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


main(int argc, char **argv, char **envp)
{
	time_t			timer;
	int				error;
	char			*user;
	struct passwd   *pwd;
	char			s[256];
	int				id;

	extern int errno;

	time(&timer);

	if ( NULL == ( pwd = getpwuid ( id=getuid () )))
	{
		fprintf(stderr, "getpw failed (%s) for %d at %s",
		strerror(errno),
		getuid(),
		ctime(&timer)
		);
		exit(errno);
	}

	user = pwd->pw_name;

	if( (error = setuid((uid_t) 0L)) != 0 )
	{
		fprintf(stderr, "%s: warning: setuid failed for %s (%s) at %s",
		argv[0],
		user,
		strerror(errno),
		ctime(&timer)
		);
	}
	puts("I should be root");
	gets(s);


	if( (error = seteuid((uid_t) id)) != 0 )
	{
		fprintf(stderr, "%s: warning: seteuid failed for %s (%s) at %s",
		argv[0],
		user,
		strerror(errno),
		ctime(&timer)
		);
	}
	puts("I should e-be user");
	gets(s);


	if( (error = seteuid((uid_t) 0L)) != 0 )
	{
		fprintf(stderr, "%s: warning: seteuid failed for %s (%s) at %s",
		argv[0],
		user,
		strerror(errno),
		ctime(&timer)
		);
	}
	puts("I should e-be root");
	gets(s);

	if( (error = setuid((uid_t) id)) != 0 )
	{
		fprintf(stderr, "%s: warning: setuid failed for %s (%s) at %s",
		argv[0],
		user,
		strerror(errno),
		ctime(&timer)
		);
	}
	puts("I should be user");
	gets(s);
}