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freebsd/usr.bin/talk/get_names.c
Bruce M Simpson 9d61853d9f Change the default behaviour of talk(1) to use "localhost" as the
"machine name" in ntalkd(8) request packets, when the destination
and source are local.

This should make talk(1) use much more pleasant for those security-
conscious individuals who have chosen to bind talkd to "localhost".

Previous to this change, talk(1) would require that the hostname of
the machine, as retrieved by gethostname(3), resolved to a valid and
reachable IPv4 address, using gethostbyname(3).

This makes talk(1) dependent on a valid host entry for "localhost"
in /etc/hosts (or the Domain Name System).

PR:		bin/23178
Submitted by:	angui.sh admin (with cleanups)
2004-06-14 22:34:13 +00:00

125 lines
3.7 KiB
C

/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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>
__FBSDID("$FreeBSD$");
#ifndef lint
static const char sccsid[] = "@(#)get_names.c 8.1 (Berkeley) 6/6/93";
#endif
#include <sys/param.h>
#include <err.h>
#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include "talk.h"
extern CTL_MSG msg;
static void
usage(void)
{
fprintf(stderr, "usage: talk person [ttyname]\n");
exit(1);
}
/*
* Determine the local and remote user, tty, and machines
*/
void
get_names(argc, argv)
int argc;
char *argv[];
{
char hostname[MAXHOSTNAMELEN];
char *his_name, *my_name;
char *my_machine_name, *his_machine_name;
const char *his_tty;
char *cp;
if (argc < 2 )
usage();
if (!isatty(0))
errx(1, "standard input must be a tty, not a pipe or a file");
if ((my_name = getlogin()) == NULL) {
struct passwd *pw;
if ((pw = getpwuid(getuid())) == NULL)
errx(1, "you don't exist. Go away");
my_name = pw->pw_name;
}
gethostname(hostname, sizeof (hostname));
my_machine_name = hostname;
/* check for, and strip out, the machine name of the target */
for (cp = argv[1]; *cp && !index("@:!", *cp); cp++)
;
if (*cp == '\0') {
/* this is a local to local talk */
his_name = argv[1];
my_machine_name = his_machine_name = "localhost";
} else {
if (*cp++ == '@') {
/* user@host */
his_name = argv[1];
his_machine_name = cp;
} else {
/* host!user or host:user */
his_name = cp;
his_machine_name = argv[1];
}
*--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';
}