res_pjsip_transport_websocket: Don't assert on 0 length payloads
[asterisk/asterisk.git] / res / res_timing_pthread.c
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2008, Digium, Inc.
5  *
6  * Russell Bryant <russell@digium.com>
7  *
8  * See http://www.asterisk.org for more information about
9  * the Asterisk project. Please do not directly contact
10  * any of the maintainers of this project for assistance;
11  * the project provides a web site, mailing lists and IRC
12  * channels for your use.
13  *
14  * This program is free software, distributed under the terms of
15  * the GNU General Public License Version 2. See the LICENSE file
16  * at the top of the source tree.
17  */
18
19 /*!
20  * \file
21  * \author Russell Bryant <russell@digium.com>
22  *
23  * \brief pthread timing interface
24  */
25
26 /*** MODULEINFO
27         <support_level>extended</support_level>
28  ***/
29
30 #include "asterisk.h"
31
32 #include <stdbool.h>
33 #include <math.h>
34 #include <unistd.h>
35 #include <fcntl.h>
36
37 #include "asterisk/module.h"
38 #include "asterisk/timing.h"
39 #include "asterisk/utils.h"
40 #include "asterisk/astobj2.h"
41 #include "asterisk/time.h"
42 #include "asterisk/lock.h"
43
44 static void *timing_funcs_handle;
45
46 static void *pthread_timer_open(void);
47 static void pthread_timer_close(void *data);
48 static int pthread_timer_set_rate(void *data, unsigned int rate);
49 static int pthread_timer_ack(void *data, unsigned int quantity);
50 static int pthread_timer_enable_continuous(void *data);
51 static int pthread_timer_disable_continuous(void *data);
52 static enum ast_timer_event pthread_timer_get_event(void *data);
53 static unsigned int pthread_timer_get_max_rate(void *data);
54 static int pthread_timer_fd(void *data);
55
56 static struct ast_timing_interface pthread_timing = {
57         .name = "pthread",
58         .priority = 0, /* use this as a last resort */
59         .timer_open = pthread_timer_open,
60         .timer_close = pthread_timer_close,
61         .timer_set_rate = pthread_timer_set_rate,
62         .timer_ack = pthread_timer_ack,
63         .timer_enable_continuous = pthread_timer_enable_continuous,
64         .timer_disable_continuous = pthread_timer_disable_continuous,
65         .timer_get_event = pthread_timer_get_event,
66         .timer_get_max_rate = pthread_timer_get_max_rate,
67         .timer_fd = pthread_timer_fd,
68 };
69
70 /* 1 tick / 10 ms */
71 #define MAX_RATE 100
72
73 static struct ao2_container *pthread_timers;
74 #define PTHREAD_TIMER_BUCKETS 563
75
76 enum {
77         PIPE_READ =  0,
78         PIPE_WRITE = 1
79 };
80
81 enum pthread_timer_state {
82         TIMER_STATE_IDLE,
83         TIMER_STATE_TICKING,
84 };
85
86 struct pthread_timer {
87         int pipe[2];
88         enum pthread_timer_state state;
89         unsigned int rate;
90         /*! Interval in ms for current rate */
91         unsigned int interval;
92         unsigned int tick_count;
93         unsigned int pending_ticks;
94         struct timeval start;
95         bool continuous:1;
96         bool pipe_signaled:1;
97 };
98
99 static void pthread_timer_destructor(void *obj);
100 static void signal_pipe(struct pthread_timer *timer);
101 static void unsignal_pipe(struct pthread_timer *timer);
102 static void ack_ticks(struct pthread_timer *timer, unsigned int num);
103
104 /*!
105  * \brief Data for the timing thread
106  */
107 static struct {
108         pthread_t thread;
109         ast_mutex_t lock;
110         ast_cond_t cond;
111         unsigned int stop:1;
112 } timing_thread;
113
114 static void *pthread_timer_open(void)
115 {
116         struct pthread_timer *timer;
117
118         if (!(timer = ao2_alloc(sizeof(*timer), pthread_timer_destructor))) {
119                 errno = ENOMEM;
120                 return NULL;
121         }
122
123         timer->pipe[PIPE_READ] = timer->pipe[PIPE_WRITE] = -1;
124         timer->state = TIMER_STATE_IDLE;
125
126         if (ast_pipe_nonblock(timer->pipe)) {
127                 ao2_ref(timer, -1);
128                 return NULL;
129         }
130
131         ao2_lock(pthread_timers);
132         if (!ao2_container_count(pthread_timers)) {
133                 ast_mutex_lock(&timing_thread.lock);
134                 ast_cond_signal(&timing_thread.cond);
135                 ast_mutex_unlock(&timing_thread.lock);
136         }
137         ao2_link_flags(pthread_timers, timer, OBJ_NOLOCK);
138         ao2_unlock(pthread_timers);
139
140         return timer;
141 }
142
143 static void pthread_timer_close(void *data)
144 {
145         struct pthread_timer *timer = data;
146
147         ao2_unlink(pthread_timers, timer);
148         ao2_ref(timer, -1);
149 }
150
151 static int pthread_timer_set_rate(void *data, unsigned int rate)
152 {
153         struct pthread_timer *timer = data;
154
155         if (rate > MAX_RATE) {
156                 ast_log(LOG_ERROR, "res_timing_pthread only supports timers at a "
157                                 "max rate of %d / sec\n", MAX_RATE);
158                 errno = EINVAL;
159                 return -1;
160         }
161
162         ao2_lock(timer);
163
164         if ((timer->rate = rate)) {
165                 timer->interval = roundf(1000.0 / ((float) rate));
166                 timer->start = ast_tvnow();
167                 timer->state = TIMER_STATE_TICKING;
168         } else {
169                 timer->interval = 0;
170                 timer->start = ast_tv(0, 0);
171                 timer->state = TIMER_STATE_IDLE;
172         }
173         timer->tick_count = 0;
174
175         ao2_unlock(timer);
176
177         return 0;
178 }
179
180 static int pthread_timer_ack(void *data, unsigned int quantity)
181 {
182         struct pthread_timer *timer = data;
183
184         ast_assert(quantity > 0);
185
186         ao2_lock(timer);
187         ack_ticks(timer, quantity);
188         ao2_unlock(timer);
189
190         return 0;
191 }
192
193 static int pthread_timer_enable_continuous(void *data)
194 {
195         struct pthread_timer *timer = data;
196
197         ao2_lock(timer);
198         if (!timer->continuous) {
199                 timer->continuous = true;
200                 signal_pipe(timer);
201         }
202         ao2_unlock(timer);
203
204         return 0;
205 }
206
207 static int pthread_timer_disable_continuous(void *data)
208 {
209         struct pthread_timer *timer = data;
210
211         ao2_lock(timer);
212         if (timer->continuous) {
213                 timer->continuous = false;
214                 unsignal_pipe(timer);
215         }
216         ao2_unlock(timer);
217
218         return 0;
219 }
220
221 static enum ast_timer_event pthread_timer_get_event(void *data)
222 {
223         struct pthread_timer *timer = data;
224         enum ast_timer_event res = AST_TIMING_EVENT_EXPIRED;
225
226         ao2_lock(timer);
227         if (timer->continuous) {
228                 res = AST_TIMING_EVENT_CONTINUOUS;
229         }
230         ao2_unlock(timer);
231
232         return res;
233 }
234
235 static unsigned int pthread_timer_get_max_rate(void *data)
236 {
237         return MAX_RATE;
238 }
239
240 static int pthread_timer_fd(void *data)
241 {
242         struct pthread_timer *timer = data;
243
244         return timer->pipe[PIPE_READ];
245 }
246
247 static void pthread_timer_destructor(void *obj)
248 {
249         struct pthread_timer *timer = obj;
250
251         if (timer->pipe[PIPE_READ] > -1) {
252                 close(timer->pipe[PIPE_READ]);
253                 timer->pipe[PIPE_READ] = -1;
254         }
255
256         if (timer->pipe[PIPE_WRITE] > -1) {
257                 close(timer->pipe[PIPE_WRITE]);
258                 timer->pipe[PIPE_WRITE] = -1;
259         }
260 }
261
262 /*!
263  * \note only PIPE_READ is guaranteed valid
264  */
265 static int pthread_timer_hash(const void *obj, const int flags)
266 {
267         const struct pthread_timer *timer = obj;
268
269         return timer->pipe[PIPE_READ];
270 }
271
272 /*!
273  * \note only PIPE_READ is guaranteed valid
274  */
275 static int pthread_timer_cmp(void *obj, void *arg, int flags)
276 {
277         struct pthread_timer *timer1 = obj, *timer2 = arg;
278
279         return (timer1->pipe[PIPE_READ] == timer2->pipe[PIPE_READ]) ? CMP_MATCH | CMP_STOP : 0;
280 }
281
282 /*!
283  * \retval 0 no timer tick needed
284  * \retval non-zero write to the timing pipe needed
285  */
286 static int check_timer(struct pthread_timer *timer)
287 {
288         struct timeval now;
289
290         if (timer->state == TIMER_STATE_IDLE) {
291                 return 0;
292         }
293
294         now = ast_tvnow();
295
296         if (timer->tick_count < (ast_tvdiff_ms(now, timer->start) / timer->interval)) {
297                 timer->tick_count++;
298                 if (!timer->tick_count) {
299                         /* Handle overflow. */
300                         timer->start = now;
301                 }
302                 return 1;
303         }
304
305         return 0;
306 }
307
308 /*!
309  * \internal
310  * \pre timer is locked
311  */
312 static void ack_ticks(struct pthread_timer *timer, unsigned int quantity)
313 {
314         int pending_ticks = timer->pending_ticks;
315
316         ast_assert(quantity);
317
318         if (quantity > pending_ticks) {
319                 quantity = pending_ticks;
320         }
321
322         if (!quantity) {
323                 return;
324         }
325
326         timer->pending_ticks -= quantity;
327
328         if ((0 == timer->pending_ticks) && !timer->continuous) {
329                 unsignal_pipe(timer);
330         }
331 }
332
333 /*!
334  * \internal
335  * \pre timer is locked
336  */
337 static void signal_pipe(struct pthread_timer *timer)
338 {
339         ssize_t res;
340         unsigned char x = 42;
341
342         if (timer->pipe_signaled) {
343                 return;
344         }
345
346         res = write(timer->pipe[PIPE_WRITE], &x, 1);
347         if (-1 == res) {
348                 ast_log(LOG_ERROR, "Error writing to timing pipe: %s\n",
349                                 strerror(errno));
350         } else {
351                 timer->pipe_signaled = true;
352         }
353 }
354
355 /*!
356  * \internal
357  * \pre timer is locked
358  */
359 static void unsignal_pipe(struct pthread_timer *timer)
360 {
361         ssize_t res;
362         unsigned long buffer;
363
364         if (!timer->pipe_signaled) {
365                 return;
366         }
367
368         res = read(timer->pipe[PIPE_READ], &buffer, sizeof(buffer));
369         if (-1 == res) {
370                 ast_log(LOG_ERROR, "Error reading from pipe: %s\n",
371                                 strerror(errno));
372         } else {
373                 timer->pipe_signaled = false;
374         }
375 }
376
377 static int run_timer(void *obj, void *arg, int flags)
378 {
379         struct pthread_timer *timer = obj;
380
381         if (timer->state == TIMER_STATE_IDLE) {
382                 return 0;
383         }
384
385         ao2_lock(timer);
386         if (check_timer(timer)) {
387                 timer->pending_ticks++;
388                 signal_pipe(timer);
389         }
390         ao2_unlock(timer);
391
392         return 0;
393 }
394
395 static void *do_timing(void *arg)
396 {
397         struct timeval next_wakeup = ast_tvnow();
398
399         while (!timing_thread.stop) {
400                 struct timespec ts = { 0, };
401
402                 ao2_callback(pthread_timers, OBJ_NODATA, run_timer, NULL);
403
404                 next_wakeup = ast_tvadd(next_wakeup, ast_tv(0, 5000));
405
406                 ts.tv_sec = next_wakeup.tv_sec;
407                 ts.tv_nsec = next_wakeup.tv_usec * 1000;
408
409                 ast_mutex_lock(&timing_thread.lock);
410                 if (!timing_thread.stop) {
411                         if (ao2_container_count(pthread_timers)) {
412                                 ast_cond_timedwait(&timing_thread.cond, &timing_thread.lock, &ts);
413                         } else {
414                                 ast_cond_wait(&timing_thread.cond, &timing_thread.lock);
415                         }
416                 }
417                 ast_mutex_unlock(&timing_thread.lock);
418         }
419
420         return NULL;
421 }
422
423 static int init_timing_thread(void)
424 {
425         ast_mutex_init(&timing_thread.lock);
426         ast_cond_init(&timing_thread.cond, NULL);
427
428         if (ast_pthread_create_background(&timing_thread.thread, NULL, do_timing, NULL)) {
429                 ast_log(LOG_ERROR, "Unable to start timing thread.\n");
430                 return -1;
431         }
432
433         return 0;
434 }
435
436 static int load_module(void)
437 {
438         pthread_timers = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
439                 PTHREAD_TIMER_BUCKETS, pthread_timer_hash, NULL, pthread_timer_cmp);
440         if (!pthread_timers) {
441                 return AST_MODULE_LOAD_DECLINE;
442         }
443
444         if (init_timing_thread()) {
445                 ao2_ref(pthread_timers, -1);
446                 pthread_timers = NULL;
447                 return AST_MODULE_LOAD_DECLINE;
448         }
449
450         return (timing_funcs_handle = ast_register_timing_interface(&pthread_timing)) ?
451                 AST_MODULE_LOAD_SUCCESS : AST_MODULE_LOAD_DECLINE;
452 }
453
454 static int unload_module(void)
455 {
456         int res;
457
458         ast_mutex_lock(&timing_thread.lock);
459         timing_thread.stop = 1;
460         ast_cond_signal(&timing_thread.cond);
461         ast_mutex_unlock(&timing_thread.lock);
462         pthread_join(timing_thread.thread, NULL);
463
464         if (!(res = ast_unregister_timing_interface(timing_funcs_handle))) {
465                 ao2_ref(pthread_timers, -1);
466                 pthread_timers = NULL;
467         }
468
469         return res;
470 }
471 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "pthread Timing Interface",
472         .support_level = AST_MODULE_SUPPORT_EXTENDED,
473         .load = load_module,
474         .unload = unload_module,
475         .load_pri = AST_MODPRI_TIMING,
476 );