fs/fat/fat_write.c

   1 /*
   2  * fat_write.c
   3  *
   4  * R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <command.h>
  11 #include <config.h>
  12 #include <fat.h>
  13 #include <asm/byteorder.h>
  14 #include <part.h>
  15 #include <linux/ctype.h>
  16 #include <div64.h>
  17 #include <linux/math64.h>
  18 #include "fat.c"
  19
  20 static void uppercase(char *str, int len)
  21 {
  22         int i;
  23
  24         for (i = 0; i < len; i++) {
  25                 *str = toupper(*str);
  26                 str++;
  27         }
  28 }
  29
  30 static int total_sector;
  31 static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
  32 {
  33         ulong ret;
  34
  35         if (!cur_dev)
  36                 return -1;
  37
  38         if (cur_part_info.start + block + nr_blocks >
  39                 cur_part_info.start + total_sector) {
  40                 printf("error: overflow occurs\n");
  41                 return -1;
  42         }
  43
  44         ret = blk_dwrite(cur_dev, cur_part_info.start + block, nr_blocks, buf);
  45         if (nr_blocks && ret == 0)
  46                 return -1;
  47
  48         return ret;
  49 }
  50
  51 /*
  52  * Set short name in directory entry
  53  */
  54 static void set_name(dir_entry *dirent, const char *filename)
  55 {
  56         char s_name[VFAT_MAXLEN_BYTES];
  57         char *period;
  58         int period_location, len, i, ext_num;
  59
  60         if (filename == NULL)
  61                 return;
  62
  63         len = strlen(filename);
  64         if (len == 0)
  65                 return;
  66
  67         strcpy(s_name, filename);
  68         uppercase(s_name, len);
  69
  70         period = strchr(s_name, '.');
  71         if (period == NULL) {
  72                 period_location = len;
  73                 ext_num = 0;
  74         } else {
  75                 period_location = period - s_name;
  76                 ext_num = len - period_location - 1;
  77         }
  78
  79         /* Pad spaces when the length of file name is shorter than eight */
  80         if (period_location < 8) {
  81                 memcpy(dirent->name, s_name, period_location);
  82                 for (i = period_location; i < 8; i++)
  83                         dirent->name[i] = ' ';
  84         } else if (period_location == 8) {
  85                 memcpy(dirent->name, s_name, period_location);
  86         } else {
  87                 memcpy(dirent->name, s_name, 6);
  88                 dirent->name[6] = '~';
  89                 dirent->name[7] = '1';
  90         }
  91
  92         if (ext_num < 3) {
  93                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
  94                 for (i = ext_num; i < 3; i++)
  95                         dirent->ext[i] = ' ';
  96         } else
  97                 memcpy(dirent->ext, s_name + period_location + 1, 3);
  98
  99         debug("name : %s\n", dirent->name);
 100         debug("ext : %s\n", dirent->ext);
 101 }
 102
 103 static __u8 num_of_fats;
 104 /*
 105  * Write fat buffer into block device
 106  */
 107 static int flush_dirty_fat_buffer(fsdata *mydata)
 108 {
 109         int getsize = FATBUFBLOCKS;
 110         __u32 fatlength = mydata->fatlength;
 111         __u8 *bufptr = mydata->fatbuf;
 112         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 113
 114         debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum,
 115               (int)mydata->fat_dirty);
 116
 117         if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1))
 118                 return 0;
 119
 120         startblock += mydata->fat_sect;
 121
 122         if (getsize > fatlength)
 123                 getsize = fatlength;
 124
 125         /* Write FAT buf */
 126         if (disk_write(startblock, getsize, bufptr) < 0) {
 127                 debug("error: writing FAT blocks\n");
 128                 return -1;
 129         }
 130
 131         if (num_of_fats == 2) {
 132                 /* Update corresponding second FAT blocks */
 133                 startblock += mydata->fatlength;
 134                 if (disk_write(startblock, getsize, bufptr) < 0) {
 135                         debug("error: writing second FAT blocks\n");
 136                         return -1;
 137                 }
 138         }
 139         mydata->fat_dirty = 0;
 140
 141         return 0;
 142 }
 143
 144 /*
 145  * Get the entry at index 'entry' in a FAT (12/16/32) table.
 146  * On failure 0x00 is returned.
 147  * When bufnum is changed, write back the previous fatbuf to the disk.
 148  */
 149 static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
 150 {
 151         __u32 bufnum;
 152         __u32 off16, offset;
 153         __u32 ret = 0x00;
 154         __u16 val1, val2;
 155
 156         if (CHECK_CLUST(entry, mydata->fatsize)) {
 157                 printf("Error: Invalid FAT entry: 0x%08x\n", entry);
 158                 return ret;
 159         }
 160
 161         switch (mydata->fatsize) {
 162         case 32:
 163                 bufnum = entry / FAT32BUFSIZE;
 164                 offset = entry - bufnum * FAT32BUFSIZE;
 165                 break;
 166         case 16:
 167                 bufnum = entry / FAT16BUFSIZE;
 168                 offset = entry - bufnum * FAT16BUFSIZE;
 169                 break;
 170         case 12:
 171                 bufnum = entry / FAT12BUFSIZE;
 172                 offset = entry - bufnum * FAT12BUFSIZE;
 173                 break;
 174
 175         default:
 176                 /* Unsupported FAT size */
 177                 return ret;
 178         }
 179
 180         debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
 181                mydata->fatsize, entry, entry, offset, offset);
 182
 183         /* Read a new block of FAT entries into the cache. */
 184         if (bufnum != mydata->fatbufnum) {
 185                 int getsize = FATBUFBLOCKS;
 186                 __u8 *bufptr = mydata->fatbuf;
 187                 __u32 fatlength = mydata->fatlength;
 188                 __u32 startblock = bufnum * FATBUFBLOCKS;
 189
 190                 if (getsize > fatlength)
 191                         getsize = fatlength;
 192
 193                 startblock += mydata->fat_sect; /* Offset from start of disk */
 194
 195                 /* Write back the fatbuf to the disk */
 196                 if (flush_dirty_fat_buffer(mydata) < 0)
 197                         return -1;
 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         __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
 331         dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
 332         __u8 counter = 0, checksum;
 333         int idx = 0, ret;
 334
 335         /* Get short file name checksum value */
 336         checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
 337
 338         do {
 339                 memset(slotptr, 0x00, sizeof(dir_slot));
 340                 ret = str2slot(slotptr, l_name, &idx);
 341                 slotptr->id = ++counter;
 342                 slotptr->attr = ATTR_VFAT;
 343                 slotptr->alias_checksum = checksum;
 344                 slotptr++;
 345         } while (ret == 0);
 346
 347         slotptr--;
 348         slotptr->id |= LAST_LONG_ENTRY_MASK;
 349
 350         while (counter >= 1) {
 351                 if (is_next_clust(mydata, *dentptr)) {
 352                         /* A new cluster is allocated for directory table */
 353                         flush_dir_table(mydata, dentptr);
 354                 }
 355                 memcpy(*dentptr, slotptr, sizeof(dir_slot));
 356                 (*dentptr)++;
 357                 slotptr--;
 358                 counter--;
 359         }
 360
 361         if (is_next_clust(mydata, *dentptr)) {
 362                 /* A new cluster is allocated for directory table */
 363                 flush_dir_table(mydata, dentptr);
 364         }
 365 }
 366
 367 static __u32 dir_curclust;
 368
 369 /*
 370  * Extract the full long filename starting at 'retdent' (which is really
 371  * a slot) into 'l_name'. If successful also copy the real directory entry
 372  * into 'retdent'
 373  * If additional adjacent cluster for directory entries is read into memory,
 374  * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
 375  * the location of the real directory entry is returned by 'retdent'
 376  * Return 0 on success, -1 otherwise.
 377  */
 378 static int
 379 get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
 380               dir_entry **retdent, char *l_name)
 381 {
 382         dir_entry *realdent;
 383         dir_slot *slotptr = (dir_slot *)(*retdent);
 384         dir_slot *slotptr2 = NULL;
 385         __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
 386                                                         PREFETCH_BLOCKS :
 387                                                         mydata->clust_size);
 388         __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
 389         int idx = 0, cur_position = 0;
 390
 391         if (counter > VFAT_MAXSEQ) {
 392                 debug("Error: VFAT name is too long\n");
 393                 return -1;
 394         }
 395
 396         while ((__u8 *)slotptr < buflimit) {
 397                 if (counter == 0)
 398                         break;
 399                 if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
 400                         return -1;
 401                 slotptr++;
 402                 counter--;
 403         }
 404
 405         if ((__u8 *)slotptr >= buflimit) {
 406                 if (curclust == 0)
 407                         return -1;
 408                 curclust = get_fatent_value(mydata, dir_curclust);
 409                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 410                         debug("curclust: 0x%x\n", curclust);
 411                         printf("Invalid FAT entry\n");
 412                         return -1;
 413                 }
 414
 415                 dir_curclust = curclust;
 416
 417                 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
 418                                 mydata->clust_size * mydata->sect_size) != 0) {
 419                         debug("Error: reading directory block\n");
 420                         return -1;
 421                 }
 422
 423                 slotptr2 = (dir_slot *)get_contents_vfatname_block;
 424                 while (counter > 0) {
 425                         if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
 426                             & 0xff) != counter)
 427                                 return -1;
 428                         slotptr2++;
 429                         counter--;
 430                 }
 431
 432                 /* Save the real directory entry */
 433                 realdent = (dir_entry *)slotptr2;
 434                 while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
 435                         slotptr2--;
 436                         slot2str(slotptr2, l_name, &idx);
 437                 }
 438         } else {
 439                 /* Save the real directory entry */
 440                 realdent = (dir_entry *)slotptr;
 441         }
 442
 443         do {
 444                 slotptr--;
 445                 if (slot2str(slotptr, l_name, &idx))
 446                         break;
 447         } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
 448
 449         l_name[idx] = '\0';
 450         if (*l_name == DELETED_FLAG)
 451                 *l_name = '\0';
 452         else if (*l_name == aRING)
 453                 *l_name = DELETED_FLAG;
 454         downcase(l_name);
 455
 456         /* Return the real directory entry */
 457         *retdent = realdent;
 458
 459         if (slotptr2) {
 460                 memcpy(get_dentfromdir_block, get_contents_vfatname_block,
 461                         mydata->clust_size * mydata->sect_size);
 462                 cur_position = (__u8 *)realdent - get_contents_vfatname_block;
 463                 *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
 464         }
 465
 466         return 0;
 467 }
 468
 469 /*
 470  * Set the entry at index 'entry' in a FAT (12/16/32) table.
 471  */
 472 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 473 {
 474         __u32 bufnum, offset, off16;
 475         __u16 val1, val2;
 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         case 12:
 487                 bufnum = entry / FAT12BUFSIZE;
 488                 offset = entry - bufnum * FAT12BUFSIZE;
 489                 break;
 490         default:
 491                 /* Unsupported FAT size */
 492                 return -1;
 493         }
 494
 495         /* Read a new block of FAT entries into the cache. */
 496         if (bufnum != mydata->fatbufnum) {
 497                 int getsize = FATBUFBLOCKS;
 498                 __u8 *bufptr = mydata->fatbuf;
 499                 __u32 fatlength = mydata->fatlength;
 500                 __u32 startblock = bufnum * FATBUFBLOCKS;
 501
 502                 fatlength *= mydata->sect_size;
 503                 startblock += mydata->fat_sect;
 504
 505                 if (getsize > fatlength)
 506                         getsize = fatlength;
 507
 508                 if (flush_dirty_fat_buffer(mydata) < 0)
 509                         return -1;
 510
 511                 if (disk_read(startblock, getsize, bufptr) < 0) {
 512                         debug("Error reading FAT blocks\n");
 513                         return -1;
 514                 }
 515                 mydata->fatbufnum = bufnum;
 516         }
 517
 518         /* Mark as dirty */
 519         mydata->fat_dirty = 1;
 520
 521         /* Set the actual entry */
 522         switch (mydata->fatsize) {
 523         case 32:
 524                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 525                 break;
 526         case 16:
 527                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 528                 break;
 529         case 12:
 530                 off16 = (offset * 3) / 4;
 531
 532                 switch (offset & 0x3) {
 533                 case 0:
 534                         val1 = cpu_to_le16(entry_value) & 0xfff;
 535                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
 536                         ((__u16 *)mydata->fatbuf)[off16] |= val1;
 537                         break;
 538                 case 1:
 539                         val1 = cpu_to_le16(entry_value) & 0xf;
 540                         val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
 541
 542                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
 543                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
 544
 545                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
 546                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 547                         break;
 548                 case 2:
 549                         val1 = cpu_to_le16(entry_value) & 0xff;
 550                         val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
 551
 552                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
 553                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
 554
 555                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
 556                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 557                         break;
 558                 case 3:
 559                         val1 = cpu_to_le16(entry_value) & 0xfff;
 560                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
 561                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
 562                         break;
 563                 default:
 564                         break;
 565                 }
 566
 567                 break;
 568         default:
 569                 return -1;
 570         }
 571
 572         return 0;
 573 }
 574
 575 /*
 576  * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
 577  * and link it to 'entry'. EOC marker is not set on returned entry.
 578  */
 579 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 580 {
 581         __u32 next_fat, next_entry = entry + 1;
 582
 583         while (1) {
 584                 next_fat = get_fatent_value(mydata, next_entry);
 585                 if (next_fat == 0) {
 586                         /* found free entry, link to entry */
 587                         set_fatent_value(mydata, entry, next_entry);
 588                         break;
 589                 }
 590                 next_entry++;
 591         }
 592         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 593                mydata->fatsize, entry, next_entry);
 594
 595         return next_entry;
 596 }
 597
 598 /*
 599  * Write at most 'size' bytes from 'buffer' into the specified cluster.
 600  * Return 0 on success, -1 otherwise.
 601  */
 602 static int
 603 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 604              unsigned long size)
 605 {
 606         __u32 idx = 0;
 607         __u32 startsect;
 608         int ret;
 609
 610         if (clustnum > 0)
 611                 startsect = mydata->data_begin +
 612                                 clustnum * mydata->clust_size;
 613         else
 614                 startsect = mydata->rootdir_sect;
 615
 616         debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 617
 618         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 619                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 620
 621                 printf("FAT: Misaligned buffer address (%p)\n", buffer);
 622
 623                 while (size >= mydata->sect_size) {
 624                         memcpy(tmpbuf, buffer, mydata->sect_size);
 625                         ret = disk_write(startsect++, 1, tmpbuf);
 626                         if (ret != 1) {
 627                                 debug("Error writing data (got %d)\n", ret);
 628                                 return -1;
 629                         }
 630
 631                         buffer += mydata->sect_size;
 632                         size -= mydata->sect_size;
 633                 }
 634         } else if (size >= mydata->sect_size) {
 635                 idx = size / mydata->sect_size;
 636                 ret = disk_write(startsect, idx, buffer);
 637                 if (ret != idx) {
 638                         debug("Error writing data (got %d)\n", ret);
 639                         return -1;
 640                 }
 641
 642                 startsect += idx;
 643                 idx *= mydata->sect_size;
 644                 buffer += idx;
 645                 size -= idx;
 646         }
 647
 648         if (size) {
 649                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 650
 651                 memcpy(tmpbuf, buffer, size);
 652                 ret = disk_write(startsect, 1, tmpbuf);
 653                 if (ret != 1) {
 654                         debug("Error writing data (got %d)\n", ret);
 655                         return -1;
 656                 }
 657         }
 658
 659         return 0;
 660 }
 661
 662 /*
 663  * Find the first empty cluster
 664  */
 665 static int find_empty_cluster(fsdata *mydata)
 666 {
 667         __u32 fat_val, entry = 3;
 668
 669         while (1) {
 670                 fat_val = get_fatent_value(mydata, entry);
 671                 if (fat_val == 0)
 672                         break;
 673                 entry++;
 674         }
 675
 676         return entry;
 677 }
 678
 679 /*
 680  * Write directory entries in 'get_dentfromdir_block' to block device
 681  */
 682 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
 683 {
 684         int dir_newclust = 0;
 685
 686         if (set_cluster(mydata, dir_curclust,
 687                     get_dentfromdir_block,
 688                     mydata->clust_size * mydata->sect_size) != 0) {
 689                 printf("error: wrinting directory entry\n");
 690                 return;
 691         }
 692         dir_newclust = find_empty_cluster(mydata);
 693         set_fatent_value(mydata, dir_curclust, dir_newclust);
 694         if (mydata->fatsize == 32)
 695                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 696         else if (mydata->fatsize == 16)
 697                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 698         else if (mydata->fatsize == 12)
 699                 set_fatent_value(mydata, dir_newclust, 0xff8);
 700
 701         dir_curclust = dir_newclust;
 702
 703         if (flush_dirty_fat_buffer(mydata) < 0)
 704                 return;
 705
 706         memset(get_dentfromdir_block, 0x00,
 707                 mydata->clust_size * mydata->sect_size);
 708
 709         *dentptr = (dir_entry *) get_dentfromdir_block;
 710 }
 711
 712 /*
 713  * Set empty cluster from 'entry' to the end of a file
 714  */
 715 static int clear_fatent(fsdata *mydata, __u32 entry)
 716 {
 717         __u32 fat_val;
 718
 719         while (!CHECK_CLUST(entry, mydata->fatsize)) {
 720                 fat_val = get_fatent_value(mydata, entry);
 721                 if (fat_val != 0)
 722                         set_fatent_value(mydata, entry, 0);
 723                 else
 724                         break;
 725
 726                 entry = fat_val;
 727         }
 728
 729         /* Flush fat buffer */
 730         if (flush_dirty_fat_buffer(mydata) < 0)
 731                 return -1;
 732
 733         return 0;
 734 }
 735
 736 /*
 737  * Write at most 'maxsize' bytes from 'buffer' into
 738  * the file associated with 'dentptr'
 739  * Update the number of bytes written in *gotsize and return 0
 740  * or return -1 on fatal errors.
 741  */
 742 static int
 743 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
 744               loff_t maxsize, loff_t *gotsize)
 745 {
 746         loff_t filesize = FAT2CPU32(dentptr->size);
 747         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 748         __u32 curclust = START(dentptr);
 749         __u32 endclust = 0, newclust = 0;
 750         loff_t actsize;
 751
 752         *gotsize = 0;
 753         debug("Filesize: %llu bytes\n", filesize);
 754
 755         if (maxsize > 0 && filesize > maxsize)
 756                 filesize = maxsize;
 757
 758         debug("%llu bytes\n", filesize);
 759
 760         if (!curclust) {
 761                 if (filesize) {
 762                         debug("error: nonempty clusterless file!\n");
 763                         return -1;
 764                 }
 765                 return 0;
 766         }
 767
 768         actsize = bytesperclust;
 769         endclust = curclust;
 770         do {
 771                 /* search for consecutive clusters */
 772                 while (actsize < filesize) {
 773                         newclust = determine_fatent(mydata, endclust);
 774
 775                         if ((newclust - 1) != endclust)
 776                                 goto getit;
 777
 778                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 779                                 debug("newclust: 0x%x\n", newclust);
 780                                 debug("Invalid FAT entry\n");
 781                                 return 0;
 782                         }
 783                         endclust = newclust;
 784                         actsize += bytesperclust;
 785                 }
 786
 787                 /* set remaining bytes */
 788                 actsize = filesize;
 789                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 790                         debug("error: writing cluster\n");
 791                         return -1;
 792                 }
 793                 *gotsize += actsize;
 794
 795                 /* Mark end of file in FAT */
 796                 if (mydata->fatsize == 12)
 797                         newclust = 0xfff;
 798                 else if (mydata->fatsize == 16)
 799                         newclust = 0xffff;
 800                 else if (mydata->fatsize == 32)
 801                         newclust = 0xfffffff;
 802                 set_fatent_value(mydata, endclust, newclust);
 803
 804                 return 0;
 805 getit:
 806                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 807                         debug("error: writing cluster\n");
 808                         return -1;
 809                 }
 810                 *gotsize += actsize;
 811                 filesize -= actsize;
 812                 buffer += actsize;
 813
 814                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 815                         debug("newclust: 0x%x\n", newclust);
 816                         debug("Invalid FAT entry\n");
 817                         return 0;
 818                 }
 819                 actsize = bytesperclust;
 820                 curclust = endclust = newclust;
 821         } while (1);
 822 }
 823
 824 /*
 825  * Set start cluster in directory entry
 826  */
 827 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 828                                 __u32 start_cluster)
 829 {
 830         if (mydata->fatsize == 32)
 831                 dentptr->starthi =
 832                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 833         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 834 }
 835
 836 /*
 837  * Fill dir_entry
 838  */
 839 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 840         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 841 {
 842         set_start_cluster(mydata, dentptr, start_cluster);
 843         dentptr->size = cpu_to_le32(size);
 844
 845         dentptr->attr = attr;
 846
 847         set_name(dentptr, filename);
 848 }
 849
 850 /*
 851  * Check whether adding a file makes the file system to
 852  * exceed the size of the block device
 853  * Return -1 when overflow occurs, otherwise return 0
 854  */
 855 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 856 {
 857         __u32 startsect, sect_num, offset;
 858
 859         if (clustnum > 0) {
 860                 startsect = mydata->data_begin +
 861                                 clustnum * mydata->clust_size;
 862         } else {
 863                 startsect = mydata->rootdir_sect;
 864         }
 865
 866         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 867
 868         if (offset != 0)
 869                 sect_num++;
 870
 871         if (startsect + sect_num > cur_part_info.start + total_sector)
 872                 return -1;
 873         return 0;
 874 }
 875
 876 /*
 877  * Check if adding several entries exceed one cluster boundary
 878  */
 879 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
 880 {
 881         int cur_position;
 882
 883         cur_position = (__u8 *)dentptr - get_dentfromdir_block;
 884
 885         if (cur_position >= mydata->clust_size * mydata->sect_size)
 886                 return 1;
 887         else
 888                 return 0;
 889 }
 890
 891 static dir_entry *empty_dentptr;
 892 /*
 893  * Find a directory entry based on filename or start cluster number
 894  * If the directory entry is not found,
 895  * the new position for writing a directory entry will be returned
 896  */
 897 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
 898         char *filename, dir_entry *retdent, __u32 start)
 899 {
 900         __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
 901
 902         debug("get_dentfromdir: %s\n", filename);
 903
 904         while (1) {
 905                 dir_entry *dentptr;
 906
 907                 int i;
 908
 909                 if (get_cluster(mydata, curclust, get_dentfromdir_block,
 910                             mydata->clust_size * mydata->sect_size) != 0) {
 911                         printf("Error: reading directory block\n");
 912                         return NULL;
 913                 }
 914
 915                 dentptr = (dir_entry *)get_dentfromdir_block;
 916
 917                 dir_curclust = curclust;
 918
 919                 for (i = 0; i < DIRENTSPERCLUST; i++) {
 920                         char s_name[14], l_name[VFAT_MAXLEN_BYTES];
 921
 922                         l_name[0] = '\0';
 923                         if (dentptr->name[0] == DELETED_FLAG) {
 924                                 dentptr++;
 925                                 if (is_next_clust(mydata, dentptr))
 926                                         break;
 927                                 continue;
 928                         }
 929                         if ((dentptr->attr & ATTR_VOLUME)) {
 930                                 if (vfat_enabled &&
 931                                     (dentptr->attr & ATTR_VFAT) &&
 932                                     (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
 933                                         get_long_file_name(mydata, curclust,
 934                                                      get_dentfromdir_block,
 935                                                      &dentptr, l_name);
 936                                         debug("vfatname: |%s|\n", l_name);
 937                                 } else {
 938                                         /* Volume label or VFAT entry */
 939                                         dentptr++;
 940                                         if (is_next_clust(mydata, dentptr))
 941                                                 break;
 942                                         continue;
 943                                 }
 944                         }
 945                         if (dentptr->name[0] == 0) {
 946                                 debug("Dentname == NULL - %d\n", i);
 947                                 empty_dentptr = dentptr;
 948                                 return NULL;
 949                         }
 950
 951                         get_name(dentptr, s_name);
 952
 953                         if (strcmp(filename, s_name)
 954                             && strcmp(filename, l_name)) {
 955                                 debug("Mismatch: |%s|%s|\n",
 956                                         s_name, l_name);
 957                                 dentptr++;
 958                                 if (is_next_clust(mydata, dentptr))
 959                                         break;
 960                                 continue;
 961                         }
 962
 963                         memcpy(retdent, dentptr, sizeof(dir_entry));
 964
 965                         debug("DentName: %s", s_name);
 966                         debug(", start: 0x%x", START(dentptr));
 967                         debug(", size:  0x%x %s\n",
 968                               FAT2CPU32(dentptr->size),
 969                               (dentptr->attr & ATTR_DIR) ?
 970                               "(DIR)" : "");
 971
 972                         return dentptr;
 973                 }
 974
 975                 /*
 976                  * In FAT16/12, the root dir is locate before data area, shows
 977                  * in following:
 978                  * -------------------------------------------------------------
 979                  * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
 980                  * -------------------------------------------------------------
 981                  *
 982                  * As a result if curclust is in Root dir, it is a negative
 983                  * number or 0, 1.
 984                  *
 985                  */
 986                 if (mydata->fatsize != 32 && (int)curclust <= 1) {
 987                         /* Current clust is in root dir, set to next clust */
 988                         curclust++;
 989                         if ((int)curclust <= 1)
 990                                 continue;       /* continue to find */
 991
 992                         /* Reach the end of root dir */
 993                         empty_dentptr = dentptr;
 994                         return NULL;
 995                 }
 996
 997                 curclust = get_fatent_value(mydata, dir_curclust);
 998                 if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 999                         empty_dentptr = dentptr;
1000                         return NULL;
1001                 }
1002                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
1003                         debug("curclust: 0x%x\n", curclust);
1004                         debug("Invalid FAT entry\n");
1005                         return NULL;
1006                 }
1007         }
1008
1009         return NULL;
1010 }
1011
1012 static int do_fat_write(const char *filename, void *buffer, loff_t size,
1013                         loff_t *actwrite)
1014 {
1015         dir_entry *dentptr, *retdent;
1016         __u32 startsect;
1017         __u32 start_cluster;
1018         boot_sector bs;
1019         volume_info volinfo;
1020         fsdata datablock;
1021         fsdata *mydata = &datablock;
1022         int cursect;
1023         int ret = -1, name_len;
1024         char l_filename[VFAT_MAXLEN_BYTES];
1025
1026         *actwrite = size;
1027         dir_curclust = 0;
1028
1029         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
1030                 debug("error: reading boot sector\n");
1031                 return -1;
1032         }
1033
1034         total_sector = bs.total_sect;
1035         if (total_sector == 0)
1036                 total_sector = (int)cur_part_info.size; /* cast of lbaint_t */
1037
1038         if (mydata->fatsize == 32)
1039                 mydata->fatlength = bs.fat32_length;
1040         else
1041                 mydata->fatlength = bs.fat_length;
1042
1043         mydata->fat_sect = bs.reserved;
1044
1045         cursect = mydata->rootdir_sect
1046                 = mydata->fat_sect + mydata->fatlength * bs.fats;
1047         num_of_fats = bs.fats;
1048
1049         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
1050         mydata->clust_size = bs.cluster_size;
1051
1052         if (mydata->fatsize == 32) {
1053                 mydata->data_begin = mydata->rootdir_sect -
1054                                         (mydata->clust_size * 2);
1055         } else {
1056                 int rootdir_size;
1057
1058                 rootdir_size = ((bs.dir_entries[1]  * (int)256 +
1059                                  bs.dir_entries[0]) *
1060                                  sizeof(dir_entry)) /
1061                                  mydata->sect_size;
1062                 mydata->data_begin = mydata->rootdir_sect +
1063                                         rootdir_size -
1064                                         (mydata->clust_size * 2);
1065         }
1066
1067         mydata->fatbufnum = -1;
1068         mydata->fat_dirty = 0;
1069         mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
1070         if (mydata->fatbuf == NULL) {
1071                 debug("Error: allocating memory\n");
1072                 return -1;
1073         }
1074
1075         if (disk_read(cursect,
1076                 (mydata->fatsize == 32) ?
1077                 (mydata->clust_size) :
1078                 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
1079                 debug("Error: reading rootdir block\n");
1080                 goto exit;
1081         }
1082         dentptr = (dir_entry *) do_fat_read_at_block;
1083
1084         name_len = strlen(filename);
1085         if (name_len >= VFAT_MAXLEN_BYTES)
1086                 name_len = VFAT_MAXLEN_BYTES - 1;
1087
1088         memcpy(l_filename, filename, name_len);
1089         l_filename[name_len] = 0; /* terminate the string */
1090         downcase(l_filename);
1091
1092         startsect = mydata->rootdir_sect;
1093         retdent = find_directory_entry(mydata, startsect,
1094                                 l_filename, dentptr, 0);
1095         if (retdent) {
1096                 /* Update file size and start_cluster in a directory entry */
1097                 retdent->size = cpu_to_le32(size);
1098                 start_cluster = START(retdent);
1099
1100                 if (start_cluster) {
1101                         if (size) {
1102                                 ret = check_overflow(mydata, start_cluster,
1103                                                         size);
1104                                 if (ret) {
1105                                         printf("Error: %llu overflow\n", size);
1106                                         goto exit;
1107                                 }
1108                         }
1109
1110                         ret = clear_fatent(mydata, start_cluster);
1111                         if (ret) {
1112                                 printf("Error: clearing FAT entries\n");
1113                                 goto exit;
1114                         }
1115
1116                         if (!size)
1117                                 set_start_cluster(mydata, retdent, 0);
1118                 } else if (size) {
1119                         ret = start_cluster = find_empty_cluster(mydata);
1120                         if (ret < 0) {
1121                                 printf("Error: finding empty cluster\n");
1122                                 goto exit;
1123                         }
1124
1125                         ret = check_overflow(mydata, start_cluster, size);
1126                         if (ret) {
1127                                 printf("Error: %llu overflow\n", size);
1128                                 goto exit;
1129                         }
1130
1131                         set_start_cluster(mydata, retdent, start_cluster);
1132                 }
1133         } else {
1134                 /* Set short name to set alias checksum field in dir_slot */
1135                 set_name(empty_dentptr, filename);
1136                 fill_dir_slot(mydata, &empty_dentptr, filename);
1137
1138                 if (size) {
1139                         ret = start_cluster = find_empty_cluster(mydata);
1140                         if (ret < 0) {
1141                                 printf("Error: finding empty cluster\n");
1142                                 goto exit;
1143                         }
1144
1145                         ret = check_overflow(mydata, start_cluster, size);
1146                         if (ret) {
1147                                 printf("Error: %llu overflow\n", size);
1148                                 goto exit;
1149                         }
1150                 } else {
1151                         start_cluster = 0;
1152                 }
1153
1154                 /* Set attribute as archieve for regular file */
1155                 fill_dentry(mydata, empty_dentptr, filename,
1156                         start_cluster, size, 0x20);
1157
1158                 retdent = empty_dentptr;
1159         }
1160
1161         ret = set_contents(mydata, retdent, buffer, size, actwrite);
1162         if (ret < 0) {
1163                 printf("Error: writing contents\n");
1164                 goto exit;
1165         }
1166         debug("attempt to write 0x%llx bytes\n", *actwrite);
1167
1168         /* Flush fat buffer */
1169         ret = flush_dirty_fat_buffer(mydata);
1170         if (ret) {
1171                 printf("Error: flush fat buffer\n");
1172                 goto exit;
1173         }
1174
1175         /* Write directory table to device */
1176         ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
1177                         mydata->clust_size * mydata->sect_size);
1178         if (ret)
1179                 printf("Error: writing directory entry\n");
1180
1181 exit:
1182         free(mydata->fatbuf);
1183         return ret;
1184 }
1185
1186 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1187                    loff_t maxsize, loff_t *actwrite)
1188 {
1189         if (offset != 0) {
1190                 printf("Error: non zero offset is currently not supported.\n");
1191                 return -1;
1192         }
1193
1194         printf("writing %s\n", filename);
1195         return do_fat_write(filename, buffer, maxsize, actwrite);
1196 }