table.c revision 112998
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[] = "@(#)table.c 8.1 (Berkeley) 6/4/93"; 37#endif 38static const char rcsid[] = 39 "$FreeBSD: head/libexec/talkd/table.c 112998 2003-04-03 05:13:27Z jmallett $"; 40#endif /* not lint */ 41 42/* 43 * Routines to handle insertion, deletion, etc on the table 44 * of requests kept by the daemon. Nothing fancy here, linear 45 * search on a double-linked list. A time is kept with each 46 * entry so that overly old invitations can be eliminated. 47 * 48 * Consider this a mis-guided attempt at modularity 49 */ 50#include <sys/param.h> 51#include <sys/time.h> 52#include <sys/socket.h> 53#include <netinet/in.h> 54#include <protocols/talkd.h> 55#include <stdio.h> 56#include <stdlib.h> 57#include <string.h> 58#include <syslog.h> 59#include <unistd.h> 60 61#include "extern.h" 62 63#define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */ 64 65#define NIL ((TABLE_ENTRY *)0) 66 67extern int debug; 68struct timeval tp; 69struct timezone txp; 70 71typedef struct table_entry TABLE_ENTRY; 72 73struct table_entry { 74 CTL_MSG request; 75 long time; 76 TABLE_ENTRY *next; 77 TABLE_ENTRY *last; 78}; 79 80static void delete(TABLE_ENTRY *); 81 82TABLE_ENTRY *table = NIL; 83 84/* 85 * Look in the table for an invitation that matches the current 86 * request looking for an invitation 87 */ 88CTL_MSG * 89find_match(CTL_MSG *request) 90{ 91 TABLE_ENTRY *ptr; 92 time_t current_time; 93 94 gettimeofday(&tp, &txp); 95 current_time = tp.tv_sec; 96 if (debug) 97 print_request("find_match", request); 98 for (ptr = table; ptr != NIL; ptr = ptr->next) { 99 if ((ptr->time - current_time) > MAX_LIFE) { 100 /* the entry is too old */ 101 if (debug) 102 print_request("deleting expired entry", 103 &ptr->request); 104 delete(ptr); 105 continue; 106 } 107 if (debug) 108 print_request("", &ptr->request); 109 if (strcmp(request->l_name, ptr->request.r_name) == 0 && 110 strcmp(request->r_name, ptr->request.l_name) == 0 && 111 ptr->request.type == LEAVE_INVITE) 112 return (&ptr->request); 113 } 114 return ((CTL_MSG *)0); 115} 116 117/* 118 * Look for an identical request, as opposed to a complimentary 119 * one as find_match does 120 */ 121CTL_MSG * 122find_request(CTL_MSG *request) 123{ 124 TABLE_ENTRY *ptr; 125 time_t current_time; 126 127 gettimeofday(&tp, &txp); 128 current_time = tp.tv_sec; 129 /* 130 * See if this is a repeated message, and check for 131 * out of date entries in the table while we are it. 132 */ 133 if (debug) 134 print_request("find_request", request); 135 for (ptr = table; ptr != NIL; ptr = ptr->next) { 136 if ((ptr->time - current_time) > MAX_LIFE) { 137 /* the entry is too old */ 138 if (debug) 139 print_request("deleting expired entry", 140 &ptr->request); 141 delete(ptr); 142 continue; 143 } 144 if (debug) 145 print_request("", &ptr->request); 146 if (strcmp(request->r_name, ptr->request.r_name) == 0 && 147 strcmp(request->l_name, ptr->request.l_name) == 0 && 148 request->type == ptr->request.type && 149 request->pid == ptr->request.pid) { 150 /* update the time if we 'touch' it */ 151 ptr->time = current_time; 152 return (&ptr->request); 153 } 154 } 155 return ((CTL_MSG *)0); 156} 157 158void 159insert_table(CTL_MSG *request, CTL_RESPONSE *response) 160{ 161 TABLE_ENTRY *ptr; 162 time_t current_time; 163 164 gettimeofday(&tp, &txp); 165 current_time = tp.tv_sec; 166 request->id_num = new_id(); 167 response->id_num = htonl(request->id_num); 168 /* insert a new entry into the top of the list */ 169 ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY)); 170 if (ptr == NIL) { 171 syslog(LOG_ERR, "insert_table: Out of memory"); 172 _exit(1); 173 } 174 ptr->time = current_time; 175 ptr->request = *request; 176 ptr->next = table; 177 if (ptr->next != NIL) 178 ptr->next->last = ptr; 179 ptr->last = NIL; 180 table = ptr; 181} 182 183/* 184 * Generate a unique non-zero sequence number 185 */ 186int 187new_id(void) 188{ 189 static int current_id = 0; 190 191 current_id = (current_id + 1) % MAX_ID; 192 /* 0 is reserved, helps to pick up bugs */ 193 if (current_id == 0) 194 current_id = 1; 195 return (current_id); 196} 197 198/* 199 * Delete the invitation with id 'id_num' 200 */ 201int 202delete_invite(u_int32_t 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 */ 225static void 226delete(TABLE_ENTRY *ptr) 227{ 228 229 if (debug) 230 print_request("delete", &ptr->request); 231 if (table == ptr) 232 table = ptr->next; 233 else if (ptr->last != NIL) 234 ptr->last->next = ptr->next; 235 if (ptr->next != NIL) 236 ptr->next->last = ptr->last; 237 free((char *)ptr); 238} 239