Gdb 调试 Android 上的本机（不是 jni）程序

Question

我无法使用 NDK 工具链调试本机程序。以下是我的详细步骤和输出。

环境设置：

NDK_ROOT=/opt/android/ndk
SYSROOT=$NDK_ROOT/platforms/android-8/arch-arm
TOOLCHAIN=$NDK_ROOT/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin
PATH=$TOOLCHAIN:$NDK_ROOT:$PATH

来源：hello.c

 1    #include <stdio.h>
 2   
 3    int main() {
 4      printf("Hello World!\n");
 5      return 0;
 6    }

通过 NDK 提供的独立工具链构建。

#arm-linux-androideabi-gcc -g hello.c -o hello --sysroot $SYSROOT 

推送到模拟器并启动 gdbserver（我已经转发了端口）

#adb push hello /data/hello
#adb shell gdbserver 10.0.2.15:10000 /data/hello

在另一个终端中远程调试：

#arm-linux-androideabi-gdb
#(gdb) target remote localhost:10000
Remote debugging using :10000
0xb0001000 in ?? ()       ------------------------------------what is this?
#(gdb) symbol-file hello
Reading symbols from hello...done.
#(gdb) l
1    #include <stdio.h>
2   
3    int main() {
4      printf("Hello World!\n");
5      return 0;
6    }
#(gdb)  b main
Breakpoint 1 at 0x8318: file hello.c, line 4.
#(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.  -------It should be break at main function, but segmentation falut.  

0xafd0f5f0 in ?? ()
#(gdb) bt
#0  0xafd0f5f0 in ?? ()

---

我使用 NDK Android.mk 风格对其进行测试，效果很好。这是输出

Android.mk

1. LOCAL_PATH := $(call my-dir)
2.
3. include $(CLEAR_VARS)
4.
5. LOCAL_MODULE    := hello
6. LOCAL_SRC_FILES := hello.c
7. LOCAL_MODULE_TAGS := optional
8.
9. include $(BUILD_EXECUTABLE)

构建，推送到模拟器，启动调试服务器

   #ndk-build
   #push obj/local/armeabi/hello /data/hello
   #adb shell gdbserver 10.0.2.15:10000 /data/hello

调试远程：

#arm-linux-androideabi-gdb
(gdb) target remote :10000
Remote debugging using :10000
0xb0001000 in ?? ()  --------------still here
(gdb) symbol-file hello
Reading symbols from hello...done.
(gdb) l
1    #include <stdio.h>
2   
3    int main() {
4      printf("Hello World!\n");
5      return 0;
6    }
(gdb) b main
Breakpoint 1 at 0x8372: file hello.c, line 4.
(gdb) c
Continuing.

Breakpoint 1, main () at hello.c:4
4      printf("Hello World!\n");
(gdb) c
Continuing.

Program exited normally.      -------Yes, erverything is normal, Hello World is output.

---

仍然通过 ndk-build 使用 Android.mk 构建，当我在 gdb 远程中执行其他操作时，仍然失败。

(gdb) target remote :10000
Remote debugging using :10000
0xb0001000 in ?? ()
(gdb) symbol-file hello
Reading symbols from hello...done.
(gdb) l
1    #include <stdio.h>
2   
3    int main() {
4      printf("Hello World!\n");
5      return 0;
6    }
(gdb) b main
Breakpoint 1 at 0x8372: file hello.c, line 4.
(gdb) next
Cannot access memory at address 0x0
Cannot find bounds of current function
(gdb) c
Continuing.

Breakpoint 1, main () at hello.c:4
4      printf("Hello World!\n");
(gdb) next
6    }
(gdb) next

Program received signal SIGSEGV, Segmentation fault. ------Again fault. And no "Hello World" output in gdbserver.
0x0000832c in ?? ()
(gdb) next
Cannot find bounds of current function

=================================================== =============

我对android很陌生，任何人都可以告诉我发生了什么？

Answer 1

我不知道为什么 gdb 通过 ndk-build 处理二进制文件，但是使用 file 命令而不是符号文件命令，它可能会工作。 gdb 需要知道远程执行程序的映像。

(gdb) file hello