git.sur5r.net Git - u-boot/blob - fs/fat/fat_write.c

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