process.c revision 3791
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 if (strchr(mp->l_name, 27)) { 91 syslog(LOG_NOTICE, "Illegal user name. Aborting"); 92 rp->answer = FAILED; 93 return; 94 } 95 mp->pid = ntohl(mp->pid); 96 if (debug) 97 print_request("process_request", mp); 98 switch (mp->type) { 99 100 case ANNOUNCE: 101 do_announce(mp, rp); 102 break; 103 104 case LEAVE_INVITE: 105 ptr = find_request(mp); 106 if (ptr != (CTL_MSG *)0) { 107 rp->id_num = htonl(ptr->id_num); 108 rp->answer = SUCCESS; 109 } else 110 insert_table(mp, rp); 111 break; 112 113 case LOOK_UP: 114 ptr = find_match(mp); 115 if (ptr != (CTL_MSG *)0) { 116 rp->id_num = htonl(ptr->id_num); 117 rp->addr = ptr->addr; 118 rp->addr.sa_family = htons(ptr->addr.sa_family); 119 rp->answer = SUCCESS; 120 } else 121 rp->answer = NOT_HERE; 122 break; 123 124 case DELETE: 125 rp->answer = delete_invite(mp->id_num); 126 break; 127 128 default: 129 rp->answer = UNKNOWN_REQUEST; 130 break; 131 } 132 if (debug) 133 print_response("process_request", rp); 134} 135 136do_announce(mp, rp) 137 register CTL_MSG *mp; 138 CTL_RESPONSE *rp; 139{ 140 struct hostent *hp; 141 CTL_MSG *ptr; 142 int result; 143 144 /* see if the user is logged */ 145 result = find_user(mp->r_name, mp->r_tty); 146 if (result != SUCCESS) { 147 rp->answer = result; 148 return; 149 } 150#define satosin(sa) ((struct sockaddr_in *)(sa)) 151 hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr, 152 sizeof (struct in_addr), AF_INET); 153 if (hp == (struct hostent *)0) { 154 rp->answer = MACHINE_UNKNOWN; 155 return; 156 } 157 ptr = find_request(mp); 158 if (ptr == (CTL_MSG *) 0) { 159 insert_table(mp, rp); 160 rp->answer = announce(mp, hp->h_name); 161 return; 162 } 163 if (mp->id_num > ptr->id_num) { 164 /* 165 * This is an explicit re-announce, so update the id_num 166 * field to avoid duplicates and re-announce the talk. 167 */ 168 ptr->id_num = new_id(); 169 rp->id_num = htonl(ptr->id_num); 170 rp->answer = announce(mp, hp->h_name); 171 } else { 172 /* a duplicated request, so ignore it */ 173 rp->id_num = htonl(ptr->id_num); 174 rp->answer = SUCCESS; 175 } 176} 177 178#include <utmp.h> 179 180/* 181 * Search utmp for the local user 182 */ 183find_user(name, tty) 184 char *name, *tty; 185{ 186 struct utmp ubuf; 187 int status; 188 FILE *fd; 189 struct stat statb; 190 char line[sizeof(ubuf.ut_line) + 1]; 191 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(line)]; 192 193 if ((fd = fopen(_PATH_UTMP, "r")) == NULL) { 194 fprintf(stderr, "talkd: can't read %s.\n", _PATH_UTMP); 195 return (FAILED); 196 } 197#define SCMPN(a, b) strncmp(a, b, sizeof (a)) 198 status = NOT_HERE; 199 (void) strcpy(ftty, _PATH_DEV); 200 while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) 201 if (SCMPN(ubuf.ut_name, name) == 0) { 202 strncpy(line, ubuf.ut_line, sizeof(ubuf.ut_line)); 203 line[sizeof(ubuf.ut_line)] = '\0'; 204 if (*tty == '\0') { 205 status = PERMISSION_DENIED; 206 /* no particular tty was requested */ 207 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1, 208 line); 209 if (stat(ftty, &statb) == 0) { 210 if (!(statb.st_mode & 020)) 211 continue; 212 (void) strcpy(tty, line); 213 status = SUCCESS; 214 break; 215 } 216 } 217 if (strcmp(line, tty) == 0) { 218 status = SUCCESS; 219 break; 220 } 221 } 222 fclose(fd); 223 return (status); 224} 225