get_names.c revision 87710 
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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35
36__FBSDID("$FreeBSD: head/usr.bin/talk/get_names.c 87710 2001-12-11 23:51:14Z markm $");
37
38#ifndef lint
39static const char sccsid[] = "@(#)get_names.c	8.1 (Berkeley) 6/6/93";
40#endif
41
42#include <sys/param.h>
43
44#include <err.h>
45#include <pwd.h>
46#include <stdlib.h>
47#include <string.h>
48
49#include "talk.h"
50
51extern	CTL_MSG msg;
52
53static void
54usage(void)
55{
56	fprintf(stderr, "usage: talk person [ttyname]\n");
57	exit(1);
58}
59
60/*
61 * Determine the local and remote user, tty, and machines
62 */
63void
64get_names(argc, argv)
65	int argc;
66	char *argv[];
67{
68	char hostname[MAXHOSTNAMELEN];
69	char *his_name, *my_name;
70	char *my_machine_name, *his_machine_name;
71	const char *his_tty;
72	char *cp;
73
74	if (argc < 2 )
75		usage();
76	if (!isatty(0))
77		errx(1, "standard input must be a tty, not a pipe or a file");
78	if ((my_name = getlogin()) == NULL) {
79		struct passwd *pw;
80
81		if ((pw = getpwuid(getuid())) == NULL)
82			errx(1, "you don't exist. Go away");
83		my_name = pw->pw_name;
84	}
85	gethostname(hostname, sizeof (hostname));
86	my_machine_name = hostname;
87	/* check for, and strip out, the machine name of the target */
88	for (cp = argv[1]; *cp && !index("@:!", *cp); cp++)
89		;
90	if (*cp == '\0') {
91		/* this is a local to local talk */
92		his_name = argv[1];
93		his_machine_name = my_machine_name;
94	} else {
95		if (*cp++ == '@') {
96			/* user@host */
97			his_name = argv[1];
98			his_machine_name = cp;
99		} else {
100			/* host!user or host:user */
101			his_name = cp;
102			his_machine_name = argv[1];
103		}
104		*--cp = '\0';
105	}
106	if (argc > 2)
107		his_tty = argv[2];	/* tty name is arg 2 */
108	else
109		his_tty = "";
110	get_addrs(my_machine_name, his_machine_name);
111	/*
112	 * Initialize the message template.
113	 */
114	msg.vers = TALK_VERSION;
115	msg.addr.sa_family = htons(AF_INET);
116	msg.ctl_addr.sa_family = htons(AF_INET);
117	msg.id_num = htonl(0);
118	strncpy(msg.l_name, my_name, NAME_SIZE);
119	msg.l_name[NAME_SIZE - 1] = '\0';
120	strncpy(msg.r_name, his_name, NAME_SIZE);
121	msg.r_name[NAME_SIZE - 1] = '\0';
122	strncpy(msg.r_tty, his_tty, TTY_SIZE);
123	msg.r_tty[TTY_SIZE - 1] = '\0';
124}
125