/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the QtCore module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** 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 Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 3 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL3 included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 3 requirements ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 2.0 or (at your option) the GNU General ** Public license version 3 or any later version approved by the KDE Free ** Qt Foundation. The licenses are as published by the Free Software ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 ** 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-2.0.html and ** https://www.gnu.org/licenses/gpl-3.0.html. ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qplatformdefs.h" #include "qsharedmemory.h" #include "qsharedmemory_p.h" #include "qsystemsemaphore.h" #include #include #include #ifndef QT_POSIX_IPC #ifndef QT_NO_SHAREDMEMORY #include #include #include #include #include #include #endif //QT_NO_SHAREDMEMORY #include "private/qcore_unix_p.h" #ifndef QT_NO_SHAREDMEMORY QT_BEGIN_NAMESPACE /*! \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 \c true if the unix file was created. -1 error 0 already existed 1 created */ int QSharedMemoryPrivate::createUnixKeyFile(const QString &fileName) { 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, 0600 | IPC_CREAT | IPC_EXCL)) { const QLatin1String function("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 ? 0400 : 0600)); 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)) { const QLatin1String function("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, 0400); 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 #endif // QT_POSIX_IPC