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 startblock, __u32 getsize, __u8 *bufptr)
  45 {
  46         if (cur_dev == NULL)
  47                 return -1;
  48
  49         if (startblock + getsize > total_sector) {
  50                 printf("error: overflow occurs\n");
  51                 return -1;
  52         }
  53
  54         startblock += part_offset;
  55
  56         if (cur_dev->block_read) {
  57                 return cur_dev->block_write(cur_dev->dev, startblock, getsize,
  58                                            (unsigned long *) bufptr);
  59         }
  60         return -1;
  61 }
  62
  63 /*
  64  * Set short name in directory entry
  65  */
  66 static void set_name(dir_entry *dirent, const char *filename)
  67 {
  68         char s_name[VFAT_MAXLEN_BYTES];
  69         char *period;
  70         int period_location, len, i, ext_num;
  71
  72         if (filename == NULL)
  73                 return;
  74
  75         len = strlen(filename);
  76         if (len == 0)
  77                 return;
  78
  79         memcpy(s_name, filename, len);
  80         uppercase(s_name, len);
  81
  82         period = strchr(s_name, '.');
  83         if (period == NULL) {
  84                 period_location = len;
  85                 ext_num = 0;
  86         } else {
  87                 period_location = period - s_name;
  88                 ext_num = len - period_location - 1;
  89         }
  90
  91         /* Pad spaces when the length of file name is shorter than eight */
  92         if (period_location < 8) {
  93                 memcpy(dirent->name, s_name, period_location);
  94                 for (i = period_location; i < 8; i++)
  95                         dirent->name[i] = ' ';
  96         } else if (period_location == 8) {
  97                 memcpy(dirent->name, s_name, period_location);
  98         } else {
  99                 memcpy(dirent->name, s_name, 6);
 100                 dirent->name[6] = '~';
 101                 dirent->name[7] = '1';
 102         }
 103
 104         if (ext_num < 3) {
 105                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
 106                 for (i = ext_num; i < 3; i++)
 107                         dirent->ext[i] = ' ';
 108         } else
 109                 memcpy(dirent->ext, s_name + period_location + 1, 3);
 110
 111         debug("name : %s\n", dirent->name);
 112         debug("ext : %s\n", dirent->ext);
 113 }
 114
 115 static __u8 num_of_fats;
 116 /*
 117  * Write fat buffer into block device
 118  */
 119 static int flush_fat_buffer(fsdata *mydata)
 120 {
 121         int getsize = FATBUFBLOCKS;
 122         __u32 fatlength = mydata->fatlength;
 123         __u8 *bufptr = mydata->fatbuf;
 124         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 125
 126         fatlength *= mydata->sect_size;
 127         startblock += mydata->fat_sect;
 128
 129         if (getsize > fatlength)
 130                 getsize = fatlength;
 131
 132         /* Write FAT buf */
 133         if (disk_write(startblock, getsize, bufptr) < 0) {
 134                 debug("error: writing FAT blocks\n");
 135                 return -1;
 136         }
 137
 138         if (num_of_fats == 2) {
 139                 /* Update corresponding second FAT blocks */
 140                 startblock += mydata->fatlength;
 141                 if (disk_write(startblock, getsize, bufptr) < 0) {
 142                         debug("error: writing second FAT blocks\n");
 143                         return -1;
 144                 }
 145         }
 146
 147         return 0;
 148 }
 149
 150 /*
 151  * Get the entry at index 'entry' in a FAT (12/16/32) table.
 152  * On failure 0x00 is returned.
 153  * When bufnum is changed, write back the previous fatbuf to the disk.
 154  */
 155 static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
 156 {
 157         __u32 bufnum;
 158         __u32 off16, offset;
 159         __u32 ret = 0x00;
 160         __u16 val1, val2;
 161
 162         switch (mydata->fatsize) {
 163         case 32:
 164                 bufnum = entry / FAT32BUFSIZE;
 165                 offset = entry - bufnum * FAT32BUFSIZE;
 166                 break;
 167         case 16:
 168                 bufnum = entry / FAT16BUFSIZE;
 169                 offset = entry - bufnum * FAT16BUFSIZE;
 170                 break;
 171         case 12:
 172                 bufnum = entry / FAT12BUFSIZE;
 173                 offset = entry - bufnum * FAT12BUFSIZE;
 174                 break;
 175
 176         default:
 177                 /* Unsupported FAT size */
 178                 return ret;
 179         }
 180
 181         debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
 182                mydata->fatsize, entry, entry, offset, offset);
 183
 184         /* Read a new block of FAT entries into the cache. */
 185         if (bufnum != mydata->fatbufnum) {
 186                 int getsize = FATBUFBLOCKS;
 187                 __u8 *bufptr = mydata->fatbuf;
 188                 __u32 fatlength = mydata->fatlength;
 189                 __u32 startblock = bufnum * FATBUFBLOCKS;
 190
 191                 if (getsize > fatlength)
 192                         getsize = fatlength;
 193
 194                 fatlength *= mydata->sect_size; /* We want it in bytes now */
 195                 startblock += mydata->fat_sect; /* Offset from start of disk */
 196
 197                 /* Write back the fatbuf to the disk */
 198                 if (mydata->fatbufnum != -1) {
 199                         if (flush_fat_buffer(mydata) < 0)
 200                                 return -1;
 201                 }
 202
 203                 if (disk_read(startblock, getsize, bufptr) < 0) {
 204                         debug("Error reading FAT blocks\n");
 205                         return ret;
 206                 }
 207                 mydata->fatbufnum = bufnum;
 208         }
 209
 210         /* Get the actual entry from the table */
 211         switch (mydata->fatsize) {
 212         case 32:
 213                 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
 214                 break;
 215         case 16:
 216                 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
 217                 break;
 218         case 12:
 219                 off16 = (offset * 3) / 4;
 220
 221                 switch (offset & 0x3) {
 222                 case 0:
 223                         ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
 224                         ret &= 0xfff;
 225                         break;
 226                 case 1:
 227                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 228                         val1 &= 0xf000;
 229                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 230                         val2 &= 0x00ff;
 231                         ret = (val2 << 4) | (val1 >> 12);
 232                         break;
 233                 case 2:
 234                         val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 235                         val1 &= 0xff00;
 236                         val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
 237                         val2 &= 0x000f;
 238                         ret = (val2 << 8) | (val1 >> 8);
 239                         break;
 240                 case 3:
 241                         ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
 242                         ret = (ret & 0xfff0) >> 4;
 243                         break;
 244                 default:
 245                         break;
 246                 }
 247                 break;
 248         }
 249         debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
 250                mydata->fatsize, ret, entry, offset);
 251
 252         return ret;
 253 }
 254
 255 #ifdef CONFIG_SUPPORT_VFAT
 256 /*
 257  * Set the file name information from 'name' into 'slotptr',
 258  */
 259 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 260 {
 261         int j, end_idx = 0;
 262
 263         for (j = 0; j <= 8; j += 2) {
 264                 if (name[*idx] == 0x00) {
 265                         slotptr->name0_4[j] = 0;
 266                         slotptr->name0_4[j + 1] = 0;
 267                         end_idx++;
 268                         goto name0_4;
 269                 }
 270                 slotptr->name0_4[j] = name[*idx];
 271                 (*idx)++;
 272                 end_idx++;
 273         }
 274         for (j = 0; j <= 10; j += 2) {
 275                 if (name[*idx] == 0x00) {
 276                         slotptr->name5_10[j] = 0;
 277                         slotptr->name5_10[j + 1] = 0;
 278                         end_idx++;
 279                         goto name5_10;
 280                 }
 281                 slotptr->name5_10[j] = name[*idx];
 282                 (*idx)++;
 283                 end_idx++;
 284         }
 285         for (j = 0; j <= 2; j += 2) {
 286                 if (name[*idx] == 0x00) {
 287                         slotptr->name11_12[j] = 0;
 288                         slotptr->name11_12[j + 1] = 0;
 289                         end_idx++;
 290                         goto name11_12;
 291                 }
 292                 slotptr->name11_12[j] = name[*idx];
 293                 (*idx)++;
 294                 end_idx++;
 295         }
 296
 297         if (name[*idx] == 0x00)
 298                 return 1;
 299
 300         return 0;
 301 /* Not used characters are filled with 0xff 0xff */
 302 name0_4:
 303         for (; end_idx < 5; end_idx++) {
 304                 slotptr->name0_4[end_idx * 2] = 0xff;
 305                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 306         }
 307         end_idx = 5;
 308 name5_10:
 309         end_idx -= 5;
 310         for (; end_idx < 6; end_idx++) {
 311                 slotptr->name5_10[end_idx * 2] = 0xff;
 312                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 313         }
 314         end_idx = 11;
 315 name11_12:
 316         end_idx -= 11;
 317         for (; end_idx < 2; end_idx++) {
 318                 slotptr->name11_12[end_idx * 2] = 0xff;
 319                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 320         }
 321
 322         return 1;
 323 }
 324
 325 static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
 326 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
 327
 328 /*
 329  * Fill dir_slot entries with appropriate name, id, and attr
 330  * The real directory entry is returned by 'dentptr'
 331  */
 332 static void
 333 fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
 334 {
 335         dir_slot *slotptr = (dir_slot *)get_vfatname_block;
 336         __u8 counter = 0, checksum;
 337         int idx = 0, ret;
 338         char s_name[16];
 339
 340         /* Get short file name and checksum value */
 341         strncpy(s_name, (*dentptr)->name, 16);
 342         checksum = mkcksum(s_name);
 343
 344         do {
 345                 memset(slotptr, 0x00, sizeof(dir_slot));
 346                 ret = str2slot(slotptr, l_name, &idx);
 347                 slotptr->id = ++counter;
 348                 slotptr->attr = ATTR_VFAT;
 349                 slotptr->alias_checksum = checksum;
 350                 slotptr++;
 351         } while (ret == 0);
 352
 353         slotptr--;
 354         slotptr->id |= LAST_LONG_ENTRY_MASK;
 355
 356         while (counter >= 1) {
 357                 if (is_next_clust(mydata, *dentptr)) {
 358                         /* A new cluster is allocated for directory table */
 359                         flush_dir_table(mydata, dentptr);
 360                 }
 361                 memcpy(*dentptr, slotptr, sizeof(dir_slot));
 362                 (*dentptr)++;
 363                 slotptr--;
 364                 counter--;
 365         }
 366
 367         if (is_next_clust(mydata, *dentptr)) {
 368                 /* A new cluster is allocated for directory table */
 369                 flush_dir_table(mydata, dentptr);
 370         }
 371 }
 372
 373 static __u32 dir_curclust;
 374
 375 /*
 376  * Extract the full long filename starting at 'retdent' (which is really
 377  * a slot) into 'l_name'. If successful also copy the real directory entry
 378  * into 'retdent'
 379  * If additional adjacent cluster for directory entries is read into memory,
 380  * then 'get_vfatname_block' is copied into 'get_dentfromdir_block' and
 381  * the location of the real directory entry is returned by 'retdent'
 382  * Return 0 on success, -1 otherwise.
 383  */
 384 static int
 385 get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
 386               dir_entry **retdent, char *l_name)
 387 {
 388         dir_entry *realdent;
 389         dir_slot *slotptr = (dir_slot *)(*retdent);
 390         dir_slot *slotptr2 = NULL;
 391         __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
 392                                                         PREFETCH_BLOCKS :
 393                                                         mydata->clust_size);
 394         __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
 395         int idx = 0, cur_position = 0;
 396
 397         if (counter > VFAT_MAXSEQ) {
 398                 debug("Error: VFAT name is too long\n");
 399                 return -1;
 400         }
 401
 402         while ((__u8 *)slotptr < buflimit) {
 403                 if (counter == 0)
 404                         break;
 405                 if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
 406                         return -1;
 407                 slotptr++;
 408                 counter--;
 409         }
 410
 411         if ((__u8 *)slotptr >= buflimit) {
 412                 if (curclust == 0)
 413                         return -1;
 414                 curclust = get_fatent_value(mydata, dir_curclust);
 415                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 416                         debug("curclust: 0x%x\n", curclust);
 417                         printf("Invalid FAT entry\n");
 418                         return -1;
 419                 }
 420
 421                 dir_curclust = curclust;
 422
 423                 if (get_cluster(mydata, curclust, get_vfatname_block,
 424                                 mydata->clust_size * mydata->sect_size) != 0) {
 425                         debug("Error: reading directory block\n");
 426                         return -1;
 427                 }
 428
 429                 slotptr2 = (dir_slot *)get_vfatname_block;
 430                 while (counter > 0) {
 431                         if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
 432                             & 0xff) != counter)
 433                                 return -1;
 434                         slotptr2++;
 435                         counter--;
 436                 }
 437
 438                 /* Save the real directory entry */
 439                 realdent = (dir_entry *)slotptr2;
 440                 while ((__u8 *)slotptr2 > get_vfatname_block) {
 441                         slotptr2--;
 442                         slot2str(slotptr2, l_name, &idx);
 443                 }
 444         } else {
 445                 /* Save the real directory entry */
 446                 realdent = (dir_entry *)slotptr;
 447         }
 448
 449         do {
 450                 slotptr--;
 451                 if (slot2str(slotptr, l_name, &idx))
 452                         break;
 453         } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
 454
 455         l_name[idx] = '\0';
 456         if (*l_name == DELETED_FLAG)
 457                 *l_name = '\0';
 458         else if (*l_name == aRING)
 459                 *l_name = DELETED_FLAG;
 460         downcase(l_name);
 461
 462         /* Return the real directory entry */
 463         *retdent = realdent;
 464
 465         if (slotptr2) {
 466                 memcpy(get_dentfromdir_block, get_vfatname_block,
 467                         mydata->clust_size * mydata->sect_size);
 468                 cur_position = (__u8 *)realdent - get_vfatname_block;
 469                 *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
 470         }
 471
 472         return 0;
 473 }
 474
 475 #endif
 476
 477 /*
 478  * Set the entry at index 'entry' in a FAT (16/32) table.
 479  */
 480 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 481 {
 482         __u32 bufnum, offset;
 483
 484         switch (mydata->fatsize) {
 485         case 32:
 486                 bufnum = entry / FAT32BUFSIZE;
 487                 offset = entry - bufnum * FAT32BUFSIZE;
 488                 break;
 489         case 16:
 490                 bufnum = entry / FAT16BUFSIZE;
 491                 offset = entry - bufnum * FAT16BUFSIZE;
 492                 break;
 493         default:
 494                 /* Unsupported FAT size */
 495                 return -1;
 496         }
 497
 498         /* Read a new block of FAT entries into the cache. */
 499         if (bufnum != mydata->fatbufnum) {
 500                 int getsize = FATBUFBLOCKS;
 501                 __u8 *bufptr = mydata->fatbuf;
 502                 __u32 fatlength = mydata->fatlength;
 503                 __u32 startblock = bufnum * FATBUFBLOCKS;
 504
 505                 fatlength *= mydata->sect_size;
 506                 startblock += mydata->fat_sect;
 507
 508                 if (getsize > fatlength)
 509                         getsize = fatlength;
 510
 511                 if (mydata->fatbufnum != -1) {
 512                         if (flush_fat_buffer(mydata) < 0)
 513                                 return -1;
 514                 }
 515
 516                 if (disk_read(startblock, getsize, bufptr) < 0) {
 517                         debug("Error reading FAT blocks\n");
 518                         return -1;
 519                 }
 520                 mydata->fatbufnum = bufnum;
 521         }
 522
 523         /* Set the actual entry */
 524         switch (mydata->fatsize) {
 525         case 32:
 526                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 527                 break;
 528         case 16:
 529                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 530                 break;
 531         default:
 532                 return -1;
 533         }
 534
 535         return 0;
 536 }
 537
 538 /*
 539  * Determine the entry value at index 'entry' in a FAT (16/32) table
 540  */
 541 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 542 {
 543         __u32 next_fat, next_entry = entry + 1;
 544
 545         while (1) {
 546                 next_fat = get_fatent_value(mydata, next_entry);
 547                 if (next_fat == 0) {
 548                         set_fatent_value(mydata, entry, next_entry);
 549                         break;
 550                 }
 551                 next_entry++;
 552         }
 553         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 554                mydata->fatsize, entry, next_entry);
 555
 556         return next_entry;
 557 }
 558
 559 /*
 560  * Write at most 'size' bytes from 'buffer' into the specified cluster.
 561  * Return 0 on success, -1 otherwise.
 562  */
 563 static int
 564 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 565              unsigned long size)
 566 {
 567         int idx = 0;
 568         __u32 startsect;
 569
 570         if (clustnum > 0)
 571                 startsect = mydata->data_begin +
 572                                 clustnum * mydata->clust_size;
 573         else
 574                 startsect = mydata->rootdir_sect;
 575
 576         debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 577
 578         if (disk_write(startsect, size / mydata->sect_size, buffer) < 0) {
 579                 debug("Error writing data\n");
 580                 return -1;
 581         }
 582
 583         if (size % mydata->sect_size) {
 584                 __u8 tmpbuf[mydata->sect_size];
 585
 586                 idx = size / mydata->sect_size;
 587                 buffer += idx * mydata->sect_size;
 588                 memcpy(tmpbuf, buffer, size % mydata->sect_size);
 589
 590                 if (disk_write(startsect + idx, 1, tmpbuf) < 0) {
 591                         debug("Error writing data\n");
 592                         return -1;
 593                 }
 594
 595                 return 0;
 596         }
 597
 598         return 0;
 599 }
 600
 601 /*
 602  * Find the first empty cluster
 603  */
 604 static int find_empty_cluster(fsdata *mydata)
 605 {
 606         __u32 fat_val, entry = 3;
 607
 608         while (1) {
 609                 fat_val = get_fatent_value(mydata, entry);
 610                 if (fat_val == 0)
 611                         break;
 612                 entry++;
 613         }
 614
 615         return entry;
 616 }
 617
 618 /*
 619  * Write directory entries in 'get_dentfromdir_block' to block device
 620  */
 621 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
 622 {
 623         int dir_newclust = 0;
 624
 625         if (set_cluster(mydata, dir_curclust,
 626                     get_dentfromdir_block,
 627                     mydata->clust_size * mydata->sect_size) != 0) {
 628                 printf("error: wrinting directory entry\n");
 629                 return;
 630         }
 631         dir_newclust = find_empty_cluster(mydata);
 632         set_fatent_value(mydata, dir_curclust, dir_newclust);
 633         if (mydata->fatsize == 32)
 634                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 635         else if (mydata->fatsize == 16)
 636                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 637
 638         dir_curclust = dir_newclust;
 639
 640         if (flush_fat_buffer(mydata) < 0)
 641                 return;
 642
 643         memset(get_dentfromdir_block, 0x00,
 644                 mydata->clust_size * mydata->sect_size);
 645
 646         *dentptr = (dir_entry *) get_dentfromdir_block;
 647 }
 648
 649 /*
 650  * Set empty cluster from 'entry' to the end of a file
 651  */
 652 static int clear_fatent(fsdata *mydata, __u32 entry)
 653 {
 654         __u32 fat_val;
 655
 656         while (1) {
 657                 fat_val = get_fatent_value(mydata, entry);
 658                 if (fat_val != 0)
 659                         set_fatent_value(mydata, entry, 0);
 660                 else
 661                         break;
 662
 663                 if (fat_val == 0xfffffff || fat_val == 0xffff)
 664                         break;
 665
 666                 entry = fat_val;
 667         }
 668
 669         /* Flush fat buffer */
 670         if (flush_fat_buffer(mydata) < 0)
 671                 return -1;
 672
 673         return 0;
 674 }
 675
 676 /*
 677  * Write at most 'maxsize' bytes from 'buffer' into
 678  * the file associated with 'dentptr'
 679  * Return the number of bytes read or -1 on fatal errors.
 680  */
 681 static int
 682 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
 683               unsigned long maxsize)
 684 {
 685         unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
 686         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 687         __u32 curclust = START(dentptr);
 688         __u32 endclust = 0, newclust = 0;
 689         unsigned long actsize;
 690
 691         debug("Filesize: %ld bytes\n", filesize);
 692
 693         if (maxsize > 0 && filesize > maxsize)
 694                 filesize = maxsize;
 695
 696         debug("%ld bytes\n", filesize);
 697
 698         actsize = bytesperclust;
 699         endclust = curclust;
 700         do {
 701                 /* search for consecutive clusters */
 702                 while (actsize < filesize) {
 703                         newclust = determine_fatent(mydata, endclust);
 704
 705                         if ((newclust - 1) != endclust)
 706                                 goto getit;
 707
 708                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 709                                 debug("curclust: 0x%x\n", newclust);
 710                                 debug("Invalid FAT entry\n");
 711                                 return gotsize;
 712                         }
 713                         endclust = newclust;
 714                         actsize += bytesperclust;
 715                 }
 716                 /* actsize >= file size */
 717                 actsize -= bytesperclust;
 718                 /* set remaining clusters */
 719                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 720                         debug("error: writing cluster\n");
 721                         return -1;
 722                 }
 723
 724                 /* set remaining bytes */
 725                 gotsize += (int)actsize;
 726                 filesize -= actsize;
 727                 buffer += actsize;
 728                 actsize = filesize;
 729
 730                 if (set_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
 731                         debug("error: writing cluster\n");
 732                         return -1;
 733                 }
 734                 gotsize += actsize;
 735
 736                 /* Mark end of file in FAT */
 737                 if (mydata->fatsize == 16)
 738                         newclust = 0xffff;
 739                 else if (mydata->fatsize == 32)
 740                         newclust = 0xfffffff;
 741                 set_fatent_value(mydata, endclust, newclust);
 742
 743                 return gotsize;
 744 getit:
 745                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 746                         debug("error: writing cluster\n");
 747                         return -1;
 748                 }
 749                 gotsize += (int)actsize;
 750                 filesize -= actsize;
 751                 buffer += actsize;
 752
 753                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 754                         debug("curclust: 0x%x\n", curclust);
 755                         debug("Invalid FAT entry\n");
 756                         return gotsize;
 757                 }
 758                 actsize = bytesperclust;
 759                 curclust = endclust = newclust;
 760         } while (1);
 761 }
 762
 763 /*
 764  * Fill dir_entry
 765  */
 766 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 767         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 768 {
 769         if (mydata->fatsize == 32)
 770                 dentptr->starthi =
 771                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 772         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 773         dentptr->size = cpu_to_le32(size);
 774
 775         dentptr->attr = attr;
 776
 777         set_name(dentptr, filename);
 778 }
 779
 780 /*
 781  * Check whether adding a file makes the file system to
 782  * exceed the size of the block device
 783  * Return -1 when overflow occurs, otherwise return 0
 784  */
 785 static int check_overflow(fsdata *mydata, __u32 clustnum, unsigned long size)
 786 {
 787         __u32 startsect, sect_num;
 788
 789         if (clustnum > 0) {
 790                 startsect = mydata->data_begin +
 791                                 clustnum * mydata->clust_size;
 792         } else {
 793                 startsect = mydata->rootdir_sect;
 794         }
 795
 796         sect_num = size / mydata->sect_size;
 797         if (size % mydata->sect_size)
 798                 sect_num++;
 799
 800         if (startsect + sect_num > total_sector)
 801                 return -1;
 802
 803         return 0;
 804 }
 805
 806 /*
 807  * Check if adding several entries exceed one cluster boundary
 808  */
 809 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
 810 {
 811         int cur_position;
 812
 813         cur_position = (__u8 *)dentptr - get_dentfromdir_block;
 814
 815         if (cur_position >= mydata->clust_size * mydata->sect_size)
 816                 return 1;
 817         else
 818                 return 0;
 819 }
 820
 821 static dir_entry *empty_dentptr;
 822 /*
 823  * Find a directory entry based on filename or start cluster number
 824  * If the directory entry is not found,
 825  * the new position for writing a directory entry will be returned
 826  */
 827 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
 828         char *filename, dir_entry *retdent, __u32 start)
 829 {
 830         __u16 prevcksum = 0xffff;
 831         __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
 832
 833         debug("get_dentfromdir: %s\n", filename);
 834
 835         while (1) {
 836                 dir_entry *dentptr;
 837
 838                 int i;
 839
 840                 if (get_cluster(mydata, curclust, get_dentfromdir_block,
 841                             mydata->clust_size * mydata->sect_size) != 0) {
 842                         printf("Error: reading directory block\n");
 843                         return NULL;
 844                 }
 845
 846                 dentptr = (dir_entry *)get_dentfromdir_block;
 847
 848                 dir_curclust = curclust;
 849
 850                 for (i = 0; i < DIRENTSPERCLUST; i++) {
 851                         char s_name[14], l_name[VFAT_MAXLEN_BYTES];
 852
 853                         l_name[0] = '\0';
 854                         if (dentptr->name[0] == DELETED_FLAG) {
 855                                 dentptr++;
 856                                 if (is_next_clust(mydata, dentptr))
 857                                         break;
 858                                 continue;
 859                         }
 860                         if ((dentptr->attr & ATTR_VOLUME)) {
 861 #ifdef CONFIG_SUPPORT_VFAT
 862                                 if ((dentptr->attr & ATTR_VFAT) &&
 863                                     (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
 864                                         prevcksum =
 865                                         ((dir_slot *)dentptr)->alias_checksum;
 866                                         get_long_file_name(mydata, curclust,
 867                                                      get_dentfromdir_block,
 868                                                      &dentptr, l_name);
 869                                         debug("vfatname: |%s|\n", l_name);
 870                                 } else
 871 #endif
 872                                 {
 873                                         /* Volume label or VFAT entry */
 874                                         dentptr++;
 875                                         if (is_next_clust(mydata, dentptr))
 876                                                 break;
 877                                         continue;
 878                                 }
 879                         }
 880                         if (dentptr->name[0] == 0) {
 881                                 debug("Dentname == NULL - %d\n", i);
 882                                 empty_dentptr = dentptr;
 883                                 return NULL;
 884                         }
 885
 886                         get_name(dentptr, s_name);
 887
 888                         if (strcmp(filename, s_name)
 889                             && strcmp(filename, l_name)) {
 890                                 debug("Mismatch: |%s|%s|\n",
 891                                         s_name, l_name);
 892                                 dentptr++;
 893                                 if (is_next_clust(mydata, dentptr))
 894                                         break;
 895                                 continue;
 896                         }
 897
 898                         memcpy(retdent, dentptr, sizeof(dir_entry));
 899
 900                         debug("DentName: %s", s_name);
 901                         debug(", start: 0x%x", START(dentptr));
 902                         debug(", size:  0x%x %s\n",
 903                               FAT2CPU32(dentptr->size),
 904                               (dentptr->attr & ATTR_DIR) ?
 905                               "(DIR)" : "");
 906
 907                         return dentptr;
 908                 }
 909
 910                 curclust = get_fatent_value(mydata, dir_curclust);
 911                 if ((curclust >= 0xffffff8) || (curclust >= 0xfff8)) {
 912                         empty_dentptr = dentptr;
 913                         return NULL;
 914                 }
 915                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 916                         debug("curclust: 0x%x\n", curclust);
 917                         debug("Invalid FAT entry\n");
 918                         return NULL;
 919                 }
 920         }
 921
 922         return NULL;
 923 }
 924
 925 static int do_fat_write(const char *filename, void *buffer,
 926         unsigned long size)
 927 {
 928         dir_entry *dentptr, *retdent;
 929         dir_slot *slotptr;
 930         __u32 startsect;
 931         __u32 start_cluster;
 932         boot_sector bs;
 933         volume_info volinfo;
 934         fsdata datablock;
 935         fsdata *mydata = &datablock;
 936         int cursect;
 937         int root_cluster, ret = -1, name_len;
 938         char l_filename[VFAT_MAXLEN_BYTES];
 939         int write_size = size;
 940
 941         dir_curclust = 0;
 942
 943         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 944                 debug("error: reading boot sector\n");
 945                 return -1;
 946         }
 947
 948         total_sector = bs.total_sect;
 949         if (total_sector == 0)
 950                 total_sector = part_size;
 951
 952         root_cluster = bs.root_cluster;
 953
 954         if (mydata->fatsize == 32)
 955                 mydata->fatlength = bs.fat32_length;
 956         else
 957                 mydata->fatlength = bs.fat_length;
 958
 959         mydata->fat_sect = bs.reserved;
 960
 961         cursect = mydata->rootdir_sect
 962                 = mydata->fat_sect + mydata->fatlength * bs.fats;
 963         num_of_fats = bs.fats;
 964
 965         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
 966         mydata->clust_size = bs.cluster_size;
 967
 968         if (mydata->fatsize == 32) {
 969                 mydata->data_begin = mydata->rootdir_sect -
 970                                         (mydata->clust_size * 2);
 971         } else {
 972                 int rootdir_size;
 973
 974                 rootdir_size = ((bs.dir_entries[1]  * (int)256 +
 975                                  bs.dir_entries[0]) *
 976                                  sizeof(dir_entry)) /
 977                                  mydata->sect_size;
 978                 mydata->data_begin = mydata->rootdir_sect +
 979                                         rootdir_size -
 980                                         (mydata->clust_size * 2);
 981         }
 982
 983         mydata->fatbufnum = -1;
 984         mydata->fatbuf = malloc(FATBUFSIZE);
 985         if (mydata->fatbuf == NULL) {
 986                 debug("Error: allocating memory\n");
 987                 return -1;
 988         }
 989
 990         if (disk_read(cursect,
 991                 (mydata->fatsize == 32) ?
 992                 (mydata->clust_size) :
 993                 PREFETCH_BLOCKS, do_fat_read_block) < 0) {
 994                 debug("Error: reading rootdir block\n");
 995                 goto exit;
 996         }
 997         dentptr = (dir_entry *) do_fat_read_block;
 998
 999         name_len = strlen(filename);
1000         if (name_len >= VFAT_MAXLEN_BYTES)
1001                 name_len = VFAT_MAXLEN_BYTES - 1;
1002
1003         memcpy(l_filename, filename, name_len);
1004         l_filename[name_len] = 0; /* terminate the string */
1005         downcase(l_filename);
1006
1007         startsect = mydata->rootdir_sect;
1008         retdent = find_directory_entry(mydata, startsect,
1009                                 l_filename, dentptr, 0);
1010         if (retdent) {
1011                 /* Update file size and start_cluster in a directory entry */
1012                 retdent->size = cpu_to_le32(size);
1013                 start_cluster = FAT2CPU16(retdent->start);
1014                 if (mydata->fatsize == 32)
1015                         start_cluster |=
1016                                 (FAT2CPU16(retdent->starthi) << 16);
1017
1018                 ret = check_overflow(mydata, start_cluster, size);
1019                 if (ret) {
1020                         printf("Error: %ld overflow\n", size);
1021                         goto exit;
1022                 }
1023
1024                 ret = clear_fatent(mydata, start_cluster);
1025                 if (ret) {
1026                         printf("Error: clearing FAT entries\n");
1027                         goto exit;
1028                 }
1029
1030                 ret = set_contents(mydata, retdent, buffer, size);
1031                 if (ret < 0) {
1032                         printf("Error: writing contents\n");
1033                         goto exit;
1034                 }
1035                 write_size = ret;
1036                 debug("attempt to write 0x%x bytes\n", write_size);
1037
1038                 /* Flush fat buffer */
1039                 ret = flush_fat_buffer(mydata);
1040                 if (ret) {
1041                         printf("Error: flush fat buffer\n");
1042                         goto exit;
1043                 }
1044
1045                 /* Write directory table to device */
1046                 ret = set_cluster(mydata, dir_curclust,
1047                             get_dentfromdir_block,
1048                             mydata->clust_size * mydata->sect_size);
1049                 if (ret) {
1050                         printf("Error: writing directory entry\n");
1051                         goto exit;
1052                 }
1053         } else {
1054                 slotptr = (dir_slot *)empty_dentptr;
1055
1056                 /* Set short name to set alias checksum field in dir_slot */
1057                 set_name(empty_dentptr, filename);
1058                 fill_dir_slot(mydata, &empty_dentptr, filename);
1059
1060                 ret = start_cluster = find_empty_cluster(mydata);
1061                 if (ret < 0) {
1062                         printf("Error: finding empty cluster\n");
1063                         goto exit;
1064                 }
1065
1066                 ret = check_overflow(mydata, start_cluster, size);
1067                 if (ret) {
1068                         printf("Error: %ld overflow\n", size);
1069                         goto exit;
1070                 }
1071
1072                 /* Set attribute as archieve for regular file */
1073                 fill_dentry(mydata, empty_dentptr, filename,
1074                         start_cluster, size, 0x20);
1075
1076                 ret = set_contents(mydata, empty_dentptr, buffer, size);
1077                 if (ret < 0) {
1078                         printf("Error: writing contents\n");
1079                         goto exit;
1080                 }
1081                 write_size = ret;
1082                 debug("attempt to write 0x%x bytes\n", write_size);
1083
1084                 /* Flush fat buffer */
1085                 ret = flush_fat_buffer(mydata);
1086                 if (ret) {
1087                         printf("Error: flush fat buffer\n");
1088                         goto exit;
1089                 }
1090
1091                 /* Write directory table to device */
1092                 ret = set_cluster(mydata, dir_curclust,
1093                             get_dentfromdir_block,
1094                             mydata->clust_size * mydata->sect_size);
1095                 if (ret) {
1096                         printf("Error: writing directory entry\n");
1097                         goto exit;
1098                 }
1099         }
1100
1101 exit:
1102         free(mydata->fatbuf);
1103         return ret < 0 ? ret : write_size;
1104 }
1105
1106 int file_fat_write(const char *filename, void *buffer, unsigned long maxsize)
1107 {
1108         printf("writing %s\n", filename);
1109         return do_fat_write(filename, buffer, maxsize);
1110 }