Semaphore.cpp

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// Copyright CERN 2012 - Developed in collaboration with GSI

#include <fesa-core/Utilities/Semaphore.h>

#include <fesa-core/Utilities/StringUtilities.h>
#include <fesa-core/Exception/FesaException.h>

#include <iostream>
#include <cerrno>
#include <sys/stat.h>
#include <fcntl.h>


namespace fesa
{

Semaphore::Semaphore(const std::string& semaphoreName, int32_t value)
{
    std::string errorNumber;
    semaphoreName_ = semaphoreName;
    int32_t org_mask = umask(0); // set the user mask to 0 in order to create the semaphore with the wanted rights
    semaphore_ = sem_open(semaphoreName_.c_str(), O_CREAT, 0666, value);
    umask(org_mask);   // restore the user mask
    if (semaphore_ == SEM_FAILED)
    {
        errorNumber = StringUtilities::toString(errno);
        throw FesaException(__FILE__, __LINE__, FesaErrorOpeningSemaphore.c_str(), errorNumber.c_str());
    }
}

Semaphore::~Semaphore()
{
    std::string errorNumber;
    if (sem_close(semaphore_) == 0)
        sem_unlink(semaphoreName_.c_str());

}

void Semaphore::wait()
{
    std::string errorNumber;

    if (sem_wait(semaphore_) == -1)
    {
        errorNumber = StringUtilities::toString(errno);
        throw FesaException(__FILE__, __LINE__, FesaErrorWaitingForSemaphore.c_str(), errorNumber.c_str());
    }
}

int32_t Semaphore::tryWait()
{
    std::string errorNumber;
    if (sem_trywait(semaphore_) == -1)
    {
        if (errno != EAGAIN)
        {
            errorNumber = StringUtilities::toString(errno);
            throw FesaException(__FILE__, __LINE__, FesaErrorTryWaitingForSemaphore.c_str(), errorNumber.c_str());
        }
        return -1;
    }
    return 0;
}

int32_t Semaphore::timedWait(const struct timespec* abs_timeout)
{
    std::string errorNumber;
    int32_t err;
    //      std::cout << "Sem value " << this->getValue() << std::endl;
    err = sem_timedwait(semaphore_, abs_timeout);
    if (err != 0)
    {
        throw FesaException(__FILE__, __LINE__, FesaErrorTryWaitingForSemaphore.c_str(), errorNumber.c_str());
        return -1;
    }
    return 0;
}

void Semaphore::post()
{
    std::string errorNumber;
    if (sem_post(semaphore_) == -1)
    {
        errorNumber = StringUtilities::toString(errno);
        throw FesaException(__FILE__, __LINE__, FesaErrorPostingSemaphore.c_str(), errorNumber.c_str());
    }
}

int32_t Semaphore::getValue()
{
    std::string errorNumber;
    int32_t value;
    if (sem_getvalue(semaphore_, &value) == 0)
    {
        return value;
    }
    else
    {
        errorNumber = StringUtilities::toString(errno);
        throw FesaException(__FILE__, __LINE__, FesaErrorGettingValueOfSemaphore.c_str(), errorNumber.c_str());
    }
    return -1;
}

} // fesa