[wdmaudiodev] Re: Overriding IRP_MJ_DEVICE_CONTROL handling is possible?

  • From: AsHwAtH <itsmeash@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Mon, 9 Apr 2007 13:24:08 +0530

Nopes, you are on the right track.

You can override portcls IOCTL interface with user defined calls.

If in case you are not interested to perform any operation, you can
gracefully pass it to portcls by calling DispatchIRp call.

On 4/9/07, Don Bell <0dbell@xxxxxxxxx> wrote:


I am trying to find a way to add some custom IOCTL handling to a
miniport audio driver. The driver's DriverEntry() currently looks like
this:


extern "C" NTSTATUS DriverEntry(
  IN PDRIVER_OBJECT  DriverObject,
  IN PUNICODE_STRING RegistryPathName)
{
   NTSTATUS ntStatus = PcInitializeAdapterDriver(
                                       DriverObject,
                                       RegistryPathName,
                                       (PDRIVER_ADD_DEVICE)AddDevice);

  return ntStatus;
}

And I was thinking of adding a DispatchDeviceControl() like this:

extern "C" NTSTATUS DriverEntry(
  IN PDRIVER_OBJECT  DriverObject,
  IN PUNICODE_STRING RegistryPathName)
{
   NTSTATUS ntStatus = PcInitializeAdapterDriver(
                                       DriverObject,
                                       RegistryPathName,
                                       (PDRIVER_ADD_DEVICE)AddDevice);

  if(NT_SUCCESS(ntStatus))
  {
    DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] =

DeviceControlHandler;
  }
  return ntStatus;
}

Then, in DeviceControlHandler():

(1) Use IoGetCurrentIrpStackLocation() - to obtain current stack location.

(2) Handle it (i.e. the current IRP) if it's "mine" or pass it down
the stack for processing by using IoSkipCurrentIrpStackLocation() and
then calling IoCallDriver().

My questions is... Is this "legal"? That is, is the PortCls system
designed to handle such customization (i.e. mixing PortCls high-level
Pc* with Io*)?

The main reason I am asking such a trivial question is that while I
can make this appear to work, it may be in violation of some
fundamental principle in the PortCls system, which will trigger bugs
that could be a nightmare to debug.

Am I in for trouble in attempting to hack something like this into
PortCls?

Many thanks in advance,
Don
******************

WDMAUDIODEV addresses:
Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
Subscribe:    mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
Unsubscribe:  mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
Moderator:    mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx

URL to WDMAUDIODEV page:
http://www.wdmaudiodev.com/

Other related posts:

  1. Home
  2. wdmaudiodev
  3. Archive
  4. 04-2007