1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 *
22 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /*
27 * Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T
28 * All Rights Reserved.
29 */
30
31 /*
32 * University Copyright- Copyright (c) 1982, 1986, 1988
33 * The Regents of the University of California.
34 * All Rights Reserved.
35 *
36 * University Acknowledgment- Portions of this document are derived from
37 * software developed by the University of California, Berkeley, and its
38 * contributors.
39 */
40
41 #pragma ident "%Z%%M% %I% %E% SMI"
42
43
44 /*
45 * Routines to handle insertion, deletion, etc on the table
46 * of requests kept by the daemon. Nothing fancy here, linear
47 * search on a double-linked list. A time is kept with each
48 * entry so that overly old invitations can be eliminated.
49 *
50 * Consider this a mis-guided attempt at modularity
51 */
52
53 #include <sys/time.h>
54 #include <string.h>
55 #include <stdio.h>
56 #include <malloc.h>
57 #include "talkd_impl.h"
58
59 #define MAX_ID 16000 /* << 2^15 so I don't have sign troubles */
60
61 typedef struct table_entry TABLE_ENTRY;
62
63 struct table_entry {
64 CTL_MSG request;
65 long time;
66 TABLE_ENTRY *next;
67 TABLE_ENTRY *last;
68 };
69
70 static struct timeval tp;
71 static TABLE_ENTRY *table = NULL;
72
73 static void delete(TABLE_ENTRY *ptr);
74
75 /*
76 * Look in the table for an invitation that matches the current
77 * request looking for an invitation.
78 */
79
80 CTL_MSG *
find_match(CTL_MSG * request)81 find_match(CTL_MSG *request)
82 {
83 TABLE_ENTRY *ptr;
84 TABLE_ENTRY *prevp;
85 long current_time;
86
87 (void) gettimeofday(&tp, NULL);
88 current_time = tp.tv_sec;
89
90 ptr = table;
91
92 if (debug) {
93 (void) printf("Entering Look-Up with : \n");
94 print_request(request);
95 }
96
97 while (ptr != NULL) {
98
99 if ((ptr->time - current_time) > MAX_LIFE) {
100 /* the entry is too old */
101 if (debug) {
102 (void) printf("Deleting expired entry : \n");
103 print_request(&ptr->request);
104 }
105 prevp = ptr;
106 ptr = ptr->next;
107 delete(prevp);
108 continue;
109 }
110
111 if (debug)
112 print_request(&ptr->request);
113
114 if (strcmp(request->l_name, ptr->request.r_name) == 0 &&
115 strcmp(request->r_name, ptr->request.l_name) == 0 &&
116 ptr->request.type == LEAVE_INVITE) {
117 return (&ptr->request);
118 }
119
120 ptr = ptr->next;
121 }
122
123 return (NULL);
124 }
125
126 /*
127 * Look for an identical request, as opposed to a complimentary
128 * one as find_match does.
129 */
130
131 CTL_MSG *
find_request(CTL_MSG * request)132 find_request(CTL_MSG *request)
133 {
134 TABLE_ENTRY *ptr;
135 TABLE_ENTRY *prevp;
136 long current_time;
137
138 (void) gettimeofday(&tp, NULL);
139 current_time = tp.tv_sec;
140
141 /*
142 * See if this is a repeated message, and check for
143 * out of date entries in the table while we are it.
144 */
145
146 ptr = table;
147
148 if (debug) {
149 (void) printf("Entering find_request with : \n");
150 print_request(request);
151 }
152
153 while (ptr != NULL) {
154
155 if ((ptr->time - current_time) > MAX_LIFE) {
156 /* the entry is too old */
157 if (debug) {
158 (void) printf("Deleting expired entry : \n");
159 print_request(&ptr->request);
160 }
161 prevp = ptr;
162 ptr = ptr->next;
163 delete(prevp);
164 continue;
165 }
166
167 if (debug)
168 print_request(&ptr->request);
169
170 if (strcmp(request->r_name, ptr->request.r_name) == 0 &&
171 strcmp(request->l_name, ptr->request.l_name) == 0 &&
172 request->type == ptr->request.type &&
173 request->pid == ptr->request.pid) {
174
175 /* update the time if we 'touch' it */
176 ptr->time = current_time;
177 return (&ptr->request);
178 }
179
180 ptr = ptr->next;
181 }
182
183 return (NULL);
184 }
185
186 void
insert_table(CTL_MSG * request,CTL_RESPONSE * response)187 insert_table(CTL_MSG *request, CTL_RESPONSE *response)
188 {
189 TABLE_ENTRY *ptr;
190 long current_time;
191
192 (void) gettimeofday(&tp, NULL);
193 current_time = tp.tv_sec;
194
195 response->id_num = request->id_num = new_id();
196
197 /*
198 * Insert a new entry into the top of the list.
199 */
200 ptr = (TABLE_ENTRY *) malloc(sizeof (TABLE_ENTRY));
201
202 if (ptr == NULL) {
203 print_error("malloc in insert_table");
204 }
205
206 ptr->time = current_time;
207 ptr->request = *request;
208
209 ptr->next = table;
210 if (ptr->next != NULL) {
211 ptr->next->last = ptr;
212 }
213 ptr->last = NULL;
214 table = ptr;
215 }
216
217 /*
218 * Generate a unique non-zero sequence number.
219 */
220
221 int
new_id(void)222 new_id(void)
223 {
224 static int current_id = 0;
225
226 current_id = (current_id + 1) % MAX_ID;
227
228 /* 0 is reserved, helps to pick up bugs */
229 if (current_id == 0)
230 current_id = 1;
231
232 return (current_id);
233 }
234
235 /*
236 * Delete the invitation with id 'id_num'.
237 */
238
239 int
delete_invite(int id_num)240 delete_invite(int id_num)
241 {
242 TABLE_ENTRY *ptr;
243
244 ptr = table;
245
246 if (debug)
247 (void) printf("Entering delete_invite with %d\n", id_num);
248
249 while (ptr != NULL && ptr->request.id_num != id_num) {
250 if (debug)
251 print_request(&ptr->request);
252 ptr = ptr->next;
253 }
254
255 if (ptr != NULL) {
256 delete(ptr);
257 return (SUCCESS);
258 }
259
260 return (NOT_HERE);
261 }
262
263 /*
264 * Classic delete from a double-linked list.
265 */
266
267 static void
delete(TABLE_ENTRY * ptr)268 delete(TABLE_ENTRY *ptr)
269 {
270 if (debug) {
271 (void) printf("Deleting : ");
272 print_request(&ptr->request);
273 }
274 if (table == ptr) {
275 table = ptr->next;
276 } else if (ptr->last != NULL) {
277 ptr->last->next = ptr->next;
278 }
279
280 if (ptr->next != NULL) {
281 ptr->next->last = ptr->last;
282 }
283
284 free(ptr);
285 }
286