1 /* $FreeBSD: src/sys/msdosfs/bpb.h,v 1.7.2.1 2000/10/27 09:45:07 bde Exp $ */ 2 /* $DragonFly: src/sys/vfs/msdosfs/bpb.h,v 1.2 2003/06/17 04:28:47 dillon Exp $ */ 3 /* $NetBSD: bpb.h,v 1.7 1997/11/17 15:36:24 ws Exp $ */ 4 5 /* 6 * Written by Paul Popelka (paulp@uts.amdahl.com) 7 * 8 * You can do anything you want with this software, just don't say you wrote 9 * it, and don't remove this notice. 10 * 11 * This software is provided "as is". 12 * 13 * The author supplies this software to be publicly redistributed on the 14 * understanding that the author is not responsible for the correct 15 * functioning of this software in any circumstances and is not liable for 16 * any damages caused by this software. 17 * 18 * October 1992 19 */ 20 21 /* 22 * BIOS Parameter Block (BPB) for DOS 3.3 23 */ 24 struct bpb33 { 25 u_int16_t bpbBytesPerSec; /* bytes per sector */ 26 u_int8_t bpbSecPerClust; /* sectors per cluster */ 27 u_int16_t bpbResSectors; /* number of reserved sectors */ 28 u_int8_t bpbFATs; /* number of FATs */ 29 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 30 u_int16_t bpbSectors; /* total number of sectors */ 31 u_int8_t bpbMedia; /* media descriptor */ 32 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 33 u_int16_t bpbSecPerTrack; /* sectors per track */ 34 u_int16_t bpbHeads; /* number of heads */ 35 u_int16_t bpbHiddenSecs; /* number of hidden sectors */ 36 }; 37 38 /* 39 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3, 40 * and bpbHugeSectors is not in the 3.3 bpb. 41 */ 42 struct bpb50 { 43 u_int16_t bpbBytesPerSec; /* bytes per sector */ 44 u_int8_t bpbSecPerClust; /* sectors per cluster */ 45 u_int16_t bpbResSectors; /* number of reserved sectors */ 46 u_int8_t bpbFATs; /* number of FATs */ 47 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 48 u_int16_t bpbSectors; /* total number of sectors */ 49 u_int8_t bpbMedia; /* media descriptor */ 50 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 51 u_int16_t bpbSecPerTrack; /* sectors per track */ 52 u_int16_t bpbHeads; /* number of heads */ 53 u_int32_t bpbHiddenSecs; /* # of hidden sectors */ 54 u_int32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */ 55 }; 56 57 /* 58 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50. 59 */ 60 struct bpb710 { 61 u_int16_t bpbBytesPerSec; /* bytes per sector */ 62 u_int8_t bpbSecPerClust; /* sectors per cluster */ 63 u_int16_t bpbResSectors; /* number of reserved sectors */ 64 u_int8_t bpbFATs; /* number of FATs */ 65 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 66 u_int16_t bpbSectors; /* total number of sectors */ 67 u_int8_t bpbMedia; /* media descriptor */ 68 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 69 u_int16_t bpbSecPerTrack; /* sectors per track */ 70 u_int16_t bpbHeads; /* number of heads */ 71 u_int32_t bpbHiddenSecs; /* # of hidden sectors */ 72 u_int32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */ 73 u_int32_t bpbBigFATsecs; /* like bpbFATsecs for FAT32 */ 74 u_int16_t bpbExtFlags; /* extended flags: */ 75 #define FATNUM 0xf /* mask for numbering active FAT */ 76 #define FATMIRROR 0x80 /* FAT is mirrored (like it always was) */ 77 u_int16_t bpbFSVers; /* filesystem version */ 78 #define FSVERS 0 /* currently only 0 is understood */ 79 u_int32_t bpbRootClust; /* start cluster for root directory */ 80 u_int16_t bpbFSInfo; /* filesystem info structure sector */ 81 u_int16_t bpbBackup; /* backup boot sector */ 82 /* There is a 12 byte filler here, but we ignore it */ 83 }; 84 85 #ifdef atari 86 /* 87 * BPB for gemdos filesystems. Atari leaves the obsolete stuff undefined. 88 * Currently there is no need for a separate BPB structure. 89 */ 90 #if 0 91 struct bpb_a { 92 u_int16_t bpbBytesPerSec; /* bytes per sector */ 93 u_int8_t bpbSecPerClust; /* sectors per cluster */ 94 u_int16_t bpbResSectors; /* number of reserved sectors */ 95 u_int8_t bpbFATs; /* number of FATs */ 96 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 97 u_int16_t bpbSectors; /* total number of sectors */ 98 u_int8_t bpbUseless1; /* meaningless on gemdos fs */ 99 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 100 u_int16_t bpbUseless2; /* meaningless for harddisk fs */ 101 u_int16_t bpbUseless3; /* meaningless for harddisk fs */ 102 u_int16_t bpbHiddenSecs; /* the TOS-BIOS ignores this */ 103 }; 104 #endif 105 #endif /* atari */ 106 107 /* 108 * The following structures represent how the bpb's look on disk. shorts 109 * and longs are just character arrays of the appropriate length. This is 110 * because the compiler forces shorts and longs to align on word or 111 * halfword boundaries. 112 * 113 * XXX The little-endian code here assumes that the processor can access 114 * 16-bit and 32-bit quantities on byte boundaries. If this is not true, 115 * use the macros for the big-endian case. 116 */ 117 118 #include <machine/endian.h> 119 120 #ifdef __i386__ 121 #define UNLALIGNED_ACCESS 122 #endif 123 124 #if (BYTE_ORDER == LITTLE_ENDIAN) && defined(UNALIGNED_ACCESS) 125 #define getushort(x) *((u_int16_t *)(x)) 126 #define getulong(x) *((u_int32_t *)(x)) 127 #define putushort(p, v) (*((u_int16_t *)(p)) = (v)) 128 #define putulong(p, v) (*((u_int32_t *)(p)) = (v)) 129 #else 130 #define getushort(x) (((u_int8_t *)(x))[0] + (((u_int8_t *)(x))[1] << 8)) 131 #define getulong(x) (((u_int8_t *)(x))[0] + (((u_int8_t *)(x))[1] << 8) \ 132 + (((u_int8_t *)(x))[2] << 16) \ 133 + (((u_int8_t *)(x))[3] << 24)) 134 #define putushort(p, v) (((u_int8_t *)(p))[0] = (v), \ 135 ((u_int8_t *)(p))[1] = (v) >> 8) 136 #define putulong(p, v) (((u_int8_t *)(p))[0] = (v), \ 137 ((u_int8_t *)(p))[1] = (v) >> 8, \ 138 ((u_int8_t *)(p))[2] = (v) >> 16,\ 139 ((u_int8_t *)(p))[3] = (v) >> 24) 140 #endif 141 142 /* 143 * BIOS Parameter Block (BPB) for DOS 3.3 144 */ 145 struct byte_bpb33 { 146 int8_t bpbBytesPerSec[2]; /* bytes per sector */ 147 int8_t bpbSecPerClust; /* sectors per cluster */ 148 int8_t bpbResSectors[2]; /* number of reserved sectors */ 149 int8_t bpbFATs; /* number of FATs */ 150 int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 151 int8_t bpbSectors[2]; /* total number of sectors */ 152 int8_t bpbMedia; /* media descriptor */ 153 int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 154 int8_t bpbSecPerTrack[2]; /* sectors per track */ 155 int8_t bpbHeads[2]; /* number of heads */ 156 int8_t bpbHiddenSecs[2]; /* number of hidden sectors */ 157 }; 158 159 /* 160 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3, 161 * and bpbHugeSectors is not in the 3.3 bpb. 162 */ 163 struct byte_bpb50 { 164 int8_t bpbBytesPerSec[2]; /* bytes per sector */ 165 int8_t bpbSecPerClust; /* sectors per cluster */ 166 int8_t bpbResSectors[2]; /* number of reserved sectors */ 167 int8_t bpbFATs; /* number of FATs */ 168 int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 169 int8_t bpbSectors[2]; /* total number of sectors */ 170 int8_t bpbMedia; /* media descriptor */ 171 int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 172 int8_t bpbSecPerTrack[2]; /* sectors per track */ 173 int8_t bpbHeads[2]; /* number of heads */ 174 int8_t bpbHiddenSecs[4]; /* number of hidden sectors */ 175 int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */ 176 }; 177 178 /* 179 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50. 180 */ 181 struct byte_bpb710 { 182 u_int8_t bpbBytesPerSec[2]; /* bytes per sector */ 183 u_int8_t bpbSecPerClust; /* sectors per cluster */ 184 u_int8_t bpbResSectors[2]; /* number of reserved sectors */ 185 u_int8_t bpbFATs; /* number of FATs */ 186 u_int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 187 u_int8_t bpbSectors[2]; /* total number of sectors */ 188 u_int8_t bpbMedia; /* media descriptor */ 189 u_int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 190 u_int8_t bpbSecPerTrack[2]; /* sectors per track */ 191 u_int8_t bpbHeads[2]; /* number of heads */ 192 u_int8_t bpbHiddenSecs[4]; /* # of hidden sectors */ 193 u_int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */ 194 u_int8_t bpbBigFATsecs[4]; /* like bpbFATsecs for FAT32 */ 195 u_int8_t bpbExtFlags[2]; /* extended flags: */ 196 u_int8_t bpbFSVers[2]; /* filesystem version */ 197 u_int8_t bpbRootClust[4]; /* start cluster for root directory */ 198 u_int8_t bpbFSInfo[2]; /* filesystem info structure sector */ 199 u_int8_t bpbBackup[2]; /* backup boot sector */ 200 /* There is a 12 byte filler here, but we ignore it */ 201 }; 202 203 /* 204 * FAT32 FSInfo block. 205 */ 206 struct fsinfo { 207 u_int8_t fsisig1[4]; 208 u_int8_t fsifill1[480]; 209 u_int8_t fsisig2[4]; 210 u_int8_t fsinfree[4]; 211 u_int8_t fsinxtfree[4]; 212 u_int8_t fsifill2[12]; 213 u_int8_t fsisig3[4]; 214 u_int8_t fsifill3[508]; 215 u_int8_t fsisig4[4]; 216 }; 217