调试Android NDK本机应用程序

Question

I'm trying to debug and step through an Android application that segfaults. I've tried ndk-gdb , but with little luck. I've also referred to Android NDK Debugging without being able to debug my app.

When I try ndk-gdb --start , and I get:

$ ndk-gdb --start --verbose
Android NDK installation path: /opt/android-ndk-r7
Using default adb command: /opt/android-sdk-linux/platform-tools/adb
ADB version found: Android Debug Bridge version 1.0.29
Using final ADB command: '/opt/android-sdk-linux/platform-tools/adb'
Using auto-detected project path: .
Found package name: com.example.native_plasma
ABIs targetted by application: armeabi armeabi-v7a
Device API Level: 10
Device CPU ABIs: armeabi-v7a armeabi
Compatible device ABI: armeabi-v7a
Found debuggable flag: true
Found device gdbserver: /data/data/com.example.native_plasma/lib/gdbserver
Using gdb setup init: ./libs/armeabi-v7a/gdb.setup
Using toolchain prefix: /opt/android-ndk-r7/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-
Using app out directory: ./obj/local/armeabi-v7a
Found data directory: '/data/data/com.example.native_plasma'
Found first launchable activity: android.app.NativeActivity
Launching activity: com.example.native_plasma/android.app.NativeActivity
## COMMAND: /opt/android-sdk-linux/platform-tools/adb shell am start -n com.example.native_plasma/android.app.NativeActivity
Starting: Intent { cmp=com.example.native_plasma/android.app.NativeActivity }
## COMMAND: /opt/android-sdk-linux/platform-tools/adb shell sleep 2
Found running PID: 0
ERROR: Could not extract PID of application on device/emulator.
       Weird, this probably means one of these:

         - The installed package does not match your current manifest.
         - The application process was terminated.

       Try using the --verbose option and look at its output for details.

This indicates that the application segfaulted more less, but I don't know how to set a breakpoint here since gdb never actually gives a prompt.

I also tried this command:

$ ../../toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-addr2line -f -e  libs/armeabi/libnative-plasma.so 
bedb2330
??
??:0

I have debug symbols I believe.

• ndk-build -BV=1 APP_OPTIM=debug
• Android.mk in jni/ has LOCAL_CFLAGS := -g
• ant debug

I've also ndk-build NDK_DEBUG=1 but I still get where it looks like I don't have debug symbols.

Here's an image of the stack trace. It doesn't get any more informative:

Answer 1

Well NDK_DEBUG=1 and debuggable flag in manifest set to true are required. When you build the app,in your project/libs/armeabi, there should be a gdb.setup file. There is symbol search path there, check whether it is valid. And did you try this:

ndk-gdb --start --verbose --force

And looks like you are getting a null pointer exception.

Answer 2

在最新版本的NDK和Eclipse插件中，您可以右键单击包并选择Debug as - > Android Native Application

Answer 3

Make sure that you load your native library in either a launchable activity or in your Application class. Otherwise it wouldn't work and you'll get the following error No symbol table is loaded. Use the "file" command. No symbol table is loaded. Use the "file" command. .

For example in Application class:

import android.app.Application;

public class MyApp extends Application {

    static {
        System.loadLibrary("Name");
    }

    public static native int doSomething();
}

Name is the name of your library (.so file) without the lib part.

Answer 4

我解决了把--nowait选项放到shell命令：

ndk-gdb --start --verbose --nowait