Android Platform Debugging and Development
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This document provides an overview and agenda for a presentation on Android platform debugging and development. It covers debugging architecture basics, setting up a development environment in Android Studio, tools for observing and monitoring apps and frameworks, interfacing with core Android components, working with AOSP sources, and dynamic data collection techniques like logging, strace, ftrace, and perf. Symbolic debugging with gdb/gdbserver and challenges with systrace/atrace are also discussed.
![11
/frameworks/base/services/java/...
/frameworks/base/services/jni/
/hardware/libhardware/
/device/[MANUF.]/[DEVICE]
/sdk/emulator/
Kernel or module
/frameworks/base/core/...
AOSP-provided
ASL
Manuf.-provided
Manuf. license
Manuf.-provided
GPL-license](https://image.slidesharecdn.com/android-platform-debug-dev-clean-160803-160803214725/85/Android-Platform-Debugging-and-Development-11-320.jpg)
![18
● Creating AOSP project files for Studio:
[aosp]$ make idegen && development/tools/idegen/idegen.sh
● Sometimes you also need to fix an issue with
"res.java":
[aosp]$ cd out/target/product/generic/obj/GYP/shared_intermediates
[aosp]$ mv res.java res.j && croot](https://image.slidesharecdn.com/android-platform-debug-dev-clean-160803-160803214725/85/Android-Platform-Debugging-and-Development-18-320.jpg)
![38
6.6. JNI debugging
$ prebuilts/gcc/linuxx86/arm/armeabi4.7/bin/armeabigdb
(gdb) target remote localhost:2345
(gdb) file out/target/product/msm8960/symbols/system/bin/app_process
(gdb) set solibabsoluteprefix out/target/product/msm8960/symbols/
(gdb) set solibsearchpath out/target/product/msm8960/symbols/system/lib/
(gdb) b com_android_server_OpersysService.cpp:70
(gdb) cont
Continuing.
root@android:/ # service call opersys 2 s16 adfasd
[New Thread 576]
[Switching to Thread 576]
Breakpoint 1, write_native (env=0x5c94ad40, clazz=<value optimized out>,
ptr=<value optimized out>, buffer=0xa4f00005)
at frameworks/base/services/jni/com_android_server_OpersysService.cpp:72
72 if (dev == NULL) {
(gdb)](https://image.slidesharecdn.com/android-platform-debug-dev-clean-160803-160803214725/85/Android-Platform-Debugging-and-Development-38-320.jpg)
![47
# atrace help
usage: atrace [options] [categories...]
options include:
a appname enable applevel tracing for a comma separated list of
cmdlines
b N use a trace buffer size of N KB
c trace into a circular buffer
k fname,... trace the listed kernel functions
n ignore signals
s N sleep for N seconds before tracing [default 0]
t N trace for N seconds [defualt 5]
z compress the trace dump
async_start start circular trace and return immediatly
async_dump dump the current contents of circular trace buffer
async_stop stop tracing and dump the current contents of circular
trace buffer
list_categories
list the available tracing categories](https://image.slidesharecdn.com/android-platform-debug-dev-clean-160803-160803214725/85/Android-Platform-Debugging-and-Development-47-320.jpg)
Android Platform Debugging and Development
- 1. 1 Android Platform Debugging and Development AnDevCon Boston 2016 Karim Yaghmour @karimyaghmour karim.yaghmour@opersys.com
- 2. 2 These slides are made available to you under a Creative Commons Share- Alike 3.0 license. The full terms of this license are here: https://creativecommons.org/licenses/by-sa/3.0/ Attribution requirements and misc., PLEASE READ: ● This slide must remain as-is in this specific location (slide #2), everything else you are free to change; including the logo :-) ● Use of figures in other documents must feature the below “Originals at” URL immediately under that figure and the below copyright notice where appropriate. ● You are free to fill in the “Delivered and/or customized by” space on the right as you see fit. ● You are FORBIDEN from using the default “About” slide as-is or any of its contents. ● You are FORBIDEN from using any content provided by 3rd parties without the EXPLICIT consent from those parties. (C) Copyright 2013-2016, Opersys inc. These slides created by: Karim Yaghmour Originals at: www.opersys.com/community/docs Delivered and/or customized by
- 3. 3 About ● Author of: ● Introduced Linux Trace Toolkit in 1999 ● Originated Adeos and relayfs (kernel/relay.c) ● Ara Android Arch Oversight ● Training, Custom Dev, Consulting, ...
- 4. 4 Agenda 1. Architecture Basics 2. Development environment 3. Observing and monitoring 4. Interfacing with the framework 5. Working with the AOSP sources 6. Symbolic debugging 7. Detailed dynamic data collection 8. Benchmarking 9. Summing up
- 5. 5 1. Architecture Basics ● Hardware used to run Android ● AOSP ● Binder ● System Services ● HAL
- 6. 6
- 7. 7
- 8. 8
- 9. 9
- 10. 10
- 11. 11 /frameworks/base/services/java/... /frameworks/base/services/jni/ /hardware/libhardware/ /device/[MANUF.]/[DEVICE] /sdk/emulator/ Kernel or module /frameworks/base/core/... AOSP-provided ASL Manuf.-provided Manuf. license Manuf.-provided GPL-license
- 12. 12 2. Development Environment ● Host / Target setup ● IDE / Editor ● Android Studio setup
- 13. 13 2.1. Host / Target setup
- 14. 14
- 15. 15 2.2. IDE / Editor Logos belong to their respective owners. This slide isn't CC-BY-SA.
- 16. 16 2.3. Android Studio Setup ● Preparation ● Project importing ● Browsing the sources
- 17. 17 2.3.1. Preparation ● AOSP Basics: ● Get AOSP ... from Google or otherwise ● Extract if needed ● Configure, build, etc. ● Android Studio: ● Get Android Studio from developer.android.com ● Extract ● Start and update and if needed
- 18. 18 ● Creating AOSP project files for Studio: [aosp]$ make idegen && development/tools/idegen/idegen.sh ● Sometimes you also need to fix an issue with "res.java": [aosp]$ cd out/target/product/generic/obj/GYP/shared_intermediates [aosp]$ mv res.java res.j && croot
- 19. 19 2.3.2. Project importing ● Start Android Studio: ● Choose "Open an Existing Android Studio Project" ● Select android.ipr from AOSP ● Let it finish indexing ● To force framework detection -- if no auto-detect: ● Close Studio ● Restart Studio ● Click on "Framework Detected" bubble
- 20. 20 ● Edit packages/apps/Launcher/src/com/android/launcher 2/DragLayer.java and modify: private boolean isLayoutRtl() { ● to public boolean isLayoutRtl() { ● Now: right-click on project and select "Refresh" ● It might still show "x" on some parts until it's done rebuilding the project
- 21. 21 2.3.3. Browsing the sources ● Right-click object type to be taken to declaration ● Browse classes through “Structure” ● Right-click "Find Usages" ● Toggle open files (Alt-left, Alt-right) ● Many other shortcuts, see: https://developer.android.com/sdk/installing/studio-tips.htm ● Issues: ● Can't compile with Studio ... still need “make” ● For Java only
- 22. 22 3. Observing and Monitoring ● Native ● Framework ● Overall ● Apps / Add-ons
- 23. 23 3.1. Native ● schedtop ● librank ● procmem ● procrank ● showmap ● latencytop
- 24. 24 3.2. Framework ● dumpsys ● service
- 25. 25 3.3 Overall ● logcat ● dumpstate / bugreport ● watchprop / getprop
- 26. 26
- 27. 27 3.4. Apps / Add-ons ● Google Play: ● Process Manager ● Process Monitor ● Task Manager ● Process Tracker ● ...
- 29. 29 4. Interfacing With the Framework ● start / stop ● service call ● am ● pm ● wm ● svc ● monkey ● setprop ● raidl
- 30. 30 5. Working with the AOSP Sources ● You really need to check build/envsetup.sh ● Some tricks: ● godir ● croot ● mm ● m ● jgrep ● cgrep ● resgrep ● It takes time to wrap your head around the tree
- 31. 31 6. Symbolic Debugging - basics
- 32. 32 6.1. Studio / Monitor integration ● Start Studio ● Start Monitor ● ("Android" icon on toolbar) ● Each process has a separate host-side socket ● Select the process you want to debug: ● It'll get port 8700
- 33. 33 ● Go back to Studio: ● Run->Edit Configurations->"+" ● Remote->Port: 8700 ● Apply & Debug ● Go back to Monitor: ● Check that the little green bug is beside your process in ddms ● You're now ready to debug
- 34. 34
- 35. 35 6.2. Debugging multiple processes ● Select process in Monitor ● Go back to Studio and start a new debugging session ● Each process will now have a green bug beside it
- 36. 36 6.4. gdbserver - target side ● AOSP already takes care of debug: ● “-g” flag added to all native binaries ● Unstripped binaries in out/target/product/.../symbols/... ● Attaching to running process # gdbserver attach locahost:2345 30 ● Start app for debugging with gdbserver prepended # gdbserver localhost:2345 service list ● Forward the port on the host: $ adb forward tcp:2345 tcp:2345
- 37. 37 6.5. gdb - host side ● Load file **FIRST** and then attach on host side $ prebuilts/gcc/linuxx86/arm/armeabi4.7/bin/armeabigdb GNU gdb (GDB) 7.3.1gg2 Copyright (C) 2011 Free Software Foundation, Inc. ... (gdb) file out/target/product/generic/symbols/system/bin/service (gdb) target remote localhost:2345 (gdb) b main Cannot access memory at address 0x0 Breakpoint 1 at 0x2a00146c: file frameworks/native/cmds/service/service.cpp, line 59. (gdb) cont Continuing. warning: Could not load shared library symbols for 11 libraries, e.g. /system/bin/linker. ... Breakpoint 1, main (argc=2, argv=0xbe882b74) at frameworks/native/cmds/service/service.cpp:59 59 { (gdb) n 60 sp<IServiceManager> sm = defaultServiceManager(); (gdb) n 59 { (gdb) n 60 sp<IServiceManager> sm = defaultServiceManager(); (gdb) n 61 fflush(stdout);
- 39. 39 6.7. JTAG ● Requires hardware device ● Sometimes interfaces with gdb ● Not Android specific ● Some allow transparent kernel/user-space debug ● Don't know of any that go all the way up to Dalvik
- 40. 40 7. Detailed Dynamic Data Collection ● Logging ● strace ● ftrace ● perf
- 41. 41 7.1. Logging ● logcat is the most rapid/consistent way to observe dynamic behavior. ● Trivial to add instrumentation points ● It just works ...
- 42. 42 7.2. strace ● Same as Linux ● Use man page if need be
- 43. 43 7.3. ftrace ● With 4.1, Google introduced systrace/atrace ● systrace is a Python script running on host side ● atrace is native Android binary ● systrace calls atrace via ADB ● atrace uses ftrace to capture kernel events ● Stack instrumented to feed events to ftrace ● Google's doc: ● https://developer.android.com/tools/help/systrace.html ● https://developer.android.com/tools/debugging/systrace.html
- 44. 44
- 45. 45 ... trouble is ... ● Finicky -- notes from my attempts with 4.3: ● I can't get it to work !*!@#$&!#*$! ● Default goldfish kernel doesn't have ftrace ● Able to build ftrace-enabled kernel for goldfish ● Can trace that system ... so long as I don't use atrace/systrace ... WTF1? ● Not all Android kernels have ftrace enabled ● Generates HTML file that can only be read by Chrome ... it doesn't work in Firefox. NIH? 1: The AOSP sources define WTF as “What a Terrible Failure”. We trust they've done their research.
- 46. 46 ... still ... ● Have a look at these files: ● /external/chromium-trace/systrace.py ● /frameworks/native/cmds/atrace ● /frameworks/base/core/java/android/os/Trace.java ● /erameworks/native/include/utils/Trace.h ● /system/core/include/cutils/trace.h ● /frameworks/native/libs/utils/Trace.cpp ● Look for: ● ATRACE* in c/cpp files ● Trace.traceBegin()/trace.traceEnd() in Java files
- 49. 49 7.3. perf on Android on ARM
- 51. 51 0xbench AnTuTu Passmark Vellamo Geekbench2 SunSpider GLBenchmakr Quadrant Standard Edition Linpack Neocore 3DMark Epic Citadel Androbench CF-bench SD Tools RL Benchmark: SQL Benchmark & Tunning A1 SD Bench Quick Benchmark Lite 3DRating benchmark Smartbench 2011 NenaMark Rightware Browsermark An3DBenchXL CaffeineMark NBench Methanol AndEBench SmartBench 2012 RealPi
- 52. 52 ● Works relatively well: ● logcat ● Studio / Monitor ● Framework tools ● Works ok: ● gdb/gdbserver ● native tools ● ftrace ● Finicky: ● systrace/atrace ● perf 9. Summing Up
- 53. 53 10. Loose ends ● debuggerd ● tombstones ● anr traces