文件上锁的部分实现-失败信号的处理

//锁对象的构建

struct flock* file_lock(short type, short whence)
{
 static struct flock ret;
 ret.l_type = type ;
 ret.l_start = 0;
 ret.l_whence = whence;
 ret.l_len = 0;
 ret.l_pid = getpid();
 return &ret;
}

//锁函数的建立

void saveBackTrace(int signal)
{
#ifndef WIN32
 time_t tSetTime;
 time( &tSetTime);
 tm* ptm = localtime(&tSetTime) ;
 char fname[256] = {0};
 sprintf(fname, "core.%d_%d_%d_%d_%d_%d",
  ptm->tm_year + 1900, ptm->tm_mon + 1, ptm->tm_mday,
  ptm->tm_hour, ptm->tm_min, ptm->tm_sec);

//文件的开启

 FILE* f = fopen(fname, "a");
 if (f == NULL)
 {
  return;
 }
 int fd = fileno(f);

//设置文件锁
 fcntl(fd, F_SETLKW, file_lock(F_WRLCK, SEEK_SET));

 char buffer[4096] = {0};
 sprintf(buffer, "Dump Time: %d-%d-%d %d:%d:%d\n",
  ptm->tm_year + 1900, ptm->tm_mon + 1, ptm->tm_mday,
  ptm->tm_hour, ptm->tm_min, ptm->tm_sec);

//内容的输出
 fwrite(buffer, 1, strlen(buffer), f);

 strcpy(buffer, "Catch signal: ");

//信号的判断
 switch (signal)
 {
 case SIGSEGV: strcat(buffer, "SIGSEGV\n");
  break;
 case SIGILL: strcat(buffer, "SIGILL\n");
  break;
 case SIGFPE: strcat(buffer, "SIGFPE\n");
  break;
 case SIGABRT: strcat(buffer, "SIGABRT\n");
  break;
 case SIGTERM: strcat(buffer, "SIGTERM\n");
  break;
 case SIGKILL: strcat(buffer, "SIGKILL\n");
  break;
 case SIGXFSZ: strcat(buffer, "SIGXFSZ\n");
  break;
 default: sprintf(buffer, "Catch signal: %d\n", signal);
  break;
 }

//内容的输出
 fwrite(buffer, 1, strlen(buffer), f);

 sprintf(buffer, "Processing cmd: %d\n", g_processingCmd);
 fwrite(buffer, 1, strlen(buffer), f);

 struct sysinfo s_info;
 int error;

//系统信息的记录
 error = sysinfo(&s_info);
 sprintf(buffer, "code error=[%d]\nUptime =[%ld]s\nLoad: 1 min[%lu] / 5 min[%lu] / 15 min[%lu]"\
  "\nRAM: total[%lu] / free[%lu] / shared[%lu]\n Memory in buffers =[%lu]\nSwap:total[%lu]/free[%lu]"\
  "\nNumber of processes =[%d]\n\n",
  error, s_info.uptime, s_info.loads[0], s_info.loads[1], s_info.loads[2],
  s_info.totalram, s_info.freeram, s_info.sharedram, s_info.bufferram,
  s_info.totalswap, s_info.freeswap, s_info.procs);

 void* DumpArray[256];

//失败的时候，打印堆栈的信息
 int nSize = backtrace(DumpArray, 256);
 char** symbols = backtrace_symbols(DumpArray, nSize);
 if (symbols)
 {
  if (nSize > 256)
  {
   nSize = 256;
  }
  if (nSize > 0)
  {
   for (int i = 0; i < nSize; i++)
   {
    fwrite(symbols[i], 1, strlen(symbols[i]), f);
    fwrite("\n", 1, 1, f);
   }
  }

//释放
  free(symbols);
 }

 

//文件的解锁
 fcntl(fd, F_SETLK, file_lock(F_UNLCK, SEEK_SET));
 fclose(f);

 exit(1);
#endif
}

 

//使用

    signal(SIGSEGV, saveBackTrace);
    signal(SIGILL, saveBackTrace);
    signal(SIGFPE, saveBackTrace);
    signal(SIGABRT, saveBackTrace);
    signal(SIGTERM, saveBackTrace);
    signal(SIGKILL, saveBackTrace);
    signal(SIGXFSZ, saveBackTrace);