1/*
2 * Copyright (c) 1980, 1987, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#ifndef lint
31static const char copyright[] =
32"@(#) Copyright (c) 1980, 1987, 1993\n\
33	The Regents of the University of California.  All rights reserved.\n";
34#endif /* not lint */
35
36#ifndef lint
37#if 0
38static char sccsid[] = "@(#)users.c	8.1 (Berkeley) 6/6/93";
39#endif
40static const char rcsid[] =
41  "$FreeBSD: releng/10.3/usr.bin/users/users.c 223222 2011-06-18 07:47:15Z ed $";
42#endif /* not lint */
43
44#include <sys/param.h>
45#include <sys/types.h>
46#include <err.h>
47#include <stdio.h>
48#include <stdlib.h>
49#include <string.h>
50#include <unistd.h>
51#include <utmpx.h>
52
53typedef char   namebuf[sizeof(((struct utmpx *)0)->ut_user) + 1];
54
55int scmp(const void *, const void *);
56static void usage(void);
57
58int
59main(int argc, char **argv)
60{
61	namebuf *names = NULL;
62	int ncnt = 0;
63	int nmax = 0;
64	int cnt;
65	struct utmpx *ut;
66	int ch;
67
68	while ((ch = getopt(argc, argv, "")) != -1)
69		switch(ch) {
70		case '?':
71		default:
72			usage();
73		}
74	argc -= optind;
75	argv += optind;
76
77	setutxent();
78	while ((ut = getutxent()) != NULL) {
79		if (ut->ut_type != USER_PROCESS)
80			continue;
81		if (ncnt >= nmax) {
82			nmax += 32;
83			names = realloc(names, sizeof(*names) * nmax);
84			if (!names) {
85				errx(1, "realloc");
86				/* NOTREACHED */
87			}
88		}
89		(void)strlcpy(names[ncnt], ut->ut_user, sizeof(*names));
90		++ncnt;
91	}
92	endutxent();
93	if (ncnt > 0) {
94		qsort(names, ncnt, sizeof(namebuf), scmp);
95		(void)printf("%s", names[0]);
96		for (cnt = 1; cnt < ncnt; ++cnt)
97			if (strcmp(names[cnt], names[cnt - 1]) != 0)
98				(void)printf(" %s", names[cnt]);
99		(void)printf("\n");
100	}
101	exit(0);
102}
103
104static void
105usage(void)
106{
107	(void)fprintf(stderr, "usage: users\n");
108	exit(1);
109}
110
111int
112scmp(const void *p, const void *q)
113{
114
115	return (strcmp(p, q));
116}
117