boot/mbr/mbr.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <sys/types.h>
#include <string.h>
#include <fcntl.h>
#include <libgen.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <sys/dktp/fdisk.h>

#define SECTOR_SIZE 512
static char boot_sect[SECTOR_SIZE];
static char new_mboot[SECTOR_SIZE];

static void
usage(char *progname)
{
    fprintf(stderr, "Usage: %s [ -d | -n | -o | -r ] <device> [<mboot>]\n",
        basename(progname));
    fprintf(stderr, "\t-n Set new Solaris partition magic 0xbf\n");
    fprintf(stderr, "\t-o Set old Solaris partition magic 0x82\n");
    fprintf(stderr, "\t-r Replace master boot program "
        "(/usr/lib/fs/ufs/mboot)\n");
    exit(-1);
}

int
main(int argc, char *argv[])
{
    int c, fd, i, sol_part = -1;
    int setold = 0, setnew = 0, write_mboot = 0, list_hd = 0;
    char *device;
    struct mboot *mboot;
    char *mboot_file = "/usr/lib/fs/ufs/mboot";

    while ((c = getopt(argc, argv, "dnor")) != EOF) {
        switch (c) {
        case 'd':
            list_hd = 1;
            continue;
        case 'n':
            setnew = 1;
            continue;
        case 'o':
            setold = 1;
            continue;
        case 'r':
            write_mboot = 1;
            continue;
        default:
            usage(argv[0]);
        }
    }

    /* check arguments */
    if ((setnew && setold) || argc < optind + 1) {
        usage(argv[0]);
    }

    if (write_mboot && argc > optind + 1) {
        mboot_file = strdup(argv[optind + 1]);
    }
    if (!mboot_file) {
        usage(argv[0]);
    }
    fd = open(mboot_file, O_RDONLY);
    if (fd == -1 || read(fd, new_mboot, SECTOR_SIZE) != SECTOR_SIZE) {
        fprintf(stderr, "cannot read file %s\n", mboot_file);
        if (fd == -1)
            perror("open");
        else
            perror("read");
        exit(-1);
    }
    close(fd);

    device = strdup(argv[optind]);
    if (!device) {
        usage(argv[0]);
    }
    fd = open(device, O_RDWR);
    if (fd == -1 || read(fd, boot_sect, SECTOR_SIZE) != SECTOR_SIZE) {
        fprintf(stderr, "cannot read MBR on %s\n", device);
        if (fd == -1)
            perror("open");
        else
            perror("read");
        exit(-1);
    }

    mboot = (struct mboot *)boot_sect;
    for (i = 0; i < FD_NUMPART; i++) {
        struct ipart *part = (struct ipart *)mboot->parts + i;
        if (!list_hd) {
            if (part->bootid == 128)
                printf("active ");
            else
                printf("       ");
        }
        if (setnew && part->systid == 0x82) {
            part->systid = 0xbf;
            sol_part = i;
        } else if (setold && part->systid == 0xbf) {
            part->systid = 0x82;
            sol_part = i;
        } else if (list_hd &&
            (part->systid == 0x82 || part->systid == 0xbf)) {
            sol_part = i;
        }
        if (!list_hd)
            printf("%d (0x%2x): start_sect %u, size_sect %u\n",
                i + 1, part->systid, part->relsect, part->numsect);
    }

    if (list_hd) {
        printf("(hd0,%d,a)\n", sol_part);
        (void) close(fd);
        return (0);
    }

    /* write new mboot */
    if (write_mboot || sol_part != -1) {
        if (write_mboot) {
            /* copy over the new boot program */
            bcopy((void *)new_mboot, (void *)boot_sect, BOOTSZ);
        }

        if ((lseek(fd, 0, SEEK_SET) < 0) ||
            (write(fd, (void *)boot_sect, SECTOR_SIZE) < 0)) {
            perror("failed to update MBR");
            exit(-1);
        }
        if (sol_part != -1) {
            printf("Changed solaris partition %d", sol_part + 1);
            if (setnew)
                printf("from 0x82 to 0xbf\n");
            else
                printf("from 0xbf to 0x82\n");
        }
        if (write_mboot) {
            printf("Replaced mboot program with %s\n", mboot_file);
        }
    }

    (void) close(fd);
    return (0);
}