path: root/src/libstrongswan/threading/mutex.c

/*
 * Copyright (C) 2008-2009 Tobias Brunner
 * Copyright (C) 2008 Martin Willi
 * 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.
 */

#define _GNU_SOURCE
#include <pthread.h>
#include <stdint.h>
#include <time.h>
#include <errno.h>

#include <library.h>
#include <debug.h>

#include "condvar.h"
#include "mutex.h"
#include "lock_profiler.h"

typedef struct private_mutex_t private_mutex_t;
typedef struct private_r_mutex_t private_r_mutex_t;
typedef struct private_condvar_t private_condvar_t;

/**
 * private data of mutex
 */
struct private_mutex_t {

	/**
	 * public functions
	 */
	mutex_t public;

	/**
	 * wrapped pthread mutex
	 */
	pthread_mutex_t mutex;

	/**
	 * is this a recursiv emutex, implementing private_r_mutex_t?
	 */
	bool recursive;

	/**
	 * profiling info, if enabled
	 */
	lock_profile_t profile;
};

/**
 * private data of mutex, extended by recursive locking information
 */
struct private_r_mutex_t {

	/**
	 * Extends private_mutex_t
	 */
	private_mutex_t generic;

	/**
	 * thread which currently owns mutex
	 */
	pthread_t thread;

	/**
	 * times we have locked the lock, stored per thread
	 */
	pthread_key_t times;
};

/**
 * private data of condvar
 */
struct private_condvar_t {

	/**
	 * public functions
	 */
	condvar_t public;

	/**
	 * wrapped pthread condvar
	 */
	pthread_cond_t condvar;

};



/**
 * Implementation of mutex_t.lock.
 */
static void lock(private_mutex_t *this)
{
	int err;

	profiler_start(&this->profile);
	err = pthread_mutex_lock(&this->mutex);
	if (err)
	{
		DBG1(DBG_LIB, "!!! MUTEX LOCK ERROR: %s !!!", strerror(err));
	}
	profiler_end(&this->profile);
}

/**
 * Implementation of mutex_t.unlock.
 */
static void unlock(private_mutex_t *this)
{
	int err;

	err = pthread_mutex_unlock(&this->mutex);
	if (err)
	{
		DBG1(DBG_LIB, "!!! MUTEX UNLOCK ERROR: %s !!!", strerror(err));
	}
}

/**
 * Implementation of mutex_t.lock.
 */
static void lock_r(private_r_mutex_t *this)
{
	pthread_t self = pthread_self();

	if (this->thread == self)
	{
		uintptr_t times;

		/* times++ */
		times = (uintptr_t)pthread_getspecific(this->times);
		pthread_setspecific(this->times, (void*)times + 1);
	}
	else
	{
		lock(&this->generic);
		this->thread = self;
		/* times = 1 */
		pthread_setspecific(this->times, (void*)1);
	}
}

/**
 * Implementation of mutex_t.unlock.
 */
static void unlock_r(private_r_mutex_t *this)
{
	uintptr_t times;

	/* times-- */
	times = (uintptr_t)pthread_getspecific(this->times);
	pthread_setspecific(this->times, (void*)--times);

	if (times == 0)
	{
		this->thread = 0;
		unlock(&this->generic);
	}
}

/**
 * Implementation of mutex_t.destroy
 */
static void mutex_destroy(private_mutex_t *this)
{
	profiler_cleanup(&this->profile);
	pthread_mutex_destroy(&this->mutex);
	free(this);
}

/**
 * Implementation of mutex_t.destroy for recursive mutex'
 */
static void mutex_destroy_r(private_r_mutex_t *this)
{
	profiler_cleanup(&this->generic.profile);
	pthread_mutex_destroy(&this->generic.mutex);
	pthread_key_delete(this->times);
	free(this);
}

/*
 * see header file
 */
mutex_t *mutex_create(mutex_type_t type)
{
	switch (type)
	{
		case MUTEX_TYPE_RECURSIVE:
		{
			private_r_mutex_t *this = malloc_thing(private_r_mutex_t);

			this->generic.public.lock = (void(*)(mutex_t*))lock_r;
			this->generic.public.unlock = (void(*)(mutex_t*))unlock_r;
			this->generic.public.destroy = (void(*)(mutex_t*))mutex_destroy_r;

			pthread_mutex_init(&this->generic.mutex, NULL);
			pthread_key_create(&this->times, NULL);
			this->generic.recursive = TRUE;
			profiler_init(&this->generic.profile);
			this->thread = 0;

			return &this->generic.public;
		}
		case MUTEX_TYPE_DEFAULT:
		default:
		{
			private_mutex_t *this = malloc_thing(private_mutex_t);

			this->public.lock = (void(*)(mutex_t*))lock;
			this->public.unlock = (void(*)(mutex_t*))unlock;
			this->public.destroy = (void(*)(mutex_t*))mutex_destroy;

			pthread_mutex_init(&this->mutex, NULL);
			this->recursive = FALSE;
			profiler_init(&this->profile);

			return &this->public;
		}
	}
}



/**
 * Implementation of condvar_t.wait.
 */
static void _wait(private_condvar_t *this, private_mutex_t *mutex)
{
	if (mutex->recursive)
	{
		private_r_mutex_t* recursive = (private_r_mutex_t*)mutex;

		/* mutex owner gets cleared during condvar wait */
		recursive->thread = 0;
		pthread_cond_wait(&this->condvar, &mutex->mutex);
		recursive->thread = pthread_self();
	}
	else
	{
		pthread_cond_wait(&this->condvar, &mutex->mutex);
	}
}

/* use the monotonic clock based version of this function if available */
#ifdef HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
#define pthread_cond_timedwait pthread_cond_timedwait_monotonic
#endif

/**
 * Implementation of condvar_t.timed_wait_abs.
 */
static bool timed_wait_abs(private_condvar_t *this, private_mutex_t *mutex,
						   timeval_t time)
{
	struct timespec ts;
	bool timed_out;

	ts.tv_sec = time.tv_sec;
	ts.tv_nsec = time.tv_usec * 1000;

	if (mutex->recursive)
	{
		private_r_mutex_t* recursive = (private_r_mutex_t*)mutex;

		recursive->thread = 0;
		timed_out = pthread_cond_timedwait(&this->condvar, &mutex->mutex,
										   &ts) == ETIMEDOUT;
		recursive->thread = pthread_self();
	}
	else
	{
		timed_out = pthread_cond_timedwait(&this->condvar, &mutex->mutex,
										   &ts) == ETIMEDOUT;
	}
	return timed_out;
}

/**
 * Implementation of condvar_t.timed_wait.
 */
static bool timed_wait(private_condvar_t *this, private_mutex_t *mutex,
					   u_int timeout)
{
	timeval_t tv;
	u_int s, ms;

	time_monotonic(&tv);

	s = timeout / 1000;
	ms = timeout % 1000;

	tv.tv_sec += s;
	tv.tv_usec += ms * 1000;

	if (tv.tv_usec > 1000000 /* 1s */)
	{
		tv.tv_usec -= 1000000;
		tv.tv_sec++;
	}
	return timed_wait_abs(this, mutex, tv);
}

/**
 * Implementation of condvar_t.signal.
 */
static void _signal(private_condvar_t *this)
{
	pthread_cond_signal(&this->condvar);
}

/**
 * Implementation of condvar_t.broadcast.
 */
static void broadcast(private_condvar_t *this)
{
	pthread_cond_broadcast(&this->condvar);
}

/**
 * Implementation of condvar_t.destroy
 */
static void condvar_destroy(private_condvar_t *this)
{
	pthread_cond_destroy(&this->condvar);
	free(this);
}

/*
 * see header file
 */
condvar_t *condvar_create(condvar_type_t type)
{
	switch (type)
	{
		case CONDVAR_TYPE_DEFAULT:
		default:
		{
			private_condvar_t *this = malloc_thing(private_condvar_t);

			this->public.wait = (void(*)(condvar_t*, mutex_t *mutex))_wait;
			this->public.timed_wait = (bool(*)(condvar_t*, mutex_t *mutex, u_int timeout))timed_wait;
			this->public.timed_wait_abs = (bool(*)(condvar_t*, mutex_t *mutex, timeval_t time))timed_wait_abs;
			this->public.signal = (void(*)(condvar_t*))_signal;
			this->public.broadcast = (void(*)(condvar_t*))broadcast;
			this->public.destroy = (void(*)(condvar_t*))condvar_destroy;

#ifdef HAVE_PTHREAD_CONDATTR_INIT
			{
				pthread_condattr_t condattr;
				pthread_condattr_init(&condattr);
#ifdef HAVE_CONDATTR_CLOCK_MONOTONIC
				pthread_condattr_setclock(&condattr, CLOCK_MONOTONIC);
#endif
				pthread_cond_init(&this->condvar, &condattr);
				pthread_condattr_destroy(&condattr);
			}
#endif

			return &this->public;
		}
	}
}