gcc4.4下实现backtrace代码

 最近在一块新的板子下作开发， 有些变量发生异常（就是我们不想到的值），可以加上backtrace，知道是哪个函数调用它，导致出现异常， 就像死机了，你可以gdb和core文件用bt 命令，查看死机在哪里（有一种 情况 不能看见， 就是发生信号异常不在本文范围 ）， 本人感觉还有用， 关说不炼、假把式，下面是实现代码：

首先实现核心代码backtrace函数：

 

[html] view plaincopyprint
  1. extern void * __libc_stack_end;
  3. # define BOUNDED_N(PTR, N) (PTR)
  4. #define BOUNDED_1(PTR) BOUNDED_N (PTR, 1)
  5. /* Get some notion of the current stack. Need not be exactly the top
  6. of the stack, just something somewhere in the current frame. */
  7. #ifndef CURRENT_STACK_FRAME
  8. # define CURRENT_STACK_FRAME ({ char __csf; &__csf; })
  9. #endif
  11. /* By default we assume that the stack grows downward. */
  12. #ifndef INNER_THAN
  13. # define INNER_THAN <
  14. #endif
  16. /* By default assume the `next' pointer in struct layout points to the
  17. next struct layout. */
  18. #ifndef ADVANCE_STACK_FRAME
  19. # define ADVANCE_STACK_FRAME(next) BOUNDED_1 ((struct layout *) (((int)next) - 4))
  20. #endif
  22. /* By default, the frame pointer is just what we get from gcc. */
  23. #ifndef FIRST_FRAME_POINTER
  24. # define FIRST_FRAME_POINTER (__builtin_frame_address (0) - 4)
  25. #endif
  27. int backtrace (void **array, int size)
  28. {
  29. struct layout *current;
  30. void *top_frame;
  31. void *top_stack;
  32. int cnt = 0;
  34. top_frame = FIRST_FRAME_POINTER;
  35. top_stack = CURRENT_STACK_FRAME;
  37. /* We skip the call to this function, it makes no sense to record it. */
  38. current = BOUNDED_1 ((struct layout *) top_frame);
  39. while (cnt <size)
  40. {
  41. if ((void *) current->fp INNER_THAN top_stack
  42. || !((void *) current->fp INNER_THAN __libc_stack_end))
  43. {
  44. /* This means the address is out of range. Note that for the
  45. toplevel we see a frame pointer with value NULL which clearly is
  46. out of range. */
  47. break;
  48. }
  50. array[cnt] = current->lr;
  51. cnt++;
  53. current = ADVANCE_STACK_FRAME (current->fp);
  54. }
  55. /*
  56. * In leaf function
  57. * gcc not push lr when call it
  58. */
  59. printf(" ");
  60. return cnt;
  61. } 
extern void * __libc_stack_end;

# define BOUNDED_N(PTR, N) (PTR)
#define BOUNDED_1(PTR) BOUNDED_N (PTR, 1)
/* Get some notion of the current stack.  Need not be exactly the top
   of the stack, just something somewhere in the current frame.  */
#ifndef CURRENT_STACK_FRAME
# define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
#endif

/* By default we assume that the stack grows downward.  */
#ifndef INNER_THAN
# define INNER_THAN <
#endif

/* By default assume the `next' pointer in struct layout points to the
   next struct layout.  */
#ifndef ADVANCE_STACK_FRAME
# define ADVANCE_STACK_FRAME(next) BOUNDED_1 ((struct layout *) (((int)next) - 4))
#endif

/* By default, the frame pointer is just what we get from gcc.  */
#ifndef FIRST_FRAME_POINTER
# define FIRST_FRAME_POINTER  (__builtin_frame_address (0) - 4)
#endif

int backtrace (void **array, int size)
{
    struct layout *current;
    void *top_frame;
    void *top_stack;
    int cnt = 0;

    top_frame = FIRST_FRAME_POINTER;
    top_stack = CURRENT_STACK_FRAME;

    /* We skip the call to this function, it makes no sense to record it.  */
    current = BOUNDED_1 ((struct layout *) top_frame);
    while (cnt < size)
    {
        if ((void *) current->fp INNER_THAN top_stack
                || !((void *) current->fp INNER_THAN __libc_stack_end))
        {
            /* This means the address is out of range.  Note that for the
               toplevel we see a frame pointer with value NULL which clearly is
               out of range.  */
            break;
        }

        array[cnt] = current->lr;
        cnt++;

        current = ADVANCE_STACK_FRAME (current->fp);
    }
    /*
     * In leaf function
     * gcc not push lr when call it
     */
    printf(" ");
    return cnt;
}


下面就是将她加入一个文件中了

 

 

[cpp] view plaincopyprint?
  1. /**
  2. * @fn writeToFile
  3. * @brief backtrace写入文件
  4. * @param[in] *pIndex: 目录
  5. * *pAppend: 附加信息
  6. * @param[out]
  7. * @return BSTAR_OK BSTAR_FAIL
  8. */
  9. int writeToFile(constchar *pIndex, constchar* pAppend)
  10. {
  11. int j, nptrs = 0;
  12. void *buffer[100];
  13. char str[1024] = {0};
  14. int fd = 0;
  16. if(NULL == pIndex)
  17. {
  18. fprintf(stderr, "the Index is NULL!\n");
  19. return -1;
  20. }
  22. if((fd = open(pIndex, O_RDWR|O_APPEND, 0644)) < 0)
  23. {
  24. fd = open(pIndex, O_RDWR|O_CREAT|O_APPEND, 0644);
  25. }
  27. nptrs = backtrace(buffer, 100);
  29. if(NULL != pAppend)
  30. {
  31. write(fd, pAppend, strlen(pAppend));
  32. memset(str, 0, 1024);
  33. }
  35. for (j = 0; j < nptrs; j++)
  36. {
  37. sprintf(str, "%p\n", buffer[j]);
  38. write(fd, str, strlen(str));
  39. memset(str, 0, 1024);
  40. }
  42. write(fd, "================\n", strlen("================\n"));
  43. close(fd);
  45. return 0;
  46. } 
/**
 * @fn          writeToFile
 * @brief       backtrace写入文件
 * @param[in]   *pIndex: 目录
 *              *pAppend: 附加信息
 * @param[out]
 * @return      BSTAR_OK    BSTAR_FAIL
 */
int writeToFile(const char *pIndex, const char* pAppend)
{
    int j, nptrs = 0;
    void *buffer[100];
    char str[1024] = {0};
    int fd = 0;

    if(NULL == pIndex)
    {
       fprintf(stderr, "the Index is NULL!\n");
       return -1;
    }

    if((fd = open(pIndex, O_RDWR|O_APPEND, 0644)) < 0)
    {
        fd = open(pIndex, O_RDWR|O_CREAT|O_APPEND, 0644);
    }

    nptrs = backtrace(buffer, 100);

    if(NULL != pAppend)
    {
        write(fd, pAppend, strlen(pAppend));
        memset(str, 0, 1024);
    }

    for (j = 0; j < nptrs; j++)
    {
        sprintf(str, "%p\n", buffer[j]);
        write(fd, str, strlen(str));
        memset(str, 0, 1024);
    }

    write(fd, "================\n", strlen("================\n"));
    close(fd);

    return 0;
}


好了，就是这些了， 你可以将她编写成so库， 那样就方便调用了

posted @ 2012-11-07 10:26  zhangyoushugz  阅读(544)  评论(0)  编辑  收藏  举报