xref: /freebsd/usr.bin/mkimg/ebr.c (revision 38f0b757fd84d17d0fc24739a7cda160c4516d81)
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 "mkimg.h"
39 #include "scheme.h"
40 
41 #ifndef DOSPTYP_FAT32
42 #define	DOSPTYP_FAT32	0x0b
43 #endif
44 
45 static struct mkimg_alias ebr_aliases[] = {
46     {	ALIAS_FAT32, ALIAS_INT2TYPE(DOSPTYP_FAT32) },
47     {	ALIAS_FREEBSD, ALIAS_INT2TYPE(DOSPTYP_386BSD) },
48     {	ALIAS_NONE, 0 }
49 };
50 
51 static u_int
52 ebr_metadata(u_int where)
53 {
54 	u_int secs;
55 
56 	secs = (where == SCHEME_META_PART_BEFORE) ? nsecs : 0;
57 	return (secs);
58 }
59 
60 static void
61 ebr_chs(u_char *cyl, u_char *hd, u_char *sec, uint32_t lba __unused)
62 {
63 
64 	*cyl = 0xff;		/* XXX */
65 	*hd = 0xff;		/* XXX */
66 	*sec = 0xff;		/* XXX */
67 }
68 
69 static int
70 ebr_write(int fd, lba_t imgsz __unused, void *bootcode __unused)
71 {
72 	u_char *ebr;
73 	struct dos_partition *dp;
74 	struct part *part, *next;
75 	lba_t block;
76 	int error;
77 
78 	ebr = malloc(secsz);
79 	if (ebr == NULL)
80 		return (ENOMEM);
81 	memset(ebr, 0, secsz);
82 	le16enc(ebr + DOSMAGICOFFSET, DOSMAGIC);
83 
84 	error = 0;
85 	STAILQ_FOREACH_SAFE(part, &partlist, link, next) {
86 		block = part->block - nsecs;
87 		dp = (void *)(ebr + DOSPARTOFF);
88 		ebr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect, nsecs);
89 		dp->dp_typ = ALIAS_TYPE2INT(part->type);
90 		ebr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
91 		    part->block + part->size - 1);
92 		le32enc(&dp->dp_start, nsecs);
93 		le32enc(&dp->dp_size, part->size);
94 
95 		/* Add link entry */
96 		if (next != NULL) {
97 			dp++;
98 			ebr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect,
99 			    next->block - nsecs);
100 			dp->dp_typ = DOSPTYP_EXT;
101 			ebr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
102 			    next->block + next->size - 1);
103 			le32enc(&dp->dp_start, next->block - nsecs);
104 			le32enc(&dp->dp_size, next->size + nsecs);
105 		}
106 
107 		error = mkimg_seek(fd, block);
108 		if (error == 0) {
109 			if (write(fd, ebr, secsz) != (ssize_t)secsz)
110 				error = errno;
111 		}
112 		if (error)
113 			break;
114 
115 		memset(ebr + DOSPARTOFF, 0, 2 * DOSPARTSIZE);
116 	}
117 
118 	free(ebr);
119 	return (error);
120 }
121 
122 static 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 
132 SCHEME_DEFINE(ebr_scheme);
133