从虚拟音频驱动程序将音频数据发送到用户模式应用程序

Question

我当前的任务是将音频数据从虚拟音频驱动程序发送到用户模式应用程序。

首先，我需要从用户模式应用程序创建该虚拟音频驱动程序的实例...

请参阅下面的代码片段，

//Generating the device info
//That works
SetupDiGetClassDevs( &KSCATEGORY_AUDIO, NULL, NULL,  DIGCF_PRESENT|DIGCF_DEVICEINTERFACE );

//Enumerating device interface
//That works
SetupDiEnumDeviceInterfaces(dev_info, &DeviceInfoData, &KSCATEGORY_AUDIO, i, &did);

//Getting the path to device (pdd)
//That works
bRes = SetupDiGetDeviceInterfaceDetail(dev_info, &did, pdd, required_size, NULL, NULL);

//Handle to the device
//That works
HANDLE hHandle = CreateFile( pdd->DevicePath, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING,
            FILE_ATTRIBUTE_NORMAL, NULL);

//Passing the Handle
//That fails
//PData is the Out buffer where we get the driver sending value
bool bRc = DeviceIoControl ( hHandle,
                         (DWORD)IOCTL_SIOCTL_METHOD_OUT_DIRECT,  NULL, 0, &PData,
               sizeof( PData), &bytesReturned, NULL );

您能指出原因吗？

对于上面的用户模式应用程序，我曾经编写过一段 IOCTL 代码，如下所示...

NTSTATUS IoCtlHandler(PDEVICE_OBJECT pDeviceObject, PIRP Irp)
{
    PAGED_CODE();
    UINT dwDataSize = 0;
    PBYTE pReturnData ;

       pReturnData = (PBYTE)"IOCTL - Direct In I/O From Kernel Welcome to the world of   Portcl";
    dwDataSize = sizeof("IOCTL - Direct In I/O From Kernel! Welcome to the world of Portcl");

    //Point to a certain IRP location
     pIoStackIrp = IoGetCurrentIrpStackLocation(Irp);

     if(pIoStackIrp) 
     {

         switch(pIoStackIrp->Parameters.DeviceIoControl.IoControlCode)
         {
        //that ioctl  i pass inside the DeviceIoControl function
               case IOCTL_SIOCTL_METHOD_OUT_DIRECT:
             {
                 pOutputBuffer = NULL;
                 NtStatus = STATUS_UNSUCCESSFUL;

                 if(Irp->MdlAddress)
                 {
                                   pOutputBuffer = MmGetSystemAddressForMdlSafe(Irp-    >MdlAddress, NormalPagePriority);
                 }
                                                                                                          RtlCopyBytes(pOutputBuffer, pReturnData, dwDataSize);

                 break;
             }
         }
     }

     Irp->IoStatus.Information = dwDataSize;
     Irp->IoStatus.Status = NtStatus;

    //After all complete the IRP structure  
        //As it is a adapter driver we pass this information to handle by adapter itself
    NtStatus = PcDispatchIrp(pDeviceObject, Irp);

    return NtStatus;
}

请您指出我的错误。为了我的测试目的，我只是传递一个字符串（IOCTL - Direct In I/O From Kernel Welcome to Portcl 的世界”）到输出缓冲区稍后我将用音频数据替换它...为什么 deviceIoControl 失败，尽管我得到了在驱动程序中传递的字符串，但 bytesReturn 值始终作为随机值出现，而 bRes 值始终为 false ...