Android下用gdb进行系统级源码调试

原文地址：http://blog.csdn.net/ariesjzj/article/details/7375048

Host: Ubuntu

Target: Android ICS

1. 将gdbserver和gdb分别放入target和host。两者都可在android源代码的prebuilt目录下找到。

2. 在Target上启动gdbserver，在adb shell中执行

$ /path/to/gdbserver :1111 --attach PID

其中PID为想要debug程序的进程号，可以通过ps得到。1111为端口号，可以自定义。

3. 在Host上启动gdbclient，首先将target上的库pull到host上（如/home/jzj/debug/gdb）

$cd /home/jzj/debug/gdb
$adb pull /system/lib
$adb pull /system/bin/app_process

然后写启动脚本init.gdb（这里假设程序要用到的库放在/home/jzj/debug/gdb/下，Android的symbol放在/home/jzj/debug/ics/symbols/system/lib/下，android的源码放在/home/jzj/workspace/ics下）

file /home/jzj/debug/gdb/app_process
set solib-absolute-prefix /home/jzj/debug/ics/symbols/
set solib-search-path /home/jzj/debug/ics/symbols/system/lib/:/home/jzj/debug/gdb
dir /home/jzj/workspace/ics
shell adb forward tcp:1111 tcp:1111
target remote :1111其中的路径要是懒得自己打有个方法可以自动生成，执行. build/envsetup.sh后，会有gdbclient命令，执行后会生成gdbclient.cmds，把其中的路径拷过来就行。

最后执行

$ gdb -x init.gdb

就可以启动gdb了。一切正常的话这时候就可以用gdb的基本功能，如设断点或者查看内存了。这时如果有些so库的符号表还没载入，可以执行

(gdb) shared

载入这些符号表。

 

最后附个关于gdb设置脚本中两个变量的官方解释，一般solib-absolute-prefix先于solib-search-path查找。
solib-absolute-prefix ：

If this variable is set, path will be used as a prefix for any absolute shared library paths; many runtime loaders store the absolute paths to the shared library in the target program's memory. If you use `solib-absolute-prefix' to find shared libraries, they
need to be laid out in the same way that they are on the target, with e.g. a `/usr/lib' hierarchy under path. You can set the default value of `solib-absolute-prefix' by using the configure-time `--with-sysroot' option.

solib-search-path ：

If this variable is set, path is a colon-separated list of directories to search for shared libraries. `solib-search-path' is used after `solib-absolute-prefix' fails to locate the library, or if the path to the library is relative instead of absolute. If you
want to use `solib-search-path' instead of `solib-absolute-prefix', be sure to set `solib-absolute-prefix' to a nonexistant directory to prevent GDB from finding your host's libraries.