void check_user_namespace(void) {
	EUID_ASSERT();
	if (getuid() == 0)
		goto errout;

	// test user namespaces available in the kernel
	struct stat s1;
	struct stat s2;
	struct stat s3;
	if (stat("/proc/self/ns/user", &s1) == 0 &&
	    stat("/proc/self/uid_map", &s2) == 0 &&
	    stat("/proc/self/gid_map", &s3) == 0)
		arg_noroot = 1;
	else
		goto errout;

	return;

errout:
	fwarning("noroot option is not available\n");
	arg_noroot = 0;

}
void check_user_namespace(void) {
	EUID_ASSERT();
	if (getuid() == 0)
		goto errout;

	 
	struct stat s1;
	struct stat s2;
	struct stat s3;
	if (stat("/proc/self/ns/user", &s1) == 0 &&
	    stat("/proc/self/uid_map", &s2) == 0 &&
	    stat("/proc/self/gid_map", &s3) == 0)
		arg_noroot = 1;
	else
		goto errout;

	return;

errout:
	fwarning("noroot option is not available\n");
	arg_noroot = 0;

}