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/****************************************************************************
**
** Copyright (C) 2012 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.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** 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.
**
** 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.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qplatformdefs.h"
#include "qsharedmemory.h"
#include "qsharedmemory_p.h"
#include <qdebug.h>
#include <qfile.h>
#ifndef QT_NO_SHAREDMEMORY
#include <sys/types.h>
#include <sys/ipc.h>
#ifndef QT_POSIX_IPC
#include <sys/shm.h>
#else
#include <sys/mman.h>
#include <sys/stat.h>
#endif
#include <fcntl.h>
#include <unistd.h>
#endif // QT_NO_SHAREDMEMORY
#include <errno.h>
#include "private/qcore_unix_p.h"
#ifndef QT_NO_SHAREDMEMORY
//#define QSHAREDMEMORY_DEBUG
QT_BEGIN_NAMESPACE
QSharedMemoryPrivate::QSharedMemoryPrivate()
: QObjectPrivate(), memory(0), size(0), error(QSharedMemory::NoError),
#ifndef QT_NO_SYSTEMSEMAPHORE
systemSemaphore(QString()), lockedByMe(false),
#endif
#ifndef QT_POSIX_IPC
unix_key(0)
#else
hand(0)
#endif
{
}
void QSharedMemoryPrivate::setErrorString(const QString &function)
{
// EINVAL is handled in functions so they can give better error strings
switch (errno) {
case EACCES:
case EPERM:
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 EAGAIN:
case EMFILE:
case ENFILE:
case ENOMEM:
case ENOSPC:
errorString = QSharedMemory::tr("%1: out of resources").arg(function);
error = QSharedMemory::OutOfResources;
break;
case EOVERFLOW:
errorString = QSharedMemory::tr("%1: invalid size").arg(function);
error = QSharedMemory::InvalidSize;
break;
default:
errorString = QSharedMemory::tr("%1: unknown error %2").arg(function).arg(errno);
error = QSharedMemory::UnknownError;
#ifdef QSHAREDMEMORY_DEBUG
qDebug() << errorString << "key" << key << "errno" << errno << EINVAL;
#endif
break;
}
}
/*!
\internal
If not already made create the handle used for accessing the shared memory.
*/
#ifndef QT_POSIX_IPC
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;
}
#else
int QSharedMemoryPrivate::handle()
{
// don't allow making handles on empty keys
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;
}
#endif // QT_POSIX_IPC
#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)
{
#ifndef QT_POSIX_IPC
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 {
qt_safe_close(fd);
}
return 1;
#else
Q_UNUSED(fileName);
// nothing to do
return -1;
#endif
}
#endif // QT_NO_SHAREDMEMORY && QT_NO_SYSTEMSEMAPHORE
#ifndef QT_NO_SHAREDMEMORY
void QSharedMemoryPrivate::cleanHandle()
{
#ifndef QT_POSIX_IPC
unix_key = 0;
#else
qt_safe_close(hand);
hand = 0;
#endif
}
bool QSharedMemoryPrivate::create(int size)
{
#ifndef QT_POSIX_IPC
// build file if needed
int built = createUnixKeyFile(nativeKey);
if (built == -1) {
errorString = QSharedMemory::tr("%1: unable to make key").arg(QLatin1String("QSharedMemory::create"));
error = QSharedMemory::KeyError;
return false;
}
bool createdFile = built == 1;
// get handle
if (!handle()) {
if (createdFile)
QFile::remove(nativeKey);
return false;
}
// create
if (-1 == shmget(unix_key, size, 0600 | IPC_CREAT | IPC_EXCL)) {
QString function = QLatin1String("QSharedMemory::create");
switch (errno) {
case EINVAL:
errorString = QSharedMemory::tr("%1: system-imposed size restrictions").arg(function);
error = QSharedMemory::InvalidSize;
break;
default:
setErrorString(function);
}
if (createdFile && error != QSharedMemory::AlreadyExists)
QFile::remove(nativeKey);
return false;
}
#else
if (!handle())
return false;
QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key));
int fd;
EINTR_LOOP(fd, shm_open(shmName.constData(), O_RDWR | O_CREAT | O_EXCL, 0666));
if (fd == -1) {
QString function = QLatin1String("QSharedMemory::create");
switch (errno) {
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; ignore errors
int ret;
EINTR_LOOP(ret, ftruncate(fd, size));
if (ret == -1) {
setErrorString(QLatin1String("QSharedMemory::create (ftruncate)"));
qt_safe_close(fd);
return false;
}
qt_safe_close(fd);
#endif // QT_POSIX_IPC
return true;
}
bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
{
#ifndef QT_POSIX_IPC
// 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;
}
#else
QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key));
int oflag = (mode == QSharedMemory::ReadOnly ? O_RDONLY : O_RDWR);
mode_t omode = (mode == QSharedMemory::ReadOnly ? 0444 : 0660);
EINTR_LOOP(hand, shm_open(shmName.constData(), oflag, omode));
if (hand == -1) {
QString function = QLatin1String("QSharedMemory::attach (shm_open)");
switch (errno) {
case ENAMETOOLONG:
case EINVAL:
errorString = QSharedMemory::tr("%1: bad name").arg(function);
error = QSharedMemory::KeyError;
break;
default:
setErrorString(function);
}
hand = 0;
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
int mprot = (mode == QSharedMemory::ReadOnly ? PROT_READ : PROT_READ | PROT_WRITE);
memory = 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;
}
#endif // QT_POSIX_IPC
return true;
}
bool QSharedMemoryPrivate::detach()
{
#ifndef QT_POSIX_IPC
// 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, 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::detach"));
switch (errno) {
case EINVAL:
return true;
default:
return false;
}
}
// remove file
if (!QFile::remove(nativeKey))
return false;
}
#else
// detach from the memory segment
if (munmap(memory, size) == -1) {
setErrorString(QLatin1String("QSharedMemory::detach (munmap)"));
return false;
}
memory = 0;
size = 0;
// 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) {
QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key));
if (shm_unlink(shmName.constData()) == -1 && errno != ENOENT)
setErrorString(QLatin1String("QSharedMemory::detach (shm_unlink)"));
}
#endif // QT_POSIX_IPC
return true;
}
QT_END_NAMESPACE
#endif // QT_NO_SHAREDMEMORY
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