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
33
34#include <sys/param.h>
35
36#include <err.h>
37#include <pwd.h>
38#include <stdlib.h>
39#include <string.h>
40#include <unistd.h>
41
42#include "talk.h"
43
44extern	CTL_MSG msg;
45
46static void
47usage(void)
48{
49	fprintf(stderr, "usage: talk person [ttyname]\n");
50	exit(1);
51}
52
53/*
54 * Determine the local and remote user, tty, and machines
55 */
56void
57get_names(int argc, char *argv[])
58{
59	char hostname[MAXHOSTNAMELEN];
60	char *his_name, *my_name;
61	const char *my_machine_name, *his_machine_name;
62	const char *his_tty;
63	char *cp;
64
65	if (argc < 2 )
66		usage();
67	if (!isatty(0))
68		errx(1, "standard input must be a tty, not a pipe or a file");
69	if ((my_name = getlogin()) == NULL) {
70		struct passwd *pw;
71
72		if ((pw = getpwuid(getuid())) == NULL)
73			errx(1, "you don't exist. Go away");
74		my_name = pw->pw_name;
75	}
76	gethostname(hostname, sizeof (hostname));
77	my_machine_name = hostname;
78	/* check for, and strip out, the machine name of the target */
79	cp = argv[1] + strcspn(argv[1], "@:!");
80	if (*cp == '\0') {
81		/* this is a local to local talk */
82		his_name = argv[1];
83		my_machine_name = his_machine_name = "localhost";
84	} else {
85		if (*cp++ == '@') {
86			/* user@host */
87			his_name = argv[1];
88			his_machine_name = cp;
89		} else {
90			/* host!user or host:user */
91			his_name = cp;
92			his_machine_name = argv[1];
93		}
94		*--cp = '\0';
95	}
96	if (argc > 2)
97		his_tty = argv[2];	/* tty name is arg 2 */
98	else
99		his_tty = "";
100	get_addrs(my_machine_name, his_machine_name);
101	/*
102	 * Initialize the message template.
103	 */
104	msg.vers = TALK_VERSION;
105	msg.addr.sa_family = htons(AF_INET);
106	msg.ctl_addr.sa_family = htons(AF_INET);
107	msg.id_num = htonl(0);
108	strlcpy(msg.l_name, my_name, NAME_SIZE);
109	strlcpy(msg.r_name, his_name, NAME_SIZE);
110	strlcpy(msg.r_tty, his_tty, TTY_SIZE);
111}
112