snprintf(file_name, sizeof(file_name), "/sys/class/tty/%s", dev);
count = readlink(file_name, file_name, sizeof(file_name));
if (count <= 0 || count >= (int) sizeof(file_name)-1)
snprintf(file_name, sizeof(file_name), "/sys/class/tty/%s", dev);
count = readlink(file_name, file_name, sizeof(file_name));
if (count <= 0 || count >= (int) sizeof(file_name)-1)