inetutils/talk/get_names.c

/*
  Copyright (C) 1995-2025 Free Software Foundation, Inc.

  This file is part of GNU Inetutils.

  GNU Inetutils is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or (at
  your option) any later version.

  GNU Inetutils is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see `http://www.gnu.org/licenses/'. */

/*
 * 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 <config.h>

#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <protocols/talkd.h>
#include <pwd.h>
#include <libinetutils.h>
#include <unistd.h>
#include "talk.h"

char *getlogin (void);
char *ttyname (int);
extern CTL_MSG msg;

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

  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;
    }

  my_machine_name = localhost ();
  if (!my_machine_name)
    {
      perror ("Cannot get local hostname");
      exit (-1);
    }

  /* check for, and strip out, the machine name of the target */
  for (cp = argv[0]; *cp && !strchr ("@:!.", *cp); cp++)
    ;
  if (*cp == '\0')
    {
      /* this is a local to local talk */
      his_name = argv[0];
      his_machine_name = my_machine_name;
    }
  else
    {
      if (*cp++ == '@')
	{
	  /* user@host */
	  his_name = argv[0];
	  his_machine_name = cp;
	}
      else
	{
	  /* host.user or host!user or host:user */
	  his_name = cp;
	  his_machine_name = argv[0];
	}
      *--cp = '\0';
    }
  if (argc > 1)
    his_tty = argv[1];		/* 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 (my_machine_name);

  return 0;
}