#define _GNU_SOURCE

#include <errno.h>

#include <stdlib.h>

#include <unistd.h>

#include <stdio.h>

#include <sched.h>

int main(int argc, char **argv)

{

	if (argc < 2) {

		fprintf(stderr, "Usage: newns PROGRAM [ARGUMENTS ...]\n");

		exit(1);

	}

	/* This is best-effort; if the kernel is too old (Linux << 2.6.16),

	 * or indeed if the kernel isn't Linux so we don't have

	 * unshare(CLONE_NEWNS), don't worry about it.

	 */

#ifdef __linux__

	if (unshare(CLONE_NEWNS) < 0 && errno != ENOSYS)

		perror("unshare failed");

		/* ... but continue anyway */

#endif /* __linux__ */

	setenv("OS_PROBER_NEWNS", "1", 1);

	execvp(argv[1], argv + 1);

	perror("execvp failed");

	_exit(127);

}