get_names.c revision 331722 
1/*
2 * Copyright (c) 1983, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31
32__FBSDID("$FreeBSD: stable/11/usr.bin/talk/get_names.c 331722 2018-03-29 02:50:57Z eadler $");
33
34#ifndef lint
35static const char sccsid[] = "@(#)get_names.c	8.1 (Berkeley) 6/6/93";
36#endif
37
38#include <sys/param.h>
39
40#include <err.h>
41#include <pwd.h>
42#include <stdlib.h>
43#include <string.h>
44#include <unistd.h>
45
46#include "talk.h"
47
48extern	CTL_MSG msg;
49
50static void
51usage(void)
52{
53	fprintf(stderr, "usage: talk person [ttyname]\n");
54	exit(1);
55}
56
57/*
58 * Determine the local and remote user, tty, and machines
59 */
60void
61get_names(int argc, char *argv[])
62{
63	char hostname[MAXHOSTNAMELEN];
64	char *his_name, *my_name;
65	const char *my_machine_name, *his_machine_name;
66	const char *his_tty;
67	char *cp;
68
69	if (argc < 2 )
70		usage();
71	if (!isatty(0))
72		errx(1, "standard input must be a tty, not a pipe or a file");
73	if ((my_name = getlogin()) == NULL) {
74		struct passwd *pw;
75
76		if ((pw = getpwuid(getuid())) == NULL)
77			errx(1, "you don't exist. Go away");
78		my_name = pw->pw_name;
79	}
80	gethostname(hostname, sizeof (hostname));
81	my_machine_name = hostname;
82	/* check for, and strip out, the machine name of the target */
83	cp = argv[1] + strcspn(argv[1], "@:!");
84	if (*cp == '\0') {
85		/* this is a local to local talk */
86		his_name = argv[1];
87		my_machine_name = his_machine_name = "localhost";
88	} else {
89		if (*cp++ == '@') {
90			/* user@host */
91			his_name = argv[1];
92			his_machine_name = cp;
93		} else {
94			/* host!user or host:user */
95			his_name = cp;
96			his_machine_name = argv[1];
97		}
98		*--cp = '\0';
99	}
100	if (argc > 2)
101		his_tty = argv[2];	/* tty name is arg 2 */
102	else
103		his_tty = "";
104	get_addrs(my_machine_name, his_machine_name);
105	/*
106	 * Initialize the message template.
107	 */
108	msg.vers = TALK_VERSION;
109	msg.addr.sa_family = htons(AF_INET);
110	msg.ctl_addr.sa_family = htons(AF_INET);
111	msg.id_num = htonl(0);
112	strlcpy(msg.l_name, my_name, NAME_SIZE);
113	strlcpy(msg.r_name, his_name, NAME_SIZE);
114	strlcpy(msg.r_tty, his_tty, TTY_SIZE);
115}
116