fs/fat/fat_write.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * fat_write.c
   4  *
   5  * R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
   6  */
   7
   8 #include <common.h>
   9 #include <command.h>
  10 #include <config.h>
  11 #include <fat.h>
  12 #include <malloc.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 /*
 104  * Write fat buffer into block device
 105  */
 106 static int flush_dirty_fat_buffer(fsdata *mydata)
 107 {
 108         int getsize = FATBUFBLOCKS;
 109         __u32 fatlength = mydata->fatlength;
 110         __u8 *bufptr = mydata->fatbuf;
 111         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 112
 113         debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum,
 114               (int)mydata->fat_dirty);
 115
 116         if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1))
 117                 return 0;
 118
 119         /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 120         if (startblock + getsize > fatlength)
 121                 getsize = fatlength - startblock;
 122
 123         startblock += mydata->fat_sect;
 124
 125         /* Write FAT buf */
 126         if (disk_write(startblock, getsize, bufptr) < 0) {
 127                 debug("error: writing FAT blocks\n");
 128                 return -1;
 129         }
 130
 131         if (mydata->fats == 2) {
 132                 /* Update corresponding second FAT blocks */
 133                 startblock += mydata->fatlength;
 134                 if (disk_write(startblock, getsize, bufptr) < 0) {
 135                         debug("error: writing second FAT blocks\n");
 136                         return -1;
 137                 }
 138         }
 139         mydata->fat_dirty = 0;
 140
 141         return 0;
 142 }
 143
 144 /*
 145  * Set the file name information from 'name' into 'slotptr',
 146  */
 147 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 148 {
 149         int j, end_idx = 0;
 150
 151         for (j = 0; j <= 8; j += 2) {
 152                 if (name[*idx] == 0x00) {
 153                         slotptr->name0_4[j] = 0;
 154                         slotptr->name0_4[j + 1] = 0;
 155                         end_idx++;
 156                         goto name0_4;
 157                 }
 158                 slotptr->name0_4[j] = name[*idx];
 159                 (*idx)++;
 160                 end_idx++;
 161         }
 162         for (j = 0; j <= 10; j += 2) {
 163                 if (name[*idx] == 0x00) {
 164                         slotptr->name5_10[j] = 0;
 165                         slotptr->name5_10[j + 1] = 0;
 166                         end_idx++;
 167                         goto name5_10;
 168                 }
 169                 slotptr->name5_10[j] = name[*idx];
 170                 (*idx)++;
 171                 end_idx++;
 172         }
 173         for (j = 0; j <= 2; j += 2) {
 174                 if (name[*idx] == 0x00) {
 175                         slotptr->name11_12[j] = 0;
 176                         slotptr->name11_12[j + 1] = 0;
 177                         end_idx++;
 178                         goto name11_12;
 179                 }
 180                 slotptr->name11_12[j] = name[*idx];
 181                 (*idx)++;
 182                 end_idx++;
 183         }
 184
 185         if (name[*idx] == 0x00)
 186                 return 1;
 187
 188         return 0;
 189 /* Not used characters are filled with 0xff 0xff */
 190 name0_4:
 191         for (; end_idx < 5; end_idx++) {
 192                 slotptr->name0_4[end_idx * 2] = 0xff;
 193                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 194         }
 195         end_idx = 5;
 196 name5_10:
 197         end_idx -= 5;
 198         for (; end_idx < 6; end_idx++) {
 199                 slotptr->name5_10[end_idx * 2] = 0xff;
 200                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 201         }
 202         end_idx = 11;
 203 name11_12:
 204         end_idx -= 11;
 205         for (; end_idx < 2; end_idx++) {
 206                 slotptr->name11_12[end_idx * 2] = 0xff;
 207                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 208         }
 209
 210         return 1;
 211 }
 212
 213 static int new_dir_table(fat_itr *itr);
 214 static int flush_dir(fat_itr *itr);
 215
 216 /*
 217  * Fill dir_slot entries with appropriate name, id, and attr
 218  * 'itr' will point to a next entry
 219  */
 220 static int
 221 fill_dir_slot(fat_itr *itr, const char *l_name)
 222 {
 223         __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
 224         dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
 225         __u8 counter = 0, checksum;
 226         int idx = 0, ret;
 227
 228         /* Get short file name checksum value */
 229         checksum = mkcksum(itr->dent->name, itr->dent->ext);
 230
 231         do {
 232                 memset(slotptr, 0x00, sizeof(dir_slot));
 233                 ret = str2slot(slotptr, l_name, &idx);
 234                 slotptr->id = ++counter;
 235                 slotptr->attr = ATTR_VFAT;
 236                 slotptr->alias_checksum = checksum;
 237                 slotptr++;
 238         } while (ret == 0);
 239
 240         slotptr--;
 241         slotptr->id |= LAST_LONG_ENTRY_MASK;
 242
 243         while (counter >= 1) {
 244                 memcpy(itr->dent, slotptr, sizeof(dir_slot));
 245                 slotptr--;
 246                 counter--;
 247
 248                 if (itr->remaining == 0)
 249                         flush_dir(itr);
 250
 251                 /* allocate a cluster for more entries */
 252                 if (!fat_itr_next(itr))
 253                         if (!itr->dent &&
 254                             (!itr->is_root || itr->fsdata->fatsize == 32) &&
 255                             new_dir_table(itr))
 256                                 return -1;
 257         }
 258
 259         return 0;
 260 }
 261
 262 /*
 263  * Set the entry at index 'entry' in a FAT (12/16/32) table.
 264  */
 265 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 266 {
 267         __u32 bufnum, offset, off16;
 268         __u16 val1, val2;
 269
 270         switch (mydata->fatsize) {
 271         case 32:
 272                 bufnum = entry / FAT32BUFSIZE;
 273                 offset = entry - bufnum * FAT32BUFSIZE;
 274                 break;
 275         case 16:
 276                 bufnum = entry / FAT16BUFSIZE;
 277                 offset = entry - bufnum * FAT16BUFSIZE;
 278                 break;
 279         case 12:
 280                 bufnum = entry / FAT12BUFSIZE;
 281                 offset = entry - bufnum * FAT12BUFSIZE;
 282                 break;
 283         default:
 284                 /* Unsupported FAT size */
 285                 return -1;
 286         }
 287
 288         /* Read a new block of FAT entries into the cache. */
 289         if (bufnum != mydata->fatbufnum) {
 290                 int getsize = FATBUFBLOCKS;
 291                 __u8 *bufptr = mydata->fatbuf;
 292                 __u32 fatlength = mydata->fatlength;
 293                 __u32 startblock = bufnum * FATBUFBLOCKS;
 294
 295                 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 296                 if (startblock + getsize > fatlength)
 297                         getsize = fatlength - startblock;
 298
 299                 if (flush_dirty_fat_buffer(mydata) < 0)
 300                         return -1;
 301
 302                 startblock += mydata->fat_sect;
 303
 304                 if (disk_read(startblock, getsize, bufptr) < 0) {
 305                         debug("Error reading FAT blocks\n");
 306                         return -1;
 307                 }
 308                 mydata->fatbufnum = bufnum;
 309         }
 310
 311         /* Mark as dirty */
 312         mydata->fat_dirty = 1;
 313
 314         /* Set the actual entry */
 315         switch (mydata->fatsize) {
 316         case 32:
 317                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 318                 break;
 319         case 16:
 320                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 321                 break;
 322         case 12:
 323                 off16 = (offset * 3) / 4;
 324
 325                 switch (offset & 0x3) {
 326                 case 0:
 327                         val1 = cpu_to_le16(entry_value) & 0xfff;
 328                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
 329                         ((__u16 *)mydata->fatbuf)[off16] |= val1;
 330                         break;
 331                 case 1:
 332                         val1 = cpu_to_le16(entry_value) & 0xf;
 333                         val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
 334
 335                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
 336                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
 337
 338                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
 339                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 340                         break;
 341                 case 2:
 342                         val1 = cpu_to_le16(entry_value) & 0xff;
 343                         val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
 344
 345                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
 346                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
 347
 348                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
 349                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 350                         break;
 351                 case 3:
 352                         val1 = cpu_to_le16(entry_value) & 0xfff;
 353                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
 354                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
 355                         break;
 356                 default:
 357                         break;
 358                 }
 359
 360                 break;
 361         default:
 362                 return -1;
 363         }
 364
 365         return 0;
 366 }
 367
 368 /*
 369  * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
 370  * and link it to 'entry'. EOC marker is not set on returned entry.
 371  */
 372 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 373 {
 374         __u32 next_fat, next_entry = entry + 1;
 375
 376         while (1) {
 377                 next_fat = get_fatent(mydata, next_entry);
 378                 if (next_fat == 0) {
 379                         /* found free entry, link to entry */
 380                         set_fatent_value(mydata, entry, next_entry);
 381                         break;
 382                 }
 383                 next_entry++;
 384         }
 385         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 386                mydata->fatsize, entry, next_entry);
 387
 388         return next_entry;
 389 }
 390
 391 /**
 392  * set_sectors() - write data to sectors
 393  *
 394  * Write 'size' bytes from 'buffer' into the specified sector.
 395  *
 396  * @mydata:     data to be written
 397  * @startsect:  sector to be written to
 398  * @buffer:     data to be written
 399  * @size:       bytes to be written (but not more than the size of a cluster)
 400  * Return:      0 on success, -1 otherwise
 401  */
 402 static int
 403 set_sectors(fsdata *mydata, u32 startsect, u8 *buffer, u32 size)
 404 {
 405         u32 nsects = 0;
 406         int ret;
 407
 408         debug("startsect: %d\n", startsect);
 409
 410         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 411                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 412
 413                 debug("FAT: Misaligned buffer address (%p)\n", buffer);
 414
 415                 while (size >= mydata->sect_size) {
 416                         memcpy(tmpbuf, buffer, mydata->sect_size);
 417                         ret = disk_write(startsect++, 1, tmpbuf);
 418                         if (ret != 1) {
 419                                 debug("Error writing data (got %d)\n", ret);
 420                                 return -1;
 421                         }
 422
 423                         buffer += mydata->sect_size;
 424                         size -= mydata->sect_size;
 425                 }
 426         } else if (size >= mydata->sect_size) {
 427                 nsects = size / mydata->sect_size;
 428                 ret = disk_write(startsect, nsects, buffer);
 429                 if (ret != nsects) {
 430                         debug("Error writing data (got %d)\n", ret);
 431                         return -1;
 432                 }
 433
 434                 startsect += nsects;
 435                 buffer += nsects * mydata->sect_size;
 436                 size -= nsects * mydata->sect_size;
 437         }
 438
 439         if (size) {
 440                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 441                 /* Do not leak content of stack */
 442                 memset(tmpbuf, 0, mydata->sect_size);
 443                 memcpy(tmpbuf, buffer, size);
 444                 ret = disk_write(startsect, 1, tmpbuf);
 445                 if (ret != 1) {
 446                         debug("Error writing data (got %d)\n", ret);
 447                         return -1;
 448                 }
 449         }
 450
 451         return 0;
 452 }
 453
 454 /**
 455  * set_cluster() - write data to cluster
 456  *
 457  * Write 'size' bytes from 'buffer' into the specified cluster.
 458  *
 459  * @mydata:     data to be written
 460  * @clustnum:   cluster to be written to
 461  * @buffer:     data to be written
 462  * @size:       bytes to be written (but not more than the size of a cluster)
 463  * Return:      0 on success, -1 otherwise
 464  */
 465 static int
 466 set_cluster(fsdata *mydata, u32 clustnum, u8 *buffer, u32 size)
 467 {
 468         return set_sectors(mydata, clust_to_sect(mydata, clustnum),
 469                            buffer, size);
 470 }
 471
 472 static int
 473 flush_dir(fat_itr *itr)
 474 {
 475         fsdata *mydata = itr->fsdata;
 476         u32 startsect, sect_offset, nsects;
 477
 478         if (!itr->is_root || mydata->fatsize == 32)
 479                 return set_cluster(mydata, itr->clust, itr->block,
 480                                    mydata->clust_size * mydata->sect_size);
 481
 482         sect_offset = itr->clust * mydata->clust_size;
 483         startsect = mydata->rootdir_sect + sect_offset;
 484         /* do not write past the end of rootdir */
 485         nsects = min_t(u32, mydata->clust_size,
 486                        mydata->rootdir_size - sect_offset);
 487
 488         return set_sectors(mydata, startsect, itr->block,
 489                            nsects * mydata->sect_size);
 490 }
 491
 492 static __u8 tmpbuf_cluster[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
 493
 494 /*
 495  * Read and modify data on existing and consecutive cluster blocks
 496  */
 497 static int
 498 get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
 499                 loff_t size, loff_t *gotsize)
 500 {
 501         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 502         __u32 startsect;
 503         loff_t wsize;
 504         int clustcount, i, ret;
 505
 506         *gotsize = 0;
 507         if (!size)
 508                 return 0;
 509
 510         assert(pos < bytesperclust);
 511         startsect = clust_to_sect(mydata, clustnum);
 512
 513         debug("clustnum: %d, startsect: %d, pos: %lld\n",
 514               clustnum, startsect, pos);
 515
 516         /* partial write at beginning */
 517         if (pos) {
 518                 wsize = min(bytesperclust - pos, size);
 519                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 520                 if (ret != mydata->clust_size) {
 521                         debug("Error reading data (got %d)\n", ret);
 522                         return -1;
 523                 }
 524
 525                 memcpy(tmpbuf_cluster + pos, buffer, wsize);
 526                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 527                 if (ret != mydata->clust_size) {
 528                         debug("Error writing data (got %d)\n", ret);
 529                         return -1;
 530                 }
 531
 532                 size -= wsize;
 533                 buffer += wsize;
 534                 *gotsize += wsize;
 535
 536                 startsect += mydata->clust_size;
 537
 538                 if (!size)
 539                         return 0;
 540         }
 541
 542         /* full-cluster write */
 543         if (size >= bytesperclust) {
 544                 clustcount = lldiv(size, bytesperclust);
 545
 546                 if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
 547                         wsize = clustcount * bytesperclust;
 548                         ret = disk_write(startsect,
 549                                          clustcount * mydata->clust_size,
 550                                          buffer);
 551                         if (ret != clustcount * mydata->clust_size) {
 552                                 debug("Error writing data (got %d)\n", ret);
 553                                 return -1;
 554                         }
 555
 556                         size -= wsize;
 557                         buffer += wsize;
 558                         *gotsize += wsize;
 559
 560                         startsect += clustcount * mydata->clust_size;
 561                 } else {
 562                         for (i = 0; i < clustcount; i++) {
 563                                 memcpy(tmpbuf_cluster, buffer, bytesperclust);
 564                                 ret = disk_write(startsect,
 565                                                  mydata->clust_size,
 566                                                  tmpbuf_cluster);
 567                                 if (ret != mydata->clust_size) {
 568                                         debug("Error writing data (got %d)\n",
 569                                               ret);
 570                                         return -1;
 571                                 }
 572
 573                                 size -= bytesperclust;
 574                                 buffer += bytesperclust;
 575                                 *gotsize += bytesperclust;
 576
 577                                 startsect += mydata->clust_size;
 578                         }
 579                 }
 580         }
 581
 582         /* partial write at end */
 583         if (size) {
 584                 wsize = size;
 585                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 586                 if (ret != mydata->clust_size) {
 587                         debug("Error reading data (got %d)\n", ret);
 588                         return -1;
 589                 }
 590                 memcpy(tmpbuf_cluster, buffer, wsize);
 591                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 592                 if (ret != mydata->clust_size) {
 593                         debug("Error writing data (got %d)\n", ret);
 594                         return -1;
 595                 }
 596
 597                 size -= wsize;
 598                 buffer += wsize;
 599                 *gotsize += wsize;
 600         }
 601
 602         assert(!size);
 603
 604         return 0;
 605 }
 606
 607 /*
 608  * Find the first empty cluster
 609  */
 610 static int find_empty_cluster(fsdata *mydata)
 611 {
 612         __u32 fat_val, entry = 3;
 613
 614         while (1) {
 615                 fat_val = get_fatent(mydata, entry);
 616                 if (fat_val == 0)
 617                         break;
 618                 entry++;
 619         }
 620
 621         return entry;
 622 }
 623
 624 /*
 625  * Allocate a cluster for additional directory entries
 626  */
 627 static int new_dir_table(fat_itr *itr)
 628 {
 629         fsdata *mydata = itr->fsdata;
 630         int dir_newclust = 0;
 631         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 632
 633         dir_newclust = find_empty_cluster(mydata);
 634         set_fatent_value(mydata, itr->clust, dir_newclust);
 635         if (mydata->fatsize == 32)
 636                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 637         else if (mydata->fatsize == 16)
 638                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 639         else if (mydata->fatsize == 12)
 640                 set_fatent_value(mydata, dir_newclust, 0xff8);
 641
 642         itr->clust = dir_newclust;
 643         itr->next_clust = dir_newclust;
 644
 645         if (flush_dirty_fat_buffer(mydata) < 0)
 646                 return -1;
 647
 648         memset(itr->block, 0x00, bytesperclust);
 649
 650         itr->dent = (dir_entry *)itr->block;
 651         itr->last_cluster = 1;
 652         itr->remaining = bytesperclust / sizeof(dir_entry) - 1;
 653
 654         return 0;
 655 }
 656
 657 /*
 658  * Set empty cluster from 'entry' to the end of a file
 659  */
 660 static int clear_fatent(fsdata *mydata, __u32 entry)
 661 {
 662         __u32 fat_val;
 663
 664         while (!CHECK_CLUST(entry, mydata->fatsize)) {
 665                 fat_val = get_fatent(mydata, entry);
 666                 if (fat_val != 0)
 667                         set_fatent_value(mydata, entry, 0);
 668                 else
 669                         break;
 670
 671                 entry = fat_val;
 672         }
 673
 674         /* Flush fat buffer */
 675         if (flush_dirty_fat_buffer(mydata) < 0)
 676                 return -1;
 677
 678         return 0;
 679 }
 680
 681 /*
 682  * Set start cluster in directory entry
 683  */
 684 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 685                               __u32 start_cluster)
 686 {
 687         if (mydata->fatsize == 32)
 688                 dentptr->starthi =
 689                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 690         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 691 }
 692
 693 /*
 694  * Check whether adding a file makes the file system to
 695  * exceed the size of the block device
 696  * Return -1 when overflow occurs, otherwise return 0
 697  */
 698 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 699 {
 700         __u32 startsect, sect_num, offset;
 701
 702         if (clustnum > 0)
 703                 startsect = clust_to_sect(mydata, clustnum);
 704         else
 705                 startsect = mydata->rootdir_sect;
 706
 707         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 708
 709         if (offset != 0)
 710                 sect_num++;
 711
 712         if (startsect + sect_num > total_sector)
 713                 return -1;
 714         return 0;
 715 }
 716
 717 /*
 718  * Write at most 'maxsize' bytes from 'buffer' into
 719  * the file associated with 'dentptr'
 720  * Update the number of bytes written in *gotsize and return 0
 721  * or return -1 on fatal errors.
 722  */
 723 static int
 724 set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
 725              loff_t maxsize, loff_t *gotsize)
 726 {
 727         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 728         __u32 curclust = START(dentptr);
 729         __u32 endclust = 0, newclust = 0;
 730         u64 cur_pos, filesize;
 731         loff_t offset, actsize, wsize;
 732
 733         *gotsize = 0;
 734         filesize = pos + maxsize;
 735
 736         debug("%llu bytes\n", filesize);
 737
 738         if (!filesize) {
 739                 if (!curclust)
 740                         return 0;
 741                 if (!CHECK_CLUST(curclust, mydata->fatsize) ||
 742                     IS_LAST_CLUST(curclust, mydata->fatsize)) {
 743                         clear_fatent(mydata, curclust);
 744                         set_start_cluster(mydata, dentptr, 0);
 745                         return 0;
 746                 }
 747                 debug("curclust: 0x%x\n", curclust);
 748                 debug("Invalid FAT entry\n");
 749                 return -1;
 750         }
 751
 752         if (!curclust) {
 753                 assert(pos == 0);
 754                 goto set_clusters;
 755         }
 756
 757         /* go to cluster at pos */
 758         cur_pos = bytesperclust;
 759         while (1) {
 760                 if (pos <= cur_pos)
 761                         break;
 762                 if (IS_LAST_CLUST(curclust, mydata->fatsize))
 763                         break;
 764
 765                 newclust = get_fatent(mydata, curclust);
 766                 if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
 767                     CHECK_CLUST(newclust, mydata->fatsize)) {
 768                         debug("curclust: 0x%x\n", curclust);
 769                         debug("Invalid FAT entry\n");
 770                         return -1;
 771                 }
 772
 773                 cur_pos += bytesperclust;
 774                 curclust = newclust;
 775         }
 776         if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 777                 assert(pos == cur_pos);
 778                 goto set_clusters;
 779         }
 780
 781         assert(pos < cur_pos);
 782         cur_pos -= bytesperclust;
 783
 784         /* overwrite */
 785         assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
 786                !CHECK_CLUST(curclust, mydata->fatsize));
 787
 788         while (1) {
 789                 /* search for allocated consecutive clusters */
 790                 actsize = bytesperclust;
 791                 endclust = curclust;
 792                 while (1) {
 793                         if (filesize <= (cur_pos + actsize))
 794                                 break;
 795
 796                         newclust = get_fatent(mydata, endclust);
 797
 798                         if (IS_LAST_CLUST(newclust, mydata->fatsize))
 799                                 break;
 800                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 801                                 debug("curclust: 0x%x\n", curclust);
 802                                 debug("Invalid FAT entry\n");
 803                                 return -1;
 804                         }
 805
 806                         actsize += bytesperclust;
 807                         endclust = newclust;
 808                 }
 809
 810                 /* overwrite to <curclust..endclust> */
 811                 if (pos < cur_pos)
 812                         offset = 0;
 813                 else
 814                         offset = pos - cur_pos;
 815                 wsize = min(cur_pos + actsize, filesize) - pos;
 816                 if (get_set_cluster(mydata, curclust, offset,
 817                                     buffer, wsize, &actsize)) {
 818                         printf("Error get-and-setting cluster\n");
 819                         return -1;
 820                 }
 821                 buffer += wsize;
 822                 *gotsize += wsize;
 823                 cur_pos += offset + wsize;
 824
 825                 if (filesize <= cur_pos)
 826                         break;
 827
 828                 /* CHECK: newclust = get_fatent(mydata, endclust); */
 829
 830                 if (IS_LAST_CLUST(newclust, mydata->fatsize))
 831                         /* no more clusters */
 832                         break;
 833
 834                 curclust = newclust;
 835         }
 836
 837         if (filesize <= cur_pos) {
 838                 /* no more write */
 839                 newclust = get_fatent(mydata, endclust);
 840                 if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
 841                         /* truncate the rest */
 842                         clear_fatent(mydata, newclust);
 843
 844                         /* Mark end of file in FAT */
 845                         if (mydata->fatsize == 12)
 846                                 newclust = 0xfff;
 847                         else if (mydata->fatsize == 16)
 848                                 newclust = 0xffff;
 849                         else if (mydata->fatsize == 32)
 850                                 newclust = 0xfffffff;
 851                         set_fatent_value(mydata, endclust, newclust);
 852                 }
 853
 854                 return 0;
 855         }
 856
 857         curclust = endclust;
 858         filesize -= cur_pos;
 859         assert(!do_div(cur_pos, bytesperclust));
 860
 861 set_clusters:
 862         /* allocate and write */
 863         assert(!pos);
 864
 865         /* Assure that curclust is valid */
 866         if (!curclust) {
 867                 curclust = find_empty_cluster(mydata);
 868                 set_start_cluster(mydata, dentptr, curclust);
 869         } else {
 870                 newclust = get_fatent(mydata, curclust);
 871
 872                 if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
 873                         newclust = determine_fatent(mydata, curclust);
 874                         set_fatent_value(mydata, curclust, newclust);
 875                         curclust = newclust;
 876                 } else {
 877                         debug("error: something wrong\n");
 878                         return -1;
 879                 }
 880         }
 881
 882         /* TODO: already partially written */
 883         if (check_overflow(mydata, curclust, filesize)) {
 884                 printf("Error: no space left: %llu\n", filesize);
 885                 return -1;
 886         }
 887
 888         actsize = bytesperclust;
 889         endclust = curclust;
 890         do {
 891                 /* search for consecutive clusters */
 892                 while (actsize < filesize) {
 893                         newclust = determine_fatent(mydata, endclust);
 894
 895                         if ((newclust - 1) != endclust)
 896                                 /* write to <curclust..endclust> */
 897                                 goto getit;
 898
 899                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 900                                 debug("newclust: 0x%x\n", newclust);
 901                                 debug("Invalid FAT entry\n");
 902                                 return 0;
 903                         }
 904                         endclust = newclust;
 905                         actsize += bytesperclust;
 906                 }
 907
 908                 /* set remaining bytes */
 909                 actsize = filesize;
 910                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 911                         debug("error: writing cluster\n");
 912                         return -1;
 913                 }
 914                 *gotsize += actsize;
 915
 916                 /* Mark end of file in FAT */
 917                 if (mydata->fatsize == 12)
 918                         newclust = 0xfff;
 919                 else if (mydata->fatsize == 16)
 920                         newclust = 0xffff;
 921                 else if (mydata->fatsize == 32)
 922                         newclust = 0xfffffff;
 923                 set_fatent_value(mydata, endclust, newclust);
 924
 925                 return 0;
 926 getit:
 927                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 928                         debug("error: writing cluster\n");
 929                         return -1;
 930                 }
 931                 *gotsize += actsize;
 932                 filesize -= actsize;
 933                 buffer += actsize;
 934
 935                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 936                         debug("newclust: 0x%x\n", newclust);
 937                         debug("Invalid FAT entry\n");
 938                         return 0;
 939                 }
 940                 actsize = bytesperclust;
 941                 curclust = endclust = newclust;
 942         } while (1);
 943
 944         return 0;
 945 }
 946
 947 /*
 948  * Fill dir_entry
 949  */
 950 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 951         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 952 {
 953         set_start_cluster(mydata, dentptr, start_cluster);
 954         dentptr->size = cpu_to_le32(size);
 955
 956         dentptr->attr = attr;
 957
 958         set_name(dentptr, filename);
 959 }
 960
 961 /*
 962  * Find a directory entry based on filename or start cluster number
 963  * If the directory entry is not found,
 964  * the new position for writing a directory entry will be returned
 965  */
 966 static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
 967 {
 968         int match = 0;
 969
 970         while (fat_itr_next(itr)) {
 971                 /* check both long and short name: */
 972                 if (!strcasecmp(filename, itr->name))
 973                         match = 1;
 974                 else if (itr->name != itr->s_name &&
 975                          !strcasecmp(filename, itr->s_name))
 976                         match = 1;
 977
 978                 if (!match)
 979                         continue;
 980
 981                 if (itr->dent->name[0] == '\0')
 982                         return NULL;
 983                 else
 984                         return itr->dent;
 985         }
 986
 987         /* allocate a cluster for more entries */
 988         if (!itr->dent &&
 989             (!itr->is_root || itr->fsdata->fatsize == 32) &&
 990             new_dir_table(itr))
 991                 /* indicate that allocating dent failed */
 992                 itr->dent = NULL;
 993
 994         return NULL;
 995 }
 996
 997 static int split_filename(char *filename, char **dirname, char **basename)
 998 {
 999         char *p, *last_slash, *last_slash_cont;
1000
1001 again:
1002         p = filename;
1003         last_slash = NULL;
1004         last_slash_cont = NULL;
1005         while (*p) {
1006                 if (ISDIRDELIM(*p)) {
1007                         last_slash = p;
1008                         last_slash_cont = p;
1009                         /* continuous slashes */
1010                         while (ISDIRDELIM(*p))
1011                                 last_slash_cont = p++;
1012                         if (!*p)
1013                                 break;
1014                 }
1015                 p++;
1016         }
1017
1018         if (last_slash) {
1019                 if (last_slash_cont == (filename + strlen(filename) - 1)) {
1020                         /* remove trailing slashes */
1021                         *last_slash = '\0';
1022                         goto again;
1023                 }
1024
1025                 if (last_slash == filename) {
1026                         /* avoid ""(null) directory */
1027                         *dirname = "/";
1028                 } else {
1029                         *last_slash = '\0';
1030                         *dirname = filename;
1031                 }
1032
1033                 *last_slash_cont = '\0';
1034                 *basename = last_slash_cont + 1;
1035         } else {
1036                 *dirname = "/"; /* root by default */
1037                 *basename = filename;
1038         }
1039
1040         return 0;
1041 }
1042
1043 /**
1044  * normalize_longname() - check long file name and convert to lower case
1045  *
1046  * We assume here that the FAT file system is using an 8bit code page.
1047  * Linux typically uses CP437, EDK2 assumes CP1250.
1048  *
1049  * @l_filename: preallocated buffer receiving the normalized name
1050  * @filename:   filename to normalize
1051  * Return:      0 on success, -1 on failure
1052  */
1053 static int normalize_longname(char *l_filename, const char *filename)
1054 {
1055         const char *p, illegal[] = "<>:\"/\\|?*";
1056
1057         if (strlen(filename) >= VFAT_MAXLEN_BYTES)
1058                 return -1;
1059
1060         for (p = filename; *p; ++p) {
1061                 if ((unsigned char)*p < 0x20)
1062                         return -1;
1063                 if (strchr(illegal, *p))
1064                         return -1;
1065         }
1066
1067         strcpy(l_filename, filename);
1068         downcase(l_filename, VFAT_MAXLEN_BYTES);
1069
1070         return 0;
1071 }
1072
1073 int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
1074                       loff_t size, loff_t *actwrite)
1075 {
1076         dir_entry *retdent;
1077         fsdata datablock = { .fatbuf = NULL, };
1078         fsdata *mydata = &datablock;
1079         fat_itr *itr = NULL;
1080         int ret = -1;
1081         char *filename_copy, *parent, *basename;
1082         char l_filename[VFAT_MAXLEN_BYTES];
1083
1084         debug("writing %s\n", filename);
1085
1086         filename_copy = strdup(filename);
1087         if (!filename_copy)
1088                 return -ENOMEM;
1089
1090         split_filename(filename_copy, &parent, &basename);
1091         if (!strlen(basename)) {
1092                 ret = -EINVAL;
1093                 goto exit;
1094         }
1095
1096         filename = basename;
1097         if (normalize_longname(l_filename, filename)) {
1098                 printf("FAT: illegal filename (%s)\n", filename);
1099                 ret = -EINVAL;
1100                 goto exit;
1101         }
1102
1103         itr = malloc_cache_aligned(sizeof(fat_itr));
1104         if (!itr) {
1105                 ret = -ENOMEM;
1106                 goto exit;
1107         }
1108
1109         ret = fat_itr_root(itr, &datablock);
1110         if (ret)
1111                 goto exit;
1112
1113         total_sector = datablock.total_sect;
1114
1115         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1116         if (ret) {
1117                 printf("%s: doesn't exist (%d)\n", parent, ret);
1118                 goto exit;
1119         }
1120
1121         retdent = find_directory_entry(itr, l_filename);
1122
1123         if (retdent) {
1124                 if (fat_itr_isdir(itr)) {
1125                         ret = -EISDIR;
1126                         goto exit;
1127                 }
1128
1129                 /* A file exists */
1130                 if (pos == -1)
1131                         /* Append to the end */
1132                         pos = FAT2CPU32(retdent->size);
1133                 if (pos > retdent->size) {
1134                         /* No hole allowed */
1135                         ret = -EINVAL;
1136                         goto exit;
1137                 }
1138
1139                 /* Update file size in a directory entry */
1140                 retdent->size = cpu_to_le32(pos + size);
1141         } else {
1142                 /* Create a new file */
1143
1144                 if (itr->is_root) {
1145                         /* root dir cannot have "." or ".." */
1146                         if (!strcmp(l_filename, ".") ||
1147                             !strcmp(l_filename, "..")) {
1148                                 ret = -EINVAL;
1149                                 goto exit;
1150                         }
1151                 }
1152
1153                 if (!itr->dent) {
1154                         printf("Error: allocating new dir entry\n");
1155                         ret = -EIO;
1156                         goto exit;
1157                 }
1158
1159                 if (pos) {
1160                         /* No hole allowed */
1161                         ret = -EINVAL;
1162                         goto exit;
1163                 }
1164
1165                 memset(itr->dent, 0, sizeof(*itr->dent));
1166
1167                 /* Calculate checksum for short name */
1168                 set_name(itr->dent, filename);
1169
1170                 /* Set long name entries */
1171                 if (fill_dir_slot(itr, filename)) {
1172                         ret = -EIO;
1173                         goto exit;
1174                 }
1175
1176                 /* Set short name entry */
1177                 fill_dentry(itr->fsdata, itr->dent, filename, 0, size, 0x20);
1178
1179                 retdent = itr->dent;
1180         }
1181
1182         ret = set_contents(mydata, retdent, pos, buffer, size, actwrite);
1183         if (ret < 0) {
1184                 printf("Error: writing contents\n");
1185                 ret = -EIO;
1186                 goto exit;
1187         }
1188         debug("attempt to write 0x%llx bytes\n", *actwrite);
1189
1190         /* Flush fat buffer */
1191         ret = flush_dirty_fat_buffer(mydata);
1192         if (ret) {
1193                 printf("Error: flush fat buffer\n");
1194                 ret = -EIO;
1195                 goto exit;
1196         }
1197
1198         /* Write directory table to device */
1199         ret = flush_dir(itr);
1200         if (ret) {
1201                 printf("Error: writing directory entry\n");
1202                 ret = -EIO;
1203         }
1204
1205 exit:
1206         free(filename_copy);
1207         free(mydata->fatbuf);
1208         free(itr);
1209         return ret;
1210 }
1211
1212 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1213                    loff_t maxsize, loff_t *actwrite)
1214 {
1215         return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
1216 }
1217
1218 static int fat_dir_entries(fat_itr *itr)
1219 {
1220         fat_itr *dirs;
1221         fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
1222                                                 /* for FATBUFSIZE */
1223         int count;
1224
1225         dirs = malloc_cache_aligned(sizeof(fat_itr));
1226         if (!dirs) {
1227                 debug("Error: allocating memory\n");
1228                 count = -ENOMEM;
1229                 goto exit;
1230         }
1231
1232         /* duplicate fsdata */
1233         fat_itr_child(dirs, itr);
1234         fsdata = *dirs->fsdata;
1235
1236         /* allocate local fat buffer */
1237         fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
1238         if (!fsdata.fatbuf) {
1239                 debug("Error: allocating memory\n");
1240                 count = -ENOMEM;
1241                 goto exit;
1242         }
1243         fsdata.fatbufnum = -1;
1244         dirs->fsdata = &fsdata;
1245
1246         for (count = 0; fat_itr_next(dirs); count++)
1247                 ;
1248
1249 exit:
1250         free(fsdata.fatbuf);
1251         free(dirs);
1252         return count;
1253 }
1254
1255 static int delete_dentry(fat_itr *itr)
1256 {
1257         fsdata *mydata = itr->fsdata;
1258         dir_entry *dentptr = itr->dent;
1259
1260         /* free cluster blocks */
1261         clear_fatent(mydata, START(dentptr));
1262         if (flush_dirty_fat_buffer(mydata) < 0) {
1263                 printf("Error: flush fat buffer\n");
1264                 return -EIO;
1265         }
1266
1267         /*
1268          * update a directory entry
1269          * TODO:
1270          *  - long file name support
1271          *  - find and mark the "new" first invalid entry as name[0]=0x00
1272          */
1273         memset(dentptr, 0, sizeof(*dentptr));
1274         dentptr->name[0] = 0xe5;
1275
1276         if (flush_dir(itr)) {
1277                 printf("error: writing directory entry\n");
1278                 return -EIO;
1279         }
1280
1281         return 0;
1282 }
1283
1284 int fat_unlink(const char *filename)
1285 {
1286         fsdata fsdata = { .fatbuf = NULL, };
1287         fat_itr *itr = NULL;
1288         int n_entries, ret;
1289         char *filename_copy, *dirname, *basename;
1290
1291         filename_copy = strdup(filename);
1292         if (!filename_copy) {
1293                 printf("Error: allocating memory\n");
1294                 ret = -ENOMEM;
1295                 goto exit;
1296         }
1297         split_filename(filename_copy, &dirname, &basename);
1298
1299         if (!strcmp(dirname, "/") && !strcmp(basename, "")) {
1300                 printf("Error: cannot remove root\n");
1301                 ret = -EINVAL;
1302                 goto exit;
1303         }
1304
1305         itr = malloc_cache_aligned(sizeof(fat_itr));
1306         if (!itr) {
1307                 printf("Error: allocating memory\n");
1308                 ret = -ENOMEM;
1309                 goto exit;
1310         }
1311
1312         ret = fat_itr_root(itr, &fsdata);
1313         if (ret)
1314                 goto exit;
1315
1316         total_sector = fsdata.total_sect;
1317
1318         ret = fat_itr_resolve(itr, dirname, TYPE_DIR);
1319         if (ret) {
1320                 printf("%s: doesn't exist (%d)\n", dirname, ret);
1321                 ret = -ENOENT;
1322                 goto exit;
1323         }
1324
1325         if (!find_directory_entry(itr, basename)) {
1326                 printf("%s: doesn't exist\n", basename);
1327                 ret = -ENOENT;
1328                 goto exit;
1329         }
1330
1331         if (fat_itr_isdir(itr)) {
1332                 n_entries = fat_dir_entries(itr);
1333                 if (n_entries < 0) {
1334                         ret = n_entries;
1335                         goto exit;
1336                 }
1337                 if (n_entries > 2) {
1338                         printf("Error: directory is not empty: %d\n",
1339                                n_entries);
1340                         ret = -EINVAL;
1341                         goto exit;
1342                 }
1343         }
1344
1345         ret = delete_dentry(itr);
1346
1347 exit:
1348         free(fsdata.fatbuf);
1349         free(itr);
1350         free(filename_copy);
1351
1352         return ret;
1353 }
1354
1355 int fat_mkdir(const char *new_dirname)
1356 {
1357         dir_entry *retdent;
1358         fsdata datablock = { .fatbuf = NULL, };
1359         fsdata *mydata = &datablock;
1360         fat_itr *itr = NULL;
1361         char *dirname_copy, *parent, *dirname;
1362         char l_dirname[VFAT_MAXLEN_BYTES];
1363         int ret = -1;
1364         loff_t actwrite;
1365         unsigned int bytesperclust;
1366         dir_entry *dotdent = NULL;
1367
1368         dirname_copy = strdup(new_dirname);
1369         if (!dirname_copy)
1370                 goto exit;
1371
1372         split_filename(dirname_copy, &parent, &dirname);
1373         if (!strlen(dirname)) {
1374                 ret = -EINVAL;
1375                 goto exit;
1376         }
1377
1378         if (normalize_longname(l_dirname, dirname)) {
1379                 printf("FAT: illegal filename (%s)\n", dirname);
1380                 ret = -EINVAL;
1381                 goto exit;
1382         }
1383
1384         itr = malloc_cache_aligned(sizeof(fat_itr));
1385         if (!itr) {
1386                 ret = -ENOMEM;
1387                 goto exit;
1388         }
1389
1390         ret = fat_itr_root(itr, &datablock);
1391         if (ret)
1392                 goto exit;
1393
1394         total_sector = datablock.total_sect;
1395
1396         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1397         if (ret) {
1398                 printf("%s: doesn't exist (%d)\n", parent, ret);
1399                 goto exit;
1400         }
1401
1402         retdent = find_directory_entry(itr, l_dirname);
1403
1404         if (retdent) {
1405                 printf("%s: already exists\n", l_dirname);
1406                 ret = -EEXIST;
1407                 goto exit;
1408         } else {
1409                 if (itr->is_root) {
1410                         /* root dir cannot have "." or ".." */
1411                         if (!strcmp(l_dirname, ".") ||
1412                             !strcmp(l_dirname, "..")) {
1413                                 ret = -EINVAL;
1414                                 goto exit;
1415                         }
1416                 }
1417
1418                 if (!itr->dent) {
1419                         printf("Error: allocating new dir entry\n");
1420                         ret = -EIO;
1421                         goto exit;
1422                 }
1423
1424                 memset(itr->dent, 0, sizeof(*itr->dent));
1425
1426                 /* Set short name to set alias checksum field in dir_slot */
1427                 set_name(itr->dent, dirname);
1428                 fill_dir_slot(itr, dirname);
1429
1430                 /* Set attribute as archive for regular file */
1431                 fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0,
1432                             ATTR_DIR | ATTR_ARCH);
1433
1434                 retdent = itr->dent;
1435         }
1436
1437         /* Default entries */
1438         bytesperclust = mydata->clust_size * mydata->sect_size;
1439         dotdent = malloc_cache_aligned(bytesperclust);
1440         if (!dotdent) {
1441                 ret = -ENOMEM;
1442                 goto exit;
1443         }
1444         memset(dotdent, 0, bytesperclust);
1445
1446         memcpy(dotdent[0].name, ".       ", 8);
1447         memcpy(dotdent[0].ext, "   ", 3);
1448         dotdent[0].attr = ATTR_DIR | ATTR_ARCH;
1449
1450         memcpy(dotdent[1].name, "..      ", 8);
1451         memcpy(dotdent[1].ext, "   ", 3);
1452         dotdent[1].attr = ATTR_DIR | ATTR_ARCH;
1453         set_start_cluster(mydata, &dotdent[1], itr->start_clust);
1454
1455         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1456                            bytesperclust, &actwrite);
1457         if (ret < 0) {
1458                 printf("Error: writing contents\n");
1459                 goto exit;
1460         }
1461         /* Write twice for "." */
1462         set_start_cluster(mydata, &dotdent[0], START(retdent));
1463         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1464                            bytesperclust, &actwrite);
1465         if (ret < 0) {
1466                 printf("Error: writing contents\n");
1467                 goto exit;
1468         }
1469
1470         /* Flush fat buffer */
1471         ret = flush_dirty_fat_buffer(mydata);
1472         if (ret) {
1473                 printf("Error: flush fat buffer\n");
1474                 goto exit;
1475         }
1476
1477         /* Write directory table to device */
1478         ret = flush_dir(itr);
1479         if (ret)
1480                 printf("Error: writing directory entry\n");
1481
1482 exit:
1483         free(dirname_copy);
1484         free(mydata->fatbuf);
1485         free(itr);
1486         free(dotdent);
1487         return ret;
1488 }