libexec/talkd/process.c

   1 /*      $NetBSD: process.c,v 1.13 2009/03/16 01:04:32 lukem 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[] = "@(#)process.c   8.2 (Berkeley) 11/16/93";
  36 #else
  37 __RCSID("$NetBSD: process.c,v 1.13 2009/03/16 01:04:32 lukem Exp $");
  38 #endif
  39 #endif /* not lint */
  40
  41 /*
  42  * process.c handles the requests, which can be of three types:
  43  *      ANNOUNCE - announce to a user that a talk is wanted
  44  *      LEAVE_INVITE - insert the request into the table
  45  *      LOOK_UP - look up to see if a request is waiting in
  46  *                in the table for the local user
  47  *      DELETE - delete invitation
  48  */
  49
  50 #include <sys/param.h>
  51 #include <sys/stat.h>
  52 #include <sys/socket.h>
  53
  54 #include <netinet/in.h>
  55
  56 #include <protocols/talkd.h>
  57
  58 #include <netdb.h>
  59 #include <syslog.h>
  60 #include <stdio.h>
  61 #include <string.h>
  62 #include <paths.h>
  63
  64 #include "extern.h"
  65
  66 #include "utmpentry.h"
  67
  68 void
  69 process_request(CTL_MSG *mp, CTL_RESPONSE *rp)
  70 {
  71         CTL_MSG *ptr;
  72
  73         rp->vers = TALK_VERSION;
  74         rp->type = mp->type;
  75         rp->id_num = htonl(0);
  76         mp->id_num = ntohl(mp->id_num);
  77         mp->addr.sa_family = ntohs(mp->addr.sa_family);
  78         mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
  79         mp->pid = ntohl(mp->pid);
  80         if (mp->vers != TALK_VERSION) {
  81                 syslog(LOG_WARNING, "Bad protocol version %d", mp->vers);
  82                 rp->answer = BADVERSION;
  83                 return;
  84         }
  85         if (mp->addr.sa_family != AF_INET) {
  86                 syslog(LOG_WARNING, "Bad address, family %d",
  87                     mp->addr.sa_family);
  88                 rp->answer = BADADDR;
  89                 return;
  90         }
  91         if (mp->ctl_addr.sa_family != AF_INET) {
  92                 syslog(LOG_WARNING, "Bad control address, family %d",
  93                     mp->ctl_addr.sa_family);
  94                 rp->answer = BADCTLADDR;
  95                 return;
  96         }
  97         if (debug || logging)
  98                 print_request("request", mp);
  99         switch (mp->type) {
 100
 101         case ANNOUNCE:
 102                 do_announce(mp, rp);
 103                 break;
 104
 105         case LEAVE_INVITE:
 106                 ptr = find_request(mp);
 107                 if (ptr != (CTL_MSG *)0) {
 108                         rp->id_num = htonl(ptr->id_num);
 109                         rp->answer = SUCCESS;
 110                 } else
 111                         insert_table(mp, rp);
 112                 break;
 113
 114         case LOOK_UP:
 115                 ptr = find_match(mp);
 116                 if (ptr != (CTL_MSG *)0) {
 117                         rp->id_num = htonl(ptr->id_num);
 118                         rp->addr = ptr->addr;
 119                         rp->addr.sa_family = htons(ptr->addr.sa_family);
 120                         rp->answer = SUCCESS;
 121                 } else
 122                         rp->answer = NOT_HERE;
 123                 break;
 124
 125         case DELETE:
 126                 rp->answer = delete_invite(mp->id_num);
 127                 break;
 128
 129         default:
 130                 rp->answer = UNKNOWN_REQUEST;
 131                 break;
 132         }
 133         if (debug)
 134                 print_response("process_request done", rp);
 135 }
 136
 137 void
 138 do_announce(CTL_MSG *mp, CTL_RESPONSE *rp)
 139 {
 140         CTL_MSG *ptr;
 141         int result;
 142         char hostname[NI_MAXHOST];
 143         struct sockaddr sa;
 144
 145         tsa2sa(&sa, &mp->ctl_addr);
 146
 147         /* see if the user is logged */
 148         result = find_user(mp->r_name, mp->r_tty, sizeof(mp->r_tty));
 149         if (result != SUCCESS) {
 150                 rp->answer = result;
 151                 return;
 152         }
 153         if (getnameinfo(&sa, sa.sa_len, hostname, sizeof(hostname), NULL,
 154             0, 0)) {
 155                 rp->answer = MACHINE_UNKNOWN;
 156                 return;
 157         }
 158         ptr = find_request(mp);
 159         if (ptr == (CTL_MSG *) 0) {
 160                 insert_table(mp, rp);
 161                 rp->answer = announce(mp, hostname);
 162                 return;
 163         }
 164         if (mp->id_num > ptr->id_num) {
 165                 /*
 166                  * This is an explicit re-announce, so update the id_num
 167                  * field to avoid duplicates and re-announce the talk.
 168                  */
 169                 ptr->id_num = new_id();
 170                 rp->id_num = htonl(ptr->id_num);
 171                 rp->answer = announce(mp, hostname);
 172         } else {
 173                 /* a duplicated request, so ignore it */
 174                 rp->id_num = htonl(ptr->id_num);
 175                 rp->answer = SUCCESS;
 176         }
 177 }
 178
 179 /*
 180  * Search utmp for the local user
 181  */
 182 int
 183 find_user(const char *name, char *tty, size_t ttysize)
 184 {
 185         int status;
 186         struct stat statb;
 187         struct utmpentry *ep;
 188         char ftty[sizeof(_PATH_DEV) + sizeof(ep->line)];
 189         time_t atime = 0;
 190         int anytty = 0;
 191
 192         (void)getutentries(NULL, &ep);
 193
 194         status = NOT_HERE;
 195         (void) strlcpy(ftty, _PATH_DEV, sizeof(ftty));
 196
 197         if (*tty == '\0')
 198                 anytty = 1;
 199
 200         for (; ep; ep = ep->next) {
 201                 if (strcmp(ep->name, name) != 0)
 202                         continue;
 203                 if (anytty) {
 204                         /* no particular tty was requested */
 205                         (void)strlcpy(ftty + sizeof(_PATH_DEV) - 1, ep->line,
 206                              sizeof(ftty) - sizeof(_PATH_DEV) + 1);
 207                         if (stat(ftty, &statb) != 0)
 208                                 continue;
 209
 210                         if (!(statb.st_mode & S_IWGRP)) {
 211                                 if (status != SUCCESS)
 212                                         status = PERMISSION_DENIED;
 213                                 continue;
 214                         }
 215                         if (statb.st_atime > atime &&
 216                             strlcpy(tty, ep->line, ttysize) < ttysize) {
 217                                 atime = statb.st_atime;
 218                                 status = SUCCESS;
 219                         }
 220                 } else if (strcmp(ep->line, tty) == 0) {
 221                         status = SUCCESS;
 222                         break;
 223                 }
 224         }
 225         return (status);
 226 }