1 /* $OpenBSD: process.c,v 1.10 2001/12/07 18:45:33 mpech Exp $ */ 2 3 /* 4 * Copyright (c) 1983 Regents of the University of California. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifndef lint 37 /*static char sccsid[] = "from: @(#)process.c 5.10 (Berkeley) 2/26/91";*/ 38 static char rcsid[] = "$Id: process.c,v 1.10 2001/12/07 18:45:33 mpech Exp $"; 39 #endif /* not lint */ 40 41 /* 42 * process.c handles the requests, which can be of three types: 43 * ANNOUNCE - announce to a user that a talk is wanted 44 * LEAVE_INVITE - insert the request into the table 45 * LOOK_UP - look up to see if a request is waiting in 46 * in the table for the local user 47 * DELETE - delete invitation 48 */ 49 #include <sys/param.h> 50 #include <sys/stat.h> 51 #include <sys/socket.h> 52 #include <netinet/in.h> 53 #include <arpa/inet.h> 54 #include <protocols/talkd.h> 55 #include <netdb.h> 56 #include <syslog.h> 57 #include <stdio.h> 58 #include <string.h> 59 #include <ctype.h> 60 #include <paths.h> 61 #include "talkd.h" 62 63 #define satosin(sa) ((struct sockaddr_in *)(sa)) 64 65 void 66 process_request(mp, rp) 67 CTL_MSG *mp; 68 CTL_RESPONSE *rp; 69 { 70 CTL_MSG *ptr; 71 char *s; 72 73 rp->vers = TALK_VERSION; 74 rp->type = mp->type; 75 rp->id_num = htonl(0); 76 if (mp->vers != TALK_VERSION) { 77 syslog(LOG_WARNING, "Bad protocol version %d", mp->vers); 78 rp->answer = BADVERSION; 79 return; 80 } 81 mp->id_num = ntohl(mp->id_num); 82 if (ntohs(mp->addr.sa_family) != AF_INET) { 83 syslog(LOG_WARNING, "Bad address, family %d", 84 ntohs(mp->addr.sa_family)); 85 rp->answer = BADADDR; 86 return; 87 } 88 if (ntohs(mp->ctl_addr.sa_family) != AF_INET) { 89 syslog(LOG_WARNING, "Bad control address, family %d", 90 ntohs(mp->ctl_addr.sa_family)); 91 rp->answer = BADCTLADDR; 92 return; 93 } 94 for (s = mp->l_name; *s; s++) 95 if (!isprint(*s)) { 96 syslog(LOG_NOTICE, "Illegal user name. Aborting"); 97 rp->answer = FAILED; 98 return; 99 } 100 if (memcmp(&satosin(&rp->addr)->sin_addr, 101 &satosin(&mp->ctl_addr)->sin_addr, 102 sizeof(struct in_addr))) { 103 char buf1[32], buf2[32]; 104 strcpy(buf1, inet_ntoa(satosin(&rp->addr)->sin_addr)); 105 strcpy(buf2, inet_ntoa(satosin(&mp->ctl_addr)->sin_addr)); 106 syslog(LOG_WARNING, "addresses are different, %s != %s", 107 buf1, buf2); 108 } 109 rp->addr.sa_family = 0; 110 mp->pid = ntohl(mp->pid); 111 if (debug) 112 print_request("process_request", mp); 113 switch (mp->type) { 114 115 case ANNOUNCE: 116 do_announce(mp, rp); 117 break; 118 119 case LEAVE_INVITE: 120 ptr = find_request(mp); 121 if (ptr != (CTL_MSG *)0) { 122 rp->id_num = htonl(ptr->id_num); 123 rp->answer = SUCCESS; 124 } else 125 insert_table(mp, rp); 126 break; 127 128 case LOOK_UP: 129 ptr = find_match(mp); 130 if (ptr != (CTL_MSG *)0) { 131 rp->id_num = htonl(ptr->id_num); 132 rp->addr = ptr->addr; 133 rp->addr.sa_family = ptr->addr.sa_family; 134 rp->answer = SUCCESS; 135 } else 136 rp->answer = NOT_HERE; 137 break; 138 139 case DELETE: 140 rp->answer = delete_invite(mp->id_num); 141 break; 142 143 default: 144 rp->answer = UNKNOWN_REQUEST; 145 break; 146 } 147 if (debug) 148 print_response("process_request", rp); 149 } 150 151 void 152 do_announce(mp, rp) 153 CTL_MSG *mp; 154 CTL_RESPONSE *rp; 155 { 156 struct hostent *hp; 157 CTL_MSG *ptr; 158 int result; 159 160 /* see if the user is logged */ 161 result = find_user(mp->r_name, mp->r_tty); 162 if (result != SUCCESS) { 163 rp->answer = result; 164 return; 165 } 166 hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr, 167 sizeof (struct in_addr), AF_INET); 168 if (hp == (struct hostent *)0) { 169 rp->answer = MACHINE_UNKNOWN; 170 return; 171 } 172 ptr = find_request(mp); 173 if (ptr == (CTL_MSG *) 0) { 174 insert_table(mp, rp); 175 rp->answer = announce(mp, hp->h_name); 176 return; 177 } 178 if (mp->id_num > ptr->id_num) { 179 /* 180 * This is an explicit re-announce, so update the id_num 181 * field to avoid duplicates and re-announce the talk. 182 */ 183 ptr->id_num = new_id(); 184 rp->id_num = htonl(ptr->id_num); 185 rp->answer = announce(mp, hp->h_name); 186 } else { 187 /* a duplicated request, so ignore it */ 188 rp->id_num = htonl(ptr->id_num); 189 rp->answer = SUCCESS; 190 } 191 } 192 193 #include <utmp.h> 194 195 /* 196 * Search utmp for the local user 197 */ 198 int 199 find_user(name, tty) 200 char *name, *tty; 201 { 202 struct utmp ubuf, ubuf1; 203 int status; 204 FILE *fd; 205 char ftty[20]; 206 time_t idle, now; 207 208 time(&now); 209 idle = INT_MAX; 210 if ((fd = fopen(_PATH_UTMP, "r")) == NULL) { 211 fprintf(stderr, "talkd: can't read %s.\n", _PATH_UTMP); 212 return (FAILED); 213 } 214 #define SCMPN(a, b) strncmp(a, b, sizeof (a)) 215 status = NOT_HERE; 216 (void) strcpy(ftty, _PATH_DEV); 217 while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) 218 if (SCMPN(ubuf.ut_name, name) == 0) { 219 if (*tty == '\0') { 220 /* no particular tty was requested */ 221 struct stat statb; 222 223 strcpy(ftty+sizeof(_PATH_DEV)-1, ubuf.ut_line); 224 if (stat(ftty, &statb) == 0) { 225 if (!(statb.st_mode & S_IWGRP)) { 226 if (status == NOT_HERE) 227 status = PERMISSION_DENIED; 228 } else if (now - statb.st_atime < idle) { 229 idle = now - statb.st_atime; 230 status = SUCCESS; 231 ubuf1 = ubuf; 232 } 233 } 234 } else if (strcmp(ubuf.ut_line, tty) == 0) { 235 status = SUCCESS; 236 break; 237 } 238 } 239 fclose(fd); 240 if (*tty == '\0' && status == SUCCESS) 241 strcpy(tty, ubuf1.ut_line); 242 return (status); 243 } 244