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  * 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 = mydata->data_begin +
 506                                 clustnum * mydata->clust_size;
 507         else
 508                 startsect = mydata->rootdir_sect;
 509
 510         debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 511
 512         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
 513                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 514
 515                 printf("FAT: Misaligned buffer address (%p)\n", buffer);
 516
 517                 while (size >= mydata->sect_size) {
 518                         memcpy(tmpbuf, buffer, mydata->sect_size);
 519                         ret = disk_write(startsect++, 1, tmpbuf);
 520                         if (ret != 1) {
 521                                 debug("Error writing data (got %d)\n", ret);
 522                                 return -1;
 523                         }
 524
 525                         buffer += mydata->sect_size;
 526                         size -= mydata->sect_size;
 527                 }
 528         } else if (size >= mydata->sect_size) {
 529                 idx = size / mydata->sect_size;
 530                 ret = disk_write(startsect, idx, buffer);
 531                 if (ret != idx) {
 532                         debug("Error writing data (got %d)\n", ret);
 533                         return -1;
 534                 }
 535
 536                 startsect += idx;
 537                 idx *= mydata->sect_size;
 538                 buffer += idx;
 539                 size -= idx;
 540         }
 541
 542         if (size) {
 543                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
 544
 545                 memcpy(tmpbuf, buffer, size);
 546                 ret = disk_write(startsect, 1, tmpbuf);
 547                 if (ret != 1) {
 548                         debug("Error writing data (got %d)\n", ret);
 549                         return -1;
 550                 }
 551         }
 552
 553         return 0;
 554 }
 555
 556 /*
 557  * Find the first empty cluster
 558  */
 559 static int find_empty_cluster(fsdata *mydata)
 560 {
 561         __u32 fat_val, entry = 3;
 562
 563         while (1) {
 564                 fat_val = get_fatent(mydata, entry);
 565                 if (fat_val == 0)
 566                         break;
 567                 entry++;
 568         }
 569
 570         return entry;
 571 }
 572
 573 /*
 574  * Write directory entries in 'get_dentfromdir_block' to block device
 575  */
 576 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
 577 {
 578         int dir_newclust = 0;
 579
 580         if (set_cluster(mydata, dir_curclust,
 581                     get_dentfromdir_block,
 582                     mydata->clust_size * mydata->sect_size) != 0) {
 583                 printf("error: wrinting directory entry\n");
 584                 return;
 585         }
 586         dir_newclust = find_empty_cluster(mydata);
 587         set_fatent_value(mydata, dir_curclust, dir_newclust);
 588         if (mydata->fatsize == 32)
 589                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
 590         else if (mydata->fatsize == 16)
 591                 set_fatent_value(mydata, dir_newclust, 0xfff8);
 592         else if (mydata->fatsize == 12)
 593                 set_fatent_value(mydata, dir_newclust, 0xff8);
 594
 595         dir_curclust = dir_newclust;
 596
 597         if (flush_dirty_fat_buffer(mydata) < 0)
 598                 return;
 599
 600         memset(get_dentfromdir_block, 0x00,
 601                 mydata->clust_size * mydata->sect_size);
 602
 603         *dentptr = (dir_entry *) get_dentfromdir_block;
 604 }
 605
 606 /*
 607  * Set empty cluster from 'entry' to the end of a file
 608  */
 609 static int clear_fatent(fsdata *mydata, __u32 entry)
 610 {
 611         __u32 fat_val;
 612
 613         while (!CHECK_CLUST(entry, mydata->fatsize)) {
 614                 fat_val = get_fatent(mydata, entry);
 615                 if (fat_val != 0)
 616                         set_fatent_value(mydata, entry, 0);
 617                 else
 618                         break;
 619
 620                 entry = fat_val;
 621         }
 622
 623         /* Flush fat buffer */
 624         if (flush_dirty_fat_buffer(mydata) < 0)
 625                 return -1;
 626
 627         return 0;
 628 }
 629
 630 /*
 631  * Write at most 'maxsize' bytes from 'buffer' into
 632  * the file associated with 'dentptr'
 633  * Update the number of bytes written in *gotsize and return 0
 634  * or return -1 on fatal errors.
 635  */
 636 static int
 637 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
 638               loff_t maxsize, loff_t *gotsize)
 639 {
 640         loff_t filesize = FAT2CPU32(dentptr->size);
 641         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 642         __u32 curclust = START(dentptr);
 643         __u32 endclust = 0, newclust = 0;
 644         loff_t actsize;
 645
 646         *gotsize = 0;
 647         debug("Filesize: %llu bytes\n", filesize);
 648
 649         if (maxsize > 0 && filesize > maxsize)
 650                 filesize = maxsize;
 651
 652         debug("%llu bytes\n", filesize);
 653
 654         if (!curclust) {
 655                 if (filesize) {
 656                         debug("error: nonempty clusterless file!\n");
 657                         return -1;
 658                 }
 659                 return 0;
 660         }
 661
 662         actsize = bytesperclust;
 663         endclust = curclust;
 664         do {
 665                 /* search for consecutive clusters */
 666                 while (actsize < filesize) {
 667                         newclust = determine_fatent(mydata, endclust);
 668
 669                         if ((newclust - 1) != endclust)
 670                                 goto getit;
 671
 672                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
 673                                 debug("newclust: 0x%x\n", newclust);
 674                                 debug("Invalid FAT entry\n");
 675                                 return 0;
 676                         }
 677                         endclust = newclust;
 678                         actsize += bytesperclust;
 679                 }
 680
 681                 /* set remaining bytes */
 682                 actsize = filesize;
 683                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 684                         debug("error: writing cluster\n");
 685                         return -1;
 686                 }
 687                 *gotsize += actsize;
 688
 689                 /* Mark end of file in FAT */
 690                 if (mydata->fatsize == 12)
 691                         newclust = 0xfff;
 692                 else if (mydata->fatsize == 16)
 693                         newclust = 0xffff;
 694                 else if (mydata->fatsize == 32)
 695                         newclust = 0xfffffff;
 696                 set_fatent_value(mydata, endclust, newclust);
 697
 698                 return 0;
 699 getit:
 700                 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
 701                         debug("error: writing cluster\n");
 702                         return -1;
 703                 }
 704                 *gotsize += actsize;
 705                 filesize -= actsize;
 706                 buffer += actsize;
 707
 708                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
 709                         debug("newclust: 0x%x\n", newclust);
 710                         debug("Invalid FAT entry\n");
 711                         return 0;
 712                 }
 713                 actsize = bytesperclust;
 714                 curclust = endclust = newclust;
 715         } while (1);
 716 }
 717
 718 /*
 719  * Set start cluster in directory entry
 720  */
 721 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
 722                                 __u32 start_cluster)
 723 {
 724         if (mydata->fatsize == 32)
 725                 dentptr->starthi =
 726                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
 727         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
 728 }
 729
 730 /*
 731  * Fill dir_entry
 732  */
 733 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
 734         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
 735 {
 736         set_start_cluster(mydata, dentptr, start_cluster);
 737         dentptr->size = cpu_to_le32(size);
 738
 739         dentptr->attr = attr;
 740
 741         set_name(dentptr, filename);
 742 }
 743
 744 /*
 745  * Check whether adding a file makes the file system to
 746  * exceed the size of the block device
 747  * Return -1 when overflow occurs, otherwise return 0
 748  */
 749 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
 750 {
 751         __u32 startsect, sect_num, offset;
 752
 753         if (clustnum > 0) {
 754                 startsect = mydata->data_begin +
 755                                 clustnum * mydata->clust_size;
 756         } else {
 757                 startsect = mydata->rootdir_sect;
 758         }
 759
 760         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
 761
 762         if (offset != 0)
 763                 sect_num++;
 764
 765         if (startsect + sect_num > total_sector)
 766                 return -1;
 767         return 0;
 768 }
 769
 770 /*
 771  * Check if adding several entries exceed one cluster boundary
 772  */
 773 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
 774 {
 775         int cur_position;
 776
 777         cur_position = (__u8 *)dentptr - get_dentfromdir_block;
 778
 779         if (cur_position >= mydata->clust_size * mydata->sect_size)
 780                 return 1;
 781         else
 782                 return 0;
 783 }
 784
 785 static dir_entry *empty_dentptr;
 786 /*
 787  * Find a directory entry based on filename or start cluster number
 788  * If the directory entry is not found,
 789  * the new position for writing a directory entry will be returned
 790  */
 791 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
 792         char *filename, dir_entry *retdent, __u32 start)
 793 {
 794         __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
 795
 796         debug("get_dentfromdir: %s\n", filename);
 797
 798         while (1) {
 799                 dir_entry *dentptr;
 800
 801                 int i;
 802
 803                 if (get_cluster(mydata, curclust, get_dentfromdir_block,
 804                             mydata->clust_size * mydata->sect_size) != 0) {
 805                         printf("Error: reading directory block\n");
 806                         return NULL;
 807                 }
 808
 809                 dentptr = (dir_entry *)get_dentfromdir_block;
 810
 811                 dir_curclust = curclust;
 812
 813                 for (i = 0; i < DIRENTSPERCLUST; i++) {
 814                         char s_name[14], l_name[VFAT_MAXLEN_BYTES];
 815
 816                         l_name[0] = '\0';
 817                         if (dentptr->name[0] == DELETED_FLAG) {
 818                                 dentptr++;
 819                                 if (is_next_clust(mydata, dentptr))
 820                                         break;
 821                                 continue;
 822                         }
 823                         if ((dentptr->attr & ATTR_VOLUME)) {
 824                                 if (vfat_enabled &&
 825                                     (dentptr->attr & ATTR_VFAT) &&
 826                                     (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
 827                                         get_long_file_name(mydata, curclust,
 828                                                      get_dentfromdir_block,
 829                                                      &dentptr, l_name);
 830                                         debug("vfatname: |%s|\n", l_name);
 831                                 } else {
 832                                         /* Volume label or VFAT entry */
 833                                         dentptr++;
 834                                         if (is_next_clust(mydata, dentptr))
 835                                                 break;
 836                                         continue;
 837                                 }
 838                         }
 839                         if (dentptr->name[0] == 0) {
 840                                 debug("Dentname == NULL - %d\n", i);
 841                                 empty_dentptr = dentptr;
 842                                 return NULL;
 843                         }
 844
 845                         get_name(dentptr, s_name);
 846
 847                         if (strcmp(filename, s_name)
 848                             && strcmp(filename, l_name)) {
 849                                 debug("Mismatch: |%s|%s|\n",
 850                                         s_name, l_name);
 851                                 dentptr++;
 852                                 if (is_next_clust(mydata, dentptr))
 853                                         break;
 854                                 continue;
 855                         }
 856
 857                         memcpy(retdent, dentptr, sizeof(dir_entry));
 858
 859                         debug("DentName: %s", s_name);
 860                         debug(", start: 0x%x", START(dentptr));
 861                         debug(", size:  0x%x %s\n",
 862                               FAT2CPU32(dentptr->size),
 863                               (dentptr->attr & ATTR_DIR) ?
 864                               "(DIR)" : "");
 865
 866                         return dentptr;
 867                 }
 868
 869                 /*
 870                  * In FAT16/12, the root dir is locate before data area, shows
 871                  * in following:
 872                  * -------------------------------------------------------------
 873                  * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
 874                  * -------------------------------------------------------------
 875                  *
 876                  * As a result if curclust is in Root dir, it is a negative
 877                  * number or 0, 1.
 878                  *
 879                  */
 880                 if (mydata->fatsize != 32 && (int)curclust <= 1) {
 881                         /* Current clust is in root dir, set to next clust */
 882                         curclust++;
 883                         if ((int)curclust <= 1)
 884                                 continue;       /* continue to find */
 885
 886                         /* Reach the end of root dir */
 887                         empty_dentptr = dentptr;
 888                         return NULL;
 889                 }
 890
 891                 curclust = get_fatent(mydata, dir_curclust);
 892                 if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
 893                         empty_dentptr = dentptr;
 894                         return NULL;
 895                 }
 896                 if (CHECK_CLUST(curclust, mydata->fatsize)) {
 897                         debug("curclust: 0x%x\n", curclust);
 898                         debug("Invalid FAT entry\n");
 899                         return NULL;
 900                 }
 901         }
 902
 903         return NULL;
 904 }
 905
 906 static int do_fat_write(const char *filename, void *buffer, loff_t size,
 907                         loff_t *actwrite)
 908 {
 909         dir_entry *dentptr, *retdent;
 910         __u32 startsect;
 911         __u32 start_cluster;
 912         boot_sector bs;
 913         volume_info volinfo;
 914         fsdata datablock;
 915         fsdata *mydata = &datablock;
 916         int cursect;
 917         int ret = -1, name_len;
 918         char l_filename[VFAT_MAXLEN_BYTES];
 919
 920         *actwrite = size;
 921         dir_curclust = 0;
 922
 923         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 924                 debug("error: reading boot sector\n");
 925                 return -1;
 926         }
 927
 928         total_sector = bs.total_sect;
 929         if (total_sector == 0)
 930                 total_sector = (int)cur_part_info.size; /* cast of lbaint_t */
 931
 932         if (mydata->fatsize == 32)
 933                 mydata->fatlength = bs.fat32_length;
 934         else
 935                 mydata->fatlength = bs.fat_length;
 936
 937         mydata->fat_sect = bs.reserved;
 938
 939         cursect = mydata->rootdir_sect
 940                 = mydata->fat_sect + mydata->fatlength * bs.fats;
 941         num_of_fats = bs.fats;
 942
 943         mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
 944         mydata->clust_size = bs.cluster_size;
 945
 946         if (mydata->fatsize == 32) {
 947                 mydata->data_begin = mydata->rootdir_sect -
 948                                         (mydata->clust_size * 2);
 949         } else {
 950                 int rootdir_size;
 951
 952                 rootdir_size = ((bs.dir_entries[1]  * (int)256 +
 953                                  bs.dir_entries[0]) *
 954                                  sizeof(dir_entry)) /
 955                                  mydata->sect_size;
 956                 mydata->data_begin = mydata->rootdir_sect +
 957                                         rootdir_size -
 958                                         (mydata->clust_size * 2);
 959         }
 960
 961         mydata->fatbufnum = -1;
 962         mydata->fat_dirty = 0;
 963         mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
 964         if (mydata->fatbuf == NULL) {
 965                 debug("Error: allocating memory\n");
 966                 return -1;
 967         }
 968
 969         if (disk_read(cursect,
 970                 (mydata->fatsize == 32) ?
 971                 (mydata->clust_size) :
 972                 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
 973                 debug("Error: reading rootdir block\n");
 974                 goto exit;
 975         }
 976         dentptr = (dir_entry *) do_fat_read_at_block;
 977
 978         name_len = strlen(filename);
 979         if (name_len >= VFAT_MAXLEN_BYTES)
 980                 name_len = VFAT_MAXLEN_BYTES - 1;
 981
 982         memcpy(l_filename, filename, name_len);
 983         l_filename[name_len] = 0; /* terminate the string */
 984         downcase(l_filename, INT_MAX);
 985
 986         startsect = mydata->rootdir_sect;
 987         retdent = find_directory_entry(mydata, startsect,
 988                                 l_filename, dentptr, 0);
 989         if (retdent) {
 990                 /* Update file size and start_cluster in a directory entry */
 991                 retdent->size = cpu_to_le32(size);
 992                 start_cluster = START(retdent);
 993
 994                 if (start_cluster) {
 995                         if (size) {
 996                                 ret = check_overflow(mydata, start_cluster,
 997                                                         size);
 998                                 if (ret) {
 999                                         printf("Error: %llu overflow\n", size);
1000                                         goto exit;
1001                                 }
1002                         }
1003
1004                         ret = clear_fatent(mydata, start_cluster);
1005                         if (ret) {
1006                                 printf("Error: clearing FAT entries\n");
1007                                 goto exit;
1008                         }
1009
1010                         if (!size)
1011                                 set_start_cluster(mydata, retdent, 0);
1012                 } else if (size) {
1013                         ret = start_cluster = find_empty_cluster(mydata);
1014                         if (ret < 0) {
1015                                 printf("Error: finding empty cluster\n");
1016                                 goto exit;
1017                         }
1018
1019                         ret = check_overflow(mydata, start_cluster, size);
1020                         if (ret) {
1021                                 printf("Error: %llu overflow\n", size);
1022                                 goto exit;
1023                         }
1024
1025                         set_start_cluster(mydata, retdent, start_cluster);
1026                 }
1027         } else {
1028                 /* Set short name to set alias checksum field in dir_slot */
1029                 set_name(empty_dentptr, filename);
1030                 fill_dir_slot(mydata, &empty_dentptr, filename);
1031
1032                 if (size) {
1033                         ret = start_cluster = find_empty_cluster(mydata);
1034                         if (ret < 0) {
1035                                 printf("Error: finding empty cluster\n");
1036                                 goto exit;
1037                         }
1038
1039                         ret = check_overflow(mydata, start_cluster, size);
1040                         if (ret) {
1041                                 printf("Error: %llu overflow\n", size);
1042                                 goto exit;
1043                         }
1044                 } else {
1045                         start_cluster = 0;
1046                 }
1047
1048                 /* Set attribute as archieve for regular file */
1049                 fill_dentry(mydata, empty_dentptr, filename,
1050                         start_cluster, size, 0x20);
1051
1052                 retdent = empty_dentptr;
1053         }
1054
1055         ret = set_contents(mydata, retdent, buffer, size, actwrite);
1056         if (ret < 0) {
1057                 printf("Error: writing contents\n");
1058                 goto exit;
1059         }
1060         debug("attempt to write 0x%llx bytes\n", *actwrite);
1061
1062         /* Flush fat buffer */
1063         ret = flush_dirty_fat_buffer(mydata);
1064         if (ret) {
1065                 printf("Error: flush fat buffer\n");
1066                 goto exit;
1067         }
1068
1069         /* Write directory table to device */
1070         ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
1071                         mydata->clust_size * mydata->sect_size);
1072         if (ret)
1073                 printf("Error: writing directory entry\n");
1074
1075 exit:
1076         free(mydata->fatbuf);
1077         return ret;
1078 }
1079
1080 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1081                    loff_t maxsize, loff_t *actwrite)
1082 {
1083         if (offset != 0) {
1084                 printf("Error: non zero offset is currently not supported.\n");
1085                 return -1;
1086         }
1087
1088         printf("writing %s\n", filename);
1089         return do_fat_write(filename, buffer, maxsize, actwrite);
1090 }