xref: /freebsd/libexec/talkd/talkd.c (revision 4f52dfbb8d6c4d446500c5b097e3806ec219fbd4)
1 /*
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
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.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #ifndef lint
33 static const char copyright[] =
34 "@(#) Copyright (c) 1983, 1993\n\
35 	The Regents of the University of California.  All rights reserved.\n";
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)talkd.c	8.1 (Berkeley) 6/4/93";
41 #endif
42 static const char rcsid[] =
43   "$FreeBSD$";
44 #endif /* not lint */
45 
46 /*
47  * The top level of the daemon, the format is heavily borrowed
48  * from rwhod.c. Basically: find out who and where you are;
49  * disconnect all descriptors and ttys, and then endless
50  * loop on waiting for and processing requests
51  */
52 #include <sys/types.h>
53 #include <sys/socket.h>
54 #include <sys/param.h>
55 #include <netinet/in.h>
56 #include <protocols/talkd.h>
57 #include <err.h>
58 #include <errno.h>
59 #include <paths.h>
60 #include <signal.h>
61 #include <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64 #include <syslog.h>
65 #include <time.h>
66 #include <unistd.h>
67 
68 #include "extern.h"
69 
70 static CTL_MSG		request;
71 static CTL_RESPONSE	response;
72 
73 int			debug = 0;
74 static long		lastmsgtime;
75 
76 char			hostname[MAXHOSTNAMELEN];
77 
78 #define TIMEOUT 30
79 #define MAXIDLE 120
80 
81 int
82 main(int argc, char *argv[])
83 {
84 	register CTL_MSG *mp = &request;
85 	int cc;
86 	struct sockaddr ctl_addr;
87 
88 #ifdef NOTDEF
89 	/*
90 	 * removed so ntalkd can run in tty sandbox
91 	 */
92 	if (getuid())
93 		errx(1, "getuid: not super-user");
94 #endif
95 	openlog("talkd", LOG_PID, LOG_DAEMON);
96 	if (gethostname(hostname, sizeof(hostname) - 1) < 0) {
97 		syslog(LOG_ERR, "gethostname: %m");
98 		_exit(1);
99 	}
100 	hostname[sizeof(hostname) - 1] = '\0';
101 	if (chdir(_PATH_DEV) < 0) {
102 		syslog(LOG_ERR, "chdir: %s: %m", _PATH_DEV);
103 		_exit(1);
104 	}
105 	if (argc > 1 && strcmp(argv[1], "-d") == 0)
106 		debug = 1;
107 	signal(SIGALRM, timeout);
108 	alarm(TIMEOUT);
109 	for (;;) {
110 		cc = recv(0, (char *)mp, sizeof(*mp), 0);
111 		if (cc != sizeof (*mp)) {
112 			if (cc < 0 && errno != EINTR)
113 				syslog(LOG_WARNING, "recv: %m");
114 			continue;
115 		}
116 		lastmsgtime = time(0);
117 		(void)memcpy(&ctl_addr, &mp->ctl_addr, sizeof(ctl_addr));
118 		ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
119 		ctl_addr.sa_len = sizeof(ctl_addr);
120 		process_request(mp, &response);
121 		/* can block here, is this what I want? */
122 		cc = sendto(STDIN_FILENO, (char *)&response,
123 		    sizeof(response), 0, &ctl_addr, sizeof(ctl_addr));
124 		if (cc != sizeof (response))
125 			syslog(LOG_WARNING, "sendto: %m");
126 	}
127 }
128 
129 void
130 timeout(int sig __unused)
131 {
132 	int save_errno = errno;
133 
134 	if (time(0) - lastmsgtime >= MAXIDLE)
135 		_exit(0);
136 	alarm(TIMEOUT);
137 	errno = save_errno;
138 }
139