[commit: unix] ghc-7.6: Fix a memory corruption issue in putEnv (fixes #7342) (b95a003)

[Ian Lynagh]

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

On branch  : ghc-7.6

http://hackage.haskell.org/trac/ghc/changeset/b95a003b20436863ef2f5fc01e6cd77f5bef94a0

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

commit b95a003b20436863ef2f5fc01e6cd77f5bef94a0
Author: Simon Hengel <sol at typeful.net>
Date:   Thu Oct 18 00:27:42 2012 +0200

    Fix a memory corruption issue in putEnv (fixes #7342)

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

 System/Posix/Env.hsc |   17 ++++++++++++++++-
 1 files changed, 16 insertions(+), 1 deletions(-)

diff --git a/System/Posix/Env.hsc b/System/Posix/Env.hsc
index be4711b..c30a20e 100644
--- a/System/Posix/Env.hsc
+++ b/System/Posix/Env.hsc
@@ -38,6 +38,10 @@ import Foreign.Ptr
 import Foreign.Storable
 import Control.Monad
 import Data.Maybe (fromMaybe)
+#ifdef __GLASGOW_HASKELL__
+import GHC.IO.Encoding (getFileSystemEncoding)
+import qualified GHC.Foreign as GHC
+#endif
 #if __GLASGOW_HASKELL__ > 700
 import System.Posix.Internals (withFilePath, peekFilePath)
 #elif __GLASGOW_HASKELL__ > 611
@@ -53,6 +57,13 @@ peekFilePath :: CString -> IO FilePath
 peekFilePath = peekCString
 #endif
 
+newFilePath :: String -> IO CString
+#ifdef __GLASGOW_HASKELL__
+newFilePath s = getFileSystemEncoding >>= (`GHC.newCString` s)
+#else
+newFilePath = newCString
+#endif
+
 -- |'getEnv' looks up a variable in the environment.
 
 getEnv :: String -> IO (Maybe String)
@@ -137,7 +148,11 @@ unsetEnv name = putEnv (name ++ "=")
 -- and is equivalent to @setEnv(key,value,True{-overwrite-})@.
 
 putEnv :: String -> IO ()
-putEnv keyvalue = withFilePath keyvalue $ \s ->
+putEnv keyvalue = newFilePath keyvalue >>= \s ->
+  -- IMPORTANT: Do not free `s` after calling putenv!
+  --
+  -- According to SUSv2, the string passed to putenv becomes part of the
+  -- enviroment.
   throwErrnoIfMinus1_ "putenv" (c_putenv s)
 
 foreign import ccall unsafe "putenv"