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/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qwssharedmemory_p.h"
#if !defined(QT_NO_QWS_MULTIPROCESS)
#include <sys/shm.h>
QT_BEGIN_NAMESPACE
QWSSharedMemory::QWSSharedMemory()
: shmBase(0), shmSize(0), character(0), shmId(-1), key(-1)
{
}
QWSSharedMemory::~QWSSharedMemory()
{
detach();
}
/*
man page says:
On Linux, it is possible to attach a shared memory segment even if it
is already marked to be deleted. However, POSIX.1-2001 does not spec-
ify this behaviour and many other implementations do not support it.
*/
bool QWSSharedMemory::create(int size)
{
if (shmId != -1)
detach();
shmId = shmget(IPC_PRIVATE, size, IPC_CREAT|0600);
if (shmId == -1) {
#ifdef QT_SHM_DEBUG
perror("QWSSharedMemory::create allocating shared memory");
qWarning("Error allocating shared memory of size %d", size);
#endif
return false;
}
shmBase = shmat(shmId,0,0);
shmctl(shmId, IPC_RMID, 0);
if (shmBase == (void*)-1) {
#ifdef QT_SHM_DEBUG
perror("QWSSharedMemory::create attaching to shared memory");
qWarning("Error attaching to shared memory id %d", shmId);
#endif
shmBase = 0;
return false;
}
return true;
}
bool QWSSharedMemory::attach(int id)
{
if (shmId == id)
return id != -1;
if (shmId != -1)
detach();
shmBase = shmat(id,0,0);
if (shmBase == (void*)-1) {
#ifdef QT_SHM_DEBUG
perror("QWSSharedMemory::attach attaching to shared memory");
qWarning("Error attaching to shared memory 0x%x of size %d",
id, size());
#endif
shmBase = 0;
return false;
}
shmId = id;
return true;
}
void QWSSharedMemory::detach ()
{
if (!shmBase)
return;
shmdt (shmBase);
shmBase = 0;
shmSize = 0;
shmId = -1;
}
void QWSSharedMemory::setPermissions (mode_t mode)
{
struct shmid_ds shm;
shmctl (shmId, IPC_STAT, &shm);
shm.shm_perm.mode = mode;
shmctl (shmId, IPC_SET, &shm);
}
int QWSSharedMemory::size () const
{
struct shmid_ds shm;
shmctl (shmId, IPC_STAT, &shm);
return shm.shm_segsz;
}
// old API
QWSSharedMemory::QWSSharedMemory (int size, const QString &filename, char c)
{
shmSize = size;
shmFile = filename;
shmBase = 0;
shmId = -1;
character = c;
key = ftok (shmFile.toLatin1().constData(), c);
}
bool QWSSharedMemory::create ()
{
shmId = shmget (key, shmSize, IPC_CREAT | 0666);
return (shmId != -1);
}
void QWSSharedMemory::destroy ()
{
if (shmId != -1)
shmctl(shmId, IPC_RMID, 0);
}
bool QWSSharedMemory::attach ()
{
if (shmId == -1)
shmId = shmget (key, shmSize, 0);
shmBase = shmat (shmId, 0, 0);
if ((long)shmBase == -1)
shmBase = 0;
return (long)shmBase != 0;
}
QT_END_NAMESPACE
#endif // QT_NO_QWS_MULTIPROCESS
|
