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[PATCH] capable/capability.h (fs/)
[linux-2.6-block.git] / fs / autofs4 / root.c
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1da177e4
LT		 1/* -*- c -*- --------------------------------------------------------------- *
2 *
3 * linux/fs/autofs/root.c
4 *
5 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6 * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
7 * Copyright 2001-2003 Ian Kent <raven@themaw.net>
8 *
9 * This file is part of the Linux kernel and is made available under
10 * the terms of the GNU General Public License, version 2, or at your
11 * option, any later version, incorporated herein by reference.
12 *
13 * ------------------------------------------------------------------------- */
14
16f7e0fe 15#include <linux/capability.h>
1da177e4
LT		 16#include <linux/errno.h>
17#include <linux/stat.h>
18#include <linux/param.h>
19#include <linux/time.h>
20#include <linux/smp_lock.h>
21#include "autofs_i.h"
22
23static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
24static int autofs4_dir_unlink(struct inode *,struct dentry *);
25static int autofs4_dir_rmdir(struct inode *,struct dentry *);
26static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
27static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
28static int autofs4_dir_open(struct inode *inode, struct file *file);
29static int autofs4_dir_close(struct inode *inode, struct file *file);
30static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
31static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
32static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
33static int autofs4_dcache_readdir(struct file *, void *, filldir_t);
34
35struct file_operations autofs4_root_operations = {
36 .open = dcache_dir_open,
37 .release = dcache_dir_close,
38 .read = generic_read_dir,
39 .readdir = autofs4_root_readdir,
40 .ioctl = autofs4_root_ioctl,
41};
42
43struct file_operations autofs4_dir_operations = {
44 .open = autofs4_dir_open,
45 .release = autofs4_dir_close,
46 .read = generic_read_dir,
47 .readdir = autofs4_dir_readdir,
48};
49
50struct inode_operations autofs4_root_inode_operations = {
51 .lookup = autofs4_lookup,
52 .unlink = autofs4_dir_unlink,
53 .symlink = autofs4_dir_symlink,
54 .mkdir = autofs4_dir_mkdir,
55 .rmdir = autofs4_dir_rmdir,
56};
57
58struct inode_operations autofs4_dir_inode_operations = {
59 .lookup = autofs4_lookup,
60 .unlink = autofs4_dir_unlink,
61 .symlink = autofs4_dir_symlink,
62 .mkdir = autofs4_dir_mkdir,
63 .rmdir = autofs4_dir_rmdir,
64};
65
66static int autofs4_root_readdir(struct file *file, void *dirent,
67 filldir_t filldir)
68{
69 struct autofs_sb_info *sbi = autofs4_sbi(file->f_dentry->d_sb);
70 int oz_mode = autofs4_oz_mode(sbi);
71
72 DPRINTK("called, filp->f_pos = %lld", file->f_pos);
73
74 /*
75 * Don't set reghost flag if:
76 * 1) f_pos is larger than zero -- we've already been here.
77 * 2) we haven't even enabled reghosting in the 1st place.
78 * 3) this is the daemon doing a readdir
79 */
80 if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled)
81 sbi->needs_reghost = 1;
82
83 DPRINTK("needs_reghost = %d", sbi->needs_reghost);
84
85 return autofs4_dcache_readdir(file, dirent, filldir);
86}
87
88/* Update usage from here to top of tree, so that scan of
89 top-level directories will give a useful result */
9cf6f4b3 90static void autofs4_update_usage(struct vfsmount *mnt, struct dentry *dentry)
1da177e4
LT		 91{
92 struct dentry *top = dentry->d_sb->s_root;
93
94 spin_lock(&dcache_lock);
95 for(; dentry != top; dentry = dentry->d_parent) {
96 struct autofs_info *ino = autofs4_dentry_ino(dentry);
97
98 if (ino) {
9cf6f4b3 99 touch_atime(mnt, dentry);
1da177e4
LT		 100 ino->last_used = jiffies;
101 }
102 }
103 spin_unlock(&dcache_lock);
104}
105
106/*
107 * From 2.4 kernel readdir.c
108 */
109static int autofs4_dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
110{
111 int i;
112 struct dentry *dentry = filp->f_dentry;
113
114 i = filp->f_pos;
115 switch (i) {
116 case 0:
117 if (filldir(dirent, ".", 1, i, dentry->d_inode->i_ino, DT_DIR) < 0)
118 break;
119 i++;
120 filp->f_pos++;
121 /* fallthrough */
122 case 1:
123 if (filldir(dirent, "..", 2, i, dentry->d_parent->d_inode->i_ino, DT_DIR) < 0)
124 break;
125 i++;
126 filp->f_pos++;
127 /* fallthrough */
128 default: {
129 struct list_head *list;
130 int j = i-2;
131
132 spin_lock(&dcache_lock);
133 list = dentry->d_subdirs.next;
134
135 for (;;) {
136 if (list == &dentry->d_subdirs) {
137 spin_unlock(&dcache_lock);
138 return 0;
139 }
140 if (!j)
141 break;
142 j--;
143 list = list->next;
144 }
145
146 while(1) {
5160ee6f
ED		 147 struct dentry *de = list_entry(list,
148 struct dentry, d_u.d_child);
1da177e4
LT		 149
150 if (!d_unhashed(de) && de->d_inode) {
151 spin_unlock(&dcache_lock);
152 if (filldir(dirent, de->d_name.name, de->d_name.len, filp->f_pos, de->d_inode->i_ino, DT_UNKNOWN) < 0)
153 break;
154 spin_lock(&dcache_lock);
155 }
156 filp->f_pos++;
157 list = list->next;
158 if (list != &dentry->d_subdirs)
159 continue;
160 spin_unlock(&dcache_lock);
161 break;
162 }
163 }
164 }
165 return 0;
166}
167
168static int autofs4_dir_open(struct inode *inode, struct file *file)
169{
170 struct dentry *dentry = file->f_dentry;
171 struct vfsmount *mnt = file->f_vfsmnt;
172 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
173 int status;
174
175 DPRINTK("file=%p dentry=%p %.*s",
176 file, dentry, dentry->d_name.len, dentry->d_name.name);
177
178 if (autofs4_oz_mode(sbi))
179 goto out;
180
181 if (autofs4_ispending(dentry)) {
182 DPRINTK("dentry busy");
183 return -EBUSY;
184 }
185
186 if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
187 struct nameidata nd;
188 int empty;
189
190 /* In case there are stale directory dentrys from a failed mount */
191 spin_lock(&dcache_lock);
192 empty = list_empty(&dentry->d_subdirs);
193 spin_unlock(&dcache_lock);
194
195 if (!empty)
196 d_invalidate(dentry);
197
198 nd.flags = LOOKUP_DIRECTORY;
199 status = (dentry->d_op->d_revalidate)(dentry, &nd);
200
201 if (!status)
202 return -ENOENT;
203 }
204
205 if (d_mountpoint(dentry)) {
206 struct file *fp = NULL;
207 struct vfsmount *fp_mnt = mntget(mnt);
208 struct dentry *fp_dentry = dget(dentry);
209
9b1e3afd
IK		 210 if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) {
211 dput(fp_dentry);
212 mntput(fp_mnt);
213 return -ENOENT;
214 }
1da177e4
LT		 215
216 fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
217 status = PTR_ERR(fp);
218 if (IS_ERR(fp)) {
219 file->private_data = NULL;
220 return status;
221 }
222 file->private_data = fp;
223 }
224out:
225 return 0;
226}
227
228static int autofs4_dir_close(struct inode *inode, struct file *file)
229{
230 struct dentry *dentry = file->f_dentry;
231 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
232
233 DPRINTK("file=%p dentry=%p %.*s",
234 file, dentry, dentry->d_name.len, dentry->d_name.name);
235
236 if (autofs4_oz_mode(sbi))
237 goto out;
238
239 if (autofs4_ispending(dentry)) {
240 DPRINTK("dentry busy");
241 return -EBUSY;
242 }
243
244 if (d_mountpoint(dentry)) {
245 struct file *fp = file->private_data;
246
247 if (!fp)
248 return -ENOENT;
249
250 filp_close(fp, current->files);
251 file->private_data = NULL;
252 }
253out:
254 return 0;
255}
256
257static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir)
258{
259 struct dentry *dentry = file->f_dentry;
260 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
261 int status;
262
263 DPRINTK("file=%p dentry=%p %.*s",
264 file, dentry, dentry->d_name.len, dentry->d_name.name);
265
266 if (autofs4_oz_mode(sbi))
267 goto out;
268
269 if (autofs4_ispending(dentry)) {
270 DPRINTK("dentry busy");
271 return -EBUSY;
272 }
273
274 if (d_mountpoint(dentry)) {
275 struct file *fp = file->private_data;
276
277 if (!fp)
278 return -ENOENT;
279
280 if (!fp->f_op || !fp->f_op->readdir)
281 goto out;
282
283 status = vfs_readdir(fp, filldir, dirent);
284 file->f_pos = fp->f_pos;
285 if (status)
286 autofs4_copy_atime(file, fp);
287 return status;
288 }
289out:
290 return autofs4_dcache_readdir(file, dirent, filldir);
291}
292
9cf6f4b3 293static int try_to_fill_dentry(struct vfsmount *mnt, struct dentry *dentry, int flags)
1da177e4 294{
9cf6f4b3
CH		 295 struct super_block *sb = mnt->mnt_sb;
296 struct autofs_sb_info *sbi = autofs4_sbi(sb);
1da177e4
LT		 297 struct autofs_info *de_info = autofs4_dentry_ino(dentry);
298 int status = 0;
299
300 /* Block on any pending expiry here; invalidate the dentry
301 when expiration is done to trigger mount request with a new
302 dentry */
303 if (de_info && (de_info->flags & AUTOFS_INF_EXPIRING)) {
304 DPRINTK("waiting for expire %p name=%.*s",
305 dentry, dentry->d_name.len, dentry->d_name.name);
306
307 status = autofs4_wait(sbi, dentry, NFY_NONE);
308
309 DPRINTK("expire done status=%d", status);
310
1684b2bb
IK		 311 /*
312 * If the directory still exists the mount request must
313 * continue otherwise it can't be followed at the right
314 * time during the walk.
315 */
316 status = d_invalidate(dentry);
317 if (status != -EBUSY)
318 return 0;
1da177e4
LT		 319 }
320
321 DPRINTK("dentry=%p %.*s ino=%p",
322 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
323
324 /* Wait for a pending mount, triggering one if there isn't one already */
325 if (dentry->d_inode == NULL) {
326 DPRINTK("waiting for mount name=%.*s",
327 dentry->d_name.len, dentry->d_name.name);
328
329 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
330
331 DPRINTK("mount done status=%d", status);
332
333 if (status && dentry->d_inode)
334 return 0; /* Try to get the kernel to invalidate this dentry */
335
336 /* Turn this into a real negative dentry? */
337 if (status == -ENOENT) {
338 dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
339 spin_lock(&dentry->d_lock);
340 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
341 spin_unlock(&dentry->d_lock);
342 return 1;
343 } else if (status) {
344 /* Return a negative dentry, but leave it "pending" */
345 return 1;
346 }
347 /* Trigger mount for path component or follow link */
348 } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
349 current->link_count) {
350 DPRINTK("waiting for mount name=%.*s",
351 dentry->d_name.len, dentry->d_name.name);
352
353 spin_lock(&dentry->d_lock);
354 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
355 spin_unlock(&dentry->d_lock);
356 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
357
358 DPRINTK("mount done status=%d", status);
359
360 if (status) {
361 spin_lock(&dentry->d_lock);
362 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
363 spin_unlock(&dentry->d_lock);
364 return 0;
365 }
366 }
367
368 /* We don't update the usages for the autofs daemon itself, this
369 is necessary for recursive autofs mounts */
370 if (!autofs4_oz_mode(sbi))
9cf6f4b3 371 autofs4_update_usage(mnt, dentry);
1da177e4
LT		 372
373 spin_lock(&dentry->d_lock);
374 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
375 spin_unlock(&dentry->d_lock);
376 return 1;
377}
378
379/*
380 * Revalidate is called on every cache lookup. Some of those
381 * cache lookups may actually happen while the dentry is not
382 * yet completely filled in, and revalidate has to delay such
383 * lookups..
384 */
385static int autofs4_revalidate(struct dentry * dentry, struct nameidata *nd)
386{
387 struct inode * dir = dentry->d_parent->d_inode;
388 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
389 int oz_mode = autofs4_oz_mode(sbi);
390 int flags = nd ? nd->flags : 0;
391 int status = 1;
392
393 /* Pending dentry */
394 if (autofs4_ispending(dentry)) {
395 if (!oz_mode)
9cf6f4b3 396 status = try_to_fill_dentry(nd->mnt, dentry, flags);
1da177e4
LT		 397 return status;
398 }
399
400 /* Negative dentry.. invalidate if "old" */
401 if (dentry->d_inode == NULL)
402 return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
403
404 /* Check for a non-mountpoint directory with no contents */
405 spin_lock(&dcache_lock);
406 if (S_ISDIR(dentry->d_inode->i_mode) &&
407 !d_mountpoint(dentry) &&
408 list_empty(&dentry->d_subdirs)) {
409 DPRINTK("dentry=%p %.*s, emptydir",
410 dentry, dentry->d_name.len, dentry->d_name.name);
411 spin_unlock(&dcache_lock);
412 if (!oz_mode)
9cf6f4b3 413 status = try_to_fill_dentry(nd->mnt, dentry, flags);
1da177e4
LT		 414 return status;
415 }
416 spin_unlock(&dcache_lock);
417
418 /* Update the usage list */
419 if (!oz_mode)
9cf6f4b3 420 autofs4_update_usage(nd->mnt, dentry);
1da177e4
LT		 421
422 return 1;
423}
424
425static void autofs4_dentry_release(struct dentry *de)
426{
427 struct autofs_info *inf;
428
429 DPRINTK("releasing %p", de);
430
431 inf = autofs4_dentry_ino(de);
432 de->d_fsdata = NULL;
433
434 if (inf) {
435 inf->dentry = NULL;
436 inf->inode = NULL;
437
438 autofs4_free_ino(inf);
439 }
440}
441
442/* For dentries of directories in the root dir */
443static struct dentry_operations autofs4_root_dentry_operations = {
444 .d_revalidate = autofs4_revalidate,
445 .d_release = autofs4_dentry_release,
446};
447
448/* For other dentries */
449static struct dentry_operations autofs4_dentry_operations = {
450 .d_revalidate = autofs4_revalidate,
451 .d_release = autofs4_dentry_release,
452};
453
454/* Lookups in the root directory */
455static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
456{
457 struct autofs_sb_info *sbi;
458 int oz_mode;
459
460 DPRINTK("name = %.*s",
461 dentry->d_name.len, dentry->d_name.name);
462
463 if (dentry->d_name.len > NAME_MAX)
464 return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
465
466 sbi = autofs4_sbi(dir->i_sb);
467
468 oz_mode = autofs4_oz_mode(sbi);
469 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
470 current->pid, process_group(current), sbi->catatonic, oz_mode);
471
472 /*
473 * Mark the dentry incomplete, but add it. This is needed so
474 * that the VFS layer knows about the dentry, and we can count
475 * on catching any lookups through the revalidate.
476 *
477 * Let all the hard work be done by the revalidate function that
478 * needs to be able to do this anyway..
479 *
480 * We need to do this before we release the directory semaphore.
481 */
482 dentry->d_op = &autofs4_root_dentry_operations;
483
484 if (!oz_mode) {
485 spin_lock(&dentry->d_lock);
486 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
487 spin_unlock(&dentry->d_lock);
488 }
489 dentry->d_fsdata = NULL;
490 d_add(dentry, NULL);
491
492 if (dentry->d_op && dentry->d_op->d_revalidate) {
1b1dcc1b 493 mutex_unlock(&dir->i_mutex);
1da177e4 494 (dentry->d_op->d_revalidate)(dentry, nd);
1b1dcc1b 495 mutex_lock(&dir->i_mutex);
1da177e4
LT		 496 }
497
498 /*
499 * If we are still pending, check if we had to handle
500 * a signal. If so we can force a restart..
501 */
502 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
503 /* See if we were interrupted */
504 if (signal_pending(current)) {
505 sigset_t *sigset = &current->pending.signal;
506 if (sigismember (sigset, SIGKILL) ||
507 sigismember (sigset, SIGQUIT) ||
508 sigismember (sigset, SIGINT)) {
509 return ERR_PTR(-ERESTARTNOINTR);
510 }
511 }
512 }
513
514 /*
515 * If this dentry is unhashed, then we shouldn't honour this
516 * lookup even if the dentry is positive. Returning ENOENT here
517 * doesn't do the right thing for all system calls, but it should
518 * be OK for the operations we permit from an autofs.
519 */
520 if ( dentry->d_inode && d_unhashed(dentry) )
521 return ERR_PTR(-ENOENT);
522
523 return NULL;
524}
525
526static int autofs4_dir_symlink(struct inode *dir,
527 struct dentry *dentry,
528 const char *symname)
529{
530 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
531 struct autofs_info *ino = autofs4_dentry_ino(dentry);
532 struct inode *inode;
533 char *cp;
534
535 DPRINTK("%s <- %.*s", symname,
536 dentry->d_name.len, dentry->d_name.name);
537
538 if (!autofs4_oz_mode(sbi))
539 return -EACCES;
540
541 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
542 if (ino == NULL)
543 return -ENOSPC;
544
545 ino->size = strlen(symname);
546 ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
547
548 if (cp == NULL) {
549 kfree(ino);
550 return -ENOSPC;
551 }
552
553 strcpy(cp, symname);
554
555 inode = autofs4_get_inode(dir->i_sb, ino);
556 d_instantiate(dentry, inode);
557
558 if (dir == dir->i_sb->s_root->d_inode)
559 dentry->d_op = &autofs4_root_dentry_operations;
560 else
561 dentry->d_op = &autofs4_dentry_operations;
562
563 dentry->d_fsdata = ino;
564 ino->dentry = dget(dentry);
565 ino->inode = inode;
566
567 dir->i_mtime = CURRENT_TIME;
568
569 return 0;
570}
571
572/*
573 * NOTE!
574 *
575 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
576 * that the file no longer exists. However, doing that means that the
577 * VFS layer can turn the dentry into a negative dentry. We don't want
578 * this, because since the unlink is probably the result of an expire.
579 * We simply d_drop it, which allows the dentry lookup to remount it
580 * if necessary.
581 *
582 * If a process is blocked on the dentry waiting for the expire to finish,
583 * it will invalidate the dentry and try to mount with a new one.
584 *
585 * Also see autofs4_dir_rmdir()..
586 */
587static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
588{
589 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
590 struct autofs_info *ino = autofs4_dentry_ino(dentry);
591
592 /* This allows root to remove symlinks */
593 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
594 return -EACCES;
595
596 dput(ino->dentry);
597
598 dentry->d_inode->i_size = 0;
599 dentry->d_inode->i_nlink = 0;
600
601 dir->i_mtime = CURRENT_TIME;
602
603 d_drop(dentry);
604
605 return 0;
606}
607
608static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
609{
610 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
611 struct autofs_info *ino = autofs4_dentry_ino(dentry);
612
613 if (!autofs4_oz_mode(sbi))
614 return -EACCES;
615
616 spin_lock(&dcache_lock);
617 if (!list_empty(&dentry->d_subdirs)) {
618 spin_unlock(&dcache_lock);
619 return -ENOTEMPTY;
620 }
621 spin_lock(&dentry->d_lock);
622 __d_drop(dentry);
623 spin_unlock(&dentry->d_lock);
624 spin_unlock(&dcache_lock);
625
626 dput(ino->dentry);
627
628 dentry->d_inode->i_size = 0;
629 dentry->d_inode->i_nlink = 0;
630
631 if (dir->i_nlink)
632 dir->i_nlink--;
633
634 return 0;
635}
636
637static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
638{
639 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
640 struct autofs_info *ino = autofs4_dentry_ino(dentry);
641 struct inode *inode;
642
643 if ( !autofs4_oz_mode(sbi) )
644 return -EACCES;
645
646 DPRINTK("dentry %p, creating %.*s",
647 dentry, dentry->d_name.len, dentry->d_name.name);
648
649 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
650 if (ino == NULL)
651 return -ENOSPC;
652
653 inode = autofs4_get_inode(dir->i_sb, ino);
654 d_instantiate(dentry, inode);
655
656 if (dir == dir->i_sb->s_root->d_inode)
657 dentry->d_op = &autofs4_root_dentry_operations;
658 else
659 dentry->d_op = &autofs4_dentry_operations;
660
661 dentry->d_fsdata = ino;
662 ino->dentry = dget(dentry);
663 ino->inode = inode;
664 dir->i_nlink++;
665 dir->i_mtime = CURRENT_TIME;
666
667 return 0;
668}
669
670/* Get/set timeout ioctl() operation */
671static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
672 unsigned long __user *p)
673{
674 int rv;
675 unsigned long ntimeout;
676
677 if ( (rv = get_user(ntimeout, p)) ||
678 (rv = put_user(sbi->exp_timeout/HZ, p)) )
679 return rv;
680
681 if ( ntimeout > ULONG_MAX/HZ )
682 sbi->exp_timeout = 0;
683 else
684 sbi->exp_timeout = ntimeout * HZ;
685
686 return 0;
687}
688
689/* Return protocol version */
690static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
691{
692 return put_user(sbi->version, p);
693}
694
695/* Return protocol sub version */
696static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
697{
698 return put_user(sbi->sub_version, p);
699}
700
701/*
702 * Tells the daemon whether we need to reghost or not. Also, clears
703 * the reghost_needed flag.
704 */
705static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
706{
707 int status;
708
709 DPRINTK("returning %d", sbi->needs_reghost);
710
711 status = put_user(sbi->needs_reghost, p);
712 if ( status )
713 return status;
714
715 sbi->needs_reghost = 0;
716 return 0;
717}
718
719/*
720 * Enable / Disable reghosting ioctl() operation
721 */
722static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
723{
724 int status;
725 int val;
726
727 status = get_user(val, p);
728
729 DPRINTK("reghost = %d", val);
730
731 if (status)
732 return status;
733
734 /* turn on/off reghosting, with the val */
735 sbi->reghost_enabled = val;
736 return 0;
737}
738
739/*
740* Tells the daemon whether it can umount the autofs mount.
741*/
742static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
743{
744 int status = 0;
745
746 if (may_umount(mnt) == 0)
747 status = 1;
748
749 DPRINTK("returning %d", status);
750
751 status = put_user(status, p);
752
753 return status;
754}
755
756/* Identify autofs4_dentries - this is so we can tell if there's
757 an extra dentry refcount or not. We only hold a refcount on the
758 dentry if its non-negative (ie, d_inode != NULL)
759*/
760int is_autofs4_dentry(struct dentry *dentry)
761{
762 return dentry && dentry->d_inode &&
763 (dentry->d_op == &autofs4_root_dentry_operations ||
764 dentry->d_op == &autofs4_dentry_operations) &&
765 dentry->d_fsdata != NULL;
766}
767
768/*
769 * ioctl()'s on the root directory is the chief method for the daemon to
770 * generate kernel reactions
771 */
772static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
773 unsigned int cmd, unsigned long arg)
774{
775 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
776 void __user *p = (void __user *)arg;
777
778 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
779 cmd,arg,sbi,process_group(current));
780
781 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
782 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
783 return -ENOTTY;
784
785 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
786 return -EPERM;
787
788 switch(cmd) {
789 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
790 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
791 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
792 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
793 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
794 autofs4_catatonic_mode(sbi);
795 return 0;
796 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
797 return autofs4_get_protover(sbi, p);
798 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
799 return autofs4_get_protosubver(sbi, p);
800 case AUTOFS_IOC_SETTIMEOUT:
801 return autofs4_get_set_timeout(sbi, p);
802
803 case AUTOFS_IOC_TOGGLEREGHOST:
804 return autofs4_toggle_reghost(sbi, p);
805 case AUTOFS_IOC_ASKREGHOST:
806 return autofs4_ask_reghost(sbi, p);
807
808 case AUTOFS_IOC_ASKUMOUNT:
809 return autofs4_ask_umount(filp->f_vfsmnt, p);
810
811 /* return a single thing to expire */
812 case AUTOFS_IOC_EXPIRE:
813 return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, p);
814 /* same as above, but can send multiple expires through pipe */
815 case AUTOFS_IOC_EXPIRE_MULTI:
816 return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, p);
817
818 default:
819 return -ENOSYS;
820 }
821}
Linux 6.x block layer and io_uring tree(s)