1 /*        $NetBSD: talkd.c,v 1.21 2009/03/16 01:04:32 lukem Exp $     */
2 
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 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1983, 1993\
35  The Regents of the University of California.  All rights reserved.");
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)talkd.c     8.1 (Berkeley) 6/4/93";
41 #else
42 __RCSID("$NetBSD: talkd.c,v 1.21 2009/03/16 01:04:32 lukem Exp $");
43 #endif
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 
56 #include <protocols/talkd.h>
57 
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 CTL_MSG             request;
71 CTL_RESPONSE        response;
72 
73 int       sockt = STDIN_FILENO;
74 int       debug = 0;
75 int       logging = 0;
76 time_t    lastmsgtime;
77 
78 char      hostname[MAXHOSTNAMELEN + 1];
79 
80 #define TIMEOUT 30
81 #define MAXIDLE 120
82 
83 static void timeout(int);
84 int       main(int, char *[]);
85 
86 int
main(int argc,char * argv[])87 main(int argc, char *argv[])
88 {
89           CTL_MSG *mp = &request;
90           int cc, ch;
91           struct sockaddr ctl_addr;
92 
93           openlog("talkd", LOG_PID, LOG_DAEMON);
94           while ((ch = getopt(argc, argv, "dl")) != -1)
95                     switch (ch) {
96                     case 'd':
97                               debug = 1;
98                               break;
99                     case 'l':
100                               logging = 1;
101                               break;
102                     default:
103                               syslog(LOG_ERR, "Usage: %s [-dl]", getprogname());
104                               exit(1);
105                     }
106 
107           if (gethostname(hostname, sizeof hostname) < 0) {
108                     syslog(LOG_ERR, "gethostname: %m");
109                     _exit(1);
110           }
111           hostname[MAXHOSTNAMELEN] = '\0';  /* ensure null termination */
112           if (chdir(_PATH_DEV) < 0) {
113                     syslog(LOG_ERR, "chdir: %s: %m", _PATH_DEV);
114                     _exit(1);
115           }
116           signal(SIGALRM, timeout);
117           alarm(TIMEOUT);
118           for (;;) {
119                     memset(&response, 0, sizeof(response));
120                     cc = recv(0, (char *)mp, sizeof (*mp), 0);
121                     if (cc != sizeof (*mp)) {
122                               if (cc < 0 && errno != EINTR)
123                                         syslog(LOG_WARNING, "recv: %m");
124                               continue;
125                     }
126 
127                     mp->l_name[sizeof(mp->l_name) - 1] = '\0';
128                     mp->r_name[sizeof(mp->r_name) - 1] = '\0';
129                     mp->r_tty[sizeof(mp->r_tty) - 1] = '\0';
130 
131                     lastmsgtime = time(0);
132                     process_request(mp, &response);
133 
134                     tsa2sa(&ctl_addr, &mp->ctl_addr);
135                     if (ctl_addr.sa_family != AF_INET)
136                               continue;
137 
138                     /* can block here, is this what I want? */
139                     cc = sendto(sockt, (char *)&response, sizeof (response), 0,
140                         &ctl_addr, sizeof (ctl_addr));
141                     if (cc != sizeof (response))
142                               syslog(LOG_WARNING, "sendto: %m");
143           }
144 }
145 
146 void
timeout(int n)147 timeout(int n)
148 {
149           int save_errno = errno;
150 
151           if (time(0) - lastmsgtime >= MAXIDLE)
152                     _exit(0);
153           alarm(TIMEOUT);
154           errno = save_errno;
155 }
156 
157 void
tsa2sa(struct sockaddr * sa,const struct talkd_sockaddr * tsa)158 tsa2sa(struct sockaddr *sa, const struct talkd_sockaddr *tsa)
159 {
160           (void)memcpy(sa, tsa, sizeof(*tsa));
161           sa->sa_len = sizeof(*tsa);
162           sa->sa_family = tsa->sa_family;
163 }
164