WDM驅動載入方式理解

標籤：

當PC得知有新裝置插入時，匯流排驅動會建立相應的物理驅動PDO，然後提示有新裝置插入，這時候調用相應Driver的AddDevice方法建立功能驅動FDO

下面是一個典型的AddDevice方法

#pragma PAGEDCODENTSTATUS HelloWDMAddDevice(IN PDRIVER_OBJECT DriverObject,                           IN PDEVICE_OBJECT PhysicalDeviceObject){     PAGED_CODE();    KdPrint(("Enter HelloWDMAddDevice\n"));    NTSTATUS status;    PDEVICE_OBJECT fdo;    UNICODE_STRING devName;    RtlInitUnicodeString(&devName,L"\\Device\\MyWDMDevice");    status = IoCreateDevice(        DriverObject,        sizeof(DEVICE_EXTENSION),        &(UNICODE_STRING)devName,        FILE_DEVICE_UNKNOWN,        0,        FALSE,        &fdo);    if( !NT_SUCCESS(status))        return status;    PDEVICE_EXTENSION pdx = (PDEVICE_EXTENSION)fdo->DeviceExtension;    pdx->fdo = fdo;    pdx->NextStackDevice = IoAttachDeviceToDeviceStack(fdo, PhysicalDeviceObject);    UNICODE_STRING symLinkName;    RtlInitUnicodeString(&symLinkName,L"\\DosDevices\\HelloWDM");    pdx->ustrDeviceName = devName;    pdx->ustrSymLinkName = symLinkName;    status = IoCreateSymbolicLink(&(UNICODE_STRING)symLinkName,&(UNICODE_STRING)devName);    if( !NT_SUCCESS(status))    {        IoDeleteSymbolicLink(&pdx->ustrSymLinkName);        status = IoCreateSymbolicLink(&symLinkName,&devName);        if( !NT_SUCCESS(status))        {            return status;        }    }    fdo->Flags |= DO_BUFFERED_IO | DO_POWER_PAGABLE;    fdo->Flags &= ~DO_DEVICE_INITIALIZING;    KdPrint(("Leave HelloWDMAddDevice\n"));    return STATUS_SUCCESS;}

細心的人也許會覺得這個方法的第二個參數PhysicalDeviceObject，即PDO，來的有些莫名其妙，沒有交代類型等

這個對象在inf可以指定它的類型，比如

ServiceType=1

WDM驅動載入方式理解