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/****************************************************************************
**
** Copyright (C) 2013 Klaralvdalens Datakonsult AB (KDAB)
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Installer Framework.
**
** $QT_BEGIN_LICENSE:GPL-EXCEPT$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "lockfile_p.h"
#include <QCoreApplication>
#include <QDir>
#include <cerrno>
#include <sys/file.h>
#include <unistd.h>
namespace KDUpdater {
bool LockFile::Private::lock()
{
if (locked)
return true;
errorString.clear();
errno = 0;
handle = open(filename.toLatin1().constData(), O_CREAT | O_RDWR | O_NONBLOCK, 0600);
if (handle == -1) {
errorString = QCoreApplication::translate("LockFile", "Cannot create lock file \"%1\": "
"%2").arg(QDir::toNativeSeparators(filename), QString::fromLocal8Bit(strerror(errno)));
return false;
}
const QString pid = QString::number(qApp->applicationPid());
const QByteArray data = pid.toLatin1();
errno = 0;
qint64 written = 0;
while (written < data.size()) {
const qint64 n = write(handle, data.constData() + written, data.size() - written);
if (n < 0) {
errorString = QCoreApplication::translate("LockFile", "Cannot write PID to lock "
"file \"%1\": %2").arg(QDir::toNativeSeparators(filename), QString::fromLocal8Bit(strerror(errno)));
return false;
}
written += n;
}
errno = 0;
locked = flock(handle, LOCK_NB | LOCK_EX) != -1;
if (!locked) {
errorString = QCoreApplication::translate("LockFile", "Cannot obtain the lock for "
"file \"%1\": %2").arg(QDir::toNativeSeparators(filename), QString::fromLocal8Bit(strerror(errno)));
}
return locked;
}
bool LockFile::Private::unlock()
{
errorString.clear();
if (!locked)
return true;
errno = 0;
locked = flock(handle, LOCK_UN | LOCK_NB) == -1;
if (locked) {
errorString = QCoreApplication::translate("LockFile", "Cannot release the lock for "
"file \"%1\": %2").arg(QDir::toNativeSeparators(filename), QString::fromLocal8Bit(strerror(errno)));
} else {
unlink(filename.toLatin1());
}
return !locked;
}
} // namespace KDUpdater
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