fs/fat/fat_write.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * fat_write.c
   4  *
   5  * R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
   6  */
   7
   8 #include <common.h>
   9 #include <command.h>
  10 #include <config.h>
  11 #include <fat.h>
  12 #include <malloc.h>
  13 #include <asm/byteorder.h>
  14 #include <part.h>
  15 #include <asm/cache.h>
  16 #include <linux/ctype.h>
  17 #include <div64.h>
  18 #include <linux/math64.h>
  19 #include "fat.c"
  20
  21 static void uppercase(char *str, int len)
  22 {
  23         int i;
  24
  25         for (i = 0; i < len; i++) {
  26                 *str = toupper(*str);
  27                 str++;
  28         }
  29 }
  30
  31 static int total_sector;
  32 static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
  33 {
  34         ulong ret;
  35
  36         if (!cur_dev)
  37                 return -1;
  38
  39         if (cur_part_info.start + block + nr_blocks >
  40                 cur_part_info.start + total_sector) {
  41                 printf("error: overflow occurs\n");
  42                 return -1;
  43         }
  44
  45         ret = blk_dwrite(cur_dev, cur_part_info.start + block, nr_blocks, buf);
  46         if (nr_blocks && ret == 0)
  47                 return -1;
  48
  49         return ret;
  50 }
  51
  52 /*
  53  * Set short name in directory entry
  54  */
  55 static void set_name(dir_entry *dirent, const char *filename)
  56 {
  57         char s_name[VFAT_MAXLEN_BYTES];
  58         char *period;
  59         int period_location, len, i, ext_num;
  60
  61         if (filename == NULL)
  62                 return;
  63
  64         len = strlen(filename);
  65         if (len == 0)
  66                 return;
  67
  68         strcpy(s_name, filename);
  69         uppercase(s_name, len);
  70
  71         period = strchr(s_name, '.');
  72         if (period == NULL) {
  73                 period_location = len;
  74                 ext_num = 0;
  75         } else {
  76                 period_location = period - s_name;
  77                 ext_num = len - period_location - 1;
  78         }
  79
  80         /* Pad spaces when the length of file name is shorter than eight */
  81         if (period_location < 8) {
  82                 memcpy(dirent->name, s_name, period_location);
  83                 for (i = period_location; i < 8; i++)
  84                         dirent->name[i] = ' ';
  85         } else if (period_location == 8) {
  86                 memcpy(dirent->name, s_name, period_location);
  87         } else {
  88                 memcpy(dirent->name, s_name, 6);
  89                 dirent->name[6] = '~';
  90                 dirent->name[7] = '1';
  91         }
  92
  93         if (ext_num < 3) {
  94                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
  95                 for (i = ext_num; i < 3; i++)
  96                         dirent->ext[i] = ' ';
  97         } else
  98                 memcpy(dirent->ext, s_name + period_location + 1, 3);
  99
 100         debug("name : %s\n", dirent->name);
 101         debug("ext : %s\n", dirent->ext);
 102 }
 103
 104 /*
 105  * Write fat buffer into block device
 106  */
 107 static int flush_dirty_fat_buffer(fsdata *mydata)
 108 {
 109         int getsize = FATBUFBLOCKS;
 110         __u32 fatlength = mydata->fatlength;
 111         __u8 *bufptr = mydata->fatbuf;
 112         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 113
 114         debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum,
 115               (int)mydata->fat_dirty);
 116
 117         if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1))
 118                 return 0;
 119
 120         /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 121         if (startblock + getsize > fatlength)
 122                 getsize = fatlength - startblock;
 123
 124         startblock += mydata->fat_sect;
 125
 126         /* Write FAT buf */
 127         if (disk_write(startblock, getsize, bufptr) < 0) {
 128                 debug("error: writing FAT blocks\n");
 129                 return -1;
 130         }
 131
 132         if (mydata->fats == 2) {
 133                 /* Update corresponding second FAT blocks */
 134                 startblock += mydata->fatlength;
 135                 if (disk_write(startblock, getsize, bufptr) < 0) {
 136                         debug("error: writing second FAT blocks\n");
 137                         return -1;
 138                 }
 139         }
 140         mydata->fat_dirty = 0;
 141
 142         return 0;
 143 }
 144
 145 /*
 146  * Set the file name information from 'name' into 'slotptr',
 147  */
 148 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 149 {
 150         int j, end_idx = 0;
 151
 152         for (j = 0; j <= 8; j += 2) {
 153                 if (name[*idx] == 0x00) {
 154                         slotptr->name0_4[j] = 0;
 155                         slotptr->name0_4[j + 1] = 0;
 156                         end_idx++;
 157                         goto name0_4;
 158                 }
 159                 slotptr->name0_4[j] = name[*idx];
 160                 (*idx)++;
 161                 end_idx++;
 162         }
 163         for (j = 0; j <= 10; j += 2) {
 164                 if (name[*idx] == 0x00) {
 165                         slotptr->name5_10[j] = 0;
 166                         slotptr->name5_10[j + 1] = 0;
 167                         end_idx++;
 168                         goto name5_10;
 169                 }
 170                 slotptr->name5_10[j] = name[*idx];
 171                 (*idx)++;
 172                 end_idx++;
 173         }
 174         for (j = 0; j <= 2; j += 2) {
 175                 if (name[*idx] == 0x00) {
 176                         slotptr->name11_12[j] = 0;
 177                         slotptr->name11_12[j + 1] = 0;
 178                         end_idx++;
 179                         goto name11_12;
 180                 }
 181                 slotptr->name11_12[j] = name[*idx];
 182                 (*idx)++;
 183                 end_idx++;
 184         }
 185
 186         if (name[*idx] == 0x00)
 187                 return 1;
 188
 189         return 0;
 190 /* Not used characters are filled with 0xff 0xff */
 191 name0_4:
 192         for (; end_idx < 5; end_idx++) {
 193                 slotptr->name0_4[end_idx * 2] = 0xff;
 194                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 195         }
 196         end_idx = 5;
 197 name5_10:
 198         end_idx -= 5;
 199         for (; end_idx < 6; end_idx++) {
 200                 slotptr->name5_10[end_idx * 2] = 0xff;
 201                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 202         }
 203         end_idx = 11;
 204 name11_12:
 205         end_idx -= 11;
 206         for (; end_idx < 2; end_idx++) {
 207                 slotptr->name11_12[end_idx * 2] = 0xff;
 208                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 209         }
 210
 211         return 1;
 212 }
 213
 214 static int new_dir_table(fat_itr *itr);
 215 static int flush_dir(fat_itr *itr);
 216
 217 /*
 218  * Fill dir_slot entries with appropriate name, id, and attr
 219  * 'itr' will point to a next entry
 220  */
 221 static int
 222 fill_dir_slot(fat_itr *itr, const char *l_name)
 223 {
 224         __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
 225         dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
 226         __u8 counter = 0, checksum;
 227         int idx = 0, ret;
 228
 229         /* Get short file name checksum value */
 230         checksum = mkcksum(itr->dent->name, itr->dent->ext);
 231
 232         do {
 233                 memset(slotptr, 0x00, sizeof(dir_slot));
 234                 ret = str2slot(slotptr, l_name, &idx);
 235                 slotptr->id = ++counter;
 236                 slotptr->attr = ATTR_VFAT;
 237                 slotptr->alias_checksum = checksum;
 238                 slotptr++;
 239         } while (ret == 0);
 240
 241         slotptr--;
 242         slotptr->id |= LAST_LONG_ENTRY_MASK;
 243
 244         while (counter >= 1) {
 245                 memcpy(itr->dent, slotptr, sizeof(dir_slot));
 246                 slotptr--;
 247                 counter--;
 248
 249                 if (itr->remaining == 0)
 250                         flush_dir(itr);
 251
 252                 /* allocate a cluster for more entries */
 253                 if (!fat_itr_next(itr))
 254                         if (!itr->dent &&
 255                             (!itr->is_root || itr->fsdata->fatsize == 32) &&
 256                             new_dir_table(itr))
 257                                 return -1;
 258         }
 259
 260         return 0;
 261 }
 262
 263 /*
 264  * Set the entry at index 'entry' in a FAT (12/16/32) table.
 265  */
 266 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 267 {
 268         __u32 bufnum, offset, off16;
 269         __u16 val1, val2;
 270
 271         switch (mydata->fatsize) {
 272         case 32:
 273                 bufnum = entry / FAT32BUFSIZE;
 274                 offset = entry - bufnum * FAT32BUFSIZE;
 275                 break;
 276         case 16:
 277                 bufnum = entry / FAT16BUFSIZE;
 278                 offset = entry - bufnum * FAT16BUFSIZE;
 279                 break;
 280         case 12:
 281                 bufnum = entry / FAT12BUFSIZE;
 282                 offset = entry - bufnum * FAT12BUFSIZE;
 283                 break;
 284         default:
 285                 /* Unsupported FAT size */
 286                 return -1;
 287         }
 288
 289         /* Read a new block of FAT entries into the cache. */
 290         if (bufnum != mydata->fatbufnum) {
 291                 int getsize = FATBUFBLOCKS;
 292                 __u8 *bufptr = mydata->fatbuf;
 293                 __u32 fatlength = mydata->fatlength;
 294                 __u32 startblock = bufnum * FATBUFBLOCKS;
 295
 296                 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 297                 if (startblock + getsize > fatlength)
 298                         getsize = fatlength - startblock;
 299
 300                 if (flush_dirty_fat_buffer(mydata) < 0)
 301                         return -1;
 302
 303                 startblock += mydata->fat_sect;
 304
 305                 if (disk_read(startblock, getsize, bufptr) < 0) {
 306                         debug("Error reading FAT blocks\n");
 307                         return -1;
 308                 }
 309                 mydata->fatbufnum = bufnum;
 310         }
 311
 312         /* Mark as dirty */
 313         mydata->fat_dirty = 1;
 314
 315         /* Set the actual entry */
 316         switch (mydata->fatsize) {
 317         case 32:
 318                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 319                 break;
 320         case 16:
 321                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 322                 break;
 323         case 12:
 324                 off16 = (offset * 3) / 4;
 325
 326                 switch (offset & 0x3) {
 327                 case 0:
 328                         val1 = cpu_to_le16(entry_value) & 0xfff;
 329                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
 330                         ((__u16 *)mydata->fatbuf)[off16] |= val1;
 331                         break;
 332                 case 1:
 333                         val1 = cpu_to_le16(entry_value) & 0xf;
 334                         val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
 335
 336                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
 337                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
 338
 339                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
 340                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 341                         break;
 342                 case 2:
 343                         val1 = cpu_to_le16(entry_value) & 0xff;
 344                         val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
 345
 346                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
 347                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
 348
 349                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
 350                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 351                         break;
 352                 case 3:
 353                         val1 = cpu_to_le16(entry_value) & 0xfff;
 354                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
 355                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
 356                         break;
 357                 default:
 358                         break;
 359                 }
 360
 361                 break;
 362         default:
 363                 return -1;
 364         }
 365
 366         return 0;
 367 }
 368
 369 /*
 370  * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
 371  * and link it to 'entry'. EOC marker is not set on returned entry.
 372  */
 373 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 374 {
 375         __u32 next_fat, next_entry = entry + 1;
 376
 377         while (1) {
 378                 next_fat = get_fatent(mydata, next_entry);
 379                 if (next_fat == 0) {
 380                         /* found free entry, link to entry */
 381                         set_fatent_value(mydata, entry, next_entry);
 382                         break;
 383                 }
 384                 next_entry++;
 385         }
 386         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 387                mydata->fatsize, entry, next_entry);
 388
 389         return next_entry;
 390 }
 391
 392 /**
 393  * set_sectors() - write data to sectors
 394  *
 395  * Write 'size' bytes from 'buffer' into the specified sector.
 396  *
 397  * @mydata:     data to be written
 398  * @startsect:  sector to be written to
 399  * @buffer:     data to be written
 400  * @size:       bytes to be written (but not more than the size of a cluster)
 401  * Return:      0 on success, -1 otherwise
 402  */
 403 static int
 404 set_sectors(fsdata *mydata, u32 startsect, u8 *buffer, u32 size)
 405 {
 406         u32 nsects = 0;
 407         int ret;
 408
 409         debug("startsect: %d\n", startsect);
 410
 411         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 412                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 413
 414                 debug("FAT: Misaligned buffer address (%p)\n", buffer);
 415
 416                 while (size >= mydata->sect_size) {
 417                         memcpy(tmpbuf, buffer, mydata->sect_size);
 418                         ret = disk_write(startsect++, 1, tmpbuf);
 419                         if (ret != 1) {
 420                                 debug("Error writing data (got %d)\n", ret);
 421                                 return -1;
 422                         }
 423
 424                         buffer += mydata->sect_size;
 425                         size -= mydata->sect_size;
 426                 }
 427         } else if (size >= mydata->sect_size) {
 428                 nsects = size / mydata->sect_size;
 429                 ret = disk_write(startsect, nsects, buffer);
 430                 if (ret != nsects) {
 431                         debug("Error writing data (got %d)\n", ret);
 432                         return -1;
 433                 }
 434
 435                 startsect += nsects;
 436                 buffer += nsects * mydata->sect_size;
 437                 size -= nsects * mydata->sect_size;
 438         }
 439
 440         if (size) {
 441                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 442                 /* Do not leak content of stack */
 443                 memset(tmpbuf, 0, mydata->sect_size);
 444                 memcpy(tmpbuf, buffer, size);
 445                 ret = disk_write(startsect, 1, tmpbuf);
 446                 if (ret != 1) {
 447                         debug("Error writing data (got %d)\n", ret);
 448                         return -1;
 449                 }
 450         }
 451
 452         return 0;
 453 }
 454
 455 /**
 456  * set_cluster() - write data to cluster
 457  *
 458  * Write 'size' bytes from 'buffer' into the specified cluster.
 459  *
 460  * @mydata:     data to be written
 461  * @clustnum:   cluster to be written to
 462  * @buffer:     data to be written
 463  * @size:       bytes to be written (but not more than the size of a cluster)
 464  * Return:      0 on success, -1 otherwise
 465  */
 466 static int
 467 set_cluster(fsdata *mydata, u32 clustnum, u8 *buffer, u32 size)
 468 {
 469         return set_sectors(mydata, clust_to_sect(mydata, clustnum),
 470                            buffer, size);
 471 }
 472
 473 static int
 474 flush_dir(fat_itr *itr)
 475 {
 476         fsdata *mydata = itr->fsdata;
 477         u32 startsect, sect_offset, nsects;
 478
 479         if (!itr->is_root || mydata->fatsize == 32)
 480                 return set_cluster(mydata, itr->clust, itr->block,
 481                                    mydata->clust_size * mydata->sect_size);
 482
 483         sect_offset = itr->clust * mydata->clust_size;
 484         startsect = mydata->rootdir_sect + sect_offset;
 485         /* do not write past the end of rootdir */
 486         nsects = min_t(u32, mydata->clust_size,
 487                        mydata->rootdir_size - sect_offset);
 488
 489         return set_sectors(mydata, startsect, itr->block,
 490                            nsects * mydata->sect_size);
 491 }
 492
 493 static __u8 tmpbuf_cluster[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
 494
 495 /*
 496  * Read and modify data on existing and consecutive cluster blocks
 497  */
 498 static int
 499 get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
 500                 loff_t size, loff_t *gotsize)
 501 {
 502         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 503         __u32 startsect;
 504         loff_t wsize;
 505         int clustcount, i, ret;
 506
 507         *gotsize = 0;
 508         if (!size)
 509                 return 0;
 510
 511         assert(pos < bytesperclust);
 512         startsect = clust_to_sect(mydata, clustnum);
 513
 514         debug("clustnum: %d, startsect: %d, pos: %lld\n",
 515               clustnum, startsect, pos);
 516
 517         /* partial write at beginning */
 518         if (pos) {
 519                 wsize = min(bytesperclust - pos, size);
 520                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 521                 if (ret != mydata->clust_size) {
 522                         debug("Error reading data (got %d)\n", ret);
 523                         return -1;
 524                 }
 525
 526                 memcpy(tmpbuf_cluster + pos, buffer, wsize);
 527                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 528                 if (ret != mydata->clust_size) {
 529                         debug("Error writing data (got %d)\n", ret);
 530                         return -1;
 531                 }
 532
 533                 size -= wsize;
 534                 buffer += wsize;
 535                 *gotsize += wsize;
 536
 537                 startsect += mydata->clust_size;
 538
 539                 if (!size)
 540                         return 0;
 541         }
 542
 543         /* full-cluster write */
 544         if (size >= bytesperclust) {
 545                 clustcount = lldiv(size, bytesperclust);
 546
 547                 if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
 548                         wsize = clustcount * bytesperclust;
 549                         ret = disk_write(startsect,
 550                                          clustcount * mydata->clust_size,
 551                                          buffer);
 552                         if (ret != clustcount * mydata->clust_size) {
 553                                 debug("Error writing data (got %d)\n", ret);
 554                                 return -1;
 555                         }
 556
 557                         size -= wsize;
 558                         buffer += wsize;
 559                         *gotsize += wsize;
 560
 561                         startsect += clustcount * mydata->clust_size;
 562                 } else {
 563                         for (i = 0; i < clustcount; i++) {
 564                                 memcpy(tmpbuf_cluster, buffer, bytesperclust);
 565                                 ret = disk_write(startsect,
 566                                                  mydata->clust_size,
 567                                                  tmpbuf_cluster);
 568                                 if (ret != mydata->clust_size) {
 569                                         debug("Error writing data (got %d)\n",
 570                                               ret);
 571                                         return -1;
 572                                 }
 573
 574                                 size -= bytesperclust;
 575                                 buffer += bytesperclust;
 576                                 *gotsize += bytesperclust;
 577
 578                                 startsect += mydata->clust_size;
 579                         }
 580                 }
 581         }
 582
 583         /* partial write at end */
 584         if (size) {
 585                 wsize = size;
 586                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 587                 if (ret != mydata->clust_size) {
 588                         debug("Error reading data (got %d)\n", ret);
 589                         return -1;
 590                 }
 591                 memcpy(tmpbuf_cluster, buffer, wsize);
 592                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 593                 if (ret != mydata->clust_size) {
 594                         debug("Error writing data (got %d)\n", ret);
 595                         return -1;
 596                 }
 597
 598                 size -= wsize;
 599                 buffer += wsize;
 600                 *gotsize += wsize;
 601         }
 602
 603         assert(!size);
 604
 605         return 0;
 606 }
 607
 608 /*
 609  * Find the first empty cluster
 610  */
 611 static int find_empty_cluster(fsdata *mydata)
 612 {
 613         __u32 fat_val, entry = 3;
 614
 615         while (1) {
 616                 fat_val = get_fatent(mydata, entry);
 617                 if (fat_val == 0)
 618                         break;
 619                 entry++;
 620         }
 621
 622         return entry;
 623 }
 624
 625 /*
 626  * Allocate a cluster for additional directory entries
 627  */
 628 static int new_dir_table(fat_itr *itr)
 629 {
 630         fsdata *mydata = itr->fsdata;
 631         int dir_newclust = 0;
 632         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 633
 634         dir_newclust = find_empty_cluster(mydata);
 635         set_fatent_value(mydata, itr->clust, dir_newclust);
 636         if (mydata->fatsize == 32)
 637                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 638         else if (mydata->fatsize == 16)
 639                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 640         else if (mydata->fatsize == 12)
 641                 set_fatent_value(mydata, dir_newclust, 0xff8);
 642
 643         itr->clust = dir_newclust;
 644         itr->next_clust = dir_newclust;
 645
 646         if (flush_dirty_fat_buffer(mydata) < 0)
 647                 return -1;
 648
 649         memset(itr->block, 0x00, bytesperclust);
 650
 651         itr->dent = (dir_entry *)itr->block;
 652         itr->last_cluster = 1;
 653         itr->remaining = bytesperclust / sizeof(dir_entry) - 1;
 654
 655         return 0;
 656 }
 657
 658 /*
 659  * Set empty cluster from 'entry' to the end of a file
 660  */
 661 static int clear_fatent(fsdata *mydata, __u32 entry)
 662 {
 663         __u32 fat_val;
 664
 665         while (!CHECK_CLUST(entry, mydata->fatsize)) {
 666                 fat_val = get_fatent(mydata, entry);
 667                 if (fat_val != 0)
 668                         set_fatent_value(mydata, entry, 0);
 669                 else
 670                         break;
 671
 672                 entry = fat_val;
 673         }
 674
 675         /* Flush fat buffer */
 676         if (flush_dirty_fat_buffer(mydata) < 0)
 677                 return -1;
 678
 679         return 0;
 680 }
 681
 682 /*
 683  * Set start cluster in directory entry
 684  */
 685 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 686                               __u32 start_cluster)
 687 {
 688         if (mydata->fatsize == 32)
 689                 dentptr->starthi =
 690                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 691         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 692 }
 693
 694 /*
 695  * Check whether adding a file makes the file system to
 696  * exceed the size of the block device
 697  * Return -1 when overflow occurs, otherwise return 0
 698  */
 699 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 700 {
 701         __u32 startsect, sect_num, offset;
 702
 703         if (clustnum > 0)
 704                 startsect = clust_to_sect(mydata, clustnum);
 705         else
 706                 startsect = mydata->rootdir_sect;
 707
 708         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 709
 710         if (offset != 0)
 711                 sect_num++;
 712
 713         if (startsect + sect_num > total_sector)
 714                 return -1;
 715         return 0;
 716 }
 717
 718 /*
 719  * Write at most 'maxsize' bytes from 'buffer' into
 720  * the file associated with 'dentptr'
 721  * Update the number of bytes written in *gotsize and return 0
 722  * or return -1 on fatal errors.
 723  */
 724 static int
 725 set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
 726              loff_t maxsize, loff_t *gotsize)
 727 {
 728         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 729         __u32 curclust = START(dentptr);
 730         __u32 endclust = 0, newclust = 0;
 731         u64 cur_pos, filesize;
 732         loff_t offset, actsize, wsize;
 733
 734         *gotsize = 0;
 735         filesize = pos + maxsize;
 736
 737         debug("%llu bytes\n", filesize);
 738
 739         if (!filesize) {
 740                 if (!curclust)
 741                         return 0;
 742                 if (!CHECK_CLUST(curclust, mydata->fatsize) ||
 743                     IS_LAST_CLUST(curclust, mydata->fatsize)) {
 744                         clear_fatent(mydata, curclust);
 745                         set_start_cluster(mydata, dentptr, 0);
 746                         return 0;
 747                 }
 748                 debug("curclust: 0x%x\n", curclust);
 749                 debug("Invalid FAT entry\n");
 750                 return -1;
 751         }
 752
 753         if (!curclust) {
 754                 assert(pos == 0);
 755                 goto set_clusters;
 756         }
 757
 758         /* go to cluster at pos */
 759         cur_pos = bytesperclust;
 760         while (1) {
 761                 if (pos <= cur_pos)
 762                         break;
 763                 if (IS_LAST_CLUST(curclust, mydata->fatsize))
 764                         break;
 765
 766                 newclust = get_fatent(mydata, curclust);
 767                 if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
 768                     CHECK_CLUST(newclust, mydata->fatsize)) {
 769                         debug("curclust: 0x%x\n", curclust);
 770                         debug("Invalid FAT entry\n");
 771                         return -1;
 772                 }
 773
 774                 cur_pos += bytesperclust;
 775                 curclust = newclust;
 776         }
 777         if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 778                 assert(pos == cur_pos);
 779                 goto set_clusters;
 780         }
 781
 782         assert(pos < cur_pos);
 783         cur_pos -= bytesperclust;
 784
 785         /* overwrite */
 786         assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
 787                !CHECK_CLUST(curclust, mydata->fatsize));
 788
 789         while (1) {
 790                 /* search for allocated consecutive clusters */
 791                 actsize = bytesperclust;
 792                 endclust = curclust;
 793                 while (1) {
 794                         if (filesize <= (cur_pos + actsize))
 795                                 break;
 796
 797                         newclust = get_fatent(mydata, endclust);
 798
 799                         if (newclust != endclust + 1)
 800                                 break;
 801                         if (IS_LAST_CLUST(newclust, mydata->fatsize))
 802                                 break;
 803                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 804                                 debug("curclust: 0x%x\n", curclust);
 805                                 debug("Invalid FAT entry\n");
 806                                 return -1;
 807                         }
 808
 809                         actsize += bytesperclust;
 810                         endclust = newclust;
 811                 }
 812
 813                 /* overwrite to <curclust..endclust> */
 814                 if (pos < cur_pos)
 815                         offset = 0;
 816                 else
 817                         offset = pos - cur_pos;
 818                 wsize = min_t(unsigned long long, actsize, filesize - cur_pos);
 819                 wsize -= offset;
 820
 821                 if (get_set_cluster(mydata, curclust, offset,
 822                                     buffer, wsize, &actsize)) {
 823                         printf("Error get-and-setting cluster\n");
 824                         return -1;
 825                 }
 826                 buffer += wsize;
 827                 *gotsize += wsize;
 828                 cur_pos += offset + wsize;
 829
 830                 if (filesize <= cur_pos)
 831                         break;
 832
 833                 if (IS_LAST_CLUST(newclust, mydata->fatsize))
 834                         /* no more clusters */
 835                         break;
 836
 837                 curclust = newclust;
 838         }
 839
 840         if (filesize <= cur_pos) {
 841                 /* no more write */
 842                 newclust = get_fatent(mydata, endclust);
 843                 if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
 844                         /* truncate the rest */
 845                         clear_fatent(mydata, newclust);
 846
 847                         /* Mark end of file in FAT */
 848                         if (mydata->fatsize == 12)
 849                                 newclust = 0xfff;
 850                         else if (mydata->fatsize == 16)
 851                                 newclust = 0xffff;
 852                         else if (mydata->fatsize == 32)
 853                                 newclust = 0xfffffff;
 854                         set_fatent_value(mydata, endclust, newclust);
 855                 }
 856
 857                 return 0;
 858         }
 859
 860         curclust = endclust;
 861         filesize -= cur_pos;
 862         assert(!do_div(cur_pos, bytesperclust));
 863
 864 set_clusters:
 865         /* allocate and write */
 866         assert(!pos);
 867
 868         /* Assure that curclust is valid */
 869         if (!curclust) {
 870                 curclust = find_empty_cluster(mydata);
 871                 set_start_cluster(mydata, dentptr, curclust);
 872         } else {
 873                 newclust = get_fatent(mydata, curclust);
 874
 875                 if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
 876                         newclust = determine_fatent(mydata, curclust);
 877                         set_fatent_value(mydata, curclust, newclust);
 878                         curclust = newclust;
 879                 } else {
 880                         debug("error: something wrong\n");
 881                         return -1;
 882                 }
 883         }
 884
 885         /* TODO: already partially written */
 886         if (check_overflow(mydata, curclust, filesize)) {
 887                 printf("Error: no space left: %llu\n", filesize);
 888                 return -1;
 889         }
 890
 891         actsize = bytesperclust;
 892         endclust = curclust;
 893         do {
 894                 /* search for consecutive clusters */
 895                 while (actsize < filesize) {
 896                         newclust = determine_fatent(mydata, endclust);
 897
 898                         if ((newclust - 1) != endclust)
 899                                 /* write to <curclust..endclust> */
 900                                 goto getit;
 901
 902                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 903                                 debug("newclust: 0x%x\n", newclust);
 904                                 debug("Invalid FAT entry\n");
 905                                 return 0;
 906                         }
 907                         endclust = newclust;
 908                         actsize += bytesperclust;
 909                 }
 910
 911                 /* set remaining bytes */
 912                 actsize = filesize;
 913                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 914                         debug("error: writing cluster\n");
 915                         return -1;
 916                 }
 917                 *gotsize += actsize;
 918
 919                 /* Mark end of file in FAT */
 920                 if (mydata->fatsize == 12)
 921                         newclust = 0xfff;
 922                 else if (mydata->fatsize == 16)
 923                         newclust = 0xffff;
 924                 else if (mydata->fatsize == 32)
 925                         newclust = 0xfffffff;
 926                 set_fatent_value(mydata, endclust, newclust);
 927
 928                 return 0;
 929 getit:
 930                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 931                         debug("error: writing cluster\n");
 932                         return -1;
 933                 }
 934                 *gotsize += actsize;
 935                 filesize -= actsize;
 936                 buffer += actsize;
 937
 938                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 939                         debug("newclust: 0x%x\n", newclust);
 940                         debug("Invalid FAT entry\n");
 941                         return 0;
 942                 }
 943                 actsize = bytesperclust;
 944                 curclust = endclust = newclust;
 945         } while (1);
 946
 947         return 0;
 948 }
 949
 950 /*
 951  * Fill dir_entry
 952  */
 953 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 954         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 955 {
 956         set_start_cluster(mydata, dentptr, start_cluster);
 957         dentptr->size = cpu_to_le32(size);
 958
 959         dentptr->attr = attr;
 960
 961         set_name(dentptr, filename);
 962 }
 963
 964 /*
 965  * Find a directory entry based on filename or start cluster number
 966  * If the directory entry is not found,
 967  * the new position for writing a directory entry will be returned
 968  */
 969 static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
 970 {
 971         int match = 0;
 972
 973         while (fat_itr_next(itr)) {
 974                 /* check both long and short name: */
 975                 if (!strcasecmp(filename, itr->name))
 976                         match = 1;
 977                 else if (itr->name != itr->s_name &&
 978                          !strcasecmp(filename, itr->s_name))
 979                         match = 1;
 980
 981                 if (!match)
 982                         continue;
 983
 984                 if (itr->dent->name[0] == '\0')
 985                         return NULL;
 986                 else
 987                         return itr->dent;
 988         }
 989
 990         /* allocate a cluster for more entries */
 991         if (!itr->dent &&
 992             (!itr->is_root || itr->fsdata->fatsize == 32) &&
 993             new_dir_table(itr))
 994                 /* indicate that allocating dent failed */
 995                 itr->dent = NULL;
 996
 997         return NULL;
 998 }
 999
1000 static int split_filename(char *filename, char **dirname, char **basename)
1001 {
1002         char *p, *last_slash, *last_slash_cont;
1003
1004 again:
1005         p = filename;
1006         last_slash = NULL;
1007         last_slash_cont = NULL;
1008         while (*p) {
1009                 if (ISDIRDELIM(*p)) {
1010                         last_slash = p;
1011                         last_slash_cont = p;
1012                         /* continuous slashes */
1013                         while (ISDIRDELIM(*p))
1014                                 last_slash_cont = p++;
1015                         if (!*p)
1016                                 break;
1017                 }
1018                 p++;
1019         }
1020
1021         if (last_slash) {
1022                 if (last_slash_cont == (filename + strlen(filename) - 1)) {
1023                         /* remove trailing slashes */
1024                         *last_slash = '\0';
1025                         goto again;
1026                 }
1027
1028                 if (last_slash == filename) {
1029                         /* avoid ""(null) directory */
1030                         *dirname = "/";
1031                 } else {
1032                         *last_slash = '\0';
1033                         *dirname = filename;
1034                 }
1035
1036                 *last_slash_cont = '\0';
1037                 *basename = last_slash_cont + 1;
1038         } else {
1039                 *dirname = "/"; /* root by default */
1040                 *basename = filename;
1041         }
1042
1043         return 0;
1044 }
1045
1046 /**
1047  * normalize_longname() - check long file name and convert to lower case
1048  *
1049  * We assume here that the FAT file system is using an 8bit code page.
1050  * Linux typically uses CP437, EDK2 assumes CP1250.
1051  *
1052  * @l_filename: preallocated buffer receiving the normalized name
1053  * @filename:   filename to normalize
1054  * Return:      0 on success, -1 on failure
1055  */
1056 static int normalize_longname(char *l_filename, const char *filename)
1057 {
1058         const char *p, illegal[] = "<>:\"/\\|?*";
1059
1060         if (strlen(filename) >= VFAT_MAXLEN_BYTES)
1061                 return -1;
1062
1063         for (p = filename; *p; ++p) {
1064                 if ((unsigned char)*p < 0x20)
1065                         return -1;
1066                 if (strchr(illegal, *p))
1067                         return -1;
1068         }
1069
1070         strcpy(l_filename, filename);
1071         downcase(l_filename, VFAT_MAXLEN_BYTES);
1072
1073         return 0;
1074 }
1075
1076 int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
1077                       loff_t size, loff_t *actwrite)
1078 {
1079         dir_entry *retdent;
1080         fsdata datablock = { .fatbuf = NULL, };
1081         fsdata *mydata = &datablock;
1082         fat_itr *itr = NULL;
1083         int ret = -1;
1084         char *filename_copy, *parent, *basename;
1085         char l_filename[VFAT_MAXLEN_BYTES];
1086
1087         debug("writing %s\n", filename);
1088
1089         filename_copy = strdup(filename);
1090         if (!filename_copy)
1091                 return -ENOMEM;
1092
1093         split_filename(filename_copy, &parent, &basename);
1094         if (!strlen(basename)) {
1095                 ret = -EINVAL;
1096                 goto exit;
1097         }
1098
1099         filename = basename;
1100         if (normalize_longname(l_filename, filename)) {
1101                 printf("FAT: illegal filename (%s)\n", filename);
1102                 ret = -EINVAL;
1103                 goto exit;
1104         }
1105
1106         itr = malloc_cache_aligned(sizeof(fat_itr));
1107         if (!itr) {
1108                 ret = -ENOMEM;
1109                 goto exit;
1110         }
1111
1112         ret = fat_itr_root(itr, &datablock);
1113         if (ret)
1114                 goto exit;
1115
1116         total_sector = datablock.total_sect;
1117
1118         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1119         if (ret) {
1120                 printf("%s: doesn't exist (%d)\n", parent, ret);
1121                 goto exit;
1122         }
1123
1124         retdent = find_directory_entry(itr, l_filename);
1125
1126         if (retdent) {
1127                 if (fat_itr_isdir(itr)) {
1128                         ret = -EISDIR;
1129                         goto exit;
1130                 }
1131
1132                 /* A file exists */
1133                 if (pos == -1)
1134                         /* Append to the end */
1135                         pos = FAT2CPU32(retdent->size);
1136                 if (pos > retdent->size) {
1137                         /* No hole allowed */
1138                         ret = -EINVAL;
1139                         goto exit;
1140                 }
1141
1142                 /* Update file size in a directory entry */
1143                 retdent->size = cpu_to_le32(pos + size);
1144         } else {
1145                 /* Create a new file */
1146
1147                 if (itr->is_root) {
1148                         /* root dir cannot have "." or ".." */
1149                         if (!strcmp(l_filename, ".") ||
1150                             !strcmp(l_filename, "..")) {
1151                                 ret = -EINVAL;
1152                                 goto exit;
1153                         }
1154                 }
1155
1156                 if (!itr->dent) {
1157                         printf("Error: allocating new dir entry\n");
1158                         ret = -EIO;
1159                         goto exit;
1160                 }
1161
1162                 if (pos) {
1163                         /* No hole allowed */
1164                         ret = -EINVAL;
1165                         goto exit;
1166                 }
1167
1168                 memset(itr->dent, 0, sizeof(*itr->dent));
1169
1170                 /* Calculate checksum for short name */
1171                 set_name(itr->dent, filename);
1172
1173                 /* Set long name entries */
1174                 if (fill_dir_slot(itr, filename)) {
1175                         ret = -EIO;
1176                         goto exit;
1177                 }
1178
1179                 /* Set short name entry */
1180                 fill_dentry(itr->fsdata, itr->dent, filename, 0, size, 0x20);
1181
1182                 retdent = itr->dent;
1183         }
1184
1185         ret = set_contents(mydata, retdent, pos, buffer, size, actwrite);
1186         if (ret < 0) {
1187                 printf("Error: writing contents\n");
1188                 ret = -EIO;
1189                 goto exit;
1190         }
1191         debug("attempt to write 0x%llx bytes\n", *actwrite);
1192
1193         /* Flush fat buffer */
1194         ret = flush_dirty_fat_buffer(mydata);
1195         if (ret) {
1196                 printf("Error: flush fat buffer\n");
1197                 ret = -EIO;
1198                 goto exit;
1199         }
1200
1201         /* Write directory table to device */
1202         ret = flush_dir(itr);
1203         if (ret) {
1204                 printf("Error: writing directory entry\n");
1205                 ret = -EIO;
1206         }
1207
1208 exit:
1209         free(filename_copy);
1210         free(mydata->fatbuf);
1211         free(itr);
1212         return ret;
1213 }
1214
1215 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1216                    loff_t maxsize, loff_t *actwrite)
1217 {
1218         return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
1219 }
1220
1221 static int fat_dir_entries(fat_itr *itr)
1222 {
1223         fat_itr *dirs;
1224         fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
1225                                                 /* for FATBUFSIZE */
1226         int count;
1227
1228         dirs = malloc_cache_aligned(sizeof(fat_itr));
1229         if (!dirs) {
1230                 debug("Error: allocating memory\n");
1231                 count = -ENOMEM;
1232                 goto exit;
1233         }
1234
1235         /* duplicate fsdata */
1236         fat_itr_child(dirs, itr);
1237         fsdata = *dirs->fsdata;
1238
1239         /* allocate local fat buffer */
1240         fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
1241         if (!fsdata.fatbuf) {
1242                 debug("Error: allocating memory\n");
1243                 count = -ENOMEM;
1244                 goto exit;
1245         }
1246         fsdata.fatbufnum = -1;
1247         dirs->fsdata = &fsdata;
1248
1249         for (count = 0; fat_itr_next(dirs); count++)
1250                 ;
1251
1252 exit:
1253         free(fsdata.fatbuf);
1254         free(dirs);
1255         return count;
1256 }
1257
1258 static int delete_dentry(fat_itr *itr)
1259 {
1260         fsdata *mydata = itr->fsdata;
1261         dir_entry *dentptr = itr->dent;
1262
1263         /* free cluster blocks */
1264         clear_fatent(mydata, START(dentptr));
1265         if (flush_dirty_fat_buffer(mydata) < 0) {
1266                 printf("Error: flush fat buffer\n");
1267                 return -EIO;
1268         }
1269
1270         /*
1271          * update a directory entry
1272          * TODO:
1273          *  - long file name support
1274          *  - find and mark the "new" first invalid entry as name[0]=0x00
1275          */
1276         memset(dentptr, 0, sizeof(*dentptr));
1277         dentptr->name[0] = 0xe5;
1278
1279         if (flush_dir(itr)) {
1280                 printf("error: writing directory entry\n");
1281                 return -EIO;
1282         }
1283
1284         return 0;
1285 }
1286
1287 int fat_unlink(const char *filename)
1288 {
1289         fsdata fsdata = { .fatbuf = NULL, };
1290         fat_itr *itr = NULL;
1291         int n_entries, ret;
1292         char *filename_copy, *dirname, *basename;
1293
1294         filename_copy = strdup(filename);
1295         if (!filename_copy) {
1296                 printf("Error: allocating memory\n");
1297                 ret = -ENOMEM;
1298                 goto exit;
1299         }
1300         split_filename(filename_copy, &dirname, &basename);
1301
1302         if (!strcmp(dirname, "/") && !strcmp(basename, "")) {
1303                 printf("Error: cannot remove root\n");
1304                 ret = -EINVAL;
1305                 goto exit;
1306         }
1307
1308         itr = malloc_cache_aligned(sizeof(fat_itr));
1309         if (!itr) {
1310                 printf("Error: allocating memory\n");
1311                 ret = -ENOMEM;
1312                 goto exit;
1313         }
1314
1315         ret = fat_itr_root(itr, &fsdata);
1316         if (ret)
1317                 goto exit;
1318
1319         total_sector = fsdata.total_sect;
1320
1321         ret = fat_itr_resolve(itr, dirname, TYPE_DIR);
1322         if (ret) {
1323                 printf("%s: doesn't exist (%d)\n", dirname, ret);
1324                 ret = -ENOENT;
1325                 goto exit;
1326         }
1327
1328         if (!find_directory_entry(itr, basename)) {
1329                 printf("%s: doesn't exist\n", basename);
1330                 ret = -ENOENT;
1331                 goto exit;
1332         }
1333
1334         if (fat_itr_isdir(itr)) {
1335                 n_entries = fat_dir_entries(itr);
1336                 if (n_entries < 0) {
1337                         ret = n_entries;
1338                         goto exit;
1339                 }
1340                 if (n_entries > 2) {
1341                         printf("Error: directory is not empty: %d\n",
1342                                n_entries);
1343                         ret = -EINVAL;
1344                         goto exit;
1345                 }
1346         }
1347
1348         ret = delete_dentry(itr);
1349
1350 exit:
1351         free(fsdata.fatbuf);
1352         free(itr);
1353         free(filename_copy);
1354
1355         return ret;
1356 }
1357
1358 int fat_mkdir(const char *new_dirname)
1359 {
1360         dir_entry *retdent;
1361         fsdata datablock = { .fatbuf = NULL, };
1362         fsdata *mydata = &datablock;
1363         fat_itr *itr = NULL;
1364         char *dirname_copy, *parent, *dirname;
1365         char l_dirname[VFAT_MAXLEN_BYTES];
1366         int ret = -1;
1367         loff_t actwrite;
1368         unsigned int bytesperclust;
1369         dir_entry *dotdent = NULL;
1370
1371         dirname_copy = strdup(new_dirname);
1372         if (!dirname_copy)
1373                 goto exit;
1374
1375         split_filename(dirname_copy, &parent, &dirname);
1376         if (!strlen(dirname)) {
1377                 ret = -EINVAL;
1378                 goto exit;
1379         }
1380
1381         if (normalize_longname(l_dirname, dirname)) {
1382                 printf("FAT: illegal filename (%s)\n", dirname);
1383                 ret = -EINVAL;
1384                 goto exit;
1385         }
1386
1387         itr = malloc_cache_aligned(sizeof(fat_itr));
1388         if (!itr) {
1389                 ret = -ENOMEM;
1390                 goto exit;
1391         }
1392
1393         ret = fat_itr_root(itr, &datablock);
1394         if (ret)
1395                 goto exit;
1396
1397         total_sector = datablock.total_sect;
1398
1399         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1400         if (ret) {
1401                 printf("%s: doesn't exist (%d)\n", parent, ret);
1402                 goto exit;
1403         }
1404
1405         retdent = find_directory_entry(itr, l_dirname);
1406
1407         if (retdent) {
1408                 printf("%s: already exists\n", l_dirname);
1409                 ret = -EEXIST;
1410                 goto exit;
1411         } else {
1412                 if (itr->is_root) {
1413                         /* root dir cannot have "." or ".." */
1414                         if (!strcmp(l_dirname, ".") ||
1415                             !strcmp(l_dirname, "..")) {
1416                                 ret = -EINVAL;
1417                                 goto exit;
1418                         }
1419                 }
1420
1421                 if (!itr->dent) {
1422                         printf("Error: allocating new dir entry\n");
1423                         ret = -EIO;
1424                         goto exit;
1425                 }
1426
1427                 memset(itr->dent, 0, sizeof(*itr->dent));
1428
1429                 /* Set short name to set alias checksum field in dir_slot */
1430                 set_name(itr->dent, dirname);
1431                 fill_dir_slot(itr, dirname);
1432
1433                 /* Set attribute as archive for regular file */
1434                 fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0,
1435                             ATTR_DIR | ATTR_ARCH);
1436
1437                 retdent = itr->dent;
1438         }
1439
1440         /* Default entries */
1441         bytesperclust = mydata->clust_size * mydata->sect_size;
1442         dotdent = malloc_cache_aligned(bytesperclust);
1443         if (!dotdent) {
1444                 ret = -ENOMEM;
1445                 goto exit;
1446         }
1447         memset(dotdent, 0, bytesperclust);
1448
1449         memcpy(dotdent[0].name, ".       ", 8);
1450         memcpy(dotdent[0].ext, "   ", 3);
1451         dotdent[0].attr = ATTR_DIR | ATTR_ARCH;
1452
1453         memcpy(dotdent[1].name, "..      ", 8);
1454         memcpy(dotdent[1].ext, "   ", 3);
1455         dotdent[1].attr = ATTR_DIR | ATTR_ARCH;
1456         set_start_cluster(mydata, &dotdent[1], itr->start_clust);
1457
1458         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1459                            bytesperclust, &actwrite);
1460         if (ret < 0) {
1461                 printf("Error: writing contents\n");
1462                 goto exit;
1463         }
1464         /* Write twice for "." */
1465         set_start_cluster(mydata, &dotdent[0], START(retdent));
1466         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1467                            bytesperclust, &actwrite);
1468         if (ret < 0) {
1469                 printf("Error: writing contents\n");
1470                 goto exit;
1471         }
1472
1473         /* Flush fat buffer */
1474         ret = flush_dirty_fat_buffer(mydata);
1475         if (ret) {
1476                 printf("Error: flush fat buffer\n");
1477                 goto exit;
1478         }
1479
1480         /* Write directory table to device */
1481         ret = flush_dir(itr);
1482         if (ret)
1483                 printf("Error: writing directory entry\n");
1484
1485 exit:
1486         free(dirname_copy);
1487         free(mydata->fatbuf);
1488         free(itr);
1489         free(dotdent);
1490         return ret;
1491 }