/*      $OpenBSD: mkfs_msdos.c,v 1.7 2022/02/28 16:17:37 krw Exp $      */
/*      $NetBSD: mkfs_msdos.c,v 1.10 2016/04/03 11:00:13 mlelstv Exp $  */

/*
 * Copyright (c) 1998 Robert Nordier
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>  /* powerof2 */
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <signal.h>

#include <util.h>

#include "makefs.h"
#include "msdos/mkfs_msdos.h"

#define MAXU16    0xffff        /* maximum unsigned 16-bit quantity */
#define BPN       4             /* bits per nibble */
#define NPB       2             /* nibbles per byte */

#define DOSMAGIC  0xaa55        /* DOS magic number */
#define MINBPS    512           /* minimum bytes per sector */
#define MAXSPC    128           /* maximum sectors per cluster */
#define MAXNFT    16            /* maximum number of FATs */
#define DEFBLK    4096          /* default block size */
#define DEFBLK16  2048          /* default block size FAT16 */
#define DEFRDE    512           /* default root directory entries */
#define RESFTE    2             /* reserved FAT entries */
#define MINCLS12  1             /* minimum FAT12 clusters */
#define MINCLS16  0xff5         /* minimum FAT16 clusters */
#define MINCLS32  0xfff5        /* minimum FAT32 clusters */
#define MAXCLS12  0xff4         /* maximum FAT12 clusters */
#define MAXCLS16  0xfff4        /* maximum FAT16 clusters */
#define MAXCLS32  0xffffff4     /* maximum FAT32 clusters */

#define mincls(fat_type)  ((fat_type) == 12 ? MINCLS12 :        \
                      (fat_type) == 16 ? MINCLS16 :     \
                                    MINCLS32)

#define maxcls(fat_type)  ((fat_type) == 12 ? MAXCLS12 :        \
                      (fat_type) == 16 ? MAXCLS16 :     \
                                    MAXCLS32)

#define mk1(p, x)                               \
    (p) = (u_int8_t)(x)

#define mk2(p, x)                               \
    (p)[0] = (u_int8_t)(x),                     \
    (p)[1] = (u_int8_t)((x) >> 010)

#define mk4(p, x)                               \
    (p)[0] = (u_int8_t)(x),                     \
    (p)[1] = (u_int8_t)((x) >> 010),            \
    (p)[2] = (u_int8_t)((x) >> 020),            \
    (p)[3] = (u_int8_t)((x) >> 030)

struct bs {
    u_int8_t jmp[3];            /* bootstrap entry point */
    u_int8_t oem[8];            /* OEM name and version */
};

struct bsbpb {
    u_int8_t bps[2];            /* bytes per sector */
    u_int8_t spc;               /* sectors per cluster */
    u_int8_t res[2];            /* reserved sectors */
    u_int8_t nft;               /* number of FATs */
    u_int8_t rde[2];            /* root directory entries */
    u_int8_t sec[2];            /* total sectors */
    u_int8_t mid;               /* media descriptor */
    u_int8_t spf[2];            /* sectors per FAT */
    u_int8_t spt[2];            /* sectors per track */
    u_int8_t hds[2];            /* drive heads */
    u_int8_t hid[4];            /* hidden sectors */
    u_int8_t bsec[4];           /* big total sectors */
};

struct bsxbpb {
    u_int8_t bspf[4];           /* big sectors per FAT */
    u_int8_t xflg[2];           /* FAT control flags */
    u_int8_t vers[2];           /* file system version */
    u_int8_t rdcl[4];           /* root directory start cluster */
    u_int8_t infs[2];           /* file system info sector */
    u_int8_t bkbs[2];           /* backup boot sector */
    u_int8_t rsvd[12];          /* reserved */
};

struct bsx {
    u_int8_t drv;               /* drive number */
    u_int8_t rsvd;              /* reserved */
    u_int8_t sig;               /* extended boot signature */
    u_int8_t volid[4];          /* volume ID number */
    u_int8_t label[11];         /* volume label */
    u_int8_t type[8];           /* file system type */
};

struct de {
    u_int8_t namext[11];        /* name and extension */
    u_int8_t attr;              /* attributes */
    u_int8_t rsvd[10];          /* reserved */
    u_int8_t time[2];           /* creation time */
    u_int8_t date[2];           /* creation date */
    u_int8_t clus[2];           /* starting cluster */
    u_int8_t size[4];           /* size */
};

struct bpb {
    u_int bps;                  /* bytes per sector */
    u_int spc;                  /* sectors per cluster */
    u_int res;                  /* reserved sectors */
    u_int nft;                  /* number of FATs */
    u_int rde;                  /* root directory entries */
    u_int sec;                  /* total sectors */
    u_int mid;                  /* media descriptor */
    u_int spf;                  /* sectors per FAT */
    u_int spt;                  /* sectors per track */
    u_int hds;                  /* drive heads */
    u_int hid;                  /* hidden sectors */
    u_int bsec;                 /* big total sectors */
    u_int bspf;                 /* big sectors per FAT */
    u_int rdcl;                 /* root directory start cluster */
    u_int infs;                 /* file system info sector */
    u_int bkbs;                 /* backup boot sector */
};

#define INIT(a, b, c, d, e, f, g, h, i, j) \
    { .bps = a, .spc = b, .res = c, .nft = d, .rde = e, \
      .sec = f, .mid = g, .spf = h, .spt = i, .hds = j, }
static struct {
    const char *name;
    struct bpb bpb;
} stdfmt[] = {
    {"160",  INIT(512, 1, 1, 2,  64,  320, 0xfe, 1,  8, 1)},
    {"180",  INIT(512, 1, 1, 2,  64,  360, 0xfc, 2,  9, 1)},
    {"320",  INIT(512, 2, 1, 2, 112,  640, 0xff, 1,  8, 2)},
    {"360",  INIT(512, 2, 1, 2, 112,  720, 0xfd, 2,  9, 2)},
    {"640",  INIT(512, 2, 1, 2, 112, 1280, 0xfb, 2,  8, 2)},
    {"720",  INIT(512, 2, 1, 2, 112, 1440, 0xf9, 3,  9, 2)},
    {"1200", INIT(512, 1, 1, 2, 224, 2400, 0xf9, 7, 15, 2)},
    {"1232", INIT(1024,1, 1, 2, 192, 1232, 0xfe, 2,  8, 2)},
    {"1440", INIT(512, 1, 1, 2, 224, 2880, 0xf0, 9, 18, 2)},
    {"2880", INIT(512, 2, 1, 2, 240, 5760, 0xf0, 9, 36, 2)}
};

static u_int8_t bootcode[] = {
    0xfa,                       /* cli              */
    0x31, 0xc0,                 /* xor     ax,ax    */
    0x8e, 0xd0,                 /* mov     ss,ax    */
    0xbc, 0x00, 0x7c,           /* mov     sp,7c00h */
    0xfb,                       /* sti              */
    0x8e, 0xd8,                 /* mov     ds,ax    */
    0xe8, 0x00, 0x00,           /* call    $ + 3    */
    0x5e,                       /* pop     si       */
    0x83, 0xc6, 0x19,           /* add     si,+19h  */
    0xbb, 0x07, 0x00,           /* mov     bx,0007h */
    0xfc,                       /* cld              */
    0xac,                       /* lodsb            */
    0x84, 0xc0,                 /* test    al,al    */
    0x74, 0x06,                 /* jz      $ + 8    */
    0xb4, 0x0e,                 /* mov     ah,0eh   */
    0xcd, 0x10,                 /* int     10h      */
    0xeb, 0xf5,                 /* jmp     $ - 9    */
    0x30, 0xe4,                 /* xor     ah,ah    */
    0xcd, 0x16,                 /* int     16h      */
    0xcd, 0x19,                 /* int     19h      */
    0x0d, 0x0a,
    'N', 'o', 'n', '-', 's', 'y', 's', 't',
    'e', 'm', ' ', 'd', 'i', 's', 'k',
    0x0d, 0x0a,
    'P', 'r', 'e', 's', 's', ' ', 'a', 'n',
    'y', ' ', 'k', 'e', 'y', ' ', 't', 'o',
    ' ', 'r', 'e', 'b', 'o', 'o', 't',
    0x0d, 0x0a,
    0
};

static int got_siginfo = 0; /* received a SIGINFO */

static int getstdfmt(const char *, struct bpb *);
static int getbpbinfo(int, const char *, const char *, int, struct bpb *, int);
static void print_bpb(struct bpb *);
static int ckgeom(const char *, u_int, const char *);
static int oklabel(const char *);
static void mklabel(u_int8_t *, const char *);
static void setstr(u_int8_t *, const char *, size_t);
static void infohandler(int sig);

int
mkfs_msdos(const char *fname, const char *dtype, const struct msdos_options *op)
{
    char buf[PATH_MAX];
    struct stat sb;
    struct timeval tv;
    struct bpb bpb;
    struct tm *tm;
    struct bs *bs;
    struct bsbpb *bsbpb;
    struct bsxbpb *bsxbpb;
    struct bsx *bsx;
    struct de *de;
    u_int8_t *img;
    const char *bname;
    ssize_t n;
    time_t now;
    u_int bss, rds, cls, dir, lsn, x, x1, x2;
    int ch, fd, fd1;
    struct msdos_options o = *op;
    int oflags = O_RDWR | O_CREAT;

    if (o.block_size && o.sectors_per_cluster) {
        warnx("Cannot specify both block size and sectors per cluster");
        return -1;
    }
    if (o.OEM_string && strlen(o.OEM_string) > 8) {
        warnx("%s: bad OEM string", o.OEM_string);
        return -1;
    }
    if (o.create_size) {
        if (o.offset == 0)
                oflags |= O_TRUNC;
        fd = open(fname, oflags, 0644);
        if (fd == -1) {
            warnx("failed to create %s", fname);
            return -1;
        }
        (void)lseek(fd, o.create_size - 1, SEEK_SET);
        if (write(fd, "\0", 1) != 1) {
            warn("failed to set file size");
            return -1;
        }
        (void)lseek(fd, 0, SEEK_SET);
    } else if ((fd = open(fname, O_RDWR)) == -1 ||
        fstat(fd, &sb)) {
        warn("%s", fname);
        return -1;
    }
    if (!S_ISCHR(sb.st_mode) && !o.create_size) {
        warnx("warning, %s is not a character device", fname);
        return -1;
    }
    if (o.offset && o.offset != lseek(fd, o.offset, SEEK_SET)) {
        warnx("cannot seek to %jd", (intmax_t)o.offset);
        return -1;
    }
    memset(&bpb, 0, sizeof(bpb));
    if (o.floppy) {
        if (getstdfmt(o.floppy, &bpb) == -1)
            return -1;
        bpb.bsec = bpb.sec;
        bpb.sec = 0;
        bpb.bspf = bpb.spf;
        bpb.spf = 0;
    }
    if (o.drive_heads)
        bpb.hds = o.drive_heads;
    if (o.sectors_per_track)
        bpb.spt = o.sectors_per_track;
    if (o.bytes_per_sector)
        bpb.bps = o.bytes_per_sector;
    if (o.size)
        bpb.bsec = o.size;
    if (o.hidden_sectors_set)
        bpb.hid = o.hidden_sectors;
    if (!(o.floppy || (o.drive_heads && o.sectors_per_track &&
        o.bytes_per_sector && o.size && o.hidden_sectors_set))) {
        if (getbpbinfo(fd, fname, dtype, o.hidden_sectors_set, &bpb,
            o.create_size != 0) == -1)
            return -1;
        bpb.bsec -= (o.offset / bpb.bps);
        if (bpb.spc == 0) {     /* set defaults */
            /* minimum cluster size */
            switch (o.fat_type) {
            case 12:
                bpb.spc = 1;            /* use 512 bytes */
                x = 2;                  /* up to 2MB */
                break;
            case 16:
                bpb.spc = 1;            /* use 512 bytes */
                x = 32;                 /* up to 32MB */
                break;
            default:
                bpb.spc = 8;            /* use 4k */
                x = 8192;               /* up to 8GB */
                break;
            }
            x1 = howmany(bpb.bsec, (1048576 / 512)); /* -> MB */
            while (bpb.spc < 128 && x < x1) {
                x *= 2;
                bpb.spc *= 2;
            }
        }
    }

    if (o.volume_label && !oklabel(o.volume_label)) {
        warnx("%s: bad volume label", o.volume_label);
        return -1;
    }

    switch (o.fat_type) {
    case 0:
        if (o.floppy)
            o.fat_type = 12;
        else if (!o.directory_entries && (o.info_sector || o.backup_sector))
            o.fat_type = 32;
        break;
    case 12:
    case 16:
        if (o.info_sector) {
            warnx("Cannot specify info sector with FAT%u", o.fat_type);
            return -1;
        }
        if (o.backup_sector) {
            warnx("Cannot specify backup sector with FAT%u", o.fat_type);
            return -1;
        }
        break;
    case 32:
        if (o.directory_entries) {
            warnx("Cannot specify directory entries with FAT32");
            return -1;
        }
        break;
    default:
        warnx("%d: bad FAT type", o.fat_type);
        return -1;
    }
    if (!powerof2(bpb.bps)) {
        warnx("bytes/sector (%u) is not a power of 2", bpb.bps);
        return -1;
    }
    if (bpb.bps < MINBPS) {
        warnx("bytes/sector (%u) is too small; minimum is %u",
             bpb.bps, MINBPS);
        return -1;
    }

    if (o.floppy && o.fat_type == 32)
        bpb.rde = 0;
    if (o.block_size) {
        if (!powerof2(o.block_size)) {
            warnx("block size (%u) is not a power of 2", o.block_size);
            return -1;
        }
        if (o.block_size < bpb.bps) {
            warnx("block size (%u) is too small; minimum is %u",
                o.block_size, bpb.bps);
            return -1;
        }
        if (o.block_size > bpb.bps * MAXSPC) {
            warnx("block size (%u) is too large; maximum is %u",
                o.block_size, bpb.bps * MAXSPC);
            return -1;
        }
        bpb.spc = o.block_size / bpb.bps;
    }
    if (o.sectors_per_cluster) {
        if (!powerof2(o.sectors_per_cluster)) {
            warnx("sectors/cluster (%u) is not a power of 2",
                o.sectors_per_cluster);
            return -1;
        }
        bpb.spc = o.sectors_per_cluster;
    }
    if (o.reserved_sectors)
        bpb.res = o.reserved_sectors;
    if (o.num_FAT) {
        if (o.num_FAT > MAXNFT) {
            warnx("number of FATs (%u) is too large; maximum is %u",
                 o.num_FAT, MAXNFT);
            return -1;
        }
        bpb.nft = o.num_FAT;
    }
    if (o.directory_entries)
        bpb.rde = o.directory_entries;
    if (o.media_descriptor_set) {
        if (o.media_descriptor < 0xf0) {
            warnx("illegal media descriptor (%#x)", o.media_descriptor);
            return -1;
        }
        bpb.mid = o.media_descriptor;
    }
    if (o.sectors_per_fat)
        bpb.bspf = o.sectors_per_fat;
    if (o.info_sector)
        bpb.infs = o.info_sector;
    if (o.backup_sector)
        bpb.bkbs = o.backup_sector;
    bss = 1;
    bname = NULL;
    fd1 = -1;
    if (o.bootstrap) {
        bname = o.bootstrap;
        if (!strchr(bname, '/')) {
            snprintf(buf, sizeof(buf), "/boot/%s", bname);
            if (!(bname = strdup(buf))) {
                warn(NULL);
                return -1;
            }
        }
        if ((fd1 = open(bname, O_RDONLY)) == -1 || fstat(fd1, &sb)) {
            warn("%s", bname);
            return -1;
        }
        if (!S_ISREG(sb.st_mode) || sb.st_size % bpb.bps ||
            sb.st_size < bpb.bps || sb.st_size > bpb.bps * MAXU16) {
            warnx("%s: inappropriate file type or format", bname);
            return -1;
        }
        bss = sb.st_size / bpb.bps;
    }
    if (!bpb.nft)
        bpb.nft = 2;
    if (!o.fat_type) {
        if (bpb.bsec < (bpb.res ? bpb.res : bss) +
            howmany((RESFTE + (bpb.spc ? MINCLS16 : MAXCLS12 + 1)) *
                    ((bpb.spc ? 16 : 12) / BPN), bpb.bps * NPB) *
            bpb.nft +
            howmany(bpb.rde ? bpb.rde : DEFRDE,
                    bpb.bps / sizeof(struct de)) +
            (bpb.spc ? MINCLS16 : MAXCLS12 + 1) *
            (bpb.spc ? bpb.spc : howmany(DEFBLK, bpb.bps)))
            o.fat_type = 12;
        else if (bpb.rde || bpb.bsec <
                 (bpb.res ? bpb.res : bss) +
                 howmany((RESFTE + MAXCLS16) * 2, bpb.bps) * bpb.nft +
                 howmany(DEFRDE, bpb.bps / sizeof(struct de)) +
                 (MAXCLS16 + 1) *
                 (bpb.spc ? bpb.spc : howmany(8192, bpb.bps)))
            o.fat_type = 16;
        else
            o.fat_type = 32;
    }
    x = bss;
    if (o.fat_type == 32) {
        if (!bpb.infs) {
            if (x == MAXU16 || x == bpb.bkbs) {
                warnx("no room for info sector");
                return -1;
            }
            bpb.infs = x;
        }
        if (bpb.infs != MAXU16 && x <= bpb.infs)
            x = bpb.infs + 1;
        if (!bpb.bkbs) {
            if (x == MAXU16) {
                warnx("no room for backup sector");
                return -1;
            }
            bpb.bkbs = x;
        } else if (bpb.bkbs != MAXU16 && bpb.bkbs == bpb.infs) {
            warnx("backup sector would overwrite info sector");
            return -1;
        }
        if (bpb.bkbs != MAXU16 && x <= bpb.bkbs)
            x = bpb.bkbs + 1;
    }
    if (!bpb.res)
        bpb.res = o.fat_type == 32 ? MAXIMUM(x, MAXIMUM(16384 / bpb.bps, 4)) : x;
    else if (bpb.res < x) {
        warnx("too few reserved sectors (need %d have %d)", x, bpb.res);
        return -1;
    }
    if (o.fat_type != 32 && !bpb.rde)
        bpb.rde = DEFRDE;
    rds = howmany(bpb.rde, bpb.bps / sizeof(struct de));
    if (!bpb.spc)
        for (bpb.spc = howmany(o.fat_type == 16 ? DEFBLK16 : DEFBLK, bpb.bps);
             bpb.spc < MAXSPC &&
             bpb.res +
             howmany((RESFTE + maxcls(o.fat_type)) * (o.fat_type / BPN),
                     bpb.bps * NPB) * bpb.nft +
             rds +
             (u_int64_t)(maxcls(o.fat_type) + 1) * bpb.spc <= bpb.bsec;
             bpb.spc <<= 1);
    if (o.fat_type != 32 && bpb.bspf > MAXU16) {
        warnx("too many sectors/FAT for FAT12/16");
        return -1;
    }
    x1 = bpb.res + rds;
    x = bpb.bspf ? bpb.bspf : 1;
    if (x1 + (u_int64_t)x * bpb.nft > bpb.bsec) {
        warnx("meta data exceeds file system size");
        return -1;
    }
    x1 += x * bpb.nft;
    x = (u_int64_t)(bpb.bsec - x1) * bpb.bps * NPB /
        (bpb.spc * bpb.bps * NPB + o.fat_type / BPN * bpb.nft);
    x2 = howmany((RESFTE + MINIMUM(x, maxcls(o.fat_type))) * (o.fat_type / BPN),
                 bpb.bps * NPB);
    if (!bpb.bspf) {
        bpb.bspf = x2;
        x1 += (bpb.bspf - 1) * bpb.nft;
    }
    cls = (bpb.bsec - x1) / bpb.spc;
    x = (u_int64_t)bpb.bspf * bpb.bps * NPB / (o.fat_type / BPN) - RESFTE;
    if (cls > x)
        cls = x;
    if (bpb.bspf < x2) {
        warnx("warning: sectors/FAT limits file system to %u clusters",
              cls);
        return -1;
    }
    if (cls < mincls(o.fat_type)) {
        warnx("%u clusters too few clusters for FAT%u, need %u", cls,
            o.fat_type, mincls(o.fat_type));
        return -1;
    }
    if (cls > maxcls(o.fat_type)) {
        cls = maxcls(o.fat_type);
        bpb.bsec = x1 + (cls + 1) * bpb.spc - 1;
        warnx("warning: FAT type limits file system to %u sectors",
              bpb.bsec);
        return -1;
    }
    printf("%s: %u sector%s in %u FAT%u cluster%s "
           "(%u bytes/cluster)\n", fname, cls * bpb.spc,
           cls * bpb.spc == 1 ? "" : "s", cls, o.fat_type,
           cls == 1 ? "" : "s", bpb.bps * bpb.spc);
    if (!bpb.mid)
        bpb.mid = !bpb.hid ? 0xf0 : 0xf8;
    if (o.fat_type == 32)
        bpb.rdcl = RESFTE;
    if (bpb.hid + bpb.bsec <= MAXU16) {
        bpb.sec = bpb.bsec;
        bpb.bsec = 0;
    }
    if (o.fat_type != 32) {
        bpb.spf = bpb.bspf;
        bpb.bspf = 0;
    }
    ch = 0;
    if (o.fat_type == 12)
        ch = 1;                 /* 001 Primary DOS with 12 bit FAT */
    else if (o.fat_type == 16) {
        if (bpb.bsec == 0)
            ch = 4;             /* 004 Primary DOS with 16 bit FAT <32M */
        else
            ch = 6;             /* 006 Primary 'big' DOS, 16-bit FAT (> 32MB) */
                                /*
                                 * XXX: what about:
                                 * 014 DOS (16-bit FAT) - LBA
                                 *  ?
                                 */
    } else if (o.fat_type == 32) {
        ch = 11;                /* 011 Primary DOS with 32 bit FAT */
                                /*
                                 * XXX: what about:
                                 * 012 Primary DOS with 32 bit FAT - LBA
                                 *  ?
                                 */
    }
    if (ch != 0)
        printf("MBR type: %d\n", ch);
    print_bpb(&bpb);

    gettimeofday(&tv, NULL);
    now = tv.tv_sec;
    tm = localtime(&now);
    img = emalloc(bpb.bps);
    dir = bpb.res + (bpb.spf ? bpb.spf : bpb.bspf) * bpb.nft;
    signal(SIGINFO, infohandler);
    for (lsn = 0; lsn < dir + (o.fat_type == 32 ? bpb.spc : rds); lsn++) {
        if (got_siginfo) {
            fprintf(stderr,"%s: writing sector %u of %u (%u%%)\n",
                fname,lsn,(dir + (o.fat_type == 32 ? bpb.spc : rds)),
                (lsn*100)/(dir + (o.fat_type == 32 ? bpb.spc : rds)));
            got_siginfo = 0;
        }
        x = lsn;
        if (o.bootstrap &&
            o.fat_type == 32 && bpb.bkbs != MAXU16 &&
            bss <= bpb.bkbs && x >= bpb.bkbs) {
            x -= bpb.bkbs;
            if (!x && lseek(fd1, o.offset, SEEK_SET)) {
                warn("%s", bname);
                return -1;
            }
        }
        if (o.bootstrap && x < bss) {
            if ((n = read(fd1, img, bpb.bps)) == -1) {
                warn("%s", bname);
                return -1;
            }
            if ((size_t)n != bpb.bps) {
                warnx("%s: can't read sector %u", bname, x);
                return -1;
            }
        } else
            memset(img, 0, bpb.bps);
        if (!lsn ||
          (o.fat_type == 32 && bpb.bkbs != MAXU16 && lsn == bpb.bkbs)) {
            x1 = sizeof(struct bs);
            bsbpb = (struct bsbpb *)(img + x1);
            mk2(bsbpb->bps, bpb.bps);
            mk1(bsbpb->spc, bpb.spc);
            mk2(bsbpb->res, bpb.res);
            mk1(bsbpb->nft, bpb.nft);
            mk2(bsbpb->rde, bpb.rde);
            mk2(bsbpb->sec, bpb.sec);
            mk1(bsbpb->mid, bpb.mid);
            mk2(bsbpb->spf, bpb.spf);
            mk2(bsbpb->spt, bpb.spt);
            mk2(bsbpb->hds, bpb.hds);
            mk4(bsbpb->hid, bpb.hid);
            mk4(bsbpb->bsec, bpb.bsec);
            x1 += sizeof(struct bsbpb);
            if (o.fat_type == 32) {
                bsxbpb = (struct bsxbpb *)(img + x1);
                mk4(bsxbpb->bspf, bpb.bspf);
                mk2(bsxbpb->xflg, 0);
                mk2(bsxbpb->vers, 0);
                mk4(bsxbpb->rdcl, bpb.rdcl);
                mk2(bsxbpb->infs, bpb.infs);
                mk2(bsxbpb->bkbs, bpb.bkbs);
                x1 += sizeof(struct bsxbpb);
            }
            bsx = (struct bsx *)(img + x1);
            mk1(bsx->sig, 0x29);
            if (o.volume_id_set)
                x = o.volume_id;
            else
                x = (((u_int)(1 + tm->tm_mon) << 8 |
                      (u_int)tm->tm_mday) +
                     ((u_int)tm->tm_sec << 8 |
                      (u_int)(tv.tv_usec / 10))) << 16 |
                    ((u_int)(1900 + tm->tm_year) +
                     ((u_int)tm->tm_hour << 8 |
                      (u_int)tm->tm_min));
            mk4(bsx->volid, x);
            mklabel(bsx->label, o.volume_label ? o.volume_label : "NO NAME");
            snprintf(buf, sizeof(buf), "FAT%u", o.fat_type);
            setstr(bsx->type, buf, sizeof(bsx->type));
            if (!o.bootstrap) {
                x1 += sizeof(struct bsx);
                bs = (struct bs *)img;
                mk1(bs->jmp[0], 0xeb);
                mk1(bs->jmp[1], x1 - 2);
                mk1(bs->jmp[2], 0x90);
                setstr(bs->oem, o.OEM_string ? o.OEM_string : "NetBSD",
                       sizeof(bs->oem));
                memcpy(img + x1, bootcode, sizeof(bootcode));
                mk2(img + MINBPS - 2, DOSMAGIC);
            }
        } else if (o.fat_type == 32 && bpb.infs != MAXU16 &&
                   (lsn == bpb.infs ||
                    (bpb.bkbs != MAXU16 &&
                     lsn == bpb.bkbs + bpb.infs))) {
            mk4(img, 0x41615252);
            mk4(img + MINBPS - 28, 0x61417272);
            mk4(img + MINBPS - 24, 0xffffffff);
            mk4(img + MINBPS - 20, 0xffffffff);
            mk2(img + MINBPS - 2, DOSMAGIC);
        } else if (lsn >= bpb.res && lsn < dir &&
                   !((lsn - bpb.res) %
                     (bpb.spf ? bpb.spf : bpb.bspf))) {
            mk1(img[0], bpb.mid);
            for (x = 1; x < o.fat_type * (o.fat_type == 32 ? 3U : 2U) / 8U; x++)
                mk1(img[x], o.fat_type == 32 && x % 4 == 3 ? 0x0f : 0xff);
        } else if (lsn == dir && o.volume_label) {
            de = (struct de *)img;
            mklabel(de->namext, o.volume_label);
            mk1(de->attr, 050);
            x = (u_int)tm->tm_hour << 11 |
                (u_int)tm->tm_min << 5 |
                (u_int)tm->tm_sec >> 1;
            mk2(de->time, x);
            x = (u_int)(tm->tm_year - 80) << 9 |
                (u_int)(tm->tm_mon + 1) << 5 |
                (u_int)tm->tm_mday;
            mk2(de->date, x);
        }
        if ((n = write(fd, img, bpb.bps)) == -1) {
            warn("%s", fname);
            return -1;
        }
        if ((size_t)n != bpb.bps) {
            warnx("%s: can't write sector %u", fname, lsn);
            return -1;
        }
    }
    return 0;
}


/*
 * Get a standard format.
 */
static int
getstdfmt(const char *fmt, struct bpb *bpb)
{
    u_int x, i;

    x = sizeof(stdfmt) / sizeof(stdfmt[0]);
    for (i = 0; i < x && strcmp(fmt, stdfmt[i].name); i++);
    if (i == x) {
        warnx("%s: unknown standard format", fmt);
        return -1;
    }
    *bpb = stdfmt[i].bpb;
    return 0;
}

/*
 * Get disk slice, partition, and geometry information.
 */
static int
getbpbinfo(int fd, const char *fname, const char *dtype, int iflag,
    struct bpb *bpb, int create)
{
    const char *s1, *s2;
    int part;

    part = -1;
    s1 = fname;
    if ((s2 = strrchr(s1, '/')))
        s1 = s2 + 1;
    for (s2 = s1; *s2 && !isdigit((unsigned char)*s2); s2++);
    if (!*s2 || s2 == s1)
        s2 = NULL;
    else
        while (isdigit((unsigned char)*++s2));
    s1 = s2;

    if (((part != -1) && ((!iflag && part != -1) || !bpb->bsec)) ||
        !bpb->bps || !bpb->spt || !bpb->hds) {
        u_int sector_size;
        u_int nsectors;
        u_int ntracks;
        u_int size;
        {
            struct stat st;

            if (fstat(fd, &st) == -1) {
                warnx("Can't get disk size for `%s'", fname);
                return -1;
            }
            /* create a fake geometry for a file image */
            sector_size = 512;
            nsectors = 63;
            ntracks = 255;
            size = st.st_size / sector_size;
        }
        if (!bpb->bps) {
            if (ckgeom(fname, sector_size, "bytes/sector") == -1)
                return -1;
            bpb->bps = sector_size;
        }

        if (nsectors > 63) {
                /*
                 * The kernel doesn't accept BPB with spt > 63.
                 * (see sys/fs/msdosfs/msdosfs_vfsops.c:msdosfs_mountfs())
                 * If values taken from disklabel don't match these
                 * restrictions, use popular BIOS default values instead.
                 */
                nsectors = 63;
        }
        if (!bpb->spt) {
            if (ckgeom(fname, nsectors, "sectors/track") == -1)
                return -1;
            bpb->spt = nsectors;
        }
        if (!bpb->hds) {
            if (ckgeom(fname, ntracks, "drive heads") == -1)
                return -1;
            bpb->hds = ntracks;
        }
        if (!bpb->bsec)
            bpb->bsec = size;
    }
    return 0;
}

/*
 * Print out BPB values.
 */
static void
print_bpb(struct bpb *bpb)
{
    printf("bps=%u spc=%u res=%u nft=%u", bpb->bps, bpb->spc, bpb->res,
           bpb->nft);
    if (bpb->rde)
        printf(" rde=%u", bpb->rde);
    if (bpb->sec)
        printf(" sec=%u", bpb->sec);
    printf(" mid=%#x", bpb->mid);
    if (bpb->spf)
        printf(" spf=%u", bpb->spf);
    printf(" spt=%u hds=%u hid=%u", bpb->spt, bpb->hds, bpb->hid);
    if (bpb->bsec)
        printf(" bsec=%u", bpb->bsec);
    if (!bpb->spf) {
        printf(" bspf=%u rdcl=%u", bpb->bspf, bpb->rdcl);
        printf(" infs=");
        printf(bpb->infs == MAXU16 ? "%#x" : "%u", bpb->infs);
        printf(" bkbs=");
        printf(bpb->bkbs == MAXU16 ? "%#x" : "%u", bpb->bkbs);
    }
    printf("\n");
}

/*
 * Check a disk geometry value.
 */
static int
ckgeom(const char *fname, u_int val, const char *msg)
{
    if (!val) {
        warnx("%s: no default %s", fname, msg);
        return -1;
    }
    if (val > MAXU16) {
        warnx("%s: illegal %s", fname, msg);
        return -1;
    }
    return 0;
}
/*
 * Check a volume label.
 */
static int
oklabel(const char *src)
{
    int c, i;

    for (i = 0; i <= 11; i++) {
        c = (u_char)*src++;
        if (c < ' ' + !i || strchr("\"*+,./:;<=>?[\\]|", c))
            break;
    }
    return i && !c;
}

/*
 * Make a volume label.
 */
static void
mklabel(u_int8_t *dest, const char *src)
{
    int c, i;

    for (i = 0; i < 11; i++) {
        c = *src ? toupper((unsigned char)*src++) : ' ';
        *dest++ = !i && c == '\xe5' ? 5 : c;
    }
}

/*
 * Copy string, padding with spaces.
 */
static void
setstr(u_int8_t *dest, const char *src, size_t len)
{
    while (len--)
        *dest++ = *src ? *src++ : ' ';
}

static void
infohandler(int sig)
{
    got_siginfo = 1;
}