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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 */
8
9#include <linux/module.h>
10#include <linux/time.h>
11#include <linux/buffer_head.h>
12#include "fat.h"
13
14/* Characters that are undesirable in an MS-DOS file name */
15static unsigned char bad_chars[] = "*?<>|\"";
16static unsigned char bad_if_strict[] = "+=,; ";
17
18/***** Formats an MS-DOS file name. Rejects invalid names. */
19static int msdos_format_name(const unsigned char *name, int len,
20 unsigned char *res, struct fat_mount_options *opts)
21 /*
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)
26 */
27{
28 unsigned char *walk;
29 unsigned char c;
30 int space;
31
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;
39 }
40 /*
41 * disallow names that _really_ start with a dot
42 */
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;
56 /*
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.
63 */
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;
70 }
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;
78 }
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;
98 }
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;
106 }
107 if (space)
108 return -EINVAL;
109 if (opts->name_check == 's' && len)
110 return -EINVAL;
111 }
112 while (walk - res < MSDOS_NAME)
113 *walk++ = ' ';
114
115 return 0;
116}
117
118/***** Locates a directory entry. Uses unformatted name. */
119static int msdos_find(struct inode *dir, const unsigned char *name, int len,
120 struct fat_slot_info *sinfo)
121{
122 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
123 unsigned char msdos_name[MSDOS_NAME];
124 int err;
125
126 err = msdos_format_name(name, len, msdos_name, &sbi->options);
127 if (err)
128 return -ENOENT;
129
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;
138 }
139 if (err)
140 brelse(sinfo->bh);
141 }
142 return err;
143}
144
145/*
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.
150 */
151static int msdos_hash(const struct dentry *dentry, struct qstr *qstr)
152{
153 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
154 unsigned char msdos_name[MSDOS_NAME];
155 int error;
156
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;
161}
162
163/*
164 * Compare two msdos names. If either of the names are invalid,
165 * we fall back to doing the standard name comparison.
166 */
167static int msdos_cmp(const struct dentry *parent, const struct dentry *dentry,
168 unsigned int len, const char *str, const struct qstr *name)
169{
170 struct fat_mount_options *options = &MSDOS_SB(parent->d_sb)->options;
171 unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
172 int error;
173
174 error = msdos_format_name(name->name, name->len, a_msdos_name, options);
175 if (error)
176 goto old_compare;
177 error = msdos_format_name(str, len, b_msdos_name, options);
178 if (error)
179 goto old_compare;
180 error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
181out:
182 return error;
183
184old_compare:
185 error = 1;
186 if (name->len == len)
187 error = memcmp(name->name, str, len);
188 goto out;
189}
190
191static const struct dentry_operations msdos_dentry_operations = {
192 .d_hash = msdos_hash,
193 .d_compare = msdos_cmp,
194};
195
196/*
197 * AV. Wrappers for FAT sb operations. Is it wise?
198 */
199
200/***** Get inode using directory and name */
201static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
202 unsigned int flags)
203{
204 struct super_block *sb = dir->i_sb;
205 struct fat_slot_info sinfo;
206 struct inode *inode;
207 int err;
208
209 mutex_lock(&MSDOS_SB(sb)->s_lock);
210 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
211 switch (err) {
212 case -ENOENT:
213 inode = NULL;
214 break;
215 case 0:
216 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
217 brelse(sinfo.bh);
218 break;
219 default:
220 inode = ERR_PTR(err);
221 }
222 mutex_unlock(&MSDOS_SB(sb)->s_lock);
223 return d_splice_alias(inode, dentry);
224}
225
226/***** Creates a directory entry (name is already formatted). */
227static int msdos_add_entry(struct inode *dir, const unsigned char *name,
228 int is_dir, int is_hid, int cluster,
229 struct timespec *ts, struct fat_slot_info *sinfo)
230{
231 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
232 struct msdos_dir_entry de;
233 __le16 time, date;
234 int err;
235
236 memcpy(de.name, name, MSDOS_NAME);
237 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
238 if (is_hid)
239 de.attr |= ATTR_HIDDEN;
240 de.lcase = 0;
241 fat_time_unix2fat(sbi, ts, &time, &date, NULL);
242 de.cdate = de.adate = 0;
243 de.ctime = 0;
244 de.ctime_cs = 0;
245 de.time = time;
246 de.date = date;
247 fat_set_start(&de, cluster);
248 de.size = 0;
249
250 err = fat_add_entries(dir, &de, 1, sinfo);
251 if (err)
252 return err;
253
254 dir->i_ctime = dir->i_mtime = *ts;
255 if (IS_DIRSYNC(dir))
256 (void)fat_sync_inode(dir);
257 else
258 mark_inode_dirty(dir);
259
260 return 0;
261}
262
263/***** Create a file */
264static int msdos_create(struct inode *dir, struct dentry *dentry, umode_t mode,
265 bool excl)
266{
267 struct super_block *sb = dir->i_sb;
268 struct inode *inode = NULL;
269 struct fat_slot_info sinfo;
270 struct timespec ts;
271 unsigned char msdos_name[MSDOS_NAME];
272 int err, is_hid;
273
274 mutex_lock(&MSDOS_SB(sb)->s_lock);
275
276 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
277 msdos_name, &MSDOS_SB(sb)->options);
278 if (err)
279 goto out;
280 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
281 /* Have to do it due to foo vs. .foo conflicts */
282 if (!fat_scan(dir, msdos_name, &sinfo)) {
283 brelse(sinfo.bh);
284 err = -EINVAL;
285 goto out;
286 }
287
288 ts = CURRENT_TIME_SEC;
289 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
290 if (err)
291 goto out;
292 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
293 brelse(sinfo.bh);
294 if (IS_ERR(inode)) {
295 err = PTR_ERR(inode);
296 goto out;
297 }
298 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
299 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
300
301 d_instantiate(dentry, inode);
302out:
303 mutex_unlock(&MSDOS_SB(sb)->s_lock);
304 if (!err)
305 err = fat_flush_inodes(sb, dir, inode);
306 return err;
307}
308
309/***** Remove a directory */
310static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
311{
312 struct super_block *sb = dir->i_sb;
313 struct inode *inode = dentry->d_inode;
314 struct fat_slot_info sinfo;
315 int err;
316
317 mutex_lock(&MSDOS_SB(sb)->s_lock);
318 /*
319 * Check whether the directory is not in use, then check
320 * whether it is empty.
321 */
322 err = fat_dir_empty(inode);
323 if (err)
324 goto out;
325 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
326 if (err)
327 goto out;
328
329 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
330 if (err)
331 goto out;
332 drop_nlink(dir);
333
334 clear_nlink(inode);
335 inode->i_ctime = CURRENT_TIME_SEC;
336 fat_detach(inode);
337out:
338 mutex_unlock(&MSDOS_SB(sb)->s_lock);
339 if (!err)
340 err = fat_flush_inodes(sb, dir, inode);
341
342 return err;
343}
344
345/***** Make a directory */
346static int msdos_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
347{
348 struct super_block *sb = dir->i_sb;
349 struct fat_slot_info sinfo;
350 struct inode *inode;
351 unsigned char msdos_name[MSDOS_NAME];
352 struct timespec ts;
353 int err, is_hid, cluster;
354
355 mutex_lock(&MSDOS_SB(sb)->s_lock);
356
357 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
358 msdos_name, &MSDOS_SB(sb)->options);
359 if (err)
360 goto out;
361 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
362 /* foo vs .foo situation */
363 if (!fat_scan(dir, msdos_name, &sinfo)) {
364 brelse(sinfo.bh);
365 err = -EINVAL;
366 goto out;
367 }
368
369 ts = CURRENT_TIME_SEC;
370 cluster = fat_alloc_new_dir(dir, &ts);
371 if (cluster < 0) {
372 err = cluster;
373 goto out;
374 }
375 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
376 if (err)
377 goto out_free;
378 inc_nlink(dir);
379
380 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
381 brelse(sinfo.bh);
382 if (IS_ERR(inode)) {
383 err = PTR_ERR(inode);
384 /* the directory was completed, just return a error */
385 goto out;
386 }
387 set_nlink(inode, 2);
388 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
389 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
390
391 d_instantiate(dentry, inode);
392
393 mutex_unlock(&MSDOS_SB(sb)->s_lock);
394 fat_flush_inodes(sb, dir, inode);
395 return 0;
396
397out_free:
398 fat_free_clusters(dir, cluster);
399out:
400 mutex_unlock(&MSDOS_SB(sb)->s_lock);
401 return err;
402}
403
404/***** Unlink a file */
405static int msdos_unlink(struct inode *dir, struct dentry *dentry)
406{
407 struct inode *inode = dentry->d_inode;
408 struct super_block *sb = inode->i_sb;
409 struct fat_slot_info sinfo;
410 int err;
411
412 mutex_lock(&MSDOS_SB(sb)->s_lock);
413 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
414 if (err)
415 goto out;
416
417 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
418 if (err)
419 goto out;
420 clear_nlink(inode);
421 inode->i_ctime = CURRENT_TIME_SEC;
422 fat_detach(inode);
423out:
424 mutex_unlock(&MSDOS_SB(sb)->s_lock);
425 if (!err)
426 err = fat_flush_inodes(sb, dir, inode);
427
428 return err;
429}
430
431static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
432 struct dentry *old_dentry,
433 struct inode *new_dir, unsigned char *new_name,
434 struct dentry *new_dentry, int is_hid)
435{
436 struct buffer_head *dotdot_bh;
437 struct msdos_dir_entry *dotdot_de;
438 struct inode *old_inode, *new_inode;
439 struct fat_slot_info old_sinfo, sinfo;
440 struct timespec ts;
441 loff_t new_i_pos;
442 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
443
444 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
445 old_inode = old_dentry->d_inode;
446 new_inode = new_dentry->d_inode;
447
448 err = fat_scan(old_dir, old_name, &old_sinfo);
449 if (err) {
450 err = -EIO;
451 goto out;
452 }
453
454 is_dir = S_ISDIR(old_inode->i_mode);
455 update_dotdot = (is_dir && old_dir != new_dir);
456 if (update_dotdot) {
457 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
458 err = -EIO;
459 goto out;
460 }
461 }
462
463 old_attrs = MSDOS_I(old_inode)->i_attrs;
464 err = fat_scan(new_dir, new_name, &sinfo);
465 if (!err) {
466 if (!new_inode) {
467 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
468 if (sinfo.de != old_sinfo.de) {
469 err = -EINVAL;
470 goto out;
471 }
472 if (is_hid)
473 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
474 else
475 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
476 if (IS_DIRSYNC(old_dir)) {
477 err = fat_sync_inode(old_inode);
478 if (err) {
479 MSDOS_I(old_inode)->i_attrs = old_attrs;
480 goto out;
481 }
482 } else
483 mark_inode_dirty(old_inode);
484
485 old_dir->i_version++;
486 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
487 if (IS_DIRSYNC(old_dir))
488 (void)fat_sync_inode(old_dir);
489 else
490 mark_inode_dirty(old_dir);
491 goto out;
492 }
493 }
494
495 ts = CURRENT_TIME_SEC;
496 if (new_inode) {
497 if (err)
498 goto out;
499 if (is_dir) {
500 err = fat_dir_empty(new_inode);
501 if (err)
502 goto out;
503 }
504 new_i_pos = MSDOS_I(new_inode)->i_pos;
505 fat_detach(new_inode);
506 } else {
507 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
508 &ts, &sinfo);
509 if (err)
510 goto out;
511 new_i_pos = sinfo.i_pos;
512 }
513 new_dir->i_version++;
514
515 fat_detach(old_inode);
516 fat_attach(old_inode, new_i_pos);
517 if (is_hid)
518 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
519 else
520 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
521 if (IS_DIRSYNC(new_dir)) {
522 err = fat_sync_inode(old_inode);
523 if (err)
524 goto error_inode;
525 } else
526 mark_inode_dirty(old_inode);
527
528 if (update_dotdot) {
529 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
530 mark_buffer_dirty_inode(dotdot_bh, old_inode);
531 if (IS_DIRSYNC(new_dir)) {
532 err = sync_dirty_buffer(dotdot_bh);
533 if (err)
534 goto error_dotdot;
535 }
536 drop_nlink(old_dir);
537 if (!new_inode)
538 inc_nlink(new_dir);
539 }
540
541 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
542 old_sinfo.bh = NULL;
543 if (err)
544 goto error_dotdot;
545 old_dir->i_version++;
546 old_dir->i_ctime = old_dir->i_mtime = ts;
547 if (IS_DIRSYNC(old_dir))
548 (void)fat_sync_inode(old_dir);
549 else
550 mark_inode_dirty(old_dir);
551
552 if (new_inode) {
553 drop_nlink(new_inode);
554 if (is_dir)
555 drop_nlink(new_inode);
556 new_inode->i_ctime = ts;
557 }
558out:
559 brelse(sinfo.bh);
560 brelse(dotdot_bh);
561 brelse(old_sinfo.bh);
562 return err;
563
564error_dotdot:
565 /* data cluster is shared, serious corruption */
566 corrupt = 1;
567
568 if (update_dotdot) {
569 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
570 mark_buffer_dirty_inode(dotdot_bh, old_inode);
571 corrupt |= sync_dirty_buffer(dotdot_bh);
572 }
573error_inode:
574 fat_detach(old_inode);
575 fat_attach(old_inode, old_sinfo.i_pos);
576 MSDOS_I(old_inode)->i_attrs = old_attrs;
577 if (new_inode) {
578 fat_attach(new_inode, new_i_pos);
579 if (corrupt)
580 corrupt |= fat_sync_inode(new_inode);
581 } else {
582 /*
583 * If new entry was not sharing the data cluster, it
584 * shouldn't be serious corruption.
585 */
586 int err2 = fat_remove_entries(new_dir, &sinfo);
587 if (corrupt)
588 corrupt |= err2;
589 sinfo.bh = NULL;
590 }
591 if (corrupt < 0) {
592 fat_fs_error(new_dir->i_sb,
593 "%s: Filesystem corrupted (i_pos %lld)",
594 __func__, sinfo.i_pos);
595 }
596 goto out;
597}
598
599/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
600static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
601 struct inode *new_dir, struct dentry *new_dentry)
602{
603 struct super_block *sb = old_dir->i_sb;
604 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
605 int err, is_hid;
606
607 mutex_lock(&MSDOS_SB(sb)->s_lock);
608
609 err = msdos_format_name(old_dentry->d_name.name,
610 old_dentry->d_name.len, old_msdos_name,
611 &MSDOS_SB(old_dir->i_sb)->options);
612 if (err)
613 goto out;
614 err = msdos_format_name(new_dentry->d_name.name,
615 new_dentry->d_name.len, new_msdos_name,
616 &MSDOS_SB(new_dir->i_sb)->options);
617 if (err)
618 goto out;
619
620 is_hid =
621 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
622
623 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
624 new_dir, new_msdos_name, new_dentry, is_hid);
625out:
626 mutex_unlock(&MSDOS_SB(sb)->s_lock);
627 if (!err)
628 err = fat_flush_inodes(sb, old_dir, new_dir);
629 return err;
630}
631
632static const struct inode_operations msdos_dir_inode_operations = {
633 .create = msdos_create,
634 .lookup = msdos_lookup,
635 .unlink = msdos_unlink,
636 .mkdir = msdos_mkdir,
637 .rmdir = msdos_rmdir,
638 .rename = msdos_rename,
639 .setattr = fat_setattr,
640 .getattr = fat_getattr,
641};
642
643static void setup(struct super_block *sb)
644{
645 MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
646 sb->s_d_op = &msdos_dentry_operations;
647 sb->s_flags |= MS_NOATIME;
648}
649
650static int msdos_fill_super(struct super_block *sb, void *data, int silent)
651{
652 return fat_fill_super(sb, data, silent, 0, setup);
653}
654
655static struct dentry *msdos_mount(struct file_system_type *fs_type,
656 int flags, const char *dev_name,
657 void *data)
658{
659 return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
660}
661
662static struct file_system_type msdos_fs_type = {
663 .owner = THIS_MODULE,
664 .name = "msdos",
665 .mount = msdos_mount,
666 .kill_sb = kill_block_super,
667 .fs_flags = FS_REQUIRES_DEV,
668};
669MODULE_ALIAS_FS("msdos");
670
671static int __init init_msdos_fs(void)
672{
673 return register_filesystem(&msdos_fs_type);
674}
675
676static void __exit exit_msdos_fs(void)
677{
678 unregister_filesystem(&msdos_fs_type);
679}
680
681MODULE_LICENSE("GPL");
682MODULE_AUTHOR("Werner Almesberger");
683MODULE_DESCRIPTION("MS-DOS filesystem support");
684
685module_init(init_msdos_fs)
686module_exit(exit_msdos_fs)
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 */
8
9#include <linux/module.h>
10#include <linux/time.h>
11#include <linux/buffer_head.h>
12#include "fat.h"
13
14/* Characters that are undesirable in an MS-DOS file name */
15static unsigned char bad_chars[] = "*?<>|\"";
16static unsigned char bad_if_strict[] = "+=,; ";
17
18/***** Formats an MS-DOS file name. Rejects invalid names. */
19static int msdos_format_name(const unsigned char *name, int len,
20 unsigned char *res, struct fat_mount_options *opts)
21 /*
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)
26 */
27{
28 unsigned char *walk;
29 unsigned char c;
30 int space;
31
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;
39 }
40 /*
41 * disallow names that _really_ start with a dot
42 */
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;
56 /*
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.
63 */
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;
70 }
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;
78 }
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;
98 }
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;
106 }
107 if (space)
108 return -EINVAL;
109 if (opts->name_check == 's' && len)
110 return -EINVAL;
111 }
112 while (walk - res < MSDOS_NAME)
113 *walk++ = ' ';
114
115 return 0;
116}
117
118/***** Locates a directory entry. Uses unformatted name. */
119static int msdos_find(struct inode *dir, const unsigned char *name, int len,
120 struct fat_slot_info *sinfo)
121{
122 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
123 unsigned char msdos_name[MSDOS_NAME];
124 int err;
125
126 err = msdos_format_name(name, len, msdos_name, &sbi->options);
127 if (err)
128 return -ENOENT;
129
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;
138 }
139 if (err)
140 brelse(sinfo->bh);
141 }
142 return err;
143}
144
145/*
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.
150 */
151static int msdos_hash(const struct dentry *dentry, const struct inode *inode,
152 struct qstr *qstr)
153{
154 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
155 unsigned char msdos_name[MSDOS_NAME];
156 int error;
157
158 error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
159 if (!error)
160 qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
161 return 0;
162}
163
164/*
165 * Compare two msdos names. If either of the names are invalid,
166 * we fall back to doing the standard name comparison.
167 */
168static int msdos_cmp(const struct dentry *parent, const struct inode *pinode,
169 const struct dentry *dentry, const struct inode *inode,
170 unsigned int len, const char *str, const struct qstr *name)
171{
172 struct fat_mount_options *options = &MSDOS_SB(parent->d_sb)->options;
173 unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
174 int error;
175
176 error = msdos_format_name(name->name, name->len, a_msdos_name, options);
177 if (error)
178 goto old_compare;
179 error = msdos_format_name(str, len, b_msdos_name, options);
180 if (error)
181 goto old_compare;
182 error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
183out:
184 return error;
185
186old_compare:
187 error = 1;
188 if (name->len == len)
189 error = memcmp(name->name, str, len);
190 goto out;
191}
192
193static const struct dentry_operations msdos_dentry_operations = {
194 .d_hash = msdos_hash,
195 .d_compare = msdos_cmp,
196};
197
198/*
199 * AV. Wrappers for FAT sb operations. Is it wise?
200 */
201
202/***** Get inode using directory and name */
203static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
204 struct nameidata *nd)
205{
206 struct super_block *sb = dir->i_sb;
207 struct fat_slot_info sinfo;
208 struct inode *inode;
209 int err;
210
211 lock_super(sb);
212 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
213 switch (err) {
214 case -ENOENT:
215 inode = NULL;
216 break;
217 case 0:
218 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
219 brelse(sinfo.bh);
220 break;
221 default:
222 inode = ERR_PTR(err);
223 }
224 unlock_super(sb);
225 return d_splice_alias(inode, dentry);
226}
227
228/***** Creates a directory entry (name is already formatted). */
229static int msdos_add_entry(struct inode *dir, const unsigned char *name,
230 int is_dir, int is_hid, int cluster,
231 struct timespec *ts, struct fat_slot_info *sinfo)
232{
233 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
234 struct msdos_dir_entry de;
235 __le16 time, date;
236 int err;
237
238 memcpy(de.name, name, MSDOS_NAME);
239 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
240 if (is_hid)
241 de.attr |= ATTR_HIDDEN;
242 de.lcase = 0;
243 fat_time_unix2fat(sbi, ts, &time, &date, NULL);
244 de.cdate = de.adate = 0;
245 de.ctime = 0;
246 de.ctime_cs = 0;
247 de.time = time;
248 de.date = date;
249 de.start = cpu_to_le16(cluster);
250 de.starthi = cpu_to_le16(cluster >> 16);
251 de.size = 0;
252
253 err = fat_add_entries(dir, &de, 1, sinfo);
254 if (err)
255 return err;
256
257 dir->i_ctime = dir->i_mtime = *ts;
258 if (IS_DIRSYNC(dir))
259 (void)fat_sync_inode(dir);
260 else
261 mark_inode_dirty(dir);
262
263 return 0;
264}
265
266/***** Create a file */
267static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
268 struct nameidata *nd)
269{
270 struct super_block *sb = dir->i_sb;
271 struct inode *inode = NULL;
272 struct fat_slot_info sinfo;
273 struct timespec ts;
274 unsigned char msdos_name[MSDOS_NAME];
275 int err, is_hid;
276
277 lock_super(sb);
278
279 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
280 msdos_name, &MSDOS_SB(sb)->options);
281 if (err)
282 goto out;
283 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
284 /* Have to do it due to foo vs. .foo conflicts */
285 if (!fat_scan(dir, msdos_name, &sinfo)) {
286 brelse(sinfo.bh);
287 err = -EINVAL;
288 goto out;
289 }
290
291 ts = CURRENT_TIME_SEC;
292 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
293 if (err)
294 goto out;
295 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
296 brelse(sinfo.bh);
297 if (IS_ERR(inode)) {
298 err = PTR_ERR(inode);
299 goto out;
300 }
301 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
302 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
303
304 d_instantiate(dentry, inode);
305out:
306 unlock_super(sb);
307 if (!err)
308 err = fat_flush_inodes(sb, dir, inode);
309 return err;
310}
311
312/***** Remove a directory */
313static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
314{
315 struct super_block *sb = dir->i_sb;
316 struct inode *inode = dentry->d_inode;
317 struct fat_slot_info sinfo;
318 int err;
319
320 lock_super(sb);
321 /*
322 * Check whether the directory is not in use, then check
323 * whether it is empty.
324 */
325 err = fat_dir_empty(inode);
326 if (err)
327 goto out;
328 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
329 if (err)
330 goto out;
331
332 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
333 if (err)
334 goto out;
335 drop_nlink(dir);
336
337 clear_nlink(inode);
338 inode->i_ctime = CURRENT_TIME_SEC;
339 fat_detach(inode);
340out:
341 unlock_super(sb);
342 if (!err)
343 err = fat_flush_inodes(sb, dir, inode);
344
345 return err;
346}
347
348/***** Make a directory */
349static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
350{
351 struct super_block *sb = dir->i_sb;
352 struct fat_slot_info sinfo;
353 struct inode *inode;
354 unsigned char msdos_name[MSDOS_NAME];
355 struct timespec ts;
356 int err, is_hid, cluster;
357
358 lock_super(sb);
359
360 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
361 msdos_name, &MSDOS_SB(sb)->options);
362 if (err)
363 goto out;
364 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
365 /* foo vs .foo situation */
366 if (!fat_scan(dir, msdos_name, &sinfo)) {
367 brelse(sinfo.bh);
368 err = -EINVAL;
369 goto out;
370 }
371
372 ts = CURRENT_TIME_SEC;
373 cluster = fat_alloc_new_dir(dir, &ts);
374 if (cluster < 0) {
375 err = cluster;
376 goto out;
377 }
378 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
379 if (err)
380 goto out_free;
381 inc_nlink(dir);
382
383 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
384 brelse(sinfo.bh);
385 if (IS_ERR(inode)) {
386 err = PTR_ERR(inode);
387 /* the directory was completed, just return a error */
388 goto out;
389 }
390 inode->i_nlink = 2;
391 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
392 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
393
394 d_instantiate(dentry, inode);
395
396 unlock_super(sb);
397 fat_flush_inodes(sb, dir, inode);
398 return 0;
399
400out_free:
401 fat_free_clusters(dir, cluster);
402out:
403 unlock_super(sb);
404 return err;
405}
406
407/***** Unlink a file */
408static int msdos_unlink(struct inode *dir, struct dentry *dentry)
409{
410 struct inode *inode = dentry->d_inode;
411 struct super_block *sb= inode->i_sb;
412 struct fat_slot_info sinfo;
413 int err;
414
415 lock_super(sb);
416 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
417 if (err)
418 goto out;
419
420 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
421 if (err)
422 goto out;
423 clear_nlink(inode);
424 inode->i_ctime = CURRENT_TIME_SEC;
425 fat_detach(inode);
426out:
427 unlock_super(sb);
428 if (!err)
429 err = fat_flush_inodes(sb, dir, inode);
430
431 return err;
432}
433
434static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
435 struct dentry *old_dentry,
436 struct inode *new_dir, unsigned char *new_name,
437 struct dentry *new_dentry, int is_hid)
438{
439 struct buffer_head *dotdot_bh;
440 struct msdos_dir_entry *dotdot_de;
441 struct inode *old_inode, *new_inode;
442 struct fat_slot_info old_sinfo, sinfo;
443 struct timespec ts;
444 loff_t dotdot_i_pos, new_i_pos;
445 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
446
447 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
448 old_inode = old_dentry->d_inode;
449 new_inode = new_dentry->d_inode;
450
451 err = fat_scan(old_dir, old_name, &old_sinfo);
452 if (err) {
453 err = -EIO;
454 goto out;
455 }
456
457 is_dir = S_ISDIR(old_inode->i_mode);
458 update_dotdot = (is_dir && old_dir != new_dir);
459 if (update_dotdot) {
460 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
461 &dotdot_i_pos) < 0) {
462 err = -EIO;
463 goto out;
464 }
465 }
466
467 old_attrs = MSDOS_I(old_inode)->i_attrs;
468 err = fat_scan(new_dir, new_name, &sinfo);
469 if (!err) {
470 if (!new_inode) {
471 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
472 if (sinfo.de != old_sinfo.de) {
473 err = -EINVAL;
474 goto out;
475 }
476 if (is_hid)
477 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
478 else
479 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
480 if (IS_DIRSYNC(old_dir)) {
481 err = fat_sync_inode(old_inode);
482 if (err) {
483 MSDOS_I(old_inode)->i_attrs = old_attrs;
484 goto out;
485 }
486 } else
487 mark_inode_dirty(old_inode);
488
489 old_dir->i_version++;
490 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
491 if (IS_DIRSYNC(old_dir))
492 (void)fat_sync_inode(old_dir);
493 else
494 mark_inode_dirty(old_dir);
495 goto out;
496 }
497 }
498
499 ts = CURRENT_TIME_SEC;
500 if (new_inode) {
501 if (err)
502 goto out;
503 if (is_dir) {
504 err = fat_dir_empty(new_inode);
505 if (err)
506 goto out;
507 }
508 new_i_pos = MSDOS_I(new_inode)->i_pos;
509 fat_detach(new_inode);
510 } else {
511 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
512 &ts, &sinfo);
513 if (err)
514 goto out;
515 new_i_pos = sinfo.i_pos;
516 }
517 new_dir->i_version++;
518
519 fat_detach(old_inode);
520 fat_attach(old_inode, new_i_pos);
521 if (is_hid)
522 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
523 else
524 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
525 if (IS_DIRSYNC(new_dir)) {
526 err = fat_sync_inode(old_inode);
527 if (err)
528 goto error_inode;
529 } else
530 mark_inode_dirty(old_inode);
531
532 if (update_dotdot) {
533 int start = MSDOS_I(new_dir)->i_logstart;
534 dotdot_de->start = cpu_to_le16(start);
535 dotdot_de->starthi = cpu_to_le16(start >> 16);
536 mark_buffer_dirty_inode(dotdot_bh, old_inode);
537 if (IS_DIRSYNC(new_dir)) {
538 err = sync_dirty_buffer(dotdot_bh);
539 if (err)
540 goto error_dotdot;
541 }
542 drop_nlink(old_dir);
543 if (!new_inode)
544 inc_nlink(new_dir);
545 }
546
547 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
548 old_sinfo.bh = NULL;
549 if (err)
550 goto error_dotdot;
551 old_dir->i_version++;
552 old_dir->i_ctime = old_dir->i_mtime = ts;
553 if (IS_DIRSYNC(old_dir))
554 (void)fat_sync_inode(old_dir);
555 else
556 mark_inode_dirty(old_dir);
557
558 if (new_inode) {
559 drop_nlink(new_inode);
560 if (is_dir)
561 drop_nlink(new_inode);
562 new_inode->i_ctime = ts;
563 }
564out:
565 brelse(sinfo.bh);
566 brelse(dotdot_bh);
567 brelse(old_sinfo.bh);
568 return err;
569
570error_dotdot:
571 /* data cluster is shared, serious corruption */
572 corrupt = 1;
573
574 if (update_dotdot) {
575 int start = MSDOS_I(old_dir)->i_logstart;
576 dotdot_de->start = cpu_to_le16(start);
577 dotdot_de->starthi = cpu_to_le16(start >> 16);
578 mark_buffer_dirty_inode(dotdot_bh, old_inode);
579 corrupt |= sync_dirty_buffer(dotdot_bh);
580 }
581error_inode:
582 fat_detach(old_inode);
583 fat_attach(old_inode, old_sinfo.i_pos);
584 MSDOS_I(old_inode)->i_attrs = old_attrs;
585 if (new_inode) {
586 fat_attach(new_inode, new_i_pos);
587 if (corrupt)
588 corrupt |= fat_sync_inode(new_inode);
589 } else {
590 /*
591 * If new entry was not sharing the data cluster, it
592 * shouldn't be serious corruption.
593 */
594 int err2 = fat_remove_entries(new_dir, &sinfo);
595 if (corrupt)
596 corrupt |= err2;
597 sinfo.bh = NULL;
598 }
599 if (corrupt < 0) {
600 fat_fs_error(new_dir->i_sb,
601 "%s: Filesystem corrupted (i_pos %lld)",
602 __func__, sinfo.i_pos);
603 }
604 goto out;
605}
606
607/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
608static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
609 struct inode *new_dir, struct dentry *new_dentry)
610{
611 struct super_block *sb = old_dir->i_sb;
612 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
613 int err, is_hid;
614
615 lock_super(sb);
616
617 err = msdos_format_name(old_dentry->d_name.name,
618 old_dentry->d_name.len, old_msdos_name,
619 &MSDOS_SB(old_dir->i_sb)->options);
620 if (err)
621 goto out;
622 err = msdos_format_name(new_dentry->d_name.name,
623 new_dentry->d_name.len, new_msdos_name,
624 &MSDOS_SB(new_dir->i_sb)->options);
625 if (err)
626 goto out;
627
628 is_hid =
629 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
630
631 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
632 new_dir, new_msdos_name, new_dentry, is_hid);
633out:
634 unlock_super(sb);
635 if (!err)
636 err = fat_flush_inodes(sb, old_dir, new_dir);
637 return err;
638}
639
640static const struct inode_operations msdos_dir_inode_operations = {
641 .create = msdos_create,
642 .lookup = msdos_lookup,
643 .unlink = msdos_unlink,
644 .mkdir = msdos_mkdir,
645 .rmdir = msdos_rmdir,
646 .rename = msdos_rename,
647 .setattr = fat_setattr,
648 .getattr = fat_getattr,
649};
650
651static void setup(struct super_block *sb)
652{
653 MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
654 sb->s_d_op = &msdos_dentry_operations;
655 sb->s_flags |= MS_NOATIME;
656}
657
658static int msdos_fill_super(struct super_block *sb, void *data, int silent)
659{
660 return fat_fill_super(sb, data, silent, 0, setup);
661}
662
663static struct dentry *msdos_mount(struct file_system_type *fs_type,
664 int flags, const char *dev_name,
665 void *data)
666{
667 return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
668}
669
670static struct file_system_type msdos_fs_type = {
671 .owner = THIS_MODULE,
672 .name = "msdos",
673 .mount = msdos_mount,
674 .kill_sb = kill_block_super,
675 .fs_flags = FS_REQUIRES_DEV,
676};
677
678static int __init init_msdos_fs(void)
679{
680 return register_filesystem(&msdos_fs_type);
681}
682
683static void __exit exit_msdos_fs(void)
684{
685 unregister_filesystem(&msdos_fs_type);
686}
687
688MODULE_LICENSE("GPL");
689MODULE_AUTHOR("Werner Almesberger");
690MODULE_DESCRIPTION("MS-DOS filesystem support");
691
692module_init(init_msdos_fs)
693module_exit(exit_msdos_fs)