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: src/libexec/talkd/process.c,v 1.9 1999/08/28 00:10:16 peter Exp $";
  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 int announce __P((CTL_MSG *, char *));
  64 int delete_invite __P((int));
  65 void do_announce __P((CTL_MSG *, CTL_RESPONSE *));
  66 CTL_MSG *find_request();
  67 CTL_MSG *find_match();
  68 int find_user __P((char *, char *));
  69 void insert_table __P((CTL_MSG *, CTL_RESPONSE *));
  70 int new_id __P((void));
  71 void print_request __P((char *, CTL_MSG *));
  72 void print_response __P((char *, CTL_RESPONSE *));
  73
  74 void
  75 process_request(mp, rp)
  76         register CTL_MSG *mp;
  77         register CTL_RESPONSE *rp;
  78 {
  79         register CTL_MSG *ptr;
  80         extern int debug;
  81         char *s;
  82
  83         rp->vers = TALK_VERSION;
  84         rp->type = mp->type;
  85         rp->id_num = htonl(0);
  86         if (mp->vers != TALK_VERSION) {
  87                 syslog(LOG_WARNING, "bad protocol version %d", mp->vers);
  88                 rp->answer = BADVERSION;
  89                 return;
  90         }
  91         mp->id_num = ntohl(mp->id_num);
  92         mp->addr.sa_family = ntohs(mp->addr.sa_family);
  93         if (mp->addr.sa_family != AF_INET) {
  94                 syslog(LOG_WARNING, "bad address, family %d",
  95                     mp->addr.sa_family);
  96                 rp->answer = BADADDR;
  97                 return;
  98         }
  99         mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
 100         if (mp->ctl_addr.sa_family != AF_INET) {
 101                 syslog(LOG_WARNING, "bad control address, family %d",
 102                     mp->ctl_addr.sa_family);
 103                 rp->answer = BADCTLADDR;
 104                 return;
 105         }
 106         for (s = mp->l_name; *s; s++)
 107                 if (!isprint(*s)) {
 108                         syslog(LOG_NOTICE, "illegal user name. Aborting");
 109                         rp->answer = FAILED;
 110                         return;
 111                 }
 112         mp->pid = ntohl(mp->pid);
 113         if (debug)
 114                 print_request("process_request", mp);
 115         switch (mp->type) {
 116
 117         case ANNOUNCE:
 118                 do_announce(mp, rp);
 119                 break;
 120
 121         case LEAVE_INVITE:
 122                 ptr = find_request(mp);
 123                 if (ptr != (CTL_MSG *)0) {
 124                         rp->id_num = htonl(ptr->id_num);
 125                         rp->answer = SUCCESS;
 126                 } else
 127                         insert_table(mp, rp);
 128                 break;
 129
 130         case LOOK_UP:
 131                 ptr = find_match(mp);
 132                 if (ptr != (CTL_MSG *)0) {
 133                         rp->id_num = htonl(ptr->id_num);
 134                         rp->addr = ptr->addr;
 135                         rp->addr.sa_family = htons(ptr->addr.sa_family);
 136                         rp->answer = SUCCESS;
 137                 } else
 138                         rp->answer = NOT_HERE;
 139                 break;
 140
 141         case DELETE:
 142                 rp->answer = delete_invite(mp->id_num);
 143                 break;
 144
 145         default:
 146                 rp->answer = UNKNOWN_REQUEST;
 147                 break;
 148         }
 149         if (debug)
 150                 print_response("process_request", rp);
 151 }
 152
 153 void
 154 do_announce(mp, rp)
 155         register CTL_MSG *mp;
 156         CTL_RESPONSE *rp;
 157 {
 158         struct hostent *hp;
 159         CTL_MSG *ptr;
 160         int result;
 161
 162         /* see if the user is logged */
 163         result = find_user(mp->r_name, mp->r_tty);
 164         if (result != SUCCESS) {
 165                 rp->answer = result;
 166                 return;
 167         }
 168 #define satosin(sa)     ((struct sockaddr_in *)(sa))
 169         hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr,
 170                 sizeof (struct in_addr), AF_INET);
 171         if (hp == (struct hostent *)0) {
 172                 rp->answer = MACHINE_UNKNOWN;
 173                 return;
 174         }
 175         ptr = find_request(mp);
 176         if (ptr == (CTL_MSG *) 0) {
 177                 insert_table(mp, rp);
 178                 rp->answer = announce(mp, hp->h_name);
 179                 return;
 180         }
 181         if (mp->id_num > ptr->id_num) {
 182                 /*
 183                  * This is an explicit re-announce, so update the id_num
 184                  * field to avoid duplicates and re-announce the talk.
 185                  */
 186                 ptr->id_num = new_id();
 187                 rp->id_num = htonl(ptr->id_num);
 188                 rp->answer = announce(mp, hp->h_name);
 189         } else {
 190                 /* a duplicated request, so ignore it */
 191                 rp->id_num = htonl(ptr->id_num);
 192                 rp->answer = SUCCESS;
 193         }
 194 }
 195
 196 #include <utmp.h>
 197
 198 /*
 199  * Search utmp for the local user
 200  */
 201 int
 202 find_user(name, tty)
 203         char *name, *tty;
 204 {
 205         struct utmp ubuf;
 206         int status;
 207         FILE *fd;
 208         struct stat statb;
 209         time_t best = 0;
 210         char line[sizeof(ubuf.ut_line) + 1];
 211         char ftty[sizeof(_PATH_DEV) - 1 + sizeof(line)];
 212
 213         if ((fd = fopen(_PATH_UTMP, "r")) == NULL) {
 214                 warnx("can't read %s", _PATH_UTMP);
 215                 return (FAILED);
 216         }
 217 #define SCMPN(a, b)     strncmp(a, b, sizeof (a))
 218         status = NOT_HERE;
 219         (void) strcpy(ftty, _PATH_DEV);
 220         while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1)
 221                 if (SCMPN(ubuf.ut_name, name) == 0) {
 222                         strncpy(line, ubuf.ut_line, sizeof(ubuf.ut_line));
 223                         line[sizeof(ubuf.ut_line)] = '\0';
 224                         if (*tty == '\0' || best != 0) {
 225                                 if (best == 0)
 226                                         status = PERMISSION_DENIED;
 227                                 /* no particular tty was requested */
 228                                 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1,
 229                                     line);
 230                                 if (stat(ftty, &statb) == 0) {
 231                                         if (!(statb.st_mode & 020))
 232                                                 continue;
 233                                         if (statb.st_atime > best) {
 234                                                 best = statb.st_atime;
 235                                                 (void) strcpy(tty, line);
 236                                                 status = SUCCESS;
 237                                                 continue;
 238                                         }
 239                                 }
 240                         }
 241                         if (strcmp(line, tty) == 0) {
 242                                 status = SUCCESS;
 243                                 break;
 244                         }
 245                 }
 246         fclose(fd);
 247         return (status);
 248 }