IPC/QSharedMemory: call QSystemSemaphore::setKey only once (not 3)

And we particularly want to avoid calling with Create twice. Change-Id: I12a088d1ae424825abd3fffd171d6ab1fb87221f Reviewed-by: Mårten Nordheim <[email protected]>
BAYEKHELIX · Jan 22, 2023 · b330f21 · b330f21
1 parent 2c28656
commit b330f21
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Showing 2 changed files with 15 additions and 17 deletions.
diff --git a/src/corelib/ipc/qsharedmemory.cpp b/src/corelib/ipc/qsharedmemory.cpp
@@ -227,13 +227,12 @@ void QSharedMemory::setNativeKey(const QNativeIpcKey &key)
     d->nativeKey = key;
 }
 
-bool QSharedMemoryPrivate::initKey()
+bool QSharedMemoryPrivate::initKey(SemaphoreAccessMode mode)
 {
     if (!cleanHandle())
         return false;
 #if QT_CONFIG(systemsemaphore)
-    systemSemaphore.setNativeKey(QNativeIpcKey(), 1);
-    systemSemaphore.setNativeKey(semaphoreNativeKey(), 1);
+    systemSemaphore.setNativeKey(semaphoreNativeKey(), 1, mode);
     if (systemSemaphore.error() != QSystemSemaphore::NoError) {
         QString function = "QSharedMemoryPrivate::initKey"_L1;
         errorString = QSharedMemory::tr("%1: unable to set key on lock").arg(function);
@@ -260,6 +259,8 @@ bool QSharedMemoryPrivate::initKey()
         }
         return false;
     }
+#else
+    Q_UNUSED(mode);
 #endif
     errorString = QString();
     error = QSharedMemory::NoError;
@@ -335,23 +336,17 @@ QNativeIpcKey QSharedMemory::nativeIpcKey() const
 bool QSharedMemory::create(qsizetype size, AccessMode mode)
 {
     Q_D(QSharedMemory);
+    QLatin1StringView function = "QSharedMemory::create"_L1;
 
-    if (!d->initKey())
-        return false;
-
-#if QT_CONFIG(systemsemaphore)
-#ifndef Q_OS_WIN
-    // Take ownership and force set initialValue because the semaphore
-    // might have already existed from a previous crash.
-    d->systemSemaphore.setKey(d->semaphoreNativeKey(), 1, QSystemSemaphore::Create);
-#endif
-#endif
-
-    QString function = "QSharedMemory::create"_L1;
 #if QT_CONFIG(systemsemaphore)
+    if (!d->initKey(QSystemSemaphore::Create))
+        return false;
     QSharedMemoryLocker lock(this);
     if (!d->nativeKey.isEmpty() && !d->tryLocker(&lock, function))
         return false;
+#else
+    if (!d->initKey({}))
+        return false;
 #endif
 
     if (size <= 0) {
@@ -410,7 +405,7 @@ bool QSharedMemory::attach(AccessMode mode)
 {
     Q_D(QSharedMemory);
 
-    if (isAttached() || !d->initKey())
+    if (isAttached() || !d->initKey({}))
         return false;
 #if QT_CONFIG(systemsemaphore)
     QSharedMemoryLocker lock(this);

diff --git a/src/corelib/ipc/qsharedmemory_p.h b/src/corelib/ipc/qsharedmemory_p.h
@@ -127,8 +127,11 @@ class Q_AUTOTEST_EXPORT QSharedMemoryPrivate : public QObjectPrivate
     QNativeIpcKey nativeKey;
     QString errorString;
 #if QT_CONFIG(systemsemaphore)
+    using SemaphoreAccessMode = QSystemSemaphore::AccessMode;
     QSystemSemaphore systemSemaphore{ QNativeIpcKey() };
     bool lockedByMe = false;
+#else
+    enum SemaphoreAccessMode {};
 #endif
     QSharedMemory::SharedMemoryError error = QSharedMemory::NoError;
 
@@ -141,7 +144,7 @@ class Q_AUTOTEST_EXPORT QSharedMemoryPrivate : public QObjectPrivate
 #endif
     DefaultBackend backend;
 
-    bool initKey();
+    bool initKey(SemaphoreAccessMode mode);
 
     bool handle()
     {