From edf8ef3b4d6eae065f0e4bcece2a15a7f5a25ecc Mon Sep 17 00:00:00 2001
From: Ivailo Monev <xakepa10@gmail.com>
Date: Sun, 16 Jan 2022 20:07:42 +0200
Subject: [PATCH] open file exclusively for read/write in
 QSettingsPrivate::write()

Signed-off-by: Ivailo Monev <xakepa10@gmail.com>
---
 src/core/io/qsettings.cpp | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/core/io/qsettings.cpp b/src/core/io/qsettings.cpp
index 69f210346..559bfe7ac 100644
--- a/src/core/io/qsettings.cpp
+++ b/src/core/io/qsettings.cpp
@@ -286,21 +286,23 @@ void QSettingsPrivate::write()
     }
 
     QMutexLocker locker(qSettingsMutex());
-    QFile file(filename);
-    if (Q_UNLIKELY(!file.open(QFile::ReadWrite))) {
+    QFile writefile(filename);
+    if (Q_UNLIKELY(!writefile.open(QFile::WriteOnly))) {
         status = QSettings::AccessError;
         qWarning("QSettingsPrivate::write: failed to open %s", filename.toLocal8Bit().constData());
         return;
     }
 
     QSettings::SettingsMap mergemap;
-    readFunc(file, mergemap);
-    file.seek(0);
+    QFile readfile(filename);
+    if (readfile.open(QFile::ReadOnly)) {
+        readFunc(readfile, mergemap);
+    }
     foreach(const QString &key, map.keys()) {
         mergemap.insert(key, map.value(key));
     }
 
-    if (Q_UNLIKELY(!writeFunc(file, mergemap))) {
+    if (Q_UNLIKELY(!writeFunc(writefile, mergemap))) {
         status = QSettings::FormatError;
         qWarning("QSettingsPrivate::write: could not write %s", filename.toLocal8Bit().constData());
         return;