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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 QtCore 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 "qsystemsemaphore.h"
#include "qsystemsemaphore_p.h"
#include <qdebug.h>
#include <qfile.h>
#include <qcoreapplication.h>
#ifndef QT_NO_SYSTEMSEMAPHORE
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <fcntl.h>
#include <errno.h>
#include "private/qcore_unix_p.h"
// OpenBSD 4.2 doesn't define EIDRM, see BUGS section:
// http://www.openbsd.org/cgi-bin/man.cgi?query=semop&manpath=OpenBSD+4.2
#if defined(Q_OS_OPENBSD) && !defined(EIDRM)
#define EIDRM EINVAL
#endif
QT_BEGIN_NAMESPACE
QSystemSemaphorePrivate::QSystemSemaphorePrivate() :
semaphore(-1), createdFile(false),
createdSemaphore(false), unix_key(-1), error(QSystemSemaphore::NoError)
{
}
void QSystemSemaphorePrivate::setErrorString(const QString &function)
{
// EINVAL is handled in functions so they can give better error strings
switch (errno) {
case EPERM:
case EACCES:
errorString = QCoreApplication::translate("QSystemSemaphore", "%1: permission denied").arg(function);
error = QSystemSemaphore::PermissionDenied;
break;
case EEXIST:
errorString = QCoreApplication::translate("QSystemSemaphore", "%1: already exists").arg(function);
error = QSystemSemaphore::AlreadyExists;
break;
case ENOENT:
errorString = QCoreApplication::translate("QSystemSemaphore", "%1: does not exist").arg(function);
error = QSystemSemaphore::NotFound;
break;
case ERANGE:
case ENOSPC:
errorString = QCoreApplication::translate("QSystemSemaphore", "%1: out of resources").arg(function);
error = QSystemSemaphore::OutOfResources;
break;
default:
errorString = QCoreApplication::translate("QSystemSemaphore", "%1: unknown error %2").arg(function).arg(errno);
error = QSystemSemaphore::UnknownError;
#if defined QSYSTEMSEMAPHORE_DEBUG
qDebug() << errorString << "key" << key << "errno" << errno << EINVAL;
#endif
}
}
/*!
\internal
Setup unix_key
*/
key_t QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode mode)
{
if (key.isEmpty()){
errorString = QCoreApplication::tr("%1: key is empty", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle:"));
error = QSystemSemaphore::KeyError;
return -1;
}
// ftok requires that an actual file exists somewhere
if (-1 != unix_key)
return unix_key;
// Create the file needed for ftok
int built = QSharedMemoryPrivate::createUnixKeyFile(fileName);
if (-1 == built) {
errorString = QCoreApplication::tr("%1: unable to make key", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle:"));
error = QSystemSemaphore::KeyError;
return -1;
}
createdFile = (1 == built);
// Get the unix key for the created file
unix_key = ftok(QFile::encodeName(fileName).constData(), 'Q');
if (-1 == unix_key) {
errorString = QCoreApplication::tr("%1: ftok failed", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle:"));
error = QSystemSemaphore::KeyError;
return -1;
}
// Get semaphore
semaphore = semget(unix_key, 1, 0666 | IPC_CREAT | IPC_EXCL);
if (-1 == semaphore) {
if (errno == EEXIST)
semaphore = semget(unix_key, 1, 0666 | IPC_CREAT);
if (-1 == semaphore) {
setErrorString(QLatin1String("QSystemSemaphore::handle"));
cleanHandle();
return -1;
}
} else {
createdSemaphore = true;
// Force cleanup of file, it is possible that it can be left over from a crash
createdFile = true;
}
if (mode == QSystemSemaphore::Create) {
createdSemaphore = true;
createdFile = true;
}
// Created semaphore so initialize its value.
if (createdSemaphore && initialValue >= 0) {
qt_semun init_op;
init_op.val = initialValue;
if (-1 == semctl(semaphore, 0, SETVAL, init_op)) {
setErrorString(QLatin1String("QSystemSemaphore::handle"));
cleanHandle();
return -1;
}
}
return unix_key;
}
/*!
\internal
Cleanup the unix_key
*/
void QSystemSemaphorePrivate::cleanHandle()
{
unix_key = -1;
// remove the file if we made it
if (createdFile) {
QFile::remove(fileName);
createdFile = false;
}
if (createdSemaphore) {
if (-1 != semaphore) {
if (-1 == semctl(semaphore, 0, IPC_RMID, 0)) {
setErrorString(QLatin1String("QSystemSemaphore::cleanHandle"));
#if defined QSYSTEMSEMAPHORE_DEBUG
qDebug() << QLatin1String("QSystemSemaphore::cleanHandle semctl failed.");
#endif
}
semaphore = -1;
}
createdSemaphore = false;
}
}
/*!
\internal
*/
bool QSystemSemaphorePrivate::modifySemaphore(int count)
{
if (-1 == handle())
return false;
struct sembuf operation;
operation.sem_num = 0;
operation.sem_op = count;
operation.sem_flg = SEM_UNDO;
register int res;
EINTR_LOOP(res, semop(semaphore, &operation, 1));
if (-1 == res) {
// If the semaphore was removed be nice and create it and then modifySemaphore again
if (errno == EINVAL || errno == EIDRM) {
semaphore = -1;
cleanHandle();
handle();
return modifySemaphore(count);
}
setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore"));
#if defined QSYSTEMSEMAPHORE_DEBUG
qDebug() << QLatin1String("QSystemSemaphore::modify failed") << count << semctl(semaphore, 0, GETVAL) << errno << EIDRM << EINVAL;
#endif
return false;
}
return true;
}
QT_END_NAMESPACE
#endif // QT_NO_SYSTEMSEMAPHORE
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