xref: /freebsd/usr.bin/talk/get_names.c (revision 42c159fe388a3765f69860c84183700af37aca8a)
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("$FreeBSD$");
37 
38 #ifndef lint
39 static 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 
51 extern	CTL_MSG msg;
52 
53 static void
54 usage(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  */
63 void
64 get_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