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1 /*
2 * fat.c
3 *
4 * R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
5 *
6 * 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
7 * 2003-03-10 - kharris@nexus-tech.net - ported to uboot
8 *
9 * SPDX-License-Identifier: GPL-2.0+
10 */
11
12 #include <common.h>
13 #include <blk.h>
14 #include <config.h>
15 #include <exports.h>
16 #include <fat.h>
17 #include <fs.h>
18 #include <asm/byteorder.h>
19 #include <part.h>
20 #include <malloc.h>
21 #include <memalign.h>
22 #include <linux/compiler.h>
23 #include <linux/ctype.h>
24
25 #ifdef CONFIG_SUPPORT_VFAT
26 static const int vfat_enabled = 1;
27 #else
28 static const int vfat_enabled = 0;
29 #endif
30
31 /*
32 * Convert a string to lowercase. Converts at most 'len' characters,
33 * 'len' may be larger than the length of 'str' if 'str' is NULL
34 * terminated.
35 */
36 static void downcase(char *str, size_t len)
37 {
38 while (*str != '\0' && len--) {
39 *str = tolower(*str);
40 str++;
41 }
42 }
43
44 static struct blk_desc *cur_dev;
45 static disk_partition_t cur_part_info;
46
47 #define DOS_BOOT_MAGIC_OFFSET 0x1fe
48 #define DOS_FS_TYPE_OFFSET 0x36
49 #define DOS_FS32_TYPE_OFFSET 0x52
50
51 static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
52 {
53 ulong ret;
54
55 if (!cur_dev)
56 return -1;
57
58 ret = blk_dread(cur_dev, cur_part_info.start + block, nr_blocks, buf);
59
60 if (ret != nr_blocks)
61 return -1;
62
63 return ret;
64 }
65
66 int fat_set_blk_dev(struct blk_desc *dev_desc, disk_partition_t *info)
67 {
68 ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
69
70 cur_dev = dev_desc;
71 cur_part_info = *info;
72
73 /* Make sure it has a valid FAT header */
74 if (disk_read(0, 1, buffer) != 1) {
75 cur_dev = NULL;
76 return -1;
77 }
78
79 /* Check if it's actually a DOS volume */
80 if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
81 cur_dev = NULL;
82 return -1;
83 }
84
85 /* Check for FAT12/FAT16/FAT32 filesystem */
86 if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
87 return 0;
88 if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
89 return 0;
90
91 cur_dev = NULL;
92 return -1;
93 }
94
95 int fat_register_device(struct blk_desc *dev_desc, int part_no)
96 {
97 disk_partition_t info;
98
99 /* First close any currently found FAT filesystem */
100 cur_dev = NULL;
101
102 /* Read the partition table, if present */
103 if (part_get_info(dev_desc, part_no, &info)) {
104 if (part_no != 0) {
105 printf("** Partition %d not valid on device %d **\n",
106 part_no, dev_desc->devnum);
107 return -1;
108 }
109
110 info.start = 0;
111 info.size = dev_desc->lba;
112 info.blksz = dev_desc->blksz;
113 info.name[0] = 0;
114 info.type[0] = 0;
115 info.bootable = 0;
116 #if CONFIG_IS_ENABLED(PARTITION_UUIDS)
117 info.uuid[0] = 0;
118 #endif
119 }
120
121 return fat_set_blk_dev(dev_desc, &info);
122 }
123
124 /*
125 * Extract zero terminated short name from a directory entry.
126 */
127 static void get_name(dir_entry *dirent, char *s_name)
128 {
129 char *ptr;
130
131 memcpy(s_name, dirent->name, 8);
132 s_name[8] = '\0';
133 ptr = s_name;
134 while (*ptr && *ptr != ' ')
135 ptr++;
136 if (dirent->lcase & CASE_LOWER_BASE)
137 downcase(s_name, (unsigned)(ptr - s_name));
138 if (dirent->ext[0] && dirent->ext[0] != ' ') {
139 *ptr++ = '.';
140 memcpy(ptr, dirent->ext, 3);
141 if (dirent->lcase & CASE_LOWER_EXT)
142 downcase(ptr, 3);
143 ptr[3] = '\0';
144 while (*ptr && *ptr != ' ')
145 ptr++;
146 }
147 *ptr = '\0';
148 if (*s_name == DELETED_FLAG)
149 *s_name = '\0';
150 else if (*s_name == aRING)
151 *s_name = DELETED_FLAG;
152 }
153
154 static int flush_dirty_fat_buffer(fsdata *mydata);
155 #if !defined(CONFIG_FAT_WRITE)
156 /* Stub for read only operation */
157 int flush_dirty_fat_buffer(fsdata *mydata)
158 {
159 (void)(mydata);
160 return 0;
161 }
162 #endif
163
164 /*
165 * Get the entry at index 'entry' in a FAT (12/16/32) table.
166 * On failure 0x00 is returned.
167 */
168 static __u32 get_fatent(fsdata *mydata, __u32 entry)
169 {
170 __u32 bufnum;
171 __u32 offset, off8;
172 __u32 ret = 0x00;
173
174 if (CHECK_CLUST(entry, mydata->fatsize)) {
175 printf("Error: Invalid FAT entry: 0x%08x\n", entry);
176 return ret;
177 }
178
179 switch (mydata->fatsize) {
180 case 32:
181 bufnum = entry / FAT32BUFSIZE;
182 offset = entry - bufnum * FAT32BUFSIZE;
183 break;
184 case 16:
185 bufnum = entry / FAT16BUFSIZE;
186 offset = entry - bufnum * FAT16BUFSIZE;
187 break;
188 case 12:
189 bufnum = entry / FAT12BUFSIZE;
190 offset = entry - bufnum * FAT12BUFSIZE;
191 break;
192
193 default:
194 /* Unsupported FAT size */
195 return ret;
196 }
197
198 debug("FAT%d: entry: 0x%08x = %d, offset: 0x%04x = %d\n",
199 mydata->fatsize, entry, entry, offset, offset);
200
201 /* Read a new block of FAT entries into the cache. */
202 if (bufnum != mydata->fatbufnum) {
203 __u32 getsize = FATBUFBLOCKS;
204 __u8 *bufptr = mydata->fatbuf;
205 __u32 fatlength = mydata->fatlength;
206 __u32 startblock = bufnum * FATBUFBLOCKS;
207
208 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
209 if (startblock + getsize > fatlength)
210 getsize = fatlength - startblock;
211
212 startblock += mydata->fat_sect; /* Offset from start of disk */
213
214 /* Write back the fatbuf to the disk */
215 if (flush_dirty_fat_buffer(mydata) < 0)
216 return -1;
217
218 if (disk_read(startblock, getsize, bufptr) < 0) {
219 debug("Error reading FAT blocks\n");
220 return ret;
221 }
222 mydata->fatbufnum = bufnum;
223 }
224
225 /* Get the actual entry from the table */
226 switch (mydata->fatsize) {
227 case 32:
228 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
229 break;
230 case 16:
231 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
232 break;
233 case 12:
234 off8 = (offset * 3) / 2;
235 /* fatbut + off8 may be unaligned, read in byte granularity */
236 ret = mydata->fatbuf[off8] + (mydata->fatbuf[off8 + 1] << 8);
237
238 if (offset & 0x1)
239 ret >>= 4;
240 ret &= 0xfff;
241 }
242 debug("FAT%d: ret: 0x%08x, entry: 0x%08x, offset: 0x%04x\n",
243 mydata->fatsize, ret, entry, offset);
244
245 return ret;
246 }
247
248 /*
249 * Read at most 'size' bytes from the specified cluster into 'buffer'.
250 * Return 0 on success, -1 otherwise.
251 */
252 static int
253 get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
254 {
255 __u32 idx = 0;
256 __u32 startsect;
257 int ret;
258
259 if (clustnum > 0) {
260 startsect = clust_to_sect(mydata, clustnum);
261 } else {
262 startsect = mydata->rootdir_sect;
263 }
264
265 debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
266
267 if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
268 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
269
270 printf("FAT: Misaligned buffer address (%p)\n", buffer);
271
272 while (size >= mydata->sect_size) {
273 ret = disk_read(startsect++, 1, tmpbuf);
274 if (ret != 1) {
275 debug("Error reading data (got %d)\n", ret);
276 return -1;
277 }
278
279 memcpy(buffer, tmpbuf, mydata->sect_size);
280 buffer += mydata->sect_size;
281 size -= mydata->sect_size;
282 }
283 } else {
284 idx = size / mydata->sect_size;
285 ret = disk_read(startsect, idx, buffer);
286 if (ret != idx) {
287 debug("Error reading data (got %d)\n", ret);
288 return -1;
289 }
290 startsect += idx;
291 idx *= mydata->sect_size;
292 buffer += idx;
293 size -= idx;
294 }
295 if (size) {
296 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
297
298 ret = disk_read(startsect, 1, tmpbuf);
299 if (ret != 1) {
300 debug("Error reading data (got %d)\n", ret);
301 return -1;
302 }
303
304 memcpy(buffer, tmpbuf, size);
305 }
306
307 return 0;
308 }
309
310 /*
311 * Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
312 * into 'buffer'.
313 * Update the number of bytes read in *gotsize or return -1 on fatal errors.
314 */
315 __u8 get_contents_vfatname_block[MAX_CLUSTSIZE]
316 __aligned(ARCH_DMA_MINALIGN);
317
318 static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
319 __u8 *buffer, loff_t maxsize, loff_t *gotsize)
320 {
321 loff_t filesize = FAT2CPU32(dentptr->size);
322 unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
323 __u32 curclust = START(dentptr);
324 __u32 endclust, newclust;
325 loff_t actsize;
326
327 *gotsize = 0;
328 debug("Filesize: %llu bytes\n", filesize);
329
330 if (pos >= filesize) {
331 debug("Read position past EOF: %llu\n", pos);
332 return 0;
333 }
334
335 if (maxsize > 0 && filesize > pos + maxsize)
336 filesize = pos + maxsize;
337
338 debug("%llu bytes\n", filesize);
339
340 actsize = bytesperclust;
341
342 /* go to cluster at pos */
343 while (actsize <= pos) {
344 curclust = get_fatent(mydata, curclust);
345 if (CHECK_CLUST(curclust, mydata->fatsize)) {
346 debug("curclust: 0x%x\n", curclust);
347 debug("Invalid FAT entry\n");
348 return 0;
349 }
350 actsize += bytesperclust;
351 }
352
353 /* actsize > pos */
354 actsize -= bytesperclust;
355 filesize -= actsize;
356 pos -= actsize;
357
358 /* align to beginning of next cluster if any */
359 if (pos) {
360 actsize = min(filesize, (loff_t)bytesperclust);
361 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
362 (int)actsize) != 0) {
363 printf("Error reading cluster\n");
364 return -1;
365 }
366 filesize -= actsize;
367 actsize -= pos;
368 memcpy(buffer, get_contents_vfatname_block + pos, actsize);
369 *gotsize += actsize;
370 if (!filesize)
371 return 0;
372 buffer += actsize;
373
374 curclust = get_fatent(mydata, curclust);
375 if (CHECK_CLUST(curclust, mydata->fatsize)) {
376 debug("curclust: 0x%x\n", curclust);
377 debug("Invalid FAT entry\n");
378 return 0;
379 }
380 }
381
382 actsize = bytesperclust;
383 endclust = curclust;
384
385 do {
386 /* search for consecutive clusters */
387 while (actsize < filesize) {
388 newclust = get_fatent(mydata, endclust);
389 if ((newclust - 1) != endclust)
390 goto getit;
391 if (CHECK_CLUST(newclust, mydata->fatsize)) {
392 debug("curclust: 0x%x\n", newclust);
393 debug("Invalid FAT entry\n");
394 return 0;
395 }
396 endclust = newclust;
397 actsize += bytesperclust;
398 }
399
400 /* get remaining bytes */
401 actsize = filesize;
402 if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
403 printf("Error reading cluster\n");
404 return -1;
405 }
406 *gotsize += actsize;
407 return 0;
408 getit:
409 if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
410 printf("Error reading cluster\n");
411 return -1;
412 }
413 *gotsize += (int)actsize;
414 filesize -= actsize;
415 buffer += actsize;
416
417 curclust = get_fatent(mydata, endclust);
418 if (CHECK_CLUST(curclust, mydata->fatsize)) {
419 debug("curclust: 0x%x\n", curclust);
420 printf("Invalid FAT entry\n");
421 return 0;
422 }
423 actsize = bytesperclust;
424 endclust = curclust;
425 } while (1);
426 }
427
428 /*
429 * Extract the file name information from 'slotptr' into 'l_name',
430 * starting at l_name[*idx].
431 * Return 1 if terminator (zero byte) is found, 0 otherwise.
432 */
433 static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
434 {
435 int j;
436
437 for (j = 0; j <= 8; j += 2) {
438 l_name[*idx] = slotptr->name0_4[j];
439 if (l_name[*idx] == 0x00)
440 return 1;
441 (*idx)++;
442 }
443 for (j = 0; j <= 10; j += 2) {
444 l_name[*idx] = slotptr->name5_10[j];
445 if (l_name[*idx] == 0x00)
446 return 1;
447 (*idx)++;
448 }
449 for (j = 0; j <= 2; j += 2) {
450 l_name[*idx] = slotptr->name11_12[j];
451 if (l_name[*idx] == 0x00)
452 return 1;
453 (*idx)++;
454 }
455
456 return 0;
457 }
458
459 /* Calculate short name checksum */
460 static __u8 mkcksum(const char name[8], const char ext[3])
461 {
462 int i;
463
464 __u8 ret = 0;
465
466 for (i = 0; i < 8; i++)
467 ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
468 for (i = 0; i < 3; i++)
469 ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
470
471 return ret;
472 }
473
474 /*
475 * TODO these should go away once fat_write is reworked to use the
476 * directory iterator
477 */
478 __u8 get_dentfromdir_block[MAX_CLUSTSIZE]
479 __aligned(ARCH_DMA_MINALIGN);
480 __u8 do_fat_read_at_block[MAX_CLUSTSIZE]
481 __aligned(ARCH_DMA_MINALIGN);
482
483 /*
484 * Read boot sector and volume info from a FAT filesystem
485 */
486 static int
487 read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
488 {
489 __u8 *block;
490 volume_info *vistart;
491 int ret = 0;
492
493 if (cur_dev == NULL) {
494 debug("Error: no device selected\n");
495 return -1;
496 }
497
498 block = memalign(ARCH_DMA_MINALIGN, cur_dev->blksz);
499 if (block == NULL) {
500 debug("Error: allocating block\n");
501 return -1;
502 }
503
504 if (disk_read(0, 1, block) < 0) {
505 debug("Error: reading block\n");
506 goto fail;
507 }
508
509 memcpy(bs, block, sizeof(boot_sector));
510 bs->reserved = FAT2CPU16(bs->reserved);
511 bs->fat_length = FAT2CPU16(bs->fat_length);
512 bs->secs_track = FAT2CPU16(bs->secs_track);
513 bs->heads = FAT2CPU16(bs->heads);
514 bs->total_sect = FAT2CPU32(bs->total_sect);
515
516 /* FAT32 entries */
517 if (bs->fat_length == 0) {
518 /* Assume FAT32 */
519 bs->fat32_length = FAT2CPU32(bs->fat32_length);
520 bs->flags = FAT2CPU16(bs->flags);
521 bs->root_cluster = FAT2CPU32(bs->root_cluster);
522 bs->info_sector = FAT2CPU16(bs->info_sector);
523 bs->backup_boot = FAT2CPU16(bs->backup_boot);
524 vistart = (volume_info *)(block + sizeof(boot_sector));
525 *fatsize = 32;
526 } else {
527 vistart = (volume_info *)&(bs->fat32_length);
528 *fatsize = 0;
529 }
530 memcpy(volinfo, vistart, sizeof(volume_info));
531
532 if (*fatsize == 32) {
533 if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
534 goto exit;
535 } else {
536 if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
537 *fatsize = 12;
538 goto exit;
539 }
540 if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
541 *fatsize = 16;
542 goto exit;
543 }
544 }
545
546 debug("Error: broken fs_type sign\n");
547 fail:
548 ret = -1;
549 exit:
550 free(block);
551 return ret;
552 }
553
554 static int get_fs_info(fsdata *mydata)
555 {
556 boot_sector bs;
557 volume_info volinfo;
558 int ret;
559
560 ret = read_bootsectandvi(&bs, &volinfo, &mydata->fatsize);
561 if (ret) {
562 debug("Error: reading boot sector\n");
563 return ret;
564 }
565
566 if (mydata->fatsize == 32) {
567 mydata->fatlength = bs.fat32_length;
568 } else {
569 mydata->fatlength = bs.fat_length;
570 }
571
572 mydata->fat_sect = bs.reserved;
573
574 mydata->rootdir_sect = mydata->fat_sect + mydata->fatlength * bs.fats;
575
576 mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
577 mydata->clust_size = bs.cluster_size;
578 if (mydata->sect_size != cur_part_info.blksz) {
579 printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
580 mydata->sect_size, cur_part_info.blksz);
581 return -1;
582 }
583
584 if (mydata->fatsize == 32) {
585 mydata->data_begin = mydata->rootdir_sect -
586 (mydata->clust_size * 2);
587 mydata->root_cluster = bs.root_cluster;
588 } else {
589 mydata->rootdir_size = ((bs.dir_entries[1] * (int)256 +
590 bs.dir_entries[0]) *
591 sizeof(dir_entry)) /
592 mydata->sect_size;
593 mydata->data_begin = mydata->rootdir_sect +
594 mydata->rootdir_size -
595 (mydata->clust_size * 2);
596 mydata->root_cluster =
597 sect_to_clust(mydata, mydata->rootdir_sect);
598 }
599
600 mydata->fatbufnum = -1;
601 mydata->fat_dirty = 0;
602 mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
603 if (mydata->fatbuf == NULL) {
604 debug("Error: allocating memory\n");
605 return -1;
606 }
607
608 if (vfat_enabled)
609 debug("VFAT Support enabled\n");
610
611 debug("FAT%d, fat_sect: %d, fatlength: %d\n",
612 mydata->fatsize, mydata->fat_sect, mydata->fatlength);
613 debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
614 "Data begins at: %d\n",
615 mydata->root_cluster,
616 mydata->rootdir_sect,
617 mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
618 debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
619 mydata->clust_size);
620
621 return 0;
622 }
623
624
625 /*
626 * Directory iterator, to simplify filesystem traversal
627 *
628 * Implements an iterator pattern to traverse directory tables,
629 * transparently handling directory tables split across multiple
630 * clusters, and the difference between FAT12/FAT16 root directory
631 * (contiguous) and subdirectories + FAT32 root (chained).
632 *
633 * Rough usage:
634 *
635 * for (fat_itr_root(&itr, fsdata); fat_itr_next(&itr); ) {
636 * // to traverse down to a subdirectory pointed to by
637 * // current iterator position:
638 * fat_itr_child(&itr, &itr);
639 * }
640 *
641 * For more complete example, see fat_itr_resolve()
642 */
643
644 typedef struct {
645 fsdata *fsdata; /* filesystem parameters */
646 unsigned clust; /* current cluster */
647 int last_cluster; /* set once we've read last cluster */
648 int is_root; /* is iterator at root directory */
649 int remaining; /* remaining dent's in current cluster */
650
651 /* current iterator position values: */
652 dir_entry *dent; /* current directory entry */
653 char l_name[VFAT_MAXLEN_BYTES]; /* long (vfat) name */
654 char s_name[14]; /* short 8.3 name */
655 char *name; /* l_name if there is one, else s_name */
656
657 /* storage for current cluster in memory: */
658 u8 block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
659 } fat_itr;
660
661 static int fat_itr_isdir(fat_itr *itr);
662
663 /**
664 * fat_itr_root() - initialize an iterator to start at the root
665 * directory
666 *
667 * @itr: iterator to initialize
668 * @fsdata: filesystem data for the partition
669 * @return 0 on success, else -errno
670 */
671 static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
672 {
673 if (get_fs_info(fsdata))
674 return -ENXIO;
675
676 itr->fsdata = fsdata;
677 itr->clust = fsdata->root_cluster;
678 itr->dent = NULL;
679 itr->remaining = 0;
680 itr->last_cluster = 0;
681 itr->is_root = 1;
682
683 return 0;
684 }
685
686 /**
687 * fat_itr_child() - initialize an iterator to descend into a sub-
688 * directory
689 *
690 * Initializes 'itr' to iterate the contents of the directory at
691 * the current cursor position of 'parent'. It is an error to
692 * call this if the current cursor of 'parent' is pointing at a
693 * regular file.
694 *
695 * Note that 'itr' and 'parent' can be the same pointer if you do
696 * not need to preserve 'parent' after this call, which is useful
697 * for traversing directory structure to resolve a file/directory.
698 *
699 * @itr: iterator to initialize
700 * @parent: the iterator pointing at a directory entry in the
701 * parent directory of the directory to iterate
702 */
703 static void fat_itr_child(fat_itr *itr, fat_itr *parent)
704 {
705 fsdata *mydata = parent->fsdata; /* for silly macros */
706 unsigned clustnum = START(parent->dent);
707
708 assert(fat_itr_isdir(parent));
709
710 itr->fsdata = parent->fsdata;
711 if (clustnum > 0) {
712 itr->clust = clustnum;
713 itr->is_root = 0;
714 } else {
715 itr->clust = parent->fsdata->root_cluster;
716 itr->is_root = 1;
717 }
718 itr->dent = NULL;
719 itr->remaining = 0;
720 itr->last_cluster = 0;
721 }
722
723 static void *next_cluster(fat_itr *itr)
724 {
725 fsdata *mydata = itr->fsdata; /* for silly macros */
726 int ret;
727 u32 sect;
728
729 /* have we reached the end? */
730 if (itr->last_cluster)
731 return NULL;
732
733 sect = clust_to_sect(itr->fsdata, itr->clust);
734
735 debug("FAT read(sect=%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
736 sect, itr->fsdata->clust_size, DIRENTSPERBLOCK);
737
738 /*
739 * NOTE: do_fat_read_at() had complicated logic to deal w/
740 * vfat names that span multiple clusters in the fat16 case,
741 * which get_dentfromdir() probably also needed (and was
742 * missing). And not entirely sure what fat32 didn't have
743 * the same issue.. We solve that by only caring about one
744 * dent at a time and iteratively constructing the vfat long
745 * name.
746 */
747 ret = disk_read(sect, itr->fsdata->clust_size,
748 itr->block);
749 if (ret < 0) {
750 debug("Error: reading block\n");
751 return NULL;
752 }
753
754 if (itr->is_root && itr->fsdata->fatsize != 32) {
755 itr->clust++;
756 sect = clust_to_sect(itr->fsdata, itr->clust);
757 if (sect - itr->fsdata->rootdir_sect >=
758 itr->fsdata->rootdir_size) {
759 debug("cursect: 0x%x\n", itr->clust);
760 itr->last_cluster = 1;
761 }
762 } else {
763 itr->clust = get_fatent(itr->fsdata, itr->clust);
764 if (CHECK_CLUST(itr->clust, itr->fsdata->fatsize)) {
765 debug("cursect: 0x%x\n", itr->clust);
766 itr->last_cluster = 1;
767 }
768 }
769
770 return itr->block;
771 }
772
773 static dir_entry *next_dent(fat_itr *itr)
774 {
775 if (itr->remaining == 0) {
776 struct dir_entry *dent = next_cluster(itr);
777 unsigned nbytes = itr->fsdata->sect_size *
778 itr->fsdata->clust_size;
779
780 /* have we reached the last cluster? */
781 if (!dent)
782 return NULL;
783
784 itr->remaining = nbytes / sizeof(dir_entry) - 1;
785 itr->dent = dent;
786 } else {
787 itr->remaining--;
788 itr->dent++;
789 }
790
791 /* have we reached the last valid entry? */
792 if (itr->dent->name[0] == 0)
793 return NULL;
794
795 return itr->dent;
796 }
797
798 static dir_entry *extract_vfat_name(fat_itr *itr)
799 {
800 struct dir_entry *dent = itr->dent;
801 int seqn = itr->dent->name[0] & ~LAST_LONG_ENTRY_MASK;
802 u8 chksum, alias_checksum = ((dir_slot *)dent)->alias_checksum;
803 int n = 0;
804
805 while (seqn--) {
806 char buf[13];
807 int idx = 0;
808
809 slot2str((dir_slot *)dent, buf, &idx);
810
811 /* shift accumulated long-name up and copy new part in: */
812 memmove(itr->l_name + idx, itr->l_name, n);
813 memcpy(itr->l_name, buf, idx);
814 n += idx;
815
816 dent = next_dent(itr);
817 if (!dent)
818 return NULL;
819 }
820
821 itr->l_name[n] = '\0';
822
823 chksum = mkcksum(dent->name, dent->ext);
824
825 /* checksum mismatch could mean deleted file, etc.. skip it: */
826 if (chksum != alias_checksum) {
827 debug("** chksum=%x, alias_checksum=%x, l_name=%s, s_name=%8s.%3s\n",
828 chksum, alias_checksum, itr->l_name, dent->name, dent->ext);
829 return NULL;
830 }
831
832 return dent;
833 }
834
835 /**
836 * fat_itr_next() - step to the next entry in a directory
837 *
838 * Must be called once on a new iterator before the cursor is valid.
839 *
840 * @itr: the iterator to iterate
841 * @return boolean, 1 if success or 0 if no more entries in the
842 * current directory
843 */
844 static int fat_itr_next(fat_itr *itr)
845 {
846 dir_entry *dent;
847
848 itr->name = NULL;
849
850 while (1) {
851 dent = next_dent(itr);
852 if (!dent)
853 return 0;
854
855 if (dent->name[0] == DELETED_FLAG ||
856 dent->name[0] == aRING)
857 continue;
858
859 if (dent->attr & ATTR_VOLUME) {
860 if (vfat_enabled &&
861 (dent->attr & ATTR_VFAT) == ATTR_VFAT &&
862 (dent->name[0] & LAST_LONG_ENTRY_MASK)) {
863 dent = extract_vfat_name(itr);
864 if (!dent)
865 continue;
866 itr->name = itr->l_name;
867 break;
868 } else {
869 /* Volume label or VFAT entry, skip */
870 continue;
871 }
872 }
873
874 break;
875 }
876
877 get_name(dent, itr->s_name);
878 if (!itr->name)
879 itr->name = itr->s_name;
880
881 return 1;
882 }
883
884 /**
885 * fat_itr_isdir() - is current cursor position pointing to a directory
886 *
887 * @itr: the iterator
888 * @return true if cursor is at a directory
889 */
890 static int fat_itr_isdir(fat_itr *itr)
891 {
892 return !!(itr->dent->attr & ATTR_DIR);
893 }
894
895 /*
896 * Helpers:
897 */
898
899 #define TYPE_FILE 0x1
900 #define TYPE_DIR 0x2
901 #define TYPE_ANY (TYPE_FILE | TYPE_DIR)
902
903 /**
904 * fat_itr_resolve() - traverse directory structure to resolve the
905 * requested path.
906 *
907 * Traverse directory structure to the requested path. If the specified
908 * path is to a directory, this will descend into the directory and
909 * leave it iterator at the start of the directory. If the path is to a
910 * file, it will leave the iterator in the parent directory with current
911 * cursor at file's entry in the directory.
912 *
913 * @itr: iterator initialized to root
914 * @path: the requested path
915 * @type: bitmask of allowable file types
916 * @return 0 on success or -errno
917 */
918 static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
919 {
920 const char *next;
921
922 /* chomp any extra leading slashes: */
923 while (path[0] && ISDIRDELIM(path[0]))
924 path++;
925
926 /* are we at the end? */
927 if (strlen(path) == 0) {
928 if (!(type & TYPE_DIR))
929 return -ENOENT;
930 return 0;
931 }
932
933 /* find length of next path entry: */
934 next = path;
935 while (next[0] && !ISDIRDELIM(next[0]))
936 next++;
937
938 while (fat_itr_next(itr)) {
939 int match = 0;
940 unsigned n = max(strlen(itr->name), (size_t)(next - path));
941
942 /* check both long and short name: */
943 if (!strncasecmp(path, itr->name, n))
944 match = 1;
945 else if (itr->name != itr->s_name &&
946 !strncasecmp(path, itr->s_name, n))
947 match = 1;
948
949 if (!match)
950 continue;
951
952 if (fat_itr_isdir(itr)) {
953 /* recurse into directory: */
954 fat_itr_child(itr, itr);
955 return fat_itr_resolve(itr, next, type);
956 } else if (next[0]) {
957 /*
958 * If next is not empty then we have a case
959 * like: /path/to/realfile/nonsense
960 */
961 debug("bad trailing path: %s\n", next);
962 return -ENOENT;
963 } else if (!(type & TYPE_FILE)) {
964 return -ENOTDIR;
965 } else {
966 return 0;
967 }
968 }
969
970 return -ENOENT;
971 }
972
973 int file_fat_detectfs(void)
974 {
975 boot_sector bs;
976 volume_info volinfo;
977 int fatsize;
978 char vol_label[12];
979
980 if (cur_dev == NULL) {
981 printf("No current device\n");
982 return 1;
983 }
984
985 #if defined(CONFIG_IDE) || \
986 defined(CONFIG_SATA) || \
987 defined(CONFIG_SCSI) || \
988 defined(CONFIG_CMD_USB) || \
989 defined(CONFIG_MMC)
990 printf("Interface: ");
991 switch (cur_dev->if_type) {
992 case IF_TYPE_IDE:
993 printf("IDE");
994 break;
995 case IF_TYPE_SATA:
996 printf("SATA");
997 break;
998 case IF_TYPE_SCSI:
999 printf("SCSI");
1000 break;
1001 case IF_TYPE_ATAPI:
1002 printf("ATAPI");
1003 break;
1004 case IF_TYPE_USB:
1005 printf("USB");
1006 break;
1007 case IF_TYPE_DOC:
1008 printf("DOC");
1009 break;
1010 case IF_TYPE_MMC:
1011 printf("MMC");
1012 break;
1013 default:
1014 printf("Unknown");
1015 }
1016
1017 printf("\n Device %d: ", cur_dev->devnum);
1018 dev_print(cur_dev);
1019 #endif
1020
1021 if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1022 printf("\nNo valid FAT fs found\n");
1023 return 1;
1024 }
1025
1026 memcpy(vol_label, volinfo.volume_label, 11);
1027 vol_label[11] = '\0';
1028 volinfo.fs_type[5] = '\0';
1029
1030 printf("Filesystem: %s \"%s\"\n", volinfo.fs_type, vol_label);
1031
1032 return 0;
1033 }
1034
1035 int fat_exists(const char *filename)
1036 {
1037 fsdata fsdata;
1038 fat_itr *itr;
1039 int ret;
1040
1041 itr = malloc(sizeof(fat_itr));
1042 ret = fat_itr_root(itr, &fsdata);
1043 if (ret)
1044 return 0;
1045
1046 ret = fat_itr_resolve(itr, filename, TYPE_ANY);
1047 free(fsdata.fatbuf);
1048 free(itr);
1049 return ret == 0;
1050 }
1051
1052 int fat_size(const char *filename, loff_t *size)
1053 {
1054 fsdata fsdata;
1055 fat_itr *itr;
1056 int ret;
1057
1058 itr = malloc(sizeof(fat_itr));
1059 ret = fat_itr_root(itr, &fsdata);
1060 if (ret)
1061 return ret;
1062
1063 ret = fat_itr_resolve(itr, filename, TYPE_FILE);
1064 if (ret) {
1065 /*
1066 * Directories don't have size, but fs_size() is not
1067 * expected to fail if passed a directory path:
1068 */
1069 free(fsdata.fatbuf);
1070 fat_itr_root(itr, &fsdata);
1071 if (!fat_itr_resolve(itr, filename, TYPE_DIR)) {
1072 *size = 0;
1073 ret = 0;
1074 }
1075 goto out;
1076 }
1077
1078 *size = FAT2CPU32(itr->dent->size);
1079 free(fsdata.fatbuf);
1080 out:
1081 free(itr);
1082 return ret;
1083 }
1084
1085 int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
1086 loff_t maxsize, loff_t *actread)
1087 {
1088 fsdata fsdata;
1089 fat_itr *itr;
1090 int ret;
1091
1092 itr = malloc(sizeof(fat_itr));
1093 ret = fat_itr_root(itr, &fsdata);
1094 if (ret)
1095 return ret;
1096
1097 ret = fat_itr_resolve(itr, filename, TYPE_FILE);
1098 if (ret)
1099 goto out;
1100
1101 printf("reading %s\n", filename);
1102 ret = get_contents(&fsdata, itr->dent, pos, buffer, maxsize, actread);
1103
1104 out:
1105 free(fsdata.fatbuf);
1106 free(itr);
1107 return ret;
1108 }
1109
1110 int file_fat_read(const char *filename, void *buffer, int maxsize)
1111 {
1112 loff_t actread;
1113 int ret;
1114
1115 ret = file_fat_read_at(filename, 0, buffer, maxsize, &actread);
1116 if (ret)
1117 return ret;
1118 else
1119 return actread;
1120 }
1121
1122 int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
1123 loff_t *actread)
1124 {
1125 int ret;
1126
1127 ret = file_fat_read_at(filename, offset, buf, len, actread);
1128 if (ret)
1129 printf("** Unable to read file %s **\n", filename);
1130
1131 return ret;
1132 }
1133
1134 typedef struct {
1135 struct fs_dir_stream parent;
1136 struct fs_dirent dirent;
1137 fsdata fsdata;
1138 fat_itr itr;
1139 } fat_dir;
1140
1141 int fat_opendir(const char *filename, struct fs_dir_stream **dirsp)
1142 {
1143 fat_dir *dir = calloc(1, sizeof(*dir));
1144 int ret;
1145
1146 if (!dir)
1147 return -ENOMEM;
1148
1149 ret = fat_itr_root(&dir->itr, &dir->fsdata);
1150 if (ret)
1151 goto fail;
1152
1153 ret = fat_itr_resolve(&dir->itr, filename, TYPE_DIR);
1154 if (ret)
1155 goto fail;
1156
1157 *dirsp = (struct fs_dir_stream *)dir;
1158 return 0;
1159
1160 fail:
1161 free(dir->fsdata.fatbuf);
1162 free(dir);
1163 return ret;
1164 }
1165
1166 int fat_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp)
1167 {
1168 fat_dir *dir = (fat_dir *)dirs;
1169 struct fs_dirent *dent = &dir->dirent;
1170
1171 if (!fat_itr_next(&dir->itr))
1172 return -ENOENT;
1173
1174 memset(dent, 0, sizeof(*dent));
1175 strcpy(dent->name, dir->itr.name);
1176
1177 if (fat_itr_isdir(&dir->itr)) {
1178 dent->type = FS_DT_DIR;
1179 } else {
1180 dent->type = FS_DT_REG;
1181 dent->size = FAT2CPU32(dir->itr.dent->size);
1182 }
1183
1184 *dentp = dent;
1185
1186 return 0;
1187 }
1188
1189 void fat_closedir(struct fs_dir_stream *dirs)
1190 {
1191 fat_dir *dir = (fat_dir *)dirs;
1192 free(dir->fsdata.fatbuf);
1193 free(dir);
1194 }
1195
1196 void fat_close(void)
1197 {
1198 }