Use USER and HOME environment when set, and only fall back to getpwent, which doesn't work with LDAP or NIS.

Utility/UserInfo.hs

@@ -0,0 +1,32 @@
+{- user info
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Utility.UserInfo (
+	myHomeDir,
+	myUserName
+) where
+
+import Control.Applicative
+import System.Posix.User
+import System.Posix.Env
+
+{- Current user's home directory.
+ -
+ - getpwent will fail on LDAP or NIS, so use HOME if set. -}
+myHomeDir :: IO FilePath
+myHomeDir = myVal ["HOME"] homeDirectory
+
+{- Current user's user name. -}
+myUserName :: IO String
+myUserName = myVal ["USER", "LOGNAME"] userName
+
+myVal :: [String] -> (UserEntry -> String) -> IO String
+myVal envvars extract = maybe (extract <$> getpwent) return =<< check envvars
+	where
+		check [] = return Nothing
+		check (v:vs) = maybe (check vs) (return . Just) =<< getEnv v
+		getpwent = getUserEntryForID =<< getEffectiveUserID