#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main(int argc, char *argv[])
{
	FILE *fp;
	uid_t uid;

	if (argc > 1) {
		uid = atoi(argv[1]);
		if (setuid(uid) < 0) {
			perror("setuid");
			return 1;
		}
	}

	printf("PID=%d UID=%d GID=%d\n", getpid(), geteuid(), getegid());

	if ((fp = fopen("/proc/net/if_inet6", "r")) != 0) {
		printf("PASS: /proc/net/if_inet6 opened\n");
		fclose(fp);
	} else {
		printf("FAIL: Can't open /proc/net/if_inet6\n");
		return 1;
	}
	return 0;
}