| /**************************************************************************** |
| ** |
| ** 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 <qdir.h> |
| #include <qdebug.h> |
| |
| #include <errno.h> |
| |
| #ifndef QT_POSIX_IPC |
| |
| #ifndef QT_NO_SHAREDMEMORY |
| #include <sys/types.h> |
| #include <sys/ipc.h> |
| #include <sys/shm.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 |
| |
| /*! |
| \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 |