/*
 * Here we play with the UID related system calls
 */
#define _GNU_SOURCE
#include <sys/param.h>
#include <sys/types.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

/* Prototypes */
static void display_uids(void);

int
main(void)
{
	uid_t	r, e, s;

	/* Display uids */
	display_uids();

	/* Pause */
	(void) fprintf(stdout, "Hit return to continue");
	(void) fgetc(stdin);

	return (0);
}

/* Display current real, effective and saved uids */
static void
display_uids(void)
{
	uid_t	ruid, euid, suid;

	/* Retrieve real, effective and saved uids */
	if (getresuid(&ruid, &euid, &suid) < 0) {
		perror("getresuid()");
		exit(EXIT_FAILURE);
	}

	(void) fprintf(stdout, "Real uid:\t%d\n", (int)ruid);
	(void) fprintf(stdout, "Effective uid:\t%d\n", (int)euid);
	(void) fprintf(stdout, "Saved uid:\t%d\n", (int)suid);
}