[commit: unix] master: Fix putenv; trac #7342 (76dad7a)

[Ian Lynagh]

Repository : ssh://darcs.haskell.org//srv/darcs/packages/unix

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/76dad7afeaef33576940b64a7b3be91d05434df5

>---------------------------------------------------------------

commit 76dad7afeaef33576940b64a7b3be91d05434df5
Author: Ian Lynagh <ian at well-typed.com>
Date:   Sat Dec 1 22:31:48 2012 +0000

    Fix putenv; trac #7342
    
    We were freeing the string, but the string becomes part of the
    environment.

>---------------------------------------------------------------

 System/Posix/Env.hsc |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/System/Posix/Env.hsc b/System/Posix/Env.hsc
index ecc6281..f7878b8 100644
--- a/System/Posix/Env.hsc
+++ b/System/Posix/Env.hsc
@@ -38,7 +38,7 @@ import Foreign.Ptr
 import Foreign.Storable
 import Control.Monad
 import Data.Maybe (fromMaybe)
-import System.Posix.Internals (withFilePath, peekFilePath)
+import System.Posix.Internals
 
 -- |'getEnv' looks up a variable in the environment.
 
@@ -124,8 +124,11 @@ unsetEnv name = putEnv (name ++ "=")
 -- and is equivalent to @setEnv(key,value,True{-overwrite-})@.
 
 putEnv :: String -> IO ()
-putEnv keyvalue = withFilePath keyvalue $ \s ->
-  throwErrnoIfMinus1_ "putenv" (c_putenv s)
+putEnv keyvalue = do s <- newFilePath keyvalue
+                     -- Do not free `s` after calling putenv.
+                     -- According to SUSv2, the string passed to putenv
+                     -- becomes part of the enviroment. #7342
+                     throwErrnoIfMinus1_ "putenv" (c_putenv s)
 
 foreign import ccall unsafe "putenv"
    c_putenv :: CString -> IO CInt