IPC: move createUnixKeyFile to a common, private header

So we don't have to mess around with #ifs to support the build.

Drive-by replace with unlink() some calls to QFile::remove(), which
create a QFSFileEngine, to call QFSFileEngine::remove, which calls
QFileSystemEngine::removeFile. Since we've just created the file with
qt_safe_open(), we may as well use the low-level Unix function to remove
too.

Change-Id: Id8d5e3999fe94b03acc1fffd171c06c7efc0b0f0
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/corelib/ipc/qsharedmemory_android.cpp

@@ -20,19 +20,6 @@ key_t QSharedMemoryPrivate::handle()
     return 0;
 }
 
-#endif // QT_CONFIG(sharedmemory)
-
-#if QT_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
-int QSharedMemoryPrivate::createUnixKeyFile(const QString &fileName)
-{
-    Q_UNUSED(fileName);
-    Q_UNIMPLEMENTED();
-    return 0;
-}
-#endif // QT_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
-
-#if QT_CONFIG(sharedmemory)
-
 bool QSharedMemoryPrivate::cleanHandle()
 {
     Q_UNIMPLEMENTED();

src/corelib/ipc/qsharedmemory_p.h

@@ -26,7 +26,6 @@ QT_BEGIN_NAMESPACE
 
 namespace QSharedMemoryPrivate
 {
-    int createUnixKeyFile(const QString &fileName);
     QString makePlatformSafeKey(const QString &key,
             const QString &prefix = QStringLiteral("qipc_sharedmemory_"));
 }
@@ -93,7 +92,6 @@ public:
     bool lockedByMe = false;
 #endif
 
-    static int createUnixKeyFile(const QString &fileName);
     static QString makePlatformSafeKey(const QString &key,
             const QString &prefix = QStringLiteral("qipc_sharedmemory_"));
 #ifdef Q_OS_WIN

src/corelib/ipc/qsharedmemory_systemv.cpp

@@ -1,11 +1,11 @@
 // Copyright (C) 2016 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
-#include "qplatformdefs.h"
-
 #include "qsharedmemory.h"
 #include "qsharedmemory_p.h"
-#include "qsystemsemaphore.h"
+
+#include "qtipccommon_p.h"
+
 #include <qdir.h>
 #include <qdebug.h>
 
@@ -28,6 +28,7 @@
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
+using namespace QtIpcCommon;
 
 /*!
     \internal
@@ -63,35 +64,6 @@ key_t QSharedMemoryPrivate::handle()
     return unix_key;
 }
 
-#endif // QT_CONFIG(sharedmemory)
-
-#if QT_CONFIG(sharedmemory) || QT_CONFIG(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 QT_PREPEND_NAMESPACE(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_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
-
-#if QT_CONFIG(sharedmemory)
-
 bool QSharedMemoryPrivate::cleanHandle()
 {
     unix_key = 0;
@@ -102,7 +74,8 @@ bool QSharedMemoryPrivate::create(qsizetype size)
 {
     // build file if needed
     bool createdFile = false;
-    int built = createUnixKeyFile(nativeKey);
+    QByteArray nativeKeyFile = QFile::encodeName(nativeKey);
+    int built = createUnixKeyFile(nativeKeyFile);
     if (built == -1) {
         errorString = QSharedMemory::tr("%1: unable to make key").arg("QSharedMemory::handle:"_L1);
         error = QSharedMemory::KeyError;
@@ -115,7 +88,7 @@ bool QSharedMemoryPrivate::create(qsizetype size)
     // get handle
     if (!handle()) {
         if (createdFile)
-            QFile::remove(nativeKey);
+            unlink(nativeKeyFile);
         return false;
     }
 
@@ -131,7 +104,7 @@ bool QSharedMemoryPrivate::create(qsizetype size)
             setErrorString(function);
         }
         if (createdFile && error != QSharedMemory::AlreadyExists)
-            QFile::remove(nativeKey);
+            unlink(nativeKeyFile);
         return false;
     }
 
@@ -212,7 +185,7 @@ bool QSharedMemoryPrivate::detach()
         }
 
         // remove file
-        if (!QFile::remove(nativeKey))
+        if (!unlink(QFile::encodeName(nativeKey)))
             return false;
     }
     return true;

src/corelib/ipc/qsystemsemaphore_p.h

@@ -20,7 +20,9 @@
 #if QT_CONFIG(systemsemaphore)
 
 #include "qcoreapplication.h"
+#include "qtipccommon_p.h"
 #include "qsharedmemory_p.h"
+
 #include <sys/types.h>
 #ifdef QT_POSIX_IPC
 #   include <semaphore.h>

src/corelib/ipc/qsystemsemaphore_systemv.cpp

@@ -63,7 +63,7 @@ key_t QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode mode)
         return unix_key;
 
     // Create the file needed for ftok
-    int built = QSharedMemoryPrivate::createUnixKeyFile(fileName);
+    int built = QtIpcCommon::createUnixKeyFile(QFile::encodeName(fileName));
     if (-1 == built) {
         errorString = QSystemSemaphore::tr("%1: unable to make key")
                       .arg("QSystemSemaphore::handle:"_L1);

src/corelib/ipc/qtipccommon_p.h

@@ -0,0 +1,53 @@
+// 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
+
+#ifndef QTIPCCOMMON_P_H
+#define QTIPCCOMMON_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qglobal_p.h>
+
+#if QT_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
+
+#if defined(Q_OS_UNIX)
+#  include <qfile.h>
+#  include <private/qcore_unix_p.h>
+#endif
+
+QT_BEGIN_NAMESPACE
+
+namespace QtIpcCommon {
+#ifdef Q_OS_UNIX
+// Convenience function to create the file if needed
+inline int createUnixKeyFile(const QByteArray &fileName)
+{
+    int fd = qt_safe_open(fileName.constData(), O_EXCL | O_CREAT | O_RDWR, 0640);
+    if (fd < 0) {
+        if (errno == EEXIST)
+            return 0;
+        return -1;
+    } else {
+        close(fd);
+    }
+    return 1;
+
+}
+#endif // Q_OS_UNIX
+} // namespace QtIpcCommon
+
+QT_END_NAMESPACE
+
+#endif // QT_CONFIG(sharedmemory) || QT_CONFIG(systemsemaphore)
+
+
+#endif // QTIPCCOMMON_P_H