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Diffstat (limited to 'fs/fat/namei_msdos.c')
-rw-r--r--fs/fat/namei_msdos.c706
1 files changed, 706 insertions, 0 deletions
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
new file mode 100644
index 000000000000..7ba03a4acbe0
--- /dev/null
+++ b/fs/fat/namei_msdos.c
@@ -0,0 +1,706 @@
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 <linux/smp_lock.h>
13#include "fat.h"
14
15/* Characters that are undesirable in an MS-DOS file name */
16static unsigned char bad_chars[] = "*?<>|\"";
17static unsigned char bad_if_strict[] = "+=,; ";
18
19/***** Formats an MS-DOS file name. Rejects invalid names. */
20static int msdos_format_name(const unsigned char *name, int len,
21 unsigned char *res, struct fat_mount_options *opts)
22 /*
23 * name is the proposed name, len is its length, res is
24 * the resulting name, opts->name_check is either (r)elaxed,
25 * (n)ormal or (s)trict, opts->dotsOK allows dots at the
26 * beginning of name (for hidden files)
27 */
28{
29 unsigned char *walk;
30 unsigned char c;
31 int space;
32
33 if (name[0] == '.') { /* dotfile because . and .. already done */
34 if (opts->dotsOK) {
35 /* Get rid of dot - test for it elsewhere */
36 name++;
37 len--;
38 } else
39 return -EINVAL;
40 }
41 /*
42 * disallow names that _really_ start with a dot
43 */
44 space = 1;
45 c = 0;
46 for (walk = res; len && walk - res < 8; walk++) {
47 c = *name++;
48 len--;
49 if (opts->name_check != 'r' && strchr(bad_chars, c))
50 return -EINVAL;
51 if (opts->name_check == 's' && strchr(bad_if_strict, c))
52 return -EINVAL;
53 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
54 return -EINVAL;
55 if (c < ' ' || c == ':' || c == '\\')
56 return -EINVAL;
57 /*
58 * 0xE5 is legal as a first character, but we must substitute
59 * 0x05 because 0xE5 marks deleted files. Yes, DOS really
60 * does this.
61 * It seems that Microsoft hacked DOS to support non-US
62 * characters after the 0xE5 character was already in use to
63 * mark deleted files.
64 */
65 if ((res == walk) && (c == 0xE5))
66 c = 0x05;
67 if (c == '.')
68 break;
69 space = (c == ' ');
70 *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
71 }
72 if (space)
73 return -EINVAL;
74 if (opts->name_check == 's' && len && c != '.') {
75 c = *name++;
76 len--;
77 if (c != '.')
78 return -EINVAL;
79 }
80 while (c != '.' && len--)
81 c = *name++;
82 if (c == '.') {
83 while (walk - res < 8)
84 *walk++ = ' ';
85 while (len > 0 && walk - res < MSDOS_NAME) {
86 c = *name++;
87 len--;
88 if (opts->name_check != 'r' && strchr(bad_chars, c))
89 return -EINVAL;
90 if (opts->name_check == 's' &&
91 strchr(bad_if_strict, c))
92 return -EINVAL;
93 if (c < ' ' || c == ':' || c == '\\')
94 return -EINVAL;
95 if (c == '.') {
96 if (opts->name_check == 's')
97 return -EINVAL;
98 break;
99 }
100 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
101 return -EINVAL;
102 space = c == ' ';
103 if (!opts->nocase && c >= 'a' && c <= 'z')
104 *walk++ = c - 32;
105 else
106 *walk++ = c;
107 }
108 if (space)
109 return -EINVAL;
110 if (opts->name_check == 's' && len)
111 return -EINVAL;
112 }
113 while (walk - res < MSDOS_NAME)
114 *walk++ = ' ';
115
116 return 0;
117}
118
119/***** Locates a directory entry. Uses unformatted name. */
120static int msdos_find(struct inode *dir, const unsigned char *name, int len,
121 struct fat_slot_info *sinfo)
122{
123 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
124 unsigned char msdos_name[MSDOS_NAME];
125 int err;
126
127 err = msdos_format_name(name, len, msdos_name, &sbi->options);
128 if (err)
129 return -ENOENT;
130
131 err = fat_scan(dir, msdos_name, sinfo);
132 if (!err && sbi->options.dotsOK) {
133 if (name[0] == '.') {
134 if (!(sinfo->de->attr & ATTR_HIDDEN))
135 err = -ENOENT;
136 } else {
137 if (sinfo->de->attr & ATTR_HIDDEN)
138 err = -ENOENT;
139 }
140 if (err)
141 brelse(sinfo->bh);
142 }
143 return err;
144}
145
146/*
147 * Compute the hash for the msdos name corresponding to the dentry.
148 * Note: if the name is invalid, we leave the hash code unchanged so
149 * that the existing dentry can be used. The msdos fs routines will
150 * return ENOENT or EINVAL as appropriate.
151 */
152static int msdos_hash(struct dentry *dentry, 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(struct dentry *dentry, struct qstr *a, struct qstr *b)
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(a->name, a->len, a_msdos_name, options);
175 if (error)
176 goto old_compare;
177 error = msdos_format_name(b->name, b->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 (a->len == b->len)
187 error = memcmp(a->name, b->name, a->len);
188 goto out;
189}
190
191static 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 struct nameidata *nd)
203{
204 struct super_block *sb = dir->i_sb;
205 struct fat_slot_info sinfo;
206 struct inode *inode;
207 int err;
208
209 lock_super(sb);
210
211 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
212 if (err) {
213 if (err == -ENOENT) {
214 inode = NULL;
215 goto out;
216 }
217 goto error;
218 }
219
220 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
221 brelse(sinfo.bh);
222 if (IS_ERR(inode)) {
223 err = PTR_ERR(inode);
224 goto error;
225 }
226out:
227 unlock_super(sb);
228 dentry->d_op = &msdos_dentry_operations;
229 dentry = d_splice_alias(inode, dentry);
230 if (dentry)
231 dentry->d_op = &msdos_dentry_operations;
232 return dentry;
233
234error:
235 unlock_super(sb);
236 return ERR_PTR(err);
237}
238
239/***** Creates a directory entry (name is already formatted). */
240static int msdos_add_entry(struct inode *dir, const unsigned char *name,
241 int is_dir, int is_hid, int cluster,
242 struct timespec *ts, struct fat_slot_info *sinfo)
243{
244 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
245 struct msdos_dir_entry de;
246 __le16 time, date;
247 int err;
248
249 memcpy(de.name, name, MSDOS_NAME);
250 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
251 if (is_hid)
252 de.attr |= ATTR_HIDDEN;
253 de.lcase = 0;
254 fat_time_unix2fat(sbi, ts, &time, &date, NULL);
255 de.cdate = de.adate = 0;
256 de.ctime = 0;
257 de.ctime_cs = 0;
258 de.time = time;
259 de.date = date;
260 de.start = cpu_to_le16(cluster);
261 de.starthi = cpu_to_le16(cluster >> 16);
262 de.size = 0;
263
264 err = fat_add_entries(dir, &de, 1, sinfo);
265 if (err)
266 return err;
267
268 dir->i_ctime = dir->i_mtime = *ts;
269 if (IS_DIRSYNC(dir))
270 (void)fat_sync_inode(dir);
271 else
272 mark_inode_dirty(dir);
273
274 return 0;
275}
276
277/***** Create a file */
278static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
279 struct nameidata *nd)
280{
281 struct super_block *sb = dir->i_sb;
282 struct inode *inode = NULL;
283 struct fat_slot_info sinfo;
284 struct timespec ts;
285 unsigned char msdos_name[MSDOS_NAME];
286 int err, is_hid;
287
288 lock_super(sb);
289
290 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
291 msdos_name, &MSDOS_SB(sb)->options);
292 if (err)
293 goto out;
294 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
295 /* Have to do it due to foo vs. .foo conflicts */
296 if (!fat_scan(dir, msdos_name, &sinfo)) {
297 brelse(sinfo.bh);
298 err = -EINVAL;
299 goto out;
300 }
301
302 ts = CURRENT_TIME_SEC;
303 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
304 if (err)
305 goto out;
306 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
307 brelse(sinfo.bh);
308 if (IS_ERR(inode)) {
309 err = PTR_ERR(inode);
310 goto out;
311 }
312 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
313 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
314
315 d_instantiate(dentry, inode);
316out:
317 unlock_super(sb);
318 if (!err)
319 err = fat_flush_inodes(sb, dir, inode);
320 return err;
321}
322
323/***** Remove a directory */
324static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
325{
326 struct super_block *sb = dir->i_sb;
327 struct inode *inode = dentry->d_inode;
328 struct fat_slot_info sinfo;
329 int err;
330
331 lock_super(sb);
332 /*
333 * Check whether the directory is not in use, then check
334 * whether it is empty.
335 */
336 err = fat_dir_empty(inode);
337 if (err)
338 goto out;
339 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
340 if (err)
341 goto out;
342
343 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
344 if (err)
345 goto out;
346 drop_nlink(dir);
347
348 clear_nlink(inode);
349 inode->i_ctime = CURRENT_TIME_SEC;
350 fat_detach(inode);
351out:
352 unlock_super(sb);
353 if (!err)
354 err = fat_flush_inodes(sb, dir, inode);
355
356 return err;
357}
358
359/***** Make a directory */
360static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
361{
362 struct super_block *sb = dir->i_sb;
363 struct fat_slot_info sinfo;
364 struct inode *inode;
365 unsigned char msdos_name[MSDOS_NAME];
366 struct timespec ts;
367 int err, is_hid, cluster;
368
369 lock_super(sb);
370
371 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
372 msdos_name, &MSDOS_SB(sb)->options);
373 if (err)
374 goto out;
375 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
376 /* foo vs .foo situation */
377 if (!fat_scan(dir, msdos_name, &sinfo)) {
378 brelse(sinfo.bh);
379 err = -EINVAL;
380 goto out;
381 }
382
383 ts = CURRENT_TIME_SEC;
384 cluster = fat_alloc_new_dir(dir, &ts);
385 if (cluster < 0) {
386 err = cluster;
387 goto out;
388 }
389 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
390 if (err)
391 goto out_free;
392 inc_nlink(dir);
393
394 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
395 brelse(sinfo.bh);
396 if (IS_ERR(inode)) {
397 err = PTR_ERR(inode);
398 /* the directory was completed, just return a error */
399 goto out;
400 }
401 inode->i_nlink = 2;
402 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
403 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
404
405 d_instantiate(dentry, inode);
406
407 unlock_super(sb);
408 fat_flush_inodes(sb, dir, inode);
409 return 0;
410
411out_free:
412 fat_free_clusters(dir, cluster);
413out:
414 unlock_super(sb);
415 return err;
416}
417
418/***** Unlink a file */
419static int msdos_unlink(struct inode *dir, struct dentry *dentry)
420{
421 struct inode *inode = dentry->d_inode;
422 struct super_block *sb= inode->i_sb;
423 struct fat_slot_info sinfo;
424 int err;
425
426 lock_super(sb);
427 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
428 if (err)
429 goto out;
430
431 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
432 if (err)
433 goto out;
434 clear_nlink(inode);
435 inode->i_ctime = CURRENT_TIME_SEC;
436 fat_detach(inode);
437out:
438 unlock_super(sb);
439 if (!err)
440 err = fat_flush_inodes(sb, dir, inode);
441
442 return err;
443}
444
445static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
446 struct dentry *old_dentry,
447 struct inode *new_dir, unsigned char *new_name,
448 struct dentry *new_dentry, int is_hid)
449{
450 struct buffer_head *dotdot_bh;
451 struct msdos_dir_entry *dotdot_de;
452 struct inode *old_inode, *new_inode;
453 struct fat_slot_info old_sinfo, sinfo;
454 struct timespec ts;
455 loff_t dotdot_i_pos, new_i_pos;
456 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
457
458 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
459 old_inode = old_dentry->d_inode;
460 new_inode = new_dentry->d_inode;
461
462 err = fat_scan(old_dir, old_name, &old_sinfo);
463 if (err) {
464 err = -EIO;
465 goto out;
466 }
467
468 is_dir = S_ISDIR(old_inode->i_mode);
469 update_dotdot = (is_dir && old_dir != new_dir);
470 if (update_dotdot) {
471 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
472 &dotdot_i_pos) < 0) {
473 err = -EIO;
474 goto out;
475 }
476 }
477
478 old_attrs = MSDOS_I(old_inode)->i_attrs;
479 err = fat_scan(new_dir, new_name, &sinfo);
480 if (!err) {
481 if (!new_inode) {
482 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
483 if (sinfo.de != old_sinfo.de) {
484 err = -EINVAL;
485 goto out;
486 }
487 if (is_hid)
488 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
489 else
490 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
491 if (IS_DIRSYNC(old_dir)) {
492 err = fat_sync_inode(old_inode);
493 if (err) {
494 MSDOS_I(old_inode)->i_attrs = old_attrs;
495 goto out;
496 }
497 } else
498 mark_inode_dirty(old_inode);
499
500 old_dir->i_version++;
501 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
502 if (IS_DIRSYNC(old_dir))
503 (void)fat_sync_inode(old_dir);
504 else
505 mark_inode_dirty(old_dir);
506 goto out;
507 }
508 }
509
510 ts = CURRENT_TIME_SEC;
511 if (new_inode) {
512 if (err)
513 goto out;
514 if (is_dir) {
515 err = fat_dir_empty(new_inode);
516 if (err)
517 goto out;
518 }
519 new_i_pos = MSDOS_I(new_inode)->i_pos;
520 fat_detach(new_inode);
521 } else {
522 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
523 &ts, &sinfo);
524 if (err)
525 goto out;
526 new_i_pos = sinfo.i_pos;
527 }
528 new_dir->i_version++;
529
530 fat_detach(old_inode);
531 fat_attach(old_inode, new_i_pos);
532 if (is_hid)
533 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
534 else
535 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
536 if (IS_DIRSYNC(new_dir)) {
537 err = fat_sync_inode(old_inode);
538 if (err)
539 goto error_inode;
540 } else
541 mark_inode_dirty(old_inode);
542
543 if (update_dotdot) {
544 int start = MSDOS_I(new_dir)->i_logstart;
545 dotdot_de->start = cpu_to_le16(start);
546 dotdot_de->starthi = cpu_to_le16(start >> 16);
547 mark_buffer_dirty(dotdot_bh);
548 if (IS_DIRSYNC(new_dir)) {
549 err = sync_dirty_buffer(dotdot_bh);
550 if (err)
551 goto error_dotdot;
552 }
553 drop_nlink(old_dir);
554 if (!new_inode)
555 inc_nlink(new_dir);
556 }
557
558 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
559 old_sinfo.bh = NULL;
560 if (err)
561 goto error_dotdot;
562 old_dir->i_version++;
563 old_dir->i_ctime = old_dir->i_mtime = ts;
564 if (IS_DIRSYNC(old_dir))
565 (void)fat_sync_inode(old_dir);
566 else
567 mark_inode_dirty(old_dir);
568
569 if (new_inode) {
570 drop_nlink(new_inode);
571 if (is_dir)
572 drop_nlink(new_inode);
573 new_inode->i_ctime = ts;
574 }
575out:
576 brelse(sinfo.bh);
577 brelse(dotdot_bh);
578 brelse(old_sinfo.bh);
579 return err;
580
581error_dotdot:
582 /* data cluster is shared, serious corruption */
583 corrupt = 1;
584
585 if (update_dotdot) {
586 int start = MSDOS_I(old_dir)->i_logstart;
587 dotdot_de->start = cpu_to_le16(start);
588 dotdot_de->starthi = cpu_to_le16(start >> 16);
589 mark_buffer_dirty(dotdot_bh);
590 corrupt |= sync_dirty_buffer(dotdot_bh);
591 }
592error_inode:
593 fat_detach(old_inode);
594 fat_attach(old_inode, old_sinfo.i_pos);
595 MSDOS_I(old_inode)->i_attrs = old_attrs;
596 if (new_inode) {
597 fat_attach(new_inode, new_i_pos);
598 if (corrupt)
599 corrupt |= fat_sync_inode(new_inode);
600 } else {
601 /*
602 * If new entry was not sharing the data cluster, it
603 * shouldn't be serious corruption.
604 */
605 int err2 = fat_remove_entries(new_dir, &sinfo);
606 if (corrupt)
607 corrupt |= err2;
608 sinfo.bh = NULL;
609 }
610 if (corrupt < 0) {
611 fat_fs_panic(new_dir->i_sb,
612 "%s: Filesystem corrupted (i_pos %lld)",
613 __func__, sinfo.i_pos);
614 }
615 goto out;
616}
617
618/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
619static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
620 struct inode *new_dir, struct dentry *new_dentry)
621{
622 struct super_block *sb = old_dir->i_sb;
623 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
624 int err, is_hid;
625
626 lock_super(sb);
627
628 err = msdos_format_name(old_dentry->d_name.name,
629 old_dentry->d_name.len, old_msdos_name,
630 &MSDOS_SB(old_dir->i_sb)->options);
631 if (err)
632 goto out;
633 err = msdos_format_name(new_dentry->d_name.name,
634 new_dentry->d_name.len, new_msdos_name,
635 &MSDOS_SB(new_dir->i_sb)->options);
636 if (err)
637 goto out;
638
639 is_hid =
640 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
641
642 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
643 new_dir, new_msdos_name, new_dentry, is_hid);
644out:
645 unlock_super(sb);
646 if (!err)
647 err = fat_flush_inodes(sb, old_dir, new_dir);
648 return err;
649}
650
651static const struct inode_operations msdos_dir_inode_operations = {
652 .create = msdos_create,
653 .lookup = msdos_lookup,
654 .unlink = msdos_unlink,
655 .mkdir = msdos_mkdir,
656 .rmdir = msdos_rmdir,
657 .rename = msdos_rename,
658 .setattr = fat_setattr,
659 .getattr = fat_getattr,
660};
661
662static int msdos_fill_super(struct super_block *sb, void *data, int silent)
663{
664 int res;
665
666 res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
667 if (res)
668 return res;
669
670 sb->s_flags |= MS_NOATIME;
671 sb->s_root->d_op = &msdos_dentry_operations;
672 return 0;
673}
674
675static int msdos_get_sb(struct file_system_type *fs_type,
676 int flags, const char *dev_name,
677 void *data, struct vfsmount *mnt)
678{
679 return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super,
680 mnt);
681}
682
683static struct file_system_type msdos_fs_type = {
684 .owner = THIS_MODULE,
685 .name = "msdos",
686 .get_sb = msdos_get_sb,
687 .kill_sb = kill_block_super,
688 .fs_flags = FS_REQUIRES_DEV,
689};
690
691static int __init init_msdos_fs(void)
692{
693 return register_filesystem(&msdos_fs_type);
694}
695
696static void __exit exit_msdos_fs(void)
697{
698 unregister_filesystem(&msdos_fs_type);
699}
700
701MODULE_LICENSE("GPL");
702MODULE_AUTHOR("Werner Almesberger");
703MODULE_DESCRIPTION("MS-DOS filesystem support");
704
705module_init(init_msdos_fs)
706module_exit(exit_msdos_fs)
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-29 12:28:18 -0500