git.sur5r.net Git - u-boot/blob - 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         memcpy(s_name, filename, len);
  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         switch (mydata->fatsize) {
 143         case 32:
 144                 bufnum = entry / FAT32BUFSIZE;
 145                 offset = entry - bufnum * FAT32BUFSIZE;
 146                 break;
 147         case 16:
 148                 bufnum = entry / FAT16BUFSIZE;
 149                 offset = entry - bufnum * FAT16BUFSIZE;
 150                 break;
 151         case 12:
 152                 bufnum = entry / FAT12BUFSIZE;
 153                 offset = entry - bufnum * FAT12BUFSIZE;
 154                 break;
 155
 156         default:
 157                 /* Unsupported FAT size */
 158                 return ret;
 159         }
 160
 161         debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
 162                mydata->fatsize, entry, entry, offset, offset);
 163
 164         /* Read a new block of FAT entries into the cache. */
 165         if (bufnum != mydata->fatbufnum) {
 166                 int getsize = FATBUFBLOCKS;
 167                 __u8 *bufptr = mydata->fatbuf;
 168                 __u32 fatlength = mydata->fatlength;
 169                 __u32 startblock = bufnum * FATBUFBLOCKS;
 170
 171                 if (getsize > fatlength)
 172                         getsize = fatlength;
 173
 174                 fatlength *= mydata->sect_size; /* We want it in bytes now */
 175                 startblock += mydata->fat_sect; /* Offset from start of disk */
 176
 177                 /* Write back the fatbuf to the disk */
 178                 if (mydata->fatbufnum != -1) {
 179                         if (flush_fat_buffer(mydata) < 0)
 180                                 return -1;
 181                 }
 182
 183                 if (disk_read(startblock, getsize, bufptr) < 0) {
 184                         debug("Error reading FAT blocks\n");
 185                         return ret;
 186                 }
 187                 mydata->fatbufnum = bufnum;
 188         }
 189
 190         /* Get the actual entry from the table */
 191         switch (mydata->fatsize) {
 192         case 32:
 193                 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
 194                 break;
 195         case 16:
 196                 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
 197                 break;
 198         case 12:
 199                 off16 = (offset * 3) / 4;
 200
 201                 switch (offset & 0x3) {
 202                 case 0:
 203                         ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
 204                         ret &= 0xfff;
 205                         break;
 206                 case 1:
 207                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 208                         val1 &= 0xf000;
 209                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 210                         val2 &= 0x00ff;
 211                         ret = (val2 << 4) | (val1 >> 12);
 212                         break;
 213                 case 2:
 214                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 215                         val1 &= 0xff00;
 216                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 217                         val2 &= 0x000f;
 218                         ret = (val2 << 8) | (val1 >> 8);
 219                         break;
 220                 case 3:
 221                         ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 222                         ret = (ret & 0xfff0) >> 4;
 223                         break;
 224                 default:
 225                         break;
 226                 }
 227                 break;
 228         }
 229         debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
 230                mydata->fatsize, ret, entry, offset);
 231
 232         return ret;
 233 }
 234
 235 /*
 236  * Set the file name information from 'name' into 'slotptr',
 237  */
 238 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 239 {
 240         int j, end_idx = 0;
 241
 242         for (j = 0; j <= 8; j += 2) {
 243                 if (name[*idx] == 0x00) {
 244                         slotptr->name0_4[j] = 0;
 245                         slotptr->name0_4[j + 1] = 0;
 246                         end_idx++;
 247                         goto name0_4;
 248                 }
 249                 slotptr->name0_4[j] = name[*idx];
 250                 (*idx)++;
 251                 end_idx++;
 252         }
 253         for (j = 0; j <= 10; j += 2) {
 254                 if (name[*idx] == 0x00) {
 255                         slotptr->name5_10[j] = 0;
 256                         slotptr->name5_10[j + 1] = 0;
 257                         end_idx++;
 258                         goto name5_10;
 259                 }
 260                 slotptr->name5_10[j] = name[*idx];
 261                 (*idx)++;
 262                 end_idx++;
 263         }
 264         for (j = 0; j <= 2; j += 2) {
 265                 if (name[*idx] == 0x00) {
 266                         slotptr->name11_12[j] = 0;
 267                         slotptr->name11_12[j + 1] = 0;
 268                         end_idx++;
 269                         goto name11_12;
 270                 }
 271                 slotptr->name11_12[j] = name[*idx];
 272                 (*idx)++;
 273                 end_idx++;
 274         }
 275
 276         if (name[*idx] == 0x00)
 277                 return 1;
 278
 279         return 0;
 280 /* Not used characters are filled with 0xff 0xff */
 281 name0_4:
 282         for (; end_idx < 5; end_idx++) {
 283                 slotptr->name0_4[end_idx * 2] = 0xff;
 284                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 285         }
 286         end_idx = 5;
 287 name5_10:
 288         end_idx -= 5;
 289         for (; end_idx < 6; end_idx++) {
 290                 slotptr->name5_10[end_idx * 2] = 0xff;
 291                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 292         }
 293         end_idx = 11;
 294 name11_12:
 295         end_idx -= 11;
 296         for (; end_idx < 2; end_idx++) {
 297                 slotptr->name11_12[end_idx * 2] = 0xff;
 298                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 299         }
 300
 301         return 1;
 302 }
 303
 304 static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
 305 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
 306
 307 /*
 308  * Fill dir_slot entries with appropriate name, id, and attr
 309  * The real directory entry is returned by 'dentptr'
 310  */
 311 static void
 312 fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
 313 {
 314         dir_slot *slotptr = (dir_slot *)get_contents_vfatname_block;
 315         __u8 counter = 0, checksum;
 316         int idx = 0, ret;
 317         char s_name[16];
 318
 319         /* Get short file name and checksum value */
 320         strncpy(s_name, (*dentptr)->name, 16);
 321         checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
 322
 323         do {
 324                 memset(slotptr, 0x00, sizeof(dir_slot));
 325                 ret = str2slot(slotptr, l_name, &idx);
 326                 slotptr->id = ++counter;
 327                 slotptr->attr = ATTR_VFAT;
 328                 slotptr->alias_checksum = checksum;
 329                 slotptr++;
 330         } while (ret == 0);
 331
 332         slotptr--;
 333         slotptr->id |= LAST_LONG_ENTRY_MASK;
 334
 335         while (counter >= 1) {
 336                 if (is_next_clust(mydata, *dentptr)) {
 337                         /* A new cluster is allocated for directory table */
 338                         flush_dir_table(mydata, dentptr);
 339                 }
 340                 memcpy(*dentptr, slotptr, sizeof(dir_slot));
 341                 (*dentptr)++;
 342                 slotptr--;
 343                 counter--;
 344         }
 345
 346         if (is_next_clust(mydata, *dentptr)) {
 347                 /* A new cluster is allocated for directory table */
 348                 flush_dir_table(mydata, dentptr);
 349         }
 350 }
 351
 352 static __u32 dir_curclust;
 353
 354 /*
 355  * Extract the full long filename starting at 'retdent' (which is really
 356  * a slot) into 'l_name'. If successful also copy the real directory entry
 357  * into 'retdent'
 358  * If additional adjacent cluster for directory entries is read into memory,
 359  * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
 360  * the location of the real directory entry is returned by 'retdent'
 361  * Return 0 on success, -1 otherwise.
 362  */
 363 static int
 364 get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
 365               dir_entry **retdent, char *l_name)
 366 {
 367         dir_entry *realdent;
 368         dir_slot *slotptr = (dir_slot *)(*retdent);
 369         dir_slot *slotptr2 = NULL;
 370         __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
 371                                                         PREFETCH_BLOCKS :
 372                                                         mydata->clust_size);
 373         __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
 374         int idx = 0, cur_position = 0;
 375
 376         if (counter > VFAT_MAXSEQ) {
 377                 debug("Error: VFAT name is too long\n");
 378                 return -1;
 379         }
 380
 381         while ((__u8 *)slotptr < buflimit) {
 382                 if (counter == 0)
 383                         break;
 384                 if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
 385                         return -1;
 386                 slotptr++;
 387                 counter--;
 388         }
 389
 390         if ((__u8 *)slotptr >= buflimit) {
 391                 if (curclust == 0)
 392                         return -1;
 393                 curclust = get_fatent_value(mydata, dir_curclust);
 394                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 395                         debug("curclust: 0x%x\n", curclust);
 396                         printf("Invalid FAT entry\n");
 397                         return -1;
 398                 }
 399
 400                 dir_curclust = curclust;
 401
 402                 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
 403                                 mydata->clust_size * mydata->sect_size) != 0) {
 404                         debug("Error: reading directory block\n");
 405                         return -1;
 406                 }
 407
 408                 slotptr2 = (dir_slot *)get_contents_vfatname_block;
 409                 while (counter > 0) {
 410                         if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
 411                             & 0xff) != counter)
 412                                 return -1;
 413                         slotptr2++;
 414                         counter--;
 415                 }
 416
 417                 /* Save the real directory entry */
 418                 realdent = (dir_entry *)slotptr2;
 419                 while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
 420                         slotptr2--;
 421                         slot2str(slotptr2, l_name, &idx);
 422                 }
 423         } else {
 424                 /* Save the real directory entry */
 425                 realdent = (dir_entry *)slotptr;
 426         }
 427
 428         do {
 429                 slotptr--;
 430                 if (slot2str(slotptr, l_name, &idx))
 431                         break;
 432         } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
 433
 434         l_name[idx] = '\0';
 435         if (*l_name == DELETED_FLAG)
 436                 *l_name = '\0';
 437         else if (*l_name == aRING)
 438                 *l_name = DELETED_FLAG;
 439         downcase(l_name);
 440
 441         /* Return the real directory entry */
 442         *retdent = realdent;
 443
 444         if (slotptr2) {
 445                 memcpy(get_dentfromdir_block, get_contents_vfatname_block,
 446                         mydata->clust_size * mydata->sect_size);
 447                 cur_position = (__u8 *)realdent - get_contents_vfatname_block;
 448                 *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
 449         }
 450
 451         return 0;
 452 }
 453
 454 /*
 455  * Set the entry at index 'entry' in a FAT (16/32) table.
 456  */
 457 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 458 {
 459         __u32 bufnum, offset;
 460
 461         switch (mydata->fatsize) {
 462         case 32:
 463                 bufnum = entry / FAT32BUFSIZE;
 464                 offset = entry - bufnum * FAT32BUFSIZE;
 465                 break;
 466         case 16:
 467                 bufnum = entry / FAT16BUFSIZE;
 468                 offset = entry - bufnum * FAT16BUFSIZE;
 469                 break;
 470         default:
 471                 /* Unsupported FAT size */
 472                 return -1;
 473         }
 474
 475         /* Read a new block of FAT entries into the cache. */
 476         if (bufnum != mydata->fatbufnum) {
 477                 int getsize = FATBUFBLOCKS;
 478                 __u8 *bufptr = mydata->fatbuf;
 479                 __u32 fatlength = mydata->fatlength;
 480                 __u32 startblock = bufnum * FATBUFBLOCKS;
 481
 482                 fatlength *= mydata->sect_size;
 483                 startblock += mydata->fat_sect;
 484
 485                 if (getsize > fatlength)
 486                         getsize = fatlength;
 487
 488                 if (mydata->fatbufnum != -1) {
 489                         if (flush_fat_buffer(mydata) < 0)
 490                                 return -1;
 491                 }
 492
 493                 if (disk_read(startblock, getsize, bufptr) < 0) {
 494                         debug("Error reading FAT blocks\n");
 495                         return -1;
 496                 }
 497                 mydata->fatbufnum = bufnum;
 498         }
 499
 500         /* Set the actual entry */
 501         switch (mydata->fatsize) {
 502         case 32:
 503                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 504                 break;
 505         case 16:
 506                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 507                 break;
 508         default:
 509                 return -1;
 510         }
 511
 512         return 0;
 513 }
 514
 515 /*
 516  * Determine the entry value at index 'entry' in a FAT (16/32) table
 517  */
 518 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 519 {
 520         __u32 next_fat, next_entry = entry + 1;
 521
 522         while (1) {
 523                 next_fat = get_fatent_value(mydata, next_entry);
 524                 if (next_fat == 0) {
 525                         set_fatent_value(mydata, entry, next_entry);
 526                         break;
 527                 }
 528                 next_entry++;
 529         }
 530         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 531                mydata->fatsize, entry, next_entry);
 532
 533         return next_entry;
 534 }
 535
 536 /*
 537  * Write at most 'size' bytes from 'buffer' into the specified cluster.
 538  * Return 0 on success, -1 otherwise.
 539  */
 540 static int
 541 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 542              unsigned long size)
 543 {
 544         int idx = 0;
 545         __u32 startsect;
 546
 547         if (clustnum > 0)
 548                 startsect = mydata->data_begin +
 549                                 clustnum * mydata->clust_size;
 550         else
 551                 startsect = mydata->rootdir_sect;
 552
 553         debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 554
 555         if (disk_write(startsect, size / mydata->sect_size, buffer) < 0) {
 556                 debug("Error writing data\n");
 557                 return -1;
 558         }
 559
 560         if (size % mydata->sect_size) {
 561                 __u8 tmpbuf[mydata->sect_size];
 562
 563                 idx = size / mydata->sect_size;
 564                 buffer += idx * mydata->sect_size;
 565                 memcpy(tmpbuf, buffer, size % mydata->sect_size);
 566
 567                 if (disk_write(startsect + idx, 1, tmpbuf) < 0) {
 568                         debug("Error writing data\n");
 569                         return -1;
 570                 }
 571
 572                 return 0;
 573         }
 574
 575         return 0;
 576 }
 577
 578 /*
 579  * Find the first empty cluster
 580  */
 581 static int find_empty_cluster(fsdata *mydata)
 582 {
 583         __u32 fat_val, entry = 3;
 584
 585         while (1) {
 586                 fat_val = get_fatent_value(mydata, entry);
 587                 if (fat_val == 0)
 588                         break;
 589                 entry++;
 590         }
 591
 592         return entry;
 593 }
 594
 595 /*
 596  * Write directory entries in 'get_dentfromdir_block' to block device
 597  */
 598 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
 599 {
 600         int dir_newclust = 0;
 601
 602         if (set_cluster(mydata, dir_curclust,
 603                     get_dentfromdir_block,
 604                     mydata->clust_size * mydata->sect_size) != 0) {
 605                 printf("error: wrinting directory entry\n");
 606                 return;
 607         }
 608         dir_newclust = find_empty_cluster(mydata);
 609         set_fatent_value(mydata, dir_curclust, dir_newclust);
 610         if (mydata->fatsize == 32)
 611                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 612         else if (mydata->fatsize == 16)
 613                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 614
 615         dir_curclust = dir_newclust;
 616
 617         if (flush_fat_buffer(mydata) < 0)
 618                 return;
 619
 620         memset(get_dentfromdir_block, 0x00,
 621                 mydata->clust_size * mydata->sect_size);
 622
 623         *dentptr = (dir_entry *) get_dentfromdir_block;
 624 }
 625
 626 /*
 627  * Set empty cluster from 'entry' to the end of a file
 628  */
 629 static int clear_fatent(fsdata *mydata, __u32 entry)
 630 {
 631         __u32 fat_val;
 632
 633         while (1) {
 634                 fat_val = get_fatent_value(mydata, entry);
 635                 if (fat_val != 0)
 636                         set_fatent_value(mydata, entry, 0);
 637                 else
 638                         break;
 639
 640                 if (fat_val == 0xfffffff || fat_val == 0xffff)
 641                         break;
 642
 643                 entry = fat_val;
 644         }
 645
 646         /* Flush fat buffer */
 647         if (flush_fat_buffer(mydata) < 0)
 648                 return -1;
 649
 650         return 0;
 651 }
 652
 653 /*
 654  * Write at most 'maxsize' bytes from 'buffer' into
 655  * the file associated with 'dentptr'
 656  * Return the number of bytes read or -1 on fatal errors.
 657  */
 658 static int
 659 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
 660               unsigned long maxsize)
 661 {
 662         unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
 663         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 664         __u32 curclust = START(dentptr);
 665         __u32 endclust = 0, newclust = 0;
 666         unsigned long actsize;
 667
 668         debug("Filesize: %ld bytes\n", filesize);
 669
 670         if (maxsize > 0 && filesize > maxsize)
 671                 filesize = maxsize;
 672
 673         debug("%ld bytes\n", filesize);
 674
 675         actsize = bytesperclust;
 676         endclust = curclust;
 677         do {
 678                 /* search for consecutive clusters */
 679                 while (actsize < filesize) {
 680                         newclust = determine_fatent(mydata, endclust);
 681
 682                         if ((newclust - 1) != endclust)
 683                                 goto getit;
 684
 685                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 686                                 debug("curclust: 0x%x\n", newclust);
 687                                 debug("Invalid FAT entry\n");
 688                                 return gotsize;
 689                         }
 690                         endclust = newclust;
 691                         actsize += bytesperclust;
 692                 }
 693                 /* actsize >= file size */
 694                 actsize -= bytesperclust;
 695                 /* set remaining clusters */
 696                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 697                         debug("error: writing cluster\n");
 698                         return -1;
 699                 }
 700
 701                 /* set remaining bytes */
 702                 gotsize += (int)actsize;
 703                 filesize -= actsize;
 704                 buffer += actsize;
 705                 actsize = filesize;
 706
 707                 if (set_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
 708                         debug("error: writing cluster\n");
 709                         return -1;
 710                 }
 711                 gotsize += actsize;
 712
 713                 /* Mark end of file in FAT */
 714                 if (mydata->fatsize == 16)
 715                         newclust = 0xffff;
 716                 else if (mydata->fatsize == 32)
 717                         newclust = 0xfffffff;
 718                 set_fatent_value(mydata, endclust, newclust);
 719
 720                 return gotsize;
 721 getit:
 722                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 723                         debug("error: writing cluster\n");
 724                         return -1;
 725                 }
 726                 gotsize += (int)actsize;
 727                 filesize -= actsize;
 728                 buffer += actsize;
 729
 730                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 731                         debug("curclust: 0x%x\n", curclust);
 732                         debug("Invalid FAT entry\n");
 733                         return gotsize;
 734                 }
 735                 actsize = bytesperclust;
 736                 curclust = endclust = newclust;
 737         } while (1);
 738 }
 739
 740 /*
 741  * Fill dir_entry
 742  */
 743 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 744         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 745 {
 746         if (mydata->fatsize == 32)
 747                 dentptr->starthi =
 748                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 749         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 750         dentptr->size = cpu_to_le32(size);
 751
 752         dentptr->attr = attr;
 753
 754         set_name(dentptr, filename);
 755 }
 756
 757 /*
 758  * Check whether adding a file makes the file system to
 759  * exceed the size of the block device
 760  * Return -1 when overflow occurs, otherwise return 0
 761  */
 762 static int check_overflow(fsdata *mydata, __u32 clustnum, unsigned long size)
 763 {
 764         __u32 startsect, sect_num;
 765
 766         if (clustnum > 0) {
 767                 startsect = mydata->data_begin +
 768                                 clustnum * mydata->clust_size;
 769         } else {
 770                 startsect = mydata->rootdir_sect;
 771         }
 772
 773         sect_num = size / mydata->sect_size;
 774         if (size % mydata->sect_size)
 775                 sect_num++;
 776
 777         if (startsect + sect_num > cur_part_info.start + total_sector)
 778                 return -1;
 779
 780         return 0;
 781 }
 782
 783 /*
 784  * Check if adding several entries exceed one cluster boundary
 785  */
 786 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
 787 {
 788         int cur_position;
 789
 790         cur_position = (__u8 *)dentptr - get_dentfromdir_block;
 791
 792         if (cur_position >= mydata->clust_size * mydata->sect_size)
 793                 return 1;
 794         else
 795                 return 0;
 796 }
 797
 798 static dir_entry *empty_dentptr;
 799 /*
 800  * Find a directory entry based on filename or start cluster number
 801  * If the directory entry is not found,
 802  * the new position for writing a directory entry will be returned
 803  */
 804 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
 805         char *filename, dir_entry *retdent, __u32 start)
 806 {
 807         __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
 808
 809         debug("get_dentfromdir: %s\n", filename);
 810
 811         while (1) {
 812                 dir_entry *dentptr;
 813
 814                 int i;
 815
 816                 if (get_cluster(mydata, curclust, get_dentfromdir_block,
 817                             mydata->clust_size * mydata->sect_size) != 0) {
 818                         printf("Error: reading directory block\n");
 819                         return NULL;
 820                 }
 821
 822                 dentptr = (dir_entry *)get_dentfromdir_block;
 823
 824                 dir_curclust = curclust;
 825
 826                 for (i = 0; i < DIRENTSPERCLUST; i++) {
 827                         char s_name[14], l_name[VFAT_MAXLEN_BYTES];
 828
 829                         l_name[0] = '\0';
 830                         if (dentptr->name[0] == DELETED_FLAG) {
 831                                 dentptr++;
 832                                 if (is_next_clust(mydata, dentptr))
 833                                         break;
 834                                 continue;
 835                         }
 836                         if ((dentptr->attr & ATTR_VOLUME)) {
 837                                 if (vfat_enabled &&
 838                                     (dentptr->attr & ATTR_VFAT) &&
 839                                     (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
 840                                         get_long_file_name(mydata, curclust,
 841                                                      get_dentfromdir_block,
 842                                                      &dentptr, l_name);
 843                                         debug("vfatname: |%s|\n", l_name);
 844                                 } else {
 845                                         /* Volume label or VFAT entry */
 846                                         dentptr++;
 847                                         if (is_next_clust(mydata, dentptr))
 848                                                 break;
 849                                         continue;
 850                                 }
 851                         }
 852                         if (dentptr->name[0] == 0) {
 853                                 debug("Dentname == NULL - %d\n", i);
 854                                 empty_dentptr = dentptr;
 855                                 return NULL;
 856                         }
 857
 858                         get_name(dentptr, s_name);
 859
 860                         if (strcmp(filename, s_name)
 861                             && strcmp(filename, l_name)) {
 862                                 debug("Mismatch: |%s|%s|\n",
 863                                         s_name, l_name);
 864                                 dentptr++;
 865                                 if (is_next_clust(mydata, dentptr))
 866                                         break;
 867                                 continue;
 868                         }
 869
 870                         memcpy(retdent, dentptr, sizeof(dir_entry));
 871
 872                         debug("DentName: %s", s_name);
 873                         debug(", start: 0x%x", START(dentptr));
 874                         debug(", size:  0x%x %s\n",
 875                               FAT2CPU32(dentptr->size),
 876                               (dentptr->attr & ATTR_DIR) ?
 877                               "(DIR)" : "");
 878
 879                         return dentptr;
 880                 }
 881
 882                 curclust = get_fatent_value(mydata, dir_curclust);
 883                 if ((curclust >= 0xffffff8) || (curclust >= 0xfff8)) {
 884                         empty_dentptr = dentptr;
 885                         return NULL;
 886                 }
 887                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 888                         debug("curclust: 0x%x\n", curclust);
 889                         debug("Invalid FAT entry\n");
 890                         return NULL;
 891                 }
 892         }
 893
 894         return NULL;
 895 }
 896
 897 static int do_fat_write(const char *filename, void *buffer,
 898         unsigned long size)
 899 {
 900         dir_entry *dentptr, *retdent;
 901         __u32 startsect;
 902         __u32 start_cluster;
 903         boot_sector bs;
 904         volume_info volinfo;
 905         fsdata datablock;
 906         fsdata *mydata = &datablock;
 907         int cursect;
 908         int ret = -1, name_len;
 909         char l_filename[VFAT_MAXLEN_BYTES];
 910         int write_size = size;
 911
 912         dir_curclust = 0;
 913
 914         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 915                 debug("error: reading boot sector\n");
 916                 return -1;
 917         }
 918
 919         total_sector = bs.total_sect;
 920         if (total_sector == 0)
 921                 total_sector = cur_part_info.size;
 922
 923         if (mydata->fatsize == 32)
 924                 mydata->fatlength = bs.fat32_length;
 925         else
 926                 mydata->fatlength = bs.fat_length;
 927
 928         mydata->fat_sect = bs.reserved;
 929
 930         cursect = mydata->rootdir_sect
 931                 = mydata->fat_sect + mydata->fatlength * bs.fats;
 932         num_of_fats = bs.fats;
 933
 934         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
 935         mydata->clust_size = bs.cluster_size;
 936
 937         if (mydata->fatsize == 32) {
 938                 mydata->data_begin = mydata->rootdir_sect -
 939                                         (mydata->clust_size * 2);
 940         } else {
 941                 int rootdir_size;
 942
 943                 rootdir_size = ((bs.dir_entries[1]  * (int)256 +
 944                                  bs.dir_entries[0]) *
 945                                  sizeof(dir_entry)) /
 946                                  mydata->sect_size;
 947                 mydata->data_begin = mydata->rootdir_sect +
 948                                         rootdir_size -
 949                                         (mydata->clust_size * 2);
 950         }
 951
 952         mydata->fatbufnum = -1;
 953         mydata->fatbuf = malloc(FATBUFSIZE);
 954         if (mydata->fatbuf == NULL) {
 955                 debug("Error: allocating memory\n");
 956                 return -1;
 957         }
 958
 959         if (disk_read(cursect,
 960                 (mydata->fatsize == 32) ?
 961                 (mydata->clust_size) :
 962                 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
 963                 debug("Error: reading rootdir block\n");
 964                 goto exit;
 965         }
 966         dentptr = (dir_entry *) do_fat_read_at_block;
 967
 968         name_len = strlen(filename);
 969         if (name_len >= VFAT_MAXLEN_BYTES)
 970                 name_len = VFAT_MAXLEN_BYTES - 1;
 971
 972         memcpy(l_filename, filename, name_len);
 973         l_filename[name_len] = 0; /* terminate the string */
 974         downcase(l_filename);
 975
 976         startsect = mydata->rootdir_sect;
 977         retdent = find_directory_entry(mydata, startsect,
 978                                 l_filename, dentptr, 0);
 979         if (retdent) {
 980                 /* Update file size and start_cluster in a directory entry */
 981                 retdent->size = cpu_to_le32(size);
 982                 start_cluster = FAT2CPU16(retdent->start);
 983                 if (mydata->fatsize == 32)
 984                         start_cluster |=
 985                                 (FAT2CPU16(retdent->starthi) << 16);
 986
 987                 ret = check_overflow(mydata, start_cluster, size);
 988                 if (ret) {
 989                         printf("Error: %ld overflow\n", size);
 990                         goto exit;
 991                 }
 992
 993                 ret = clear_fatent(mydata, start_cluster);
 994                 if (ret) {
 995                         printf("Error: clearing FAT entries\n");
 996                         goto exit;
 997                 }
 998
 999                 ret = set_contents(mydata, retdent, buffer, size);
1000                 if (ret < 0) {
1001                         printf("Error: writing contents\n");
1002                         goto exit;
1003                 }
1004                 write_size = ret;
1005                 debug("attempt to write 0x%x bytes\n", write_size);
1006
1007                 /* Flush fat buffer */
1008                 ret = flush_fat_buffer(mydata);
1009                 if (ret) {
1010                         printf("Error: flush fat buffer\n");
1011                         goto exit;
1012                 }
1013
1014                 /* Write directory table to device */
1015                 ret = set_cluster(mydata, dir_curclust,
1016                             get_dentfromdir_block,
1017                             mydata->clust_size * mydata->sect_size);
1018                 if (ret) {
1019                         printf("Error: writing directory entry\n");
1020                         goto exit;
1021                 }
1022         } else {
1023                 /* Set short name to set alias checksum field in dir_slot */
1024                 set_name(empty_dentptr, filename);
1025                 fill_dir_slot(mydata, &empty_dentptr, filename);
1026
1027                 ret = start_cluster = find_empty_cluster(mydata);
1028                 if (ret < 0) {
1029                         printf("Error: finding empty cluster\n");
1030                         goto exit;
1031                 }
1032
1033                 ret = check_overflow(mydata, start_cluster, size);
1034                 if (ret) {
1035                         printf("Error: %ld overflow\n", size);
1036                         goto exit;
1037                 }
1038
1039                 /* Set attribute as archieve for regular file */
1040                 fill_dentry(mydata, empty_dentptr, filename,
1041                         start_cluster, size, 0x20);
1042
1043                 ret = set_contents(mydata, empty_dentptr, buffer, size);
1044                 if (ret < 0) {
1045                         printf("Error: writing contents\n");
1046                         goto exit;
1047                 }
1048                 write_size = ret;
1049                 debug("attempt to write 0x%x bytes\n", write_size);
1050
1051                 /* Flush fat buffer */
1052                 ret = flush_fat_buffer(mydata);
1053                 if (ret) {
1054                         printf("Error: flush fat buffer\n");
1055                         goto exit;
1056                 }
1057
1058                 /* Write directory table to device */
1059                 ret = set_cluster(mydata, dir_curclust,
1060                             get_dentfromdir_block,
1061                             mydata->clust_size * mydata->sect_size);
1062                 if (ret) {
1063                         printf("Error: writing directory entry\n");
1064                         goto exit;
1065                 }
1066         }
1067
1068 exit:
1069         free(mydata->fatbuf);
1070         return ret < 0 ? ret : write_size;
1071 }
1072
1073 int file_fat_write(const char *filename, void *buffer, unsigned long maxsize)
1074 {
1075         printf("writing %s\n", filename);
1076         return do_fat_write(filename, buffer, maxsize);
1077 }