libexec/talkd/process.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  * @(#)process.c        8.2 (Berkeley) 11/16/93
  34  * $FreeBSD: src/libexec/talkd/process.c,v 1.9 1999/08/28 00:10:16 peter Exp $
  35  */
  36
  37 /*
  38  * process.c handles the requests, which can be of three types:
  39  *      ANNOUNCE - announce to a user that a talk is wanted
  40  *      LEAVE_INVITE - insert the request into the table
  41  *      LOOK_UP - look up to see if a request is waiting in
  42  *                in the table for the local user
  43  *      DELETE - delete invitation
  44  */
  45 #include <sys/param.h>
  46 #include <sys/stat.h>
  47 #include <sys/socket.h>
  48 #include <netinet/in.h>
  49 #include <protocols/talkd.h>
  50 #include <ctype.h>
  51 #include <err.h>
  52 #include <netdb.h>
  53 #include <paths.h>
  54 #include <stdio.h>
  55 #include <string.h>
  56 #include <syslog.h>
  57 #include "utmpentry.h"
  58
  59 #include "extern.h"
  60
  61 extern int debug;
  62
  63 void
  64 process_request(CTL_MSG *mp, CTL_RESPONSE *rp)
  65 {
  66         CTL_MSG *ptr;
  67         char *s;
  68
  69         rp->vers = TALK_VERSION;
  70         rp->type = mp->type;
  71         rp->id_num = htonl(0);
  72         if (mp->vers != TALK_VERSION) {
  73                 syslog(LOG_WARNING, "bad protocol version %d", mp->vers);
  74                 rp->answer = BADVERSION;
  75                 return;
  76         }
  77         mp->id_num = ntohl(mp->id_num);
  78         mp->addr.sa_family = ntohs(mp->addr.sa_family);
  79         if (mp->addr.sa_family != AF_INET) {
  80                 syslog(LOG_WARNING, "bad address, family %d",
  81                     mp->addr.sa_family);
  82                 rp->answer = BADADDR;
  83                 return;
  84         }
  85         mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
  86         if (mp->ctl_addr.sa_family != AF_INET) {
  87                 syslog(LOG_WARNING, "bad control address, family %d",
  88                     mp->ctl_addr.sa_family);
  89                 rp->answer = BADCTLADDR;
  90                 return;
  91         }
  92         for (s = mp->l_name; *s; s++)
  93                 if (!isprint(*s)) {
  94                         syslog(LOG_NOTICE, "illegal user name. Aborting");
  95                         rp->answer = FAILED;
  96                         return;
  97                 }
  98         mp->pid = ntohl(mp->pid);
  99         if (debug)
 100                 print_request("process_request", mp);
 101         switch (mp->type) {
 102
 103         case ANNOUNCE:
 104                 do_announce(mp, rp);
 105                 break;
 106
 107         case LEAVE_INVITE:
 108                 ptr = find_request(mp);
 109                 if (ptr != NULL) {
 110                         rp->id_num = htonl(ptr->id_num);
 111                         rp->answer = SUCCESS;
 112                 } else
 113                         insert_table(mp, rp);
 114                 break;
 115
 116         case LOOK_UP:
 117                 ptr = find_match(mp);
 118                 if (ptr != NULL) {
 119                         rp->id_num = htonl(ptr->id_num);
 120                         rp->addr = ptr->addr;
 121                         rp->addr.sa_family = htons(ptr->addr.sa_family);
 122                         rp->answer = SUCCESS;
 123                 } else
 124                         rp->answer = NOT_HERE;
 125                 break;
 126
 127         case DELETE:
 128                 rp->answer = delete_invite(mp->id_num);
 129                 break;
 130
 131         default:
 132                 rp->answer = UNKNOWN_REQUEST;
 133                 break;
 134         }
 135         if (debug)
 136                 print_response("process_request", rp);
 137 }
 138
 139 void
 140 do_announce(CTL_MSG *mp, CTL_RESPONSE *rp)
 141 {
 142         struct hostent *hp;
 143         CTL_MSG *ptr;
 144         int result;
 145
 146         /* see if the user is logged */
 147         result = find_user(mp->r_name, mp->r_tty);
 148         if (result != SUCCESS) {
 149                 rp->answer = result;
 150                 return;
 151         }
 152 #define satosin(sa)     ((struct sockaddr_in *)(void *)(sa))
 153         hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr,
 154                 sizeof (struct in_addr), AF_INET);
 155         if (hp == NULL) {
 156                 rp->answer = MACHINE_UNKNOWN;
 157                 return;
 158         }
 159         ptr = find_request(mp);
 160         if (ptr == NULL) {
 161                 insert_table(mp, rp);
 162                 rp->answer = announce(mp, hp->h_name);
 163                 return;
 164         }
 165         if (mp->id_num > ptr->id_num) {
 166                 /*
 167                  * This is an explicit re-announce, so update the id_num
 168                  * field to avoid duplicates and re-announce the talk.
 169                  */
 170                 ptr->id_num = new_id();
 171                 rp->id_num = htonl(ptr->id_num);
 172                 rp->answer = announce(mp, hp->h_name);
 173         } else {
 174                 /* a duplicated request, so ignore it */
 175                 rp->id_num = htonl(ptr->id_num);
 176                 rp->answer = SUCCESS;
 177         }
 178 }
 179
 180 /*
 181  * Search utmp for the local user
 182  */
 183 int
 184 find_user(const char *name, char *tty)
 185 {
 186         struct utmpentry *ep;
 187         int status;
 188         struct stat statb;
 189         time_t best = 0;
 190         char ftty[sizeof(_PATH_DEV) + sizeof(ep->line)];
 191
 192         getutentries(NULL, &ep);
 193
 194 #define SCMPN(a, b)     strncmp(a, b, sizeof (a))
 195         status = NOT_HERE;
 196         (void) strcpy(ftty, _PATH_DEV);
 197         for (; ep; ep = ep->next)
 198                 if (SCMPN(ep->name, name) == 0) {
 199                         if (*tty == '\0' || best != 0) {
 200                                 if (best == 0)
 201                                         status = PERMISSION_DENIED;
 202                                 /* no particular tty was requested */
 203                                 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1,
 204                                     ep->line);
 205                                 if (stat(ftty, &statb) == 0) {
 206                                         if (!(statb.st_mode & 020))
 207                                                 continue;
 208                                         if (statb.st_atime > best) {
 209                                                 best = statb.st_atime;
 210                                                 (void) strcpy(tty, ep->line);
 211                                                 status = SUCCESS;
 212                                                 continue;
 213                                         }
 214                                 }
 215                         }
 216                         if (strcmp(ep->line, tty) == 0) {
 217                                 status = SUCCESS;
 218                                 break;
 219                         }
 220                 }
 221
 222         return (status);
 223 }