1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  *
22  * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T
28  * All Rights Reserved.
29  */
30 
31 /*
32  * University Copyright- Copyright (c) 1982, 1986, 1988
33  * The Regents of the University of California.
34  * All Rights Reserved.
35  *
36  * University Acknowledgment- Portions of this document are derived from
37  * software developed by the University of California, Berkeley, and its
38  * contributors.
39  */
40 
41 #pragma ident	"%Z%%M%	%I%	%E% SMI"
42 
43 /*
44  * Invoked by the Internet daemon to handle talk requests
45  * Processes talk requests until MAX_LIFE seconds go by with
46  * no action, then dies.
47  */
48 
49 #include <stdio.h>
50 #include <errno.h>
51 #include <sys/ioctl.h>
52 #include <sys/time.h>
53 #include <sys/systeminfo.h>
54 #include <sys/wait.h>
55 #include <unistd.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include "talkd_impl.h"
59 
60 static CTL_MSG request;
61 static CTL_RESPONSE response;
62 
63 char hostname[HOST_NAME_LENGTH];
64 int debug = 0;
65 
66 static CTL_MSG swapmsg(CTL_MSG req);
67 
68 int
main()69 main()
70 {
71 	struct sockaddr_in from;
72 	socklen_t from_size = (socklen_t)sizeof (from);
73 	int cc;
74 	int name_length = sizeof (hostname);
75 	fd_set rfds;
76 	struct timeval tv;
77 
78 	(void) sysinfo(SI_HOSTNAME, hostname, name_length);
79 
80 	for (;;) {
81 		tv.tv_sec = MAX_LIFE;
82 		tv.tv_usec = 0;
83 		FD_ZERO(&rfds);
84 		FD_SET(0, &rfds);
85 		if (select(1, &rfds, 0, 0, &tv) <= 0)
86 			return (0);
87 		cc = recvfrom(0, (char *)&request, sizeof (request), 0,
88 		    (struct sockaddr *)&from, &from_size);
89 
90 		if (cc != sizeof (request)) {
91 			if (cc < 0 && errno != EINTR) {
92 				print_error("receive");
93 			}
94 		} else {
95 
96 			if (debug) {
97 				(void) printf("Request received : \n");
98 				(void) print_request(&request);
99 			}
100 
101 			request = swapmsg(request);
102 			process_request(&request, &response);
103 
104 			if (debug) {
105 				(void) printf("Response sent : \n");
106 				print_response(&response);
107 			}
108 
109 			/*
110 			 * Can block here, is this what I want?
111 			 */
112 			cc = sendto(0, (char *)&response, sizeof (response), 0,
113 			    (struct sockaddr *)&request.ctl_addr,
114 			    (socklen_t)sizeof (request.ctl_addr));
115 
116 			if (cc != sizeof (response)) {
117 				print_error("Send");
118 			}
119 		}
120 	}
121 }
122 
123 void
print_error(char * string)124 print_error(char *string)
125 {
126 	FILE *cons;
127 	char *err_dev = "/dev/console";
128 	char *sys;
129 	pid_t val, pid;
130 
131 	if (debug)
132 		err_dev = "/dev/tty";
133 
134 	if ((sys = strerror(errno)) == (char *)NULL)
135 	    sys = "Unknown error";
136 
137 	/* don't ever open tty's directly, let a child do it */
138 	if ((pid = fork()) == 0) {
139 		cons = fopen(err_dev, "a");
140 		if (cons != NULL) {
141 			(void) fprintf(cons, "Talkd : %s : %s(%d)\n\r", string,
142 			    sys, errno);
143 			(void) fclose(cons);
144 		}
145 		exit(0);
146 	} else {
147 		/* wait for the child process to return */
148 		do {
149 			val = wait(0);
150 			if (val == (pid_t)-1) {
151 				if (errno == EINTR) {
152 					continue;
153 				} else if (errno == ECHILD) {
154 					break;
155 				}
156 			}
157 		} while (val != pid);
158 	}
159 }
160 
161 #define	swapshort(a) (((a << 8) | ((unsigned short) a >> 8)) & 0xffff)
162 #define	swaplong(a) ((swapshort(a) << 16) | (swapshort(((unsigned)a >> 16))))
163 
164 /*
165  * Heuristic to detect if need to swap bytes.
166  */
167 
168 static CTL_MSG
swapmsg(CTL_MSG req)169 swapmsg(CTL_MSG req)
170 {
171 	CTL_MSG swapreq;
172 
173 	if (req.ctl_addr.sin_family == swapshort(AF_INET)) {
174 		swapreq = req;
175 		swapreq.id_num = swaplong(req.id_num);
176 		swapreq.pid = swaplong(req.pid);
177 		swapreq.addr.sin_family = swapshort(req.addr.sin_family);
178 		swapreq.ctl_addr.sin_family =
179 			swapshort(req.ctl_addr.sin_family);
180 		return (swapreq);
181 	} else {
182 		return (req);
183 	}
184 }
185