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  * See file CREDITS for list of people who contributed to this
   7  * project.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  22  * MA 02111-1307 USA
  23  */
  24
  25 #include <common.h>
  26 #include <command.h>
  27 #include <config.h>
  28 #include <fat.h>
  29 #include <asm/byteorder.h>
  30 #include <part.h>
  31 #include <linux/ctype.h>
  32 #include "fat.c"
  33
  34 static void uppercase(char *str, int len)
  35 {
  36         int i;
  37
  38         for (i = 0; i < len; i++) {
  39                 *str = toupper(*str);
  40                 str++;
  41         }
  42 }
  43
  44 static int total_sector;
  45 static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
  46 {
  47         if (!cur_dev || !cur_dev->block_write)
  48                 return -1;
  49
  50         if (cur_part_info.start + block + nr_blocks >
  51                 cur_part_info.start + total_sector) {
  52                 printf("error: overflow occurs\n");
  53                 return -1;
  54         }
  55
  56         return cur_dev->block_write(cur_dev->dev,
  57                         cur_part_info.start + block, nr_blocks, buf);
  58 }
  59
  60 /*
  61  * Set short name in directory entry
  62  */
  63 static void set_name(dir_entry *dirent, const char *filename)
  64 {
  65         char s_name[VFAT_MAXLEN_BYTES];
  66         char *period;
  67         int period_location, len, i, ext_num;
  68
  69         if (filename == NULL)
  70                 return;
  71
  72         len = strlen(filename);
  73         if (len == 0)
  74                 return;
  75
  76         memcpy(s_name, filename, len);
  77         uppercase(s_name, len);
  78
  79         period = strchr(s_name, '.');
  80         if (period == NULL) {
  81                 period_location = len;
  82                 ext_num = 0;
  83         } else {
  84                 period_location = period - s_name;
  85                 ext_num = len - period_location - 1;
  86         }
  87
  88         /* Pad spaces when the length of file name is shorter than eight */
  89         if (period_location < 8) {
  90                 memcpy(dirent->name, s_name, period_location);
  91                 for (i = period_location; i < 8; i++)
  92                         dirent->name[i] = ' ';
  93         } else if (period_location == 8) {
  94                 memcpy(dirent->name, s_name, period_location);
  95         } else {
  96                 memcpy(dirent->name, s_name, 6);
  97                 dirent->name[6] = '~';
  98                 dirent->name[7] = '1';
  99         }
 100
 101         if (ext_num < 3) {
 102                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
 103                 for (i = ext_num; i < 3; i++)
 104                         dirent->ext[i] = ' ';
 105         } else
 106                 memcpy(dirent->ext, s_name + period_location + 1, 3);
 107
 108         debug("name : %s\n", dirent->name);
 109         debug("ext : %s\n", dirent->ext);
 110 }
 111
 112 static __u8 num_of_fats;
 113 /*
 114  * Write fat buffer into block device
 115  */
 116 static int flush_fat_buffer(fsdata *mydata)
 117 {
 118         int getsize = FATBUFBLOCKS;
 119         __u32 fatlength = mydata->fatlength;
 120         __u8 *bufptr = mydata->fatbuf;
 121         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 122
 123         fatlength *= mydata->sect_size;
 124         startblock += mydata->fat_sect;
 125
 126         if (getsize > fatlength)
 127                 getsize = fatlength;
 128
 129         /* Write FAT buf */
 130         if (disk_write(startblock, getsize, bufptr) < 0) {
 131                 debug("error: writing FAT blocks\n");
 132                 return -1;
 133         }
 134
 135         if (num_of_fats == 2) {
 136                 /* Update corresponding second FAT blocks */
 137                 startblock += mydata->fatlength;
 138                 if (disk_write(startblock, getsize, bufptr) < 0) {
 139                         debug("error: writing second FAT blocks\n");
 140                         return -1;
 141                 }
 142         }
 143
 144         return 0;
 145 }
 146
 147 /*
 148  * Get the entry at index 'entry' in a FAT (12/16/32) table.
 149  * On failure 0x00 is returned.
 150  * When bufnum is changed, write back the previous fatbuf to the disk.
 151  */
 152 static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
 153 {
 154         __u32 bufnum;
 155         __u32 off16, offset;
 156         __u32 ret = 0x00;
 157         __u16 val1, val2;
 158
 159         switch (mydata->fatsize) {
 160         case 32:
 161                 bufnum = entry / FAT32BUFSIZE;
 162                 offset = entry - bufnum * FAT32BUFSIZE;
 163                 break;
 164         case 16:
 165                 bufnum = entry / FAT16BUFSIZE;
 166                 offset = entry - bufnum * FAT16BUFSIZE;
 167                 break;
 168         case 12:
 169                 bufnum = entry / FAT12BUFSIZE;
 170                 offset = entry - bufnum * FAT12BUFSIZE;
 171                 break;
 172
 173         default:
 174                 /* Unsupported FAT size */
 175                 return ret;
 176         }
 177
 178         debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
 179                mydata->fatsize, entry, entry, offset, offset);
 180
 181         /* Read a new block of FAT entries into the cache. */
 182         if (bufnum != mydata->fatbufnum) {
 183                 int getsize = FATBUFBLOCKS;
 184                 __u8 *bufptr = mydata->fatbuf;
 185                 __u32 fatlength = mydata->fatlength;
 186                 __u32 startblock = bufnum * FATBUFBLOCKS;
 187
 188                 if (getsize > fatlength)
 189                         getsize = fatlength;
 190
 191                 fatlength *= mydata->sect_size; /* We want it in bytes now */
 192                 startblock += mydata->fat_sect; /* Offset from start of disk */
 193
 194                 /* Write back the fatbuf to the disk */
 195                 if (mydata->fatbufnum != -1) {
 196                         if (flush_fat_buffer(mydata) < 0)
 197                                 return -1;
 198                 }
 199
 200                 if (disk_read(startblock, getsize, bufptr) < 0) {
 201                         debug("Error reading FAT blocks\n");
 202                         return ret;
 203                 }
 204                 mydata->fatbufnum = bufnum;
 205         }
 206
 207         /* Get the actual entry from the table */
 208         switch (mydata->fatsize) {
 209         case 32:
 210                 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
 211                 break;
 212         case 16:
 213                 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
 214                 break;
 215         case 12:
 216                 off16 = (offset * 3) / 4;
 217
 218                 switch (offset & 0x3) {
 219                 case 0:
 220                         ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
 221                         ret &= 0xfff;
 222                         break;
 223                 case 1:
 224                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 225                         val1 &= 0xf000;
 226                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 227                         val2 &= 0x00ff;
 228                         ret = (val2 << 4) | (val1 >> 12);
 229                         break;
 230                 case 2:
 231                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 232                         val1 &= 0xff00;
 233                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 234                         val2 &= 0x000f;
 235                         ret = (val2 << 8) | (val1 >> 8);
 236                         break;
 237                 case 3:
 238                         ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 239                         ret = (ret & 0xfff0) >> 4;
 240                         break;
 241                 default:
 242                         break;
 243                 }
 244                 break;
 245         }
 246         debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
 247                mydata->fatsize, ret, entry, offset);
 248
 249         return ret;
 250 }
 251
 252 #ifdef CONFIG_SUPPORT_VFAT
 253 /*
 254  * Set the file name information from 'name' into 'slotptr',
 255  */
 256 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 257 {
 258         int j, end_idx = 0;
 259
 260         for (j = 0; j <= 8; j += 2) {
 261                 if (name[*idx] == 0x00) {
 262                         slotptr->name0_4[j] = 0;
 263                         slotptr->name0_4[j + 1] = 0;
 264                         end_idx++;
 265                         goto name0_4;
 266                 }
 267                 slotptr->name0_4[j] = name[*idx];
 268                 (*idx)++;
 269                 end_idx++;
 270         }
 271         for (j = 0; j <= 10; j += 2) {
 272                 if (name[*idx] == 0x00) {
 273                         slotptr->name5_10[j] = 0;
 274                         slotptr->name5_10[j + 1] = 0;
 275                         end_idx++;
 276                         goto name5_10;
 277                 }
 278                 slotptr->name5_10[j] = name[*idx];
 279                 (*idx)++;
 280                 end_idx++;
 281         }
 282         for (j = 0; j <= 2; j += 2) {
 283                 if (name[*idx] == 0x00) {
 284                         slotptr->name11_12[j] = 0;
 285                         slotptr->name11_12[j + 1] = 0;
 286                         end_idx++;
 287                         goto name11_12;
 288                 }
 289                 slotptr->name11_12[j] = name[*idx];
 290                 (*idx)++;
 291                 end_idx++;
 292         }
 293
 294         if (name[*idx] == 0x00)
 295                 return 1;
 296
 297         return 0;
 298 /* Not used characters are filled with 0xff 0xff */
 299 name0_4:
 300         for (; end_idx < 5; end_idx++) {
 301                 slotptr->name0_4[end_idx * 2] = 0xff;
 302                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 303         }
 304         end_idx = 5;
 305 name5_10:
 306         end_idx -= 5;
 307         for (; end_idx < 6; end_idx++) {
 308                 slotptr->name5_10[end_idx * 2] = 0xff;
 309                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 310         }
 311         end_idx = 11;
 312 name11_12:
 313         end_idx -= 11;
 314         for (; end_idx < 2; end_idx++) {
 315                 slotptr->name11_12[end_idx * 2] = 0xff;
 316                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 317         }
 318
 319         return 1;
 320 }
 321
 322 static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
 323 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
 324
 325 /*
 326  * Fill dir_slot entries with appropriate name, id, and attr
 327  * The real directory entry is returned by 'dentptr'
 328  */
 329 static void
 330 fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
 331 {
 332         dir_slot *slotptr = (dir_slot *)get_contents_vfatname_block;
 333         __u8 counter = 0, checksum;
 334         int idx = 0, ret;
 335         char s_name[16];
 336
 337         /* Get short file name and checksum value */
 338         strncpy(s_name, (*dentptr)->name, 16);
 339         checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
 340
 341         do {
 342                 memset(slotptr, 0x00, sizeof(dir_slot));
 343                 ret = str2slot(slotptr, l_name, &idx);
 344                 slotptr->id = ++counter;
 345                 slotptr->attr = ATTR_VFAT;
 346                 slotptr->alias_checksum = checksum;
 347                 slotptr++;
 348         } while (ret == 0);
 349
 350         slotptr--;
 351         slotptr->id |= LAST_LONG_ENTRY_MASK;
 352
 353         while (counter >= 1) {
 354                 if (is_next_clust(mydata, *dentptr)) {
 355                         /* A new cluster is allocated for directory table */
 356                         flush_dir_table(mydata, dentptr);
 357                 }
 358                 memcpy(*dentptr, slotptr, sizeof(dir_slot));
 359                 (*dentptr)++;
 360                 slotptr--;
 361                 counter--;
 362         }
 363
 364         if (is_next_clust(mydata, *dentptr)) {
 365                 /* A new cluster is allocated for directory table */
 366                 flush_dir_table(mydata, dentptr);
 367         }
 368 }
 369
 370 static __u32 dir_curclust;
 371
 372 /*
 373  * Extract the full long filename starting at 'retdent' (which is really
 374  * a slot) into 'l_name'. If successful also copy the real directory entry
 375  * into 'retdent'
 376  * If additional adjacent cluster for directory entries is read into memory,
 377  * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
 378  * the location of the real directory entry is returned by 'retdent'
 379  * Return 0 on success, -1 otherwise.
 380  */
 381 static int
 382 get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
 383               dir_entry **retdent, char *l_name)
 384 {
 385         dir_entry *realdent;
 386         dir_slot *slotptr = (dir_slot *)(*retdent);
 387         dir_slot *slotptr2 = NULL;
 388         __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
 389                                                         PREFETCH_BLOCKS :
 390                                                         mydata->clust_size);
 391         __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
 392         int idx = 0, cur_position = 0;
 393
 394         if (counter > VFAT_MAXSEQ) {
 395                 debug("Error: VFAT name is too long\n");
 396                 return -1;
 397         }
 398
 399         while ((__u8 *)slotptr < buflimit) {
 400                 if (counter == 0)
 401                         break;
 402                 if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
 403                         return -1;
 404                 slotptr++;
 405                 counter--;
 406         }
 407
 408         if ((__u8 *)slotptr >= buflimit) {
 409                 if (curclust == 0)
 410                         return -1;
 411                 curclust = get_fatent_value(mydata, dir_curclust);
 412                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 413                         debug("curclust: 0x%x\n", curclust);
 414                         printf("Invalid FAT entry\n");
 415                         return -1;
 416                 }
 417
 418                 dir_curclust = curclust;
 419
 420                 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
 421                                 mydata->clust_size * mydata->sect_size) != 0) {
 422                         debug("Error: reading directory block\n");
 423                         return -1;
 424                 }
 425
 426                 slotptr2 = (dir_slot *)get_contents_vfatname_block;
 427                 while (counter > 0) {
 428                         if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
 429                             & 0xff) != counter)
 430                                 return -1;
 431                         slotptr2++;
 432                         counter--;
 433                 }
 434
 435                 /* Save the real directory entry */
 436                 realdent = (dir_entry *)slotptr2;
 437                 while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
 438                         slotptr2--;
 439                         slot2str(slotptr2, l_name, &idx);
 440                 }
 441         } else {
 442                 /* Save the real directory entry */
 443                 realdent = (dir_entry *)slotptr;
 444         }
 445
 446         do {
 447                 slotptr--;
 448                 if (slot2str(slotptr, l_name, &idx))
 449                         break;
 450         } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
 451
 452         l_name[idx] = '\0';
 453         if (*l_name == DELETED_FLAG)
 454                 *l_name = '\0';
 455         else if (*l_name == aRING)
 456                 *l_name = DELETED_FLAG;
 457         downcase(l_name);
 458
 459         /* Return the real directory entry */
 460         *retdent = realdent;
 461
 462         if (slotptr2) {
 463                 memcpy(get_dentfromdir_block, get_contents_vfatname_block,
 464                         mydata->clust_size * mydata->sect_size);
 465                 cur_position = (__u8 *)realdent - get_contents_vfatname_block;
 466                 *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
 467         }
 468
 469         return 0;
 470 }
 471
 472 #endif
 473
 474 /*
 475  * Set the entry at index 'entry' in a FAT (16/32) table.
 476  */
 477 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 478 {
 479         __u32 bufnum, offset;
 480
 481         switch (mydata->fatsize) {
 482         case 32:
 483                 bufnum = entry / FAT32BUFSIZE;
 484                 offset = entry - bufnum * FAT32BUFSIZE;
 485                 break;
 486         case 16:
 487                 bufnum = entry / FAT16BUFSIZE;
 488                 offset = entry - bufnum * FAT16BUFSIZE;
 489                 break;
 490         default:
 491                 /* Unsupported FAT size */
 492                 return -1;
 493         }
 494
 495         /* Read a new block of FAT entries into the cache. */
 496         if (bufnum != mydata->fatbufnum) {
 497                 int getsize = FATBUFBLOCKS;
 498                 __u8 *bufptr = mydata->fatbuf;
 499                 __u32 fatlength = mydata->fatlength;
 500                 __u32 startblock = bufnum * FATBUFBLOCKS;
 501
 502                 fatlength *= mydata->sect_size;
 503                 startblock += mydata->fat_sect;
 504
 505                 if (getsize > fatlength)
 506                         getsize = fatlength;
 507
 508                 if (mydata->fatbufnum != -1) {
 509                         if (flush_fat_buffer(mydata) < 0)
 510                                 return -1;
 511                 }
 512
 513                 if (disk_read(startblock, getsize, bufptr) < 0) {
 514                         debug("Error reading FAT blocks\n");
 515                         return -1;
 516                 }
 517                 mydata->fatbufnum = bufnum;
 518         }
 519
 520         /* Set the actual entry */
 521         switch (mydata->fatsize) {
 522         case 32:
 523                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 524                 break;
 525         case 16:
 526                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 527                 break;
 528         default:
 529                 return -1;
 530         }
 531
 532         return 0;
 533 }
 534
 535 /*
 536  * Determine the entry value at index 'entry' in a FAT (16/32) table
 537  */
 538 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 539 {
 540         __u32 next_fat, next_entry = entry + 1;
 541
 542         while (1) {
 543                 next_fat = get_fatent_value(mydata, next_entry);
 544                 if (next_fat == 0) {
 545                         set_fatent_value(mydata, entry, next_entry);
 546                         break;
 547                 }
 548                 next_entry++;
 549         }
 550         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 551                mydata->fatsize, entry, next_entry);
 552
 553         return next_entry;
 554 }
 555
 556 /*
 557  * Write at most 'size' bytes from 'buffer' into the specified cluster.
 558  * Return 0 on success, -1 otherwise.
 559  */
 560 static int
 561 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 562              unsigned long size)
 563 {
 564         int idx = 0;
 565         __u32 startsect;
 566
 567         if (clustnum > 0)
 568                 startsect = mydata->data_begin +
 569                                 clustnum * mydata->clust_size;
 570         else
 571                 startsect = mydata->rootdir_sect;
 572
 573         debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 574
 575         if (disk_write(startsect, size / mydata->sect_size, buffer) < 0) {
 576                 debug("Error writing data\n");
 577                 return -1;
 578         }
 579
 580         if (size % mydata->sect_size) {
 581                 __u8 tmpbuf[mydata->sect_size];
 582
 583                 idx = size / mydata->sect_size;
 584                 buffer += idx * mydata->sect_size;
 585                 memcpy(tmpbuf, buffer, size % mydata->sect_size);
 586
 587                 if (disk_write(startsect + idx, 1, tmpbuf) < 0) {
 588                         debug("Error writing data\n");
 589                         return -1;
 590                 }
 591
 592                 return 0;
 593         }
 594
 595         return 0;
 596 }
 597
 598 /*
 599  * Find the first empty cluster
 600  */
 601 static int find_empty_cluster(fsdata *mydata)
 602 {
 603         __u32 fat_val, entry = 3;
 604
 605         while (1) {
 606                 fat_val = get_fatent_value(mydata, entry);
 607                 if (fat_val == 0)
 608                         break;
 609                 entry++;
 610         }
 611
 612         return entry;
 613 }
 614
 615 /*
 616  * Write directory entries in 'get_dentfromdir_block' to block device
 617  */
 618 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
 619 {
 620         int dir_newclust = 0;
 621
 622         if (set_cluster(mydata, dir_curclust,
 623                     get_dentfromdir_block,
 624                     mydata->clust_size * mydata->sect_size) != 0) {
 625                 printf("error: wrinting directory entry\n");
 626                 return;
 627         }
 628         dir_newclust = find_empty_cluster(mydata);
 629         set_fatent_value(mydata, dir_curclust, dir_newclust);
 630         if (mydata->fatsize == 32)
 631                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 632         else if (mydata->fatsize == 16)
 633                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 634
 635         dir_curclust = dir_newclust;
 636
 637         if (flush_fat_buffer(mydata) < 0)
 638                 return;
 639
 640         memset(get_dentfromdir_block, 0x00,
 641                 mydata->clust_size * mydata->sect_size);
 642
 643         *dentptr = (dir_entry *) get_dentfromdir_block;
 644 }
 645
 646 /*
 647  * Set empty cluster from 'entry' to the end of a file
 648  */
 649 static int clear_fatent(fsdata *mydata, __u32 entry)
 650 {
 651         __u32 fat_val;
 652
 653         while (1) {
 654                 fat_val = get_fatent_value(mydata, entry);
 655                 if (fat_val != 0)
 656                         set_fatent_value(mydata, entry, 0);
 657                 else
 658                         break;
 659
 660                 if (fat_val == 0xfffffff || fat_val == 0xffff)
 661                         break;
 662
 663                 entry = fat_val;
 664         }
 665
 666         /* Flush fat buffer */
 667         if (flush_fat_buffer(mydata) < 0)
 668                 return -1;
 669
 670         return 0;
 671 }
 672
 673 /*
 674  * Write at most 'maxsize' bytes from 'buffer' into
 675  * the file associated with 'dentptr'
 676  * Return the number of bytes read or -1 on fatal errors.
 677  */
 678 static int
 679 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
 680               unsigned long maxsize)
 681 {
 682         unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
 683         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 684         __u32 curclust = START(dentptr);
 685         __u32 endclust = 0, newclust = 0;
 686         unsigned long actsize;
 687
 688         debug("Filesize: %ld bytes\n", filesize);
 689
 690         if (maxsize > 0 && filesize > maxsize)
 691                 filesize = maxsize;
 692
 693         debug("%ld bytes\n", filesize);
 694
 695         actsize = bytesperclust;
 696         endclust = curclust;
 697         do {
 698                 /* search for consecutive clusters */
 699                 while (actsize < filesize) {
 700                         newclust = determine_fatent(mydata, endclust);
 701
 702                         if ((newclust - 1) != endclust)
 703                                 goto getit;
 704
 705                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 706                                 debug("curclust: 0x%x\n", newclust);
 707                                 debug("Invalid FAT entry\n");
 708                                 return gotsize;
 709                         }
 710                         endclust = newclust;
 711                         actsize += bytesperclust;
 712                 }
 713                 /* actsize >= file size */
 714                 actsize -= bytesperclust;
 715                 /* set remaining clusters */
 716                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 717                         debug("error: writing cluster\n");
 718                         return -1;
 719                 }
 720
 721                 /* set remaining bytes */
 722                 gotsize += (int)actsize;
 723                 filesize -= actsize;
 724                 buffer += actsize;
 725                 actsize = filesize;
 726
 727                 if (set_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
 728                         debug("error: writing cluster\n");
 729                         return -1;
 730                 }
 731                 gotsize += actsize;
 732
 733                 /* Mark end of file in FAT */
 734                 if (mydata->fatsize == 16)
 735                         newclust = 0xffff;
 736                 else if (mydata->fatsize == 32)
 737                         newclust = 0xfffffff;
 738                 set_fatent_value(mydata, endclust, newclust);
 739
 740                 return gotsize;
 741 getit:
 742                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 743                         debug("error: writing cluster\n");
 744                         return -1;
 745                 }
 746                 gotsize += (int)actsize;
 747                 filesize -= actsize;
 748                 buffer += actsize;
 749
 750                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 751                         debug("curclust: 0x%x\n", curclust);
 752                         debug("Invalid FAT entry\n");
 753                         return gotsize;
 754                 }
 755                 actsize = bytesperclust;
 756                 curclust = endclust = newclust;
 757         } while (1);
 758 }
 759
 760 /*
 761  * Fill dir_entry
 762  */
 763 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 764         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 765 {
 766         if (mydata->fatsize == 32)
 767                 dentptr->starthi =
 768                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 769         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 770         dentptr->size = cpu_to_le32(size);
 771
 772         dentptr->attr = attr;
 773
 774         set_name(dentptr, filename);
 775 }
 776
 777 /*
 778  * Check whether adding a file makes the file system to
 779  * exceed the size of the block device
 780  * Return -1 when overflow occurs, otherwise return 0
 781  */
 782 static int check_overflow(fsdata *mydata, __u32 clustnum, unsigned long size)
 783 {
 784         __u32 startsect, sect_num;
 785
 786         if (clustnum > 0) {
 787                 startsect = mydata->data_begin +
 788                                 clustnum * mydata->clust_size;
 789         } else {
 790                 startsect = mydata->rootdir_sect;
 791         }
 792
 793         sect_num = size / mydata->sect_size;
 794         if (size % mydata->sect_size)
 795                 sect_num++;
 796
 797         if (startsect + sect_num > cur_part_info.start + total_sector)
 798                 return -1;
 799
 800         return 0;
 801 }
 802
 803 /*
 804  * Check if adding several entries exceed one cluster boundary
 805  */
 806 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
 807 {
 808         int cur_position;
 809
 810         cur_position = (__u8 *)dentptr - get_dentfromdir_block;
 811
 812         if (cur_position >= mydata->clust_size * mydata->sect_size)
 813                 return 1;
 814         else
 815                 return 0;
 816 }
 817
 818 static dir_entry *empty_dentptr;
 819 /*
 820  * Find a directory entry based on filename or start cluster number
 821  * If the directory entry is not found,
 822  * the new position for writing a directory entry will be returned
 823  */
 824 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
 825         char *filename, dir_entry *retdent, __u32 start)
 826 {
 827         __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
 828
 829         debug("get_dentfromdir: %s\n", filename);
 830
 831         while (1) {
 832                 dir_entry *dentptr;
 833
 834                 int i;
 835
 836                 if (get_cluster(mydata, curclust, get_dentfromdir_block,
 837                             mydata->clust_size * mydata->sect_size) != 0) {
 838                         printf("Error: reading directory block\n");
 839                         return NULL;
 840                 }
 841
 842                 dentptr = (dir_entry *)get_dentfromdir_block;
 843
 844                 dir_curclust = curclust;
 845
 846                 for (i = 0; i < DIRENTSPERCLUST; i++) {
 847                         char s_name[14], l_name[VFAT_MAXLEN_BYTES];
 848
 849                         l_name[0] = '\0';
 850                         if (dentptr->name[0] == DELETED_FLAG) {
 851                                 dentptr++;
 852                                 if (is_next_clust(mydata, dentptr))
 853                                         break;
 854                                 continue;
 855                         }
 856                         if ((dentptr->attr & ATTR_VOLUME)) {
 857 #ifdef CONFIG_SUPPORT_VFAT
 858                                 if ((dentptr->attr & ATTR_VFAT) &&
 859                                     (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
 860                                         get_long_file_name(mydata, curclust,
 861                                                      get_dentfromdir_block,
 862                                                      &dentptr, l_name);
 863                                         debug("vfatname: |%s|\n", l_name);
 864                                 } else
 865 #endif
 866                                 {
 867                                         /* Volume label or VFAT entry */
 868                                         dentptr++;
 869                                         if (is_next_clust(mydata, dentptr))
 870                                                 break;
 871                                         continue;
 872                                 }
 873                         }
 874                         if (dentptr->name[0] == 0) {
 875                                 debug("Dentname == NULL - %d\n", i);
 876                                 empty_dentptr = dentptr;
 877                                 return NULL;
 878                         }
 879
 880                         get_name(dentptr, s_name);
 881
 882                         if (strcmp(filename, s_name)
 883                             && strcmp(filename, l_name)) {
 884                                 debug("Mismatch: |%s|%s|\n",
 885                                         s_name, l_name);
 886                                 dentptr++;
 887                                 if (is_next_clust(mydata, dentptr))
 888                                         break;
 889                                 continue;
 890                         }
 891
 892                         memcpy(retdent, dentptr, sizeof(dir_entry));
 893
 894                         debug("DentName: %s", s_name);
 895                         debug(", start: 0x%x", START(dentptr));
 896                         debug(", size:  0x%x %s\n",
 897                               FAT2CPU32(dentptr->size),
 898                               (dentptr->attr & ATTR_DIR) ?
 899                               "(DIR)" : "");
 900
 901                         return dentptr;
 902                 }
 903
 904                 curclust = get_fatent_value(mydata, dir_curclust);
 905                 if ((curclust >= 0xffffff8) || (curclust >= 0xfff8)) {
 906                         empty_dentptr = dentptr;
 907                         return NULL;
 908                 }
 909                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 910                         debug("curclust: 0x%x\n", curclust);
 911                         debug("Invalid FAT entry\n");
 912                         return NULL;
 913                 }
 914         }
 915
 916         return NULL;
 917 }
 918
 919 static int do_fat_write(const char *filename, void *buffer,
 920         unsigned long size)
 921 {
 922         dir_entry *dentptr, *retdent;
 923         __u32 startsect;
 924         __u32 start_cluster;
 925         boot_sector bs;
 926         volume_info volinfo;
 927         fsdata datablock;
 928         fsdata *mydata = &datablock;
 929         int cursect;
 930         int ret = -1, name_len;
 931         char l_filename[VFAT_MAXLEN_BYTES];
 932         int write_size = size;
 933
 934         dir_curclust = 0;
 935
 936         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 937                 debug("error: reading boot sector\n");
 938                 return -1;
 939         }
 940
 941         total_sector = bs.total_sect;
 942         if (total_sector == 0)
 943                 total_sector = cur_part_info.size;
 944
 945         if (mydata->fatsize == 32)
 946                 mydata->fatlength = bs.fat32_length;
 947         else
 948                 mydata->fatlength = bs.fat_length;
 949
 950         mydata->fat_sect = bs.reserved;
 951
 952         cursect = mydata->rootdir_sect
 953                 = mydata->fat_sect + mydata->fatlength * bs.fats;
 954         num_of_fats = bs.fats;
 955
 956         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
 957         mydata->clust_size = bs.cluster_size;
 958
 959         if (mydata->fatsize == 32) {
 960                 mydata->data_begin = mydata->rootdir_sect -
 961                                         (mydata->clust_size * 2);
 962         } else {
 963                 int rootdir_size;
 964
 965                 rootdir_size = ((bs.dir_entries[1]  * (int)256 +
 966                                  bs.dir_entries[0]) *
 967                                  sizeof(dir_entry)) /
 968                                  mydata->sect_size;
 969                 mydata->data_begin = mydata->rootdir_sect +
 970                                         rootdir_size -
 971                                         (mydata->clust_size * 2);
 972         }
 973
 974         mydata->fatbufnum = -1;
 975         mydata->fatbuf = malloc(FATBUFSIZE);
 976         if (mydata->fatbuf == NULL) {
 977                 debug("Error: allocating memory\n");
 978                 return -1;
 979         }
 980
 981         if (disk_read(cursect,
 982                 (mydata->fatsize == 32) ?
 983                 (mydata->clust_size) :
 984                 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
 985                 debug("Error: reading rootdir block\n");
 986                 goto exit;
 987         }
 988         dentptr = (dir_entry *) do_fat_read_at_block;
 989
 990         name_len = strlen(filename);
 991         if (name_len >= VFAT_MAXLEN_BYTES)
 992                 name_len = VFAT_MAXLEN_BYTES - 1;
 993
 994         memcpy(l_filename, filename, name_len);
 995         l_filename[name_len] = 0; /* terminate the string */
 996         downcase(l_filename);
 997
 998         startsect = mydata->rootdir_sect;
 999         retdent = find_directory_entry(mydata, startsect,
1000                                 l_filename, dentptr, 0);
1001         if (retdent) {
1002                 /* Update file size and start_cluster in a directory entry */
1003                 retdent->size = cpu_to_le32(size);
1004                 start_cluster = FAT2CPU16(retdent->start);
1005                 if (mydata->fatsize == 32)
1006                         start_cluster |=
1007                                 (FAT2CPU16(retdent->starthi) << 16);
1008
1009                 ret = check_overflow(mydata, start_cluster, size);
1010                 if (ret) {
1011                         printf("Error: %ld overflow\n", size);
1012                         goto exit;
1013                 }
1014
1015                 ret = clear_fatent(mydata, start_cluster);
1016                 if (ret) {
1017                         printf("Error: clearing FAT entries\n");
1018                         goto exit;
1019                 }
1020
1021                 ret = set_contents(mydata, retdent, buffer, size);
1022                 if (ret < 0) {
1023                         printf("Error: writing contents\n");
1024                         goto exit;
1025                 }
1026                 write_size = ret;
1027                 debug("attempt to write 0x%x bytes\n", write_size);
1028
1029                 /* Flush fat buffer */
1030                 ret = flush_fat_buffer(mydata);
1031                 if (ret) {
1032                         printf("Error: flush fat buffer\n");
1033                         goto exit;
1034                 }
1035
1036                 /* Write directory table to device */
1037                 ret = set_cluster(mydata, dir_curclust,
1038                             get_dentfromdir_block,
1039                             mydata->clust_size * mydata->sect_size);
1040                 if (ret) {
1041                         printf("Error: writing directory entry\n");
1042                         goto exit;
1043                 }
1044         } else {
1045                 /* Set short name to set alias checksum field in dir_slot */
1046                 set_name(empty_dentptr, filename);
1047                 fill_dir_slot(mydata, &empty_dentptr, filename);
1048
1049                 ret = start_cluster = find_empty_cluster(mydata);
1050                 if (ret < 0) {
1051                         printf("Error: finding empty cluster\n");
1052                         goto exit;
1053                 }
1054
1055                 ret = check_overflow(mydata, start_cluster, size);
1056                 if (ret) {
1057                         printf("Error: %ld overflow\n", size);
1058                         goto exit;
1059                 }
1060
1061                 /* Set attribute as archieve for regular file */
1062                 fill_dentry(mydata, empty_dentptr, filename,
1063                         start_cluster, size, 0x20);
1064
1065                 ret = set_contents(mydata, empty_dentptr, buffer, size);
1066                 if (ret < 0) {
1067                         printf("Error: writing contents\n");
1068                         goto exit;
1069                 }
1070                 write_size = ret;
1071                 debug("attempt to write 0x%x bytes\n", write_size);
1072
1073                 /* Flush fat buffer */
1074                 ret = flush_fat_buffer(mydata);
1075                 if (ret) {
1076                         printf("Error: flush fat buffer\n");
1077                         goto exit;
1078                 }
1079
1080                 /* Write directory table to device */
1081                 ret = set_cluster(mydata, dir_curclust,
1082                             get_dentfromdir_block,
1083                             mydata->clust_size * mydata->sect_size);
1084                 if (ret) {
1085                         printf("Error: writing directory entry\n");
1086                         goto exit;
1087                 }
1088         }
1089
1090 exit:
1091         free(mydata->fatbuf);
1092         return ret < 0 ? ret : write_size;
1093 }
1094
1095 int file_fat_write(const char *filename, void *buffer, unsigned long maxsize)
1096 {
1097         printf("writing %s\n", filename);
1098         return do_fat_write(filename, buffer, maxsize);
1099 }