| /**************************************************************************** |
| ** |
| ** Copyright (C) 2015 Konstantin Ritt <ritt.ks@gmail.com> |
| ** Copyright (C) 2016 The Qt Company Ltd. |
| ** Copyright (C) 2015 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Tobias Koenig <tobias.koenig@kdab.com> |
| ** 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 <qfile.h> |
| |
| #include <errno.h> |
| |
| #ifdef QT_POSIX_IPC |
| |
| #ifndef QT_NO_SHAREDMEMORY |
| #include <sys/types.h> |
| #include <sys/mman.h> |
| #include <sys/stat.h> |
| #include <fcntl.h> |
| #include <unistd.h> |
| |
| #include "private/qcore_unix_p.h" |
| |
| QT_BEGIN_NAMESPACE |
| |
| int QSharedMemoryPrivate::handle() |
| { |
| // don't allow making handles on empty keys |
| const QString safeKey = makePlatformSafeKey(key); |
| if (safeKey.isEmpty()) { |
| errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle")); |
| error = QSharedMemory::KeyError; |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| bool QSharedMemoryPrivate::cleanHandle() |
| { |
| qt_safe_close(hand); |
| hand = -1; |
| |
| return true; |
| } |
| |
| bool QSharedMemoryPrivate::create(int size) |
| { |
| if (!handle()) |
| return false; |
| |
| const QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key)); |
| |
| int fd; |
| #ifdef O_CLOEXEC |
| // First try with O_CLOEXEC flag, if that fails, fall back to normal flags |
| EINTR_LOOP(fd, ::shm_open(shmName.constData(), O_RDWR | O_CREAT | O_EXCL | O_CLOEXEC, 0600)); |
| if (fd == -1) |
| EINTR_LOOP(fd, ::shm_open(shmName.constData(), O_RDWR | O_CREAT | O_EXCL, 0600)); |
| #else |
| EINTR_LOOP(fd, ::shm_open(shmName.constData(), O_RDWR | O_CREAT | O_EXCL, 0600)); |
| #endif |
| if (fd == -1) { |
| const int errorNumber = errno; |
| const QLatin1String function("QSharedMemory::attach (shm_open)"); |
| switch (errorNumber) { |
| case ENAMETOOLONG: |
| case EINVAL: |
| errorString = QSharedMemory::tr("%1: bad name").arg(function); |
| error = QSharedMemory::KeyError; |
| break; |
| default: |
| setErrorString(function); |
| } |
| return false; |
| } |
| |
| // the size may only be set once |
| int ret; |
| EINTR_LOOP(ret, QT_FTRUNCATE(fd, size)); |
| if (ret == -1) { |
| setErrorString(QLatin1String("QSharedMemory::create (ftruncate)")); |
| qt_safe_close(fd); |
| return false; |
| } |
| |
| qt_safe_close(fd); |
| |
| return true; |
| } |
| |
| bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode) |
| { |
| const QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key)); |
| |
| const int oflag = (mode == QSharedMemory::ReadOnly ? O_RDONLY : O_RDWR); |
| const mode_t omode = (mode == QSharedMemory::ReadOnly ? 0400 : 0600); |
| |
| #ifdef O_CLOEXEC |
| // First try with O_CLOEXEC flag, if that fails, fall back to normal flags |
| EINTR_LOOP(hand, ::shm_open(shmName.constData(), oflag | O_CLOEXEC, omode)); |
| if (hand == -1) |
| EINTR_LOOP(hand, ::shm_open(shmName.constData(), oflag, omode)); |
| #else |
| EINTR_LOOP(hand, ::shm_open(shmName.constData(), oflag, omode)); |
| #endif |
| if (hand == -1) { |
| const int errorNumber = errno; |
| const QLatin1String function("QSharedMemory::attach (shm_open)"); |
| switch (errorNumber) { |
| case ENAMETOOLONG: |
| case EINVAL: |
| errorString = QSharedMemory::tr("%1: bad name").arg(function); |
| error = QSharedMemory::KeyError; |
| break; |
| default: |
| setErrorString(function); |
| } |
| hand = -1; |
| return false; |
| } |
| |
| // grab the size |
| QT_STATBUF st; |
| if (QT_FSTAT(hand, &st) == -1) { |
| setErrorString(QLatin1String("QSharedMemory::attach (fstat)")); |
| cleanHandle(); |
| return false; |
| } |
| size = st.st_size; |
| |
| // grab the memory |
| const int mprot = (mode == QSharedMemory::ReadOnly ? PROT_READ : PROT_READ | PROT_WRITE); |
| memory = QT_MMAP(0, size, mprot, MAP_SHARED, hand, 0); |
| if (memory == MAP_FAILED || !memory) { |
| setErrorString(QLatin1String("QSharedMemory::attach (mmap)")); |
| cleanHandle(); |
| memory = 0; |
| size = 0; |
| return false; |
| } |
| |
| #ifdef F_ADD_SEALS |
| // Make sure the shared memory region will not shrink |
| // otherwise someone could cause SIGBUS on us. |
| // (see http://lwn.net/Articles/594919/) |
| fcntl(hand, F_ADD_SEALS, F_SEAL_SHRINK); |
| #endif |
| |
| return true; |
| } |
| |
| bool QSharedMemoryPrivate::detach() |
| { |
| // detach from the memory segment |
| if (::munmap(memory, size) == -1) { |
| setErrorString(QLatin1String("QSharedMemory::detach (munmap)")); |
| return false; |
| } |
| memory = 0; |
| size = 0; |
| |
| #ifdef Q_OS_QNX |
| // On QNX the st_nlink field of struct stat contains the number of |
| // active shm_open() connections to the shared memory file, so we |
| // can use it to automatically clean up the file once the last |
| // user has detached from it. |
| |
| // get the number of current attachments |
| int shm_nattch = 0; |
| QT_STATBUF st; |
| if (QT_FSTAT(hand, &st) == 0) { |
| // subtract 2 from linkcount: one for our own open and one for the dir entry |
| shm_nattch = st.st_nlink - 2; |
| } |
| |
| cleanHandle(); |
| |
| // if there are no attachments then unlink the shared memory |
| if (shm_nattch == 0) { |
| const QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key)); |
| if (::shm_unlink(shmName.constData()) == -1 && errno != ENOENT) |
| setErrorString(QLatin1String("QSharedMemory::detach (shm_unlink)")); |
| } |
| #else |
| // On non-QNX systems (tested Linux and Haiku), the st_nlink field is always 1, |
| // so we'll simply leak the shared memory files. |
| cleanHandle(); |
| #endif |
| |
| return true; |
| } |
| |
| QT_END_NAMESPACE |
| |
| #endif // QT_NO_SHAREDMEMORY |
| |
| #endif // QT_POSIX_IPC |