source: XMLIO_V2/external/src/POCO/Foundation.save/SharedMemory_POSIX.cpp @ 80

//
// SharedMemoryImpl.cpp
//
// $Id: //poco/1.3/Foundation/src/SharedMemory_POSIX.cpp#2 $
//
// Library: Foundation
// Package: Processes
// Module:  SharedMemoryImpl
//
// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#include "Poco/SharedMemory_POSIX.h"
#include "Poco/Exception.h"
#include "Poco/File.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>


namespace Poco {


SharedMemoryImpl::SharedMemoryImpl(const std::string& name, std::size_t size, SharedMemory::AccessMode mode, const void* addrHint, bool server):
        _size(size),
        _fd(-1),
        _address(0),
        _access(mode),
        _name("/"),
        _fileMapped(false),
        _server(server)
{
#if POCO_OS == POCO_OS_HPUX
        _name.append("tmp/");
#endif

        _name.append(name);

        int flags = O_CREAT;
        if (_access == SharedMemory::AM_WRITE)
                flags |= O_RDWR;
        else
                flags |= O_RDONLY;

        // open the shared memory segment
        _fd = ::shm_open(_name.c_str(), flags, S_IRUSR | S_IWUSR);
        if (_fd == -1)
                throw SystemException("Cannot create shared memory object", _name);

        // now set the correct size for the segment
        if (-1 == ::ftruncate(_fd, size))
        {
                ::close(_fd);
                _fd = -1;
                ::shm_unlink(_name.c_str());
                throw SystemException("Cannot resize shared memory object", _name);
        }
        map(addrHint);
}


SharedMemoryImpl::SharedMemoryImpl(const Poco::File& file, SharedMemory::AccessMode mode, const void* addrHint):
        _size(0),
        _fd(-1),
        _address(0),
        _access(mode),
        _name(file.path()),
        _fileMapped(true),
        _server(false)
{
        if (!file.exists() || !file.isFile())
                throw FileNotFoundException(file.path());

        _size = file.getSize();
        int flag = O_RDONLY;
        if (mode == SharedMemory::AM_WRITE)
                flag = O_RDWR;
        _fd = ::open(_name.c_str(), flag);
        if (-1 == _fd)
                throw OpenFileException("Cannot open memory mapped file", _name);

        map(addrHint);
}


SharedMemoryImpl::~SharedMemoryImpl()
{
        unmap();
        close();
}


void SharedMemoryImpl::map(const void* addrHint)
{
        int access = PROT_READ;
        if (_access == SharedMemory::AM_WRITE)
                access |= PROT_WRITE;

        void* addr = ::mmap(const_cast<void*>(addrHint), _size, access, MAP_SHARED, _fd, 0);
        if (addr == MAP_FAILED)
                throw SystemException("Cannot map file into shared memory", _name);

        _address = static_cast<char*>(addr);
}


void SharedMemoryImpl::unmap()
{
        if (_address)
        {
                ::munmap(_address, _size);
        }
}


void SharedMemoryImpl::close()
{
        if (_fd != -1)
        {
                ::close(_fd);
                _fd = -1;
        }
        if (!_fileMapped && _server)
        {
                ::shm_unlink(_name.c_str());
        }
}


} // namespace Poco