Implement review suggestions

ui/module.go

@@ -29,6 +29,14 @@ func prep() error {
 }
 
 func start() error {
+	// Create a dummy directory to which processes change their working directory
+	// to. Currently this includes the App and the Notifier. The aim is protect
+	// all other directories and increase compatibility should any process want
+	// to read or write something to the current working directory. This can also
+	// be useful in the future to dump data to for debugging. The permission used
+	// may seem dangerous, but proper permission on the parent directory provide
+	// (some) protection.
+	// Processes must _never_ read from this directory.
 	err := dataroot.Root().ChildDir("exec", 0777).Ensure()
 	if err != nil {
 		log.Warningf("ui: failed to create safe exec dir: %s", err)