process.c revision 14783
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 <ctype.h> 56#include <paths.h> 57 58CTL_MSG *find_request(); 59CTL_MSG *find_match(); 60 61process_request(mp, rp) 62 register CTL_MSG *mp; 63 register CTL_RESPONSE *rp; 64{ 65 register CTL_MSG *ptr; 66 extern int debug; 67 char *s; 68 69 rp->vers = TALK_VERSION; 70 rp->type = mp->type; 71 rp->id_num = htonl(0); 72 if (mp->vers != TALK_VERSION) { 73 syslog(LOG_WARNING, "Bad protocol version %d", mp->vers); 74 rp->answer = BADVERSION; 75 return; 76 } 77 mp->id_num = ntohl(mp->id_num); 78 mp->addr.sa_family = ntohs(mp->addr.sa_family); 79 if (mp->addr.sa_family != AF_INET) { 80 syslog(LOG_WARNING, "Bad address, family %d", 81 mp->addr.sa_family); 82 rp->answer = BADADDR; 83 return; 84 } 85 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 86 if (mp->ctl_addr.sa_family != AF_INET) { 87 syslog(LOG_WARNING, "Bad control address, family %d", 88 mp->ctl_addr.sa_family); 89 rp->answer = BADCTLADDR; 90 return; 91 } 92 for (s = mp->l_name; *s; s++) 93 if (!isprint(*s)) { 94 syslog(LOG_NOTICE, "Illegal user name. Aborting"); 95 rp->answer = FAILED; 96 return; 97 } 98 mp->pid = ntohl(mp->pid); 99 if (debug) 100 print_request("process_request", mp); 101 switch (mp->type) { 102 103 case ANNOUNCE: 104 do_announce(mp, rp); 105 break; 106 107 case LEAVE_INVITE: 108 ptr = find_request(mp); 109 if (ptr != (CTL_MSG *)0) { 110 rp->id_num = htonl(ptr->id_num); 111 rp->answer = SUCCESS; 112 } else 113 insert_table(mp, rp); 114 break; 115 116 case LOOK_UP: 117 ptr = find_match(mp); 118 if (ptr != (CTL_MSG *)0) { 119 rp->id_num = htonl(ptr->id_num); 120 rp->addr = ptr->addr; 121 rp->addr.sa_family = htons(ptr->addr.sa_family); 122 rp->answer = SUCCESS; 123 } else 124 rp->answer = NOT_HERE; 125 break; 126 127 case DELETE: 128 rp->answer = delete_invite(mp->id_num); 129 break; 130 131 default: 132 rp->answer = UNKNOWN_REQUEST; 133 break; 134 } 135 if (debug) 136 print_response("process_request", rp); 137} 138 139do_announce(mp, rp) 140 register CTL_MSG *mp; 141 CTL_RESPONSE *rp; 142{ 143 struct hostent *hp; 144 CTL_MSG *ptr; 145 int result; 146 147 /* see if the user is logged */ 148 result = find_user(mp->r_name, mp->r_tty); 149 if (result != SUCCESS) { 150 rp->answer = result; 151 return; 152 } 153#define satosin(sa) ((struct sockaddr_in *)(sa)) 154 hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr, 155 sizeof (struct in_addr), AF_INET); 156 if (hp == (struct hostent *)0) { 157 rp->answer = MACHINE_UNKNOWN; 158 return; 159 } 160 ptr = find_request(mp); 161 if (ptr == (CTL_MSG *) 0) { 162 insert_table(mp, rp); 163 rp->answer = announce(mp, hp->h_name); 164 return; 165 } 166 if (mp->id_num > ptr->id_num) { 167 /* 168 * This is an explicit re-announce, so update the id_num 169 * field to avoid duplicates and re-announce the talk. 170 */ 171 ptr->id_num = new_id(); 172 rp->id_num = htonl(ptr->id_num); 173 rp->answer = announce(mp, hp->h_name); 174 } else { 175 /* a duplicated request, so ignore it */ 176 rp->id_num = htonl(ptr->id_num); 177 rp->answer = SUCCESS; 178 } 179} 180 181#include <utmp.h> 182 183/* 184 * Search utmp for the local user 185 */ 186find_user(name, tty) 187 char *name, *tty; 188{ 189 struct utmp ubuf; 190 int status; 191 FILE *fd; 192 struct stat statb; 193 time_t best = 0; 194 char line[sizeof(ubuf.ut_line) + 1]; 195 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(line)]; 196 197 if ((fd = fopen(_PATH_UTMP, "r")) == NULL) { 198 fprintf(stderr, "talkd: can't read %s.\n", _PATH_UTMP); 199 return (FAILED); 200 } 201#define SCMPN(a, b) strncmp(a, b, sizeof (a)) 202 status = NOT_HERE; 203 (void) strcpy(ftty, _PATH_DEV); 204 while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) 205 if (SCMPN(ubuf.ut_name, name) == 0) { 206 strncpy(line, ubuf.ut_line, sizeof(ubuf.ut_line)); 207 line[sizeof(ubuf.ut_line)] = '\0'; 208 if (*tty == '\0' || best != 0) { 209 if (best == 0) 210 status = PERMISSION_DENIED; 211 /* no particular tty was requested */ 212 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1, 213 line); 214 if (stat(ftty, &statb) == 0) { 215 if (!(statb.st_mode & 020)) 216 continue; 217 if (statb.st_atime > best) { 218 best = statb.st_atime; 219 (void) strcpy(tty, line); 220 status = SUCCESS; 221 continue; 222 } 223 } 224 } 225 if (strcmp(line, tty) == 0) { 226 status = SUCCESS; 227 break; 228 } 229 } 230 fclose(fd); 231 return (status); 232} 233