1 /* 2 * Copyright (c) 1983 Regents of the University of California. 3 * 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 /*static char sccsid[] = "from: @(#)table.c 5.7 (Berkeley) 2/26/91";*/ 36 static char rcsid[] = "$Id: table.c,v 1.2 1993/08/01 18:29:32 mycroft Exp $"; 37 #endif /* not lint */ 38 39 /* 40 * Routines to handle insertion, deletion, etc on the table 41 * of requests kept by the daemon. Nothing fancy here, linear 42 * search on a double-linked list. A time is kept with each 43 * entry so that overly old invitations can be eliminated. 44 * 45 * Consider this a mis-guided attempt at modularity 46 */ 47 #include <sys/param.h> 48 #include <sys/time.h> 49 #include <sys/socket.h> 50 #include <protocols/talkd.h> 51 #include <syslog.h> 52 #include <unistd.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 57 #define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */ 58 59 #define NIL ((TABLE_ENTRY *)0) 60 61 extern int debug; 62 struct timeval tp; 63 struct timezone txp; 64 65 typedef struct table_entry TABLE_ENTRY; 66 67 struct table_entry { 68 CTL_MSG request; 69 long time; 70 TABLE_ENTRY *next; 71 TABLE_ENTRY *last; 72 }; 73 74 TABLE_ENTRY *table = NIL; 75 CTL_MSG *find_request(); 76 CTL_MSG *find_match(); 77 78 /* 79 * Look in the table for an invitation that matches the current 80 * request looking for an invitation 81 */ 82 CTL_MSG * 83 find_match(request) 84 register CTL_MSG *request; 85 { 86 register TABLE_ENTRY *ptr; 87 time_t current_time; 88 89 gettimeofday(&tp, &txp); 90 current_time = tp.tv_sec; 91 if (debug) 92 print_request("find_match", request); 93 for (ptr = table; ptr != NIL; ptr = ptr->next) { 94 if ((ptr->time - current_time) > MAX_LIFE) { 95 /* the entry is too old */ 96 if (debug) 97 print_request("deleting expired entry", 98 &ptr->request); 99 delete(ptr); 100 continue; 101 } 102 if (debug) 103 print_request("", &ptr->request); 104 if (strcmp(request->l_name, ptr->request.r_name) == 0 && 105 strcmp(request->r_name, ptr->request.l_name) == 0 && 106 ptr->request.type == LEAVE_INVITE) 107 return (&ptr->request); 108 } 109 return ((CTL_MSG *)0); 110 } 111 112 /* 113 * Look for an identical request, as opposed to a complimentary 114 * one as find_match does 115 */ 116 CTL_MSG * 117 find_request(request) 118 register CTL_MSG *request; 119 { 120 register TABLE_ENTRY *ptr; 121 time_t current_time; 122 123 gettimeofday(&tp, &txp); 124 current_time = tp.tv_sec; 125 /* 126 * See if this is a repeated message, and check for 127 * out of date entries in the table while we are it. 128 */ 129 if (debug) 130 print_request("find_request", request); 131 for (ptr = table; ptr != NIL; ptr = ptr->next) { 132 if ((ptr->time - current_time) > MAX_LIFE) { 133 /* the entry is too old */ 134 if (debug) 135 print_request("deleting expired entry", 136 &ptr->request); 137 delete(ptr); 138 continue; 139 } 140 if (debug) 141 print_request("", &ptr->request); 142 if (strcmp(request->r_name, ptr->request.r_name) == 0 && 143 strcmp(request->l_name, ptr->request.l_name) == 0 && 144 request->type == ptr->request.type && 145 request->pid == ptr->request.pid) { 146 /* update the time if we 'touch' it */ 147 ptr->time = current_time; 148 return (&ptr->request); 149 } 150 } 151 return ((CTL_MSG *)0); 152 } 153 154 insert_table(request, response) 155 CTL_MSG *request; 156 CTL_RESPONSE *response; 157 { 158 register TABLE_ENTRY *ptr; 159 time_t current_time; 160 161 gettimeofday(&tp, &txp); 162 current_time = tp.tv_sec; 163 request->id_num = new_id(); 164 response->id_num = htonl(request->id_num); 165 /* insert a new entry into the top of the list */ 166 ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY)); 167 if (ptr == NIL) { 168 syslog(LOG_ERR, "insert_table: Out of memory"); 169 _exit(1); 170 } 171 ptr->time = current_time; 172 ptr->request = *request; 173 ptr->next = table; 174 if (ptr->next != NIL) 175 ptr->next->last = ptr; 176 ptr->last = NIL; 177 table = ptr; 178 } 179 180 /* 181 * Generate a unique non-zero sequence number 182 */ 183 new_id() 184 { 185 static int current_id = 0; 186 187 current_id = (current_id + 1) % MAX_ID; 188 /* 0 is reserved, helps to pick up bugs */ 189 if (current_id == 0) 190 current_id = 1; 191 return (current_id); 192 } 193 194 /* 195 * Delete the invitation with id 'id_num' 196 */ 197 delete_invite(id_num) 198 int id_num; 199 { 200 register TABLE_ENTRY *ptr; 201 202 ptr = table; 203 if (debug) 204 syslog(LOG_DEBUG, "delete_invite(%d)", id_num); 205 for (ptr = table; ptr != NIL; ptr = ptr->next) { 206 if (ptr->request.id_num == id_num) 207 break; 208 if (debug) 209 print_request("", &ptr->request); 210 } 211 if (ptr != NIL) { 212 delete(ptr); 213 return (SUCCESS); 214 } 215 return (NOT_HERE); 216 } 217 218 /* 219 * Classic delete from a double-linked list 220 */ 221 delete(ptr) 222 register TABLE_ENTRY *ptr; 223 { 224 225 if (debug) 226 print_request("delete", &ptr->request); 227 if (table == ptr) 228 table = ptr->next; 229 else if (ptr->last != NIL) 230 ptr->last->next = ptr->next; 231 if (ptr->next != NIL) 232 ptr->next->last = ptr->last; 233 free((char *)ptr); 234 } 235