inetutils/talk/ctl_transact.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 <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <time.h>
#include <netinet/in.h>
#include <sys/select.h>
#include <protocols/talkd.h>
#include <errno.h>
#include "talk_ctl.h"
#include "talk.h"

#define CTL_WAIT 2		/* time to wait for a response, in seconds */

/*
 * SOCKDGRAM is unreliable, so we must repeat messages if we have
 * not received an acknowledgement within a reasonable amount
 * of time
 */
int
ctl_transact (struct in_addr target, CTL_MSG msg, int type, CTL_RESPONSE *rp)
{
  int nready = 0, cc;
  fd_set read_mask, ctl_mask;
  struct timeval wait;

  msg.type = type;
  daemon_addr.sin_family = AF_INET;
#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
  daemon_addr.sin_len = sizeof (daemon_addr);
#endif
  daemon_addr.sin_addr = target;
  daemon_addr.sin_port = htons (daemon_port);
  FD_ZERO (&ctl_mask);
  FD_SET (ctl_sockt, &ctl_mask);

  /*
   * Keep sending the message until a response of
   * the proper type is obtained.
   */
  do
    {
      wait.tv_sec = CTL_WAIT;
      wait.tv_usec = 0;
      /* resend message until a response is obtained */
      do
	{
	  cc = sendto (ctl_sockt, (char *) &msg, sizeof (msg), 0,
		       (struct sockaddr *) &daemon_addr,
		       sizeof (daemon_addr));
	  if (cc != sizeof (msg))
	    {
	      if (errno == EINTR)
		continue;
	      p_error ("Error on write to talk daemon");
	    }
	  read_mask = ctl_mask;
	  nready = select (32, &read_mask, 0, 0, &wait);
	  if (nready < 0)
	    {
	      if (errno == EINTR)
		continue;
	      p_error ("Error waiting for daemon response");
	    }
	}
      while (nready == 0);
      /*
       * Keep reading while there are queued messages
       * (this is not necessary, it just saves extra
       * request/acknowledgements being sent)
       */
      do
	{
	  cc = recv (ctl_sockt, (char *) rp, sizeof (*rp), 0);
	  if (cc < 0)
	    {
	      if (errno == EINTR)
		continue;
	      p_error ("Error on read from talk daemon");
	    }
	  read_mask = ctl_mask;
	  /* an immediate poll */
	  timerclear (&wait);
	  nready = select (32, &read_mask, 0, 0, &wait);
	}
      while (nready > 0 && (rp->vers != TALK_VERSION || rp->type != type));
    }
  while (rp->vers != TALK_VERSION || rp->type != type);
  rp->id_num = ntohl (rp->id_num);
  rp->addr.sa_family = ntohs (rp->addr.sa_family);

  return 0;
}