Doesn't work without root

[s1341]

It appears that neither the service nor the client work without root.... Is there a way to register the service so that it can work without root?

[mirfatif]

I haven't tested this NDK code but addService in Java is restricted by SELinux policies. Even ADB shell doesn't have the rights.

Also both addService and getService are hidden APIs i.e. meant to be used only by Android framework.

Also at least user apps cannot get a service added with the default SELinux context. You'll see SELinux denial something like:

avc: denied  { find } for s=untrusted_app t=default_android_service c=service_manager

So root seems to be the only option.

Edit:
Better explanation: lakinduboteju/AndroidNdkBinderExamples#3 (comment)