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 || !cur_dev->block_write)
  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 = cur_dev->block_write(cur_dev->dev,
  45                                    cur_part_info.start + block,
  46                                    nr_blocks, buf);
  47         if (nr_blocks && ret == 0)
  48                 return -1;
  49
  50         return ret;
  51 }
  52
  53 /*
  54  * Set short name in directory entry
  55  */
  56 static void set_name(dir_entry *dirent, const char *filename)
  57 {
  58         char s_name[VFAT_MAXLEN_BYTES];
  59         char *period;
  60         int period_location, len, i, ext_num;
  61
  62         if (filename == NULL)
  63                 return;
  64
  65         len = strlen(filename);
  66         if (len == 0)
  67                 return;
  68
  69         strcpy(s_name, filename);
  70         uppercase(s_name, len);
  71
  72         period = strchr(s_name, '.');
  73         if (period == NULL) {
  74                 period_location = len;
  75                 ext_num = 0;
  76         } else {
  77                 period_location = period - s_name;
  78                 ext_num = len - period_location - 1;
  79         }
  80
  81         /* Pad spaces when the length of file name is shorter than eight */
  82         if (period_location < 8) {
  83                 memcpy(dirent->name, s_name, period_location);
  84                 for (i = period_location; i < 8; i++)
  85                         dirent->name[i] = ' ';
  86         } else if (period_location == 8) {
  87                 memcpy(dirent->name, s_name, period_location);
  88         } else {
  89                 memcpy(dirent->name, s_name, 6);
  90                 dirent->name[6] = '~';
  91                 dirent->name[7] = '1';
  92         }
  93
  94         if (ext_num < 3) {
  95                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
  96                 for (i = ext_num; i < 3; i++)
  97                         dirent->ext[i] = ' ';
  98         } else
  99                 memcpy(dirent->ext, s_name + period_location + 1, 3);
 100
 101         debug("name : %s\n", dirent->name);
 102         debug("ext : %s\n", dirent->ext);
 103 }
 104
 105 static __u8 num_of_fats;
 106 /*
 107  * Write fat buffer into block device
 108  */
 109 static int flush_fat_buffer(fsdata *mydata)
 110 {
 111         int getsize = FATBUFBLOCKS;
 112         __u32 fatlength = mydata->fatlength;
 113         __u8 *bufptr = mydata->fatbuf;
 114         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 115
 116         startblock += mydata->fat_sect;
 117
 118         if (getsize > fatlength)
 119                 getsize = fatlength;
 120
 121         /* Write FAT buf */
 122         if (disk_write(startblock, getsize, bufptr) < 0) {
 123                 debug("error: writing FAT blocks\n");
 124                 return -1;
 125         }
 126
 127         if (num_of_fats == 2) {
 128                 /* Update corresponding second FAT blocks */
 129                 startblock += mydata->fatlength;
 130                 if (disk_write(startblock, getsize, bufptr) < 0) {
 131                         debug("error: writing second FAT blocks\n");
 132                         return -1;
 133                 }
 134         }
 135
 136         return 0;
 137 }
 138
 139 /*
 140  * Get the entry at index 'entry' in a FAT (12/16/32) table.
 141  * On failure 0x00 is returned.
 142  * When bufnum is changed, write back the previous fatbuf to the disk.
 143  */
 144 static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
 145 {
 146         __u32 bufnum;
 147         __u32 off16, offset;
 148         __u32 ret = 0x00;
 149         __u16 val1, val2;
 150
 151         if (CHECK_CLUST(entry, mydata->fatsize)) {
 152                 printf("Error: Invalid FAT entry: 0x%08x\n", entry);
 153                 return ret;
 154         }
 155
 156         switch (mydata->fatsize) {
 157         case 32:
 158                 bufnum = entry / FAT32BUFSIZE;
 159                 offset = entry - bufnum * FAT32BUFSIZE;
 160                 break;
 161         case 16:
 162                 bufnum = entry / FAT16BUFSIZE;
 163                 offset = entry - bufnum * FAT16BUFSIZE;
 164                 break;
 165         case 12:
 166                 bufnum = entry / FAT12BUFSIZE;
 167                 offset = entry - bufnum * FAT12BUFSIZE;
 168                 break;
 169
 170         default:
 171                 /* Unsupported FAT size */
 172                 return ret;
 173         }
 174
 175         debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
 176                mydata->fatsize, entry, entry, offset, offset);
 177
 178         /* Read a new block of FAT entries into the cache. */
 179         if (bufnum != mydata->fatbufnum) {
 180                 int getsize = FATBUFBLOCKS;
 181                 __u8 *bufptr = mydata->fatbuf;
 182                 __u32 fatlength = mydata->fatlength;
 183                 __u32 startblock = bufnum * FATBUFBLOCKS;
 184
 185                 if (getsize > fatlength)
 186                         getsize = fatlength;
 187
 188                 fatlength *= mydata->sect_size; /* We want it in bytes now */
 189                 startblock += mydata->fat_sect; /* Offset from start of disk */
 190
 191                 /* Write back the fatbuf to the disk */
 192                 if (mydata->fatbufnum != -1) {
 193                         if (flush_fat_buffer(mydata) < 0)
 194                                 return -1;
 195                 }
 196
 197                 if (disk_read(startblock, getsize, bufptr) < 0) {
 198                         debug("Error reading FAT blocks\n");
 199                         return ret;
 200                 }
 201                 mydata->fatbufnum = bufnum;
 202         }
 203
 204         /* Get the actual entry from the table */
 205         switch (mydata->fatsize) {
 206         case 32:
 207                 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
 208                 break;
 209         case 16:
 210                 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
 211                 break;
 212         case 12:
 213                 off16 = (offset * 3) / 4;
 214
 215                 switch (offset & 0x3) {
 216                 case 0:
 217                         ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
 218                         ret &= 0xfff;
 219                         break;
 220                 case 1:
 221                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 222                         val1 &= 0xf000;
 223                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 224                         val2 &= 0x00ff;
 225                         ret = (val2 << 4) | (val1 >> 12);
 226                         break;
 227                 case 2:
 228                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 229                         val1 &= 0xff00;
 230                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 231                         val2 &= 0x000f;
 232                         ret = (val2 << 8) | (val1 >> 8);
 233                         break;
 234                 case 3:
 235                         ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 236                         ret = (ret & 0xfff0) >> 4;
 237                         break;
 238                 default:
 239                         break;
 240                 }
 241                 break;
 242         }
 243         debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
 244                mydata->fatsize, ret, entry, offset);
 245
 246         return ret;
 247 }
 248
 249 /*
 250  * Set the file name information from 'name' into 'slotptr',
 251  */
 252 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 253 {
 254         int j, end_idx = 0;
 255
 256         for (j = 0; j <= 8; j += 2) {
 257                 if (name[*idx] == 0x00) {
 258                         slotptr->name0_4[j] = 0;
 259                         slotptr->name0_4[j + 1] = 0;
 260                         end_idx++;
 261                         goto name0_4;
 262                 }
 263                 slotptr->name0_4[j] = name[*idx];
 264                 (*idx)++;
 265                 end_idx++;
 266         }
 267         for (j = 0; j <= 10; j += 2) {
 268                 if (name[*idx] == 0x00) {
 269                         slotptr->name5_10[j] = 0;
 270                         slotptr->name5_10[j + 1] = 0;
 271                         end_idx++;
 272                         goto name5_10;
 273                 }
 274                 slotptr->name5_10[j] = name[*idx];
 275                 (*idx)++;
 276                 end_idx++;
 277         }
 278         for (j = 0; j <= 2; j += 2) {
 279                 if (name[*idx] == 0x00) {
 280                         slotptr->name11_12[j] = 0;
 281                         slotptr->name11_12[j + 1] = 0;
 282                         end_idx++;
 283                         goto name11_12;
 284                 }
 285                 slotptr->name11_12[j] = name[*idx];
 286                 (*idx)++;
 287                 end_idx++;
 288         }
 289
 290         if (name[*idx] == 0x00)
 291                 return 1;
 292
 293         return 0;
 294 /* Not used characters are filled with 0xff 0xff */
 295 name0_4:
 296         for (; end_idx < 5; end_idx++) {
 297                 slotptr->name0_4[end_idx * 2] = 0xff;
 298                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 299         }
 300         end_idx = 5;
 301 name5_10:
 302         end_idx -= 5;
 303         for (; end_idx < 6; end_idx++) {
 304                 slotptr->name5_10[end_idx * 2] = 0xff;
 305                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 306         }
 307         end_idx = 11;
 308 name11_12:
 309         end_idx -= 11;
 310         for (; end_idx < 2; end_idx++) {
 311                 slotptr->name11_12[end_idx * 2] = 0xff;
 312                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 313         }
 314
 315         return 1;
 316 }
 317
 318 static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
 319 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
 320
 321 /*
 322  * Fill dir_slot entries with appropriate name, id, and attr
 323  * The real directory entry is returned by 'dentptr'
 324  */
 325 static void
 326 fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
 327 {
 328         dir_slot *slotptr = (dir_slot *)get_contents_vfatname_block;
 329         __u8 counter = 0, checksum;
 330         int idx = 0, ret;
 331         char s_name[16];
 332
 333         /* Get short file name and checksum value */
 334         strncpy(s_name, (*dentptr)->name, 16);
 335         checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
 336
 337         do {
 338                 memset(slotptr, 0x00, sizeof(dir_slot));
 339                 ret = str2slot(slotptr, l_name, &idx);
 340                 slotptr->id = ++counter;
 341                 slotptr->attr = ATTR_VFAT;
 342                 slotptr->alias_checksum = checksum;
 343                 slotptr++;
 344         } while (ret == 0);
 345
 346         slotptr--;
 347         slotptr->id |= LAST_LONG_ENTRY_MASK;
 348
 349         while (counter >= 1) {
 350                 if (is_next_clust(mydata, *dentptr)) {
 351                         /* A new cluster is allocated for directory table */
 352                         flush_dir_table(mydata, dentptr);
 353                 }
 354                 memcpy(*dentptr, slotptr, sizeof(dir_slot));
 355                 (*dentptr)++;
 356                 slotptr--;
 357                 counter--;
 358         }
 359
 360         if (is_next_clust(mydata, *dentptr)) {
 361                 /* A new cluster is allocated for directory table */
 362                 flush_dir_table(mydata, dentptr);
 363         }
 364 }
 365
 366 static __u32 dir_curclust;
 367
 368 /*
 369  * Extract the full long filename starting at 'retdent' (which is really
 370  * a slot) into 'l_name'. If successful also copy the real directory entry
 371  * into 'retdent'
 372  * If additional adjacent cluster for directory entries is read into memory,
 373  * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
 374  * the location of the real directory entry is returned by 'retdent'
 375  * Return 0 on success, -1 otherwise.
 376  */
 377 static int
 378 get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
 379               dir_entry **retdent, char *l_name)
 380 {
 381         dir_entry *realdent;
 382         dir_slot *slotptr = (dir_slot *)(*retdent);
 383         dir_slot *slotptr2 = NULL;
 384         __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
 385                                                         PREFETCH_BLOCKS :
 386                                                         mydata->clust_size);
 387         __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
 388         int idx = 0, cur_position = 0;
 389
 390         if (counter > VFAT_MAXSEQ) {
 391                 debug("Error: VFAT name is too long\n");
 392                 return -1;
 393         }
 394
 395         while ((__u8 *)slotptr < buflimit) {
 396                 if (counter == 0)
 397                         break;
 398                 if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
 399                         return -1;
 400                 slotptr++;
 401                 counter--;
 402         }
 403
 404         if ((__u8 *)slotptr >= buflimit) {
 405                 if (curclust == 0)
 406                         return -1;
 407                 curclust = get_fatent_value(mydata, dir_curclust);
 408                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 409                         debug("curclust: 0x%x\n", curclust);
 410                         printf("Invalid FAT entry\n");
 411                         return -1;
 412                 }
 413
 414                 dir_curclust = curclust;
 415
 416                 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
 417                                 mydata->clust_size * mydata->sect_size) != 0) {
 418                         debug("Error: reading directory block\n");
 419                         return -1;
 420                 }
 421
 422                 slotptr2 = (dir_slot *)get_contents_vfatname_block;
 423                 while (counter > 0) {
 424                         if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
 425                             & 0xff) != counter)
 426                                 return -1;
 427                         slotptr2++;
 428                         counter--;
 429                 }
 430
 431                 /* Save the real directory entry */
 432                 realdent = (dir_entry *)slotptr2;
 433                 while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
 434                         slotptr2--;
 435                         slot2str(slotptr2, l_name, &idx);
 436                 }
 437         } else {
 438                 /* Save the real directory entry */
 439                 realdent = (dir_entry *)slotptr;
 440         }
 441
 442         do {
 443                 slotptr--;
 444                 if (slot2str(slotptr, l_name, &idx))
 445                         break;
 446         } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
 447
 448         l_name[idx] = '\0';
 449         if (*l_name == DELETED_FLAG)
 450                 *l_name = '\0';
 451         else if (*l_name == aRING)
 452                 *l_name = DELETED_FLAG;
 453         downcase(l_name);
 454
 455         /* Return the real directory entry */
 456         *retdent = realdent;
 457
 458         if (slotptr2) {
 459                 memcpy(get_dentfromdir_block, get_contents_vfatname_block,
 460                         mydata->clust_size * mydata->sect_size);
 461                 cur_position = (__u8 *)realdent - get_contents_vfatname_block;
 462                 *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
 463         }
 464
 465         return 0;
 466 }
 467
 468 /*
 469  * Set the entry at index 'entry' in a FAT (16/32) table.
 470  */
 471 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 472 {
 473         __u32 bufnum, offset;
 474
 475         switch (mydata->fatsize) {
 476         case 32:
 477                 bufnum = entry / FAT32BUFSIZE;
 478                 offset = entry - bufnum * FAT32BUFSIZE;
 479                 break;
 480         case 16:
 481                 bufnum = entry / FAT16BUFSIZE;
 482                 offset = entry - bufnum * FAT16BUFSIZE;
 483                 break;
 484         default:
 485                 /* Unsupported FAT size */
 486                 return -1;
 487         }
 488
 489         /* Read a new block of FAT entries into the cache. */
 490         if (bufnum != mydata->fatbufnum) {
 491                 int getsize = FATBUFBLOCKS;
 492                 __u8 *bufptr = mydata->fatbuf;
 493                 __u32 fatlength = mydata->fatlength;
 494                 __u32 startblock = bufnum * FATBUFBLOCKS;
 495
 496                 fatlength *= mydata->sect_size;
 497                 startblock += mydata->fat_sect;
 498
 499                 if (getsize > fatlength)
 500                         getsize = fatlength;
 501
 502                 if (mydata->fatbufnum != -1) {
 503                         if (flush_fat_buffer(mydata) < 0)
 504                                 return -1;
 505                 }
 506
 507                 if (disk_read(startblock, getsize, bufptr) < 0) {
 508                         debug("Error reading FAT blocks\n");
 509                         return -1;
 510                 }
 511                 mydata->fatbufnum = bufnum;
 512         }
 513
 514         /* Set the actual entry */
 515         switch (mydata->fatsize) {
 516         case 32:
 517                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 518                 break;
 519         case 16:
 520                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 521                 break;
 522         default:
 523                 return -1;
 524         }
 525
 526         return 0;
 527 }
 528
 529 /*
 530  * Determine the entry value at index 'entry' in a FAT (16/32) table
 531  */
 532 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 533 {
 534         __u32 next_fat, next_entry = entry + 1;
 535
 536         while (1) {
 537                 next_fat = get_fatent_value(mydata, next_entry);
 538                 if (next_fat == 0) {
 539                         set_fatent_value(mydata, entry, next_entry);
 540                         break;
 541                 }
 542                 next_entry++;
 543         }
 544         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 545                mydata->fatsize, entry, next_entry);
 546
 547         return next_entry;
 548 }
 549
 550 /*
 551  * Write at most 'size' bytes from 'buffer' into the specified cluster.
 552  * Return 0 on success, -1 otherwise.
 553  */
 554 static int
 555 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 556              unsigned long size)
 557 {
 558         __u32 idx = 0;
 559         __u32 startsect;
 560         int ret;
 561
 562         if (clustnum > 0)
 563                 startsect = mydata->data_begin +
 564                                 clustnum * mydata->clust_size;
 565         else
 566                 startsect = mydata->rootdir_sect;
 567
 568         debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 569
 570         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 571                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 572
 573                 printf("FAT: Misaligned buffer address (%p)\n", buffer);
 574
 575                 while (size >= mydata->sect_size) {
 576                         memcpy(tmpbuf, buffer, mydata->sect_size);
 577                         ret = disk_write(startsect++, 1, tmpbuf);
 578                         if (ret != 1) {
 579                                 debug("Error writing data (got %d)\n", ret);
 580                                 return -1;
 581                         }
 582
 583                         buffer += mydata->sect_size;
 584                         size -= mydata->sect_size;
 585                 }
 586         } else if (size >= mydata->sect_size) {
 587                 idx = size / mydata->sect_size;
 588                 ret = disk_write(startsect, idx, buffer);
 589                 if (ret != idx) {
 590                         debug("Error writing data (got %d)\n", ret);
 591                         return -1;
 592                 }
 593
 594                 startsect += idx;
 595                 idx *= mydata->sect_size;
 596                 buffer += idx;
 597                 size -= idx;
 598         }
 599
 600         if (size) {
 601                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 602
 603                 memcpy(tmpbuf, buffer, size);
 604                 ret = disk_write(startsect, 1, tmpbuf);
 605                 if (ret != 1) {
 606                         debug("Error writing data (got %d)\n", ret);
 607                         return -1;
 608                 }
 609         }
 610
 611         return 0;
 612 }
 613
 614 /*
 615  * Find the first empty cluster
 616  */
 617 static int find_empty_cluster(fsdata *mydata)
 618 {
 619         __u32 fat_val, entry = 3;
 620
 621         while (1) {
 622                 fat_val = get_fatent_value(mydata, entry);
 623                 if (fat_val == 0)
 624                         break;
 625                 entry++;
 626         }
 627
 628         return entry;
 629 }
 630
 631 /*
 632  * Write directory entries in 'get_dentfromdir_block' to block device
 633  */
 634 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
 635 {
 636         int dir_newclust = 0;
 637
 638         if (set_cluster(mydata, dir_curclust,
 639                     get_dentfromdir_block,
 640                     mydata->clust_size * mydata->sect_size) != 0) {
 641                 printf("error: wrinting directory entry\n");
 642                 return;
 643         }
 644         dir_newclust = find_empty_cluster(mydata);
 645         set_fatent_value(mydata, dir_curclust, dir_newclust);
 646         if (mydata->fatsize == 32)
 647                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 648         else if (mydata->fatsize == 16)
 649                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 650
 651         dir_curclust = dir_newclust;
 652
 653         if (flush_fat_buffer(mydata) < 0)
 654                 return;
 655
 656         memset(get_dentfromdir_block, 0x00,
 657                 mydata->clust_size * mydata->sect_size);
 658
 659         *dentptr = (dir_entry *) get_dentfromdir_block;
 660 }
 661
 662 /*
 663  * Set empty cluster from 'entry' to the end of a file
 664  */
 665 static int clear_fatent(fsdata *mydata, __u32 entry)
 666 {
 667         __u32 fat_val;
 668
 669         while (1) {
 670                 fat_val = get_fatent_value(mydata, entry);
 671                 if (fat_val != 0)
 672                         set_fatent_value(mydata, entry, 0);
 673                 else
 674                         break;
 675
 676                 if (fat_val == 0xfffffff || fat_val == 0xffff)
 677                         break;
 678
 679                 entry = fat_val;
 680         }
 681
 682         /* Flush fat buffer */
 683         if (flush_fat_buffer(mydata) < 0)
 684                 return -1;
 685
 686         return 0;
 687 }
 688
 689 /*
 690  * Write at most 'maxsize' bytes from 'buffer' into
 691  * the file associated with 'dentptr'
 692  * Update the number of bytes written in *gotsize and return 0
 693  * or return -1 on fatal errors.
 694  */
 695 static int
 696 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
 697               loff_t maxsize, loff_t *gotsize)
 698 {
 699         loff_t filesize = FAT2CPU32(dentptr->size);
 700         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 701         __u32 curclust = START(dentptr);
 702         __u32 endclust = 0, newclust = 0;
 703         loff_t actsize;
 704
 705         *gotsize = 0;
 706         debug("Filesize: %llu bytes\n", filesize);
 707
 708         if (maxsize > 0 && filesize > maxsize)
 709                 filesize = maxsize;
 710
 711         debug("%llu bytes\n", filesize);
 712
 713         if (!curclust) {
 714                 if (filesize) {
 715                         debug("error: nonempty clusterless file!\n");
 716                         return -1;
 717                 }
 718                 return 0;
 719         }
 720
 721         actsize = bytesperclust;
 722         endclust = curclust;
 723         do {
 724                 /* search for consecutive clusters */
 725                 while (actsize < filesize) {
 726                         newclust = determine_fatent(mydata, endclust);
 727
 728                         if ((newclust - 1) != endclust)
 729                                 goto getit;
 730
 731                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 732                                 debug("newclust: 0x%x\n", newclust);
 733                                 debug("Invalid FAT entry\n");
 734                                 return 0;
 735                         }
 736                         endclust = newclust;
 737                         actsize += bytesperclust;
 738                 }
 739
 740                 /* set remaining bytes */
 741                 actsize = filesize;
 742                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 743                         debug("error: writing cluster\n");
 744                         return -1;
 745                 }
 746                 *gotsize += actsize;
 747
 748                 /* Mark end of file in FAT */
 749                 if (mydata->fatsize == 16)
 750                         newclust = 0xffff;
 751                 else if (mydata->fatsize == 32)
 752                         newclust = 0xfffffff;
 753                 set_fatent_value(mydata, endclust, newclust);
 754
 755                 return 0;
 756 getit:
 757                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 758                         debug("error: writing cluster\n");
 759                         return -1;
 760                 }
 761                 *gotsize += actsize;
 762                 filesize -= actsize;
 763                 buffer += actsize;
 764
 765                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 766                         debug("newclust: 0x%x\n", newclust);
 767                         debug("Invalid FAT entry\n");
 768                         return 0;
 769                 }
 770                 actsize = bytesperclust;
 771                 curclust = endclust = newclust;
 772         } while (1);
 773 }
 774
 775 /*
 776  * Set start cluster in directory entry
 777  */
 778 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 779                                 __u32 start_cluster)
 780 {
 781         if (mydata->fatsize == 32)
 782                 dentptr->starthi =
 783                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 784         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 785 }
 786
 787 /*
 788  * Fill dir_entry
 789  */
 790 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 791         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 792 {
 793         set_start_cluster(mydata, dentptr, start_cluster);
 794         dentptr->size = cpu_to_le32(size);
 795
 796         dentptr->attr = attr;
 797
 798         set_name(dentptr, filename);
 799 }
 800
 801 /*
 802  * Check whether adding a file makes the file system to
 803  * exceed the size of the block device
 804  * Return -1 when overflow occurs, otherwise return 0
 805  */
 806 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 807 {
 808         __u32 startsect, sect_num, offset;
 809
 810         if (clustnum > 0) {
 811                 startsect = mydata->data_begin +
 812                                 clustnum * mydata->clust_size;
 813         } else {
 814                 startsect = mydata->rootdir_sect;
 815         }
 816
 817         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 818
 819         if (offset != 0)
 820                 sect_num++;
 821
 822         if (startsect + sect_num > cur_part_info.start + total_sector)
 823                 return -1;
 824         return 0;
 825 }
 826
 827 /*
 828  * Check if adding several entries exceed one cluster boundary
 829  */
 830 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
 831 {
 832         int cur_position;
 833
 834         cur_position = (__u8 *)dentptr - get_dentfromdir_block;
 835
 836         if (cur_position >= mydata->clust_size * mydata->sect_size)
 837                 return 1;
 838         else
 839                 return 0;
 840 }
 841
 842 static dir_entry *empty_dentptr;
 843 /*
 844  * Find a directory entry based on filename or start cluster number
 845  * If the directory entry is not found,
 846  * the new position for writing a directory entry will be returned
 847  */
 848 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
 849         char *filename, dir_entry *retdent, __u32 start)
 850 {
 851         __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
 852
 853         debug("get_dentfromdir: %s\n", filename);
 854
 855         while (1) {
 856                 dir_entry *dentptr;
 857
 858                 int i;
 859
 860                 if (get_cluster(mydata, curclust, get_dentfromdir_block,
 861                             mydata->clust_size * mydata->sect_size) != 0) {
 862                         printf("Error: reading directory block\n");
 863                         return NULL;
 864                 }
 865
 866                 dentptr = (dir_entry *)get_dentfromdir_block;
 867
 868                 dir_curclust = curclust;
 869
 870                 for (i = 0; i < DIRENTSPERCLUST; i++) {
 871                         char s_name[14], l_name[VFAT_MAXLEN_BYTES];
 872
 873                         l_name[0] = '\0';
 874                         if (dentptr->name[0] == DELETED_FLAG) {
 875                                 dentptr++;
 876                                 if (is_next_clust(mydata, dentptr))
 877                                         break;
 878                                 continue;
 879                         }
 880                         if ((dentptr->attr & ATTR_VOLUME)) {
 881                                 if (vfat_enabled &&
 882                                     (dentptr->attr & ATTR_VFAT) &&
 883                                     (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
 884                                         get_long_file_name(mydata, curclust,
 885                                                      get_dentfromdir_block,
 886                                                      &dentptr, l_name);
 887                                         debug("vfatname: |%s|\n", l_name);
 888                                 } else {
 889                                         /* Volume label or VFAT entry */
 890                                         dentptr++;
 891                                         if (is_next_clust(mydata, dentptr))
 892                                                 break;
 893                                         continue;
 894                                 }
 895                         }
 896                         if (dentptr->name[0] == 0) {
 897                                 debug("Dentname == NULL - %d\n", i);
 898                                 empty_dentptr = dentptr;
 899                                 return NULL;
 900                         }
 901
 902                         get_name(dentptr, s_name);
 903
 904                         if (strcmp(filename, s_name)
 905                             && strcmp(filename, l_name)) {
 906                                 debug("Mismatch: |%s|%s|\n",
 907                                         s_name, l_name);
 908                                 dentptr++;
 909                                 if (is_next_clust(mydata, dentptr))
 910                                         break;
 911                                 continue;
 912                         }
 913
 914                         memcpy(retdent, dentptr, sizeof(dir_entry));
 915
 916                         debug("DentName: %s", s_name);
 917                         debug(", start: 0x%x", START(dentptr));
 918                         debug(", size:  0x%x %s\n",
 919                               FAT2CPU32(dentptr->size),
 920                               (dentptr->attr & ATTR_DIR) ?
 921                               "(DIR)" : "");
 922
 923                         return dentptr;
 924                 }
 925
 926                 /*
 927                  * In FAT16/12, the root dir is locate before data area, shows
 928                  * in following:
 929                  * -------------------------------------------------------------
 930                  * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
 931                  * -------------------------------------------------------------
 932                  *
 933                  * As a result if curclust is in Root dir, it is a negative
 934                  * number or 0, 1.
 935                  *
 936                  */
 937                 if (mydata->fatsize != 32 && (int)curclust <= 1) {
 938                         /* Current clust is in root dir, set to next clust */
 939                         curclust++;
 940                         if ((int)curclust <= 1)
 941                                 continue;       /* continue to find */
 942
 943                         /* Reach the end of root dir */
 944                         empty_dentptr = dentptr;
 945                         return NULL;
 946                 }
 947
 948                 curclust = get_fatent_value(mydata, dir_curclust);
 949                 if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 950                         empty_dentptr = dentptr;
 951                         return NULL;
 952                 }
 953                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 954                         debug("curclust: 0x%x\n", curclust);
 955                         debug("Invalid FAT entry\n");
 956                         return NULL;
 957                 }
 958         }
 959
 960         return NULL;
 961 }
 962
 963 static int do_fat_write(const char *filename, void *buffer, loff_t size,
 964                         loff_t *actwrite)
 965 {
 966         dir_entry *dentptr, *retdent;
 967         __u32 startsect;
 968         __u32 start_cluster;
 969         boot_sector bs;
 970         volume_info volinfo;
 971         fsdata datablock;
 972         fsdata *mydata = &datablock;
 973         int cursect;
 974         int ret = -1, name_len;
 975         char l_filename[VFAT_MAXLEN_BYTES];
 976
 977         *actwrite = size;
 978         dir_curclust = 0;
 979
 980         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 981                 debug("error: reading boot sector\n");
 982                 return -1;
 983         }
 984
 985         total_sector = bs.total_sect;
 986         if (total_sector == 0)
 987                 total_sector = (int)cur_part_info.size; /* cast of lbaint_t */
 988
 989         if (mydata->fatsize == 32)
 990                 mydata->fatlength = bs.fat32_length;
 991         else
 992                 mydata->fatlength = bs.fat_length;
 993
 994         mydata->fat_sect = bs.reserved;
 995
 996         cursect = mydata->rootdir_sect
 997                 = mydata->fat_sect + mydata->fatlength * bs.fats;
 998         num_of_fats = bs.fats;
 999
1000         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
1001         mydata->clust_size = bs.cluster_size;
1002
1003         if (mydata->fatsize == 32) {
1004                 mydata->data_begin = mydata->rootdir_sect -
1005                                         (mydata->clust_size * 2);
1006         } else {
1007                 int rootdir_size;
1008
1009                 rootdir_size = ((bs.dir_entries[1]  * (int)256 +
1010                                  bs.dir_entries[0]) *
1011                                  sizeof(dir_entry)) /
1012                                  mydata->sect_size;
1013                 mydata->data_begin = mydata->rootdir_sect +
1014                                         rootdir_size -
1015                                         (mydata->clust_size * 2);
1016         }
1017
1018         mydata->fatbufnum = -1;
1019         mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
1020         if (mydata->fatbuf == NULL) {
1021                 debug("Error: allocating memory\n");
1022                 return -1;
1023         }
1024
1025         if (disk_read(cursect,
1026                 (mydata->fatsize == 32) ?
1027                 (mydata->clust_size) :
1028                 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
1029                 debug("Error: reading rootdir block\n");
1030                 goto exit;
1031         }
1032         dentptr = (dir_entry *) do_fat_read_at_block;
1033
1034         name_len = strlen(filename);
1035         if (name_len >= VFAT_MAXLEN_BYTES)
1036                 name_len = VFAT_MAXLEN_BYTES - 1;
1037
1038         memcpy(l_filename, filename, name_len);
1039         l_filename[name_len] = 0; /* terminate the string */
1040         downcase(l_filename);
1041
1042         startsect = mydata->rootdir_sect;
1043         retdent = find_directory_entry(mydata, startsect,
1044                                 l_filename, dentptr, 0);
1045         if (retdent) {
1046                 /* Update file size and start_cluster in a directory entry */
1047                 retdent->size = cpu_to_le32(size);
1048                 start_cluster = START(retdent);
1049
1050                 if (start_cluster) {
1051                         if (size) {
1052                                 ret = check_overflow(mydata, start_cluster,
1053                                                         size);
1054                                 if (ret) {
1055                                         printf("Error: %llu overflow\n", size);
1056                                         goto exit;
1057                                 }
1058                         }
1059
1060                         ret = clear_fatent(mydata, start_cluster);
1061                         if (ret) {
1062                                 printf("Error: clearing FAT entries\n");
1063                                 goto exit;
1064                         }
1065
1066                         if (!size)
1067                                 set_start_cluster(mydata, retdent, 0);
1068                 } else if (size) {
1069                         ret = start_cluster = find_empty_cluster(mydata);
1070                         if (ret < 0) {
1071                                 printf("Error: finding empty cluster\n");
1072                                 goto exit;
1073                         }
1074
1075                         ret = check_overflow(mydata, start_cluster, size);
1076                         if (ret) {
1077                                 printf("Error: %llu overflow\n", size);
1078                                 goto exit;
1079                         }
1080
1081                         set_start_cluster(mydata, retdent, start_cluster);
1082                 }
1083         } else {
1084                 /* Set short name to set alias checksum field in dir_slot */
1085                 set_name(empty_dentptr, filename);
1086                 fill_dir_slot(mydata, &empty_dentptr, filename);
1087
1088                 if (size) {
1089                         ret = start_cluster = find_empty_cluster(mydata);
1090                         if (ret < 0) {
1091                                 printf("Error: finding empty cluster\n");
1092                                 goto exit;
1093                         }
1094
1095                         ret = check_overflow(mydata, start_cluster, size);
1096                         if (ret) {
1097                                 printf("Error: %llu overflow\n", size);
1098                                 goto exit;
1099                         }
1100                 } else {
1101                         start_cluster = 0;
1102                 }
1103
1104                 /* Set attribute as archieve for regular file */
1105                 fill_dentry(mydata, empty_dentptr, filename,
1106                         start_cluster, size, 0x20);
1107
1108                 retdent = empty_dentptr;
1109         }
1110
1111         ret = set_contents(mydata, retdent, buffer, size, actwrite);
1112         if (ret < 0) {
1113                 printf("Error: writing contents\n");
1114                 goto exit;
1115         }
1116         debug("attempt to write 0x%llx bytes\n", *actwrite);
1117
1118         /* Flush fat buffer */
1119         ret = flush_fat_buffer(mydata);
1120         if (ret) {
1121                 printf("Error: flush fat buffer\n");
1122                 goto exit;
1123         }
1124
1125         /* Write directory table to device */
1126         ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
1127                         mydata->clust_size * mydata->sect_size);
1128         if (ret)
1129                 printf("Error: writing directory entry\n");
1130
1131 exit:
1132         free(mydata->fatbuf);
1133         return ret;
1134 }
1135
1136 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1137                    loff_t maxsize, loff_t *actwrite)
1138 {
1139         if (offset != 0) {
1140                 printf("Error: non zero offset is currently not suported.\n");
1141                 return -1;
1142         }
1143
1144         printf("writing %s\n", filename);
1145         return do_fat_write(filename, buffer, maxsize, actwrite);
1146 }