talkd.c revision 262435 
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. 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#ifndef lint
31static const char copyright[] =
32"@(#) Copyright (c) 1983, 1993\n\
33	The Regents of the University of California.  All rights reserved.\n";
34#endif /* not lint */
35
36#ifndef lint
37#if 0
38static char sccsid[] = "@(#)talkd.c	8.1 (Berkeley) 6/4/93";
39#endif
40static const char rcsid[] =
41  "$FreeBSD: stable/10/libexec/talkd/talkd.c 262435 2014-02-24 08:21:49Z brueffer $";
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 <sys/param.h>
53#include <netinet/in.h>
54#include <protocols/talkd.h>
55#include <err.h>
56#include <errno.h>
57#include <paths.h>
58#include <signal.h>
59#include <stdio.h>
60#include <stdlib.h>
61#include <string.h>
62#include <syslog.h>
63#include <time.h>
64#include <unistd.h>
65
66#include "extern.h"
67
68static CTL_MSG		request;
69static CTL_RESPONSE	response;
70
71int			debug = 0;
72static long		lastmsgtime;
73
74char			hostname[MAXHOSTNAMELEN];
75
76#define TIMEOUT 30
77#define MAXIDLE 120
78
79int
80main(int argc, char *argv[])
81{
82	register CTL_MSG *mp = &request;
83	int cc;
84	struct sockaddr ctl_addr;
85
86#ifdef NOTDEF
87	/*
88	 * removed so ntalkd can run in tty sandbox
89	 */
90	if (getuid())
91		errx(1, "getuid: not super-user");
92#endif
93	openlog("talkd", LOG_PID, LOG_DAEMON);
94	if (gethostname(hostname, sizeof(hostname) - 1) < 0) {
95		syslog(LOG_ERR, "gethostname: %m");
96		_exit(1);
97	}
98	hostname[sizeof(hostname) - 1] = '\0';
99	if (chdir(_PATH_DEV) < 0) {
100		syslog(LOG_ERR, "chdir: %s: %m", _PATH_DEV);
101		_exit(1);
102	}
103	if (argc > 1 && strcmp(argv[1], "-d") == 0)
104		debug = 1;
105	signal(SIGALRM, timeout);
106	alarm(TIMEOUT);
107	for (;;) {
108		cc = recv(0, (char *)mp, sizeof(*mp), 0);
109		if (cc != sizeof (*mp)) {
110			if (cc < 0 && errno != EINTR)
111				syslog(LOG_WARNING, "recv: %m");
112			continue;
113		}
114		lastmsgtime = time(0);
115		(void)memcpy(&ctl_addr, &mp->ctl_addr, sizeof(ctl_addr));
116		ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
117		ctl_addr.sa_len = sizeof(ctl_addr);
118		process_request(mp, &response);
119		/* can block here, is this what I want? */
120		cc = sendto(STDIN_FILENO, (char *)&response,
121		    sizeof(response), 0, &ctl_addr, sizeof(ctl_addr));
122		if (cc != sizeof (response))
123			syslog(LOG_WARNING, "sendto: %m");
124	}
125}
126
127void
128timeout(int sig __unused)
129{
130	int save_errno = errno;
131
132	if (time(0) - lastmsgtime >= MAXIDLE)
133		_exit(0);
134	alarm(TIMEOUT);
135	errno = save_errno;
136}
137