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Diffstat (limited to 'src/corelib/kernel/qsharedmemory_unix.cpp')
-rw-r--r-- | src/corelib/kernel/qsharedmemory_unix.cpp | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/src/corelib/kernel/qsharedmemory_unix.cpp b/src/corelib/kernel/qsharedmemory_unix.cpp new file mode 100644 index 0000000000..b30117f6c1 --- /dev/null +++ b/src/corelib/kernel/qsharedmemory_unix.cpp @@ -0,0 +1,302 @@ +/**************************************************************************** +** +** 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 "qplatformdefs.h" + +#include "qsharedmemory.h" +#include "qsharedmemory_p.h" +#include "qsystemsemaphore.h" +#include <qdir.h> +#include <qdebug.h> + +#include <errno.h> + +#ifndef QT_NO_SHAREDMEMORY +#include <sys/types.h> +#include <sys/ipc.h> +#include <sys/shm.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> +#endif //QT_NO_SHAREDMEMORY + +#include "private/qcore_unix_p.h" + +#ifndef QT_NO_SHAREDMEMORY +QT_BEGIN_NAMESPACE + +QSharedMemoryPrivate::QSharedMemoryPrivate() + : QObjectPrivate(), memory(0), size(0), error(QSharedMemory::NoError), +#ifndef QT_NO_SYSTEMSEMAPHORE + systemSemaphore(QString()), lockedByMe(false), +#endif + unix_key(0) +{ +} + +void QSharedMemoryPrivate::setErrorString(const QString &function) +{ + // EINVAL is handled in functions so they can give better error strings + switch (errno) { + case EACCES: + errorString = QSharedMemory::tr("%1: permission denied").arg(function); + error = QSharedMemory::PermissionDenied; + break; + case EEXIST: + errorString = QSharedMemory::tr("%1: already exists").arg(function); + error = QSharedMemory::AlreadyExists; + break; + case ENOENT: + errorString = QSharedMemory::tr("%1: doesn't exist").arg(function); + error = QSharedMemory::NotFound; + break; + case EMFILE: + case ENOMEM: + case ENOSPC: + errorString = QSharedMemory::tr("%1: out of resources").arg(function); + error = QSharedMemory::OutOfResources; + break; + default: + errorString = QSharedMemory::tr("%1: unknown error %2").arg(function).arg(errno); + error = QSharedMemory::UnknownError; +#if defined QSHAREDMEMORY_DEBUG + qDebug() << errorString << "key" << key << "errno" << errno << EINVAL; +#endif + } +} + +/*! + \internal + + If not already made create the handle used for accessing the shared memory. +*/ +key_t QSharedMemoryPrivate::handle() +{ + // already made + if (unix_key) + return unix_key; + + // don't allow making handles on empty keys + if (nativeKey.isEmpty()) { + errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle:")); + error = QSharedMemory::KeyError; + return 0; + } + + // ftok requires that an actual file exists somewhere + if (!QFile::exists(nativeKey)) { + errorString = QSharedMemory::tr("%1: UNIX key file doesn't exist").arg(QLatin1String("QSharedMemory::handle:")); + error = QSharedMemory::NotFound; + return 0; + } + + unix_key = ftok(QFile::encodeName(nativeKey).constData(), 'Q'); + if (-1 == unix_key) { + errorString = QSharedMemory::tr("%1: ftok failed").arg(QLatin1String("QSharedMemory::handle:")); + error = QSharedMemory::KeyError; + unix_key = 0; + } + return unix_key; +} + +#endif // QT_NO_SHAREDMEMORY + +#if !(defined(QT_NO_SHAREDMEMORY) && defined(QT_NO_SYSTEMSEMAPHORE)) +/*! + \internal + Creates the unix file if needed. + returns true if the unix file was created. + + -1 error + 0 already existed + 1 created + */ +int QSharedMemoryPrivate::createUnixKeyFile(const QString &fileName) +{ + if (QFile::exists(fileName)) + return 0; + + int fd = qt_safe_open(QFile::encodeName(fileName).constData(), + O_EXCL | O_CREAT | O_RDWR, 0640); + if (-1 == fd) { + if (errno == EEXIST) + return 0; + return -1; + } else { + close(fd); + } + return 1; +} +#endif // QT_NO_SHAREDMEMORY && QT_NO_SYSTEMSEMAPHORE + +#ifndef QT_NO_SHAREDMEMORY + +bool QSharedMemoryPrivate::cleanHandle() +{ + unix_key = 0; + return true; +} + +bool QSharedMemoryPrivate::create(int size) +{ + // build file if needed + bool createdFile = false; + int built = createUnixKeyFile(nativeKey); + if (built == -1) { + errorString = QSharedMemory::tr("%1: unable to make key").arg(QLatin1String("QSharedMemory::handle:")); + error = QSharedMemory::KeyError; + return false; + } + if (built == 1) { + createdFile = true; + } + + // get handle + if (!handle()) { + if (createdFile) + QFile::remove(nativeKey); + return false; + } + + // create + if (-1 == shmget(unix_key, size, 0666 | IPC_CREAT | IPC_EXCL)) { + QString function = QLatin1String("QSharedMemory::create"); + switch (errno) { + case EINVAL: + errorString = QSharedMemory::tr("%1: system-imposed size restrictions").arg(QLatin1String("QSharedMemory::handle")); + error = QSharedMemory::InvalidSize; + break; + default: + setErrorString(function); + } + if (createdFile && error != QSharedMemory::AlreadyExists) + QFile::remove(nativeKey); + return false; + } + + return true; +} + +bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode) +{ + // grab the shared memory segment id + int id = shmget(unix_key, 0, (mode == QSharedMemory::ReadOnly ? 0444 : 0660)); + if (-1 == id) { + setErrorString(QLatin1String("QSharedMemory::attach (shmget)")); + return false; + } + + // grab the memory + memory = shmat(id, 0, (mode == QSharedMemory::ReadOnly ? SHM_RDONLY : 0)); + if ((void*) - 1 == memory) { + memory = 0; + setErrorString(QLatin1String("QSharedMemory::attach (shmat)")); + return false; + } + + // grab the size + shmid_ds shmid_ds; + if (!shmctl(id, IPC_STAT, &shmid_ds)) { + size = (int)shmid_ds.shm_segsz; + } else { + setErrorString(QLatin1String("QSharedMemory::attach (shmctl)")); + return false; + } + + return true; +} + +bool QSharedMemoryPrivate::detach() +{ + // detach from the memory segment + if (-1 == shmdt(memory)) { + QString function = QLatin1String("QSharedMemory::detach"); + switch (errno) { + case EINVAL: + errorString = QSharedMemory::tr("%1: not attached").arg(function); + error = QSharedMemory::NotFound; + break; + default: + setErrorString(function); + } + return false; + } + memory = 0; + size = 0; + + // Get the number of current attachments + int id = shmget(unix_key, 0, 0444); + cleanHandle(); + + struct shmid_ds shmid_ds; + if (0 != shmctl(id, IPC_STAT, &shmid_ds)) { + switch (errno) { + case EINVAL: + return true; + default: + return false; + } + } + // If there are no attachments then remove it. + if (shmid_ds.shm_nattch == 0) { + // mark for removal + if (-1 == shmctl(id, IPC_RMID, &shmid_ds)) { + setErrorString(QLatin1String("QSharedMemory::remove")); + switch (errno) { + case EINVAL: + return true; + default: + return false; + } + } + + // remove file + if (!QFile::remove(nativeKey)) + return false; + } + return true; +} + + +QT_END_NAMESPACE + +#endif // QT_NO_SHAREDMEMORY |