usr.bin/talk/look_up.c

   1 /*      $NetBSD: look_up.c,v 1.6 2003/08/07 11:16:05 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[] = "@(#)look_up.c   8.1 (Berkeley) 6/6/93";
  36 #endif
  37 __RCSID("$NetBSD: look_up.c,v 1.6 2003/08/07 11:16:05 agc Exp $");
  38 #endif /* not lint */
  39
  40 #include "talk.h"
  41 #include <errno.h>
  42 #include <unistd.h>
  43 #include "talk_ctl.h"
  44
  45 /*
  46  * See if the local daemon has an invitation for us.
  47  */
  48 int
  49 check_local()
  50 {
  51         CTL_RESPONSE response;
  52         CTL_RESPONSE *rp = &response;
  53         struct sockaddr addr;
  54
  55         /* the rest of msg was set up in get_names */
  56 #ifdef MSG_EOR
  57         /* copy new style sockaddr to old, swap family (short in old) */
  58         msg.ctl_addr = *(struct talkd_sockaddr *)(void *)&ctl_addr;
  59         msg.ctl_addr.sa_family = htons(ctl_addr.sin_family);
  60 #else
  61         msg.ctl_addr = *(struct sockaddr *)&ctl_addr;
  62 #endif
  63         /* must be initiating a talk */
  64         if (!look_for_invite(rp))
  65                 return (0);
  66         /*
  67          * There was an invitation waiting for us,
  68          * so connect with the other (hopefully waiting) party
  69          */
  70         current_state = "Waiting to connect with caller";
  71         do {
  72                 if (rp->addr.sa_family != AF_INET)
  73                         p_error("Response uses invalid network address");
  74
  75                 (void)memcpy(&addr, &rp->addr.sa_family, sizeof(addr));
  76                 addr.sa_family = rp->addr.sa_family;
  77                 addr.sa_len = sizeof(addr);
  78
  79                 errno = 0;
  80                 if (connect(sockt, &addr, sizeof(addr)) != -1)
  81                         return (1);
  82         } while (errno == EINTR);
  83         if (errno == ECONNREFUSED) {
  84                 /*
  85                  * The caller gave up, but his invitation somehow
  86                  * was not cleared. Clear it and initiate an
  87                  * invitation. (We know there are no newer invitations,
  88                  * the talkd works LIFO.)
  89                  */
  90                 ctl_transact(his_machine_addr, msg, DELETE, rp);
  91                 close(sockt);
  92                 open_sockt();
  93                 return (0);
  94         }
  95         p_error("Unable to connect with initiator");
  96         /*NOTREACHED*/
  97         return (0);
  98 }
  99
 100 /*
 101  * Look for an invitation on 'machine'
 102  */
 103 int
 104 look_for_invite(rp)
 105         CTL_RESPONSE *rp;
 106 {
 107         current_state = "Checking for invitation on caller's machine";
 108         ctl_transact(his_machine_addr, msg, LOOK_UP, rp);
 109         /* the switch is for later options, such as multiple invitations */
 110         switch (rp->answer) {
 111
 112         case SUCCESS:
 113                 msg.id_num = htonl(rp->id_num);
 114                 return (1);
 115
 116         default:
 117                 /* there wasn't an invitation waiting for us */
 118                 return (0);
 119         }
 120 }