IoCallDriver源碼剖析

 

IoCallDriver是一個宏：

#define IoCallDriver(a,b)   \        IofCallDriver(a,b)

顯然用的是IofCallDriver();

IofCallDriver()代碼如下：

NTSTATUSFASTCALLIofCallDriver(    IN PDEVICE_OBJECT DeviceObject,    IN OUT PIRP Irp    ){    if (pIofCallDriver != NULL) {        //        // This routine will either jump immediately to IovCallDriver or        // IoPerfCallDriver.        //        return pIofCallDriver(DeviceObject, Irp, _ReturnAddress());    }    return IopfCallDriver(DeviceObject, Irp);}

pIofCallDriver 好像是(在標頭檔定義)

extern PIO_CALL_DRIVER        pIofCallDriver;

PIO_CALL_DRIVER則是一個函數指標

typedefNTSTATUS(FASTCALL *PIO_CALL_DRIVER) (    IN      PDEVICE_OBJECT  DeviceObject,    IN OUT  PIRP            Irp,    IN      PVOID           ReturnAddress    );

 

再來說IopfCallDriver

NTSTATUSFORCEINLINEIopfCallDriver(    IN PDEVICE_OBJECT DeviceObject,    IN OUT PIRP Irp    )/*++Routine Description:    This routine is invoked to pass an I/O Request Packet (IRP) to another    driver at its dispatch routine.Arguments:    DeviceObject - Pointer to device object to which the IRP should be passed.    Irp - Pointer to IRP for request.Return Value:    Return status from driver's dispatch routine.--*/{    PIO_STACK_LOCATION irpSp;    PDRIVER_OBJECT driverObject;    NTSTATUS status;    //    // Ensure that this is really an I/O Request Packet.    //    ASSERT( Irp->Type == IO_TYPE_IRP );    //    // Update the IRP stack to point to the next location.
　　//可見Irp的那個數組標號越大表示越頂層裝置    //    Irp->CurrentLocation--;    if (Irp->CurrentLocation <= 0) {        KiBugCheck3( NO_MORE_IRP_STACK_LOCATIONS, (ULONG_PTR) Irp, 0, 0 );    }    irpSp = IoGetNextIrpStackLocation( Irp );    Irp->Tail.Overlay.CurrentStackLocation = irpSp;    //    // Save a pointer to the device object for this request so that it can    // be used later in completion.    //    irpSp->DeviceObject = DeviceObject;    //    // Invoke the driver at its dispatch routine entry point.    //    driverObject = DeviceObject->DriverObject;　　    //    // Prevent the driver from unloading.    // 用給定的驅動對象進行調用　　    status = driverObject->MajorFunction[irpSp->MajorFunction]( DeviceObject,                                                              Irp );    return status;}