获得FDO by name

NTSTATUS            ntStatus = STATUS_SUCCESS;   
    PDEVICE_OBJECT  DeviceObject = NULL;   
    PFILE_OBJECT        FileObject = NULL;     
    ntStatus = IoGetDeviceObjectPointer(pObjectName,FILE_ALL_ACCESS,&FileObject,&DeviceObject);   
    if(!NT_SUCCESS(ntStatus))   
    {   
        KdPrint(("IoGetDeviceObjectPointer Failed,ntStatus = 0x%08lX\n",ntStatus));   
        goto _EXIT0_;   
    }   
    KdPrint(("IoGetDeviceObjectPointer succeed!\n"));   

    DeviceObject = IoGetLowerDeviceObject(DeviceObject);   
    if(!DeviceObject)   
    {   
        KdPrint(("IoGetLowerDeviceObject Failed,ntStatus = 0x%08lX!\n",ntStatus));   
        ntStatus = STATUS_UNSUCCESSFUL;   
        goto _EXIT1_;   
    }   

    while(!(DeviceObject->Flags & DO_BUS_ENUMERATED_DEVICE))   
    {   
        ObDereferenceObject(DeviceObject);   
        DeviceObject = IoGetLowerDeviceObject(DeviceObject);   
        if(!DeviceObject)   
        {   
            ObDereferenceObject(FileObject);   
            ntStatus = STATUS_UNSUCCESSFUL;   
            goto _EXIT1_;   
        }    
    } 
照例pdo设备都会在Flags中设置DO_BUS_ENUMERATED_DEVICE，这也是判断PDO和FDO的标准之一


The IoGetLowerDeviceObject routine returns a pointer to the next-lower-level device object on the driver stack.

Ntifs.h (include Ntifs.h)
<= DISPATCH_LEVEL