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      1 /*	$NetBSD: get_names.c,v 1.16 2012/12/29 23:44:23 christos Exp $	*/
      2 
      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 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)get_names.c	8.1 (Berkeley) 6/6/93";
     36 #endif
     37 __RCSID("$NetBSD: get_names.c,v 1.16 2012/12/29 23:44:23 christos Exp $");
     38 #endif /* not lint */
     39 
     40 #include "talk.h"
     41 #include <err.h>
     42 #include <sys/param.h>
     43 #include <pwd.h>
     44 #include <stdlib.h>
     45 #include <unistd.h>
     46 #include <util.h>
     47 
     48 extern	CTL_MSG msg;
     49 
     50 /*
     51  * Determine the local and remote user, tty, and machines
     52  */
     53 void
     54 get_names(int argc, char *argv[])
     55 {
     56 	char hostname[MAXHOSTNAMELEN + 1];
     57 	const char *his_name, *my_name;
     58 	const char *my_machine_name, *his_machine_name;
     59 	const char *his_tty;
     60 	char *cp;
     61 	char *names;
     62 
     63 	if (argc < 2 ) {
     64 		fprintf(stderr, "Usage: %s user [ttyname]\n", getprogname());
     65 		exit(1);
     66 	}
     67 	if (!isatty(0))
     68 		errx(EXIT_FAILURE, "Standard input must be a tty, "
     69 		    "not a pipe or a file");
     70 	if ((my_name = getlogin()) == NULL) {
     71 		struct passwd *pw;
     72 
     73 		if ((pw = getpwuid(getuid())) == NULL)
     74 			errx(EXIT_FAILURE, "You don't exist. Go away.");
     75 		my_name = pw->pw_name;
     76 	}
     77 	if ((cp = getenv("TALKHOST")) != NULL)
     78 		(void)estrlcpy(hostname, cp, sizeof(hostname));
     79 	else {
     80 		if (gethostname(hostname, sizeof(hostname)) == -1)
     81 			err(EXIT_FAILURE, "gethostname");
     82 		hostname[sizeof(hostname) - 1] = '\0';
     83 	}
     84 	my_machine_name = hostname;
     85 	/* check for, and strip out, the machine name of the target */
     86 	names = strdup(argv[1]);
     87 	for (cp = names; *cp && !strchr("@:!.", *cp); cp++)
     88 		;
     89 	if (*cp == '\0') {
     90 		/* this is a local to local talk */
     91 		his_name = names;
     92 		his_machine_name = my_machine_name;
     93 	} else {
     94 		if (*cp++ == '@') {
     95 			/* user@host */
     96 			his_name = names;
     97 			his_machine_name = cp;
     98 		} else {
     99 			/* host.user or host!user or host:user */
    100 			his_name = cp;
    101 			his_machine_name = names;
    102 		}
    103 		*--cp = '\0';
    104 	}
    105 	if (argc > 2)
    106 		his_tty = argv[2];	/* tty name is arg 2 */
    107 	else
    108 		his_tty = "";
    109 	get_addrs(my_machine_name, his_machine_name);
    110 	/*
    111 	 * Initialize the message template.
    112 	 */
    113 	msg.vers = TALK_VERSION;
    114 	msg.addr.sa_family = htons(AF_INET);
    115 	msg.ctl_addr.sa_family = htons(AF_INET);
    116 	msg.id_num = htonl(0);
    117 	strncpy(msg.l_name, my_name, NAME_SIZE);
    118 	msg.l_name[NAME_SIZE - 1] = '\0';
    119 	strncpy(msg.r_name, his_name, NAME_SIZE);
    120 	msg.r_name[NAME_SIZE - 1] = '\0';
    121 	strncpy(msg.r_tty, his_tty, TTY_SIZE);
    122 	msg.r_tty[TTY_SIZE - 1] = '\0';
    123 	free(names);
    124 }
    125