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 source tree.
   9 */
  10
  11//usage:#define mkfs_vfat_trivial_usage
  12//usage:       "[-v] [-n LABEL] BLOCKDEV [KBYTES]"
  13/* Accepted but ignored:
  14       "[-c] [-C] [-I] [-l bad-block-file] [-b backup-boot-sector] "
  15       "[-m boot-msg-file] [-i volume-id] "
  16       "[-s sectors-per-cluster] [-S logical-sector-size] [-f number-of-FATs] "
  17       "[-h hidden-sectors] [-F fat-size] [-r root-dir-entries] [-R reserved-sectors] "
  18*/
  19//usage:#define mkfs_vfat_full_usage "\n\n"
  20//usage:       "Make a FAT32 filesystem\n"
  21/* //usage:  "\n        -c      Check device for bad blocks" */
  22//usage:     "\n        -v      Verbose"
  23/* //usage:  "\n        -I      Allow to use entire disk device (e.g. /dev/hda)" */
  24//usage:     "\n        -n LBL  Volume label"
  25
  26#include "libbb.h"
  27
  28#include <linux/hdreg.h> /* HDIO_GETGEO */
  29#include <linux/fd.h>    /* FDGETPRM */
  30#include <sys/mount.h>   /* BLKSSZGET */
  31#if !defined(BLKSSZGET)
  32# define BLKSSZGET _IO(0x12, 104)
  33#endif
  34//#include <linux/msdos_fs.h>
  35
  36#define SECTOR_SIZE             512
  37
  38#define SECTORS_PER_BLOCK       (BLOCK_SIZE / SECTOR_SIZE)
  39
  40// M$ says the high 4 bits of a FAT32 FAT entry are reserved
  41#define EOF_FAT32       0x0FFFFFF8
  42#define BAD_FAT32       0x0FFFFFF7
  43#define MAX_CLUST_32    0x0FFFFFF0
  44
  45#define ATTR_VOLUME     8
  46
  47#define NUM_FATS        2
  48
  49/* FAT32 filesystem looks like this:
  50 * sector -nn...-1: "hidden" sectors, all sectors before this partition
  51 * (-h hidden-sectors sets it. Useful only for boot loaders,
  52 *  they need to know _disk_ offset in order to be able to correctly
  53 *  address sectors relative to start of disk)
  54 * sector 0: boot sector
  55 * sector 1: info sector
  56 * sector 2: set aside for boot code which didn't fit into sector 0
  57 * ...(zero-filled sectors)...
  58 * sector B: backup copy of sector 0 [B set by -b backup-boot-sector]
  59 * sector B+1: backup copy of sector 1
  60 * sector B+2: backup copy of sector 2
  61 * ...(zero-filled sectors)...
  62 * sector R: FAT#1 [R set by -R reserved-sectors]
  63 * ...(FAT#1)...
  64 * sector R+fat_size: FAT#2
  65 * ...(FAT#2)...
  66 * sector R+fat_size*2: cluster #2
  67 * ...(cluster #2)...
  68 * sector R+fat_size*2+clust_size: cluster #3
  69 * ...(the rest is filled by clusters till the end)...
  70 */
  71
  72enum {
  73// Perhaps this should remain constant
  74        info_sector_number = 1,
  75// TODO: make these cmdline options
  76// dont forget sanity check: backup_boot_sector + 3 <= reserved_sect
  77        backup_boot_sector = 3,
  78        reserved_sect      = 6,
  79};
  80
  81// how many blocks we try to read while testing
  82#define TEST_BUFFER_BLOCKS      16
  83
  84struct msdos_dir_entry {
  85        char     name[11];       /* 000 name and extension */
  86        uint8_t  attr;           /* 00b attribute bits */
  87        uint8_t  lcase;          /* 00c case for base and extension */
  88        uint8_t  ctime_cs;       /* 00d creation time, centiseconds (0-199) */
  89        uint16_t ctime;          /* 00e creation time */
  90        uint16_t cdate;          /* 010 creation date */
  91        uint16_t adate;          /* 012 last access date */
  92        uint16_t starthi;        /* 014 high 16 bits of cluster in FAT32 */
  93        uint16_t time;           /* 016 time */
  94        uint16_t date;           /* 018 date */
  95        uint16_t start;          /* 01a first cluster */
  96        uint32_t size;           /* 01c file size in bytes */
  97} PACKED;
  98
  99/* Example of boot sector's beginning:
 1000000  eb 58 90 4d 53 57 49 4e  34 2e 31 00 02 08 26 00  |...MSWIN4.1...&.|
 1010010  02 00 00 00 00 f8 00 00  3f 00 ff 00 3f 00 00 00  |........?...?...|
 1020020  54 9b d0 00 0d 34 00 00  00 00 00 00 02 00 00 00  |T....4..........|
 1030030  01 00 06 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 1040040  80 00 29 71 df 51 e0 4e  4f 20 4e 41 4d 45 20 20  |..)q.Q.NO NAME  |
 1050050  20 20 46 41 54 33 32 20  20 20 33 c9 8e d1 bc f4  |  FAT32   3.....|
 106*/
 107struct msdos_volume_info { /* (offsets are relative to start of boot sector) */
 108        uint8_t  drive_number;    /* 040 BIOS drive number */
 109        uint8_t  reserved;        /* 041 unused */
 110        uint8_t  ext_boot_sign;   /* 042 0x29 if fields below exist (DOS 3.3+) */
 111        uint32_t volume_id32;     /* 043 volume ID number */
 112        char     volume_label[11];/* 047 volume label */
 113        char     fs_type[8];      /* 052 typically "FATnn" */
 114} PACKED;                         /* 05a end. Total size 26 (0x1a) bytes */
 115
 116struct msdos_boot_sector {
 117        /* We use strcpy to fill both, and gcc-4.4.x complains if they are separate */
 118        char     boot_jump_and_sys_id[3+8]; /* 000 short or near jump instruction */
 119        /*char   system_id[8];*/     /* 003 name - can be used to special case partition manager volumes */
 120        uint16_t bytes_per_sect;     /* 00b bytes per logical sector */
 121        uint8_t  sect_per_clust;     /* 00d sectors/cluster */
 122        uint16_t reserved_sect;      /* 00e reserved sectors (sector offset of 1st FAT relative to volume start) */
 123        uint8_t  fats;               /* 010 number of FATs */
 124        uint16_t dir_entries;        /* 011 root directory entries */
 125        uint16_t volume_size_sect;   /* 013 volume size in sectors */
 126        uint8_t  media_byte;         /* 015 media code */
 127        uint16_t sect_per_fat;       /* 016 sectors/FAT */
 128        uint16_t sect_per_track;     /* 018 sectors per track */
 129        uint16_t heads;              /* 01a number of heads */
 130        uint32_t hidden;             /* 01c hidden sectors (sector offset of volume within physical disk) */
 131        uint32_t fat32_volume_size_sect; /* 020 volume size in sectors (if volume_size_sect == 0) */
 132        uint32_t fat32_sect_per_fat; /* 024 sectors/FAT */
 133        uint16_t fat32_flags;        /* 028 bit 8: fat mirroring, low 4: active fat */
 134        uint8_t  fat32_version[2];   /* 02a major, minor filesystem version (I see 0,0) */
 135        uint32_t fat32_root_cluster; /* 02c first cluster in root directory */
 136        uint16_t fat32_info_sector;  /* 030 filesystem info sector (usually 1) */
 137        uint16_t fat32_backup_boot;  /* 032 backup boot sector (usually 6) */
 138        uint32_t reserved2[3];       /* 034 unused */
 139        struct msdos_volume_info vi; /* 040 */
 140        char     boot_code[0x200 - 0x5a - 2]; /* 05a */
 141#define BOOT_SIGN 0xAA55
 142        uint16_t boot_sign;          /* 1fe */
 143} PACKED;
 144
 145#define FAT_FSINFO_SIG1 0x41615252
 146#define FAT_FSINFO_SIG2 0x61417272
 147struct fat32_fsinfo {
 148        uint32_t signature1;         /* 0x52,0x52,0x41,0x61, "RRaA" */
 149        uint32_t reserved1[128 - 8];
 150        uint32_t signature2;         /* 0x72,0x72,0x61,0x41, "rrAa" */
 151        uint32_t free_clusters;      /* free cluster count.  -1 if unknown */
 152        uint32_t next_cluster;       /* most recently allocated cluster */
 153        uint32_t reserved2[3];
 154        uint16_t reserved3;          /* 1fc */
 155        uint16_t boot_sign;          /* 1fe */
 156} PACKED;
 157
 158struct bug_check {
 159        char BUG1[sizeof(struct msdos_dir_entry  ) == 0x20 ? 1 : -1];
 160        char BUG2[sizeof(struct msdos_volume_info) == 0x1a ? 1 : -1];
 161        char BUG3[sizeof(struct msdos_boot_sector) == 0x200 ? 1 : -1];
 162        char BUG4[sizeof(struct fat32_fsinfo     ) == 0x200 ? 1 : -1];
 163};
 164
 165static const char boot_code[] ALIGN1 =
 166        "\x0e"          /* 05a:         push  cs */
 167        "\x1f"          /* 05b:         pop   ds */
 168        "\xbe\x77\x7c"  /*  write_msg:  mov   si, offset message_txt */
 169        "\xac"          /* 05f:         lodsb */
 170        "\x22\xc0"      /* 060:         and   al, al */
 171        "\x74\x0b"      /* 062:         jz    key_press */
 172        "\x56"          /* 064:         push  si */
 173        "\xb4\x0e"      /* 065:         mov   ah, 0eh */
 174        "\xbb\x07\x00"  /* 067:         mov   bx, 0007h */
 175        "\xcd\x10"      /* 06a:         int   10h */
 176        "\x5e"          /* 06c:         pop   si */
 177        "\xeb\xf0"      /* 06d:         jmp   write_msg */
 178        "\x32\xe4"      /*  key_press:  xor   ah, ah */
 179        "\xcd\x16"      /* 071:         int   16h */
 180        "\xcd\x19"      /* 073:         int   19h */
 181        "\xeb\xfe"      /*  foo:        jmp   foo */
 182        /* 077: message_txt: */
 183        "This is not a bootable disk\r\n";
 184
 185
 186#define MARK_CLUSTER(cluster, value) \
 187        ((uint32_t *)fat)[cluster] = SWAP_LE32(value)
 188
 189void BUG_unsupported_field_size(void);
 190#define STORE_LE(field, value) \
 191do { \
 192        if (sizeof(field) == 4) \
 193                field = SWAP_LE32(value); \
 194        else if (sizeof(field) == 2) \
 195                field = SWAP_LE16(value); \
 196        else if (sizeof(field) == 1) \
 197                field = (value); \
 198        else \
 199                BUG_unsupported_field_size(); \
 200} while (0)
 201
 202/* compat:
 203 * mkdosfs 2.11 (12 Mar 2005)
 204 * Usage: mkdosfs [-A] [-c] [-C] [-v] [-I] [-l bad-block-file]
 205 *        [-b backup-boot-sector]
 206 *        [-m boot-msg-file] [-n volume-name] [-i volume-id]
 207 *        [-s sectors-per-cluster] [-S logical-sector-size]
 208 *        [-f number-of-FATs]
 209 *        [-h hidden-sectors] [-F fat-size] [-r root-dir-entries]
 210 *        [-R reserved-sectors]
 211 *        /dev/name [blocks]
 212 */
 213int mkfs_vfat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 214int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 215{
 216        struct stat st;
 217        const char *volume_label = "";
 218        char *buf;
 219        char *device_name;
 220        uoff_t volume_size_bytes;
 221        uoff_t volume_size_sect;
 222        uint32_t total_clust;
 223        uint32_t volume_id;
 224        int dev;
 225        unsigned bytes_per_sect;
 226        unsigned sect_per_fat;
 227        unsigned opts;
 228        uint16_t sect_per_track;
 229        uint8_t media_byte;
 230        uint8_t sect_per_clust;
 231        uint8_t heads;
 232        enum {
 233                OPT_A = 1 << 0,  // [IGNORED] atari format
 234                OPT_b = 1 << 1,  // [IGNORED] location of backup boot sector
 235                OPT_c = 1 << 2,  // [IGNORED] check filesystem
 236                OPT_C = 1 << 3,  // [IGNORED] create a new file
 237                OPT_f = 1 << 4,  // [IGNORED] number of FATs
 238                OPT_F = 1 << 5,  // [IGNORED, implied 32] choose FAT size
 239                OPT_h = 1 << 6,  // [IGNORED] number of hidden sectors
 240                OPT_I = 1 << 7,  // [IGNORED] don't bark at entire disk devices
 241                OPT_i = 1 << 8,  // [IGNORED] volume ID
 242                OPT_l = 1 << 9,  // [IGNORED] bad block filename
 243                OPT_m = 1 << 10, // [IGNORED] message file
 244                OPT_n = 1 << 11, // volume label
 245                OPT_r = 1 << 12, // [IGNORED] root directory entries
 246                OPT_R = 1 << 13, // [IGNORED] number of reserved sectors
 247                OPT_s = 1 << 14, // [IGNORED] sectors per cluster
 248                OPT_S = 1 << 15, // [IGNORED] sector size
 249                OPT_v = 1 << 16, // verbose
 250        };
 251
 252        opt_complementary = "-1";//:b+:f+:F+:h+:r+:R+:s+:S+:vv:c--l:l--c";
 253        opts = getopt32(argv, "Ab:cCf:F:h:Ii:l:m:n:r:R:s:S:v",
 254                NULL, NULL, NULL, NULL, NULL,
 255                NULL, NULL, &volume_label, NULL, NULL, NULL, NULL);
 256        argv += optind;
 257
 258        // cache device name
 259        device_name = argv[0];
 260        // default volume ID = creation time
 261        volume_id = time(NULL);
 262
 263        dev = xopen(device_name, O_RDWR);
 264        xfstat(dev, &st, device_name);
 265
 266        //
 267        // Get image size and sector size
 268        //
 269        bytes_per_sect = SECTOR_SIZE;
 270        if (!S_ISBLK(st.st_mode)) {
 271                if (!S_ISREG(st.st_mode)) {
 272                        if (!argv[1])
 273                                bb_error_msg_and_die("image size must be specified");
 274                }
 275                // not a block device, skip bad sectors check
 276                opts &= ~OPT_c;
 277        } else {
 278                int min_bytes_per_sect;
 279#if 0
 280                unsigned device_num;
 281                // for true block devices we do check sanity
 282                device_num = st.st_rdev & 0xff3f;
 283                // do we allow to format the whole disk device?
 284                if (!(opts & OPT_I) && (
 285                        device_num == 0x0300 || // hda, hdb
 286                        (device_num & 0xff0f) == 0x0800 || // sd
 287                        device_num == 0x0d00 || // xd
 288                        device_num == 0x1600 )  // hdc, hdd
 289                )
 290                        bb_error_msg_and_die("will not try to make filesystem on full-disk device (use -I if wanted)");
 291                // can't work on mounted filesystems
 292                if (find_mount_point(device_name, 0))
 293                        bb_error_msg_and_die("can't format mounted filesystem");
 294#endif
 295                // get true sector size
 296                // (parameter must be int*, not long* or size_t*)
 297                xioctl(dev, BLKSSZGET, &min_bytes_per_sect);
 298                if (min_bytes_per_sect > SECTOR_SIZE) {
 299                        bytes_per_sect = min_bytes_per_sect;
 300                        bb_error_msg("for this device sector size is %u", min_bytes_per_sect);
 301                }
 302        }
 303        volume_size_bytes = get_volume_size_in_bytes(dev, argv[1], 1024, /*extend:*/ 1);
 304        volume_size_sect = volume_size_bytes / bytes_per_sect;
 305
 306        //
 307        // Find out or guess media parameters
 308        //
 309        media_byte = 0xf8;
 310        heads = 255;
 311        sect_per_track = 63;
 312        sect_per_clust = 1;
 313        {
 314                struct hd_geometry geometry;
 315                // size (in sectors), sect (per track), head
 316                struct floppy_struct param;
 317
 318                // N.B. whether to use HDIO_GETGEO or HDIO_REQ?
 319                if (ioctl(dev, HDIO_GETGEO, &geometry) == 0
 320                 && geometry.sectors
 321                 && geometry.heads
 322                ) {
 323                        // hard drive
 324                        sect_per_track = geometry.sectors;
 325                        heads = geometry.heads;
 326
 327 set_cluster_size:
 328                        /* For FAT32, try to do the same as M$'s format command
 329                         * (see http://www.win.tue.nl/~aeb/linux/fs/fat/fatgen103.pdf p. 20):
 330                         * fs size <= 260M: 0.5k clusters
 331                         * fs size <=   8G: 4k clusters
 332                         * fs size <=  16G: 8k clusters
 333                         * fs size >   16G: 16k clusters
 334                         */
 335                        sect_per_clust = 1;
 336                        if (volume_size_bytes >= 260*1024*1024) {
 337                                sect_per_clust = 8;
 338                                /* fight gcc: */
 339                                /* "error: integer overflow in expression" */
 340                                /* "error: right shift count >= width of type" */
 341                                if (sizeof(off_t) > 4) {
 342                                        unsigned t = (volume_size_bytes >> 31 >> 1);
 343                                        if (t >= 8/4)
 344                                                sect_per_clust = 16;
 345                                        if (t >= 16/4)
 346                                                sect_per_clust = 32;
 347                                }
 348                        }
 349                } else {
 350                        // floppy, loop, or regular file
 351                        int not_floppy = ioctl(dev, FDGETPRM, &param);
 352                        if (not_floppy == 0) {
 353                                // floppy disk
 354                                sect_per_track = param.sect;
 355                                heads = param.head;
 356                                volume_size_sect = param.size;
 357                                volume_size_bytes = param.size * SECTOR_SIZE;
 358                        }
 359                        // setup the media descriptor byte
 360                        switch (volume_size_sect) {
 361                        case 2*360:     // 5.25", 2, 9, 40 - 360K
 362                                media_byte = 0xfd;
 363                                break;
 364                        case 2*720:     // 3.5", 2, 9, 80 - 720K
 365                        case 2*1200:    // 5.25", 2, 15, 80 - 1200K
 366                                media_byte = 0xf9;
 367                                break;
 368                        default:        // anything else
 369                                if (not_floppy)
 370                                        goto set_cluster_size;
 371                        case 2*1440:    // 3.5", 2, 18, 80 - 1440K
 372                        case 2*2880:    // 3.5", 2, 36, 80 - 2880K
 373                                media_byte = 0xf0;
 374                                break;
 375                        }
 376                        // not floppy, but size matches floppy exactly.
 377                        // perhaps it is a floppy image.
 378                        // we already set media_byte as if it is a floppy,
 379                        // now set sect_per_track and heads.
 380                        heads = 2;
 381                        sect_per_track = (unsigned)volume_size_sect / 160;
 382                        if (sect_per_track < 9)
 383                                sect_per_track = 9;
 384                }
 385        }
 386
 387        //
 388        // Calculate number of clusters, sectors/cluster, sectors/FAT
 389        // (an initial guess for sect_per_clust should already be set)
 390        //
 391        // "mkdosfs -v -F 32 image5k 5" is the minimum:
 392        // 2 sectors for FATs and 2 data sectors
 393        if ((off_t)(volume_size_sect - reserved_sect) < 4)
 394                bb_error_msg_and_die("the image is too small for FAT32");
 395        sect_per_fat = 1;
 396        while (1) {
 397                while (1) {
 398                        int spf_adj;
 399                        uoff_t tcl = (volume_size_sect - reserved_sect - NUM_FATS * sect_per_fat) / sect_per_clust;
 400                        // tcl may be > MAX_CLUST_32 here, but it may be
 401                        // because sect_per_fat is underestimated,
 402                        // and with increased sect_per_fat it still may become
 403                        // <= MAX_CLUST_32. Therefore, we do not check
 404                        // against MAX_CLUST_32, but against a bigger const:
 405                        if (tcl > 0x80ffffff)
 406                                goto next;
 407                        total_clust = tcl; // fits in uint32_t
 408                        // Every cluster needs 4 bytes in FAT. +2 entries since
 409                        // FAT has space for non-existent clusters 0 and 1.
 410                        // Let's see how many sectors that needs.
 411                        //May overflow at "*4":
 412                        //spf_adj = ((total_clust+2) * 4 + bytes_per_sect-1) / bytes_per_sect - sect_per_fat;
 413                        //Same in the more obscure, non-overflowing form:
 414                        spf_adj = ((total_clust+2) + (bytes_per_sect/4)-1) / (bytes_per_sect/4) - sect_per_fat;
 415#if 0
 416                        bb_error_msg("sect_per_clust:%u sect_per_fat:%u total_clust:%u",
 417                                        sect_per_clust, sect_per_fat, (int)tcl);
 418                        bb_error_msg("adjust to sect_per_fat:%d", spf_adj);
 419#endif
 420                        if (spf_adj <= 0) {
 421                                // do not need to adjust sect_per_fat.
 422                                // so, was total_clust too big after all?
 423                                if (total_clust <= MAX_CLUST_32)
 424                                        goto found_total_clust; // no
 425                                // yes, total_clust is _a bit_ too big
 426                                goto next;
 427                        }
 428                        // adjust sect_per_fat, go back and recalc total_clust
 429                        // (note: just "sect_per_fat += spf_adj" isn't ok)
 430                        sect_per_fat += ((unsigned)spf_adj / 2) | 1;
 431                }
 432 next:
 433                if (sect_per_clust == 128)
 434                        bb_error_msg_and_die("can't make FAT32 with >128 sectors/cluster");
 435                sect_per_clust *= 2;
 436                sect_per_fat = (sect_per_fat / 2) | 1;
 437        }
 438 found_total_clust:
 439
 440        //
 441        // Print info
 442        //
 443        if (opts & OPT_v) {
 444                fprintf(stderr,
 445                        "Device '%s':\n"
 446                        "heads:%u, sectors/track:%u, bytes/sector:%u\n"
 447                        "media descriptor:%02x\n"
 448                        "total sectors:%"OFF_FMT"u, clusters:%u, sectors/cluster:%u\n"
 449                        "FATs:2, sectors/FAT:%u\n"
 450                        "volumeID:%08x, label:'%s'\n",
 451                        device_name,
 452                        heads, sect_per_track, bytes_per_sect,
 453                        (int)media_byte,
 454                        volume_size_sect, (int)total_clust, (int)sect_per_clust,
 455                        sect_per_fat,
 456                        (int)volume_id, volume_label
 457                );
 458        }
 459
 460        //
 461        // Write filesystem image sequentially (no seeking)
 462        //
 463        {
 464                // (a | b) is poor man's max(a, b)
 465                unsigned bufsize = reserved_sect;
 466                //bufsize |= sect_per_fat; // can be quite large
 467                bufsize |= 2; // use this instead
 468                bufsize |= sect_per_clust;
 469                buf = xzalloc(bufsize * bytes_per_sect);
 470        }
 471
 472        { // boot and fsinfo sectors, and their copies
 473                struct msdos_boot_sector *boot_blk = (void*)buf;
 474                struct fat32_fsinfo *info = (void*)(buf + bytes_per_sect);
 475
 476                strcpy(boot_blk->boot_jump_and_sys_id, "\xeb\x58\x90" "mkdosfs");
 477                STORE_LE(boot_blk->bytes_per_sect, bytes_per_sect);
 478                STORE_LE(boot_blk->sect_per_clust, sect_per_clust);
 479                // cast in needed on big endian to suppress a warning
 480                STORE_LE(boot_blk->reserved_sect, (uint16_t)reserved_sect);
 481                STORE_LE(boot_blk->fats, 2);
 482                //STORE_LE(boot_blk->dir_entries, 0); // for FAT32, stays 0
 483                if (volume_size_sect <= 0xffff)
 484                        STORE_LE(boot_blk->volume_size_sect, volume_size_sect);
 485                STORE_LE(boot_blk->media_byte, media_byte);
 486                // wrong: this would make Linux think that it's fat12/16:
 487                //if (sect_per_fat <= 0xffff)
 488                //      STORE_LE(boot_blk->sect_per_fat, sect_per_fat);
 489                // works:
 490                //STORE_LE(boot_blk->sect_per_fat, 0);
 491                STORE_LE(boot_blk->sect_per_track, sect_per_track);
 492                STORE_LE(boot_blk->heads, heads);
 493                //STORE_LE(boot_blk->hidden, 0);
 494                STORE_LE(boot_blk->fat32_volume_size_sect, volume_size_sect);
 495                STORE_LE(boot_blk->fat32_sect_per_fat, sect_per_fat);
 496                //STORE_LE(boot_blk->fat32_flags, 0);
 497                //STORE_LE(boot_blk->fat32_version[2], 0,0);
 498                STORE_LE(boot_blk->fat32_root_cluster, 2);
 499                STORE_LE(boot_blk->fat32_info_sector, info_sector_number);
 500                STORE_LE(boot_blk->fat32_backup_boot, backup_boot_sector);
 501                //STORE_LE(boot_blk->reserved2[3], 0,0,0);
 502                STORE_LE(boot_blk->vi.ext_boot_sign, 0x29);
 503                STORE_LE(boot_blk->vi.volume_id32, volume_id);
 504                strncpy(boot_blk->vi.fs_type, "FAT32   ", sizeof(boot_blk->vi.fs_type));
 505                strncpy(boot_blk->vi.volume_label, volume_label, sizeof(boot_blk->vi.volume_label));
 506                memcpy(boot_blk->boot_code, boot_code, sizeof(boot_code));
 507                STORE_LE(boot_blk->boot_sign, BOOT_SIGN);
 508
 509                STORE_LE(info->signature1, FAT_FSINFO_SIG1);
 510                STORE_LE(info->signature2, FAT_FSINFO_SIG2);
 511                // we've allocated cluster 2 for the root dir
 512                STORE_LE(info->free_clusters, (total_clust - 1));
 513                STORE_LE(info->next_cluster, 2);
 514                STORE_LE(info->boot_sign, BOOT_SIGN);
 515
 516                // 1st copy
 517                xwrite(dev, buf, bytes_per_sect * backup_boot_sector);
 518                // 2nd copy and possibly zero sectors
 519                xwrite(dev, buf, bytes_per_sect * (reserved_sect - backup_boot_sector));
 520        }
 521
 522        { // file allocation tables
 523                unsigned i,j;
 524                unsigned char *fat = (void*)buf;
 525
 526                memset(buf, 0, bytes_per_sect * 2);
 527                // initial FAT entries
 528                MARK_CLUSTER(0, 0x0fffff00 | media_byte);
 529                MARK_CLUSTER(1, 0xffffffff);
 530                // mark cluster 2 as EOF (used for root dir)
 531                MARK_CLUSTER(2, EOF_FAT32);
 532                for (i = 0; i < NUM_FATS; i++) {
 533                        xwrite(dev, buf, bytes_per_sect);
 534                        for (j = 1; j < sect_per_fat; j++)
 535                                xwrite(dev, buf + bytes_per_sect, bytes_per_sect);
 536                }
 537        }
 538
 539        // root directory
 540        // empty directory is just a set of zero bytes
 541        memset(buf, 0, sect_per_clust * bytes_per_sect);
 542        if (volume_label[0]) {
 543                // create dir entry for volume_label
 544                struct msdos_dir_entry *de;
 545#if 0
 546                struct tm tm_time;
 547                uint16_t t, d;
 548#endif
 549                de = (void*)buf;
 550                strncpy(de->name, volume_label, sizeof(de->name));
 551                STORE_LE(de->attr, ATTR_VOLUME);
 552#if 0
 553                localtime_r(&create_time, &tm_time);
 554                t = (tm_time.tm_sec >> 1) + (tm_time.tm_min << 5) + (tm_time.tm_hour << 11);
 555                d = tm_time.tm_mday + ((tm_time.tm_mon+1) << 5) + ((tm_time.tm_year-80) << 9);
 556                STORE_LE(de->time, t);
 557                STORE_LE(de->date, d);
 558                //STORE_LE(de->ctime_cs, 0);
 559                de->ctime = de->time;
 560                de->cdate = de->date;
 561                de->adate = de->date;
 562#endif
 563        }
 564        xwrite(dev, buf, sect_per_clust * bytes_per_sect);
 565
 566#if 0
 567        if (opts & OPT_c) {
 568                uoff_t volume_size_blocks;
 569                unsigned start_data_sector;
 570                unsigned start_data_block;
 571                unsigned badblocks = 0;
 572                int try, got;
 573                off_t currently_testing;
 574                char *blkbuf = xmalloc(BLOCK_SIZE * TEST_BUFFER_BLOCKS);
 575
 576                volume_size_blocks = (volume_size_bytes >> BLOCK_SIZE_BITS);
 577                // N.B. the two following vars are in hard sectors, i.e. SECTOR_SIZE byte sectors!
 578                start_data_sector = (reserved_sect + NUM_FATS * sect_per_fat) * (bytes_per_sect / SECTOR_SIZE);
 579                start_data_block = (start_data_sector + SECTORS_PER_BLOCK - 1) / SECTORS_PER_BLOCK;
 580
 581                bb_error_msg("searching for bad blocks");
 582                currently_testing = 0;
 583                try = TEST_BUFFER_BLOCKS;
 584                while (currently_testing < volume_size_blocks) {
 585                        if (currently_testing + try > volume_size_blocks)
 586                                try = volume_size_blocks - currently_testing;
 587                        // perform a test on a block. return the number of blocks
 588                        // that could be read successfully.
 589                        // seek to the correct location
 590                        xlseek(dev, currently_testing * BLOCK_SIZE, SEEK_SET);
 591                        // try reading
 592                        got = read(dev, blkbuf, try * BLOCK_SIZE);
 593                        if (got < 0)
 594                                got = 0;
 595                        if (got & (BLOCK_SIZE - 1))
 596                                bb_error_msg("unexpected values in do_check: probably bugs");
 597                        got /= BLOCK_SIZE;
 598                        currently_testing += got;
 599                        if (got == try) {
 600                                try = TEST_BUFFER_BLOCKS;
 601                                continue;
 602                        }
 603                        try = 1;
 604                        if (currently_testing < start_data_block)
 605                                bb_error_msg_and_die("bad blocks before data-area: cannot make fs");
 606
 607                        // mark all of the sectors in the block as bad
 608                        for (i = 0; i < SECTORS_PER_BLOCK; i++) {
 609                                int cluster = (currently_testing * SECTORS_PER_BLOCK + i - start_data_sector) / (int) (sect_per_clust) / (bytes_per_sect / SECTOR_SIZE);
 610                                if (cluster < 0)
 611                                        bb_error_msg_and_die("invalid cluster number in mark_sector: probably bug!");
 612                                MARK_CLUSTER(cluster, BAD_FAT32);
 613                        }
 614                        badblocks++;
 615                        currently_testing++;
 616                }
 617                free(blkbuf);
 618                if (badblocks)
 619                        bb_error_msg("%d bad block(s)", badblocks);
 620        }
 621#endif
 622
 623        // cleanup
 624        if (ENABLE_FEATURE_CLEAN_UP) {
 625                free(buf);
 626                close(dev);
 627        }
 628
 629        return 0;
 630}
 631