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  * @(#)process.c        8.2 (Berkeley) 11/16/93
  34  * $FreeBSD: src/libexec/talkd/process.c,v 1.9 1999/08/28 00:10:16 peter Exp $
  35  * $DragonFly: src/libexec/talkd/process.c,v 1.3 2003/11/14 03:54:31 dillon Exp $
  36  */
  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
  59 int announce (CTL_MSG *, char *);
  60 int delete_invite (int);
  61 void do_announce (CTL_MSG *, CTL_RESPONSE *);
  62 CTL_MSG *find_request();
  63 CTL_MSG *find_match();
  64 int find_user (char *, char *);
  65 void insert_table (CTL_MSG *, CTL_RESPONSE *);
  66 int new_id (void);
  67 void print_request (char *, CTL_MSG *);
  68 void print_response (char *, CTL_RESPONSE *);
  69
  70 void
  71 process_request(mp, rp)
  72         register CTL_MSG *mp;
  73         register CTL_RESPONSE *rp;
  74 {
  75         register CTL_MSG *ptr;
  76         extern int debug;
  77         char *s;
  78
  79         rp->vers = TALK_VERSION;
  80         rp->type = mp->type;
  81         rp->id_num = htonl(0);
  82         if (mp->vers != TALK_VERSION) {
  83                 syslog(LOG_WARNING, "bad protocol version %d", mp->vers);
  84                 rp->answer = BADVERSION;
  85                 return;
  86         }
  87         mp->id_num = ntohl(mp->id_num);
  88         mp->addr.sa_family = ntohs(mp->addr.sa_family);
  89         if (mp->addr.sa_family != AF_INET) {
  90                 syslog(LOG_WARNING, "bad address, family %d",
  91                     mp->addr.sa_family);
  92                 rp->answer = BADADDR;
  93                 return;
  94         }
  95         mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
  96         if (mp->ctl_addr.sa_family != AF_INET) {
  97                 syslog(LOG_WARNING, "bad control address, family %d",
  98                     mp->ctl_addr.sa_family);
  99                 rp->answer = BADCTLADDR;
 100                 return;
 101         }
 102         for (s = mp->l_name; *s; s++)
 103                 if (!isprint(*s)) {
 104                         syslog(LOG_NOTICE, "illegal user name. Aborting");
 105                         rp->answer = FAILED;
 106                         return;
 107                 }
 108         mp->pid = ntohl(mp->pid);
 109         if (debug)
 110                 print_request("process_request", mp);
 111         switch (mp->type) {
 112
 113         case ANNOUNCE:
 114                 do_announce(mp, rp);
 115                 break;
 116
 117         case LEAVE_INVITE:
 118                 ptr = find_request(mp);
 119                 if (ptr != (CTL_MSG *)0) {
 120                         rp->id_num = htonl(ptr->id_num);
 121                         rp->answer = SUCCESS;
 122                 } else
 123                         insert_table(mp, rp);
 124                 break;
 125
 126         case LOOK_UP:
 127                 ptr = find_match(mp);
 128                 if (ptr != (CTL_MSG *)0) {
 129                         rp->id_num = htonl(ptr->id_num);
 130                         rp->addr = ptr->addr;
 131                         rp->addr.sa_family = htons(ptr->addr.sa_family);
 132                         rp->answer = SUCCESS;
 133                 } else
 134                         rp->answer = NOT_HERE;
 135                 break;
 136
 137         case DELETE:
 138                 rp->answer = delete_invite(mp->id_num);
 139                 break;
 140
 141         default:
 142                 rp->answer = UNKNOWN_REQUEST;
 143                 break;
 144         }
 145         if (debug)
 146                 print_response("process_request", rp);
 147 }
 148
 149 void
 150 do_announce(mp, rp)
 151         register CTL_MSG *mp;
 152         CTL_RESPONSE *rp;
 153 {
 154         struct hostent *hp;
 155         CTL_MSG *ptr;
 156         int result;
 157
 158         /* see if the user is logged */
 159         result = find_user(mp->r_name, mp->r_tty);
 160         if (result != SUCCESS) {
 161                 rp->answer = result;
 162                 return;
 163         }
 164 #define satosin(sa)     ((struct sockaddr_in *)(sa))
 165         hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr,
 166                 sizeof (struct in_addr), AF_INET);
 167         if (hp == (struct hostent *)0) {
 168                 rp->answer = MACHINE_UNKNOWN;
 169                 return;
 170         }
 171         ptr = find_request(mp);
 172         if (ptr == (CTL_MSG *) 0) {
 173                 insert_table(mp, rp);
 174                 rp->answer = announce(mp, hp->h_name);
 175                 return;
 176         }
 177         if (mp->id_num > ptr->id_num) {
 178                 /*
 179                  * This is an explicit re-announce, so update the id_num
 180                  * field to avoid duplicates and re-announce the talk.
 181                  */
 182                 ptr->id_num = new_id();
 183                 rp->id_num = htonl(ptr->id_num);
 184                 rp->answer = announce(mp, hp->h_name);
 185         } else {
 186                 /* a duplicated request, so ignore it */
 187                 rp->id_num = htonl(ptr->id_num);
 188                 rp->answer = SUCCESS;
 189         }
 190 }
 191
 192 #include <utmp.h>
 193
 194 /*
 195  * Search utmp for the local user
 196  */
 197 int
 198 find_user(name, tty)
 199         char *name, *tty;
 200 {
 201         struct utmp ubuf;
 202         int status;
 203         FILE *fd;
 204         struct stat statb;
 205         time_t best = 0;
 206         char line[sizeof(ubuf.ut_line) + 1];
 207         char ftty[sizeof(_PATH_DEV) - 1 + sizeof(line)];
 208
 209         if ((fd = fopen(_PATH_UTMP, "r")) == NULL) {
 210                 warnx("can't read %s", _PATH_UTMP);
 211                 return (FAILED);
 212         }
 213 #define SCMPN(a, b)     strncmp(a, b, sizeof (a))
 214         status = NOT_HERE;
 215         (void) strcpy(ftty, _PATH_DEV);
 216         while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1)
 217                 if (SCMPN(ubuf.ut_name, name) == 0) {
 218                         strncpy(line, ubuf.ut_line, sizeof(ubuf.ut_line));
 219                         line[sizeof(ubuf.ut_line)] = '\0';
 220                         if (*tty == '\0' || best != 0) {
 221                                 if (best == 0)
 222                                         status = PERMISSION_DENIED;
 223                                 /* no particular tty was requested */
 224                                 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1,
 225                                     line);
 226                                 if (stat(ftty, &statb) == 0) {
 227                                         if (!(statb.st_mode & 020))
 228                                                 continue;
 229                                         if (statb.st_atime > best) {
 230                                                 best = statb.st_atime;
 231                                                 (void) strcpy(tty, line);
 232                                                 status = SUCCESS;
 233                                                 continue;
 234                                         }
 235                                 }
 236                         }
 237                         if (strcmp(line, tty) == 0) {
 238                                 status = SUCCESS;
 239                                 break;
 240                         }
 241                 }
 242         fclose(fd);
 243         return (status);
 244 }