I am working my personal project and making some framework changes in Android OS code (AOSP). I want to write/read from a single file before an app is launched. I am making changes in framework/base/core/java/android/app/applications/ActivityThread.java, where it launches activity to run the app.
Each app is launched as a separate process and android expects me to add permission in AndroidManifest.xml, but I am not reading/writing file from the app, I am reading from the framework, before the app is launched.
Is there any way to create a single file which can be used by all users in ActivityThread?
Framework code running in app's process haven't any special privileges. Your need to put such code somewhere in system services.