mbr.c revision 263896 
1/*-
2 * Copyright (c) 2014 Juniper Networks, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: user/marcel/mkimg/mbr.c 263896 2014-03-29 03:46:36Z marcel $");
29
30#include <sys/types.h>
31#include <sys/diskmbr.h>
32#include <sys/endian.h>
33#include <sys/errno.h>
34#include <stdlib.h>
35#include <string.h>
36#include <unistd.h>
37
38#include "mkimg.h"
39#include "scheme.h"
40
41static struct mkimg_alias mbr_aliases[] = {
42    {	ALIAS_EBR, ALIAS_INT2TYPE(DOSPTYP_EXT) },
43    {	ALIAS_FAT32, ALIAS_INT2TYPE(DOSPTYP_FAT32) },
44    {	ALIAS_FREEBSD, ALIAS_INT2TYPE(DOSPTYP_386BSD) },
45    {	ALIAS_NONE, 0 }		/* Keep last! */
46};
47
48static u_int
49mbr_metadata(u_int where)
50{
51	u_int secs;
52
53	secs = (where == SCHEME_META_IMG_START) ? nsecs : 0;
54	return (secs);
55}
56
57static void
58mbr_chs(u_char *cyl, u_char *hd, u_char *sec, uint32_t lba __unused)
59{
60
61	*cyl = 0xff;		/* XXX */
62	*hd = 0xff;		/* XXX */
63	*sec = 0xff;		/* XXX */
64}
65
66static int
67mbr_write(int fd, lba_t imgsz __unused, void *bootcode)
68{
69	u_char *mbr;
70	struct dos_partition *dpbase, *dp;
71	struct part *part;
72	int error;
73
74	mbr = malloc(secsz);
75	if (mbr == NULL)
76		return (ENOMEM);
77	if (bootcode != NULL) {
78		memcpy(mbr, bootcode, DOSPARTOFF);
79		memset(mbr + DOSPARTOFF, 0, secsz - DOSPARTOFF);
80	} else
81		memset(mbr, 0, secsz);
82	le16enc(mbr + DOSMAGICOFFSET, DOSMAGIC);
83	dpbase = (void *)(mbr + DOSPARTOFF);
84	STAILQ_FOREACH(part, &partlist, link) {
85		dp = dpbase + part->index;
86		dp->dp_flag = (part->index == 0 && bootcode != NULL) ? 0x80 : 0;
87		mbr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect,
88		    part->block);
89		dp->dp_typ = ALIAS_TYPE2INT(part->type);
90		mbr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
91		    part->block + part->size - 1);
92		le32enc(&dp->dp_start, part->block);
93		le32enc(&dp->dp_size, part->size);
94	}
95	error = mkimg_seek(fd, 0);
96	if (error == 0) {
97		if (write(fd, mbr, secsz) != (ssize_t)secsz)
98			error = errno;
99	}
100	free(mbr);
101	return (error);
102}
103
104static struct mkimg_scheme mbr_scheme = {
105	.name = "mbr",
106	.description = "Master Boot Record",
107	.aliases = mbr_aliases,
108	.metadata = mbr_metadata,
109	.write = mbr_write,
110	.bootcode = 512,
111	.nparts = NDOSPART,
112	.maxsecsz = 4096
113};
114
115SCHEME_DEFINE(mbr_scheme);
116