rts/umlrt/umlrtmutex.cc

// umlrtmutex.cc

/*******************************************************************************
* Copyright (c) 2014-2015 Zeligsoft (2009) Limited  and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*******************************************************************************/


#include <errno.h>
#include <time.h>
#include "basefatal.hh"
#include "umlrtmutex.hh"
#include "umlrttimespec.hh"

// UMLRTMutex is platform-independent mutual-exclusion.

// Bug 32 tracks the move of this implementation to +/os/linux/osmutex.cc

UMLRTMutex::UMLRTMutex()
{
    pthread_mutex_init(&mutex, NULL);
}

// Can create a mutex which starts life as taken already.
UMLRTMutex::UMLRTMutex( bool taken )
{
    if (taken)
    {
        take();
    }
}

UMLRTMutex::~UMLRTMutex()
{
    pthread_mutex_destroy(&mutex);
}
// Wait forever for mutex.
void UMLRTMutex::take()
{
    if (pthread_mutex_lock(&mutex) < 0)
    {
        FATAL_ERRNO("pthread_mutex_lock");
    }
}

// Timed - returns non-zero for success, zero for timeout.
#if (((__GNUC__ * 100) + __GNUC_MINOR__) >= 406)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif

int UMLRTMutex::take( uint32_t msec )
{
    struct timespec timeout;
    int success = !0;

    UMLRTTimespec::timespecAbsAddMsec( &timeout, msec );
    if (pthread_mutex_timedlock(&mutex, &timeout) < 0)
    {
        int errno_ = errno;
        if (errno_ != ETIMEDOUT)
        {
            FATAL_ERRNO("pthread_mutex_timedlock");
        }
        success = 0;
    }
    return success;
}
#if (((__GNUC__ * 100) + __GNUC_MINOR__) >= 406)
#pragma GCC diagnostic pop
#endif

// Give mutex back.
void UMLRTMutex::give()
{
    if (pthread_mutex_unlock(&mutex) < 0)
    {
        FATAL_ERRNO("pthread_mutex_unlock");
    }
}