search parent pids for tty and fall back to DISPLAY variable.

1 files changed, 27 insertions, 14 deletions

diff --git a/whosocket.hs b/whosocket.hs
index 5968b152..6955830a 100644
--- a/whosocket.hs
+++ b/whosocket.hs
@@ -74,18 +74,31 @@ scanProc uid inode = do
 
     fmap (fmap (first (read :: String -> CPid))) $ searchPids pids
 
-ttyOrDisplay pid ttydev | take 8 ttydev == "/dev/tty" = return (drop 5 ttydev)
 ttyOrDisplay pid ttydev = do
-    env <- handleIO_ (return "") . readFile $ "/proc/"++show pid++"/environ"
-    let vs = unzero $ groupBy (\_ c->c/='\0') env
-        unzero []     = []
-        unzero (v:vs) = v:map tail vs
-        keyvalue xs = (key,value) 
-          where
-            (key,ys) = break (=='=') xs
-            value = case ys of { [] -> [];  (_:ys') -> ys' }
-        display = listToMaybe . filter ((=="DISPLAY").fst) . map keyvalue $ vs
-    putStrLn $ "display = " ++ show display
-    case display of
-        Just (_,disp) -> return disp
-        _             -> return ttydev
+    ptty <- searchParentsForTTY (show pid) ttydev
+    case ptty of
+        Just tty -> return tty
+        Nothing  -> do
+            env <- handleIO_ (return "") . readFile $ "/proc/"++show pid++"/environ"
+            let vs = unzero $ groupBy (\_ c->c/='\0') env
+                unzero []     = []
+                unzero (v:vs) = v:map tail vs
+                keyvalue xs = (key,value) 
+                  where
+                    (key,ys) = break (=='=') xs
+                    value = case ys of { [] -> [];  (_:ys') -> ys' }
+                display = listToMaybe . filter ((=="DISPLAY").fst) . map keyvalue $ vs
+            putStrLn $ "display = " ++ show display
+            case display of
+                Just (_,disp) -> return disp
+                _             -> return ttydev
+
+searchParentsForTTY pid  ttydev | take 8 ttydev == "/dev/tty" = return . Just $ drop 5 ttydev
+searchParentsForTTY "1"  ttydev | otherwise                   = return Nothing
+searchParentsForTTY pid ttydev = do
+    stat <- handleIO_ (return "") . readFile $ "/proc/"++pid++"/stat"
+    case words stat ?? 3 of
+        Nothing   -> return Nothing
+        Just ppid -> do
+          tty <- handleIO_ (return "") $ readSymbolicLink $ "/proc/"++ppid++"/fd/0"
+          searchParentsForTTY ppid tty