1/* $OpenBSD: bpb.h,v 1.7 2015/10/23 10:45:31 krw Exp $ */
2/* $NetBSD: bpb.h,v 1.6 1997/10/17 11:23:35 ws Exp $ */
3
4/*
5 * Written by Paul Popelka (paulp@uts.amdahl.com)
6 *
7 * You can do anything you want with this software, just don't say you wrote
8 * it, and don't remove this notice.
9 *
10 * This software is provided "as is".
11 *
12 * The author supplies this software to be publicly redistributed on the
13 * understanding that the author is not responsible for the correct
14 * functioning of this software in any circumstances and is not liable for
15 * any damages caused by this software.
16 *
17 * October 1992
18 */
19
20/*
21 * BIOS Parameter Block (BPB) for DOS 3.3
22 */
23struct bpb33 {
24 u_int16_t bpbBytesPerSec; /* bytes per sector */
25 u_int8_t bpbSecPerClust; /* sectors per cluster */
26 u_int16_t bpbResSectors; /* number of reserved sectors */
27 u_int8_t bpbFATs; /* number of FATs */
28 u_int16_t bpbRootDirEnts; /* number of root directory entries */
29 u_int16_t bpbSectors; /* total number of sectors */
30 u_int8_t bpbMedia; /* media descriptor */
31 u_int16_t bpbFATsecs; /* number of sectors per FAT */
32 u_int16_t bpbSecPerTrack; /* sectors per track */
33 u_int16_t bpbHeads; /* number of heads */
34 u_int16_t bpbHiddenSecs; /* number of hidden sectors */
35};
36
37/*
38 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
39 * and bpbHugeSectors is not in the 3.3 bpb.
40 */
41struct bpb50 {
42 u_int16_t bpbBytesPerSec; /* bytes per sector */
43 u_int8_t bpbSecPerClust; /* sectors per cluster */
44 u_int16_t bpbResSectors; /* number of reserved sectors */
45 u_int8_t bpbFATs; /* number of FATs */
46 u_int16_t bpbRootDirEnts; /* number of root directory entries */
47 u_int16_t bpbSectors; /* total number of sectors */
48 u_int8_t bpbMedia; /* media descriptor */
49 u_int16_t bpbFATsecs; /* number of sectors per FAT */
50 u_int16_t bpbSecPerTrack; /* sectors per track */
51 u_int16_t bpbHeads; /* number of heads */
52 u_int32_t bpbHiddenSecs; /* # of hidden sectors */
53 u_int32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
54};
55
56/*
57 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50.
58 */
59struct bpb710 {
60 u_int16_t bpbBytesPerSec; /* bytes per sector */
61 u_int8_t bpbSecPerClust; /* sectors per cluster */
62 u_int16_t bpbResSectors; /* number of reserved sectors */
63 u_int8_t bpbFATs; /* number of FATs */
64 u_int16_t bpbRootDirEnts; /* number of root directory entries */
65 u_int16_t bpbSectors; /* total number of sectors */
66 u_int8_t bpbMedia; /* media descriptor */
67 u_int16_t bpbFATsecs; /* number of sectors per FAT */
68 u_int16_t bpbSecPerTrack; /* sectors per track */
69 u_int16_t bpbHeads; /* number of heads */
70 u_int32_t bpbHiddenSecs; /* # of hidden sectors */
71 u_int32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
72 u_int32_t bpbBigFATsecs; /* like bpbFATsecs for FAT32 */
73 u_int16_t bpbExtFlags; /* extended flags: */
74#define FATNUM 0xf /* mask for numbering active FAT */
75#define FATMIRROR 0x80 /* FAT is mirrored (like it always was) */
76 u_int16_t bpbFSVers; /* filesystem version */
77#define FSVERS 0 /* currently only 0 is understood */
78 u_int32_t bpbRootClust; /* start cluster for root directory */
79 u_int16_t bpbFSInfo; /* filesystem info structure sector */
80 u_int16_t bpbBackup; /* backup boot sector */
81 /* There is a 12 byte filler here, but we ignore it */
82};
83
84/*
85 * The following structures represent how the bpb's look on disk. shorts
86 * and longs are just character arrays of the appropriate length. This is
87 * because the compiler forces shorts and longs to align on word or
88 * halfword boundaries.
89 *
90 * XXX The little-endian code here assumes that the processor can access
91 * 16-bit and 32-bit quantities on byte boundaries. If this is not true,
92 * use the macros for the big-endian case.
93 */
94#include <sys/endian.h>
95#if (BYTE_ORDER == LITTLE_ENDIAN) && !defined(__STRICT_ALIGNMENT)
96#define getushort(x) *((u_int16_t *)(x))
97#define getulong(x) *((u_int32_t *)(x))
98#define putushort(p, v) (*((u_int16_t *)(p)) = (v))
99#define putulong(p, v) (*((u_int32_t *)(p)) = (v))
100#else
101#define getushort(x) (((u_int8_t *)(x))[0] + (((u_int8_t *)(x))[1] << 8))
102#define getulong(x) (((u_int8_t *)(x))[0] + (((u_int8_t *)(x))[1] << 8) \
103 + (((u_int8_t *)(x))[2] << 16) \
104 + (((u_int8_t *)(x))[3] << 24))
105#define putushort(p, v) (((u_int8_t *)(p))[0] = (v), \
106 ((u_int8_t *)(p))[1] = (v) >> 8)
107#define putulong(p, v) (((u_int8_t *)(p))[0] = (v), \
108 ((u_int8_t *)(p))[1] = (v) >> 8, \
109 ((u_int8_t *)(p))[2] = (v) >> 16,\
110 ((u_int8_t *)(p))[3] = (v) >> 24)
111#endif
112
113/*
114 * BIOS Parameter Block (BPB) for DOS 3.3
115 */
116struct byte_bpb33 {
117 int8_t bpbBytesPerSec[2]; /* bytes per sector */
118 int8_t bpbSecPerClust; /* sectors per cluster */
119 int8_t bpbResSectors[2]; /* number of reserved sectors */
120 int8_t bpbFATs; /* number of FATs */
121 int8_t bpbRootDirEnts[2]; /* number of root directory entries */
122 int8_t bpbSectors[2]; /* total number of sectors */
123 int8_t bpbMedia; /* media descriptor */
124 int8_t bpbFATsecs[2]; /* number of sectors per FAT */
125 int8_t bpbSecPerTrack[2]; /* sectors per track */
126 int8_t bpbHeads[2]; /* number of heads */
127 int8_t bpbHiddenSecs[2]; /* number of hidden sectors */
128};
129
130/*
131 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
132 * and bpbHugeSectors is not in the 3.3 bpb.
133 */
134struct byte_bpb50 {
135 int8_t bpbBytesPerSec[2]; /* bytes per sector */
136 int8_t bpbSecPerClust; /* sectors per cluster */
137 int8_t bpbResSectors[2]; /* number of reserved sectors */
138 int8_t bpbFATs; /* number of FATs */
139 int8_t bpbRootDirEnts[2]; /* number of root directory entries */
140 int8_t bpbSectors[2]; /* total number of sectors */
141 int8_t bpbMedia; /* media descriptor */
142 int8_t bpbFATsecs[2]; /* number of sectors per FAT */
143 int8_t bpbSecPerTrack[2]; /* sectors per track */
144 int8_t bpbHeads[2]; /* number of heads */
145 int8_t bpbHiddenSecs[4]; /* number of hidden sectors */
146 int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */
147};
148
149/*
150 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50.
151 */
152struct byte_bpb710 {
153 u_int8_t bpbBytesPerSec[2]; /* bytes per sector */
154 u_int8_t bpbSecPerClust; /* sectors per cluster */
155 u_int8_t bpbResSectors[2]; /* number of reserved sectors */
156 u_int8_t bpbFATs; /* number of FATs */
157 u_int8_t bpbRootDirEnts[2]; /* number of root directory entries */
158 u_int8_t bpbSectors[2]; /* total number of sectors */
159 u_int8_t bpbMedia; /* media descriptor */
160 u_int8_t bpbFATsecs[2]; /* number of sectors per FAT */
161 u_int8_t bpbSecPerTrack[2]; /* sectors per track */
162 u_int8_t bpbHeads[2]; /* number of heads */
163 u_int8_t bpbHiddenSecs[4]; /* # of hidden sectors */
164 u_int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */
165 u_int8_t bpbBigFATsecs[4]; /* like bpbFATsecs for FAT32 */
166 u_int8_t bpbExtFlags[2]; /* extended flags: */
167 u_int8_t bpbFSVers[2]; /* filesystem version */
168 u_int8_t bpbRootClust[4]; /* start cluster for root directory */
169 u_int8_t bpbFSInfo[2]; /* filesystem info structure sector */
170 u_int8_t bpbBackup[2]; /* backup boot sector */
171 /* There is a 12 byte filler here, but we ignore it */
172};
173
174/*
175 * FAT32 FSInfo block.
176 */
177struct fsinfo {
178 u_int8_t fsisig1[4];
179 u_int8_t fsifill1[480];
180 u_int8_t fsisig2[4];
181 u_int8_t fsinfree[4];
182 u_int8_t fsinxtfree[4];
183 u_int8_t fsifill2[12];
184 u_int8_t fsisig3[4];
185 u_int8_t fsifill3[508];
186 u_int8_t fsisig4[4];
187};