git.sur5r.net Git - u-boot/blob - fs/fat/fat_write.c

   1 /*
   2  * fat_write.c
   3  *
   4  * R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <command.h>
  11 #include <config.h>
  12 #include <fat.h>
  13 #include <asm/byteorder.h>
  14 #include <part.h>
  15 #include <linux/ctype.h>
  16 #include <div64.h>
  17 #include <linux/math64.h>
  18 #include "fat.c"
  19
  20 static void uppercase(char *str, int len)
  21 {
  22         int i;
  23
  24         for (i = 0; i < len; i++) {
  25                 *str = toupper(*str);
  26                 str++;
  27         }
  28 }
  29
  30 static int total_sector;
  31 static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
  32 {
  33         ulong ret;
  34
  35         if (!cur_dev)
  36                 return -1;
  37
  38         if (cur_part_info.start + block + nr_blocks >
  39                 cur_part_info.start + total_sector) {
  40                 printf("error: overflow occurs\n");
  41                 return -1;
  42         }
  43
  44         ret = blk_dwrite(cur_dev, cur_part_info.start + block, nr_blocks, buf);
  45         if (nr_blocks && ret == 0)
  46                 return -1;
  47
  48         return ret;
  49 }
  50
  51 /*
  52  * Set short name in directory entry
  53  */
  54 static void set_name(dir_entry *dirent, const char *filename)
  55 {
  56         char s_name[VFAT_MAXLEN_BYTES];
  57         char *period;
  58         int period_location, len, i, ext_num;
  59
  60         if (filename == NULL)
  61                 return;
  62
  63         len = strlen(filename);
  64         if (len == 0)
  65                 return;
  66
  67         strcpy(s_name, filename);
  68         uppercase(s_name, len);
  69
  70         period = strchr(s_name, '.');
  71         if (period == NULL) {
  72                 period_location = len;
  73                 ext_num = 0;
  74         } else {
  75                 period_location = period - s_name;
  76                 ext_num = len - period_location - 1;
  77         }
  78
  79         /* Pad spaces when the length of file name is shorter than eight */
  80         if (period_location < 8) {
  81                 memcpy(dirent->name, s_name, period_location);
  82                 for (i = period_location; i < 8; i++)
  83                         dirent->name[i] = ' ';
  84         } else if (period_location == 8) {
  85                 memcpy(dirent->name, s_name, period_location);
  86         } else {
  87                 memcpy(dirent->name, s_name, 6);
  88                 dirent->name[6] = '~';
  89                 dirent->name[7] = '1';
  90         }
  91
  92         if (ext_num < 3) {
  93                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
  94                 for (i = ext_num; i < 3; i++)
  95                         dirent->ext[i] = ' ';
  96         } else
  97                 memcpy(dirent->ext, s_name + period_location + 1, 3);
  98
  99         debug("name : %s\n", dirent->name);
 100         debug("ext : %s\n", dirent->ext);
 101 }
 102
 103 static __u8 num_of_fats;
 104 /*
 105  * Write fat buffer into block device
 106  */
 107 static int flush_fat_buffer(fsdata *mydata)
 108 {
 109         int getsize = FATBUFBLOCKS;
 110         __u32 fatlength = mydata->fatlength;
 111         __u8 *bufptr = mydata->fatbuf;
 112         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 113
 114         startblock += mydata->fat_sect;
 115
 116         if (getsize > fatlength)
 117                 getsize = fatlength;
 118
 119         /* Write FAT buf */
 120         if (disk_write(startblock, getsize, bufptr) < 0) {
 121                 debug("error: writing FAT blocks\n");
 122                 return -1;
 123         }
 124
 125         if (num_of_fats == 2) {
 126                 /* Update corresponding second FAT blocks */
 127                 startblock += mydata->fatlength;
 128                 if (disk_write(startblock, getsize, bufptr) < 0) {
 129                         debug("error: writing second FAT blocks\n");
 130                         return -1;
 131                 }
 132         }
 133
 134         return 0;
 135 }
 136
 137 /*
 138  * Get the entry at index 'entry' in a FAT (12/16/32) table.
 139  * On failure 0x00 is returned.
 140  * When bufnum is changed, write back the previous fatbuf to the disk.
 141  */
 142 static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
 143 {
 144         __u32 bufnum;
 145         __u32 off16, offset;
 146         __u32 ret = 0x00;
 147         __u16 val1, val2;
 148
 149         if (CHECK_CLUST(entry, mydata->fatsize)) {
 150                 printf("Error: Invalid FAT entry: 0x%08x\n", entry);
 151                 return ret;
 152         }
 153
 154         switch (mydata->fatsize) {
 155         case 32:
 156                 bufnum = entry / FAT32BUFSIZE;
 157                 offset = entry - bufnum * FAT32BUFSIZE;
 158                 break;
 159         case 16:
 160                 bufnum = entry / FAT16BUFSIZE;
 161                 offset = entry - bufnum * FAT16BUFSIZE;
 162                 break;
 163         case 12:
 164                 bufnum = entry / FAT12BUFSIZE;
 165                 offset = entry - bufnum * FAT12BUFSIZE;
 166                 break;
 167
 168         default:
 169                 /* Unsupported FAT size */
 170                 return ret;
 171         }
 172
 173         debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
 174                mydata->fatsize, entry, entry, offset, offset);
 175
 176         /* Read a new block of FAT entries into the cache. */
 177         if (bufnum != mydata->fatbufnum) {
 178                 int getsize = FATBUFBLOCKS;
 179                 __u8 *bufptr = mydata->fatbuf;
 180                 __u32 fatlength = mydata->fatlength;
 181                 __u32 startblock = bufnum * FATBUFBLOCKS;
 182
 183                 if (getsize > fatlength)
 184                         getsize = fatlength;
 185
 186                 fatlength *= mydata->sect_size; /* We want it in bytes now */
 187                 startblock += mydata->fat_sect; /* Offset from start of disk */
 188
 189                 /* Write back the fatbuf to the disk */
 190                 if (mydata->fatbufnum != -1) {
 191                         if (flush_fat_buffer(mydata) < 0)
 192                                 return -1;
 193                 }
 194
 195                 if (disk_read(startblock, getsize, bufptr) < 0) {
 196                         debug("Error reading FAT blocks\n");
 197                         return ret;
 198                 }
 199                 mydata->fatbufnum = bufnum;
 200         }
 201
 202         /* Get the actual entry from the table */
 203         switch (mydata->fatsize) {
 204         case 32:
 205                 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
 206                 break;
 207         case 16:
 208                 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
 209                 break;
 210         case 12:
 211                 off16 = (offset * 3) / 4;
 212
 213                 switch (offset & 0x3) {
 214                 case 0:
 215                         ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
 216                         ret &= 0xfff;
 217                         break;
 218                 case 1:
 219                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 220                         val1 &= 0xf000;
 221                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 222                         val2 &= 0x00ff;
 223                         ret = (val2 << 4) | (val1 >> 12);
 224                         break;
 225                 case 2:
 226                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 227                         val1 &= 0xff00;
 228                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 229                         val2 &= 0x000f;
 230                         ret = (val2 << 8) | (val1 >> 8);
 231                         break;
 232                 case 3:
 233                         ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 234                         ret = (ret & 0xfff0) >> 4;
 235                         break;
 236                 default:
 237                         break;
 238                 }
 239                 break;
 240         }
 241         debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
 242                mydata->fatsize, ret, entry, offset);
 243
 244         return ret;
 245 }
 246
 247 /*
 248  * Set the file name information from 'name' into 'slotptr',
 249  */
 250 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 251 {
 252         int j, end_idx = 0;
 253
 254         for (j = 0; j <= 8; j += 2) {
 255                 if (name[*idx] == 0x00) {
 256                         slotptr->name0_4[j] = 0;
 257                         slotptr->name0_4[j + 1] = 0;
 258                         end_idx++;
 259                         goto name0_4;
 260                 }
 261                 slotptr->name0_4[j] = name[*idx];
 262                 (*idx)++;
 263                 end_idx++;
 264         }
 265         for (j = 0; j <= 10; j += 2) {
 266                 if (name[*idx] == 0x00) {
 267                         slotptr->name5_10[j] = 0;
 268                         slotptr->name5_10[j + 1] = 0;
 269                         end_idx++;
 270                         goto name5_10;
 271                 }
 272                 slotptr->name5_10[j] = name[*idx];
 273                 (*idx)++;
 274                 end_idx++;
 275         }
 276         for (j = 0; j <= 2; j += 2) {
 277                 if (name[*idx] == 0x00) {
 278                         slotptr->name11_12[j] = 0;
 279                         slotptr->name11_12[j + 1] = 0;
 280                         end_idx++;
 281                         goto name11_12;
 282                 }
 283                 slotptr->name11_12[j] = name[*idx];
 284                 (*idx)++;
 285                 end_idx++;
 286         }
 287
 288         if (name[*idx] == 0x00)
 289                 return 1;
 290
 291         return 0;
 292 /* Not used characters are filled with 0xff 0xff */
 293 name0_4:
 294         for (; end_idx < 5; end_idx++) {
 295                 slotptr->name0_4[end_idx * 2] = 0xff;
 296                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 297         }
 298         end_idx = 5;
 299 name5_10:
 300         end_idx -= 5;
 301         for (; end_idx < 6; end_idx++) {
 302                 slotptr->name5_10[end_idx * 2] = 0xff;
 303                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 304         }
 305         end_idx = 11;
 306 name11_12:
 307         end_idx -= 11;
 308         for (; end_idx < 2; end_idx++) {
 309                 slotptr->name11_12[end_idx * 2] = 0xff;
 310                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 311         }
 312
 313         return 1;
 314 }
 315
 316 static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
 317 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
 318
 319 /*
 320  * Fill dir_slot entries with appropriate name, id, and attr
 321  * The real directory entry is returned by 'dentptr'
 322  */
 323 static void
 324 fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
 325 {
 326         dir_slot *slotptr = (dir_slot *)get_contents_vfatname_block;
 327         __u8 counter = 0, checksum;
 328         int idx = 0, ret;
 329         char s_name[16];
 330
 331         /* Get short file name and checksum value */
 332         strncpy(s_name, (*dentptr)->name, 16);
 333         checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
 334
 335         do {
 336                 memset(slotptr, 0x00, sizeof(dir_slot));
 337                 ret = str2slot(slotptr, l_name, &idx);
 338                 slotptr->id = ++counter;
 339                 slotptr->attr = ATTR_VFAT;
 340                 slotptr->alias_checksum = checksum;
 341                 slotptr++;
 342         } while (ret == 0);
 343
 344         slotptr--;
 345         slotptr->id |= LAST_LONG_ENTRY_MASK;
 346
 347         while (counter >= 1) {
 348                 if (is_next_clust(mydata, *dentptr)) {
 349                         /* A new cluster is allocated for directory table */
 350                         flush_dir_table(mydata, dentptr);
 351                 }
 352                 memcpy(*dentptr, slotptr, sizeof(dir_slot));
 353                 (*dentptr)++;
 354                 slotptr--;
 355                 counter--;
 356         }
 357
 358         if (is_next_clust(mydata, *dentptr)) {
 359                 /* A new cluster is allocated for directory table */
 360                 flush_dir_table(mydata, dentptr);
 361         }
 362 }
 363
 364 static __u32 dir_curclust;
 365
 366 /*
 367  * Extract the full long filename starting at 'retdent' (which is really
 368  * a slot) into 'l_name'. If successful also copy the real directory entry
 369  * into 'retdent'
 370  * If additional adjacent cluster for directory entries is read into memory,
 371  * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
 372  * the location of the real directory entry is returned by 'retdent'
 373  * Return 0 on success, -1 otherwise.
 374  */
 375 static int
 376 get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
 377               dir_entry **retdent, char *l_name)
 378 {
 379         dir_entry *realdent;
 380         dir_slot *slotptr = (dir_slot *)(*retdent);
 381         dir_slot *slotptr2 = NULL;
 382         __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
 383                                                         PREFETCH_BLOCKS :
 384                                                         mydata->clust_size);
 385         __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
 386         int idx = 0, cur_position = 0;
 387
 388         if (counter > VFAT_MAXSEQ) {
 389                 debug("Error: VFAT name is too long\n");
 390                 return -1;
 391         }
 392
 393         while ((__u8 *)slotptr < buflimit) {
 394                 if (counter == 0)
 395                         break;
 396                 if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
 397                         return -1;
 398                 slotptr++;
 399                 counter--;
 400         }
 401
 402         if ((__u8 *)slotptr >= buflimit) {
 403                 if (curclust == 0)
 404                         return -1;
 405                 curclust = get_fatent_value(mydata, dir_curclust);
 406                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 407                         debug("curclust: 0x%x\n", curclust);
 408                         printf("Invalid FAT entry\n");
 409                         return -1;
 410                 }
 411
 412                 dir_curclust = curclust;
 413
 414                 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
 415                                 mydata->clust_size * mydata->sect_size) != 0) {
 416                         debug("Error: reading directory block\n");
 417                         return -1;
 418                 }
 419
 420                 slotptr2 = (dir_slot *)get_contents_vfatname_block;
 421                 while (counter > 0) {
 422                         if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
 423                             & 0xff) != counter)
 424                                 return -1;
 425                         slotptr2++;
 426                         counter--;
 427                 }
 428
 429                 /* Save the real directory entry */
 430                 realdent = (dir_entry *)slotptr2;
 431                 while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
 432                         slotptr2--;
 433                         slot2str(slotptr2, l_name, &idx);
 434                 }
 435         } else {
 436                 /* Save the real directory entry */
 437                 realdent = (dir_entry *)slotptr;
 438         }
 439
 440         do {
 441                 slotptr--;
 442                 if (slot2str(slotptr, l_name, &idx))
 443                         break;
 444         } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
 445
 446         l_name[idx] = '\0';
 447         if (*l_name == DELETED_FLAG)
 448                 *l_name = '\0';
 449         else if (*l_name == aRING)
 450                 *l_name = DELETED_FLAG;
 451         downcase(l_name);
 452
 453         /* Return the real directory entry */
 454         *retdent = realdent;
 455
 456         if (slotptr2) {
 457                 memcpy(get_dentfromdir_block, get_contents_vfatname_block,
 458                         mydata->clust_size * mydata->sect_size);
 459                 cur_position = (__u8 *)realdent - get_contents_vfatname_block;
 460                 *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
 461         }
 462
 463         return 0;
 464 }
 465
 466 /*
 467  * Set the entry at index 'entry' in a FAT (16/32) table.
 468  */
 469 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 470 {
 471         __u32 bufnum, offset;
 472
 473         switch (mydata->fatsize) {
 474         case 32:
 475                 bufnum = entry / FAT32BUFSIZE;
 476                 offset = entry - bufnum * FAT32BUFSIZE;
 477                 break;
 478         case 16:
 479                 bufnum = entry / FAT16BUFSIZE;
 480                 offset = entry - bufnum * FAT16BUFSIZE;
 481                 break;
 482         default:
 483                 /* Unsupported FAT size */
 484                 return -1;
 485         }
 486
 487         /* Read a new block of FAT entries into the cache. */
 488         if (bufnum != mydata->fatbufnum) {
 489                 int getsize = FATBUFBLOCKS;
 490                 __u8 *bufptr = mydata->fatbuf;
 491                 __u32 fatlength = mydata->fatlength;
 492                 __u32 startblock = bufnum * FATBUFBLOCKS;
 493
 494                 fatlength *= mydata->sect_size;
 495                 startblock += mydata->fat_sect;
 496
 497                 if (getsize > fatlength)
 498                         getsize = fatlength;
 499
 500                 if (mydata->fatbufnum != -1) {
 501                         if (flush_fat_buffer(mydata) < 0)
 502                                 return -1;
 503                 }
 504
 505                 if (disk_read(startblock, getsize, bufptr) < 0) {
 506                         debug("Error reading FAT blocks\n");
 507                         return -1;
 508                 }
 509                 mydata->fatbufnum = bufnum;
 510         }
 511
 512         /* Set the actual entry */
 513         switch (mydata->fatsize) {
 514         case 32:
 515                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 516                 break;
 517         case 16:
 518                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 519                 break;
 520         default:
 521                 return -1;
 522         }
 523
 524         return 0;
 525 }
 526
 527 /*
 528  * Determine the entry value at index 'entry' in a FAT (16/32) table
 529  */
 530 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 531 {
 532         __u32 next_fat, next_entry = entry + 1;
 533
 534         while (1) {
 535                 next_fat = get_fatent_value(mydata, next_entry);
 536                 if (next_fat == 0) {
 537                         set_fatent_value(mydata, entry, next_entry);
 538                         break;
 539                 }
 540                 next_entry++;
 541         }
 542         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 543                mydata->fatsize, entry, next_entry);
 544
 545         return next_entry;
 546 }
 547
 548 /*
 549  * Write at most 'size' bytes from 'buffer' into the specified cluster.
 550  * Return 0 on success, -1 otherwise.
 551  */
 552 static int
 553 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 554              unsigned long size)
 555 {
 556         __u32 idx = 0;
 557         __u32 startsect;
 558         int ret;
 559
 560         if (clustnum > 0)
 561                 startsect = mydata->data_begin +
 562                                 clustnum * mydata->clust_size;
 563         else
 564                 startsect = mydata->rootdir_sect;
 565
 566         debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 567
 568         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 569                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 570
 571                 printf("FAT: Misaligned buffer address (%p)\n", buffer);
 572
 573                 while (size >= mydata->sect_size) {
 574                         memcpy(tmpbuf, buffer, mydata->sect_size);
 575                         ret = disk_write(startsect++, 1, tmpbuf);
 576                         if (ret != 1) {
 577                                 debug("Error writing data (got %d)\n", ret);
 578                                 return -1;
 579                         }
 580
 581                         buffer += mydata->sect_size;
 582                         size -= mydata->sect_size;
 583                 }
 584         } else if (size >= mydata->sect_size) {
 585                 idx = size / mydata->sect_size;
 586                 ret = disk_write(startsect, idx, buffer);
 587                 if (ret != idx) {
 588                         debug("Error writing data (got %d)\n", ret);
 589                         return -1;
 590                 }
 591
 592                 startsect += idx;
 593                 idx *= mydata->sect_size;
 594                 buffer += idx;
 595                 size -= idx;
 596         }
 597
 598         if (size) {
 599                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 600
 601                 memcpy(tmpbuf, buffer, size);
 602                 ret = disk_write(startsect, 1, tmpbuf);
 603                 if (ret != 1) {
 604                         debug("Error writing data (got %d)\n", ret);
 605                         return -1;
 606                 }
 607         }
 608
 609         return 0;
 610 }
 611
 612 /*
 613  * Find the first empty cluster
 614  */
 615 static int find_empty_cluster(fsdata *mydata)
 616 {
 617         __u32 fat_val, entry = 3;
 618
 619         while (1) {
 620                 fat_val = get_fatent_value(mydata, entry);
 621                 if (fat_val == 0)
 622                         break;
 623                 entry++;
 624         }
 625
 626         return entry;
 627 }
 628
 629 /*
 630  * Write directory entries in 'get_dentfromdir_block' to block device
 631  */
 632 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
 633 {
 634         int dir_newclust = 0;
 635
 636         if (set_cluster(mydata, dir_curclust,
 637                     get_dentfromdir_block,
 638                     mydata->clust_size * mydata->sect_size) != 0) {
 639                 printf("error: wrinting directory entry\n");
 640                 return;
 641         }
 642         dir_newclust = find_empty_cluster(mydata);
 643         set_fatent_value(mydata, dir_curclust, dir_newclust);
 644         if (mydata->fatsize == 32)
 645                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 646         else if (mydata->fatsize == 16)
 647                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 648
 649         dir_curclust = dir_newclust;
 650
 651         if (flush_fat_buffer(mydata) < 0)
 652                 return;
 653
 654         memset(get_dentfromdir_block, 0x00,
 655                 mydata->clust_size * mydata->sect_size);
 656
 657         *dentptr = (dir_entry *) get_dentfromdir_block;
 658 }
 659
 660 /*
 661  * Set empty cluster from 'entry' to the end of a file
 662  */
 663 static int clear_fatent(fsdata *mydata, __u32 entry)
 664 {
 665         __u32 fat_val;
 666
 667         while (1) {
 668                 fat_val = get_fatent_value(mydata, entry);
 669                 if (fat_val != 0)
 670                         set_fatent_value(mydata, entry, 0);
 671                 else
 672                         break;
 673
 674                 if (fat_val == 0xfffffff || fat_val == 0xffff)
 675                         break;
 676
 677                 entry = fat_val;
 678         }
 679
 680         /* Flush fat buffer */
 681         if (flush_fat_buffer(mydata) < 0)
 682                 return -1;
 683
 684         return 0;
 685 }
 686
 687 /*
 688  * Write at most 'maxsize' bytes from 'buffer' into
 689  * the file associated with 'dentptr'
 690  * Update the number of bytes written in *gotsize and return 0
 691  * or return -1 on fatal errors.
 692  */
 693 static int
 694 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
 695               loff_t maxsize, loff_t *gotsize)
 696 {
 697         loff_t filesize = FAT2CPU32(dentptr->size);
 698         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 699         __u32 curclust = START(dentptr);
 700         __u32 endclust = 0, newclust = 0;
 701         loff_t actsize;
 702
 703         *gotsize = 0;
 704         debug("Filesize: %llu bytes\n", filesize);
 705
 706         if (maxsize > 0 && filesize > maxsize)
 707                 filesize = maxsize;
 708
 709         debug("%llu bytes\n", filesize);
 710
 711         if (!curclust) {
 712                 if (filesize) {
 713                         debug("error: nonempty clusterless file!\n");
 714                         return -1;
 715                 }
 716                 return 0;
 717         }
 718
 719         actsize = bytesperclust;
 720         endclust = curclust;
 721         do {
 722                 /* search for consecutive clusters */
 723                 while (actsize < filesize) {
 724                         newclust = determine_fatent(mydata, endclust);
 725
 726                         if ((newclust - 1) != endclust)
 727                                 goto getit;
 728
 729                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 730                                 debug("newclust: 0x%x\n", newclust);
 731                                 debug("Invalid FAT entry\n");
 732                                 return 0;
 733                         }
 734                         endclust = newclust;
 735                         actsize += bytesperclust;
 736                 }
 737
 738                 /* set remaining bytes */
 739                 actsize = filesize;
 740                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 741                         debug("error: writing cluster\n");
 742                         return -1;
 743                 }
 744                 *gotsize += actsize;
 745
 746                 /* Mark end of file in FAT */
 747                 if (mydata->fatsize == 16)
 748                         newclust = 0xffff;
 749                 else if (mydata->fatsize == 32)
 750                         newclust = 0xfffffff;
 751                 set_fatent_value(mydata, endclust, newclust);
 752
 753                 return 0;
 754 getit:
 755                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 756                         debug("error: writing cluster\n");
 757                         return -1;
 758                 }
 759                 *gotsize += actsize;
 760                 filesize -= actsize;
 761                 buffer += actsize;
 762
 763                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 764                         debug("newclust: 0x%x\n", newclust);
 765                         debug("Invalid FAT entry\n");
 766                         return 0;
 767                 }
 768                 actsize = bytesperclust;
 769                 curclust = endclust = newclust;
 770         } while (1);
 771 }
 772
 773 /*
 774  * Set start cluster in directory entry
 775  */
 776 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 777                                 __u32 start_cluster)
 778 {
 779         if (mydata->fatsize == 32)
 780                 dentptr->starthi =
 781                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 782         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 783 }
 784
 785 /*
 786  * Fill dir_entry
 787  */
 788 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 789         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 790 {
 791         set_start_cluster(mydata, dentptr, start_cluster);
 792         dentptr->size = cpu_to_le32(size);
 793
 794         dentptr->attr = attr;
 795
 796         set_name(dentptr, filename);
 797 }
 798
 799 /*
 800  * Check whether adding a file makes the file system to
 801  * exceed the size of the block device
 802  * Return -1 when overflow occurs, otherwise return 0
 803  */
 804 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 805 {
 806         __u32 startsect, sect_num, offset;
 807
 808         if (clustnum > 0) {
 809                 startsect = mydata->data_begin +
 810                                 clustnum * mydata->clust_size;
 811         } else {
 812                 startsect = mydata->rootdir_sect;
 813         }
 814
 815         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 816
 817         if (offset != 0)
 818                 sect_num++;
 819
 820         if (startsect + sect_num > cur_part_info.start + total_sector)
 821                 return -1;
 822         return 0;
 823 }
 824
 825 /*
 826  * Check if adding several entries exceed one cluster boundary
 827  */
 828 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
 829 {
 830         int cur_position;
 831
 832         cur_position = (__u8 *)dentptr - get_dentfromdir_block;
 833
 834         if (cur_position >= mydata->clust_size * mydata->sect_size)
 835                 return 1;
 836         else
 837                 return 0;
 838 }
 839
 840 static dir_entry *empty_dentptr;
 841 /*
 842  * Find a directory entry based on filename or start cluster number
 843  * If the directory entry is not found,
 844  * the new position for writing a directory entry will be returned
 845  */
 846 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
 847         char *filename, dir_entry *retdent, __u32 start)
 848 {
 849         __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
 850
 851         debug("get_dentfromdir: %s\n", filename);
 852
 853         while (1) {
 854                 dir_entry *dentptr;
 855
 856                 int i;
 857
 858                 if (get_cluster(mydata, curclust, get_dentfromdir_block,
 859                             mydata->clust_size * mydata->sect_size) != 0) {
 860                         printf("Error: reading directory block\n");
 861                         return NULL;
 862                 }
 863
 864                 dentptr = (dir_entry *)get_dentfromdir_block;
 865
 866                 dir_curclust = curclust;
 867
 868                 for (i = 0; i < DIRENTSPERCLUST; i++) {
 869                         char s_name[14], l_name[VFAT_MAXLEN_BYTES];
 870
 871                         l_name[0] = '\0';
 872                         if (dentptr->name[0] == DELETED_FLAG) {
 873                                 dentptr++;
 874                                 if (is_next_clust(mydata, dentptr))
 875                                         break;
 876                                 continue;
 877                         }
 878                         if ((dentptr->attr & ATTR_VOLUME)) {
 879                                 if (vfat_enabled &&
 880                                     (dentptr->attr & ATTR_VFAT) &&
 881                                     (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
 882                                         get_long_file_name(mydata, curclust,
 883                                                      get_dentfromdir_block,
 884                                                      &dentptr, l_name);
 885                                         debug("vfatname: |%s|\n", l_name);
 886                                 } else {
 887                                         /* Volume label or VFAT entry */
 888                                         dentptr++;
 889                                         if (is_next_clust(mydata, dentptr))
 890                                                 break;
 891                                         continue;
 892                                 }
 893                         }
 894                         if (dentptr->name[0] == 0) {
 895                                 debug("Dentname == NULL - %d\n", i);
 896                                 empty_dentptr = dentptr;
 897                                 return NULL;
 898                         }
 899
 900                         get_name(dentptr, s_name);
 901
 902                         if (strcmp(filename, s_name)
 903                             && strcmp(filename, l_name)) {
 904                                 debug("Mismatch: |%s|%s|\n",
 905                                         s_name, l_name);
 906                                 dentptr++;
 907                                 if (is_next_clust(mydata, dentptr))
 908                                         break;
 909                                 continue;
 910                         }
 911
 912                         memcpy(retdent, dentptr, sizeof(dir_entry));
 913
 914                         debug("DentName: %s", s_name);
 915                         debug(", start: 0x%x", START(dentptr));
 916                         debug(", size:  0x%x %s\n",
 917                               FAT2CPU32(dentptr->size),
 918                               (dentptr->attr & ATTR_DIR) ?
 919                               "(DIR)" : "");
 920
 921                         return dentptr;
 922                 }
 923
 924                 /*
 925                  * In FAT16/12, the root dir is locate before data area, shows
 926                  * in following:
 927                  * -------------------------------------------------------------
 928                  * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
 929                  * -------------------------------------------------------------
 930                  *
 931                  * As a result if curclust is in Root dir, it is a negative
 932                  * number or 0, 1.
 933                  *
 934                  */
 935                 if (mydata->fatsize != 32 && (int)curclust <= 1) {
 936                         /* Current clust is in root dir, set to next clust */
 937                         curclust++;
 938                         if ((int)curclust <= 1)
 939                                 continue;       /* continue to find */
 940
 941                         /* Reach the end of root dir */
 942                         empty_dentptr = dentptr;
 943                         return NULL;
 944                 }
 945
 946                 curclust = get_fatent_value(mydata, dir_curclust);
 947                 if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 948                         empty_dentptr = dentptr;
 949                         return NULL;
 950                 }
 951                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 952                         debug("curclust: 0x%x\n", curclust);
 953                         debug("Invalid FAT entry\n");
 954                         return NULL;
 955                 }
 956         }
 957
 958         return NULL;
 959 }
 960
 961 static int do_fat_write(const char *filename, void *buffer, loff_t size,
 962                         loff_t *actwrite)
 963 {
 964         dir_entry *dentptr, *retdent;
 965         __u32 startsect;
 966         __u32 start_cluster;
 967         boot_sector bs;
 968         volume_info volinfo;
 969         fsdata datablock;
 970         fsdata *mydata = &datablock;
 971         int cursect;
 972         int ret = -1, name_len;
 973         char l_filename[VFAT_MAXLEN_BYTES];
 974
 975         *actwrite = size;
 976         dir_curclust = 0;
 977
 978         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 979                 debug("error: reading boot sector\n");
 980                 return -1;
 981         }
 982
 983         total_sector = bs.total_sect;
 984         if (total_sector == 0)
 985                 total_sector = (int)cur_part_info.size; /* cast of lbaint_t */
 986
 987         if (mydata->fatsize == 32)
 988                 mydata->fatlength = bs.fat32_length;
 989         else
 990                 mydata->fatlength = bs.fat_length;
 991
 992         mydata->fat_sect = bs.reserved;
 993
 994         cursect = mydata->rootdir_sect
 995                 = mydata->fat_sect + mydata->fatlength * bs.fats;
 996         num_of_fats = bs.fats;
 997
 998         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
 999         mydata->clust_size = bs.cluster_size;
1000
1001         if (mydata->fatsize == 32) {
1002                 mydata->data_begin = mydata->rootdir_sect -
1003                                         (mydata->clust_size * 2);
1004         } else {
1005                 int rootdir_size;
1006
1007                 rootdir_size = ((bs.dir_entries[1]  * (int)256 +
1008                                  bs.dir_entries[0]) *
1009                                  sizeof(dir_entry)) /
1010                                  mydata->sect_size;
1011                 mydata->data_begin = mydata->rootdir_sect +
1012                                         rootdir_size -
1013                                         (mydata->clust_size * 2);
1014         }
1015
1016         mydata->fatbufnum = -1;
1017         mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
1018         if (mydata->fatbuf == NULL) {
1019                 debug("Error: allocating memory\n");
1020                 return -1;
1021         }
1022
1023         if (disk_read(cursect,
1024                 (mydata->fatsize == 32) ?
1025                 (mydata->clust_size) :
1026                 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
1027                 debug("Error: reading rootdir block\n");
1028                 goto exit;
1029         }
1030         dentptr = (dir_entry *) do_fat_read_at_block;
1031
1032         name_len = strlen(filename);
1033         if (name_len >= VFAT_MAXLEN_BYTES)
1034                 name_len = VFAT_MAXLEN_BYTES - 1;
1035
1036         memcpy(l_filename, filename, name_len);
1037         l_filename[name_len] = 0; /* terminate the string */
1038         downcase(l_filename);
1039
1040         startsect = mydata->rootdir_sect;
1041         retdent = find_directory_entry(mydata, startsect,
1042                                 l_filename, dentptr, 0);
1043         if (retdent) {
1044                 /* Update file size and start_cluster in a directory entry */
1045                 retdent->size = cpu_to_le32(size);
1046                 start_cluster = START(retdent);
1047
1048                 if (start_cluster) {
1049                         if (size) {
1050                                 ret = check_overflow(mydata, start_cluster,
1051                                                         size);
1052                                 if (ret) {
1053                                         printf("Error: %llu overflow\n", size);
1054                                         goto exit;
1055                                 }
1056                         }
1057
1058                         ret = clear_fatent(mydata, start_cluster);
1059                         if (ret) {
1060                                 printf("Error: clearing FAT entries\n");
1061                                 goto exit;
1062                         }
1063
1064                         if (!size)
1065                                 set_start_cluster(mydata, retdent, 0);
1066                 } else if (size) {
1067                         ret = start_cluster = find_empty_cluster(mydata);
1068                         if (ret < 0) {
1069                                 printf("Error: finding empty cluster\n");
1070                                 goto exit;
1071                         }
1072
1073                         ret = check_overflow(mydata, start_cluster, size);
1074                         if (ret) {
1075                                 printf("Error: %llu overflow\n", size);
1076                                 goto exit;
1077                         }
1078
1079                         set_start_cluster(mydata, retdent, start_cluster);
1080                 }
1081         } else {
1082                 /* Set short name to set alias checksum field in dir_slot */
1083                 set_name(empty_dentptr, filename);
1084                 fill_dir_slot(mydata, &empty_dentptr, filename);
1085
1086                 if (size) {
1087                         ret = start_cluster = find_empty_cluster(mydata);
1088                         if (ret < 0) {
1089                                 printf("Error: finding empty cluster\n");
1090                                 goto exit;
1091                         }
1092
1093                         ret = check_overflow(mydata, start_cluster, size);
1094                         if (ret) {
1095                                 printf("Error: %llu overflow\n", size);
1096                                 goto exit;
1097                         }
1098                 } else {
1099                         start_cluster = 0;
1100                 }
1101
1102                 /* Set attribute as archieve for regular file */
1103                 fill_dentry(mydata, empty_dentptr, filename,
1104                         start_cluster, size, 0x20);
1105
1106                 retdent = empty_dentptr;
1107         }
1108
1109         ret = set_contents(mydata, retdent, buffer, size, actwrite);
1110         if (ret < 0) {
1111                 printf("Error: writing contents\n");
1112                 goto exit;
1113         }
1114         debug("attempt to write 0x%llx bytes\n", *actwrite);
1115
1116         /* Flush fat buffer */
1117         ret = flush_fat_buffer(mydata);
1118         if (ret) {
1119                 printf("Error: flush fat buffer\n");
1120                 goto exit;
1121         }
1122
1123         /* Write directory table to device */
1124         ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
1125                         mydata->clust_size * mydata->sect_size);
1126         if (ret)
1127                 printf("Error: writing directory entry\n");
1128
1129 exit:
1130         free(mydata->fatbuf);
1131         return ret;
1132 }
1133
1134 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1135                    loff_t maxsize, loff_t *actwrite)
1136 {
1137         if (offset != 0) {
1138                 printf("Error: non zero offset is currently not suported.\n");
1139                 return -1;
1140         }
1141
1142         printf("writing %s\n", filename);
1143         return do_fat_write(filename, buffer, maxsize, actwrite);
1144 }