Annotation of sys/msdosfs/bpb.h, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: bpb.h,v 1.5 2006/12/15 03:04:24 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: */
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: * 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 <machine/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: */
116: struct 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: */
134: struct 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: */
152: struct 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: */
177: struct 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: };
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