users.c revision 24360 
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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35static char copyright[] =
36"@(#) Copyright (c) 1980, 1987, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41static char sccsid[] = "@(#)users.c	8.1 (Berkeley) 6/6/93";
42#endif /* not lint */
43
44#include <sys/types.h>
45#include <utmp.h>
46#include <stdio.h>
47
48#define	MAXUSERS	200
49
50main(argc, argv)
51	int argc;
52	char **argv;
53{
54	extern int optind;
55	register int cnt, ncnt;
56	struct utmp utmp;
57	char names[MAXUSERS][UT_NAMESIZE];
58	int ch, scmp();
59
60	while ((ch = getopt(argc, argv, "")) != -1)
61		switch(ch) {
62		case '?':
63		default:
64			(void)fprintf(stderr, "usage: users\n");
65			exit(1);
66		}
67	argc -= optind;
68	argv += optind;
69
70	if (!freopen(_PATH_UTMP, "r", stdin)) {
71		(void)fprintf(stderr, "users: can't open %s.\n", _PATH_UTMP);
72		exit(1);
73	}
74	for (ncnt = 0;
75	    fread((char *)&utmp, sizeof(utmp), 1, stdin) == 1;)
76		if (*utmp.ut_name) {
77			if (ncnt == MAXUSERS) {
78				(void)fprintf(stderr,
79				    "users: too many users.\n");
80				break;
81			}
82			(void)strncpy(names[ncnt], utmp.ut_name, UT_NAMESIZE);
83			++ncnt;
84		}
85
86	if (ncnt) {
87		qsort(names, ncnt, UT_NAMESIZE, scmp);
88		(void)printf("%.*s", UT_NAMESIZE, names[0]);
89		for (cnt = 1; cnt < ncnt; ++cnt)
90			if (strncmp(names[cnt], names[cnt - 1], UT_NAMESIZE))
91				(void)printf(" %.*s", UT_NAMESIZE, names[cnt]);
92		(void)printf("\n");
93	}
94	exit(0);
95}
96
97scmp(p, q)
98	char *p, *q;
99{
100	return(strncmp(p, q, UT_NAMESIZE));
101}
102