xref: /freebsd-10.1-release/usr.bin/mkimg/mbr.c

/*-
 * Copyright (c) 2014 Juniper Networks, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: user/marcel/mkimg/mbr.c 263652 2014-03-22 23:34:35Z marcel $");

#include <sys/types.h>
#include <sys/diskmbr.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "mkimg.h"
#include "scheme.h"

static struct mkimg_alias mbr_aliases[] = {
    {	ALIAS_FREEBSD, ALIAS_INT2TYPE(DOSPTYP_386BSD) },
    {	ALIAS_NONE, 0 }		/* Keep last! */
};

static u_int
mbr_metadata(u_int where, u_int parts __unused, u_int secsz __unused)
{
	u_int secs;

	secs = (where == SCHEME_META_IMG_START) ? 1 : 0;
	return (secs);
}

static int
mbr_write(int fd, off_t imgsz __unused, u_int parts __unused, u_int secsz,
    void *bootcode)
{
	u_char *mbr;
	struct dos_partition *dpbase, *dp;
	struct part *part;

	mbr = malloc(secsz);
	if (mbr == NULL)
		return (ENOMEM);
	if (bootcode != NULL) {
		memcpy(mbr, bootcode, DOSPARTOFF);
		memset(mbr + DOSPARTOFF, 0, secsz - DOSPARTOFF);
	} else
		memset(mbr, 0, secsz);
	dpbase = (void *)(mbr + DOSPARTOFF);
	STAILQ_FOREACH(part, &partlist, link) {
		dp = dpbase + part->index;
		dp->dp_flag = (part->index == 0 && bootcode != NULL) ? 0x80 : 0;
		dp->dp_shd = dp->dp_ssect = dp->dp_scyl = 0xff;	/* XXX */
		dp->dp_typ = ALIAS_TYPE2INT(part->type);
		dp->dp_ehd = dp->dp_esect = dp->dp_ecyl = 0xff;	/* XXX */
		le32enc(&dp[part->index].dp_start, part->offset / secsz);
		le32enc(&dp[part->index].dp_size, part->size / secsz);
	}
	if (lseek(fd, 0, SEEK_SET) != 0 || write(fd, mbr, secsz) != secsz) {
		free(mbr);
		return (errno);
	}
	free(mbr);
	return (0);
}

static struct mkimg_scheme mbr_scheme = {
	.name = "mbr",
	.description = "Master Boot Record",
	.aliases = mbr_aliases,
	.metadata = mbr_metadata,
	.write = mbr_write,
	.bootcode = 512,
	.nparts = NDOSPART
};

SCHEME_DEFINE(mbr_scheme);