master
1/* $NetBSD: bpb.h,v 1.7 1997/11/17 15:36:24 ws Exp $ */
2
3/*-
4 * Written by Paul Popelka (paulp@uts.amdahl.com)
5 *
6 * You can do anything you want with this software, just don't say you wrote
7 * it, and don't remove this notice.
8 *
9 * This software is provided "as is".
10 *
11 * The author supplies this software to be publicly redistributed on the
12 * understanding that the author is not responsible for the correct
13 * functioning of this software in any circumstances and is not liable for
14 * any damages caused by this software.
15 *
16 * October 1992
17 */
18
19#ifndef _FS_MSDOSFS_BPB_H_
20#define _FS_MSDOSFS_BPB_H_
21
22/*
23 * BIOS Parameter Block (BPB) for DOS 3.3
24 */
25struct bpb33 {
26 uint16_t bpbBytesPerSec; /* bytes per sector */
27 uint8_t bpbSecPerClust; /* sectors per cluster */
28 uint16_t bpbResSectors; /* number of reserved sectors */
29 uint8_t bpbFATs; /* number of FATs */
30 uint16_t bpbRootDirEnts; /* number of root directory entries */
31 uint16_t bpbSectors; /* total number of sectors */
32 uint8_t bpbMedia; /* media descriptor */
33 uint16_t bpbFATsecs; /* number of sectors per FAT */
34 uint16_t bpbSecPerTrack; /* sectors per track */
35 uint16_t bpbHeads; /* number of heads */
36 uint16_t bpbHiddenSecs; /* number of hidden sectors */
37};
38
39/*
40 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
41 * and bpbHugeSectors is not in the 3.3 bpb.
42 */
43struct bpb50 {
44 uint16_t bpbBytesPerSec; /* bytes per sector */
45 uint8_t bpbSecPerClust; /* sectors per cluster */
46 uint16_t bpbResSectors; /* number of reserved sectors */
47 uint8_t bpbFATs; /* number of FATs */
48 uint16_t bpbRootDirEnts; /* number of root directory entries */
49 uint16_t bpbSectors; /* total number of sectors */
50 uint8_t bpbMedia; /* media descriptor */
51 uint16_t bpbFATsecs; /* number of sectors per FAT */
52 uint16_t bpbSecPerTrack; /* sectors per track */
53 uint16_t bpbHeads; /* number of heads */
54 uint32_t bpbHiddenSecs; /* # of hidden sectors */
55 uint32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
56};
57
58/*
59 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50.
60 */
61struct bpb710 {
62 uint16_t bpbBytesPerSec; /* bytes per sector */
63 uint8_t bpbSecPerClust; /* sectors per cluster */
64 uint16_t bpbResSectors; /* number of reserved sectors */
65 uint8_t bpbFATs; /* number of FATs */
66 uint16_t bpbRootDirEnts; /* number of root directory entries */
67 uint16_t bpbSectors; /* total number of sectors */
68 uint8_t bpbMedia; /* media descriptor */
69 uint16_t bpbFATsecs; /* number of sectors per FAT */
70 uint16_t bpbSecPerTrack; /* sectors per track */
71 uint16_t bpbHeads; /* number of heads */
72 uint32_t bpbHiddenSecs; /* # of hidden sectors */
73 uint32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
74 uint32_t bpbBigFATsecs; /* like bpbFATsecs for FAT32 */
75 uint16_t bpbExtFlags; /* extended flags: */
76#define FATNUM 0xf /* mask for numbering active FAT */
77#define FATMIRROR 0x80 /* FAT is mirrored (like it always was) */
78 uint16_t bpbFSVers; /* filesystem version */
79#define FSVERS 0 /* currently only 0 is understood */
80 uint32_t bpbRootClust; /* start cluster for root directory */
81 uint16_t bpbFSInfo; /* filesystem info structure sector */
82 uint16_t bpbBackup; /* backup boot sector */
83 uint8_t bpbReserved[12]; /* reserved for future expansion */
84};
85
86/*
87 * The following structures represent how the bpb's look on disk. shorts
88 * and longs are just character arrays of the appropriate length. This is
89 * because the compiler forces shorts and longs to align on word or
90 * halfword boundaries.
91 */
92
93#include <sys/endian.h>
94
95#define getushort(x) le16dec(x)
96#define getulong(x) le32dec(x)
97#define putushort(p, v) le16enc(p, v)
98#define putulong(p, v) le32enc(p, v)
99
100/*
101 * BIOS Parameter Block (BPB) for DOS 3.3
102 */
103struct byte_bpb33 {
104 int8_t bpbBytesPerSec[2]; /* bytes per sector */
105 int8_t bpbSecPerClust; /* sectors per cluster */
106 int8_t bpbResSectors[2]; /* number of reserved sectors */
107 int8_t bpbFATs; /* number of FATs */
108 int8_t bpbRootDirEnts[2]; /* number of root directory entries */
109 int8_t bpbSectors[2]; /* total number of sectors */
110 int8_t bpbMedia; /* media descriptor */
111 int8_t bpbFATsecs[2]; /* number of sectors per FAT */
112 int8_t bpbSecPerTrack[2]; /* sectors per track */
113 int8_t bpbHeads[2]; /* number of heads */
114 int8_t bpbHiddenSecs[2]; /* number of hidden sectors */
115};
116
117/*
118 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
119 * and bpbHugeSectors is not in the 3.3 bpb.
120 */
121struct byte_bpb50 {
122 int8_t bpbBytesPerSec[2]; /* bytes per sector */
123 int8_t bpbSecPerClust; /* sectors per cluster */
124 int8_t bpbResSectors[2]; /* number of reserved sectors */
125 int8_t bpbFATs; /* number of FATs */
126 int8_t bpbRootDirEnts[2]; /* number of root directory entries */
127 int8_t bpbSectors[2]; /* total number of sectors */
128 int8_t bpbMedia; /* media descriptor */
129 int8_t bpbFATsecs[2]; /* number of sectors per FAT */
130 int8_t bpbSecPerTrack[2]; /* sectors per track */
131 int8_t bpbHeads[2]; /* number of heads */
132 int8_t bpbHiddenSecs[4]; /* number of hidden sectors */
133 int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */
134};
135
136/*
137 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50.
138 */
139struct byte_bpb710 {
140 uint8_t bpbBytesPerSec[2]; /* bytes per sector */
141 uint8_t bpbSecPerClust; /* sectors per cluster */
142 uint8_t bpbResSectors[2]; /* number of reserved sectors */
143 uint8_t bpbFATs; /* number of FATs */
144 uint8_t bpbRootDirEnts[2]; /* number of root directory entries */
145 uint8_t bpbSectors[2]; /* total number of sectors */
146 uint8_t bpbMedia; /* media descriptor */
147 uint8_t bpbFATsecs[2]; /* number of sectors per FAT */
148 uint8_t bpbSecPerTrack[2]; /* sectors per track */
149 uint8_t bpbHeads[2]; /* number of heads */
150 uint8_t bpbHiddenSecs[4]; /* # of hidden sectors */
151 uint8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */
152 uint8_t bpbBigFATsecs[4]; /* like bpbFATsecs for FAT32 */
153 uint8_t bpbExtFlags[2]; /* extended flags: */
154 uint8_t bpbFSVers[2]; /* filesystem version */
155 uint8_t bpbRootClust[4]; /* start cluster for root directory */
156 uint8_t bpbFSInfo[2]; /* filesystem info structure sector */
157 uint8_t bpbBackup[2]; /* backup boot sector */
158 uint8_t bpbReserved[12]; /* reserved for future expansion */
159};
160
161/*
162 * FAT32 FSInfo block.
163 */
164struct fsinfo {
165 uint8_t fsisig1[4];
166 uint8_t fsifill1[480];
167 uint8_t fsisig2[4];
168 uint8_t fsinfree[4];
169 uint8_t fsinxtfree[4];
170 uint8_t fsifill2[12];
171 uint8_t fsisig3[4];
172};
173#endif /* !_FS_MSDOSFS_BPB_H_ */