xref: /netbsd/usr.bin/talk/get_addrs.c (revision 43e4027d)
1 /*	$NetBSD: get_addrs.c,v 1.12 2015/06/16 22:54:11 christos 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 #if 0
35 static char sccsid[] = "@(#)get_addrs.c	8.1 (Berkeley) 6/6/93";
36 #endif
37 __RCSID("$NetBSD: get_addrs.c,v 1.12 2015/06/16 22:54:11 christos Exp $");
38 #endif /* not lint */
39 
40 #include "talk.h"
41 #include <netdb.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <unistd.h>
45 #include <err.h>
46 #include "talk_ctl.h"
47 
48 void
get_addrs(const char * my_machine_name,const char * his_machine_name)49 get_addrs(const char *my_machine_name, const char *his_machine_name)
50 {
51 	struct hostent *hp;
52 	struct servent *sp;
53 
54 	msg.pid = htonl(getpid());
55 	/*
56 	 * If the callee is on-machine, just use loopback
57 	 * otherwise do a lookup...
58 	 */
59 	if (strcmp(his_machine_name, my_machine_name) != 0) {
60 		/* look up the address of the local host */
61 		hp = gethostbyname(my_machine_name);
62 		if (hp == NULL)
63 			errx(EXIT_FAILURE, "%s: %s", my_machine_name,
64 			    hstrerror(h_errno));
65 		memcpy(&my_machine_addr, hp->h_addr, sizeof(my_machine_addr));
66 		hp = gethostbyname(his_machine_name);
67 		if (hp == NULL)
68 			errx(EXIT_FAILURE, "%s: %s", his_machine_name,
69 			    hstrerror(h_errno));
70 		memcpy(&his_machine_addr, hp->h_addr, sizeof(his_machine_addr));
71 	} else
72 		his_machine_addr.s_addr = my_machine_addr.s_addr =
73 		    htonl(INADDR_LOOPBACK);
74 
75 	/* find the server's port */
76 	sp = getservbyname("ntalk", "udp");
77 	if (sp == 0)
78 		errx(EXIT_FAILURE, "%s/%s: service is not registered.",
79 		     "ntalk", "udp");
80 	daemon_port = sp->s_port;
81 }
82