Efficiently build Android system service component

Question

I'm trying to extend Android's PackageManager functionalities modifying this file:

frameworks/base/services/core/java/com/android/server/pm/SELinuxMMAC.java

When I perform a make clean && make after editing the file and I start the emulator, the changes are there, but this takes too long even with the cache enabled. I tried using mmm framework/base but it does not seem to rebuild the services.core module.

Does anyone know a reliable method to modify a system service and then rebuild efficiently?

Answer 1

mmm and submodules

1. Create the new classes.dex for the services.core module:

   mmm frameworks/base/services/core
   

2. Creates the services.jar file including the services.core module that we just rebuilt:

   mmm frameworks/base/services
   

3. Creates the new system.img for the emulator:

   make snod
   

   If the emulator (or the device) is already running, you can use the new services.jar with:

   adb remount && adb sync && adb shell stop && adb shell start
   

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In fact mm and mmm do not check for modified submodules, so rebuilding the services module (step 2) without previously rebuilding the services.core (step 1) module is not enough.

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DEXPREOPT

If you see the message:

Warning: with dexpreopt enabled, you may need a full rebuild.

You have to turn off the dex preoptimization performing a make clean and then use the following flags in make and mm: WITH_DEXPREOPT=false and DISABLE_DEXPREOPT=true.