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[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / fs / fat / namei_msdos.c
blobbbc94ae4fd77150203435058b79e46a03bfb40bc
1 /*
2 * linux/fs/msdos/namei.c
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 "fat.h"
14 /* Characters that are undesirable in an MS-DOS file name */
15 static unsigned char bad_chars[] = "*?<>|\"";
16 static unsigned char bad_if_strict[] = "+=,; ";
18 /***** Formats an MS-DOS file name. Rejects invalid names. */
19 static int msdos_format_name(const unsigned char *name, int len,
20 unsigned char *res, struct fat_mount_options *opts)
22 * name is the proposed name, len is its length, res is
23 * the resulting name, opts->name_check is either (r)elaxed,
24 * (n)ormal or (s)trict, opts->dotsOK allows dots at the
25 * beginning of name (for hidden files)
28 unsigned char *walk;
29 unsigned char c;
30 int space;
32 if (name[0] == '.') { /* dotfile because . and .. already done */
33 if (opts->dotsOK) {
34 /* Get rid of dot - test for it elsewhere */
35 name++;
36 len--;
37 } else
38 return -EINVAL;
41 * disallow names that _really_ start with a dot
43 space = 1;
44 c = 0;
45 for (walk = res; len && walk - res < 8; walk++) {
46 c = *name++;
47 len--;
48 if (opts->name_check != 'r' && strchr(bad_chars, c))
49 return -EINVAL;
50 if (opts->name_check == 's' && strchr(bad_if_strict, c))
51 return -EINVAL;
52 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
53 return -EINVAL;
54 if (c < ' ' || c == ':' || c == '\\')
55 return -EINVAL;
57 * 0xE5 is legal as a first character, but we must substitute
58 * 0x05 because 0xE5 marks deleted files. Yes, DOS really
59 * does this.
60 * It seems that Microsoft hacked DOS to support non-US
61 * characters after the 0xE5 character was already in use to
62 * mark deleted files.
64 if ((res == walk) && (c == 0xE5))
65 c = 0x05;
66 if (c == '.')
67 break;
68 space = (c == ' ');
69 *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
71 if (space)
72 return -EINVAL;
73 if (opts->name_check == 's' && len && c != '.') {
74 c = *name++;
75 len--;
76 if (c != '.')
77 return -EINVAL;
79 while (c != '.' && len--)
80 c = *name++;
81 if (c == '.') {
82 while (walk - res < 8)
83 *walk++ = ' ';
84 while (len > 0 && walk - res < MSDOS_NAME) {
85 c = *name++;
86 len--;
87 if (opts->name_check != 'r' && strchr(bad_chars, c))
88 return -EINVAL;
89 if (opts->name_check == 's' &&
90 strchr(bad_if_strict, c))
91 return -EINVAL;
92 if (c < ' ' || c == ':' || c == '\\')
93 return -EINVAL;
94 if (c == '.') {
95 if (opts->name_check == 's')
96 return -EINVAL;
97 break;
99 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
100 return -EINVAL;
101 space = c == ' ';
102 if (!opts->nocase && c >= 'a' && c <= 'z')
103 *walk++ = c - 32;
104 else
105 *walk++ = c;
107 if (space)
108 return -EINVAL;
109 if (opts->name_check == 's' && len)
110 return -EINVAL;
112 while (walk - res < MSDOS_NAME)
113 *walk++ = ' ';
115 return 0;
118 /***** Locates a directory entry. Uses unformatted name. */
119 static int msdos_find(struct inode *dir, const unsigned char *name, int len,
120 struct fat_slot_info *sinfo)
122 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
123 unsigned char msdos_name[MSDOS_NAME];
124 int err;
126 err = msdos_format_name(name, len, msdos_name, &sbi->options);
127 if (err)
128 return -ENOENT;
130 err = fat_scan(dir, msdos_name, sinfo);
131 if (!err && sbi->options.dotsOK) {
132 if (name[0] == '.') {
133 if (!(sinfo->de->attr & ATTR_HIDDEN))
134 err = -ENOENT;
135 } else {
136 if (sinfo->de->attr & ATTR_HIDDEN)
137 err = -ENOENT;
139 if (err)
140 brelse(sinfo->bh);
142 return err;
146 * Compute the hash for the msdos name corresponding to the dentry.
147 * Note: if the name is invalid, we leave the hash code unchanged so
148 * that the existing dentry can be used. The msdos fs routines will
149 * return ENOENT or EINVAL as appropriate.
151 static int msdos_hash(struct dentry *dentry, struct qstr *qstr)
153 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
154 unsigned char msdos_name[MSDOS_NAME];
155 int error;
157 error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
158 if (!error)
159 qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
160 return 0;
164 * Compare two msdos names. If either of the names are invalid,
165 * we fall back to doing the standard name comparison.
167 static int msdos_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
169 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
170 unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
171 int error;
173 error = msdos_format_name(a->name, a->len, a_msdos_name, options);
174 if (error)
175 goto old_compare;
176 error = msdos_format_name(b->name, b->len, b_msdos_name, options);
177 if (error)
178 goto old_compare;
179 error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
180 out:
181 return error;
183 old_compare:
184 error = 1;
185 if (a->len == b->len)
186 error = memcmp(a->name, b->name, a->len);
187 goto out;
190 static const struct dentry_operations msdos_dentry_operations = {
191 .d_hash = msdos_hash,
192 .d_compare = msdos_cmp,
196 * AV. Wrappers for FAT sb operations. Is it wise?
199 /***** Get inode using directory and name */
200 static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
201 struct nameidata *nd)
203 struct super_block *sb = dir->i_sb;
204 struct fat_slot_info sinfo;
205 struct inode *inode;
206 int err;
208 lock_super(sb);
210 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
211 if (err) {
212 if (err == -ENOENT) {
213 inode = NULL;
214 goto out;
216 goto error;
219 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
220 brelse(sinfo.bh);
221 if (IS_ERR(inode)) {
222 err = PTR_ERR(inode);
223 goto error;
225 out:
226 unlock_super(sb);
227 dentry->d_op = &msdos_dentry_operations;
228 dentry = d_splice_alias(inode, dentry);
229 if (dentry)
230 dentry->d_op = &msdos_dentry_operations;
231 return dentry;
233 error:
234 unlock_super(sb);
235 return ERR_PTR(err);
238 /***** Creates a directory entry (name is already formatted). */
239 static int msdos_add_entry(struct inode *dir, const unsigned char *name,
240 int is_dir, int is_hid, int cluster,
241 struct timespec *ts, struct fat_slot_info *sinfo)
243 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
244 struct msdos_dir_entry de;
245 __le16 time, date;
246 int err;
248 memcpy(de.name, name, MSDOS_NAME);
249 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
250 if (is_hid)
251 de.attr |= ATTR_HIDDEN;
252 de.lcase = 0;
253 fat_time_unix2fat(sbi, ts, &time, &date, NULL);
254 de.cdate = de.adate = 0;
255 de.ctime = 0;
256 de.ctime_cs = 0;
257 de.time = time;
258 de.date = date;
259 de.start = cpu_to_le16(cluster);
260 de.starthi = cpu_to_le16(cluster >> 16);
261 de.size = 0;
263 err = fat_add_entries(dir, &de, 1, sinfo);
264 if (err)
265 return err;
267 dir->i_ctime = dir->i_mtime = *ts;
268 if (IS_DIRSYNC(dir))
269 (void)fat_sync_inode(dir);
270 else
271 mark_inode_dirty(dir);
273 return 0;
276 /***** Create a file */
277 static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
278 struct nameidata *nd)
280 struct super_block *sb = dir->i_sb;
281 struct inode *inode = NULL;
282 struct fat_slot_info sinfo;
283 struct timespec ts;
284 unsigned char msdos_name[MSDOS_NAME];
285 int err, is_hid;
287 lock_super(sb);
289 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
290 msdos_name, &MSDOS_SB(sb)->options);
291 if (err)
292 goto out;
293 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
294 /* Have to do it due to foo vs. .foo conflicts */
295 if (!fat_scan(dir, msdos_name, &sinfo)) {
296 brelse(sinfo.bh);
297 err = -EINVAL;
298 goto out;
301 ts = CURRENT_TIME_SEC;
302 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
303 if (err)
304 goto out;
305 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
306 brelse(sinfo.bh);
307 if (IS_ERR(inode)) {
308 err = PTR_ERR(inode);
309 goto out;
311 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
312 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
314 d_instantiate(dentry, inode);
315 out:
316 unlock_super(sb);
317 if (!err)
318 err = fat_flush_inodes(sb, dir, inode);
319 return err;
322 /***** Remove a directory */
323 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
325 struct super_block *sb = dir->i_sb;
326 struct inode *inode = dentry->d_inode;
327 struct fat_slot_info sinfo;
328 int err;
330 lock_super(sb);
332 * Check whether the directory is not in use, then check
333 * whether it is empty.
335 err = fat_dir_empty(inode);
336 if (err)
337 goto out;
338 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
339 if (err)
340 goto out;
342 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
343 if (err)
344 goto out;
345 drop_nlink(dir);
347 clear_nlink(inode);
348 inode->i_ctime = CURRENT_TIME_SEC;
349 fat_detach(inode);
350 out:
351 unlock_super(sb);
352 if (!err)
353 err = fat_flush_inodes(sb, dir, inode);
355 return err;
358 /***** Make a directory */
359 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
361 struct super_block *sb = dir->i_sb;
362 struct fat_slot_info sinfo;
363 struct inode *inode;
364 unsigned char msdos_name[MSDOS_NAME];
365 struct timespec ts;
366 int err, is_hid, cluster;
368 lock_super(sb);
370 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
371 msdos_name, &MSDOS_SB(sb)->options);
372 if (err)
373 goto out;
374 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
375 /* foo vs .foo situation */
376 if (!fat_scan(dir, msdos_name, &sinfo)) {
377 brelse(sinfo.bh);
378 err = -EINVAL;
379 goto out;
382 ts = CURRENT_TIME_SEC;
383 cluster = fat_alloc_new_dir(dir, &ts);
384 if (cluster < 0) {
385 err = cluster;
386 goto out;
388 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
389 if (err)
390 goto out_free;
391 inc_nlink(dir);
393 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
394 brelse(sinfo.bh);
395 if (IS_ERR(inode)) {
396 err = PTR_ERR(inode);
397 /* the directory was completed, just return a error */
398 goto out;
400 inode->i_nlink = 2;
401 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
402 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
404 d_instantiate(dentry, inode);
406 unlock_super(sb);
407 fat_flush_inodes(sb, dir, inode);
408 return 0;
410 out_free:
411 fat_free_clusters(dir, cluster);
412 out:
413 unlock_super(sb);
414 return err;
417 /***** Unlink a file */
418 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
420 struct inode *inode = dentry->d_inode;
421 struct super_block *sb= inode->i_sb;
422 struct fat_slot_info sinfo;
423 int err;
425 lock_super(sb);
426 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
427 if (err)
428 goto out;
430 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
431 if (err)
432 goto out;
433 clear_nlink(inode);
434 inode->i_ctime = CURRENT_TIME_SEC;
435 fat_detach(inode);
436 out:
437 unlock_super(sb);
438 if (!err)
439 err = fat_flush_inodes(sb, dir, inode);
441 return err;
444 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
445 struct dentry *old_dentry,
446 struct inode *new_dir, unsigned char *new_name,
447 struct dentry *new_dentry, int is_hid)
449 struct buffer_head *dotdot_bh;
450 struct msdos_dir_entry *dotdot_de;
451 struct inode *old_inode, *new_inode;
452 struct fat_slot_info old_sinfo, sinfo;
453 struct timespec ts;
454 loff_t dotdot_i_pos, new_i_pos;
455 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
457 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
458 old_inode = old_dentry->d_inode;
459 new_inode = new_dentry->d_inode;
461 err = fat_scan(old_dir, old_name, &old_sinfo);
462 if (err) {
463 err = -EIO;
464 goto out;
467 is_dir = S_ISDIR(old_inode->i_mode);
468 update_dotdot = (is_dir && old_dir != new_dir);
469 if (update_dotdot) {
470 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
471 &dotdot_i_pos) < 0) {
472 err = -EIO;
473 goto out;
477 old_attrs = MSDOS_I(old_inode)->i_attrs;
478 err = fat_scan(new_dir, new_name, &sinfo);
479 if (!err) {
480 if (!new_inode) {
481 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
482 if (sinfo.de != old_sinfo.de) {
483 err = -EINVAL;
484 goto out;
486 if (is_hid)
487 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
488 else
489 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
490 if (IS_DIRSYNC(old_dir)) {
491 err = fat_sync_inode(old_inode);
492 if (err) {
493 MSDOS_I(old_inode)->i_attrs = old_attrs;
494 goto out;
496 } else
497 mark_inode_dirty(old_inode);
499 old_dir->i_version++;
500 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
501 if (IS_DIRSYNC(old_dir))
502 (void)fat_sync_inode(old_dir);
503 else
504 mark_inode_dirty(old_dir);
505 goto out;
509 ts = CURRENT_TIME_SEC;
510 if (new_inode) {
511 if (err)
512 goto out;
513 if (is_dir) {
514 err = fat_dir_empty(new_inode);
515 if (err)
516 goto out;
518 new_i_pos = MSDOS_I(new_inode)->i_pos;
519 fat_detach(new_inode);
520 } else {
521 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
522 &ts, &sinfo);
523 if (err)
524 goto out;
525 new_i_pos = sinfo.i_pos;
527 new_dir->i_version++;
529 fat_detach(old_inode);
530 fat_attach(old_inode, new_i_pos);
531 if (is_hid)
532 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
533 else
534 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
535 if (IS_DIRSYNC(new_dir)) {
536 err = fat_sync_inode(old_inode);
537 if (err)
538 goto error_inode;
539 } else
540 mark_inode_dirty(old_inode);
542 if (update_dotdot) {
543 int start = MSDOS_I(new_dir)->i_logstart;
544 dotdot_de->start = cpu_to_le16(start);
545 dotdot_de->starthi = cpu_to_le16(start >> 16);
546 mark_buffer_dirty_inode(dotdot_bh, old_inode);
547 if (IS_DIRSYNC(new_dir)) {
548 err = sync_dirty_buffer(dotdot_bh);
549 if (err)
550 goto error_dotdot;
552 drop_nlink(old_dir);
553 if (!new_inode)
554 inc_nlink(new_dir);
557 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
558 old_sinfo.bh = NULL;
559 if (err)
560 goto error_dotdot;
561 old_dir->i_version++;
562 old_dir->i_ctime = old_dir->i_mtime = ts;
563 if (IS_DIRSYNC(old_dir))
564 (void)fat_sync_inode(old_dir);
565 else
566 mark_inode_dirty(old_dir);
568 if (new_inode) {
569 drop_nlink(new_inode);
570 if (is_dir)
571 drop_nlink(new_inode);
572 new_inode->i_ctime = ts;
574 out:
575 brelse(sinfo.bh);
576 brelse(dotdot_bh);
577 brelse(old_sinfo.bh);
578 return err;
580 error_dotdot:
581 /* data cluster is shared, serious corruption */
582 corrupt = 1;
584 if (update_dotdot) {
585 int start = MSDOS_I(old_dir)->i_logstart;
586 dotdot_de->start = cpu_to_le16(start);
587 dotdot_de->starthi = cpu_to_le16(start >> 16);
588 mark_buffer_dirty_inode(dotdot_bh, old_inode);
589 corrupt |= sync_dirty_buffer(dotdot_bh);
591 error_inode:
592 fat_detach(old_inode);
593 fat_attach(old_inode, old_sinfo.i_pos);
594 MSDOS_I(old_inode)->i_attrs = old_attrs;
595 if (new_inode) {
596 fat_attach(new_inode, new_i_pos);
597 if (corrupt)
598 corrupt |= fat_sync_inode(new_inode);
599 } else {
601 * If new entry was not sharing the data cluster, it
602 * shouldn't be serious corruption.
604 int err2 = fat_remove_entries(new_dir, &sinfo);
605 if (corrupt)
606 corrupt |= err2;
607 sinfo.bh = NULL;
609 if (corrupt < 0) {
610 fat_fs_error(new_dir->i_sb,
611 "%s: Filesystem corrupted (i_pos %lld)",
612 __func__, sinfo.i_pos);
614 goto out;
617 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
618 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
619 struct inode *new_dir, struct dentry *new_dentry)
621 struct super_block *sb = old_dir->i_sb;
622 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
623 int err, is_hid;
625 lock_super(sb);
627 err = msdos_format_name(old_dentry->d_name.name,
628 old_dentry->d_name.len, old_msdos_name,
629 &MSDOS_SB(old_dir->i_sb)->options);
630 if (err)
631 goto out;
632 err = msdos_format_name(new_dentry->d_name.name,
633 new_dentry->d_name.len, new_msdos_name,
634 &MSDOS_SB(new_dir->i_sb)->options);
635 if (err)
636 goto out;
638 is_hid =
639 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
641 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
642 new_dir, new_msdos_name, new_dentry, is_hid);
643 out:
644 unlock_super(sb);
645 if (!err)
646 err = fat_flush_inodes(sb, old_dir, new_dir);
647 return err;
650 static const struct inode_operations msdos_dir_inode_operations = {
651 .create = msdos_create,
652 .lookup = msdos_lookup,
653 .unlink = msdos_unlink,
654 .mkdir = msdos_mkdir,
655 .rmdir = msdos_rmdir,
656 .rename = msdos_rename,
657 .setattr = fat_setattr,
658 .getattr = fat_getattr,
661 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
663 int res;
665 res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
666 if (res)
667 return res;
669 sb->s_flags |= MS_NOATIME;
670 sb->s_root->d_op = &msdos_dentry_operations;
671 return 0;
674 static int msdos_get_sb(struct file_system_type *fs_type,
675 int flags, const char *dev_name,
676 void *data, struct vfsmount *mnt)
678 return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super,
679 mnt);
682 static struct file_system_type msdos_fs_type = {
683 .owner = THIS_MODULE,
684 .name = "msdos",
685 .get_sb = msdos_get_sb,
686 .kill_sb = kill_block_super,
687 .fs_flags = FS_REQUIRES_DEV,
690 static int __init init_msdos_fs(void)
692 return register_filesystem(&msdos_fs_type);
695 static void __exit exit_msdos_fs(void)
697 unregister_filesystem(&msdos_fs_type);
700 MODULE_LICENSE("GPL");
701 MODULE_AUTHOR("Werner Almesberger");
702 MODULE_DESCRIPTION("MS-DOS filesystem support");
704 module_init(init_msdos_fs)
705 module_exit(exit_msdos_fs)