From 714fa064dcc57b7c7e3cdeb1f62c9f36cfea6e51 Mon Sep 17 00:00:00 2001
From: Simon Marlow <marlowsd@gmail.com>
Date: Mon, 29 Mar 2010 11:27:13 +0000
Subject: make getAllGroupEntries work when called again; fixes #3816

---
 System/Posix/User.hsc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/System/Posix/User.hsc b/System/Posix/User.hsc
index 2427de0..e1c0f95 100644
--- a/System/Posix/User.hsc
+++ b/System/Posix/User.hsc
@@ -222,7 +222,7 @@ getGroupEntryForName = error "System.Posix.User.getGroupEntryForName: not suppor
 getAllGroupEntries :: IO [GroupEntry]
 #ifdef HAVE_GETGRENT
 getAllGroupEntries =
-    withMVar lock $ \_ -> worker []
+    withMVar lock $ \_ -> bracket_ c_setgrent c_endgrent $ worker []
     where worker accum =
               do resetErrno
                  ppw <- throwErrnoIfNullAndError "getAllGroupEntries" $ 
@@ -234,6 +234,10 @@ getAllGroupEntries =
 
 foreign import ccall unsafe "getgrent"
   c_getgrent :: IO (Ptr CGroup)
+foreign import ccall unsafe "setgrent"
+  c_setgrent :: IO ()
+foreign import ccall unsafe "endgrent"
+  c_endgrent :: IO ()
 #else
 getAllGroupEntries = error "System.Posix.User.getAllGroupEntries: not supported"
 #endif
-- 
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