IPC: move makePlatformSafeKey to qtipccommon.cpp

This removes the second portion of the #if mess of shared code between
QSharedMemory and QSystemSemaphore for SystemV.

Change-Id: Id8d5e3999fe94b03acc1fffd171c073c2873206e
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/corelib/CMakeLists.txt

@@ -110,6 +110,7 @@ qt_internal_add_module(Core
         global/qxptype_traits.h
         ipc/qsharedmemory.cpp ipc/qsharedmemory.h ipc/qsharedmemory_p.h
         ipc/qsystemsemaphore.cpp ipc/qsystemsemaphore.h ipc/qsystemsemaphore_p.h
+        ipc/qtipccommon.cpp ipc/qtipccommon_p.h
         io/qabstractfileengine.cpp io/qabstractfileengine_p.h
         io/qbuffer.cpp io/qbuffer.h
         io/qdataurl.cpp io/qdataurl_p.h

src/corelib/ipc/qsharedmemory.cpp

@@ -3,81 +3,19 @@
 
 #include "qsharedmemory.h"
 #include "qsharedmemory_p.h"
+
+#include "qtipccommon_p.h"
 #include "qsystemsemaphore.h"
-#include <qdir.h>
-#include <qcryptographichash.h>
+
 #include <qdebug.h>
 #ifdef Q_OS_WIN
 #  include <qt_windows.h>
 #endif
 
-#if defined(Q_OS_DARWIN)
-#  include "qcore_mac_p.h"
-#  if !defined(SHM_NAME_MAX)
-     // Based on PSEMNAMLEN in XNU's posix_sem.c, which would
-     // indicate the max length is 31, _excluding_ the zero
-     // terminator. But in practice (possibly due to an off-
-     // by-one bug in the kernel) the usable bytes are only 30.
-#    define SHM_NAME_MAX 30
-#  endif
-#endif
-
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
 
-#if QT_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
-/*!
-    \internal
-
-    Generate a string from the key which can be any unicode string into
-    the subset that the win/unix kernel allows.
-
-    On Unix this will be a file name
-  */
-QString
-QSharedMemoryPrivate::makePlatformSafeKey(const QString &key,
-                                          const QString &prefix)
-{
-    if (key.isEmpty())
-        return QString();
-
-    QByteArray hex = QCryptographicHash::hash(key.toUtf8(), QCryptographicHash::Sha1).toHex();
-
-#if defined(Q_OS_DARWIN) && defined(QT_POSIX_IPC)
-    if (qt_apple_isSandboxed()) {
-        // Sandboxed applications on Apple platforms require the shared memory name
-        // to be in the form <application group identifier>/<custom identifier>.
-        // Since we don't know which application group identifier the user wants
-        // to apply, we instead document that requirement, and use the key directly.
-        return key;
-    } else {
-        // The shared memory name limit on Apple platforms is very low (30 characters),
-        // so we can't use the logic below of combining the prefix, key, and a hash,
-        // to ensure a unique and valid name. Instead we use the first part of the
-        // hash, which should still long enough to avoid collisions in practice.
-        return u'/' + hex.left(SHM_NAME_MAX - 1);
-    }
-#endif
-
-    QString result = prefix;
-    for (QChar ch : key) {
-        if ((ch >= u'a' && ch <= u'z') ||
-           (ch >= u'A' && ch <= u'Z'))
-           result += ch;
-    }
-    result.append(QLatin1StringView(hex));
-
-#ifdef Q_OS_WIN
-    return result;
-#elif defined(QT_POSIX_IPC)
-    return u'/' + result;
-#else
-    return QDir::tempPath() + u'/' + result;
-#endif
-}
-#endif // QT_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
-
 #if QT_CONFIG(sharedmemory)
 
 /*!
@@ -306,14 +244,16 @@ QSharedMemory::~QSharedMemory()
 void QSharedMemory::setKey(const QString &key)
 {
     Q_D(QSharedMemory);
-    if (key == d->key && d->makePlatformSafeKey(key) == d->nativeKey)
+    QString newNativeKey =
+            QtIpcCommon::legacyPlatformSafeKey(key, QtIpcCommon::IpcType::SharedMemory);
+    if (key == d->key && newNativeKey == d->nativeKey)
         return;
 
     if (isAttached())
         detach();
     d->cleanHandle();
     d->key = key;
-    d->nativeKey = d->makePlatformSafeKey(key);
+    d->nativeKey = newNativeKey;
 }
 
 /*!

src/corelib/ipc/qsharedmemory_p.h

@@ -19,22 +19,7 @@
 
 #include <QtCore/qstring.h>
 
-#if !QT_CONFIG(sharedmemory)
-#    if QT_CONFIG(systemsemaphore)
-
-QT_BEGIN_NAMESPACE
-
-namespace QSharedMemoryPrivate
-{
-    QString makePlatformSafeKey(const QString &key,
-            const QString &prefix = QStringLiteral("qipc_sharedmemory_"));
-}
-
-QT_END_NAMESPACE
-
-#    endif
-#else
-
+#if QT_CONFIG(sharedmemory)
 #include "qsystemsemaphore.h"
 #include "private/qobject_p.h"
 
@@ -92,8 +77,6 @@ public:
     bool lockedByMe = false;
 #endif
 
-    static QString makePlatformSafeKey(const QString &key,
-            const QString &prefix = QStringLiteral("qipc_sharedmemory_"));
 #ifdef Q_OS_WIN
     Qt::HANDLE handle();
 #elif defined(QT_POSIX_IPC)

src/corelib/ipc/qsharedmemory_posix.cpp

@@ -7,7 +7,7 @@
 
 #include "qsharedmemory.h"
 #include "qsharedmemory_p.h"
-#include "qsystemsemaphore.h"
+#include "qtipccommon_p.h"
 #include <qfile.h>
 
 #include <errno.h>
@@ -26,11 +26,12 @@
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtIpcCommon;
 
 int QSharedMemoryPrivate::handle()
 {
     // don't allow making handles on empty keys
-    const QString safeKey = makePlatformSafeKey(key);
+    const QString safeKey = legacyPlatformSafeKey(key, QtIpcCommon::IpcType::SharedMemory);
     if (safeKey.isEmpty()) {
         errorString = QSharedMemory::tr("%1: key is empty").arg("QSharedMemory::handle"_L1);
         error = QSharedMemory::KeyError;
@@ -53,7 +54,7 @@ bool QSharedMemoryPrivate::create(qsizetype size)
     if (!handle())
         return false;
 
-    const QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key));
+    const QByteArray shmName = QFile::encodeName(legacyPlatformSafeKey(key, IpcType::SharedMemory));
 
     int fd;
 #ifdef O_CLOEXEC
@@ -94,7 +95,7 @@ bool QSharedMemoryPrivate::create(qsizetype size)
 
 bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
 {
-    const QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key));
+    const QByteArray shmName = QFile::encodeName(legacyPlatformSafeKey(key, IpcType::SharedMemory));
 
     const int oflag = (mode == QSharedMemory::ReadOnly ? O_RDONLY : O_RDWR);
     const mode_t omode = (mode == QSharedMemory::ReadOnly ? 0400 : 0600);
@@ -180,7 +181,7 @@ bool QSharedMemoryPrivate::detach()
 
     // if there are no attachments then unlink the shared memory
     if (shm_nattch == 0) {
-        const QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key));
+        const QByteArray shmName = QFile::encodeName(legacyPlatformSafeKey(key, IpcType::SharedMemory));
         if (::shm_unlink(shmName.constData()) == -1 && errno != ENOENT)
             setErrorString("QSharedMemory::detach (shm_unlink)"_L1);
     }

src/corelib/ipc/qsystemsemaphore_p.h

@@ -21,7 +21,6 @@
 
 #include "qcoreapplication.h"
 #include "qtipccommon_p.h"
-#include "qsharedmemory_p.h"
 
 #include <sys/types.h>
 #ifdef QT_POSIX_IPC
@@ -37,7 +36,7 @@ public:
 
     QString makeKeyFileName()
     {
-        return QSharedMemoryPrivate::makePlatformSafeKey(key, QLatin1StringView("qipc_systemsem_"));
+        return QtIpcCommon::legacyPlatformSafeKey(key, QtIpcCommon::IpcType::SystemSemaphore);
     }
 
     inline void setError(QSystemSemaphore::SystemSemaphoreError e, const QString &message)

src/corelib/ipc/qtipccommon.cpp

@@ -0,0 +1,89 @@
+// Copyright (C) 2022 Intel Corporation.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "qtipccommon_p.h"
+
+#include <qcryptographichash.h>
+#include <qdir.h>
+
+#if defined(Q_OS_DARWIN)
+#  include "private/qcore_mac_p.h"
+#  if !defined(SHM_NAME_MAX)
+     // Based on PSEMNAMLEN in XNU's posix_sem.c, which would
+     // indicate the max length is 31, _excluding_ the zero
+     // terminator. But in practice (possibly due to an off-
+     // by-one bug in the kernel) the usable bytes are only 30.
+#    define SHM_NAME_MAX 30
+#  endif
+#endif
+
+#if QT_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
+
+QT_BEGIN_NAMESPACE
+
+using namespace Qt::StringLiterals;
+
+/*!
+    \internal
+
+    Legacy: this exists for compatibility with QSharedMemory and
+    QSystemSemaphore between 4.4 and 6.6.
+
+    Generate a string from the key which can be any unicode string into
+    the subset that the win/unix kernel allows.
+
+    On Unix this will be a file name
+*/
+QString QtIpcCommon::legacyPlatformSafeKey(const QString &key, QtIpcCommon::IpcType ipcType)
+{
+    if (key.isEmpty())
+        return QString();
+
+    QByteArray hex = QCryptographicHash::hash(key.toUtf8(), QCryptographicHash::Sha1).toHex();
+
+#if defined(Q_OS_DARWIN) && defined(QT_POSIX_IPC)
+    if (qt_apple_isSandboxed()) {
+        // Sandboxed applications on Apple platforms require the shared memory name
+        // to be in the form <application group identifier>/<custom identifier>.
+        // Since we don't know which application group identifier the user wants
+        // to apply, we instead document that requirement, and use the key directly.
+        return key;
+    } else {
+        // The shared memory name limit on Apple platforms is very low (30 characters),
+        // so we can't use the logic below of combining the prefix, key, and a hash,
+        // to ensure a unique and valid name. Instead we use the first part of the
+        // hash, which should still long enough to avoid collisions in practice.
+        return u'/' + hex.left(SHM_NAME_MAX - 1);
+    }
+#endif
+
+    QString result;
+    result.reserve(1 + 18 + key.size() + 40);
+    switch (ipcType) {
+    case IpcType::SharedMemory:
+        result += "qipc_sharedmemory_"_L1;
+        break;
+    case IpcType::SystemSemaphore:
+        result += "qipc_systemsem_"_L1;
+        break;
+    }
+
+    for (QChar ch : key) {
+        if ((ch >= u'a' && ch <= u'z') ||
+           (ch >= u'A' && ch <= u'Z'))
+           result += ch;
+    }
+    result.append(QLatin1StringView(hex));
+
+#ifdef Q_OS_WIN
+    return result;
+#elif defined(QT_POSIX_IPC)
+    return u'/' + result;
+#else
+    return QDir::tempPath() + u'/' + result;
+#endif
+}
+
+QT_END_NAMESPACE
+
+#endif // QT_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)

src/corelib/ipc/qtipccommon_p.h

@@ -27,6 +27,13 @@
 QT_BEGIN_NAMESPACE
 
 namespace QtIpcCommon {
+enum class IpcType {
+    SharedMemory,
+    SystemSemaphore
+};
+
+Q_AUTOTEST_EXPORT QString legacyPlatformSafeKey(const QString &key, IpcType ipcType);
+
 #ifdef Q_OS_UNIX
 // Convenience function to create the file if needed
 inline int createUnixKeyFile(const QByteArray &fileName)

tests/auto/corelib/ipc/qsharedmemory/tst_qsharedmemory.cpp

@@ -135,7 +135,7 @@ void tst_QSharedMemory::cleanup()
 }
 
 #ifndef Q_OS_WIN
-#include <private/qsharedmemory_p.h>
+#include <private/qtipccommon_p.h>
 #include <sys/types.h>
 #ifndef QT_POSIX_IPC
 #include <sys/ipc.h>
@@ -157,7 +157,7 @@ int tst_QSharedMemory::remove(const QString &key)
     if (key.isEmpty())
         return -1;
 
-    QString fileName = QSharedMemoryPrivate::makePlatformSafeKey(key);
+    QString fileName = QtIpcCommon::legacyPlatformSafeKey(key, QtIpcCommon::IpcType::SharedMemory);
 
 #ifndef QT_POSIX_IPC
     // ftok requires that an actual file exists somewhere