xref: /freebsd/usr.bin/mkimg/mbr.c (revision f02f7422801bb39f5eaab8fc383fa7b70c467ff9)
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("$FreeBSD$");
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 "image.h"
39 #include "mkimg.h"
40 #include "scheme.h"
41 
42 #ifndef DOSPTYP_FAT32
43 #define	DOSPTYP_FAT32	0x0b
44 #endif
45 
46 static struct mkimg_alias mbr_aliases[] = {
47     {	ALIAS_EBR, ALIAS_INT2TYPE(DOSPTYP_EXT) },
48     {	ALIAS_FAT32, ALIAS_INT2TYPE(DOSPTYP_FAT32) },
49     {	ALIAS_FREEBSD, ALIAS_INT2TYPE(DOSPTYP_386BSD) },
50     {	ALIAS_NONE, 0 }		/* Keep last! */
51 };
52 
53 static lba_t
54 mbr_metadata(u_int where, lba_t blk)
55 {
56 
57 	blk += (where == SCHEME_META_IMG_START) ? 1 : 0;
58 	return (round_track(blk));
59 }
60 
61 static void
62 mbr_chs(u_char *cyl, u_char *hd, u_char *sec, uint32_t lba __unused)
63 {
64 
65 	*cyl = 0xff;		/* XXX */
66 	*hd = 0xff;		/* XXX */
67 	*sec = 0xff;		/* XXX */
68 }
69 
70 static int
71 mbr_write(lba_t imgsz __unused, void *bootcode)
72 {
73 	u_char *mbr;
74 	struct dos_partition *dpbase, *dp;
75 	struct part *part;
76 	int error;
77 
78 	mbr = malloc(secsz);
79 	if (mbr == NULL)
80 		return (ENOMEM);
81 	if (bootcode != NULL) {
82 		memcpy(mbr, bootcode, DOSPARTOFF);
83 		memset(mbr + DOSPARTOFF, 0, secsz - DOSPARTOFF);
84 	} else
85 		memset(mbr, 0, secsz);
86 	le16enc(mbr + DOSMAGICOFFSET, DOSMAGIC);
87 	dpbase = (void *)(mbr + DOSPARTOFF);
88 	STAILQ_FOREACH(part, &partlist, link) {
89 		dp = dpbase + part->index;
90 		dp->dp_flag = (part->index == 0 && bootcode != NULL) ? 0x80 : 0;
91 		mbr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect,
92 		    part->block);
93 		dp->dp_typ = ALIAS_TYPE2INT(part->type);
94 		mbr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
95 		    part->block + part->size - 1);
96 		le32enc(&dp->dp_start, part->block);
97 		le32enc(&dp->dp_size, part->size);
98 	}
99 	error = image_write(0, mbr, 1);
100 	free(mbr);
101 	return (error);
102 }
103 
104 static 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 
115 SCHEME_DEFINE(mbr_scheme);
116