Manual COM Loading

ComUtils.cs

public static class ComUtils
{
    private delegate int DllGetClassObject(ref Guid clsid, ref Guid iid, out nint classFactoryPtr);
    private delegate void CreateInstance(nint self, nint pUnkOuter, ref Guid riid, out nint ppvObjectPtr);

    public static nint Load(string library)
    {
        Guid exceptionProfilerGuid = new Guid("805A308B-061C-47F3-9B30-F785C3186E82");
        Guid iclassFactoryGuid = new Guid("00000001-0000-0000-c000-000000000046");
        Guid iCorProfilerCallback8Guid = new Guid("5BED9B15-C079-4D47-BFE2-215A140C07E0");

        // Load profilers library (dlopen on linux)
        NativeLibrary.TryLoad(library, typeof(Segfault).Assembly, DllImportSearchPath.AssemblyDirectory, out nint handle);
        Debug.Assert(nint.Zero != handle);

        // Get pointer to method DllGetClassObject (dlsym on linux)
        nint methodHandle = NativeLibrary.GetExport(handle, "DllGetClassObject");
        Debug.Assert(nint.Zero != methodHandle);

        // Cast pointer to DllGetClassObject delegate
        DllGetClassObject dllGetClassObject = Marshal.GetDelegateForFunctionPointer<DllGetClassObject>(methodHandle);
        Debug.Assert(dllGetClassObject != null);

        // Call DllGetClassObject to query the IClassFactory interface that can create instances of Exception Profiler
        dllGetClassObject(ref exceptionProfilerGuid, ref iclassFactoryGuid, out nint classFactoryPtr);
        Debug.Assert(nint.Zero != classFactoryPtr);

        // Since we can't use COM marshalling on Linux, we need to manually get the CreateInstance method pointer from the virtual table
        nint vtablePtr = Marshal.ReadIntPtr(classFactoryPtr);
        nint createInstancePtr = vtablePtr + nint.Size * 3;
        CreateInstance createInstance = Marshal.GetDelegateForFunctionPointer<CreateInstance>(Marshal.ReadIntPtr(createInstancePtr));
        Debug.Assert(createInstance != null);

        // Create instance of profiler, which implements ICoreProfilerCallback8 interface
        createInstance(nint.Zero, ref iCorProfilerCallback8Guid, out nint ppvObjectPtr);
        Debug.Assert(nint.Zero != ppvObjectPtr);
        
        return ppvObjectPtr;

        // Free library
        // NativeLibrary.Free(handle);
    }
}