process.c revision 241777
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 241777 2012-10-20 10:33:15Z 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#include <utmpx.h> 63 64#include "extern.h" 65 66void 67process_request(CTL_MSG *mp, CTL_RESPONSE *rp) 68{ 69 CTL_MSG *ptr; 70 char *s; 71 72 rp->vers = TALK_VERSION; 73 rp->type = mp->type; 74 rp->id_num = htonl(0); 75 if (mp->vers != TALK_VERSION) { 76 syslog(LOG_WARNING, "bad protocol version %d", mp->vers); 77 rp->answer = BADVERSION; 78 return; 79 } 80 mp->id_num = ntohl(mp->id_num); 81 mp->addr.sa_family = ntohs(mp->addr.sa_family); 82 if (mp->addr.sa_family != AF_INET) { 83 syslog(LOG_WARNING, "bad address, family %d", 84 mp->addr.sa_family); 85 rp->answer = BADADDR; 86 return; 87 } 88 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 89 if (mp->ctl_addr.sa_family != AF_INET) { 90 syslog(LOG_WARNING, "bad control address, family %d", 91 mp->ctl_addr.sa_family); 92 rp->answer = BADCTLADDR; 93 return; 94 } 95 for (s = mp->l_name; *s; s++) 96 if (!isprint(*s)) { 97 syslog(LOG_NOTICE, "illegal user name. Aborting"); 98 rp->answer = FAILED; 99 return; 100 } 101 mp->pid = ntohl(mp->pid); 102 if (debug) 103 print_request("process_request", mp); 104 switch (mp->type) { 105 106 case ANNOUNCE: 107 do_announce(mp, rp); 108 break; 109 110 case LEAVE_INVITE: 111 ptr = find_request(mp); 112 if (ptr != (CTL_MSG *)0) { 113 rp->id_num = htonl(ptr->id_num); 114 rp->answer = SUCCESS; 115 } else 116 insert_table(mp, rp); 117 break; 118 119 case LOOK_UP: 120 ptr = find_match(mp); 121 if (ptr != (CTL_MSG *)0) { 122 rp->id_num = htonl(ptr->id_num); 123 rp->addr = ptr->addr; 124 rp->addr.sa_family = htons(ptr->addr.sa_family); 125 rp->answer = SUCCESS; 126 } else 127 rp->answer = NOT_HERE; 128 break; 129 130 case DELETE: 131 rp->answer = delete_invite(mp->id_num); 132 break; 133 134 default: 135 rp->answer = UNKNOWN_REQUEST; 136 break; 137 } 138 if (debug) 139 print_response("process_request", rp); 140} 141 142void 143do_announce(CTL_MSG *mp, 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 *)(void *)(sa)) 156 hp = gethostbyaddr(&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/* 184 * Search utmp for the local user 185 */ 186int 187find_user(const char *name, char *tty) 188{ 189 struct utmpx *ut; 190 int status; 191 struct stat statb; 192 time_t best = 0; 193 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(ut->ut_line)]; 194 195 setutxent(); 196 status = NOT_HERE; 197 (void) strcpy(ftty, _PATH_DEV); 198 while ((ut = getutxent()) != NULL) 199 if (ut->ut_type == USER_PROCESS && 200 strcmp(ut->ut_user, name) == 0) { 201 if (*tty == '\0' || best != 0) { 202 if (best == 0) 203 status = PERMISSION_DENIED; 204 /* no particular tty was requested */ 205 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1, 206 ut->ut_line); 207 if (stat(ftty, &statb) == 0) { 208 if (!(statb.st_mode & 020)) 209 continue; 210 if (statb.st_atime > best) { 211 best = statb.st_atime; 212 (void) strcpy(tty, ut->ut_line); 213 status = SUCCESS; 214 continue; 215 } 216 } 217 } 218 if (strcmp(ut->ut_line, tty) == 0) { 219 status = SUCCESS; 220 break; 221 } 222 } 223 endutxent(); 224 return (status); 225} 226