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         /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 121         if (startblock + getsize > fatlength)
 122                 getsize = fatlength - startblock;
 123
 124         startblock += mydata->fat_sect;
 125
 126         /* Write FAT buf */
 127         if (disk_write(startblock, getsize, bufptr) < 0) {
 128                 debug("error: writing FAT blocks\n");
 129                 return -1;
 130         }
 131
 132         if (num_of_fats == 2) {
 133                 /* Update corresponding second FAT blocks */
 134                 startblock += mydata->fatlength;
 135                 if (disk_write(startblock, getsize, bufptr) < 0) {
 136                         debug("error: writing second FAT blocks\n");
 137                         return -1;
 138                 }
 139         }
 140         mydata->fat_dirty = 0;
 141
 142         return 0;
 143 }
 144
 145 /*
 146  * Set the file name information from 'name' into 'slotptr',
 147  */
 148 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
 149 {
 150         int j, end_idx = 0;
 151
 152         for (j = 0; j <= 8; j += 2) {
 153                 if (name[*idx] == 0x00) {
 154                         slotptr->name0_4[j] = 0;
 155                         slotptr->name0_4[j + 1] = 0;
 156                         end_idx++;
 157                         goto name0_4;
 158                 }
 159                 slotptr->name0_4[j] = name[*idx];
 160                 (*idx)++;
 161                 end_idx++;
 162         }
 163         for (j = 0; j <= 10; j += 2) {
 164                 if (name[*idx] == 0x00) {
 165                         slotptr->name5_10[j] = 0;
 166                         slotptr->name5_10[j + 1] = 0;
 167                         end_idx++;
 168                         goto name5_10;
 169                 }
 170                 slotptr->name5_10[j] = name[*idx];
 171                 (*idx)++;
 172                 end_idx++;
 173         }
 174         for (j = 0; j <= 2; j += 2) {
 175                 if (name[*idx] == 0x00) {
 176                         slotptr->name11_12[j] = 0;
 177                         slotptr->name11_12[j + 1] = 0;
 178                         end_idx++;
 179                         goto name11_12;
 180                 }
 181                 slotptr->name11_12[j] = name[*idx];
 182                 (*idx)++;
 183                 end_idx++;
 184         }
 185
 186         if (name[*idx] == 0x00)
 187                 return 1;
 188
 189         return 0;
 190 /* Not used characters are filled with 0xff 0xff */
 191 name0_4:
 192         for (; end_idx < 5; end_idx++) {
 193                 slotptr->name0_4[end_idx * 2] = 0xff;
 194                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
 195         }
 196         end_idx = 5;
 197 name5_10:
 198         end_idx -= 5;
 199         for (; end_idx < 6; end_idx++) {
 200                 slotptr->name5_10[end_idx * 2] = 0xff;
 201                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
 202         }
 203         end_idx = 11;
 204 name11_12:
 205         end_idx -= 11;
 206         for (; end_idx < 2; end_idx++) {
 207                 slotptr->name11_12[end_idx * 2] = 0xff;
 208                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
 209         }
 210
 211         return 1;
 212 }
 213
 214 static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
 215 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
 216
 217 /*
 218  * Fill dir_slot entries with appropriate name, id, and attr
 219  * The real directory entry is returned by 'dentptr'
 220  */
 221 static void
 222 fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
 223 {
 224         __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
 225         dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
 226         __u8 counter = 0, checksum;
 227         int idx = 0, ret;
 228
 229         /* Get short file name checksum value */
 230         checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
 231
 232         do {
 233                 memset(slotptr, 0x00, sizeof(dir_slot));
 234                 ret = str2slot(slotptr, l_name, &idx);
 235                 slotptr->id = ++counter;
 236                 slotptr->attr = ATTR_VFAT;
 237                 slotptr->alias_checksum = checksum;
 238                 slotptr++;
 239         } while (ret == 0);
 240
 241         slotptr--;
 242         slotptr->id |= LAST_LONG_ENTRY_MASK;
 243
 244         while (counter >= 1) {
 245                 if (is_next_clust(mydata, *dentptr)) {
 246                         /* A new cluster is allocated for directory table */
 247                         flush_dir_table(mydata, dentptr);
 248                 }
 249                 memcpy(*dentptr, slotptr, sizeof(dir_slot));
 250                 (*dentptr)++;
 251                 slotptr--;
 252                 counter--;
 253         }
 254
 255         if (is_next_clust(mydata, *dentptr)) {
 256                 /* A new cluster is allocated for directory table */
 257                 flush_dir_table(mydata, dentptr);
 258         }
 259 }
 260
 261 static __u32 dir_curclust;
 262
 263 /*
 264  * Extract the full long filename starting at 'retdent' (which is really
 265  * a slot) into 'l_name'. If successful also copy the real directory entry
 266  * into 'retdent'
 267  * If additional adjacent cluster for directory entries is read into memory,
 268  * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
 269  * the location of the real directory entry is returned by 'retdent'
 270  * Return 0 on success, -1 otherwise.
 271  */
 272 static int
 273 get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
 274               dir_entry **retdent, char *l_name)
 275 {
 276         dir_entry *realdent;
 277         dir_slot *slotptr = (dir_slot *)(*retdent);
 278         dir_slot *slotptr2 = NULL;
 279         __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
 280                                                         PREFETCH_BLOCKS :
 281                                                         mydata->clust_size);
 282         __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
 283         int idx = 0, cur_position = 0;
 284
 285         if (counter > VFAT_MAXSEQ) {
 286                 debug("Error: VFAT name is too long\n");
 287                 return -1;
 288         }
 289
 290         while ((__u8 *)slotptr < buflimit) {
 291                 if (counter == 0)
 292                         break;
 293                 if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
 294                         return -1;
 295                 slotptr++;
 296                 counter--;
 297         }
 298
 299         if ((__u8 *)slotptr >= buflimit) {
 300                 if (curclust == 0)
 301                         return -1;
 302                 curclust = get_fatent(mydata, dir_curclust);
 303                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 304                         debug("curclust: 0x%x\n", curclust);
 305                         printf("Invalid FAT entry\n");
 306                         return -1;
 307                 }
 308
 309                 dir_curclust = curclust;
 310
 311                 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
 312                                 mydata->clust_size * mydata->sect_size) != 0) {
 313                         debug("Error: reading directory block\n");
 314                         return -1;
 315                 }
 316
 317                 slotptr2 = (dir_slot *)get_contents_vfatname_block;
 318                 while (counter > 0) {
 319                         if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
 320                             & 0xff) != counter)
 321                                 return -1;
 322                         slotptr2++;
 323                         counter--;
 324                 }
 325
 326                 /* Save the real directory entry */
 327                 realdent = (dir_entry *)slotptr2;
 328                 while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
 329                         slotptr2--;
 330                         slot2str(slotptr2, l_name, &idx);
 331                 }
 332         } else {
 333                 /* Save the real directory entry */
 334                 realdent = (dir_entry *)slotptr;
 335         }
 336
 337         do {
 338                 slotptr--;
 339                 if (slot2str(slotptr, l_name, &idx))
 340                         break;
 341         } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
 342
 343         l_name[idx] = '\0';
 344         if (*l_name == DELETED_FLAG)
 345                 *l_name = '\0';
 346         else if (*l_name == aRING)
 347                 *l_name = DELETED_FLAG;
 348         downcase(l_name, INT_MAX);
 349
 350         /* Return the real directory entry */
 351         *retdent = realdent;
 352
 353         if (slotptr2) {
 354                 memcpy(get_dentfromdir_block, get_contents_vfatname_block,
 355                         mydata->clust_size * mydata->sect_size);
 356                 cur_position = (__u8 *)realdent - get_contents_vfatname_block;
 357                 *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
 358         }
 359
 360         return 0;
 361 }
 362
 363 /*
 364  * Set the entry at index 'entry' in a FAT (12/16/32) table.
 365  */
 366 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
 367 {
 368         __u32 bufnum, offset, off16;
 369         __u16 val1, val2;
 370
 371         switch (mydata->fatsize) {
 372         case 32:
 373                 bufnum = entry / FAT32BUFSIZE;
 374                 offset = entry - bufnum * FAT32BUFSIZE;
 375                 break;
 376         case 16:
 377                 bufnum = entry / FAT16BUFSIZE;
 378                 offset = entry - bufnum * FAT16BUFSIZE;
 379                 break;
 380         case 12:
 381                 bufnum = entry / FAT12BUFSIZE;
 382                 offset = entry - bufnum * FAT12BUFSIZE;
 383                 break;
 384         default:
 385                 /* Unsupported FAT size */
 386                 return -1;
 387         }
 388
 389         /* Read a new block of FAT entries into the cache. */
 390         if (bufnum != mydata->fatbufnum) {
 391                 int getsize = FATBUFBLOCKS;
 392                 __u8 *bufptr = mydata->fatbuf;
 393                 __u32 fatlength = mydata->fatlength;
 394                 __u32 startblock = bufnum * FATBUFBLOCKS;
 395
 396                 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
 397                 if (startblock + getsize > fatlength)
 398                         getsize = fatlength - startblock;
 399
 400                 if (flush_dirty_fat_buffer(mydata) < 0)
 401                         return -1;
 402
 403                 startblock += mydata->fat_sect;
 404
 405                 if (disk_read(startblock, getsize, bufptr) < 0) {
 406                         debug("Error reading FAT blocks\n");
 407                         return -1;
 408                 }
 409                 mydata->fatbufnum = bufnum;
 410         }
 411
 412         /* Mark as dirty */
 413         mydata->fat_dirty = 1;
 414
 415         /* Set the actual entry */
 416         switch (mydata->fatsize) {
 417         case 32:
 418                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
 419                 break;
 420         case 16:
 421                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
 422                 break;
 423         case 12:
 424                 off16 = (offset * 3) / 4;
 425
 426                 switch (offset & 0x3) {
 427                 case 0:
 428                         val1 = cpu_to_le16(entry_value) & 0xfff;
 429                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
 430                         ((__u16 *)mydata->fatbuf)[off16] |= val1;
 431                         break;
 432                 case 1:
 433                         val1 = cpu_to_le16(entry_value) & 0xf;
 434                         val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
 435
 436                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
 437                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
 438
 439                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
 440                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 441                         break;
 442                 case 2:
 443                         val1 = cpu_to_le16(entry_value) & 0xff;
 444                         val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
 445
 446                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
 447                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
 448
 449                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
 450                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
 451                         break;
 452                 case 3:
 453                         val1 = cpu_to_le16(entry_value) & 0xfff;
 454                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
 455                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
 456                         break;
 457                 default:
 458                         break;
 459                 }
 460
 461                 break;
 462         default:
 463                 return -1;
 464         }
 465
 466         return 0;
 467 }
 468
 469 /*
 470  * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
 471  * and link it to 'entry'. EOC marker is not set on returned entry.
 472  */
 473 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
 474 {
 475         __u32 next_fat, next_entry = entry + 1;
 476
 477         while (1) {
 478                 next_fat = get_fatent(mydata, next_entry);
 479                 if (next_fat == 0) {
 480                         /* found free entry, link to entry */
 481                         set_fatent_value(mydata, entry, next_entry);
 482                         break;
 483                 }
 484                 next_entry++;
 485         }
 486         debug("FAT%d: entry: %08x, entry_value: %04x\n",
 487                mydata->fatsize, entry, next_entry);
 488
 489         return next_entry;
 490 }
 491
 492 /*
 493  * Write at most 'size' bytes from 'buffer' into the specified cluster.
 494  * Return 0 on success, -1 otherwise.
 495  */
 496 static int
 497 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 498              unsigned long size)
 499 {
 500         __u32 idx = 0;
 501         __u32 startsect;
 502         int ret;
 503
 504         if (clustnum > 0)
 505                 startsect = clust_to_sect(mydata, clustnum);
 506         else
 507                 startsect = mydata->rootdir_sect;
 508
 509         debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 510
 511         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 512                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 513
 514                 printf("FAT: Misaligned buffer address (%p)\n", buffer);
 515
 516                 while (size >= mydata->sect_size) {
 517                         memcpy(tmpbuf, buffer, mydata->sect_size);
 518                         ret = disk_write(startsect++, 1, tmpbuf);
 519                         if (ret != 1) {
 520                                 debug("Error writing data (got %d)\n", ret);
 521                                 return -1;
 522                         }
 523
 524                         buffer += mydata->sect_size;
 525                         size -= mydata->sect_size;
 526                 }
 527         } else if (size >= mydata->sect_size) {
 528                 idx = size / mydata->sect_size;
 529                 ret = disk_write(startsect, idx, buffer);
 530                 if (ret != idx) {
 531                         debug("Error writing data (got %d)\n", ret);
 532                         return -1;
 533                 }
 534
 535                 startsect += idx;
 536                 idx *= mydata->sect_size;
 537                 buffer += idx;
 538                 size -= idx;
 539         }
 540
 541         if (size) {
 542                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 543
 544                 memcpy(tmpbuf, buffer, size);
 545                 ret = disk_write(startsect, 1, tmpbuf);
 546                 if (ret != 1) {
 547                         debug("Error writing data (got %d)\n", ret);
 548                         return -1;
 549                 }
 550         }
 551
 552         return 0;
 553 }
 554
 555 /*
 556  * Find the first empty cluster
 557  */
 558 static int find_empty_cluster(fsdata *mydata)
 559 {
 560         __u32 fat_val, entry = 3;
 561
 562         while (1) {
 563                 fat_val = get_fatent(mydata, entry);
 564                 if (fat_val == 0)
 565                         break;
 566                 entry++;
 567         }
 568
 569         return entry;
 570 }
 571
 572 /*
 573  * Write directory entries in 'get_dentfromdir_block' to block device
 574  */
 575 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
 576 {
 577         int dir_newclust = 0;
 578
 579         if (set_cluster(mydata, dir_curclust,
 580                     get_dentfromdir_block,
 581                     mydata->clust_size * mydata->sect_size) != 0) {
 582                 printf("error: wrinting directory entry\n");
 583                 return;
 584         }
 585         dir_newclust = find_empty_cluster(mydata);
 586         set_fatent_value(mydata, dir_curclust, dir_newclust);
 587         if (mydata->fatsize == 32)
 588                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 589         else if (mydata->fatsize == 16)
 590                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 591         else if (mydata->fatsize == 12)
 592                 set_fatent_value(mydata, dir_newclust, 0xff8);
 593
 594         dir_curclust = dir_newclust;
 595
 596         if (flush_dirty_fat_buffer(mydata) < 0)
 597                 return;
 598
 599         memset(get_dentfromdir_block, 0x00,
 600                 mydata->clust_size * mydata->sect_size);
 601
 602         *dentptr = (dir_entry *) get_dentfromdir_block;
 603 }
 604
 605 /*
 606  * Set empty cluster from 'entry' to the end of a file
 607  */
 608 static int clear_fatent(fsdata *mydata, __u32 entry)
 609 {
 610         __u32 fat_val;
 611
 612         while (!CHECK_CLUST(entry, mydata->fatsize)) {
 613                 fat_val = get_fatent(mydata, entry);
 614                 if (fat_val != 0)
 615                         set_fatent_value(mydata, entry, 0);
 616                 else
 617                         break;
 618
 619                 entry = fat_val;
 620         }
 621
 622         /* Flush fat buffer */
 623         if (flush_dirty_fat_buffer(mydata) < 0)
 624                 return -1;
 625
 626         return 0;
 627 }
 628
 629 /*
 630  * Write at most 'maxsize' bytes from 'buffer' into
 631  * the file associated with 'dentptr'
 632  * Update the number of bytes written in *gotsize and return 0
 633  * or return -1 on fatal errors.
 634  */
 635 static int
 636 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
 637               loff_t maxsize, loff_t *gotsize)
 638 {
 639         loff_t filesize = FAT2CPU32(dentptr->size);
 640         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 641         __u32 curclust = START(dentptr);
 642         __u32 endclust = 0, newclust = 0;
 643         loff_t actsize;
 644
 645         *gotsize = 0;
 646         debug("Filesize: %llu bytes\n", filesize);
 647
 648         if (maxsize > 0 && filesize > maxsize)
 649                 filesize = maxsize;
 650
 651         debug("%llu bytes\n", filesize);
 652
 653         if (!curclust) {
 654                 if (filesize) {
 655                         debug("error: nonempty clusterless file!\n");
 656                         return -1;
 657                 }
 658                 return 0;
 659         }
 660
 661         actsize = bytesperclust;
 662         endclust = curclust;
 663         do {
 664                 /* search for consecutive clusters */
 665                 while (actsize < filesize) {
 666                         newclust = determine_fatent(mydata, endclust);
 667
 668                         if ((newclust - 1) != endclust)
 669                                 goto getit;
 670
 671                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 672                                 debug("newclust: 0x%x\n", newclust);
 673                                 debug("Invalid FAT entry\n");
 674                                 return 0;
 675                         }
 676                         endclust = newclust;
 677                         actsize += bytesperclust;
 678                 }
 679
 680                 /* set remaining bytes */
 681                 actsize = filesize;
 682                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 683                         debug("error: writing cluster\n");
 684                         return -1;
 685                 }
 686                 *gotsize += actsize;
 687
 688                 /* Mark end of file in FAT */
 689                 if (mydata->fatsize == 12)
 690                         newclust = 0xfff;
 691                 else if (mydata->fatsize == 16)
 692                         newclust = 0xffff;
 693                 else if (mydata->fatsize == 32)
 694                         newclust = 0xfffffff;
 695                 set_fatent_value(mydata, endclust, newclust);
 696
 697                 return 0;
 698 getit:
 699                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 700                         debug("error: writing cluster\n");
 701                         return -1;
 702                 }
 703                 *gotsize += actsize;
 704                 filesize -= actsize;
 705                 buffer += actsize;
 706
 707                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 708                         debug("newclust: 0x%x\n", newclust);
 709                         debug("Invalid FAT entry\n");
 710                         return 0;
 711                 }
 712                 actsize = bytesperclust;
 713                 curclust = endclust = newclust;
 714         } while (1);
 715 }
 716
 717 /*
 718  * Set start cluster in directory entry
 719  */
 720 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 721                                 __u32 start_cluster)
 722 {
 723         if (mydata->fatsize == 32)
 724                 dentptr->starthi =
 725                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 726         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 727 }
 728
 729 /*
 730  * Fill dir_entry
 731  */
 732 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 733         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 734 {
 735         set_start_cluster(mydata, dentptr, start_cluster);
 736         dentptr->size = cpu_to_le32(size);
 737
 738         dentptr->attr = attr;
 739
 740         set_name(dentptr, filename);
 741 }
 742
 743 /*
 744  * Check whether adding a file makes the file system to
 745  * exceed the size of the block device
 746  * Return -1 when overflow occurs, otherwise return 0
 747  */
 748 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 749 {
 750         __u32 startsect, sect_num, offset;
 751
 752         if (clustnum > 0) {
 753                 startsect = clust_to_sect(mydata, clustnum);
 754         } else {
 755                 startsect = mydata->rootdir_sect;
 756         }
 757
 758         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 759
 760         if (offset != 0)
 761                 sect_num++;
 762
 763         if (startsect + sect_num > total_sector)
 764                 return -1;
 765         return 0;
 766 }
 767
 768 /*
 769  * Check if adding several entries exceed one cluster boundary
 770  */
 771 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
 772 {
 773         int cur_position;
 774
 775         cur_position = (__u8 *)dentptr - get_dentfromdir_block;
 776
 777         if (cur_position >= mydata->clust_size * mydata->sect_size)
 778                 return 1;
 779         else
 780                 return 0;
 781 }
 782
 783 static dir_entry *empty_dentptr;
 784 /*
 785  * Find a directory entry based on filename or start cluster number
 786  * If the directory entry is not found,
 787  * the new position for writing a directory entry will be returned
 788  */
 789 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
 790         char *filename, dir_entry *retdent, __u32 start)
 791 {
 792         __u32 curclust = sect_to_clust(mydata, startsect);
 793
 794         debug("get_dentfromdir: %s\n", filename);
 795
 796         while (1) {
 797                 dir_entry *dentptr;
 798
 799                 int i;
 800
 801                 if (get_cluster(mydata, curclust, get_dentfromdir_block,
 802                             mydata->clust_size * mydata->sect_size) != 0) {
 803                         printf("Error: reading directory block\n");
 804                         return NULL;
 805                 }
 806
 807                 dentptr = (dir_entry *)get_dentfromdir_block;
 808
 809                 dir_curclust = curclust;
 810
 811                 for (i = 0; i < DIRENTSPERCLUST; i++) {
 812                         char s_name[14], l_name[VFAT_MAXLEN_BYTES];
 813
 814                         l_name[0] = '\0';
 815                         if (dentptr->name[0] == DELETED_FLAG) {
 816                                 dentptr++;
 817                                 if (is_next_clust(mydata, dentptr))
 818                                         break;
 819                                 continue;
 820                         }
 821                         if ((dentptr->attr & ATTR_VOLUME)) {
 822                                 if ((dentptr->attr & ATTR_VFAT) &&
 823                                     (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
 824                                         get_long_file_name(mydata, curclust,
 825                                                      get_dentfromdir_block,
 826                                                      &dentptr, l_name);
 827                                         debug("vfatname: |%s|\n", l_name);
 828                                 } else {
 829                                         /* Volume label or VFAT entry */
 830                                         dentptr++;
 831                                         if (is_next_clust(mydata, dentptr))
 832                                                 break;
 833                                         continue;
 834                                 }
 835                         }
 836                         if (dentptr->name[0] == 0) {
 837                                 debug("Dentname == NULL - %d\n", i);
 838                                 empty_dentptr = dentptr;
 839                                 return NULL;
 840                         }
 841
 842                         get_name(dentptr, s_name);
 843
 844                         if (strncasecmp(filename, s_name, sizeof(s_name)) &&
 845                             strncasecmp(filename, l_name, sizeof(l_name))) {
 846                                 debug("Mismatch: |%s|%s|\n",
 847                                         s_name, l_name);
 848                                 dentptr++;
 849                                 if (is_next_clust(mydata, dentptr))
 850                                         break;
 851                                 continue;
 852                         }
 853
 854                         memcpy(retdent, dentptr, sizeof(dir_entry));
 855
 856                         debug("DentName: %s", s_name);
 857                         debug(", start: 0x%x", START(dentptr));
 858                         debug(", size:  0x%x %s\n",
 859                               FAT2CPU32(dentptr->size),
 860                               (dentptr->attr & ATTR_DIR) ?
 861                               "(DIR)" : "");
 862
 863                         return dentptr;
 864                 }
 865
 866                 /*
 867                  * In FAT16/12, the root dir is locate before data area, shows
 868                  * in following:
 869                  * -------------------------------------------------------------
 870                  * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
 871                  * -------------------------------------------------------------
 872                  *
 873                  * As a result if curclust is in Root dir, it is a negative
 874                  * number or 0, 1.
 875                  *
 876                  */
 877                 if (mydata->fatsize != 32 && (int)curclust <= 1) {
 878                         /* Current clust is in root dir, set to next clust */
 879                         curclust++;
 880                         if ((int)curclust <= 1)
 881                                 continue;       /* continue to find */
 882
 883                         /* Reach the end of root dir */
 884                         empty_dentptr = dentptr;
 885                         return NULL;
 886                 }
 887
 888                 curclust = get_fatent(mydata, dir_curclust);
 889                 if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 890                         empty_dentptr = dentptr;
 891                         return NULL;
 892                 }
 893                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 894                         debug("curclust: 0x%x\n", curclust);
 895                         debug("Invalid FAT entry\n");
 896                         return NULL;
 897                 }
 898         }
 899
 900         return NULL;
 901 }
 902
 903 static int do_fat_write(const char *filename, void *buffer, loff_t size,
 904                         loff_t *actwrite)
 905 {
 906         dir_entry *dentptr, *retdent;
 907         __u32 startsect;
 908         __u32 start_cluster;
 909         boot_sector bs;
 910         volume_info volinfo;
 911         fsdata datablock;
 912         fsdata *mydata = &datablock;
 913         int cursect;
 914         int ret = -1, name_len;
 915         char l_filename[VFAT_MAXLEN_BYTES];
 916
 917         *actwrite = size;
 918         dir_curclust = 0;
 919
 920         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 921                 debug("error: reading boot sector\n");
 922                 return -1;
 923         }
 924
 925         total_sector = bs.total_sect;
 926         if (total_sector == 0)
 927                 total_sector = (int)cur_part_info.size; /* cast of lbaint_t */
 928
 929         if (mydata->fatsize == 32)
 930                 mydata->fatlength = bs.fat32_length;
 931         else
 932                 mydata->fatlength = bs.fat_length;
 933
 934         mydata->fat_sect = bs.reserved;
 935
 936         cursect = mydata->rootdir_sect
 937                 = mydata->fat_sect + mydata->fatlength * bs.fats;
 938         num_of_fats = bs.fats;
 939
 940         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
 941         mydata->clust_size = bs.cluster_size;
 942
 943         if (mydata->fatsize == 32) {
 944                 mydata->data_begin = mydata->rootdir_sect -
 945                                         (mydata->clust_size * 2);
 946         } else {
 947                 int rootdir_size;
 948
 949                 rootdir_size = ((bs.dir_entries[1]  * (int)256 +
 950                                  bs.dir_entries[0]) *
 951                                  sizeof(dir_entry)) /
 952                                  mydata->sect_size;
 953                 mydata->data_begin = mydata->rootdir_sect +
 954                                         rootdir_size -
 955                                         (mydata->clust_size * 2);
 956         }
 957
 958         mydata->fatbufnum = -1;
 959         mydata->fat_dirty = 0;
 960         mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
 961         if (mydata->fatbuf == NULL) {
 962                 debug("Error: allocating memory\n");
 963                 return -1;
 964         }
 965
 966         if (disk_read(cursect,
 967                 (mydata->fatsize == 32) ?
 968                 (mydata->clust_size) :
 969                 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
 970                 debug("Error: reading rootdir block\n");
 971                 goto exit;
 972         }
 973         dentptr = (dir_entry *) do_fat_read_at_block;
 974
 975         name_len = strlen(filename);
 976         if (name_len >= VFAT_MAXLEN_BYTES)
 977                 name_len = VFAT_MAXLEN_BYTES - 1;
 978
 979         memcpy(l_filename, filename, name_len);
 980         l_filename[name_len] = 0; /* terminate the string */
 981         downcase(l_filename, INT_MAX);
 982
 983         startsect = mydata->rootdir_sect;
 984         retdent = find_directory_entry(mydata, startsect,
 985                                 l_filename, dentptr, 0);
 986         if (retdent) {
 987                 /* Update file size and start_cluster in a directory entry */
 988                 retdent->size = cpu_to_le32(size);
 989                 start_cluster = START(retdent);
 990
 991                 if (start_cluster) {
 992                         if (size) {
 993                                 ret = check_overflow(mydata, start_cluster,
 994                                                         size);
 995                                 if (ret) {
 996                                         printf("Error: %llu overflow\n", size);
 997                                         goto exit;
 998                                 }
 999                         }
1000
1001                         ret = clear_fatent(mydata, start_cluster);
1002                         if (ret) {
1003                                 printf("Error: clearing FAT entries\n");
1004                                 goto exit;
1005                         }
1006
1007                         if (!size)
1008                                 set_start_cluster(mydata, retdent, 0);
1009                 } else if (size) {
1010                         ret = start_cluster = find_empty_cluster(mydata);
1011                         if (ret < 0) {
1012                                 printf("Error: finding empty cluster\n");
1013                                 goto exit;
1014                         }
1015
1016                         ret = check_overflow(mydata, start_cluster, size);
1017                         if (ret) {
1018                                 printf("Error: %llu overflow\n", size);
1019                                 goto exit;
1020                         }
1021
1022                         set_start_cluster(mydata, retdent, start_cluster);
1023                 }
1024         } else {
1025                 /* Set short name to set alias checksum field in dir_slot */
1026                 set_name(empty_dentptr, filename);
1027                 fill_dir_slot(mydata, &empty_dentptr, filename);
1028
1029                 if (size) {
1030                         ret = start_cluster = find_empty_cluster(mydata);
1031                         if (ret < 0) {
1032                                 printf("Error: finding empty cluster\n");
1033                                 goto exit;
1034                         }
1035
1036                         ret = check_overflow(mydata, start_cluster, size);
1037                         if (ret) {
1038                                 printf("Error: %llu overflow\n", size);
1039                                 goto exit;
1040                         }
1041                 } else {
1042                         start_cluster = 0;
1043                 }
1044
1045                 /* Set attribute as archieve for regular file */
1046                 fill_dentry(mydata, empty_dentptr, filename,
1047                         start_cluster, size, 0x20);
1048
1049                 retdent = empty_dentptr;
1050         }
1051
1052         ret = set_contents(mydata, retdent, buffer, size, actwrite);
1053         if (ret < 0) {
1054                 printf("Error: writing contents\n");
1055                 goto exit;
1056         }
1057         debug("attempt to write 0x%llx bytes\n", *actwrite);
1058
1059         /* Flush fat buffer */
1060         ret = flush_dirty_fat_buffer(mydata);
1061         if (ret) {
1062                 printf("Error: flush fat buffer\n");
1063                 goto exit;
1064         }
1065
1066         /* Write directory table to device */
1067         ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
1068                         mydata->clust_size * mydata->sect_size);
1069         if (ret)
1070                 printf("Error: writing directory entry\n");
1071
1072 exit:
1073         free(mydata->fatbuf);
1074         return ret;
1075 }
1076
1077 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1078                    loff_t maxsize, loff_t *actwrite)
1079 {
1080         if (offset != 0) {
1081                 printf("Error: non zero offset is currently not supported.\n");
1082                 return -1;
1083         }
1084
1085         printf("writing %s\n", filename);
1086         return do_fat_write(filename, buffer, maxsize, actwrite);
1087 }