Windows driver development and windows driver development

Windows driver development and windows driver development

In the previous article "Windows driver development-4", we have completed hardware preparation. However, we do not have specific data operations, such as receiving read/write operations.

Before performing such operations in WDF, you must perform device I/O control to ensure data integrity.

We know that WDF development follows the "Footsteps" of IRPs ".

I/O Request Delivery Mechanic
I/O request type	UMDF delivery Mechanic	KMDF delivery Mechanic
Read	Queue	Queue
Write	Queue	Queue
Device I/O control	Queue	Queue
Internal device I/O control	Queue	Queue
Create	Queue	Queue or callback
Close	Callback	Callback
Cleanup	Callback	Callback

From the table, we can see that WDF uses the Queue mechanism during device I/O control.

Therefore, we need to provide queue support when adding devices.

  WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE(&ioQueueConfig,                                    WdfIoQueueDispatchParallel);    ioQueueConfig.EvtIoDeviceControl = EvtIoDeviceControl;    status = WdfIoQueueCreate(device,                         &ioQueueConfig,                         WDF_NO_OBJECT_ATTRIBUTES,                         WDF_NO_HANDLE);

(1) initialize queue Configuration

WDF_IO_QUEUE_CONFIG_INIT_DEFAULT_QUEUE

VOID WDF_IO_QUEUE_CONFIG_INIT_DEFAULT_QUEUE(  _Out_ PWDF_IO_QUEUE_CONFIG       Config,  _In_  WDF_IO_QUEUE_DISPATCH_TYPE DispatchType);

(2) Set callback events

Set the member variable value in the WDF_IO_QUEUE_CONFIG structure.

typedef struct _WDF_IO_QUEUE_CONFIG {  ULONG                                       Size;  WDF_IO_QUEUE_DISPATCH_TYPE                  DispatchType;  WDF_TRI_STATE                               PowerManaged;  BOOLEAN                                     AllowZeroLengthRequests;  BOOLEAN                                     DefaultQueue;  PFN_WDF_IO_QUEUE_IO_DEFAULT                 EvtIoDefault;  PFN_WDF_IO_QUEUE_IO_READ                    EvtIoRead;  PFN_WDF_IO_QUEUE_IO_WRITE                   EvtIoWrite;  PFN_WDF_IO_QUEUE_IO_DEVICE_CONTROL          EvtIoDeviceControl;  PFN_WDF_IO_QUEUE_IO_INTERNAL_DEVICE_CONTROL EvtIoInternalDeviceControl;  PFN_WDF_IO_QUEUE_IO_STOP                    EvtIoStop;  PFN_WDF_IO_QUEUE_IO_RESUME                  EvtIoResume;  PFN_WDF_IO_QUEUE_IO_CANCELED_ON_QUEUE       EvtIoCanceledOnQueue;  union {    struct {      ULONG NumberOfPresentedRequests;    } Parallel;  } Settings;  WDFDRIVER                                   Driver;} WDF_IO_QUEUE_CONFIG, *PWDF_IO_QUEUE_CONFIG;

(3) create a queue
WdfIoQueueCreate

NTSTATUS WdfIoQueueCreate(  [in]            WDFDEVICE              Device,  [in]            PWDF_IO_QUEUE_CONFIG   Config,  [in, optional]  PWDF_OBJECT_ATTRIBUTES QueueAttributes,  [out, optional] WDFQUEUE               *Queue);