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_t(unsigned long long, actsize, filesize - cur_pos);
 817                 wsize -= offset;
 818
 819                 if (get_set_cluster(mydata, curclust, offset,
 820                                     buffer, wsize, &actsize)) {
 821                         printf("Error get-and-setting cluster\n");
 822                         return -1;
 823                 }
 824                 buffer += wsize;
 825                 *gotsize += wsize;
 826                 cur_pos += offset + wsize;
 827
 828                 if (filesize <= cur_pos)
 829                         break;
 830
 831                 if (IS_LAST_CLUST(newclust, mydata->fatsize))
 832                         /* no more clusters */
 833                         break;
 834
 835                 curclust = newclust;
 836         }
 837
 838         if (filesize <= cur_pos) {
 839                 /* no more write */
 840                 newclust = get_fatent(mydata, endclust);
 841                 if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
 842                         /* truncate the rest */
 843                         clear_fatent(mydata, newclust);
 844
 845                         /* Mark end of file in FAT */
 846                         if (mydata->fatsize == 12)
 847                                 newclust = 0xfff;
 848                         else if (mydata->fatsize == 16)
 849                                 newclust = 0xffff;
 850                         else if (mydata->fatsize == 32)
 851                                 newclust = 0xfffffff;
 852                         set_fatent_value(mydata, endclust, newclust);
 853                 }
 854
 855                 return 0;
 856         }
 857
 858         curclust = endclust;
 859         filesize -= cur_pos;
 860         assert(!do_div(cur_pos, bytesperclust));
 861
 862 set_clusters:
 863         /* allocate and write */
 864         assert(!pos);
 865
 866         /* Assure that curclust is valid */
 867         if (!curclust) {
 868                 curclust = find_empty_cluster(mydata);
 869                 set_start_cluster(mydata, dentptr, curclust);
 870         } else {
 871                 newclust = get_fatent(mydata, curclust);
 872
 873                 if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
 874                         newclust = determine_fatent(mydata, curclust);
 875                         set_fatent_value(mydata, curclust, newclust);
 876                         curclust = newclust;
 877                 } else {
 878                         debug("error: something wrong\n");
 879                         return -1;
 880                 }
 881         }
 882
 883         /* TODO: already partially written */
 884         if (check_overflow(mydata, curclust, filesize)) {
 885                 printf("Error: no space left: %llu\n", filesize);
 886                 return -1;
 887         }
 888
 889         actsize = bytesperclust;
 890         endclust = curclust;
 891         do {
 892                 /* search for consecutive clusters */
 893                 while (actsize < filesize) {
 894                         newclust = determine_fatent(mydata, endclust);
 895
 896                         if ((newclust - 1) != endclust)
 897                                 /* write to <curclust..endclust> */
 898                                 goto getit;
 899
 900                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 901                                 debug("newclust: 0x%x\n", newclust);
 902                                 debug("Invalid FAT entry\n");
 903                                 return 0;
 904                         }
 905                         endclust = newclust;
 906                         actsize += bytesperclust;
 907                 }
 908
 909                 /* set remaining bytes */
 910                 actsize = filesize;
 911                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 912                         debug("error: writing cluster\n");
 913                         return -1;
 914                 }
 915                 *gotsize += actsize;
 916
 917                 /* Mark end of file in FAT */
 918                 if (mydata->fatsize == 12)
 919                         newclust = 0xfff;
 920                 else if (mydata->fatsize == 16)
 921                         newclust = 0xffff;
 922                 else if (mydata->fatsize == 32)
 923                         newclust = 0xfffffff;
 924                 set_fatent_value(mydata, endclust, newclust);
 925
 926                 return 0;
 927 getit:
 928                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 929                         debug("error: writing cluster\n");
 930                         return -1;
 931                 }
 932                 *gotsize += actsize;
 933                 filesize -= actsize;
 934                 buffer += actsize;
 935
 936                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 937                         debug("newclust: 0x%x\n", newclust);
 938                         debug("Invalid FAT entry\n");
 939                         return 0;
 940                 }
 941                 actsize = bytesperclust;
 942                 curclust = endclust = newclust;
 943         } while (1);
 944
 945         return 0;
 946 }
 947
 948 /*
 949  * Fill dir_entry
 950  */
 951 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 952         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 953 {
 954         set_start_cluster(mydata, dentptr, start_cluster);
 955         dentptr->size = cpu_to_le32(size);
 956
 957         dentptr->attr = attr;
 958
 959         set_name(dentptr, filename);
 960 }
 961
 962 /*
 963  * Find a directory entry based on filename or start cluster number
 964  * If the directory entry is not found,
 965  * the new position for writing a directory entry will be returned
 966  */
 967 static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
 968 {
 969         int match = 0;
 970
 971         while (fat_itr_next(itr)) {
 972                 /* check both long and short name: */
 973                 if (!strcasecmp(filename, itr->name))
 974                         match = 1;
 975                 else if (itr->name != itr->s_name &&
 976                          !strcasecmp(filename, itr->s_name))
 977                         match = 1;
 978
 979                 if (!match)
 980                         continue;
 981
 982                 if (itr->dent->name[0] == '\0')
 983                         return NULL;
 984                 else
 985                         return itr->dent;
 986         }
 987
 988         /* allocate a cluster for more entries */
 989         if (!itr->dent &&
 990             (!itr->is_root || itr->fsdata->fatsize == 32) &&
 991             new_dir_table(itr))
 992                 /* indicate that allocating dent failed */
 993                 itr->dent = NULL;
 994
 995         return NULL;
 996 }
 997
 998 static int split_filename(char *filename, char **dirname, char **basename)
 999 {
1000         char *p, *last_slash, *last_slash_cont;
1001
1002 again:
1003         p = filename;
1004         last_slash = NULL;
1005         last_slash_cont = NULL;
1006         while (*p) {
1007                 if (ISDIRDELIM(*p)) {
1008                         last_slash = p;
1009                         last_slash_cont = p;
1010                         /* continuous slashes */
1011                         while (ISDIRDELIM(*p))
1012                                 last_slash_cont = p++;
1013                         if (!*p)
1014                                 break;
1015                 }
1016                 p++;
1017         }
1018
1019         if (last_slash) {
1020                 if (last_slash_cont == (filename + strlen(filename) - 1)) {
1021                         /* remove trailing slashes */
1022                         *last_slash = '\0';
1023                         goto again;
1024                 }
1025
1026                 if (last_slash == filename) {
1027                         /* avoid ""(null) directory */
1028                         *dirname = "/";
1029                 } else {
1030                         *last_slash = '\0';
1031                         *dirname = filename;
1032                 }
1033
1034                 *last_slash_cont = '\0';
1035                 *basename = last_slash_cont + 1;
1036         } else {
1037                 *dirname = "/"; /* root by default */
1038                 *basename = filename;
1039         }
1040
1041         return 0;
1042 }
1043
1044 /**
1045  * normalize_longname() - check long file name and convert to lower case
1046  *
1047  * We assume here that the FAT file system is using an 8bit code page.
1048  * Linux typically uses CP437, EDK2 assumes CP1250.
1049  *
1050  * @l_filename: preallocated buffer receiving the normalized name
1051  * @filename:   filename to normalize
1052  * Return:      0 on success, -1 on failure
1053  */
1054 static int normalize_longname(char *l_filename, const char *filename)
1055 {
1056         const char *p, illegal[] = "<>:\"/\\|?*";
1057
1058         if (strlen(filename) >= VFAT_MAXLEN_BYTES)
1059                 return -1;
1060
1061         for (p = filename; *p; ++p) {
1062                 if ((unsigned char)*p < 0x20)
1063                         return -1;
1064                 if (strchr(illegal, *p))
1065                         return -1;
1066         }
1067
1068         strcpy(l_filename, filename);
1069         downcase(l_filename, VFAT_MAXLEN_BYTES);
1070
1071         return 0;
1072 }
1073
1074 int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
1075                       loff_t size, loff_t *actwrite)
1076 {
1077         dir_entry *retdent;
1078         fsdata datablock = { .fatbuf = NULL, };
1079         fsdata *mydata = &datablock;
1080         fat_itr *itr = NULL;
1081         int ret = -1;
1082         char *filename_copy, *parent, *basename;
1083         char l_filename[VFAT_MAXLEN_BYTES];
1084
1085         debug("writing %s\n", filename);
1086
1087         filename_copy = strdup(filename);
1088         if (!filename_copy)
1089                 return -ENOMEM;
1090
1091         split_filename(filename_copy, &parent, &basename);
1092         if (!strlen(basename)) {
1093                 ret = -EINVAL;
1094                 goto exit;
1095         }
1096
1097         filename = basename;
1098         if (normalize_longname(l_filename, filename)) {
1099                 printf("FAT: illegal filename (%s)\n", filename);
1100                 ret = -EINVAL;
1101                 goto exit;
1102         }
1103
1104         itr = malloc_cache_aligned(sizeof(fat_itr));
1105         if (!itr) {
1106                 ret = -ENOMEM;
1107                 goto exit;
1108         }
1109
1110         ret = fat_itr_root(itr, &datablock);
1111         if (ret)
1112                 goto exit;
1113
1114         total_sector = datablock.total_sect;
1115
1116         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1117         if (ret) {
1118                 printf("%s: doesn't exist (%d)\n", parent, ret);
1119                 goto exit;
1120         }
1121
1122         retdent = find_directory_entry(itr, l_filename);
1123
1124         if (retdent) {
1125                 if (fat_itr_isdir(itr)) {
1126                         ret = -EISDIR;
1127                         goto exit;
1128                 }
1129
1130                 /* A file exists */
1131                 if (pos == -1)
1132                         /* Append to the end */
1133                         pos = FAT2CPU32(retdent->size);
1134                 if (pos > retdent->size) {
1135                         /* No hole allowed */
1136                         ret = -EINVAL;
1137                         goto exit;
1138                 }
1139
1140                 /* Update file size in a directory entry */
1141                 retdent->size = cpu_to_le32(pos + size);
1142         } else {
1143                 /* Create a new file */
1144
1145                 if (itr->is_root) {
1146                         /* root dir cannot have "." or ".." */
1147                         if (!strcmp(l_filename, ".") ||
1148                             !strcmp(l_filename, "..")) {
1149                                 ret = -EINVAL;
1150                                 goto exit;
1151                         }
1152                 }
1153
1154                 if (!itr->dent) {
1155                         printf("Error: allocating new dir entry\n");
1156                         ret = -EIO;
1157                         goto exit;
1158                 }
1159
1160                 if (pos) {
1161                         /* No hole allowed */
1162                         ret = -EINVAL;
1163                         goto exit;
1164                 }
1165
1166                 memset(itr->dent, 0, sizeof(*itr->dent));
1167
1168                 /* Calculate checksum for short name */
1169                 set_name(itr->dent, filename);
1170
1171                 /* Set long name entries */
1172                 if (fill_dir_slot(itr, filename)) {
1173                         ret = -EIO;
1174                         goto exit;
1175                 }
1176
1177                 /* Set short name entry */
1178                 fill_dentry(itr->fsdata, itr->dent, filename, 0, size, 0x20);
1179
1180                 retdent = itr->dent;
1181         }
1182
1183         ret = set_contents(mydata, retdent, pos, buffer, size, actwrite);
1184         if (ret < 0) {
1185                 printf("Error: writing contents\n");
1186                 ret = -EIO;
1187                 goto exit;
1188         }
1189         debug("attempt to write 0x%llx bytes\n", *actwrite);
1190
1191         /* Flush fat buffer */
1192         ret = flush_dirty_fat_buffer(mydata);
1193         if (ret) {
1194                 printf("Error: flush fat buffer\n");
1195                 ret = -EIO;
1196                 goto exit;
1197         }
1198
1199         /* Write directory table to device */
1200         ret = flush_dir(itr);
1201         if (ret) {
1202                 printf("Error: writing directory entry\n");
1203                 ret = -EIO;
1204         }
1205
1206 exit:
1207         free(filename_copy);
1208         free(mydata->fatbuf);
1209         free(itr);
1210         return ret;
1211 }
1212
1213 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1214                    loff_t maxsize, loff_t *actwrite)
1215 {
1216         return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
1217 }
1218
1219 static int fat_dir_entries(fat_itr *itr)
1220 {
1221         fat_itr *dirs;
1222         fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
1223                                                 /* for FATBUFSIZE */
1224         int count;
1225
1226         dirs = malloc_cache_aligned(sizeof(fat_itr));
1227         if (!dirs) {
1228                 debug("Error: allocating memory\n");
1229                 count = -ENOMEM;
1230                 goto exit;
1231         }
1232
1233         /* duplicate fsdata */
1234         fat_itr_child(dirs, itr);
1235         fsdata = *dirs->fsdata;
1236
1237         /* allocate local fat buffer */
1238         fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
1239         if (!fsdata.fatbuf) {
1240                 debug("Error: allocating memory\n");
1241                 count = -ENOMEM;
1242                 goto exit;
1243         }
1244         fsdata.fatbufnum = -1;
1245         dirs->fsdata = &fsdata;
1246
1247         for (count = 0; fat_itr_next(dirs); count++)
1248                 ;
1249
1250 exit:
1251         free(fsdata.fatbuf);
1252         free(dirs);
1253         return count;
1254 }
1255
1256 static int delete_dentry(fat_itr *itr)
1257 {
1258         fsdata *mydata = itr->fsdata;
1259         dir_entry *dentptr = itr->dent;
1260
1261         /* free cluster blocks */
1262         clear_fatent(mydata, START(dentptr));
1263         if (flush_dirty_fat_buffer(mydata) < 0) {
1264                 printf("Error: flush fat buffer\n");
1265                 return -EIO;
1266         }
1267
1268         /*
1269          * update a directory entry
1270          * TODO:
1271          *  - long file name support
1272          *  - find and mark the "new" first invalid entry as name[0]=0x00
1273          */
1274         memset(dentptr, 0, sizeof(*dentptr));
1275         dentptr->name[0] = 0xe5;
1276
1277         if (flush_dir(itr)) {
1278                 printf("error: writing directory entry\n");
1279                 return -EIO;
1280         }
1281
1282         return 0;
1283 }
1284
1285 int fat_unlink(const char *filename)
1286 {
1287         fsdata fsdata = { .fatbuf = NULL, };
1288         fat_itr *itr = NULL;
1289         int n_entries, ret;
1290         char *filename_copy, *dirname, *basename;
1291
1292         filename_copy = strdup(filename);
1293         if (!filename_copy) {
1294                 printf("Error: allocating memory\n");
1295                 ret = -ENOMEM;
1296                 goto exit;
1297         }
1298         split_filename(filename_copy, &dirname, &basename);
1299
1300         if (!strcmp(dirname, "/") && !strcmp(basename, "")) {
1301                 printf("Error: cannot remove root\n");
1302                 ret = -EINVAL;
1303                 goto exit;
1304         }
1305
1306         itr = malloc_cache_aligned(sizeof(fat_itr));
1307         if (!itr) {
1308                 printf("Error: allocating memory\n");
1309                 ret = -ENOMEM;
1310                 goto exit;
1311         }
1312
1313         ret = fat_itr_root(itr, &fsdata);
1314         if (ret)
1315                 goto exit;
1316
1317         total_sector = fsdata.total_sect;
1318
1319         ret = fat_itr_resolve(itr, dirname, TYPE_DIR);
1320         if (ret) {
1321                 printf("%s: doesn't exist (%d)\n", dirname, ret);
1322                 ret = -ENOENT;
1323                 goto exit;
1324         }
1325
1326         if (!find_directory_entry(itr, basename)) {
1327                 printf("%s: doesn't exist\n", basename);
1328                 ret = -ENOENT;
1329                 goto exit;
1330         }
1331
1332         if (fat_itr_isdir(itr)) {
1333                 n_entries = fat_dir_entries(itr);
1334                 if (n_entries < 0) {
1335                         ret = n_entries;
1336                         goto exit;
1337                 }
1338                 if (n_entries > 2) {
1339                         printf("Error: directory is not empty: %d\n",
1340                                n_entries);
1341                         ret = -EINVAL;
1342                         goto exit;
1343                 }
1344         }
1345
1346         ret = delete_dentry(itr);
1347
1348 exit:
1349         free(fsdata.fatbuf);
1350         free(itr);
1351         free(filename_copy);
1352
1353         return ret;
1354 }
1355
1356 int fat_mkdir(const char *new_dirname)
1357 {
1358         dir_entry *retdent;
1359         fsdata datablock = { .fatbuf = NULL, };
1360         fsdata *mydata = &datablock;
1361         fat_itr *itr = NULL;
1362         char *dirname_copy, *parent, *dirname;
1363         char l_dirname[VFAT_MAXLEN_BYTES];
1364         int ret = -1;
1365         loff_t actwrite;
1366         unsigned int bytesperclust;
1367         dir_entry *dotdent = NULL;
1368
1369         dirname_copy = strdup(new_dirname);
1370         if (!dirname_copy)
1371                 goto exit;
1372
1373         split_filename(dirname_copy, &parent, &dirname);
1374         if (!strlen(dirname)) {
1375                 ret = -EINVAL;
1376                 goto exit;
1377         }
1378
1379         if (normalize_longname(l_dirname, dirname)) {
1380                 printf("FAT: illegal filename (%s)\n", dirname);
1381                 ret = -EINVAL;
1382                 goto exit;
1383         }
1384
1385         itr = malloc_cache_aligned(sizeof(fat_itr));
1386         if (!itr) {
1387                 ret = -ENOMEM;
1388                 goto exit;
1389         }
1390
1391         ret = fat_itr_root(itr, &datablock);
1392         if (ret)
1393                 goto exit;
1394
1395         total_sector = datablock.total_sect;
1396
1397         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1398         if (ret) {
1399                 printf("%s: doesn't exist (%d)\n", parent, ret);
1400                 goto exit;
1401         }
1402
1403         retdent = find_directory_entry(itr, l_dirname);
1404
1405         if (retdent) {
1406                 printf("%s: already exists\n", l_dirname);
1407                 ret = -EEXIST;
1408                 goto exit;
1409         } else {
1410                 if (itr->is_root) {
1411                         /* root dir cannot have "." or ".." */
1412                         if (!strcmp(l_dirname, ".") ||
1413                             !strcmp(l_dirname, "..")) {
1414                                 ret = -EINVAL;
1415                                 goto exit;
1416                         }
1417                 }
1418
1419                 if (!itr->dent) {
1420                         printf("Error: allocating new dir entry\n");
1421                         ret = -EIO;
1422                         goto exit;
1423                 }
1424
1425                 memset(itr->dent, 0, sizeof(*itr->dent));
1426
1427                 /* Set short name to set alias checksum field in dir_slot */
1428                 set_name(itr->dent, dirname);
1429                 fill_dir_slot(itr, dirname);
1430
1431                 /* Set attribute as archive for regular file */
1432                 fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0,
1433                             ATTR_DIR | ATTR_ARCH);
1434
1435                 retdent = itr->dent;
1436         }
1437
1438         /* Default entries */
1439         bytesperclust = mydata->clust_size * mydata->sect_size;
1440         dotdent = malloc_cache_aligned(bytesperclust);
1441         if (!dotdent) {
1442                 ret = -ENOMEM;
1443                 goto exit;
1444         }
1445         memset(dotdent, 0, bytesperclust);
1446
1447         memcpy(dotdent[0].name, ".       ", 8);
1448         memcpy(dotdent[0].ext, "   ", 3);
1449         dotdent[0].attr = ATTR_DIR | ATTR_ARCH;
1450
1451         memcpy(dotdent[1].name, "..      ", 8);
1452         memcpy(dotdent[1].ext, "   ", 3);
1453         dotdent[1].attr = ATTR_DIR | ATTR_ARCH;
1454         set_start_cluster(mydata, &dotdent[1], itr->start_clust);
1455
1456         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1457                            bytesperclust, &actwrite);
1458         if (ret < 0) {
1459                 printf("Error: writing contents\n");
1460                 goto exit;
1461         }
1462         /* Write twice for "." */
1463         set_start_cluster(mydata, &dotdent[0], START(retdent));
1464         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1465                            bytesperclust, &actwrite);
1466         if (ret < 0) {
1467                 printf("Error: writing contents\n");
1468                 goto exit;
1469         }
1470
1471         /* Flush fat buffer */
1472         ret = flush_dirty_fat_buffer(mydata);
1473         if (ret) {
1474                 printf("Error: flush fat buffer\n");
1475                 goto exit;
1476         }
1477
1478         /* Write directory table to device */
1479         ret = flush_dir(itr);
1480         if (ret)
1481                 printf("Error: writing directory entry\n");
1482
1483 exit:
1484         free(dirname_copy);
1485         free(mydata->fatbuf);
1486         free(itr);
1487         free(dotdent);
1488         return ret;
1489 }