Avoid a crash when run without a controlling tty, which may happen in some container environments.

1 files changed, 12 insertions, 1 deletions

diff --git a/ControlWindow.hs b/ControlWindow.hs
index bd79d0f..29c81c9 100644
--- a/ControlWindow.hs
+++ b/ControlWindow.hs
@@ -98,9 +98,20 @@ type Response = String
 type PromptChan = TChan Prompt
 type ResponseChan = TChan Response
 
+-- | Get a name for the debug-me user. When possible this will be the
+-- actual username, but failing that, anything reasonable will do,
+-- since it's only ever displayed to the person they are communicating
+-- with.
+getUserName :: IO String
+getUserName = do
+	loginname <- try getLoginName :: IO (Either SomeException String)
+	case loginname of
+		Right n -> return n
+		Left _ -> return "user"
+
 collectOutput :: TMChan ControlOutput -> PromptChan -> ResponseChan -> IO ()
 collectOutput ochan promptchan responsechan = do
-	myusername <- fromString <$> getLoginName
+	myusername <- fromString <$> getUserName
 	loop myusername
   where
 	loop myusername = do