process.c revision 1592
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 35static char sccsid[] = "@(#)process.c 8.2 (Berkeley) 11/16/93"; 36#endif /* not lint */ 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 <netdb.h> 52#include <syslog.h> 53#include <stdio.h> 54#include <string.h> 55#include <paths.h> 56 57CTL_MSG *find_request(); 58CTL_MSG *find_match(); 59 60process_request(mp, rp) 61 register CTL_MSG *mp; 62 register CTL_RESPONSE *rp; 63{ 64 register CTL_MSG *ptr; 65 extern int debug; 66 67 rp->vers = TALK_VERSION; 68 rp->type = mp->type; 69 rp->id_num = htonl(0); 70 if (mp->vers != TALK_VERSION) { 71 syslog(LOG_WARNING, "Bad protocol version %d", mp->vers); 72 rp->answer = BADVERSION; 73 return; 74 } 75 mp->id_num = ntohl(mp->id_num); 76 mp->addr.sa_family = ntohs(mp->addr.sa_family); 77 if (mp->addr.sa_family != AF_INET) { 78 syslog(LOG_WARNING, "Bad address, family %d", 79 mp->addr.sa_family); 80 rp->answer = BADADDR; 81 return; 82 } 83 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 84 if (mp->ctl_addr.sa_family != AF_INET) { 85 syslog(LOG_WARNING, "Bad control address, family %d", 86 mp->ctl_addr.sa_family); 87 rp->answer = BADCTLADDR; 88 return; 89 } 90 mp->pid = ntohl(mp->pid); 91 if (debug) 92 print_request("process_request", mp); 93 switch (mp->type) { 94 95 case ANNOUNCE: 96 do_announce(mp, rp); 97 break; 98 99 case LEAVE_INVITE: 100 ptr = find_request(mp); 101 if (ptr != (CTL_MSG *)0) { 102 rp->id_num = htonl(ptr->id_num); 103 rp->answer = SUCCESS; 104 } else 105 insert_table(mp, rp); 106 break; 107 108 case LOOK_UP: 109 ptr = find_match(mp); 110 if (ptr != (CTL_MSG *)0) { 111 rp->id_num = htonl(ptr->id_num); 112 rp->addr = ptr->addr; 113 rp->addr.sa_family = htons(ptr->addr.sa_family); 114 rp->answer = SUCCESS; 115 } else 116 rp->answer = NOT_HERE; 117 break; 118 119 case DELETE: 120 rp->answer = delete_invite(mp->id_num); 121 break; 122 123 default: 124 rp->answer = UNKNOWN_REQUEST; 125 break; 126 } 127 if (debug) 128 print_response("process_request", rp); 129} 130 131do_announce(mp, rp) 132 register CTL_MSG *mp; 133 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 *)(sa)) 146 hp = gethostbyaddr((char *)&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#include <utmp.h> 174 175/* 176 * Search utmp for the local user 177 */ 178find_user(name, tty) 179 char *name, *tty; 180{ 181 struct utmp ubuf; 182 int status; 183 FILE *fd; 184 struct stat statb; 185 char line[sizeof(ubuf.ut_line) + 1]; 186 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(line)]; 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 strncpy(line, ubuf.ut_line, sizeof(ubuf.ut_line)); 198 line[sizeof(ubuf.ut_line)] = '\0'; 199 if (*tty == '\0') { 200 status = PERMISSION_DENIED; 201 /* no particular tty was requested */ 202 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1, 203 line); 204 if (stat(ftty, &statb) == 0) { 205 if (!(statb.st_mode & 020)) 206 continue; 207 (void) strcpy(tty, line); 208 status = SUCCESS; 209 break; 210 } 211 } 212 if (strcmp(line, tty) == 0) { 213 status = SUCCESS; 214 break; 215 } 216 } 217 fclose(fd); 218 return (status); 219} 220