1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * fat.c
4 *
5 * R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
6 *
7 * 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
8 * 2003-03-10 - kharris@nexus-tech.net - ported to uboot
9 */
10
11 #include <common.h>
12 #include <blk.h>
13 #include <config.h>
14 #include <exports.h>
15 #include <fat.h>
16 #include <fs.h>
17 #include <log.h>
18 #include <asm/byteorder.h>
19 #include <part.h>
20 #include <malloc.h>
21 #include <memalign.h>
22 #include <asm/cache.h>
23 #include <linux/compiler.h>
24 #include <linux/ctype.h>
25
26 /*
27 * Convert a string to lowercase. Converts at most 'len' characters,
28 * 'len' may be larger than the length of 'str' if 'str' is NULL
29 * terminated.
30 */
downcase(char * str,size_t len)31 static void downcase(char *str, size_t len)
32 {
33 while (*str != '\0' && len--) {
34 *str = tolower(*str);
35 str++;
36 }
37 }
38
39 static struct blk_desc *cur_dev;
40 static struct disk_partition cur_part_info;
41
42 #define DOS_BOOT_MAGIC_OFFSET 0x1fe
43 #define DOS_FS_TYPE_OFFSET 0x36
44 #define DOS_FS32_TYPE_OFFSET 0x52
45
disk_read(__u32 block,__u32 nr_blocks,void * buf)46 static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
47 {
48 ulong ret;
49
50 if (!cur_dev)
51 return -1;
52
53 ret = blk_dread(cur_dev, cur_part_info.start + block, nr_blocks, buf);
54
55 if (ret != nr_blocks)
56 return -1;
57
58 return ret;
59 }
60
fat_set_blk_dev(struct blk_desc * dev_desc,struct disk_partition * info)61 int fat_set_blk_dev(struct blk_desc *dev_desc, struct disk_partition *info)
62 {
63 ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
64
65 cur_dev = dev_desc;
66 cur_part_info = *info;
67
68 /* Make sure it has a valid FAT header */
69 if (disk_read(0, 1, buffer) != 1) {
70 cur_dev = NULL;
71 return -1;
72 }
73
74 /* Check if it's actually a DOS volume */
75 if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
76 cur_dev = NULL;
77 return -1;
78 }
79
80 /* Check for FAT12/FAT16/FAT32 filesystem */
81 if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
82 return 0;
83 if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
84 return 0;
85
86 cur_dev = NULL;
87 return -1;
88 }
89
fat_register_device(struct blk_desc * dev_desc,int part_no)90 int fat_register_device(struct blk_desc *dev_desc, int part_no)
91 {
92 struct disk_partition info;
93
94 /* First close any currently found FAT filesystem */
95 cur_dev = NULL;
96
97 /* Read the partition table, if present */
98 if (part_get_info(dev_desc, part_no, &info)) {
99 if (part_no != 0) {
100 printf("** Partition %d not valid on device %d **\n",
101 part_no, dev_desc->devnum);
102 return -1;
103 }
104
105 info.start = 0;
106 info.size = dev_desc->lba;
107 info.blksz = dev_desc->blksz;
108 info.name[0] = 0;
109 info.type[0] = 0;
110 info.bootable = 0;
111 #if CONFIG_IS_ENABLED(PARTITION_UUIDS)
112 info.uuid[0] = 0;
113 #endif
114 }
115
116 return fat_set_blk_dev(dev_desc, &info);
117 }
118
119 /*
120 * Extract zero terminated short name from a directory entry.
121 */
get_name(dir_entry * dirent,char * s_name)122 static void get_name(dir_entry *dirent, char *s_name)
123 {
124 char *ptr;
125
126 memcpy(s_name, dirent->nameext.name, 8);
127 s_name[8] = '\0';
128 ptr = s_name;
129 while (*ptr && *ptr != ' ')
130 ptr++;
131 if (dirent->lcase & CASE_LOWER_BASE)
132 downcase(s_name, (unsigned)(ptr - s_name));
133 if (dirent->nameext.ext[0] && dirent->nameext.ext[0] != ' ') {
134 *ptr++ = '.';
135 memcpy(ptr, dirent->nameext.ext, 3);
136 if (dirent->lcase & CASE_LOWER_EXT)
137 downcase(ptr, 3);
138 ptr[3] = '\0';
139 while (*ptr && *ptr != ' ')
140 ptr++;
141 }
142 *ptr = '\0';
143 if (*s_name == DELETED_FLAG)
144 *s_name = '\0';
145 else if (*s_name == aRING)
146 *s_name = DELETED_FLAG;
147 }
148
149 static int flush_dirty_fat_buffer(fsdata *mydata);
150
151 #if !CONFIG_IS_ENABLED(FAT_WRITE)
152 /* Stub for read only operation */
flush_dirty_fat_buffer(fsdata * mydata)153 int flush_dirty_fat_buffer(fsdata *mydata)
154 {
155 (void)(mydata);
156 return 0;
157 }
158 #endif
159
160 /*
161 * Get the entry at index 'entry' in a FAT (12/16/32) table.
162 * On failure 0x00 is returned.
163 */
get_fatent(fsdata * mydata,__u32 entry)164 static __u32 get_fatent(fsdata *mydata, __u32 entry)
165 {
166 __u32 bufnum;
167 __u32 offset, off8;
168 __u32 ret = 0x00;
169
170 if (CHECK_CLUST(entry, mydata->fatsize)) {
171 printf("Error: Invalid FAT entry: 0x%08x\n", entry);
172 return ret;
173 }
174
175 switch (mydata->fatsize) {
176 case 32:
177 bufnum = entry / FAT32BUFSIZE;
178 offset = entry - bufnum * FAT32BUFSIZE;
179 break;
180 case 16:
181 bufnum = entry / FAT16BUFSIZE;
182 offset = entry - bufnum * FAT16BUFSIZE;
183 break;
184 case 12:
185 bufnum = entry / FAT12BUFSIZE;
186 offset = entry - bufnum * FAT12BUFSIZE;
187 break;
188
189 default:
190 /* Unsupported FAT size */
191 return ret;
192 }
193
194 debug("FAT%d: entry: 0x%08x = %d, offset: 0x%04x = %d\n",
195 mydata->fatsize, entry, entry, offset, offset);
196
197 /* Read a new block of FAT entries into the cache. */
198 if (bufnum != mydata->fatbufnum) {
199 __u32 getsize = FATBUFBLOCKS;
200 __u8 *bufptr = mydata->fatbuf;
201 __u32 fatlength = mydata->fatlength;
202 __u32 startblock = bufnum * FATBUFBLOCKS;
203
204 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
205 if (startblock + getsize > fatlength)
206 getsize = fatlength - startblock;
207
208 startblock += mydata->fat_sect; /* Offset from start of disk */
209
210 /* Write back the fatbuf to the disk */
211 if (flush_dirty_fat_buffer(mydata) < 0)
212 return -1;
213
214 if (disk_read(startblock, getsize, bufptr) < 0) {
215 debug("Error reading FAT blocks\n");
216 return ret;
217 }
218 mydata->fatbufnum = bufnum;
219 }
220
221 /* Get the actual entry from the table */
222 switch (mydata->fatsize) {
223 case 32:
224 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
225 break;
226 case 16:
227 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
228 break;
229 case 12:
230 off8 = (offset * 3) / 2;
231 /* fatbut + off8 may be unaligned, read in byte granularity */
232 ret = mydata->fatbuf[off8] + (mydata->fatbuf[off8 + 1] << 8);
233
234 if (offset & 0x1)
235 ret >>= 4;
236 ret &= 0xfff;
237 }
238 debug("FAT%d: ret: 0x%08x, entry: 0x%08x, offset: 0x%04x\n",
239 mydata->fatsize, ret, entry, offset);
240
241 return ret;
242 }
243
244 /*
245 * Read at most 'size' bytes from the specified cluster into 'buffer'.
246 * Return 0 on success, -1 otherwise.
247 */
248 static int
get_cluster(fsdata * mydata,__u32 clustnum,__u8 * buffer,unsigned long size)249 get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
250 {
251 __u32 startsect;
252 int ret;
253
254 if (clustnum > 0) {
255 startsect = clust_to_sect(mydata, clustnum);
256 } else {
257 startsect = mydata->rootdir_sect;
258 }
259
260 debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
261
262 if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
263 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
264
265 debug("FAT: Misaligned buffer address (%p)\n", buffer);
266
267 while (size >= mydata->sect_size) {
268 ret = disk_read(startsect++, 1, tmpbuf);
269 if (ret != 1) {
270 debug("Error reading data (got %d)\n", ret);
271 return -1;
272 }
273
274 memcpy(buffer, tmpbuf, mydata->sect_size);
275 buffer += mydata->sect_size;
276 size -= mydata->sect_size;
277 }
278 } else {
279 __u32 idx;
280
281 idx = size / mydata->sect_size;
282 if (idx == 0)
283 ret = 0;
284 else
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 * get_contents() - read from file
312 *
313 * Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
314 * into 'buffer'. Update the number of bytes read in *gotsize or return -1 on
315 * fatal errors.
316 *
317 * @mydata: file system description
318 * @dentprt: directory entry pointer
319 * @pos: position from where to read
320 * @buffer: buffer into which to read
321 * @maxsize: maximum number of bytes to read
322 * @gotsize: number of bytes actually read
323 * Return: -1 on error, otherwise 0
324 */
get_contents(fsdata * mydata,dir_entry * dentptr,loff_t pos,__u8 * buffer,loff_t maxsize,loff_t * gotsize)325 static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
326 __u8 *buffer, loff_t maxsize, loff_t *gotsize)
327 {
328 loff_t filesize = FAT2CPU32(dentptr->size);
329 unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
330 __u32 curclust = START(dentptr);
331 __u32 endclust, newclust;
332 loff_t actsize;
333
334 *gotsize = 0;
335 debug("Filesize: %llu bytes\n", filesize);
336
337 if (pos >= filesize) {
338 debug("Read position past EOF: %llu\n", pos);
339 return 0;
340 }
341
342 if (maxsize > 0 && filesize > pos + maxsize)
343 filesize = pos + maxsize;
344
345 debug("%llu bytes\n", filesize);
346
347 actsize = bytesperclust;
348
349 /* go to cluster at pos */
350 while (actsize <= pos) {
351 curclust = get_fatent(mydata, curclust);
352 if (CHECK_CLUST(curclust, mydata->fatsize)) {
353 debug("curclust: 0x%x\n", curclust);
354 printf("Invalid FAT entry\n");
355 return -1;
356 }
357 actsize += bytesperclust;
358 }
359
360 /* actsize > pos */
361 actsize -= bytesperclust;
362 filesize -= actsize;
363 pos -= actsize;
364
365 /* align to beginning of next cluster if any */
366 if (pos) {
367 __u8 *tmp_buffer;
368
369 actsize = min(filesize, (loff_t)bytesperclust);
370 tmp_buffer = malloc_cache_aligned(actsize);
371 if (!tmp_buffer) {
372 debug("Error: allocating buffer\n");
373 return -1;
374 }
375
376 if (get_cluster(mydata, curclust, tmp_buffer, actsize) != 0) {
377 printf("Error reading cluster\n");
378 free(tmp_buffer);
379 return -1;
380 }
381 filesize -= actsize;
382 actsize -= pos;
383 memcpy(buffer, tmp_buffer + pos, actsize);
384 free(tmp_buffer);
385 *gotsize += actsize;
386 if (!filesize)
387 return 0;
388 buffer += actsize;
389
390 curclust = get_fatent(mydata, curclust);
391 if (CHECK_CLUST(curclust, mydata->fatsize)) {
392 debug("curclust: 0x%x\n", curclust);
393 printf("Invalid FAT entry\n");
394 return -1;
395 }
396 }
397
398 actsize = bytesperclust;
399 endclust = curclust;
400
401 do {
402 /* search for consecutive clusters */
403 while (actsize < filesize) {
404 newclust = get_fatent(mydata, endclust);
405 if ((newclust - 1) != endclust)
406 goto getit;
407 if (CHECK_CLUST(newclust, mydata->fatsize)) {
408 debug("curclust: 0x%x\n", newclust);
409 printf("Invalid FAT entry\n");
410 return -1;
411 }
412 endclust = newclust;
413 actsize += bytesperclust;
414 }
415
416 /* get remaining bytes */
417 actsize = filesize;
418 if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
419 printf("Error reading cluster\n");
420 return -1;
421 }
422 *gotsize += actsize;
423 return 0;
424 getit:
425 if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
426 printf("Error reading cluster\n");
427 return -1;
428 }
429 *gotsize += (int)actsize;
430 filesize -= actsize;
431 buffer += actsize;
432
433 curclust = get_fatent(mydata, endclust);
434 if (CHECK_CLUST(curclust, mydata->fatsize)) {
435 debug("curclust: 0x%x\n", curclust);
436 printf("Invalid FAT entry\n");
437 return -1;
438 }
439 actsize = bytesperclust;
440 endclust = curclust;
441 } while (1);
442 }
443
444 /*
445 * Extract the file name information from 'slotptr' into 'l_name',
446 * starting at l_name[*idx].
447 * Return 1 if terminator (zero byte) is found, 0 otherwise.
448 */
slot2str(dir_slot * slotptr,char * l_name,int * idx)449 static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
450 {
451 int j;
452
453 for (j = 0; j <= 8; j += 2) {
454 l_name[*idx] = slotptr->name0_4[j];
455 if (l_name[*idx] == 0x00)
456 return 1;
457 (*idx)++;
458 }
459 for (j = 0; j <= 10; j += 2) {
460 l_name[*idx] = slotptr->name5_10[j];
461 if (l_name[*idx] == 0x00)
462 return 1;
463 (*idx)++;
464 }
465 for (j = 0; j <= 2; j += 2) {
466 l_name[*idx] = slotptr->name11_12[j];
467 if (l_name[*idx] == 0x00)
468 return 1;
469 (*idx)++;
470 }
471
472 return 0;
473 }
474
475 /* Calculate short name checksum */
mkcksum(struct nameext * nameext)476 static __u8 mkcksum(struct nameext *nameext)
477 {
478 int i;
479 u8 *pos = (void *)nameext;
480
481 __u8 ret = 0;
482
483 for (i = 0; i < 11; i++)
484 ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + pos[i];
485
486 return ret;
487 }
488
489 /*
490 * Read boot sector and volume info from a FAT filesystem
491 */
492 static int
read_bootsectandvi(boot_sector * bs,volume_info * volinfo,int * fatsize)493 read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
494 {
495 __u8 *block;
496 volume_info *vistart;
497 int ret = 0;
498
499 if (cur_dev == NULL) {
500 debug("Error: no device selected\n");
501 return -1;
502 }
503
504 block = malloc_cache_aligned(cur_dev->blksz);
505 if (block == NULL) {
506 debug("Error: allocating block\n");
507 return -1;
508 }
509
510 if (disk_read(0, 1, block) < 0) {
511 debug("Error: reading block\n");
512 goto fail;
513 }
514
515 memcpy(bs, block, sizeof(boot_sector));
516 bs->reserved = FAT2CPU16(bs->reserved);
517 bs->fat_length = FAT2CPU16(bs->fat_length);
518 bs->secs_track = FAT2CPU16(bs->secs_track);
519 bs->heads = FAT2CPU16(bs->heads);
520 bs->total_sect = FAT2CPU32(bs->total_sect);
521
522 /* FAT32 entries */
523 if (bs->fat_length == 0) {
524 /* Assume FAT32 */
525 bs->fat32_length = FAT2CPU32(bs->fat32_length);
526 bs->flags = FAT2CPU16(bs->flags);
527 bs->root_cluster = FAT2CPU32(bs->root_cluster);
528 bs->info_sector = FAT2CPU16(bs->info_sector);
529 bs->backup_boot = FAT2CPU16(bs->backup_boot);
530 vistart = (volume_info *)(block + sizeof(boot_sector));
531 *fatsize = 32;
532 } else {
533 vistart = (volume_info *)&(bs->fat32_length);
534 *fatsize = 0;
535 }
536 memcpy(volinfo, vistart, sizeof(volume_info));
537
538 if (*fatsize == 32) {
539 if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
540 goto exit;
541 } else {
542 if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
543 *fatsize = 12;
544 goto exit;
545 }
546 if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
547 *fatsize = 16;
548 goto exit;
549 }
550 }
551
552 debug("Error: broken fs_type sign\n");
553 fail:
554 ret = -1;
555 exit:
556 free(block);
557 return ret;
558 }
559
get_fs_info(fsdata * mydata)560 static int get_fs_info(fsdata *mydata)
561 {
562 boot_sector bs;
563 volume_info volinfo;
564 int ret;
565
566 ret = read_bootsectandvi(&bs, &volinfo, &mydata->fatsize);
567 if (ret) {
568 debug("Error: reading boot sector\n");
569 return ret;
570 }
571
572 if (mydata->fatsize == 32) {
573 mydata->fatlength = bs.fat32_length;
574 mydata->total_sect = bs.total_sect;
575 } else {
576 mydata->fatlength = bs.fat_length;
577 mydata->total_sect = (bs.sectors[1] << 8) + bs.sectors[0];
578 if (!mydata->total_sect)
579 mydata->total_sect = bs.total_sect;
580 }
581 if (!mydata->total_sect) /* unlikely */
582 mydata->total_sect = (u32)cur_part_info.size;
583
584 mydata->fats = bs.fats;
585 mydata->fat_sect = bs.reserved;
586
587 mydata->rootdir_sect = mydata->fat_sect + mydata->fatlength * bs.fats;
588
589 mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
590 mydata->clust_size = bs.cluster_size;
591 if (mydata->sect_size != cur_part_info.blksz) {
592 printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
593 mydata->sect_size, cur_part_info.blksz);
594 return -1;
595 }
596 if (mydata->clust_size == 0) {
597 printf("Error: FAT cluster size not set\n");
598 return -1;
599 }
600 if ((unsigned int)mydata->clust_size * mydata->sect_size >
601 MAX_CLUSTSIZE) {
602 printf("Error: FAT cluster size too big (cs=%u, max=%u)\n",
603 (unsigned int)mydata->clust_size * mydata->sect_size,
604 MAX_CLUSTSIZE);
605 return -1;
606 }
607
608 if (mydata->fatsize == 32) {
609 mydata->data_begin = mydata->rootdir_sect -
610 (mydata->clust_size * 2);
611 mydata->root_cluster = bs.root_cluster;
612 } else {
613 mydata->rootdir_size = ((bs.dir_entries[1] * (int)256 +
614 bs.dir_entries[0]) *
615 sizeof(dir_entry)) /
616 mydata->sect_size;
617 mydata->data_begin = mydata->rootdir_sect +
618 mydata->rootdir_size -
619 (mydata->clust_size * 2);
620
621 /*
622 * The root directory is not cluster-aligned and may be on a
623 * "negative" cluster, this will be handled specially in
624 * fat_next_cluster().
625 */
626 mydata->root_cluster = 0;
627 }
628
629 mydata->fatbufnum = -1;
630 mydata->fat_dirty = 0;
631 mydata->fatbuf = malloc_cache_aligned(FATBUFSIZE);
632 if (mydata->fatbuf == NULL) {
633 debug("Error: allocating memory\n");
634 return -1;
635 }
636
637 debug("FAT%d, fat_sect: %d, fatlength: %d\n",
638 mydata->fatsize, mydata->fat_sect, mydata->fatlength);
639 debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
640 "Data begins at: %d\n",
641 mydata->root_cluster,
642 mydata->rootdir_sect,
643 mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
644 debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
645 mydata->clust_size);
646
647 return 0;
648 }
649
650 /**
651 * struct fat_itr - directory iterator, to simplify filesystem traversal
652 *
653 * Implements an iterator pattern to traverse directory tables,
654 * transparently handling directory tables split across multiple
655 * clusters, and the difference between FAT12/FAT16 root directory
656 * (contiguous) and subdirectories + FAT32 root (chained).
657 *
658 * Rough usage
659 *
660 * .. code-block:: c
661 *
662 * for (fat_itr_root(&itr, fsdata); fat_itr_next(&itr); ) {
663 * // to traverse down to a subdirectory pointed to by
664 * // current iterator position:
665 * fat_itr_child(&itr, &itr);
666 * }
667 *
668 * For a more complete example, see fat_itr_resolve().
669 */
670 struct fat_itr {
671 /**
672 * @fsdata: filesystem parameters
673 */
674 fsdata *fsdata;
675 /**
676 * @start_clust: first cluster
677 */
678 unsigned int start_clust;
679 /**
680 * @clust: current cluster
681 */
682 unsigned int clust;
683 /**
684 * @next_clust: next cluster if remaining == 0
685 */
686 unsigned int next_clust;
687 /**
688 * @last_cluster: set if last cluster of directory reached
689 */
690 int last_cluster;
691 /**
692 * @is_root: is iterator at root directory
693 */
694 int is_root;
695 /**
696 * @remaining: remaining directory entries in current cluster
697 */
698 int remaining;
699 /**
700 * @dent: current directory entry
701 */
702 dir_entry *dent;
703 /**
704 * @dent_rem: remaining entries after long name start
705 */
706 int dent_rem;
707 /**
708 * @dent_clust: cluster of long name start
709 */
710 unsigned int dent_clust;
711 /**
712 * @dent_start: first directory entry for long name
713 */
714 dir_entry *dent_start;
715 /**
716 * @l_name: long name of current directory entry
717 */
718 char l_name[VFAT_MAXLEN_BYTES];
719 /**
720 * @s_name: short 8.3 name of current directory entry
721 */
722 char s_name[14];
723 /**
724 * @name: l_name if there is one, else s_name
725 */
726 char *name;
727 /**
728 * @block: buffer for current cluster
729 */
730 u8 block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
731 };
732
733 static int fat_itr_isdir(fat_itr *itr);
734
735 /**
736 * fat_itr_root() - initialize an iterator to start at the root
737 * directory
738 *
739 * @itr: iterator to initialize
740 * @fsdata: filesystem data for the partition
741 * @return 0 on success, else -errno
742 */
fat_itr_root(fat_itr * itr,fsdata * fsdata)743 static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
744 {
745 if (get_fs_info(fsdata))
746 return -ENXIO;
747
748 itr->fsdata = fsdata;
749 itr->start_clust = fsdata->root_cluster;
750 itr->clust = fsdata->root_cluster;
751 itr->next_clust = fsdata->root_cluster;
752 itr->dent = NULL;
753 itr->remaining = 0;
754 itr->last_cluster = 0;
755 itr->is_root = 1;
756
757 return 0;
758 }
759
760 /**
761 * fat_itr_child() - initialize an iterator to descend into a sub-
762 * directory
763 *
764 * Initializes 'itr' to iterate the contents of the directory at
765 * the current cursor position of 'parent'. It is an error to
766 * call this if the current cursor of 'parent' is pointing at a
767 * regular file.
768 *
769 * Note that 'itr' and 'parent' can be the same pointer if you do
770 * not need to preserve 'parent' after this call, which is useful
771 * for traversing directory structure to resolve a file/directory.
772 *
773 * @itr: iterator to initialize
774 * @parent: the iterator pointing at a directory entry in the
775 * parent directory of the directory to iterate
776 */
fat_itr_child(fat_itr * itr,fat_itr * parent)777 static void fat_itr_child(fat_itr *itr, fat_itr *parent)
778 {
779 fsdata *mydata = parent->fsdata; /* for silly macros */
780 unsigned clustnum = START(parent->dent);
781
782 assert(fat_itr_isdir(parent));
783
784 itr->fsdata = parent->fsdata;
785 itr->start_clust = clustnum;
786 if (clustnum > 0) {
787 itr->clust = clustnum;
788 itr->next_clust = clustnum;
789 itr->is_root = 0;
790 } else {
791 itr->clust = parent->fsdata->root_cluster;
792 itr->next_clust = parent->fsdata->root_cluster;
793 itr->start_clust = parent->fsdata->root_cluster;
794 itr->is_root = 1;
795 }
796 itr->dent = NULL;
797 itr->remaining = 0;
798 itr->last_cluster = 0;
799 }
800
801 /**
802 * fat_next_cluster() - load next FAT cluster
803 *
804 * The function is used when iterating through directories. It loads the
805 * next cluster with directory entries
806 *
807 * @itr: directory iterator
808 * @nbytes: number of bytes read, 0 on error
809 * Return: first directory entry, NULL on error
810 */
fat_next_cluster(fat_itr * itr,unsigned int * nbytes)811 void *fat_next_cluster(fat_itr *itr, unsigned int *nbytes)
812 {
813 int ret;
814 u32 sect;
815 u32 read_size;
816
817 /* have we reached the end? */
818 if (itr->last_cluster)
819 return NULL;
820
821 if (itr->is_root && itr->fsdata->fatsize != 32) {
822 /*
823 * The root directory is located before the data area and
824 * cannot be indexed using the regular unsigned cluster
825 * numbers (it may start at a "negative" cluster or not at a
826 * cluster boundary at all), so consider itr->next_clust to be
827 * a offset in cluster-sized units from the start of rootdir.
828 */
829 unsigned sect_offset = itr->next_clust * itr->fsdata->clust_size;
830 unsigned remaining_sects = itr->fsdata->rootdir_size - sect_offset;
831 sect = itr->fsdata->rootdir_sect + sect_offset;
832 /* do not read past the end of rootdir */
833 read_size = min_t(u32, itr->fsdata->clust_size,
834 remaining_sects);
835 } else {
836 sect = clust_to_sect(itr->fsdata, itr->next_clust);
837 read_size = itr->fsdata->clust_size;
838 }
839
840 log_debug("FAT read(sect=%d), clust_size=%d, read_size=%u\n",
841 sect, itr->fsdata->clust_size, read_size);
842
843 /*
844 * NOTE: do_fat_read_at() had complicated logic to deal w/
845 * vfat names that span multiple clusters in the fat16 case,
846 * which get_dentfromdir() probably also needed (and was
847 * missing). And not entirely sure what fat32 didn't have
848 * the same issue.. We solve that by only caring about one
849 * dent at a time and iteratively constructing the vfat long
850 * name.
851 */
852 ret = disk_read(sect, read_size, itr->block);
853 if (ret < 0) {
854 debug("Error: reading block\n");
855 return NULL;
856 }
857
858 *nbytes = read_size * itr->fsdata->sect_size;
859 itr->clust = itr->next_clust;
860 if (itr->is_root && itr->fsdata->fatsize != 32) {
861 itr->next_clust++;
862 if (itr->next_clust * itr->fsdata->clust_size >=
863 itr->fsdata->rootdir_size) {
864 debug("nextclust: 0x%x\n", itr->next_clust);
865 itr->last_cluster = 1;
866 }
867 } else {
868 itr->next_clust = get_fatent(itr->fsdata, itr->next_clust);
869 if (CHECK_CLUST(itr->next_clust, itr->fsdata->fatsize)) {
870 debug("nextclust: 0x%x\n", itr->next_clust);
871 itr->last_cluster = 1;
872 }
873 }
874
875 return itr->block;
876 }
877
next_dent(fat_itr * itr)878 static dir_entry *next_dent(fat_itr *itr)
879 {
880 if (itr->remaining == 0) {
881 unsigned nbytes;
882 struct dir_entry *dent = fat_next_cluster(itr, &nbytes);
883
884 /* have we reached the last cluster? */
885 if (!dent) {
886 /* a sign for no more entries left */
887 itr->dent = NULL;
888 return NULL;
889 }
890
891 itr->remaining = nbytes / sizeof(dir_entry) - 1;
892 itr->dent = dent;
893 } else {
894 itr->remaining--;
895 itr->dent++;
896 }
897
898 /* have we reached the last valid entry? */
899 if (itr->dent->nameext.name[0] == 0)
900 return NULL;
901
902 return itr->dent;
903 }
904
extract_vfat_name(fat_itr * itr)905 static dir_entry *extract_vfat_name(fat_itr *itr)
906 {
907 struct dir_entry *dent = itr->dent;
908 int seqn = itr->dent->nameext.name[0] & ~LAST_LONG_ENTRY_MASK;
909 u8 chksum, alias_checksum = ((dir_slot *)dent)->alias_checksum;
910 int n = 0;
911
912 while (seqn--) {
913 char buf[13];
914 int idx = 0;
915
916 slot2str((dir_slot *)dent, buf, &idx);
917
918 if (n + idx >= sizeof(itr->l_name))
919 return NULL;
920
921 /* shift accumulated long-name up and copy new part in: */
922 memmove(itr->l_name + idx, itr->l_name, n);
923 memcpy(itr->l_name, buf, idx);
924 n += idx;
925
926 dent = next_dent(itr);
927 if (!dent)
928 return NULL;
929 }
930
931 /*
932 * We are now at the short file name entry.
933 * If it is marked as deleted, just skip it.
934 */
935 if (dent->nameext.name[0] == DELETED_FLAG ||
936 dent->nameext.name[0] == aRING)
937 return NULL;
938
939 itr->l_name[n] = '\0';
940
941 chksum = mkcksum(&dent->nameext);
942
943 /* checksum mismatch could mean deleted file, etc.. skip it: */
944 if (chksum != alias_checksum) {
945 debug("** chksum=%x, alias_checksum=%x, l_name=%s, s_name=%8s.%3s\n",
946 chksum, alias_checksum, itr->l_name, dent->nameext.name,
947 dent->nameext.ext);
948 return NULL;
949 }
950
951 return dent;
952 }
953
954 /**
955 * fat_itr_next() - step to the next entry in a directory
956 *
957 * Must be called once on a new iterator before the cursor is valid.
958 *
959 * @itr: the iterator to iterate
960 * @return boolean, 1 if success or 0 if no more entries in the
961 * current directory
962 */
fat_itr_next(fat_itr * itr)963 static int fat_itr_next(fat_itr *itr)
964 {
965 dir_entry *dent;
966
967 itr->name = NULL;
968
969 /*
970 * One logical directory entry consist of following slots:
971 * name[0] Attributes
972 * dent[N - N]: LFN[N - 1] N|0x40 ATTR_VFAT
973 * ...
974 * dent[N - 2]: LFN[1] 2 ATTR_VFAT
975 * dent[N - 1]: LFN[0] 1 ATTR_VFAT
976 * dent[N]: SFN ATTR_ARCH
977 */
978
979 while (1) {
980 dent = next_dent(itr);
981 if (!dent) {
982 itr->dent_start = NULL;
983 return 0;
984 }
985 itr->dent_rem = itr->remaining;
986 itr->dent_start = itr->dent;
987 itr->dent_clust = itr->clust;
988 if (dent->nameext.name[0] == DELETED_FLAG)
989 continue;
990
991 if (dent->attr & ATTR_VOLUME) {
992 if ((dent->attr & ATTR_VFAT) == ATTR_VFAT &&
993 (dent->nameext.name[0] & LAST_LONG_ENTRY_MASK)) {
994 /* long file name */
995 dent = extract_vfat_name(itr);
996 /*
997 * If succeeded, dent has a valid short file
998 * name entry for the current entry.
999 * If failed, itr points to a current bogus
1000 * entry. So after fetching a next one,
1001 * it may have a short file name entry
1002 * for this bogus entry so that we can still
1003 * check for a short name.
1004 */
1005 if (!dent)
1006 continue;
1007 itr->name = itr->l_name;
1008 break;
1009 } else {
1010 /* Volume label or VFAT entry, skip */
1011 continue;
1012 }
1013 }
1014
1015 /* short file name */
1016 break;
1017 }
1018
1019 get_name(dent, itr->s_name);
1020 if (!itr->name)
1021 itr->name = itr->s_name;
1022
1023 return 1;
1024 }
1025
1026 /**
1027 * fat_itr_isdir() - is current cursor position pointing to a directory
1028 *
1029 * @itr: the iterator
1030 * @return true if cursor is at a directory
1031 */
fat_itr_isdir(fat_itr * itr)1032 static int fat_itr_isdir(fat_itr *itr)
1033 {
1034 return !!(itr->dent->attr & ATTR_DIR);
1035 }
1036
1037 /*
1038 * Helpers:
1039 */
1040
1041 #define TYPE_FILE 0x1
1042 #define TYPE_DIR 0x2
1043 #define TYPE_ANY (TYPE_FILE | TYPE_DIR)
1044
1045 /**
1046 * fat_itr_resolve() - traverse directory structure to resolve the
1047 * requested path.
1048 *
1049 * Traverse directory structure to the requested path. If the specified
1050 * path is to a directory, this will descend into the directory and
1051 * leave it iterator at the start of the directory. If the path is to a
1052 * file, it will leave the iterator in the parent directory with current
1053 * cursor at file's entry in the directory.
1054 *
1055 * @itr: iterator initialized to root
1056 * @path: the requested path
1057 * @type: bitmask of allowable file types
1058 * @return 0 on success or -errno
1059 */
fat_itr_resolve(fat_itr * itr,const char * path,unsigned type)1060 static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
1061 {
1062 const char *next;
1063
1064 /* chomp any extra leading slashes: */
1065 while (path[0] && ISDIRDELIM(path[0]))
1066 path++;
1067
1068 /* are we at the end? */
1069 if (strlen(path) == 0) {
1070 if (!(type & TYPE_DIR))
1071 return -ENOENT;
1072 return 0;
1073 }
1074
1075 /* find length of next path entry: */
1076 next = path;
1077 while (next[0] && !ISDIRDELIM(next[0]))
1078 next++;
1079
1080 if (itr->is_root) {
1081 /* root dir doesn't have "." nor ".." */
1082 if ((((next - path) == 1) && !strncmp(path, ".", 1)) ||
1083 (((next - path) == 2) && !strncmp(path, "..", 2))) {
1084 /* point back to itself */
1085 itr->clust = itr->fsdata->root_cluster;
1086 itr->next_clust = itr->fsdata->root_cluster;
1087 itr->start_clust = itr->fsdata->root_cluster;
1088 itr->dent = NULL;
1089 itr->remaining = 0;
1090 itr->last_cluster = 0;
1091
1092 if (next[0] == 0) {
1093 if (type & TYPE_DIR)
1094 return 0;
1095 else
1096 return -ENOENT;
1097 }
1098
1099 return fat_itr_resolve(itr, next, type);
1100 }
1101 }
1102
1103 while (fat_itr_next(itr)) {
1104 int match = 0;
1105 unsigned n = max(strlen(itr->name), (size_t)(next - path));
1106
1107 /* check both long and short name: */
1108 if (!strncasecmp(path, itr->name, n))
1109 match = 1;
1110 else if (itr->name != itr->s_name &&
1111 !strncasecmp(path, itr->s_name, n))
1112 match = 1;
1113
1114 if (!match)
1115 continue;
1116
1117 if (fat_itr_isdir(itr)) {
1118 /* recurse into directory: */
1119 fat_itr_child(itr, itr);
1120 return fat_itr_resolve(itr, next, type);
1121 } else if (next[0]) {
1122 /*
1123 * If next is not empty then we have a case
1124 * like: /path/to/realfile/nonsense
1125 */
1126 debug("bad trailing path: %s\n", next);
1127 return -ENOENT;
1128 } else if (!(type & TYPE_FILE)) {
1129 return -ENOTDIR;
1130 } else {
1131 return 0;
1132 }
1133 }
1134
1135 return -ENOENT;
1136 }
1137
file_fat_detectfs(void)1138 int file_fat_detectfs(void)
1139 {
1140 boot_sector bs;
1141 volume_info volinfo;
1142 int fatsize;
1143 char vol_label[12];
1144
1145 if (cur_dev == NULL) {
1146 printf("No current device\n");
1147 return 1;
1148 }
1149
1150 if (IS_ENABLED(CONFIG_HAVE_BLOCK_DEVICE)) {
1151 printf("Interface: %s\n", blk_get_if_type_name(cur_dev->if_type));
1152 printf(" Device %d: ", cur_dev->devnum);
1153 dev_print(cur_dev);
1154 }
1155
1156 if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1157 printf("\nNo valid FAT fs found\n");
1158 return 1;
1159 }
1160
1161 memcpy(vol_label, volinfo.volume_label, 11);
1162 vol_label[11] = '\0';
1163 volinfo.fs_type[5] = '\0';
1164
1165 printf("Filesystem: %s \"%s\"\n", volinfo.fs_type, vol_label);
1166
1167 return 0;
1168 }
1169
fat_exists(const char * filename)1170 int fat_exists(const char *filename)
1171 {
1172 fsdata fsdata;
1173 fat_itr *itr;
1174 int ret;
1175
1176 itr = malloc_cache_aligned(sizeof(fat_itr));
1177 if (!itr)
1178 return 0;
1179 ret = fat_itr_root(itr, &fsdata);
1180 if (ret)
1181 goto out;
1182
1183 ret = fat_itr_resolve(itr, filename, TYPE_ANY);
1184 free(fsdata.fatbuf);
1185 out:
1186 free(itr);
1187 return ret == 0;
1188 }
1189
fat_size(const char * filename,loff_t * size)1190 int fat_size(const char *filename, loff_t *size)
1191 {
1192 fsdata fsdata;
1193 fat_itr *itr;
1194 int ret;
1195
1196 itr = malloc_cache_aligned(sizeof(fat_itr));
1197 if (!itr)
1198 return -ENOMEM;
1199 ret = fat_itr_root(itr, &fsdata);
1200 if (ret)
1201 goto out_free_itr;
1202
1203 ret = fat_itr_resolve(itr, filename, TYPE_FILE);
1204 if (ret) {
1205 /*
1206 * Directories don't have size, but fs_size() is not
1207 * expected to fail if passed a directory path:
1208 */
1209 free(fsdata.fatbuf);
1210 ret = fat_itr_root(itr, &fsdata);
1211 if (ret)
1212 goto out_free_itr;
1213 ret = fat_itr_resolve(itr, filename, TYPE_DIR);
1214 if (!ret)
1215 *size = 0;
1216 goto out_free_both;
1217 }
1218
1219 *size = FAT2CPU32(itr->dent->size);
1220 out_free_both:
1221 free(fsdata.fatbuf);
1222 out_free_itr:
1223 free(itr);
1224 return ret;
1225 }
1226
file_fat_read_at(const char * filename,loff_t pos,void * buffer,loff_t maxsize,loff_t * actread)1227 int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
1228 loff_t maxsize, loff_t *actread)
1229 {
1230 fsdata fsdata;
1231 fat_itr *itr;
1232 int ret;
1233
1234 itr = malloc_cache_aligned(sizeof(fat_itr));
1235 if (!itr)
1236 return -ENOMEM;
1237 ret = fat_itr_root(itr, &fsdata);
1238 if (ret)
1239 goto out_free_itr;
1240
1241 ret = fat_itr_resolve(itr, filename, TYPE_FILE);
1242 if (ret)
1243 goto out_free_both;
1244
1245 debug("reading %s at pos %llu\n", filename, pos);
1246
1247 /* For saving default max clustersize memory allocated to malloc pool */
1248 dir_entry *dentptr = itr->dent;
1249
1250 ret = get_contents(&fsdata, dentptr, pos, buffer, maxsize, actread);
1251
1252 out_free_both:
1253 free(fsdata.fatbuf);
1254 out_free_itr:
1255 free(itr);
1256 return ret;
1257 }
1258
file_fat_read(const char * filename,void * buffer,int maxsize)1259 int file_fat_read(const char *filename, void *buffer, int maxsize)
1260 {
1261 loff_t actread;
1262 int ret;
1263
1264 ret = file_fat_read_at(filename, 0, buffer, maxsize, &actread);
1265 if (ret)
1266 return ret;
1267 else
1268 return actread;
1269 }
1270
fat_read_file(const char * filename,void * buf,loff_t offset,loff_t len,loff_t * actread)1271 int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
1272 loff_t *actread)
1273 {
1274 int ret;
1275
1276 ret = file_fat_read_at(filename, offset, buf, len, actread);
1277 if (ret)
1278 printf("** Unable to read file %s **\n", filename);
1279
1280 return ret;
1281 }
1282
1283 typedef struct {
1284 struct fs_dir_stream parent;
1285 struct fs_dirent dirent;
1286 fsdata fsdata;
1287 fat_itr itr;
1288 } fat_dir;
1289
fat_opendir(const char * filename,struct fs_dir_stream ** dirsp)1290 int fat_opendir(const char *filename, struct fs_dir_stream **dirsp)
1291 {
1292 fat_dir *dir;
1293 int ret;
1294
1295 dir = malloc_cache_aligned(sizeof(*dir));
1296 if (!dir)
1297 return -ENOMEM;
1298 memset(dir, 0, sizeof(*dir));
1299
1300 ret = fat_itr_root(&dir->itr, &dir->fsdata);
1301 if (ret)
1302 goto fail_free_dir;
1303
1304 ret = fat_itr_resolve(&dir->itr, filename, TYPE_DIR);
1305 if (ret)
1306 goto fail_free_both;
1307
1308 *dirsp = (struct fs_dir_stream *)dir;
1309 return 0;
1310
1311 fail_free_both:
1312 free(dir->fsdata.fatbuf);
1313 fail_free_dir:
1314 free(dir);
1315 return ret;
1316 }
1317
fat_readdir(struct fs_dir_stream * dirs,struct fs_dirent ** dentp)1318 int fat_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp)
1319 {
1320 fat_dir *dir = (fat_dir *)dirs;
1321 struct fs_dirent *dent = &dir->dirent;
1322
1323 if (!fat_itr_next(&dir->itr))
1324 return -ENOENT;
1325
1326 memset(dent, 0, sizeof(*dent));
1327 strcpy(dent->name, dir->itr.name);
1328
1329 if (fat_itr_isdir(&dir->itr)) {
1330 dent->type = FS_DT_DIR;
1331 } else {
1332 dent->type = FS_DT_REG;
1333 dent->size = FAT2CPU32(dir->itr.dent->size);
1334 }
1335
1336 *dentp = dent;
1337
1338 return 0;
1339 }
1340
fat_closedir(struct fs_dir_stream * dirs)1341 void fat_closedir(struct fs_dir_stream *dirs)
1342 {
1343 fat_dir *dir = (fat_dir *)dirs;
1344 free(dir->fsdata.fatbuf);
1345 free(dir);
1346 }
1347
fat_close(void)1348 void fat_close(void)
1349 {
1350 }
1351
fat_uuid(char * uuid_str)1352 int fat_uuid(char *uuid_str)
1353 {
1354 boot_sector bs;
1355 volume_info volinfo;
1356 int fatsize;
1357 int ret;
1358 u8 *id;
1359
1360 ret = read_bootsectandvi(&bs, &volinfo, &fatsize);
1361 if (ret)
1362 return ret;
1363
1364 id = volinfo.volume_id;
1365 sprintf(uuid_str, "%02X%02X-%02X%02X", id[3], id[2], id[1], id[0]);
1366
1367 return 0;
1368 }
1369