talkd.c revision 1593 
1/*
2 * Copyright (c) 1983, 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) 1983, 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[] = "@(#)talkd.c	8.1 (Berkeley) 6/4/93";
42#endif /* not lint */
43
44/*
45 * The top level of the daemon, the format is heavily borrowed
46 * from rwhod.c. Basically: find out who and where you are;
47 * disconnect all descriptors and ttys, and then endless
48 * loop on waiting for and processing requests
49 */
50#include <sys/types.h>
51#include <sys/socket.h>
52#include <protocols/talkd.h>
53#include <signal.h>
54#include <syslog.h>
55#include <time.h>
56#include <errno.h>
57#include <unistd.h>
58#include <stdio.h>
59#include <stdlib.h>
60#include <string.h>
61#include <paths.h>
62
63CTL_MSG		request;
64CTL_RESPONSE	response;
65
66int	sockt;
67int	debug = 0;
68void	timeout();
69long	lastmsgtime;
70
71char	hostname[32];
72
73#define TIMEOUT 30
74#define MAXIDLE 120
75
76main(argc, argv)
77	int argc;
78	char *argv[];
79{
80	register CTL_MSG *mp = &request;
81	int cc;
82
83	if (getuid()) {
84		fprintf(stderr, "%s: getuid: not super-user\n", argv[0]);
85		exit(1);
86	}
87	openlog("talkd", LOG_PID, LOG_DAEMON);
88	if (gethostname(hostname, sizeof (hostname) - 1) < 0) {
89		syslog(LOG_ERR, "gethostname: %m");
90		_exit(1);
91	}
92	if (chdir(_PATH_DEV) < 0) {
93		syslog(LOG_ERR, "chdir: %s: %m", _PATH_DEV);
94		_exit(1);
95	}
96	if (argc > 1 && strcmp(argv[1], "-d") == 0)
97		debug = 1;
98	signal(SIGALRM, timeout);
99	alarm(TIMEOUT);
100	for (;;) {
101		extern int errno;
102
103		cc = recv(0, (char *)mp, sizeof (*mp), 0);
104		if (cc != sizeof (*mp)) {
105			if (cc < 0 && errno != EINTR)
106				syslog(LOG_WARNING, "recv: %m");
107			continue;
108		}
109		lastmsgtime = time(0);
110		process_request(mp, &response);
111		/* can block here, is this what I want? */
112		cc = sendto(sockt, (char *)&response,
113		    sizeof (response), 0, (struct sockaddr *)&mp->ctl_addr,
114		    sizeof (mp->ctl_addr));
115		if (cc != sizeof (response))
116			syslog(LOG_WARNING, "sendto: %m");
117	}
118}
119
120void
121timeout()
122{
123
124	if (time(0) - lastmsgtime >= MAXIDLE)
125		_exit(0);
126	alarm(TIMEOUT);
127}
128