:
238 spin_unlock(&expiring->d_lock);
239 }
240 spin_unlock(&sbi->lookup_lock);
241
242 return NULL;
243 }
244
autofs_mount_wait(const struct path * path,bool rcu_walk)245 static 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
do_expire_wait(const struct path * path,bool rcu_walk)265 static 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
autofs_mountpoint_changed(struct path * path)289 static 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
autofs_d_automount(struct path * path)331 static 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);
410 done:
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
autofs_d_manage(const struct path * path,bool rcu_walk)419 static 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 */
autofs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)493 static 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
autofs_dir_permission(struct mnt_idmap * idmap,struct inode * inode,int mask)546 static 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
autofs_dir_symlink(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,const char * symname)566 static 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 dir->i_mtime = 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 */
autofs_dir_unlink(struct inode * dir,struct dentry * dentry)623 static 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 dir->i_mtime = 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 */
autofs_set_leaf_automount_flags(struct dentry * dentry)657 static 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
autofs_clear_leaf_automount_flags(struct dentry * dentry)674 static 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
autofs_dir_rmdir(struct inode * dir,struct dentry * dentry)692 static 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
autofs_dir_mkdir(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode)723 static 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 dir->i_mtime = inode_set_ctime_current(dir);
753
754 return 0;
755 }
756
757 /* Get/set timeout ioctl() operation */
758 #ifdef CONFIG_COMPAT
autofs_compat_get_set_timeout(struct autofs_sb_info * sbi,compat_ulong_t __user * p)759 static 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;
779 error:
780 return rv;
781 }
782 #endif
783
autofs_get_set_timeout(struct autofs_sb_info * sbi,unsigned long __user * p)784 static 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;
804 error:
805 return rv;
806 }
807
808 /* Return protocol version */
autofs_get_protover(struct autofs_sb_info * sbi,int __user * p)809 static 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 */
autofs_get_protosubver(struct autofs_sb_info * sbi,int __user * p)816 static 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 */
autofs_ask_umount(struct vfsmount * mnt,int __user * p)825 static 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 */
is_autofs_dentry(struct dentry * dentry)843 int 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 */
autofs_root_ioctl_unlocked(struct inode * inode,struct file * filp,unsigned int cmd,unsigned long arg)854 static 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
autofs_root_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)905 static 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
autofs_root_compat_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)914 static 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