sys/vfs/msdosfs/bpb.h

   1 /* $FreeBSD: head/sys/fs/msdosfs/bpb.h 203827 2010-02-13 12:41:07Z kib $ */
   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 _VFS_MSDOSFS_BPB_H_
  21 #define _VFS_MSDOSFS_BPB_H_
  22
  23 /*
  24  * BIOS Parameter Block (BPB) for DOS 3.3
  25  */
  26 struct bpb33 {
  27         u_int16_t       bpbBytesPerSec; /* bytes per sector */
  28         u_int8_t        bpbSecPerClust; /* sectors per cluster */
  29         u_int16_t       bpbResSectors;  /* number of reserved sectors */
  30         u_int8_t        bpbFATs;        /* number of FATs */
  31         u_int16_t       bpbRootDirEnts; /* number of root directory entries */
  32         u_int16_t       bpbSectors;     /* total number of sectors */
  33         u_int8_t        bpbMedia;       /* media descriptor */
  34         u_int16_t       bpbFATsecs;     /* number of sectors per FAT */
  35         u_int16_t       bpbSecPerTrack; /* sectors per track */
  36         u_int16_t       bpbHeads;       /* number of heads */
  37         u_int16_t       bpbHiddenSecs;  /* number of hidden sectors */
  38 };
  39
  40 /*
  41  * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
  42  * and bpbHugeSectors is not in the 3.3 bpb.
  43  */
  44 struct bpb50 {
  45         u_int16_t       bpbBytesPerSec; /* bytes per sector */
  46         u_int8_t        bpbSecPerClust; /* sectors per cluster */
  47         u_int16_t       bpbResSectors;  /* number of reserved sectors */
  48         u_int8_t        bpbFATs;        /* number of FATs */
  49         u_int16_t       bpbRootDirEnts; /* number of root directory entries */
  50         u_int16_t       bpbSectors;     /* total number of sectors */
  51         u_int8_t        bpbMedia;       /* media descriptor */
  52         u_int16_t       bpbFATsecs;     /* number of sectors per FAT */
  53         u_int16_t       bpbSecPerTrack; /* sectors per track */
  54         u_int16_t       bpbHeads;       /* number of heads */
  55         u_int32_t       bpbHiddenSecs;  /* # of hidden sectors */
  56         u_int32_t       bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
  57 };
  58
  59 /*
  60  * BPB for DOS 7.10 (FAT32).  This one has a few extensions to bpb50.
  61  */
  62 struct bpb710 {
  63         u_int16_t       bpbBytesPerSec; /* bytes per sector */
  64         u_int8_t        bpbSecPerClust; /* sectors per cluster */
  65         u_int16_t       bpbResSectors;  /* number of reserved sectors */
  66         u_int8_t        bpbFATs;        /* number of FATs */
  67         u_int16_t       bpbRootDirEnts; /* number of root directory entries */
  68         u_int16_t       bpbSectors;     /* total number of sectors */
  69         u_int8_t        bpbMedia;       /* media descriptor */
  70         u_int16_t       bpbFATsecs;     /* number of sectors per FAT */
  71         u_int16_t       bpbSecPerTrack; /* sectors per track */
  72         u_int16_t       bpbHeads;       /* number of heads */
  73         u_int32_t       bpbHiddenSecs;  /* # of hidden sectors */
  74         u_int32_t       bpbHugeSectors; /* # of sectors if bpbSectors == 0 */
  75         u_int32_t       bpbBigFATsecs;  /* like bpbFATsecs for FAT32 */
  76         u_int16_t       bpbExtFlags;    /* extended flags: */
  77 #define FATNUM          0xf             /* mask for numbering active FAT */
  78 #define FATMIRROR       0x80            /* FAT is mirrored (like it always was) */
  79         u_int16_t       bpbFSVers;      /* filesystem version */
  80 #define FSVERS          0               /* currently only 0 is understood */
  81         u_int32_t       bpbRootClust;   /* start cluster for root directory */
  82         u_int16_t       bpbFSInfo;      /* filesystem info structure sector */
  83         u_int16_t       bpbBackup;      /* backup boot sector */
  84         u_int8_t        bpbReserved[12]; /* reserved for future expansion */
  85 };
  86
  87 #ifdef  atari
  88 /*
  89  * BPB for gemdos filesystems. Atari leaves the obsolete stuff undefined.
  90  * Currently there is no need for a separate BPB structure.
  91  */
  92 #if 0
  93 struct bpb_a {
  94         u_int16_t       bpbBytesPerSec; /* bytes per sector             */
  95         u_int8_t        bpbSecPerClust; /* sectors per cluster          */
  96         u_int16_t       bpbResSectors;  /* number of reserved sectors   */
  97         u_int8_t        bpbFATs;        /* number of FATs               */
  98         u_int16_t       bpbRootDirEnts; /* number of root directory entries */
  99         u_int16_t       bpbSectors;     /* total number of sectors      */
 100         u_int8_t        bpbUseless1;    /* meaningless on gemdos fs     */
 101         u_int16_t       bpbFATsecs;     /* number of sectors per FAT    */
 102         u_int16_t       bpbUseless2;    /* meaningless for harddisk fs  */
 103         u_int16_t       bpbUseless3;    /* meaningless for harddisk fs  */
 104         u_int16_t       bpbHiddenSecs;  /* the TOS-BIOS ignores this    */
 105 };
 106 #endif
 107 #endif  /* atari */
 108
 109 /*
 110  * The following structures represent how the bpb's look on disk.  shorts
 111  * and longs are just character arrays of the appropriate length.  This is
 112  * because the compiler forces shorts and longs to align on word or
 113  * halfword boundaries.
 114  */
 115
 116 #include <sys/endian.h>
 117
 118 #define getushort(x)    le16dec(x)
 119 #define getulong(x)     le32dec(x)
 120 #define putushort(p, v) le16enc(p, v)
 121 #define putulong(p, v)  le32enc(p, v)
 122
 123 /*
 124  * BIOS Parameter Block (BPB) for DOS 3.3
 125  */
 126 struct byte_bpb33 {
 127         int8_t bpbBytesPerSec[2];       /* bytes per sector */
 128         int8_t bpbSecPerClust;          /* sectors per cluster */
 129         int8_t bpbResSectors[2];        /* number of reserved sectors */
 130         int8_t bpbFATs;                 /* number of FATs */
 131         int8_t bpbRootDirEnts[2];       /* number of root directory entries */
 132         int8_t bpbSectors[2];           /* total number of sectors */
 133         int8_t bpbMedia;                /* media descriptor */
 134         int8_t bpbFATsecs[2];           /* number of sectors per FAT */
 135         int8_t bpbSecPerTrack[2];       /* sectors per track */
 136         int8_t bpbHeads[2];             /* number of heads */
 137         int8_t bpbHiddenSecs[2];        /* number of hidden sectors */
 138 };
 139
 140 /*
 141  * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
 142  * and bpbHugeSectors is not in the 3.3 bpb.
 143  */
 144 struct byte_bpb50 {
 145         int8_t bpbBytesPerSec[2];       /* bytes per sector */
 146         int8_t bpbSecPerClust;          /* sectors per cluster */
 147         int8_t bpbResSectors[2];        /* number of reserved sectors */
 148         int8_t bpbFATs;                 /* number of FATs */
 149         int8_t bpbRootDirEnts[2];       /* number of root directory entries */
 150         int8_t bpbSectors[2];           /* total number of sectors */
 151         int8_t bpbMedia;                /* media descriptor */
 152         int8_t bpbFATsecs[2];           /* number of sectors per FAT */
 153         int8_t bpbSecPerTrack[2];       /* sectors per track */
 154         int8_t bpbHeads[2];             /* number of heads */
 155         int8_t bpbHiddenSecs[4];        /* number of hidden sectors */
 156         int8_t bpbHugeSectors[4];       /* # of sectors if bpbSectors == 0 */
 157 };
 158
 159 /*
 160  * BPB for DOS 7.10 (FAT32).  This one has a few extensions to bpb50.
 161  */
 162 struct byte_bpb710 {
 163         u_int8_t bpbBytesPerSec[2];     /* bytes per sector */
 164         u_int8_t bpbSecPerClust;        /* sectors per cluster */
 165         u_int8_t bpbResSectors[2];      /* number of reserved sectors */
 166         u_int8_t bpbFATs;               /* number of FATs */
 167         u_int8_t bpbRootDirEnts[2];     /* number of root directory entries */
 168         u_int8_t bpbSectors[2];         /* total number of sectors */
 169         u_int8_t bpbMedia;              /* media descriptor */
 170         u_int8_t bpbFATsecs[2];         /* number of sectors per FAT */
 171         u_int8_t bpbSecPerTrack[2];     /* sectors per track */
 172         u_int8_t bpbHeads[2];           /* number of heads */
 173         u_int8_t bpbHiddenSecs[4];      /* # of hidden sectors */
 174         u_int8_t bpbHugeSectors[4];     /* # of sectors if bpbSectors == 0 */
 175         u_int8_t bpbBigFATsecs[4];      /* like bpbFATsecs for FAT32 */
 176         u_int8_t bpbExtFlags[2];        /* extended flags: */
 177         u_int8_t bpbFSVers[2];          /* filesystem version */
 178         u_int8_t bpbRootClust[4];       /* start cluster for root directory */
 179         u_int8_t bpbFSInfo[2];          /* filesystem info structure sector */
 180         u_int8_t bpbBackup[2];          /* backup boot sector */
 181         u_int8_t bpbReserved[12];       /* reserved for future expansion */
 182 };
 183
 184 /*
 185  * FAT32 FSInfo block.
 186  */
 187 struct fsinfo {
 188         u_int8_t fsisig1[4];
 189         u_int8_t fsifill1[480];
 190         u_int8_t fsisig2[4];
 191         u_int8_t fsinfree[4];
 192         u_int8_t fsinxtfree[4];
 193         u_int8_t fsifill2[12];
 194         u_int8_t fsisig3[4];
 195         u_int8_t fsifill3[508];
 196         u_int8_t fsisig4[4];
 197 };
 198
 199 #endif /* !_VFS_MSDOSFS_BPB_H_ */