Added a wrapper class around POSIX semaphores.

src/libstrongswan/Android.mk

@@ -62,6 +62,7 @@ selectors/traffic_selector.c selectors/traffic_selector.h \
 threading/thread.h threading/thread.c \
 threading/thread_value.h threading/thread_value.c \
 threading/mutex.h threading/mutex.c threading/condvar.h  \
+threading/semaphore.h threading/semaphore.c \
 threading/rwlock.h threading/rwlock.c \
 threading/lock_profiler.h \
 utils.h utils.c \

src/libstrongswan/Makefile.am

@@ -60,6 +60,7 @@ selectors/traffic_selector.c selectors/traffic_selector.h \
 threading/thread.h threading/thread.c \
 threading/thread_value.h threading/thread_value.c \
 threading/mutex.h threading/mutex.c threading/condvar.h  \
+threading/semaphore.h threading/semaphore.c \
 threading/rwlock.h threading/rwlock.c \
 threading/lock_profiler.h \
 utils.h utils.c \

src/libstrongswan/threading/semaphore.c

@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2011 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <semaphore.h>
+
+#include <library.h>
+
+#include "semaphore.h"
+
+typedef struct private_semaphore_t private_semaphore_t;
+
+/**
+ * private data of a semaphore
+ */
+struct private_semaphore_t {
+	/**
+	 * public interface
+	 */
+	semaphore_t public;
+
+	/**
+	 * wrapped POSIX semaphore object
+	 */
+	sem_t sem;
+};
+
+METHOD(semaphore_t, wait_, void,
+	private_semaphore_t *this)
+{
+	sem_wait(&this->sem);
+}
+
+METHOD(semaphore_t, timed_wait_abs, bool,
+	private_semaphore_t *this, timeval_t tv)
+{
+	timespec_t ts;
+
+	ts.tv_sec = tv.tv_sec;
+	ts.tv_nsec = tv.tv_usec * 1000;
+
+	/* there are errors other than ETIMEDOUT possible, but we consider them
+	 * all as timeout */
+	return sem_timedwait(&this->sem, &ts) == -1;
+}
+
+METHOD(semaphore_t, timed_wait, bool,
+	private_semaphore_t *this, u_int timeout)
+{
+	timeval_t tv, add;
+
+	add.tv_sec = timeout / 1000;
+	add.tv_usec = (timeout % 1000) * 1000;
+
+	time_monotonic(&tv);
+	timeradd(&tv, &add, &tv);
+
+	return timed_wait_abs(this, tv);
+}
+
+METHOD(semaphore_t, post, void,
+	private_semaphore_t *this)
+{
+	sem_post(&this->sem);
+}
+
+METHOD(semaphore_t, destroy, void,
+	private_semaphore_t *this)
+{
+	sem_destroy(&this->sem);
+	free(this);
+}
+
+/*
+ * Described in header
+ */
+semaphore_t *semaphore_create(u_int value)
+{
+	private_semaphore_t *this;
+
+	INIT(this,
+		.public = {
+			.wait = _wait_,
+			.timed_wait = _timed_wait,
+			.timed_wait_abs = _timed_wait_abs,
+			.post = _post,
+			.destroy = _destroy,
+		},
+	);
+
+	sem_init(&this->sem, 0, value);
+
+	return &this->public;
+}
+

src/libstrongswan/threading/semaphore.h

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2011 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup semaphore semaphore
+ * @{ @ingroup threading
+ */
+
+#ifndef THREADING_SEMAPHORE_H_
+#define THREADING_SEMAPHORE_H_
+
+typedef struct semaphore_t semaphore_t;
+
+/**
+ * A semaphore is basically an integer whose value is never allowed to be
+ * lower than 0.  Two operations can be performed on it: increment the
+ * value by one, and decrement the value by one.  If the value is currently
+ * zero, then the decrement operation will blcok until the value becomes
+ * greater than zero.
+ */
+struct semaphore_t {
+
+	/**
+	 * Decrease the value by one, if it is greater than zero. Otherwise the
+	 * current thread is blocked and it waits until the value increases.
+	 */
+	void (*wait)(semaphore_t *this);
+
+	/**
+	 * Decrease the value by one, if it is greater than zero. Otherwise the
+	 * current thread is blocked and it waits until the value increases, or the
+	 * call times out.
+	 *
+	 * @param timeout		timeout im ms
+	 * @return				TRUE if timed out, FALSE otherwise
+	 */
+	bool (*timed_wait)(semaphore_t *this, u_int timeout);
+
+	/**
+	 * Decrease the value by one, if it is greater than zero. Otherwise the
+	 * current thread is blocked and it waits until the value increases, or the
+	 * call times out.
+	 *
+	 * The passed timeval should be calculated based on the time_monotonic()
+	 * function.
+	 *
+	 * @param tv			absolute time until timeout
+	 * @return				TRUE if timed out, FALSE otherwise
+	 */
+	bool (*timed_wait_abs)(semaphore_t *this, timeval_t tv);
+
+	/**
+	 * Increase the value by one. If the value becomes greater than zero, then
+	 * another thread waiting will be woken up.
+	 */
+	void (*post)(semaphore_t *this);
+
+	/**
+	 * Destroy a semaphore and free its resources.
+	 */
+	void (*destroy)(semaphore_t *this);
+};
+
+/**
+ * Create a semaphore instance.
+ *
+ * @param value		initial value (typically 0)
+ * @return			semaphore instance
+ */
+semaphore_t *semaphore_create(u_int value);
+
+#endif /** THREADING_SEMAPHORE_H_ @} */
+