IoCallDriver source code analysis

 

IoCallDriver is a macro:

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

Apparently, IofCallDriver () is used ();

The IofCallDriver () code is as follows:

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 seems to be (defined in the header file)

extern PIO_CALL_DRIVER        pIofCallDriver;

PIO_CALL_DRIVER is a function pointer.

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

 

IopfCallDriver

NTSTATUSFORCEINLINEIopfCallDriver (IN PDEVICE_OBJECT DeviceObject, in out pirp)/* ++ 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 shoshould 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.
// The larger the array label of the visible Irp indicates the higher the top-layer device // 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. // call status = driverObject-> MajorFunction [irpSp-> MajorFunction] (DeviceObject, Irp); return status ;}