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181 lines
5 KiB
C
181 lines
5 KiB
C
/*
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* COPYRIGHT: See COPYING in the top level directory
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* PROJECT: ReactOS File System Recognizer
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* FILE: drivers/filesystems/fs_rec/fat.c
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* PURPOSE: FAT Recognizer
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* PROGRAMMER: Alex Ionescu (alex.ionescu@reactos.org)
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* Eric Kohl
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*/
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/* INCLUDES *****************************************************************/
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#include "fs_rec.h"
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#define NDEBUG
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#include <debug.h>
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/* FUNCTIONS ****************************************************************/
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BOOLEAN
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NTAPI
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FsRecIsFatVolume(IN PPACKED_BOOT_SECTOR PackedBootSector)
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{
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BIOS_PARAMETER_BLOCK Bpb;
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BOOLEAN Result = TRUE;
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PAGED_CODE();
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RtlZeroMemory(&Bpb, sizeof(BIOS_PARAMETER_BLOCK));
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/* Unpack the BPB and do a small fix up */
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FatUnpackBios(&Bpb, &PackedBootSector->PackedBpb);
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if (Bpb.Sectors) Bpb.LargeSectors = 0;
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/* Recognize jump */
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if ((PackedBootSector->Jump[0] != 0x49) &&
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(PackedBootSector->Jump[0] != 0xE9) &&
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(PackedBootSector->Jump[0] != 0xEB))
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{
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/* Fail */
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Result = FALSE;
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}
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else if ((Bpb.BytesPerSector != 128) &&
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(Bpb.BytesPerSector != 256) &&
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(Bpb.BytesPerSector != 512) &&
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(Bpb.BytesPerSector != 1024) &&
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(Bpb.BytesPerSector != 2048) &&
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(Bpb.BytesPerSector != 4096))
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{
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/* Fail */
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Result = FALSE;
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}
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else if ((Bpb.SectorsPerCluster != 1) &&
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(Bpb.SectorsPerCluster != 2) &&
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(Bpb.SectorsPerCluster != 4) &&
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(Bpb.SectorsPerCluster != 8) &&
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(Bpb.SectorsPerCluster != 16) &&
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(Bpb.SectorsPerCluster != 32) &&
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(Bpb.SectorsPerCluster != 64) &&
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(Bpb.SectorsPerCluster != 128))
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{
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/* Fail */
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Result = FALSE;
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}
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else if (!Bpb.ReservedSectors)
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{
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/* Fail */
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Result = FALSE;
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}
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else if (!(Bpb.Sectors) && !(Bpb.LargeSectors))
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{
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/* Fail */
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Result = FALSE;
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}
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else if ((Bpb.Media != 0x00) &&
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(Bpb.Media != 0x01) &&
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(Bpb.Media != 0xf0) &&
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(Bpb.Media != 0xf8) &&
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(Bpb.Media != 0xf9) &&
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(Bpb.Media != 0xfa) &&
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(Bpb.Media != 0xfb) &&
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(Bpb.Media != 0xfc) &&
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(Bpb.Media != 0xfd) &&
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(Bpb.Media != 0xfe) &&
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(Bpb.Media != 0xff))
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{
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/* Fail */
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Result = FALSE;
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}
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else if ((Bpb.SectorsPerFat) && !(Bpb.RootEntries))
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{
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/* Fail */
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Result = FALSE;
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}
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/* Return the result */
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return Result;
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}
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NTSTATUS
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NTAPI
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FsRecVfatFsControl(IN PDEVICE_OBJECT DeviceObject,
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IN PIRP Irp)
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{
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PIO_STACK_LOCATION Stack;
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NTSTATUS Status;
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PDEVICE_OBJECT MountDevice;
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PPACKED_BOOT_SECTOR Bpb = NULL;
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ULONG SectorSize;
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LARGE_INTEGER Offset = {{0, 0}};
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BOOLEAN DeviceError = FALSE;
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PAGED_CODE();
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/* Get the I/O Stack and check the function type */
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Stack = IoGetCurrentIrpStackLocation(Irp);
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switch (Stack->MinorFunction)
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{
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case IRP_MN_MOUNT_VOLUME:
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/* Assume failure */
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Status = STATUS_UNRECOGNIZED_VOLUME;
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/* Get the device object and request the sector size */
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MountDevice = Stack->Parameters.MountVolume.DeviceObject;
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if (FsRecGetDeviceSectorSize(MountDevice, &SectorSize))
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{
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/* Try to read the BPB */
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if (FsRecReadBlock(MountDevice,
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&Offset,
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512,
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SectorSize,
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(PVOID)&Bpb,
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&DeviceError))
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{
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/* Check if it's an actual FAT volume */
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if (FsRecIsFatVolume(Bpb))
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{
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/* It is! */
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Status = STATUS_FS_DRIVER_REQUIRED;
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}
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}
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/* Free the boot sector if we have one */
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ExFreePool(Bpb);
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}
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else
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{
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/* We have some sort of failure in the storage stack */
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DeviceError = TRUE;
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}
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/* Check if we have an error on the stack */
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if (DeviceError)
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{
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/* Was this because of a floppy? */
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if (MountDevice->Characteristics & FILE_FLOPPY_DISKETTE)
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{
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/* Let the FS try anyway */
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Status = STATUS_FS_DRIVER_REQUIRED;
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}
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}
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break;
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case IRP_MN_LOAD_FILE_SYSTEM:
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/* Load the file system */
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Status = FsRecLoadFileSystem(DeviceObject,
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L"\\Registry\\Machine\\System\\CurrentControlSet\\Services\\fastfat");
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break;
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default:
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/* Invalid request */
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Status = STATUS_INVALID_DEVICE_REQUEST;
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}
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/* Return Status */
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return Status;
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}
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/* EOF */
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