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->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->ext[0] && dirent->ext[0] != ' ') {
134 *ptr++ = '.';
135 memcpy(ptr, dirent->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 idx = 0;
252 __u32 startsect;
253 int ret;
254
255 if (clustnum > 0) {
256 startsect = clust_to_sect(mydata, clustnum);
257 } else {
258 startsect = mydata->rootdir_sect;
259 }
260
261 debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
262
263 if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
264 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
265
266 debug("FAT: Misaligned buffer address (%p)\n", buffer);
267
268 while (size >= mydata->sect_size) {
269 ret = disk_read(startsect++, 1, tmpbuf);
270 if (ret != 1) {
271 debug("Error reading data (got %d)\n", ret);
272 return -1;
273 }
274
275 memcpy(buffer, tmpbuf, mydata->sect_size);
276 buffer += mydata->sect_size;
277 size -= mydata->sect_size;
278 }
279 } else {
280 idx = size / mydata->sect_size;
281 ret = disk_read(startsect, idx, buffer);
282 if (ret != idx) {
283 debug("Error reading data (got %d)\n", ret);
284 return -1;
285 }
286 startsect += idx;
287 idx *= mydata->sect_size;
288 buffer += idx;
289 size -= idx;
290 }
291 if (size) {
292 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
293
294 ret = disk_read(startsect, 1, tmpbuf);
295 if (ret != 1) {
296 debug("Error reading data (got %d)\n", ret);
297 return -1;
298 }
299
300 memcpy(buffer, tmpbuf, size);
301 }
302
303 return 0;
304 }
305
306 /**
307 * get_contents() - read from file
308 *
309 * Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
310 * into 'buffer'. Update the number of bytes read in *gotsize or return -1 on
311 * fatal errors.
312 *
313 * @mydata: file system description
314 * @dentprt: directory entry pointer
315 * @pos: position from where to read
316 * @buffer: buffer into which to read
317 * @maxsize: maximum number of bytes to read
318 * @gotsize: number of bytes actually read
319 * Return: -1 on error, otherwise 0
320 */
get_contents(fsdata * mydata,dir_entry * dentptr,loff_t pos,__u8 * buffer,loff_t maxsize,loff_t * gotsize)321 static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
322 __u8 *buffer, loff_t maxsize, loff_t *gotsize)
323 {
324 loff_t filesize = FAT2CPU32(dentptr->size);
325 unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
326 __u32 curclust = START(dentptr);
327 __u32 endclust, newclust;
328 loff_t actsize;
329
330 *gotsize = 0;
331 debug("Filesize: %llu bytes\n", filesize);
332
333 if (pos >= filesize) {
334 debug("Read position past EOF: %llu\n", pos);
335 return 0;
336 }
337
338 if (maxsize > 0 && filesize > pos + maxsize)
339 filesize = pos + maxsize;
340
341 debug("%llu bytes\n", filesize);
342
343 actsize = bytesperclust;
344
345 /* go to cluster at pos */
346 while (actsize <= pos) {
347 curclust = get_fatent(mydata, curclust);
348 if (CHECK_CLUST(curclust, mydata->fatsize)) {
349 debug("curclust: 0x%x\n", curclust);
350 printf("Invalid FAT entry\n");
351 return -1;
352 }
353 actsize += bytesperclust;
354 }
355
356 /* actsize > pos */
357 actsize -= bytesperclust;
358 filesize -= actsize;
359 pos -= actsize;
360
361 /* align to beginning of next cluster if any */
362 if (pos) {
363 __u8 *tmp_buffer;
364
365 actsize = min(filesize, (loff_t)bytesperclust);
366 tmp_buffer = malloc_cache_aligned(actsize);
367 if (!tmp_buffer) {
368 debug("Error: allocating buffer\n");
369 return -1;
370 }
371
372 if (get_cluster(mydata, curclust, tmp_buffer, actsize) != 0) {
373 printf("Error reading cluster\n");
374 free(tmp_buffer);
375 return -1;
376 }
377 filesize -= actsize;
378 actsize -= pos;
379 memcpy(buffer, tmp_buffer + pos, actsize);
380 free(tmp_buffer);
381 *gotsize += actsize;
382 if (!filesize)
383 return 0;
384 buffer += actsize;
385
386 curclust = get_fatent(mydata, curclust);
387 if (CHECK_CLUST(curclust, mydata->fatsize)) {
388 debug("curclust: 0x%x\n", curclust);
389 printf("Invalid FAT entry\n");
390 return -1;
391 }
392 }
393
394 actsize = bytesperclust;
395 endclust = curclust;
396
397 do {
398 /* search for consecutive clusters */
399 while (actsize < filesize) {
400 newclust = get_fatent(mydata, endclust);
401 if ((newclust - 1) != endclust)
402 goto getit;
403 if (CHECK_CLUST(newclust, mydata->fatsize)) {
404 debug("curclust: 0x%x\n", newclust);
405 printf("Invalid FAT entry\n");
406 return -1;
407 }
408 endclust = newclust;
409 actsize += bytesperclust;
410 }
411
412 /* get remaining bytes */
413 actsize = filesize;
414 if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
415 printf("Error reading cluster\n");
416 return -1;
417 }
418 *gotsize += actsize;
419 return 0;
420 getit:
421 if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
422 printf("Error reading cluster\n");
423 return -1;
424 }
425 *gotsize += (int)actsize;
426 filesize -= actsize;
427 buffer += actsize;
428
429 curclust = get_fatent(mydata, endclust);
430 if (CHECK_CLUST(curclust, mydata->fatsize)) {
431 debug("curclust: 0x%x\n", curclust);
432 printf("Invalid FAT entry\n");
433 return -1;
434 }
435 actsize = bytesperclust;
436 endclust = curclust;
437 } while (1);
438 }
439
440 /*
441 * Extract the file name information from 'slotptr' into 'l_name',
442 * starting at l_name[*idx].
443 * Return 1 if terminator (zero byte) is found, 0 otherwise.
444 */
slot2str(dir_slot * slotptr,char * l_name,int * idx)445 static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
446 {
447 int j;
448
449 for (j = 0; j <= 8; j += 2) {
450 l_name[*idx] = slotptr->name0_4[j];
451 if (l_name[*idx] == 0x00)
452 return 1;
453 (*idx)++;
454 }
455 for (j = 0; j <= 10; j += 2) {
456 l_name[*idx] = slotptr->name5_10[j];
457 if (l_name[*idx] == 0x00)
458 return 1;
459 (*idx)++;
460 }
461 for (j = 0; j <= 2; j += 2) {
462 l_name[*idx] = slotptr->name11_12[j];
463 if (l_name[*idx] == 0x00)
464 return 1;
465 (*idx)++;
466 }
467
468 return 0;
469 }
470
471 /* Calculate short name checksum */
mkcksum(const char name[8],const char ext[3])472 static __u8 mkcksum(const char name[8], const char ext[3])
473 {
474 int i;
475
476 __u8 ret = 0;
477
478 for (i = 0; i < 8; i++)
479 ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
480 for (i = 0; i < 3; i++)
481 ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
482
483 return ret;
484 }
485
486 /*
487 * Read boot sector and volume info from a FAT filesystem
488 */
489 static int
read_bootsectandvi(boot_sector * bs,volume_info * volinfo,int * fatsize)490 read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
491 {
492 __u8 *block;
493 volume_info *vistart;
494 int ret = 0;
495
496 if (cur_dev == NULL) {
497 debug("Error: no device selected\n");
498 return -1;
499 }
500
501 block = malloc_cache_aligned(cur_dev->blksz);
502 if (block == NULL) {
503 debug("Error: allocating block\n");
504 return -1;
505 }
506
507 if (disk_read(0, 1, block) < 0) {
508 debug("Error: reading block\n");
509 goto fail;
510 }
511
512 memcpy(bs, block, sizeof(boot_sector));
513 bs->reserved = FAT2CPU16(bs->reserved);
514 bs->fat_length = FAT2CPU16(bs->fat_length);
515 bs->secs_track = FAT2CPU16(bs->secs_track);
516 bs->heads = FAT2CPU16(bs->heads);
517 bs->total_sect = FAT2CPU32(bs->total_sect);
518
519 /* FAT32 entries */
520 if (bs->fat_length == 0) {
521 /* Assume FAT32 */
522 bs->fat32_length = FAT2CPU32(bs->fat32_length);
523 bs->flags = FAT2CPU16(bs->flags);
524 bs->root_cluster = FAT2CPU32(bs->root_cluster);
525 bs->info_sector = FAT2CPU16(bs->info_sector);
526 bs->backup_boot = FAT2CPU16(bs->backup_boot);
527 vistart = (volume_info *)(block + sizeof(boot_sector));
528 *fatsize = 32;
529 } else {
530 vistart = (volume_info *)&(bs->fat32_length);
531 *fatsize = 0;
532 }
533 memcpy(volinfo, vistart, sizeof(volume_info));
534
535 if (*fatsize == 32) {
536 if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
537 goto exit;
538 } else {
539 if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
540 *fatsize = 12;
541 goto exit;
542 }
543 if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
544 *fatsize = 16;
545 goto exit;
546 }
547 }
548
549 debug("Error: broken fs_type sign\n");
550 fail:
551 ret = -1;
552 exit:
553 free(block);
554 return ret;
555 }
556
get_fs_info(fsdata * mydata)557 static int get_fs_info(fsdata *mydata)
558 {
559 boot_sector bs;
560 volume_info volinfo;
561 int ret;
562
563 ret = read_bootsectandvi(&bs, &volinfo, &mydata->fatsize);
564 if (ret) {
565 debug("Error: reading boot sector\n");
566 return ret;
567 }
568
569 if (mydata->fatsize == 32) {
570 mydata->fatlength = bs.fat32_length;
571 mydata->total_sect = bs.total_sect;
572 } else {
573 mydata->fatlength = bs.fat_length;
574 mydata->total_sect = (bs.sectors[1] << 8) + bs.sectors[0];
575 if (!mydata->total_sect)
576 mydata->total_sect = bs.total_sect;
577 }
578 if (!mydata->total_sect) /* unlikely */
579 mydata->total_sect = (u32)cur_part_info.size;
580
581 mydata->fats = bs.fats;
582 mydata->fat_sect = bs.reserved;
583
584 mydata->rootdir_sect = mydata->fat_sect + mydata->fatlength * bs.fats;
585
586 mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
587 mydata->clust_size = bs.cluster_size;
588 if (mydata->sect_size != cur_part_info.blksz) {
589 printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
590 mydata->sect_size, cur_part_info.blksz);
591 return -1;
592 }
593 if (mydata->clust_size == 0) {
594 printf("Error: FAT cluster size not set\n");
595 return -1;
596 }
597 if ((unsigned int)mydata->clust_size * mydata->sect_size >
598 MAX_CLUSTSIZE) {
599 printf("Error: FAT cluster size too big (cs=%u, max=%u)\n",
600 (unsigned int)mydata->clust_size * mydata->sect_size,
601 MAX_CLUSTSIZE);
602 return -1;
603 }
604
605 if (mydata->fatsize == 32) {
606 mydata->data_begin = mydata->rootdir_sect -
607 (mydata->clust_size * 2);
608 mydata->root_cluster = bs.root_cluster;
609 } else {
610 mydata->rootdir_size = ((bs.dir_entries[1] * (int)256 +
611 bs.dir_entries[0]) *
612 sizeof(dir_entry)) /
613 mydata->sect_size;
614 mydata->data_begin = mydata->rootdir_sect +
615 mydata->rootdir_size -
616 (mydata->clust_size * 2);
617
618 /*
619 * The root directory is not cluster-aligned and may be on a
620 * "negative" cluster, this will be handled specially in
621 * next_cluster().
622 */
623 mydata->root_cluster = 0;
624 }
625
626 mydata->fatbufnum = -1;
627 mydata->fat_dirty = 0;
628 mydata->fatbuf = malloc_cache_aligned(FATBUFSIZE);
629 if (mydata->fatbuf == NULL) {
630 debug("Error: allocating memory\n");
631 return -1;
632 }
633
634 debug("FAT%d, fat_sect: %d, fatlength: %d\n",
635 mydata->fatsize, mydata->fat_sect, mydata->fatlength);
636 debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
637 "Data begins at: %d\n",
638 mydata->root_cluster,
639 mydata->rootdir_sect,
640 mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
641 debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
642 mydata->clust_size);
643
644 return 0;
645 }
646
647
648 /*
649 * Directory iterator, to simplify filesystem traversal
650 *
651 * Implements an iterator pattern to traverse directory tables,
652 * transparently handling directory tables split across multiple
653 * clusters, and the difference between FAT12/FAT16 root directory
654 * (contiguous) and subdirectories + FAT32 root (chained).
655 *
656 * Rough usage:
657 *
658 * for (fat_itr_root(&itr, fsdata); fat_itr_next(&itr); ) {
659 * // to traverse down to a subdirectory pointed to by
660 * // current iterator position:
661 * fat_itr_child(&itr, &itr);
662 * }
663 *
664 * For more complete example, see fat_itr_resolve()
665 */
666
667 typedef struct {
668 fsdata *fsdata; /* filesystem parameters */
669 unsigned start_clust; /* first cluster */
670 unsigned clust; /* current cluster */
671 unsigned next_clust; /* next cluster if remaining == 0 */
672 int last_cluster; /* set once we've read last cluster */
673 int is_root; /* is iterator at root directory */
674 int remaining; /* remaining dent's in current cluster */
675
676 /* current iterator position values: */
677 dir_entry *dent; /* current directory entry */
678 char l_name[VFAT_MAXLEN_BYTES]; /* long (vfat) name */
679 char s_name[14]; /* short 8.3 name */
680 char *name; /* l_name if there is one, else s_name */
681
682 /* storage for current cluster in memory: */
683 u8 block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
684 } fat_itr;
685
686 static int fat_itr_isdir(fat_itr *itr);
687
688 /**
689 * fat_itr_root() - initialize an iterator to start at the root
690 * directory
691 *
692 * @itr: iterator to initialize
693 * @fsdata: filesystem data for the partition
694 * @return 0 on success, else -errno
695 */
fat_itr_root(fat_itr * itr,fsdata * fsdata)696 static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
697 {
698 if (get_fs_info(fsdata))
699 return -ENXIO;
700
701 itr->fsdata = fsdata;
702 itr->start_clust = 0;
703 itr->clust = fsdata->root_cluster;
704 itr->next_clust = fsdata->root_cluster;
705 itr->dent = NULL;
706 itr->remaining = 0;
707 itr->last_cluster = 0;
708 itr->is_root = 1;
709
710 return 0;
711 }
712
713 /**
714 * fat_itr_child() - initialize an iterator to descend into a sub-
715 * directory
716 *
717 * Initializes 'itr' to iterate the contents of the directory at
718 * the current cursor position of 'parent'. It is an error to
719 * call this if the current cursor of 'parent' is pointing at a
720 * regular file.
721 *
722 * Note that 'itr' and 'parent' can be the same pointer if you do
723 * not need to preserve 'parent' after this call, which is useful
724 * for traversing directory structure to resolve a file/directory.
725 *
726 * @itr: iterator to initialize
727 * @parent: the iterator pointing at a directory entry in the
728 * parent directory of the directory to iterate
729 */
fat_itr_child(fat_itr * itr,fat_itr * parent)730 static void fat_itr_child(fat_itr *itr, fat_itr *parent)
731 {
732 fsdata *mydata = parent->fsdata; /* for silly macros */
733 unsigned clustnum = START(parent->dent);
734
735 assert(fat_itr_isdir(parent));
736
737 itr->fsdata = parent->fsdata;
738 itr->start_clust = clustnum;
739 if (clustnum > 0) {
740 itr->clust = clustnum;
741 itr->next_clust = clustnum;
742 itr->is_root = 0;
743 } else {
744 itr->clust = parent->fsdata->root_cluster;
745 itr->next_clust = parent->fsdata->root_cluster;
746 itr->is_root = 1;
747 }
748 itr->dent = NULL;
749 itr->remaining = 0;
750 itr->last_cluster = 0;
751 }
752
next_cluster(fat_itr * itr,unsigned * nbytes)753 static void *next_cluster(fat_itr *itr, unsigned *nbytes)
754 {
755 fsdata *mydata = itr->fsdata; /* for silly macros */
756 int ret;
757 u32 sect;
758 u32 read_size;
759
760 /* have we reached the end? */
761 if (itr->last_cluster)
762 return NULL;
763
764 if (itr->is_root && itr->fsdata->fatsize != 32) {
765 /*
766 * The root directory is located before the data area and
767 * cannot be indexed using the regular unsigned cluster
768 * numbers (it may start at a "negative" cluster or not at a
769 * cluster boundary at all), so consider itr->next_clust to be
770 * a offset in cluster-sized units from the start of rootdir.
771 */
772 unsigned sect_offset = itr->next_clust * itr->fsdata->clust_size;
773 unsigned remaining_sects = itr->fsdata->rootdir_size - sect_offset;
774 sect = itr->fsdata->rootdir_sect + sect_offset;
775 /* do not read past the end of rootdir */
776 read_size = min_t(u32, itr->fsdata->clust_size,
777 remaining_sects);
778 } else {
779 sect = clust_to_sect(itr->fsdata, itr->next_clust);
780 read_size = itr->fsdata->clust_size;
781 }
782
783 debug("FAT read(sect=%d), clust_size=%d, read_size=%u, DIRENTSPERBLOCK=%zd\n",
784 sect, itr->fsdata->clust_size, read_size, DIRENTSPERBLOCK);
785
786 /*
787 * NOTE: do_fat_read_at() had complicated logic to deal w/
788 * vfat names that span multiple clusters in the fat16 case,
789 * which get_dentfromdir() probably also needed (and was
790 * missing). And not entirely sure what fat32 didn't have
791 * the same issue.. We solve that by only caring about one
792 * dent at a time and iteratively constructing the vfat long
793 * name.
794 */
795 ret = disk_read(sect, read_size, itr->block);
796 if (ret < 0) {
797 debug("Error: reading block\n");
798 return NULL;
799 }
800
801 *nbytes = read_size * itr->fsdata->sect_size;
802 itr->clust = itr->next_clust;
803 if (itr->is_root && itr->fsdata->fatsize != 32) {
804 itr->next_clust++;
805 if (itr->next_clust * itr->fsdata->clust_size >=
806 itr->fsdata->rootdir_size) {
807 debug("nextclust: 0x%x\n", itr->next_clust);
808 itr->last_cluster = 1;
809 }
810 } else {
811 itr->next_clust = get_fatent(itr->fsdata, itr->next_clust);
812 if (CHECK_CLUST(itr->next_clust, itr->fsdata->fatsize)) {
813 debug("nextclust: 0x%x\n", itr->next_clust);
814 itr->last_cluster = 1;
815 }
816 }
817
818 return itr->block;
819 }
820
next_dent(fat_itr * itr)821 static dir_entry *next_dent(fat_itr *itr)
822 {
823 if (itr->remaining == 0) {
824 unsigned nbytes;
825 struct dir_entry *dent = next_cluster(itr, &nbytes);
826
827 /* have we reached the last cluster? */
828 if (!dent) {
829 /* a sign for no more entries left */
830 itr->dent = NULL;
831 return NULL;
832 }
833
834 itr->remaining = nbytes / sizeof(dir_entry) - 1;
835 itr->dent = dent;
836 } else {
837 itr->remaining--;
838 itr->dent++;
839 }
840
841 /* have we reached the last valid entry? */
842 if (itr->dent->name[0] == 0)
843 return NULL;
844
845 return itr->dent;
846 }
847
extract_vfat_name(fat_itr * itr)848 static dir_entry *extract_vfat_name(fat_itr *itr)
849 {
850 struct dir_entry *dent = itr->dent;
851 int seqn = itr->dent->name[0] & ~LAST_LONG_ENTRY_MASK;
852 u8 chksum, alias_checksum = ((dir_slot *)dent)->alias_checksum;
853 int n = 0;
854
855 while (seqn--) {
856 char buf[13];
857 int idx = 0;
858
859 slot2str((dir_slot *)dent, buf, &idx);
860
861 if (n + idx >= sizeof(itr->l_name))
862 return NULL;
863
864 /* shift accumulated long-name up and copy new part in: */
865 memmove(itr->l_name + idx, itr->l_name, n);
866 memcpy(itr->l_name, buf, idx);
867 n += idx;
868
869 dent = next_dent(itr);
870 if (!dent)
871 return NULL;
872 }
873
874 /*
875 * We are now at the short file name entry.
876 * If it is marked as deleted, just skip it.
877 */
878 if (dent->name[0] == DELETED_FLAG ||
879 dent->name[0] == aRING)
880 return NULL;
881
882 itr->l_name[n] = '\0';
883
884 chksum = mkcksum(dent->name, dent->ext);
885
886 /* checksum mismatch could mean deleted file, etc.. skip it: */
887 if (chksum != alias_checksum) {
888 debug("** chksum=%x, alias_checksum=%x, l_name=%s, s_name=%8s.%3s\n",
889 chksum, alias_checksum, itr->l_name, dent->name, dent->ext);
890 return NULL;
891 }
892
893 return dent;
894 }
895
896 /**
897 * fat_itr_next() - step to the next entry in a directory
898 *
899 * Must be called once on a new iterator before the cursor is valid.
900 *
901 * @itr: the iterator to iterate
902 * @return boolean, 1 if success or 0 if no more entries in the
903 * current directory
904 */
fat_itr_next(fat_itr * itr)905 static int fat_itr_next(fat_itr *itr)
906 {
907 dir_entry *dent;
908
909 itr->name = NULL;
910
911 /*
912 * One logical directory entry consist of following slots:
913 * name[0] Attributes
914 * dent[N - N]: LFN[N - 1] N|0x40 ATTR_VFAT
915 * ...
916 * dent[N - 2]: LFN[1] 2 ATTR_VFAT
917 * dent[N - 1]: LFN[0] 1 ATTR_VFAT
918 * dent[N]: SFN ATTR_ARCH
919 */
920
921 while (1) {
922 dent = next_dent(itr);
923 if (!dent)
924 return 0;
925
926 if (dent->name[0] == DELETED_FLAG ||
927 dent->name[0] == aRING)
928 continue;
929
930 if (dent->attr & ATTR_VOLUME) {
931 if ((dent->attr & ATTR_VFAT) == ATTR_VFAT &&
932 (dent->name[0] & LAST_LONG_ENTRY_MASK)) {
933 /* long file name */
934 dent = extract_vfat_name(itr);
935 /*
936 * If succeeded, dent has a valid short file
937 * name entry for the current entry.
938 * If failed, itr points to a current bogus
939 * entry. So after fetching a next one,
940 * it may have a short file name entry
941 * for this bogus entry so that we can still
942 * check for a short name.
943 */
944 if (!dent)
945 continue;
946 itr->name = itr->l_name;
947 break;
948 } else {
949 /* Volume label or VFAT entry, skip */
950 continue;
951 }
952 } else if (!(dent->attr & ATTR_ARCH) &&
953 !(dent->attr & ATTR_DIR))
954 continue;
955
956 /* short file name */
957 break;
958 }
959
960 get_name(dent, itr->s_name);
961 if (!itr->name)
962 itr->name = itr->s_name;
963
964 return 1;
965 }
966
967 /**
968 * fat_itr_isdir() - is current cursor position pointing to a directory
969 *
970 * @itr: the iterator
971 * @return true if cursor is at a directory
972 */
fat_itr_isdir(fat_itr * itr)973 static int fat_itr_isdir(fat_itr *itr)
974 {
975 return !!(itr->dent->attr & ATTR_DIR);
976 }
977
978 /*
979 * Helpers:
980 */
981
982 #define TYPE_FILE 0x1
983 #define TYPE_DIR 0x2
984 #define TYPE_ANY (TYPE_FILE | TYPE_DIR)
985
986 /**
987 * fat_itr_resolve() - traverse directory structure to resolve the
988 * requested path.
989 *
990 * Traverse directory structure to the requested path. If the specified
991 * path is to a directory, this will descend into the directory and
992 * leave it iterator at the start of the directory. If the path is to a
993 * file, it will leave the iterator in the parent directory with current
994 * cursor at file's entry in the directory.
995 *
996 * @itr: iterator initialized to root
997 * @path: the requested path
998 * @type: bitmask of allowable file types
999 * @return 0 on success or -errno
1000 */
fat_itr_resolve(fat_itr * itr,const char * path,unsigned type)1001 static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
1002 {
1003 const char *next;
1004
1005 /* chomp any extra leading slashes: */
1006 while (path[0] && ISDIRDELIM(path[0]))
1007 path++;
1008
1009 /* are we at the end? */
1010 if (strlen(path) == 0) {
1011 if (!(type & TYPE_DIR))
1012 return -ENOENT;
1013 return 0;
1014 }
1015
1016 /* find length of next path entry: */
1017 next = path;
1018 while (next[0] && !ISDIRDELIM(next[0]))
1019 next++;
1020
1021 if (itr->is_root) {
1022 /* root dir doesn't have "." nor ".." */
1023 if ((((next - path) == 1) && !strncmp(path, ".", 1)) ||
1024 (((next - path) == 2) && !strncmp(path, "..", 2))) {
1025 /* point back to itself */
1026 itr->clust = itr->fsdata->root_cluster;
1027 itr->next_clust = itr->fsdata->root_cluster;
1028 itr->dent = NULL;
1029 itr->remaining = 0;
1030 itr->last_cluster = 0;
1031
1032 if (next[0] == 0) {
1033 if (type & TYPE_DIR)
1034 return 0;
1035 else
1036 return -ENOENT;
1037 }
1038
1039 return fat_itr_resolve(itr, next, type);
1040 }
1041 }
1042
1043 while (fat_itr_next(itr)) {
1044 int match = 0;
1045 unsigned n = max(strlen(itr->name), (size_t)(next - path));
1046
1047 /* check both long and short name: */
1048 if (!strncasecmp(path, itr->name, n))
1049 match = 1;
1050 else if (itr->name != itr->s_name &&
1051 !strncasecmp(path, itr->s_name, n))
1052 match = 1;
1053
1054 if (!match)
1055 continue;
1056
1057 if (fat_itr_isdir(itr)) {
1058 /* recurse into directory: */
1059 fat_itr_child(itr, itr);
1060 return fat_itr_resolve(itr, next, type);
1061 } else if (next[0]) {
1062 /*
1063 * If next is not empty then we have a case
1064 * like: /path/to/realfile/nonsense
1065 */
1066 debug("bad trailing path: %s\n", next);
1067 return -ENOENT;
1068 } else if (!(type & TYPE_FILE)) {
1069 return -ENOTDIR;
1070 } else {
1071 return 0;
1072 }
1073 }
1074
1075 return -ENOENT;
1076 }
1077
file_fat_detectfs(void)1078 int file_fat_detectfs(void)
1079 {
1080 boot_sector bs;
1081 volume_info volinfo;
1082 int fatsize;
1083 char vol_label[12];
1084
1085 if (cur_dev == NULL) {
1086 printf("No current device\n");
1087 return 1;
1088 }
1089
1090 #if defined(CONFIG_IDE) || \
1091 defined(CONFIG_SATA) || \
1092 defined(CONFIG_SCSI) || \
1093 defined(CONFIG_CMD_USB) || \
1094 defined(CONFIG_MMC)
1095 printf("Interface: ");
1096 switch (cur_dev->if_type) {
1097 case IF_TYPE_IDE:
1098 printf("IDE");
1099 break;
1100 case IF_TYPE_SATA:
1101 printf("SATA");
1102 break;
1103 case IF_TYPE_SCSI:
1104 printf("SCSI");
1105 break;
1106 case IF_TYPE_ATAPI:
1107 printf("ATAPI");
1108 break;
1109 case IF_TYPE_USB:
1110 printf("USB");
1111 break;
1112 case IF_TYPE_DOC:
1113 printf("DOC");
1114 break;
1115 case IF_TYPE_MMC:
1116 printf("MMC");
1117 break;
1118 default:
1119 printf("Unknown");
1120 }
1121
1122 printf("\n Device %d: ", cur_dev->devnum);
1123 dev_print(cur_dev);
1124 #endif
1125
1126 if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1127 printf("\nNo valid FAT fs found\n");
1128 return 1;
1129 }
1130
1131 memcpy(vol_label, volinfo.volume_label, 11);
1132 vol_label[11] = '\0';
1133 volinfo.fs_type[5] = '\0';
1134
1135 printf("Filesystem: %s \"%s\"\n", volinfo.fs_type, vol_label);
1136
1137 return 0;
1138 }
1139
fat_exists(const char * filename)1140 int fat_exists(const char *filename)
1141 {
1142 fsdata fsdata;
1143 fat_itr *itr;
1144 int ret;
1145
1146 itr = malloc_cache_aligned(sizeof(fat_itr));
1147 if (!itr)
1148 return 0;
1149 ret = fat_itr_root(itr, &fsdata);
1150 if (ret)
1151 goto out;
1152
1153 ret = fat_itr_resolve(itr, filename, TYPE_ANY);
1154 free(fsdata.fatbuf);
1155 out:
1156 free(itr);
1157 return ret == 0;
1158 }
1159
fat_size(const char * filename,loff_t * size)1160 int fat_size(const char *filename, loff_t *size)
1161 {
1162 fsdata fsdata;
1163 fat_itr *itr;
1164 int ret;
1165
1166 itr = malloc_cache_aligned(sizeof(fat_itr));
1167 if (!itr)
1168 return -ENOMEM;
1169 ret = fat_itr_root(itr, &fsdata);
1170 if (ret)
1171 goto out_free_itr;
1172
1173 ret = fat_itr_resolve(itr, filename, TYPE_FILE);
1174 if (ret) {
1175 /*
1176 * Directories don't have size, but fs_size() is not
1177 * expected to fail if passed a directory path:
1178 */
1179 free(fsdata.fatbuf);
1180 ret = fat_itr_root(itr, &fsdata);
1181 if (ret)
1182 goto out_free_itr;
1183 ret = fat_itr_resolve(itr, filename, TYPE_DIR);
1184 if (!ret)
1185 *size = 0;
1186 goto out_free_both;
1187 }
1188
1189 *size = FAT2CPU32(itr->dent->size);
1190 out_free_both:
1191 free(fsdata.fatbuf);
1192 out_free_itr:
1193 free(itr);
1194 return ret;
1195 }
1196
file_fat_read_at(const char * filename,loff_t pos,void * buffer,loff_t maxsize,loff_t * actread)1197 int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
1198 loff_t maxsize, loff_t *actread)
1199 {
1200 fsdata fsdata;
1201 fat_itr *itr;
1202 int ret;
1203
1204 itr = malloc_cache_aligned(sizeof(fat_itr));
1205 if (!itr)
1206 return -ENOMEM;
1207 ret = fat_itr_root(itr, &fsdata);
1208 if (ret)
1209 goto out_free_itr;
1210
1211 ret = fat_itr_resolve(itr, filename, TYPE_FILE);
1212 if (ret)
1213 goto out_free_both;
1214
1215 debug("reading %s at pos %llu\n", filename, pos);
1216
1217 /* For saving default max clustersize memory allocated to malloc pool */
1218 dir_entry *dentptr = itr->dent;
1219
1220 ret = get_contents(&fsdata, dentptr, pos, buffer, maxsize, actread);
1221
1222 out_free_both:
1223 free(fsdata.fatbuf);
1224 out_free_itr:
1225 free(itr);
1226 return ret;
1227 }
1228
file_fat_read(const char * filename,void * buffer,int maxsize)1229 int file_fat_read(const char *filename, void *buffer, int maxsize)
1230 {
1231 loff_t actread;
1232 int ret;
1233
1234 ret = file_fat_read_at(filename, 0, buffer, maxsize, &actread);
1235 if (ret)
1236 return ret;
1237 else
1238 return actread;
1239 }
1240
fat_read_file(const char * filename,void * buf,loff_t offset,loff_t len,loff_t * actread)1241 int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
1242 loff_t *actread)
1243 {
1244 int ret;
1245
1246 ret = file_fat_read_at(filename, offset, buf, len, actread);
1247 if (ret)
1248 printf("** Unable to read file %s **\n", filename);
1249
1250 return ret;
1251 }
1252
1253 typedef struct {
1254 struct fs_dir_stream parent;
1255 struct fs_dirent dirent;
1256 fsdata fsdata;
1257 fat_itr itr;
1258 } fat_dir;
1259
fat_opendir(const char * filename,struct fs_dir_stream ** dirsp)1260 int fat_opendir(const char *filename, struct fs_dir_stream **dirsp)
1261 {
1262 fat_dir *dir;
1263 int ret;
1264
1265 dir = malloc_cache_aligned(sizeof(*dir));
1266 if (!dir)
1267 return -ENOMEM;
1268 memset(dir, 0, sizeof(*dir));
1269
1270 ret = fat_itr_root(&dir->itr, &dir->fsdata);
1271 if (ret)
1272 goto fail_free_dir;
1273
1274 ret = fat_itr_resolve(&dir->itr, filename, TYPE_DIR);
1275 if (ret)
1276 goto fail_free_both;
1277
1278 *dirsp = (struct fs_dir_stream *)dir;
1279 return 0;
1280
1281 fail_free_both:
1282 free(dir->fsdata.fatbuf);
1283 fail_free_dir:
1284 free(dir);
1285 return ret;
1286 }
1287
fat_readdir(struct fs_dir_stream * dirs,struct fs_dirent ** dentp)1288 int fat_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp)
1289 {
1290 fat_dir *dir = (fat_dir *)dirs;
1291 struct fs_dirent *dent = &dir->dirent;
1292
1293 if (!fat_itr_next(&dir->itr))
1294 return -ENOENT;
1295
1296 memset(dent, 0, sizeof(*dent));
1297 strcpy(dent->name, dir->itr.name);
1298
1299 if (fat_itr_isdir(&dir->itr)) {
1300 dent->type = FS_DT_DIR;
1301 } else {
1302 dent->type = FS_DT_REG;
1303 dent->size = FAT2CPU32(dir->itr.dent->size);
1304 }
1305
1306 *dentp = dent;
1307
1308 return 0;
1309 }
1310
fat_closedir(struct fs_dir_stream * dirs)1311 void fat_closedir(struct fs_dir_stream *dirs)
1312 {
1313 fat_dir *dir = (fat_dir *)dirs;
1314 free(dir->fsdata.fatbuf);
1315 free(dir);
1316 }
1317
fat_close(void)1318 void fat_close(void)
1319 {
1320 }
1321