1 /* $NetBSD: table.c,v 1.8 2008/03/04 03:05:00 dholland Exp $ */ 2 3 /* 4 * Copyright (c) 1983, 1993 5 * The Regents of the University of California. 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 #include <sys/cdefs.h> 33 #ifndef lint 34 #if 0 35 static char sccsid[] = "@(#)table.c 8.1 (Berkeley) 6/4/93"; 36 #else 37 __RCSID("$NetBSD: table.c,v 1.8 2008/03/04 03:05:00 dholland Exp $"); 38 #endif 39 #endif /* not lint */ 40 41 /* 42 * Routines to handle insertion, deletion, etc on the table 43 * of requests kept by the daemon. Nothing fancy here, linear 44 * search on a double-linked list. A time is kept with each 45 * entry so that overly old invitations can be eliminated. 46 * 47 * Consider this a mis-guided attempt at modularity 48 */ 49 #include <sys/param.h> 50 #include <sys/time.h> 51 #include <sys/socket.h> 52 #include <protocols/talkd.h> 53 #include <syslog.h> 54 #include <unistd.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include "extern.h" 59 60 #define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */ 61 62 #define NIL ((TABLE_ENTRY *)0) 63 64 struct timeval tp; 65 66 typedef struct table_entry TABLE_ENTRY; 67 68 struct table_entry { 69 CTL_MSG request; 70 time_t time; 71 TABLE_ENTRY *next; 72 TABLE_ENTRY *last; 73 }; 74 75 TABLE_ENTRY *table = NIL; 76 77 static void delete __P((TABLE_ENTRY *)); 78 79 /* 80 * Look in the table for an invitation that matches the current 81 * request looking for an invitation 82 */ 83 CTL_MSG * 84 find_match(request) 85 CTL_MSG *request; 86 { 87 TABLE_ENTRY *ptr; 88 time_t current_time; 89 90 gettimeofday(&tp, NULL); 91 current_time = tp.tv_sec; 92 if (debug) 93 print_request("find_match", request); 94 for (ptr = table; ptr != NIL; ptr = ptr->next) { 95 if ((ptr->time - current_time) > MAX_LIFE) { 96 /* the entry is too old */ 97 if (debug) 98 print_request("deleting expired entry", 99 &ptr->request); 100 delete(ptr); 101 continue; 102 } 103 if (debug) 104 print_request("", &ptr->request); 105 if (strcmp(request->l_name, ptr->request.r_name) == 0 && 106 strcmp(request->r_name, ptr->request.l_name) == 0 && 107 ptr->request.type == LEAVE_INVITE) 108 return (&ptr->request); 109 } 110 return ((CTL_MSG *)0); 111 } 112 113 /* 114 * Look for an identical request, as opposed to a complimentary 115 * one as find_match does 116 */ 117 CTL_MSG * 118 find_request(request) 119 CTL_MSG *request; 120 { 121 TABLE_ENTRY *ptr; 122 time_t current_time; 123 124 gettimeofday(&tp, NULL); 125 current_time = tp.tv_sec; 126 /* 127 * See if this is a repeated message, and check for 128 * out of date entries in the table while we are it. 129 */ 130 if (debug) 131 print_request("find_request", request); 132 for (ptr = table; ptr != NIL; ptr = ptr->next) { 133 if ((ptr->time - current_time) > MAX_LIFE) { 134 /* the entry is too old */ 135 if (debug) 136 print_request("deleting expired entry", 137 &ptr->request); 138 delete(ptr); 139 continue; 140 } 141 if (debug) 142 print_request("", &ptr->request); 143 if (strcmp(request->r_name, ptr->request.r_name) == 0 && 144 strcmp(request->l_name, ptr->request.l_name) == 0 && 145 request->type == ptr->request.type && 146 request->pid == ptr->request.pid) { 147 /* update the time if we 'touch' it */ 148 ptr->time = current_time; 149 return (&ptr->request); 150 } 151 } 152 return ((CTL_MSG *)0); 153 } 154 155 void 156 insert_table(request, response) 157 CTL_MSG *request; 158 CTL_RESPONSE *response; 159 { 160 TABLE_ENTRY *ptr; 161 time_t current_time; 162 163 gettimeofday(&tp, NULL); 164 current_time = tp.tv_sec; 165 request->id_num = new_id(); 166 response->id_num = htonl(request->id_num); 167 /* insert a new entry into the top of the list */ 168 ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY)); 169 if (ptr == NIL) { 170 syslog(LOG_ERR, "insert_table: Out of memory"); 171 _exit(1); 172 } 173 ptr->time = current_time; 174 ptr->request = *request; 175 ptr->next = table; 176 if (ptr->next != NIL) 177 ptr->next->last = ptr; 178 ptr->last = NIL; 179 table = ptr; 180 } 181 182 /* 183 * Generate a unique non-zero sequence number 184 */ 185 int 186 new_id() 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(id_num) 202 int id_num; 203 { 204 TABLE_ENTRY *ptr; 205 206 ptr = table; 207 if (debug) 208 syslog(LOG_DEBUG, "delete_invite(%d)", id_num); 209 for (ptr = table; ptr != NIL; ptr = ptr->next) { 210 if (ptr->request.id_num == id_num) 211 break; 212 if (debug) 213 print_request("", &ptr->request); 214 } 215 if (ptr != NIL) { 216 delete(ptr); 217 return (SUCCESS); 218 } 219 return (NOT_HERE); 220 } 221 222 /* 223 * Classic delete from a double-linked list 224 */ 225 static void 226 delete(ptr) 227 TABLE_ENTRY *ptr; 228 { 229 230 if (debug) 231 print_request("delete", &ptr->request); 232 if (table == ptr) 233 table = ptr->next; 234 else if (ptr->last != NIL) 235 ptr->last->next = ptr->next; 236 if (ptr->next != NIL) 237 ptr->next->last = ptr->last; 238 free((char *)ptr); 239 } 240