xref: /freebsd/libexec/talkd/talkd.c (revision 193d9e768ba63fcfb187cfd17f461f7d41345048)
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
31 static 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
38 static char sccsid[] = "@(#)talkd.c	8.1 (Berkeley) 6/4/93";
39 #endif
40 static const char rcsid[] =
41   "$FreeBSD$";
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 
68 static CTL_MSG		request;
69 static CTL_RESPONSE	response;
70 
71 int			debug = 0;
72 static long		lastmsgtime;
73 
74 char			hostname[MAXHOSTNAMELEN];
75 
76 #define TIMEOUT 30
77 #define MAXIDLE 120
78 
79 int
80 main(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 
127 void
128 timeout(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