巧用backtrace系列函数，在不具备gdb环境的Linux系统上大致定位段错误位置

1: 段错误产生的原因

2: SIGSEGV信号处理函数

signal(SIGSEGV, &your_function);

3: libc的Backtraces函数

01.A backtrace is a list of the function calls that are currently active in a  
02.thread. The usual way to inspect a backtrace of a program is to use an  
03.external debugger such as gdb. However, sometimes it is useful to  
04.obtain a backtrace programmatically from within a program, e.g., for the  
05.purposes of logging or diagnostics.  
06.   
07.The header file execinfo.h declares three functions that obtain and  
08.manipulate backtraces of the current thread.

4: 实现步骤

#include <execinfo.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
 
void dump(int signo)
{
    void *array[30];
    size_t size;
    char **strings;
    size_t i;
 
    size = backtrace (array, 30);
    strings = backtrace_symbols (array, size);
 
    fprintf (stderr,"Obtained %zd stack frames.nm", size);
 
    for (i = 0; i < size; i++)
        fprintf (stderr,"%sn", strings[i]);
 
    free (strings);
 
    exit(0);
}
 
Debug_Printf_FrameInfos()
{
    signal(SIGSEGV, &dump);
}

5 定位出错函数地址实例

#include <execinfo.h> 
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
 
void dump(int signo)
{
    void *array[30];
    size_t size;
    char **strings;
    size_t i;
 
    size = backtrace (array, 30);
    strings = backtrace_symbols (array, size);
 
    fprintf (stderr,"Obtained %zd stack frames.nm", size);
 
    for (i = 0; i <= size; i++)
        fprintf (stderr,"%s\n", strings[i]);
 
    free (strings);
    exit(0);
}
 
Debug_Printf_FrameInfos()
{
    signal(SIGSEGV, dump);
}
 
void func_c()
{
    * ((volatile char *) 0x0) = 0x999;
}
void func_b()
{
    func_c();
}
void func_a()
{
    func_b();
}
int main()
{
    Debug_Printf_FrameInfos();
    func_a();
    return 0;
}

5.1编译程序:

5.2 运行 test程序:

#  ./test
Obtained 7 stack frames.nm./a.out [0x80484e3]
[0xb7f70420]
./a.out [0x804859d]
./a.out [0x80485a7]
./a.out [0x80485c4]
/lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe0) [0xb7e1e450]
./a.out [0x8048461]
Segmentation fault

# ./test 
Obtained 7 stack frames.nm./test(dump+0x1f) [0x80487c3]
[0xb7fbb420]
./test(func_b+0x8) [0x804887d]
./test(func_a+0x8) [0x8048887]
./test(main+0x1b) [0x80488a4]
/lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe0) [0xb7e69450]
./test [0x8048741]

5.3 使用objdump获取程序所有符合

5.4 分析和查找