diff options
Diffstat (limited to 'src/corelib/kernel/qsystemsemaphore_systemv.cpp')
| -rw-r--r-- | src/corelib/kernel/qsystemsemaphore_systemv.cpp | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/src/corelib/kernel/qsystemsemaphore_systemv.cpp b/src/corelib/kernel/qsystemsemaphore_systemv.cpp new file mode 100644 index 0000000000..f212f5e49f --- /dev/null +++ b/src/corelib/kernel/qsystemsemaphore_systemv.cpp @@ -0,0 +1,198 @@ +/**************************************************************************** +** +** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL21$ +** 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 Digia. For licensing terms and +** conditions see http://qt.digia.com/licensing. For further information +** use the contact form at http://qt.digia.com/contact-us. +** +** 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 or version 3 as published by the Free +** Software Foundation and appearing in the file LICENSE.LGPLv21 and +** LICENSE.LGPLv3 included in the packaging of this file. Please review the +** following information to ensure the GNU Lesser General Public License +** requirements will be met: https://www.gnu.org/licenses/lgpl.html and +** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Digia gives you certain additional +** rights. These rights are described in the Digia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qsystemsemaphore.h" +#include "qsystemsemaphore_p.h" + +#include <qdebug.h> +#include <qfile.h> +#include <qcoreapplication.h> + +#ifndef QT_POSIX_IPC + +#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 + +/*! + \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, 0600 | IPC_CREAT | IPC_EXCL); + if (-1 == semaphore) { + if (errno == EEXIST) + semaphore = semget(unix_key, 1, 0600 | 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; + + 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; + } + + clearError(); + return true; +} + + +QT_END_NAMESPACE + +#endif // QT_NO_SYSTEMSEMAPHORE + +#endif // QT_POSIX_IPC |