effects/screenshot: Fix potentially leaking screenshot fds to child processes

dup() doesn't copy flags such as FD_CLOEXEC.

src/effects/screenshot/screenshotdbusinterface2.cpp

@@ -367,7 +367,7 @@ QVariantMap ScreenShotDBusInterface2::CaptureActiveWindow(const QVariantMap &opt
         return QVariantMap();
     }
 
-    const int fileDescriptor = dup(pipe.fileDescriptor());
+    const int fileDescriptor = fcntl(pipe.fileDescriptor(), F_DUPFD_CLOEXEC, 0);
     if (fileDescriptor == -1) {
         sendErrorReply(s_errorFileDescriptor, s_errorFileDescriptorMessage);
         return QVariantMap();
@@ -403,7 +403,7 @@ QVariantMap ScreenShotDBusInterface2::CaptureWindow(const QString &handle,
         return QVariantMap();
     }
 
-    const int fileDescriptor = dup(pipe.fileDescriptor());
+    const int fileDescriptor = fcntl(pipe.fileDescriptor(), F_DUPFD_CLOEXEC, 0);
     if (fileDescriptor == -1) {
         sendErrorReply(s_errorFileDescriptor, s_errorFileDescriptorMessage);
         return QVariantMap();
@@ -430,7 +430,7 @@ QVariantMap ScreenShotDBusInterface2::CaptureArea(int x, int y, int width, int h
         return QVariantMap();
     }
 
-    const int fileDescriptor = dup(pipe.fileDescriptor());
+    const int fileDescriptor = fcntl(pipe.fileDescriptor(), F_DUPFD_CLOEXEC, 0);
     if (fileDescriptor == -1) {
         sendErrorReply(s_errorFileDescriptor, s_errorFileDescriptorMessage);
         return QVariantMap();
@@ -457,7 +457,7 @@ QVariantMap ScreenShotDBusInterface2::CaptureScreen(const QString &name,
         return QVariantMap();
     }
 
-    const int fileDescriptor = dup(pipe.fileDescriptor());
+    const int fileDescriptor = fcntl(pipe.fileDescriptor(), F_DUPFD_CLOEXEC, 0);
     if (fileDescriptor == -1) {
         sendErrorReply(s_errorFileDescriptor, s_errorFileDescriptorMessage);
         return QVariantMap();
@@ -483,7 +483,7 @@ QVariantMap ScreenShotDBusInterface2::CaptureActiveScreen(const QVariantMap &opt
         return QVariantMap();
     }
 
-    const int fileDescriptor = dup(pipe.fileDescriptor());
+    const int fileDescriptor = fcntl(pipe.fileDescriptor(), F_DUPFD_CLOEXEC, 0);
     if (fileDescriptor == -1) {
         sendErrorReply(s_errorFileDescriptor, s_errorFileDescriptorMessage);
         return QVariantMap();
@@ -500,7 +500,7 @@ QVariantMap ScreenShotDBusInterface2::CaptureInteractive(uint kind,
                                                          const QVariantMap &options,
                                                          QDBusUnixFileDescriptor pipe)
 {
-    const int fileDescriptor = dup(pipe.fileDescriptor());
+    const int fileDescriptor = fcntl(pipe.fileDescriptor(), F_DUPFD_CLOEXEC, 0);
     if (fileDescriptor == -1) {
         sendErrorReply(s_errorFileDescriptor, s_errorFileDescriptorMessage);
         return QVariantMap();
@@ -555,7 +555,7 @@ QVariantMap ScreenShotDBusInterface2::CaptureWorkspace(const QVariantMap &option
         return QVariantMap();
     }
 
-    const int fileDescriptor = dup(pipe.fileDescriptor());
+    const int fileDescriptor = fcntl(pipe.fileDescriptor(), F_DUPFD_CLOEXEC, 0);
     if (fileDescriptor == -1) {
         sendErrorReply(s_errorFileDescriptor, s_errorFileDescriptorMessage);
         return QVariantMap();