1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2014 Juniper Networks, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include <sys/errno.h>
31 #include <stdint.h>
32 #include <stdlib.h>
33 #include <string.h>
34
35 #include <mbr.h>
36
37 #include "endian.h"
38 #include "image.h"
39 #include "mkimg.h"
40 #include "scheme.h"
41
42 static struct mkimg_alias mbr_aliases[] = {
43 { ALIAS_EBR, ALIAS_INT2TYPE(DOSPTYP_EXT) },
44 { ALIAS_EFI, ALIAS_INT2TYPE(DOSPTYP_EFI) },
45 { ALIAS_FAT16B, ALIAS_INT2TYPE(DOSPTYP_FAT16) },
46 { ALIAS_FAT32, ALIAS_INT2TYPE(DOSPTYP_FAT32) },
47 { ALIAS_FAT32LBA, ALIAS_INT2TYPE(DOSPTYP_FAT32LBA) },
48 { ALIAS_FREEBSD, ALIAS_INT2TYPE(DOSPTYP_386BSD) },
49 { ALIAS_NTFS, ALIAS_INT2TYPE(DOSPTYP_NTFS) },
50 { ALIAS_PPCBOOT, ALIAS_INT2TYPE(DOSPTYP_PPCBOOT) },
51 { ALIAS_NONE, 0 } /* Keep last! */
52 };
53
54 static lba_t
mbr_metadata(u_int where,lba_t blk)55 mbr_metadata(u_int where, lba_t blk)
56 {
57
58 blk += (where == SCHEME_META_IMG_START) ? 1 : 0;
59 return (round_track(blk));
60 }
61
62 static void
mbr_chs(u_char * cylp,u_char * hdp,u_char * secp,lba_t lba)63 mbr_chs(u_char *cylp, u_char *hdp, u_char *secp, lba_t lba)
64 {
65 u_int cyl, hd, sec;
66
67 mkimg_chs(lba, 1023, &cyl, &hd, &sec);
68 *cylp = cyl;
69 *hdp = hd;
70 *secp = (sec & 0x3f) | ((cyl >> 2) & 0xc0);
71 }
72
73 static int
mbr_write(lba_t imgsz __unused,void * bootcode)74 mbr_write(lba_t imgsz __unused, void *bootcode)
75 {
76 u_char *mbr;
77 struct dos_partition *dpbase, *dp;
78 struct part *part;
79 lba_t size;
80 int error;
81
82 mbr = malloc(secsz);
83 if (mbr == NULL)
84 return (ENOMEM);
85 if (bootcode != NULL) {
86 memcpy(mbr, bootcode, DOSPARTOFF);
87 memset(mbr + DOSPARTOFF, 0, secsz - DOSPARTOFF);
88 } else
89 memset(mbr, 0, secsz);
90 le16enc(mbr + DOSMAGICOFFSET, DOSMAGIC);
91 dpbase = (void *)(mbr + DOSPARTOFF);
92 TAILQ_FOREACH(part, &partlist, link) {
93 size = round_track(part->size);
94 dp = dpbase + part->index;
95 if (active_partition != 0)
96 dp->dp_flag =
97 (part->index + 1 == active_partition) ? 0x80 : 0;
98 else
99 dp->dp_flag =
100 (part->index == 0 && bootcode != NULL) ? 0x80 : 0;
101 mbr_chs(&dp->dp_scyl, &dp->dp_shd, &dp->dp_ssect,
102 part->block);
103 dp->dp_typ = ALIAS_TYPE2INT(part->type);
104 mbr_chs(&dp->dp_ecyl, &dp->dp_ehd, &dp->dp_esect,
105 part->block + size - 1);
106 le32enc(&dp->dp_start, part->block);
107 le32enc(&dp->dp_size, size);
108 }
109 error = image_write(0, mbr, 1);
110 free(mbr);
111 return (error);
112 }
113
114 static struct mkimg_scheme mbr_scheme = {
115 .name = "mbr",
116 .description = "Master Boot Record",
117 .aliases = mbr_aliases,
118 .metadata = mbr_metadata,
119 .write = mbr_write,
120 .bootcode = 512,
121 .nparts = NDOSPART,
122 .maxsecsz = 4096
123 };
124
125 SCHEME_DEFINE(mbr_scheme);
126