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ctl_transact.c revision 1.7 
      1 /*	$NetBSD: ctl_transact.c,v 1.7 2002/09/23 03:30:20 itojun 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #ifndef lint
     38 #if 0
     39 static char sccsid[] = "@(#)ctl_transact.c	8.1 (Berkeley) 6/6/93";
     40 #endif
     41 __RCSID("$NetBSD: ctl_transact.c,v 1.7 2002/09/23 03:30:20 itojun Exp $");
     42 #endif /* not lint */
     43 
     44 #include "talk.h"
     45 #include <sys/time.h>
     46 #include <errno.h>
     47 #include <unistd.h>
     48 #include <poll.h>
     49 #include "talk_ctl.h"
     50 
     51 #define CTL_WAIT 2	/* time to wait for a response, in seconds */
     52 
     53 /*
     54  * SOCKDGRAM is unreliable, so we must repeat messages if we have
     55  * not received an acknowledgement within a reasonable amount
     56  * of time
     57  */
     58 void
     59 ctl_transact(target, msg, type, rp)
     60 	struct in_addr target;
     61 	CTL_MSG msg;
     62 	int type;
     63 	CTL_RESPONSE *rp;
     64 {
     65 	struct pollfd set[1];
     66 	int nready, cc;
     67 
     68 	nready = 0;
     69 	msg.type = type;
     70 	daemon_addr.sin_addr = target;
     71 	daemon_addr.sin_port = daemon_port;
     72 	set[0].fd = ctl_sockt;
     73 	set[0].events = POLLIN;
     74 
     75 	/*
     76 	 * Keep sending the message until a response of
     77 	 * the proper type is obtained.
     78 	 */
     79 	do {
     80 		/* resend message until a response is obtained */
     81 		do {
     82 			cc = sendto(ctl_sockt, (char *)&msg, sizeof (msg), 0,
     83 			    (struct sockaddr *)&daemon_addr,
     84 			    sizeof (daemon_addr));
     85 			if (cc != sizeof (msg)) {
     86 				if (errno == EINTR)
     87 					continue;
     88 				p_error("Error on write to talk daemon");
     89 			}
     90 			nready = poll(set, 1, CTL_WAIT * 1000);
     91 			if (nready < 0) {
     92 				if (errno == EINTR)
     93 					continue;
     94 				p_error("Error waiting for daemon response");
     95 			}
     96 		} while (nready == 0);
     97 		/*
     98 		 * Keep reading while there are queued messages
     99 		 * (this is not necessary, it just saves extra
    100 		 * request/acknowledgements being sent)
    101 		 */
    102 		do {
    103 			cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
    104 			if (cc < 0) {
    105 				if (errno == EINTR)
    106 					continue;
    107 				p_error("Error on read from talk daemon");
    108 			}
    109 			/* an immediate poll */
    110 			nready = poll(set, 1, 0);
    111 		} while (nready > 0 && (rp->vers != TALK_VERSION ||
    112 		    rp->type != type));
    113 	} while (rp->vers != TALK_VERSION || rp->type != type);
    114 	rp->id_num = ntohl(rp->id_num);
    115 	rp->addr.sa_family = ntohs(rp->addr.sa_family);
    116 }
    117