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 * @(#)process.c 8.2 (Berkeley) 11/16/93 34 * $FreeBSD: src/libexec/talkd/process.c,v 1.9 1999/08/28 00:10:16 peter Exp $ 35 * $DragonFly: src/libexec/talkd/process.c,v 1.3 2003/11/14 03:54:31 dillon Exp $ 36 */ 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 <ctype.h> 52 #include <err.h> 53 #include <netdb.h> 54 #include <paths.h> 55 #include <stdio.h> 56 #include <string.h> 57 #include <syslog.h> 58 59 int announce (CTL_MSG *, char *); 60 int delete_invite (int); 61 void do_announce (CTL_MSG *, CTL_RESPONSE *); 62 CTL_MSG *find_request(); 63 CTL_MSG *find_match(); 64 int find_user (char *, char *); 65 void insert_table (CTL_MSG *, CTL_RESPONSE *); 66 int new_id (void); 67 void print_request (char *, CTL_MSG *); 68 void print_response (char *, CTL_RESPONSE *); 69 70 void 71 process_request(mp, rp) 72 register CTL_MSG *mp; 73 register CTL_RESPONSE *rp; 74 { 75 register CTL_MSG *ptr; 76 extern int debug; 77 char *s; 78 79 rp->vers = TALK_VERSION; 80 rp->type = mp->type; 81 rp->id_num = htonl(0); 82 if (mp->vers != TALK_VERSION) { 83 syslog(LOG_WARNING, "bad protocol version %d", mp->vers); 84 rp->answer = BADVERSION; 85 return; 86 } 87 mp->id_num = ntohl(mp->id_num); 88 mp->addr.sa_family = ntohs(mp->addr.sa_family); 89 if (mp->addr.sa_family != AF_INET) { 90 syslog(LOG_WARNING, "bad address, family %d", 91 mp->addr.sa_family); 92 rp->answer = BADADDR; 93 return; 94 } 95 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 96 if (mp->ctl_addr.sa_family != AF_INET) { 97 syslog(LOG_WARNING, "bad control address, family %d", 98 mp->ctl_addr.sa_family); 99 rp->answer = BADCTLADDR; 100 return; 101 } 102 for (s = mp->l_name; *s; s++) 103 if (!isprint(*s)) { 104 syslog(LOG_NOTICE, "illegal user name. Aborting"); 105 rp->answer = FAILED; 106 return; 107 } 108 mp->pid = ntohl(mp->pid); 109 if (debug) 110 print_request("process_request", mp); 111 switch (mp->type) { 112 113 case ANNOUNCE: 114 do_announce(mp, rp); 115 break; 116 117 case LEAVE_INVITE: 118 ptr = find_request(mp); 119 if (ptr != (CTL_MSG *)0) { 120 rp->id_num = htonl(ptr->id_num); 121 rp->answer = SUCCESS; 122 } else 123 insert_table(mp, rp); 124 break; 125 126 case LOOK_UP: 127 ptr = find_match(mp); 128 if (ptr != (CTL_MSG *)0) { 129 rp->id_num = htonl(ptr->id_num); 130 rp->addr = ptr->addr; 131 rp->addr.sa_family = htons(ptr->addr.sa_family); 132 rp->answer = SUCCESS; 133 } else 134 rp->answer = NOT_HERE; 135 break; 136 137 case DELETE: 138 rp->answer = delete_invite(mp->id_num); 139 break; 140 141 default: 142 rp->answer = UNKNOWN_REQUEST; 143 break; 144 } 145 if (debug) 146 print_response("process_request", rp); 147 } 148 149 void 150 do_announce(mp, rp) 151 register CTL_MSG *mp; 152 CTL_RESPONSE *rp; 153 { 154 struct hostent *hp; 155 CTL_MSG *ptr; 156 int result; 157 158 /* see if the user is logged */ 159 result = find_user(mp->r_name, mp->r_tty); 160 if (result != SUCCESS) { 161 rp->answer = result; 162 return; 163 } 164 #define satosin(sa) ((struct sockaddr_in *)(sa)) 165 hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr, 166 sizeof (struct in_addr), AF_INET); 167 if (hp == (struct hostent *)0) { 168 rp->answer = MACHINE_UNKNOWN; 169 return; 170 } 171 ptr = find_request(mp); 172 if (ptr == (CTL_MSG *) 0) { 173 insert_table(mp, rp); 174 rp->answer = announce(mp, hp->h_name); 175 return; 176 } 177 if (mp->id_num > ptr->id_num) { 178 /* 179 * This is an explicit re-announce, so update the id_num 180 * field to avoid duplicates and re-announce the talk. 181 */ 182 ptr->id_num = new_id(); 183 rp->id_num = htonl(ptr->id_num); 184 rp->answer = announce(mp, hp->h_name); 185 } else { 186 /* a duplicated request, so ignore it */ 187 rp->id_num = htonl(ptr->id_num); 188 rp->answer = SUCCESS; 189 } 190 } 191 192 #include <utmp.h> 193 194 /* 195 * Search utmp for the local user 196 */ 197 int 198 find_user(name, tty) 199 char *name, *tty; 200 { 201 struct utmp ubuf; 202 int status; 203 FILE *fd; 204 struct stat statb; 205 time_t best = 0; 206 char line[sizeof(ubuf.ut_line) + 1]; 207 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(line)]; 208 209 if ((fd = fopen(_PATH_UTMP, "r")) == NULL) { 210 warnx("can't read %s", _PATH_UTMP); 211 return (FAILED); 212 } 213 #define SCMPN(a, b) strncmp(a, b, sizeof (a)) 214 status = NOT_HERE; 215 (void) strcpy(ftty, _PATH_DEV); 216 while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) 217 if (SCMPN(ubuf.ut_name, name) == 0) { 218 strncpy(line, ubuf.ut_line, sizeof(ubuf.ut_line)); 219 line[sizeof(ubuf.ut_line)] = '\0'; 220 if (*tty == '\0' || best != 0) { 221 if (best == 0) 222 status = PERMISSION_DENIED; 223 /* no particular tty was requested */ 224 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1, 225 line); 226 if (stat(ftty, &statb) == 0) { 227 if (!(statb.st_mode & 020)) 228 continue; 229 if (statb.st_atime > best) { 230 best = statb.st_atime; 231 (void) strcpy(tty, line); 232 status = SUCCESS; 233 continue; 234 } 235 } 236 } 237 if (strcmp(line, tty) == 0) { 238 status = SUCCESS; 239 break; 240 } 241 } 242 fclose(fd); 243 return (status); 244 } 245