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. 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  * @(#)ctl_transact.c   8.1 (Berkeley) 6/6/93
  34  * $FreeBSD: src/usr.bin/talk/ctl_transact.c,v 1.5 1999/08/28 01:06:11 peter Exp $
  35  * $DragonFly: src/usr.bin/talk/ctl_transact.c,v 1.3 2003/10/04 20:36:52 hmp Exp $
  36  */
  37
  38 #include <errno.h>
  39 #include <string.h>
  40 #include "talk.h"
  41 #include "talk_ctl.h"
  42
  43 #define CTL_WAIT 2      /* time to wait for a response, in seconds */
  44
  45 /*
  46  * SOCKDGRAM is unreliable, so we must repeat messages if we have
  47  * not recieved an acknowledgement within a reasonable amount
  48  * of time
  49  */
  50 void
  51 ctl_transact(struct in_addr target, CTL_MSG msg, int type, CTL_RESPONSE *rp)
  52 {
  53         fd_set read_mask, ctl_mask;
  54         int nready = 0, cc;
  55         struct timeval wait;
  56
  57         msg.type = type;
  58         daemon_addr.sin_addr = target;
  59         daemon_addr.sin_port = daemon_port;
  60         FD_ZERO(&ctl_mask);
  61         FD_SET(ctl_sockt, &ctl_mask);
  62
  63         /*
  64          * Keep sending the message until a response of
  65          * the proper type is obtained.
  66          */
  67         do {
  68                 wait.tv_sec = CTL_WAIT;
  69                 wait.tv_usec = 0;
  70                 /* resend message until a response is obtained */
  71                 do {
  72                         cc = sendto(ctl_sockt, (char *)&msg, sizeof (msg), 0,
  73                             (struct sockaddr *)&daemon_addr,
  74                             sizeof (daemon_addr));
  75                         if (cc != sizeof (msg)) {
  76                                 if (errno == EINTR)
  77                                         continue;
  78                                 p_error("Error on write to talk daemon");
  79                         }
  80                         read_mask = ctl_mask;
  81                         nready = select(32, &read_mask, 0, 0, &wait);
  82                         if (nready < 0) {
  83                                 if (errno == EINTR)
  84                                         continue;
  85                                 p_error("Error waiting for daemon response");
  86                         }
  87                 } while (nready == 0);
  88                 /*
  89                  * Keep reading while there are queued messages
  90                  * (this is not necessary, it just saves extra
  91                  * request/acknowledgements being sent)
  92                  */
  93                 do {
  94                         cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
  95                         if (cc < 0) {
  96                                 if (errno == EINTR)
  97                                         continue;
  98                                 p_error("Error on read from talk daemon");
  99                         }
 100                         read_mask = ctl_mask;
 101                         /* an immediate poll */
 102                         timerclear(&wait);
 103                         nready = select(32, &read_mask, 0, 0, &wait);
 104                 } while (nready > 0 && (rp->vers != TALK_VERSION ||
 105                     rp->type != type));
 106         } while (rp->vers != TALK_VERSION || rp->type != type);
 107         rp->id_num = ntohl(rp->id_num);
 108         rp->addr.sa_family = ntohs(rp->addr.sa_family);
 109 }