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  * @(#)process.c        8.2 (Berkeley) 11/16/93
  30  * $FreeBSD: src/libexec/talkd/process.c,v 1.9 1999/08/28 00:10:16 peter Exp $
  31  */
  32
  33 /*
  34  * process.c handles the requests, which can be of three types:
  35  *      ANNOUNCE - announce to a user that a talk is wanted
  36  *      LEAVE_INVITE - insert the request into the table
  37  *      LOOK_UP - look up to see if a request is waiting in
  38  *                in the table for the local user
  39  *      DELETE - delete invitation
  40  */
  41 #include <sys/param.h>
  42 #include <sys/stat.h>
  43 #include <sys/socket.h>
  44 #include <netinet/in.h>
  45 #include <protocols/talkd.h>
  46 #include <ctype.h>
  47 #include <err.h>
  48 #include <netdb.h>
  49 #include <paths.h>
  50 #include <stdio.h>
  51 #include <string.h>
  52 #include <syslog.h>
  53 #include "utmpentry.h"
  54
  55 #include "extern.h"
  56
  57 extern int debug;
  58
  59 void
  60 process_request(CTL_MSG *mp, CTL_RESPONSE *rp)
  61 {
  62         CTL_MSG *ptr;
  63         char *s;
  64
  65         rp->vers = TALK_VERSION;
  66         rp->type = mp->type;
  67         rp->id_num = htonl(0);
  68         if (mp->vers != TALK_VERSION) {
  69                 syslog(LOG_WARNING, "bad protocol version %d", mp->vers);
  70                 rp->answer = BADVERSION;
  71                 return;
  72         }
  73         mp->id_num = ntohl(mp->id_num);
  74         mp->addr.sa_family = ntohs(mp->addr.sa_family);
  75         if (mp->addr.sa_family != AF_INET) {
  76                 syslog(LOG_WARNING, "bad address, family %d",
  77                     mp->addr.sa_family);
  78                 rp->answer = BADADDR;
  79                 return;
  80         }
  81         mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
  82         if (mp->ctl_addr.sa_family != AF_INET) {
  83                 syslog(LOG_WARNING, "bad control address, family %d",
  84                     mp->ctl_addr.sa_family);
  85                 rp->answer = BADCTLADDR;
  86                 return;
  87         }
  88         for (s = mp->l_name; *s; s++)
  89                 if (!isprint(*s)) {
  90                         syslog(LOG_NOTICE, "illegal user name. Aborting");
  91                         rp->answer = FAILED;
  92                         return;
  93                 }
  94         mp->pid = ntohl(mp->pid);
  95         if (debug)
  96                 print_request("process_request", mp);
  97         switch (mp->type) {
  98
  99         case ANNOUNCE:
 100                 do_announce(mp, rp);
 101                 break;
 102
 103         case LEAVE_INVITE:
 104                 ptr = find_request(mp);
 105                 if (ptr != NULL) {
 106                         rp->id_num = htonl(ptr->id_num);
 107                         rp->answer = SUCCESS;
 108                 } else
 109                         insert_table(mp, rp);
 110                 break;
 111
 112         case LOOK_UP:
 113                 ptr = find_match(mp);
 114                 if (ptr != NULL) {
 115                         rp->id_num = htonl(ptr->id_num);
 116                         rp->addr = ptr->addr;
 117                         rp->addr.sa_family = htons(ptr->addr.sa_family);
 118                         rp->answer = SUCCESS;
 119                 } else
 120                         rp->answer = NOT_HERE;
 121                 break;
 122
 123         case DELETE:
 124                 rp->answer = delete_invite(mp->id_num);
 125                 break;
 126
 127         default:
 128                 rp->answer = UNKNOWN_REQUEST;
 129                 break;
 130         }
 131         if (debug)
 132                 print_response("process_request", rp);
 133 }
 134
 135 void
 136 do_announce(CTL_MSG *mp, CTL_RESPONSE *rp)
 137 {
 138         struct hostent *hp;
 139         CTL_MSG *ptr;
 140         int result;
 141
 142         /* see if the user is logged */
 143         result = find_user(mp->r_name, mp->r_tty);
 144         if (result != SUCCESS) {
 145                 rp->answer = result;
 146                 return;
 147         }
 148 #define satosin(sa)     ((struct sockaddr_in *)(void *)(sa))
 149         hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr,
 150                 sizeof (struct in_addr), AF_INET);
 151         if (hp == NULL) {
 152                 rp->answer = MACHINE_UNKNOWN;
 153                 return;
 154         }
 155         ptr = find_request(mp);
 156         if (ptr == NULL) {
 157                 insert_table(mp, rp);
 158                 rp->answer = announce(mp, hp->h_name);
 159                 return;
 160         }
 161         if (mp->id_num > ptr->id_num) {
 162                 /*
 163                  * This is an explicit re-announce, so update the id_num
 164                  * field to avoid duplicates and re-announce the talk.
 165                  */
 166                 ptr->id_num = new_id();
 167                 rp->id_num = htonl(ptr->id_num);
 168                 rp->answer = announce(mp, hp->h_name);
 169         } else {
 170                 /* a duplicated request, so ignore it */
 171                 rp->id_num = htonl(ptr->id_num);
 172                 rp->answer = SUCCESS;
 173         }
 174 }
 175
 176 /*
 177  * Search utmp for the local user
 178  */
 179 int
 180 find_user(const char *name, char *tty)
 181 {
 182         struct utmpentry *ep = NULL;    /* avoid gcc warnings */
 183         int status;
 184         struct stat statb;
 185         time_t best = 0;
 186         char ftty[sizeof(_PATH_DEV) + sizeof(ep->line)];
 187
 188         getutentries(NULL, &ep);
 189
 190 #define SCMPN(a, b)     strncmp(a, b, sizeof (a))
 191         status = NOT_HERE;
 192         (void) strcpy(ftty, _PATH_DEV);
 193         for (; ep; ep = ep->next)
 194                 if (SCMPN(ep->name, name) == 0) {
 195                         if (*tty == '\0' || best != 0) {
 196                                 if (best == 0)
 197                                         status = PERMISSION_DENIED;
 198                                 /* no particular tty was requested */
 199                                 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1,
 200                                     ep->line);
 201                                 if (stat(ftty, &statb) == 0) {
 202                                         if (!(statb.st_mode & 020))
 203                                                 continue;
 204                                         if (statb.st_atime > best) {
 205                                                 best = statb.st_atime;
 206                                                 (void) strcpy(tty, ep->line);
 207                                                 status = SUCCESS;
 208                                                 continue;
 209                                         }
 210                                 }
 211                         }
 212                         if (strcmp(ep->line, tty) == 0) {
 213                                 status = SUCCESS;
 214                                 break;
 215                         }
 216                 }
 217
 218         return (status);
 219 }