xref: /freebsd/usr.bin/mkimg/ebr.c (revision 1834282de6b9f6fd30291bfe1cc9c3ecf5547c40)
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/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 
50 static 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 
57 static lba_t
58 ebr_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 
65 static void
66 ebr_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 
76 static int
77 ebr_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 
128 static 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 
138 SCHEME_DEFINE(ebr_scheme);
139