sys/fs/msdosfs/bpb.h

   1 /*      $NetBSD: bpb.h,v 1.5 2006/11/30 15:59:23 christos Exp $ */
   2
   3 /*
   4  * Written by Paul Popelka (paulp@uts.amdahl.com)
   5  *
   6  * You can do anything you want with this software, just don't say you wrote
   7  * it, and don't remove this notice.
   8  *
   9  * This software is provided "as is".
  10  *
  11  * The author supplies this software to be publicly redistributed on the
  12  * understanding that the author is not responsible for the correct
  13  * functioning of this software in any circumstances and is not liable for
  14  * any damages caused by this software.
  15  *
  16  * October 1992
  17  */
  18
  19 #ifndef _MSDOSFS_BPB_H_
  20 #define _MSDOSFS_BPB_H_
  21
  22 /*
  23  * BIOS Parameter Block (BPB) for DOS 3.3
  24  */
  25 struct bpb33 {
  26         u_int16_t       bpbBytesPerSec; /* bytes per sector */
  27         u_int8_t        bpbSecPerClust; /* sectors per cluster */
  28         u_int16_t       bpbResSectors;  /* number of reserved sectors */
  29         u_int8_t        bpbFATs;        /* number of FATs */
  30         u_int16_t       bpbRootDirEnts; /* number of root directory entries */
  31         u_int16_t       bpbSectors;     /* total number of sectors */
  32         u_int8_t        bpbMedia;       /* media descriptor */
  33         u_int16_t       bpbFATsecs;     /* number of sectors per FAT */
  34         u_int16_t       bpbSecPerTrack; /* sectors per track */
  35         u_int16_t       bpbHeads;       /* number of heads */
  36         u_int16_t       bpbHiddenSecs;  /* number of hidden sectors */
  37 };
  38
  39 /*
  40  * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
  41  * and bpbHugeSectors is not in the 3.3 bpb.
  42  */
  43 struct bpb50 {
  44         u_int16_t       bpbBytesPerSec; /* bytes per sector */
  45         u_int8_t        bpbSecPerClust; /* sectors per cluster */
  46         u_int16_t       bpbResSectors;  /* number of reserved sectors */
  47         u_int8_t        bpbFATs;        /* number of FATs */
  48         u_int16_t       bpbRootDirEnts; /* number of root directory entries */
  49         u_int16_t       bpbSectors;     /* total number of sectors */
  50         u_int8_t        bpbMedia;       /* media descriptor */
  51         u_int16_t       bpbFATsecs;     /* number of sectors per FAT */
  52         u_int16_t       bpbSecPerTrack; /* sectors per track */
  53         u_int16_t       bpbHeads;       /* number of heads */
  54         u_int32_t       bpbHiddenSecs;  /* # of hidden sectors */
  55         u_int32_t       bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
  56 };
  57
  58 /*
  59  * BPB for DOS 7.10 (FAT32).  This one has a few extensions to bpb50.
  60  */
  61 struct bpb710 {
  62         u_int16_t       bpbBytesPerSec; /* bytes per sector */
  63         u_int8_t        bpbSecPerClust; /* sectors per cluster */
  64         u_int16_t       bpbResSectors;  /* number of reserved sectors */
  65         u_int8_t        bpbFATs;        /* number of FATs */
  66         u_int16_t       bpbRootDirEnts; /* number of root directory entries */
  67         u_int16_t       bpbSectors;     /* total number of sectors */
  68         u_int8_t        bpbMedia;       /* media descriptor */
  69         u_int16_t       bpbFATsecs;     /* number of sectors per FAT */
  70         u_int16_t       bpbSecPerTrack; /* sectors per track */
  71         u_int16_t       bpbHeads;       /* number of heads */
  72         u_int32_t       bpbHiddenSecs;  /* # of hidden sectors */
  73         u_int32_t       bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
  74         u_int32_t       bpbBigFATsecs;  /* like bpbFATsecs for FAT32 */
  75         u_int16_t       bpbExtFlags;    /* extended flags: */
  76 #define FATNUM          0xf             /* mask for numbering active FAT */
  77 #define FATMIRROR       0x80            /* FAT is mirrored (like it always was) */
  78         u_int16_t       bpbFSVers;      /* filesystem version */
  79 #define FSVERS          0               /* currently only 0 is understood */
  80         u_int32_t       bpbRootClust;   /* start cluster for root directory */
  81         u_int16_t       bpbFSInfo;      /* filesystem info structure sector */
  82         u_int16_t       bpbBackup;      /* backup boot sector */
  83         u_int8_t        bpbReserved[12]; /* Reserved for future expansion */
  84 };
  85
  86 #ifdef  atari
  87 /*
  88  * BPB for gemdos filesystems. Atari leaves the obsolete stuff undefined.
  89  * Currently there is no need for a separate BPB structure.
  90  */
  91 #if 0
  92 struct bpb_a {
  93         u_int16_t       bpbBytesPerSec; /* bytes per sector             */
  94         u_int8_t        bpbSecPerClust; /* sectors per cluster          */
  95         u_int16_t       bpbResSectors;  /* number of reserved sectors   */
  96         u_int8_t        bpbFATs;        /* number of FATs               */
  97         u_int16_t       bpbRootDirEnts; /* number of root directory entries */
  98         u_int16_t       bpbSectors;     /* total number of sectors      */
  99         u_int8_t        bpbUseless1;    /* meaningless on gemdos fs     */
 100         u_int16_t       bpbFATsecs;     /* number of sectors per FAT    */
 101         u_int16_t       bpbUseless2;    /* meaningless for harddisk fs  */
 102         u_int16_t       bpbUseless3;    /* meaningless for harddisk fs  */
 103         u_int16_t       bpbHiddenSecs;  /* the TOS-BIOS ignores this    */
 104 };
 105 #endif
 106 #endif  /* atari */
 107
 108 /*
 109  * The following structures represent how the bpb's look on disk.  shorts
 110  * and longs are just character arrays of the appropriate length.  This is
 111  * because the compiler forces shorts and longs to align on word or
 112  * halfword boundaries.
 113  */
 114
 115 #include <sys/endian.h>
 116
 117 #define getushort(p)    le16dec(p)
 118 #define getulong(p)     le32dec(p)
 119 #define putushort(p, v) le16enc((p), (v))
 120 #define putulong(p, v)  le32enc((p), (v))
 121
 122 /*
 123  * BIOS Parameter Block (BPB) for DOS 3.3
 124  */
 125 struct byte_bpb33 {
 126         int8_t bpbBytesPerSec[2];       /* bytes per sector */
 127         int8_t bpbSecPerClust;          /* sectors per cluster */
 128         int8_t bpbResSectors[2];        /* number of reserved sectors */
 129         int8_t bpbFATs;                 /* number of FATs */
 130         int8_t bpbRootDirEnts[2];       /* number of root directory entries */
 131         int8_t bpbSectors[2];           /* total number of sectors */
 132         int8_t bpbMedia;                /* media descriptor */
 133         int8_t bpbFATsecs[2];           /* number of sectors per FAT */
 134         int8_t bpbSecPerTrack[2];       /* sectors per track */
 135         int8_t bpbHeads[2];             /* number of heads */
 136         int8_t bpbHiddenSecs[2];        /* number of hidden sectors */
 137 };
 138
 139 /*
 140  * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
 141  * and bpbHugeSectors is not in the 3.3 bpb.
 142  */
 143 struct byte_bpb50 {
 144         int8_t bpbBytesPerSec[2];       /* bytes per sector */
 145         int8_t bpbSecPerClust;          /* sectors per cluster */
 146         int8_t bpbResSectors[2];        /* number of reserved sectors */
 147         int8_t bpbFATs;                 /* number of FATs */
 148         int8_t bpbRootDirEnts[2];       /* number of root directory entries */
 149         int8_t bpbSectors[2];           /* total number of sectors */
 150         int8_t bpbMedia;                /* media descriptor */
 151         int8_t bpbFATsecs[2];           /* number of sectors per FAT */
 152         int8_t bpbSecPerTrack[2];       /* sectors per track */
 153         int8_t bpbHeads[2];             /* number of heads */
 154         int8_t bpbHiddenSecs[4];        /* number of hidden sectors */
 155         int8_t bpbHugeSectors[4];       /* # of sectors if bpbSectors == 0 */
 156 };
 157
 158 /*
 159  * BPB for DOS 7.10 (FAT32).  This one has a few extensions to bpb50.
 160  */
 161 struct byte_bpb710 {
 162         u_int8_t bpbBytesPerSec[2];     /* bytes per sector */
 163         u_int8_t bpbSecPerClust;        /* sectors per cluster */
 164         u_int8_t bpbResSectors[2];      /* number of reserved sectors */
 165         u_int8_t bpbFATs;               /* number of FATs */
 166         u_int8_t bpbRootDirEnts[2];     /* number of root directory entries */
 167         u_int8_t bpbSectors[2];         /* total number of sectors */
 168         u_int8_t bpbMedia;              /* media descriptor */
 169         u_int8_t bpbFATsecs[2];         /* number of sectors per FAT */
 170         u_int8_t bpbSecPerTrack[2];     /* sectors per track */
 171         u_int8_t bpbHeads[2];           /* number of heads */
 172         u_int8_t bpbHiddenSecs[4];      /* # of hidden sectors */
 173         u_int8_t bpbHugeSectors[4];     /* # of sectors if bpbSectors == 0 */
 174         u_int8_t bpbBigFATsecs[4];      /* like bpbFATsecs for FAT32 */
 175         u_int8_t bpbExtFlags[2];        /* extended flags: */
 176         u_int8_t bpbFSVers[2];          /* filesystem version */
 177         u_int8_t bpbRootClust[4];       /* start cluster for root directory */
 178         u_int8_t bpbFSInfo[2];          /* filesystem info structure sector */
 179         u_int8_t bpbBackup[2];          /* backup boot sector */
 180         u_int8_t bpbReserved[12];       /* Reserved for future expansion */
 181 };
 182
 183 /*
 184  * FAT32 FSInfo block.
 185  */
 186 struct fsinfo {
 187         u_int8_t fsisig1[4];
 188         u_int8_t fsifill1[480];
 189         u_int8_t fsisig2[4];
 190         u_int8_t fsinfree[4];
 191         u_int8_t fsinxtfree[4];
 192         u_int8_t fsifill2[12];
 193         u_int8_t fsisig3[4];
 194         u_int8_t fsifill3[508];
 195         u_int8_t fsisig4[4];
 196 };
 197 #endif /* _MSDOSFS_BPB_H_ */