From a0379db01dce6b4371ead2ce82e4221e1ae8c334 Mon Sep 17 00:00:00 2001
From: Paolo Capriotti <p.capriotti@gmail.com>
Date: Wed, 4 Apr 2012 15:33:53 +0100
Subject: [PATCH] Add workaround for systems without clearenv.
---
System/Posix/Env.hsc | 11 ++++++++++-
configure.ac | 2 +-
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/System/Posix/Env.hsc b/System/Posix/Env.hsc
index 51e8891..be4711b 100644
--- a/System/Posix/Env.hsc
+++ b/System/Posix/Env.hsc
@@ -36,7 +36,7 @@ import Foreign.C.String
import Foreign.Marshal.Array
import Foreign.Ptr
import Foreign.Storable
-import Control.Monad (liftM, forM_, void)
+import Control.Monad
import Data.Maybe (fromMaybe)
#if __GLASGOW_HASKELL__ > 700
import System.Posix.Internals (withFilePath, peekFilePath)
@@ -83,6 +83,7 @@ getEnvironmentPrim = do
mapM peekFilePath arr
getCEnviron :: IO (Ptr CString)
+
#if darwin_HOST_OS
-- You should not access _environ directly on Darwin in a bundle/shared library.
-- See #2458 and http://developer.apple.com/library/mac/#documentation/Darwin/Reference/ManPages/man7/environ.7.html
@@ -170,7 +171,15 @@ setEnv key value False = do
-- |The 'clearEnv' function clears the environment of all name-value pairs.
clearEnv :: IO ()
+#if HAVE_CLEARENV
clearEnv = void c_clearenv
foreign import ccall unsafe "clearenv"
c_clearenv :: IO Int
+#else
+-- Fallback to 'environ[0] = NULL'.
+clearEnv = do
+ c_environ <- getCEnviron
+ unless (c_environ == nullPtr) $
+ poke c_environ nullPtr
+#endif
diff --git a/configure.ac b/configure.ac
index 775af6c..ebf708d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -28,7 +28,7 @@ AC_CHECK_HEADERS([termios.h time.h unistd.h utime.h])
AC_CHECK_FUNCS([getgrgid_r getgrnam_r getpwnam_r getpwuid_r getpwnam getpwuid])
AC_CHECK_FUNCS([getpwent getgrent])
-AC_CHECK_FUNCS([lchown setenv sysconf unsetenv])
+AC_CHECK_FUNCS([lchown setenv sysconf unsetenv clearenv])
AC_CHECK_FUNCS([nanosleep])
AC_CHECK_FUNCS([ptsname])
AC_CHECK_FUNCS([setitimer])
--
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