在c語言中調用shell指令碼方法

static int
SearchUsingRouteCmd (char *address, struct in_addr *in,struct in_addr *addr_out, char *best_if, size_t best_iflen,unsigned long *best_netmask)
{
 char mask[20];
 char routecmd[MAXSTR];
 int best_metric = INT_MAX;
 char buf[2048];
 char interface[MAXSTR];
 char  *cp, *sp;
 int done = 0;
 FILE *routefd = NULL;
 uint32_t maskbits;

 /* Open route and get the information */
 /*將命令儲存在routecmd變數中*/
 snprintf (routecmd, sizeof(routecmd), "%s %s %s",ROUTE, ROUTEPARM, address);
 /*執行命令列，並獲得檔案描述符*/
 routefd = popen (routecmd, "r");
 if (routefd == NULL)
  return (OCF_ERR_GENERIC);
 mask[0] = EOS;
 interface[0] = EOS;
 /*操作檔案描述符，並擷取命令列執行後列印的訊息*/
 while ((done < 3) && fgets(buf, sizeof(buf), routefd)) {
  int buflen = strnlen(buf, sizeof(buf));
  cp = buf;
  sp = buf + buflen;
  while (sp!=buf && isspace((int)*(sp-1))) {
   --sp;
  }
  *sp = EOS;
  buf[buflen] = EOS;
  if (strstr (buf, "mask:")) {
   /*strsep(&cp, ":");cp++;*/
   cp = strtok(buf, ":");
   cp = strtok(NULL, ":");cp++;
   strncpy(mask,cp,sizeof(mask));
                   done++;
  }
  if (strstr (buf, "interface:")) {
   /*strsep(&cp, ":");cp++;*/
   cp = strtok(buf, ":");
   cp = strtok(NULL, ":");cp++;
   strncpy(interface, cp, sizeof(interface));
                   done++;
  }
 }
 fclose(routefd);
}