ebr.c revision 263674 
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/ebr.c 263674 2014-03-23 20:17:38Z 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 ebr_aliases[] = {
42    {	ALIAS_FAT32, ALIAS_INT2TYPE(DOSPTYP_FAT32) },
43    {	ALIAS_FREEBSD, ALIAS_INT2TYPE(DOSPTYP_386BSD) },
44    {	ALIAS_NONE, 0 }
45};
46
47static u_int
48ebr_metadata(u_int where)
49{
50	u_int secs;
51
52	secs = (where == SCHEME_META_PART_BEFORE) ? 1 : 0;
53	return (secs);
54}
55
56static void
57ebr_chs(u_char *cyl, u_char *hd, u_char *sec, uint32_t lba __unused)
58{
59
60	*cyl = 0xff;		/* XXX */
61	*hd = 0xff;		/* XXX */
62	*sec = 0xff;		/* XXX */
63}
64
65static int
66ebr_write(int fd, lba_t imgsz __unused, void *bootcode __unused)
67{
68	u_char *ebr;
69	struct dos_partition *dp;
70	struct part *part, *next;
71	lba_t block, trksz;
72	int error;
73
74	ebr = malloc(secsz);
75	if (ebr == NULL)
76		return (ENOMEM);
77	memset(ebr, 0, secsz);
78	le16enc(ebr + DOSMAGICOFFSET, DOSMAGIC);
79
80	error = 0;
81	trksz = 1;	/* Sectors/track */
82	STAILQ_FOREACH_SAFE(part, &partlist, link, next) {
83		block = part->block - trksz;
84		dp = (void *)(ebr + DOSPARTOFF);
85		ebr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect, trksz);
86		dp->dp_typ = ALIAS_TYPE2INT(part->type);
87		ebr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
88		    part->block + part->size - 1);
89		le32enc(&dp->dp_start, trksz);
90		le32enc(&dp->dp_size, part->size);
91
92		/* Add link entry */
93		if (next != NULL) {
94			dp++;
95			ebr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect,
96			    next->block - trksz);
97			dp->dp_typ = DOSPTYP_EXT;
98			ebr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
99			    next->block + next->size - 1);
100			le32enc(&dp->dp_start, next->block - trksz);
101			le32enc(&dp->dp_size, next->size + trksz);
102		}
103
104		error = mkimg_seek(fd, block);
105		if (error == 0) {
106			if (write(fd, ebr, secsz) != secsz)
107				error = errno;
108		}
109		if (error)
110			break;
111
112		memset(ebr + DOSPARTOFF, 0, 2 * DOSPARTSIZE);
113	}
114
115	free(ebr);
116	return (error);
117}
118
119static struct mkimg_scheme ebr_scheme = {
120	.name = "ebr",
121	.description = "Extended Boot Record",
122	.aliases = ebr_aliases,
123	.metadata = ebr_metadata,
124	.write = ebr_write,
125	.nparts = 4096
126};
127
128SCHEME_DEFINE(ebr_scheme);
129