fs/fat/fat.c

   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 <asm/byteorder.h>
  18 #include <part.h>
  19 #include <malloc.h>
  20 #include <memalign.h>
  21 #include <linux/compiler.h>
  22 #include <linux/ctype.h>
  23
  24 /*
  25  * Convert a string to lowercase.  Converts at most 'len' characters,
  26  * 'len' may be larger than the length of 'str' if 'str' is NULL
  27  * terminated.
  28  */
  29 static void downcase(char *str, size_t len)
  30 {
  31         while (*str != '\0' && len--) {
  32                 *str = tolower(*str);
  33                 str++;
  34         }
  35 }
  36
  37 static struct blk_desc *cur_dev;
  38 static disk_partition_t cur_part_info;
  39
  40 #define DOS_BOOT_MAGIC_OFFSET   0x1fe
  41 #define DOS_FS_TYPE_OFFSET      0x36
  42 #define DOS_FS32_TYPE_OFFSET    0x52
  43
  44 static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
  45 {
  46         ulong ret;
  47
  48         if (!cur_dev)
  49                 return -1;
  50
  51         ret = blk_dread(cur_dev, cur_part_info.start + block, nr_blocks, buf);
  52
  53         if (ret != nr_blocks)
  54                 return -1;
  55
  56         return ret;
  57 }
  58
  59 int fat_set_blk_dev(struct blk_desc *dev_desc, disk_partition_t *info)
  60 {
  61         ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
  62
  63         cur_dev = dev_desc;
  64         cur_part_info = *info;
  65
  66         /* Make sure it has a valid FAT header */
  67         if (disk_read(0, 1, buffer) != 1) {
  68                 cur_dev = NULL;
  69                 return -1;
  70         }
  71
  72         /* Check if it's actually a DOS volume */
  73         if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
  74                 cur_dev = NULL;
  75                 return -1;
  76         }
  77
  78         /* Check for FAT12/FAT16/FAT32 filesystem */
  79         if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
  80                 return 0;
  81         if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
  82                 return 0;
  83
  84         cur_dev = NULL;
  85         return -1;
  86 }
  87
  88 int fat_register_device(struct blk_desc *dev_desc, int part_no)
  89 {
  90         disk_partition_t info;
  91
  92         /* First close any currently found FAT filesystem */
  93         cur_dev = NULL;
  94
  95         /* Read the partition table, if present */
  96         if (part_get_info(dev_desc, part_no, &info)) {
  97                 if (part_no != 0) {
  98                         printf("** Partition %d not valid on device %d **\n",
  99                                         part_no, dev_desc->devnum);
 100                         return -1;
 101                 }
 102
 103                 info.start = 0;
 104                 info.size = dev_desc->lba;
 105                 info.blksz = dev_desc->blksz;
 106                 info.name[0] = 0;
 107                 info.type[0] = 0;
 108                 info.bootable = 0;
 109 #if CONFIG_IS_ENABLED(PARTITION_UUIDS)
 110                 info.uuid[0] = 0;
 111 #endif
 112         }
 113
 114         return fat_set_blk_dev(dev_desc, &info);
 115 }
 116
 117 /*
 118  * Extract zero terminated short name from a directory entry.
 119  */
 120 static void get_name(dir_entry *dirent, char *s_name)
 121 {
 122         char *ptr;
 123
 124         memcpy(s_name, dirent->name, 8);
 125         s_name[8] = '\0';
 126         ptr = s_name;
 127         while (*ptr && *ptr != ' ')
 128                 ptr++;
 129         if (dirent->lcase & CASE_LOWER_BASE)
 130                 downcase(s_name, (unsigned)(ptr - s_name));
 131         if (dirent->ext[0] && dirent->ext[0] != ' ') {
 132                 *ptr++ = '.';
 133                 memcpy(ptr, dirent->ext, 3);
 134                 if (dirent->lcase & CASE_LOWER_EXT)
 135                         downcase(ptr, 3);
 136                 ptr[3] = '\0';
 137                 while (*ptr && *ptr != ' ')
 138                         ptr++;
 139         }
 140         *ptr = '\0';
 141         if (*s_name == DELETED_FLAG)
 142                 *s_name = '\0';
 143         else if (*s_name == aRING)
 144                 *s_name = DELETED_FLAG;
 145 }
 146
 147 static int flush_dirty_fat_buffer(fsdata *mydata);
 148 #if !defined(CONFIG_FAT_WRITE)
 149 /* Stub for read only operation */
 150 int flush_dirty_fat_buffer(fsdata *mydata)
 151 {
 152         (void)(mydata);
 153         return 0;
 154 }
 155 #endif
 156
 157 /*
 158  * Get the entry at index 'entry' in a FAT (12/16/32) table.
 159  * On failure 0x00 is returned.
 160  */
 161 static __u32 get_fatent(fsdata *mydata, __u32 entry)
 162 {
 163         __u32 bufnum;
 164         __u32 offset, off8;
 165         __u32 ret = 0x00;
 166
 167         if (CHECK_CLUST(entry, mydata->fatsize)) {
 168                 printf("Error: Invalid FAT entry: 0x%08x\n", entry);
 169                 return ret;
 170         }
 171
 172         switch (mydata->fatsize) {
 173         case 32:
 174                 bufnum = entry / FAT32BUFSIZE;
 175                 offset = entry - bufnum * FAT32BUFSIZE;
 176                 break;
 177         case 16:
 178                 bufnum = entry / FAT16BUFSIZE;
 179                 offset = entry - bufnum * FAT16BUFSIZE;
 180                 break;
 181         case 12:
 182                 bufnum = entry / FAT12BUFSIZE;
 183                 offset = entry - bufnum * FAT12BUFSIZE;
 184                 break;
 185
 186         default:
 187                 /* Unsupported FAT size */
 188                 return ret;
 189         }
 190
 191         debug("FAT%d: entry: 0x%08x = %d, offset: 0x%04x = %d\n",
 192                mydata->fatsize, entry, entry, offset, offset);
 193
 194         /* Read a new block of FAT entries into the cache. */
 195         if (bufnum != mydata->fatbufnum) {
 196                 __u32 getsize = FATBUFBLOCKS;
 197                 __u8 *bufptr = mydata->fatbuf;
 198                 __u32 fatlength = mydata->fatlength;
 199                 __u32 startblock = bufnum * FATBUFBLOCKS;
 200
 201                 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 202                 if (startblock + getsize > fatlength)
 203                         getsize = fatlength - startblock;
 204
 205                 startblock += mydata->fat_sect; /* Offset from start of disk */
 206
 207                 /* Write back the fatbuf to the disk */
 208                 if (flush_dirty_fat_buffer(mydata) < 0)
 209                         return -1;
 210
 211                 if (disk_read(startblock, getsize, bufptr) < 0) {
 212                         debug("Error reading FAT blocks\n");
 213                         return ret;
 214                 }
 215                 mydata->fatbufnum = bufnum;
 216         }
 217
 218         /* Get the actual entry from the table */
 219         switch (mydata->fatsize) {
 220         case 32:
 221                 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
 222                 break;
 223         case 16:
 224                 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
 225                 break;
 226         case 12:
 227                 off8 = (offset * 3) / 2;
 228                 /* fatbut + off8 may be unaligned, read in byte granularity */
 229                 ret = mydata->fatbuf[off8] + (mydata->fatbuf[off8 + 1] << 8);
 230
 231                 if (offset & 0x1)
 232                         ret >>= 4;
 233                 ret &= 0xfff;
 234         }
 235         debug("FAT%d: ret: 0x%08x, entry: 0x%08x, offset: 0x%04x\n",
 236                mydata->fatsize, ret, entry, offset);
 237
 238         return ret;
 239 }
 240
 241 /*
 242  * Read at most 'size' bytes from the specified cluster into 'buffer'.
 243  * Return 0 on success, -1 otherwise.
 244  */
 245 static int
 246 get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
 247 {
 248         __u32 idx = 0;
 249         __u32 startsect;
 250         int ret;
 251
 252         if (clustnum > 0) {
 253                 startsect = clust_to_sect(mydata, clustnum);
 254         } else {
 255                 startsect = mydata->rootdir_sect;
 256         }
 257
 258         debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
 259
 260         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 261                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 262
 263                 printf("FAT: Misaligned buffer address (%p)\n", buffer);
 264
 265                 while (size >= mydata->sect_size) {
 266                         ret = disk_read(startsect++, 1, tmpbuf);
 267                         if (ret != 1) {
 268                                 debug("Error reading data (got %d)\n", ret);
 269                                 return -1;
 270                         }
 271
 272                         memcpy(buffer, tmpbuf, mydata->sect_size);
 273                         buffer += mydata->sect_size;
 274                         size -= mydata->sect_size;
 275                 }
 276         } else {
 277                 idx = size / mydata->sect_size;
 278                 ret = disk_read(startsect, idx, buffer);
 279                 if (ret != idx) {
 280                         debug("Error reading data (got %d)\n", ret);
 281                         return -1;
 282                 }
 283                 startsect += idx;
 284                 idx *= mydata->sect_size;
 285                 buffer += idx;
 286                 size -= idx;
 287         }
 288         if (size) {
 289                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 290
 291                 ret = disk_read(startsect, 1, tmpbuf);
 292                 if (ret != 1) {
 293                         debug("Error reading data (got %d)\n", ret);
 294                         return -1;
 295                 }
 296
 297                 memcpy(buffer, tmpbuf, size);
 298         }
 299
 300         return 0;
 301 }
 302
 303 /*
 304  * Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
 305  * into 'buffer'.
 306  * Update the number of bytes read in *gotsize or return -1 on fatal errors.
 307  */
 308 __u8 get_contents_vfatname_block[MAX_CLUSTSIZE]
 309         __aligned(ARCH_DMA_MINALIGN);
 310
 311 static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
 312                         __u8 *buffer, loff_t maxsize, loff_t *gotsize)
 313 {
 314         loff_t filesize = FAT2CPU32(dentptr->size);
 315         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 316         __u32 curclust = START(dentptr);
 317         __u32 endclust, newclust;
 318         loff_t actsize;
 319
 320         *gotsize = 0;
 321         debug("Filesize: %llu bytes\n", filesize);
 322
 323         if (pos >= filesize) {
 324                 debug("Read position past EOF: %llu\n", pos);
 325                 return 0;
 326         }
 327
 328         if (maxsize > 0 && filesize > pos + maxsize)
 329                 filesize = pos + maxsize;
 330
 331         debug("%llu bytes\n", filesize);
 332
 333         actsize = bytesperclust;
 334
 335         /* go to cluster at pos */
 336         while (actsize <= pos) {
 337                 curclust = get_fatent(mydata, curclust);
 338                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 339                         debug("curclust: 0x%x\n", curclust);
 340                         debug("Invalid FAT entry\n");
 341                         return 0;
 342                 }
 343                 actsize += bytesperclust;
 344         }
 345
 346         /* actsize > pos */
 347         actsize -= bytesperclust;
 348         filesize -= actsize;
 349         pos -= actsize;
 350
 351         /* align to beginning of next cluster if any */
 352         if (pos) {
 353                 actsize = min(filesize, (loff_t)bytesperclust);
 354                 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
 355                                 (int)actsize) != 0) {
 356                         printf("Error reading cluster\n");
 357                         return -1;
 358                 }
 359                 filesize -= actsize;
 360                 actsize -= pos;
 361                 memcpy(buffer, get_contents_vfatname_block + pos, actsize);
 362                 *gotsize += actsize;
 363                 if (!filesize)
 364                         return 0;
 365                 buffer += actsize;
 366
 367                 curclust = get_fatent(mydata, curclust);
 368                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 369                         debug("curclust: 0x%x\n", curclust);
 370                         debug("Invalid FAT entry\n");
 371                         return 0;
 372                 }
 373         }
 374
 375         actsize = bytesperclust;
 376         endclust = curclust;
 377
 378         do {
 379                 /* search for consecutive clusters */
 380                 while (actsize < filesize) {
 381                         newclust = get_fatent(mydata, endclust);
 382                         if ((newclust - 1) != endclust)
 383                                 goto getit;
 384                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 385                                 debug("curclust: 0x%x\n", newclust);
 386                                 debug("Invalid FAT entry\n");
 387                                 return 0;
 388                         }
 389                         endclust = newclust;
 390                         actsize += bytesperclust;
 391                 }
 392
 393                 /* get remaining bytes */
 394                 actsize = filesize;
 395                 if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 396                         printf("Error reading cluster\n");
 397                         return -1;
 398                 }
 399                 *gotsize += actsize;
 400                 return 0;
 401 getit:
 402                 if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 403                         printf("Error reading cluster\n");
 404                         return -1;
 405                 }
 406                 *gotsize += (int)actsize;
 407                 filesize -= actsize;
 408                 buffer += actsize;
 409
 410                 curclust = get_fatent(mydata, endclust);
 411                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 412                         debug("curclust: 0x%x\n", curclust);
 413                         printf("Invalid FAT entry\n");
 414                         return 0;
 415                 }
 416                 actsize = bytesperclust;
 417                 endclust = curclust;
 418         } while (1);
 419 }
 420
 421 /*
 422  * Extract the file name information from 'slotptr' into 'l_name',
 423  * starting at l_name[*idx].
 424  * Return 1 if terminator (zero byte) is found, 0 otherwise.
 425  */
 426 static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
 427 {
 428         int j;
 429
 430         for (j = 0; j <= 8; j += 2) {
 431                 l_name[*idx] = slotptr->name0_4[j];
 432                 if (l_name[*idx] == 0x00)
 433                         return 1;
 434                 (*idx)++;
 435         }
 436         for (j = 0; j <= 10; j += 2) {
 437                 l_name[*idx] = slotptr->name5_10[j];
 438                 if (l_name[*idx] == 0x00)
 439                         return 1;
 440                 (*idx)++;
 441         }
 442         for (j = 0; j <= 2; j += 2) {
 443                 l_name[*idx] = slotptr->name11_12[j];
 444                 if (l_name[*idx] == 0x00)
 445                         return 1;
 446                 (*idx)++;
 447         }
 448
 449         return 0;
 450 }
 451
 452 /* Calculate short name checksum */
 453 static __u8 mkcksum(const char name[8], const char ext[3])
 454 {
 455         int i;
 456
 457         __u8 ret = 0;
 458
 459         for (i = 0; i < 8; i++)
 460                 ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
 461         for (i = 0; i < 3; i++)
 462                 ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
 463
 464         return ret;
 465 }
 466
 467 /*
 468  * TODO these should go away once fat_write is reworked to use the
 469  * directory iterator
 470  */
 471 __u8 get_dentfromdir_block[MAX_CLUSTSIZE]
 472         __aligned(ARCH_DMA_MINALIGN);
 473 __u8 do_fat_read_at_block[MAX_CLUSTSIZE]
 474         __aligned(ARCH_DMA_MINALIGN);
 475
 476 /*
 477  * Read boot sector and volume info from a FAT filesystem
 478  */
 479 static int
 480 read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
 481 {
 482         __u8 *block;
 483         volume_info *vistart;
 484         int ret = 0;
 485
 486         if (cur_dev == NULL) {
 487                 debug("Error: no device selected\n");
 488                 return -1;
 489         }
 490
 491         block = malloc_cache_aligned(cur_dev->blksz);
 492         if (block == NULL) {
 493                 debug("Error: allocating block\n");
 494                 return -1;
 495         }
 496
 497         if (disk_read(0, 1, block) < 0) {
 498                 debug("Error: reading block\n");
 499                 goto fail;
 500         }
 501
 502         memcpy(bs, block, sizeof(boot_sector));
 503         bs->reserved = FAT2CPU16(bs->reserved);
 504         bs->fat_length = FAT2CPU16(bs->fat_length);
 505         bs->secs_track = FAT2CPU16(bs->secs_track);
 506         bs->heads = FAT2CPU16(bs->heads);
 507         bs->total_sect = FAT2CPU32(bs->total_sect);
 508
 509         /* FAT32 entries */
 510         if (bs->fat_length == 0) {
 511                 /* Assume FAT32 */
 512                 bs->fat32_length = FAT2CPU32(bs->fat32_length);
 513                 bs->flags = FAT2CPU16(bs->flags);
 514                 bs->root_cluster = FAT2CPU32(bs->root_cluster);
 515                 bs->info_sector = FAT2CPU16(bs->info_sector);
 516                 bs->backup_boot = FAT2CPU16(bs->backup_boot);
 517                 vistart = (volume_info *)(block + sizeof(boot_sector));
 518                 *fatsize = 32;
 519         } else {
 520                 vistart = (volume_info *)&(bs->fat32_length);
 521                 *fatsize = 0;
 522         }
 523         memcpy(volinfo, vistart, sizeof(volume_info));
 524
 525         if (*fatsize == 32) {
 526                 if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
 527                         goto exit;
 528         } else {
 529                 if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
 530                         *fatsize = 12;
 531                         goto exit;
 532                 }
 533                 if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
 534                         *fatsize = 16;
 535                         goto exit;
 536                 }
 537         }
 538
 539         debug("Error: broken fs_type sign\n");
 540 fail:
 541         ret = -1;
 542 exit:
 543         free(block);
 544         return ret;
 545 }
 546
 547 static int get_fs_info(fsdata *mydata)
 548 {
 549         boot_sector bs;
 550         volume_info volinfo;
 551         int ret;
 552
 553         ret = read_bootsectandvi(&bs, &volinfo, &mydata->fatsize);
 554         if (ret) {
 555                 debug("Error: reading boot sector\n");
 556                 return ret;
 557         }
 558
 559         if (mydata->fatsize == 32) {
 560                 mydata->fatlength = bs.fat32_length;
 561         } else {
 562                 mydata->fatlength = bs.fat_length;
 563         }
 564
 565         mydata->fat_sect = bs.reserved;
 566
 567         mydata->rootdir_sect = mydata->fat_sect + mydata->fatlength * bs.fats;
 568
 569         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
 570         mydata->clust_size = bs.cluster_size;
 571         if (mydata->sect_size != cur_part_info.blksz) {
 572                 printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
 573                                 mydata->sect_size, cur_part_info.blksz);
 574                 return -1;
 575         }
 576
 577         if (mydata->fatsize == 32) {
 578                 mydata->data_begin = mydata->rootdir_sect -
 579                                         (mydata->clust_size * 2);
 580                 mydata->root_cluster = bs.root_cluster;
 581         } else {
 582                 mydata->rootdir_size = ((bs.dir_entries[1]  * (int)256 +
 583                                          bs.dir_entries[0]) *
 584                                          sizeof(dir_entry)) /
 585                                          mydata->sect_size;
 586                 mydata->data_begin = mydata->rootdir_sect +
 587                                         mydata->rootdir_size -
 588                                         (mydata->clust_size * 2);
 589                 mydata->root_cluster =
 590                         sect_to_clust(mydata, mydata->rootdir_sect);
 591         }
 592
 593         mydata->fatbufnum = -1;
 594         mydata->fat_dirty = 0;
 595         mydata->fatbuf = malloc_cache_aligned(FATBUFSIZE);
 596         if (mydata->fatbuf == NULL) {
 597                 debug("Error: allocating memory\n");
 598                 return -1;
 599         }
 600
 601         debug("FAT%d, fat_sect: %d, fatlength: %d\n",
 602                mydata->fatsize, mydata->fat_sect, mydata->fatlength);
 603         debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
 604                "Data begins at: %d\n",
 605                mydata->root_cluster,
 606                mydata->rootdir_sect,
 607                mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
 608         debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
 609               mydata->clust_size);
 610
 611         return 0;
 612 }
 613
 614
 615 /*
 616  * Directory iterator, to simplify filesystem traversal
 617  *
 618  * Implements an iterator pattern to traverse directory tables,
 619  * transparently handling directory tables split across multiple
 620  * clusters, and the difference between FAT12/FAT16 root directory
 621  * (contiguous) and subdirectories + FAT32 root (chained).
 622  *
 623  * Rough usage:
 624  *
 625  *   for (fat_itr_root(&itr, fsdata); fat_itr_next(&itr); ) {
 626  *      // to traverse down to a subdirectory pointed to by
 627  *      // current iterator position:
 628  *      fat_itr_child(&itr, &itr);
 629  *   }
 630  *
 631  * For more complete example, see fat_itr_resolve()
 632  */
 633
 634 typedef struct {
 635         fsdata    *fsdata;        /* filesystem parameters */
 636         unsigned   clust;         /* current cluster */
 637         int        last_cluster;  /* set once we've read last cluster */
 638         int        is_root;       /* is iterator at root directory */
 639         int        remaining;     /* remaining dent's in current cluster */
 640
 641         /* current iterator position values: */
 642         dir_entry *dent;          /* current directory entry */
 643         char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
 644         char       s_name[14];    /* short 8.3 name */
 645         char      *name;          /* l_name if there is one, else s_name */
 646
 647         /* storage for current cluster in memory: */
 648         u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
 649 } fat_itr;
 650
 651 static int fat_itr_isdir(fat_itr *itr);
 652
 653 /**
 654  * fat_itr_root() - initialize an iterator to start at the root
 655  * directory
 656  *
 657  * @itr: iterator to initialize
 658  * @fsdata: filesystem data for the partition
 659  * @return 0 on success, else -errno
 660  */
 661 static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
 662 {
 663         if (get_fs_info(fsdata))
 664                 return -ENXIO;
 665
 666         itr->fsdata = fsdata;
 667         itr->clust = fsdata->root_cluster;
 668         itr->dent = NULL;
 669         itr->remaining = 0;
 670         itr->last_cluster = 0;
 671         itr->is_root = 1;
 672
 673         return 0;
 674 }
 675
 676 /**
 677  * fat_itr_child() - initialize an iterator to descend into a sub-
 678  * directory
 679  *
 680  * Initializes 'itr' to iterate the contents of the directory at
 681  * the current cursor position of 'parent'.  It is an error to
 682  * call this if the current cursor of 'parent' is pointing at a
 683  * regular file.
 684  *
 685  * Note that 'itr' and 'parent' can be the same pointer if you do
 686  * not need to preserve 'parent' after this call, which is useful
 687  * for traversing directory structure to resolve a file/directory.
 688  *
 689  * @itr: iterator to initialize
 690  * @parent: the iterator pointing at a directory entry in the
 691  *    parent directory of the directory to iterate
 692  */
 693 static void fat_itr_child(fat_itr *itr, fat_itr *parent)
 694 {
 695         fsdata *mydata = parent->fsdata;  /* for silly macros */
 696         unsigned clustnum = START(parent->dent);
 697
 698         assert(fat_itr_isdir(parent));
 699
 700         itr->fsdata = parent->fsdata;
 701         if (clustnum > 0) {
 702                 itr->clust = clustnum;
 703                 itr->is_root = 0;
 704         } else {
 705                 itr->clust = parent->fsdata->root_cluster;
 706                 itr->is_root = 1;
 707         }
 708         itr->dent = NULL;
 709         itr->remaining = 0;
 710         itr->last_cluster = 0;
 711 }
 712
 713 static void *next_cluster(fat_itr *itr)
 714 {
 715         fsdata *mydata = itr->fsdata;  /* for silly macros */
 716         int ret;
 717         u32 sect;
 718
 719         /* have we reached the end? */
 720         if (itr->last_cluster)
 721                 return NULL;
 722
 723         sect = clust_to_sect(itr->fsdata, itr->clust);
 724
 725         debug("FAT read(sect=%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
 726               sect, itr->fsdata->clust_size, DIRENTSPERBLOCK);
 727
 728         /*
 729          * NOTE: do_fat_read_at() had complicated logic to deal w/
 730          * vfat names that span multiple clusters in the fat16 case,
 731          * which get_dentfromdir() probably also needed (and was
 732          * missing).  And not entirely sure what fat32 didn't have
 733          * the same issue..  We solve that by only caring about one
 734          * dent at a time and iteratively constructing the vfat long
 735          * name.
 736          */
 737         ret = disk_read(sect, itr->fsdata->clust_size,
 738                         itr->block);
 739         if (ret < 0) {
 740                 debug("Error: reading block\n");
 741                 return NULL;
 742         }
 743
 744         if (itr->is_root && itr->fsdata->fatsize != 32) {
 745                 itr->clust++;
 746                 sect = clust_to_sect(itr->fsdata, itr->clust);
 747                 if (sect - itr->fsdata->rootdir_sect >=
 748                     itr->fsdata->rootdir_size) {
 749                         debug("cursect: 0x%x\n", itr->clust);
 750                         itr->last_cluster = 1;
 751                 }
 752         } else {
 753                 itr->clust = get_fatent(itr->fsdata, itr->clust);
 754                 if (CHECK_CLUST(itr->clust, itr->fsdata->fatsize)) {
 755                         debug("cursect: 0x%x\n", itr->clust);
 756                         itr->last_cluster = 1;
 757                 }
 758         }
 759
 760         return itr->block;
 761 }
 762
 763 static dir_entry *next_dent(fat_itr *itr)
 764 {
 765         if (itr->remaining == 0) {
 766                 struct dir_entry *dent = next_cluster(itr);
 767                 unsigned nbytes = itr->fsdata->sect_size *
 768                         itr->fsdata->clust_size;
 769
 770                 /* have we reached the last cluster? */
 771                 if (!dent)
 772                         return NULL;
 773
 774                 itr->remaining = nbytes / sizeof(dir_entry) - 1;
 775                 itr->dent = dent;
 776         } else {
 777                 itr->remaining--;
 778                 itr->dent++;
 779         }
 780
 781         /* have we reached the last valid entry? */
 782         if (itr->dent->name[0] == 0)
 783                 return NULL;
 784
 785         return itr->dent;
 786 }
 787
 788 static dir_entry *extract_vfat_name(fat_itr *itr)
 789 {
 790         struct dir_entry *dent = itr->dent;
 791         int seqn = itr->dent->name[0] & ~LAST_LONG_ENTRY_MASK;
 792         u8 chksum, alias_checksum = ((dir_slot *)dent)->alias_checksum;
 793         int n = 0;
 794
 795         while (seqn--) {
 796                 char buf[13];
 797                 int idx = 0;
 798
 799                 slot2str((dir_slot *)dent, buf, &idx);
 800
 801                 /* shift accumulated long-name up and copy new part in: */
 802                 memmove(itr->l_name + idx, itr->l_name, n);
 803                 memcpy(itr->l_name, buf, idx);
 804                 n += idx;
 805
 806                 dent = next_dent(itr);
 807                 if (!dent)
 808                         return NULL;
 809         }
 810
 811         itr->l_name[n] = '\0';
 812
 813         chksum = mkcksum(dent->name, dent->ext);
 814
 815         /* checksum mismatch could mean deleted file, etc.. skip it: */
 816         if (chksum != alias_checksum) {
 817                 debug("** chksum=%x, alias_checksum=%x, l_name=%s, s_name=%8s.%3s\n",
 818                       chksum, alias_checksum, itr->l_name, dent->name, dent->ext);
 819                 return NULL;
 820         }
 821
 822         return dent;
 823 }
 824
 825 /**
 826  * fat_itr_next() - step to the next entry in a directory
 827  *
 828  * Must be called once on a new iterator before the cursor is valid.
 829  *
 830  * @itr: the iterator to iterate
 831  * @return boolean, 1 if success or 0 if no more entries in the
 832  *    current directory
 833  */
 834 static int fat_itr_next(fat_itr *itr)
 835 {
 836         dir_entry *dent;
 837
 838         itr->name = NULL;
 839
 840         while (1) {
 841                 dent = next_dent(itr);
 842                 if (!dent)
 843                         return 0;
 844
 845                 if (dent->name[0] == DELETED_FLAG ||
 846                     dent->name[0] == aRING)
 847                         continue;
 848
 849                 if (dent->attr & ATTR_VOLUME) {
 850                         if ((dent->attr & ATTR_VFAT) == ATTR_VFAT &&
 851                             (dent->name[0] & LAST_LONG_ENTRY_MASK)) {
 852                                 dent = extract_vfat_name(itr);
 853                                 if (!dent)
 854                                         continue;
 855                                 itr->name = itr->l_name;
 856                                 break;
 857                         } else {
 858                                 /* Volume label or VFAT entry, skip */
 859                                 continue;
 860                         }
 861                 }
 862
 863                 break;
 864         }
 865
 866         get_name(dent, itr->s_name);
 867         if (!itr->name)
 868                 itr->name = itr->s_name;
 869
 870         return 1;
 871 }
 872
 873 /**
 874  * fat_itr_isdir() - is current cursor position pointing to a directory
 875  *
 876  * @itr: the iterator
 877  * @return true if cursor is at a directory
 878  */
 879 static int fat_itr_isdir(fat_itr *itr)
 880 {
 881         return !!(itr->dent->attr & ATTR_DIR);
 882 }
 883
 884 /*
 885  * Helpers:
 886  */
 887
 888 #define TYPE_FILE 0x1
 889 #define TYPE_DIR  0x2
 890 #define TYPE_ANY  (TYPE_FILE | TYPE_DIR)
 891
 892 /**
 893  * fat_itr_resolve() - traverse directory structure to resolve the
 894  * requested path.
 895  *
 896  * Traverse directory structure to the requested path.  If the specified
 897  * path is to a directory, this will descend into the directory and
 898  * leave it iterator at the start of the directory.  If the path is to a
 899  * file, it will leave the iterator in the parent directory with current
 900  * cursor at file's entry in the directory.
 901  *
 902  * @itr: iterator initialized to root
 903  * @path: the requested path
 904  * @type: bitmask of allowable file types
 905  * @return 0 on success or -errno
 906  */
 907 static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
 908 {
 909         const char *next;
 910
 911         /* chomp any extra leading slashes: */
 912         while (path[0] && ISDIRDELIM(path[0]))
 913                 path++;
 914
 915         /* are we at the end? */
 916         if (strlen(path) == 0) {
 917                 if (!(type & TYPE_DIR))
 918                         return -ENOENT;
 919                 return 0;
 920         }
 921
 922         /* find length of next path entry: */
 923         next = path;
 924         while (next[0] && !ISDIRDELIM(next[0]))
 925                 next++;
 926
 927         while (fat_itr_next(itr)) {
 928                 int match = 0;
 929                 unsigned n = max(strlen(itr->name), (size_t)(next - path));
 930
 931                 /* check both long and short name: */
 932                 if (!strncasecmp(path, itr->name, n))
 933                         match = 1;
 934                 else if (itr->name != itr->s_name &&
 935                          !strncasecmp(path, itr->s_name, n))
 936                         match = 1;
 937
 938                 if (!match)
 939                         continue;
 940
 941                 if (fat_itr_isdir(itr)) {
 942                         /* recurse into directory: */
 943                         fat_itr_child(itr, itr);
 944                         return fat_itr_resolve(itr, next, type);
 945                 } else if (next[0]) {
 946                         /*
 947                          * If next is not empty then we have a case
 948                          * like: /path/to/realfile/nonsense
 949                          */
 950                         debug("bad trailing path: %s\n", next);
 951                         return -ENOENT;
 952                 } else if (!(type & TYPE_FILE)) {
 953                         return -ENOTDIR;
 954                 } else {
 955                         return 0;
 956                 }
 957         }
 958
 959         return -ENOENT;
 960 }
 961
 962 int file_fat_detectfs(void)
 963 {
 964         boot_sector bs;
 965         volume_info volinfo;
 966         int fatsize;
 967         char vol_label[12];
 968
 969         if (cur_dev == NULL) {
 970                 printf("No current device\n");
 971                 return 1;
 972         }
 973
 974 #if defined(CONFIG_IDE) || \
 975     defined(CONFIG_SATA) || \
 976     defined(CONFIG_SCSI) || \
 977     defined(CONFIG_CMD_USB) || \
 978     defined(CONFIG_MMC)
 979         printf("Interface:  ");
 980         switch (cur_dev->if_type) {
 981         case IF_TYPE_IDE:
 982                 printf("IDE");
 983                 break;
 984         case IF_TYPE_SATA:
 985                 printf("SATA");
 986                 break;
 987         case IF_TYPE_SCSI:
 988                 printf("SCSI");
 989                 break;
 990         case IF_TYPE_ATAPI:
 991                 printf("ATAPI");
 992                 break;
 993         case IF_TYPE_USB:
 994                 printf("USB");
 995                 break;
 996         case IF_TYPE_DOC:
 997                 printf("DOC");
 998                 break;
 999         case IF_TYPE_MMC:
1000                 printf("MMC");
1001                 break;
1002         default:
1003                 printf("Unknown");
1004         }
1005
1006         printf("\n  Device %d: ", cur_dev->devnum);
1007         dev_print(cur_dev);
1008 #endif
1009
1010         if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1011                 printf("\nNo valid FAT fs found\n");
1012                 return 1;
1013         }
1014
1015         memcpy(vol_label, volinfo.volume_label, 11);
1016         vol_label[11] = '\0';
1017         volinfo.fs_type[5] = '\0';
1018
1019         printf("Filesystem: %s \"%s\"\n", volinfo.fs_type, vol_label);
1020
1021         return 0;
1022 }
1023
1024 int fat_exists(const char *filename)
1025 {
1026         fsdata fsdata;
1027         fat_itr *itr;
1028         int ret;
1029
1030         itr = malloc_cache_aligned(sizeof(fat_itr));
1031         if (!itr)
1032                 return 0;
1033         ret = fat_itr_root(itr, &fsdata);
1034         if (ret)
1035                 goto out;
1036
1037         ret = fat_itr_resolve(itr, filename, TYPE_ANY);
1038         free(fsdata.fatbuf);
1039 out:
1040         free(itr);
1041         return ret == 0;
1042 }
1043
1044 int fat_size(const char *filename, loff_t *size)
1045 {
1046         fsdata fsdata;
1047         fat_itr *itr;
1048         int ret;
1049
1050         itr = malloc_cache_aligned(sizeof(fat_itr));
1051         if (!itr)
1052                 return -ENOMEM;
1053         ret = fat_itr_root(itr, &fsdata);
1054         if (ret)
1055                 goto out_free_itr;
1056
1057         ret = fat_itr_resolve(itr, filename, TYPE_FILE);
1058         if (ret) {
1059                 /*
1060                  * Directories don't have size, but fs_size() is not
1061                  * expected to fail if passed a directory path:
1062                  */
1063                 free(fsdata.fatbuf);
1064                 fat_itr_root(itr, &fsdata);
1065                 if (!fat_itr_resolve(itr, filename, TYPE_DIR)) {
1066                         *size = 0;
1067                         ret = 0;
1068                 }
1069                 goto out_free_both;
1070         }
1071
1072         *size = FAT2CPU32(itr->dent->size);
1073 out_free_both:
1074         free(fsdata.fatbuf);
1075 out_free_itr:
1076         free(itr);
1077         return ret;
1078 }
1079
1080 int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
1081                      loff_t maxsize, loff_t *actread)
1082 {
1083         fsdata fsdata;
1084         fat_itr *itr;
1085         int ret;
1086
1087         itr = malloc_cache_aligned(sizeof(fat_itr));
1088         if (!itr)
1089                 return -ENOMEM;
1090         ret = fat_itr_root(itr, &fsdata);
1091         if (ret)
1092                 goto out_free_itr;
1093
1094         ret = fat_itr_resolve(itr, filename, TYPE_FILE);
1095         if (ret)
1096                 goto out_free_both;
1097
1098         debug("reading %s\n", filename);
1099         ret = get_contents(&fsdata, itr->dent, pos, buffer, maxsize, actread);
1100
1101 out_free_both:
1102         free(fsdata.fatbuf);
1103 out_free_itr:
1104         free(itr);
1105         return ret;
1106 }
1107
1108 int file_fat_read(const char *filename, void *buffer, int maxsize)
1109 {
1110         loff_t actread;
1111         int ret;
1112
1113         ret =  file_fat_read_at(filename, 0, buffer, maxsize, &actread);
1114         if (ret)
1115                 return ret;
1116         else
1117                 return actread;
1118 }
1119
1120 int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
1121                   loff_t *actread)
1122 {
1123         int ret;
1124
1125         ret = file_fat_read_at(filename, offset, buf, len, actread);
1126         if (ret)
1127                 printf("** Unable to read file %s **\n", filename);
1128
1129         return ret;
1130 }
1131
1132 typedef struct {
1133         struct fs_dir_stream parent;
1134         struct fs_dirent dirent;
1135         fsdata fsdata;
1136         fat_itr itr;
1137 } fat_dir;
1138
1139 int fat_opendir(const char *filename, struct fs_dir_stream **dirsp)
1140 {
1141         fat_dir *dir;
1142         int ret;
1143
1144         dir = malloc_cache_aligned(sizeof(*dir));
1145         if (!dir)
1146                 return -ENOMEM;
1147         memset(dir, 0, sizeof(*dir));
1148
1149         ret = fat_itr_root(&dir->itr, &dir->fsdata);
1150         if (ret)
1151                 goto fail_free_dir;
1152
1153         ret = fat_itr_resolve(&dir->itr, filename, TYPE_DIR);
1154         if (ret)
1155                 goto fail_free_both;
1156
1157         *dirsp = (struct fs_dir_stream *)dir;
1158         return 0;
1159
1160 fail_free_both:
1161         free(dir->fsdata.fatbuf);
1162 fail_free_dir:
1163         free(dir);
1164         return ret;
1165 }
1166
1167 int fat_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp)
1168 {
1169         fat_dir *dir = (fat_dir *)dirs;
1170         struct fs_dirent *dent = &dir->dirent;
1171
1172         if (!fat_itr_next(&dir->itr))
1173                 return -ENOENT;
1174
1175         memset(dent, 0, sizeof(*dent));
1176         strcpy(dent->name, dir->itr.name);
1177
1178         if (fat_itr_isdir(&dir->itr)) {
1179                 dent->type = FS_DT_DIR;
1180         } else {
1181                 dent->type = FS_DT_REG;
1182                 dent->size = FAT2CPU32(dir->itr.dent->size);
1183         }
1184
1185         *dentp = dent;
1186
1187         return 0;
1188 }
1189
1190 void fat_closedir(struct fs_dir_stream *dirs)
1191 {
1192         fat_dir *dir = (fat_dir *)dirs;
1193         free(dir->fsdata.fatbuf);
1194         free(dir);
1195 }
1196
1197 void fat_close(void)
1198 {
1199 }