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 extern int debug; 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 long time; 67 TABLE_ENTRY *next; 68 TABLE_ENTRY *last; 69 }; 70 71 TABLE_ENTRY *table = NULL; 72 73 void delete (TABLE_ENTRY *); 74 CTL_MSG *find_request(); 75 CTL_MSG *find_match(); 76 int new_id (void); 77 void print_request (char *, CTL_MSG *); 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 register CTL_MSG *request; 86 { 87 register TABLE_ENTRY *ptr; 88 time_t current_time; 89 90 gettimeofday(&tp, &txp); 91 current_time = tp.tv_sec; 92 if (debug) 93 print_request("find_match", request); 94 for (ptr = table; ptr != NULL; 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 (NULL); 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 register CTL_MSG *request; 120 { 121 register TABLE_ENTRY *ptr; 122 time_t current_time; 123 124 gettimeofday(&tp, &txp); 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 != NULL; 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 (NULL); 153 } 154 155 void 156 insert_table(request, response) 157 CTL_MSG *request; 158 CTL_RESPONSE *response; 159 { 160 register TABLE_ENTRY *ptr; 161 time_t current_time; 162 163 gettimeofday(&tp, &txp); 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 == NULL) { 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 != NULL) 177 ptr->next->last = ptr; 178 ptr->last = NULL; 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 register TABLE_ENTRY *ptr; 205 206 ptr = table; 207 if (debug) 208 syslog(LOG_DEBUG, "delete_invite(%d)", id_num); 209 for (ptr = table; ptr != NULL; 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 != NULL) { 216 delete(ptr); 217 return (SUCCESS); 218 } 219 return (NOT_HERE); 220 } 221 222 /* 223 * Classic delete from a double-linked list 224 */ 225 void 226 delete(ptr) 227 register 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 != NULL) 235 ptr->last->next = ptr->next; 236 if (ptr->next != NULL) 237 ptr->next->last = ptr->last; 238 free((char *)ptr); 239 } 240