pref: 预先分配路径字符串数组，避免过长时动态分配失败

main.cc

@@ -15,10 +15,8 @@ int main(int argc, char **argv)
     FILE *fp;
     char errbuf[200];
 
-    char *config_path;
-    config_path = getcwd(NULL, 0);
-    sprintf(config_path, "%s/%s", config_path, config_file_path);
-
+    char config_path[200];
+    sprintf(config_path, "%s/%s", getcwd(NULL, 0), config_file_path);
     log_info("load config from %s", config_path);
     fp = fopen(config_path, "r");
     if (!fp)