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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #ifndef lint
  31 #if 0
  32 static char sccsid[] = "@(#)process.c   8.2 (Berkeley) 11/16/93";
  33 #endif
  34 static const char rcsid[] =
  35   "$FreeBSD$";
  36 #endif /* not lint */
  37
  38 /*
  39  * process.c handles the requests, which can be of three types:
  40  *      ANNOUNCE - announce to a user that a talk is wanted
  41  *      LEAVE_INVITE - insert the request into the table
  42  *      LOOK_UP - look up to see if a request is waiting in
  43  *                in the table for the local user
  44  *      DELETE - delete invitation
  45  */
  46 #include <sys/param.h>
  47 #include <sys/stat.h>
  48 #include <sys/socket.h>
  49 #include <netinet/in.h>
  50 #include <protocols/talkd.h>
  51 #include <ctype.h>
  52 #include <err.h>
  53 #include <netdb.h>
  54 #include <paths.h>
  55 #include <stdio.h>
  56 #include <string.h>
  57 #include <syslog.h>
  58 #include <utmpx.h>
  59
  60 #include "extern.h"
  61
  62 void
  63 process_request(CTL_MSG *mp, CTL_RESPONSE *rp)
  64 {
  65         CTL_MSG *ptr;
  66         char *s;
  67
  68         rp->vers = TALK_VERSION;
  69         rp->type = mp->type;
  70         rp->id_num = htonl(0);
  71         if (mp->vers != TALK_VERSION) {
  72                 syslog(LOG_WARNING, "bad protocol version %d", mp->vers);
  73                 rp->answer = BADVERSION;
  74                 return;
  75         }
  76         mp->id_num = ntohl(mp->id_num);
  77         mp->addr.sa_family = ntohs(mp->addr.sa_family);
  78         if (mp->addr.sa_family != AF_INET) {
  79                 syslog(LOG_WARNING, "bad address, family %d",
  80                     mp->addr.sa_family);
  81                 rp->answer = BADADDR;
  82                 return;
  83         }
  84         mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
  85         if (mp->ctl_addr.sa_family != AF_INET) {
  86                 syslog(LOG_WARNING, "bad control address, family %d",
  87                     mp->ctl_addr.sa_family);
  88                 rp->answer = BADCTLADDR;
  89                 return;
  90         }
  91         for (s = mp->l_name; *s; s++)
  92                 if (!isprint(*s)) {
  93                         syslog(LOG_NOTICE, "illegal user name. Aborting");
  94                         rp->answer = FAILED;
  95                         return;
  96                 }
  97         mp->pid = ntohl(mp->pid);
  98         if (debug)
  99                 print_request("process_request", mp);
 100         switch (mp->type) {
 101
 102         case ANNOUNCE:
 103                 do_announce(mp, rp);
 104                 break;
 105
 106         case LEAVE_INVITE:
 107                 ptr = find_request(mp);
 108                 if (ptr != (CTL_MSG *)0) {
 109                         rp->id_num = htonl(ptr->id_num);
 110                         rp->answer = SUCCESS;
 111                 } else
 112                         insert_table(mp, rp);
 113                 break;
 114
 115         case LOOK_UP:
 116                 ptr = find_match(mp);
 117                 if (ptr != (CTL_MSG *)0) {
 118                         rp->id_num = htonl(ptr->id_num);
 119                         rp->addr = ptr->addr;
 120                         rp->addr.sa_family = htons(ptr->addr.sa_family);
 121                         rp->answer = SUCCESS;
 122                 } else
 123                         rp->answer = NOT_HERE;
 124                 break;
 125
 126         case DELETE:
 127                 rp->answer = delete_invite(mp->id_num);
 128                 break;
 129
 130         default:
 131                 rp->answer = UNKNOWN_REQUEST;
 132                 break;
 133         }
 134         if (debug)
 135                 print_response("process_request", rp);
 136 }
 137
 138 void
 139 do_announce(CTL_MSG *mp, CTL_RESPONSE *rp)
 140 {
 141         struct hostent *hp;
 142         CTL_MSG *ptr;
 143         int result;
 144
 145         /* see if the user is logged */
 146         result = find_user(mp->r_name, mp->r_tty);
 147         if (result != SUCCESS) {
 148                 rp->answer = result;
 149                 return;
 150         }
 151 #define satosin(sa)     ((struct sockaddr_in *)(void *)(sa))
 152         hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr,
 153                 sizeof (struct in_addr), AF_INET);
 154         if (hp == (struct hostent *)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, hp->h_name);
 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, hp->h_name);
 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)
 184 {
 185         struct utmpx *ut;
 186         int status;
 187         struct stat statb;
 188         time_t best = 0;
 189         char ftty[sizeof(_PATH_DEV) - 1 + sizeof(ut->ut_line)];
 190
 191         setutxent();
 192         status = NOT_HERE;
 193         (void) strcpy(ftty, _PATH_DEV);
 194         while ((ut = getutxent()) != NULL)
 195                 if (ut->ut_type == USER_PROCESS &&
 196                     strcmp(ut->ut_user, name) == 0) {
 197                         if (*tty == '\0' || best != 0) {
 198                                 if (best == 0)
 199                                         status = PERMISSION_DENIED;
 200                                 /* no particular tty was requested */
 201                                 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1,
 202                                     ut->ut_line);
 203                                 if (stat(ftty, &statb) == 0) {
 204                                         if (!(statb.st_mode & 020))
 205                                                 continue;
 206                                         if (statb.st_atime > best) {
 207                                                 best = statb.st_atime;
 208                                                 (void) strcpy(tty, ut->ut_line);
 209                                                 status = SUCCESS;
 210                                                 continue;
 211                                         }
 212                                 }
 213                         }
 214                         if (strcmp(ut->ut_line, tty) == 0) {
 215                                 status = SUCCESS;
 216                                 break;
 217                         }
 218                 }
 219         endutxent();
 220         return (status);
 221 }