/*      $NetBSD: fdisk.c,v 1.164 2025/12/30 21:33:34 nia Exp $ */

/*
 * Mach Operating System
 * Copyright (c) 1992 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */

/*
 * 14-Dec-89  Robert Baron (rvb) at Carnegie-Mellon University
 *      Copyright (c) 1989      Robert. V. Baron
 *      Created.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>

#ifndef lint
__RCSID("$NetBSD: fdisk.c,v 1.164 2025/12/30 21:33:34 nia Exp $");
#endif /* not lint */

#define MBRPTYPENAMES
#include <sys/types.h>
#include <sys/param.h>
#if defined(HAVE_SYS_ENDIAN_H) || ! defined(HAVE_NBTOOL_CONFIG_H)
#include <sys/endian.h>
#endif
#include <sys/stat.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <vis.h>
#include <zlib.h>

#if !HAVE_NBTOOL_CONFIG_H
#include <sys/disklabel.h>
#include <sys/disklabel_gpt.h>
#include <sys/bootblock.h>
#include <sys/ioctl.h>
#include <sys/sysctl.h>
#include <disktab.h>
#include <util.h>
#else
#include <nbinclude/sys/disklabel.h>
#include <nbinclude/sys/disklabel_gpt.h>
#include <nbinclude/sys/bootblock.h>
#include "../../include/disktab.h"
/* We enforce -F, so none of these possibly undefined items can be needed */
#define opendisk(path, fl, buf, buflen, cooked) (-1)
#endif /* HAVE_NBTOOL_CONFIG_H */

#ifndef DEFAULT_BOOTDIR
#define DEFAULT_BOOTDIR         "/usr/mdec"
#endif

#define LE_MBR_MAGIC            htole16(MBR_MAGIC)
#define LE_MBR_BS_MAGIC         htole16(MBR_BS_MAGIC)

#ifdef BOOTSEL

#define DEFAULT_BOOTCODE        "mbr"
#define DEFAULT_BOOTSELCODE     "mbr_bootsel"
#define DEFAULT_BOOTEXTCODE     "mbr_ext"

/* Scan values for the various keys we use, as returned by the BIOS */
#define SCAN_ENTER      0x1c
#define SCAN_F1         0x3b
#define SCAN_1          0x2


#define MAX_BIOS_DISKS  16      /* Going beyond F12 is hard though! */

/* We same the dflt 'boot partition' as a disk block, with some magic values. */
#define DEFAULT_ACTIVE  (~(daddr_t)0)
#define DEFAULT_DISK(n) (DEFAULT_ACTIVE - MAX_BIOS_DISKS + (n))

#endif

#define GPT_TYPE(offs) ((offs) == GPT_HDR_BLKNO ?  "primary" : "secondary")

#ifndef PRIdaddr
#define PRIdaddr PRId64
#endif

#ifndef _PATH_DEFDISK
#define _PATH_DEFDISK   "/dev/rwd0d"
#endif

static struct {
        struct mbr_sector *ptn;         /* array of pbrs */
        daddr_t         base;           /* first sector of ext. ptn */
        daddr_t         limit;          /* last sector of ext. ptn */
        int             num_ptn;        /* number of contained partitions */
        int             ptn_id;         /* entry in mbr */
        int             is_corrupt;     /* 1 if extended chain illegal */
} ext;

#define LBUF 100
static char lbuf[LBUF];

static const char *disk = _PATH_DEFDISK;

static struct disklabel disklabel;              /* disk parameters */

static struct mbr_sector mboot;

static const char *boot_dir = DEFAULT_BOOTDIR;
static char *boot_path = NULL;                  /* name of file we actually opened */

#ifdef BOOTSEL
#define BOOTSEL_OPTIONS "B"
#else
#define BOOTSEL_OPTIONS ""
#define change_part(e, p, id, st, sz, bm) change__part(e, p, id, st, sz)
#endif
#define OPTIONS BOOTSEL_OPTIONS "0123FSafgiIluvA:b:c:E:r:s:w:z:"

/*
 * Disk geometry and partition alignment.
 *
 * Modern disks do not have a fixed geomery and will always give a 'faked'
 * geometry that matches the ATA standard - max 16 heads and 256 sec/track.
 * The ATA geometry allows access to 2^28 sectors (as does LBA mode).
 *
 * The BIOS calls originally used an 8bit register for cylinder, head and
 * sector. Later 2 bits were stolen from the sector number and added to
 * cylinder number. The BIOS will translate this faked geometry either to
 * the geometry reported by the disk, or do LBA reads (possibly LBA48).
 * BIOS CHS reads have all sorts of limits, but 2^24 is absolute.
 * For historic reasons the BIOS geometry is the called the dos geometry!
 *
 * If you know the disks real geometry it is usually worth aligning
 * disk partitions to cylinder boundaries (certainly traditional!).
 * For 'mbr' disks this has always been done with the BIOS geometry.
 * The first track (typically 63 sectors) is reserved because the first
 * sector is used for boot code. Similarly the data partition in an
 * extended partition will start one track in. If an extended partition
 * starts at the beginning of the disk you lose 2 tracks.
 *
 * However non-magnetic media in particular has physical sectors that are
 * not the same size as those reported, so has to do read modify write
 * sequences for misaligned transfers. The alignment of partitions to
 * cylinder boundaries makes this happen all the time.
 *
 * It is thus sensible to align partitions on a sensible sector boundary.
 * For instance 1MB (2048 sectors).
 * Common code can do this by using a geometry with 1 head and 2048
 * sectors per track.
 */

/* Disks reported geometry and overall size from device driver */
static unsigned int cylinders, sectors, heads;
static daddr_t disksectors;
#define cylindersectors (heads * sectors)

/* Geometry from the BIOS */
static unsigned int dos_cylinders;
static unsigned int dos_heads;
static unsigned int dos_sectors;
static daddr_t dos_disksectors;
#define dos_cylindersectors (dos_heads * dos_sectors)
#define dos_totalsectors (dos_heads * dos_sectors * dos_cylinders)

#define DOSSECT(s,c)    (((s) & 0x3f) | (((c) >> 2) & 0xc0))
#define DOSCYL(c)       ((c) & 0xff)
#define SEC_IN_1M (1024 * 1024 / secsize)
#define SEC_TO_MB(sec) ((unsigned int)(((sec) + SEC_IN_1M / 2) / SEC_IN_1M))
#define SEC_TO_CYL(sec) (((sec) + dos_cylindersectors/2) / dos_cylindersectors)

#define MAXCYL          1024    /* Usual limit is 1023 */
#define MAXHEAD         256     /* Usual limit is 255 */
#define MAXSECTOR       63
static int partition = -1;

/* Alignment of partition, and offset if first sector unusable */
static unsigned int ptn_alignment;      /* default dos_cylindersectors */
static unsigned int ptn_0_offset;       /* default dos_sectors */

static int fd = -1, wfd = -1, *rfd = &fd;
static char *disk_file = NULL;

static int a_flag;              /* set active partition */
static int i_flag;              /* init bootcode */
static int I_flag;              /* ignore errors */
static int u_flag;              /* update partition data */
static int v_flag;              /* more verbose */
static int sh_flag;             /* Output data as shell defines */
static int f_flag;              /* force --not interactive */
static int g_flag;              /* preserve GPT headers */
static int s_flag;              /* set id,offset,size */
static int b_flag;              /* Set cyl, heads, secs (as c/h/s) */
static int B_flag;              /* Edit/install bootselect code */
static int E_flag;              /* extended partition number */
static int b_cyl, b_head, b_sec;  /* b_flag values. */

#if !HAVE_NBTOOL_CONFIG_H
static int F_flag = 0;
#else
/* Tool - force 'file' mode to avoid unsupported functions and ioctls */
static int F_flag = 1;
#endif

static struct gpt_hdr gpt1, gpt2;       /* GUID partition tables */

static struct mbr_sector bootcode[8192 / sizeof (struct mbr_sector)];
static ssize_t secsize = 512;   /* sector size */
static char *iobuf;             /* buffer for non 512 sector I/O */
static int bootsize;            /* actual size of bootcode */
static int boot_installed;      /* 1 if we've copied code into the mbr */

#if defined(USE_DISKLIST)
#include <machine/cpu.h>
static struct disklist *dl;
#endif


#define KNOWN_SYSIDS    (sizeof(mbr_ptypes)/sizeof(mbr_ptypes[0]))

__dead static void      usage(void);
static void     print_s0(int);
static void     print_part(struct mbr_sector *, int, daddr_t);
static void     print_mbr_partition(struct mbr_sector *, int, daddr_t, daddr_t, int);
static void     print_pbr(daddr_t, int, uint8_t);
static int      is_all_zero(const unsigned char *, size_t);
static void     printvis(int, const char *, const char *, size_t);
static int      read_boot(const char *, void *, size_t, int);
static void     init_sector0(int);
static void     intuit_translated_geometry(void);
static void     get_bios_geometry(void);
static void     get_extended_ptn(void);
static void     get_ptn_alignmemt(void);
#if defined(USE_DISKLIST)
static void     get_diskname(const char *, char *, size_t);
#endif
static int      change_part(int, int, int, daddr_t, daddr_t, char *);
static void     print_geometry(void);
static int      first_active(void);
static void     change_active(int);
static void     change_bios_geometry(void);
static void     dos(int, unsigned char *, unsigned char *, unsigned char *);
static int      open_disk(int);
static ssize_t  read_disk(daddr_t, void *);
static ssize_t  write_disk(daddr_t, void *);
static int      get_params(void);
static int      read_s0(daddr_t, struct mbr_sector *);
static int      write_mbr(void);
static int      read_gpt(daddr_t, struct gpt_hdr *);
static int      delete_gpt(struct gpt_hdr *);
static int      yesno(const char *, ...) __printflike(1, 2);
static int64_t  decimal(const char *, int64_t, int, int64_t, int64_t);
#define DEC_SEC         1               /* asking for a sector number */
#define DEC_RND         2               /* round to end of first track */
#define DEC_RND_0       4               /* convert 0 to size of a track */
#define DEC_RND_DOWN    8               /* subtract 1 track */
#define DEC_RND_DOWN_2  16              /* subtract 2 tracks */
static int      ptn_id(const char *, int *);
static int      type_match(const void *, const void *);
static const char *get_type(int);
static int      get_mapping(int, unsigned int *, unsigned int *, unsigned int *, unsigned long *);
#ifdef BOOTSEL
static daddr_t  configure_bootsel(daddr_t);
static void     install_bootsel(int);
static daddr_t  get_default_boot(void);
static void     set_default_boot(daddr_t);
static void     string(const char *, int, char *);
#endif

static void
initvar_disk(const char **diskp)
{
#if !HAVE_NBTOOL_CONFIG_H
        int mib[2];
        size_t len;
        char *root_device;

        mib[0] = CTL_KERN;
        mib[1] = KERN_ROOT_DEVICE;
        if (sysctl(mib, 2, NULL, &len, NULL, 0) == -1 ||
            (root_device = malloc(len)) == NULL ||
            sysctl(mib, 2, root_device, &len, NULL, 0) == -1)
                return;

        *diskp = root_device;
#endif /* HAVE_NBTOOL_CONFIG_H */
}

static int
getnum(const char *str, int *num)
{
        char *e;
        long l;

        errno = 0;
        l = strtol(str, &e, 0);
        if (str[0] == '\0' || *e != '\0')
                return -1;
        if (errno == ERANGE && (l == LONG_MAX || l == LONG_MIN))
                return -1;
        /* XXX: truncation */
        *num = (int)l;
        return 0;
}

/* [<sysid>][/[<start>][/[<size>][/[<bootmenu>]]]] */
static int
parse_s(char *arg, int *csysid, unsigned *cstart, unsigned *csize,
    char **cbootmenu)
{
        char *ptr;
        int num;

        if ((ptr = strchr(arg, '/')) != NULL)
                *ptr++ = '\0';

        if (*arg) {
                if (getnum(arg, &num) == -1)
                        return -1;
                *csysid = num;
        }
        if (ptr == NULL)
                return 0;

        arg = ptr;
        if ((ptr = strchr(arg, '/')) != NULL)
                *ptr++ = '\0';
        if (*arg) {
                if (getnum(arg, &num) == -1)
                        return -1;
                *cstart = num;
        }
        if (ptr == NULL)
                return 0;

        arg = ptr;
        if ((ptr = strchr(arg, '/')) != NULL)
                *ptr++ = '\0';
        if (*arg) {
                if (getnum(arg, &num) == -1)
                        return -1;
                *csize = num;
        }
        if (ptr != NULL && *ptr)
                *cbootmenu = ptr;
        return 0;
}

int
main(int argc, char *argv[])
{
        struct stat sb;
        int ch;
        size_t len;
        char *cp;
        int n;
#ifdef BOOTSEL
        daddr_t default_ptn;            /* start sector of default ptn */
#endif
        char *cbootmenu = 0;

        int csysid;     /* For the s_flag. */
        unsigned int cstart, csize;
        a_flag = u_flag = sh_flag = f_flag = s_flag = b_flag = 0;
        i_flag = B_flag = 0;
        v_flag = 0;
        E_flag = 0;
        csysid = -1;
        cstart = csize = ~0U;
        while ((ch = getopt(argc, argv, OPTIONS)) != -1) {
                switch (ch) {
                case '0':
                        partition = 0;
                        break;
                case '1':
                        partition = 1;
                        break;
                case '2':
                        partition = 2;
                        break;
                case '3':
                        partition = 3;
                        break;
                case 'E':       /* Extended partition number */
                        E_flag = 1;
                        unsigned long ul = strtoul(optarg, &cp, 0);
                        if (*cp || ul > INT_MAX)
                                errx(1, "Bad partition number -E %s.", optarg);
                        partition = (int)ul;
                        break;
#ifdef BOOTSEL
                case 'B':       /* Bootselect parameters */
                        B_flag = 1;
                        break;
#endif
                case 'F':       /* device argument is really a file */
                        F_flag = 1;
                        break;
                case 'S':       /* Output as shell variables */
                        sh_flag = 1;
                        break;
                case 'a':       /* Set active partition */
                        a_flag = 1;
                        break;
                case 'f':       /* Non interactive */
                        f_flag = 1;
                        break;
                case 'g':       /* Preserve GPT headers */
                        g_flag = 1;
                        break;
                case 'i':       /* Always update bootcode */
                        i_flag = 1;
                        break;
                case 'I':       /* Ignore errors */
                        I_flag = 1;
                        break;
                case 'l':       /* List known partition types */
                        for (len = 0; len < KNOWN_SYSIDS; len++)
                                printf("%03d %s\n", mbr_ptypes[len].id,
                                    mbr_ptypes[len].name);
                        return 0;
                case 'u':       /* Update partition details */
                        u_flag = 1;
                        break;
                case 'v':       /* Be verbose */
                        v_flag++;
                        break;
                case 's':       /* Partition details */
                        s_flag = 1;

                        if (parse_s(optarg, &csysid, &cstart, &csize,
                            &cbootmenu) == -1)
                                errx(1, "Bad argument to the -s flag.");
                        break;
                case 'b':       /* BIOS geometry */
                        b_flag = 1;
                        if (sscanf(optarg, "%d/%d/%d%n", &b_cyl, &b_head,
                            &b_sec, &n) != 3 || optarg[n] != 0)
                                errx(1, "Bad argument to the -b flag.");
                        if (b_cyl > MAXCYL)
                                b_cyl = MAXCYL;
                        break;
                case 'A':       /* Partition alignment[/offset] */
                        if (sscanf(optarg, "%u%n/%u%n", &ptn_alignment,
                                    &n, &ptn_0_offset, &n) < 1
                            || optarg[n] != 0
                            || ptn_0_offset > ptn_alignment)
                                errx(1, "Bad argument to the -A flag.");
                        if (ptn_0_offset == 0)
                                ptn_0_offset = ptn_alignment;
                        break;
                case 'c':       /* file/directory containing boot code */
                        if (strchr(optarg, '/') != NULL &&
                            stat(optarg, &sb) == 0 &&
                            (sb.st_mode & S_IFMT) == S_IFDIR) {
                                boot_dir = optarg;
                                break;
                        }
                        bootsize = read_boot(optarg, bootcode,
                                                sizeof bootcode, 1);
                        i_flag = 1;
                        break;
                case 'r':       /* read data from disk_file (not raw disk) */
                        rfd = &wfd;
                        /* FALLTHROUGH */
                case 'w':       /* write data to disk_file */
                        disk_file = optarg;
                        break;
                case 'z':
                        secsize = atoi(optarg);
                        if (secsize <= 512 || (secsize & (secsize - 1)) != 0)
                                errx(EXIT_FAILURE, "Invalid sector size %zd",
                                    secsize);
                        break;
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        if (sh_flag && (a_flag || i_flag || u_flag || f_flag || s_flag))
                usage();

        if (B_flag && f_flag) {
                warnx("Bootselector may only be configured interactively");
                usage();
        }

        if (f_flag && u_flag && !s_flag) {
                warnx("Partition data not specified");
                usage();
        }

        if (s_flag && partition == -1) {
                warnx("-s flag requires a partition selected.");
                usage();
        }

        if (argc > 1)
                usage();

        if (argc > 0)
                disk = argv[0];
        else if (!F_flag) {
                /* Default to boot device */
                initvar_disk(&disk);
        }

        if (!F_flag && stat(disk, &sb) == 0 && S_ISREG(sb.st_mode))
                F_flag = 1;

        if (open_disk(B_flag || a_flag || i_flag || u_flag) < 0)
                exit(1);

        if (secsize > 512) {
                if ((iobuf = malloc(secsize)) == NULL)
                        err(EXIT_FAILURE, "Cannot allocate %zd buffer",
                            secsize);
        }

        if (read_s0(0, &mboot))
                /* must have been a blank disk */
                init_sector0(1);

        read_gpt(GPT_HDR_BLKNO, &gpt1);
        read_gpt(disksectors - 1, &gpt2);

        if (b_flag) {
                dos_cylinders = b_cyl;
                dos_heads = b_head;
                dos_sectors = b_sec;
        } else {
                get_bios_geometry();
        }

        if (ptn_alignment == 0)
                get_ptn_alignmemt();

        get_extended_ptn();

#ifdef BOOTSEL
        default_ptn = get_default_boot();
#endif

        if (E_flag && !u_flag && partition >= ext.num_ptn)
                errx(1, "Extended partition %d is not defined.", partition);

        /* Do the update stuff! */
        if (u_flag) {
                if (!f_flag && !b_flag)
                        change_bios_geometry();

                if (s_flag)
                        change_part(E_flag, partition, csysid, cstart, csize,
                                cbootmenu);
                else {
                        int part = partition, chg_ext = E_flag, prompt = 1;
                        do {
                                if (prompt) {
                                        printf("\n");
                                        print_s0(partition);
                                }
                                if (partition == -1)
                                        part = ptn_id(
                                    "Which partition do you want to change?",
                                                        &chg_ext);
                                if (part < 0)
                                        break;
                                prompt = change_part(chg_ext, part, 0, 0, 0, 0);
                        } while (partition == -1);
                }
        } else {
                if (!i_flag && !B_flag) {
                        print_geometry();
                        print_s0(partition);
                }
        }

        if (a_flag && !E_flag)
                change_active(partition);

#ifdef BOOTSEL
        if (B_flag || u_flag || i_flag)
                /* Ensure the mbr code supports this configuration */
                install_bootsel(0);
        if (B_flag)
                default_ptn = configure_bootsel(default_ptn);
        set_default_boot(default_ptn);
#else
        if (i_flag)
                init_sector0(0);
#endif

        if (u_flag || a_flag || i_flag || B_flag) {
                if (!f_flag) {
                        printf("\nWe haven't written the MBR back to disk "
                               "yet.  This is your last chance.\n");
                        if (u_flag)
                                print_s0(-1);
                        if (gpt1.hdr_size != 0 || gpt2.hdr_size != 0)
                                printf("\nWARNING: The disk is carrying "
                                       "GUID Partition Tables.\n"
                                       "         If you continue, "
                                       "GPT headers will be deleted.\n\n");
                        if (yesno("Should we write new partition table?")) {
                                delete_gpt(&gpt1);
                                delete_gpt(&gpt2);
                                write_mbr();
                        }
                } else {
                        if (delete_gpt(&gpt1) > 0)
                                warnx("Primary GPT header was deleted");
                        if (delete_gpt(&gpt2) > 0)
                                warnx("Secondary GPT header was deleted");
                        write_mbr();
                }
        }

        exit(0);
}

static void
usage(void)
{
        int indent = 7 + (int)strlen(getprogname()) + 1;

        (void)fprintf(stderr, "usage: %s [-aBFfgIilSuv] "
                "[-A ptn_alignment[/ptn_0_offset]] \\\n"
                "%*s[-b cylinders/heads/sectors] \\\n"
                "%*s[-0123 | -E num "
                "[-s [id][/[start][/[size][/bootmenu]]]] \\\n"
                "%*s[-t disktab] [-T disktype] \\\n"
                "%*s[-c bootcode] "
                "[-r|-w file] [-z sectorsize] [device]\n"
                "\t-a change active partition\n"
                "\t-f force - not interactive\n"
                "\t-g preserve existing GPT headers\n"
                "\t-i initialise MBR code\n"
                "\t-I ignore errors about no space or overlapping partitions\n"
                "\t-l list partition types\n"
                "\t-u update partition data\n"
                "\t-v verbose output, -v -v more verbose still\n"
                "\t-B update bootselect options\n"
                "\t-F treat device as a regular file\n"
                "\t-S output as shell defines\n"
                "\t-r and -w access 'file' for non-destructive testing\n",
                getprogname(), indent, "", indent, "", indent, "", indent, "");
        exit(1);
}

static daddr_t
ext_offset(int part)
{
        daddr_t offset = ext.base;

        if (part != 0)
                offset += le32toh(ext.ptn[part - 1].mbr_parts[1].mbrp_start);
        return offset;
}

static void
print_s0(int which)
{
        int part;

        if (which == -1) {
                if (!sh_flag)
                        printf("Partition table:\n");
                for (part = 0; part < MBR_PART_COUNT; part++) {
                        if (!sh_flag)
                                printf("%d: ", part);
                        print_part(&mboot, part, 0);
                }
                if (!sh_flag) {
                        if (ext.is_corrupt)
                                printf("Extended partition table is corrupt\n");
                        else
                                if (ext.num_ptn != 0)
                                        printf("Extended partition table:\n");
                }
                for (part = 0; part < ext.num_ptn; part++) {
                        if (!sh_flag)
                                printf("E%d: ", part);
                        print_part(&ext.ptn[part], 0, ext_offset(part));
                        if (!sh_flag && v_flag >= 2) {
                                printf("link: ");
                                print_mbr_partition(&ext.ptn[part], 1,
                                                ext_offset(part), ext.base, 0);
                        }
                }
#ifdef BOOTSEL
                if (!sh_flag && mboot.mbr_bootsel_magic == LE_MBR_BS_MAGIC) {
                        int tmo;

                        printf("Bootselector ");
                        if (mboot.mbr_bootsel.mbrbs_flags & MBR_BS_ACTIVE) {
                                printf("enabled");
                                tmo = le16toh(mboot.mbr_bootsel.mbrbs_timeo);
                                if (tmo == 0xffff)
                                        printf(", infinite timeout");
                                else
                                        printf(", timeout %d seconds",
                                                    (10 * tmo + 9) / 182);
                        } else
                                printf("disabled");
                        printf(".\n");
                }
#endif
                if (!sh_flag) {
                        int active = first_active();
                        if (active == MBR_PART_COUNT)
                                printf("No active partition.\n");
                        else
                                printf("First active partition: %d\n", active);
                }
                if (!sh_flag)
                        printf("Drive serial number: %"PRIu32" (0x%08x)\n",
                            le32toh(mboot.mbr_dsn),
                            le32toh(mboot.mbr_dsn));
                return;
        }

        if (E_flag) {
                if (!sh_flag)
                        printf("Extended partition E%d:\n", which);
                if (which > ext.num_ptn)
                        printf("Undefined\n");
                else
                        print_part(&ext.ptn[which], 0, ext_offset(which));
        } else {
                if (!sh_flag)
                        printf("Partition %d:\n", which);
                print_part(&mboot, which, 0);
        }
}

static void
print_part(struct mbr_sector *boot, int part, daddr_t offset)
{
        struct mbr_partition *partp;
        const char *e;

        if (!sh_flag) {
                print_mbr_partition(boot, part, offset, 0, 0);
                return;
        }

        partp = &boot->mbr_parts[part];
        if (boot != &mboot) {
                part = boot - ext.ptn;
                e = "E";
        } else
                e = "";

        if (partp->mbrp_type == 0) {
                printf("PART%s%dSIZE=0\n", e, part);
                return;
        }

        printf("PART%s%dID=%d\n", e, part, partp->mbrp_type);
        printf("PART%s%dSIZE=%u\n", e, part, le32toh(partp->mbrp_size));
        printf("PART%s%dSTART=%"PRIdaddr"\n", e, part,
            offset + le32toh(partp->mbrp_start));
        printf("PART%s%dFLAG=0x%x\n", e, part, partp->mbrp_flag);
        printf("PART%s%dBCYL=%d\n", e, part,
            MBR_PCYL(partp->mbrp_scyl, partp->mbrp_ssect));
        printf("PART%s%dBHEAD=%d\n", e, part, partp->mbrp_shd);
        printf("PART%s%dBSEC=%d\n", e, part, MBR_PSECT(partp->mbrp_ssect));
        printf("PART%s%dECYL=%d\n", e, part,
            MBR_PCYL(partp->mbrp_ecyl, partp->mbrp_esect));
        printf("PART%s%dEHEAD=%d\n", e, part, partp->mbrp_ehd);
        printf("PART%s%dESEC=%d\n", e, part, MBR_PSECT(partp->mbrp_esect));
}

static void
pr_cyls(daddr_t sector, int is_end)
{
        unsigned long cyl, head, sect;
        cyl = sector / dos_cylindersectors;
        sect = sector - cyl * dos_cylindersectors;
        head = sect / dos_sectors;
        sect -= head * dos_sectors;

        printf("%lu", cyl);

        if (is_end) {
                if (head == dos_heads - 1 && sect == dos_sectors - 1)
                        return;
        } else {
                if (head == 0 && sect == 0)
                        return;
        }

        printf("/%lu/%lu", head, sect + 1);
}

static void
print_mbr_partition(struct mbr_sector *boot, int part,
    daddr_t offset, daddr_t exoffset, int indent)
{
        daddr_t start;
        daddr_t size;
        struct mbr_partition *partp = &boot->mbr_parts[part];
        struct mbr_sector eboot;
        int p;
        static int dumped = 0;

        if (partp->mbrp_type == 0 && v_flag < 2) {
                printf("<UNUSED>\n");
                return;
        }

        start = le32toh(partp->mbrp_start);
        size = le32toh(partp->mbrp_size);
        if (MBR_IS_EXTENDED(partp->mbrp_type))
                start += exoffset;
        else
                start += offset;

        printf("%s (sysid %d)\n", get_type(partp->mbrp_type), partp->mbrp_type);
#ifdef BOOTSEL
        if (boot->mbr_bootsel_magic == LE_MBR_BS_MAGIC &&
            boot->mbr_bootsel.mbrbs_nametab[part][0])
                printf("%*s    bootmenu: %s\n", indent, "",
                    boot->mbr_bootsel.mbrbs_nametab[part]);
#endif

        printf("%*s    start %"PRIdaddr", size %"PRIdaddr,
            indent, "", start, size);
        if (size != 0) {
                printf(" (%u MB, Cyls ", SEC_TO_MB(size));
                if (v_flag == 0 && le32toh(partp->mbrp_start) == ptn_0_offset)
                        pr_cyls(start - ptn_0_offset, 0);
                else
                        pr_cyls(start, 0);
                printf("-");
                pr_cyls(start + size - 1, 1);
                printf(")");
        }

        switch (partp->mbrp_flag) {
        case 0:
                break;
        case MBR_PFLAG_ACTIVE:
                printf(", Active");
                break;
        default:
                printf(", flag 0x%x", partp->mbrp_flag);
                break;
        }
        printf("\n");

        if (v_flag) {
                printf("%*s        beg: cylinder %4d, head %3d, sector %2d\n",
                    indent, "",
                    MBR_PCYL(partp->mbrp_scyl, partp->mbrp_ssect),
                    partp->mbrp_shd, MBR_PSECT(partp->mbrp_ssect));
                printf("%*s        end: cylinder %4d, head %3d, sector %2d\n",
                    indent, "",
                    MBR_PCYL(partp->mbrp_ecyl, partp->mbrp_esect),
                    partp->mbrp_ehd, MBR_PSECT(partp->mbrp_esect));
        }

        if (partp->mbrp_type == 0 && start == 0 && v_flag < 3)
                return;

        if (! MBR_IS_EXTENDED(partp->mbrp_type))
                print_pbr(start, indent + 8, partp->mbrp_type);

        if (!MBR_IS_EXTENDED(partp->mbrp_type) ||
            (v_flag <= 2 && !ext.is_corrupt))
                return;

        /*
         * Recursive dump extended table,
         * This is read from the disk - so is wrong during editing.
         * Just ensure we only show it once.
         */
        if (dumped)
                return;

        printf("%*s    Extended partition table:\n", indent, "");
        indent += 4;
        if (read_s0(start, &eboot) == -1)
                return;
        for (p = 0; p < MBR_PART_COUNT; p++) {
                printf("%*s%d: ", indent, "", p);
                print_mbr_partition(&eboot, p, start,
                                    exoffset ? exoffset : start, indent);
        }

        if (exoffset == 0)
                dumped = 1;
}

/* Print a line with a label and a vis-encoded string */
static void
printvis(int indent, const char *label, const char *buf, size_t size)
{
        char *visbuf;

        if ((visbuf = malloc(size * 4 + 1)) == NULL)
                err(1, "Malloc failed");
        strsvisx(visbuf, buf, size, VIS_TAB|VIS_NL|VIS_OCTAL, "\"");
        printf("%*s%s: \"%s\"\n",
            indent, "",
            label, visbuf);
        free(visbuf);
}

/* Check whether a buffer contains all bytes zero */
static int
is_all_zero(const unsigned char *p, size_t size)
{

        while (size-- > 0) {
                if (*p++ != 0)
                        return 0;
        }
        return 1;
}

/*
 * Report on the contents of a PBR sector.
 *
 * We first perform several sanity checks.  If vflag >= 2, we report all
 * failing tests, but for smaller values of v_flag we stop after the
 * first failing test.  Tests are ordered in an attempt to get the most
 * useful error message from the first failing test.
 *
 * If v_flag >= 2, we also report some decoded values from the PBR.
 * These results may be meaningless, if the PBR doesn't follow common
 * conventions.
 *
 * Trying to decode anything more than the magic number in the last
 * two bytes is a layering violation, but it can be very useful in
 * diagnosing boot failures.
 */
static void
print_pbr(daddr_t sector, int indent, uint8_t part_type __unused)
{
        struct mbr_sector pboot;
        unsigned char *p, *endp;
        unsigned char val;
        int ok;
        int errcount = 0;

#define PBR_ERROR(...)                                                  \
        do {                                                            \
                ++errcount;                                             \
                printf("%*s%s: ", indent, "",                           \
                    (v_flag < 2 ? "PBR is not bootable" : "Not bootable")); \
                printf(__VA_ARGS__);                                    \
                if (v_flag < 2)                                         \
                        return;                                         \
        } while (/*CONSTCOND*/ 0)

        if (v_flag >= 2) {
                printf("%*sInformation from PBR:\n",
                    indent, "");
                indent += 4;
        }

        if (read_disk(sector, &pboot) == -1) {
                PBR_ERROR("Sector %"PRIdaddr" is unreadable (%s)\n",
                    sector, strerror(errno));
                return;
        }

        /* all bytes identical? */
        p = (unsigned char *)&pboot;
        endp = p + sizeof(pboot);
        val = *p;
        ok = 0;
        for (; p < endp; p++) {
                if (*p != val) {
                        ok = 1;
                        break;
                }
        }
        if (! ok)
                PBR_ERROR("All bytes are identical (0x%02x)\n", val);

        if (pboot.mbr_magic != LE_MBR_MAGIC)
                PBR_ERROR("Bad magic number (0x%04x)\n",
                        le16toh(pboot.mbr_magic));

#if 0
        /* Some i386 OS might fail this test.  All non-i386 will fail. */
        if (pboot.mbr_jmpboot[0] != 0xE9
            && pboot.mbr_jmpboot[0] != 0xEB) {
                PBR_ERROR("Does not begin with i386 JMP instruction"
                        " (0x%02x 0x%02x0 0x%02x)\n",
                    pboot.mbr_jmpboot[0], pboot.mbr_jmpboot[1],
                    pboot.mbr_jmpboot[2]);
        }
#endif

        if (v_flag > 0 && errcount == 0)
                printf("%*sPBR appears to be bootable\n",
                    indent, "");
        if (v_flag < 2)
                return;

        if (! is_all_zero(pboot.mbr_oemname, sizeof(pboot.mbr_oemname))) {
                printvis(indent, "OEM name", (char *)pboot.mbr_oemname,
                        sizeof(pboot.mbr_oemname));
        }

        if (pboot.mbr_bpb.bpb16.bsBootSig == 0x29)
                printf("%*sBPB FAT16 boot signature found\n",
                    indent, "");
        if (pboot.mbr_bpb.bpb32.bsBootSig == 0x29)
                printf("%*sBPB FAT32 boot signature found\n",
                    indent, "");

#undef PBR_ERROR
}

static int
read_boot(const char *name, void *buf, size_t len, int err_exit)
{
        int bfd, ret;
        struct stat st;

        if (boot_path != NULL)
                free(boot_path);
        if (strchr(name, '/') == 0)
                asprintf(&boot_path, "%s/%s", boot_dir, name);
        else
                boot_path = strdup(name);
        if (boot_path == NULL)
                err(1, "Malloc failed");

        if ((bfd = open(boot_path, O_RDONLY)) < 0 || fstat(bfd, &st) == -1) {
                warn("%s", boot_path);
                goto fail;
        }

        if (st.st_size > (off_t)len) {
                warnx("%s: bootcode too large", boot_path);
                goto fail;
        }
        ret = st.st_size;
        if (ret < 0x200) {
                warnx("%s: bootcode too small", boot_path);
                goto fail;
        }
        if (read(bfd, buf, len) != ret) {
                warn("%s", boot_path);
                goto fail;
        }

        if (((struct mbr_sector *)buf)->mbr_magic != LE_MBR_MAGIC) {
                warnx("%s: invalid magic", boot_path);
                goto fail;
        }

        close(bfd);
        ret = (ret + 0x1ff) & ~0x1ff;
        return ret;

    fail:
        if (bfd >= 0)
                close(bfd);
        if (err_exit)
                exit(1);
        return 0;
}

static void
init_sector0(int zappart)
{
        int i;
        int copy_size = offsetof(struct mbr_sector, mbr_dsn);

#ifdef DEFAULT_BOOTCODE
        if (bootsize == 0)
                bootsize = read_boot(DEFAULT_BOOTCODE, bootcode,
                        sizeof bootcode, 0);
#endif
#ifdef BOOTSEL
        if (mboot.mbr_bootsel_magic == LE_MBR_BS_MAGIC
            && bootcode[0].mbr_bootsel_magic == LE_MBR_BS_MAGIC)
                copy_size = MBR_BS_OFFSET;
#endif

        if (bootsize != 0) {
                boot_installed = 1;
                memcpy(&mboot, bootcode, copy_size);
                mboot.mbr_bootsel_magic = bootcode[0].mbr_bootsel_magic;
        }
        mboot.mbr_magic = LE_MBR_MAGIC;

        if (!zappart)
                return;
        for (i = 0; i < MBR_PART_COUNT; i++)
                memset(&mboot.mbr_parts[i], 0, sizeof(mboot.mbr_parts[i]));
}

static void
get_extended_ptn(void)
{
        struct mbr_partition *mp;
        struct mbr_sector *boot;
        daddr_t offset;

        /* find first (there should only be one) extended partition */
        for (mp = mboot.mbr_parts; !MBR_IS_EXTENDED(mp->mbrp_type); mp++)
                if (mp >= &mboot.mbr_parts[MBR_PART_COUNT])
                        return;

        /*
         * The extended partition should be structured as a linked list
         * (even though it appears, at first glance, to be a tree).
         */
        ext.base = le32toh(mp->mbrp_start);
        ext.limit = ext.base + le32toh(mp->mbrp_size);
        ext.ptn_id = mp - mboot.mbr_parts;
        for (offset = 0;; offset = le32toh(boot->mbr_parts[1].mbrp_start)) {
                if (reallocarr(&ext.ptn,
                    ext.num_ptn + 1, sizeof(*ext.ptn)) != 0)
                        err(1, "Malloc failed");
                boot = ext.ptn + ext.num_ptn;
                if (read_s0(offset + ext.base, boot) == -1)
                        break;
                /* expect p0 to be valid and p1 to be another extended ptn */
                if (MBR_IS_EXTENDED(boot->mbr_parts[0].mbrp_type))
                        break;
                if (boot->mbr_parts[1].mbrp_type != 0 &&
                    !MBR_IS_EXTENDED(boot->mbr_parts[1].mbrp_type))
                        break;
                /* p2 and p3 should be unallocated */
                if (boot->mbr_parts[2].mbrp_type != 0 ||
                    boot->mbr_parts[3].mbrp_type != 0)
                        break;
                /* data ptn inside extended one */
                if (boot->mbr_parts[0].mbrp_type != 0 &&
                    offset + le32toh(boot->mbr_parts[0].mbrp_start)
                    + le32toh(boot->mbr_parts[0].mbrp_size) > ext.limit)
                        break;

                ext.num_ptn++;

                if (boot->mbr_parts[1].mbrp_type == 0)
                        /* end of extended partition chain */
                        return;
                /* must be in sector order */
                if (offset >= le32toh(boot->mbr_parts[1].mbrp_start))
                        break;
        }

        warnx("Extended partition table is corrupt");
        ext.is_corrupt = 1;
        ext.num_ptn = 0;
}

#if defined(USE_DISKLIST)
static void
get_diskname(const char *fullname, char *diskname, size_t size)
{
        const char *p, *p2;
        size_t len;

        p = strrchr(fullname, '/');
        if (p == NULL)
                p = fullname;
        else
                p++;

        if (*p == 0) {
                strlcpy(diskname, fullname, size);
                return;
        }

        if (*p == 'r')
                p++;

        for (p2 = p; *p2 != 0; p2++)
                if (isdigit((unsigned char)*p2))
                        break;
        if (*p2 == 0) {
                /* XXX invalid diskname? */
                strlcpy(diskname, fullname, size);
                return;
        }
        while (isdigit((unsigned char)*p2))
                p2++;

        len = p2 - p;
        if (len > size) {
                /* XXX */
                strlcpy(diskname, fullname, size);
                return;
        }

        memcpy(diskname, p, len);
        diskname[len] = 0;
}
#endif

static void
get_ptn_alignmemt(void)
{
        struct mbr_partition *partp = &mboot.mbr_parts[0];
        uint32_t ptn_0_base, ptn_0_limit;

        /* Default to using 'traditional' cylinder alignment */
        ptn_alignment = dos_cylindersectors;
        ptn_0_offset = dos_sectors;

        if (partp->mbrp_type != 0) {
                /* Try to copy alignment of first partition */
                ptn_0_base = le32toh(partp->mbrp_start);
                ptn_0_limit = ptn_0_base + le32toh(partp->mbrp_size);
                if (!(ptn_0_limit & 2047)) {
                        /* Partition ends on a 1MB boundary, align to 1MB */
                        ptn_alignment = 2048;
                        if (ptn_0_base <= 2048
                            && !(ptn_0_base & (ptn_0_base - 1))) {
                                /* ptn_base is a power of 2, use it */
                                ptn_0_offset = ptn_0_base;
                        }
                }
        } else {
                /* Use 1MB alignment for large disks */
                if (disksectors > 2048 * 1024 * 128) {
                        ptn_alignment = 2048;
                        ptn_0_offset = 2048;
                }
        }
}

static void
get_bios_geometry(void)
{
#if defined(USE_DISKLIST)
        int mib[2], i;
        size_t len;
        struct biosdisk_info *bip;
        struct nativedisk_info *nip;
        char diskname[8];

        mib[0] = CTL_MACHDEP;
        mib[1] = CPU_DISKINFO;
        if (sysctl(mib, 2, NULL, &len, NULL, 0) < 0) {
                goto out;
        }
        dl = (struct disklist *) malloc(len);
        if (dl == NULL)
                err(1, "Malloc failed");
        if (sysctl(mib, 2, dl, &len, NULL, 0) < 0) {
                free(dl);
                dl = 0;
                goto out;
        }

        get_diskname(disk, diskname, sizeof diskname);

        for (i = 0; i < dl->dl_nnativedisks; i++) {
                nip = &dl->dl_nativedisks[i];
                if (strcmp(diskname, nip->ni_devname))
                        continue;
                /*
                 * XXX listing possible matches is better. This is ok for
                 * now because the user has a chance to change it later.
                 * Also, if all the disks have the same parameters then we can
                 * just use them, we don't need to know which disk is which.
                 */
                if (nip->ni_nmatches != 0) {
                        bip = &dl->dl_biosdisks[nip->ni_biosmatches[0]];
                        dos_cylinders = bip->bi_cyl;
                        dos_heads = bip->bi_head;
                        dos_sectors = bip->bi_sec;
                        if (bip->bi_lbasecs)
                                dos_disksectors = bip->bi_lbasecs;
                        return;
                }
        }
 out:
#endif
        /* Allright, allright, make a stupid guess.. */
        intuit_translated_geometry();
}

#ifdef BOOTSEL
static daddr_t
get_default_boot(void)
{
        unsigned int id;
        int p;

        if (mboot.mbr_bootsel_magic != LE_MBR_BS_MAGIC)
                /* default to first active partition */
                return DEFAULT_ACTIVE;

        id = mboot.mbr_bootsel.mbrbs_defkey;

        if (mboot.mbr_bootsel.mbrbs_flags & MBR_BS_ASCII) {
                /* Keycode is ascii */
                if (id == '\r')
                    return DEFAULT_ACTIVE;
                /* '1'+ => allocated partition id, 'a'+ => disk 0+ */
                if (id >= 'a' && id < 'a' + MAX_BIOS_DISKS)
                        return DEFAULT_DISK(id - 'a');
                id -= '1';
        } else {
                /* keycode is PS/2 keycode */
                if (id == SCAN_ENTER)
                        return DEFAULT_ACTIVE;
                /* 1+ => allocated partition id, F1+ => disk 0+ */
                if (id >= SCAN_F1 && id < SCAN_F1 + MAX_BIOS_DISKS)
                        return DEFAULT_DISK(id - SCAN_F1);
                id -= SCAN_1;
        }

        /* Convert partition index to the invariant start sector number */

        for (p = 0; p < MBR_PART_COUNT; p++) {
                if (mboot.mbr_parts[p].mbrp_type == 0)
                        continue;
                if (mboot.mbr_bootsel.mbrbs_nametab[p][0] == 0)
                        continue;
                if (id-- == 0)
                        return le32toh(mboot.mbr_parts[p].mbrp_start);
        }

        for (p = 0; p < ext.num_ptn; p++) {
                if (ext.ptn[p].mbr_parts[0].mbrp_type == 0)
                        continue;
                if (ext.ptn[p].mbr_bootsel.mbrbs_nametab[0][0] == 0)
                        continue;
                if (id-- == 0)
                        return ext_offset(p)
                                + le32toh(ext.ptn[p].mbr_parts[0].mbrp_start);
        }

        return DEFAULT_ACTIVE;
}

static void
set_default_boot(daddr_t default_ptn)
{
        int p;
        static const unsigned char key_list[] = { SCAN_ENTER, SCAN_F1, SCAN_1,
                                                '\r', 'a', '1' };
        const unsigned char *key = key_list;

        if (mboot.mbr_bootsel_magic != LE_MBR_BS_MAGIC)
                /* sanity */
                return;

        if (mboot.mbr_bootsel.mbrbs_flags & MBR_BS_ASCII)
                /* Use ascii values */
                key += 3;

        if (default_ptn == DEFAULT_ACTIVE) {
                mboot.mbr_bootsel.mbrbs_defkey = key[0];
                return;
        }

        if (default_ptn >= DEFAULT_DISK(0)
            && default_ptn < DEFAULT_DISK(MAX_BIOS_DISKS)) {
                mboot.mbr_bootsel.mbrbs_defkey = key[1]
                    + default_ptn - DEFAULT_DISK(0);
                return;
        }

        mboot.mbr_bootsel.mbrbs_defkey = key[2];
        for (p = 0; p < MBR_PART_COUNT; p++) {
                if (mboot.mbr_parts[p].mbrp_type == 0)
                        continue;
                if (mboot.mbr_bootsel.mbrbs_nametab[p][0] == 0)
                        continue;
                if (le32toh(mboot.mbr_parts[p].mbrp_start) == default_ptn)
                        return;
                mboot.mbr_bootsel.mbrbs_defkey++;
        }

        if (mboot.mbr_bootsel.mbrbs_flags & MBR_BS_EXTLBA) {
                for (p = 0; p < ext.num_ptn; p++) {
                        if (ext.ptn[p].mbr_parts[0].mbrp_type == 0)
                                continue;
                        if (ext.ptn[p].mbr_bootsel.mbrbs_nametab[0][0] == 0)
                                continue;
                        if (le32toh(ext.ptn[p].mbr_parts[0].mbrp_start) +
                            ext_offset(p) == default_ptn)
                                return;
                        mboot.mbr_bootsel.mbrbs_defkey++;
                }
        }

        /* Default to first active partition */
        mboot.mbr_bootsel.mbrbs_defkey = key[0];
}

static void
install_bootsel(int needed)
{
        struct mbr_bootsel *mbs = &mboot.mbr_bootsel;
        int p;
        int ext13 = 0;
        const char *code;

        needed |= MBR_BS_NEWMBR;        /* need new bootsel code */

        /* Work out which boot code we need for this configuration */
        for (p = 0; p < MBR_PART_COUNT; p++) {
                if (mboot.mbr_parts[p].mbrp_type == 0)
                        continue;
                if (mboot.mbr_bootsel_magic != LE_MBR_BS_MAGIC)
                        break;
                if (mbs->mbrbs_nametab[p][0] == 0)
                        continue;
                needed |= MBR_BS_ACTIVE;
                if (le32toh(mboot.mbr_parts[p].mbrp_start) >= dos_totalsectors)
                        ext13 = MBR_BS_EXTINT13;
        }

        for (p = 0; p < ext.num_ptn; p++) {
                if (ext.ptn[p].mbr_bootsel_magic != LE_MBR_BS_MAGIC)
                        continue;
                if (ext.ptn[p].mbr_parts[0].mbrp_type == 0)
                        continue;
                if (ext.ptn[p].mbr_bootsel.mbrbs_nametab[p][0] == 0)
                        continue;
                needed |= MBR_BS_EXTLBA | MBR_BS_ACTIVE;
        }

        if (B_flag)
                needed |= MBR_BS_ACTIVE;

        /* Is the installed code good enough ? */
        if (!i_flag && (needed == 0 ||
            (mboot.mbr_bootsel_magic == LE_MBR_BS_MAGIC
            && (mbs->mbrbs_flags & needed) == needed))) {
                /* yes - just set flags */
                mbs->mbrbs_flags |= ext13;
                return;
        }

        /* ok - we need to replace the bootcode */

        if (f_flag && !(i_flag || B_flag)) {
                warnx("Installed bootfile doesn't support required options.");
                return;
        }

        if (!f_flag && bootsize == 0 && !i_flag)
                /* Output an explanation for the 'update bootcode' prompt. */
                printf("\n%s\n",
                    "Installed bootfile doesn't support required options.");

        /* Were we told a specific file ? (which we have already read) */
        /* If so check that it supports what we need. */
        if (bootsize != 0 && needed != 0
            && (bootcode[0].mbr_bootsel_magic != LE_MBR_BS_MAGIC
            || ((bootcode[0].mbr_bootsel.mbrbs_flags & needed) != needed))) {
                /* No it doesn't... */
                if (f_flag)
                        warnx("Bootfile %s doesn't support "
                                    "required bootsel options", boot_path );
                        /* But install it anyway */
                else
                        if (yesno("Bootfile %s doesn't support the required "
                            "options,\ninstall default bootfile instead?",
                            boot_path))
                                bootsize = 0;
        }

        if (bootsize == 0) {
                /* Get name of bootfile that supports the required facilities */
                code = DEFAULT_BOOTCODE;
                if (needed & MBR_BS_ACTIVE)
                        code = DEFAULT_BOOTSELCODE;
#ifdef DEFAULT_BOOTEXTCODE
                if (needed & MBR_BS_EXTLBA)
                        code = DEFAULT_BOOTEXTCODE;
#endif

                bootsize = read_boot(code, bootcode, sizeof bootcode, 0);
                if (bootsize == 0)
                        /* The old bootcode is better than no bootcode at all */
                        return;
                if ((bootcode[0].mbr_bootsel.mbrbs_flags & needed) != needed)
                        warnx("Default bootfile %s doesn't support required "
                                "options.  Got flags 0x%x, wanted 0x%x\n",
                                boot_path, bootcode[0].mbr_bootsel.mbrbs_flags,
                                needed);
        }

        if (!f_flag && !yesno("Update the bootcode from %s?", boot_path))
                return;

        init_sector0(0);

        if (mboot.mbr_bootsel_magic == LE_MBR_BS_MAGIC)
                mbs->mbrbs_flags = bootcode[0].mbr_bootsel.mbrbs_flags | ext13;
}

static daddr_t
configure_bootsel(daddr_t default_ptn)
{
        struct mbr_bootsel *mbs = &mboot.mbr_bootsel;
        int i, item, opt;
        int tmo;
        daddr_t *off;
        int num_bios_disks;

#if defined(USE_DISKLIST)
        if (dl != NULL) {
                num_bios_disks = dl->dl_nbiosdisks;
                if (num_bios_disks > MAX_BIOS_DISKS)
                        num_bios_disks = MAX_BIOS_DISKS;
        } else
#endif
                num_bios_disks = MAX_BIOS_DISKS;

        printf("\nBoot selector configuration:\n");

        /* The timeout value is in ticks, ~18.2 Hz. Avoid using floats.
         * Ticks are nearly 64k/3600 - so our long timers are slightly out!
         * Newer bootcode always waits for 1 tick, so treats 0xffff
         * as wait forever.
         */
        tmo = le16toh(mbs->mbrbs_timeo);
        tmo = tmo == 0xffff ? -1 : (10 * tmo + 9) / 182;
        tmo = decimal("Timeout value (0 to 3600 seconds, -1 => never)",
                        tmo, 0, -1, 3600);
        mbs->mbrbs_timeo = htole16(tmo == -1 ? 0xffff : (tmo * 182) / 10);

        off = calloc(1 + MBR_PART_COUNT + ext.num_ptn + num_bios_disks, sizeof *off);
        if (off == NULL)
                err(1, "Malloc failed");

        printf("Select the default boot option. Options are:\n\n");
        item = 0;
        opt = 0;
        off[opt] = DEFAULT_ACTIVE;
        printf("%d: The first active partition\n", opt);
        for (i = 0; i < MBR_PART_COUNT; i++) {
                if (mboot.mbr_parts[i].mbrp_type == 0)
                        continue;
                if (mbs->mbrbs_nametab[i][0] == 0)
                        continue;
                printf("%d: %s\n", ++opt, &mbs->mbrbs_nametab[i][0]);
                off[opt] = le32toh(mboot.mbr_parts[i].mbrp_start);
                if (off[opt] == default_ptn)
                        item = opt;
        }
        if (mbs->mbrbs_flags & MBR_BS_EXTLBA) {
                for (i = 0; i < ext.num_ptn; i++) {
                        if (ext.ptn[i].mbr_parts[0].mbrp_type == 0)
                                continue;
                        if (ext.ptn[i].mbr_bootsel.mbrbs_nametab[0][0] == 0)
                                continue;
                        printf("%d: %s\n",
                            ++opt, ext.ptn[i].mbr_bootsel.mbrbs_nametab[0]);
                        off[opt] = ext_offset(i) +
                            le32toh(ext.ptn[i].mbr_parts[0].mbrp_start);
                        if (off[opt] == default_ptn)
                                item = opt;
                }
        }
        for (i = 0; i < num_bios_disks; i++) {
                printf("%d: Harddisk %d\n", ++opt, i);
                off[opt] = DEFAULT_DISK(i);
                if (DEFAULT_DISK(i) == default_ptn)
                        item = opt;
        }

        item = decimal("Default boot option", item, 0, 0, opt);

        default_ptn = off[item];
        free(off);
        return default_ptn;
}
#endif /* BOOTSEL */


/* Prerequisite: the disklabel parameters and master boot record must
 *               have been read (i.e. dos_* and mboot are meaningful).
 * Specification: modifies dos_cylinders, dos_heads, dos_sectors, and
 *                dos_cylindersectors to be consistent with what the
 *                partition table is using, if we can find a geometry
 *                which is consistent with all partition table entries.
 *                We may get the number of cylinders slightly wrong (in
 *                the conservative direction).  The idea is to be able
 *                to create a NetBSD partition on a disk we don't know
 *                the translated geometry of.
 * This routine is only used for non-x86 systems or when we fail to
 * get the BIOS geometry from the kernel.
 */
static void
intuit_translated_geometry(void)
{
        uint32_t xcylinders;
        int xheads = -1, xsectors = -1, i, j;
        unsigned int c1, h1, s1, c2, h2, s2;
        unsigned long a1, a2;
        uint64_t num, denom;

        /*
         * The physical parameters may be invalid as bios geometry.
         * If we cannot determine the actual bios geometry, we are
         * better off picking a likely 'faked' geometry than leaving
         * the invalid physical one.
         */

        if (dos_cylinders > MAXCYL || dos_heads > MAXHEAD ||
            dos_sectors > MAXSECTOR) {
                h1 = MAXHEAD - 1;
                c1 = MAXCYL - 1;
#if defined(USE_DISKLIST)
                if (dl != NULL) {
                        /* BIOS may use 256 heads or 1024 cylinders */
                        for (i = 0; i < dl->dl_nbiosdisks; i++) {
                                if (h1 < (unsigned int)dl->dl_biosdisks[i].bi_head)
                                        h1 = dl->dl_biosdisks[i].bi_head;
                                if (c1 < (unsigned int)dl->dl_biosdisks[i].bi_cyl)
                                        c1 = dl->dl_biosdisks[i].bi_cyl;
                        }
                }
#endif
                dos_sectors = MAXSECTOR;
                dos_heads = h1;
                dos_cylinders = disklabel.d_secperunit / (MAXSECTOR * h1);
                if (dos_cylinders > c1)
                        dos_cylinders = c1;
        }

        /* Try to deduce the number of heads from two different mappings. */
        for (i = 0; i < MBR_PART_COUNT * 2 - 1; i++) {
                if (get_mapping(i, &c1, &h1, &s1, &a1) < 0)
                        continue;
                a1 -= s1;
                for (j = i + 1; j < MBR_PART_COUNT * 2; j++) {
                        if (get_mapping(j, &c2, &h2, &s2, &a2) < 0)
                                continue;
                        a2 -= s2;
                        num = (uint64_t)h1 * a2 - (uint64_t)h2 * a1;
                        denom = (uint64_t)c2 * a1 - (uint64_t)c1 * a2;
                        if (denom != 0 && num != 0 && num % denom == 0) {
                                xheads = num / denom;
                                xsectors = a1 / (c1 * xheads + h1);
                                break;
                        }
                }
                if (xheads != -1)
                        break;
        }

        if (xheads == -1) {
                if (F_flag)
                        return;
                warnx("Cannot determine the number of heads");
                return;
        }

        if (xsectors == -1) {
                warnx("Cannot determine the number of sectors");
                return;
        }

        /* Estimate the number of cylinders. */
        xcylinders = disklabel.d_secperunit / xheads / xsectors;
        if (disklabel.d_secperunit > xcylinders * xheads * xsectors)
                xcylinders++;

        /*
         * Now verify consistency with each of the partition table entries.
         * Be willing to shove cylinders up a little bit to make things work,
         * but translation mismatches are fatal.
         */
        for (i = 0; i < MBR_PART_COUNT * 2; i++) {
                if (get_mapping(i, &c1, &h1, &s1, &a1) < 0)
                        continue;
                if (c1 >= MAXCYL - 2)
                        continue;
                if (xsectors * (c1 * xheads + h1) + s1 != a1)
                        return;
        }


        /* Everything checks out.
         * Reset the geometry to use for further calculations.
         * But cylinders cannot be > 1024.
         */
        if (xcylinders > MAXCYL)
                dos_cylinders = MAXCYL;
        else
                dos_cylinders = xcylinders;
        dos_heads = xheads;
        dos_sectors = xsectors;
}

/*
 * For the purposes of intuit_translated_geometry(), treat the partition
 * table as a list of eight mapping between (cylinder, head, sector)
 * triplets and absolute sectors.  Get the relevant geometry triplet and
 * absolute sectors for a given entry, or return -1 if it isn't present.
 * Note: for simplicity, the returned sector is 0-based.
 */
static int
get_mapping(int i, unsigned int *cylinder, unsigned int *head, unsigned int *sector,
    unsigned long *absolute)
{
        struct mbr_partition *part = &mboot.mbr_parts[i / 2];

        if (part->mbrp_type == 0)
                return -1;
        if (i % 2 == 0) {
                *cylinder = MBR_PCYL(part->mbrp_scyl, part->mbrp_ssect);
                *head = part->mbrp_shd;
                *sector = MBR_PSECT(part->mbrp_ssect);
                *absolute = le32toh(part->mbrp_start);
        } else {
                *cylinder = MBR_PCYL(part->mbrp_ecyl, part->mbrp_esect);
                *head = part->mbrp_ehd;
                *sector = MBR_PSECT(part->mbrp_esect);
                *absolute = le32toh(part->mbrp_start)
                    + le32toh(part->mbrp_size) - 1;
        }
        /* Sanity check the data against all zeroes */
        if ((*cylinder == 0) && (*sector == 0) && (*head == 0))
                return -1;
        /* sector numbers in the MBR partition table start at 1 */
        *sector = *sector - 1;
        /* Sanity check the data against max values */
        if ((((*cylinder * MAXHEAD) + *head) * MAXSECTOR + *sector) < *absolute)
                /* cannot be a CHS mapping */
                return -1;
        return 0;
}

static void
delete_ptn(int part)
{
        if (part == ext.ptn_id) {
                /* forget all about the extended partition */
                free(ext.ptn);
                memset(&ext, 0, sizeof ext);
        }

        mboot.mbr_parts[part].mbrp_type = 0;
}

static void
delete_ext_ptn(int part)
{

        if (part == 0) {
                ext.ptn[0].mbr_parts[0].mbrp_type = 0;
                return;
        }
        ext.ptn[part - 1].mbr_parts[1] = ext.ptn[part].mbr_parts[1];
        memmove(&ext.ptn[part], &ext.ptn[part + 1],
                (ext.num_ptn - part - 1) * sizeof ext.ptn[0]);
        ext.num_ptn--;
}

static int
add_ext_ptn(daddr_t start, daddr_t size)
{
        int part;
        struct mbr_partition *partp;

        if (reallocarr(&ext.ptn, ext.num_ptn + 1, sizeof(*ext.ptn)) != 0)
                err(1, "reallocarr");
        for (part = 0; part < ext.num_ptn; part++)
                if (ext_offset(part) > start)
                        break;
        /* insert before 'part' - make space... */
        memmove(&ext.ptn[part + 1], &ext.ptn[part],
                (ext.num_ptn - part) * sizeof ext.ptn[0]);
        memset(&ext.ptn[part], 0, sizeof ext.ptn[0]);
        ext.ptn[part].mbr_magic = LE_MBR_MAGIC;
        /* we will be 'part' */
        if (part == 0) {
                /* link us to 'next' */
                partp = &ext.ptn[0].mbr_parts[1];
                /* offset will be fixed by caller */
                partp->mbrp_size = htole32(
                    le32toh(ext.ptn[1].mbr_parts[0].mbrp_start) +
                    le32toh(ext.ptn[1].mbr_parts[0].mbrp_size));
        } else {
                /* link us to prev's next */
                partp = &ext.ptn[part - 1].mbr_parts[1];
                ext.ptn[part].mbr_parts[1] = *partp;
                /* and prev onto us */
                partp->mbrp_start = htole32(start - ptn_0_offset - ext.base);
                partp->mbrp_size = htole32(size + ptn_0_offset);
        }
        partp->mbrp_type = 5;   /* as used by win98 */
        partp->mbrp_flag = 0;
        /* wallop in some CHS values - win98 doesn't saturate them */
        dos(le32toh(partp->mbrp_start),
            &partp->mbrp_scyl, &partp->mbrp_shd, &partp->mbrp_ssect);
        dos(le32toh(partp->mbrp_start) + le32toh(partp->mbrp_size) - 1,
            &partp->mbrp_ecyl, &partp->mbrp_ehd, &partp->mbrp_esect);
        ext.num_ptn++;

        return part;
}

static const char *
check_overlap(int part, int sysid, daddr_t start, daddr_t size, int fix)
{
        int p;
        unsigned int p_s, p_e;

        if (sysid != 0) {
                if (start == 0)
                        return "Sector zero is reserved for the MBR";
#if 0
                if (start < ptn_0_offset)
                        /* This is just a convention, not a requirement */
                        return "Track zero is reserved for the BIOS";
#endif
                if (start + size > disksectors)
                        return "Partition exceeds size of disk";
                for (p = 0; p < MBR_PART_COUNT; p++) {
                        if (p == part || mboot.mbr_parts[p].mbrp_type == 0)
                                continue;
                        p_s = le32toh(mboot.mbr_parts[p].mbrp_start);
                        p_e = p_s + le32toh(mboot.mbr_parts[p].mbrp_size);
                        if (start + size <= p_s || start >= p_e)
                                continue;
                        if (f_flag) {
                                if (fix)
                                        delete_ptn(p);
                                return 0;
                        }
                        return "Overlaps another partition";
                }
        }

        /* Are we trying to create an extended partition */
        if (!MBR_IS_EXTENDED(mboot.mbr_parts[part].mbrp_type)) {
                /* this wasn't the extended partition */
                if (!MBR_IS_EXTENDED(sysid))
                        return 0;
                /* making an extended partition */
                if (ext.base != 0) {
                        if (!f_flag)
                                return "There cannot be 2 extended partitions";
                        if (fix)
                                delete_ptn(ext.ptn_id);
                }
                if (fix) {
                        /* allocate a new extended partition */
                        ext.ptn = calloc(1, sizeof ext.ptn[0]);
                        if (ext.ptn == NULL)
                                err(1, "Malloc failed");
                        ext.ptn[0].mbr_magic = LE_MBR_MAGIC;
                        ext.ptn_id = part;
                        ext.base = start;
                        ext.limit = start + size;
                        ext.num_ptn = 1;
                }
                return 0;
        }

        /* Check we haven't cut space allocated to an extended ptn */

        if (!MBR_IS_EXTENDED(sysid)) {
                /* no longer an extended partition */
                if (fix) {
                        /* Kill all memory of the extended partitions */
                        delete_ptn(part);
                        return 0;
                }
                if (ext.num_ptn == 0 ||
                    (ext.num_ptn == 1 && ext.ptn[0].mbr_parts[0].mbrp_type == 0))
                        /* nothing in extended partition */
                        return 0;
                if (f_flag)
                        return 0;
                if (yesno("Do you really want to delete all the extended partitions?"))
                        return 0;
                return "Extended partition busy";
        }

        if (le32toh(mboot.mbr_parts[part].mbrp_start) != ext.base)
                /* maybe impossible, but an extra sanity check */
                return 0;

        for (p = ext.num_ptn; --p >= 0;) {
                if (ext.ptn[p].mbr_parts[0].mbrp_type == 0)
                        continue;
                p_s = ext_offset(p);
                p_e = p_s + le32toh(ext.ptn[p].mbr_parts[0].mbrp_start)
                          + le32toh(ext.ptn[p].mbr_parts[0].mbrp_size);
                if (p_s >= start && p_e <= start + size)
                        continue;
                if (!f_flag)
                        return "Extended partition outside main partition";
                if (fix)
                        delete_ext_ptn(p);
        }

        if (fix && start != ext.base) {
                /* The internal offsets need to be fixed up */
                for (p = 0; p < ext.num_ptn - 1; p++)
                        ext.ptn[p].mbr_parts[1].mbrp_start = htole32(
                            le32toh(ext.ptn[p].mbr_parts[1].mbrp_start)
                                    + ext.base - start);
                /* and maybe an empty partition at the start */
                if (ext.ptn[0].mbr_parts[0].mbrp_type == 0) {
                        if (le32toh(ext.ptn[0].mbr_parts[1].mbrp_start) == 0) {
                                /* don't need the empty slot */
                                memmove(&ext.ptn[0], &ext.ptn[1],
                                        (ext.num_ptn - 1) * sizeof ext.ptn[0]);
                                ext.num_ptn--;
                        }
                } else {
                        /* must create an empty slot */
                        add_ext_ptn(start, ptn_0_offset);
                        ext.ptn[0].mbr_parts[1].mbrp_start = htole32(ext.base
                                                                - start);
                }
        }
        if (fix) {
                ext.base = start;
                ext.limit = start + size;
        }
        return 0;
}

static const char *
check_ext_overlap(int part, int sysid, daddr_t start, daddr_t size, int fix)
{
        int p;
        unsigned int p_s, p_e;

        if (sysid == 0)
                return 0;

        if (MBR_IS_EXTENDED(sysid))
                return "Nested extended partitions are not allowed";

        /* allow one track at start for extended partition header */
        start -= ptn_0_offset;
        size += ptn_0_offset;
        if (start < ext.base || start + size > ext.limit)
                return "Outside bounds of extended partition";

        if (f_flag && !fix)
                return 0;

        for (p = ext.num_ptn; --p >= 0;) {
                if (p == part || ext.ptn[p].mbr_parts[0].mbrp_type == 0)
                        continue;
                p_s = ext_offset(p);
                p_e = p_s + le32toh(ext.ptn[p].mbr_parts[0].mbrp_start)
                        + le32toh(ext.ptn[p].mbr_parts[0].mbrp_size);
                if (p == 0)
                        p_s += le32toh(ext.ptn[p].mbr_parts[0].mbrp_start)
                                                        - ptn_0_offset;
                if (start < p_e && start + size > p_s) {
                        if (!f_flag)
                                return "Overlaps another extended partition";
                        if (fix) {
                                if (part == -1)
                                        delete_ext_ptn(p);
                                else
                                        /* must not change numbering yet */
                                        ext.ptn[p].mbr_parts[0].mbrp_type = 0;
                        }
                }
        }
        return 0;
}

static int
change_part(int extended, int part, int sysid, daddr_t start, daddr_t size,
        char *bootmenu)
{
        struct mbr_partition *partp;
        struct mbr_sector *boot;
        daddr_t offset;
        const char *e;
        int upart = part;
        int p;
        int fl;
        daddr_t n_s, n_e;
        const char *errtext;
#ifdef BOOTSEL
        char tmp_bootmenu[MBR_PART_COUNT * (MBR_BS_PARTNAMESIZE + 1)];
        int bootmenu_len = (extended ? MBR_PART_COUNT : 1) * (MBR_BS_PARTNAMESIZE + 1);
#endif

        if (extended) {
                if (part != -1 && part < ext.num_ptn) {
                        boot = &ext.ptn[part];
                        partp = &boot->mbr_parts[0];
                        offset = ext_offset(part);
                } else {
                        part = -1;
                        boot = 0;
                        partp = 0;
                        offset = 0;
                }
                upart = 0;
                e = "E";
        } else {
                boot = &mboot;
                partp = &boot->mbr_parts[part];
                offset = 0;
                e = "";
        }

        if (!f_flag && part != -1) {
                printf("The data for partition %s%d is:\n", e, part);
                print_part(boot, upart, offset);
        }

#ifdef BOOTSEL
        if (bootmenu != NULL)
                strlcpy(tmp_bootmenu, bootmenu, bootmenu_len);
        else
                if (boot != NULL && boot->mbr_bootsel_magic == LE_MBR_BS_MAGIC)
                        strlcpy(tmp_bootmenu,
                                boot->mbr_bootsel.mbrbs_nametab[upart],
                                bootmenu_len);
                else
                        tmp_bootmenu[0] = 0;
#endif

        if (partp != NULL) {
                if (!s_flag) {
                        /* values not specified, default to current ones */
                        sysid = partp->mbrp_type;
                        start = offset + le32toh(partp->mbrp_start);
                        size = le32toh(partp->mbrp_size);
                } else {
                        if (sysid == -1)
                                sysid = partp->mbrp_type;
                        if (start == (daddr_t)0xffffffff) {
                                start = offset + le32toh(partp->mbrp_start);
                                if (start == 0)
                                        start = offset = ptn_0_offset;
                        }
                        if (size == (daddr_t)0xffffffff) {
                                size = le32toh(partp->mbrp_size);
                                if (size == 0)
                                        size = disksectors - start;
                        }
                }
        }

        /* creating a new partition, default to free space */
        if (!s_flag && sysid == 0 && extended) {
                /* non-extended partition */
                start = ext.base;
                for (p = 0; p < ext.num_ptn; p++) {
                        if (ext.ptn[p].mbr_parts[0].mbrp_type == 0)
                                continue;
                        n_s = ext_offset(p);
                        if (n_s > start + ptn_0_offset)
                                break;
                        start = ext_offset(p)
                                + le32toh(ext.ptn[p].mbr_parts[0].mbrp_start)
                                + le32toh(ext.ptn[p].mbr_parts[0].mbrp_size);
                }
                if (ext.limit - start <= ptn_0_offset) {
                        printf("No space in extended partition\n");
                        return 0;
                }
                start += ptn_0_offset;
        }

        if (!s_flag && sysid == 0 && !extended) {
                /* same for non-extended partition */
                /* first see if old start is free */
                if (start < ptn_0_offset)
                        start = 0;
                for (p = 0; start != 0 && p < MBR_PART_COUNT; p++) {
                        if (mboot.mbr_parts[p].mbrp_type == 0)
                                continue;
                        n_s = le32toh(mboot.mbr_parts[p].mbrp_start);
                        if (start >= n_s &&
                            start < n_s + le32toh(mboot.mbr_parts[p].mbrp_size))
                                start = 0;
                }
                if (start == 0) {
                        /* Look for first gap */
                        start = ptn_0_offset;
                        for (p = 0; p < MBR_PART_COUNT; p++) {
                                if (mboot.mbr_parts[p].mbrp_type == 0)
                                        continue;
                                n_s = le32toh(mboot.mbr_parts[p].mbrp_start);
                                n_e = n_s + le32toh(mboot.mbr_parts[p].mbrp_size);
                                if (start >= n_s && start < n_e) {
                                        start = n_e;
                                        p = -1;
                                }
                        }
                        if (start >= disksectors && !I_flag) {
                                printf("No free space\n");
                                return 0;
                        }
                }
        }

        if (!f_flag) {
                /* request new values from user */
                if (sysid == 0)
                        sysid = 169;
                sysid = decimal("sysid", sysid, 0, 0, 255);
                if (sysid == 0 && !v_flag) {
                        start = 0;
                        size = 0;
#ifdef BOOTSEL
                        tmp_bootmenu[0] = 0;
#endif
                } else {
                        daddr_t old = start;
                        daddr_t lim = extended ? ext.limit : disksectors;
                        start = decimal("start", start,
                                DEC_SEC | DEC_RND_0 | (extended ? DEC_RND : 0),
                                extended ? ext.base : 0, lim);
                        /* Adjust 'size' so that end doesn't move when 'start'
                         * is only changed slightly.
                         */
                        if (size > start - old)
                                size -= start - old;
                        else
                                size = 0;
                        /* Find end of available space from this start point */
                        if (extended) {
                                for (p = 0; p < ext.num_ptn; p++) {
                                        if (p == part)
                                                continue;
                                        if (ext.ptn[p].mbr_parts[0].mbrp_type == 0)
                                                continue;
                                        n_s = ext_offset(p);
                                        if (n_s > start && n_s < lim)
                                                lim = n_s;
                                        if (start >= n_s && start < n_s
                                + le32toh(ext.ptn[p].mbr_parts[0].mbrp_start)
                                + le32toh(ext.ptn[p].mbr_parts[0].mbrp_size)) {
                                                lim = start;
                                                break;
                                        }
                                }
                        } else {
                                for (p = 0; p < MBR_PART_COUNT; p++) {
                                        if (p == part)
                                                continue;
                                        if (mboot.mbr_parts[p].mbrp_type == 0)
                                                continue;
                                        n_s = le32toh(mboot.mbr_parts[p].mbrp_start);
                                        if (n_s > start && n_s < lim)
                                                lim = n_s;
                                        if (start >= n_s && start < n_s
                                    + le32toh(mboot.mbr_parts[p].mbrp_size)) {
                                                lim = start;
                                                break;
                                        }
                                }
                        }
                        lim -= start;
                        if (lim == 0) {
                                printf("Start sector already allocated\n");
                                return 0;
                        }
                        if (size == 0 || size > lim)
                                size = lim;
                        fl = DEC_SEC;
                        if (start % ptn_alignment == ptn_0_offset)
                                fl |= DEC_RND_DOWN;
                        if (start == 2 * ptn_0_offset)
                                fl |= DEC_RND_DOWN | DEC_RND_DOWN_2;
                        size = decimal("size", size, fl, 0, lim);
#ifdef BOOTSEL
#ifndef DEFAULT_BOOTEXTCODE
                        if (!extended)
#endif
                                string("bootmenu", bootmenu_len, tmp_bootmenu);
#endif
                }
        }

        /*
         * Before we write these away, we must verify that nothing
         * untoward has been requested.
         */

        if (extended)
                errtext = check_ext_overlap(part, sysid, start, size, 0);
        else
                errtext = check_overlap(part, sysid, start, size, 0);
        if (errtext != NULL && !I_flag) {
                if (f_flag)
                        errx(2, "%s", errtext);
                printf("%s\n", errtext);
                return 0;
        }

        /*
         * Before proceeding, delete any overlapped partitions.
         * This can only happen if '-f' was supplied on the command line.
         * Just hope the caller knows what they are doing.
         * This also fixes the base of each extended partition if the
         * partition itself has moved.
         */
        if (!I_flag) {
                if (extended)
                        errtext = check_ext_overlap(part, sysid, start, size, 1);
                else
                        errtext = check_overlap(part, sysid, start, size, 1);
                if (errtext)
                        errx(1, "%s", errtext);
        }


        if (sysid == 0) {
                /* delete this partition - save info though */
                if (partp == NULL)
                        /* must have been trying to create an extended ptn */
                        return 0;
                if (start == 0 && size == 0)
                        memset(partp, 0, sizeof *partp);
#ifdef BOOTSEL
                if (boot->mbr_bootsel_magic == LE_MBR_BS_MAGIC)
                        memset(boot->mbr_bootsel.mbrbs_nametab[upart], 0,
                                sizeof boot->mbr_bootsel.mbrbs_nametab[0]);
#endif
                if (extended)
                        delete_ext_ptn(part);
                else
                        delete_ptn(part);
                return 1;
        }


        if (extended) {
                if (part != -1)
                        delete_ext_ptn(part);
                if (start == ext.base + ptn_0_offset)
                        /* First one must have been free */
                        part = 0;
                else
                        part = add_ext_ptn(start, size);

                /* These must be re-calculated because of the realloc */
                boot = &ext.ptn[part];
                partp = &boot->mbr_parts[0];
                offset = ext_offset(part);
        }

        partp->mbrp_type = sysid;
        partp->mbrp_start = htole32( start - offset);
        partp->mbrp_size = htole32( size);
        dos(start, &partp->mbrp_scyl, &partp->mbrp_shd, &partp->mbrp_ssect);
        dos(start + size - 1,
                    &partp->mbrp_ecyl, &partp->mbrp_ehd, &partp->mbrp_esect);
#ifdef BOOTSEL
        if (extended) {
                boot->mbr_bootsel_magic = LE_MBR_BS_MAGIC;
                strncpy(boot->mbr_bootsel.mbrbs_nametab[upart], tmp_bootmenu,
                        bootmenu_len);
        } else {
                /* We need to bootselect code installed in order to have
                 * somewhere to safely write the menu tag.
                 */
                if (boot->mbr_bootsel_magic != LE_MBR_BS_MAGIC) {
                        if (f_flag ||
                            yesno("The bootselect code is not installed, "
                                "do you want to install it now?"))
                                install_bootsel(MBR_BS_ACTIVE);
                }
                if (boot->mbr_bootsel_magic == LE_MBR_BS_MAGIC) {
                        strncpy(boot->mbr_bootsel.mbrbs_nametab[upart],
                                tmp_bootmenu, bootmenu_len);
                }
        }
#endif

        if (v_flag && !f_flag && yesno("Explicitly specify beg/end address?")) {
                /* this really isn't a good idea.... */
                int tsector, tcylinder, thead;

                tcylinder = MBR_PCYL(partp->mbrp_scyl, partp->mbrp_ssect);
                thead = partp->mbrp_shd;
                tsector = MBR_PSECT(partp->mbrp_ssect);
                tcylinder = decimal("beginning cylinder",
                                tcylinder, 0, 0, dos_cylinders - 1);
                thead = decimal("beginning head",
                                thead, 0, 0, dos_heads - 1);
                tsector = decimal("beginning sector",
                                tsector, 0, 1, dos_sectors);
                partp->mbrp_scyl = DOSCYL(tcylinder);
                partp->mbrp_shd = thead;
                partp->mbrp_ssect = DOSSECT(tsector, tcylinder);

                tcylinder = MBR_PCYL(partp->mbrp_ecyl, partp->mbrp_esect);
                thead = partp->mbrp_ehd;
                tsector = MBR_PSECT(partp->mbrp_esect);
                tcylinder = decimal("ending cylinder",
                                tcylinder, 0, 0, dos_cylinders - 1);
                thead = decimal("ending head",
                                thead, 0, 0, dos_heads - 1);
                tsector = decimal("ending sector",
                                tsector, 0, 1, dos_sectors);
                partp->mbrp_ecyl = DOSCYL(tcylinder);
                partp->mbrp_ehd = thead;
                partp->mbrp_esect = DOSSECT(tsector, tcylinder);
        }

        /* If we had to mark an extended partition as deleted because
         * another request would have overlapped it, now is the time
         * to do the actual delete.
         */
        if (extended && f_flag) {
                for (p = ext.num_ptn; --p >= 0;)
                        if (ext.ptn[p].mbr_parts[0].mbrp_type == 0)
                                delete_ext_ptn(p);
        }
        return 1;
}

static void
print_geometry(void)
{

        if (sh_flag) {
                printf("DISK=%s\n", disk);
                printf("DLCYL=%d\nDLHEAD=%d\nDLSEC=%d\nDLSIZE=%"PRIdaddr"\n",
                        cylinders, heads, sectors, disksectors);
                printf("BCYL=%d\nBHEAD=%d\nBSEC=%d\nBDLSIZE=%"PRIdaddr"\n",
                        dos_cylinders, dos_heads, dos_sectors, dos_disksectors);
                printf("NUMEXTPTN=%d\n", ext.num_ptn);
                return;
        }

        /* Not sh_flag */
        printf("Disk: %s\n", disk);
        printf("NetBSD disklabel disk geometry:\n");
        printf("cylinders: %d, heads: %d, sectors/track: %d "
            "(%d sectors/cylinder)\ntotal sectors: %"PRIdaddr", "
            "bytes/sector: %zd\n\n", cylinders, heads, sectors,
            cylindersectors, disksectors, secsize);
        printf("BIOS disk geometry:\n");
        printf("cylinders: %d, heads: %d, sectors/track: %d "
            "(%d sectors/cylinder)\ntotal sectors: %"PRIdaddr"\n\n",
            dos_cylinders, dos_heads, dos_sectors, dos_cylindersectors,
            dos_disksectors);
        printf("Partitions aligned to %d sector boundaries, offset %d\n\n",
            ptn_alignment, ptn_0_offset);
}

/* Find the first active partition, else return MBR_PART_COUNT */
static int
first_active(void)
{
        struct mbr_partition *partp = &mboot.mbr_parts[0];
        int part;

        for (part = 0; part < MBR_PART_COUNT; part++)
                if (partp[part].mbrp_flag & MBR_PFLAG_ACTIVE)
                        return part;
        return MBR_PART_COUNT;
}

static void
change_active(int which)
{
        struct mbr_partition *partp;
        int part;
        int active = MBR_PART_COUNT;

        partp = &mboot.mbr_parts[0];

        if (a_flag && which != -1)
                active = which;
        else
                active = first_active();
        if (!f_flag) {
                if (yesno("Do you want to change the active partition?")) {
                        printf ("Choosing %d will make no partition active.\n",
                            MBR_PART_COUNT);
                        do {
                                active = decimal("active partition",
                                                active, 0, 0, MBR_PART_COUNT);
                        } while (!yesno("Are you happy with this choice?"));
                } else
                        return;
        } else
                if (active != MBR_PART_COUNT)
                        printf ("Making partition %d active.\n", active);

        for (part = 0; part < MBR_PART_COUNT; part++)
                partp[part].mbrp_flag &= ~MBR_PFLAG_ACTIVE;
        if (active < MBR_PART_COUNT)
                partp[active].mbrp_flag |= MBR_PFLAG_ACTIVE;
}

static void
change_bios_geometry(void)
{
        print_geometry();
        if (!yesno("Do you want to change our idea of what BIOS thinks?"))
                return;

#if defined(USE_DISKLIST)
        if (dl != NULL) {
                struct biosdisk_info *bip;
                int i;

                for (i = 0; i < dl->dl_nbiosdisks; i++) {
                        if (i == 0)
                                printf("\nGeometries of known disks:\n");
                        bip = &dl->dl_biosdisks[i];
                        printf("Disk %d: cylinders %u, heads %u, sectors %u"
                                " (%"PRIdaddr" sectors, %dMB)\n",
                            i, bip->bi_cyl, bip->bi_head, bip->bi_sec,
                            bip->bi_lbasecs, SEC_TO_MB(bip->bi_lbasecs));
                }
                printf("\n");
        }
#endif
        do {
                dos_cylinders = decimal("BIOS's idea of #cylinders",
                                        dos_cylinders, 0, 0, MAXCYL);
                dos_heads = decimal("BIOS's idea of #heads",
                                        dos_heads, 0, 0, MAXHEAD);
                dos_sectors = decimal("BIOS's idea of #sectors",
                                        dos_sectors, 0, 1, MAXSECTOR);
                print_geometry();
        } while (!yesno("Are you happy with this choice?"));
}


/***********************************************\
* Change real numbers into strange dos numbers  *
\***********************************************/
static void
dos(int sector, unsigned char *cylinderp, unsigned char *headp,
    unsigned char *sectorp)
{
        int cylinder, head;

        cylinder = sector / dos_cylindersectors;
        sector -= cylinder * dos_cylindersectors;

        head = sector / dos_sectors;
        sector -= head * dos_sectors;
        if (cylinder > 1023)
                cylinder = 1023;

        *cylinderp = DOSCYL(cylinder);
        *headp = head;
        *sectorp = DOSSECT(sector + 1, cylinder);
}

static int
open_disk(int update)
{
        static char namebuf[MAXPATHLEN + 1];
        int flags = update && disk_file == NULL ? O_RDWR : O_RDONLY;

        if (!F_flag) {
                fd = opendisk(disk, flags, namebuf, sizeof(namebuf), 0);
                if (fd < 0) {
                        if (errno == ENODEV)
                                warnx("%s is not a character device", namebuf);
                        else
                                warn("cannot opendisk %s", namebuf);
                        return -1;
                }
                disk = namebuf;
        } else {
                fd = open(disk, flags, 0);
                if (fd == -1) {
                        warn("cannot open %s", disk);
                        return -1;
                }
        }

        if (get_params() == -1) {
                close(fd);
                fd = -1;
                return -1;
        }
        if (disk_file != NULL) {
                /* for testing: read/write data from a disk file */
                wfd = open(disk_file, update ? O_RDWR|O_CREAT : O_RDONLY, 0777);
                if (wfd == -1) {
                        warn("%s", disk_file);
                        close(fd);
                        fd = -1;
                        return -1;
                }
        } else
                wfd = fd;
        return 0;
}

static ssize_t
read_disk(daddr_t sector, void *buf)
{
        ssize_t nr;

        if (*rfd == -1)
                errx(1, "read_disk(); fd == -1");

        if (secsize <= 0)
                errx(1, "read_disk(); secsize invalid");

        off_t offs = sector * (off_t)secsize;
        off_t mod = offs & (secsize - 1);
        off_t rnd = offs & ~(secsize - 1);

        if (lseek(*rfd, rnd, SEEK_SET) == (off_t)-1)
                return -1;

        if (secsize <= 512)
                return read(*rfd, buf, secsize);

        if ((nr = read(*rfd, iobuf, secsize)) != secsize)
                return nr;

        memcpy(buf, &iobuf[mod], 512);

        return 512;
}

static ssize_t
write_disk(daddr_t sector, void *buf)
{
        ssize_t nr;

        if (wfd == -1)
                errx(1, "write_disk(); wfd == -1");

        off_t offs = sector * (off_t)secsize;
        off_t mod = offs & (secsize - 1);
        off_t rnd = offs & ~(secsize - 1);

        if (lseek(wfd, rnd, SEEK_SET) == (off_t)-1)
                return -1;

        if (secsize == 512)
                return write(wfd, buf, 512);

        if ((nr = read(wfd, iobuf, secsize)) != secsize)
                return nr;

        if (lseek(wfd, rnd, SEEK_SET) == (off_t)-1)
                return -1;

        memcpy(&iobuf[mod], buf, 512);

        if ((nr = write(wfd, iobuf, secsize)) != secsize)
                return nr;

        return 512;
}

static void
guess_geometry(daddr_t _sectors)
{
        dos_sectors = MAXSECTOR;
        dos_heads = MAXHEAD - 1;        /* some BIOS might use 256 */
        dos_cylinders = _sectors / (MAXSECTOR * (MAXHEAD - 1));
        if (dos_cylinders < 1)
                dos_cylinders = 1;
        else if (dos_cylinders > MAXCYL - 1)
                dos_cylinders = MAXCYL - 1;
}

static int
get_params(void)
{
        if (F_flag) {
                struct stat st;
                if (fstat(fd, &st) == -1) {
                        warn("%s: fstat", disk);
                        return -1;
                }
                if (st.st_size % 512 != 0) {
                        warnx("%s size (%ju) is not divisible "
                            "by sector size (%d)", disk, (uintmax_t)st.st_size,
                            512);
                }
                disklabel.d_secperunit = st.st_size / 512;
                guess_geometry(disklabel.d_secperunit);
                disklabel.d_ncylinders = dos_cylinders;
                disklabel.d_ntracks = dos_heads;
                disklabel.d_secsize = 512;
                disklabel.d_nsectors = dos_sectors;
        }
#if !HAVE_NBTOOL_CONFIG_H
        else if (ioctl(fd, DIOCGDEFLABEL, &disklabel) == -1) {
                warn("%s: DIOCGDEFLABEL", disk);
                if (ioctl(fd, DIOCGDINFO, &disklabel) == -1) {
                        warn("%s: DIOCGDINFO", disk);
                        return -1;
                }
        }
#endif

        disksectors = disklabel.d_secperunit;
        cylinders = disklabel.d_ncylinders;
        heads = disklabel.d_ntracks;
        secsize = disklabel.d_secsize;
        sectors = disklabel.d_nsectors;

        /* pick up some defaults for the BIOS sizes */
        if (sectors <= MAXSECTOR) {
                dos_cylinders = cylinders;
                dos_heads = heads;
                dos_sectors = sectors;
        } else {
                /* guess - has to better than the above */
                guess_geometry(disksectors);
        }
        dos_disksectors = disksectors;

        return 0;
}

#ifdef BOOTSEL
/*
 * Rather unfortunately the bootsel 'magic' number is at the end of the
 * the structure, and there is no checksum.  So when other operating
 * systems install mbr code by only writing the length of their code they
 * can overwrite part of the structure but keeping the magic number intact.
 * This code attempts to empirically detect this problem.
 */
static int
validate_bootsel(struct mbr_bootsel *mbs)
{
        unsigned int key = mbs->mbrbs_defkey;
        unsigned int tmo;
        size_t i, j;

        if (v_flag)
                return 0;

        /*
         * Check default key is sane
         * - this is the most likely field to be stuffed
         * 16 disks and 16 bootable partitions seems enough!
         * (the keymap decode starts falling apart at that point)
         */
        if (mbs->mbrbs_flags & MBR_BS_ASCII) {
                if (key != 0 && !(key == '\r'
                    || (key >= '1' && key < '1' + MAX_BIOS_DISKS)
                    || (key >= 'a' && key < 'a' + MAX_BIOS_DISKS)))
                        return 1;
        } else {
                if (key != 0 && !(key == SCAN_ENTER
                    || (key >= SCAN_1 && key < SCAN_1 + MAX_BIOS_DISKS)
                    || (key >= SCAN_F1 && key < SCAN_F1 + MAX_BIOS_DISKS)))
                        return 1;
        }

        /* Checking the flags will lead to breakage... */

        /* Timeout value is expected to be a multiple of a second */
        tmo = htole16(mbs->mbrbs_timeo);
        if (tmo != 0 && tmo != 0xffff && tmo != (10 * tmo + 9) / 182 * 182 / 10)
                return 2;

        /* Check the menu strings are printable */
        /* Unfortunately they aren't zero filled... */
        for (j = 0; j < __arraycount(mbs->mbrbs_nametab); ++j)
        for (i = 0; i < sizeof(mbs->mbrbs_nametab[j]); i++) {
                int c = (uint8_t)mbs->mbrbs_nametab[j][i];
                if (c == 0 || isprint(c))
                        continue;
                return 3;
        }

        return 0;
}
#endif

static int
read_s0(daddr_t offset, struct mbr_sector *boot)
{
        const char *tabletype = offset ? "extended" : "primary";
#ifdef BOOTSEL
        static int reported;
#endif

        if (read_disk(offset, boot) == -1) {
                warn("Can't read %s partition table", tabletype);
                return -1;
        }
        if (boot->mbr_magic != LE_MBR_MAGIC) {
                if (F_flag && boot->mbr_magic == 0)
                        return -1;
                warnx("%s partition table invalid, "
                    "no magic in sector %"PRIdaddr, tabletype, offset);
                return -1;

        }
#ifdef BOOTSEL
        if (boot->mbr_bootsel_magic == LE_MBR_BS_MAGIC) {
                /* mbr_bootsel in new location */
                if (validate_bootsel(&boot->mbr_bootsel)) {
                        warnx("removing corrupt bootsel information");
                        boot->mbr_bootsel_magic = 0;
                }
                return 0;
        }
        if (boot->mbr_bootsel_magic != LE_MBR_MAGIC)
                return 0;

        /* mbr_bootsel in old location */
        if (!reported)
                warnx("%s partition table: using old-style bootsel information",
                    tabletype);
        reported = 1;
        if (validate_bootsel((void *)((uint8_t *)boot + MBR_BS_OFFSET + 4))) {
                warnx("%s bootsel information corrupt - ignoring", tabletype);
                return 0;
        }
        memmove((uint8_t *)boot + MBR_BS_OFFSET,
                (uint8_t *)boot + MBR_BS_OFFSET + 4,
                sizeof(struct mbr_bootsel));
        if ( ! (boot->mbr_bootsel.mbrbs_flags & MBR_BS_NEWMBR)) {
                        /* old style default key */
                int id;
                        /* F1..F4 => ptn 0..3, F5+ => disk 0+ */
                id = boot->mbr_bootsel.mbrbs_defkey;
                id -= SCAN_F1;
                if (id >= MBR_PART_COUNT)
                        id -= MBR_PART_COUNT; /* Use number of disk */
                else if (mboot.mbr_parts[id].mbrp_type != 0)
                        id = le32toh(boot->mbr_parts[id].mbrp_start);
                else
                        id = DEFAULT_ACTIVE;
                boot->mbr_bootsel.mbrbs_defkey = id;
        }
        boot->mbr_bootsel_magic = LE_MBR_BS_MAGIC;
                /* highlight that new bootsel code is necessary */
        boot->mbr_bootsel.mbrbs_flags &= ~MBR_BS_NEWMBR;
#endif /* BOOTSEL */
        return 0;
}

static int
write_mbr(void)
{
        int flag, i;
        daddr_t offset;
        int rval = -1;

        /*
         * write enable label sector before write (if necessary),
         * disable after writing.
         * needed if the disklabel protected area also protects
         * sector 0. (e.g. empty disk)
         */
        flag = 1;
#if !HAVE_NBTOOL_CONFIG_H
        if (wfd == fd && F_flag == 0 && ioctl(wfd, DIOCWLABEL, &flag) < 0)
                warn("DIOCWLABEL");
#endif
        if (write_disk(0, &mboot) == -1) {
                warn("Can't write fdisk partition table");
                goto protect_label;
        }
        if (boot_installed)
                for (i = bootsize; (i -= 0x200) > 0;)
                        if (write_disk(i / 0x200, &bootcode[i / 0x200]) == -1) {
                                warn("Can't write bootcode");
                                goto protect_label;
                        }
        for (offset = 0, i = 0; i < ext.num_ptn; i++) {
                if (write_disk(ext.base + offset, ext.ptn + i) == -1) {
                        warn("Can't write %dth extended partition", i);
                        goto protect_label;
                }
                offset = le32toh(ext.ptn[i].mbr_parts[1].mbrp_start);
        }
        rval = 0;
    protect_label:
        flag = 0;
#if !HAVE_NBTOOL_CONFIG_H
        if (wfd == fd && F_flag == 0 && ioctl(wfd, DIOCWLABEL, &flag) < 0)
                warn("DIOCWLABEL");
#endif
        return rval;
}

static int
yesno(const char *str, ...)
{
        int ch, first;
        va_list ap;

        va_start(ap, str);
        vprintf(str, ap);
        va_end(ap);
        printf(" [n] ");

        first = ch = getchar();
        while (ch != '\n' && ch != EOF)
                ch = getchar();
        if (ch == EOF)
                errx(1, "EOF");
        return first == 'y' || first == 'Y';
}

static int64_t
decimal(const char *prompt, int64_t dflt, int flags, int64_t minval, int64_t maxval)
{
        int64_t acc = 0;
        int valid;
        int len;
        char *cp;

        for (;;) {
                if (flags & DEC_SEC) {
                        printf("%s: [%" PRId64 "..%" PRId64 "cyl default: %" PRId64 ", %" PRId64 "cyl, %uMB] ",
                            prompt, SEC_TO_CYL(minval), SEC_TO_CYL(maxval),
                            dflt, SEC_TO_CYL(dflt), SEC_TO_MB(dflt));
                } else
                        printf("%s: [%" PRId64 "..%" PRId64 " default: %" PRId64 "] ",
                            prompt, minval, maxval, dflt);

                if (!fgets(lbuf, LBUF, stdin))
                        errx(1, "EOF");
                cp = lbuf;

                cp += strspn(cp, " \t");
                if (*cp == '\n')
                        return dflt;

                if (cp[0] == '$' && cp[1] == '\n')
                        return maxval;

                if (isdigit((unsigned char)*cp) || *cp == '-') {
                        acc = strtoll(lbuf, &cp, 10);
                        len = strcspn(cp, " \t\n");
                        valid = 0;
                        if (len != 0 && (flags & DEC_SEC)) {
                                if (!strncasecmp(cp, "gb", len)) {
                                        acc *= 1024;
                                        valid = 1;
                                }
                                if (valid || !strncasecmp(cp, "mb", len)) {
                                        acc *= SEC_IN_1M;
                                        /* round to whole number of cylinders */
                                        acc += ptn_alignment / 2;
                                        acc /= ptn_alignment;
                                        valid = 1;
                                }
                                if (valid || !strncasecmp(cp, "cyl", len)) {
                                        acc *= ptn_alignment;
                                        /* adjustments for cylinder boundary */
                                        if (acc == 0 && flags & DEC_RND_0)
                                                acc += ptn_0_offset;
                                        if (flags & DEC_RND)
                                                acc += ptn_0_offset;
                                        if (flags & DEC_RND_DOWN)
                                                acc -= ptn_0_offset;
                                        if (flags & DEC_RND_DOWN_2)
                                                acc -= ptn_0_offset;
                                        cp += len;
                                }
                        }
                }

                cp += strspn(cp, " \t");
                if (*cp != '\n') {
                        lbuf[strlen(lbuf) - 1] = 0;
                        printf("%s is not a valid %s number.\n", lbuf,
                            flags & DEC_SEC ? "sector" : "decimal");
                        continue;
                }

                if (acc >= minval && acc <= maxval)
                        return acc;
                printf("%" PRId64 " is not between %" PRId64 " and %" PRId64 ".\n", acc, minval, maxval);
        }
}

static int
ptn_id(const char *prompt, int *extended)
{
        unsigned int acc = 0;
        char *cp;

        for (;; printf("%s is not a valid partition number.\n", lbuf)) {
                printf("%s: [none] ", prompt);

                if (!fgets(lbuf, LBUF, stdin))
                        errx(1, "EOF");
                lbuf[strlen(lbuf)-1] = '\0';
                cp = lbuf;

                cp += strspn(cp, " \t");
                *extended = 0;
                if (*cp == 0)
                        return -1;

                if (*cp == 'E' || *cp == 'e') {
                        cp++;
                        *extended = 1;
                }

                acc = strtoul(cp, &cp, 10);

                cp += strspn(cp, " \t");
                if (*cp != '\0')
                        continue;

                if (*extended || acc < MBR_PART_COUNT)
                        return acc;
        }
}

#ifdef BOOTSEL
static void
string(const char *prompt, int length, char *buf)
{
        int len;

        for (;;) {
                printf("%s: [%.*s] (space to clear)", prompt, length, buf);

                if (!fgets(lbuf, LBUF, stdin))
                        errx(1, "EOF");
                len = strlen(lbuf);
                if (len <= 1)
                        /* unchanged if just <enter> */
                        return;
                /* now strip trailing spaces, <space><enter> deletes string */
                do
                        lbuf[--len] = 0;
                while (len != 0 && lbuf[len - 1] == ' ');
                if (len < length)
                        break;
                printf("'%s' is longer than %d characters.\n",
                    lbuf, length - 1);
        }
        strncpy(buf, lbuf, length);
}
#endif

static int
type_match(const void *key, const void *item)
{
        const int *idp = key;
        const struct mbr_ptype *ptr = item;

        if (*idp < ptr->id)
                return -1;
        if (*idp > ptr->id)
                return 1;
        return 0;
}

static const char *
get_type(int type)
{
        const struct mbr_ptype *ptr;

        ptr = bsearch(&type, mbr_ptypes, KNOWN_SYSIDS,
            sizeof(mbr_ptypes[0]), type_match);
        if (ptr == NULL)
                return "unknown";
        return ptr->name;
}

static int
read_gpt(daddr_t offset, struct gpt_hdr *gptp)
{
        char buf[512];
        struct gpt_hdr *hdr = (void *)buf;
        const char *tabletype = GPT_TYPE(offset);

        if (read_disk(offset, buf) == -1) {
                warn("Can't read %s GPT header", tabletype);
                return -1;
        }
        (void)memcpy(gptp, buf, GPT_HDR_SIZE);

        /* GPT CRC should be calculated with CRC field preset to zero */
        hdr->hdr_crc_self = 0;

        if (memcmp(gptp->hdr_sig, GPT_HDR_SIG, sizeof(gptp->hdr_sig))
            || gptp->hdr_lba_self != (uint64_t)offset
            || crc32(0, (void *)hdr, gptp->hdr_size) != gptp->hdr_crc_self) {
                /* not a GPT */
                (void)memset(gptp, 0, GPT_HDR_SIZE);
        }

        if (v_flag && gptp->hdr_size != 0) {
                printf("Found %s GPT header CRC %"PRIu32" "
                    "at sector %"PRIdaddr", backup at %"PRIdaddr"\n",
                    tabletype, gptp->hdr_crc_self, offset, gptp->hdr_lba_alt);
        }
        return gptp->hdr_size;

}

static int
delete_gpt(struct gpt_hdr *gptp)
{
        char buf[512];
        struct gpt_hdr *hdr = (void *)buf;

        if (g_flag)
                return 0;       /* preserve existing GPT headers */

        if (gptp->hdr_size == 0)
                return 0;

        /* don't accidently overwrite something important */
        if (gptp->hdr_lba_self != GPT_HDR_BLKNO &&
            gptp->hdr_lba_self != (uint64_t)disksectors - 1) {
                warnx("given GPT header location doesn't seem correct");
                return -1;
        }

        (void)memcpy(buf, gptp, GPT_HDR_SIZE);
        /*
         * Don't really delete GPT, just "disable" it, so it can
         * be recovered later in case of mistake or something
         */
        (void)memset(hdr->hdr_sig, 0, sizeof(gptp->hdr_sig));
        if (write_disk(gptp->hdr_lba_self, hdr) == -1) {
                warn("can't delete %s GPT header",
                    GPT_TYPE(gptp->hdr_lba_self));
                return -1;
        }
        (void)memset(gptp, 0, GPT_HDR_SIZE);
        return 1;
}