FreeBSD/Linux Kernel Cross Reference
sys/fs/msdosfs/bpb.h
1 /* $FreeBSD: releng/8.0/sys/fs/msdosfs/bpb.h 171406 2007-07-12 16:09:07Z bde $ */
2 /* $NetBSD: bpb.h,v 1.7 1997/11/17 15:36:24 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 */
23 struct 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 */
41 struct 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 */
59 struct 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
91 #include <sys/endian.h>
92
93 #define getushort(x) le16dec(x)
94 #define getulong(x) le32dec(x)
95 #define putushort(p, v) le16enc(p, v)
96 #define putulong(p, v) le32enc(p, v)
97
98 /*
99 * BIOS Parameter Block (BPB) for DOS 3.3
100 */
101 struct byte_bpb33 {
102 int8_t bpbBytesPerSec[2]; /* bytes per sector */
103 int8_t bpbSecPerClust; /* sectors per cluster */
104 int8_t bpbResSectors[2]; /* number of reserved sectors */
105 int8_t bpbFATs; /* number of FATs */
106 int8_t bpbRootDirEnts[2]; /* number of root directory entries */
107 int8_t bpbSectors[2]; /* total number of sectors */
108 int8_t bpbMedia; /* media descriptor */
109 int8_t bpbFATsecs[2]; /* number of sectors per FAT */
110 int8_t bpbSecPerTrack[2]; /* sectors per track */
111 int8_t bpbHeads[2]; /* number of heads */
112 int8_t bpbHiddenSecs[2]; /* number of hidden sectors */
113 };
114
115 /*
116 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
117 * and bpbHugeSectors is not in the 3.3 bpb.
118 */
119 struct byte_bpb50 {
120 int8_t bpbBytesPerSec[2]; /* bytes per sector */
121 int8_t bpbSecPerClust; /* sectors per cluster */
122 int8_t bpbResSectors[2]; /* number of reserved sectors */
123 int8_t bpbFATs; /* number of FATs */
124 int8_t bpbRootDirEnts[2]; /* number of root directory entries */
125 int8_t bpbSectors[2]; /* total number of sectors */
126 int8_t bpbMedia; /* media descriptor */
127 int8_t bpbFATsecs[2]; /* number of sectors per FAT */
128 int8_t bpbSecPerTrack[2]; /* sectors per track */
129 int8_t bpbHeads[2]; /* number of heads */
130 int8_t bpbHiddenSecs[4]; /* number of hidden sectors */
131 int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */
132 };
133
134 /*
135 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50.
136 */
137 struct byte_bpb710 {
138 u_int8_t bpbBytesPerSec[2]; /* bytes per sector */
139 u_int8_t bpbSecPerClust; /* sectors per cluster */
140 u_int8_t bpbResSectors[2]; /* number of reserved sectors */
141 u_int8_t bpbFATs; /* number of FATs */
142 u_int8_t bpbRootDirEnts[2]; /* number of root directory entries */
143 u_int8_t bpbSectors[2]; /* total number of sectors */
144 u_int8_t bpbMedia; /* media descriptor */
145 u_int8_t bpbFATsecs[2]; /* number of sectors per FAT */
146 u_int8_t bpbSecPerTrack[2]; /* sectors per track */
147 u_int8_t bpbHeads[2]; /* number of heads */
148 u_int8_t bpbHiddenSecs[4]; /* # of hidden sectors */
149 u_int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */
150 u_int8_t bpbBigFATsecs[4]; /* like bpbFATsecs for FAT32 */
151 u_int8_t bpbExtFlags[2]; /* extended flags: */
152 u_int8_t bpbFSVers[2]; /* filesystem version */
153 u_int8_t bpbRootClust[4]; /* start cluster for root directory */
154 u_int8_t bpbFSInfo[2]; /* filesystem info structure sector */
155 u_int8_t bpbBackup[2]; /* backup boot sector */
156 /* There is a 12 byte filler here, but we ignore it */
157 };
158
159 /*
160 * FAT32 FSInfo block.
161 */
162 struct fsinfo {
163 u_int8_t fsisig1[4];
164 u_int8_t fsifill1[480];
165 u_int8_t fsisig2[4];
166 u_int8_t fsinfree[4];
167 u_int8_t fsinxtfree[4];
168 u_int8_t fsifill2[12];
169 u_int8_t fsisig3[4];
170 };
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