xref: /freebsd/usr.bin/users/users.cc (revision 031beb4e239bfce798af17f5fe8dba8bcaf13d99)
1 /*-
2  * Copyright (c) 2014 Pietro Cerutti <gahr@FreeBSD.org>
3  * 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. 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 #include <sys/cdefs.h>
31 #include <sys/capsicum.h>
32 
33 #include <capsicum_helpers.h>
34 #include <err.h>
35 #include <errno.h>
36 #include <utmpx.h>
37 
38 #include <algorithm>
39 #include <iostream>
40 #include <iterator>
41 #include <set>
42 #include <string>
43 using namespace std;
44 
45 int
46 main(int argc, char **)
47 {
48 	struct utmpx *ut;
49 	set<string> names;
50 
51 	if (argc > 1) {
52 		cerr << "usage: users" << endl;
53 		return (1);
54 	}
55 
56 	setutxent();
57 
58 	if (caph_enter())
59 		err(1, "Failed to enter capability mode.");
60 
61 	while ((ut = getutxent()) != NULL)
62 		if (ut->ut_type == USER_PROCESS)
63 			names.insert(ut->ut_user);
64 	endutxent();
65 
66 	if (!names.empty()) {
67 		set<string>::iterator last = names.end();
68 		--last;
69 		copy(names.begin(), last, ostream_iterator<string>(cout, " "));
70 		cout << *last << endl;
71 	}
72 }
73