libexec/talkd/process.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   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 #ifndef lint
  33 #if 0
  34 static char sccsid[] = "@(#)process.c   8.2 (Berkeley) 11/16/93";
  35 #endif
  36 static const char rcsid[] =
  37   "$FreeBSD$";
  38 #endif /* not lint */
  39
  40 /*
  41  * process.c handles the requests, which can be of three types:
  42  *      ANNOUNCE - announce to a user that a talk is wanted
  43  *      LEAVE_INVITE - insert the request into the table
  44  *      LOOK_UP - look up to see if a request is waiting in
  45  *                in the table for the local user
  46  *      DELETE - delete invitation
  47  */
  48 #include <sys/param.h>
  49 #include <sys/stat.h>
  50 #include <sys/socket.h>
  51 #include <netinet/in.h>
  52 #include <protocols/talkd.h>
  53 #include <ctype.h>
  54 #include <err.h>
  55 #include <netdb.h>
  56 #include <paths.h>
  57 #include <stdio.h>
  58 #include <string.h>
  59 #include <syslog.h>
  60 #include <utmpx.h>
  61
  62 #include "extern.h"
  63
  64 void
  65 process_request(CTL_MSG *mp, CTL_RESPONSE *rp)
  66 {
  67         CTL_MSG *ptr;
  68         char *s;
  69
  70         rp->vers = TALK_VERSION;
  71         rp->type = mp->type;
  72         rp->id_num = htonl(0);
  73         if (mp->vers != TALK_VERSION) {
  74                 syslog(LOG_WARNING, "bad protocol version %d", mp->vers);
  75                 rp->answer = BADVERSION;
  76                 return;
  77         }
  78         mp->id_num = ntohl(mp->id_num);
  79         mp->addr.sa_family = ntohs(mp->addr.sa_family);
  80         if (mp->addr.sa_family != AF_INET) {
  81                 syslog(LOG_WARNING, "bad address, family %d",
  82                     mp->addr.sa_family);
  83                 rp->answer = BADADDR;
  84                 return;
  85         }
  86         mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
  87         if (mp->ctl_addr.sa_family != AF_INET) {
  88                 syslog(LOG_WARNING, "bad control address, family %d",
  89                     mp->ctl_addr.sa_family);
  90                 rp->answer = BADCTLADDR;
  91                 return;
  92         }
  93         for (s = mp->l_name; *s; s++)
  94                 if (!isprint(*s)) {
  95                         syslog(LOG_NOTICE, "illegal user name. Aborting");
  96                         rp->answer = FAILED;
  97                         return;
  98                 }
  99         mp->pid = ntohl(mp->pid);
 100         if (debug)
 101                 print_request("process_request", mp);
 102         switch (mp->type) {
 103
 104         case ANNOUNCE:
 105                 do_announce(mp, rp);
 106                 break;
 107
 108         case LEAVE_INVITE:
 109                 ptr = find_request(mp);
 110                 if (ptr != (CTL_MSG *)0) {
 111                         rp->id_num = htonl(ptr->id_num);
 112                         rp->answer = SUCCESS;
 113                 } else
 114                         insert_table(mp, rp);
 115                 break;
 116
 117         case LOOK_UP:
 118                 ptr = find_match(mp);
 119                 if (ptr != (CTL_MSG *)0) {
 120                         rp->id_num = htonl(ptr->id_num);
 121                         rp->addr = ptr->addr;
 122                         rp->addr.sa_family = htons(ptr->addr.sa_family);
 123                         rp->answer = SUCCESS;
 124                 } else
 125                         rp->answer = NOT_HERE;
 126                 break;
 127
 128         case DELETE:
 129                 rp->answer = delete_invite(mp->id_num);
 130                 break;
 131
 132         default:
 133                 rp->answer = UNKNOWN_REQUEST;
 134                 break;
 135         }
 136         if (debug)
 137                 print_response("process_request", rp);
 138 }
 139
 140 void
 141 do_announce(CTL_MSG *mp, CTL_RESPONSE *rp)
 142 {
 143         struct hostent *hp;
 144         CTL_MSG *ptr;
 145         int result;
 146
 147         /* see if the user is logged */
 148         result = find_user(mp->r_name, mp->r_tty);
 149         if (result != SUCCESS) {
 150                 rp->answer = result;
 151                 return;
 152         }
 153 #define satosin(sa)     ((struct sockaddr_in *)(void *)(sa))
 154         hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr,
 155                 sizeof (struct in_addr), AF_INET);
 156         if (hp == (struct hostent *)0) {
 157                 rp->answer = MACHINE_UNKNOWN;
 158                 return;
 159         }
 160         ptr = find_request(mp);
 161         if (ptr == (CTL_MSG *) 0) {
 162                 insert_table(mp, rp);
 163                 rp->answer = announce(mp, hp->h_name);
 164                 return;
 165         }
 166         if (mp->id_num > ptr->id_num) {
 167                 /*
 168                  * This is an explicit re-announce, so update the id_num
 169                  * field to avoid duplicates and re-announce the talk.
 170                  */
 171                 ptr->id_num = new_id();
 172                 rp->id_num = htonl(ptr->id_num);
 173                 rp->answer = announce(mp, hp->h_name);
 174         } else {
 175                 /* a duplicated request, so ignore it */
 176                 rp->id_num = htonl(ptr->id_num);
 177                 rp->answer = SUCCESS;
 178         }
 179 }
 180
 181 /*
 182  * Search utmp for the local user
 183  */
 184 int
 185 find_user(const char *name, char *tty)
 186 {
 187         struct utmpx *ut;
 188         int status;
 189         struct stat statb;
 190         time_t best = 0;
 191         char ftty[sizeof(_PATH_DEV) - 1 + sizeof(ut->ut_line)];
 192
 193         setutxent();
 194         status = NOT_HERE;
 195         (void) strcpy(ftty, _PATH_DEV);
 196         while ((ut = getutxent()) != NULL)
 197                 if (ut->ut_type == USER_PROCESS &&
 198                     strcmp(ut->ut_user, 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                                     ut->ut_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, ut->ut_line);
 211                                                 status = SUCCESS;
 212                                                 continue;
 213                                         }
 214                                 }
 215                         }
 216                         if (strcmp(ut->ut_line, tty) == 0) {
 217                                 status = SUCCESS;
 218                                 break;
 219                         }
 220                 }
 221         endutxent();
 222         return (status);
 223 }