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 * @(#)table.c 8.1 (Berkeley) 6/4/93 34 * $FreeBSD: src/libexec/talkd/table.c,v 1.7 1999/08/28 00:10:17 peter Exp $ 35 * $DragonFly: src/libexec/talkd/table.c,v 1.3 2003/11/14 03:54:31 dillon Exp $ 36 */ 37 38 /* 39 * Routines to handle insertion, deletion, etc on the table 40 * of requests kept by the daemon. Nothing fancy here, linear 41 * search on a double-linked list. A time is kept with each 42 * entry so that overly old invitations can be eliminated. 43 * 44 * Consider this a mis-guided attempt at modularity 45 */ 46 #include <sys/param.h> 47 #include <sys/time.h> 48 #include <sys/socket.h> 49 #include <protocols/talkd.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <syslog.h> 54 #include <unistd.h> 55 56 #define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */ 57 58 #define NIL ((TABLE_ENTRY *)0) 59 60 extern int debug; 61 struct timeval tp; 62 struct timezone txp; 63 64 typedef struct table_entry TABLE_ENTRY; 65 66 struct table_entry { 67 CTL_MSG request; 68 long time; 69 TABLE_ENTRY *next; 70 TABLE_ENTRY *last; 71 }; 72 73 TABLE_ENTRY *table = NIL; 74 75 void delete (TABLE_ENTRY *); 76 CTL_MSG *find_request(); 77 CTL_MSG *find_match(); 78 int new_id (void); 79 void print_request (char *, CTL_MSG *); 80 81 /* 82 * Look in the table for an invitation that matches the current 83 * request looking for an invitation 84 */ 85 CTL_MSG * 86 find_match(request) 87 register CTL_MSG *request; 88 { 89 register 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; ptr != NIL; ptr = ptr->next) { 97 if ((ptr->time - current_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 return ((CTL_MSG *)0); 113 } 114 115 /* 116 * Look for an identical request, as opposed to a complimentary 117 * one as find_match does 118 */ 119 CTL_MSG * 120 find_request(request) 121 register CTL_MSG *request; 122 { 123 register TABLE_ENTRY *ptr; 124 time_t current_time; 125 126 gettimeofday(&tp, &txp); 127 current_time = tp.tv_sec; 128 /* 129 * See if this is a repeated message, and check for 130 * out of date entries in the table while we are it. 131 */ 132 if (debug) 133 print_request("find_request", request); 134 for (ptr = table; ptr != NIL; ptr = ptr->next) { 135 if ((ptr->time - current_time) > MAX_LIFE) { 136 /* the entry is too old */ 137 if (debug) 138 print_request("deleting expired entry", 139 &ptr->request); 140 delete(ptr); 141 continue; 142 } 143 if (debug) 144 print_request("", &ptr->request); 145 if (strcmp(request->r_name, ptr->request.r_name) == 0 && 146 strcmp(request->l_name, ptr->request.l_name) == 0 && 147 request->type == ptr->request.type && 148 request->pid == ptr->request.pid) { 149 /* update the time if we 'touch' it */ 150 ptr->time = current_time; 151 return (&ptr->request); 152 } 153 } 154 return ((CTL_MSG *)0); 155 } 156 157 void 158 insert_table(request, response) 159 CTL_MSG *request; 160 CTL_RESPONSE *response; 161 { 162 register TABLE_ENTRY *ptr; 163 time_t current_time; 164 165 gettimeofday(&tp, &txp); 166 current_time = tp.tv_sec; 167 request->id_num = new_id(); 168 response->id_num = htonl(request->id_num); 169 /* insert a new entry into the top of the list */ 170 ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY)); 171 if (ptr == NIL) { 172 syslog(LOG_ERR, "insert_table: Out of memory"); 173 _exit(1); 174 } 175 ptr->time = current_time; 176 ptr->request = *request; 177 ptr->next = table; 178 if (ptr->next != NIL) 179 ptr->next->last = ptr; 180 ptr->last = NIL; 181 table = ptr; 182 } 183 184 /* 185 * Generate a unique non-zero sequence number 186 */ 187 int 188 new_id() 189 { 190 static int current_id = 0; 191 192 current_id = (current_id + 1) % MAX_ID; 193 /* 0 is reserved, helps to pick up bugs */ 194 if (current_id == 0) 195 current_id = 1; 196 return (current_id); 197 } 198 199 /* 200 * Delete the invitation with id 'id_num' 201 */ 202 int 203 delete_invite(id_num) 204 int id_num; 205 { 206 register TABLE_ENTRY *ptr; 207 208 ptr = table; 209 if (debug) 210 syslog(LOG_DEBUG, "delete_invite(%d)", id_num); 211 for (ptr = table; ptr != NIL; ptr = ptr->next) { 212 if (ptr->request.id_num == id_num) 213 break; 214 if (debug) 215 print_request("", &ptr->request); 216 } 217 if (ptr != NIL) { 218 delete(ptr); 219 return (SUCCESS); 220 } 221 return (NOT_HERE); 222 } 223 224 /* 225 * Classic delete from a double-linked list 226 */ 227 void 228 delete(ptr) 229 register TABLE_ENTRY *ptr; 230 { 231 232 if (debug) 233 print_request("delete", &ptr->request); 234 if (table == ptr) 235 table = ptr->next; 236 else if (ptr->last != NIL) 237 ptr->last->next = ptr->next; 238 if (ptr->next != NIL) 239 ptr->next->last = ptr->last; 240 free((char *)ptr); 241 } 242