source: flair-src/trunk/lib/FlairCore/src/SharedMem_impl.cpp@ 4

// %flair:license{
// This file is part of the Flair framework distributed under the
// CECILL-C License, Version 1.0.
// %flair:license}
//  created:    2014/02/10
//  filename:   SharedMem_impl.cpp
//
//  author:     Guillaume Sanahuja
//              Copyright Heudiasyc UMR UTC/CNRS 7253
//
//  version:    $Id: $
//
//  purpose:    Class defining a shared memory
//
//
/*********************************************************************/

#include "SharedMem_impl.h"
#include "SharedMem.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <string.h>

using std::string;
using namespace flair::core;

SharedMem_impl::SharedMem_impl(const SharedMem* self,string name,size_t size)
{
    this->size=size;
    this->self=self;

#ifdef __XENO__
    heap_binded=false;
    int status=rt_heap_create(&heap,name.c_str(),size,H_SHARED|H_FIFO|H_NONCACHED);
    if(status==-EEXIST)
    {
        heap_binded=true;
        status=rt_heap_bind(&heap,name.c_str(),TM_INFINITE);
    }
    if(status!=0)
    {
        self->Err("rt_heap_create error (%s)\n",strerror(-status));
        return;
    }

    void *ptr;
    status=rt_heap_alloc(&heap,0,TM_NONBLOCK ,&ptr);
    if(status!=0)
    {
        self->Err("rt_heap_alloc error (%s)\n",strerror(-status));
    }
    mem_segment =(char*)ptr;

    mutex_binded=false;
    string mutex_name="mutex_"+ name;
    status=rt_mutex_create(&mutex,mutex_name.c_str());
    if(status==-EEXIST)
    {
        mutex_binded=true;
        status=rt_mutex_bind(&mutex,mutex_name.c_str(),TM_INFINITE);
    }
    if(status!=0)
    {
        self->Err("rt_mutex_create error (%s)\n",strerror(-status));
        return;
    }

#else
    shm_name="/" + name;
    fd = shm_open(shm_name.c_str(), O_RDWR | O_CREAT, 0666);
    if (fd == -1)
    {
        self->Err("Error creating shared memory\n");
    }
    ftruncate(fd, size);

    sem_name="/"  +name;
    sem = sem_open(sem_name.c_str(), O_CREAT, 0666, 1);
    if (sem == SEM_FAILED)
    {
        self->Err("Error creating semaphore\n");
    }

    mem_segment =(char*)mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (mem_segment == MAP_FAILED)
    {
        self->Err("Failed to map memory\n");
    }
#endif
}

SharedMem_impl::~SharedMem_impl()
{
    int status;
#ifdef __XENO__
    /* unnecessary because heap is opened in H_SINGLE mode
    status=rt_heap_free(&heap,mem_segment);
    if(status!=0)
    {
        self->Err("rt_heap_free error (%s)\n",strerror(-status));
    }
    */

    if(heap_binded==false)
    {
        status=rt_heap_delete(&heap);
        if(status!=0)
        {
            self->Err("rt_heap_delete error (%s)\n",strerror(-status));
        }
    }

    if(mutex_binded==false)
    {
        status=rt_mutex_delete(&mutex);
        if(status!=0)
        {
            self->Err("error destroying mutex (%s)\n",strerror(-status));
        }
    }
#else
    status = munmap(mem_segment, size);
    if(status!=0)
    {
        self->Err("Failed to unmap memory (%s)\n",strerror(-status));
    }

    status = close(fd);
    if(status!=0)
    {
        self->Err("Failed to close file (%s)\n",strerror(-status));
    }

    //do not check erros as it can be done by another process
    status = shm_unlink(shm_name.c_str());/*
    if(status!=0)
    {
        self->Err("Failed to unlink memory (%s)\n",strerror(-status));
    }
*/
    //do not check erros as it can be done by another process
    status = sem_unlink(sem_name.c_str());/*
    if(status!=0)
    {
        self->Err("Failed to unlink semaphore (%s)\n",strerror(-status));
    }*/

    status = sem_close(sem);
    if(status!=0)
    {
        self->Err("Failed to close semaphore (%s)\n",strerror(-status));
    }
#endif
}


void SharedMem_impl::Write(const char* buf,size_t size)
{
#ifdef __XENO__
    int status=rt_mutex_acquire(&mutex,TM_INFINITE);
    if(status!=0) self->Err("error (%s)\n",strerror(-status));
    memcpy(mem_segment,buf,size);
    status=rt_mutex_release(&mutex);
    if(status!=0) self->Err("error (%s)\n",strerror(-status));
#else
    sem_wait(sem);
    memcpy(mem_segment,buf,size);
    sem_post(sem);
#endif
}

void SharedMem_impl::Read(char* buf,size_t size)
{
#ifdef __XENO__
    int status=rt_mutex_acquire(&mutex,TM_INFINITE);
    if(status!=0) self->Err("error (%s)\n",strerror(-status));
    memcpy(buf,mem_segment,size);
    status=rt_mutex_release(&mutex);
    if(status!=0) self->Err("error (%s)\n",strerror(-status));
#else
    sem_wait(sem);
    memcpy(buf,mem_segment,size);
    sem_post(sem);
#endif
}