How can the caller's process be identified in an ATL COM+ out-of-proc server application?

Question

I have an ATL service running as an out-of-proc server that has several COM classes that the clients are expected to be using. Because of a change in requirements, I need to be able to identify which process owns which instances of the objects. I'm trying to use some of the COM functions to find out this information but I can't find the right ones. CoGetCallContext only returns information about the user who called the method, not which process it came from. Same with CoQueryClientBlanket. What function can I use to find out this information?

Mia

Determine the Process ID of the Client Process communicating with a COM RPC Server – Carborundum

Thanks @RomanR., I thought it might be here but I didn't see it before. – Mia

You best bet is changing the interfaces so that when an object is being created the caller passes his id. – Abshier

Answer 1

I know that I'm 6.5 years late but just answering this in case anyone in the future needed it.

So there's a way to do this.... but through a private built-in COM interface, which is ICallingProcessInfo

Interface definition:

MIDL_INTERFACE("68C6A1B9-DE39-42C3-8D28-BF40A5126541")
ICallingProcessInfo : public IUnknown
{
public:
    virtual STDMETHOD(OpenCallerProcessHandle)(DWORD dwDesiredAccess, HANDLE* handle) = 0;
};

Usage:

HANDLE handle;
ComPtr<ICallingProcessInfo> callingProcessInfo; // ComPtr is from WRL, you can use the interface directly instead
CoGetCallContext(__uuidof(ICallingProcessInfo), (void**)callingProcessInfo.GetAddressOf());
callingProcessInfo->OpenCallerProcessHandle(PROCESS_QUERY_LIMITED_INFORMATION, &handle);

I tested this on a WinRT OOP Server but since WinRT Servers are just COM Servers it should work with normal COM Servers too

Chromaticity

Thanks! Although I've long since moved on from this project, hopefully it will be helpful to others in the future :-D – Mia