1 /* $OpenBSD: table.c,v 1.10 2003/06/11 14:24:46 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1983 Regents of the University of California. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #ifndef lint 33 /*static char sccsid[] = "from: @(#)table.c 5.7 (Berkeley) 2/26/91";*/ 34 static char rcsid[] = "$Id: table.c,v 1.10 2003/06/11 14:24:46 deraadt Exp $"; 35 #endif /* not lint */ 36 37 /* 38 * Routines to handle insertion, deletion, etc on the table 39 * of requests kept by the daemon. Nothing fancy here, linear 40 * search on a double-linked list. A time is kept with each 41 * entry so that overly old invitations can be eliminated. 42 * 43 * Consider this a mis-guided attempt at modularity 44 */ 45 #include <sys/param.h> 46 #include <sys/time.h> 47 #include <sys/socket.h> 48 #include <sys/queue.h> 49 #include <protocols/talkd.h> 50 #include <syslog.h> 51 #include <unistd.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include "talkd.h" 56 57 #define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */ 58 59 struct timeval tp; 60 struct timezone txp; 61 62 typedef struct table_entry TABLE_ENTRY; 63 64 struct table_entry { 65 CTL_MSG request; 66 time_t time; 67 TAILQ_ENTRY(table_entry) list; 68 }; 69 TAILQ_HEAD(, table_entry) table; 70 71 static void delete(TABLE_ENTRY *); 72 73 /* 74 * Init the table 75 */ 76 void 77 init_table(void) 78 { 79 TAILQ_INIT(&table); 80 } 81 82 /* 83 * Look in the table for an invitation that matches the current 84 * request looking for an invitation 85 */ 86 CTL_MSG * 87 find_match(CTL_MSG *request) 88 { 89 TABLE_ENTRY *ptr; 90 time_t current_time; 91 92 gettimeofday(&tp, &txp); 93 current_time = tp.tv_sec; 94 if (debug) 95 print_request("find_match", request); 96 for (ptr = table.tqh_first; ptr != NULL; ptr = ptr->list.tqe_next) { 97 if ((current_time - ptr->time) > MAX_LIFE) { 98 /* the entry is too old */ 99 if (debug) 100 print_request("deleting expired entry", 101 &ptr->request); 102 delete(ptr); 103 continue; 104 } 105 if (debug) 106 print_request("", &ptr->request); 107 if (strcmp(request->l_name, ptr->request.r_name) == 0 && 108 strcmp(request->r_name, ptr->request.l_name) == 0 && 109 ptr->request.type == LEAVE_INVITE) 110 return (&ptr->request); 111 } 112 if (debug) 113 syslog(LOG_DEBUG, "find_match: not found"); 114 115 return ((CTL_MSG *)0); 116 } 117 118 /* 119 * Look for an identical request, as opposed to a complimentary 120 * one as find_match does 121 */ 122 CTL_MSG * 123 find_request(CTL_MSG *request) 124 { 125 TABLE_ENTRY *ptr; 126 time_t current_time; 127 128 gettimeofday(&tp, &txp); 129 current_time = tp.tv_sec; 130 /* 131 * See if this is a repeated message, and check for 132 * out of date entries in the table while we are it. 133 */ 134 if (debug) 135 print_request("find_request", request); 136 for (ptr = table.tqh_first; ptr != NULL; ptr = ptr->list.tqe_next) { 137 if ((current_time - ptr->time) > MAX_LIFE) { 138 /* the entry is too old */ 139 if (debug) 140 print_request("deleting expired entry", 141 &ptr->request); 142 delete(ptr); 143 continue; 144 } 145 if (debug) 146 print_request("", &ptr->request); 147 if (strcmp(request->r_name, ptr->request.r_name) == 0 && 148 strcmp(request->l_name, ptr->request.l_name) == 0 && 149 request->type == ptr->request.type && 150 request->pid == ptr->request.pid) { 151 /* update the time if we 'touch' it */ 152 ptr->time = current_time; 153 return (&ptr->request); 154 } 155 } 156 return ((CTL_MSG *)0); 157 } 158 159 void 160 insert_table(CTL_MSG *request, CTL_RESPONSE *response) 161 { 162 TABLE_ENTRY *ptr; 163 time_t current_time; 164 165 if (debug) 166 print_request( "insert_table", request ); 167 gettimeofday(&tp, &txp); 168 current_time = tp.tv_sec; 169 request->id_num = new_id(); 170 response->id_num = htonl(request->id_num); 171 /* insert a new entry into the top of the list */ 172 ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY)); 173 if (ptr == NULL) { 174 syslog(LOG_ERR, "insert_table: Out of memory"); 175 _exit(1); 176 } 177 ptr->time = current_time; 178 ptr->request = *request; 179 TAILQ_INSERT_HEAD(&table, ptr, list); 180 } 181 182 /* 183 * Generate a unique non-zero sequence number 184 */ 185 int 186 new_id(void) 187 { 188 static int current_id = 0; 189 190 current_id = (current_id + 1) % MAX_ID; 191 /* 0 is reserved, helps to pick up bugs */ 192 if (current_id == 0) 193 current_id = 1; 194 return (current_id); 195 } 196 197 /* 198 * Delete the invitation with id 'id_num' 199 */ 200 int 201 delete_invite(int id_num) 202 { 203 TABLE_ENTRY *ptr; 204 205 if (debug) 206 syslog(LOG_DEBUG, "delete_invite(%d)", id_num); 207 for (ptr = table.tqh_first; ptr != NULL; ptr = ptr->list.tqe_next) { 208 if (ptr->request.id_num == id_num) 209 break; 210 if (debug) 211 print_request("", &ptr->request); 212 } 213 if (ptr != NULL) { 214 delete(ptr); 215 return (SUCCESS); 216 } 217 return (NOT_HERE); 218 } 219 220 /* 221 * Classic delete from a double-linked list 222 */ 223 static void 224 delete(TABLE_ENTRY *ptr) 225 { 226 227 if (debug) 228 print_request("delete", &ptr->request); 229 TAILQ_REMOVE(&table, ptr, list); 230 free((char *)ptr); 231 } 232