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