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 <asm/byteorder.h>
  13 #include <part.h>
  14 #include <linux/ctype.h>
  15 #include <div64.h>
  16 #include <linux/math64.h>
  17 #include "fat.c"
  18
  19 static void uppercase(char *str, int len)
  20 {
  21         int i;
  22
  23         for (i = 0; i < len; i++) {
  24                 *str = toupper(*str);
  25                 str++;
  26         }
  27 }
  28
  29 static int total_sector;
  30 static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
  31 {
  32         ulong ret;
  33
  34         if (!cur_dev)
  35                 return -1;
  36
  37         if (cur_part_info.start + block + nr_blocks >
  38                 cur_part_info.start + total_sector) {
  39                 printf("error: overflow occurs\n");
  40                 return -1;
  41         }
  42
  43         ret = blk_dwrite(cur_dev, cur_part_info.start + block, nr_blocks, buf);
  44         if (nr_blocks && ret == 0)
  45                 return -1;
  46
  47         return ret;
  48 }
  49
  50 /*
  51  * Set short name in directory entry
  52  */
  53 static void set_name(dir_entry *dirent, const char *filename)
  54 {
  55         char s_name[VFAT_MAXLEN_BYTES];
  56         char *period;
  57         int period_location, len, i, ext_num;
  58
  59         if (filename == NULL)
  60                 return;
  61
  62         len = strlen(filename);
  63         if (len == 0)
  64                 return;
  65
  66         strcpy(s_name, filename);
  67         uppercase(s_name, len);
  68
  69         period = strchr(s_name, '.');
  70         if (period == NULL) {
  71                 period_location = len;
  72                 ext_num = 0;
  73         } else {
  74                 period_location = period - s_name;
  75                 ext_num = len - period_location - 1;
  76         }
  77
  78         /* Pad spaces when the length of file name is shorter than eight */
  79         if (period_location < 8) {
  80                 memcpy(dirent->name, s_name, period_location);
  81                 for (i = period_location; i < 8; i++)
  82                         dirent->name[i] = ' ';
  83         } else if (period_location == 8) {
  84                 memcpy(dirent->name, s_name, period_location);
  85         } else {
  86                 memcpy(dirent->name, s_name, 6);
  87                 dirent->name[6] = '~';
  88                 dirent->name[7] = '1';
  89         }
  90
  91         if (ext_num < 3) {
  92                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
  93                 for (i = ext_num; i < 3; i++)
  94                         dirent->ext[i] = ' ';
  95         } else
  96                 memcpy(dirent->ext, s_name + period_location + 1, 3);
  97
  98         debug("name : %s\n", dirent->name);
  99         debug("ext : %s\n", dirent->ext);
 100 }
 101
 102 /*
 103  * Write fat buffer into block device
 104  */
 105 static int flush_dirty_fat_buffer(fsdata *mydata)
 106 {
 107         int getsize = FATBUFBLOCKS;
 108         __u32 fatlength = mydata->fatlength;
 109         __u8 *bufptr = mydata->fatbuf;
 110         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 111
 112         debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum,
 113               (int)mydata->fat_dirty);
 114
 115         if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1))
 116                 return 0;
 117
 118         /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 119         if (startblock + getsize > fatlength)
 120                 getsize = fatlength - startblock;
 121
 122         startblock += mydata->fat_sect;
 123
 124         /* Write FAT buf */
 125         if (disk_write(startblock, getsize, bufptr) < 0) {
 126                 debug("error: writing FAT blocks\n");
 127                 return -1;
 128         }
 129
 130         if (mydata->fats == 2) {
 131                 /* Update corresponding second FAT blocks */
 132                 startblock += mydata->fatlength;
 133                 if (disk_write(startblock, getsize, bufptr) < 0) {
 134                         debug("error: writing second FAT blocks\n");
 135                         return -1;
 136                 }
 137         }
 138         mydata->fat_dirty = 0;
 139
 140         return 0;
 141 }
 142
 143 /*
 144  * Set the file name information from 'name' into 'slotptr',
 145  */
 146 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 147 {
 148         int j, end_idx = 0;
 149
 150         for (j = 0; j <= 8; j += 2) {
 151                 if (name[*idx] == 0x00) {
 152                         slotptr->name0_4[j] = 0;
 153                         slotptr->name0_4[j + 1] = 0;
 154                         end_idx++;
 155                         goto name0_4;
 156                 }
 157                 slotptr->name0_4[j] = name[*idx];
 158                 (*idx)++;
 159                 end_idx++;
 160         }
 161         for (j = 0; j <= 10; j += 2) {
 162                 if (name[*idx] == 0x00) {
 163                         slotptr->name5_10[j] = 0;
 164                         slotptr->name5_10[j + 1] = 0;
 165                         end_idx++;
 166                         goto name5_10;
 167                 }
 168                 slotptr->name5_10[j] = name[*idx];
 169                 (*idx)++;
 170                 end_idx++;
 171         }
 172         for (j = 0; j <= 2; j += 2) {
 173                 if (name[*idx] == 0x00) {
 174                         slotptr->name11_12[j] = 0;
 175                         slotptr->name11_12[j + 1] = 0;
 176                         end_idx++;
 177                         goto name11_12;
 178                 }
 179                 slotptr->name11_12[j] = name[*idx];
 180                 (*idx)++;
 181                 end_idx++;
 182         }
 183
 184         if (name[*idx] == 0x00)
 185                 return 1;
 186
 187         return 0;
 188 /* Not used characters are filled with 0xff 0xff */
 189 name0_4:
 190         for (; end_idx < 5; end_idx++) {
 191                 slotptr->name0_4[end_idx * 2] = 0xff;
 192                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 193         }
 194         end_idx = 5;
 195 name5_10:
 196         end_idx -= 5;
 197         for (; end_idx < 6; end_idx++) {
 198                 slotptr->name5_10[end_idx * 2] = 0xff;
 199                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 200         }
 201         end_idx = 11;
 202 name11_12:
 203         end_idx -= 11;
 204         for (; end_idx < 2; end_idx++) {
 205                 slotptr->name11_12[end_idx * 2] = 0xff;
 206                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 207         }
 208
 209         return 1;
 210 }
 211
 212 static int new_dir_table(fat_itr *itr);
 213 static int flush_dir(fat_itr *itr);
 214
 215 /*
 216  * Fill dir_slot entries with appropriate name, id, and attr
 217  * 'itr' will point to a next entry
 218  */
 219 static int
 220 fill_dir_slot(fat_itr *itr, const char *l_name)
 221 {
 222         __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
 223         dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
 224         __u8 counter = 0, checksum;
 225         int idx = 0, ret;
 226
 227         /* Get short file name checksum value */
 228         checksum = mkcksum(itr->dent->name, itr->dent->ext);
 229
 230         do {
 231                 memset(slotptr, 0x00, sizeof(dir_slot));
 232                 ret = str2slot(slotptr, l_name, &idx);
 233                 slotptr->id = ++counter;
 234                 slotptr->attr = ATTR_VFAT;
 235                 slotptr->alias_checksum = checksum;
 236                 slotptr++;
 237         } while (ret == 0);
 238
 239         slotptr--;
 240         slotptr->id |= LAST_LONG_ENTRY_MASK;
 241
 242         while (counter >= 1) {
 243                 memcpy(itr->dent, slotptr, sizeof(dir_slot));
 244                 slotptr--;
 245                 counter--;
 246
 247                 if (itr->remaining == 0)
 248                         flush_dir(itr);
 249
 250                 /* allocate a cluster for more entries */
 251                 if (!fat_itr_next(itr))
 252                         if (!itr->dent &&
 253                             (!itr->is_root || itr->fsdata->fatsize == 32) &&
 254                             new_dir_table(itr))
 255                                 return -1;
 256         }
 257
 258         return 0;
 259 }
 260
 261 /*
 262  * Set the entry at index 'entry' in a FAT (12/16/32) table.
 263  */
 264 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 265 {
 266         __u32 bufnum, offset, off16;
 267         __u16 val1, val2;
 268
 269         switch (mydata->fatsize) {
 270         case 32:
 271                 bufnum = entry / FAT32BUFSIZE;
 272                 offset = entry - bufnum * FAT32BUFSIZE;
 273                 break;
 274         case 16:
 275                 bufnum = entry / FAT16BUFSIZE;
 276                 offset = entry - bufnum * FAT16BUFSIZE;
 277                 break;
 278         case 12:
 279                 bufnum = entry / FAT12BUFSIZE;
 280                 offset = entry - bufnum * FAT12BUFSIZE;
 281                 break;
 282         default:
 283                 /* Unsupported FAT size */
 284                 return -1;
 285         }
 286
 287         /* Read a new block of FAT entries into the cache. */
 288         if (bufnum != mydata->fatbufnum) {
 289                 int getsize = FATBUFBLOCKS;
 290                 __u8 *bufptr = mydata->fatbuf;
 291                 __u32 fatlength = mydata->fatlength;
 292                 __u32 startblock = bufnum * FATBUFBLOCKS;
 293
 294                 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 295                 if (startblock + getsize > fatlength)
 296                         getsize = fatlength - startblock;
 297
 298                 if (flush_dirty_fat_buffer(mydata) < 0)
 299                         return -1;
 300
 301                 startblock += mydata->fat_sect;
 302
 303                 if (disk_read(startblock, getsize, bufptr) < 0) {
 304                         debug("Error reading FAT blocks\n");
 305                         return -1;
 306                 }
 307                 mydata->fatbufnum = bufnum;
 308         }
 309
 310         /* Mark as dirty */
 311         mydata->fat_dirty = 1;
 312
 313         /* Set the actual entry */
 314         switch (mydata->fatsize) {
 315         case 32:
 316                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 317                 break;
 318         case 16:
 319                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 320                 break;
 321         case 12:
 322                 off16 = (offset * 3) / 4;
 323
 324                 switch (offset & 0x3) {
 325                 case 0:
 326                         val1 = cpu_to_le16(entry_value) & 0xfff;
 327                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
 328                         ((__u16 *)mydata->fatbuf)[off16] |= val1;
 329                         break;
 330                 case 1:
 331                         val1 = cpu_to_le16(entry_value) & 0xf;
 332                         val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
 333
 334                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
 335                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
 336
 337                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
 338                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 339                         break;
 340                 case 2:
 341                         val1 = cpu_to_le16(entry_value) & 0xff;
 342                         val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
 343
 344                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
 345                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
 346
 347                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
 348                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 349                         break;
 350                 case 3:
 351                         val1 = cpu_to_le16(entry_value) & 0xfff;
 352                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
 353                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
 354                         break;
 355                 default:
 356                         break;
 357                 }
 358
 359                 break;
 360         default:
 361                 return -1;
 362         }
 363
 364         return 0;
 365 }
 366
 367 /*
 368  * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
 369  * and link it to 'entry'. EOC marker is not set on returned entry.
 370  */
 371 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 372 {
 373         __u32 next_fat, next_entry = entry + 1;
 374
 375         while (1) {
 376                 next_fat = get_fatent(mydata, next_entry);
 377                 if (next_fat == 0) {
 378                         /* found free entry, link to entry */
 379                         set_fatent_value(mydata, entry, next_entry);
 380                         break;
 381                 }
 382                 next_entry++;
 383         }
 384         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 385                mydata->fatsize, entry, next_entry);
 386
 387         return next_entry;
 388 }
 389
 390 /**
 391  * set_sectors() - write data to sectors
 392  *
 393  * Write 'size' bytes from 'buffer' into the specified sector.
 394  *
 395  * @mydata:     data to be written
 396  * @startsect:  sector to be written to
 397  * @buffer:     data to be written
 398  * @size:       bytes to be written (but not more than the size of a cluster)
 399  * Return:      0 on success, -1 otherwise
 400  */
 401 static int
 402 set_sectors(fsdata *mydata, u32 startsect, u8 *buffer, u32 size)
 403 {
 404         u32 nsects = 0;
 405         int ret;
 406
 407         debug("startsect: %d\n", startsect);
 408
 409         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 410                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 411
 412                 debug("FAT: Misaligned buffer address (%p)\n", buffer);
 413
 414                 while (size >= mydata->sect_size) {
 415                         memcpy(tmpbuf, buffer, mydata->sect_size);
 416                         ret = disk_write(startsect++, 1, tmpbuf);
 417                         if (ret != 1) {
 418                                 debug("Error writing data (got %d)\n", ret);
 419                                 return -1;
 420                         }
 421
 422                         buffer += mydata->sect_size;
 423                         size -= mydata->sect_size;
 424                 }
 425         } else if (size >= mydata->sect_size) {
 426                 nsects = size / mydata->sect_size;
 427                 ret = disk_write(startsect, nsects, buffer);
 428                 if (ret != nsects) {
 429                         debug("Error writing data (got %d)\n", ret);
 430                         return -1;
 431                 }
 432
 433                 startsect += nsects;
 434                 buffer += nsects * mydata->sect_size;
 435                 size -= nsects * mydata->sect_size;
 436         }
 437
 438         if (size) {
 439                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 440                 /* Do not leak content of stack */
 441                 memset(tmpbuf, 0, mydata->sect_size);
 442                 memcpy(tmpbuf, buffer, size);
 443                 ret = disk_write(startsect, 1, tmpbuf);
 444                 if (ret != 1) {
 445                         debug("Error writing data (got %d)\n", ret);
 446                         return -1;
 447                 }
 448         }
 449
 450         return 0;
 451 }
 452
 453 /**
 454  * set_cluster() - write data to cluster
 455  *
 456  * Write 'size' bytes from 'buffer' into the specified cluster.
 457  *
 458  * @mydata:     data to be written
 459  * @clustnum:   cluster to be written to
 460  * @buffer:     data to be written
 461  * @size:       bytes to be written (but not more than the size of a cluster)
 462  * Return:      0 on success, -1 otherwise
 463  */
 464 static int
 465 set_cluster(fsdata *mydata, u32 clustnum, u8 *buffer, u32 size)
 466 {
 467         return set_sectors(mydata, clust_to_sect(mydata, clustnum),
 468                            buffer, size);
 469 }
 470
 471 static int
 472 flush_dir(fat_itr *itr)
 473 {
 474         fsdata *mydata = itr->fsdata;
 475         u32 startsect, sect_offset, nsects;
 476
 477         if (!itr->is_root || mydata->fatsize == 32)
 478                 return set_cluster(mydata, itr->clust, itr->block,
 479                                    mydata->clust_size * mydata->sect_size);
 480
 481         sect_offset = itr->clust * mydata->clust_size;
 482         startsect = mydata->rootdir_sect + sect_offset;
 483         /* do not write past the end of rootdir */
 484         nsects = min_t(u32, mydata->clust_size,
 485                        mydata->rootdir_size - sect_offset);
 486
 487         return set_sectors(mydata, startsect, itr->block,
 488                            nsects * mydata->sect_size);
 489 }
 490
 491 static __u8 tmpbuf_cluster[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
 492
 493 /*
 494  * Read and modify data on existing and consecutive cluster blocks
 495  */
 496 static int
 497 get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
 498                 loff_t size, loff_t *gotsize)
 499 {
 500         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 501         __u32 startsect;
 502         loff_t wsize;
 503         int clustcount, i, ret;
 504
 505         *gotsize = 0;
 506         if (!size)
 507                 return 0;
 508
 509         assert(pos < bytesperclust);
 510         startsect = clust_to_sect(mydata, clustnum);
 511
 512         debug("clustnum: %d, startsect: %d, pos: %lld\n",
 513               clustnum, startsect, pos);
 514
 515         /* partial write at beginning */
 516         if (pos) {
 517                 wsize = min(bytesperclust - pos, size);
 518                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 519                 if (ret != mydata->clust_size) {
 520                         debug("Error reading data (got %d)\n", ret);
 521                         return -1;
 522                 }
 523
 524                 memcpy(tmpbuf_cluster + pos, buffer, wsize);
 525                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 526                 if (ret != mydata->clust_size) {
 527                         debug("Error writing data (got %d)\n", ret);
 528                         return -1;
 529                 }
 530
 531                 size -= wsize;
 532                 buffer += wsize;
 533                 *gotsize += wsize;
 534
 535                 startsect += mydata->clust_size;
 536
 537                 if (!size)
 538                         return 0;
 539         }
 540
 541         /* full-cluster write */
 542         if (size >= bytesperclust) {
 543                 clustcount = lldiv(size, bytesperclust);
 544
 545                 if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
 546                         wsize = clustcount * bytesperclust;
 547                         ret = disk_write(startsect,
 548                                          clustcount * mydata->clust_size,
 549                                          buffer);
 550                         if (ret != clustcount * mydata->clust_size) {
 551                                 debug("Error writing data (got %d)\n", ret);
 552                                 return -1;
 553                         }
 554
 555                         size -= wsize;
 556                         buffer += wsize;
 557                         *gotsize += wsize;
 558
 559                         startsect += clustcount * mydata->clust_size;
 560                 } else {
 561                         for (i = 0; i < clustcount; i++) {
 562                                 memcpy(tmpbuf_cluster, buffer, bytesperclust);
 563                                 ret = disk_write(startsect,
 564                                                  mydata->clust_size,
 565                                                  tmpbuf_cluster);
 566                                 if (ret != mydata->clust_size) {
 567                                         debug("Error writing data (got %d)\n",
 568                                               ret);
 569                                         return -1;
 570                                 }
 571
 572                                 size -= bytesperclust;
 573                                 buffer += bytesperclust;
 574                                 *gotsize += bytesperclust;
 575
 576                                 startsect += mydata->clust_size;
 577                         }
 578                 }
 579         }
 580
 581         /* partial write at end */
 582         if (size) {
 583                 wsize = size;
 584                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 585                 if (ret != mydata->clust_size) {
 586                         debug("Error reading data (got %d)\n", ret);
 587                         return -1;
 588                 }
 589                 memcpy(tmpbuf_cluster, buffer, wsize);
 590                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 591                 if (ret != mydata->clust_size) {
 592                         debug("Error writing data (got %d)\n", ret);
 593                         return -1;
 594                 }
 595
 596                 size -= wsize;
 597                 buffer += wsize;
 598                 *gotsize += wsize;
 599         }
 600
 601         assert(!size);
 602
 603         return 0;
 604 }
 605
 606 /*
 607  * Find the first empty cluster
 608  */
 609 static int find_empty_cluster(fsdata *mydata)
 610 {
 611         __u32 fat_val, entry = 3;
 612
 613         while (1) {
 614                 fat_val = get_fatent(mydata, entry);
 615                 if (fat_val == 0)
 616                         break;
 617                 entry++;
 618         }
 619
 620         return entry;
 621 }
 622
 623 /*
 624  * Allocate a cluster for additional directory entries
 625  */
 626 static int new_dir_table(fat_itr *itr)
 627 {
 628         fsdata *mydata = itr->fsdata;
 629         int dir_newclust = 0;
 630         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 631
 632         dir_newclust = find_empty_cluster(mydata);
 633         set_fatent_value(mydata, itr->clust, dir_newclust);
 634         if (mydata->fatsize == 32)
 635                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 636         else if (mydata->fatsize == 16)
 637                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 638         else if (mydata->fatsize == 12)
 639                 set_fatent_value(mydata, dir_newclust, 0xff8);
 640
 641         itr->clust = dir_newclust;
 642         itr->next_clust = dir_newclust;
 643
 644         if (flush_dirty_fat_buffer(mydata) < 0)
 645                 return -1;
 646
 647         memset(itr->block, 0x00, bytesperclust);
 648
 649         itr->dent = (dir_entry *)itr->block;
 650         itr->last_cluster = 1;
 651         itr->remaining = bytesperclust / sizeof(dir_entry) - 1;
 652
 653         return 0;
 654 }
 655
 656 /*
 657  * Set empty cluster from 'entry' to the end of a file
 658  */
 659 static int clear_fatent(fsdata *mydata, __u32 entry)
 660 {
 661         __u32 fat_val;
 662
 663         while (!CHECK_CLUST(entry, mydata->fatsize)) {
 664                 fat_val = get_fatent(mydata, entry);
 665                 if (fat_val != 0)
 666                         set_fatent_value(mydata, entry, 0);
 667                 else
 668                         break;
 669
 670                 entry = fat_val;
 671         }
 672
 673         /* Flush fat buffer */
 674         if (flush_dirty_fat_buffer(mydata) < 0)
 675                 return -1;
 676
 677         return 0;
 678 }
 679
 680 /*
 681  * Set start cluster in directory entry
 682  */
 683 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 684                               __u32 start_cluster)
 685 {
 686         if (mydata->fatsize == 32)
 687                 dentptr->starthi =
 688                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 689         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 690 }
 691
 692 /*
 693  * Check whether adding a file makes the file system to
 694  * exceed the size of the block device
 695  * Return -1 when overflow occurs, otherwise return 0
 696  */
 697 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 698 {
 699         __u32 startsect, sect_num, offset;
 700
 701         if (clustnum > 0)
 702                 startsect = clust_to_sect(mydata, clustnum);
 703         else
 704                 startsect = mydata->rootdir_sect;
 705
 706         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 707
 708         if (offset != 0)
 709                 sect_num++;
 710
 711         if (startsect + sect_num > total_sector)
 712                 return -1;
 713         return 0;
 714 }
 715
 716 /*
 717  * Write at most 'maxsize' bytes from 'buffer' into
 718  * the file associated with 'dentptr'
 719  * Update the number of bytes written in *gotsize and return 0
 720  * or return -1 on fatal errors.
 721  */
 722 static int
 723 set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
 724              loff_t maxsize, loff_t *gotsize)
 725 {
 726         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 727         __u32 curclust = START(dentptr);
 728         __u32 endclust = 0, newclust = 0;
 729         u64 cur_pos, filesize;
 730         loff_t offset, actsize, wsize;
 731
 732         *gotsize = 0;
 733         filesize = pos + maxsize;
 734
 735         debug("%llu bytes\n", filesize);
 736
 737         if (!filesize) {
 738                 if (!curclust)
 739                         return 0;
 740                 if (!CHECK_CLUST(curclust, mydata->fatsize) ||
 741                     IS_LAST_CLUST(curclust, mydata->fatsize)) {
 742                         clear_fatent(mydata, curclust);
 743                         set_start_cluster(mydata, dentptr, 0);
 744                         return 0;
 745                 }
 746                 debug("curclust: 0x%x\n", curclust);
 747                 debug("Invalid FAT entry\n");
 748                 return -1;
 749         }
 750
 751         if (!curclust) {
 752                 assert(pos == 0);
 753                 goto set_clusters;
 754         }
 755
 756         /* go to cluster at pos */
 757         cur_pos = bytesperclust;
 758         while (1) {
 759                 if (pos <= cur_pos)
 760                         break;
 761                 if (IS_LAST_CLUST(curclust, mydata->fatsize))
 762                         break;
 763
 764                 newclust = get_fatent(mydata, curclust);
 765                 if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
 766                     CHECK_CLUST(newclust, mydata->fatsize)) {
 767                         debug("curclust: 0x%x\n", curclust);
 768                         debug("Invalid FAT entry\n");
 769                         return -1;
 770                 }
 771
 772                 cur_pos += bytesperclust;
 773                 curclust = newclust;
 774         }
 775         if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 776                 assert(pos == cur_pos);
 777                 goto set_clusters;
 778         }
 779
 780         assert(pos < cur_pos);
 781         cur_pos -= bytesperclust;
 782
 783         /* overwrite */
 784         assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
 785                !CHECK_CLUST(curclust, mydata->fatsize));
 786
 787         while (1) {
 788                 /* search for allocated consecutive clusters */
 789                 actsize = bytesperclust;
 790                 endclust = curclust;
 791                 while (1) {
 792                         if (filesize <= (cur_pos + actsize))
 793                                 break;
 794
 795                         newclust = get_fatent(mydata, endclust);
 796
 797                         if (newclust != endclust + 1)
 798                                 break;
 799                         if (IS_LAST_CLUST(newclust, mydata->fatsize))
 800                                 break;
 801                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 802                                 debug("curclust: 0x%x\n", curclust);
 803                                 debug("Invalid FAT entry\n");
 804                                 return -1;
 805                         }
 806
 807                         actsize += bytesperclust;
 808                         endclust = newclust;
 809                 }
 810
 811                 /* overwrite to <curclust..endclust> */
 812                 if (pos < cur_pos)
 813                         offset = 0;
 814                 else
 815                         offset = pos - cur_pos;
 816                 wsize = min(cur_pos + actsize, filesize) - pos;
 817                 if (get_set_cluster(mydata, curclust, offset,
 818                                     buffer, wsize, &actsize)) {
 819                         printf("Error get-and-setting cluster\n");
 820                         return -1;
 821                 }
 822                 buffer += wsize;
 823                 *gotsize += wsize;
 824                 cur_pos += offset + wsize;
 825
 826                 if (filesize <= cur_pos)
 827                         break;
 828
 829                 if (IS_LAST_CLUST(newclust, mydata->fatsize))
 830                         /* no more clusters */
 831                         break;
 832
 833                 curclust = newclust;
 834         }
 835
 836         if (filesize <= cur_pos) {
 837                 /* no more write */
 838                 newclust = get_fatent(mydata, endclust);
 839                 if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
 840                         /* truncate the rest */
 841                         clear_fatent(mydata, newclust);
 842
 843                         /* Mark end of file in FAT */
 844                         if (mydata->fatsize == 12)
 845                                 newclust = 0xfff;
 846                         else if (mydata->fatsize == 16)
 847                                 newclust = 0xffff;
 848                         else if (mydata->fatsize == 32)
 849                                 newclust = 0xfffffff;
 850                         set_fatent_value(mydata, endclust, newclust);
 851                 }
 852
 853                 return 0;
 854         }
 855
 856         curclust = endclust;
 857         filesize -= cur_pos;
 858         assert(!do_div(cur_pos, bytesperclust));
 859
 860 set_clusters:
 861         /* allocate and write */
 862         assert(!pos);
 863
 864         /* Assure that curclust is valid */
 865         if (!curclust) {
 866                 curclust = find_empty_cluster(mydata);
 867                 set_start_cluster(mydata, dentptr, curclust);
 868         } else {
 869                 newclust = get_fatent(mydata, curclust);
 870
 871                 if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
 872                         newclust = determine_fatent(mydata, curclust);
 873                         set_fatent_value(mydata, curclust, newclust);
 874                         curclust = newclust;
 875                 } else {
 876                         debug("error: something wrong\n");
 877                         return -1;
 878                 }
 879         }
 880
 881         /* TODO: already partially written */
 882         if (check_overflow(mydata, curclust, filesize)) {
 883                 printf("Error: no space left: %llu\n", filesize);
 884                 return -1;
 885         }
 886
 887         actsize = bytesperclust;
 888         endclust = curclust;
 889         do {
 890                 /* search for consecutive clusters */
 891                 while (actsize < filesize) {
 892                         newclust = determine_fatent(mydata, endclust);
 893
 894                         if ((newclust - 1) != endclust)
 895                                 /* write to <curclust..endclust> */
 896                                 goto getit;
 897
 898                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 899                                 debug("newclust: 0x%x\n", newclust);
 900                                 debug("Invalid FAT entry\n");
 901                                 return 0;
 902                         }
 903                         endclust = newclust;
 904                         actsize += bytesperclust;
 905                 }
 906
 907                 /* set remaining bytes */
 908                 actsize = filesize;
 909                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 910                         debug("error: writing cluster\n");
 911                         return -1;
 912                 }
 913                 *gotsize += actsize;
 914
 915                 /* Mark end of file in FAT */
 916                 if (mydata->fatsize == 12)
 917                         newclust = 0xfff;
 918                 else if (mydata->fatsize == 16)
 919                         newclust = 0xffff;
 920                 else if (mydata->fatsize == 32)
 921                         newclust = 0xfffffff;
 922                 set_fatent_value(mydata, endclust, newclust);
 923
 924                 return 0;
 925 getit:
 926                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 927                         debug("error: writing cluster\n");
 928                         return -1;
 929                 }
 930                 *gotsize += actsize;
 931                 filesize -= actsize;
 932                 buffer += actsize;
 933
 934                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 935                         debug("newclust: 0x%x\n", newclust);
 936                         debug("Invalid FAT entry\n");
 937                         return 0;
 938                 }
 939                 actsize = bytesperclust;
 940                 curclust = endclust = newclust;
 941         } while (1);
 942
 943         return 0;
 944 }
 945
 946 /*
 947  * Fill dir_entry
 948  */
 949 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 950         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 951 {
 952         set_start_cluster(mydata, dentptr, start_cluster);
 953         dentptr->size = cpu_to_le32(size);
 954
 955         dentptr->attr = attr;
 956
 957         set_name(dentptr, filename);
 958 }
 959
 960 /*
 961  * Find a directory entry based on filename or start cluster number
 962  * If the directory entry is not found,
 963  * the new position for writing a directory entry will be returned
 964  */
 965 static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
 966 {
 967         int match = 0;
 968
 969         while (fat_itr_next(itr)) {
 970                 /* check both long and short name: */
 971                 if (!strcasecmp(filename, itr->name))
 972                         match = 1;
 973                 else if (itr->name != itr->s_name &&
 974                          !strcasecmp(filename, itr->s_name))
 975                         match = 1;
 976
 977                 if (!match)
 978                         continue;
 979
 980                 if (itr->dent->name[0] == '\0')
 981                         return NULL;
 982                 else
 983                         return itr->dent;
 984         }
 985
 986         /* allocate a cluster for more entries */
 987         if (!itr->dent &&
 988             (!itr->is_root || itr->fsdata->fatsize == 32) &&
 989             new_dir_table(itr))
 990                 /* indicate that allocating dent failed */
 991                 itr->dent = NULL;
 992
 993         return NULL;
 994 }
 995
 996 static int split_filename(char *filename, char **dirname, char **basename)
 997 {
 998         char *p, *last_slash, *last_slash_cont;
 999
1000 again:
1001         p = filename;
1002         last_slash = NULL;
1003         last_slash_cont = NULL;
1004         while (*p) {
1005                 if (ISDIRDELIM(*p)) {
1006                         last_slash = p;
1007                         last_slash_cont = p;
1008                         /* continuous slashes */
1009                         while (ISDIRDELIM(*p))
1010                                 last_slash_cont = p++;
1011                         if (!*p)
1012                                 break;
1013                 }
1014                 p++;
1015         }
1016
1017         if (last_slash) {
1018                 if (last_slash_cont == (filename + strlen(filename) - 1)) {
1019                         /* remove trailing slashes */
1020                         *last_slash = '\0';
1021                         goto again;
1022                 }
1023
1024                 if (last_slash == filename) {
1025                         /* avoid ""(null) directory */
1026                         *dirname = "/";
1027                 } else {
1028                         *last_slash = '\0';
1029                         *dirname = filename;
1030                 }
1031
1032                 *last_slash_cont = '\0';
1033                 *basename = last_slash_cont + 1;
1034         } else {
1035                 *dirname = "/"; /* root by default */
1036                 *basename = filename;
1037         }
1038
1039         return 0;
1040 }
1041
1042 /**
1043  * normalize_longname() - check long file name and convert to lower case
1044  *
1045  * We assume here that the FAT file system is using an 8bit code page.
1046  * Linux typically uses CP437, EDK2 assumes CP1250.
1047  *
1048  * @l_filename: preallocated buffer receiving the normalized name
1049  * @filename:   filename to normalize
1050  * Return:      0 on success, -1 on failure
1051  */
1052 static int normalize_longname(char *l_filename, const char *filename)
1053 {
1054         const char *p, illegal[] = "<>:\"/\\|?*";
1055
1056         if (strlen(filename) >= VFAT_MAXLEN_BYTES)
1057                 return -1;
1058
1059         for (p = filename; *p; ++p) {
1060                 if ((unsigned char)*p < 0x20)
1061                         return -1;
1062                 if (strchr(illegal, *p))
1063                         return -1;
1064         }
1065
1066         strcpy(l_filename, filename);
1067         downcase(l_filename, VFAT_MAXLEN_BYTES);
1068
1069         return 0;
1070 }
1071
1072 int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
1073                       loff_t size, loff_t *actwrite)
1074 {
1075         dir_entry *retdent;
1076         fsdata datablock = { .fatbuf = NULL, };
1077         fsdata *mydata = &datablock;
1078         fat_itr *itr = NULL;
1079         int ret = -1;
1080         char *filename_copy, *parent, *basename;
1081         char l_filename[VFAT_MAXLEN_BYTES];
1082
1083         debug("writing %s\n", filename);
1084
1085         filename_copy = strdup(filename);
1086         if (!filename_copy)
1087                 return -ENOMEM;
1088
1089         split_filename(filename_copy, &parent, &basename);
1090         if (!strlen(basename)) {
1091                 ret = -EINVAL;
1092                 goto exit;
1093         }
1094
1095         filename = basename;
1096         if (normalize_longname(l_filename, filename)) {
1097                 printf("FAT: illegal filename (%s)\n", filename);
1098                 ret = -EINVAL;
1099                 goto exit;
1100         }
1101
1102         itr = malloc_cache_aligned(sizeof(fat_itr));
1103         if (!itr) {
1104                 ret = -ENOMEM;
1105                 goto exit;
1106         }
1107
1108         ret = fat_itr_root(itr, &datablock);
1109         if (ret)
1110                 goto exit;
1111
1112         total_sector = datablock.total_sect;
1113
1114         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1115         if (ret) {
1116                 printf("%s: doesn't exist (%d)\n", parent, ret);
1117                 goto exit;
1118         }
1119
1120         retdent = find_directory_entry(itr, l_filename);
1121
1122         if (retdent) {
1123                 if (fat_itr_isdir(itr)) {
1124                         ret = -EISDIR;
1125                         goto exit;
1126                 }
1127
1128                 /* A file exists */
1129                 if (pos == -1)
1130                         /* Append to the end */
1131                         pos = FAT2CPU32(retdent->size);
1132                 if (pos > retdent->size) {
1133                         /* No hole allowed */
1134                         ret = -EINVAL;
1135                         goto exit;
1136                 }
1137
1138                 /* Update file size in a directory entry */
1139                 retdent->size = cpu_to_le32(pos + size);
1140         } else {
1141                 /* Create a new file */
1142
1143                 if (itr->is_root) {
1144                         /* root dir cannot have "." or ".." */
1145                         if (!strcmp(l_filename, ".") ||
1146                             !strcmp(l_filename, "..")) {
1147                                 ret = -EINVAL;
1148                                 goto exit;
1149                         }
1150                 }
1151
1152                 if (!itr->dent) {
1153                         printf("Error: allocating new dir entry\n");
1154                         ret = -EIO;
1155                         goto exit;
1156                 }
1157
1158                 if (pos) {
1159                         /* No hole allowed */
1160                         ret = -EINVAL;
1161                         goto exit;
1162                 }
1163
1164                 memset(itr->dent, 0, sizeof(*itr->dent));
1165
1166                 /* Calculate checksum for short name */
1167                 set_name(itr->dent, filename);
1168
1169                 /* Set long name entries */
1170                 if (fill_dir_slot(itr, filename)) {
1171                         ret = -EIO;
1172                         goto exit;
1173                 }
1174
1175                 /* Set short name entry */
1176                 fill_dentry(itr->fsdata, itr->dent, filename, 0, size, 0x20);
1177
1178                 retdent = itr->dent;
1179         }
1180
1181         ret = set_contents(mydata, retdent, pos, buffer, size, actwrite);
1182         if (ret < 0) {
1183                 printf("Error: writing contents\n");
1184                 ret = -EIO;
1185                 goto exit;
1186         }
1187         debug("attempt to write 0x%llx bytes\n", *actwrite);
1188
1189         /* Flush fat buffer */
1190         ret = flush_dirty_fat_buffer(mydata);
1191         if (ret) {
1192                 printf("Error: flush fat buffer\n");
1193                 ret = -EIO;
1194                 goto exit;
1195         }
1196
1197         /* Write directory table to device */
1198         ret = flush_dir(itr);
1199         if (ret) {
1200                 printf("Error: writing directory entry\n");
1201                 ret = -EIO;
1202         }
1203
1204 exit:
1205         free(filename_copy);
1206         free(mydata->fatbuf);
1207         free(itr);
1208         return ret;
1209 }
1210
1211 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1212                    loff_t maxsize, loff_t *actwrite)
1213 {
1214         return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
1215 }
1216
1217 static int fat_dir_entries(fat_itr *itr)
1218 {
1219         fat_itr *dirs;
1220         fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
1221                                                 /* for FATBUFSIZE */
1222         int count;
1223
1224         dirs = malloc_cache_aligned(sizeof(fat_itr));
1225         if (!dirs) {
1226                 debug("Error: allocating memory\n");
1227                 count = -ENOMEM;
1228                 goto exit;
1229         }
1230
1231         /* duplicate fsdata */
1232         fat_itr_child(dirs, itr);
1233         fsdata = *dirs->fsdata;
1234
1235         /* allocate local fat buffer */
1236         fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
1237         if (!fsdata.fatbuf) {
1238                 debug("Error: allocating memory\n");
1239                 count = -ENOMEM;
1240                 goto exit;
1241         }
1242         fsdata.fatbufnum = -1;
1243         dirs->fsdata = &fsdata;
1244
1245         for (count = 0; fat_itr_next(dirs); count++)
1246                 ;
1247
1248 exit:
1249         free(fsdata.fatbuf);
1250         free(dirs);
1251         return count;
1252 }
1253
1254 static int delete_dentry(fat_itr *itr)
1255 {
1256         fsdata *mydata = itr->fsdata;
1257         dir_entry *dentptr = itr->dent;
1258
1259         /* free cluster blocks */
1260         clear_fatent(mydata, START(dentptr));
1261         if (flush_dirty_fat_buffer(mydata) < 0) {
1262                 printf("Error: flush fat buffer\n");
1263                 return -EIO;
1264         }
1265
1266         /*
1267          * update a directory entry
1268          * TODO:
1269          *  - long file name support
1270          *  - find and mark the "new" first invalid entry as name[0]=0x00
1271          */
1272         memset(dentptr, 0, sizeof(*dentptr));
1273         dentptr->name[0] = 0xe5;
1274
1275         if (flush_dir(itr)) {
1276                 printf("error: writing directory entry\n");
1277                 return -EIO;
1278         }
1279
1280         return 0;
1281 }
1282
1283 int fat_unlink(const char *filename)
1284 {
1285         fsdata fsdata = { .fatbuf = NULL, };
1286         fat_itr *itr = NULL;
1287         int n_entries, ret;
1288         char *filename_copy, *dirname, *basename;
1289
1290         filename_copy = strdup(filename);
1291         if (!filename_copy) {
1292                 printf("Error: allocating memory\n");
1293                 ret = -ENOMEM;
1294                 goto exit;
1295         }
1296         split_filename(filename_copy, &dirname, &basename);
1297
1298         if (!strcmp(dirname, "/") && !strcmp(basename, "")) {
1299                 printf("Error: cannot remove root\n");
1300                 ret = -EINVAL;
1301                 goto exit;
1302         }
1303
1304         itr = malloc_cache_aligned(sizeof(fat_itr));
1305         if (!itr) {
1306                 printf("Error: allocating memory\n");
1307                 ret = -ENOMEM;
1308                 goto exit;
1309         }
1310
1311         ret = fat_itr_root(itr, &fsdata);
1312         if (ret)
1313                 goto exit;
1314
1315         total_sector = fsdata.total_sect;
1316
1317         ret = fat_itr_resolve(itr, dirname, TYPE_DIR);
1318         if (ret) {
1319                 printf("%s: doesn't exist (%d)\n", dirname, ret);
1320                 ret = -ENOENT;
1321                 goto exit;
1322         }
1323
1324         if (!find_directory_entry(itr, basename)) {
1325                 printf("%s: doesn't exist\n", basename);
1326                 ret = -ENOENT;
1327                 goto exit;
1328         }
1329
1330         if (fat_itr_isdir(itr)) {
1331                 n_entries = fat_dir_entries(itr);
1332                 if (n_entries < 0) {
1333                         ret = n_entries;
1334                         goto exit;
1335                 }
1336                 if (n_entries > 2) {
1337                         printf("Error: directory is not empty: %d\n",
1338                                n_entries);
1339                         ret = -EINVAL;
1340                         goto exit;
1341                 }
1342         }
1343
1344         ret = delete_dentry(itr);
1345
1346 exit:
1347         free(fsdata.fatbuf);
1348         free(itr);
1349         free(filename_copy);
1350
1351         return ret;
1352 }
1353
1354 int fat_mkdir(const char *new_dirname)
1355 {
1356         dir_entry *retdent;
1357         fsdata datablock = { .fatbuf = NULL, };
1358         fsdata *mydata = &datablock;
1359         fat_itr *itr = NULL;
1360         char *dirname_copy, *parent, *dirname;
1361         char l_dirname[VFAT_MAXLEN_BYTES];
1362         int ret = -1;
1363         loff_t actwrite;
1364         unsigned int bytesperclust;
1365         dir_entry *dotdent = NULL;
1366
1367         dirname_copy = strdup(new_dirname);
1368         if (!dirname_copy)
1369                 goto exit;
1370
1371         split_filename(dirname_copy, &parent, &dirname);
1372         if (!strlen(dirname)) {
1373                 ret = -EINVAL;
1374                 goto exit;
1375         }
1376
1377         if (normalize_longname(l_dirname, dirname)) {
1378                 printf("FAT: illegal filename (%s)\n", dirname);
1379                 ret = -EINVAL;
1380                 goto exit;
1381         }
1382
1383         itr = malloc_cache_aligned(sizeof(fat_itr));
1384         if (!itr) {
1385                 ret = -ENOMEM;
1386                 goto exit;
1387         }
1388
1389         ret = fat_itr_root(itr, &datablock);
1390         if (ret)
1391                 goto exit;
1392
1393         total_sector = datablock.total_sect;
1394
1395         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1396         if (ret) {
1397                 printf("%s: doesn't exist (%d)\n", parent, ret);
1398                 goto exit;
1399         }
1400
1401         retdent = find_directory_entry(itr, l_dirname);
1402
1403         if (retdent) {
1404                 printf("%s: already exists\n", l_dirname);
1405                 ret = -EEXIST;
1406                 goto exit;
1407         } else {
1408                 if (itr->is_root) {
1409                         /* root dir cannot have "." or ".." */
1410                         if (!strcmp(l_dirname, ".") ||
1411                             !strcmp(l_dirname, "..")) {
1412                                 ret = -EINVAL;
1413                                 goto exit;
1414                         }
1415                 }
1416
1417                 if (!itr->dent) {
1418                         printf("Error: allocating new dir entry\n");
1419                         ret = -EIO;
1420                         goto exit;
1421                 }
1422
1423                 memset(itr->dent, 0, sizeof(*itr->dent));
1424
1425                 /* Set short name to set alias checksum field in dir_slot */
1426                 set_name(itr->dent, dirname);
1427                 fill_dir_slot(itr, dirname);
1428
1429                 /* Set attribute as archive for regular file */
1430                 fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0,
1431                             ATTR_DIR | ATTR_ARCH);
1432
1433                 retdent = itr->dent;
1434         }
1435
1436         /* Default entries */
1437         bytesperclust = mydata->clust_size * mydata->sect_size;
1438         dotdent = malloc_cache_aligned(bytesperclust);
1439         if (!dotdent) {
1440                 ret = -ENOMEM;
1441                 goto exit;
1442         }
1443         memset(dotdent, 0, bytesperclust);
1444
1445         memcpy(dotdent[0].name, ".       ", 8);
1446         memcpy(dotdent[0].ext, "   ", 3);
1447         dotdent[0].attr = ATTR_DIR | ATTR_ARCH;
1448
1449         memcpy(dotdent[1].name, "..      ", 8);
1450         memcpy(dotdent[1].ext, "   ", 3);
1451         dotdent[1].attr = ATTR_DIR | ATTR_ARCH;
1452         set_start_cluster(mydata, &dotdent[1], itr->start_clust);
1453
1454         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1455                            bytesperclust, &actwrite);
1456         if (ret < 0) {
1457                 printf("Error: writing contents\n");
1458                 goto exit;
1459         }
1460         /* Write twice for "." */
1461         set_start_cluster(mydata, &dotdent[0], START(retdent));
1462         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1463                            bytesperclust, &actwrite);
1464         if (ret < 0) {
1465                 printf("Error: writing contents\n");
1466                 goto exit;
1467         }
1468
1469         /* Flush fat buffer */
1470         ret = flush_dirty_fat_buffer(mydata);
1471         if (ret) {
1472                 printf("Error: flush fat buffer\n");
1473                 goto exit;
1474         }
1475
1476         /* Write directory table to device */
1477         ret = flush_dir(itr);
1478         if (ret)
1479                 printf("Error: writing directory entry\n");
1480
1481 exit:
1482         free(dirname_copy);
1483         free(mydata->fatbuf);
1484         free(itr);
1485         free(dotdent);
1486         return ret;
1487 }