3 files changed, 32 insertions, 3 deletions
diff --git a/src/corelib/io/qfilesystemengine_p.h b/src/corelib/io/qfilesystemengine_p.h
index de18c997df..196ed8df69 100644
--- a/src/corelib/io/qfilesystemengine_p.h
+++ b/src/corelib/io/qfilesystemengine_p.h
@@ -92,6 +92,8 @@ public:
                              QFileSystemMetaData::MetaDataFlags what);
 #if defined(Q_OS_UNIX)
     static bool fillMetaData(int fd, QFileSystemMetaData &data); // what = PosixStatFlags
+    static bool setPermissions(int fd, QFile::Permissions permissions, QSystemError &error,
+                               QFileSystemMetaData *data = nullptr);
 #endif
 #if defined(Q_OS_WIN)
 
diff --git a/src/corelib/io/qfilesystemengine_unix.cpp b/src/corelib/io/qfilesystemengine_unix.cpp
index 4ffa6b8972..b26ab2c903 100644
--- a/src/corelib/io/qfilesystemengine_unix.cpp
+++ b/src/corelib/io/qfilesystemengine_unix.cpp
@@ -659,8 +659,7 @@ bool QFileSystemEngine::removeFile(const QFileSystemEntry &entry, QSystemError &
 
 }
 
-//static
-bool QFileSystemEngine::setPermissions(const QFileSystemEntry &entry, QFile::Permissions permissions, QSystemError &error, QFileSystemMetaData *data)
+static mode_t toMode_t(QFile::Permissions permissions)
 {
     mode_t mode = 0;
     if (permissions & (QFile::ReadOwner | QFile::ReadUser))
@@ -681,6 +680,13 @@ bool QFileSystemEngine::setPermissions(const QFileSystemEntry &entry, QFile::Per
         mode |= S_IWOTH;
     if (permissions & QFile::ExeOther)
         mode |= S_IXOTH;
+    return mode;
+}
+
+//static
+bool QFileSystemEngine::setPermissions(const QFileSystemEntry &entry, QFile::Permissions permissions, QSystemError &error, QFileSystemMetaData *data)
+{
+    mode_t mode = toMode_t(permissions);
 
     bool success = ::chmod(entry.nativeFilePath().constData(), mode) == 0;
     if (success && data) {
@@ -693,6 +699,22 @@ bool QFileSystemEngine::setPermissions(const QFileSystemEntry &entry, QFile::Per
     return success;
 }
 
+//static
+bool QFileSystemEngine::setPermissions(int fd, QFile::Permissions permissions, QSystemError &error, QFileSystemMetaData *data)
+{
+    mode_t mode = toMode_t(permissions);
+
+    bool success = ::fchmod(fd, mode) == 0;
+    if (success && data) {
+        data->entryFlags &= ~QFileSystemMetaData::Permissions;
+        data->entryFlags |= QFileSystemMetaData::MetaDataFlag(uint(permissions));
+        data->knownFlagsMask |= QFileSystemMetaData::Permissions;
+    }
+    if (!success)
+        error = QSystemError(errno, QSystemError::StandardLibraryError);
+    return success;
+}
+
 QString QFileSystemEngine::homePath()
 {
     QString home = QFile::decodeName(qgetenv("HOME"));
diff --git a/src/corelib/io/qfsfileengine_unix.cpp b/src/corelib/io/qfsfileengine_unix.cpp
index e152b035e2..3f4f593d81 100644
--- a/src/corelib/io/qfsfileengine_unix.cpp
+++ b/src/corelib/io/qfsfileengine_unix.cpp
@@ -654,7 +654,12 @@ bool QFSFileEngine::setPermissions(uint perms)
 {
     Q_D(QFSFileEngine);
     QSystemError error;
-    if (!QFileSystemEngine::setPermissions(d->fileEntry, QFile::Permissions(perms), error, 0)) {
+    bool ok;
+    if (d->fd != -1)
+        ok = QFileSystemEngine::setPermissions(d->fd, QFile::Permissions(perms), error, 0);
+    else
+        ok = QFileSystemEngine::setPermissions(d->fileEntry, QFile::Permissions(perms), error, 0);
+    if (!ok) {
         setError(QFile::PermissionsError, error.toString());
         return false;
     }