SystemTap for Android

This repository contains a collection of scripts, tools, and sourcecode to build, install and run SystemTap on Android. For further information about SystemTap I would appreciate you to read the documentation published by the official SystemTap project [1].

Requirments

• Before you can start, you have to clone the submodules. Just run two commands:

  git submodule init

  git submodule upate

Building SystemTap

To be able to compile your systemtap scripts for android, just start the buildscript:

./build.sh

It automatically configures, build and installs systemtap for you. You can find this installation in the installed directory. It is independet from any other installation on your system. The script builds the arm binaries as well. They are located at src/android_binaries.

Setting up a device config

Before you can compile your stap script into a kernel module. You have to create a configuration for the target platform. So far a configuration consists of a path to the kernel sourcetree.

To create such a configuration write the path in a textfile named <device>.conf and place it under the config directory. Here is an example for the Samsung Galaxy Nexus:

omap.conf, contents:

KERNEL_ARCH=arm

KERNEL_SRC=/path/to/my/kernel/omap

Compile a script for android

Ensure that you have created a configuration for your device under conf/ and the kernel tree is prepared for compiling modules. Your script should be located in the scripts directory. Make sure you have an convenient toolchain in your PATH, e.g. the Android prebuilt one [2] or the one from MentorGraphics [3]. To start compilation: ./build_module.sh <script>

Where <devicename specifies the configuration to be used and <script> the systemtap script. Important: Omit the filename extension from both parameters.

The compiled script is located in modules/<devicename>/.

Run a compiled script (aka kernel module) on android

First you need to install the SystemTap Android Application located android-app on your device. It is a Eclipse project. So import it to Eclipse and install it on your device. (Note: You have to create a library project for SherlockActionbar aswell. A tarball containing the sources is located in android-app/.) Now place the compiled script on the sdcard under the /sdcard/systemtap/modules/ directory. Just start the android app, select the module and start it. :-) In addition, to the manual way you can transfer (and control as well) SystemTap via wifi. So, you may have a look at the following section.

Transfer a module to a device via wifi

1. If you haven't build stapandroid so far, run

   make -C tools/stapandroid

2. To transfer a module run the following command

   ./tools/stapandroid/stapandroid [-p <port>] <ip address/hostname> send <path to module>

The tools supports further commands like

• start
• stop
• delete
• list

Tools

The tools subdirectory contains two tools. First, two programs to extract and pack boot images for android. They are located in tools/bootimg. Second, a tool to remote control an android device running the systemtapp application. It is called stapandroid. As presented in the previous section it can execute several commands.

Both directories contain makefiles to simplify the build process. A simple make -C tools/<directory>/ will do. There are targets to install/uninstall the binaries on your system. They will ask for the root password inorder to install the binaries in /usr/local/bin.

Sources

• [1] http://sourceware.org/systemtap/documentation.html
• [2] https://android.googlesource.com/platform/prebuilt
• [3] http://www.mentor.com/embedded-software/sourcery-tools/sourcery-codebench/editions/lite-edition/