process.c revision 22989
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 * $Id$ 34 */ 35 36#ifndef lint 37static char sccsid[] = "@(#)process.c 8.2 (Berkeley) 11/16/93"; 38#endif /* not lint */ 39 40/* 41 * process.c handles the requests, which can be of three types: 42 * ANNOUNCE - announce to a user that a talk is wanted 43 * LEAVE_INVITE - insert the request into the table 44 * LOOK_UP - look up to see if a request is waiting in 45 * in the table for the local user 46 * DELETE - delete invitation 47 */ 48#include <sys/param.h> 49#include <sys/stat.h> 50#include <sys/socket.h> 51#include <netinet/in.h> 52#include <protocols/talkd.h> 53#include <netdb.h> 54#include <syslog.h> 55#include <stdio.h> 56#include <string.h> 57#include <ctype.h> 58#include <paths.h> 59 60CTL_MSG *find_request(); 61CTL_MSG *find_match(); 62 63process_request(mp, rp) 64 register CTL_MSG *mp; 65 register CTL_RESPONSE *rp; 66{ 67 register CTL_MSG *ptr; 68 extern int debug; 69 char *s; 70 71 rp->vers = TALK_VERSION; 72 rp->type = mp->type; 73 rp->id_num = htonl(0); 74 if (mp->vers != TALK_VERSION) { 75 syslog(LOG_WARNING, "Bad protocol version %d", mp->vers); 76 rp->answer = BADVERSION; 77 return; 78 } 79 mp->id_num = ntohl(mp->id_num); 80 mp->addr.sa_family = ntohs(mp->addr.sa_family); 81 if (mp->addr.sa_family != AF_INET) { 82 syslog(LOG_WARNING, "Bad address, family %d", 83 mp->addr.sa_family); 84 rp->answer = BADADDR; 85 return; 86 } 87 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 88 if (mp->ctl_addr.sa_family != AF_INET) { 89 syslog(LOG_WARNING, "Bad control address, family %d", 90 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 mp->pid = ntohl(mp->pid); 101 if (debug) 102 print_request("process_request", mp); 103 switch (mp->type) { 104 105 case ANNOUNCE: 106 do_announce(mp, rp); 107 break; 108 109 case LEAVE_INVITE: 110 ptr = find_request(mp); 111 if (ptr != (CTL_MSG *)0) { 112 rp->id_num = htonl(ptr->id_num); 113 rp->answer = SUCCESS; 114 } else 115 insert_table(mp, rp); 116 break; 117 118 case LOOK_UP: 119 ptr = find_match(mp); 120 if (ptr != (CTL_MSG *)0) { 121 rp->id_num = htonl(ptr->id_num); 122 rp->addr = ptr->addr; 123 rp->addr.sa_family = htons(ptr->addr.sa_family); 124 rp->answer = SUCCESS; 125 } else 126 rp->answer = NOT_HERE; 127 break; 128 129 case DELETE: 130 rp->answer = delete_invite(mp->id_num); 131 break; 132 133 default: 134 rp->answer = UNKNOWN_REQUEST; 135 break; 136 } 137 if (debug) 138 print_response("process_request", rp); 139} 140 141do_announce(mp, rp) 142 register CTL_MSG *mp; 143 CTL_RESPONSE *rp; 144{ 145 struct hostent *hp; 146 CTL_MSG *ptr; 147 int result; 148 149 /* see if the user is logged */ 150 result = find_user(mp->r_name, mp->r_tty); 151 if (result != SUCCESS) { 152 rp->answer = result; 153 return; 154 } 155#define satosin(sa) ((struct sockaddr_in *)(sa)) 156 hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr, 157 sizeof (struct in_addr), AF_INET); 158 if (hp == (struct hostent *)0) { 159 rp->answer = MACHINE_UNKNOWN; 160 return; 161 } 162 ptr = find_request(mp); 163 if (ptr == (CTL_MSG *) 0) { 164 insert_table(mp, rp); 165 rp->answer = announce(mp, hp->h_name); 166 return; 167 } 168 if (mp->id_num > ptr->id_num) { 169 /* 170 * This is an explicit re-announce, so update the id_num 171 * field to avoid duplicates and re-announce the talk. 172 */ 173 ptr->id_num = new_id(); 174 rp->id_num = htonl(ptr->id_num); 175 rp->answer = announce(mp, hp->h_name); 176 } else { 177 /* a duplicated request, so ignore it */ 178 rp->id_num = htonl(ptr->id_num); 179 rp->answer = SUCCESS; 180 } 181} 182 183#include <utmp.h> 184 185/* 186 * Search utmp for the local user 187 */ 188find_user(name, tty) 189 char *name, *tty; 190{ 191 struct utmp ubuf; 192 int status; 193 FILE *fd; 194 struct stat statb; 195 time_t best = 0; 196 char line[sizeof(ubuf.ut_line) + 1]; 197 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(line)]; 198 199 if ((fd = fopen(_PATH_UTMP, "r")) == NULL) { 200 fprintf(stderr, "talkd: can't read %s.\n", _PATH_UTMP); 201 return (FAILED); 202 } 203#define SCMPN(a, b) strncmp(a, b, sizeof (a)) 204 status = NOT_HERE; 205 (void) strcpy(ftty, _PATH_DEV); 206 while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) 207 if (SCMPN(ubuf.ut_name, name) == 0) { 208 strncpy(line, ubuf.ut_line, sizeof(ubuf.ut_line)); 209 line[sizeof(ubuf.ut_line)] = '\0'; 210 if (*tty == '\0' || best != 0) { 211 if (best == 0) 212 status = PERMISSION_DENIED; 213 /* no particular tty was requested */ 214 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1, 215 line); 216 if (stat(ftty, &statb) == 0) { 217 if (!(statb.st_mode & 020)) 218 continue; 219 if (statb.st_atime > best) { 220 best = statb.st_atime; 221 (void) strcpy(tty, line); 222 status = SUCCESS; 223 continue; 224 } 225 } 226 } 227 if (strcmp(line, tty) == 0) { 228 status = SUCCESS; 229 break; 230 } 231 } 232 fclose(fd); 233 return (status); 234} 235