fat_rec.h

微软win2k的fsrec源码,驱动中展示了如何启动文件系统驱动程序,如何根据硬盘和光盘上的文件系统类型调用不同的文件系统驱动程序

/*++

Copyright (c) 1992  Microsoft Corporation

Module Name:

    fat_rec.h

Abstract:

    This module contains the mini-file system recognizer for FAT.

Author:

    Darryl E. Havens (darrylh) 8-dec-1992

Environment:

    Kernel mode, local to I/O system

Revision History:


--*/

//
//  The following types and macros are used to help unpack the packed and
//  misaligned fields found in the Bios parameter block
//

typedef union _UCHAR1 {
    UCHAR  Uchar[1];
    UCHAR  ForceAlignment;
} UCHAR1, *PUCHAR1;

typedef union _UCHAR2 {
    UCHAR  Uchar[2];
    USHORT ForceAlignment;
} UCHAR2, *PUCHAR2;

typedef union _UCHAR4 {
    UCHAR  Uchar[4];
    ULONG  ForceAlignment;
} UCHAR4, *PUCHAR4;

//
//  This macro copies an unaligned src byte to an aligned dst byte
//

#define CopyUchar1(Dst,Src) {                                \
    *((UCHAR1 *)(Dst)) = *((UNALIGNED UCHAR1 *)(Src)); \
    }

//
//  This macro copies an unaligned src word to an aligned dst word
//

#define CopyUchar2(Dst,Src) {                                \
    *((UCHAR2 *)(Dst)) = *((UNALIGNED UCHAR2 *)(Src)); \
    }

//
//  This macro copies an unaligned src longword to an aligned dsr longword
//

#define CopyUchar4(Dst,Src) {                                \
    *((UCHAR4 *)(Dst)) = *((UNALIGNED UCHAR4 *)(Src)); \
    }

//
//  Define the Packed and Unpacked BIOS Parameter Block
//

typedef struct _PACKED_BIOS_PARAMETER_BLOCK {
    UCHAR  BytesPerSector[2];                       // offset = 0x000  0
    UCHAR  SectorsPerCluster[1];                    // offset = 0x002  2
    UCHAR  ReservedSectors[2];                      // offset = 0x003  3
    UCHAR  Fats[1];                                 // offset = 0x005  5
    UCHAR  RootEntries[2];                          // offset = 0x006  6
    UCHAR  Sectors[2];                              // offset = 0x008  8
    UCHAR  Media[1];                                // offset = 0x00A 10
    UCHAR  SectorsPerFat[2];                        // offset = 0x00B 11
    UCHAR  SectorsPerTrack[2];                      // offset = 0x00D 13
    UCHAR  Heads[2];                                // offset = 0x00F 15
    UCHAR  HiddenSectors[4];                        // offset = 0x011 17
    UCHAR  LargeSectors[4];                         // offset = 0x015 21
} PACKED_BIOS_PARAMETER_BLOCK;                      // sizeof = 0x019 25

typedef PACKED_BIOS_PARAMETER_BLOCK *PPACKED_BIOS_PARAMETER_BLOCK;

typedef struct BIOS_PARAMETER_BLOCK {
    USHORT BytesPerSector;
    UCHAR  SectorsPerCluster;
    USHORT ReservedSectors;
    UCHAR  Fats;
    USHORT RootEntries;
    USHORT Sectors;
    UCHAR  Media;
    USHORT SectorsPerFat;
    USHORT SectorsPerTrack;
    USHORT Heads;
    ULONG  HiddenSectors;
    ULONG  LargeSectors;
} BIOS_PARAMETER_BLOCK, *PBIOS_PARAMETER_BLOCK;

//
//  Define the boot sector
//

typedef struct _PACKED_BOOT_SECTOR {
    UCHAR Jump[3];                                  // offset = 0x000   0
    UCHAR Oem[8];                                   // offset = 0x003   3
    PACKED_BIOS_PARAMETER_BLOCK PackedBpb;          // offset = 0x00B  11
    UCHAR PhysicalDriveNumber;                      // offset = 0x024  36
    UCHAR Reserved;                                 // offset = 0x025  37
    UCHAR Signature;                                // offset = 0x026  38
    UCHAR Id[4];                                    // offset = 0x027  39
    UCHAR VolumeLabel[11];                          // offset = 0x02B  43
    UCHAR SystemId[8];                              // offset = 0x036  54
} PACKED_BOOT_SECTOR;                               // sizeof = 0x03E  62

typedef PACKED_BOOT_SECTOR *PPACKED_BOOT_SECTOR;

//
// Define the functions provided by this driver.
//

BOOLEAN
IsFatVolume(
    IN PPACKED_BOOT_SECTOR Buffer
    );

VOID
UnpackBiosParameterBlock(
    IN PPACKED_BIOS_PARAMETER_BLOCK Bios,
    OUT PBIOS_PARAMETER_BLOCK UnpackedBios
    );