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
  34 #ifndef lint
  35 #if 0
  36 static char sccsid[] = "@(#)process.c   8.2 (Berkeley) 11/16/93";
  37 #endif
  38 static const char rcsid[] =
  39   "$FreeBSD$";
  40 #endif /* not lint */
  41
  42 /*
  43  * process.c handles the requests, which can be of three types:
  44  *      ANNOUNCE - announce to a user that a talk is wanted
  45  *      LEAVE_INVITE - insert the request into the table
  46  *      LOOK_UP - look up to see if a request is waiting in
  47  *                in the table for the local user
  48  *      DELETE - delete invitation
  49  */
  50 #include <sys/param.h>
  51 #include <sys/stat.h>
  52 #include <sys/socket.h>
  53 #include <netinet/in.h>
  54 #include <protocols/talkd.h>
  55 #include <ctype.h>
  56 #include <err.h>
  57 #include <netdb.h>
  58 #include <paths.h>
  59 #include <stdio.h>
  60 #include <string.h>
  61 #include <syslog.h>
  62
  63 #include "extern.h"
  64
  65 void
  66 process_request(CTL_MSG *mp, CTL_RESPONSE *rp)
  67 {
  68         CTL_MSG *ptr;
  69         extern int debug;
  70         char *s;
  71
  72         rp->vers = TALK_VERSION;
  73         rp->type = mp->type;
  74         rp->id_num = htonl(0);
  75         if (mp->vers != TALK_VERSION) {
  76                 syslog(LOG_WARNING, "bad protocol version %d", mp->vers);
  77                 rp->answer = BADVERSION;
  78                 return;
  79         }
  80         mp->id_num = ntohl(mp->id_num);
  81         mp->addr.sa_family = ntohs(mp->addr.sa_family);
  82         if (mp->addr.sa_family != AF_INET) {
  83                 syslog(LOG_WARNING, "bad address, family %d",
  84                     mp->addr.sa_family);
  85                 rp->answer = BADADDR;
  86                 return;
  87         }
  88         mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
  89         if (mp->ctl_addr.sa_family != AF_INET) {
  90                 syslog(LOG_WARNING, "bad control address, family %d",
  91                     mp->ctl_addr.sa_family);
  92                 rp->answer = BADCTLADDR;
  93                 return;
  94         }
  95         for (s = mp->l_name; *s; s++)
  96                 if (!isprint(*s)) {
  97                         syslog(LOG_NOTICE, "illegal user name. Aborting");
  98                         rp->answer = FAILED;
  99                         return;
 100                 }
 101         mp->pid = ntohl(mp->pid);
 102         if (debug)
 103                 print_request("process_request", mp);
 104         switch (mp->type) {
 105
 106         case ANNOUNCE:
 107                 do_announce(mp, rp);
 108                 break;
 109
 110         case LEAVE_INVITE:
 111                 ptr = find_request(mp);
 112                 if (ptr != (CTL_MSG *)0) {
 113                         rp->id_num = htonl(ptr->id_num);
 114                         rp->answer = SUCCESS;
 115                 } else
 116                         insert_table(mp, rp);
 117                 break;
 118
 119         case LOOK_UP:
 120                 ptr = find_match(mp);
 121                 if (ptr != (CTL_MSG *)0) {
 122                         rp->id_num = htonl(ptr->id_num);
 123                         rp->addr = ptr->addr;
 124                         rp->addr.sa_family = htons(ptr->addr.sa_family);
 125                         rp->answer = SUCCESS;
 126                 } else
 127                         rp->answer = NOT_HERE;
 128                 break;
 129
 130         case DELETE:
 131                 rp->answer = delete_invite(mp->id_num);
 132                 break;
 133
 134         default:
 135                 rp->answer = UNKNOWN_REQUEST;
 136                 break;
 137         }
 138         if (debug)
 139                 print_response("process_request", rp);
 140 }
 141
 142 void
 143 do_announce(CTL_MSG *mp, CTL_RESPONSE *rp)
 144 {
 145         struct hostent *hp;
 146         CTL_MSG *ptr;
 147         int result;
 148
 149         /* see if the user is logged */
 150         result = find_user(mp->r_name, mp->r_tty);
 151         if (result != SUCCESS) {
 152                 rp->answer = result;
 153                 return;
 154         }
 155 #define satosin(sa)     ((struct sockaddr_in *)(sa))
 156         hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr,
 157                 sizeof (struct in_addr), AF_INET);
 158         if (hp == (struct hostent *)0) {
 159                 rp->answer = MACHINE_UNKNOWN;
 160                 return;
 161         }
 162         ptr = find_request(mp);
 163         if (ptr == (CTL_MSG *) 0) {
 164                 insert_table(mp, rp);
 165                 rp->answer = announce(mp, hp->h_name);
 166                 return;
 167         }
 168         if (mp->id_num > ptr->id_num) {
 169                 /*
 170                  * This is an explicit re-announce, so update the id_num
 171                  * field to avoid duplicates and re-announce the talk.
 172                  */
 173                 ptr->id_num = new_id();
 174                 rp->id_num = htonl(ptr->id_num);
 175                 rp->answer = announce(mp, hp->h_name);
 176         } else {
 177                 /* a duplicated request, so ignore it */
 178                 rp->id_num = htonl(ptr->id_num);
 179                 rp->answer = SUCCESS;
 180         }
 181 }
 182
 183 #include <utmp.h>
 184
 185 /*
 186  * Search utmp for the local user
 187  */
 188 int
 189 find_user(const char *name, char *tty)
 190 {
 191         struct utmp ubuf;
 192         int status;
 193         FILE *fd;
 194         struct stat statb;
 195         time_t best = 0;
 196         char line[sizeof(ubuf.ut_line) + 1];
 197         char ftty[sizeof(_PATH_DEV) - 1 + sizeof(line)];
 198
 199         if ((fd = fopen(_PATH_UTMP, "r")) == NULL) {
 200                 warnx("can't read %s", _PATH_UTMP);
 201                 return (FAILED);
 202         }
 203 #define SCMPN(a, b)     strncmp(a, b, sizeof (a))
 204         status = NOT_HERE;
 205         (void) strcpy(ftty, _PATH_DEV);
 206         while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1)
 207                 if (SCMPN(ubuf.ut_name, name) == 0) {
 208                         strncpy(line, ubuf.ut_line, sizeof(ubuf.ut_line));
 209                         line[sizeof(ubuf.ut_line)] = '\0';
 210                         if (*tty == '\0' || best != 0) {
 211                                 if (best == 0)
 212                                         status = PERMISSION_DENIED;
 213                                 /* no particular tty was requested */
 214                                 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1,
 215                                     line);
 216                                 if (stat(ftty, &statb) == 0) {
 217                                         if (!(statb.st_mode & 020))
 218                                                 continue;
 219                                         if (statb.st_atime > best) {
 220                                                 best = statb.st_atime;
 221                                                 (void) strcpy(tty, line);
 222                                                 status = SUCCESS;
 223                                                 continue;
 224                                         }
 225                                 }
 226                         }
 227                         if (strcmp(line, tty) == 0) {
 228                                 status = SUCCESS;
 229                                 break;
 230                         }
 231                 }
 232         fclose(fd);
 233         return (status);
 234 }