fs/fat/fat_write.c

   1 /*
   2  * fat_write.c
   3  *
   4  * R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <command.h>
  11 #include <config.h>
  12 #include <fat.h>
  13 #include <asm/byteorder.h>
  14 #include <part.h>
  15 #include <linux/ctype.h>
  16 #include "fat.c"
  17
  18 static void uppercase(char *str, int len)
  19 {
  20         int i;
  21
  22         for (i = 0; i < len; i++) {
  23                 *str = toupper(*str);
  24                 str++;
  25         }
  26 }
  27
  28 static int total_sector;
  29 static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
  30 {
  31         if (!cur_dev || !cur_dev->block_write)
  32                 return -1;
  33
  34         if (cur_part_info.start + block + nr_blocks >
  35                 cur_part_info.start + total_sector) {
  36                 printf("error: overflow occurs\n");
  37                 return -1;
  38         }
  39
  40         return cur_dev->block_write(cur_dev->dev,
  41                         cur_part_info.start + block, nr_blocks, buf);
  42 }
  43
  44 /*
  45  * Set short name in directory entry
  46  */
  47 static void set_name(dir_entry *dirent, const char *filename)
  48 {
  49         char s_name[VFAT_MAXLEN_BYTES];
  50         char *period;
  51         int period_location, len, i, ext_num;
  52
  53         if (filename == NULL)
  54                 return;
  55
  56         len = strlen(filename);
  57         if (len == 0)
  58                 return;
  59
  60         strcpy(s_name, filename);
  61         uppercase(s_name, len);
  62
  63         period = strchr(s_name, '.');
  64         if (period == NULL) {
  65                 period_location = len;
  66                 ext_num = 0;
  67         } else {
  68                 period_location = period - s_name;
  69                 ext_num = len - period_location - 1;
  70         }
  71
  72         /* Pad spaces when the length of file name is shorter than eight */
  73         if (period_location < 8) {
  74                 memcpy(dirent->name, s_name, period_location);
  75                 for (i = period_location; i < 8; i++)
  76                         dirent->name[i] = ' ';
  77         } else if (period_location == 8) {
  78                 memcpy(dirent->name, s_name, period_location);
  79         } else {
  80                 memcpy(dirent->name, s_name, 6);
  81                 dirent->name[6] = '~';
  82                 dirent->name[7] = '1';
  83         }
  84
  85         if (ext_num < 3) {
  86                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
  87                 for (i = ext_num; i < 3; i++)
  88                         dirent->ext[i] = ' ';
  89         } else
  90                 memcpy(dirent->ext, s_name + period_location + 1, 3);
  91
  92         debug("name : %s\n", dirent->name);
  93         debug("ext : %s\n", dirent->ext);
  94 }
  95
  96 static __u8 num_of_fats;
  97 /*
  98  * Write fat buffer into block device
  99  */
 100 static int flush_fat_buffer(fsdata *mydata)
 101 {
 102         int getsize = FATBUFBLOCKS;
 103         __u32 fatlength = mydata->fatlength;
 104         __u8 *bufptr = mydata->fatbuf;
 105         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 106
 107         startblock += mydata->fat_sect;
 108
 109         if (getsize > fatlength)
 110                 getsize = fatlength;
 111
 112         /* Write FAT buf */
 113         if (disk_write(startblock, getsize, bufptr) < 0) {
 114                 debug("error: writing FAT blocks\n");
 115                 return -1;
 116         }
 117
 118         if (num_of_fats == 2) {
 119                 /* Update corresponding second FAT blocks */
 120                 startblock += mydata->fatlength;
 121                 if (disk_write(startblock, getsize, bufptr) < 0) {
 122                         debug("error: writing second FAT blocks\n");
 123                         return -1;
 124                 }
 125         }
 126
 127         return 0;
 128 }
 129
 130 /*
 131  * Get the entry at index 'entry' in a FAT (12/16/32) table.
 132  * On failure 0x00 is returned.
 133  * When bufnum is changed, write back the previous fatbuf to the disk.
 134  */
 135 static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
 136 {
 137         __u32 bufnum;
 138         __u32 off16, offset;
 139         __u32 ret = 0x00;
 140         __u16 val1, val2;
 141
 142         if (CHECK_CLUST(entry, mydata->fatsize)) {
 143                 printf("Error: Invalid FAT entry: 0x%08x\n", entry);
 144                 return ret;
 145         }
 146
 147         switch (mydata->fatsize) {
 148         case 32:
 149                 bufnum = entry / FAT32BUFSIZE;
 150                 offset = entry - bufnum * FAT32BUFSIZE;
 151                 break;
 152         case 16:
 153                 bufnum = entry / FAT16BUFSIZE;
 154                 offset = entry - bufnum * FAT16BUFSIZE;
 155                 break;
 156         case 12:
 157                 bufnum = entry / FAT12BUFSIZE;
 158                 offset = entry - bufnum * FAT12BUFSIZE;
 159                 break;
 160
 161         default:
 162                 /* Unsupported FAT size */
 163                 return ret;
 164         }
 165
 166         debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
 167                mydata->fatsize, entry, entry, offset, offset);
 168
 169         /* Read a new block of FAT entries into the cache. */
 170         if (bufnum != mydata->fatbufnum) {
 171                 int getsize = FATBUFBLOCKS;
 172                 __u8 *bufptr = mydata->fatbuf;
 173                 __u32 fatlength = mydata->fatlength;
 174                 __u32 startblock = bufnum * FATBUFBLOCKS;
 175
 176                 if (getsize > fatlength)
 177                         getsize = fatlength;
 178
 179                 fatlength *= mydata->sect_size; /* We want it in bytes now */
 180                 startblock += mydata->fat_sect; /* Offset from start of disk */
 181
 182                 /* Write back the fatbuf to the disk */
 183                 if (mydata->fatbufnum != -1) {
 184                         if (flush_fat_buffer(mydata) < 0)
 185                                 return -1;
 186                 }
 187
 188                 if (disk_read(startblock, getsize, bufptr) < 0) {
 189                         debug("Error reading FAT blocks\n");
 190                         return ret;
 191                 }
 192                 mydata->fatbufnum = bufnum;
 193         }
 194
 195         /* Get the actual entry from the table */
 196         switch (mydata->fatsize) {
 197         case 32:
 198                 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
 199                 break;
 200         case 16:
 201                 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
 202                 break;
 203         case 12:
 204                 off16 = (offset * 3) / 4;
 205
 206                 switch (offset & 0x3) {
 207                 case 0:
 208                         ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
 209                         ret &= 0xfff;
 210                         break;
 211                 case 1:
 212                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 213                         val1 &= 0xf000;
 214                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 215                         val2 &= 0x00ff;
 216                         ret = (val2 << 4) | (val1 >> 12);
 217                         break;
 218                 case 2:
 219                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 220                         val1 &= 0xff00;
 221                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 222                         val2 &= 0x000f;
 223                         ret = (val2 << 8) | (val1 >> 8);
 224                         break;
 225                 case 3:
 226                         ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 227                         ret = (ret & 0xfff0) >> 4;
 228                         break;
 229                 default:
 230                         break;
 231                 }
 232                 break;
 233         }
 234         debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
 235                mydata->fatsize, ret, entry, offset);
 236
 237         return ret;
 238 }
 239
 240 /*
 241  * Set the file name information from 'name' into 'slotptr',
 242  */
 243 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 244 {
 245         int j, end_idx = 0;
 246
 247         for (j = 0; j <= 8; j += 2) {
 248                 if (name[*idx] == 0x00) {
 249                         slotptr->name0_4[j] = 0;
 250                         slotptr->name0_4[j + 1] = 0;
 251                         end_idx++;
 252                         goto name0_4;
 253                 }
 254                 slotptr->name0_4[j] = name[*idx];
 255                 (*idx)++;
 256                 end_idx++;
 257         }
 258         for (j = 0; j <= 10; j += 2) {
 259                 if (name[*idx] == 0x00) {
 260                         slotptr->name5_10[j] = 0;
 261                         slotptr->name5_10[j + 1] = 0;
 262                         end_idx++;
 263                         goto name5_10;
 264                 }
 265                 slotptr->name5_10[j] = name[*idx];
 266                 (*idx)++;
 267                 end_idx++;
 268         }
 269         for (j = 0; j <= 2; j += 2) {
 270                 if (name[*idx] == 0x00) {
 271                         slotptr->name11_12[j] = 0;
 272                         slotptr->name11_12[j + 1] = 0;
 273                         end_idx++;
 274                         goto name11_12;
 275                 }
 276                 slotptr->name11_12[j] = name[*idx];
 277                 (*idx)++;
 278                 end_idx++;
 279         }
 280
 281         if (name[*idx] == 0x00)
 282                 return 1;
 283
 284         return 0;
 285 /* Not used characters are filled with 0xff 0xff */
 286 name0_4:
 287         for (; end_idx < 5; end_idx++) {
 288                 slotptr->name0_4[end_idx * 2] = 0xff;
 289                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 290         }
 291         end_idx = 5;
 292 name5_10:
 293         end_idx -= 5;
 294         for (; end_idx < 6; end_idx++) {
 295                 slotptr->name5_10[end_idx * 2] = 0xff;
 296                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 297         }
 298         end_idx = 11;
 299 name11_12:
 300         end_idx -= 11;
 301         for (; end_idx < 2; end_idx++) {
 302                 slotptr->name11_12[end_idx * 2] = 0xff;
 303                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 304         }
 305
 306         return 1;
 307 }
 308
 309 static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
 310 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
 311
 312 /*
 313  * Fill dir_slot entries with appropriate name, id, and attr
 314  * The real directory entry is returned by 'dentptr'
 315  */
 316 static void
 317 fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
 318 {
 319         dir_slot *slotptr = (dir_slot *)get_contents_vfatname_block;
 320         __u8 counter = 0, checksum;
 321         int idx = 0, ret;
 322         char s_name[16];
 323
 324         /* Get short file name and checksum value */
 325         strncpy(s_name, (*dentptr)->name, 16);
 326         checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
 327
 328         do {
 329                 memset(slotptr, 0x00, sizeof(dir_slot));
 330                 ret = str2slot(slotptr, l_name, &idx);
 331                 slotptr->id = ++counter;
 332                 slotptr->attr = ATTR_VFAT;
 333                 slotptr->alias_checksum = checksum;
 334                 slotptr++;
 335         } while (ret == 0);
 336
 337         slotptr--;
 338         slotptr->id |= LAST_LONG_ENTRY_MASK;
 339
 340         while (counter >= 1) {
 341                 if (is_next_clust(mydata, *dentptr)) {
 342                         /* A new cluster is allocated for directory table */
 343                         flush_dir_table(mydata, dentptr);
 344                 }
 345                 memcpy(*dentptr, slotptr, sizeof(dir_slot));
 346                 (*dentptr)++;
 347                 slotptr--;
 348                 counter--;
 349         }
 350
 351         if (is_next_clust(mydata, *dentptr)) {
 352                 /* A new cluster is allocated for directory table */
 353                 flush_dir_table(mydata, dentptr);
 354         }
 355 }
 356
 357 static __u32 dir_curclust;
 358
 359 /*
 360  * Extract the full long filename starting at 'retdent' (which is really
 361  * a slot) into 'l_name'. If successful also copy the real directory entry
 362  * into 'retdent'
 363  * If additional adjacent cluster for directory entries is read into memory,
 364  * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
 365  * the location of the real directory entry is returned by 'retdent'
 366  * Return 0 on success, -1 otherwise.
 367  */
 368 static int
 369 get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
 370               dir_entry **retdent, char *l_name)
 371 {
 372         dir_entry *realdent;
 373         dir_slot *slotptr = (dir_slot *)(*retdent);
 374         dir_slot *slotptr2 = NULL;
 375         __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
 376                                                         PREFETCH_BLOCKS :
 377                                                         mydata->clust_size);
 378         __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
 379         int idx = 0, cur_position = 0;
 380
 381         if (counter > VFAT_MAXSEQ) {
 382                 debug("Error: VFAT name is too long\n");
 383                 return -1;
 384         }
 385
 386         while ((__u8 *)slotptr < buflimit) {
 387                 if (counter == 0)
 388                         break;
 389                 if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
 390                         return -1;
 391                 slotptr++;
 392                 counter--;
 393         }
 394
 395         if ((__u8 *)slotptr >= buflimit) {
 396                 if (curclust == 0)
 397                         return -1;
 398                 curclust = get_fatent_value(mydata, dir_curclust);
 399                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 400                         debug("curclust: 0x%x\n", curclust);
 401                         printf("Invalid FAT entry\n");
 402                         return -1;
 403                 }
 404
 405                 dir_curclust = curclust;
 406
 407                 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
 408                                 mydata->clust_size * mydata->sect_size) != 0) {
 409                         debug("Error: reading directory block\n");
 410                         return -1;
 411                 }
 412
 413                 slotptr2 = (dir_slot *)get_contents_vfatname_block;
 414                 while (counter > 0) {
 415                         if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
 416                             & 0xff) != counter)
 417                                 return -1;
 418                         slotptr2++;
 419                         counter--;
 420                 }
 421
 422                 /* Save the real directory entry */
 423                 realdent = (dir_entry *)slotptr2;
 424                 while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
 425                         slotptr2--;
 426                         slot2str(slotptr2, l_name, &idx);
 427                 }
 428         } else {
 429                 /* Save the real directory entry */
 430                 realdent = (dir_entry *)slotptr;
 431         }
 432
 433         do {
 434                 slotptr--;
 435                 if (slot2str(slotptr, l_name, &idx))
 436                         break;
 437         } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
 438
 439         l_name[idx] = '\0';
 440         if (*l_name == DELETED_FLAG)
 441                 *l_name = '\0';
 442         else if (*l_name == aRING)
 443                 *l_name = DELETED_FLAG;
 444         downcase(l_name);
 445
 446         /* Return the real directory entry */
 447         *retdent = realdent;
 448
 449         if (slotptr2) {
 450                 memcpy(get_dentfromdir_block, get_contents_vfatname_block,
 451                         mydata->clust_size * mydata->sect_size);
 452                 cur_position = (__u8 *)realdent - get_contents_vfatname_block;
 453                 *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
 454         }
 455
 456         return 0;
 457 }
 458
 459 /*
 460  * Set the entry at index 'entry' in a FAT (16/32) table.
 461  */
 462 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 463 {
 464         __u32 bufnum, offset;
 465
 466         switch (mydata->fatsize) {
 467         case 32:
 468                 bufnum = entry / FAT32BUFSIZE;
 469                 offset = entry - bufnum * FAT32BUFSIZE;
 470                 break;
 471         case 16:
 472                 bufnum = entry / FAT16BUFSIZE;
 473                 offset = entry - bufnum * FAT16BUFSIZE;
 474                 break;
 475         default:
 476                 /* Unsupported FAT size */
 477                 return -1;
 478         }
 479
 480         /* Read a new block of FAT entries into the cache. */
 481         if (bufnum != mydata->fatbufnum) {
 482                 int getsize = FATBUFBLOCKS;
 483                 __u8 *bufptr = mydata->fatbuf;
 484                 __u32 fatlength = mydata->fatlength;
 485                 __u32 startblock = bufnum * FATBUFBLOCKS;
 486
 487                 fatlength *= mydata->sect_size;
 488                 startblock += mydata->fat_sect;
 489
 490                 if (getsize > fatlength)
 491                         getsize = fatlength;
 492
 493                 if (mydata->fatbufnum != -1) {
 494                         if (flush_fat_buffer(mydata) < 0)
 495                                 return -1;
 496                 }
 497
 498                 if (disk_read(startblock, getsize, bufptr) < 0) {
 499                         debug("Error reading FAT blocks\n");
 500                         return -1;
 501                 }
 502                 mydata->fatbufnum = bufnum;
 503         }
 504
 505         /* Set the actual entry */
 506         switch (mydata->fatsize) {
 507         case 32:
 508                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 509                 break;
 510         case 16:
 511                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 512                 break;
 513         default:
 514                 return -1;
 515         }
 516
 517         return 0;
 518 }
 519
 520 /*
 521  * Determine the entry value at index 'entry' in a FAT (16/32) table
 522  */
 523 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 524 {
 525         __u32 next_fat, next_entry = entry + 1;
 526
 527         while (1) {
 528                 next_fat = get_fatent_value(mydata, next_entry);
 529                 if (next_fat == 0) {
 530                         set_fatent_value(mydata, entry, next_entry);
 531                         break;
 532                 }
 533                 next_entry++;
 534         }
 535         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 536                mydata->fatsize, entry, next_entry);
 537
 538         return next_entry;
 539 }
 540
 541 /*
 542  * Write at most 'size' bytes from 'buffer' into the specified cluster.
 543  * Return 0 on success, -1 otherwise.
 544  */
 545 static int
 546 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 547              unsigned long size)
 548 {
 549         int idx = 0;
 550         __u32 startsect;
 551
 552         if (clustnum > 0)
 553                 startsect = mydata->data_begin +
 554                                 clustnum * mydata->clust_size;
 555         else
 556                 startsect = mydata->rootdir_sect;
 557
 558         debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 559
 560         if ((size / mydata->sect_size) > 0) {
 561                 if (disk_write(startsect, size / mydata->sect_size, buffer) < 0) {
 562                         debug("Error writing data\n");
 563                         return -1;
 564                 }
 565         }
 566
 567         if (size % mydata->sect_size) {
 568                 __u8 tmpbuf[mydata->sect_size];
 569
 570                 idx = size / mydata->sect_size;
 571                 buffer += idx * mydata->sect_size;
 572                 memcpy(tmpbuf, buffer, size % mydata->sect_size);
 573
 574                 if (disk_write(startsect + idx, 1, tmpbuf) < 0) {
 575                         debug("Error writing data\n");
 576                         return -1;
 577                 }
 578
 579                 return 0;
 580         }
 581
 582         return 0;
 583 }
 584
 585 /*
 586  * Find the first empty cluster
 587  */
 588 static int find_empty_cluster(fsdata *mydata)
 589 {
 590         __u32 fat_val, entry = 3;
 591
 592         while (1) {
 593                 fat_val = get_fatent_value(mydata, entry);
 594                 if (fat_val == 0)
 595                         break;
 596                 entry++;
 597         }
 598
 599         return entry;
 600 }
 601
 602 /*
 603  * Write directory entries in 'get_dentfromdir_block' to block device
 604  */
 605 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
 606 {
 607         int dir_newclust = 0;
 608
 609         if (set_cluster(mydata, dir_curclust,
 610                     get_dentfromdir_block,
 611                     mydata->clust_size * mydata->sect_size) != 0) {
 612                 printf("error: wrinting directory entry\n");
 613                 return;
 614         }
 615         dir_newclust = find_empty_cluster(mydata);
 616         set_fatent_value(mydata, dir_curclust, dir_newclust);
 617         if (mydata->fatsize == 32)
 618                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 619         else if (mydata->fatsize == 16)
 620                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 621
 622         dir_curclust = dir_newclust;
 623
 624         if (flush_fat_buffer(mydata) < 0)
 625                 return;
 626
 627         memset(get_dentfromdir_block, 0x00,
 628                 mydata->clust_size * mydata->sect_size);
 629
 630         *dentptr = (dir_entry *) get_dentfromdir_block;
 631 }
 632
 633 /*
 634  * Set empty cluster from 'entry' to the end of a file
 635  */
 636 static int clear_fatent(fsdata *mydata, __u32 entry)
 637 {
 638         __u32 fat_val;
 639
 640         while (1) {
 641                 fat_val = get_fatent_value(mydata, entry);
 642                 if (fat_val != 0)
 643                         set_fatent_value(mydata, entry, 0);
 644                 else
 645                         break;
 646
 647                 if (fat_val == 0xfffffff || fat_val == 0xffff)
 648                         break;
 649
 650                 entry = fat_val;
 651         }
 652
 653         /* Flush fat buffer */
 654         if (flush_fat_buffer(mydata) < 0)
 655                 return -1;
 656
 657         return 0;
 658 }
 659
 660 /*
 661  * Write at most 'maxsize' bytes from 'buffer' into
 662  * the file associated with 'dentptr'
 663  * Return the number of bytes read or -1 on fatal errors.
 664  */
 665 static int
 666 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
 667               unsigned long maxsize)
 668 {
 669         unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
 670         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 671         __u32 curclust = START(dentptr);
 672         __u32 endclust = 0, newclust = 0;
 673         unsigned long actsize;
 674
 675         debug("Filesize: %ld bytes\n", filesize);
 676
 677         if (maxsize > 0 && filesize > maxsize)
 678                 filesize = maxsize;
 679
 680         debug("%ld bytes\n", filesize);
 681
 682         actsize = bytesperclust;
 683         endclust = curclust;
 684         do {
 685                 /* search for consecutive clusters */
 686                 while (actsize < filesize) {
 687                         newclust = determine_fatent(mydata, endclust);
 688
 689                         if ((newclust - 1) != endclust)
 690                                 goto getit;
 691
 692                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 693                                 debug("curclust: 0x%x\n", newclust);
 694                                 debug("Invalid FAT entry\n");
 695                                 return gotsize;
 696                         }
 697                         endclust = newclust;
 698                         actsize += bytesperclust;
 699                 }
 700                 /* actsize >= file size */
 701                 actsize -= bytesperclust;
 702                 /* set remaining clusters */
 703                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 704                         debug("error: writing cluster\n");
 705                         return -1;
 706                 }
 707
 708                 /* set remaining bytes */
 709                 gotsize += (int)actsize;
 710                 filesize -= actsize;
 711                 buffer += actsize;
 712                 actsize = filesize;
 713
 714                 if (set_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
 715                         debug("error: writing cluster\n");
 716                         return -1;
 717                 }
 718                 gotsize += actsize;
 719
 720                 /* Mark end of file in FAT */
 721                 if (mydata->fatsize == 16)
 722                         newclust = 0xffff;
 723                 else if (mydata->fatsize == 32)
 724                         newclust = 0xfffffff;
 725                 set_fatent_value(mydata, endclust, newclust);
 726
 727                 return gotsize;
 728 getit:
 729                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 730                         debug("error: writing cluster\n");
 731                         return -1;
 732                 }
 733                 gotsize += (int)actsize;
 734                 filesize -= actsize;
 735                 buffer += actsize;
 736
 737                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 738                         debug("curclust: 0x%x\n", curclust);
 739                         debug("Invalid FAT entry\n");
 740                         return gotsize;
 741                 }
 742                 actsize = bytesperclust;
 743                 curclust = endclust = newclust;
 744         } while (1);
 745 }
 746
 747 /*
 748  * Fill dir_entry
 749  */
 750 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 751         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 752 {
 753         if (mydata->fatsize == 32)
 754                 dentptr->starthi =
 755                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 756         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 757         dentptr->size = cpu_to_le32(size);
 758
 759         dentptr->attr = attr;
 760
 761         set_name(dentptr, filename);
 762 }
 763
 764 /*
 765  * Check whether adding a file makes the file system to
 766  * exceed the size of the block device
 767  * Return -1 when overflow occurs, otherwise return 0
 768  */
 769 static int check_overflow(fsdata *mydata, __u32 clustnum, unsigned long size)
 770 {
 771         __u32 startsect, sect_num;
 772
 773         if (clustnum > 0) {
 774                 startsect = mydata->data_begin +
 775                                 clustnum * mydata->clust_size;
 776         } else {
 777                 startsect = mydata->rootdir_sect;
 778         }
 779
 780         sect_num = size / mydata->sect_size;
 781         if (size % mydata->sect_size)
 782                 sect_num++;
 783
 784         if (startsect + sect_num > cur_part_info.start + total_sector)
 785                 return -1;
 786
 787         return 0;
 788 }
 789
 790 /*
 791  * Check if adding several entries exceed one cluster boundary
 792  */
 793 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
 794 {
 795         int cur_position;
 796
 797         cur_position = (__u8 *)dentptr - get_dentfromdir_block;
 798
 799         if (cur_position >= mydata->clust_size * mydata->sect_size)
 800                 return 1;
 801         else
 802                 return 0;
 803 }
 804
 805 static dir_entry *empty_dentptr;
 806 /*
 807  * Find a directory entry based on filename or start cluster number
 808  * If the directory entry is not found,
 809  * the new position for writing a directory entry will be returned
 810  */
 811 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
 812         char *filename, dir_entry *retdent, __u32 start)
 813 {
 814         __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
 815
 816         debug("get_dentfromdir: %s\n", filename);
 817
 818         while (1) {
 819                 dir_entry *dentptr;
 820
 821                 int i;
 822
 823                 if (get_cluster(mydata, curclust, get_dentfromdir_block,
 824                             mydata->clust_size * mydata->sect_size) != 0) {
 825                         printf("Error: reading directory block\n");
 826                         return NULL;
 827                 }
 828
 829                 dentptr = (dir_entry *)get_dentfromdir_block;
 830
 831                 dir_curclust = curclust;
 832
 833                 for (i = 0; i < DIRENTSPERCLUST; i++) {
 834                         char s_name[14], l_name[VFAT_MAXLEN_BYTES];
 835
 836                         l_name[0] = '\0';
 837                         if (dentptr->name[0] == DELETED_FLAG) {
 838                                 dentptr++;
 839                                 if (is_next_clust(mydata, dentptr))
 840                                         break;
 841                                 continue;
 842                         }
 843                         if ((dentptr->attr & ATTR_VOLUME)) {
 844                                 if (vfat_enabled &&
 845                                     (dentptr->attr & ATTR_VFAT) &&
 846                                     (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
 847                                         get_long_file_name(mydata, curclust,
 848                                                      get_dentfromdir_block,
 849                                                      &dentptr, l_name);
 850                                         debug("vfatname: |%s|\n", l_name);
 851                                 } else {
 852                                         /* Volume label or VFAT entry */
 853                                         dentptr++;
 854                                         if (is_next_clust(mydata, dentptr))
 855                                                 break;
 856                                         continue;
 857                                 }
 858                         }
 859                         if (dentptr->name[0] == 0) {
 860                                 debug("Dentname == NULL - %d\n", i);
 861                                 empty_dentptr = dentptr;
 862                                 return NULL;
 863                         }
 864
 865                         get_name(dentptr, s_name);
 866
 867                         if (strcmp(filename, s_name)
 868                             && strcmp(filename, l_name)) {
 869                                 debug("Mismatch: |%s|%s|\n",
 870                                         s_name, l_name);
 871                                 dentptr++;
 872                                 if (is_next_clust(mydata, dentptr))
 873                                         break;
 874                                 continue;
 875                         }
 876
 877                         memcpy(retdent, dentptr, sizeof(dir_entry));
 878
 879                         debug("DentName: %s", s_name);
 880                         debug(", start: 0x%x", START(dentptr));
 881                         debug(", size:  0x%x %s\n",
 882                               FAT2CPU32(dentptr->size),
 883                               (dentptr->attr & ATTR_DIR) ?
 884                               "(DIR)" : "");
 885
 886                         return dentptr;
 887                 }
 888
 889                 /*
 890                  * In FAT16/12, the root dir is locate before data area, shows
 891                  * in following:
 892                  * -------------------------------------------------------------
 893                  * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
 894                  * -------------------------------------------------------------
 895                  *
 896                  * As a result if curclust is in Root dir, it is a negative
 897                  * number or 0, 1.
 898                  *
 899                  */
 900                 if (mydata->fatsize != 32 && (int)curclust <= 1) {
 901                         /* Current clust is in root dir, set to next clust */
 902                         curclust++;
 903                         if ((int)curclust <= 1)
 904                                 continue;       /* continue to find */
 905
 906                         /* Reach the end of root dir */
 907                         empty_dentptr = dentptr;
 908                         return NULL;
 909                 }
 910
 911                 curclust = get_fatent_value(mydata, dir_curclust);
 912                 if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 913                         empty_dentptr = dentptr;
 914                         return NULL;
 915                 }
 916                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 917                         debug("curclust: 0x%x\n", curclust);
 918                         debug("Invalid FAT entry\n");
 919                         return NULL;
 920                 }
 921         }
 922
 923         return NULL;
 924 }
 925
 926 static int do_fat_write(const char *filename, void *buffer,
 927         unsigned long size)
 928 {
 929         dir_entry *dentptr, *retdent;
 930         __u32 startsect;
 931         __u32 start_cluster;
 932         boot_sector bs;
 933         volume_info volinfo;
 934         fsdata datablock;
 935         fsdata *mydata = &datablock;
 936         int cursect;
 937         int ret = -1, name_len;
 938         char l_filename[VFAT_MAXLEN_BYTES];
 939         int write_size = size;
 940
 941         dir_curclust = 0;
 942
 943         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 944                 debug("error: reading boot sector\n");
 945                 return -1;
 946         }
 947
 948         total_sector = bs.total_sect;
 949         if (total_sector == 0)
 950                 total_sector = cur_part_info.size;
 951
 952         if (mydata->fatsize == 32)
 953                 mydata->fatlength = bs.fat32_length;
 954         else
 955                 mydata->fatlength = bs.fat_length;
 956
 957         mydata->fat_sect = bs.reserved;
 958
 959         cursect = mydata->rootdir_sect
 960                 = mydata->fat_sect + mydata->fatlength * bs.fats;
 961         num_of_fats = bs.fats;
 962
 963         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
 964         mydata->clust_size = bs.cluster_size;
 965
 966         if (mydata->fatsize == 32) {
 967                 mydata->data_begin = mydata->rootdir_sect -
 968                                         (mydata->clust_size * 2);
 969         } else {
 970                 int rootdir_size;
 971
 972                 rootdir_size = ((bs.dir_entries[1]  * (int)256 +
 973                                  bs.dir_entries[0]) *
 974                                  sizeof(dir_entry)) /
 975                                  mydata->sect_size;
 976                 mydata->data_begin = mydata->rootdir_sect +
 977                                         rootdir_size -
 978                                         (mydata->clust_size * 2);
 979         }
 980
 981         mydata->fatbufnum = -1;
 982         mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
 983         if (mydata->fatbuf == NULL) {
 984                 debug("Error: allocating memory\n");
 985                 return -1;
 986         }
 987
 988         if (disk_read(cursect,
 989                 (mydata->fatsize == 32) ?
 990                 (mydata->clust_size) :
 991                 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
 992                 debug("Error: reading rootdir block\n");
 993                 goto exit;
 994         }
 995         dentptr = (dir_entry *) do_fat_read_at_block;
 996
 997         name_len = strlen(filename);
 998         if (name_len >= VFAT_MAXLEN_BYTES)
 999                 name_len = VFAT_MAXLEN_BYTES - 1;
1000
1001         memcpy(l_filename, filename, name_len);
1002         l_filename[name_len] = 0; /* terminate the string */
1003         downcase(l_filename);
1004
1005         startsect = mydata->rootdir_sect;
1006         retdent = find_directory_entry(mydata, startsect,
1007                                 l_filename, dentptr, 0);
1008         if (retdent) {
1009                 /* Update file size and start_cluster in a directory entry */
1010                 retdent->size = cpu_to_le32(size);
1011                 start_cluster = FAT2CPU16(retdent->start);
1012                 if (mydata->fatsize == 32)
1013                         start_cluster |=
1014                                 (FAT2CPU16(retdent->starthi) << 16);
1015
1016                 ret = check_overflow(mydata, start_cluster, size);
1017                 if (ret) {
1018                         printf("Error: %ld overflow\n", size);
1019                         goto exit;
1020                 }
1021
1022                 ret = clear_fatent(mydata, start_cluster);
1023                 if (ret) {
1024                         printf("Error: clearing FAT entries\n");
1025                         goto exit;
1026                 }
1027
1028                 ret = set_contents(mydata, retdent, buffer, size);
1029                 if (ret < 0) {
1030                         printf("Error: writing contents\n");
1031                         goto exit;
1032                 }
1033                 write_size = ret;
1034                 debug("attempt to write 0x%x bytes\n", write_size);
1035
1036                 /* Flush fat buffer */
1037                 ret = flush_fat_buffer(mydata);
1038                 if (ret) {
1039                         printf("Error: flush fat buffer\n");
1040                         goto exit;
1041                 }
1042
1043                 /* Write directory table to device */
1044                 ret = set_cluster(mydata, dir_curclust,
1045                             get_dentfromdir_block,
1046                             mydata->clust_size * mydata->sect_size);
1047                 if (ret) {
1048                         printf("Error: writing directory entry\n");
1049                         goto exit;
1050                 }
1051         } else {
1052                 /* Set short name to set alias checksum field in dir_slot */
1053                 set_name(empty_dentptr, filename);
1054                 fill_dir_slot(mydata, &empty_dentptr, filename);
1055
1056                 ret = start_cluster = find_empty_cluster(mydata);
1057                 if (ret < 0) {
1058                         printf("Error: finding empty cluster\n");
1059                         goto exit;
1060                 }
1061
1062                 ret = check_overflow(mydata, start_cluster, size);
1063                 if (ret) {
1064                         printf("Error: %ld overflow\n", size);
1065                         goto exit;
1066                 }
1067
1068                 /* Set attribute as archieve for regular file */
1069                 fill_dentry(mydata, empty_dentptr, filename,
1070                         start_cluster, size, 0x20);
1071
1072                 ret = set_contents(mydata, empty_dentptr, buffer, size);
1073                 if (ret < 0) {
1074                         printf("Error: writing contents\n");
1075                         goto exit;
1076                 }
1077                 write_size = ret;
1078                 debug("attempt to write 0x%x bytes\n", write_size);
1079
1080                 /* Flush fat buffer */
1081                 ret = flush_fat_buffer(mydata);
1082                 if (ret) {
1083                         printf("Error: flush fat buffer\n");
1084                         goto exit;
1085                 }
1086
1087                 /* Write directory table to device */
1088                 ret = set_cluster(mydata, dir_curclust,
1089                             get_dentfromdir_block,
1090                             mydata->clust_size * mydata->sect_size);
1091                 if (ret) {
1092                         printf("Error: writing directory entry\n");
1093                         goto exit;
1094                 }
1095         }
1096
1097 exit:
1098         free(mydata->fatbuf);
1099         return ret < 0 ? ret : write_size;
1100 }
1101
1102 int file_fat_write(const char *filename, void *buffer, unsigned long maxsize)
1103 {
1104         printf("writing %s\n", filename);
1105         return do_fat_write(filename, buffer, maxsize);
1106 }