#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <linux/openat2.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>

#define RESOLVE_CACHED	0x20

static int io_openat2(const char *path, int dfd)
{
	struct open_how how;
	int ret;

	memset(&how, 0, sizeof(how));
	how.flags = O_RDONLY;
	how.resolve = RESOLVE_CACHED;

	ret = syscall(437, dfd, path, &how, sizeof(how));
	if (ret == -1)
		return -errno;
	return ret;
}

int main(int argc, char *argv[])
{
	mkdir("/proc2", 0644);
	mount("none", "/proc2", "proc", 0, NULL);
	io_openat2("/proc2/self/comm", -1);
	umount("/proc2");
	return 0;
}