usr.bin/talk/ctl_transact.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)ctl_transact.c   8.1 (Berkeley) 6/6/93
  30  * $FreeBSD: src/usr.bin/talk/ctl_transact.c,v 1.5 1999/08/28 01:06:11 peter Exp $
  31  */
  32
  33 #include <errno.h>
  34 #include <string.h>
  35 #include "talk.h"
  36 #include "talk_ctl.h"
  37
  38 #define CTL_WAIT 2      /* time to wait for a response, in seconds */
  39
  40 /*
  41  * SOCKDGRAM is unreliable, so we must repeat messages if we have
  42  * not recieved an acknowledgement within a reasonable amount
  43  * of time
  44  */
  45 void
  46 ctl_transact(struct in_addr target, CTL_MSG lmsg, int type, CTL_RESPONSE *rp)
  47 {
  48         fd_set read_mask, ctl_mask;
  49         int nready = 0, cc;
  50         struct timeval wait;
  51
  52         lmsg.type = type;
  53         daemon_addr.sin_addr = target;
  54         daemon_addr.sin_port = daemon_port;
  55         FD_ZERO(&ctl_mask);
  56         FD_SET(ctl_sockt, &ctl_mask);
  57
  58         /*
  59          * Keep sending the message until a response of
  60          * the proper type is obtained.
  61          */
  62         do {
  63                 wait.tv_sec = CTL_WAIT;
  64                 wait.tv_usec = 0;
  65                 /* resend message until a response is obtained */
  66                 do {
  67                         cc = sendto(ctl_sockt, (char *)&lmsg, sizeof (lmsg), 0,
  68                             (struct sockaddr *)&daemon_addr,
  69                             sizeof (daemon_addr));
  70                         if (cc != sizeof (lmsg)) {
  71                                 if (errno == EINTR)
  72                                         continue;
  73                                 p_error("Error on write to talk daemon");
  74                         }
  75                         read_mask = ctl_mask;
  76                         nready = select(32, &read_mask, 0, 0, &wait);
  77                         if (nready < 0) {
  78                                 if (errno == EINTR)
  79                                         continue;
  80                                 p_error("Error waiting for daemon response");
  81                         }
  82                 } while (nready == 0);
  83                 /*
  84                  * Keep reading while there are queued messages
  85                  * (this is not necessary, it just saves extra
  86                  * request/acknowledgements being sent)
  87                  */
  88                 do {
  89                         cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
  90                         if (cc < 0) {
  91                                 if (errno == EINTR)
  92                                         continue;
  93                                 p_error("Error on read from talk daemon");
  94                         }
  95                         read_mask = ctl_mask;
  96                         /* an immediate poll */
  97                         timerclear(&wait);
  98                         nready = select(32, &read_mask, 0, 0, &wait);
  99                 } while (nready > 0 && (rp->vers != TALK_VERSION ||
 100                     rp->type != type));
 101         } while (rp->vers != TALK_VERSION || rp->type != type);
 102         rp->id_num = ntohl(rp->id_num);
 103         rp->addr.sa_family = ntohs(rp->addr.sa_family);
 104 }