1 /* 2 * Copyright (c) 1983 Regents of the University of California. 3 * 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 /*static char sccsid[] = "from: @(#)process.c 5.10 (Berkeley) 2/26/91";*/ 36 static char rcsid[] = "$Id: process.c,v 1.2 1993/08/01 18:29:34 mycroft Exp $"; 37 #endif /* not lint */ 38 39 /* 40 * process.c handles the requests, which can be of three types: 41 * ANNOUNCE - announce to a user that a talk is wanted 42 * LEAVE_INVITE - insert the request into the table 43 * LOOK_UP - look up to see if a request is waiting in 44 * in the table for the local user 45 * DELETE - delete invitation 46 */ 47 #include <sys/param.h> 48 #include <sys/stat.h> 49 #include <sys/socket.h> 50 #include <netinet/in.h> 51 #include <protocols/talkd.h> 52 #include <netdb.h> 53 #include <syslog.h> 54 #include <stdio.h> 55 #include <string.h> 56 #include <paths.h> 57 58 CTL_MSG *find_request(); 59 CTL_MSG *find_match(); 60 61 process_request(mp, rp) 62 register CTL_MSG *mp; 63 register CTL_RESPONSE *rp; 64 { 65 register CTL_MSG *ptr; 66 extern int debug; 67 68 rp->vers = TALK_VERSION; 69 rp->type = mp->type; 70 rp->id_num = htonl(0); 71 if (mp->vers != TALK_VERSION) { 72 syslog(LOG_WARNING, "Bad protocol version %d", mp->vers); 73 rp->answer = BADVERSION; 74 return; 75 } 76 mp->id_num = ntohl(mp->id_num); 77 mp->addr.sa_family = ntohs(mp->addr.sa_family); 78 if (mp->addr.sa_family != AF_INET) { 79 syslog(LOG_WARNING, "Bad address, family %d", 80 mp->addr.sa_family); 81 rp->answer = BADADDR; 82 return; 83 } 84 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 85 if (mp->ctl_addr.sa_family != AF_INET) { 86 syslog(LOG_WARNING, "Bad control address, family %d", 87 mp->ctl_addr.sa_family); 88 rp->answer = BADCTLADDR; 89 return; 90 } 91 mp->pid = ntohl(mp->pid); 92 if (debug) 93 print_request("process_request", mp); 94 switch (mp->type) { 95 96 case ANNOUNCE: 97 do_announce(mp, rp); 98 break; 99 100 case LEAVE_INVITE: 101 ptr = find_request(mp); 102 if (ptr != (CTL_MSG *)0) { 103 rp->id_num = htonl(ptr->id_num); 104 rp->answer = SUCCESS; 105 } else 106 insert_table(mp, rp); 107 break; 108 109 case LOOK_UP: 110 ptr = find_match(mp); 111 if (ptr != (CTL_MSG *)0) { 112 rp->id_num = htonl(ptr->id_num); 113 rp->addr = ptr->addr; 114 rp->addr.sa_family = htons(ptr->addr.sa_family); 115 rp->answer = SUCCESS; 116 } else 117 rp->answer = NOT_HERE; 118 break; 119 120 case DELETE: 121 rp->answer = delete_invite(mp->id_num); 122 break; 123 124 default: 125 rp->answer = UNKNOWN_REQUEST; 126 break; 127 } 128 if (debug) 129 print_response("process_request", rp); 130 } 131 132 do_announce(mp, rp) 133 register CTL_MSG *mp; 134 CTL_RESPONSE *rp; 135 { 136 struct hostent *hp; 137 CTL_MSG *ptr; 138 int result; 139 140 /* see if the user is logged */ 141 result = find_user(mp->r_name, mp->r_tty); 142 if (result != SUCCESS) { 143 rp->answer = result; 144 return; 145 } 146 #define satosin(sa) ((struct sockaddr_in *)(sa)) 147 hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr, 148 sizeof (struct in_addr), AF_INET); 149 if (hp == (struct hostent *)0) { 150 rp->answer = MACHINE_UNKNOWN; 151 return; 152 } 153 ptr = find_request(mp); 154 if (ptr == (CTL_MSG *) 0) { 155 insert_table(mp, rp); 156 rp->answer = announce(mp, hp->h_name); 157 return; 158 } 159 if (mp->id_num > ptr->id_num) { 160 /* 161 * This is an explicit re-announce, so update the id_num 162 * field to avoid duplicates and re-announce the talk. 163 */ 164 ptr->id_num = new_id(); 165 rp->id_num = htonl(ptr->id_num); 166 rp->answer = announce(mp, hp->h_name); 167 } else { 168 /* a duplicated request, so ignore it */ 169 rp->id_num = htonl(ptr->id_num); 170 rp->answer = SUCCESS; 171 } 172 } 173 174 #include <utmp.h> 175 176 /* 177 * Search utmp for the local user 178 */ 179 find_user(name, tty) 180 char *name, *tty; 181 { 182 struct utmp ubuf; 183 int status; 184 FILE *fd; 185 struct stat statb; 186 char ftty[20]; 187 188 if ((fd = fopen(_PATH_UTMP, "r")) == NULL) { 189 fprintf(stderr, "talkd: can't read %s.\n", _PATH_UTMP); 190 return (FAILED); 191 } 192 #define SCMPN(a, b) strncmp(a, b, sizeof (a)) 193 status = NOT_HERE; 194 (void) strcpy(ftty, _PATH_DEV); 195 while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) 196 if (SCMPN(ubuf.ut_name, name) == 0) { 197 if (*tty == '\0') { 198 status = PERMISSION_DENIED; 199 /* no particular tty was requested */ 200 (void) strcpy(ftty+5, ubuf.ut_line); 201 if (stat(ftty,&statb) == 0) { 202 if (!(statb.st_mode & 020)) 203 continue; 204 (void) strcpy(tty, ubuf.ut_line); 205 status = SUCCESS; 206 break; 207 } 208 } 209 if (strcmp(ubuf.ut_line, tty) == 0) { 210 status = SUCCESS; 211 break; 212 } 213 } 214 fclose(fd); 215 return (status); 216 } 217