/* See LICENSE file for copyright and license details. */
#include <sys/mount.h>
#include <sched.h>
#include <libsimple.h>
#include <libsimple-arg.h>

NUSAGE(125, "mountpoint utility [argument] ...");


int
main(int argc, char *argv[])
{
	const char *mountpoint;

	libsimple_default_failure_exit = 125;

	ARGBEGIN {
	default:
		usage();
	} ARGEND;

	if (argc < 2)
		usage();

	mountpoint = *argv++;
	argc--;

	if (unshare(CLONE_NEWNS))
		eprintf("unshare CLONE_NEWNS:");
	if (mount("none", "/", NULL, MS_REC | MS_SLAVE, NULL))
		eprintf("mount none / NULL MS_REC|MS_SLAVE NULL:");

	if (mount("tmpfs", mountpoint, "tmpfs", 0, NULL))
		eprintf("mount tmpfs %s tmpfs 0 NULL:", mountpoint);

	if (setegid(getgid()))
		eprintf("setegid <real group>:");
	if (seteuid(getuid()))
		eprintf("seteuid <real user>:");

	execvp(argv[0], argv);
	enprintf(errno == ENOENT ? 127 : 126, "execvp %s:", argv[0]);
	return 0;
}