NetBSD/usr.bin/talk/ctl_transact.c

/*	$NetBSD: ctl_transact.c,v 1.11 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[] = "@(#)ctl_transact.c	8.1 (Berkeley) 6/6/93";
#endif
__RCSID("$NetBSD: ctl_transact.c,v 1.11 2011/09/06 18:32:03 joerg Exp $");
#endif /* not lint */

#include "talk.h"
#include <sys/time.h>
#include <errno.h>
#include <unistd.h>
#include <poll.h>
#include "talk_ctl.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
 */
void
ctl_transact(struct in_addr target, CTL_MSG tmsg, int type, CTL_RESPONSE *rp)
{
	struct pollfd set[1];
	int nready, cc;

	nready = 0;
	tmsg.type = type;
	daemon_addr.sin_addr = target;
	daemon_addr.sin_port = daemon_port;
	set[0].fd = ctl_sockt;
	set[0].events = POLLIN;

	/*
	 * Keep sending the message until a response of
	 * the proper type is obtained.
	 */
	do {
		/* resend message until a response is obtained */
		do {
			cc = sendto(ctl_sockt, (char *)&tmsg, sizeof (tmsg), 0,
			    (struct sockaddr *)&daemon_addr,
			    sizeof (daemon_addr));
			if (cc != sizeof (tmsg)) {
				if (errno == EINTR)
					continue;
				p_error("Error on write to talk daemon");
			}
			nready = poll(set, 1, CTL_WAIT * 1000);
			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");
			}
			/* an immediate poll */
			nready = poll(set, 1, 0);
		} 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);
}