remote_cmds/talk.tproj/look_up.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
  34 #include <sys/cdefs.h>
  35
  36 #ifndef __APPLE__
  37 __FBSDID("$FreeBSD: src/usr.bin/talk/look_up.c,v 1.8 2005/02/09 09:13:36 stefanf Exp $");
  38
  39 #ifndef lint
  40 static const char sccsid[] = "@(#)look_up.c     8.1 (Berkeley) 6/6/93";
  41 #endif
  42 #endif /* __APPLE__ */
  43
  44 #include <sys/types.h>
  45 #include <sys/socket.h>
  46 #include <protocols/talkd.h>
  47
  48 #include <errno.h>
  49 #include <string.h>
  50
  51 #include "talk_ctl.h"
  52 #include "talk.h"
  53
  54 /*
  55  * See if the local daemon has an invitation for us.
  56  */
  57 int
  58 check_local()
  59 {
  60         CTL_RESPONSE response;
  61         CTL_RESPONSE *rp = &response;
  62         struct sockaddr addr;
  63
  64         /* the rest of msg was set up in get_names */
  65 #ifdef MSG_EOR
  66         /* copy new style sockaddr to old, swap family (short in old) */
  67         msg.ctl_addr = *(struct osockaddr *)&ctl_addr;
  68         msg.ctl_addr.sa_family = htons(ctl_addr.sin_family);
  69 #else
  70         msg.ctl_addr = *(struct sockaddr *)&ctl_addr;
  71 #endif
  72         /* must be initiating a talk */
  73         if (!look_for_invite(rp))
  74                 return (0);
  75         /*
  76          * There was an invitation waiting for us,
  77          * so connect with the other (hopefully waiting) party
  78          */
  79         current_state = "Waiting to connect with caller";
  80         do {
  81                 if (rp->addr.sa_family != AF_INET)
  82                         p_error("Response uses invalid network address");
  83                 (void)memcpy(&addr, &rp->addr.sa_family, sizeof(addr));
  84                 addr.sa_family = rp->addr.sa_family;
  85                 addr.sa_len = sizeof(addr);
  86                 errno = 0;
  87                 if (connect(sockt, &addr, sizeof(addr)) != -1)
  88                         return (1);
  89         } while (errno == EINTR);
  90         if (errno == ECONNREFUSED) {
  91                 /*
  92                  * The caller gave up, but his invitation somehow
  93                  * was not cleared. Clear it and initiate an
  94                  * invitation. (We know there are no newer invitations,
  95                  * the talkd works LIFO.)
  96                  */
  97                 ctl_transact(his_machine_addr, msg, DELETE, rp);
  98                 close(sockt);
  99                 open_sockt();
 100                 return (0);
 101         }
 102         p_error("Unable to connect with initiator");
 103         /*NOTREACHED*/
 104         return (0);
 105 }
 106
 107 /*
 108  * Look for an invitation on 'machine'
 109  */
 110 int
 111 look_for_invite(rp)
 112         CTL_RESPONSE *rp;
 113 {
 114         current_state = "Checking for invitation on caller's machine";
 115         ctl_transact(his_machine_addr, msg, LOOK_UP, rp);
 116         /* the switch is for later options, such as multiple invitations */
 117         switch (rp->answer) {
 118
 119         case SUCCESS:
 120                 msg.id_num = htonl(rp->id_num);
 121                 return (1);
 122
 123         default:
 124                 /* there wasn't an invitation waiting for us */
 125                 return (0);
 126         }
 127 }