xref: /freebsd/usr.bin/talk/get_names.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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 
34 __FBSDID("$FreeBSD$");
35 
36 #ifndef lint
37 static const char sccsid[] = "@(#)get_names.c	8.1 (Berkeley) 6/6/93";
38 #endif
39 
40 #include <sys/param.h>
41 
42 #include <err.h>
43 #include <pwd.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <unistd.h>
47 
48 #include "talk.h"
49 
50 extern	CTL_MSG msg;
51 
52 static void
53 usage(void)
54 {
55 	fprintf(stderr, "usage: talk person [ttyname]\n");
56 	exit(1);
57 }
58 
59 /*
60  * Determine the local and remote user, tty, and machines
61  */
62 void
63 get_names(int argc, char *argv[])
64 {
65 	char hostname[MAXHOSTNAMELEN];
66 	char *his_name, *my_name;
67 	const char *my_machine_name, *his_machine_name;
68 	const char *his_tty;
69 	char *cp;
70 
71 	if (argc < 2 )
72 		usage();
73 	if (!isatty(0))
74 		errx(1, "standard input must be a tty, not a pipe or a file");
75 	if ((my_name = getlogin()) == NULL) {
76 		struct passwd *pw;
77 
78 		if ((pw = getpwuid(getuid())) == NULL)
79 			errx(1, "you don't exist. Go away");
80 		my_name = pw->pw_name;
81 	}
82 	gethostname(hostname, sizeof (hostname));
83 	my_machine_name = hostname;
84 	/* check for, and strip out, the machine name of the target */
85 	cp = argv[1] + strcspn(argv[1], "@:!");
86 	if (*cp == '\0') {
87 		/* this is a local to local talk */
88 		his_name = argv[1];
89 		my_machine_name = his_machine_name = "localhost";
90 	} else {
91 		if (*cp++ == '@') {
92 			/* user@host */
93 			his_name = argv[1];
94 			his_machine_name = cp;
95 		} else {
96 			/* host!user or host:user */
97 			his_name = cp;
98 			his_machine_name = argv[1];
99 		}
100 		*--cp = '\0';
101 	}
102 	if (argc > 2)
103 		his_tty = argv[2];	/* tty name is arg 2 */
104 	else
105 		his_tty = "";
106 	get_addrs(my_machine_name, his_machine_name);
107 	/*
108 	 * Initialize the message template.
109 	 */
110 	msg.vers = TALK_VERSION;
111 	msg.addr.sa_family = htons(AF_INET);
112 	msg.ctl_addr.sa_family = htons(AF_INET);
113 	msg.id_num = htonl(0);
114 	strlcpy(msg.l_name, my_name, NAME_SIZE);
115 	strlcpy(msg.r_name, his_name, NAME_SIZE);
116 	strlcpy(msg.r_tty, his_tty, TTY_SIZE);
117 }
118