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) && !itr->dent)
 264                         if ((itr->is_root && itr->fsdata->fatsize != 32) ||
 265                             new_dir_table(itr))
 266                                 return -1;
 267         }
 268
 269         return 0;
 270 }
 271
 272 /*
 273  * Set the entry at index 'entry' in a FAT (12/16/32) table.
 274  */
 275 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 276 {
 277         __u32 bufnum, offset, off16;
 278         __u16 val1, val2;
 279
 280         switch (mydata->fatsize) {
 281         case 32:
 282                 bufnum = entry / FAT32BUFSIZE;
 283                 offset = entry - bufnum * FAT32BUFSIZE;
 284                 break;
 285         case 16:
 286                 bufnum = entry / FAT16BUFSIZE;
 287                 offset = entry - bufnum * FAT16BUFSIZE;
 288                 break;
 289         case 12:
 290                 bufnum = entry / FAT12BUFSIZE;
 291                 offset = entry - bufnum * FAT12BUFSIZE;
 292                 break;
 293         default:
 294                 /* Unsupported FAT size */
 295                 return -1;
 296         }
 297
 298         /* Read a new block of FAT entries into the cache. */
 299         if (bufnum != mydata->fatbufnum) {
 300                 int getsize = FATBUFBLOCKS;
 301                 __u8 *bufptr = mydata->fatbuf;
 302                 __u32 fatlength = mydata->fatlength;
 303                 __u32 startblock = bufnum * FATBUFBLOCKS;
 304
 305                 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 306                 if (startblock + getsize > fatlength)
 307                         getsize = fatlength - startblock;
 308
 309                 if (flush_dirty_fat_buffer(mydata) < 0)
 310                         return -1;
 311
 312                 startblock += mydata->fat_sect;
 313
 314                 if (disk_read(startblock, getsize, bufptr) < 0) {
 315                         debug("Error reading FAT blocks\n");
 316                         return -1;
 317                 }
 318                 mydata->fatbufnum = bufnum;
 319         }
 320
 321         /* Mark as dirty */
 322         mydata->fat_dirty = 1;
 323
 324         /* Set the actual entry */
 325         switch (mydata->fatsize) {
 326         case 32:
 327                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 328                 break;
 329         case 16:
 330                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 331                 break;
 332         case 12:
 333                 off16 = (offset * 3) / 4;
 334
 335                 switch (offset & 0x3) {
 336                 case 0:
 337                         val1 = cpu_to_le16(entry_value) & 0xfff;
 338                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
 339                         ((__u16 *)mydata->fatbuf)[off16] |= val1;
 340                         break;
 341                 case 1:
 342                         val1 = cpu_to_le16(entry_value) & 0xf;
 343                         val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
 344
 345                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
 346                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
 347
 348                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
 349                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 350                         break;
 351                 case 2:
 352                         val1 = cpu_to_le16(entry_value) & 0xff;
 353                         val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
 354
 355                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
 356                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
 357
 358                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
 359                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 360                         break;
 361                 case 3:
 362                         val1 = cpu_to_le16(entry_value) & 0xfff;
 363                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
 364                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
 365                         break;
 366                 default:
 367                         break;
 368                 }
 369
 370                 break;
 371         default:
 372                 return -1;
 373         }
 374
 375         return 0;
 376 }
 377
 378 /*
 379  * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
 380  * and link it to 'entry'. EOC marker is not set on returned entry.
 381  */
 382 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 383 {
 384         __u32 next_fat, next_entry = entry + 1;
 385
 386         while (1) {
 387                 next_fat = get_fatent(mydata, next_entry);
 388                 if (next_fat == 0) {
 389                         /* found free entry, link to entry */
 390                         set_fatent_value(mydata, entry, next_entry);
 391                         break;
 392                 }
 393                 next_entry++;
 394         }
 395         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 396                mydata->fatsize, entry, next_entry);
 397
 398         return next_entry;
 399 }
 400
 401 /**
 402  * set_sectors() - write data to sectors
 403  *
 404  * Write 'size' bytes from 'buffer' into the specified sector.
 405  *
 406  * @mydata:     data to be written
 407  * @startsect:  sector to be written to
 408  * @buffer:     data to be written
 409  * @size:       bytes to be written (but not more than the size of a cluster)
 410  * Return:      0 on success, -1 otherwise
 411  */
 412 static int
 413 set_sectors(fsdata *mydata, u32 startsect, u8 *buffer, u32 size)
 414 {
 415         u32 nsects = 0;
 416         int ret;
 417
 418         debug("startsect: %d\n", startsect);
 419
 420         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 421                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 422
 423                 debug("FAT: Misaligned buffer address (%p)\n", buffer);
 424
 425                 while (size >= mydata->sect_size) {
 426                         memcpy(tmpbuf, buffer, mydata->sect_size);
 427                         ret = disk_write(startsect++, 1, tmpbuf);
 428                         if (ret != 1) {
 429                                 debug("Error writing data (got %d)\n", ret);
 430                                 return -1;
 431                         }
 432
 433                         buffer += mydata->sect_size;
 434                         size -= mydata->sect_size;
 435                 }
 436         } else if (size >= mydata->sect_size) {
 437                 nsects = size / mydata->sect_size;
 438                 ret = disk_write(startsect, nsects, buffer);
 439                 if (ret != nsects) {
 440                         debug("Error writing data (got %d)\n", ret);
 441                         return -1;
 442                 }
 443
 444                 startsect += nsects;
 445                 buffer += nsects * mydata->sect_size;
 446                 size -= nsects * mydata->sect_size;
 447         }
 448
 449         if (size) {
 450                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 451                 /* Do not leak content of stack */
 452                 memset(tmpbuf, 0, mydata->sect_size);
 453                 memcpy(tmpbuf, buffer, size);
 454                 ret = disk_write(startsect, 1, tmpbuf);
 455                 if (ret != 1) {
 456                         debug("Error writing data (got %d)\n", ret);
 457                         return -1;
 458                 }
 459         }
 460
 461         return 0;
 462 }
 463
 464 /**
 465  * set_cluster() - write data to cluster
 466  *
 467  * Write 'size' bytes from 'buffer' into the specified cluster.
 468  *
 469  * @mydata:     data to be written
 470  * @clustnum:   cluster to be written to
 471  * @buffer:     data to be written
 472  * @size:       bytes to be written (but not more than the size of a cluster)
 473  * Return:      0 on success, -1 otherwise
 474  */
 475 static int
 476 set_cluster(fsdata *mydata, u32 clustnum, u8 *buffer, u32 size)
 477 {
 478         return set_sectors(mydata, clust_to_sect(mydata, clustnum),
 479                            buffer, size);
 480 }
 481
 482 static int
 483 flush_dir(fat_itr *itr)
 484 {
 485         fsdata *mydata = itr->fsdata;
 486         u32 startsect, sect_offset, nsects;
 487
 488         if (!itr->is_root || mydata->fatsize == 32)
 489                 return set_cluster(mydata, itr->clust, itr->block,
 490                                    mydata->clust_size * mydata->sect_size);
 491
 492         sect_offset = itr->clust * mydata->clust_size;
 493         startsect = mydata->rootdir_sect + sect_offset;
 494         /* do not write past the end of rootdir */
 495         nsects = min_t(u32, mydata->clust_size,
 496                        mydata->rootdir_size - sect_offset);
 497
 498         return set_sectors(mydata, startsect, itr->block,
 499                            nsects * mydata->sect_size);
 500 }
 501
 502 /*
 503  * Read and modify data on existing and consecutive cluster blocks
 504  */
 505 static int
 506 get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
 507                 loff_t size, loff_t *gotsize)
 508 {
 509         static u8 *tmpbuf_cluster;
 510         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 511         __u32 startsect;
 512         loff_t wsize;
 513         int clustcount, i, ret;
 514
 515         *gotsize = 0;
 516         if (!size)
 517                 return 0;
 518
 519         if (!tmpbuf_cluster) {
 520                 tmpbuf_cluster = memalign(ARCH_DMA_MINALIGN, MAX_CLUSTSIZE);
 521                 if (!tmpbuf_cluster)
 522                         return -1;
 523         }
 524
 525         assert(pos < bytesperclust);
 526         startsect = clust_to_sect(mydata, clustnum);
 527
 528         debug("clustnum: %d, startsect: %d, pos: %lld\n",
 529               clustnum, startsect, pos);
 530
 531         /* partial write at beginning */
 532         if (pos) {
 533                 wsize = min(bytesperclust - pos, size);
 534                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 535                 if (ret != mydata->clust_size) {
 536                         debug("Error reading data (got %d)\n", ret);
 537                         return -1;
 538                 }
 539
 540                 memcpy(tmpbuf_cluster + pos, buffer, wsize);
 541                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 542                 if (ret != mydata->clust_size) {
 543                         debug("Error writing data (got %d)\n", ret);
 544                         return -1;
 545                 }
 546
 547                 size -= wsize;
 548                 buffer += wsize;
 549                 *gotsize += wsize;
 550
 551                 startsect += mydata->clust_size;
 552
 553                 if (!size)
 554                         return 0;
 555         }
 556
 557         /* full-cluster write */
 558         if (size >= bytesperclust) {
 559                 clustcount = lldiv(size, bytesperclust);
 560
 561                 if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
 562                         wsize = clustcount * bytesperclust;
 563                         ret = disk_write(startsect,
 564                                          clustcount * mydata->clust_size,
 565                                          buffer);
 566                         if (ret != clustcount * mydata->clust_size) {
 567                                 debug("Error writing data (got %d)\n", ret);
 568                                 return -1;
 569                         }
 570
 571                         size -= wsize;
 572                         buffer += wsize;
 573                         *gotsize += wsize;
 574
 575                         startsect += clustcount * mydata->clust_size;
 576                 } else {
 577                         for (i = 0; i < clustcount; i++) {
 578                                 memcpy(tmpbuf_cluster, buffer, bytesperclust);
 579                                 ret = disk_write(startsect,
 580                                                  mydata->clust_size,
 581                                                  tmpbuf_cluster);
 582                                 if (ret != mydata->clust_size) {
 583                                         debug("Error writing data (got %d)\n",
 584                                               ret);
 585                                         return -1;
 586                                 }
 587
 588                                 size -= bytesperclust;
 589                                 buffer += bytesperclust;
 590                                 *gotsize += bytesperclust;
 591
 592                                 startsect += mydata->clust_size;
 593                         }
 594                 }
 595         }
 596
 597         /* partial write at end */
 598         if (size) {
 599                 wsize = size;
 600                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
 601                 if (ret != mydata->clust_size) {
 602                         debug("Error reading data (got %d)\n", ret);
 603                         return -1;
 604                 }
 605                 memcpy(tmpbuf_cluster, buffer, wsize);
 606                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
 607                 if (ret != mydata->clust_size) {
 608                         debug("Error writing data (got %d)\n", ret);
 609                         return -1;
 610                 }
 611
 612                 size -= wsize;
 613                 buffer += wsize;
 614                 *gotsize += wsize;
 615         }
 616
 617         assert(!size);
 618
 619         return 0;
 620 }
 621
 622 /*
 623  * Find the first empty cluster
 624  */
 625 static int find_empty_cluster(fsdata *mydata)
 626 {
 627         __u32 fat_val, entry = 3;
 628
 629         while (1) {
 630                 fat_val = get_fatent(mydata, entry);
 631                 if (fat_val == 0)
 632                         break;
 633                 entry++;
 634         }
 635
 636         return entry;
 637 }
 638
 639 /*
 640  * Allocate a cluster for additional directory entries
 641  */
 642 static int new_dir_table(fat_itr *itr)
 643 {
 644         fsdata *mydata = itr->fsdata;
 645         int dir_newclust = 0;
 646         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 647
 648         dir_newclust = find_empty_cluster(mydata);
 649         set_fatent_value(mydata, itr->clust, dir_newclust);
 650         if (mydata->fatsize == 32)
 651                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 652         else if (mydata->fatsize == 16)
 653                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 654         else if (mydata->fatsize == 12)
 655                 set_fatent_value(mydata, dir_newclust, 0xff8);
 656
 657         itr->clust = dir_newclust;
 658         itr->next_clust = dir_newclust;
 659
 660         if (flush_dirty_fat_buffer(mydata) < 0)
 661                 return -1;
 662
 663         memset(itr->block, 0x00, bytesperclust);
 664
 665         itr->dent = (dir_entry *)itr->block;
 666         itr->last_cluster = 1;
 667         itr->remaining = bytesperclust / sizeof(dir_entry) - 1;
 668
 669         return 0;
 670 }
 671
 672 /*
 673  * Set empty cluster from 'entry' to the end of a file
 674  */
 675 static int clear_fatent(fsdata *mydata, __u32 entry)
 676 {
 677         __u32 fat_val;
 678
 679         while (!CHECK_CLUST(entry, mydata->fatsize)) {
 680                 fat_val = get_fatent(mydata, entry);
 681                 if (fat_val != 0)
 682                         set_fatent_value(mydata, entry, 0);
 683                 else
 684                         break;
 685
 686                 entry = fat_val;
 687         }
 688
 689         /* Flush fat buffer */
 690         if (flush_dirty_fat_buffer(mydata) < 0)
 691                 return -1;
 692
 693         return 0;
 694 }
 695
 696 /*
 697  * Set start cluster in directory entry
 698  */
 699 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 700                               __u32 start_cluster)
 701 {
 702         if (mydata->fatsize == 32)
 703                 dentptr->starthi =
 704                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 705         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 706 }
 707
 708 /*
 709  * Check whether adding a file makes the file system to
 710  * exceed the size of the block device
 711  * Return -1 when overflow occurs, otherwise return 0
 712  */
 713 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 714 {
 715         __u32 startsect, sect_num, offset;
 716
 717         if (clustnum > 0)
 718                 startsect = clust_to_sect(mydata, clustnum);
 719         else
 720                 startsect = mydata->rootdir_sect;
 721
 722         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 723
 724         if (offset != 0)
 725                 sect_num++;
 726
 727         if (startsect + sect_num > total_sector)
 728                 return -1;
 729         return 0;
 730 }
 731
 732 /*
 733  * Write at most 'maxsize' bytes from 'buffer' into
 734  * the file associated with 'dentptr'
 735  * Update the number of bytes written in *gotsize and return 0
 736  * or return -1 on fatal errors.
 737  */
 738 static int
 739 set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
 740              loff_t maxsize, loff_t *gotsize)
 741 {
 742         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 743         __u32 curclust = START(dentptr);
 744         __u32 endclust = 0, newclust = 0;
 745         u64 cur_pos, filesize;
 746         loff_t offset, actsize, wsize;
 747
 748         *gotsize = 0;
 749         filesize = pos + maxsize;
 750
 751         debug("%llu bytes\n", filesize);
 752
 753         if (!filesize) {
 754                 if (!curclust)
 755                         return 0;
 756                 if (!CHECK_CLUST(curclust, mydata->fatsize) ||
 757                     IS_LAST_CLUST(curclust, mydata->fatsize)) {
 758                         clear_fatent(mydata, curclust);
 759                         set_start_cluster(mydata, dentptr, 0);
 760                         return 0;
 761                 }
 762                 debug("curclust: 0x%x\n", curclust);
 763                 debug("Invalid FAT entry\n");
 764                 return -1;
 765         }
 766
 767         if (!curclust) {
 768                 assert(pos == 0);
 769                 goto set_clusters;
 770         }
 771
 772         /* go to cluster at pos */
 773         cur_pos = bytesperclust;
 774         while (1) {
 775                 if (pos <= cur_pos)
 776                         break;
 777                 if (IS_LAST_CLUST(curclust, mydata->fatsize))
 778                         break;
 779
 780                 newclust = get_fatent(mydata, curclust);
 781                 if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
 782                     CHECK_CLUST(newclust, mydata->fatsize)) {
 783                         debug("curclust: 0x%x\n", curclust);
 784                         debug("Invalid FAT entry\n");
 785                         return -1;
 786                 }
 787
 788                 cur_pos += bytesperclust;
 789                 curclust = newclust;
 790         }
 791         if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 792                 assert(pos == cur_pos);
 793                 goto set_clusters;
 794         }
 795
 796         assert(pos < cur_pos);
 797         cur_pos -= bytesperclust;
 798
 799         /* overwrite */
 800         assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
 801                !CHECK_CLUST(curclust, mydata->fatsize));
 802
 803         while (1) {
 804                 /* search for allocated consecutive clusters */
 805                 actsize = bytesperclust;
 806                 endclust = curclust;
 807                 while (1) {
 808                         if (filesize <= (cur_pos + actsize))
 809                                 break;
 810
 811                         newclust = get_fatent(mydata, endclust);
 812
 813                         if (newclust != endclust + 1)
 814                                 break;
 815                         if (IS_LAST_CLUST(newclust, mydata->fatsize))
 816                                 break;
 817                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 818                                 debug("curclust: 0x%x\n", curclust);
 819                                 debug("Invalid FAT entry\n");
 820                                 return -1;
 821                         }
 822
 823                         actsize += bytesperclust;
 824                         endclust = newclust;
 825                 }
 826
 827                 /* overwrite to <curclust..endclust> */
 828                 if (pos < cur_pos)
 829                         offset = 0;
 830                 else
 831                         offset = pos - cur_pos;
 832                 wsize = min_t(unsigned long long, actsize, filesize - cur_pos);
 833                 wsize -= offset;
 834
 835                 if (get_set_cluster(mydata, curclust, offset,
 836                                     buffer, wsize, &actsize)) {
 837                         printf("Error get-and-setting cluster\n");
 838                         return -1;
 839                 }
 840                 buffer += wsize;
 841                 *gotsize += wsize;
 842                 cur_pos += offset + wsize;
 843
 844                 if (filesize <= cur_pos)
 845                         break;
 846
 847                 if (IS_LAST_CLUST(newclust, mydata->fatsize))
 848                         /* no more clusters */
 849                         break;
 850
 851                 curclust = newclust;
 852         }
 853
 854         if (filesize <= cur_pos) {
 855                 /* no more write */
 856                 newclust = get_fatent(mydata, endclust);
 857                 if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
 858                         /* truncate the rest */
 859                         clear_fatent(mydata, newclust);
 860
 861                         /* Mark end of file in FAT */
 862                         if (mydata->fatsize == 12)
 863                                 newclust = 0xfff;
 864                         else if (mydata->fatsize == 16)
 865                                 newclust = 0xffff;
 866                         else if (mydata->fatsize == 32)
 867                                 newclust = 0xfffffff;
 868                         set_fatent_value(mydata, endclust, newclust);
 869                 }
 870
 871                 return 0;
 872         }
 873
 874         curclust = endclust;
 875         filesize -= cur_pos;
 876         assert(!do_div(cur_pos, bytesperclust));
 877
 878 set_clusters:
 879         /* allocate and write */
 880         assert(!pos);
 881
 882         /* Assure that curclust is valid */
 883         if (!curclust) {
 884                 curclust = find_empty_cluster(mydata);
 885                 set_start_cluster(mydata, dentptr, curclust);
 886         } else {
 887                 newclust = get_fatent(mydata, curclust);
 888
 889                 if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
 890                         newclust = determine_fatent(mydata, curclust);
 891                         set_fatent_value(mydata, curclust, newclust);
 892                         curclust = newclust;
 893                 } else {
 894                         debug("error: something wrong\n");
 895                         return -1;
 896                 }
 897         }
 898
 899         /* TODO: already partially written */
 900         if (check_overflow(mydata, curclust, filesize)) {
 901                 printf("Error: no space left: %llu\n", filesize);
 902                 return -1;
 903         }
 904
 905         actsize = bytesperclust;
 906         endclust = curclust;
 907         do {
 908                 /* search for consecutive clusters */
 909                 while (actsize < filesize) {
 910                         newclust = determine_fatent(mydata, endclust);
 911
 912                         if ((newclust - 1) != endclust)
 913                                 /* write to <curclust..endclust> */
 914                                 goto getit;
 915
 916                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 917                                 debug("newclust: 0x%x\n", newclust);
 918                                 debug("Invalid FAT entry\n");
 919                                 return 0;
 920                         }
 921                         endclust = newclust;
 922                         actsize += bytesperclust;
 923                 }
 924
 925                 /* set remaining bytes */
 926                 actsize = filesize;
 927                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 928                         debug("error: writing cluster\n");
 929                         return -1;
 930                 }
 931                 *gotsize += actsize;
 932
 933                 /* Mark end of file in FAT */
 934                 if (mydata->fatsize == 12)
 935                         newclust = 0xfff;
 936                 else if (mydata->fatsize == 16)
 937                         newclust = 0xffff;
 938                 else if (mydata->fatsize == 32)
 939                         newclust = 0xfffffff;
 940                 set_fatent_value(mydata, endclust, newclust);
 941
 942                 return 0;
 943 getit:
 944                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
 945                         debug("error: writing cluster\n");
 946                         return -1;
 947                 }
 948                 *gotsize += actsize;
 949                 filesize -= actsize;
 950                 buffer += actsize;
 951
 952                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 953                         debug("newclust: 0x%x\n", newclust);
 954                         debug("Invalid FAT entry\n");
 955                         return 0;
 956                 }
 957                 actsize = bytesperclust;
 958                 curclust = endclust = newclust;
 959         } while (1);
 960
 961         return 0;
 962 }
 963
 964 /*
 965  * Fill dir_entry
 966  */
 967 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 968         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 969 {
 970         set_start_cluster(mydata, dentptr, start_cluster);
 971         dentptr->size = cpu_to_le32(size);
 972
 973         dentptr->attr = attr;
 974
 975         set_name(dentptr, filename);
 976 }
 977
 978 /*
 979  * Find a directory entry based on filename or start cluster number
 980  * If the directory entry is not found,
 981  * the new position for writing a directory entry will be returned
 982  */
 983 static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
 984 {
 985         int match = 0;
 986
 987         while (fat_itr_next(itr)) {
 988                 /* check both long and short name: */
 989                 if (!strcasecmp(filename, itr->name))
 990                         match = 1;
 991                 else if (itr->name != itr->s_name &&
 992                          !strcasecmp(filename, itr->s_name))
 993                         match = 1;
 994
 995                 if (!match)
 996                         continue;
 997
 998                 if (itr->dent->name[0] == '\0')
 999                         return NULL;
1000                 else
1001                         return itr->dent;
1002         }
1003
1004         /* allocate a cluster for more entries */
1005         if (!itr->dent &&
1006             (!itr->is_root || itr->fsdata->fatsize == 32) &&
1007             new_dir_table(itr))
1008                 /* indicate that allocating dent failed */
1009                 itr->dent = NULL;
1010
1011         return NULL;
1012 }
1013
1014 static int split_filename(char *filename, char **dirname, char **basename)
1015 {
1016         char *p, *last_slash, *last_slash_cont;
1017
1018 again:
1019         p = filename;
1020         last_slash = NULL;
1021         last_slash_cont = NULL;
1022         while (*p) {
1023                 if (ISDIRDELIM(*p)) {
1024                         last_slash = p;
1025                         last_slash_cont = p;
1026                         /* continuous slashes */
1027                         while (ISDIRDELIM(*p))
1028                                 last_slash_cont = p++;
1029                         if (!*p)
1030                                 break;
1031                 }
1032                 p++;
1033         }
1034
1035         if (last_slash) {
1036                 if (last_slash_cont == (filename + strlen(filename) - 1)) {
1037                         /* remove trailing slashes */
1038                         *last_slash = '\0';
1039                         goto again;
1040                 }
1041
1042                 if (last_slash == filename) {
1043                         /* avoid ""(null) directory */
1044                         *dirname = "/";
1045                 } else {
1046                         *last_slash = '\0';
1047                         *dirname = filename;
1048                 }
1049
1050                 *last_slash_cont = '\0';
1051                 *basename = last_slash_cont + 1;
1052         } else {
1053                 *dirname = "/"; /* root by default */
1054                 *basename = filename;
1055         }
1056
1057         return 0;
1058 }
1059
1060 /**
1061  * normalize_longname() - check long file name and convert to lower case
1062  *
1063  * We assume here that the FAT file system is using an 8bit code page.
1064  * Linux typically uses CP437, EDK2 assumes CP1250.
1065  *
1066  * @l_filename: preallocated buffer receiving the normalized name
1067  * @filename:   filename to normalize
1068  * Return:      0 on success, -1 on failure
1069  */
1070 static int normalize_longname(char *l_filename, const char *filename)
1071 {
1072         const char *p, illegal[] = "<>:\"/\\|?*";
1073
1074         if (strlen(filename) >= VFAT_MAXLEN_BYTES)
1075                 return -1;
1076
1077         for (p = filename; *p; ++p) {
1078                 if ((unsigned char)*p < 0x20)
1079                         return -1;
1080                 if (strchr(illegal, *p))
1081                         return -1;
1082         }
1083
1084         strcpy(l_filename, filename);
1085         downcase(l_filename, VFAT_MAXLEN_BYTES);
1086
1087         return 0;
1088 }
1089
1090 int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
1091                       loff_t size, loff_t *actwrite)
1092 {
1093         dir_entry *retdent;
1094         fsdata datablock = { .fatbuf = NULL, };
1095         fsdata *mydata = &datablock;
1096         fat_itr *itr = NULL;
1097         int ret = -1;
1098         char *filename_copy, *parent, *basename;
1099         char l_filename[VFAT_MAXLEN_BYTES];
1100
1101         debug("writing %s\n", filename);
1102
1103         filename_copy = strdup(filename);
1104         if (!filename_copy)
1105                 return -ENOMEM;
1106
1107         split_filename(filename_copy, &parent, &basename);
1108         if (!strlen(basename)) {
1109                 ret = -EINVAL;
1110                 goto exit;
1111         }
1112
1113         filename = basename;
1114         if (normalize_longname(l_filename, filename)) {
1115                 printf("FAT: illegal filename (%s)\n", filename);
1116                 ret = -EINVAL;
1117                 goto exit;
1118         }
1119
1120         itr = malloc_cache_aligned(sizeof(fat_itr));
1121         if (!itr) {
1122                 ret = -ENOMEM;
1123                 goto exit;
1124         }
1125
1126         ret = fat_itr_root(itr, &datablock);
1127         if (ret)
1128                 goto exit;
1129
1130         total_sector = datablock.total_sect;
1131
1132         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1133         if (ret) {
1134                 printf("%s: doesn't exist (%d)\n", parent, ret);
1135                 goto exit;
1136         }
1137
1138         retdent = find_directory_entry(itr, l_filename);
1139
1140         if (retdent) {
1141                 if (fat_itr_isdir(itr)) {
1142                         ret = -EISDIR;
1143                         goto exit;
1144                 }
1145
1146                 /* A file exists */
1147                 if (pos == -1)
1148                         /* Append to the end */
1149                         pos = FAT2CPU32(retdent->size);
1150                 if (pos > retdent->size) {
1151                         /* No hole allowed */
1152                         ret = -EINVAL;
1153                         goto exit;
1154                 }
1155
1156                 /* Update file size in a directory entry */
1157                 retdent->size = cpu_to_le32(pos + size);
1158         } else {
1159                 /* Create a new file */
1160
1161                 if (itr->is_root) {
1162                         /* root dir cannot have "." or ".." */
1163                         if (!strcmp(l_filename, ".") ||
1164                             !strcmp(l_filename, "..")) {
1165                                 ret = -EINVAL;
1166                                 goto exit;
1167                         }
1168                 }
1169
1170                 if (!itr->dent) {
1171                         printf("Error: allocating new dir entry\n");
1172                         ret = -EIO;
1173                         goto exit;
1174                 }
1175
1176                 if (pos) {
1177                         /* No hole allowed */
1178                         ret = -EINVAL;
1179                         goto exit;
1180                 }
1181
1182                 memset(itr->dent, 0, sizeof(*itr->dent));
1183
1184                 /* Calculate checksum for short name */
1185                 set_name(itr->dent, filename);
1186
1187                 /* Set long name entries */
1188                 if (fill_dir_slot(itr, filename)) {
1189                         ret = -EIO;
1190                         goto exit;
1191                 }
1192
1193                 /* Set short name entry */
1194                 fill_dentry(itr->fsdata, itr->dent, filename, 0, size,
1195                             ATTR_ARCH);
1196
1197                 retdent = itr->dent;
1198         }
1199
1200         ret = set_contents(mydata, retdent, pos, buffer, size, actwrite);
1201         if (ret < 0) {
1202                 printf("Error: writing contents\n");
1203                 ret = -EIO;
1204                 goto exit;
1205         }
1206         debug("attempt to write 0x%llx bytes\n", *actwrite);
1207
1208         /* Flush fat buffer */
1209         ret = flush_dirty_fat_buffer(mydata);
1210         if (ret) {
1211                 printf("Error: flush fat buffer\n");
1212                 ret = -EIO;
1213                 goto exit;
1214         }
1215
1216         /* Write directory table to device */
1217         ret = flush_dir(itr);
1218         if (ret) {
1219                 printf("Error: writing directory entry\n");
1220                 ret = -EIO;
1221         }
1222
1223 exit:
1224         free(filename_copy);
1225         free(mydata->fatbuf);
1226         free(itr);
1227         return ret;
1228 }
1229
1230 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1231                    loff_t maxsize, loff_t *actwrite)
1232 {
1233         return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
1234 }
1235
1236 static int fat_dir_entries(fat_itr *itr)
1237 {
1238         fat_itr *dirs;
1239         fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
1240                                                 /* for FATBUFSIZE */
1241         int count;
1242
1243         dirs = malloc_cache_aligned(sizeof(fat_itr));
1244         if (!dirs) {
1245                 debug("Error: allocating memory\n");
1246                 count = -ENOMEM;
1247                 goto exit;
1248         }
1249
1250         /* duplicate fsdata */
1251         fat_itr_child(dirs, itr);
1252         fsdata = *dirs->fsdata;
1253
1254         /* allocate local fat buffer */
1255         fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
1256         if (!fsdata.fatbuf) {
1257                 debug("Error: allocating memory\n");
1258                 count = -ENOMEM;
1259                 goto exit;
1260         }
1261         fsdata.fatbufnum = -1;
1262         dirs->fsdata = &fsdata;
1263
1264         for (count = 0; fat_itr_next(dirs); count++)
1265                 ;
1266
1267 exit:
1268         free(fsdata.fatbuf);
1269         free(dirs);
1270         return count;
1271 }
1272
1273 static int delete_dentry(fat_itr *itr)
1274 {
1275         fsdata *mydata = itr->fsdata;
1276         dir_entry *dentptr = itr->dent;
1277
1278         /* free cluster blocks */
1279         clear_fatent(mydata, START(dentptr));
1280         if (flush_dirty_fat_buffer(mydata) < 0) {
1281                 printf("Error: flush fat buffer\n");
1282                 return -EIO;
1283         }
1284
1285         /*
1286          * update a directory entry
1287          * TODO:
1288          *  - long file name support
1289          *  - find and mark the "new" first invalid entry as name[0]=0x00
1290          */
1291         memset(dentptr, 0, sizeof(*dentptr));
1292         dentptr->name[0] = 0xe5;
1293
1294         if (flush_dir(itr)) {
1295                 printf("error: writing directory entry\n");
1296                 return -EIO;
1297         }
1298
1299         return 0;
1300 }
1301
1302 int fat_unlink(const char *filename)
1303 {
1304         fsdata fsdata = { .fatbuf = NULL, };
1305         fat_itr *itr = NULL;
1306         int n_entries, ret;
1307         char *filename_copy, *dirname, *basename;
1308
1309         filename_copy = strdup(filename);
1310         if (!filename_copy) {
1311                 printf("Error: allocating memory\n");
1312                 ret = -ENOMEM;
1313                 goto exit;
1314         }
1315         split_filename(filename_copy, &dirname, &basename);
1316
1317         if (!strcmp(dirname, "/") && !strcmp(basename, "")) {
1318                 printf("Error: cannot remove root\n");
1319                 ret = -EINVAL;
1320                 goto exit;
1321         }
1322
1323         itr = malloc_cache_aligned(sizeof(fat_itr));
1324         if (!itr) {
1325                 printf("Error: allocating memory\n");
1326                 ret = -ENOMEM;
1327                 goto exit;
1328         }
1329
1330         ret = fat_itr_root(itr, &fsdata);
1331         if (ret)
1332                 goto exit;
1333
1334         total_sector = fsdata.total_sect;
1335
1336         ret = fat_itr_resolve(itr, dirname, TYPE_DIR);
1337         if (ret) {
1338                 printf("%s: doesn't exist (%d)\n", dirname, ret);
1339                 ret = -ENOENT;
1340                 goto exit;
1341         }
1342
1343         if (!find_directory_entry(itr, basename)) {
1344                 printf("%s: doesn't exist\n", basename);
1345                 ret = -ENOENT;
1346                 goto exit;
1347         }
1348
1349         if (fat_itr_isdir(itr)) {
1350                 n_entries = fat_dir_entries(itr);
1351                 if (n_entries < 0) {
1352                         ret = n_entries;
1353                         goto exit;
1354                 }
1355                 if (n_entries > 2) {
1356                         printf("Error: directory is not empty: %d\n",
1357                                n_entries);
1358                         ret = -EINVAL;
1359                         goto exit;
1360                 }
1361         }
1362
1363         ret = delete_dentry(itr);
1364
1365 exit:
1366         free(fsdata.fatbuf);
1367         free(itr);
1368         free(filename_copy);
1369
1370         return ret;
1371 }
1372
1373 int fat_mkdir(const char *new_dirname)
1374 {
1375         dir_entry *retdent;
1376         fsdata datablock = { .fatbuf = NULL, };
1377         fsdata *mydata = &datablock;
1378         fat_itr *itr = NULL;
1379         char *dirname_copy, *parent, *dirname;
1380         char l_dirname[VFAT_MAXLEN_BYTES];
1381         int ret = -1;
1382         loff_t actwrite;
1383         unsigned int bytesperclust;
1384         dir_entry *dotdent = NULL;
1385
1386         dirname_copy = strdup(new_dirname);
1387         if (!dirname_copy)
1388                 goto exit;
1389
1390         split_filename(dirname_copy, &parent, &dirname);
1391         if (!strlen(dirname)) {
1392                 ret = -EINVAL;
1393                 goto exit;
1394         }
1395
1396         if (normalize_longname(l_dirname, dirname)) {
1397                 printf("FAT: illegal filename (%s)\n", dirname);
1398                 ret = -EINVAL;
1399                 goto exit;
1400         }
1401
1402         itr = malloc_cache_aligned(sizeof(fat_itr));
1403         if (!itr) {
1404                 ret = -ENOMEM;
1405                 goto exit;
1406         }
1407
1408         ret = fat_itr_root(itr, &datablock);
1409         if (ret)
1410                 goto exit;
1411
1412         total_sector = datablock.total_sect;
1413
1414         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1415         if (ret) {
1416                 printf("%s: doesn't exist (%d)\n", parent, ret);
1417                 goto exit;
1418         }
1419
1420         retdent = find_directory_entry(itr, l_dirname);
1421
1422         if (retdent) {
1423                 printf("%s: already exists\n", l_dirname);
1424                 ret = -EEXIST;
1425                 goto exit;
1426         } else {
1427                 if (itr->is_root) {
1428                         /* root dir cannot have "." or ".." */
1429                         if (!strcmp(l_dirname, ".") ||
1430                             !strcmp(l_dirname, "..")) {
1431                                 ret = -EINVAL;
1432                                 goto exit;
1433                         }
1434                 }
1435
1436                 if (!itr->dent) {
1437                         printf("Error: allocating new dir entry\n");
1438                         ret = -EIO;
1439                         goto exit;
1440                 }
1441
1442                 memset(itr->dent, 0, sizeof(*itr->dent));
1443
1444                 /* Set short name to set alias checksum field in dir_slot */
1445                 set_name(itr->dent, dirname);
1446                 fill_dir_slot(itr, dirname);
1447
1448                 /* Set attribute as archive for regular file */
1449                 fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0,
1450                             ATTR_DIR | ATTR_ARCH);
1451
1452                 retdent = itr->dent;
1453         }
1454
1455         /* Default entries */
1456         bytesperclust = mydata->clust_size * mydata->sect_size;
1457         dotdent = malloc_cache_aligned(bytesperclust);
1458         if (!dotdent) {
1459                 ret = -ENOMEM;
1460                 goto exit;
1461         }
1462         memset(dotdent, 0, bytesperclust);
1463
1464         memcpy(dotdent[0].name, ".       ", 8);
1465         memcpy(dotdent[0].ext, "   ", 3);
1466         dotdent[0].attr = ATTR_DIR | ATTR_ARCH;
1467
1468         memcpy(dotdent[1].name, "..      ", 8);
1469         memcpy(dotdent[1].ext, "   ", 3);
1470         dotdent[1].attr = ATTR_DIR | ATTR_ARCH;
1471         set_start_cluster(mydata, &dotdent[1], itr->start_clust);
1472
1473         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1474                            bytesperclust, &actwrite);
1475         if (ret < 0) {
1476                 printf("Error: writing contents\n");
1477                 goto exit;
1478         }
1479         /* Write twice for "." */
1480         set_start_cluster(mydata, &dotdent[0], START(retdent));
1481         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1482                            bytesperclust, &actwrite);
1483         if (ret < 0) {
1484                 printf("Error: writing contents\n");
1485                 goto exit;
1486         }
1487
1488         /* Flush fat buffer */
1489         ret = flush_dirty_fat_buffer(mydata);
1490         if (ret) {
1491                 printf("Error: flush fat buffer\n");
1492                 goto exit;
1493         }
1494
1495         /* Write directory table to device */
1496         ret = flush_dir(itr);
1497         if (ret)
1498                 printf("Error: writing directory entry\n");
1499
1500 exit:
1501         free(dirname_copy);
1502         free(mydata->fatbuf);
1503         free(itr);
1504         free(dotdent);
1505         return ret;
1506 }