Home | History | Annotate | Line # | Download | only in talk
ctl_transact.c revision 1.9 
      1 /*	$NetBSD: ctl_transact.c,v 1.9 2003/08/07 11:16:03 agc Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1983, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)ctl_transact.c	8.1 (Berkeley) 6/6/93";
     36 #endif
     37 __RCSID("$NetBSD: ctl_transact.c,v 1.9 2003/08/07 11:16:03 agc Exp $");
     38 #endif /* not lint */
     39 
     40 #include "talk.h"
     41 #include <sys/time.h>
     42 #include <errno.h>
     43 #include <unistd.h>
     44 #include <poll.h>
     45 #include "talk_ctl.h"
     46 
     47 #define CTL_WAIT 2	/* time to wait for a response, in seconds */
     48 
     49 /*
     50  * SOCKDGRAM is unreliable, so we must repeat messages if we have
     51  * not received an acknowledgement within a reasonable amount
     52  * of time
     53  */
     54 void
     55 ctl_transact(target, msg, type, rp)
     56 	struct in_addr target;
     57 	CTL_MSG msg;
     58 	int type;
     59 	CTL_RESPONSE *rp;
     60 {
     61 	struct pollfd set[1];
     62 	int nready, cc;
     63 
     64 	nready = 0;
     65 	msg.type = type;
     66 	daemon_addr.sin_addr = target;
     67 	daemon_addr.sin_port = daemon_port;
     68 	set[0].fd = ctl_sockt;
     69 	set[0].events = POLLIN;
     70 
     71 	/*
     72 	 * Keep sending the message until a response of
     73 	 * the proper type is obtained.
     74 	 */
     75 	do {
     76 		/* resend message until a response is obtained */
     77 		do {
     78 			cc = sendto(ctl_sockt, (char *)&msg, sizeof (msg), 0,
     79 			    (struct sockaddr *)&daemon_addr,
     80 			    sizeof (daemon_addr));
     81 			if (cc != sizeof (msg)) {
     82 				if (errno == EINTR)
     83 					continue;
     84 				p_error("Error on write to talk daemon");
     85 			}
     86 			nready = poll(set, 1, CTL_WAIT * 1000);
     87 			if (nready < 0) {
     88 				if (errno == EINTR)
     89 					continue;
     90 				p_error("Error waiting for daemon response");
     91 			}
     92 		} while (nready == 0);
     93 		/*
     94 		 * Keep reading while there are queued messages
     95 		 * (this is not necessary, it just saves extra
     96 		 * request/acknowledgements being sent)
     97 		 */
     98 		do {
     99 			cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
    100 			if (cc < 0) {
    101 				if (errno == EINTR)
    102 					continue;
    103 				p_error("Error on read from talk daemon");
    104 			}
    105 			/* an immediate poll */
    106 			nready = poll(set, 1, 0);
    107 		} while (nready > 0 && (rp->vers != TALK_VERSION ||
    108 		    rp->type != type));
    109 	} while (rp->vers != TALK_VERSION || rp->type != type);
    110 	rp->id_num = ntohl(rp->id_num);
    111 	rp->addr.sa_family = ntohs(rp->addr.sa_family);
    112 }
    113