[转]IoCallDriver实现

NTSTATUS
IoCallDriver(
    IN PDEVICE_OBJECT DeviceObject,
    IN OUT PIRP Irp
    )
{
    return IofCallDriver (DeviceObject, Irp);
}

NTSTATUS
FASTCALL
IofCallDriver(
    IN PDEVICE_OBJECT DeviceObject,
    IN OUT PIRP Irp
    )
{
    //
    // This routine will either jump immediately to IopfCallDriver, or rather
    // IovCallDriver.
    //
    return pIofCallDriver(DeviceObject, Irp);
}

 

NTSTATUS
FASTCALL
IopfCallDriver(
    IN PDEVICE_OBJECT DeviceObject,
    IN OUT PIRP Irp
    )

/*++

Routine Description:

    This routine is invoked to pass an I/O Request Packet (IRP) to another
    driver at its dispatch routine.

Arguments:

    DeviceObject - Pointer to device object to which the IRP should be passed.

    Irp - Pointer to IRP for request.

Return Value:

    Return status from driver's dispatch routine.

--*/

{
    PIO_STACK_LOCATION irpSp;
    PDRIVER_OBJECT driverObject;
    NTSTATUS status;

    //
    // Ensure that this is really an I/O Request Packet.
    //

    ASSERT( Irp->Type == IO_TYPE_IRP );

    //
    // Update the IRP stack to point to the next location.
    //
    Irp->CurrentLocation--;

    if (Irp->CurrentLocation <= 0) {
        KeBugCheckEx( NO_MORE_IRP_STACK_LOCATIONS, (ULONG_PTR) Irp, 0, 0, 0 );
    }

    irpSp = IoGetNextIrpStackLocation( Irp );
    Irp->Tail.Overlay.CurrentStackLocation = irpSp;

    //
    // Save a pointer to the device object for this request so that it can
    // be used later in completion.
    //

    irpSp->DeviceObject = DeviceObject;

    //
    // Invoke the driver at its dispatch routine entry point.
    //

    driverObject = DeviceObject->DriverObject;

    PERFINFO_DRIVER_MAJORFUNCTION_CALL(Irp, irpSp, driverObject);

    status = driverObject->MajorFunction[irpSp->MajorFunction]( DeviceObject,
                                                              Irp );

    PERFINFO_DRIVER_MAJORFUNCTION_RETURN(Irp, irpSp, driverObject);

    return status;
}