process.c revision 201022
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 35#if 0 36static char sccsid[] = "@(#)process.c 8.2 (Berkeley) 11/16/93"; 37#endif 38static const char rcsid[] = 39 "$FreeBSD: head/libexec/talkd/process.c 201022 2009-12-26 14:33:55Z ed $"; 40#endif /* not lint */ 41 42/* 43 * process.c handles the requests, which can be of three types: 44 * ANNOUNCE - announce to a user that a talk is wanted 45 * LEAVE_INVITE - insert the request into the table 46 * LOOK_UP - look up to see if a request is waiting in 47 * in the table for the local user 48 * DELETE - delete invitation 49 */ 50#include <sys/param.h> 51#include <sys/stat.h> 52#include <sys/socket.h> 53#include <netinet/in.h> 54#include <protocols/talkd.h> 55#include <ctype.h> 56#include <err.h> 57#include <netdb.h> 58#include <paths.h> 59#include <stdio.h> 60#include <string.h> 61#include <syslog.h> 62#define _ULOG_POSIX_NAMES 63#include <ulog.h> 64 65#include "extern.h" 66 67extern int debug; 68 69void 70process_request(CTL_MSG *mp, CTL_RESPONSE *rp) 71{ 72 CTL_MSG *ptr; 73 char *s; 74 75 rp->vers = TALK_VERSION; 76 rp->type = mp->type; 77 rp->id_num = htonl(0); 78 if (mp->vers != TALK_VERSION) { 79 syslog(LOG_WARNING, "bad protocol version %d", mp->vers); 80 rp->answer = BADVERSION; 81 return; 82 } 83 mp->id_num = ntohl(mp->id_num); 84 mp->addr.sa_family = ntohs(mp->addr.sa_family); 85 if (mp->addr.sa_family != AF_INET) { 86 syslog(LOG_WARNING, "bad address, family %d", 87 mp->addr.sa_family); 88 rp->answer = BADADDR; 89 return; 90 } 91 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 92 if (mp->ctl_addr.sa_family != AF_INET) { 93 syslog(LOG_WARNING, "bad control address, family %d", 94 mp->ctl_addr.sa_family); 95 rp->answer = BADCTLADDR; 96 return; 97 } 98 for (s = mp->l_name; *s; s++) 99 if (!isprint(*s)) { 100 syslog(LOG_NOTICE, "illegal user name. Aborting"); 101 rp->answer = FAILED; 102 return; 103 } 104 mp->pid = ntohl(mp->pid); 105 if (debug) 106 print_request("process_request", mp); 107 switch (mp->type) { 108 109 case ANNOUNCE: 110 do_announce(mp, rp); 111 break; 112 113 case LEAVE_INVITE: 114 ptr = find_request(mp); 115 if (ptr != (CTL_MSG *)0) { 116 rp->id_num = htonl(ptr->id_num); 117 rp->answer = SUCCESS; 118 } else 119 insert_table(mp, rp); 120 break; 121 122 case LOOK_UP: 123 ptr = find_match(mp); 124 if (ptr != (CTL_MSG *)0) { 125 rp->id_num = htonl(ptr->id_num); 126 rp->addr = ptr->addr; 127 rp->addr.sa_family = htons(ptr->addr.sa_family); 128 rp->answer = SUCCESS; 129 } else 130 rp->answer = NOT_HERE; 131 break; 132 133 case DELETE: 134 rp->answer = delete_invite(mp->id_num); 135 break; 136 137 default: 138 rp->answer = UNKNOWN_REQUEST; 139 break; 140 } 141 if (debug) 142 print_response("process_request", rp); 143} 144 145void 146do_announce(CTL_MSG *mp, CTL_RESPONSE *rp) 147{ 148 struct hostent *hp; 149 CTL_MSG *ptr; 150 int result; 151 152 /* see if the user is logged */ 153 result = find_user(mp->r_name, mp->r_tty); 154 if (result != SUCCESS) { 155 rp->answer = result; 156 return; 157 } 158#define satosin(sa) ((struct sockaddr_in *)(void *)(sa)) 159 hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr, 160 sizeof (struct in_addr), AF_INET); 161 if (hp == (struct hostent *)0) { 162 rp->answer = MACHINE_UNKNOWN; 163 return; 164 } 165 ptr = find_request(mp); 166 if (ptr == (CTL_MSG *) 0) { 167 insert_table(mp, rp); 168 rp->answer = announce(mp, hp->h_name); 169 return; 170 } 171 if (mp->id_num > ptr->id_num) { 172 /* 173 * This is an explicit re-announce, so update the id_num 174 * field to avoid duplicates and re-announce the talk. 175 */ 176 ptr->id_num = new_id(); 177 rp->id_num = htonl(ptr->id_num); 178 rp->answer = announce(mp, hp->h_name); 179 } else { 180 /* a duplicated request, so ignore it */ 181 rp->id_num = htonl(ptr->id_num); 182 rp->answer = SUCCESS; 183 } 184} 185 186/* 187 * Search utmp for the local user 188 */ 189int 190find_user(const char *name, char *tty) 191{ 192 struct utmpx *ut; 193 int status; 194 struct stat statb; 195 time_t best = 0; 196 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(ut->ut_line)]; 197 198 setutxent(); 199 status = NOT_HERE; 200 (void) strcpy(ftty, _PATH_DEV); 201 while ((ut = getutxent()) != NULL) 202 if (ut->ut_type == USER_PROCESS && 203 strcmp(ut->ut_user, name) == 0) { 204 if (*tty == '\0' || best != 0) { 205 if (best == 0) 206 status = PERMISSION_DENIED; 207 /* no particular tty was requested */ 208 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1, 209 ut->ut_line); 210 if (stat(ftty, &statb) == 0) { 211 if (!(statb.st_mode & 020)) 212 continue; 213 if (statb.st_atime > best) { 214 best = statb.st_atime; 215 (void) strcpy(tty, ut->ut_line); 216 status = SUCCESS; 217 continue; 218 } 219 } 220 } 221 if (strcmp(ut->ut_line, tty) == 0) { 222 status = SUCCESS; 223 break; 224 } 225 } 226 endutxent(); 227 return (status); 228} 229