ebr.c revision 272776 
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: stable/10/usr.bin/mkimg/ebr.c 272776 2014-10-08 22:13:18Z 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 "image.h"
39#include "mkimg.h"
40#include "scheme.h"
41
42#ifndef DOSPTYP_FAT32
43#define	DOSPTYP_FAT32	0x0b
44#endif
45
46static struct mkimg_alias ebr_aliases[] = {
47    {	ALIAS_FAT32, ALIAS_INT2TYPE(DOSPTYP_FAT32) },
48    {	ALIAS_FREEBSD, ALIAS_INT2TYPE(DOSPTYP_386BSD) },
49    {	ALIAS_NONE, 0 }
50};
51
52static lba_t
53ebr_metadata(u_int where, lba_t blk)
54{
55
56	blk += (where == SCHEME_META_PART_BEFORE) ? 1 : 0;
57	return (round_track(blk));
58}
59
60static void
61ebr_chs(u_char *cylp, u_char *hdp, u_char *secp, lba_t lba)
62{
63	u_int cyl, hd, sec;
64
65	mkimg_chs(lba, 1023, &cyl, &hd, &sec);
66	*cylp = cyl;
67	*hdp = hd;
68	*secp = (sec & 0x3f) | ((cyl >> 2) & 0xc0);
69}
70
71static int
72ebr_write(lba_t imgsz __unused, void *bootcode __unused)
73{
74	u_char *ebr;
75	struct dos_partition *dp;
76	struct part *part, *next;
77	lba_t block, size;
78	int error;
79
80	ebr = malloc(secsz);
81	if (ebr == NULL)
82		return (ENOMEM);
83	memset(ebr, 0, secsz);
84	le16enc(ebr + DOSMAGICOFFSET, DOSMAGIC);
85
86	error = 0;
87	STAILQ_FOREACH_SAFE(part, &partlist, link, next) {
88		block = part->block - nsecs;
89		size = round_track(part->size);
90		dp = (void *)(ebr + DOSPARTOFF);
91		ebr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect, nsecs);
92		dp->dp_typ = ALIAS_TYPE2INT(part->type);
93		ebr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
94		    part->block + size - 1);
95		le32enc(&dp->dp_start, nsecs);
96		le32enc(&dp->dp_size, size);
97
98		/* Add link entry */
99		if (next != NULL) {
100			size = round_track(next->size);
101			dp++;
102			ebr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect,
103			    next->block - nsecs);
104			dp->dp_typ = DOSPTYP_EXT;
105			ebr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
106			    next->block + size - 1);
107			le32enc(&dp->dp_start, next->block - nsecs);
108			le32enc(&dp->dp_size, size + nsecs);
109		}
110
111		error = image_write(block, ebr, 1);
112		if (error)
113			break;
114
115		memset(ebr + DOSPARTOFF, 0, 2 * DOSPARTSIZE);
116	}
117
118	free(ebr);
119	return (error);
120}
121
122static struct mkimg_scheme ebr_scheme = {
123	.name = "ebr",
124	.description = "Extended Boot Record",
125	.aliases = ebr_aliases,
126	.metadata = ebr_metadata,
127	.write = ebr_write,
128	.nparts = 4096,
129	.maxsecsz = 4096
130};
131
132SCHEME_DEFINE(ebr_scheme);
133