ia64/linux-2.6.18-xen.hg

view fs/msdos/namei.c @ 524:7f8b544237bf

netfront: Allow netfront in domain 0.

This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
children
line source
1 /*
2 * linux/fs/msdos/namei.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
6 * Rewritten for constant inumbers 1999 by Al Viro
7 */
9 #include <linux/module.h>
10 #include <linux/time.h>
11 #include <linux/buffer_head.h>
12 #include <linux/msdos_fs.h>
13 #include <linux/smp_lock.h>
15 /* Characters that are undesirable in an MS-DOS file name */
16 static unsigned char bad_chars[] = "*?<>|\"";
17 static unsigned char bad_if_strict_pc[] = "+=,; ";
18 /* GEMDOS is less restrictive */
19 static unsigned char bad_if_strict_atari[] = " ";
21 #define bad_if_strict(opts) \
22 ((opts)->atari ? bad_if_strict_atari : bad_if_strict_pc)
24 /***** Formats an MS-DOS file name. Rejects invalid names. */
25 static int msdos_format_name(const unsigned char *name, int len,
26 unsigned char *res, struct fat_mount_options *opts)
27 /*
28 * name is the proposed name, len is its length, res is
29 * the resulting name, opts->name_check is either (r)elaxed,
30 * (n)ormal or (s)trict, opts->dotsOK allows dots at the
31 * beginning of name (for hidden files)
32 */
33 {
34 unsigned char *walk;
35 unsigned char c;
36 int space;
38 if (name[0] == '.') { /* dotfile because . and .. already done */
39 if (opts->dotsOK) {
40 /* Get rid of dot - test for it elsewhere */
41 name++;
42 len--;
43 } else if (!opts->atari)
44 return -EINVAL;
45 }
46 /*
47 * disallow names that _really_ start with a dot for MS-DOS,
48 * GEMDOS does not care
49 */
50 space = !opts->atari;
51 c = 0;
52 for (walk = res; len && walk - res < 8; walk++) {
53 c = *name++;
54 len--;
55 if (opts->name_check != 'r' && strchr(bad_chars, c))
56 return -EINVAL;
57 if (opts->name_check == 's' && strchr(bad_if_strict(opts), c))
58 return -EINVAL;
59 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
60 return -EINVAL;
61 if (c < ' ' || c == ':' || c == '\\')
62 return -EINVAL;
63 /*
64 * 0xE5 is legal as a first character, but we must substitute
65 * 0x05 because 0xE5 marks deleted files. Yes, DOS really
66 * does this.
67 * It seems that Microsoft hacked DOS to support non-US
68 * characters after the 0xE5 character was already in use to
69 * mark deleted files.
70 */
71 if ((res == walk) && (c == 0xE5))
72 c = 0x05;
73 if (c == '.')
74 break;
75 space = (c == ' ');
76 *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
77 }
78 if (space)
79 return -EINVAL;
80 if (opts->name_check == 's' && len && c != '.') {
81 c = *name++;
82 len--;
83 if (c != '.')
84 return -EINVAL;
85 }
86 while (c != '.' && len--)
87 c = *name++;
88 if (c == '.') {
89 while (walk - res < 8)
90 *walk++ = ' ';
91 while (len > 0 && walk - res < MSDOS_NAME) {
92 c = *name++;
93 len--;
94 if (opts->name_check != 'r' && strchr(bad_chars, c))
95 return -EINVAL;
96 if (opts->name_check == 's' &&
97 strchr(bad_if_strict(opts), c))
98 return -EINVAL;
99 if (c < ' ' || c == ':' || c == '\\')
100 return -EINVAL;
101 if (c == '.') {
102 if (opts->name_check == 's')
103 return -EINVAL;
104 break;
105 }
106 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
107 return -EINVAL;
108 space = c == ' ';
109 if (!opts->nocase && c >= 'a' && c <= 'z')
110 *walk++ = c - 32;
111 else
112 *walk++ = c;
113 }
114 if (space)
115 return -EINVAL;
116 if (opts->name_check == 's' && len)
117 return -EINVAL;
118 }
119 while (walk - res < MSDOS_NAME)
120 *walk++ = ' ';
122 return 0;
123 }
125 /***** Locates a directory entry. Uses unformatted name. */
126 static int msdos_find(struct inode *dir, const unsigned char *name, int len,
127 struct fat_slot_info *sinfo)
128 {
129 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
130 unsigned char msdos_name[MSDOS_NAME];
131 int err;
133 err = msdos_format_name(name, len, msdos_name, &sbi->options);
134 if (err)
135 return -ENOENT;
137 err = fat_scan(dir, msdos_name, sinfo);
138 if (!err && sbi->options.dotsOK) {
139 if (name[0] == '.') {
140 if (!(sinfo->de->attr & ATTR_HIDDEN))
141 err = -ENOENT;
142 } else {
143 if (sinfo->de->attr & ATTR_HIDDEN)
144 err = -ENOENT;
145 }
146 if (err)
147 brelse(sinfo->bh);
148 }
149 return err;
150 }
152 /*
153 * Compute the hash for the msdos name corresponding to the dentry.
154 * Note: if the name is invalid, we leave the hash code unchanged so
155 * that the existing dentry can be used. The msdos fs routines will
156 * return ENOENT or EINVAL as appropriate.
157 */
158 static int msdos_hash(struct dentry *dentry, struct qstr *qstr)
159 {
160 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
161 unsigned char msdos_name[MSDOS_NAME];
162 int error;
164 error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
165 if (!error)
166 qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
167 return 0;
168 }
170 /*
171 * Compare two msdos names. If either of the names are invalid,
172 * we fall back to doing the standard name comparison.
173 */
174 static int msdos_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
175 {
176 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
177 unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
178 int error;
180 error = msdos_format_name(a->name, a->len, a_msdos_name, options);
181 if (error)
182 goto old_compare;
183 error = msdos_format_name(b->name, b->len, b_msdos_name, options);
184 if (error)
185 goto old_compare;
186 error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
187 out:
188 return error;
190 old_compare:
191 error = 1;
192 if (a->len == b->len)
193 error = memcmp(a->name, b->name, a->len);
194 goto out;
195 }
197 static struct dentry_operations msdos_dentry_operations = {
198 .d_hash = msdos_hash,
199 .d_compare = msdos_cmp,
200 };
202 /*
203 * AV. Wrappers for FAT sb operations. Is it wise?
204 */
206 /***** Get inode using directory and name */
207 static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
208 struct nameidata *nd)
209 {
210 struct super_block *sb = dir->i_sb;
211 struct fat_slot_info sinfo;
212 struct inode *inode = NULL;
213 int res;
215 dentry->d_op = &msdos_dentry_operations;
217 lock_kernel();
218 res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
219 if (res == -ENOENT)
220 goto add;
221 if (res < 0)
222 goto out;
223 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
224 brelse(sinfo.bh);
225 if (IS_ERR(inode)) {
226 res = PTR_ERR(inode);
227 goto out;
228 }
229 add:
230 res = 0;
231 dentry = d_splice_alias(inode, dentry);
232 if (dentry)
233 dentry->d_op = &msdos_dentry_operations;
234 out:
235 unlock_kernel();
236 if (!res)
237 return dentry;
238 return ERR_PTR(res);
239 }
241 /***** Creates a directory entry (name is already formatted). */
242 static int msdos_add_entry(struct inode *dir, const unsigned char *name,
243 int is_dir, int is_hid, int cluster,
244 struct timespec *ts, struct fat_slot_info *sinfo)
245 {
246 struct msdos_dir_entry de;
247 __le16 time, date;
248 int err;
250 memcpy(de.name, name, MSDOS_NAME);
251 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
252 if (is_hid)
253 de.attr |= ATTR_HIDDEN;
254 de.lcase = 0;
255 fat_date_unix2dos(ts->tv_sec, &time, &date);
256 de.cdate = de.adate = 0;
257 de.ctime = 0;
258 de.ctime_cs = 0;
259 de.time = time;
260 de.date = date;
261 de.start = cpu_to_le16(cluster);
262 de.starthi = cpu_to_le16(cluster >> 16);
263 de.size = 0;
265 err = fat_add_entries(dir, &de, 1, sinfo);
266 if (err)
267 return err;
269 dir->i_ctime = dir->i_mtime = *ts;
270 if (IS_DIRSYNC(dir))
271 (void)fat_sync_inode(dir);
272 else
273 mark_inode_dirty(dir);
275 return 0;
276 }
278 /***** Create a file */
279 static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
280 struct nameidata *nd)
281 {
282 struct super_block *sb = dir->i_sb;
283 struct inode *inode;
284 struct fat_slot_info sinfo;
285 struct timespec ts;
286 unsigned char msdos_name[MSDOS_NAME];
287 int err, is_hid;
289 lock_kernel();
291 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
292 msdos_name, &MSDOS_SB(sb)->options);
293 if (err)
294 goto out;
295 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
296 /* Have to do it due to foo vs. .foo conflicts */
297 if (!fat_scan(dir, msdos_name, &sinfo)) {
298 brelse(sinfo.bh);
299 err = -EINVAL;
300 goto out;
301 }
303 ts = CURRENT_TIME_SEC;
304 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
305 if (err)
306 goto out;
307 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
308 brelse(sinfo.bh);
309 if (IS_ERR(inode)) {
310 err = PTR_ERR(inode);
311 goto out;
312 }
313 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
314 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
316 d_instantiate(dentry, inode);
317 out:
318 unlock_kernel();
319 return err;
320 }
322 /***** Remove a directory */
323 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
324 {
325 struct inode *inode = dentry->d_inode;
326 struct fat_slot_info sinfo;
327 int err;
329 lock_kernel();
330 /*
331 * Check whether the directory is not in use, then check
332 * whether it is empty.
333 */
334 err = fat_dir_empty(inode);
335 if (err)
336 goto out;
337 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
338 if (err)
339 goto out;
341 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
342 if (err)
343 goto out;
344 dir->i_nlink--;
346 inode->i_nlink = 0;
347 inode->i_ctime = CURRENT_TIME_SEC;
348 fat_detach(inode);
349 out:
350 unlock_kernel();
352 return err;
353 }
355 /***** Make a directory */
356 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
357 {
358 struct super_block *sb = dir->i_sb;
359 struct fat_slot_info sinfo;
360 struct inode *inode;
361 unsigned char msdos_name[MSDOS_NAME];
362 struct timespec ts;
363 int err, is_hid, cluster;
365 lock_kernel();
367 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
368 msdos_name, &MSDOS_SB(sb)->options);
369 if (err)
370 goto out;
371 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
372 /* foo vs .foo situation */
373 if (!fat_scan(dir, msdos_name, &sinfo)) {
374 brelse(sinfo.bh);
375 err = -EINVAL;
376 goto out;
377 }
379 ts = CURRENT_TIME_SEC;
380 cluster = fat_alloc_new_dir(dir, &ts);
381 if (cluster < 0) {
382 err = cluster;
383 goto out;
384 }
385 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
386 if (err)
387 goto out_free;
388 dir->i_nlink++;
390 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
391 brelse(sinfo.bh);
392 if (IS_ERR(inode)) {
393 err = PTR_ERR(inode);
394 /* the directory was completed, just return a error */
395 goto out;
396 }
397 inode->i_nlink = 2;
398 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
399 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
401 d_instantiate(dentry, inode);
403 unlock_kernel();
404 return 0;
406 out_free:
407 fat_free_clusters(dir, cluster);
408 out:
409 unlock_kernel();
410 return err;
411 }
413 /***** Unlink a file */
414 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
415 {
416 struct inode *inode = dentry->d_inode;
417 struct fat_slot_info sinfo;
418 int err;
420 lock_kernel();
421 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
422 if (err)
423 goto out;
425 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
426 if (err)
427 goto out;
428 inode->i_nlink = 0;
429 inode->i_ctime = CURRENT_TIME_SEC;
430 fat_detach(inode);
431 out:
432 unlock_kernel();
434 return err;
435 }
437 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
438 struct dentry *old_dentry,
439 struct inode *new_dir, unsigned char *new_name,
440 struct dentry *new_dentry, int is_hid)
441 {
442 struct buffer_head *dotdot_bh;
443 struct msdos_dir_entry *dotdot_de;
444 struct inode *old_inode, *new_inode;
445 struct fat_slot_info old_sinfo, sinfo;
446 struct timespec ts;
447 loff_t dotdot_i_pos, new_i_pos;
448 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
450 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
451 old_inode = old_dentry->d_inode;
452 new_inode = new_dentry->d_inode;
454 err = fat_scan(old_dir, old_name, &old_sinfo);
455 if (err) {
456 err = -EIO;
457 goto out;
458 }
460 is_dir = S_ISDIR(old_inode->i_mode);
461 update_dotdot = (is_dir && old_dir != new_dir);
462 if (update_dotdot) {
463 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
464 &dotdot_i_pos) < 0) {
465 err = -EIO;
466 goto out;
467 }
468 }
470 old_attrs = MSDOS_I(old_inode)->i_attrs;
471 err = fat_scan(new_dir, new_name, &sinfo);
472 if (!err) {
473 if (!new_inode) {
474 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
475 if (sinfo.de != old_sinfo.de) {
476 err = -EINVAL;
477 goto out;
478 }
479 if (is_hid)
480 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
481 else
482 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
483 if (IS_DIRSYNC(old_dir)) {
484 err = fat_sync_inode(old_inode);
485 if (err) {
486 MSDOS_I(old_inode)->i_attrs = old_attrs;
487 goto out;
488 }
489 } else
490 mark_inode_dirty(old_inode);
492 old_dir->i_version++;
493 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
494 if (IS_DIRSYNC(old_dir))
495 (void)fat_sync_inode(old_dir);
496 else
497 mark_inode_dirty(old_dir);
498 goto out;
499 }
500 }
502 ts = CURRENT_TIME_SEC;
503 if (new_inode) {
504 if (err)
505 goto out;
506 if (is_dir) {
507 err = fat_dir_empty(new_inode);
508 if (err)
509 goto out;
510 }
511 new_i_pos = MSDOS_I(new_inode)->i_pos;
512 fat_detach(new_inode);
513 } else {
514 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
515 &ts, &sinfo);
516 if (err)
517 goto out;
518 new_i_pos = sinfo.i_pos;
519 }
520 new_dir->i_version++;
522 fat_detach(old_inode);
523 fat_attach(old_inode, new_i_pos);
524 if (is_hid)
525 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
526 else
527 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
528 if (IS_DIRSYNC(new_dir)) {
529 err = fat_sync_inode(old_inode);
530 if (err)
531 goto error_inode;
532 } else
533 mark_inode_dirty(old_inode);
535 if (update_dotdot) {
536 int start = MSDOS_I(new_dir)->i_logstart;
537 dotdot_de->start = cpu_to_le16(start);
538 dotdot_de->starthi = cpu_to_le16(start >> 16);
539 mark_buffer_dirty(dotdot_bh);
540 if (IS_DIRSYNC(new_dir)) {
541 err = sync_dirty_buffer(dotdot_bh);
542 if (err)
543 goto error_dotdot;
544 }
545 old_dir->i_nlink--;
546 if (!new_inode)
547 new_dir->i_nlink++;
548 }
550 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
551 old_sinfo.bh = NULL;
552 if (err)
553 goto error_dotdot;
554 old_dir->i_version++;
555 old_dir->i_ctime = old_dir->i_mtime = ts;
556 if (IS_DIRSYNC(old_dir))
557 (void)fat_sync_inode(old_dir);
558 else
559 mark_inode_dirty(old_dir);
561 if (new_inode) {
562 if (is_dir)
563 new_inode->i_nlink -= 2;
564 else
565 new_inode->i_nlink--;
566 new_inode->i_ctime = ts;
567 }
568 out:
569 brelse(sinfo.bh);
570 brelse(dotdot_bh);
571 brelse(old_sinfo.bh);
572 return err;
574 error_dotdot:
575 /* data cluster is shared, serious corruption */
576 corrupt = 1;
578 if (update_dotdot) {
579 int start = MSDOS_I(old_dir)->i_logstart;
580 dotdot_de->start = cpu_to_le16(start);
581 dotdot_de->starthi = cpu_to_le16(start >> 16);
582 mark_buffer_dirty(dotdot_bh);
583 corrupt |= sync_dirty_buffer(dotdot_bh);
584 }
585 error_inode:
586 fat_detach(old_inode);
587 fat_attach(old_inode, old_sinfo.i_pos);
588 MSDOS_I(old_inode)->i_attrs = old_attrs;
589 if (new_inode) {
590 fat_attach(new_inode, new_i_pos);
591 if (corrupt)
592 corrupt |= fat_sync_inode(new_inode);
593 } else {
594 /*
595 * If new entry was not sharing the data cluster, it
596 * shouldn't be serious corruption.
597 */
598 int err2 = fat_remove_entries(new_dir, &sinfo);
599 if (corrupt)
600 corrupt |= err2;
601 sinfo.bh = NULL;
602 }
603 if (corrupt < 0) {
604 fat_fs_panic(new_dir->i_sb,
605 "%s: Filesystem corrupted (i_pos %lld)",
606 __FUNCTION__, sinfo.i_pos);
607 }
608 goto out;
609 }
611 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
612 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
613 struct inode *new_dir, struct dentry *new_dentry)
614 {
615 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
616 int err, is_hid;
618 lock_kernel();
620 err = msdos_format_name(old_dentry->d_name.name,
621 old_dentry->d_name.len, old_msdos_name,
622 &MSDOS_SB(old_dir->i_sb)->options);
623 if (err)
624 goto out;
625 err = msdos_format_name(new_dentry->d_name.name,
626 new_dentry->d_name.len, new_msdos_name,
627 &MSDOS_SB(new_dir->i_sb)->options);
628 if (err)
629 goto out;
631 is_hid =
632 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
634 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
635 new_dir, new_msdos_name, new_dentry, is_hid);
636 out:
637 unlock_kernel();
638 return err;
639 }
641 static struct inode_operations msdos_dir_inode_operations = {
642 .create = msdos_create,
643 .lookup = msdos_lookup,
644 .unlink = msdos_unlink,
645 .mkdir = msdos_mkdir,
646 .rmdir = msdos_rmdir,
647 .rename = msdos_rename,
648 .setattr = fat_notify_change,
649 };
651 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
652 {
653 int res;
655 res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
656 if (res)
657 return res;
659 sb->s_flags |= MS_NOATIME;
660 sb->s_root->d_op = &msdos_dentry_operations;
661 return 0;
662 }
664 static int msdos_get_sb(struct file_system_type *fs_type,
665 int flags, const char *dev_name,
666 void *data, struct vfsmount *mnt)
667 {
668 return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super,
669 mnt);
670 }
672 static struct file_system_type msdos_fs_type = {
673 .owner = THIS_MODULE,
674 .name = "msdos",
675 .get_sb = msdos_get_sb,
676 .kill_sb = kill_block_super,
677 .fs_flags = FS_REQUIRES_DEV,
678 };
680 static int __init init_msdos_fs(void)
681 {
682 return register_filesystem(&msdos_fs_type);
683 }
685 static void __exit exit_msdos_fs(void)
686 {
687 unregister_filesystem(&msdos_fs_type);
688 }
690 MODULE_LICENSE("GPL");
691 MODULE_AUTHOR("Werner Almesberger");
692 MODULE_DESCRIPTION("MS-DOS filesystem support");
694 module_init(init_msdos_fs)
695 module_exit(exit_msdos_fs)