ebr.c revision 329059 
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/11/usr.bin/mkimg/ebr.c 329059 2018-02-09 09:15:43Z manu $");
29
30#include <sys/errno.h>
31#include <stdint.h>
32#include <stdlib.h>
33#include <string.h>
34#include <unistd.h>
35
36#include <sys/diskmbr.h>
37
38#include "endian.h"
39#include "image.h"
40#include "mkimg.h"
41#include "scheme.h"
42
43#ifndef DOSPTYP_FAT16B
44#define	DOSPTYP_FAT16B	0x06
45#endif
46#ifndef DOSPTYP_FAT32
47#define	DOSPTYP_FAT32	0x0b
48#endif
49
50static struct mkimg_alias ebr_aliases[] = {
51    {	ALIAS_FAT16B, ALIAS_INT2TYPE(DOSPTYP_FAT16B) },
52    {	ALIAS_FAT32, ALIAS_INT2TYPE(DOSPTYP_FAT32) },
53    {	ALIAS_FREEBSD, ALIAS_INT2TYPE(DOSPTYP_386BSD) },
54    {	ALIAS_NONE, 0 }
55};
56
57static lba_t
58ebr_metadata(u_int where, lba_t blk)
59{
60
61	blk += (where == SCHEME_META_PART_BEFORE) ? 1 : 0;
62	return (round_track(blk));
63}
64
65static void
66ebr_chs(u_char *cylp, u_char *hdp, u_char *secp, lba_t lba)
67{
68	u_int cyl, hd, sec;
69
70	mkimg_chs(lba, 1023, &cyl, &hd, &sec);
71	*cylp = cyl;
72	*hdp = hd;
73	*secp = (sec & 0x3f) | ((cyl >> 2) & 0xc0);
74}
75
76static int
77ebr_write(lba_t imgsz __unused, void *bootcode __unused)
78{
79	u_char *ebr;
80	struct dos_partition *dp;
81	struct part *part, *next;
82	lba_t block, size;
83	int error;
84
85	ebr = malloc(secsz);
86	if (ebr == NULL)
87		return (ENOMEM);
88	memset(ebr, 0, secsz);
89	le16enc(ebr + DOSMAGICOFFSET, DOSMAGIC);
90
91	error = 0;
92	TAILQ_FOREACH(part, &partlist, link) {
93		block = part->block - nsecs;
94		size = round_track(part->size);
95		dp = (void *)(ebr + DOSPARTOFF);
96		ebr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect, nsecs);
97		dp->dp_typ = ALIAS_TYPE2INT(part->type);
98		ebr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
99		    part->block + size - 1);
100		le32enc(&dp->dp_start, nsecs);
101		le32enc(&dp->dp_size, size);
102
103		/* Add link entry */
104		next = TAILQ_NEXT(part, link);
105		if (next != NULL) {
106			size = round_track(next->size);
107			dp++;
108			ebr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect,
109			    next->block - nsecs);
110			dp->dp_typ = DOSPTYP_EXT;
111			ebr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
112			    next->block + size - 1);
113			le32enc(&dp->dp_start, next->block - nsecs);
114			le32enc(&dp->dp_size, size + nsecs);
115		}
116
117		error = image_write(block, ebr, 1);
118		if (error)
119			break;
120
121		memset(ebr + DOSPARTOFF, 0, 2 * DOSPARTSIZE);
122	}
123
124	free(ebr);
125	return (error);
126}
127
128static struct mkimg_scheme ebr_scheme = {
129	.name = "ebr",
130	.description = "Extended Boot Record",
131	.aliases = ebr_aliases,
132	.metadata = ebr_metadata,
133	.write = ebr_write,
134	.nparts = 4096,
135	.maxsecsz = 4096
136};
137
138SCHEME_DEFINE(ebr_scheme);
139