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 <log.h>
  13 #include <malloc.h>
  14 #include <asm/byteorder.h>
  15 #include <part.h>
  16 #include <asm/cache.h>
  17 #include <linux/ctype.h>
  18 #include <div64.h>
  19 #include <linux/math64.h>
  20 #include "fat.c"
  21
  22 static void uppercase(char *str, int len)
  23 {
  24         int i;
  25
  26         for (i = 0; i < len; i++) {
  27                 *str = toupper(*str);
  28                 str++;
  29         }
  30 }
  31
  32 static int total_sector;
  33 static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
  34 {
  35         ulong ret;
  36
  37         if (!cur_dev)
  38                 return -1;
  39
  40         if (cur_part_info.start + block + nr_blocks >
  41                 cur_part_info.start + total_sector) {
  42                 printf("error: overflow occurs\n");
  43                 return -1;
  44         }
  45
  46         ret = blk_dwrite(cur_dev, cur_part_info.start + block, nr_blocks, buf);
  47         if (nr_blocks && ret == 0)
  48                 return -1;
  49
  50         return ret;
  51 }
  52
  53 /**
  54  * set_name() - set short name in directory entry
  55  *
  56  * @dirent:     directory entry
  57  * @filename:   long file name
  58  */
  59 static void set_name(dir_entry *dirent, const char *filename)
  60 {
  61         char s_name[VFAT_MAXLEN_BYTES];
  62         char *period;
  63         int period_location, len, i, ext_num;
  64
  65         if (filename == NULL)
  66                 return;
  67
  68         len = strlen(filename);
  69         if (len == 0)
  70                 return;
  71
  72         strncpy(s_name, filename, VFAT_MAXLEN_BYTES - 1);
  73         s_name[VFAT_MAXLEN_BYTES - 1] = '\0';
  74         uppercase(s_name, len);
  75
  76         period = strchr(s_name, '.');
  77         if (period == NULL) {
  78                 period_location = len;
  79                 ext_num = 0;
  80         } else {
  81                 period_location = period - s_name;
  82                 ext_num = len - period_location - 1;
  83         }
  84
  85         /* Pad spaces when the length of file name is shorter than eight */
  86         if (period_location < 8) {
  87                 memcpy(dirent->name, s_name, period_location);
  88                 for (i = period_location; i < 8; i++)
  89                         dirent->name[i] = ' ';
  90         } else if (period_location == 8) {
  91                 memcpy(dirent->name, s_name, period_location);
  92         } else {
  93                 memcpy(dirent->name, s_name, 6);
  94                 /*
  95                  * TODO: Translating two long names with the same first six
  96                  *       characters to the same short name is utterly wrong.
  97                  *       Short names must be unique.
  98                  */
  99                 dirent->name[6] = '~';
 100                 dirent->name[7] = '1';
 101         }
 102
 103         if (ext_num < 3) {
 104                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
 105                 for (i = ext_num; i < 3; i++)
 106                         dirent->ext[i] = ' ';
 107         } else
 108                 memcpy(dirent->ext, s_name + period_location + 1, 3);
 109
 110         debug("name : %s\n", dirent->name);
 111         debug("ext : %s\n", dirent->ext);
 112 }
 113
 114 /*
 115  * Write fat buffer into block device
 116  */
 117 static int flush_dirty_fat_buffer(fsdata *mydata)
 118 {
 119         int getsize = FATBUFBLOCKS;
 120         __u32 fatlength = mydata->fatlength;
 121         __u8 *bufptr = mydata->fatbuf;
 122         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 123
 124         debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum,
 125               (int)mydata->fat_dirty);
 126
 127         if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1))
 128                 return 0;
 129
 130         /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 131         if (startblock + getsize > fatlength)
 132                 getsize = fatlength - startblock;
 133
 134         startblock += mydata->fat_sect;
 135
 136         /* Write FAT buf */
 137         if (disk_write(startblock, getsize, bufptr) < 0) {
 138                 debug("error: writing FAT blocks\n");
 139                 return -1;
 140         }
 141
 142         if (mydata->fats == 2) {
 143                 /* Update corresponding second FAT blocks */
 144                 startblock += mydata->fatlength;
 145                 if (disk_write(startblock, getsize, bufptr) < 0) {
 146                         debug("error: writing second FAT blocks\n");
 147                         return -1;
 148                 }
 149         }
 150         mydata->fat_dirty = 0;
 151
 152         return 0;
 153 }
 154
 155 /*
 156  * Set the file name information from 'name' into 'slotptr',
 157  */
 158 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 159 {
 160         int j, end_idx = 0;
 161
 162         for (j = 0; j <= 8; j += 2) {
 163                 if (name[*idx] == 0x00) {
 164                         slotptr->name0_4[j] = 0;
 165                         slotptr->name0_4[j + 1] = 0;
 166                         end_idx++;
 167                         goto name0_4;
 168                 }
 169                 slotptr->name0_4[j] = name[*idx];
 170                 (*idx)++;
 171                 end_idx++;
 172         }
 173         for (j = 0; j <= 10; j += 2) {
 174                 if (name[*idx] == 0x00) {
 175                         slotptr->name5_10[j] = 0;
 176                         slotptr->name5_10[j + 1] = 0;
 177                         end_idx++;
 178                         goto name5_10;
 179                 }
 180                 slotptr->name5_10[j] = name[*idx];
 181                 (*idx)++;
 182                 end_idx++;
 183         }
 184         for (j = 0; j <= 2; j += 2) {
 185                 if (name[*idx] == 0x00) {
 186                         slotptr->name11_12[j] = 0;
 187                         slotptr->name11_12[j + 1] = 0;
 188                         end_idx++;
 189                         goto name11_12;
 190                 }
 191                 slotptr->name11_12[j] = name[*idx];
 192                 (*idx)++;
 193                 end_idx++;
 194         }
 195
 196         if (name[*idx] == 0x00)
 197                 return 1;
 198
 199         return 0;
 200 /* Not used characters are filled with 0xff 0xff */
 201 name0_4:
 202         for (; end_idx < 5; end_idx++) {
 203                 slotptr->name0_4[end_idx * 2] = 0xff;
 204                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 205         }
 206         end_idx = 5;
 207 name5_10:
 208         end_idx -= 5;
 209         for (; end_idx < 6; end_idx++) {
 210                 slotptr->name5_10[end_idx * 2] = 0xff;
 211                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 212         }
 213         end_idx = 11;
 214 name11_12:
 215         end_idx -= 11;
 216         for (; end_idx < 2; end_idx++) {
 217                 slotptr->name11_12[end_idx * 2] = 0xff;
 218                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 219         }
 220
 221         return 1;
 222 }
 223
 224 static int new_dir_table(fat_itr *itr);
 225 static int flush_dir(fat_itr *itr);
 226
 227 /*
 228  * Fill dir_slot entries with appropriate name, id, and attr
 229  * 'itr' will point to a next entry
 230  */
 231 static int
 232 fill_dir_slot(fat_itr *itr, const char *l_name)
 233 {
 234         __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
 235         dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
 236         __u8 counter = 0, checksum;
 237         int idx = 0, ret;
 238
 239         /* Get short file name checksum value */
 240         checksum = mkcksum(itr->dent->name, itr->dent->ext);
 241
 242         do {
 243                 memset(slotptr, 0x00, sizeof(dir_slot));
 244                 ret = str2slot(slotptr, l_name, &idx);
 245                 slotptr->id = ++counter;
 246                 slotptr->attr = ATTR_VFAT;
 247                 slotptr->alias_checksum = checksum;
 248                 slotptr++;
 249         } while (ret == 0);
 250
 251         slotptr--;
 252         slotptr->id |= LAST_LONG_ENTRY_MASK;
 253
 254         while (counter >= 1) {
 255                 memcpy(itr->dent, slotptr, sizeof(dir_slot));
 256                 slotptr--;
 257                 counter--;
 258
 259                 if (itr->remaining == 0)
 260                         flush_dir(itr);
 261
 262                 /* allocate a cluster for more entries */
 263                 if (!fat_itr_next(itr))
 264                         if (!itr->dent &&
 265                             (!itr->is_root || itr->fsdata->fatsize == 32) &&
 266                             new_dir_table(itr))
 267                                 return -1;
 268         }
 269
 270         return 0;
 271 }
 272
 273 /*
 274  * Set the entry at index 'entry' in a FAT (12/16/32) table.
 275  */
 276 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 277 {
 278         __u32 bufnum, offset, off16;
 279         __u16 val1, val2;
 280
 281         switch (mydata->fatsize) {
 282         case 32:
 283                 bufnum = entry / FAT32BUFSIZE;
 284                 offset = entry - bufnum * FAT32BUFSIZE;
 285                 break;
 286         case 16:
 287                 bufnum = entry / FAT16BUFSIZE;
 288                 offset = entry - bufnum * FAT16BUFSIZE;
 289                 break;
 290         case 12:
 291                 bufnum = entry / FAT12BUFSIZE;
 292                 offset = entry - bufnum * FAT12BUFSIZE;
 293                 break;
 294         default:
 295                 /* Unsupported FAT size */
 296                 return -1;
 297         }
 298
 299         /* Read a new block of FAT entries into the cache. */
 300         if (bufnum != mydata->fatbufnum) {
 301                 int getsize = FATBUFBLOCKS;
 302                 __u8 *bufptr = mydata->fatbuf;
 303                 __u32 fatlength = mydata->fatlength;
 304                 __u32 startblock = bufnum * FATBUFBLOCKS;
 305
 306                 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 307                 if (startblock + getsize > fatlength)
 308                         getsize = fatlength - startblock;
 309
 310                 if (flush_dirty_fat_buffer(mydata) < 0)
 311                         return -1;
 312
 313                 startblock += mydata->fat_sect;
 314
 315                 if (disk_read(startblock, getsize, bufptr) < 0) {
 316                         debug("Error reading FAT blocks\n");
 317                         return -1;
 318                 }
 319                 mydata->fatbufnum = bufnum;
 320         }
 321
 322         /* Mark as dirty */
 323         mydata->fat_dirty = 1;
 324
 325         /* Set the actual entry */
 326         switch (mydata->fatsize) {
 327         case 32:
 328                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 329                 break;
 330         case 16:
 331                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 332                 break;
 333         case 12:
 334                 off16 = (offset * 3) / 4;
 335
 336                 switch (offset & 0x3) {
 337                 case 0:
 338                         val1 = cpu_to_le16(entry_value) & 0xfff;
 339                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
 340                         ((__u16 *)mydata->fatbuf)[off16] |= val1;
 341                         break;
 342                 case 1:
 343                         val1 = cpu_to_le16(entry_value) & 0xf;
 344                         val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
 345
 346                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
 347                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
 348
 349                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
 350                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 351                         break;
 352                 case 2:
 353                         val1 = cpu_to_le16(entry_value) & 0xff;
 354                         val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
 355
 356                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
 357                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
 358
 359                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
 360                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 361                         break;
 362                 case 3:
 363                         val1 = cpu_to_le16(entry_value) & 0xfff;
 364                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
 365                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
 366                         break;
 367                 default:
 368                         break;
 369                 }
 370
 371                 break;
 372         default:
 373                 return -1;
 374         }
 375
 376         return 0;
 377 }
 378
 379 /*
 380  * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
 381  * and link it to 'entry'. EOC marker is not set on returned entry.
 382  */
 383 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 384 {
 385         __u32 next_fat, next_entry = entry + 1;
 386
 387         while (1) {
 388                 next_fat = get_fatent(mydata, next_entry);
 389                 if (next_fat == 0) {
 390                         /* found free entry, link to entry */
 391                         set_fatent_value(mydata, entry, next_entry);
 392                         break;
 393                 }
 394                 next_entry++;
 395         }
 396         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 397                mydata->fatsize, entry, next_entry);
 398
 399         return next_entry;
 400 }
 401
 402 /**
 403  * set_sectors() - write data to sectors
 404  *
 405  * Write 'size' bytes from 'buffer' into the specified sector.
 406  *
 407  * @mydata:     data to be written
 408  * @startsect:  sector to be written to
 409  * @buffer:     data to be written
 410  * @size:       bytes to be written (but not more than the size of a cluster)
 411  * Return:      0 on success, -1 otherwise
 412  */
 413 static int
 414 set_sectors(fsdata *mydata, u32 startsect, u8 *buffer, u32 size)
 415 {
 416         u32 nsects = 0;
 417         int ret;
 418
 419         debug("startsect: %d\n", startsect);
 420
 421         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 422                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 423
 424                 debug("FAT: Misaligned buffer address (%p)\n", buffer);
 425
 426                 while (size >= mydata->sect_size) {
 427                         memcpy(tmpbuf, buffer, mydata->sect_size);
 428                         ret = disk_write(startsect++, 1, tmpbuf);
 429                         if (ret != 1) {
 430                                 debug("Error writing data (got %d)\n", ret);
 431                                 return -1;
 432                         }
 433
 434                         buffer += mydata->sect_size;
 435                         size -= mydata->sect_size;
 436                 }
 437         } else if (size >= mydata->sect_size) {
 438                 nsects = size / mydata->sect_size;
 439                 ret = disk_write(startsect, nsects, buffer);
 440                 if (ret != nsects) {
 441                         debug("Error writing data (got %d)\n", ret);
 442                         return -1;
 443                 }
 444
 445                 startsect += nsects;
 446                 buffer += nsects * mydata->sect_size;
 447                 size -= nsects * mydata->sect_size;
 448         }
 449
 450         if (size) {
 451                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 452                 /* Do not leak content of stack */
 453                 memset(tmpbuf, 0, mydata->sect_size);
 454                 memcpy(tmpbuf, buffer, size);
 455                 ret = disk_write(startsect, 1, tmpbuf);
 456                 if (ret != 1) {
 457                         debug("Error writing data (got %d)\n", ret);
 458                         return -1;
 459                 }
 460         }
 461
 462         return 0;
 463 }
 464
 465 /**
 466  * set_cluster() - write data to cluster
 467  *
 468  * Write 'size' bytes from 'buffer' into the specified cluster.
 469  *
 470  * @mydata:     data to be written
 471  * @clustnum:   cluster to be written to
 472  * @buffer:     data to be written
 473  * @size:       bytes to be written (but not more than the size of a cluster)
 474  * Return:      0 on success, -1 otherwise
 475  */
 476 static int
 477 set_cluster(fsdata *mydata, u32 clustnum, u8 *buffer, u32 size)
 478 {
 479         return set_sectors(mydata, clust_to_sect(mydata, clustnum),
 480                            buffer, size);
 481 }
 482
 483 static int
 484 flush_dir(fat_itr *itr)
 485 {
 486         fsdata *mydata = itr->fsdata;
 487         u32 startsect, sect_offset, nsects;
 488
 489         if (!itr->is_root || mydata->fatsize == 32)
 490                 return set_cluster(mydata, itr->clust, itr->block,
 491                                    mydata->clust_size * mydata->sect_size);
 492
 493         sect_offset = itr->clust * mydata->clust_size;
 494         startsect = mydata->rootdir_sect + sect_offset;
 495         /* do not write past the end of rootdir */
 496         nsects = min_t(u32, mydata->clust_size,
 497                        mydata->rootdir_size - sect_offset);
 498
 499         return set_sectors(mydata, startsect, itr->block,
 500                            nsects * mydata->sect_size);
 501 }
 502
 503 static __u8 tmpbuf_cluster[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
 504
 505 /*
 506  * Read and modify data on existing and consecutive cluster blocks
 507  */
 508 static int
 509 get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
 510                 loff_t size, loff_t *gotsize)
 511 {
 512         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 513         __u32 startsect;
 514         loff_t wsize;
 515         int clustcount, i, ret;
 516
 517         *gotsize = 0;
 518         if (!size)
 519                 return 0;
 520
 521         assert(pos < bytesperclust);
 522         startsect = clust_to_sect(mydata, clustnum);
 523
 524         debug("clustnum: %d, startsect: %d, pos: %lld\n",
 525               clustnum, startsect, pos);
 526
 527         /* partial write at beginning */
 528         if (pos) {
 529                 wsize = min(bytesperclust - pos, size);
 530                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 531                 if (ret != mydata->clust_size) {
 532                         debug("Error reading data (got %d)\n", ret);
 533                         return -1;
 534                 }
 535
 536                 memcpy(tmpbuf_cluster + pos, buffer, wsize);
 537                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 538                 if (ret != mydata->clust_size) {
 539                         debug("Error writing data (got %d)\n", ret);
 540                         return -1;
 541                 }
 542
 543                 size -= wsize;
 544                 buffer += wsize;
 545                 *gotsize += wsize;
 546
 547                 startsect += mydata->clust_size;
 548
 549                 if (!size)
 550                         return 0;
 551         }
 552
 553         /* full-cluster write */
 554         if (size >= bytesperclust) {
 555                 clustcount = lldiv(size, bytesperclust);
 556
 557                 if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
 558                         wsize = clustcount * bytesperclust;
 559                         ret = disk_write(startsect,
 560                                          clustcount * mydata->clust_size,
 561                                          buffer);
 562                         if (ret != clustcount * mydata->clust_size) {
 563                                 debug("Error writing data (got %d)\n", ret);
 564                                 return -1;
 565                         }
 566
 567                         size -= wsize;
 568                         buffer += wsize;
 569                         *gotsize += wsize;
 570
 571                         startsect += clustcount * mydata->clust_size;
 572                 } else {
 573                         for (i = 0; i < clustcount; i++) {
 574                                 memcpy(tmpbuf_cluster, buffer, bytesperclust);
 575                                 ret = disk_write(startsect,
 576                                                  mydata->clust_size,
 577                                                  tmpbuf_cluster);
 578                                 if (ret != mydata->clust_size) {
 579                                         debug("Error writing data (got %d)\n",
 580                                               ret);
 581                                         return -1;
 582                                 }
 583
 584                                 size -= bytesperclust;
 585                                 buffer += bytesperclust;
 586                                 *gotsize += bytesperclust;
 587
 588                                 startsect += mydata->clust_size;
 589                         }
 590                 }
 591         }
 592
 593         /* partial write at end */
 594         if (size) {
 595                 wsize = size;
 596                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 597                 if (ret != mydata->clust_size) {
 598                         debug("Error reading data (got %d)\n", ret);
 599                         return -1;
 600                 }
 601                 memcpy(tmpbuf_cluster, buffer, wsize);
 602                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 603                 if (ret != mydata->clust_size) {
 604                         debug("Error writing data (got %d)\n", ret);
 605                         return -1;
 606                 }
 607
 608                 size -= wsize;
 609                 buffer += wsize;
 610                 *gotsize += wsize;
 611         }
 612
 613         assert(!size);
 614
 615         return 0;
 616 }
 617
 618 /*
 619  * Find the first empty cluster
 620  */
 621 static int find_empty_cluster(fsdata *mydata)
 622 {
 623         __u32 fat_val, entry = 3;
 624
 625         while (1) {
 626                 fat_val = get_fatent(mydata, entry);
 627                 if (fat_val == 0)
 628                         break;
 629                 entry++;
 630         }
 631
 632         return entry;
 633 }
 634
 635 /*
 636  * Allocate a cluster for additional directory entries
 637  */
 638 static int new_dir_table(fat_itr *itr)
 639 {
 640         fsdata *mydata = itr->fsdata;
 641         int dir_newclust = 0;
 642         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 643
 644         dir_newclust = find_empty_cluster(mydata);
 645         set_fatent_value(mydata, itr->clust, dir_newclust);
 646         if (mydata->fatsize == 32)
 647                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 648         else if (mydata->fatsize == 16)
 649                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 650         else if (mydata->fatsize == 12)
 651                 set_fatent_value(mydata, dir_newclust, 0xff8);
 652
 653         itr->clust = dir_newclust;
 654         itr->next_clust = dir_newclust;
 655
 656         if (flush_dirty_fat_buffer(mydata) < 0)
 657                 return -1;
 658
 659         memset(itr->block, 0x00, bytesperclust);
 660
 661         itr->dent = (dir_entry *)itr->block;
 662         itr->last_cluster = 1;
 663         itr->remaining = bytesperclust / sizeof(dir_entry) - 1;
 664
 665         return 0;
 666 }
 667
 668 /*
 669  * Set empty cluster from 'entry' to the end of a file
 670  */
 671 static int clear_fatent(fsdata *mydata, __u32 entry)
 672 {
 673         __u32 fat_val;
 674
 675         while (!CHECK_CLUST(entry, mydata->fatsize)) {
 676                 fat_val = get_fatent(mydata, entry);
 677                 if (fat_val != 0)
 678                         set_fatent_value(mydata, entry, 0);
 679                 else
 680                         break;
 681
 682                 entry = fat_val;
 683         }
 684
 685         /* Flush fat buffer */
 686         if (flush_dirty_fat_buffer(mydata) < 0)
 687                 return -1;
 688
 689         return 0;
 690 }
 691
 692 /*
 693  * Set start cluster in directory entry
 694  */
 695 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 696                               __u32 start_cluster)
 697 {
 698         if (mydata->fatsize == 32)
 699                 dentptr->starthi =
 700                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 701         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 702 }
 703
 704 /*
 705  * Check whether adding a file makes the file system to
 706  * exceed the size of the block device
 707  * Return -1 when overflow occurs, otherwise return 0
 708  */
 709 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 710 {
 711         __u32 startsect, sect_num, offset;
 712
 713         if (clustnum > 0)
 714                 startsect = clust_to_sect(mydata, clustnum);
 715         else
 716                 startsect = mydata->rootdir_sect;
 717
 718         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 719
 720         if (offset != 0)
 721                 sect_num++;
 722
 723         if (startsect + sect_num > total_sector)
 724                 return -1;
 725         return 0;
 726 }
 727
 728 /*
 729  * Write at most 'maxsize' bytes from 'buffer' into
 730  * the file associated with 'dentptr'
 731  * Update the number of bytes written in *gotsize and return 0
 732  * or return -1 on fatal errors.
 733  */
 734 static int
 735 set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
 736              loff_t maxsize, loff_t *gotsize)
 737 {
 738         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 739         __u32 curclust = START(dentptr);
 740         __u32 endclust = 0, newclust = 0;
 741         u64 cur_pos, filesize;
 742         loff_t offset, actsize, wsize;
 743
 744         *gotsize = 0;
 745         filesize = pos + maxsize;
 746
 747         debug("%llu bytes\n", filesize);
 748
 749         if (!filesize) {
 750                 if (!curclust)
 751                         return 0;
 752                 if (!CHECK_CLUST(curclust, mydata->fatsize) ||
 753                     IS_LAST_CLUST(curclust, mydata->fatsize)) {
 754                         clear_fatent(mydata, curclust);
 755                         set_start_cluster(mydata, dentptr, 0);
 756                         return 0;
 757                 }
 758                 debug("curclust: 0x%x\n", curclust);
 759                 debug("Invalid FAT entry\n");
 760                 return -1;
 761         }
 762
 763         if (!curclust) {
 764                 assert(pos == 0);
 765                 goto set_clusters;
 766         }
 767
 768         /* go to cluster at pos */
 769         cur_pos = bytesperclust;
 770         while (1) {
 771                 if (pos <= cur_pos)
 772                         break;
 773                 if (IS_LAST_CLUST(curclust, mydata->fatsize))
 774                         break;
 775
 776                 newclust = get_fatent(mydata, curclust);
 777                 if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
 778                     CHECK_CLUST(newclust, mydata->fatsize)) {
 779                         debug("curclust: 0x%x\n", curclust);
 780                         debug("Invalid FAT entry\n");
 781                         return -1;
 782                 }
 783
 784                 cur_pos += bytesperclust;
 785                 curclust = newclust;
 786         }
 787         if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 788                 assert(pos == cur_pos);
 789                 goto set_clusters;
 790         }
 791
 792         assert(pos < cur_pos);
 793         cur_pos -= bytesperclust;
 794
 795         /* overwrite */
 796         assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
 797                !CHECK_CLUST(curclust, mydata->fatsize));
 798
 799         while (1) {
 800                 /* search for allocated consecutive clusters */
 801                 actsize = bytesperclust;
 802                 endclust = curclust;
 803                 while (1) {
 804                         if (filesize <= (cur_pos + actsize))
 805                                 break;
 806
 807                         newclust = get_fatent(mydata, endclust);
 808
 809                         if (newclust != endclust + 1)
 810                                 break;
 811                         if (IS_LAST_CLUST(newclust, mydata->fatsize))
 812                                 break;
 813                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 814                                 debug("curclust: 0x%x\n", curclust);
 815                                 debug("Invalid FAT entry\n");
 816                                 return -1;
 817                         }
 818
 819                         actsize += bytesperclust;
 820                         endclust = newclust;
 821                 }
 822
 823                 /* overwrite to <curclust..endclust> */
 824                 if (pos < cur_pos)
 825                         offset = 0;
 826                 else
 827                         offset = pos - cur_pos;
 828                 wsize = min_t(unsigned long long, actsize, filesize - cur_pos);
 829                 wsize -= offset;
 830
 831                 if (get_set_cluster(mydata, curclust, offset,
 832                                     buffer, wsize, &actsize)) {
 833                         printf("Error get-and-setting cluster\n");
 834                         return -1;
 835                 }
 836                 buffer += wsize;
 837                 *gotsize += wsize;
 838                 cur_pos += offset + wsize;
 839
 840                 if (filesize <= cur_pos)
 841                         break;
 842
 843                 if (IS_LAST_CLUST(newclust, mydata->fatsize))
 844                         /* no more clusters */
 845                         break;
 846
 847                 curclust = newclust;
 848         }
 849
 850         if (filesize <= cur_pos) {
 851                 /* no more write */
 852                 newclust = get_fatent(mydata, endclust);
 853                 if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
 854                         /* truncate the rest */
 855                         clear_fatent(mydata, newclust);
 856
 857                         /* Mark end of file in FAT */
 858                         if (mydata->fatsize == 12)
 859                                 newclust = 0xfff;
 860                         else if (mydata->fatsize == 16)
 861                                 newclust = 0xffff;
 862                         else if (mydata->fatsize == 32)
 863                                 newclust = 0xfffffff;
 864                         set_fatent_value(mydata, endclust, newclust);
 865                 }
 866
 867                 return 0;
 868         }
 869
 870         curclust = endclust;
 871         filesize -= cur_pos;
 872         assert(!do_div(cur_pos, bytesperclust));
 873
 874 set_clusters:
 875         /* allocate and write */
 876         assert(!pos);
 877
 878         /* Assure that curclust is valid */
 879         if (!curclust) {
 880                 curclust = find_empty_cluster(mydata);
 881                 set_start_cluster(mydata, dentptr, curclust);
 882         } else {
 883                 newclust = get_fatent(mydata, curclust);
 884
 885                 if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
 886                         newclust = determine_fatent(mydata, curclust);
 887                         set_fatent_value(mydata, curclust, newclust);
 888                         curclust = newclust;
 889                 } else {
 890                         debug("error: something wrong\n");
 891                         return -1;
 892                 }
 893         }
 894
 895         /* TODO: already partially written */
 896         if (check_overflow(mydata, curclust, filesize)) {
 897                 printf("Error: no space left: %llu\n", filesize);
 898                 return -1;
 899         }
 900
 901         actsize = bytesperclust;
 902         endclust = curclust;
 903         do {
 904                 /* search for consecutive clusters */
 905                 while (actsize < filesize) {
 906                         newclust = determine_fatent(mydata, endclust);
 907
 908                         if ((newclust - 1) != endclust)
 909                                 /* write to <curclust..endclust> */
 910                                 goto getit;
 911
 912                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 913                                 debug("newclust: 0x%x\n", newclust);
 914                                 debug("Invalid FAT entry\n");
 915                                 return 0;
 916                         }
 917                         endclust = newclust;
 918                         actsize += bytesperclust;
 919                 }
 920
 921                 /* set remaining bytes */
 922                 actsize = filesize;
 923                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 924                         debug("error: writing cluster\n");
 925                         return -1;
 926                 }
 927                 *gotsize += actsize;
 928
 929                 /* Mark end of file in FAT */
 930                 if (mydata->fatsize == 12)
 931                         newclust = 0xfff;
 932                 else if (mydata->fatsize == 16)
 933                         newclust = 0xffff;
 934                 else if (mydata->fatsize == 32)
 935                         newclust = 0xfffffff;
 936                 set_fatent_value(mydata, endclust, newclust);
 937
 938                 return 0;
 939 getit:
 940                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 941                         debug("error: writing cluster\n");
 942                         return -1;
 943                 }
 944                 *gotsize += actsize;
 945                 filesize -= actsize;
 946                 buffer += actsize;
 947
 948                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 949                         debug("newclust: 0x%x\n", newclust);
 950                         debug("Invalid FAT entry\n");
 951                         return 0;
 952                 }
 953                 actsize = bytesperclust;
 954                 curclust = endclust = newclust;
 955         } while (1);
 956
 957         return 0;
 958 }
 959
 960 /*
 961  * Fill dir_entry
 962  */
 963 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 964         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 965 {
 966         set_start_cluster(mydata, dentptr, start_cluster);
 967         dentptr->size = cpu_to_le32(size);
 968
 969         dentptr->attr = attr;
 970
 971         set_name(dentptr, filename);
 972 }
 973
 974 /*
 975  * Find a directory entry based on filename or start cluster number
 976  * If the directory entry is not found,
 977  * the new position for writing a directory entry will be returned
 978  */
 979 static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
 980 {
 981         int match = 0;
 982
 983         while (fat_itr_next(itr)) {
 984                 /* check both long and short name: */
 985                 if (!strcasecmp(filename, itr->name))
 986                         match = 1;
 987                 else if (itr->name != itr->s_name &&
 988                          !strcasecmp(filename, itr->s_name))
 989                         match = 1;
 990
 991                 if (!match)
 992                         continue;
 993
 994                 if (itr->dent->name[0] == '\0')
 995                         return NULL;
 996                 else
 997                         return itr->dent;
 998         }
 999
1000         /* allocate a cluster for more entries */
1001         if (!itr->dent &&
1002             (!itr->is_root || itr->fsdata->fatsize == 32) &&
1003             new_dir_table(itr))
1004                 /* indicate that allocating dent failed */
1005                 itr->dent = NULL;
1006
1007         return NULL;
1008 }
1009
1010 static int split_filename(char *filename, char **dirname, char **basename)
1011 {
1012         char *p, *last_slash, *last_slash_cont;
1013
1014 again:
1015         p = filename;
1016         last_slash = NULL;
1017         last_slash_cont = NULL;
1018         while (*p) {
1019                 if (ISDIRDELIM(*p)) {
1020                         last_slash = p;
1021                         last_slash_cont = p;
1022                         /* continuous slashes */
1023                         while (ISDIRDELIM(*p))
1024                                 last_slash_cont = p++;
1025                         if (!*p)
1026                                 break;
1027                 }
1028                 p++;
1029         }
1030
1031         if (last_slash) {
1032                 if (last_slash_cont == (filename + strlen(filename) - 1)) {
1033                         /* remove trailing slashes */
1034                         *last_slash = '\0';
1035                         goto again;
1036                 }
1037
1038                 if (last_slash == filename) {
1039                         /* avoid ""(null) directory */
1040                         *dirname = "/";
1041                 } else {
1042                         *last_slash = '\0';
1043                         *dirname = filename;
1044                 }
1045
1046                 *last_slash_cont = '\0';
1047                 *basename = last_slash_cont + 1;
1048         } else {
1049                 *dirname = "/"; /* root by default */
1050                 *basename = filename;
1051         }
1052
1053         return 0;
1054 }
1055
1056 /**
1057  * normalize_longname() - check long file name and convert to lower case
1058  *
1059  * We assume here that the FAT file system is using an 8bit code page.
1060  * Linux typically uses CP437, EDK2 assumes CP1250.
1061  *
1062  * @l_filename: preallocated buffer receiving the normalized name
1063  * @filename:   filename to normalize
1064  * Return:      0 on success, -1 on failure
1065  */
1066 static int normalize_longname(char *l_filename, const char *filename)
1067 {
1068         const char *p, illegal[] = "<>:\"/\\|?*";
1069
1070         if (strlen(filename) >= VFAT_MAXLEN_BYTES)
1071                 return -1;
1072
1073         for (p = filename; *p; ++p) {
1074                 if ((unsigned char)*p < 0x20)
1075                         return -1;
1076                 if (strchr(illegal, *p))
1077                         return -1;
1078         }
1079
1080         strcpy(l_filename, filename);
1081         downcase(l_filename, VFAT_MAXLEN_BYTES);
1082
1083         return 0;
1084 }
1085
1086 int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
1087                       loff_t size, loff_t *actwrite)
1088 {
1089         dir_entry *retdent;
1090         fsdata datablock = { .fatbuf = NULL, };
1091         fsdata *mydata = &datablock;
1092         fat_itr *itr = NULL;
1093         int ret = -1;
1094         char *filename_copy, *parent, *basename;
1095         char l_filename[VFAT_MAXLEN_BYTES];
1096
1097         debug("writing %s\n", filename);
1098
1099         filename_copy = strdup(filename);
1100         if (!filename_copy)
1101                 return -ENOMEM;
1102
1103         split_filename(filename_copy, &parent, &basename);
1104         if (!strlen(basename)) {
1105                 ret = -EINVAL;
1106                 goto exit;
1107         }
1108
1109         filename = basename;
1110         if (normalize_longname(l_filename, filename)) {
1111                 printf("FAT: illegal filename (%s)\n", filename);
1112                 ret = -EINVAL;
1113                 goto exit;
1114         }
1115
1116         itr = malloc_cache_aligned(sizeof(fat_itr));
1117         if (!itr) {
1118                 ret = -ENOMEM;
1119                 goto exit;
1120         }
1121
1122         ret = fat_itr_root(itr, &datablock);
1123         if (ret)
1124                 goto exit;
1125
1126         total_sector = datablock.total_sect;
1127
1128         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1129         if (ret) {
1130                 printf("%s: doesn't exist (%d)\n", parent, ret);
1131                 goto exit;
1132         }
1133
1134         retdent = find_directory_entry(itr, l_filename);
1135
1136         if (retdent) {
1137                 if (fat_itr_isdir(itr)) {
1138                         ret = -EISDIR;
1139                         goto exit;
1140                 }
1141
1142                 /* A file exists */
1143                 if (pos == -1)
1144                         /* Append to the end */
1145                         pos = FAT2CPU32(retdent->size);
1146                 if (pos > retdent->size) {
1147                         /* No hole allowed */
1148                         ret = -EINVAL;
1149                         goto exit;
1150                 }
1151
1152                 /* Update file size in a directory entry */
1153                 retdent->size = cpu_to_le32(pos + size);
1154         } else {
1155                 /* Create a new file */
1156
1157                 if (itr->is_root) {
1158                         /* root dir cannot have "." or ".." */
1159                         if (!strcmp(l_filename, ".") ||
1160                             !strcmp(l_filename, "..")) {
1161                                 ret = -EINVAL;
1162                                 goto exit;
1163                         }
1164                 }
1165
1166                 if (!itr->dent) {
1167                         printf("Error: allocating new dir entry\n");
1168                         ret = -EIO;
1169                         goto exit;
1170                 }
1171
1172                 if (pos) {
1173                         /* No hole allowed */
1174                         ret = -EINVAL;
1175                         goto exit;
1176                 }
1177
1178                 memset(itr->dent, 0, sizeof(*itr->dent));
1179
1180                 /* Calculate checksum for short name */
1181                 set_name(itr->dent, filename);
1182
1183                 /* Set long name entries */
1184                 if (fill_dir_slot(itr, filename)) {
1185                         ret = -EIO;
1186                         goto exit;
1187                 }
1188
1189                 /* Set short name entry */
1190                 fill_dentry(itr->fsdata, itr->dent, filename, 0, size, 0x20);
1191
1192                 retdent = itr->dent;
1193         }
1194
1195         ret = set_contents(mydata, retdent, pos, buffer, size, actwrite);
1196         if (ret < 0) {
1197                 printf("Error: writing contents\n");
1198                 ret = -EIO;
1199                 goto exit;
1200         }
1201         debug("attempt to write 0x%llx bytes\n", *actwrite);
1202
1203         /* Flush fat buffer */
1204         ret = flush_dirty_fat_buffer(mydata);
1205         if (ret) {
1206                 printf("Error: flush fat buffer\n");
1207                 ret = -EIO;
1208                 goto exit;
1209         }
1210
1211         /* Write directory table to device */
1212         ret = flush_dir(itr);
1213         if (ret) {
1214                 printf("Error: writing directory entry\n");
1215                 ret = -EIO;
1216         }
1217
1218 exit:
1219         free(filename_copy);
1220         free(mydata->fatbuf);
1221         free(itr);
1222         return ret;
1223 }
1224
1225 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1226                    loff_t maxsize, loff_t *actwrite)
1227 {
1228         return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
1229 }
1230
1231 static int fat_dir_entries(fat_itr *itr)
1232 {
1233         fat_itr *dirs;
1234         fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
1235                                                 /* for FATBUFSIZE */
1236         int count;
1237
1238         dirs = malloc_cache_aligned(sizeof(fat_itr));
1239         if (!dirs) {
1240                 debug("Error: allocating memory\n");
1241                 count = -ENOMEM;
1242                 goto exit;
1243         }
1244
1245         /* duplicate fsdata */
1246         fat_itr_child(dirs, itr);
1247         fsdata = *dirs->fsdata;
1248
1249         /* allocate local fat buffer */
1250         fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
1251         if (!fsdata.fatbuf) {
1252                 debug("Error: allocating memory\n");
1253                 count = -ENOMEM;
1254                 goto exit;
1255         }
1256         fsdata.fatbufnum = -1;
1257         dirs->fsdata = &fsdata;
1258
1259         for (count = 0; fat_itr_next(dirs); count++)
1260                 ;
1261
1262 exit:
1263         free(fsdata.fatbuf);
1264         free(dirs);
1265         return count;
1266 }
1267
1268 static int delete_dentry(fat_itr *itr)
1269 {
1270         fsdata *mydata = itr->fsdata;
1271         dir_entry *dentptr = itr->dent;
1272
1273         /* free cluster blocks */
1274         clear_fatent(mydata, START(dentptr));
1275         if (flush_dirty_fat_buffer(mydata) < 0) {
1276                 printf("Error: flush fat buffer\n");
1277                 return -EIO;
1278         }
1279
1280         /*
1281          * update a directory entry
1282          * TODO:
1283          *  - long file name support
1284          *  - find and mark the "new" first invalid entry as name[0]=0x00
1285          */
1286         memset(dentptr, 0, sizeof(*dentptr));
1287         dentptr->name[0] = 0xe5;
1288
1289         if (flush_dir(itr)) {
1290                 printf("error: writing directory entry\n");
1291                 return -EIO;
1292         }
1293
1294         return 0;
1295 }
1296
1297 int fat_unlink(const char *filename)
1298 {
1299         fsdata fsdata = { .fatbuf = NULL, };
1300         fat_itr *itr = NULL;
1301         int n_entries, ret;
1302         char *filename_copy, *dirname, *basename;
1303
1304         filename_copy = strdup(filename);
1305         if (!filename_copy) {
1306                 printf("Error: allocating memory\n");
1307                 ret = -ENOMEM;
1308                 goto exit;
1309         }
1310         split_filename(filename_copy, &dirname, &basename);
1311
1312         if (!strcmp(dirname, "/") && !strcmp(basename, "")) {
1313                 printf("Error: cannot remove root\n");
1314                 ret = -EINVAL;
1315                 goto exit;
1316         }
1317
1318         itr = malloc_cache_aligned(sizeof(fat_itr));
1319         if (!itr) {
1320                 printf("Error: allocating memory\n");
1321                 ret = -ENOMEM;
1322                 goto exit;
1323         }
1324
1325         ret = fat_itr_root(itr, &fsdata);
1326         if (ret)
1327                 goto exit;
1328
1329         total_sector = fsdata.total_sect;
1330
1331         ret = fat_itr_resolve(itr, dirname, TYPE_DIR);
1332         if (ret) {
1333                 printf("%s: doesn't exist (%d)\n", dirname, ret);
1334                 ret = -ENOENT;
1335                 goto exit;
1336         }
1337
1338         if (!find_directory_entry(itr, basename)) {
1339                 printf("%s: doesn't exist\n", basename);
1340                 ret = -ENOENT;
1341                 goto exit;
1342         }
1343
1344         if (fat_itr_isdir(itr)) {
1345                 n_entries = fat_dir_entries(itr);
1346                 if (n_entries < 0) {
1347                         ret = n_entries;
1348                         goto exit;
1349                 }
1350                 if (n_entries > 2) {
1351                         printf("Error: directory is not empty: %d\n",
1352                                n_entries);
1353                         ret = -EINVAL;
1354                         goto exit;
1355                 }
1356         }
1357
1358         ret = delete_dentry(itr);
1359
1360 exit:
1361         free(fsdata.fatbuf);
1362         free(itr);
1363         free(filename_copy);
1364
1365         return ret;
1366 }
1367
1368 int fat_mkdir(const char *new_dirname)
1369 {
1370         dir_entry *retdent;
1371         fsdata datablock = { .fatbuf = NULL, };
1372         fsdata *mydata = &datablock;
1373         fat_itr *itr = NULL;
1374         char *dirname_copy, *parent, *dirname;
1375         char l_dirname[VFAT_MAXLEN_BYTES];
1376         int ret = -1;
1377         loff_t actwrite;
1378         unsigned int bytesperclust;
1379         dir_entry *dotdent = NULL;
1380
1381         dirname_copy = strdup(new_dirname);
1382         if (!dirname_copy)
1383                 goto exit;
1384
1385         split_filename(dirname_copy, &parent, &dirname);
1386         if (!strlen(dirname)) {
1387                 ret = -EINVAL;
1388                 goto exit;
1389         }
1390
1391         if (normalize_longname(l_dirname, dirname)) {
1392                 printf("FAT: illegal filename (%s)\n", dirname);
1393                 ret = -EINVAL;
1394                 goto exit;
1395         }
1396
1397         itr = malloc_cache_aligned(sizeof(fat_itr));
1398         if (!itr) {
1399                 ret = -ENOMEM;
1400                 goto exit;
1401         }
1402
1403         ret = fat_itr_root(itr, &datablock);
1404         if (ret)
1405                 goto exit;
1406
1407         total_sector = datablock.total_sect;
1408
1409         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1410         if (ret) {
1411                 printf("%s: doesn't exist (%d)\n", parent, ret);
1412                 goto exit;
1413         }
1414
1415         retdent = find_directory_entry(itr, l_dirname);
1416
1417         if (retdent) {
1418                 printf("%s: already exists\n", l_dirname);
1419                 ret = -EEXIST;
1420                 goto exit;
1421         } else {
1422                 if (itr->is_root) {
1423                         /* root dir cannot have "." or ".." */
1424                         if (!strcmp(l_dirname, ".") ||
1425                             !strcmp(l_dirname, "..")) {
1426                                 ret = -EINVAL;
1427                                 goto exit;
1428                         }
1429                 }
1430
1431                 if (!itr->dent) {
1432                         printf("Error: allocating new dir entry\n");
1433                         ret = -EIO;
1434                         goto exit;
1435                 }
1436
1437                 memset(itr->dent, 0, sizeof(*itr->dent));
1438
1439                 /* Set short name to set alias checksum field in dir_slot */
1440                 set_name(itr->dent, dirname);
1441                 fill_dir_slot(itr, dirname);
1442
1443                 /* Set attribute as archive for regular file */
1444                 fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0,
1445                             ATTR_DIR | ATTR_ARCH);
1446
1447                 retdent = itr->dent;
1448         }
1449
1450         /* Default entries */
1451         bytesperclust = mydata->clust_size * mydata->sect_size;
1452         dotdent = malloc_cache_aligned(bytesperclust);
1453         if (!dotdent) {
1454                 ret = -ENOMEM;
1455                 goto exit;
1456         }
1457         memset(dotdent, 0, bytesperclust);
1458
1459         memcpy(dotdent[0].name, ".       ", 8);
1460         memcpy(dotdent[0].ext, "   ", 3);
1461         dotdent[0].attr = ATTR_DIR | ATTR_ARCH;
1462
1463         memcpy(dotdent[1].name, "..      ", 8);
1464         memcpy(dotdent[1].ext, "   ", 3);
1465         dotdent[1].attr = ATTR_DIR | ATTR_ARCH;
1466         set_start_cluster(mydata, &dotdent[1], itr->start_clust);
1467
1468         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1469                            bytesperclust, &actwrite);
1470         if (ret < 0) {
1471                 printf("Error: writing contents\n");
1472                 goto exit;
1473         }
1474         /* Write twice for "." */
1475         set_start_cluster(mydata, &dotdent[0], START(retdent));
1476         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1477                            bytesperclust, &actwrite);
1478         if (ret < 0) {
1479                 printf("Error: writing contents\n");
1480                 goto exit;
1481         }
1482
1483         /* Flush fat buffer */
1484         ret = flush_dirty_fat_buffer(mydata);
1485         if (ret) {
1486                 printf("Error: flush fat buffer\n");
1487                 goto exit;
1488         }
1489
1490         /* Write directory table to device */
1491         ret = flush_dir(itr);
1492         if (ret)
1493                 printf("Error: writing directory entry\n");
1494
1495 exit:
1496         free(dirname_copy);
1497         free(mydata->fatbuf);
1498         free(itr);
1499         free(dotdent);
1500         return ret;
1501 }