sys/vfs/msdosfs/bpb.h

   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 };