process.c revision 202210
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 202210 2010-01-13 18:28:58Z 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 66extern int debug; 67 68void 69process_request(CTL_MSG *mp, CTL_RESPONSE *rp) 70{ 71 CTL_MSG *ptr; 72 char *s; 73 74 rp->vers = TALK_VERSION; 75 rp->type = mp->type; 76 rp->id_num = htonl(0); 77 if (mp->vers != TALK_VERSION) { 78 syslog(LOG_WARNING, "bad protocol version %d", mp->vers); 79 rp->answer = BADVERSION; 80 return; 81 } 82 mp->id_num = ntohl(mp->id_num); 83 mp->addr.sa_family = ntohs(mp->addr.sa_family); 84 if (mp->addr.sa_family != AF_INET) { 85 syslog(LOG_WARNING, "bad address, family %d", 86 mp->addr.sa_family); 87 rp->answer = BADADDR; 88 return; 89 } 90 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 91 if (mp->ctl_addr.sa_family != AF_INET) { 92 syslog(LOG_WARNING, "bad control address, family %d", 93 mp->ctl_addr.sa_family); 94 rp->answer = BADCTLADDR; 95 return; 96 } 97 for (s = mp->l_name; *s; s++) 98 if (!isprint(*s)) { 99 syslog(LOG_NOTICE, "illegal user name. Aborting"); 100 rp->answer = FAILED; 101 return; 102 } 103 mp->pid = ntohl(mp->pid); 104 if (debug) 105 print_request("process_request", mp); 106 switch (mp->type) { 107 108 case ANNOUNCE: 109 do_announce(mp, rp); 110 break; 111 112 case LEAVE_INVITE: 113 ptr = find_request(mp); 114 if (ptr != (CTL_MSG *)0) { 115 rp->id_num = htonl(ptr->id_num); 116 rp->answer = SUCCESS; 117 } else 118 insert_table(mp, rp); 119 break; 120 121 case LOOK_UP: 122 ptr = find_match(mp); 123 if (ptr != (CTL_MSG *)0) { 124 rp->id_num = htonl(ptr->id_num); 125 rp->addr = ptr->addr; 126 rp->addr.sa_family = htons(ptr->addr.sa_family); 127 rp->answer = SUCCESS; 128 } else 129 rp->answer = NOT_HERE; 130 break; 131 132 case DELETE: 133 rp->answer = delete_invite(mp->id_num); 134 break; 135 136 default: 137 rp->answer = UNKNOWN_REQUEST; 138 break; 139 } 140 if (debug) 141 print_response("process_request", rp); 142} 143 144void 145do_announce(CTL_MSG *mp, CTL_RESPONSE *rp) 146{ 147 struct hostent *hp; 148 CTL_MSG *ptr; 149 int result; 150 151 /* see if the user is logged */ 152 result = find_user(mp->r_name, mp->r_tty); 153 if (result != SUCCESS) { 154 rp->answer = result; 155 return; 156 } 157#define satosin(sa) ((struct sockaddr_in *)(void *)(sa)) 158 hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr, 159 sizeof (struct in_addr), AF_INET); 160 if (hp == (struct hostent *)0) { 161 rp->answer = MACHINE_UNKNOWN; 162 return; 163 } 164 ptr = find_request(mp); 165 if (ptr == (CTL_MSG *) 0) { 166 insert_table(mp, rp); 167 rp->answer = announce(mp, hp->h_name); 168 return; 169 } 170 if (mp->id_num > ptr->id_num) { 171 /* 172 * This is an explicit re-announce, so update the id_num 173 * field to avoid duplicates and re-announce the talk. 174 */ 175 ptr->id_num = new_id(); 176 rp->id_num = htonl(ptr->id_num); 177 rp->answer = announce(mp, hp->h_name); 178 } else { 179 /* a duplicated request, so ignore it */ 180 rp->id_num = htonl(ptr->id_num); 181 rp->answer = SUCCESS; 182 } 183} 184 185/* 186 * Search utmp for the local user 187 */ 188int 189find_user(const char *name, char *tty) 190{ 191 struct utmpx *ut; 192 int status; 193 struct stat statb; 194 time_t best = 0; 195 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(ut->ut_line)]; 196 197 setutxent(); 198 status = NOT_HERE; 199 (void) strcpy(ftty, _PATH_DEV); 200 while ((ut = getutxent()) != NULL) 201 if (ut->ut_type == USER_PROCESS && 202 strcmp(ut->ut_user, name) == 0) { 203 if (*tty == '\0' || best != 0) { 204 if (best == 0) 205 status = PERMISSION_DENIED; 206 /* no particular tty was requested */ 207 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1, 208 ut->ut_line); 209 if (stat(ftty, &statb) == 0) { 210 if (!(statb.st_mode & 020)) 211 continue; 212 if (statb.st_atime > best) { 213 best = statb.st_atime; 214 (void) strcpy(tty, ut->ut_line); 215 status = SUCCESS; 216 continue; 217 } 218 } 219 } 220 if (strcmp(ut->ut_line, tty) == 0) { 221 status = SUCCESS; 222 break; 223 } 224 } 225 endutxent(); 226 return (status); 227} 228