1 /* $OpenBSD: talkd.c,v 1.21 2004/08/08 19:32:45 deraadt Exp $ */
2
3 /*
4 * Copyright (c) 1983 Regents of the University of California.
5 * 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 char copyright[] =
34 "@(#) Copyright (c) 1983 Regents of the University of California.\n\
35 All rights reserved.\n";
36 #endif /* not lint */
37
38 #ifndef lint
39 /*static char sccsid[] = "from: @(#)talkd.c 5.8 (Berkeley) 2/26/91";*/
40 static char rcsid[] = "$Id: talkd.c,v 1.21 2004/08/08 19:32:45 deraadt Exp $";
41 #endif /* not lint */
42
43 /*
44 * The top level of the daemon, the format is heavily borrowed
45 * from rwhod.c. Basically: find out who and where you are;
46 * disconnect all descriptors and ttys, and then endless
47 * loop on waiting for and processing requests
48 */
49 #include <sys/param.h>
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 #include "talkd.h"
63
64 int debug = 0;
65 void timeout(int);
66 long lastmsgtime;
67
68 char hostname[MAXHOSTNAMELEN];
69
70 #define TIMEOUT 30
71 #define MAXIDLE 120
72
73 int
main(int argc,char * argv[])74 main(int argc, char *argv[])
75 {
76 if (getuid() != 0) {
77 fprintf(stderr, "%s: getuid: not super-user\n", argv[0]);
78 exit(1);
79 }
80 openlog("talkd", LOG_PID, LOG_DAEMON);
81 if (gethostname(hostname, sizeof(hostname)) < 0) {
82 syslog(LOG_ERR, "gethostname: %m");
83 _exit(1);
84 }
85 if (chdir(_PATH_DEV) < 0) {
86 syslog(LOG_ERR, "chdir: %s: %m", _PATH_DEV);
87 _exit(1);
88 }
89 if (argc > 1 && strcmp(argv[1], "-d") == 0)
90 debug = 1;
91 init_table();
92 signal(SIGALRM, timeout);
93 alarm(TIMEOUT);
94
95 for (;;) {
96 CTL_RESPONSE response;
97 socklen_t len = sizeof(response.addr);
98 CTL_MSG request;
99 int cc;
100 struct sockaddr ctl_addr;
101
102 memset(&response, 0, sizeof(response));
103 cc = recvfrom(STDIN_FILENO, (char *)&request,
104 sizeof(request), 0, (struct sockaddr *)&response.addr,
105 &len);
106 if (cc != sizeof(request)) {
107 if (cc < 0 && errno != EINTR)
108 syslog(LOG_WARNING, "recvfrom: %m");
109 continue;
110 }
111
112 /* Force NUL termination */
113 request.l_name[sizeof(request.l_name) - 1] = '\0';
114 request.r_name[sizeof(request.r_name) - 1] = '\0';
115 request.r_tty[sizeof(request.r_tty) - 1] = '\0';
116
117 memcpy(&ctl_addr, &request.ctl_addr, sizeof(ctl_addr));
118 ctl_addr.sa_family = ntohs(request.ctl_addr.sa_family);
119 ctl_addr.sa_len = sizeof(ctl_addr);
120 if (ctl_addr.sa_family != AF_INET)
121 continue;
122
123 lastmsgtime = time(0);
124 process_request(&request, &response);
125 /* can block here, is this what I want? */
126 cc = sendto(STDOUT_FILENO, (char *)&response,
127 sizeof(response), 0, &ctl_addr, sizeof(ctl_addr));
128 if (cc != sizeof(response))
129 syslog(LOG_WARNING, "sendto: %m");
130 }
131 }
132
133 void
timeout(int signo)134 timeout(int signo)
135 {
136 int save_errno = errno;
137
138 if (time(0) - lastmsgtime >= MAXIDLE)
139 _exit(0);
140 alarm(TIMEOUT);
141 errno = save_errno;
142 }
143