usr.bin/talk/ctl_transact.c

   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, tmsg, type, rp)
  56         struct in_addr target;
  57         CTL_MSG tmsg;
  58         int type;
  59         CTL_RESPONSE *rp;
  60 {
  61         struct pollfd set[1];
  62         int nready, cc;
  63
  64         nready = 0;
  65         tmsg.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 *)&tmsg, sizeof (tmsg), 0,
  79                             (struct sockaddr *)&daemon_addr,
  80                             sizeof (daemon_addr));
  81                         if (cc != sizeof (tmsg)) {
  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 }