Just An Application

August 22, 2009

A Standalone Android Runtime: Application Installation

Filed under: Android, Java, Mobile Java, Standalone Android Runtime — Tags: , , , — Simon Lewis @ 7:25 am

It turns out that an application can be installed, such that it can subsequently be run, simply by placing the package containing it in the data app directory. On a device this would usually be the directory

    /data/app

When it is started by the SystemServer the PackageManagerService will scan this directory and find the package containing the application. It will then ask the Installer to install the application.

The Installer in the SystemServer is simply a proxy for the installd process which can be found here

    $(ANDROID_SRC)/frameworks/base/cmds/installd

It is responsible for creating the directories for the application being installed and for changing their ownership to that of the application. This requires root privilege or something like it which is why it is being done by a standlone process rather than in the context of the SystemServer process.

The proxy in the SystemServer communicates with installd using local sockets. Neither local sockets nor some of the functionality required by installd are available in standard Java but we can mimic enough that the installation of the application succeeds.


Copyright (c) 2009 By Simon Lewis. All Rights Reserved.

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