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  * 4. 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
  30 #include <sys/cdefs.h>
  31
  32 __FBSDID("$FreeBSD$");
  33
  34 #ifndef lint
  35 static const char sccsid[] = "@(#)ctl_transact.c        8.1 (Berkeley) 6/6/93";
  36 #endif
  37
  38 #include <arpa/inet.h>
  39
  40 #include <errno.h>
  41 #include <poll.h>
  42
  43 #include "talk.h"
  44 #include "talk_ctl.h"
  45
  46 #define CTL_WAIT 2      /* time to wait for a response, in seconds */
  47
  48 /*
  49  * SOCKDGRAM is unreliable, so we must repeat messages if we have
  50  * not received an acknowledgement within a reasonable amount
  51  * of time
  52  */
  53 void
  54 ctl_transact(struct in_addr target, CTL_MSG lmsg, int type, CTL_RESPONSE *rp)
  55 {
  56         struct pollfd pfd[1];
  57         int nready = 0, cc;
  58
  59         lmsg.type = type;
  60         daemon_addr.sin_addr = target;
  61         daemon_addr.sin_port = daemon_port;
  62         pfd[0].fd = ctl_sockt;
  63         pfd[0].events = POLLIN;
  64
  65         /*
  66          * Keep sending the message until a response of
  67          * the proper type is obtained.
  68          */
  69         do {
  70                 /* resend message until a response is obtained */
  71                 do {
  72                         cc = sendto(ctl_sockt, (char *)&lmsg, sizeof (lmsg), 0,
  73                             (struct sockaddr *)&daemon_addr,
  74                             sizeof (daemon_addr));
  75                         if (cc != sizeof (lmsg)) {
  76                                 if (errno == EINTR)
  77                                         continue;
  78                                 p_error("Error on write to talk daemon");
  79                         }
  80                         nready = poll(pfd, 1, CTL_WAIT * 1000);
  81                         if (nready < 0) {
  82                                 if (errno == EINTR)
  83                                         continue;
  84                                 p_error("Error waiting for daemon response");
  85                         }
  86                 } while (nready == 0);
  87                 /*
  88                  * Keep reading while there are queued messages
  89                  * (this is not necessary, it just saves extra
  90                  * request/acknowledgements being sent)
  91                  */
  92                 do {
  93                         cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
  94                         if (cc < 0) {
  95                                 if (errno == EINTR)
  96                                         continue;
  97                                 p_error("Error on read from talk daemon");
  98                         }
  99                         nready = poll(pfd, 1, 0);
 100                 } while (nready > 0 && (rp->vers != TALK_VERSION ||
 101                     rp->type != type));
 102         } while (rp->vers != TALK_VERSION || rp->type != type);
 103         rp->id_num = ntohl(rp->id_num);
 104         rp->addr.sa_family = ntohs(rp->addr.sa_family);
 105 }