LXR busybox/util-linux/mkfs

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * mkfs_vfat: utility to create FAT32 filesystem
   4 * inspired by dosfstools
   5 *
   6 * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
   7 *
   8 * Licensed under GPLv2, see file LICENSE in this tarball for details.
   9 */
  10#include "libbb.h"
  11
  12#include <linux/hdreg.h> /* HDIO_GETGEO */
  13#include <linux/fd.h>    /* FDGETPRM */
  14#include <sys/mount.h>   /* BLKSSZGET */
  15#if !defined(BLKSSZGET)
  16# define BLKSSZGET _IO(0x12, 104)
  17#endif
  18//#include <linux/msdos_fs.h>
  19
  20#define SECTOR_SIZE             512
  21
  22#define SECTORS_PER_BLOCK       (BLOCK_SIZE / SECTOR_SIZE)
  23
  24// M$ says the high 4 bits of a FAT32 FAT entry are reserved
  25#define EOF_FAT32       0x0FFFFFF8
  26#define BAD_FAT32       0x0FFFFFF7
  27#define MAX_CLUST_32    0x0FFFFFF0
  28
  29#define ATTR_VOLUME     8
  30
  31#define NUM_FATS        2
  32
  33/* FAT32 filesystem looks like this:
  34 * sector -nn...-1: "hidden" sectors, all sectors before this partition
  35 * (-h hidden-sectors sets it. Useful only for boot loaders,
  36 *  they need to know _disk_ offset in order to be able to correctly
  37 *  address sectors relative to start of disk)
  38 * sector 0: boot sector
  39 * sector 1: info sector
  40 * sector 2: set aside for boot code which didn't fit into sector 0
  41 * ...(zero-filled sectors)...
  42 * sector B: backup copy of sector 0 [B set by -b backup-boot-sector]
  43 * sector B+1: backup copy of sector 1
  44 * sector B+2: backup copy of sector 2
  45 * ...(zero-filled sectors)...
  46 * sector R: FAT#1 [R set by -R reserved-sectors]
  47 * ...(FAT#1)...
  48 * sector R+fat_size: FAT#2
  49 * ...(FAT#2)...
  50 * sector R+fat_size*2: cluster #2
  51 * ...(cluster #2)...
  52 * sector R+fat_size*2+clust_size: cluster #3
  53 * ...(the rest is filled by clusters till the end)...
  54 */
  55
  56enum {
  57// Perhaps this should remain constant
  58        info_sector_number = 1,
  59// TODO: make these cmdline options
  60// dont forget sanity check: backup_boot_sector + 3 <= reserved_sect
  61        backup_boot_sector = 3,
  62        reserved_sect      = 6,
  63};
  64
  65// how many blocks we try to read while testing
  66#define TEST_BUFFER_BLOCKS      16
  67
  68struct msdos_dir_entry {
  69        char     name[11];       /* 000 name and extension */
  70        uint8_t  attr;           /* 00b attribute bits */
  71        uint8_t  lcase;          /* 00c case for base and extension */
  72        uint8_t  ctime_cs;       /* 00d creation time, centiseconds (0-199) */
  73        uint16_t ctime;          /* 00e creation time */
  74        uint16_t cdate;          /* 010 creation date */
  75        uint16_t adate;          /* 012 last access date */
  76        uint16_t starthi;        /* 014 high 16 bits of cluster in FAT32 */
  77        uint16_t time;           /* 016 time */
  78        uint16_t date;           /* 018 date */
  79        uint16_t start;          /* 01a first cluster */
  80        uint32_t size;           /* 01c file size in bytes */
  81} PACKED;
  82
  83/* Example of boot sector's beginning:
  840000  eb 58 90 4d 53 57 49 4e  34 2e 31 00 02 08 26 00  |...MSWIN4.1...&.|
  850010  02 00 00 00 00 f8 00 00  3f 00 ff 00 3f 00 00 00  |........?...?...|
  860020  54 9b d0 00 0d 34 00 00  00 00 00 00 02 00 00 00  |T....4..........|
  870030  01 00 06 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
  880040  80 00 29 71 df 51 e0 4e  4f 20 4e 41 4d 45 20 20  |..)q.Q.NO NAME  |
  890050  20 20 46 41 54 33 32 20  20 20 33 c9 8e d1 bc f4  |  FAT32   3.....|
  90*/
  91struct msdos_volume_info { /* (offsets are relative to start of boot sector) */
  92        uint8_t  drive_number;    /* 040 BIOS drive number */
  93        uint8_t  reserved;        /* 041 unused */
  94        uint8_t  ext_boot_sign;   /* 042 0x29 if fields below exist (DOS 3.3+) */
  95        uint32_t volume_id32;     /* 043 volume ID number */
  96        char     volume_label[11];/* 047 volume label */
  97        char     fs_type[8];      /* 052 typically "FATnn" */
  98} PACKED;                         /* 05a end. Total size 26 (0x1a) bytes */
  99
 100struct msdos_boot_sector {
 101        /* We use strcpy to fill both, and gcc-4.4.x complains if they are separate */
 102        char     boot_jump_and_sys_id[3+8]; /* 000 short or near jump instruction */
 103        /*char   system_id[8];*/     /* 003 name - can be used to special case partition manager volumes */
 104        uint16_t bytes_per_sect;     /* 00b bytes per logical sector */
 105        uint8_t  sect_per_clust;     /* 00d sectors/cluster */
 106        uint16_t reserved_sect;      /* 00e reserved sectors (sector offset of 1st FAT relative to volume start) */
 107        uint8_t  fats;               /* 010 number of FATs */
 108        uint16_t dir_entries;        /* 011 root directory entries */
 109        uint16_t volume_size_sect;   /* 013 volume size in sectors */
 110        uint8_t  media_byte;         /* 015 media code */
 111        uint16_t sect_per_fat;       /* 016 sectors/FAT */
 112        uint16_t sect_per_track;     /* 018 sectors per track */
 113        uint16_t heads;              /* 01a number of heads */
 114        uint32_t hidden;             /* 01c hidden sectors (sector offset of volume within physical disk) */
 115        uint32_t fat32_volume_size_sect; /* 020 volume size in sectors (if volume_size_sect == 0) */
 116        uint32_t fat32_sect_per_fat; /* 024 sectors/FAT */
 117        uint16_t fat32_flags;        /* 028 bit 8: fat mirroring, low 4: active fat */
 118        uint8_t  fat32_version[2];   /* 02a major, minor filesystem version (I see 0,0) */
 119        uint32_t fat32_root_cluster; /* 02c first cluster in root directory */
 120        uint16_t fat32_info_sector;  /* 030 filesystem info sector (usually 1) */
 121        uint16_t fat32_backup_boot;  /* 032 backup boot sector (usually 6) */
 122        uint32_t reserved2[3];       /* 034 unused */
 123        struct msdos_volume_info vi; /* 040 */
 124        char     boot_code[0x200 - 0x5a - 2]; /* 05a */
 125#define BOOT_SIGN 0xAA55
 126        uint16_t boot_sign;          /* 1fe */
 127} PACKED;
 128
 129#define FAT_FSINFO_SIG1 0x41615252
 130#define FAT_FSINFO_SIG2 0x61417272
 131struct fat32_fsinfo {
 132        uint32_t signature1;         /* 0x52,0x52,0x41,0x61, "RRaA" */
 133        uint32_t reserved1[128 - 8];
 134        uint32_t signature2;         /* 0x72,0x72,0x61,0x41, "rrAa" */
 135        uint32_t free_clusters;      /* free cluster count.  -1 if unknown */
 136        uint32_t next_cluster;       /* most recently allocated cluster */
 137        uint32_t reserved2[3];
 138        uint16_t reserved3;          /* 1fc */
 139        uint16_t boot_sign;          /* 1fe */
 140} PACKED;
 141
 142struct bug_check {
 143        char BUG1[sizeof(struct msdos_dir_entry  ) == 0x20 ? 1 : -1];
 144        char BUG2[sizeof(struct msdos_volume_info) == 0x1a ? 1 : -1];
 145        char BUG3[sizeof(struct msdos_boot_sector) == 0x200 ? 1 : -1];
 146        char BUG4[sizeof(struct fat32_fsinfo     ) == 0x200 ? 1 : -1];
 147};
 148
 149static const char boot_code[] ALIGN1 =
 150        "\x0e"          /* 05a:         push  cs */
 151        "\x1f"          /* 05b:         pop   ds */
 152        "\xbe\x77\x7c"  /*  write_msg:  mov   si, offset message_txt */
 153        "\xac"          /* 05f:         lodsb */
 154        "\x22\xc0"      /* 060:         and   al, al */
 155        "\x74\x0b"      /* 062:         jz    key_press */
 156        "\x56"          /* 064:         push  si */
 157        "\xb4\x0e"      /* 065:         mov   ah, 0eh */
 158        "\xbb\x07\x00"  /* 067:         mov   bx, 0007h */
 159        "\xcd\x10"      /* 06a:         int   10h */
 160        "\x5e"          /* 06c:         pop   si */
 161        "\xeb\xf0"      /* 06d:         jmp   write_msg */
 162        "\x32\xe4"      /*  key_press:  xor   ah, ah */
 163        "\xcd\x16"      /* 071:         int   16h */
 164        "\xcd\x19"      /* 073:         int   19h */
 165        "\xeb\xfe"      /*  foo:        jmp   foo */
 166        /* 077: message_txt: */
 167        "This is not a bootable disk\r\n";
 168
 169
 170#define MARK_CLUSTER(cluster, value) \
 171        ((uint32_t *)fat)[cluster] = SWAP_LE32(value)
 172
 173void BUG_unsupported_field_size(void);
 174#define STORE_LE(field, value) \
 175do { \
 176        if (sizeof(field) == 4) \
 177                field = SWAP_LE32(value); \
 178        else if (sizeof(field) == 2) \
 179                field = SWAP_LE16(value); \
 180        else if (sizeof(field) == 1) \
 181                field = (value); \
 182        else \
 183                BUG_unsupported_field_size(); \
 184} while (0)
 185
 186/* compat:
 187 * mkdosfs 2.11 (12 Mar 2005)
 188 * Usage: mkdosfs [-A] [-c] [-C] [-v] [-I] [-l bad-block-file]
 189 *        [-b backup-boot-sector]
 190 *        [-m boot-msg-file] [-n volume-name] [-i volume-id]
 191 *        [-s sectors-per-cluster] [-S logical-sector-size]
 192 *        [-f number-of-FATs]
 193 *        [-h hidden-sectors] [-F fat-size] [-r root-dir-entries]
 194 *        [-R reserved-sectors]
 195 *        /dev/name [blocks]
 196 */
 197int mkfs_vfat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 198int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 199{
 200        struct stat st;
 201        const char *volume_label = "";
 202        char *buf;
 203        char *device_name;
 204        uoff_t volume_size_bytes;
 205        uoff_t volume_size_sect;
 206        uint32_t total_clust;
 207        uint32_t volume_id;
 208        int dev;
 209        unsigned bytes_per_sect;
 210        unsigned sect_per_fat;
 211        unsigned opts;
 212        uint16_t sect_per_track;
 213        uint8_t media_byte;
 214        uint8_t sect_per_clust;
 215        uint8_t heads;
 216        enum {
 217                OPT_A = 1 << 0,  // [IGNORED] atari format
 218                OPT_b = 1 << 1,  // [IGNORED] location of backup boot sector
 219                OPT_c = 1 << 2,  // [IGNORED] check filesystem
 220                OPT_C = 1 << 3,  // [IGNORED] create a new file
 221                OPT_f = 1 << 4,  // [IGNORED] number of FATs
 222                OPT_F = 1 << 5,  // [IGNORED, implied 32] choose FAT size
 223                OPT_h = 1 << 6,  // [IGNORED] number of hidden sectors
 224                OPT_I = 1 << 7,  // [IGNORED] don't bark at entire disk devices
 225                OPT_i = 1 << 8,  // [IGNORED] volume ID
 226                OPT_l = 1 << 9,  // [IGNORED] bad block filename
 227                OPT_m = 1 << 10, // [IGNORED] message file
 228                OPT_n = 1 << 11, // volume label
 229                OPT_r = 1 << 12, // [IGNORED] root directory entries
 230                OPT_R = 1 << 13, // [IGNORED] number of reserved sectors
 231                OPT_s = 1 << 14, // [IGNORED] sectors per cluster
 232                OPT_S = 1 << 15, // [IGNORED] sector size
 233                OPT_v = 1 << 16, // verbose
 234        };
 235
 236        opt_complementary = "-1";//:b+:f+:F+:h+:r+:R+:s+:S+:vv:c--l:l--c";
 237        opts = getopt32(argv, "Ab:cCf:F:h:Ii:l:m:n:r:R:s:S:v",
 238                NULL, NULL, NULL, NULL, NULL,
 239                NULL, NULL, &volume_label, NULL, NULL, NULL, NULL);
 240        argv += optind;
 241
 242        // cache device name
 243        device_name = argv[0];
 244        // default volume ID = creation time
 245        volume_id = time(NULL);
 246
 247        dev = xopen(device_name, O_RDWR);
 248        if (fstat(dev, &st) < 0)
 249                bb_simple_perror_msg_and_die(device_name);
 250
 251        //
 252        // Get image size and sector size
 253        //
 254        bytes_per_sect = SECTOR_SIZE;
 255        if (!S_ISBLK(st.st_mode)) {
 256                if (!S_ISREG(st.st_mode)) {
 257                        if (!argv[1])
 258                                bb_error_msg_and_die("image size must be specified");
 259                }
 260                // not a block device, skip bad sectors check
 261                opts &= ~OPT_c;
 262        } else {
 263                int min_bytes_per_sect;
 264#if 0
 265                unsigned device_num;
 266                // for true block devices we do check sanity
 267                device_num = st.st_rdev & 0xff3f;
 268                // do we allow to format the whole disk device?
 269                if (!(opts & OPT_I) && (
 270                        device_num == 0x0300 || // hda, hdb
 271                        (device_num & 0xff0f) == 0x0800 || // sd
 272                        device_num == 0x0d00 || // xd
 273                        device_num == 0x1600 )  // hdc, hdd
 274                )
 275                        bb_error_msg_and_die("will not try to make filesystem on full-disk device (use -I if wanted)");
 276                // can't work on mounted filesystems
 277                if (find_mount_point(device_name, 0))
 278                        bb_error_msg_and_die("can't format mounted filesystem");
 279#endif
 280                // get true sector size
 281                // (parameter must be int*, not long* or size_t*)
 282                xioctl(dev, BLKSSZGET, &min_bytes_per_sect);
 283                if (min_bytes_per_sect > SECTOR_SIZE) {
 284                        bytes_per_sect = min_bytes_per_sect;
 285                        bb_error_msg("for this device sector size is %u", min_bytes_per_sect);
 286                }
 287        }
 288        volume_size_bytes = get_volume_size_in_bytes(dev, argv[1], 1024, /*extend:*/ 1);
 289        volume_size_sect = volume_size_bytes / bytes_per_sect;
 290
 291        //
 292        // Find out or guess media parameters
 293        //
 294        media_byte = 0xf8;
 295        heads = 255;
 296        sect_per_track = 63;
 297        sect_per_clust = 1;
 298        {
 299                struct hd_geometry geometry;
 300                // size (in sectors), sect (per track), head
 301                struct floppy_struct param;
 302
 303                // N.B. whether to use HDIO_GETGEO or HDIO_REQ?
 304                if (ioctl(dev, HDIO_GETGEO, &geometry) == 0
 305                 && geometry.sectors
 306                 && geometry.heads
 307                ) {
 308                        // hard drive
 309                        sect_per_track = geometry.sectors;
 310                        heads = geometry.heads;
 311
 312 set_cluster_size:
 313                        /* For FAT32, try to do the same as M$'s format command
 314                         * (see http://www.win.tue.nl/~aeb/linux/fs/fat/fatgen103.pdf p. 20):
 315                         * fs size <= 260M: 0.5k clusters
 316                         * fs size <=   8G: 4k clusters
 317                         * fs size <=  16G: 8k clusters
 318                         * fs size >   16G: 16k clusters
 319                         */
 320                        sect_per_clust = 1;
 321                        if (volume_size_bytes >= 260*1024*1024) {
 322                                sect_per_clust = 8;
 323                                /* fight gcc: */
 324                                /* "error: integer overflow in expression" */
 325                                /* "error: right shift count >= width of type" */
 326                                if (sizeof(off_t) > 4) {
 327                                        unsigned t = (volume_size_bytes >> 31 >> 1);
 328                                        if (t >= 8/4)
 329                                                sect_per_clust = 16;
 330                                        if (t >= 16/4)
 331                                                sect_per_clust = 32;
 332                                }
 333                        }
 334                } else {
 335                        // floppy, loop, or regular file
 336                        int not_floppy = ioctl(dev, FDGETPRM, &param);
 337                        if (not_floppy == 0) {
 338                                // floppy disk
 339                                sect_per_track = param.sect;
 340                                heads = param.head;
 341                                volume_size_sect = param.size;
 342                                volume_size_bytes = param.size * SECTOR_SIZE;
 343                        }
 344                        // setup the media descriptor byte
 345                        switch (volume_size_sect) {
 346                        case 2*360:     // 5.25", 2, 9, 40 - 360K
 347                                media_byte = 0xfd;
 348                                break;
 349                        case 2*720:     // 3.5", 2, 9, 80 - 720K
 350                        case 2*1200:    // 5.25", 2, 15, 80 - 1200K
 351                                media_byte = 0xf9;
 352                                break;
 353                        default:        // anything else
 354                                if (not_floppy)
 355                                        goto set_cluster_size;
 356                        case 2*1440:    // 3.5", 2, 18, 80 - 1440K
 357                        case 2*2880:    // 3.5", 2, 36, 80 - 2880K
 358                                media_byte = 0xf0;
 359                                break;
 360                        }
 361                        // not floppy, but size matches floppy exactly.
 362                        // perhaps it is a floppy image.
 363                        // we already set media_byte as if it is a floppy,
 364                        // now set sect_per_track and heads.
 365                        heads = 2;
 366                        sect_per_track = (unsigned)volume_size_sect / 160;
 367                        if (sect_per_track < 9)
 368                                sect_per_track = 9;
 369                }
 370        }
 371
 372        //
 373        // Calculate number of clusters, sectors/cluster, sectors/FAT
 374        // (an initial guess for sect_per_clust should already be set)
 375        //
 376        // "mkdosfs -v -F 32 image5k 5" is the minimum:
 377        // 2 sectors for FATs and 2 data sectors
 378        if ((off_t)(volume_size_sect - reserved_sect) < 4)
 379                bb_error_msg_and_die("the image is too small for FAT32");
 380        sect_per_fat = 1;
 381        while (1) {
 382                while (1) {
 383                        int spf_adj;
 384                        uoff_t tcl = (volume_size_sect - reserved_sect - NUM_FATS * sect_per_fat) / sect_per_clust;
 385                        // tcl may be > MAX_CLUST_32 here, but it may be
 386                        // because sect_per_fat is underestimated,
 387                        // and with increased sect_per_fat it still may become
 388                        // <= MAX_CLUST_32. Therefore, we do not check
 389                        // against MAX_CLUST_32, but against a bigger const:
 390                        if (tcl > 0x80ffffff)
 391                                goto next;
 392                        total_clust = tcl; // fits in uint32_t
 393                        // Every cluster needs 4 bytes in FAT. +2 entries since
 394                        // FAT has space for non-existent clusters 0 and 1.
 395                        // Let's see how many sectors that needs.
 396                        //May overflow at "*4":
 397                        //spf_adj = ((total_clust+2) * 4 + bytes_per_sect-1) / bytes_per_sect - sect_per_fat;
 398                        //Same in the more obscure, non-overflowing form:
 399                        spf_adj = ((total_clust+2) + (bytes_per_sect/4)-1) / (bytes_per_sect/4) - sect_per_fat;
 400#if 0
 401                        bb_error_msg("sect_per_clust:%u sect_per_fat:%u total_clust:%u",
 402                                        sect_per_clust, sect_per_fat, (int)tcl);
 403                        bb_error_msg("adjust to sect_per_fat:%d", spf_adj);
 404#endif
 405                        if (spf_adj <= 0) {
 406                                // do not need to adjust sect_per_fat.
 407                                // so, was total_clust too big after all?
 408                                if (total_clust <= MAX_CLUST_32)
 409                                        goto found_total_clust; // no
 410                                // yes, total_clust is _a bit_ too big
 411                                goto next;
 412                        }
 413                        // adjust sect_per_fat, go back and recalc total_clust
 414                        // (note: just "sect_per_fat += spf_adj" isn't ok)
 415                        sect_per_fat += ((unsigned)spf_adj / 2) | 1;
 416                }
 417 next:
 418                if (sect_per_clust == 128)
 419                        bb_error_msg_and_die("can't make FAT32 with >128 sectors/cluster");
 420                sect_per_clust *= 2;
 421                sect_per_fat = (sect_per_fat / 2) | 1;
 422        }
 423 found_total_clust:
 424
 425        //
 426        // Print info
 427        //
 428        if (opts & OPT_v) {
 429                fprintf(stderr,
 430                        "Device '%s':\n"
 431                        "heads:%u, sectors/track:%u, bytes/sector:%u\n"
 432                        "media descriptor:%02x\n"
 433                        "total sectors:%"OFF_FMT"u, clusters:%u, sectors/cluster:%u\n"
 434                        "FATs:2, sectors/FAT:%u\n"
 435                        "volumeID:%08x, label:'%s'\n",
 436                        device_name,
 437                        heads, sect_per_track, bytes_per_sect,
 438                        (int)media_byte,
 439                        volume_size_sect, (int)total_clust, (int)sect_per_clust,
 440                        sect_per_fat,
 441                        (int)volume_id, volume_label
 442                );
 443        }
 444
 445        //
 446        // Write filesystem image sequentially (no seeking)
 447        //
 448        {
 449                // (a | b) is poor man's max(a, b)
 450                unsigned bufsize = reserved_sect;
 451                //bufsize |= sect_per_fat; // can be quite large
 452                bufsize |= 2; // use this instead
 453                bufsize |= sect_per_clust;
 454                buf = xzalloc(bufsize * bytes_per_sect);
 455        }
 456
 457        { // boot and fsinfo sectors, and their copies
 458                struct msdos_boot_sector *boot_blk = (void*)buf;
 459                struct fat32_fsinfo *info = (void*)(buf + bytes_per_sect);
 460
 461                strcpy(boot_blk->boot_jump_and_sys_id, "\xeb\x58\x90" "mkdosfs");
 462                STORE_LE(boot_blk->bytes_per_sect, bytes_per_sect);
 463                STORE_LE(boot_blk->sect_per_clust, sect_per_clust);
 464                // cast in needed on big endian to suppress a warning
 465                STORE_LE(boot_blk->reserved_sect, (uint16_t)reserved_sect);
 466                STORE_LE(boot_blk->fats, 2);
 467                //STORE_LE(boot_blk->dir_entries, 0); // for FAT32, stays 0
 468                if (volume_size_sect <= 0xffff)
 469                        STORE_LE(boot_blk->volume_size_sect, volume_size_sect);
 470                STORE_LE(boot_blk->media_byte, media_byte);
 471                // wrong: this would make Linux think that it's fat12/16:
 472                //if (sect_per_fat <= 0xffff)
 473                //      STORE_LE(boot_blk->sect_per_fat, sect_per_fat);
 474                // works:
 475                //STORE_LE(boot_blk->sect_per_fat, 0);
 476                STORE_LE(boot_blk->sect_per_track, sect_per_track);
 477                STORE_LE(boot_blk->heads, heads);
 478                //STORE_LE(boot_blk->hidden, 0);
 479                STORE_LE(boot_blk->fat32_volume_size_sect, volume_size_sect);
 480                STORE_LE(boot_blk->fat32_sect_per_fat, sect_per_fat);
 481                //STORE_LE(boot_blk->fat32_flags, 0);
 482                //STORE_LE(boot_blk->fat32_version[2], 0,0);
 483                STORE_LE(boot_blk->fat32_root_cluster, 2);
 484                STORE_LE(boot_blk->fat32_info_sector, info_sector_number);
 485                STORE_LE(boot_blk->fat32_backup_boot, backup_boot_sector);
 486                //STORE_LE(boot_blk->reserved2[3], 0,0,0);
 487                STORE_LE(boot_blk->vi.ext_boot_sign, 0x29);
 488                STORE_LE(boot_blk->vi.volume_id32, volume_id);
 489                strncpy(boot_blk->vi.fs_type, "FAT32   ", sizeof(boot_blk->vi.fs_type));
 490                strncpy(boot_blk->vi.volume_label, volume_label, sizeof(boot_blk->vi.volume_label));
 491                memcpy(boot_blk->boot_code, boot_code, sizeof(boot_code));
 492                STORE_LE(boot_blk->boot_sign, BOOT_SIGN);
 493
 494                STORE_LE(info->signature1, FAT_FSINFO_SIG1);
 495                STORE_LE(info->signature2, FAT_FSINFO_SIG2);
 496                // we've allocated cluster 2 for the root dir
 497                STORE_LE(info->free_clusters, (total_clust - 1));
 498                STORE_LE(info->next_cluster, 2);
 499                STORE_LE(info->boot_sign, BOOT_SIGN);
 500
 501                // 1st copy
 502                xwrite(dev, buf, bytes_per_sect * backup_boot_sector);
 503                // 2nd copy and possibly zero sectors
 504                xwrite(dev, buf, bytes_per_sect * (reserved_sect - backup_boot_sector));
 505        }
 506
 507        { // file allocation tables
 508                unsigned i,j;
 509                unsigned char *fat = (void*)buf;
 510
 511                memset(buf, 0, bytes_per_sect * 2);
 512                // initial FAT entries
 513                MARK_CLUSTER(0, 0x0fffff00 | media_byte);
 514                MARK_CLUSTER(1, 0xffffffff);
 515                // mark cluster 2 as EOF (used for root dir)
 516                MARK_CLUSTER(2, EOF_FAT32);
 517                for (i = 0; i < NUM_FATS; i++) {
 518                        xwrite(dev, buf, bytes_per_sect);
 519                        for (j = 1; j < sect_per_fat; j++)
 520                                xwrite(dev, buf + bytes_per_sect, bytes_per_sect);
 521                }
 522        }
 523
 524        // root directory
 525        // empty directory is just a set of zero bytes
 526        memset(buf, 0, sect_per_clust * bytes_per_sect);
 527        if (volume_label[0]) {
 528                // create dir entry for volume_label
 529                struct msdos_dir_entry *de;
 530#if 0
 531                struct tm tm_time;
 532                uint16_t t, d;
 533#endif
 534                de = (void*)buf;
 535                strncpy(de->name, volume_label, sizeof(de->name));
 536                STORE_LE(de->attr, ATTR_VOLUME);
 537#if 0
 538                localtime_r(&create_time, &tm_time);
 539                t = (tm_time.tm_sec >> 1) + (tm_time.tm_min << 5) + (tm_time.tm_hour << 11);
 540                d = tm_time.tm_mday + ((tm_time.tm_mon+1) << 5) + ((tm_time.tm_year-80) << 9);
 541                STORE_LE(de->time, t);
 542                STORE_LE(de->date, d);
 543                //STORE_LE(de->ctime_cs, 0);
 544                de->ctime = de->time;
 545                de->cdate = de->date;
 546                de->adate = de->date;
 547#endif
 548        }
 549        xwrite(dev, buf, sect_per_clust * bytes_per_sect);
 550
 551#if 0
 552        if (opts & OPT_c) {
 553                uoff_t volume_size_blocks;
 554                unsigned start_data_sector;
 555                unsigned start_data_block;
 556                unsigned badblocks = 0;
 557                int try, got;
 558                off_t currently_testing;
 559                char *blkbuf = xmalloc(BLOCK_SIZE * TEST_BUFFER_BLOCKS);
 560
 561                volume_size_blocks = (volume_size_bytes >> BLOCK_SIZE_BITS);
 562                // N.B. the two following vars are in hard sectors, i.e. SECTOR_SIZE byte sectors!
 563                start_data_sector = (reserved_sect + NUM_FATS * sect_per_fat) * (bytes_per_sect / SECTOR_SIZE);
 564                start_data_block = (start_data_sector + SECTORS_PER_BLOCK - 1) / SECTORS_PER_BLOCK;
 565
 566                bb_info_msg("searching for bad blocks ");
 567                currently_testing = 0;
 568                try = TEST_BUFFER_BLOCKS;
 569                while (currently_testing < volume_size_blocks) {
 570                        if (currently_testing + try > volume_size_blocks)
 571                                try = volume_size_blocks - currently_testing;
 572                        // perform a test on a block. return the number of blocks
 573                        // that could be read successfully.
 574                        // seek to the correct location
 575                        xlseek(dev, currently_testing * BLOCK_SIZE, SEEK_SET);
 576                        // try reading
 577                        got = read(dev, blkbuf, try * BLOCK_SIZE);
 578                        if (got < 0)
 579                                got = 0;
 580                        if (got & (BLOCK_SIZE - 1))
 581                                bb_error_msg("unexpected values in do_check: probably bugs");
 582                        got /= BLOCK_SIZE;
 583                        currently_testing += got;
 584                        if (got == try) {
 585                                try = TEST_BUFFER_BLOCKS;
 586                                continue;
 587                        }
 588                        try = 1;
 589                        if (currently_testing < start_data_block)
 590                                bb_error_msg_and_die("bad blocks before data-area: cannot make fs");
 591
 592                        // mark all of the sectors in the block as bad
 593                        for (i = 0; i < SECTORS_PER_BLOCK; i++) {
 594                                int cluster = (currently_testing * SECTORS_PER_BLOCK + i - start_data_sector) / (int) (sect_per_clust) / (bytes_per_sect / SECTOR_SIZE);
 595                                if (cluster < 0)
 596                                        bb_error_msg_and_die("invalid cluster number in mark_sector: probably bug!");
 597                                MARK_CLUSTER(cluster, BAD_FAT32);
 598                        }
 599                        badblocks++;
 600                        currently_testing++;
 601                }
 602                free(blkbuf);
 603                if (badblocks)
 604                        bb_info_msg("%d bad block(s)", badblocks);
 605        }
 606#endif
 607
 608        // cleanup
 609        if (ENABLE_FEATURE_CLEAN_UP) {
 610                free(buf);
 611                close(dev);
 612        }
 613
 614        return 0;
 615}
 616