xref: /freebsd/usr.bin/talk/get_names.c (revision 81966bce06dac45f42bda62b14dba0756ef28505)
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("$FreeBSD$");
33 
34 #ifndef lint
35 static 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 
48 extern	CTL_MSG msg;
49 
50 static void
51 usage(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  */
60 void
61 get_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 	for (cp = argv[1]; *cp && !index("@:!", *cp); cp++)
84 		;
85 	if (*cp == '\0') {
86 		/* this is a local to local talk */
87 		his_name = argv[1];
88 		my_machine_name = his_machine_name = "localhost";
89 	} else {
90 		if (*cp++ == '@') {
91 			/* user@host */
92 			his_name = argv[1];
93 			his_machine_name = cp;
94 		} else {
95 			/* host!user or host:user */
96 			his_name = cp;
97 			his_machine_name = argv[1];
98 		}
99 		*--cp = '\0';
100 	}
101 	if (argc > 2)
102 		his_tty = argv[2];	/* tty name is arg 2 */
103 	else
104 		his_tty = "";
105 	get_addrs(my_machine_name, his_machine_name);
106 	/*
107 	 * Initialize the message template.
108 	 */
109 	msg.vers = TALK_VERSION;
110 	msg.addr.sa_family = htons(AF_INET);
111 	msg.ctl_addr.sa_family = htons(AF_INET);
112 	msg.id_num = htonl(0);
113 	strlcpy(msg.l_name, my_name, NAME_SIZE);
114 	strlcpy(msg.r_name, his_name, NAME_SIZE);
115 	strlcpy(msg.r_tty, his_tty, TTY_SIZE);
116 }
117