fs/fat/fat.c

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