Home | History | Annotate | Line # | Download | only in talk
ctl_transact.c revision 1.2 
      1 /*
      2  * Copyright (c) 1983 Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 /*static char sccsid[] = "from: @(#)ctl_transact.c	5.8 (Berkeley) 3/1/91";*/
     36 static char rcsid[] = "$Id: ctl_transact.c,v 1.2 1993/08/01 18:07:54 mycroft Exp $";
     37 #endif /* not lint */
     38 
     39 #include <sys/types.h>
     40 #include <sys/socket.h>
     41 #include <sys/time.h>
     42 #include <netinet/in.h>
     43 #include <protocols/talkd.h>
     44 #include <errno.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 recieved an acknowledgement within a reasonable amount
     52  * of time
     53  */
     54 ctl_transact(target, msg, type, rp)
     55 	struct in_addr target;
     56 	CTL_MSG msg;
     57 	int type;
     58 	CTL_RESPONSE *rp;
     59 {
     60 	int read_mask, ctl_mask, nready, cc;
     61 	struct timeval wait;
     62 
     63 	msg.type = type;
     64 	daemon_addr.sin_addr = target;
     65 	daemon_addr.sin_port = daemon_port;
     66 	ctl_mask = 1 << ctl_sockt;
     67 
     68 	/*
     69 	 * Keep sending the message until a response of
     70 	 * the proper type is obtained.
     71 	 */
     72 	do {
     73 		wait.tv_sec = CTL_WAIT;
     74 		wait.tv_usec = 0;
     75 		/* resend message until a response is obtained */
     76 		do {
     77 			cc = sendto(ctl_sockt, (char *)&msg, sizeof (msg), 0,
     78 			    (struct sockaddr *)&daemon_addr,
     79 			    sizeof (daemon_addr));
     80 			if (cc != sizeof (msg)) {
     81 				if (errno == EINTR)
     82 					continue;
     83 				p_error("Error on write to talk daemon");
     84 			}
     85 			read_mask = ctl_mask;
     86 			nready = select(32, &read_mask, 0, 0, &wait);
     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 			read_mask = ctl_mask;
    106 			/* an immediate poll */
    107 			timerclear(&wait);
    108 			nready = select(32, &read_mask, 0, 0, &wait);
    109 		} while (nready > 0 && (rp->vers != TALK_VERSION ||
    110 		    rp->type != type));
    111 	} while (rp->vers != TALK_VERSION || rp->type != type);
    112 	rp->id_num = ntohl(rp->id_num);
    113 	rp->addr.sa_family = ntohs(rp->addr.sa_family);
    114 }
    115