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1/*
2 * linux/fs/vfat/namei.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 *
6 * Windows95/Windows NT compatible extended MSDOS filesystem
7 * by Gordon Chaffee Copyright (C) 1995. Send bug reports for the
8 * VFAT filesystem to <chaffee@cs.berkeley.edu>. Specify
9 * what file operation caused you trouble and if you can duplicate
10 * the problem, send a script that demonstrates it.
11 *
12 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
13 *
14 * Support Multibyte characters and cleanup by
15 * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
16 */
17
18#include <linux/module.h>
19#include <linux/jiffies.h>
20#include <linux/ctype.h>
21#include <linux/slab.h>
22#include <linux/buffer_head.h>
23#include <linux/namei.h>
24#include "fat.h"
25
26/*
27 * If new entry was created in the parent, it could create the 8.3
28 * alias (the shortname of logname). So, the parent may have the
29 * negative-dentry which matches the created 8.3 alias.
30 *
31 * If it happened, the negative dentry isn't actually negative
32 * anymore. So, drop it.
33 */
34static int vfat_revalidate_shortname(struct dentry *dentry)
35{
36 int ret = 1;
37 spin_lock(&dentry->d_lock);
38 if (dentry->d_time != dentry->d_parent->d_inode->i_version)
39 ret = 0;
40 spin_unlock(&dentry->d_lock);
41 return ret;
42}
43
44static int vfat_revalidate(struct dentry *dentry, unsigned int flags)
45{
46 if (flags & LOOKUP_RCU)
47 return -ECHILD;
48
49 /* This is not negative dentry. Always valid. */
50 if (dentry->d_inode)
51 return 1;
52 return vfat_revalidate_shortname(dentry);
53}
54
55static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags)
56{
57 if (flags & LOOKUP_RCU)
58 return -ECHILD;
59
60 /*
61 * This is not negative dentry. Always valid.
62 *
63 * Note, rename() to existing directory entry will have ->d_inode,
64 * and will use existing name which isn't specified name by user.
65 *
66 * We may be able to drop this positive dentry here. But dropping
67 * positive dentry isn't good idea. So it's unsupported like
68 * rename("filename", "FILENAME") for now.
69 */
70 if (dentry->d_inode)
71 return 1;
72
73 /*
74 * This may be nfsd (or something), anyway, we can't see the
75 * intent of this. So, since this can be for creation, drop it.
76 */
77 if (!flags)
78 return 0;
79
80 /*
81 * Drop the negative dentry, in order to make sure to use the
82 * case sensitive name which is specified by user if this is
83 * for creation.
84 */
85 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
86 return 0;
87
88 return vfat_revalidate_shortname(dentry);
89}
90
91/* returns the length of a struct qstr, ignoring trailing dots */
92static unsigned int __vfat_striptail_len(unsigned int len, const char *name)
93{
94 while (len && name[len - 1] == '.')
95 len--;
96 return len;
97}
98
99static unsigned int vfat_striptail_len(const struct qstr *qstr)
100{
101 return __vfat_striptail_len(qstr->len, qstr->name);
102}
103
104/*
105 * Compute the hash for the vfat name corresponding to the dentry.
106 * Note: if the name is invalid, we leave the hash code unchanged so
107 * that the existing dentry can be used. The vfat fs routines will
108 * return ENOENT or EINVAL as appropriate.
109 */
110static int vfat_hash(const struct dentry *dentry, struct qstr *qstr)
111{
112 qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr));
113 return 0;
114}
115
116/*
117 * Compute the hash for the vfat name corresponding to the dentry.
118 * Note: if the name is invalid, we leave the hash code unchanged so
119 * that the existing dentry can be used. The vfat fs routines will
120 * return ENOENT or EINVAL as appropriate.
121 */
122static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr)
123{
124 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
125 const unsigned char *name;
126 unsigned int len;
127 unsigned long hash;
128
129 name = qstr->name;
130 len = vfat_striptail_len(qstr);
131
132 hash = init_name_hash();
133 while (len--)
134 hash = partial_name_hash(nls_tolower(t, *name++), hash);
135 qstr->hash = end_name_hash(hash);
136
137 return 0;
138}
139
140/*
141 * Case insensitive compare of two vfat names.
142 */
143static int vfat_cmpi(const struct dentry *parent, const struct dentry *dentry,
144 unsigned int len, const char *str, const struct qstr *name)
145{
146 struct nls_table *t = MSDOS_SB(parent->d_sb)->nls_io;
147 unsigned int alen, blen;
148
149 /* A filename cannot end in '.' or we treat it like it has none */
150 alen = vfat_striptail_len(name);
151 blen = __vfat_striptail_len(len, str);
152 if (alen == blen) {
153 if (nls_strnicmp(t, name->name, str, alen) == 0)
154 return 0;
155 }
156 return 1;
157}
158
159/*
160 * Case sensitive compare of two vfat names.
161 */
162static int vfat_cmp(const struct dentry *parent, const struct dentry *dentry,
163 unsigned int len, const char *str, const struct qstr *name)
164{
165 unsigned int alen, blen;
166
167 /* A filename cannot end in '.' or we treat it like it has none */
168 alen = vfat_striptail_len(name);
169 blen = __vfat_striptail_len(len, str);
170 if (alen == blen) {
171 if (strncmp(name->name, str, alen) == 0)
172 return 0;
173 }
174 return 1;
175}
176
177static const struct dentry_operations vfat_ci_dentry_ops = {
178 .d_revalidate = vfat_revalidate_ci,
179 .d_hash = vfat_hashi,
180 .d_compare = vfat_cmpi,
181};
182
183static const struct dentry_operations vfat_dentry_ops = {
184 .d_revalidate = vfat_revalidate,
185 .d_hash = vfat_hash,
186 .d_compare = vfat_cmp,
187};
188
189/* Characters that are undesirable in an MS-DOS file name */
190
191static inline wchar_t vfat_bad_char(wchar_t w)
192{
193 return (w < 0x0020)
194 || (w == '*') || (w == '?') || (w == '<') || (w == '>')
195 || (w == '|') || (w == '"') || (w == ':') || (w == '/')
196 || (w == '\\');
197}
198
199static inline wchar_t vfat_replace_char(wchar_t w)
200{
201 return (w == '[') || (w == ']') || (w == ';') || (w == ',')
202 || (w == '+') || (w == '=');
203}
204
205static wchar_t vfat_skip_char(wchar_t w)
206{
207 return (w == '.') || (w == ' ');
208}
209
210static inline int vfat_is_used_badchars(const wchar_t *s, int len)
211{
212 int i;
213
214 for (i = 0; i < len; i++)
215 if (vfat_bad_char(s[i]))
216 return -EINVAL;
217
218 if (s[i - 1] == ' ') /* last character cannot be space */
219 return -EINVAL;
220
221 return 0;
222}
223
224static int vfat_find_form(struct inode *dir, unsigned char *name)
225{
226 struct fat_slot_info sinfo;
227 int err = fat_scan(dir, name, &sinfo);
228 if (err)
229 return -ENOENT;
230 brelse(sinfo.bh);
231 return 0;
232}
233
234/*
235 * 1) Valid characters for the 8.3 format alias are any combination of
236 * letters, uppercase alphabets, digits, any of the
237 * following special characters:
238 * $ % ' ` - @ { } ~ ! # ( ) & _ ^
239 * In this case Longfilename is not stored in disk.
240 *
241 * WinNT's Extension:
242 * File name and extension name is contain uppercase/lowercase
243 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
244 *
245 * 2) File name is 8.3 format, but it contain the uppercase and
246 * lowercase char, muliti bytes char, etc. In this case numtail is not
247 * added, but Longfilename is stored.
248 *
249 * 3) When the one except for the above, or the following special
250 * character are contained:
251 * . [ ] ; , + =
252 * numtail is added, and Longfilename must be stored in disk .
253 */
254struct shortname_info {
255 unsigned char lower:1,
256 upper:1,
257 valid:1;
258};
259#define INIT_SHORTNAME_INFO(x) do { \
260 (x)->lower = 1; \
261 (x)->upper = 1; \
262 (x)->valid = 1; \
263} while (0)
264
265static inline int to_shortname_char(struct nls_table *nls,
266 unsigned char *buf, int buf_size,
267 wchar_t *src, struct shortname_info *info)
268{
269 int len;
270
271 if (vfat_skip_char(*src)) {
272 info->valid = 0;
273 return 0;
274 }
275 if (vfat_replace_char(*src)) {
276 info->valid = 0;
277 buf[0] = '_';
278 return 1;
279 }
280
281 len = nls->uni2char(*src, buf, buf_size);
282 if (len <= 0) {
283 info->valid = 0;
284 buf[0] = '_';
285 len = 1;
286 } else if (len == 1) {
287 unsigned char prev = buf[0];
288
289 if (buf[0] >= 0x7F) {
290 info->lower = 0;
291 info->upper = 0;
292 }
293
294 buf[0] = nls_toupper(nls, buf[0]);
295 if (isalpha(buf[0])) {
296 if (buf[0] == prev)
297 info->lower = 0;
298 else
299 info->upper = 0;
300 }
301 } else {
302 info->lower = 0;
303 info->upper = 0;
304 }
305
306 return len;
307}
308
309/*
310 * Given a valid longname, create a unique shortname. Make sure the
311 * shortname does not exist
312 * Returns negative number on error, 0 for a normal
313 * return, and 1 for valid shortname
314 */
315static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
316 wchar_t *uname, int ulen,
317 unsigned char *name_res, unsigned char *lcase)
318{
319 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;
320 wchar_t *ip, *ext_start, *end, *name_start;
321 unsigned char base[9], ext[4], buf[5], *p;
322 unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
323 int chl, chi;
324 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
325 int is_shortname;
326 struct shortname_info base_info, ext_info;
327
328 is_shortname = 1;
329 INIT_SHORTNAME_INFO(&base_info);
330 INIT_SHORTNAME_INFO(&ext_info);
331
332 /* Now, we need to create a shortname from the long name */
333 ext_start = end = &uname[ulen];
334 while (--ext_start >= uname) {
335 if (*ext_start == 0x002E) { /* is `.' */
336 if (ext_start == end - 1) {
337 sz = ulen;
338 ext_start = NULL;
339 }
340 break;
341 }
342 }
343
344 if (ext_start == uname - 1) {
345 sz = ulen;
346 ext_start = NULL;
347 } else if (ext_start) {
348 /*
349 * Names which start with a dot could be just
350 * an extension eg. "...test". In this case Win95
351 * uses the extension as the name and sets no extension.
352 */
353 name_start = &uname[0];
354 while (name_start < ext_start) {
355 if (!vfat_skip_char(*name_start))
356 break;
357 name_start++;
358 }
359 if (name_start != ext_start) {
360 sz = ext_start - uname;
361 ext_start++;
362 } else {
363 sz = ulen;
364 ext_start = NULL;
365 }
366 }
367
368 numtail_baselen = 6;
369 numtail2_baselen = 2;
370 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
371 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
372 ip, &base_info);
373 if (chl == 0)
374 continue;
375
376 if (baselen < 2 && (baselen + chl) > 2)
377 numtail2_baselen = baselen;
378 if (baselen < 6 && (baselen + chl) > 6)
379 numtail_baselen = baselen;
380 for (chi = 0; chi < chl; chi++) {
381 *p++ = charbuf[chi];
382 baselen++;
383 if (baselen >= 8)
384 break;
385 }
386 if (baselen >= 8) {
387 if ((chi < chl - 1) || (ip + 1) - uname < sz)
388 is_shortname = 0;
389 break;
390 }
391 }
392 if (baselen == 0) {
393 return -EINVAL;
394 }
395
396 extlen = 0;
397 if (ext_start) {
398 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
399 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
400 ip, &ext_info);
401 if (chl == 0)
402 continue;
403
404 if ((extlen + chl) > 3) {
405 is_shortname = 0;
406 break;
407 }
408 for (chi = 0; chi < chl; chi++) {
409 *p++ = charbuf[chi];
410 extlen++;
411 }
412 if (extlen >= 3) {
413 if (ip + 1 != end)
414 is_shortname = 0;
415 break;
416 }
417 }
418 }
419 ext[extlen] = '\0';
420 base[baselen] = '\0';
421
422 /* Yes, it can happen. ".\xe5" would do it. */
423 if (base[0] == DELETED_FLAG)
424 base[0] = 0x05;
425
426 /* OK, at this point we know that base is not longer than 8 symbols,
427 * ext is not longer than 3, base is nonempty, both don't contain
428 * any bad symbols (lowercase transformed to uppercase).
429 */
430
431 memset(name_res, ' ', MSDOS_NAME);
432 memcpy(name_res, base, baselen);
433 memcpy(name_res + 8, ext, extlen);
434 *lcase = 0;
435 if (is_shortname && base_info.valid && ext_info.valid) {
436 if (vfat_find_form(dir, name_res) == 0)
437 return -EEXIST;
438
439 if (opts->shortname & VFAT_SFN_CREATE_WIN95) {
440 return (base_info.upper && ext_info.upper);
441 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {
442 if ((base_info.upper || base_info.lower) &&
443 (ext_info.upper || ext_info.lower)) {
444 if (!base_info.upper && base_info.lower)
445 *lcase |= CASE_LOWER_BASE;
446 if (!ext_info.upper && ext_info.lower)
447 *lcase |= CASE_LOWER_EXT;
448 return 1;
449 }
450 return 0;
451 } else {
452 BUG();
453 }
454 }
455
456 if (opts->numtail == 0)
457 if (vfat_find_form(dir, name_res) < 0)
458 return 0;
459
460 /*
461 * Try to find a unique extension. This used to
462 * iterate through all possibilities sequentially,
463 * but that gave extremely bad performance. Windows
464 * only tries a few cases before using random
465 * values for part of the base.
466 */
467
468 if (baselen > 6) {
469 baselen = numtail_baselen;
470 name_res[7] = ' ';
471 }
472 name_res[baselen] = '~';
473 for (i = 1; i < 10; i++) {
474 name_res[baselen + 1] = i + '0';
475 if (vfat_find_form(dir, name_res) < 0)
476 return 0;
477 }
478
479 i = jiffies;
480 sz = (jiffies >> 16) & 0x7;
481 if (baselen > 2) {
482 baselen = numtail2_baselen;
483 name_res[7] = ' ';
484 }
485 name_res[baselen + 4] = '~';
486 name_res[baselen + 5] = '1' + sz;
487 while (1) {
488 snprintf(buf, sizeof(buf), "%04X", i & 0xffff);
489 memcpy(&name_res[baselen], buf, 4);
490 if (vfat_find_form(dir, name_res) < 0)
491 break;
492 i -= 11;
493 }
494 return 0;
495}
496
497/* Translate a string, including coded sequences into Unicode */
498static int
499xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
500 int *longlen, int *outlen, int escape, int utf8,
501 struct nls_table *nls)
502{
503 const unsigned char *ip;
504 unsigned char nc;
505 unsigned char *op;
506 unsigned int ec;
507 int i, k, fill;
508 int charlen;
509
510 if (utf8) {
511 *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN,
512 (wchar_t *) outname, FAT_LFN_LEN + 2);
513 if (*outlen < 0)
514 return *outlen;
515 else if (*outlen > FAT_LFN_LEN)
516 return -ENAMETOOLONG;
517
518 op = &outname[*outlen * sizeof(wchar_t)];
519 } else {
520 for (i = 0, ip = name, op = outname, *outlen = 0;
521 i < len && *outlen < FAT_LFN_LEN;
522 *outlen += 1) {
523 if (escape && (*ip == ':')) {
524 if (i > len - 5)
525 return -EINVAL;
526 ec = 0;
527 for (k = 1; k < 5; k++) {
528 nc = ip[k];
529 ec <<= 4;
530 if (nc >= '0' && nc <= '9') {
531 ec |= nc - '0';
532 continue;
533 }
534 if (nc >= 'a' && nc <= 'f') {
535 ec |= nc - ('a' - 10);
536 continue;
537 }
538 if (nc >= 'A' && nc <= 'F') {
539 ec |= nc - ('A' - 10);
540 continue;
541 }
542 return -EINVAL;
543 }
544 *op++ = ec & 0xFF;
545 *op++ = ec >> 8;
546 ip += 5;
547 i += 5;
548 } else {
549 charlen = nls->char2uni(ip, len - i,
550 (wchar_t *)op);
551 if (charlen < 0)
552 return -EINVAL;
553 ip += charlen;
554 i += charlen;
555 op += 2;
556 }
557 }
558 if (i < len)
559 return -ENAMETOOLONG;
560 }
561
562 *longlen = *outlen;
563 if (*outlen % 13) {
564 *op++ = 0;
565 *op++ = 0;
566 *outlen += 1;
567 if (*outlen % 13) {
568 fill = 13 - (*outlen % 13);
569 for (i = 0; i < fill; i++) {
570 *op++ = 0xff;
571 *op++ = 0xff;
572 }
573 *outlen += fill;
574 }
575 }
576
577 return 0;
578}
579
580static int vfat_build_slots(struct inode *dir, const unsigned char *name,
581 int len, int is_dir, int cluster,
582 struct timespec *ts,
583 struct msdos_dir_slot *slots, int *nr_slots)
584{
585 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
586 struct fat_mount_options *opts = &sbi->options;
587 struct msdos_dir_slot *ps;
588 struct msdos_dir_entry *de;
589 unsigned char cksum, lcase;
590 unsigned char msdos_name[MSDOS_NAME];
591 wchar_t *uname;
592 __le16 time, date;
593 u8 time_cs;
594 int err, ulen, usize, i;
595 loff_t offset;
596
597 *nr_slots = 0;
598
599 uname = __getname();
600 if (!uname)
601 return -ENOMEM;
602
603 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
604 opts->unicode_xlate, opts->utf8, sbi->nls_io);
605 if (err)
606 goto out_free;
607
608 err = vfat_is_used_badchars(uname, ulen);
609 if (err)
610 goto out_free;
611
612 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
613 msdos_name, &lcase);
614 if (err < 0)
615 goto out_free;
616 else if (err == 1) {
617 de = (struct msdos_dir_entry *)slots;
618 err = 0;
619 goto shortname;
620 }
621
622 /* build the entry of long file name */
623 cksum = fat_checksum(msdos_name);
624
625 *nr_slots = usize / 13;
626 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {
627 ps->id = i;
628 ps->attr = ATTR_EXT;
629 ps->reserved = 0;
630 ps->alias_checksum = cksum;
631 ps->start = 0;
632 offset = (i - 1) * 13;
633 fatwchar_to16(ps->name0_4, uname + offset, 5);
634 fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
635 fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
636 }
637 slots[0].id |= 0x40;
638 de = (struct msdos_dir_entry *)ps;
639
640shortname:
641 /* build the entry of 8.3 alias name */
642 (*nr_slots)++;
643 memcpy(de->name, msdos_name, MSDOS_NAME);
644 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
645 de->lcase = lcase;
646 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
647 de->time = de->ctime = time;
648 de->date = de->cdate = de->adate = date;
649 de->ctime_cs = time_cs;
650 fat_set_start(de, cluster);
651 de->size = 0;
652out_free:
653 __putname(uname);
654 return err;
655}
656
657static int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir,
658 int cluster, struct timespec *ts,
659 struct fat_slot_info *sinfo)
660{
661 struct msdos_dir_slot *slots;
662 unsigned int len;
663 int err, nr_slots;
664
665 len = vfat_striptail_len(qname);
666 if (len == 0)
667 return -ENOENT;
668
669 slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS);
670 if (slots == NULL)
671 return -ENOMEM;
672
673 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,
674 slots, &nr_slots);
675 if (err)
676 goto cleanup;
677
678 err = fat_add_entries(dir, slots, nr_slots, sinfo);
679 if (err)
680 goto cleanup;
681
682 /* update timestamp */
683 dir->i_ctime = dir->i_mtime = dir->i_atime = *ts;
684 if (IS_DIRSYNC(dir))
685 (void)fat_sync_inode(dir);
686 else
687 mark_inode_dirty(dir);
688cleanup:
689 kfree(slots);
690 return err;
691}
692
693static int vfat_find(struct inode *dir, struct qstr *qname,
694 struct fat_slot_info *sinfo)
695{
696 unsigned int len = vfat_striptail_len(qname);
697 if (len == 0)
698 return -ENOENT;
699 return fat_search_long(dir, qname->name, len, sinfo);
700}
701
702/*
703 * (nfsd's) anonymous disconnected dentry?
704 * NOTE: !IS_ROOT() is not anonymous (I.e. d_splice_alias() did the job).
705 */
706static int vfat_d_anon_disconn(struct dentry *dentry)
707{
708 return IS_ROOT(dentry) && (dentry->d_flags & DCACHE_DISCONNECTED);
709}
710
711static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
712 unsigned int flags)
713{
714 struct super_block *sb = dir->i_sb;
715 struct fat_slot_info sinfo;
716 struct inode *inode;
717 struct dentry *alias;
718 int err;
719
720 mutex_lock(&MSDOS_SB(sb)->s_lock);
721
722 err = vfat_find(dir, &dentry->d_name, &sinfo);
723 if (err) {
724 if (err == -ENOENT) {
725 inode = NULL;
726 goto out;
727 }
728 goto error;
729 }
730
731 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
732 brelse(sinfo.bh);
733 if (IS_ERR(inode)) {
734 err = PTR_ERR(inode);
735 goto error;
736 }
737
738 alias = d_find_alias(inode);
739 if (alias && !vfat_d_anon_disconn(alias)) {
740 /*
741 * This inode has non anonymous-DCACHE_DISCONNECTED
742 * dentry. This means, the user did ->lookup() by an
743 * another name (longname vs 8.3 alias of it) in past.
744 *
745 * Switch to new one for reason of locality if possible.
746 */
747 BUG_ON(d_unhashed(alias));
748 if (!S_ISDIR(inode->i_mode))
749 d_move(alias, dentry);
750 iput(inode);
751 mutex_unlock(&MSDOS_SB(sb)->s_lock);
752 return alias;
753 } else
754 dput(alias);
755
756out:
757 mutex_unlock(&MSDOS_SB(sb)->s_lock);
758 dentry->d_time = dentry->d_parent->d_inode->i_version;
759 dentry = d_splice_alias(inode, dentry);
760 if (dentry)
761 dentry->d_time = dentry->d_parent->d_inode->i_version;
762 return dentry;
763
764error:
765 mutex_unlock(&MSDOS_SB(sb)->s_lock);
766 return ERR_PTR(err);
767}
768
769static int vfat_create(struct inode *dir, struct dentry *dentry, umode_t mode,
770 bool excl)
771{
772 struct super_block *sb = dir->i_sb;
773 struct inode *inode;
774 struct fat_slot_info sinfo;
775 struct timespec ts;
776 int err;
777
778 mutex_lock(&MSDOS_SB(sb)->s_lock);
779
780 ts = CURRENT_TIME_SEC;
781 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);
782 if (err)
783 goto out;
784 dir->i_version++;
785
786 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
787 brelse(sinfo.bh);
788 if (IS_ERR(inode)) {
789 err = PTR_ERR(inode);
790 goto out;
791 }
792 inode->i_version++;
793 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
794 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
795
796 dentry->d_time = dentry->d_parent->d_inode->i_version;
797 d_instantiate(dentry, inode);
798out:
799 mutex_unlock(&MSDOS_SB(sb)->s_lock);
800 return err;
801}
802
803static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
804{
805 struct inode *inode = dentry->d_inode;
806 struct super_block *sb = dir->i_sb;
807 struct fat_slot_info sinfo;
808 int err;
809
810 mutex_lock(&MSDOS_SB(sb)->s_lock);
811
812 err = fat_dir_empty(inode);
813 if (err)
814 goto out;
815 err = vfat_find(dir, &dentry->d_name, &sinfo);
816 if (err)
817 goto out;
818
819 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
820 if (err)
821 goto out;
822 drop_nlink(dir);
823
824 clear_nlink(inode);
825 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
826 fat_detach(inode);
827out:
828 mutex_unlock(&MSDOS_SB(sb)->s_lock);
829
830 return err;
831}
832
833static int vfat_unlink(struct inode *dir, struct dentry *dentry)
834{
835 struct inode *inode = dentry->d_inode;
836 struct super_block *sb = dir->i_sb;
837 struct fat_slot_info sinfo;
838 int err;
839
840 mutex_lock(&MSDOS_SB(sb)->s_lock);
841
842 err = vfat_find(dir, &dentry->d_name, &sinfo);
843 if (err)
844 goto out;
845
846 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
847 if (err)
848 goto out;
849 clear_nlink(inode);
850 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
851 fat_detach(inode);
852out:
853 mutex_unlock(&MSDOS_SB(sb)->s_lock);
854
855 return err;
856}
857
858static int vfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
859{
860 struct super_block *sb = dir->i_sb;
861 struct inode *inode;
862 struct fat_slot_info sinfo;
863 struct timespec ts;
864 int err, cluster;
865
866 mutex_lock(&MSDOS_SB(sb)->s_lock);
867
868 ts = CURRENT_TIME_SEC;
869 cluster = fat_alloc_new_dir(dir, &ts);
870 if (cluster < 0) {
871 err = cluster;
872 goto out;
873 }
874 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);
875 if (err)
876 goto out_free;
877 dir->i_version++;
878 inc_nlink(dir);
879
880 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
881 brelse(sinfo.bh);
882 if (IS_ERR(inode)) {
883 err = PTR_ERR(inode);
884 /* the directory was completed, just return a error */
885 goto out;
886 }
887 inode->i_version++;
888 set_nlink(inode, 2);
889 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
890 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
891
892 dentry->d_time = dentry->d_parent->d_inode->i_version;
893 d_instantiate(dentry, inode);
894
895 mutex_unlock(&MSDOS_SB(sb)->s_lock);
896 return 0;
897
898out_free:
899 fat_free_clusters(dir, cluster);
900out:
901 mutex_unlock(&MSDOS_SB(sb)->s_lock);
902 return err;
903}
904
905static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
906 struct inode *new_dir, struct dentry *new_dentry)
907{
908 struct buffer_head *dotdot_bh;
909 struct msdos_dir_entry *dotdot_de;
910 struct inode *old_inode, *new_inode;
911 struct fat_slot_info old_sinfo, sinfo;
912 struct timespec ts;
913 loff_t new_i_pos;
914 int err, is_dir, update_dotdot, corrupt = 0;
915 struct super_block *sb = old_dir->i_sb;
916
917 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
918 old_inode = old_dentry->d_inode;
919 new_inode = new_dentry->d_inode;
920 mutex_lock(&MSDOS_SB(sb)->s_lock);
921 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);
922 if (err)
923 goto out;
924
925 is_dir = S_ISDIR(old_inode->i_mode);
926 update_dotdot = (is_dir && old_dir != new_dir);
927 if (update_dotdot) {
928 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
929 err = -EIO;
930 goto out;
931 }
932 }
933
934 ts = CURRENT_TIME_SEC;
935 if (new_inode) {
936 if (is_dir) {
937 err = fat_dir_empty(new_inode);
938 if (err)
939 goto out;
940 }
941 new_i_pos = MSDOS_I(new_inode)->i_pos;
942 fat_detach(new_inode);
943 } else {
944 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,
945 &ts, &sinfo);
946 if (err)
947 goto out;
948 new_i_pos = sinfo.i_pos;
949 }
950 new_dir->i_version++;
951
952 fat_detach(old_inode);
953 fat_attach(old_inode, new_i_pos);
954 if (IS_DIRSYNC(new_dir)) {
955 err = fat_sync_inode(old_inode);
956 if (err)
957 goto error_inode;
958 } else
959 mark_inode_dirty(old_inode);
960
961 if (update_dotdot) {
962 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
963 mark_buffer_dirty_inode(dotdot_bh, old_inode);
964 if (IS_DIRSYNC(new_dir)) {
965 err = sync_dirty_buffer(dotdot_bh);
966 if (err)
967 goto error_dotdot;
968 }
969 drop_nlink(old_dir);
970 if (!new_inode)
971 inc_nlink(new_dir);
972 }
973
974 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
975 old_sinfo.bh = NULL;
976 if (err)
977 goto error_dotdot;
978 old_dir->i_version++;
979 old_dir->i_ctime = old_dir->i_mtime = ts;
980 if (IS_DIRSYNC(old_dir))
981 (void)fat_sync_inode(old_dir);
982 else
983 mark_inode_dirty(old_dir);
984
985 if (new_inode) {
986 drop_nlink(new_inode);
987 if (is_dir)
988 drop_nlink(new_inode);
989 new_inode->i_ctime = ts;
990 }
991out:
992 brelse(sinfo.bh);
993 brelse(dotdot_bh);
994 brelse(old_sinfo.bh);
995 mutex_unlock(&MSDOS_SB(sb)->s_lock);
996
997 return err;
998
999error_dotdot:
1000 /* data cluster is shared, serious corruption */
1001 corrupt = 1;
1002
1003 if (update_dotdot) {
1004 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
1005 mark_buffer_dirty_inode(dotdot_bh, old_inode);
1006 corrupt |= sync_dirty_buffer(dotdot_bh);
1007 }
1008error_inode:
1009 fat_detach(old_inode);
1010 fat_attach(old_inode, old_sinfo.i_pos);
1011 if (new_inode) {
1012 fat_attach(new_inode, new_i_pos);
1013 if (corrupt)
1014 corrupt |= fat_sync_inode(new_inode);
1015 } else {
1016 /*
1017 * If new entry was not sharing the data cluster, it
1018 * shouldn't be serious corruption.
1019 */
1020 int err2 = fat_remove_entries(new_dir, &sinfo);
1021 if (corrupt)
1022 corrupt |= err2;
1023 sinfo.bh = NULL;
1024 }
1025 if (corrupt < 0) {
1026 fat_fs_error(new_dir->i_sb,
1027 "%s: Filesystem corrupted (i_pos %lld)",
1028 __func__, sinfo.i_pos);
1029 }
1030 goto out;
1031}
1032
1033static const struct inode_operations vfat_dir_inode_operations = {
1034 .create = vfat_create,
1035 .lookup = vfat_lookup,
1036 .unlink = vfat_unlink,
1037 .mkdir = vfat_mkdir,
1038 .rmdir = vfat_rmdir,
1039 .rename = vfat_rename,
1040 .setattr = fat_setattr,
1041 .getattr = fat_getattr,
1042};
1043
1044static void setup(struct super_block *sb)
1045{
1046 MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations;
1047 if (MSDOS_SB(sb)->options.name_check != 's')
1048 sb->s_d_op = &vfat_ci_dentry_ops;
1049 else
1050 sb->s_d_op = &vfat_dentry_ops;
1051}
1052
1053static int vfat_fill_super(struct super_block *sb, void *data, int silent)
1054{
1055 return fat_fill_super(sb, data, silent, 1, setup);
1056}
1057
1058static struct dentry *vfat_mount(struct file_system_type *fs_type,
1059 int flags, const char *dev_name,
1060 void *data)
1061{
1062 return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super);
1063}
1064
1065static struct file_system_type vfat_fs_type = {
1066 .owner = THIS_MODULE,
1067 .name = "vfat",
1068 .mount = vfat_mount,
1069 .kill_sb = kill_block_super,
1070 .fs_flags = FS_REQUIRES_DEV,
1071};
1072MODULE_ALIAS_FS("vfat");
1073
1074static int __init init_vfat_fs(void)
1075{
1076 return register_filesystem(&vfat_fs_type);
1077}
1078
1079static void __exit exit_vfat_fs(void)
1080{
1081 unregister_filesystem(&vfat_fs_type);
1082}
1083
1084MODULE_LICENSE("GPL");
1085MODULE_DESCRIPTION("VFAT filesystem support");
1086MODULE_AUTHOR("Gordon Chaffee");
1087
1088module_init(init_vfat_fs)
1089module_exit(exit_vfat_fs)
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/vfat/namei.c
4 *
5 * Written 1992,1993 by Werner Almesberger
6 *
7 * Windows95/Windows NT compatible extended MSDOS filesystem
8 * by Gordon Chaffee Copyright (C) 1995. Send bug reports for the
9 * VFAT filesystem to <chaffee@cs.berkeley.edu>. Specify
10 * what file operation caused you trouble and if you can duplicate
11 * the problem, send a script that demonstrates it.
12 *
13 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
14 *
15 * Support Multibyte characters and cleanup by
16 * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
17 */
18
19#include <linux/module.h>
20#include <linux/ctype.h>
21#include <linux/slab.h>
22#include <linux/namei.h>
23#include <linux/kernel.h>
24#include <linux/iversion.h>
25#include "fat.h"
26
27static inline unsigned long vfat_d_version(struct dentry *dentry)
28{
29 return (unsigned long) dentry->d_fsdata;
30}
31
32static inline void vfat_d_version_set(struct dentry *dentry,
33 unsigned long version)
34{
35 dentry->d_fsdata = (void *) version;
36}
37
38/*
39 * If new entry was created in the parent, it could create the 8.3
40 * alias (the shortname of logname). So, the parent may have the
41 * negative-dentry which matches the created 8.3 alias.
42 *
43 * If it happened, the negative dentry isn't actually negative
44 * anymore. So, drop it.
45 */
46static int vfat_revalidate_shortname(struct dentry *dentry)
47{
48 int ret = 1;
49 spin_lock(&dentry->d_lock);
50 if (!inode_eq_iversion(d_inode(dentry->d_parent), vfat_d_version(dentry)))
51 ret = 0;
52 spin_unlock(&dentry->d_lock);
53 return ret;
54}
55
56static int vfat_revalidate(struct dentry *dentry, unsigned int flags)
57{
58 if (flags & LOOKUP_RCU)
59 return -ECHILD;
60
61 /* This is not negative dentry. Always valid. */
62 if (d_really_is_positive(dentry))
63 return 1;
64 return vfat_revalidate_shortname(dentry);
65}
66
67static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags)
68{
69 if (flags & LOOKUP_RCU)
70 return -ECHILD;
71
72 /*
73 * This is not negative dentry. Always valid.
74 *
75 * Note, rename() to existing directory entry will have ->d_inode,
76 * and will use existing name which isn't specified name by user.
77 *
78 * We may be able to drop this positive dentry here. But dropping
79 * positive dentry isn't good idea. So it's unsupported like
80 * rename("filename", "FILENAME") for now.
81 */
82 if (d_really_is_positive(dentry))
83 return 1;
84
85 /*
86 * This may be nfsd (or something), anyway, we can't see the
87 * intent of this. So, since this can be for creation, drop it.
88 */
89 if (!flags)
90 return 0;
91
92 /*
93 * Drop the negative dentry, in order to make sure to use the
94 * case sensitive name which is specified by user if this is
95 * for creation.
96 */
97 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
98 return 0;
99
100 return vfat_revalidate_shortname(dentry);
101}
102
103/* returns the length of a struct qstr, ignoring trailing dots */
104static unsigned int __vfat_striptail_len(unsigned int len, const char *name)
105{
106 while (len && name[len - 1] == '.')
107 len--;
108 return len;
109}
110
111static unsigned int vfat_striptail_len(const struct qstr *qstr)
112{
113 return __vfat_striptail_len(qstr->len, qstr->name);
114}
115
116/*
117 * Compute the hash for the vfat name corresponding to the dentry.
118 * Note: if the name is invalid, we leave the hash code unchanged so
119 * that the existing dentry can be used. The vfat fs routines will
120 * return ENOENT or EINVAL as appropriate.
121 */
122static int vfat_hash(const struct dentry *dentry, struct qstr *qstr)
123{
124 qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr));
125 return 0;
126}
127
128/*
129 * Compute the hash for the vfat name corresponding to the dentry.
130 * Note: if the name is invalid, we leave the hash code unchanged so
131 * that the existing dentry can be used. The vfat fs routines will
132 * return ENOENT or EINVAL as appropriate.
133 */
134static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr)
135{
136 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
137 const unsigned char *name;
138 unsigned int len;
139 unsigned long hash;
140
141 name = qstr->name;
142 len = vfat_striptail_len(qstr);
143
144 hash = init_name_hash(dentry);
145 while (len--)
146 hash = partial_name_hash(nls_tolower(t, *name++), hash);
147 qstr->hash = end_name_hash(hash);
148
149 return 0;
150}
151
152/*
153 * Case insensitive compare of two vfat names.
154 */
155static int vfat_cmpi(const struct dentry *dentry,
156 unsigned int len, const char *str, const struct qstr *name)
157{
158 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
159 unsigned int alen, blen;
160
161 /* A filename cannot end in '.' or we treat it like it has none */
162 alen = vfat_striptail_len(name);
163 blen = __vfat_striptail_len(len, str);
164 if (alen == blen) {
165 if (nls_strnicmp(t, name->name, str, alen) == 0)
166 return 0;
167 }
168 return 1;
169}
170
171/*
172 * Case sensitive compare of two vfat names.
173 */
174static int vfat_cmp(const struct dentry *dentry,
175 unsigned int len, const char *str, const struct qstr *name)
176{
177 unsigned int alen, blen;
178
179 /* A filename cannot end in '.' or we treat it like it has none */
180 alen = vfat_striptail_len(name);
181 blen = __vfat_striptail_len(len, str);
182 if (alen == blen) {
183 if (strncmp(name->name, str, alen) == 0)
184 return 0;
185 }
186 return 1;
187}
188
189static const struct dentry_operations vfat_ci_dentry_ops = {
190 .d_revalidate = vfat_revalidate_ci,
191 .d_hash = vfat_hashi,
192 .d_compare = vfat_cmpi,
193};
194
195static const struct dentry_operations vfat_dentry_ops = {
196 .d_revalidate = vfat_revalidate,
197 .d_hash = vfat_hash,
198 .d_compare = vfat_cmp,
199};
200
201/* Characters that are undesirable in an MS-DOS file name */
202
203static inline wchar_t vfat_bad_char(wchar_t w)
204{
205 return (w < 0x0020)
206 || (w == '*') || (w == '?') || (w == '<') || (w == '>')
207 || (w == '|') || (w == '"') || (w == ':') || (w == '/')
208 || (w == '\\');
209}
210
211static inline wchar_t vfat_replace_char(wchar_t w)
212{
213 return (w == '[') || (w == ']') || (w == ';') || (w == ',')
214 || (w == '+') || (w == '=');
215}
216
217static wchar_t vfat_skip_char(wchar_t w)
218{
219 return (w == '.') || (w == ' ');
220}
221
222static inline int vfat_is_used_badchars(const wchar_t *s, int len)
223{
224 int i;
225
226 for (i = 0; i < len; i++)
227 if (vfat_bad_char(s[i]))
228 return -EINVAL;
229
230 if (s[i - 1] == ' ') /* last character cannot be space */
231 return -EINVAL;
232
233 return 0;
234}
235
236static int vfat_find_form(struct inode *dir, unsigned char *name)
237{
238 struct fat_slot_info sinfo;
239 int err = fat_scan(dir, name, &sinfo);
240 if (err)
241 return -ENOENT;
242 brelse(sinfo.bh);
243 return 0;
244}
245
246/*
247 * 1) Valid characters for the 8.3 format alias are any combination of
248 * letters, uppercase alphabets, digits, any of the
249 * following special characters:
250 * $ % ' ` - @ { } ~ ! # ( ) & _ ^
251 * In this case Longfilename is not stored in disk.
252 *
253 * WinNT's Extension:
254 * File name and extension name is contain uppercase/lowercase
255 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
256 *
257 * 2) File name is 8.3 format, but it contain the uppercase and
258 * lowercase char, muliti bytes char, etc. In this case numtail is not
259 * added, but Longfilename is stored.
260 *
261 * 3) When the one except for the above, or the following special
262 * character are contained:
263 * . [ ] ; , + =
264 * numtail is added, and Longfilename must be stored in disk .
265 */
266struct shortname_info {
267 unsigned char lower:1,
268 upper:1,
269 valid:1;
270};
271#define INIT_SHORTNAME_INFO(x) do { \
272 (x)->lower = 1; \
273 (x)->upper = 1; \
274 (x)->valid = 1; \
275} while (0)
276
277static inline int to_shortname_char(struct nls_table *nls,
278 unsigned char *buf, int buf_size,
279 wchar_t *src, struct shortname_info *info)
280{
281 int len;
282
283 if (vfat_skip_char(*src)) {
284 info->valid = 0;
285 return 0;
286 }
287 if (vfat_replace_char(*src)) {
288 info->valid = 0;
289 buf[0] = '_';
290 return 1;
291 }
292
293 len = nls->uni2char(*src, buf, buf_size);
294 if (len <= 0) {
295 info->valid = 0;
296 buf[0] = '_';
297 len = 1;
298 } else if (len == 1) {
299 unsigned char prev = buf[0];
300
301 if (buf[0] >= 0x7F) {
302 info->lower = 0;
303 info->upper = 0;
304 }
305
306 buf[0] = nls_toupper(nls, buf[0]);
307 if (isalpha(buf[0])) {
308 if (buf[0] == prev)
309 info->lower = 0;
310 else
311 info->upper = 0;
312 }
313 } else {
314 info->lower = 0;
315 info->upper = 0;
316 }
317
318 return len;
319}
320
321/*
322 * Given a valid longname, create a unique shortname. Make sure the
323 * shortname does not exist
324 * Returns negative number on error, 0 for a normal
325 * return, and 1 for valid shortname
326 */
327static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
328 wchar_t *uname, int ulen,
329 unsigned char *name_res, unsigned char *lcase)
330{
331 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;
332 wchar_t *ip, *ext_start, *end, *name_start;
333 unsigned char base[9], ext[4], buf[5], *p;
334 unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
335 int chl, chi;
336 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
337 int is_shortname;
338 struct shortname_info base_info, ext_info;
339
340 is_shortname = 1;
341 INIT_SHORTNAME_INFO(&base_info);
342 INIT_SHORTNAME_INFO(&ext_info);
343
344 /* Now, we need to create a shortname from the long name */
345 ext_start = end = &uname[ulen];
346 while (--ext_start >= uname) {
347 if (*ext_start == 0x002E) { /* is `.' */
348 if (ext_start == end - 1) {
349 sz = ulen;
350 ext_start = NULL;
351 }
352 break;
353 }
354 }
355
356 if (ext_start == uname - 1) {
357 sz = ulen;
358 ext_start = NULL;
359 } else if (ext_start) {
360 /*
361 * Names which start with a dot could be just
362 * an extension eg. "...test". In this case Win95
363 * uses the extension as the name and sets no extension.
364 */
365 name_start = &uname[0];
366 while (name_start < ext_start) {
367 if (!vfat_skip_char(*name_start))
368 break;
369 name_start++;
370 }
371 if (name_start != ext_start) {
372 sz = ext_start - uname;
373 ext_start++;
374 } else {
375 sz = ulen;
376 ext_start = NULL;
377 }
378 }
379
380 numtail_baselen = 6;
381 numtail2_baselen = 2;
382 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
383 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
384 ip, &base_info);
385 if (chl == 0)
386 continue;
387
388 if (baselen < 2 && (baselen + chl) > 2)
389 numtail2_baselen = baselen;
390 if (baselen < 6 && (baselen + chl) > 6)
391 numtail_baselen = baselen;
392 for (chi = 0; chi < chl; chi++) {
393 *p++ = charbuf[chi];
394 baselen++;
395 if (baselen >= 8)
396 break;
397 }
398 if (baselen >= 8) {
399 if ((chi < chl - 1) || (ip + 1) - uname < sz)
400 is_shortname = 0;
401 break;
402 }
403 }
404 if (baselen == 0) {
405 return -EINVAL;
406 }
407
408 extlen = 0;
409 if (ext_start) {
410 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
411 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
412 ip, &ext_info);
413 if (chl == 0)
414 continue;
415
416 if ((extlen + chl) > 3) {
417 is_shortname = 0;
418 break;
419 }
420 for (chi = 0; chi < chl; chi++) {
421 *p++ = charbuf[chi];
422 extlen++;
423 }
424 if (extlen >= 3) {
425 if (ip + 1 != end)
426 is_shortname = 0;
427 break;
428 }
429 }
430 }
431 ext[extlen] = '\0';
432 base[baselen] = '\0';
433
434 /* Yes, it can happen. ".\xe5" would do it. */
435 if (base[0] == DELETED_FLAG)
436 base[0] = 0x05;
437
438 /* OK, at this point we know that base is not longer than 8 symbols,
439 * ext is not longer than 3, base is nonempty, both don't contain
440 * any bad symbols (lowercase transformed to uppercase).
441 */
442
443 memset(name_res, ' ', MSDOS_NAME);
444 memcpy(name_res, base, baselen);
445 memcpy(name_res + 8, ext, extlen);
446 *lcase = 0;
447 if (is_shortname && base_info.valid && ext_info.valid) {
448 if (vfat_find_form(dir, name_res) == 0)
449 return -EEXIST;
450
451 if (opts->shortname & VFAT_SFN_CREATE_WIN95) {
452 return (base_info.upper && ext_info.upper);
453 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {
454 if ((base_info.upper || base_info.lower) &&
455 (ext_info.upper || ext_info.lower)) {
456 if (!base_info.upper && base_info.lower)
457 *lcase |= CASE_LOWER_BASE;
458 if (!ext_info.upper && ext_info.lower)
459 *lcase |= CASE_LOWER_EXT;
460 return 1;
461 }
462 return 0;
463 } else {
464 BUG();
465 }
466 }
467
468 if (opts->numtail == 0)
469 if (vfat_find_form(dir, name_res) < 0)
470 return 0;
471
472 /*
473 * Try to find a unique extension. This used to
474 * iterate through all possibilities sequentially,
475 * but that gave extremely bad performance. Windows
476 * only tries a few cases before using random
477 * values for part of the base.
478 */
479
480 if (baselen > 6) {
481 baselen = numtail_baselen;
482 name_res[7] = ' ';
483 }
484 name_res[baselen] = '~';
485 for (i = 1; i < 10; i++) {
486 name_res[baselen + 1] = i + '0';
487 if (vfat_find_form(dir, name_res) < 0)
488 return 0;
489 }
490
491 i = jiffies;
492 sz = (jiffies >> 16) & 0x7;
493 if (baselen > 2) {
494 baselen = numtail2_baselen;
495 name_res[7] = ' ';
496 }
497 name_res[baselen + 4] = '~';
498 name_res[baselen + 5] = '1' + sz;
499 while (1) {
500 snprintf(buf, sizeof(buf), "%04X", i & 0xffff);
501 memcpy(&name_res[baselen], buf, 4);
502 if (vfat_find_form(dir, name_res) < 0)
503 break;
504 i -= 11;
505 }
506 return 0;
507}
508
509/* Translate a string, including coded sequences into Unicode */
510static int
511xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
512 int *longlen, int *outlen, int escape, int utf8,
513 struct nls_table *nls)
514{
515 const unsigned char *ip;
516 unsigned char *op;
517 int i, fill;
518 int charlen;
519
520 if (utf8) {
521 *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN,
522 (wchar_t *) outname, FAT_LFN_LEN + 2);
523 if (*outlen < 0)
524 return *outlen;
525 else if (*outlen > FAT_LFN_LEN)
526 return -ENAMETOOLONG;
527
528 op = &outname[*outlen * sizeof(wchar_t)];
529 } else {
530 for (i = 0, ip = name, op = outname, *outlen = 0;
531 i < len && *outlen < FAT_LFN_LEN;
532 *outlen += 1) {
533 if (escape && (*ip == ':')) {
534 u8 uc[2];
535
536 if (i > len - 5)
537 return -EINVAL;
538
539 if (hex2bin(uc, ip + 1, 2) < 0)
540 return -EINVAL;
541
542 *(wchar_t *)op = uc[0] << 8 | uc[1];
543
544 op += 2;
545 ip += 5;
546 i += 5;
547 } else {
548 charlen = nls->char2uni(ip, len - i,
549 (wchar_t *)op);
550 if (charlen < 0)
551 return -EINVAL;
552 ip += charlen;
553 i += charlen;
554 op += 2;
555 }
556 }
557 if (i < len)
558 return -ENAMETOOLONG;
559 }
560
561 *longlen = *outlen;
562 if (*outlen % 13) {
563 *op++ = 0;
564 *op++ = 0;
565 *outlen += 1;
566 if (*outlen % 13) {
567 fill = 13 - (*outlen % 13);
568 for (i = 0; i < fill; i++) {
569 *op++ = 0xff;
570 *op++ = 0xff;
571 }
572 *outlen += fill;
573 }
574 }
575
576 return 0;
577}
578
579static int vfat_build_slots(struct inode *dir, const unsigned char *name,
580 int len, int is_dir, int cluster,
581 struct timespec64 *ts,
582 struct msdos_dir_slot *slots, int *nr_slots)
583{
584 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
585 struct fat_mount_options *opts = &sbi->options;
586 struct msdos_dir_slot *ps;
587 struct msdos_dir_entry *de;
588 unsigned char cksum, lcase;
589 unsigned char msdos_name[MSDOS_NAME];
590 wchar_t *uname;
591 __le16 time, date;
592 u8 time_cs;
593 int err, ulen, usize, i;
594 loff_t offset;
595
596 *nr_slots = 0;
597
598 uname = __getname();
599 if (!uname)
600 return -ENOMEM;
601
602 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
603 opts->unicode_xlate, opts->utf8, sbi->nls_io);
604 if (err)
605 goto out_free;
606
607 err = vfat_is_used_badchars(uname, ulen);
608 if (err)
609 goto out_free;
610
611 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
612 msdos_name, &lcase);
613 if (err < 0)
614 goto out_free;
615 else if (err == 1) {
616 de = (struct msdos_dir_entry *)slots;
617 err = 0;
618 goto shortname;
619 }
620
621 /* build the entry of long file name */
622 cksum = fat_checksum(msdos_name);
623
624 *nr_slots = usize / 13;
625 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {
626 ps->id = i;
627 ps->attr = ATTR_EXT;
628 ps->reserved = 0;
629 ps->alias_checksum = cksum;
630 ps->start = 0;
631 offset = (i - 1) * 13;
632 fatwchar_to16(ps->name0_4, uname + offset, 5);
633 fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
634 fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
635 }
636 slots[0].id |= 0x40;
637 de = (struct msdos_dir_entry *)ps;
638
639shortname:
640 /* build the entry of 8.3 alias name */
641 (*nr_slots)++;
642 memcpy(de->name, msdos_name, MSDOS_NAME);
643 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
644 de->lcase = lcase;
645 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
646 de->time = de->ctime = time;
647 de->date = de->cdate = de->adate = date;
648 de->ctime_cs = time_cs;
649 fat_set_start(de, cluster);
650 de->size = 0;
651out_free:
652 __putname(uname);
653 return err;
654}
655
656static int vfat_add_entry(struct inode *dir, const struct qstr *qname,
657 int is_dir, int cluster, struct timespec64 *ts,
658 struct fat_slot_info *sinfo)
659{
660 struct msdos_dir_slot *slots;
661 unsigned int len;
662 int err, nr_slots;
663
664 len = vfat_striptail_len(qname);
665 if (len == 0)
666 return -ENOENT;
667
668 slots = kmalloc_array(MSDOS_SLOTS, sizeof(*slots), GFP_NOFS);
669 if (slots == NULL)
670 return -ENOMEM;
671
672 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,
673 slots, &nr_slots);
674 if (err)
675 goto cleanup;
676
677 err = fat_add_entries(dir, slots, nr_slots, sinfo);
678 if (err)
679 goto cleanup;
680
681 /* update timestamp */
682 fat_truncate_time(dir, ts, S_CTIME|S_MTIME);
683 if (IS_DIRSYNC(dir))
684 (void)fat_sync_inode(dir);
685 else
686 mark_inode_dirty(dir);
687cleanup:
688 kfree(slots);
689 return err;
690}
691
692static int vfat_find(struct inode *dir, const struct qstr *qname,
693 struct fat_slot_info *sinfo)
694{
695 unsigned int len = vfat_striptail_len(qname);
696 if (len == 0)
697 return -ENOENT;
698 return fat_search_long(dir, qname->name, len, sinfo);
699}
700
701static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
702 unsigned int flags)
703{
704 struct super_block *sb = dir->i_sb;
705 struct fat_slot_info sinfo;
706 struct inode *inode;
707 struct dentry *alias;
708 int err;
709
710 mutex_lock(&MSDOS_SB(sb)->s_lock);
711
712 err = vfat_find(dir, &dentry->d_name, &sinfo);
713 if (err) {
714 if (err == -ENOENT) {
715 inode = NULL;
716 goto out;
717 }
718 goto error;
719 }
720
721 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
722 brelse(sinfo.bh);
723 if (IS_ERR(inode)) {
724 err = PTR_ERR(inode);
725 goto error;
726 }
727
728 alias = d_find_alias(inode);
729 /*
730 * Checking "alias->d_parent == dentry->d_parent" to make sure
731 * FS is not corrupted (especially double linked dir).
732 */
733 if (alias && alias->d_parent == dentry->d_parent) {
734 /*
735 * This inode has non anonymous-DCACHE_DISCONNECTED
736 * dentry. This means, the user did ->lookup() by an
737 * another name (longname vs 8.3 alias of it) in past.
738 *
739 * Switch to new one for reason of locality if possible.
740 */
741 if (!S_ISDIR(inode->i_mode))
742 d_move(alias, dentry);
743 iput(inode);
744 mutex_unlock(&MSDOS_SB(sb)->s_lock);
745 return alias;
746 } else
747 dput(alias);
748
749out:
750 mutex_unlock(&MSDOS_SB(sb)->s_lock);
751 if (!inode)
752 vfat_d_version_set(dentry, inode_query_iversion(dir));
753 return d_splice_alias(inode, dentry);
754error:
755 mutex_unlock(&MSDOS_SB(sb)->s_lock);
756 return ERR_PTR(err);
757}
758
759static int vfat_create(struct inode *dir, struct dentry *dentry, umode_t mode,
760 bool excl)
761{
762 struct super_block *sb = dir->i_sb;
763 struct inode *inode;
764 struct fat_slot_info sinfo;
765 struct timespec64 ts;
766 int err;
767
768 mutex_lock(&MSDOS_SB(sb)->s_lock);
769
770 ts = current_time(dir);
771 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);
772 if (err)
773 goto out;
774 inode_inc_iversion(dir);
775
776 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
777 brelse(sinfo.bh);
778 if (IS_ERR(inode)) {
779 err = PTR_ERR(inode);
780 goto out;
781 }
782 inode_inc_iversion(inode);
783 fat_truncate_time(inode, &ts, S_ATIME|S_CTIME|S_MTIME);
784 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
785
786 d_instantiate(dentry, inode);
787out:
788 mutex_unlock(&MSDOS_SB(sb)->s_lock);
789 return err;
790}
791
792static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
793{
794 struct inode *inode = d_inode(dentry);
795 struct super_block *sb = dir->i_sb;
796 struct fat_slot_info sinfo;
797 int err;
798
799 mutex_lock(&MSDOS_SB(sb)->s_lock);
800
801 err = fat_dir_empty(inode);
802 if (err)
803 goto out;
804 err = vfat_find(dir, &dentry->d_name, &sinfo);
805 if (err)
806 goto out;
807
808 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
809 if (err)
810 goto out;
811 drop_nlink(dir);
812
813 clear_nlink(inode);
814 fat_truncate_time(inode, NULL, S_ATIME|S_MTIME);
815 fat_detach(inode);
816 vfat_d_version_set(dentry, inode_query_iversion(dir));
817out:
818 mutex_unlock(&MSDOS_SB(sb)->s_lock);
819
820 return err;
821}
822
823static int vfat_unlink(struct inode *dir, struct dentry *dentry)
824{
825 struct inode *inode = d_inode(dentry);
826 struct super_block *sb = dir->i_sb;
827 struct fat_slot_info sinfo;
828 int err;
829
830 mutex_lock(&MSDOS_SB(sb)->s_lock);
831
832 err = vfat_find(dir, &dentry->d_name, &sinfo);
833 if (err)
834 goto out;
835
836 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
837 if (err)
838 goto out;
839 clear_nlink(inode);
840 fat_truncate_time(inode, NULL, S_ATIME|S_MTIME);
841 fat_detach(inode);
842 vfat_d_version_set(dentry, inode_query_iversion(dir));
843out:
844 mutex_unlock(&MSDOS_SB(sb)->s_lock);
845
846 return err;
847}
848
849static int vfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
850{
851 struct super_block *sb = dir->i_sb;
852 struct inode *inode;
853 struct fat_slot_info sinfo;
854 struct timespec64 ts;
855 int err, cluster;
856
857 mutex_lock(&MSDOS_SB(sb)->s_lock);
858
859 ts = current_time(dir);
860 cluster = fat_alloc_new_dir(dir, &ts);
861 if (cluster < 0) {
862 err = cluster;
863 goto out;
864 }
865 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);
866 if (err)
867 goto out_free;
868 inode_inc_iversion(dir);
869 inc_nlink(dir);
870
871 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
872 brelse(sinfo.bh);
873 if (IS_ERR(inode)) {
874 err = PTR_ERR(inode);
875 /* the directory was completed, just return a error */
876 goto out;
877 }
878 inode_inc_iversion(inode);
879 set_nlink(inode, 2);
880 fat_truncate_time(inode, &ts, S_ATIME|S_CTIME|S_MTIME);
881 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
882
883 d_instantiate(dentry, inode);
884
885 mutex_unlock(&MSDOS_SB(sb)->s_lock);
886 return 0;
887
888out_free:
889 fat_free_clusters(dir, cluster);
890out:
891 mutex_unlock(&MSDOS_SB(sb)->s_lock);
892 return err;
893}
894
895static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
896 struct inode *new_dir, struct dentry *new_dentry,
897 unsigned int flags)
898{
899 struct buffer_head *dotdot_bh;
900 struct msdos_dir_entry *dotdot_de;
901 struct inode *old_inode, *new_inode;
902 struct fat_slot_info old_sinfo, sinfo;
903 struct timespec64 ts;
904 loff_t new_i_pos;
905 int err, is_dir, update_dotdot, corrupt = 0;
906 struct super_block *sb = old_dir->i_sb;
907
908 if (flags & ~RENAME_NOREPLACE)
909 return -EINVAL;
910
911 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
912 old_inode = d_inode(old_dentry);
913 new_inode = d_inode(new_dentry);
914 mutex_lock(&MSDOS_SB(sb)->s_lock);
915 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);
916 if (err)
917 goto out;
918
919 is_dir = S_ISDIR(old_inode->i_mode);
920 update_dotdot = (is_dir && old_dir != new_dir);
921 if (update_dotdot) {
922 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
923 err = -EIO;
924 goto out;
925 }
926 }
927
928 ts = current_time(old_dir);
929 if (new_inode) {
930 if (is_dir) {
931 err = fat_dir_empty(new_inode);
932 if (err)
933 goto out;
934 }
935 new_i_pos = MSDOS_I(new_inode)->i_pos;
936 fat_detach(new_inode);
937 } else {
938 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,
939 &ts, &sinfo);
940 if (err)
941 goto out;
942 new_i_pos = sinfo.i_pos;
943 }
944 inode_inc_iversion(new_dir);
945
946 fat_detach(old_inode);
947 fat_attach(old_inode, new_i_pos);
948 if (IS_DIRSYNC(new_dir)) {
949 err = fat_sync_inode(old_inode);
950 if (err)
951 goto error_inode;
952 } else
953 mark_inode_dirty(old_inode);
954
955 if (update_dotdot) {
956 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
957 mark_buffer_dirty_inode(dotdot_bh, old_inode);
958 if (IS_DIRSYNC(new_dir)) {
959 err = sync_dirty_buffer(dotdot_bh);
960 if (err)
961 goto error_dotdot;
962 }
963 drop_nlink(old_dir);
964 if (!new_inode)
965 inc_nlink(new_dir);
966 }
967
968 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
969 old_sinfo.bh = NULL;
970 if (err)
971 goto error_dotdot;
972 inode_inc_iversion(old_dir);
973 fat_truncate_time(old_dir, &ts, S_CTIME|S_MTIME);
974 if (IS_DIRSYNC(old_dir))
975 (void)fat_sync_inode(old_dir);
976 else
977 mark_inode_dirty(old_dir);
978
979 if (new_inode) {
980 drop_nlink(new_inode);
981 if (is_dir)
982 drop_nlink(new_inode);
983 fat_truncate_time(new_inode, &ts, S_CTIME);
984 }
985out:
986 brelse(sinfo.bh);
987 brelse(dotdot_bh);
988 brelse(old_sinfo.bh);
989 mutex_unlock(&MSDOS_SB(sb)->s_lock);
990
991 return err;
992
993error_dotdot:
994 /* data cluster is shared, serious corruption */
995 corrupt = 1;
996
997 if (update_dotdot) {
998 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
999 mark_buffer_dirty_inode(dotdot_bh, old_inode);
1000 corrupt |= sync_dirty_buffer(dotdot_bh);
1001 }
1002error_inode:
1003 fat_detach(old_inode);
1004 fat_attach(old_inode, old_sinfo.i_pos);
1005 if (new_inode) {
1006 fat_attach(new_inode, new_i_pos);
1007 if (corrupt)
1008 corrupt |= fat_sync_inode(new_inode);
1009 } else {
1010 /*
1011 * If new entry was not sharing the data cluster, it
1012 * shouldn't be serious corruption.
1013 */
1014 int err2 = fat_remove_entries(new_dir, &sinfo);
1015 if (corrupt)
1016 corrupt |= err2;
1017 sinfo.bh = NULL;
1018 }
1019 if (corrupt < 0) {
1020 fat_fs_error(new_dir->i_sb,
1021 "%s: Filesystem corrupted (i_pos %lld)",
1022 __func__, sinfo.i_pos);
1023 }
1024 goto out;
1025}
1026
1027static const struct inode_operations vfat_dir_inode_operations = {
1028 .create = vfat_create,
1029 .lookup = vfat_lookup,
1030 .unlink = vfat_unlink,
1031 .mkdir = vfat_mkdir,
1032 .rmdir = vfat_rmdir,
1033 .rename = vfat_rename,
1034 .setattr = fat_setattr,
1035 .getattr = fat_getattr,
1036 .update_time = fat_update_time,
1037};
1038
1039static void setup(struct super_block *sb)
1040{
1041 MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations;
1042 if (MSDOS_SB(sb)->options.name_check != 's')
1043 sb->s_d_op = &vfat_ci_dentry_ops;
1044 else
1045 sb->s_d_op = &vfat_dentry_ops;
1046}
1047
1048static int vfat_fill_super(struct super_block *sb, void *data, int silent)
1049{
1050 return fat_fill_super(sb, data, silent, 1, setup);
1051}
1052
1053static struct dentry *vfat_mount(struct file_system_type *fs_type,
1054 int flags, const char *dev_name,
1055 void *data)
1056{
1057 return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super);
1058}
1059
1060static struct file_system_type vfat_fs_type = {
1061 .owner = THIS_MODULE,
1062 .name = "vfat",
1063 .mount = vfat_mount,
1064 .kill_sb = kill_block_super,
1065 .fs_flags = FS_REQUIRES_DEV,
1066};
1067MODULE_ALIAS_FS("vfat");
1068
1069static int __init init_vfat_fs(void)
1070{
1071 return register_filesystem(&vfat_fs_type);
1072}
1073
1074static void __exit exit_vfat_fs(void)
1075{
1076 unregister_filesystem(&vfat_fs_type);
1077}
1078
1079MODULE_LICENSE("GPL");
1080MODULE_DESCRIPTION("VFAT filesystem support");
1081MODULE_AUTHOR("Gordon Chaffee");
1082
1083module_init(init_vfat_fs)
1084module_exit(exit_vfat_fs)