tqt3/src/kernel/qsharedmemory_p.cpp

/****************************************************************************
**
** Provides a standardised interface to shared memory
**
** Created : 020124
**
** Copyright (C) 1992-2008 Trolltech ASA.  All rights reserved.
**
** This file is part of the kernel module of the TQt GUI Toolkit.
**
** This file may be used under the terms of the GNU General
** Public License versions 2.0 or 3.0 as published by the Free
** Software Foundation and appearing in the files LICENSE.GPL2
** and LICENSE.GPL3 included in the packaging of this file.
** Alternatively you may (at your option) use any later version
** of the GNU General Public License if such license has been
** publicly approved by Trolltech ASA (or its successors, if any)
** and the KDE Free TQt Foundation.
**
** Please review the following information to ensure GNU General
** Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/.
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at sales@trolltech.com.
**
** Licensees holding valid TQt Commercial licenses may use this file in
** accordance with the TQt Commercial License Agreement provided with
** the Software.
**
** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
** herein.
**
**********************************************************************/

#include "qsharedmemory_p.h"

#if !defined(QT_QWS_NO_SHM)

#if defined(QT_POSIX_QSHM)
#include <fcntl.h>
#include <sys/mman.h>

TQSharedMemory::TQSharedMemory (int size, TQString filename, char c )
{
  shmSize = size;
  shmFile = filename;
  character = c;
  shmFile.append(c);
}

bool TQSharedMemory::create ()
{
  shmFD = shm_open (shmFile.latin1 (), O_RDWR | O_EXCL | O_CREAT, 0666);
  if (shmFD == -1)
    return FALSE;
  else if (ftruncate (shmFD, shmSize) == -1)
    {
      close (shmFD);
      return FALSE;
    }

  return TRUE;
}

void TQSharedMemory::destroy ()
{
  shm_unlink (shmFile.latin1 ());
}

bool TQSharedMemory::attach ()
{
  shmBase = mmap (0, shmSize, PROT_READ | PROT_WRITE, MAP_SHARED, shmFD, 0);

  if (shmBase == MAP_FAILED)
    return FALSE;

  close (shmFD);
  return TRUE;
}

void TQSharedMemory::detach ()
{
  munmap (shmBase, shmSize);
}

void TQSharedMemory::setPermissions (mode_t mode)
{
  mprotect (shmBase, shmSize, mode);	// Provide defines to make prot work properly
}

int TQSharedMemory::size()
{
    struct stat buf;
    int rc = fstat (shmFD, &buf);
    if (rc != -1)
        return buf.st_size;
    else
        return rc;
}

#else // Assume SysV for backwards compat
#include <sys/shm.h>

TQSharedMemory::TQSharedMemory (int size, TQString filename, char c )
{
  shmSize = size;
  shmFile = filename;
  character = c;
  key = ftok (shmFile.latin1 (), c);
  idInitted = FALSE;
  shmId = -1;
}

bool TQSharedMemory::create ()
{
  shmId = shmget (key, shmSize, IPC_CREAT | 0666);
  if (shmId == -1)
    return FALSE;
  else
    return TRUE;
}

void TQSharedMemory::destroy ()
{
    if (shmId != -1) {
        struct shmid_ds shm;
        shmctl (shmId, IPC_RMID, &shm);
    }
}

bool TQSharedMemory::attach ()
{
  if (shmId == -1)
    shmId = shmget (key, shmSize, 0);

  shmBase = shmat (shmId, 0, 0);
  if ((int) shmBase == -1 || shmBase == 0)
    return FALSE;
  else
    return TRUE;
}

void TQSharedMemory::detach ()
{
  shmdt (shmBase);
}

void TQSharedMemory::setPermissions (mode_t mode)
{
  struct shmid_ds shm;
  shmctl (shmId, IPC_STAT, &shm);
  shm.shm_perm.mode = mode;
  shmctl (shmId, IPC_SET, &shm);
}

int TQSharedMemory::size ()
{
    struct shmid_ds shm;
    shmctl (shmId, IPC_STAT, &shm);
    return shm.shm_segsz;
}

#endif

#endif