分层驱动---挂载设备对象事例

为了设备栈平衡,需要 IoSkipCurrentIrpStackLocation 或 IoCopyCurrentIrpStackLocationToNext

这个事例仅仅向下转发,没有做任何处理..所以IoSkipCurrentIrpStackLocation就好了.

这里把driver8挂载到drivertest  ..顶层是 driver8 ,所以即使是发给drivertest的irp也会先传给driver8

#define DEVICE_NAME			"\\Device\\DRIVER8_DeviceName"
#define SYMLINK_NAME		"\\DosDevices\\DRIVER8_DeviceName"
PRESET_UNICODE_STRING(usDeviceName, DEVICE_NAME);
PRESET_UNICODE_STRING(usSymlinkName, SYMLINK_NAME);

typedef struct{
	DEVICE_OBJECT *pTargetDevObj;

}DEVICE_EXTENSION;

#ifdef __cplusplus
extern "C" {
#endif
NTSTATUS DriverEntry(
    IN OUT PDRIVER_OBJECT   DriverObject,
    IN PUNICODE_STRING      RegistryPath
    )
{


	KdPrint(("DriverEntry 挂载例子..."));
    PDEVICE_OBJECT pdoDeviceObj = 0;
    NTSTATUS status = STATUS_UNSUCCESSFUL;
    pdoGlobalDrvObj = DriverObject;

    // Create the device object.
    if(!NT_SUCCESS(status = IoCreateDevice(
        DriverObject,
        sizeof(DEVICE_EXTENSION),
        &usDeviceName,
        FILE_DEVICE_UNKNOWN,
        FILE_DEVICE_SECURE_OPEN,
        FALSE,
        &pdoDeviceObj
        )))
    {
        // Bail out (implicitly forces the driver to unload).
        return status;
    };

    // Now create the respective symbolic link object
    if(!NT_SUCCESS(status = IoCreateSymbolicLink(
        &usSymlinkName,
        &usDeviceName
        )))
    {
        IoDeleteDevice(pdoDeviceObj);
        return status;
    }

    // NOTE: You need not provide your own implementation for any major function that
    //       you do not want to handle. I have seen code using DDKWizard that left the
    //       *empty* dispatch routines intact. This is not necessary at all!
    DriverObject->MajorFunction[IRP_MJ_CREATE] =
    DriverObject->MajorFunction[IRP_MJ_CLOSE] = DRIVER8_DispatchCreateClose;
    DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] = DRIVER8_DispatchDeviceControl;
    DriverObject->DriverUnload = DRIVER8_DriverUnload;
	DriverObject->MajorFunction[IRP_MJ_READ]=DRIVER8_DispatchRead;

	UNICODE_STRING ustrDeviceTest;
	RtlInitUnicodeString(&ustrDeviceTest,L"\\Device\\DRIVERTEST_DeviceName");

	DEVICE_OBJECT *pDeviceObject;
	FILE_OBJECT *pFileObject;
	NTSTATUS status2=IoGetDeviceObjectPointer(&ustrDeviceTest,FILE_ALL_ACCESS,&pFileObject,&pDeviceObject);
	if(!NT_SUCCESS(status2)){
		KdPrint(("IoGetDeviceObjectPointer failed"));
		ObDereferenceObject(pFileObject);
		return STATUS_SUCCESS;
	}

	DEVICE_EXTENSION *pDex=(DEVICE_EXTENSION*)pdoDeviceObj->DeviceExtension;


	DEVICE_OBJECT *pDeviceObjectAttD2S=IoAttachDeviceToDeviceStack(pdoDeviceObj,pDeviceObject);
	pDex->pTargetDevObj=pDeviceObjectAttD2S;//返回TargetDevice下面的低一层设备桟


	if (!pDeviceObjectAttD2S)
	{
		KdPrint(("fck !IoAttachDeviceToDeviceStack"));
		ObDereferenceObject(pFileObject);
		IoDeleteDevice(pDeviceObject);
		return STATUS_SUCCESS;
	}

	
	pdoDeviceObj->DeviceType=pDeviceObjectAttD2S->DeviceType;
	pdoDeviceObj->Characteristics=pDeviceObjectAttD2S->Characteristics;
	pdoDeviceObj->Flags&=~DO_DEVICE_INITIALIZING;
	pdoDeviceObj->Flags|=(pDeviceObjectAttD2S->Flags&(DO_DIRECT_IO | DO_BUFFERED_IO));
	

	ObDereferenceObject(pFileObject);
	KdPrint(("Attached finished "));



    return STATUS_SUCCESS;
}
#ifdef __cplusplus
}; // extern "C"
#endif

NTSTATUS DRIVER8_DispatchRead(
									 IN PDEVICE_OBJECT		DeviceObject,
									 IN PIRP					Irp
									 )
{

	KdPrint(("DRIVER8_DispatchRead"));
	NTSTATUS status = STATUS_SUCCESS;
// 	Irp->IoStatus.Status = status;
// 	Irp->IoStatus.Information = 0;
// 	IoCompleteRequest(Irp, IO_NO_INCREMENT);

	DEVICE_EXTENSION *pDex=(DEVICE_EXTENSION*)DeviceObject->DeviceExtension;
	IoSkipCurrentIrpStackLocation(Irp);
	status=IoCallDriver(pDex->pTargetDevObj,Irp);

	return status;
}