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