FreeBSD/Linux Kernel Cross Reference
sys/msdosfs/bpb.h
1 /* $FreeBSD: src/sys/msdosfs/bpb.h,v 1.3.4.2 1999/09/05 08:17:15 peter Exp $ */
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 #ifdef atari
85 /*
86 * BPB for gemdos filesystems. Atari leaves the obsolete stuff undefined.
87 * Currently there is no need for a separate BPB structure.
88 */
89 #if 0
90 struct bpb_a {
91 u_int16_t bpbBytesPerSec; /* bytes per sector */
92 u_int8_t bpbSecPerClust; /* sectors per cluster */
93 u_int16_t bpbResSectors; /* number of reserved sectors */
94 u_int8_t bpbFATs; /* number of FATs */
95 u_int16_t bpbRootDirEnts; /* number of root directory entries */
96 u_int16_t bpbSectors; /* total number of sectors */
97 u_int8_t bpbUseless1; /* meaningless on gemdos fs */
98 u_int16_t bpbFATsecs; /* number of sectors per FAT */
99 u_int16_t bpbUseless2; /* meaningless for harddisk fs */
100 u_int16_t bpbUseless3; /* meaningless for harddisk fs */
101 u_int16_t bpbHiddenSecs; /* the TOS-BIOS ignores this */
102 };
103 #endif
104 #endif /* atari */
105
106 /*
107 * The following structures represent how the bpb's look on disk. shorts
108 * and longs are just character arrays of the appropriate length. This is
109 * because the compiler forces shorts and longs to align on word or
110 * halfword boundaries.
111 *
112 * XXX The little-endian code here assumes that the processor can access
113 * 16-bit and 32-bit quantities on byte boundaries. If this is not true,
114 * use the macros for the big-endian case.
115 */
116 #include <machine/endian.h>
117 #if (BYTE_ORDER == LITTLE_ENDIAN) /* && defined(UNALIGNED_ACCESS) */
118 #define getushort(x) *((u_int16_t *)(x))
119 #define getulong(x) *((u_int32_t *)(x))
120 #define putushort(p, v) (*((u_int16_t *)(p)) = (v))
121 #define putulong(p, v) (*((u_int32_t *)(p)) = (v))
122 #else
123 #define getushort(x) (((u_int8_t *)(x))[0] + (((u_int8_t *)(x))[1] << 8))
124 #define getulong(x) (((u_int8_t *)(x))[0] + (((u_int8_t *)(x))[1] << 8) \
125 + (((u_int8_t *)(x))[2] << 16) \
126 + (((u_int8_t *)(x))[3] << 24))
127 #define putushort(p, v) (((u_int8_t *)(p))[0] = (v), \
128 ((u_int8_t *)(p))[1] = (v) >> 8)
129 #define putulong(p, v) (((u_int8_t *)(p))[0] = (v), \
130 ((u_int8_t *)(p))[1] = (v) >> 8, \
131 ((u_int8_t *)(p))[2] = (v) >> 16,\
132 ((u_int8_t *)(p))[3] = (v) >> 24)
133 #endif
134
135 /*
136 * BIOS Parameter Block (BPB) for DOS 3.3
137 */
138 struct byte_bpb33 {
139 int8_t bpbBytesPerSec[2]; /* bytes per sector */
140 int8_t bpbSecPerClust; /* sectors per cluster */
141 int8_t bpbResSectors[2]; /* number of reserved sectors */
142 int8_t bpbFATs; /* number of FATs */
143 int8_t bpbRootDirEnts[2]; /* number of root directory entries */
144 int8_t bpbSectors[2]; /* total number of sectors */
145 int8_t bpbMedia; /* media descriptor */
146 int8_t bpbFATsecs[2]; /* number of sectors per FAT */
147 int8_t bpbSecPerTrack[2]; /* sectors per track */
148 int8_t bpbHeads[2]; /* number of heads */
149 int8_t bpbHiddenSecs[2]; /* number of hidden sectors */
150 };
151
152 /*
153 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
154 * and bpbHugeSectors is not in the 3.3 bpb.
155 */
156 struct byte_bpb50 {
157 int8_t bpbBytesPerSec[2]; /* bytes per sector */
158 int8_t bpbSecPerClust; /* sectors per cluster */
159 int8_t bpbResSectors[2]; /* number of reserved sectors */
160 int8_t bpbFATs; /* number of FATs */
161 int8_t bpbRootDirEnts[2]; /* number of root directory entries */
162 int8_t bpbSectors[2]; /* total number of sectors */
163 int8_t bpbMedia; /* media descriptor */
164 int8_t bpbFATsecs[2]; /* number of sectors per FAT */
165 int8_t bpbSecPerTrack[2]; /* sectors per track */
166 int8_t bpbHeads[2]; /* number of heads */
167 int8_t bpbHiddenSecs[4]; /* number of hidden sectors */
168 int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */
169 };
170
171 /*
172 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50.
173 */
174 struct byte_bpb710 {
175 u_int8_t bpbBytesPerSec[2]; /* bytes per sector */
176 u_int8_t bpbSecPerClust; /* sectors per cluster */
177 u_int8_t bpbResSectors[2]; /* number of reserved sectors */
178 u_int8_t bpbFATs; /* number of FATs */
179 u_int8_t bpbRootDirEnts[2]; /* number of root directory entries */
180 u_int8_t bpbSectors[2]; /* total number of sectors */
181 u_int8_t bpbMedia; /* media descriptor */
182 u_int8_t bpbFATsecs[2]; /* number of sectors per FAT */
183 u_int8_t bpbSecPerTrack[2]; /* sectors per track */
184 u_int8_t bpbHeads[2]; /* number of heads */
185 u_int8_t bpbHiddenSecs[4]; /* # of hidden sectors */
186 u_int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */
187 u_int8_t bpbBigFATsecs[4]; /* like bpbFATsecs for FAT32 */
188 u_int8_t bpbExtFlags[2]; /* extended flags: */
189 u_int8_t bpbFSVers[2]; /* filesystem version */
190 u_int8_t bpbRootClust[4]; /* start cluster for root directory */
191 u_int8_t bpbFSInfo[2]; /* filesystem info structure sector */
192 u_int8_t bpbBackup[2]; /* backup boot sector */
193 /* There is a 12 byte filler here, but we ignore it */
194 };
195
196 /*
197 * FAT32 FSInfo block.
198 */
199 struct fsinfo {
200 u_int8_t fsisig1[4];
201 u_int8_t fsifill1[480];
202 u_int8_t fsisig2[4];
203 u_int8_t fsinfree[4];
204 u_int8_t fsinxtfree[4];
205 u_int8_t fsifill2[12];
206 u_int8_t fsisig3[4];
207 u_int8_t fsifill3[508];
208 u_int8_t fsisig4[4];
209 };
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