6 files changed, 32 insertions, 7 deletions
diff --git a/src/corelib/io/qfilesystemengine_unix.cpp b/src/corelib/io/qfilesystemengine_unix.cpp
index 77d154c6b4..e590e259e7 100644
--- a/src/corelib/io/qfilesystemengine_unix.cpp
+++ b/src/corelib/io/qfilesystemengine_unix.cpp
@@ -108,6 +108,16 @@ struct statx { mode_t stx_mode; };
 
 QT_BEGIN_NAMESPACE
 
+enum {
+#ifdef Q_OS_ANDROID
+    // On Android, the link(2) system call has been observed to always fail
+    // with EACCES, regardless of whether there are permission problems or not.
+    SupportsHardlinking = false
+#else
+    SupportsHardlinking = true
+#endif
+};
+
 #define emptyFileEntryWarning() emptyFileEntryWarning_(QT_MESSAGELOG_FILE, QT_MESSAGELOG_LINE, QT_MESSAGELOG_FUNC)
 static void emptyFileEntryWarning_(const char *file, int line, const char *function)
 {
@@ -1287,7 +1297,7 @@ bool QFileSystemEngine::renameFile(const QFileSystemEntry &source, const QFileSy
     }
 #endif
 
-    if (::link(srcPath, tgtPath) == 0) {
+    if (SupportsHardlinking && ::link(srcPath, tgtPath) == 0) {
         if (::unlink(srcPath) == 0)
             return true;
 
@@ -1301,6 +1311,11 @@ bool QFileSystemEngine::renameFile(const QFileSystemEntry &source, const QFileSy
 
         error = QSystemError(savedErrno, QSystemError::StandardLibraryError);
         return false;
+    } else if (!SupportsHardlinking) {
+        // man 2 link on Linux has:
+        // EPERM  The filesystem containing oldpath and newpath does not
+        //        support the creation of hard links.
+        errno = EPERM;
     }
 
     switch (errno) {
diff --git a/src/corelib/io/qiodevice.cpp b/src/corelib/io/qiodevice.cpp
index 0a3e83206b..7d46898911 100644
--- a/src/corelib/io/qiodevice.cpp
+++ b/src/corelib/io/qiodevice.cpp
@@ -1879,7 +1879,7 @@ QByteArray QIODevice::peek(qint64 maxSize)
 }
 
 /*!
-    \since 5.11
+    \since 5.10
 
     Skips up to \a maxSize bytes from the device. Returns the number of bytes
     actually skipped, or -1 on error.
diff --git a/src/corelib/io/qloggingregistry.cpp b/src/corelib/io/qloggingregistry.cpp
index 0e7eaeea76..1bf61017f6 100644
--- a/src/corelib/io/qloggingregistry.cpp
+++ b/src/corelib/io/qloggingregistry.cpp
@@ -255,6 +255,7 @@ void QLoggingSettingsParser::parseNextLine(QStringRef line)
 QLoggingRegistry::QLoggingRegistry()
     : categoryFilter(defaultCategoryFilter)
 {
+    initalizeRules(); // Init on first use
 }
 
 static bool qtLoggingDebug()
@@ -283,7 +284,7 @@ static QVector<QLoggingRule> loadRulesFromFile(const QString &filePath)
     Initializes the rules database by loading
     $QT_LOGGING_CONF, $QT_LOGGING_RULES, and .config/QtProject/qtlogging.ini.
  */
-void QLoggingRegistry::init()
+void QLoggingRegistry::initalizeRules()
 {
     QVector<QLoggingRule> er, qr, cr;
     // get rules from environment
diff --git a/src/corelib/io/qloggingregistry_p.h b/src/corelib/io/qloggingregistry_p.h
index a68b993cca..a3857d3588 100644
--- a/src/corelib/io/qloggingregistry_p.h
+++ b/src/corelib/io/qloggingregistry_p.h
@@ -113,7 +113,7 @@ class Q_AUTOTEST_EXPORT QLoggingRegistry
 public:
     QLoggingRegistry();
 
-    void init();
+    void initalizeRules();
 
     void registerCategory(QLoggingCategory *category, QtMsgType enableForLevel);
     void unregisterCategory(QLoggingCategory *category);
diff --git a/src/corelib/io/qsettings.cpp b/src/corelib/io/qsettings.cpp
index d0cbc82c56..bbc66120b5 100644
--- a/src/corelib/io/qsettings.cpp
+++ b/src/corelib/io/qsettings.cpp
@@ -1451,7 +1451,7 @@ void QConfFileSettingsPrivate::syncConfFile(QConfFile *confFile)
             Files that we can't read (because of permissions or
             because they don't exist) are treated as empty files.
         */
-        if (file.isReadable() && fileInfo.size() != 0) {
+        if (file.isReadable() && file.size() != 0) {
             bool ok = false;
 #ifdef Q_OS_MAC
             if (format == QSettings::NativeFormat) {
diff --git a/src/corelib/io/qstandardpaths_win.cpp b/src/corelib/io/qstandardpaths_win.cpp
index 41fd31df8b..eeb02419c3 100644
--- a/src/corelib/io/qstandardpaths_win.cpp
+++ b/src/corelib/io/qstandardpaths_win.cpp
@@ -201,6 +201,10 @@ QString QStandardPaths::writableLocation(StandardLocation type)
     return result;
 }
 
+#ifndef QT_BOOTSTRAPPED
+extern QString qAppFileName();
+#endif
+
 QStringList QStandardPaths::standardLocations(StandardLocation type)
 {
     QStringList dirs;
@@ -217,8 +221,13 @@ QStringList QStandardPaths::standardLocations(StandardLocation type)
             dirs.append(programData);
         }
 #ifndef QT_BOOTSTRAPPED
-        dirs.append(QCoreApplication::applicationDirPath());
-        const QString dataDir = QCoreApplication::applicationDirPath() + QLatin1String("/data");
+        // Note: QCoreApplication::applicationDirPath(), while static, requires
+        // an application instance. But we might need to resolve the standard
+        // locations earlier than that, so we fall back to qAppFileName().
+        QString applicationDirPath = qApp ? QCoreApplication::applicationDirPath()
+            : QFileInfo(qAppFileName()).path();
+        dirs.append(applicationDirPath);
+        const QString dataDir = applicationDirPath + QLatin1String("/data");
         dirs.append(dataDir);
 
         if (!isGenericConfigLocation(type)) {