NetBSD/usr.bin/talk/get_names.c

/*	$NetBSD: get_names.c,v 1.15 2011/09/06 18:32:03 joerg Exp $	*/

/*
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)get_names.c	8.1 (Berkeley) 6/6/93";
#endif
__RCSID("$NetBSD: get_names.c,v 1.15 2011/09/06 18:32:03 joerg Exp $");
#endif /* not lint */

#include "talk.h"
#include <err.h>
#include <sys/param.h>
#include <pwd.h>
#include <stdlib.h>
#include <unistd.h>
#include <util.h>

extern	CTL_MSG msg;

/*
 * Determine the local and remote user, tty, and machines
 */
void
get_names(int argc, char *argv[])
{
	char hostname[MAXHOSTNAMELEN + 1];
	const char *his_name, *my_name;
	const char *my_machine_name, *his_machine_name;
	const char *his_tty;
	char *cp;
	char *names;

	if (argc < 2 ) {
		printf("usage: talk user [ttyname]\n");
		exit(1);
	}
	if (!isatty(0)) {
		printf("Standard input must be a tty, not a pipe or a file\n");
		exit(1);
	}
	if ((my_name = getlogin()) == NULL) {
		struct passwd *pw;

		if ((pw = getpwuid(getuid())) == NULL) {
			printf("You don't exist. Go away.\n");
			exit(1);
		}
		my_name = pw->pw_name;
	}
	if ((cp = getenv("TALKHOST")) != NULL)
		(void)estrlcpy(hostname, cp, sizeof(hostname));
	else {
		if (gethostname(hostname, sizeof(hostname)) == -1)
			err(EXIT_FAILURE, "gethostname");
		hostname[sizeof(hostname) - 1] = '\0';
	}
	my_machine_name = hostname;
	/* check for, and strip out, the machine name of the target */
	names = strdup(argv[1]);
	for (cp = names; *cp && !strchr("@:!.", *cp); cp++)
		;
	if (*cp == '\0') {
		/* this is a local to local talk */
		his_name = names;
		his_machine_name = my_machine_name;
	} else {
		if (*cp++ == '@') {
			/* user@host */
			his_name = names;
			his_machine_name = cp;
		} else {
			/* host.user or host!user or host:user */
			his_name = cp;
			his_machine_name = names;
		}
		*--cp = '\0';
	}
	if (argc > 2)
		his_tty = argv[2];	/* tty name is arg 2 */
	else
		his_tty = "";
	get_addrs(my_machine_name, his_machine_name);
	/*
	 * Initialize the message template.
	 */
	msg.vers = TALK_VERSION;
	msg.addr.sa_family = htons(AF_INET);
	msg.ctl_addr.sa_family = htons(AF_INET);
	msg.id_num = htonl(0);
	strncpy(msg.l_name, my_name, NAME_SIZE);
	msg.l_name[NAME_SIZE - 1] = '\0';
	strncpy(msg.r_name, his_name, NAME_SIZE);
	msg.r_name[NAME_SIZE - 1] = '\0';
	strncpy(msg.r_tty, his_tty, TTY_SIZE);
	msg.r_tty[TTY_SIZE - 1] = '\0';
	free(names);
}