138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/*++
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Copyright (c) 1992 Microsoft Corporation
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Module Name:
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fat_rec.h
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Abstract:
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This module contains the mini-file system recognizer for FAT.
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Author:
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Darryl E. Havens (darrylh) 8-dec-1992
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Environment:
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Kernel mode, local to I/O system
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Revision History:
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*/
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// The following types and macros are used to help unpack the packed and
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// misaligned fields found in the Bios parameter block
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typedef union _UCHAR1 {
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UCHAR Uchar[1];
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UCHAR ForceAlignment;
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} UCHAR1, *PUCHAR1;
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typedef union _UCHAR2 {
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UCHAR Uchar[2];
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USHORT ForceAlignment;
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} UCHAR2, *PUCHAR2;
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typedef union _UCHAR4 {
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UCHAR Uchar[4];
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ULONG ForceAlignment;
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} UCHAR4, *PUCHAR4;
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// This macro copies an unaligned src byte to an aligned dst byte
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#define CopyUchar1(Dst,Src) { \
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*((UCHAR1 *)(Dst)) = *((UNALIGNED UCHAR1 *)(Src)); \
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}
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// This macro copies an unaligned src word to an aligned dst word
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#define CopyUchar2(Dst,Src) { \
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*((UCHAR2 *)(Dst)) = *((UNALIGNED UCHAR2 *)(Src)); \
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}
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// This macro copies an unaligned src longword to an aligned dsr longword
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#define CopyUchar4(Dst,Src) { \
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*((UCHAR4 *)(Dst)) = *((UNALIGNED UCHAR4 *)(Src)); \
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}
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// Define the Packed and Unpacked BIOS Parameter Block
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typedef struct _PACKED_BIOS_PARAMETER_BLOCK {
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UCHAR BytesPerSector[2]; // offset = 0x000 0
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UCHAR SectorsPerCluster[1]; // offset = 0x002 2
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UCHAR ReservedSectors[2]; // offset = 0x003 3
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UCHAR Fats[1]; // offset = 0x005 5
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UCHAR RootEntries[2]; // offset = 0x006 6
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UCHAR Sectors[2]; // offset = 0x008 8
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UCHAR Media[1]; // offset = 0x00A 10
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UCHAR SectorsPerFat[2]; // offset = 0x00B 11
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UCHAR SectorsPerTrack[2]; // offset = 0x00D 13
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UCHAR Heads[2]; // offset = 0x00F 15
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UCHAR HiddenSectors[4]; // offset = 0x011 17
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UCHAR LargeSectors[4]; // offset = 0x015 21
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} PACKED_BIOS_PARAMETER_BLOCK; // sizeof = 0x019 25
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typedef PACKED_BIOS_PARAMETER_BLOCK *PPACKED_BIOS_PARAMETER_BLOCK;
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typedef struct BIOS_PARAMETER_BLOCK {
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USHORT BytesPerSector;
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UCHAR SectorsPerCluster;
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USHORT ReservedSectors;
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UCHAR Fats;
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USHORT RootEntries;
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USHORT Sectors;
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UCHAR Media;
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USHORT SectorsPerFat;
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USHORT SectorsPerTrack;
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USHORT Heads;
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ULONG HiddenSectors;
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ULONG LargeSectors;
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} BIOS_PARAMETER_BLOCK, *PBIOS_PARAMETER_BLOCK;
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// Define the boot sector
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typedef struct _PACKED_BOOT_SECTOR {
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UCHAR Jump[3]; // offset = 0x000 0
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UCHAR Oem[8]; // offset = 0x003 3
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PACKED_BIOS_PARAMETER_BLOCK PackedBpb; // offset = 0x00B 11
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UCHAR PhysicalDriveNumber; // offset = 0x024 36
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UCHAR Reserved; // offset = 0x025 37
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UCHAR Signature; // offset = 0x026 38
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UCHAR Id[4]; // offset = 0x027 39
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UCHAR VolumeLabel[11]; // offset = 0x02B 43
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UCHAR SystemId[8]; // offset = 0x036 54
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} PACKED_BOOT_SECTOR; // sizeof = 0x03E 62
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typedef PACKED_BOOT_SECTOR *PPACKED_BOOT_SECTOR;
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// Define the functions provided by this driver.
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BOOLEAN
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IsFatVolume(
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IN PPACKED_BOOT_SECTOR Buffer
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);
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VOID
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UnpackBiosParameterBlock(
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IN PPACKED_BIOS_PARAMETER_BLOCK Bios,
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OUT PBIOS_PARAMETER_BLOCK UnpackedBios
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);
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