Merge res_timing_pthread. This is a timing interface for Asterisk that

does not require DAHDI.  It's called "pthread" because it uses a pthread
API call in the timing thread for sleeping and ensuring we wake up at
an appropriate time.  I wasn't sure what else to call it.  :)

The timing API requires a file descriptor that can be polled on.  So,
when you open a timer, this module creates a pipe and returns the read
end of the pipe.  There is a background thread that wakes up every 10ms
and checks to see if any of the currently open timers need a 'tick' and
writes to the appropriate pipe.


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@122928 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 480 insertions, 0 deletions

diff --git a/res/res_timing_pthread.c b/res/res_timing_pthread.c
new file mode 100644
index 000000000..6b17e9b85
--- /dev/null
+++ b/res/res_timing_pthread.c
@@ -0,0 +1,480 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2008, Digium, Inc.
+ *
+ * Russell Bryant <russell@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! 
+ * \file
+ * \author Russell Bryant <russell@digium.com>
+ *
+ * \brief pthread timing interface 
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$");
+
+#include <math.h>
+#include <sys/select.h>
+
+#include "asterisk/module.h"
+#include "asterisk/timing.h"
+#include "asterisk/utils.h"
+#include "asterisk/astobj2.h"
+#include "asterisk/time.h"
+#include "asterisk/lock.h"
+
+static void *timing_funcs_handle;
+
+static int pthread_timer_open(void);
+static void pthread_timer_close(int handle);
+static int pthread_timer_set_rate(int handle, unsigned int rate);
+static void pthread_timer_ack(int handle, unsigned int quantity);
+static int pthread_timer_enable_continuous(int handle);
+static int pthread_timer_disable_continuous(int handle);
+static enum ast_timing_event pthread_timer_get_event(int handle);
+
+static struct ast_timing_functions pthread_timing_functions = {
+	.timer_open = pthread_timer_open,
+	.timer_close = pthread_timer_close,
+	.timer_set_rate = pthread_timer_set_rate,
+	.timer_ack = pthread_timer_ack,
+	.timer_enable_continuous = pthread_timer_enable_continuous,
+	.timer_disable_continuous = pthread_timer_disable_continuous,
+	.timer_get_event = pthread_timer_get_event,
+};
+
+/* 1 tick / 20 ms */
+#define TIMING_INTERVAL 20
+#define MAX_RATE 50
+
+static struct ao2_container *pthread_timers;
+#define PTHREAD_TIMER_BUCKETS 563
+
+enum {
+	PIPE_READ =  0,
+	PIPE_WRITE = 1
+};
+
+enum pthread_timer_state {
+	TIMER_STATE_IDLE,
+	TIMER_STATE_TICKING,
+	TIMER_STATE_CONTINUOUS,
+};
+
+struct pthread_timer {
+	int pipe[2];
+	enum pthread_timer_state state;
+	unsigned int rate;
+	/*! Interval in ms for current rate */
+	unsigned int interval;
+	unsigned int tick_count;
+	struct timeval start;
+};
+
+static void pthread_timer_destructor(void *obj);
+static struct pthread_timer *find_timer(int handle, int unlink);
+static void write_byte(int wr_fd);
+static void read_pipe(int rd_fd, unsigned int num, int clear);
+
+/*!
+ * \brief Data for the timing thread
+ */
+static struct {
+	pthread_t thread;
+	ast_mutex_t lock;
+	ast_cond_t cond;
+	unsigned int stop:1;
+} timing_thread;
+
+static int pthread_timer_open(void)
+{
+	struct pthread_timer *timer;
+
+	if (!(timer = ao2_alloc(sizeof(*timer), pthread_timer_destructor))) {
+		errno = ENOMEM;
+		return -1;
+	}
+
+	timer->pipe[PIPE_READ] = timer->pipe[PIPE_WRITE] = -1;
+	timer->state = TIMER_STATE_IDLE;
+
+	if (pipe(timer->pipe)) {
+		ao2_ref(timer, -1);
+		return -1;
+	}
+
+	ao2_lock(pthread_timers);
+	if (!ao2_container_count(pthread_timers)) {
+		ast_mutex_lock(&timing_thread.lock);
+		ast_cond_signal(&timing_thread.cond);
+		ast_mutex_unlock(&timing_thread.lock);
+	}
+	ao2_link(pthread_timers, timer);
+	ao2_unlock(pthread_timers);
+
+	return timer->pipe[PIPE_READ];
+}
+
+static void pthread_timer_close(int handle)
+{
+	struct pthread_timer *timer;
+
+	if (!(timer = find_timer(handle, 1))) {
+		return;
+	}
+
+	ao2_ref(timer, -1);
+}
+
+static int pthread_timer_set_rate(int handle, unsigned int rate)
+{
+	struct pthread_timer *timer;
+
+	if (!(timer = find_timer(handle, 0))) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (rate > 0 && rate < MAX_RATE) {
+		ast_log(LOG_ERROR, "res_timing_pthread only supports timers at a max rate of %d / sec\n",
+			MAX_RATE);
+		errno = EINVAL;
+		return -1;
+	}
+
+	ao2_lock(timer);
+	timer->rate = rate;
+	timer->state = rate ? TIMER_STATE_TICKING : TIMER_STATE_IDLE;
+	timer->interval = rate ? roundf(1000.0 / ((float) rate)) : 0;
+	timer->start = rate ? ast_tvnow() : ast_tv(0, 0);
+	timer->tick_count = 0;
+	ao2_unlock(timer);
+
+	ao2_ref(timer, -1);
+
+	return 0;
+}
+
+static void pthread_timer_ack(int handle, unsigned int quantity)
+{
+	struct pthread_timer *timer;
+
+	ast_assert(quantity > 0);
+
+	if (!(timer = find_timer(handle, 0))) {
+		return;
+	}
+
+	if (timer->state == TIMER_STATE_CONTINUOUS) {
+		/* Leave the pipe alone, please! */
+		return;
+	}
+
+	read_pipe(timer->pipe[PIPE_READ], quantity, 0);
+
+	ao2_ref(timer, -1);
+}
+
+static int pthread_timer_enable_continuous(int handle)
+{
+	struct pthread_timer *timer;
+
+	if (!(timer = find_timer(handle, 0))) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	ao2_lock(timer);
+	timer->state = TIMER_STATE_CONTINUOUS;
+	write_byte(timer->pipe[PIPE_WRITE]);
+	ao2_unlock(timer);
+
+	ao2_ref(timer, -1);
+
+	return 0;
+}
+
+static int pthread_timer_disable_continuous(int handle)
+{
+	struct pthread_timer *timer;
+
+	if (!(timer = find_timer(handle, 0))) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	ao2_lock(timer);
+	timer->state = timer->rate ? TIMER_STATE_TICKING : TIMER_STATE_IDLE;
+	read_pipe(timer->pipe[PIPE_READ], 0, 1);
+	ao2_unlock(timer);
+
+	ao2_ref(timer, -1);
+
+	return 0;
+}
+
+static enum ast_timing_event pthread_timer_get_event(int handle)
+{
+	struct pthread_timer *timer;
+	enum ast_timing_event res = AST_TIMING_EVENT_EXPIRED;
+
+	if (!(timer = find_timer(handle, 0))) {
+		return res;
+	}
+
+	if (timer->state == TIMER_STATE_CONTINUOUS) {
+		res = AST_TIMING_EVENT_CONTINUOUS;
+	}
+
+	ao2_ref(timer, -1);
+
+	return res;
+}
+
+static struct pthread_timer *find_timer(int handle, int unlink)
+{
+	struct pthread_timer *timer;
+	struct pthread_timer tmp_timer;
+	int flags = OBJ_POINTER;
+
+	tmp_timer.pipe[PIPE_READ] = handle;
+
+	if (unlink) {
+		flags |= OBJ_UNLINK;
+	}
+
+	if (!(timer = ao2_find(pthread_timers, &tmp_timer, flags))) {
+		ast_assert(timer != NULL);
+		return NULL;
+	}
+
+	return timer;
+}
+
+static void pthread_timer_destructor(void *obj)
+{
+	struct pthread_timer *timer = obj;
+
+	if (timer->pipe[PIPE_READ] > -1) {
+		close(timer->pipe[PIPE_READ]);
+		timer->pipe[PIPE_READ] = -1;
+	}
+
+	if (timer->pipe[PIPE_WRITE] > -1) {
+		close(timer->pipe[PIPE_WRITE]);
+		timer->pipe[PIPE_WRITE] = -1;
+	}
+}
+
+/*!
+ * \note only PIPE_READ is guaranteed valid 
+ */
+static int pthread_timer_hash(const void *obj, const int flags)
+{
+	const struct pthread_timer *timer = obj;
+
+	return timer->pipe[PIPE_READ];
+}
+
+/*!
+ * \note only PIPE_READ is guaranteed valid 
+ */
+static int pthread_timer_cmp(void *obj, void *arg, int flags)
+{
+	struct pthread_timer *timer1 = obj, *timer2 = arg;
+
+	return (timer1->pipe[PIPE_READ] == timer2->pipe[PIPE_READ]) ? CMP_MATCH : 0;
+}
+
+/*!
+ * \retval 0 no timer tick needed
+ * \retval non-zero write to the timing pipe needed
+ */
+static int check_timer(struct pthread_timer *timer)
+{
+	struct timeval now;
+
+	if (timer->state == TIMER_STATE_IDLE || timer->state == TIMER_STATE_CONTINUOUS) {
+		return 0;	
+	}
+	
+	now = ast_tvnow();
+
+	if (timer->tick_count < (ast_tvdiff_ms(now, timer->start) / timer->interval)) {
+		timer->tick_count++;
+		if (!timer->tick_count) {
+			timer->start = now;
+		}
+		return 1;
+	}
+
+	return 0;
+}
+
+static void read_pipe(int rd_fd, unsigned int quantity, int clear)
+{
+
+	ast_assert(quantity || clear);
+
+	if (!quantity && clear) {
+		quantity = 1;
+	}
+
+	do {
+		unsigned char buf[1024];
+		ssize_t res;
+		fd_set rfds;
+		struct timeval tv = {
+			.tv_sec = 0,
+		};
+
+		/* Make sure there is data to read */
+		FD_ZERO(&rfds);
+		FD_SET(rd_fd, &rfds);
+
+		if (select(rd_fd + 1, &rfds, NULL, NULL, &tv) != 1) {
+			break;
+		}
+
+		res = read(rd_fd, buf, 
+			(quantity < sizeof(buf)) ? quantity : sizeof(buf));
+
+		if (res == -1) {
+			if (errno == EAGAIN) {
+				continue;
+			}
+			ast_log(LOG_ERROR, "read failed on timing pipe: %s\n", strerror(errno));
+			break;
+		}
+
+		if (clear) {
+			continue;
+		}
+
+		quantity -= res;
+	} while (quantity);
+}
+
+static void write_byte(int wr_fd)
+{
+	do {
+		ssize_t res;
+		unsigned char x = 42;
+
+		res = write(wr_fd, &x, 1); 
+
+		if (res == -1) {
+			if (errno == EAGAIN) {
+				continue;
+			}
+			ast_log(LOG_ERROR, "Error writing to timing pipe: %s\n", strerror(errno));
+		}
+	} while (0);
+}
+
+static int run_timer(void *obj, void *arg, int flags)
+{
+	struct pthread_timer *timer = obj;
+
+	if (timer->state == TIMER_STATE_IDLE) {
+		return 0;
+	}
+
+	ao2_lock(timer);
+
+	if (check_timer(timer)) {
+		write_byte(timer->pipe[PIPE_WRITE]);
+	}
+	
+	ao2_unlock(timer);
+
+	return 0;
+}
+
+static void *do_timing(void *arg)
+{
+	struct timeval next_wakeup = ast_tvnow();
+
+	while (!timing_thread.stop) {
+		struct timespec ts = { 0, };
+
+		ao2_callback(pthread_timers, 0, run_timer, NULL);
+
+		next_wakeup = ast_tvadd(next_wakeup, ast_tv(0, 10000));
+
+		ts.tv_sec = next_wakeup.tv_sec;
+		ts.tv_nsec = next_wakeup.tv_usec * 1000;
+
+		ast_mutex_lock(&timing_thread.lock);
+		if (!timing_thread.stop) {
+			if (ao2_container_count(pthread_timers)) {
+				ast_cond_timedwait(&timing_thread.cond, &timing_thread.lock, &ts);
+			} else {
+				ast_cond_wait(&timing_thread.cond, &timing_thread.lock);
+			}
+		}
+		ast_mutex_unlock(&timing_thread.lock);
+	}
+
+	return NULL;
+}
+
+static int init_timing_thread(void)
+{
+	ast_mutex_init(&timing_thread.lock);
+	ast_cond_init(&timing_thread.cond, NULL);
+
+	if (ast_pthread_create_background(&timing_thread.thread, NULL, do_timing, NULL)) {
+		ast_log(LOG_ERROR, "Unable to start timing thread.\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int load_module(void)
+{
+	if (!(pthread_timers = ao2_container_alloc(PTHREAD_TIMER_BUCKETS, 
+		pthread_timer_hash, pthread_timer_cmp))) {
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	if (init_timing_thread()) {
+		ao2_ref(pthread_timers, -1);
+		pthread_timers = NULL;
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	return (timing_funcs_handle = ast_install_timing_functions(&pthread_timing_functions)) ?
+		AST_MODULE_LOAD_SUCCESS : AST_MODULE_LOAD_DECLINE;
+}
+
+static int unload_module(void)
+{
+#if 0
+	/* XXX code to stop the timing thread ... */
+
+	ast_uninstall_timing_functions(timing_funcs_handle);
+	ao2_ref(pthread_timers, -1);
+#endif
+
+	/* This module can not currently be unloaded.  No use count handling is being done. */
+
+	return -1;
+}
+
+AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "pthread Timing Interface");