1 /*
2 * event.h
3 */
4
5 /*-
6 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
7 *
8 * Copyright (c) 2009 Maksim Yevmenkin <m_evmenkin@yahoo.com>
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /* $FreeBSD: stable/12/usr.sbin/bluetooth/btpand/event.c 326276 2017-11-27 15:37:16Z pfg $ */
34
35 /*
36 * Hack to provide libevent (see devel/libevent port) like API.
37 * Should be removed if FreeBSD ever decides to import libevent into base.
38 */
39
40 #include <sys/select.h>
41 #include <sys/time.h>
42 #include <sys/queue.h>
43 #include <assert.h>
44 #include <stdarg.h>
45 #include <stdio.h>
46 #include <string.h>
47 #include <syslog.h>
48
49 #include "event.h"
50 #define L2CAP_SOCKET_CHECKED
51 #include "btpand.h"
52
53 #define __event_link(ev) \
54 do { \
55 TAILQ_INSERT_TAIL(&pending, ev, next); \
56 ev->flags |= EV_PENDING; \
57 } while (0)
58
59 static void tv_add(struct timeval *, struct timeval const *);
60 static void tv_sub(struct timeval *, struct timeval const *);
61 static int tv_cmp(struct timeval const *, struct timeval const *);
62 static int __event_dispatch(void);
63 static void __event_add_current(struct event *);
64 static void __event_del_current(struct event *);
65
66
67 static TAILQ_HEAD(, event) pending;
68 static TAILQ_HEAD(, event) current;
69
70 void
event_init(void)71 event_init(void)
72 {
73 TAILQ_INIT(&pending);
74 }
75
76 int
event_dispatch(void)77 event_dispatch(void)
78 {
79 while (__event_dispatch() == 0)
80 ;
81
82 return (-1);
83 }
84
85 static int
__event_dispatch(void)86 __event_dispatch(void)
87 {
88 fd_set r, w;
89 int nfd;
90 struct event *ev;
91 struct timeval now, timeout, t;
92
93 FD_ZERO(&r);
94 FD_ZERO(&w);
95
96 nfd = 0;
97
98 gettimeofday(&now, NULL);
99
100 timeout.tv_sec = 10; /* arbitrary */
101 timeout.tv_usec = 0;
102
103 TAILQ_INIT(¤t);
104
105 /*
106 * Build fd_set's
107 */
108
109 event_log_debug("%s: building fd set...", __func__);
110
111 while (!TAILQ_EMPTY(&pending)) {
112 ev = TAILQ_FIRST(&pending);
113 event_del(ev);
114
115 if (ev->flags & EV_HAS_TIMEOUT) {
116 if (tv_cmp(&now, &ev->expire) >= 0)
117 t.tv_sec = t.tv_usec = 0;
118 else {
119 t = ev->expire;
120 tv_sub(&t, &now);
121 }
122
123 if (tv_cmp(&t, &timeout) < 0)
124 timeout = t;
125 }
126
127 if (ev->fd >= 0) {
128 if (ev->flags & EV_READ) {
129 FD_SET(ev->fd, &r);
130 nfd = (nfd > ev->fd) ? nfd : ev->fd;
131 }
132
133 if (ev->flags & EV_WRITE) {
134 FD_SET(ev->fd, &w);
135 nfd = (nfd > ev->fd) ? nfd : ev->fd;
136 }
137 }
138
139 __event_add_current(ev);
140 }
141
142 event_log_debug("%s: waiting for events...", __func__);
143
144 nfd = select(nfd + 1, &r, &w, NULL, &timeout);
145 if (nfd < 0)
146 return (-1);
147
148 /*
149 * Process current pending
150 */
151
152 event_log_debug("%s: processing events...", __func__);
153
154 gettimeofday(&now, NULL);
155
156 while (!TAILQ_EMPTY(¤t)) {
157 ev = TAILQ_FIRST(¤t);
158 __event_del_current(ev);
159
160 /* check if fd is ready for reading/writing */
161 if (nfd > 0 && ev->fd >= 0) {
162 if (FD_ISSET(ev->fd, &r) || FD_ISSET(ev->fd, &w)) {
163 if (ev->flags & EV_PERSIST) {
164 if (ev->flags & EV_HAS_TIMEOUT)
165 event_add(ev, &ev->timeout);
166 else
167 event_add(ev, NULL);
168 }
169
170 nfd --;
171
172 event_log_debug("%s: calling %p(%d, %p), " \
173 "ev=%p", __func__, ev->cb, ev->fd,
174 ev->cbarg, ev);
175
176 (ev->cb)(ev->fd,
177 (ev->flags & (EV_READ|EV_WRITE)),
178 ev->cbarg);
179
180 continue;
181 }
182 }
183
184 /* if event has no timeout - just requeue */
185 if ((ev->flags & EV_HAS_TIMEOUT) == 0) {
186 event_add(ev, NULL);
187 continue;
188 }
189
190 /* check if event has expired */
191 if (tv_cmp(&now, &ev->expire) >= 0) {
192 if (ev->flags & EV_PERSIST)
193 event_add(ev, &ev->timeout);
194
195 event_log_debug("%s: calling %p(%d, %p), ev=%p",
196 __func__, ev->cb, ev->fd, ev->cbarg, ev);
197
198 (ev->cb)(ev->fd,
199 (ev->flags & (EV_READ|EV_WRITE)),
200 ev->cbarg);
201
202 continue;
203 }
204
205 assert((ev->flags & (EV_PENDING|EV_CURRENT)) == 0);
206 __event_link(ev);
207 }
208
209 return (0);
210 }
211
212 void
__event_set(struct event * ev,int fd,short flags,void (* cb)(int,short,void *),void * cbarg)213 __event_set(struct event *ev, int fd, short flags,
214 void (*cb)(int, short, void *), void *cbarg)
215 {
216 ev->fd = fd;
217 ev->flags = flags;
218 ev->cb = cb;
219 ev->cbarg = cbarg;
220 }
221
222 int
__event_add(struct event * ev,const struct timeval * timeout)223 __event_add(struct event *ev, const struct timeval *timeout)
224 {
225 assert((ev->flags & (EV_PENDING|EV_CURRENT)) == 0);
226
227 if (timeout != NULL) {
228 gettimeofday(&ev->expire, NULL);
229 tv_add(&ev->expire, timeout);
230 ev->timeout = *timeout;
231 ev->flags |= EV_HAS_TIMEOUT;
232 } else
233 ev->flags &= ~EV_HAS_TIMEOUT;
234
235 __event_link(ev);
236
237 return (0);
238 }
239
240 int
__event_del(struct event * ev)241 __event_del(struct event *ev)
242 {
243 assert((ev->flags & EV_CURRENT) == 0);
244
245 if ((ev->flags & EV_PENDING) != 0) {
246 TAILQ_REMOVE(&pending, ev, next);
247 ev->flags &= ~EV_PENDING;
248 }
249
250 return (0);
251 }
252
253 static void
__event_add_current(struct event * ev)254 __event_add_current(struct event *ev)
255 {
256 assert((ev->flags & (EV_PENDING|EV_CURRENT)) == 0);
257
258 TAILQ_INSERT_TAIL(¤t, ev, next);
259 ev->flags |= EV_CURRENT;
260 }
261
262 static void
__event_del_current(struct event * ev)263 __event_del_current(struct event *ev)
264 {
265 assert((ev->flags & (EV_CURRENT|EV_PENDING)) == EV_CURRENT);
266
267 TAILQ_REMOVE(¤t, ev, next);
268 ev->flags &= ~EV_CURRENT;
269 }
270
271 static void
tv_add(struct timeval * a,struct timeval const * b)272 tv_add(struct timeval *a, struct timeval const *b)
273 {
274 a->tv_sec += b->tv_sec;
275 a->tv_usec += b->tv_usec;
276
277 if(a->tv_usec >= 1000000) {
278 a->tv_usec -= 1000000;
279 a->tv_sec += 1;
280 }
281 }
282
283 static void
tv_sub(struct timeval * a,struct timeval const * b)284 tv_sub(struct timeval *a, struct timeval const *b)
285 {
286 if (a->tv_usec < b->tv_usec) {
287 a->tv_usec += 1000000;
288 a->tv_sec -= 1;
289 }
290
291 a->tv_usec -= b->tv_usec;
292 a->tv_sec -= b->tv_sec;
293 }
294
295 static int
tv_cmp(struct timeval const * a,struct timeval const * b)296 tv_cmp(struct timeval const *a, struct timeval const *b)
297 {
298 if (a->tv_sec > b->tv_sec)
299 return (1);
300
301 if (a->tv_sec < b->tv_sec)
302 return (-1);
303
304 if (a->tv_usec > b->tv_usec)
305 return (1);
306
307 if (a->tv_usec < b->tv_usec)
308 return (-1);
309
310 return (0);
311 }
312
313