輔助函式 crash log

今天來分享C++ 怎麼做程式crash的stack trace

捕捉 crash

這次只介紹linux系列的crash log，之後再補windows的，兩邊做法不太一樣；另外在crash示範的部分，先用空指針這種錯誤來示範

#include <stdio.h>
#include <signal.h>
#include <time.h>
#include <fstream>
#include <execinfo.h>
#include <string.h>
#include <time.h>

const int MAX_STACK_FRAMES = 128;

void GetTimeString(char *psz)
{
    if (NULL == psz)
    {
        return;
    }

    time_t t = time(NULL);
    tm *now = localtime(&t);
    sprintf(psz, "%04d-%02d-%02d %02d:%02d:%02d", now->tm_year + 1900, now->tm_mon + 1, now->tm_mday, now->tm_hour, now->tm_min, now->tm_sec);
}

void sig_crash(int sig)
{
    FILE *fd = fopen("crashlog.log", "a");    

    if (NULL == fd)
    {
        exit(0);
    }
    try
    {
        char szLine[512] = {
            0,
        };
        time_t t = time(NULL);
        tm *now = localtime(&t);
        int nLen1 = sprintf(szLine,
                            "#########################################################\n[%04d-%02d-%02d %02d:%02d:%02d][crash signal number:%d]\n",
                            now->tm_year + 1900,
                            now->tm_mon + 1,
                            now->tm_mday,
                            now->tm_hour,
                            now->tm_min,
                            now->tm_sec,
                            sig);
        fwrite(szLine, strlen(szLine), 1, fd);

        char szTmp[4096];
        char szTime[256];
        GetTimeString(szTime);
#ifdef __linux
        void* pStacks[MAX_STACK_FRAMES];
  size_t nStackDepth;      
  char **SymbolAry;

  nStackDepth = (int)backtrace(pStacks, MAX_STACK_FRAMES);

  SymbolAry = backtrace_symbols(pStacks, nStackDepth);
  if (SymbolAry == NULL)
  {
   snprintf(szTmp, sizeof(szTmp), "no backtrace_symbols\n", szTime);
   fwrite(szTmp, strlen(szTmp), 1, fd);
  }
  else
  {
   for (int j = 0; j < nStackDepth; j++)
   {
    if (SymbolAry[j])
    {
     snprintf(szTmp, sizeof(szTmp), "%s\n", SymbolAry[j]);
     fwrite(szTmp, strlen(szTmp), 1, fd);
    }
   }

   free(SymbolAry);
     }
#endif // __linux
    }
    catch (...)
    {
        //
    }
    fflush(fd);
    fclose(fd);
    fd = NULL;
    exit(0);
}

int main()
{
    // 紀錄要偵測的錯誤信號及回調函式
    signal(SIGSEGV, sig_crash);
    signal(SIGABRT, sig_crash);

    int *a = NULL;
    a[10] = 0; // crash
    
    return 0;
}

參考

C++ 捕捉 crash 信号（win&Linux