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authorLars Knoll <lars.knoll@nokia.com>2009-03-23 10:18:55 +0100
committerSimon Hausmann <simon.hausmann@nokia.com>2009-03-23 10:18:55 +0100
commite5fcad302d86d316390c6b0f62759a067313e8a9 (patch)
treec2afbf6f1066b6ce261f14341cf6d310e5595bc1 /src/corelib/kernel/qsystemsemaphore_unix.cpp
Long live Qt 4.5!
Diffstat (limited to 'src/corelib/kernel/qsystemsemaphore_unix.cpp')
-rw-r--r--src/corelib/kernel/qsystemsemaphore_unix.cpp242
1 files changed, 242 insertions, 0 deletions
diff --git a/src/corelib/kernel/qsystemsemaphore_unix.cpp b/src/corelib/kernel/qsystemsemaphore_unix.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (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 either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@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 <fcntl.h>
+#include <errno.h>
+#include <sys/shm.h>
+
+#include <sys/sem.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
+
+// We have to define this as on some sem.h will have it
+union qt_semun {
+ int val; /* value for SETVAL */
+ struct semid_ds *buf; /* buffer for IPC_STAT, IPC_SET */
+ unsigned short *array; /* array for GETALL, SETALL */
+};
+
+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;
+ if (-1 == semop(semaphore, &operation, 1)) {
+ // 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