xref: /src/usr.bin/users/users.c

/*	$NetBSD: users.c,v 1.17 2016/09/05 00:40:30 sevan Exp $	*/

/*
 * Copyright (c) 1980, 1987, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)users.c	8.1 (Berkeley) 6/6/93";
#endif
__RCSID("$NetBSD: users.c,v 1.17 2016/09/05 00:40:30 sevan Exp $");
#endif /* not lint */

#include <sys/types.h>

#include <err.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "utmpentry.h"

int
main(int argc, char **argv)
{
	int ncnt = 0;
	int ch;
	struct utmpentry *from, *ehead, *save, **nextp;

	while ((ch = getopt(argc, argv, "")) != -1)
		switch(ch) {
		case '?':
		default:
			(void)fprintf(stderr, "usage: %s\n", getprogname());
			exit(1);
		}
	argc -= optind;
	argv += optind;

	ncnt = getutentries(NULL, &ehead);

	if (ncnt == 0)
		return 0;

	/*
	 * XXX the utmp list belongs to getutentries and we shouldn't
	 * sort it in place. Since we don't call endutentries and we
	 * don't call getutentries again it doesn't matter, but it's
	 * untidy. Maybe give getutentries a sort function? It has to
	 * sort anyway if it's merging utmp and utmpx data.
	 */

	from = ehead;
	ehead = NULL;
	while (from != NULL) {
		for (nextp = &ehead;
		    (*nextp) && strcmp(from->name, (*nextp)->name) > 0;
		    nextp = &(*nextp)->next)
			continue;
		save = from;
		from = from->next;
		save->next = *nextp;
		*nextp = save;
	}

	save = ehead;
	(void)printf("%s", ehead->name);

	for (from = ehead->next; from; from = from->next)
		if (strcmp(save->name, from->name) != 0) {
			(void)printf(" %s", from->name);
			save = from;
		}

	(void)printf("\n");
	exit(0);
}