2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2009 Ed Schouten <ed@FreeBSD.org>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
40 * This setuid helper utility writes user login records to disk.
41 * Unprivileged processes are not capable of writing records to utmpx,
42 * but we do want to allow this for pseudo-terminals. Because a file
43 * descriptor to a pseudo-terminal master device can only be obtained by
44 * processes using the pseudo-terminal, we expect such a descriptor on
47 * It uses the real user ID of the calling process to determine the
48 * username. It does allow users to log arbitrary hostnames.
54 const struct passwd *pw;
59 * Attempt to determine the username corresponding to this login
60 * session. First, validate the results of getlogin() against
61 * the password database. If getlogin() returns invalid data,
62 * return an arbitrary username corresponding to this uid.
65 if ((login = getlogin()) != NULL && (pw = getpwnam(login)) != NULL &&
68 if ((pw = getpwuid(uid)) != NULL)
74 main(int argc, char *argv[])
76 const char *line, *user, *host;
78 /* Device line name. */
79 if ((line = ptsname(STDIN_FILENO)) == NULL)
82 if ((argc == 2 || argc == 3) && strcmp(argv[1], "login") == 0) {
84 user = get_username();
89 host = argc == 3 ? argv[2] : NULL;
91 ulog_login(line, user, host);
93 } else if (argc == 2 && strcmp(argv[1], "logout") == 0) {