ulog-helper.c revision 200085 
1/*-
2 * Copyright (c) 2009 Ed Schouten <ed@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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/libexec/ulog-helper/ulog-helper.c 200085 2009-12-03 21:44:41Z ed $");
29
30#include <pwd.h>
31#include <unistd.h>
32#include <stdlib.h>
33#include <string.h>
34#include <sysexits.h>
35#include <ulog.h>
36
37/*
38 * This setuid helper utility writes user login records to disk.
39 * Unprivileged processes are not capable of writing records to utmp,
40 * wtmp and lastlog, but we do want to allow this for pseudo-terminals.
41 * Because a file descriptor to a pseudo-terminal master device can only
42 * be obtained by processes using the pseudo-terminal, we expect such a
43 * descriptor on stdin.
44 *
45 * It uses the real user ID of the calling process to determine the
46 * username.  It does allow users to log arbitrary hostnames.
47 */
48
49int
50main(int argc, char *argv[])
51{
52	const char *line;
53
54	/* Device line name. */
55	if ((line = ptsname(STDIN_FILENO)) == NULL)
56		return (EX_USAGE);
57
58	if ((argc == 2 || argc == 3) && strcmp(argv[1], "login") == 0) {
59		struct passwd *pwd;
60		const char *host = NULL;
61
62		/* Username. */
63		pwd = getpwuid(getuid());
64		if (pwd == NULL)
65			return (EX_OSERR);
66
67		/* Hostname. */
68		if (argc == 3)
69			host = argv[2];
70
71		ulog_login(line, pwd->pw_name, host);
72		return (EX_OK);
73	} else if (argc == 2 && strcmp(argv[1], "logout") == 0) {
74		ulog_logout(line);
75		return (EX_OK);
76	}
77
78	return (EX_USAGE);
79}
80