#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <pwd.h>

int main(void) {

	struct passwd *pw;
    pw = getpwnam("nobody");
	if (pw == NULL) {
		fprintf(stderr, "User nobody does not exists.\n");
		exit(-1);
	}
	if ((chdir("/var/empty")) == -1) {
		fprintf(stderr, "Directory /var/empty does not exists.\n");
		exit(-1);
	}
	if((chroot("/var/empty")) == -1) {
		fprintf(stderr, "Failed to chroot in /var/empty.\n");
        perror("chroot");
        exit(-1);
	}
	if ((setgid(pw->pw_gid) == -1) || (setuid(pw->pw_uid) == -1) || (setegid(pw->pw_gid) == -1) || (seteuid(pw->pw_uid) == -1)) {
		fprintf(stderr, "Cannot drop privileges.\n");
		exit(-1);
	}
	
	printf("Privileges reduction successful.\n");
	
	return 0;
}