sys/vfs/msdosfs/bpb.h

   1 /* $FreeBSD$ */
   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 #ifndef _FS_MSDOSFS_BPB_H_
  21 #define _FS_MSDOSFS_BPB_H_
  22
  23 #include <sys/types.h>
  24
  25 /*
  26  * BIOS Parameter Block (BPB) for DOS 3.3
  27  */
  28 struct bpb33 {
  29         uint16_t        bpbBytesPerSec; /* bytes per sector */
  30         uint8_t         bpbSecPerClust; /* sectors per cluster */
  31         uint16_t        bpbResSectors;  /* number of reserved sectors */
  32         uint8_t         bpbFATs;        /* number of FATs */
  33         uint16_t        bpbRootDirEnts; /* number of root directory entries */
  34         uint16_t        bpbSectors;     /* total number of sectors */
  35         uint8_t         bpbMedia;       /* media descriptor */
  36         uint16_t        bpbFATsecs;     /* number of sectors per FAT */
  37         uint16_t        bpbSecPerTrack; /* sectors per track */
  38         uint16_t        bpbHeads;       /* number of heads */
  39         uint16_t        bpbHiddenSecs;  /* number of hidden sectors */
  40 };
  41
  42 /*
  43  * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
  44  * and bpbHugeSectors is not in the 3.3 bpb.
  45  */
  46 struct bpb50 {
  47         uint16_t        bpbBytesPerSec; /* bytes per sector */
  48         uint8_t         bpbSecPerClust; /* sectors per cluster */
  49         uint16_t        bpbResSectors;  /* number of reserved sectors */
  50         uint8_t         bpbFATs;        /* number of FATs */
  51         uint16_t        bpbRootDirEnts; /* number of root directory entries */
  52         uint16_t        bpbSectors;     /* total number of sectors */
  53         uint8_t         bpbMedia;       /* media descriptor */
  54         uint16_t        bpbFATsecs;     /* number of sectors per FAT */
  55         uint16_t        bpbSecPerTrack; /* sectors per track */
  56         uint16_t        bpbHeads;       /* number of heads */
  57         uint32_t        bpbHiddenSecs;  /* # of hidden sectors */
  58         uint32_t        bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
  59 };
  60
  61 /*
  62  * BPB for DOS 7.10 (FAT32).  This one has a few extensions to bpb50.
  63  */
  64 struct bpb710 {
  65         uint16_t        bpbBytesPerSec; /* bytes per sector */
  66         uint8_t         bpbSecPerClust; /* sectors per cluster */
  67         uint16_t        bpbResSectors;  /* number of reserved sectors */
  68         uint8_t         bpbFATs;        /* number of FATs */
  69         uint16_t        bpbRootDirEnts; /* number of root directory entries */
  70         uint16_t        bpbSectors;     /* total number of sectors */
  71         uint8_t         bpbMedia;       /* media descriptor */
  72         uint16_t        bpbFATsecs;     /* number of sectors per FAT */
  73         uint16_t        bpbSecPerTrack; /* sectors per track */
  74         uint16_t        bpbHeads;       /* number of heads */
  75         uint32_t        bpbHiddenSecs;  /* # of hidden sectors */
  76         uint32_t        bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
  77         uint32_t        bpbBigFATsecs;  /* like bpbFATsecs for FAT32 */
  78         uint16_t        bpbExtFlags;    /* extended flags: */
  79 #define FATNUM          0xf             /* mask for numbering active FAT */
  80 #define FATMIRROR       0x80            /* FAT is mirrored (like it always was) */
  81         uint16_t        bpbFSVers;      /* filesystem version */
  82 #define FSVERS          0               /* currently only 0 is understood */
  83         uint32_t        bpbRootClust;   /* start cluster for root directory */
  84         uint16_t        bpbFSInfo;      /* filesystem info structure sector */
  85         uint16_t        bpbBackup;      /* backup boot sector */
  86         uint8_t         bpbReserved[12]; /* reserved for future expansion */
  87 };
  88
  89 /*
  90  * The following structures represent how the bpb's look on disk.  shorts
  91  * and longs are just character arrays of the appropriate length.  This is
  92  * because the compiler forces shorts and longs to align on word or
  93  * halfword boundaries.
  94  */
  95
  96 #include <sys/endian.h>
  97
  98 #define getushort(x)    le16dec(x)
  99 #define getulong(x)     le32dec(x)
 100 #define putushort(p, v) le16enc(p, v)
 101 #define putulong(p, v)  le32enc(p, v)
 102
 103 /*
 104  * BIOS Parameter Block (BPB) for DOS 3.3
 105  */
 106 struct byte_bpb33 {
 107         int8_t bpbBytesPerSec[2];       /* bytes per sector */
 108         int8_t bpbSecPerClust;          /* sectors per cluster */
 109         int8_t bpbResSectors[2];        /* number of reserved sectors */
 110         int8_t bpbFATs;                 /* number of FATs */
 111         int8_t bpbRootDirEnts[2];       /* number of root directory entries */
 112         int8_t bpbSectors[2];           /* total number of sectors */
 113         int8_t bpbMedia;                /* media descriptor */
 114         int8_t bpbFATsecs[2];           /* number of sectors per FAT */
 115         int8_t bpbSecPerTrack[2];       /* sectors per track */
 116         int8_t bpbHeads[2];             /* number of heads */
 117         int8_t bpbHiddenSecs[2];        /* number of hidden sectors */
 118 };
 119
 120 /*
 121  * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
 122  * and bpbHugeSectors is not in the 3.3 bpb.
 123  */
 124 struct byte_bpb50 {
 125         int8_t bpbBytesPerSec[2];       /* bytes per sector */
 126         int8_t bpbSecPerClust;          /* sectors per cluster */
 127         int8_t bpbResSectors[2];        /* number of reserved sectors */
 128         int8_t bpbFATs;                 /* number of FATs */
 129         int8_t bpbRootDirEnts[2];       /* number of root directory entries */
 130         int8_t bpbSectors[2];           /* total number of sectors */
 131         int8_t bpbMedia;                /* media descriptor */
 132         int8_t bpbFATsecs[2];           /* number of sectors per FAT */
 133         int8_t bpbSecPerTrack[2];       /* sectors per track */
 134         int8_t bpbHeads[2];             /* number of heads */
 135         int8_t bpbHiddenSecs[4];        /* number of hidden sectors */
 136         int8_t bpbHugeSectors[4];       /* # of sectors if bpbSectors == 0 */
 137 };
 138
 139 /*
 140  * BPB for DOS 7.10 (FAT32).  This one has a few extensions to bpb50.
 141  */
 142 struct byte_bpb710 {
 143         uint8_t bpbBytesPerSec[2];      /* bytes per sector */
 144         uint8_t bpbSecPerClust;         /* sectors per cluster */
 145         uint8_t bpbResSectors[2];       /* number of reserved sectors */
 146         uint8_t bpbFATs;                /* number of FATs */
 147         uint8_t bpbRootDirEnts[2];      /* number of root directory entries */
 148         uint8_t bpbSectors[2];          /* total number of sectors */
 149         uint8_t bpbMedia;               /* media descriptor */
 150         uint8_t bpbFATsecs[2];          /* number of sectors per FAT */
 151         uint8_t bpbSecPerTrack[2];      /* sectors per track */
 152         uint8_t bpbHeads[2];            /* number of heads */
 153         uint8_t bpbHiddenSecs[4];       /* # of hidden sectors */
 154         uint8_t bpbHugeSectors[4];      /* # of sectors if bpbSectors == 0 */
 155         uint8_t bpbBigFATsecs[4];       /* like bpbFATsecs for FAT32 */
 156         uint8_t bpbExtFlags[2];         /* extended flags: */
 157         uint8_t bpbFSVers[2];           /* filesystem version */
 158         uint8_t bpbRootClust[4];        /* start cluster for root directory */
 159         uint8_t bpbFSInfo[2];           /* filesystem info structure sector */
 160         uint8_t bpbBackup[2];           /* backup boot sector */
 161         uint8_t bpbReserved[12];        /* reserved for future expansion */
 162 };
 163
 164 /*
 165  * FAT32 FSInfo block.
 166  */
 167 struct fsinfo {
 168         uint8_t fsisig1[4];
 169         uint8_t fsifill1[480];
 170         uint8_t fsisig2[4];
 171         uint8_t fsinfree[4];
 172         uint8_t fsinxtfree[4];
 173         uint8_t fsifill2[12];
 174         uint8_t fsisig3[4];
 175 };
 176 #endif /* !_FS_MSDOSFS_BPB_H_ */