1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1983, 1993 5 * The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * process.c handles the requests, which can be of three types: 34 * ANNOUNCE - announce to a user that a talk is wanted 35 * LEAVE_INVITE - insert the request into the table 36 * LOOK_UP - look up to see if a request is waiting in 37 * in the table for the local user 38 * DELETE - delete invitation 39 */ 40 #include <sys/param.h> 41 #include <sys/stat.h> 42 #include <sys/socket.h> 43 #include <netinet/in.h> 44 #include <protocols/talkd.h> 45 #include <ctype.h> 46 #include <err.h> 47 #include <netdb.h> 48 #include <paths.h> 49 #include <stdio.h> 50 #include <string.h> 51 #include <syslog.h> 52 #include <utmpx.h> 53 54 #include "extern.h" 55 56 void 57 process_request(CTL_MSG *mp, CTL_RESPONSE *rp) 58 { 59 CTL_MSG *ptr; 60 char *s; 61 62 rp->vers = TALK_VERSION; 63 rp->type = mp->type; 64 rp->id_num = htonl(0); 65 if (mp->vers != TALK_VERSION) { 66 syslog(LOG_WARNING, "bad protocol version %d", mp->vers); 67 rp->answer = BADVERSION; 68 return; 69 } 70 mp->id_num = ntohl(mp->id_num); 71 mp->addr.sa_family = ntohs(mp->addr.sa_family); 72 if (mp->addr.sa_family != AF_INET) { 73 syslog(LOG_WARNING, "bad address, family %d", 74 mp->addr.sa_family); 75 rp->answer = BADADDR; 76 return; 77 } 78 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 79 if (mp->ctl_addr.sa_family != AF_INET) { 80 syslog(LOG_WARNING, "bad control address, family %d", 81 mp->ctl_addr.sa_family); 82 rp->answer = BADCTLADDR; 83 return; 84 } 85 for (s = mp->l_name; *s; s++) 86 if (!isprint(*s)) { 87 syslog(LOG_NOTICE, "illegal user name. Aborting"); 88 rp->answer = FAILED; 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 void 133 do_announce(CTL_MSG *mp, CTL_RESPONSE *rp) 134 { 135 struct hostent *hp; 136 CTL_MSG *ptr; 137 int result; 138 139 /* see if the user is logged */ 140 result = find_user(mp->r_name, mp->r_tty); 141 if (result != SUCCESS) { 142 rp->answer = result; 143 return; 144 } 145 #define satosin(sa) ((struct sockaddr_in *)(void *)(sa)) 146 hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr, 147 sizeof (struct in_addr), AF_INET); 148 if (hp == (struct hostent *)0) { 149 rp->answer = MACHINE_UNKNOWN; 150 return; 151 } 152 ptr = find_request(mp); 153 if (ptr == (CTL_MSG *) 0) { 154 insert_table(mp, rp); 155 rp->answer = announce(mp, hp->h_name); 156 return; 157 } 158 if (mp->id_num > ptr->id_num) { 159 /* 160 * This is an explicit re-announce, so update the id_num 161 * field to avoid duplicates and re-announce the talk. 162 */ 163 ptr->id_num = new_id(); 164 rp->id_num = htonl(ptr->id_num); 165 rp->answer = announce(mp, hp->h_name); 166 } else { 167 /* a duplicated request, so ignore it */ 168 rp->id_num = htonl(ptr->id_num); 169 rp->answer = SUCCESS; 170 } 171 } 172 173 /* 174 * Search utmp for the local user 175 */ 176 int 177 find_user(const char *name, char *tty) 178 { 179 struct utmpx *ut; 180 int status; 181 struct stat statb; 182 time_t best = 0; 183 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(ut->ut_line)]; 184 185 setutxent(); 186 status = NOT_HERE; 187 (void) strcpy(ftty, _PATH_DEV); 188 while ((ut = getutxent()) != NULL) 189 if (ut->ut_type == USER_PROCESS && 190 strcmp(ut->ut_user, name) == 0) { 191 if (*tty == '\0' || best != 0) { 192 if (best == 0) 193 status = PERMISSION_DENIED; 194 /* no particular tty was requested */ 195 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1, 196 ut->ut_line); 197 if (stat(ftty, &statb) == 0) { 198 if (!(statb.st_mode & 020)) 199 continue; 200 if (statb.st_atime > best) { 201 best = statb.st_atime; 202 (void) strcpy(tty, ut->ut_line); 203 status = SUCCESS; 204 continue; 205 } 206 } 207 } 208 if (strcmp(ut->ut_line, tty) == 0) { 209 status = SUCCESS; 210 break; 211 } 212 } 213 endutxent(); 214 return (status); 215 } 216