blob: e698c51d2b02f167b151dfb04e515870b8dd2c31 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* -*- linux-c -*- --------------------------------------------------------- *
2 *
3 * linux/fs/autofs/root.c
4 *
5 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6 *
7 * This file is part of the Linux kernel and is made available under
8 * the terms of the GNU General Public License, version 2, or at your
9 * option, any later version, incorporated herein by reference.
10 *
11 * ------------------------------------------------------------------------- */
12
Randy Dunlap16f7e0f2006-01-11 12:17:46 -080013#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/errno.h>
15#include <linux/stat.h>
16#include <linux/param.h>
17#include <linux/time.h>
18#include <linux/smp_lock.h>
19#include "autofs_i.h"
20
21static int autofs_root_readdir(struct file *,void *,filldir_t);
22static struct dentry *autofs_root_lookup(struct inode *,struct dentry *, struct nameidata *);
23static int autofs_root_symlink(struct inode *,struct dentry *,const char *);
24static int autofs_root_unlink(struct inode *,struct dentry *);
25static int autofs_root_rmdir(struct inode *,struct dentry *);
26static int autofs_root_mkdir(struct inode *,struct dentry *,int);
27static int autofs_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
28
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080029const struct file_operations autofs_root_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 .read = generic_read_dir,
31 .readdir = autofs_root_readdir,
32 .ioctl = autofs_root_ioctl,
33};
34
35struct inode_operations autofs_root_inode_operations = {
36 .lookup = autofs_root_lookup,
37 .unlink = autofs_root_unlink,
38 .symlink = autofs_root_symlink,
39 .mkdir = autofs_root_mkdir,
40 .rmdir = autofs_root_rmdir,
41};
42
43static int autofs_root_readdir(struct file *filp, void *dirent, filldir_t filldir)
44{
45 struct autofs_dir_ent *ent = NULL;
46 struct autofs_dirhash *dirhash;
47 struct autofs_sb_info *sbi;
Josef "Jeff" Sipek81ed19b2006-12-08 02:36:46 -080048 struct inode * inode = filp->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 off_t onr, nr;
50
51 lock_kernel();
52
53 sbi = autofs_sbi(inode->i_sb);
54 dirhash = &sbi->dirhash;
55 nr = filp->f_pos;
56
57 switch(nr)
58 {
59 case 0:
60 if (filldir(dirent, ".", 1, nr, inode->i_ino, DT_DIR) < 0)
61 goto out;
62 filp->f_pos = ++nr;
63 /* fall through */
64 case 1:
65 if (filldir(dirent, "..", 2, nr, inode->i_ino, DT_DIR) < 0)
66 goto out;
67 filp->f_pos = ++nr;
68 /* fall through */
69 default:
70 while ( onr = nr, ent = autofs_hash_enum(dirhash,&nr,ent) ) {
71 if ( !ent->dentry || d_mountpoint(ent->dentry) ) {
72 if (filldir(dirent,ent->name,ent->len,onr,ent->ino,DT_UNKNOWN) < 0)
73 goto out;
74 filp->f_pos = nr;
75 }
76 }
77 break;
78 }
79
80out:
81 unlock_kernel();
82 return 0;
83}
84
85static int try_to_fill_dentry(struct dentry *dentry, struct super_block *sb, struct autofs_sb_info *sbi)
86{
87 struct inode * inode;
88 struct autofs_dir_ent *ent;
89 int status = 0;
90
91 if ( !(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)) ) {
92 do {
93 if ( status && dentry->d_inode ) {
94 if ( status != -ENOENT )
95 printk("autofs warning: lookup failure on positive dentry, status = %d, name = %s\n", status, dentry->d_name.name);
96 return 0; /* Try to get the kernel to invalidate this dentry */
97 }
98
99 /* Turn this into a real negative dentry? */
100 if (status == -ENOENT) {
101 dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
102 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
103 return 1;
104 } else if (status) {
105 /* Return a negative dentry, but leave it "pending" */
106 return 1;
107 }
108 status = autofs_wait(sbi, &dentry->d_name);
109 } while (!(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)) );
110 }
111
112 /* Abuse this field as a pointer to the directory entry, used to
113 find the expire list pointers */
114 dentry->d_time = (unsigned long) ent;
115
116 if (!dentry->d_inode) {
117 inode = iget(sb, ent->ino);
118 if (!inode) {
119 /* Failed, but leave pending for next time */
120 return 1;
121 }
122 dentry->d_inode = inode;
123 }
124
125 /* If this is a directory that isn't a mount point, bitch at the
126 daemon and fix it in user space */
127 if ( S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) ) {
128 return !autofs_wait(sbi, &dentry->d_name);
129 }
130
131 /* We don't update the usages for the autofs daemon itself, this
132 is necessary for recursive autofs mounts */
133 if ( !autofs_oz_mode(sbi) ) {
134 autofs_update_usage(&sbi->dirhash,ent);
135 }
136
137 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
138 return 1;
139}
140
141
142/*
143 * Revalidate is called on every cache lookup. Some of those
144 * cache lookups may actually happen while the dentry is not
145 * yet completely filled in, and revalidate has to delay such
146 * lookups..
147 */
148static int autofs_revalidate(struct dentry * dentry, struct nameidata *nd)
149{
150 struct inode * dir;
151 struct autofs_sb_info *sbi;
152 struct autofs_dir_ent *ent;
153 int res;
154
155 lock_kernel();
156 dir = dentry->d_parent->d_inode;
157 sbi = autofs_sbi(dir->i_sb);
158
159 /* Pending dentry */
160 if ( dentry->d_flags & DCACHE_AUTOFS_PENDING ) {
161 if (autofs_oz_mode(sbi))
162 res = 1;
163 else
164 res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
165 unlock_kernel();
166 return res;
167 }
168
169 /* Negative dentry.. invalidate if "old" */
170 if (!dentry->d_inode) {
171 unlock_kernel();
172 return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
173 }
174
175 /* Check for a non-mountpoint directory */
176 if ( S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) ) {
177 if (autofs_oz_mode(sbi))
178 res = 1;
179 else
180 res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
181 unlock_kernel();
182 return res;
183 }
184
185 /* Update the usage list */
186 if ( !autofs_oz_mode(sbi) ) {
187 ent = (struct autofs_dir_ent *) dentry->d_time;
188 if ( ent )
189 autofs_update_usage(&sbi->dirhash,ent);
190 }
191 unlock_kernel();
192 return 1;
193}
194
195static struct dentry_operations autofs_dentry_operations = {
196 .d_revalidate = autofs_revalidate,
197};
198
199static struct dentry *autofs_root_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
200{
201 struct autofs_sb_info *sbi;
202 int oz_mode;
203
204 DPRINTK(("autofs_root_lookup: name = "));
205 lock_kernel();
206 autofs_say(dentry->d_name.name,dentry->d_name.len);
207
208 if (dentry->d_name.len > NAME_MAX) {
209 unlock_kernel();
210 return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
211 }
212
213 sbi = autofs_sbi(dir->i_sb);
214
215 oz_mode = autofs_oz_mode(sbi);
216 DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
217 current->pid, process_group(current), sbi->catatonic, oz_mode));
218
219 /*
220 * Mark the dentry incomplete, but add it. This is needed so
221 * that the VFS layer knows about the dentry, and we can count
222 * on catching any lookups through the revalidate.
223 *
224 * Let all the hard work be done by the revalidate function that
225 * needs to be able to do this anyway..
226 *
227 * We need to do this before we release the directory semaphore.
228 */
229 dentry->d_op = &autofs_dentry_operations;
230 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
231 d_add(dentry, NULL);
232
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800233 mutex_unlock(&dir->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 autofs_revalidate(dentry, nd);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800235 mutex_lock(&dir->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
237 /*
238 * If we are still pending, check if we had to handle
239 * a signal. If so we can force a restart..
240 */
241 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
242 /* See if we were interrupted */
243 if (signal_pending(current)) {
244 sigset_t *sigset = &current->pending.signal;
245 if (sigismember (sigset, SIGKILL) ||
246 sigismember (sigset, SIGQUIT) ||
247 sigismember (sigset, SIGINT)) {
248 unlock_kernel();
249 return ERR_PTR(-ERESTARTNOINTR);
250 }
251 }
252 }
253 unlock_kernel();
254
255 /*
256 * If this dentry is unhashed, then we shouldn't honour this
257 * lookup even if the dentry is positive. Returning ENOENT here
258 * doesn't do the right thing for all system calls, but it should
259 * be OK for the operations we permit from an autofs.
260 */
261 if ( dentry->d_inode && d_unhashed(dentry) )
262 return ERR_PTR(-ENOENT);
263
264 return NULL;
265}
266
267static int autofs_root_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
268{
269 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
270 struct autofs_dirhash *dh = &sbi->dirhash;
271 struct autofs_dir_ent *ent;
272 unsigned int n;
273 int slsize;
274 struct autofs_symlink *sl;
275
276 DPRINTK(("autofs_root_symlink: %s <- ", symname));
277 autofs_say(dentry->d_name.name,dentry->d_name.len);
278
279 lock_kernel();
280 if ( !autofs_oz_mode(sbi) ) {
281 unlock_kernel();
282 return -EACCES;
283 }
284
285 if ( autofs_hash_lookup(dh, &dentry->d_name) ) {
286 unlock_kernel();
287 return -EEXIST;
288 }
289
290 n = find_first_zero_bit(sbi->symlink_bitmap,AUTOFS_MAX_SYMLINKS);
291 if ( n >= AUTOFS_MAX_SYMLINKS ) {
292 unlock_kernel();
293 return -ENOSPC;
294 }
295
296 set_bit(n,sbi->symlink_bitmap);
297 sl = &sbi->symlink[n];
298 sl->len = strlen(symname);
299 sl->data = kmalloc(slsize = sl->len+1, GFP_KERNEL);
300 if ( !sl->data ) {
301 clear_bit(n,sbi->symlink_bitmap);
302 unlock_kernel();
303 return -ENOSPC;
304 }
305
306 ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
307 if ( !ent ) {
308 kfree(sl->data);
309 clear_bit(n,sbi->symlink_bitmap);
310 unlock_kernel();
311 return -ENOSPC;
312 }
313
314 ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
315 if ( !ent->name ) {
316 kfree(sl->data);
317 kfree(ent);
318 clear_bit(n,sbi->symlink_bitmap);
319 unlock_kernel();
320 return -ENOSPC;
321 }
322
323 memcpy(sl->data,symname,slsize);
324 sl->mtime = get_seconds();
325
326 ent->ino = AUTOFS_FIRST_SYMLINK + n;
327 ent->hash = dentry->d_name.hash;
328 memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
329 ent->dentry = NULL; /* We don't keep the dentry for symlinks */
330
331 autofs_hash_insert(dh,ent);
332 d_instantiate(dentry, iget(dir->i_sb,ent->ino));
333 unlock_kernel();
334 return 0;
335}
336
337/*
338 * NOTE!
339 *
340 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
341 * that the file no longer exists. However, doing that means that the
342 * VFS layer can turn the dentry into a negative dentry, which we
343 * obviously do not want (we're dropping the entry not because it
344 * doesn't exist, but because it has timed out).
345 *
346 * Also see autofs_root_rmdir()..
347 */
348static int autofs_root_unlink(struct inode *dir, struct dentry *dentry)
349{
350 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
351 struct autofs_dirhash *dh = &sbi->dirhash;
352 struct autofs_dir_ent *ent;
353 unsigned int n;
354
355 /* This allows root to remove symlinks */
356 lock_kernel();
357 if ( !autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) ) {
358 unlock_kernel();
359 return -EACCES;
360 }
361
362 ent = autofs_hash_lookup(dh, &dentry->d_name);
363 if ( !ent ) {
364 unlock_kernel();
365 return -ENOENT;
366 }
367
368 n = ent->ino - AUTOFS_FIRST_SYMLINK;
369 if ( n >= AUTOFS_MAX_SYMLINKS ) {
370 unlock_kernel();
371 return -EISDIR; /* It's a directory, dummy */
372 }
373 if ( !test_bit(n,sbi->symlink_bitmap) ) {
374 unlock_kernel();
375 return -EINVAL; /* Nonexistent symlink? Shouldn't happen */
376 }
377
378 dentry->d_time = (unsigned long)(struct autofs_dirhash *)NULL;
379 autofs_hash_delete(ent);
380 clear_bit(n,sbi->symlink_bitmap);
381 kfree(sbi->symlink[n].data);
382 d_drop(dentry);
383
384 unlock_kernel();
385 return 0;
386}
387
388static int autofs_root_rmdir(struct inode *dir, struct dentry *dentry)
389{
390 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
391 struct autofs_dirhash *dh = &sbi->dirhash;
392 struct autofs_dir_ent *ent;
393
394 lock_kernel();
395 if ( !autofs_oz_mode(sbi) ) {
396 unlock_kernel();
397 return -EACCES;
398 }
399
400 ent = autofs_hash_lookup(dh, &dentry->d_name);
401 if ( !ent ) {
402 unlock_kernel();
403 return -ENOENT;
404 }
405
406 if ( (unsigned int)ent->ino < AUTOFS_FIRST_DIR_INO ) {
407 unlock_kernel();
408 return -ENOTDIR; /* Not a directory */
409 }
410
411 if ( ent->dentry != dentry ) {
412 printk("autofs_rmdir: odentry != dentry for entry %s\n", dentry->d_name.name);
413 }
414
415 dentry->d_time = (unsigned long)(struct autofs_dir_ent *)NULL;
416 autofs_hash_delete(ent);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700417 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 d_drop(dentry);
419 unlock_kernel();
420
421 return 0;
422}
423
424static int autofs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode)
425{
426 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
427 struct autofs_dirhash *dh = &sbi->dirhash;
428 struct autofs_dir_ent *ent;
429 ino_t ino;
430
431 lock_kernel();
432 if ( !autofs_oz_mode(sbi) ) {
433 unlock_kernel();
434 return -EACCES;
435 }
436
437 ent = autofs_hash_lookup(dh, &dentry->d_name);
438 if ( ent ) {
439 unlock_kernel();
440 return -EEXIST;
441 }
442
443 if ( sbi->next_dir_ino < AUTOFS_FIRST_DIR_INO ) {
444 printk("autofs: Out of inode numbers -- what the heck did you do??\n");
445 unlock_kernel();
446 return -ENOSPC;
447 }
448 ino = sbi->next_dir_ino++;
449
450 ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
451 if ( !ent ) {
452 unlock_kernel();
453 return -ENOSPC;
454 }
455
456 ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
457 if ( !ent->name ) {
458 kfree(ent);
459 unlock_kernel();
460 return -ENOSPC;
461 }
462
463 ent->hash = dentry->d_name.hash;
464 memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
465 ent->ino = ino;
466 ent->dentry = dentry;
467 autofs_hash_insert(dh,ent);
468
Dave Hansend8c76e62006-09-30 23:29:04 -0700469 inc_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 d_instantiate(dentry, iget(dir->i_sb,ino));
471 unlock_kernel();
472
473 return 0;
474}
475
476/* Get/set timeout ioctl() operation */
477static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi,
478 unsigned long __user *p)
479{
480 unsigned long ntimeout;
481
482 if (get_user(ntimeout, p) ||
483 put_user(sbi->exp_timeout / HZ, p))
484 return -EFAULT;
485
486 if ( ntimeout > ULONG_MAX/HZ )
487 sbi->exp_timeout = 0;
488 else
489 sbi->exp_timeout = ntimeout * HZ;
490
491 return 0;
492}
493
494/* Return protocol version */
495static inline int autofs_get_protover(int __user *p)
496{
497 return put_user(AUTOFS_PROTO_VERSION, p);
498}
499
500/* Perform an expiry operation */
501static inline int autofs_expire_run(struct super_block *sb,
502 struct autofs_sb_info *sbi,
503 struct vfsmount *mnt,
504 struct autofs_packet_expire __user *pkt_p)
505{
506 struct autofs_dir_ent *ent;
507 struct autofs_packet_expire pkt;
508
509 memset(&pkt,0,sizeof pkt);
510
511 pkt.hdr.proto_version = AUTOFS_PROTO_VERSION;
512 pkt.hdr.type = autofs_ptype_expire;
513
514 if ( !sbi->exp_timeout ||
515 !(ent = autofs_expire(sb,sbi,mnt)) )
516 return -EAGAIN;
517
518 pkt.len = ent->len;
519 memcpy(pkt.name, ent->name, pkt.len);
520 pkt.name[pkt.len] = '\0';
521
522 if ( copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)) )
523 return -EFAULT;
524
525 return 0;
526}
527
528/*
529 * ioctl()'s on the root directory is the chief method for the daemon to
530 * generate kernel reactions
531 */
532static int autofs_root_ioctl(struct inode *inode, struct file *filp,
533 unsigned int cmd, unsigned long arg)
534{
535 struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
536 void __user *argp = (void __user *)arg;
537
538 DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,process_group(current)));
539
540 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
541 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
542 return -ENOTTY;
543
544 if ( !autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
545 return -EPERM;
546
547 switch(cmd) {
548 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
549 return autofs_wait_release(sbi,(autofs_wqt_t)arg,0);
550 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
551 return autofs_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
552 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
553 autofs_catatonic_mode(sbi);
554 return 0;
555 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
556 return autofs_get_protover(argp);
557 case AUTOFS_IOC_SETTIMEOUT:
558 return autofs_get_set_timeout(sbi, argp);
559 case AUTOFS_IOC_EXPIRE:
Josef "Jeff" Sipek81ed19b2006-12-08 02:36:46 -0800560 return autofs_expire_run(inode->i_sb, sbi, filp->f_path.mnt,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 argp);
562 default:
563 return -ENOSYS;
564 }
565}