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      1 /*	$NetBSD: ctl_transact.c,v 1.11 2011/09/06 18:32:03 joerg 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 1.11 2011/09/06 18:32:03 joerg 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(struct in_addr target, CTL_MSG tmsg, int type, CTL_RESPONSE *rp)
     56 {
     57 	struct pollfd set[1];
     58 	int nready, cc;
     59 
     60 	nready = 0;
     61 	tmsg.type = type;
     62 	daemon_addr.sin_addr = target;
     63 	daemon_addr.sin_port = daemon_port;
     64 	set[0].fd = ctl_sockt;
     65 	set[0].events = POLLIN;
     66 
     67 	/*
     68 	 * Keep sending the message until a response of
     69 	 * the proper type is obtained.
     70 	 */
     71 	do {
     72 		/* resend message until a response is obtained */
     73 		do {
     74 			cc = sendto(ctl_sockt, (char *)&tmsg, sizeof (tmsg), 0,
     75 			    (struct sockaddr *)&daemon_addr,
     76 			    sizeof (daemon_addr));
     77 			if (cc != sizeof (tmsg)) {
     78 				if (errno == EINTR)
     79 					continue;
     80 				p_error("Error on write to talk daemon");
     81 			}
     82 			nready = poll(set, 1, CTL_WAIT * 1000);
     83 			if (nready < 0) {
     84 				if (errno == EINTR)
     85 					continue;
     86 				p_error("Error waiting for daemon response");
     87 			}
     88 		} while (nready == 0);
     89 		/*
     90 		 * Keep reading while there are queued messages
     91 		 * (this is not necessary, it just saves extra
     92 		 * request/acknowledgements being sent)
     93 		 */
     94 		do {
     95 			cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
     96 			if (cc < 0) {
     97 				if (errno == EINTR)
     98 					continue;
     99 				p_error("Error on read from talk daemon");
    100 			}
    101 			/* an immediate poll */
    102 			nready = poll(set, 1, 0);
    103 		} while (nready > 0 && (rp->vers != TALK_VERSION ||
    104 		    rp->type != type));
    105 	} while (rp->vers != TALK_VERSION || rp->type != type);
    106 	rp->id_num = ntohl(rp->id_num);
    107 	rp->addr.sa_family = ntohs(rp->addr.sa_family);
    108 }
    109