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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// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/msdos/namei.c
4 *
5 * Written 1992,1993 by Werner Almesberger
6 * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
7 * Rewritten for constant inumbers 1999 by Al Viro
8 */
9
10#include <linux/module.h>
11#include <linux/iversion.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(dentry, 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 *dentry,
168 unsigned int len, const char *str, const struct qstr *name)
169{
170 struct fat_mount_options *options = &MSDOS_SB(dentry->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 timespec64 *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 fat_truncate_time(dir, ts, S_CTIME|S_MTIME);
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 mnt_idmap *idmap, struct inode *dir,
265 struct dentry *dentry, umode_t mode, bool excl)
266{
267 struct super_block *sb = dir->i_sb;
268 struct inode *inode = NULL;
269 struct fat_slot_info sinfo;
270 struct timespec64 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(dir);
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 fat_truncate_time(inode, &ts, S_ATIME|S_CTIME|S_MTIME);
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 = d_inode(dentry);
314 struct fat_slot_info sinfo;
315 int err;
316
317 mutex_lock(&MSDOS_SB(sb)->s_lock);
318 err = fat_dir_empty(inode);
319 if (err)
320 goto out;
321 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
322 if (err)
323 goto out;
324
325 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
326 if (err)
327 goto out;
328 drop_nlink(dir);
329
330 clear_nlink(inode);
331 fat_truncate_time(inode, NULL, S_CTIME);
332 fat_detach(inode);
333out:
334 mutex_unlock(&MSDOS_SB(sb)->s_lock);
335 if (!err)
336 err = fat_flush_inodes(sb, dir, inode);
337
338 return err;
339}
340
341/***** Make a directory */
342static int msdos_mkdir(struct mnt_idmap *idmap, struct inode *dir,
343 struct dentry *dentry, umode_t mode)
344{
345 struct super_block *sb = dir->i_sb;
346 struct fat_slot_info sinfo;
347 struct inode *inode;
348 unsigned char msdos_name[MSDOS_NAME];
349 struct timespec64 ts;
350 int err, is_hid, cluster;
351
352 mutex_lock(&MSDOS_SB(sb)->s_lock);
353
354 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
355 msdos_name, &MSDOS_SB(sb)->options);
356 if (err)
357 goto out;
358 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
359 /* foo vs .foo situation */
360 if (!fat_scan(dir, msdos_name, &sinfo)) {
361 brelse(sinfo.bh);
362 err = -EINVAL;
363 goto out;
364 }
365
366 ts = current_time(dir);
367 cluster = fat_alloc_new_dir(dir, &ts);
368 if (cluster < 0) {
369 err = cluster;
370 goto out;
371 }
372 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
373 if (err)
374 goto out_free;
375 inc_nlink(dir);
376
377 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
378 brelse(sinfo.bh);
379 if (IS_ERR(inode)) {
380 err = PTR_ERR(inode);
381 /* the directory was completed, just return a error */
382 goto out;
383 }
384 set_nlink(inode, 2);
385 fat_truncate_time(inode, &ts, S_ATIME|S_CTIME|S_MTIME);
386 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
387
388 d_instantiate(dentry, inode);
389
390 mutex_unlock(&MSDOS_SB(sb)->s_lock);
391 fat_flush_inodes(sb, dir, inode);
392 return 0;
393
394out_free:
395 fat_free_clusters(dir, cluster);
396out:
397 mutex_unlock(&MSDOS_SB(sb)->s_lock);
398 return err;
399}
400
401/***** Unlink a file */
402static int msdos_unlink(struct inode *dir, struct dentry *dentry)
403{
404 struct inode *inode = d_inode(dentry);
405 struct super_block *sb = inode->i_sb;
406 struct fat_slot_info sinfo;
407 int err;
408
409 mutex_lock(&MSDOS_SB(sb)->s_lock);
410 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
411 if (err)
412 goto out;
413
414 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
415 if (err)
416 goto out;
417 clear_nlink(inode);
418 fat_truncate_time(inode, NULL, S_CTIME);
419 fat_detach(inode);
420out:
421 mutex_unlock(&MSDOS_SB(sb)->s_lock);
422 if (!err)
423 err = fat_flush_inodes(sb, dir, inode);
424
425 return err;
426}
427
428static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
429 struct dentry *old_dentry,
430 struct inode *new_dir, unsigned char *new_name,
431 struct dentry *new_dentry, int is_hid)
432{
433 struct buffer_head *dotdot_bh;
434 struct msdos_dir_entry *dotdot_de;
435 struct inode *old_inode, *new_inode;
436 struct fat_slot_info old_sinfo, sinfo;
437 struct timespec64 ts;
438 loff_t new_i_pos;
439 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
440
441 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
442 old_inode = d_inode(old_dentry);
443 new_inode = d_inode(new_dentry);
444
445 err = fat_scan(old_dir, old_name, &old_sinfo);
446 if (err) {
447 err = -EIO;
448 goto out;
449 }
450
451 is_dir = S_ISDIR(old_inode->i_mode);
452 update_dotdot = (is_dir && old_dir != new_dir);
453 if (update_dotdot) {
454 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
455 err = -EIO;
456 goto out;
457 }
458 }
459
460 old_attrs = MSDOS_I(old_inode)->i_attrs;
461 err = fat_scan(new_dir, new_name, &sinfo);
462 if (!err) {
463 if (!new_inode) {
464 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
465 if (sinfo.de != old_sinfo.de) {
466 err = -EINVAL;
467 goto out;
468 }
469 if (is_hid)
470 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
471 else
472 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
473 if (IS_DIRSYNC(old_dir)) {
474 err = fat_sync_inode(old_inode);
475 if (err) {
476 MSDOS_I(old_inode)->i_attrs = old_attrs;
477 goto out;
478 }
479 } else
480 mark_inode_dirty(old_inode);
481
482 inode_inc_iversion(old_dir);
483 fat_truncate_time(old_dir, NULL, S_CTIME|S_MTIME);
484 if (IS_DIRSYNC(old_dir))
485 (void)fat_sync_inode(old_dir);
486 else
487 mark_inode_dirty(old_dir);
488 goto out;
489 }
490 }
491
492 ts = current_time(old_inode);
493 if (new_inode) {
494 if (err)
495 goto out;
496 if (is_dir) {
497 err = fat_dir_empty(new_inode);
498 if (err)
499 goto out;
500 }
501 new_i_pos = MSDOS_I(new_inode)->i_pos;
502 fat_detach(new_inode);
503 } else {
504 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
505 &ts, &sinfo);
506 if (err)
507 goto out;
508 new_i_pos = sinfo.i_pos;
509 }
510 inode_inc_iversion(new_dir);
511
512 fat_detach(old_inode);
513 fat_attach(old_inode, new_i_pos);
514 if (is_hid)
515 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
516 else
517 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
518 if (IS_DIRSYNC(new_dir)) {
519 err = fat_sync_inode(old_inode);
520 if (err)
521 goto error_inode;
522 } else
523 mark_inode_dirty(old_inode);
524
525 if (update_dotdot) {
526 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
527 mark_buffer_dirty_inode(dotdot_bh, old_inode);
528 if (IS_DIRSYNC(new_dir)) {
529 err = sync_dirty_buffer(dotdot_bh);
530 if (err)
531 goto error_dotdot;
532 }
533 drop_nlink(old_dir);
534 if (!new_inode)
535 inc_nlink(new_dir);
536 }
537
538 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
539 old_sinfo.bh = NULL;
540 if (err)
541 goto error_dotdot;
542 inode_inc_iversion(old_dir);
543 fat_truncate_time(old_dir, &ts, S_CTIME|S_MTIME);
544 if (IS_DIRSYNC(old_dir))
545 (void)fat_sync_inode(old_dir);
546 else
547 mark_inode_dirty(old_dir);
548
549 if (new_inode) {
550 drop_nlink(new_inode);
551 if (is_dir)
552 drop_nlink(new_inode);
553 fat_truncate_time(new_inode, &ts, S_CTIME);
554 }
555out:
556 brelse(sinfo.bh);
557 brelse(dotdot_bh);
558 brelse(old_sinfo.bh);
559 return err;
560
561error_dotdot:
562 /* data cluster is shared, serious corruption */
563 corrupt = 1;
564
565 if (update_dotdot) {
566 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
567 mark_buffer_dirty_inode(dotdot_bh, old_inode);
568 corrupt |= sync_dirty_buffer(dotdot_bh);
569 }
570error_inode:
571 fat_detach(old_inode);
572 fat_attach(old_inode, old_sinfo.i_pos);
573 MSDOS_I(old_inode)->i_attrs = old_attrs;
574 if (new_inode) {
575 fat_attach(new_inode, new_i_pos);
576 if (corrupt)
577 corrupt |= fat_sync_inode(new_inode);
578 } else {
579 /*
580 * If new entry was not sharing the data cluster, it
581 * shouldn't be serious corruption.
582 */
583 int err2 = fat_remove_entries(new_dir, &sinfo);
584 if (corrupt)
585 corrupt |= err2;
586 sinfo.bh = NULL;
587 }
588 if (corrupt < 0) {
589 fat_fs_error(new_dir->i_sb,
590 "%s: Filesystem corrupted (i_pos %lld)",
591 __func__, sinfo.i_pos);
592 }
593 goto out;
594}
595
596/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
597static int msdos_rename(struct mnt_idmap *idmap,
598 struct inode *old_dir, struct dentry *old_dentry,
599 struct inode *new_dir, struct dentry *new_dentry,
600 unsigned int flags)
601{
602 struct super_block *sb = old_dir->i_sb;
603 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
604 int err, is_hid;
605
606 if (flags & ~RENAME_NOREPLACE)
607 return -EINVAL;
608
609 mutex_lock(&MSDOS_SB(sb)->s_lock);
610
611 err = msdos_format_name(old_dentry->d_name.name,
612 old_dentry->d_name.len, old_msdos_name,
613 &MSDOS_SB(old_dir->i_sb)->options);
614 if (err)
615 goto out;
616 err = msdos_format_name(new_dentry->d_name.name,
617 new_dentry->d_name.len, new_msdos_name,
618 &MSDOS_SB(new_dir->i_sb)->options);
619 if (err)
620 goto out;
621
622 is_hid =
623 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
624
625 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
626 new_dir, new_msdos_name, new_dentry, is_hid);
627out:
628 mutex_unlock(&MSDOS_SB(sb)->s_lock);
629 if (!err)
630 err = fat_flush_inodes(sb, old_dir, new_dir);
631 return err;
632}
633
634static const struct inode_operations msdos_dir_inode_operations = {
635 .create = msdos_create,
636 .lookup = msdos_lookup,
637 .unlink = msdos_unlink,
638 .mkdir = msdos_mkdir,
639 .rmdir = msdos_rmdir,
640 .rename = msdos_rename,
641 .setattr = fat_setattr,
642 .getattr = fat_getattr,
643 .update_time = fat_update_time,
644};
645
646static void setup(struct super_block *sb)
647{
648 MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
649 sb->s_d_op = &msdos_dentry_operations;
650 sb->s_flags |= SB_NOATIME;
651}
652
653static int msdos_fill_super(struct super_block *sb, struct fs_context *fc)
654{
655 return fat_fill_super(sb, fc, setup);
656}
657
658static int msdos_get_tree(struct fs_context *fc)
659{
660 return get_tree_bdev(fc, msdos_fill_super);
661}
662
663static int msdos_parse_param(struct fs_context *fc, struct fs_parameter *param)
664{
665 return fat_parse_param(fc, param, false);
666}
667
668static const struct fs_context_operations msdos_context_ops = {
669 .parse_param = msdos_parse_param,
670 .get_tree = msdos_get_tree,
671 .reconfigure = fat_reconfigure,
672 .free = fat_free_fc,
673};
674
675static int msdos_init_fs_context(struct fs_context *fc)
676{
677 int err;
678
679 /* Initialize with is_vfat == false */
680 err = fat_init_fs_context(fc, false);
681 if (err)
682 return err;
683
684 fc->ops = &msdos_context_ops;
685 return 0;
686}
687
688static struct file_system_type msdos_fs_type = {
689 .owner = THIS_MODULE,
690 .name = "msdos",
691 .kill_sb = kill_block_super,
692 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
693 .init_fs_context = msdos_init_fs_context,
694 .parameters = fat_param_spec,
695};
696MODULE_ALIAS_FS("msdos");
697
698static int __init init_msdos_fs(void)
699{
700 return register_filesystem(&msdos_fs_type);
701}
702
703static void __exit exit_msdos_fs(void)
704{
705 unregister_filesystem(&msdos_fs_type);
706}
707
708MODULE_LICENSE("GPL");
709MODULE_AUTHOR("Werner Almesberger");
710MODULE_DESCRIPTION("MS-DOS filesystem support");
711
712module_init(init_msdos_fs)
713module_exit(exit_msdos_fs)