直接读写磁盘扇区

DDK示例中的代码。




NTSTATUS


FltReadSectors(


IN PDEVICE_OBJECT DeviceObject,


OUT PVOID Buffer,


IN ULONG Length,


IN LONGLONG ByteOffset,


IN BOOLEAN Wait


)


/*++




Routine Description:




This routine tries to read the data from the disk.




Arguments:




DeviceObject - the lower device in the stack


Buffer - the buffer which hold the data


Length - the data length want to read


ByteOffset - the data offset on the disk




Return Value:




NT Status is returned.




--*/


{


PIRP irp;


IO_STATUS_BLOCK iosb;


KEVENT event;


NTSTATUS status;




irp = IoBuildAsynchronousFsdRequest(IRP_MJ_READ, DeviceObject,


Buffer, Length, (PLARGE_INTEGER) &ByteOffset, &iosb);


if (!irp) {


return STATUS_INSUFFICIENT_RESOURCES;


}




if (Wait) {


KeInitializeEvent(&event, NotificationEvent, FALSE);


IoSetCompletionRoutine(irp, FltReadWriteSectorsCompletion,


&event, TRUE, TRUE, TRUE);




status = IoCallDriver(DeviceObject, irp);


if (STATUS_PENDING == status) {


KeWaitForSingleObject(&event, Executive, KernelMode, FALSE, NULL);


status = iosb.Status;


}


} else {


IoSetCompletionRoutine(irp, FltReadWriteSectorsCompletion,


NULL, TRUE, TRUE, TRUE);


irp->UserIosb = NULL;


status = IoCallDriver(DeviceObject, irp);


}




return status;


}




NTSTATUS


FltWriteSectors(


IN PDEVICE_OBJECT DeviceObject,


IN PVOID Buffer,


IN ULONG Length,


IN LONGLONG ByteOffset,


IN BOOLEAN Wait


)


/*++




Routine Description:




This routine tries to write the data to the disk.




Arguments:




DeviceObject - the lower device in the stack


Buffer - the buffer which hold the data


Length - the data length want to read


ByteOffset - the data offset on the disk




Return Value:




NT Status is returned.




--*/


{


PIRP irp;


IO_STATUS_BLOCK iosb;


KEVENT event;


NTSTATUS status;




irp = IoBuildAsynchronousFsdRequest(IRP_MJ_WRITE, DeviceObject,


Buffer, Length, (PLARGE_INTEGER) &ByteOffset, &iosb);


if (!irp) {


return STATUS_INSUFFICIENT_RESOURCES;


}




if (Wait) {


KeInitializeEvent(&event, NotificationEvent, FALSE);


IoSetCompletionRoutine(irp, FltReadWriteSectorsCompletion,


&event, TRUE, TRUE, TRUE);




status = IoCallDriver(DeviceObject, irp);


if (STATUS_PENDING == status) {


KeWaitForSingleObject(&event, Executive, KernelMode, FALSE, NULL);


status = iosb.Status;


}


} else {


IoSetCompletionRoutine(irp, FltReadWriteSectorsCompletion,


NULL, TRUE, TRUE, TRUE);


irp->UserIosb = NULL;


status = IoCallDriver(DeviceObject, irp);


}




return status;


}




NTSTATUS


FltReadWriteSectorsCompletion(


IN PDEVICE_OBJECT DeviceObject,


IN PIRP Irp,


IN PVOID Context


)


/*++


Routine Description:


A completion routine for use when calling the lower device objects to


which our filter deviceobject is attached.




Arguments:




DeviceObject - Pointer to deviceobject


Irp - Pointer to a PnP Irp.


Context - NULL or PKEVENT


Return Value:




NT Status is returned.




--*/


{


PMDL mdl;




UNREFERENCED_PARAMETER(DeviceObject);




//


// Free resources


//




if (Irp->AssociatedIrp.SystemBuffer && (Irp->Flags & IRP_DEALLOCATE_BUFFER)) {


ExFreePool(Irp->AssociatedIrp.SystemBuffer);


}




while (Irp->MdlAddress) {


mdl = Irp->MdlAddress;


Irp->MdlAddress = mdl->Next;


MmUnlockPages(mdl);


IoFreeMdl(mdl);


}




if (Irp->PendingReturned && (Context != NULL)) {


*Irp->UserIosb = Irp->IoStatus;


KeSetEvent((PKEVENT) Context, IO_DISK_INCREMENT, FALSE);


}




IoFreeIrp(Irp);




//


// Don't touch irp any more


//


return STATUS_MORE_PROCESSING_REQUIRED;


}