[PATCH] ntdll: Only call putenv() if we are going to call exec()

[Martin Storsjo]

If we aren't going to exec (if pre_exec() returns zero), we will
continue using the envp pointer we got from the caller. However,
the putenv() call does update the environment, and this can in
some cases overwrite the array that the old (stale, potentially
dangling) envp pointer points to.

Signed-off-by: Martin Storsjo 
---
 dlls/ntdll/unix/loader.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/dlls/ntdll/unix/loader.c b/dlls/ntdll/unix/loader.c
index d621d4ef8e..47d9ebe684 100644
--- a/dlls/ntdll/unix/loader.c
+++ b/dlls/ntdll/unix/loader.c
@@ -1685,12 +1685,13 @@ void __wine_main( int argc, char *argv[], char *envp[] )

if (!getenv( "WINELOADERNOEXEC" ))  /* first time around */
     {
-        static char noexec[] = "WINELOADERNOEXEC=1";
-
-        putenv( noexec );
         check_command_line( argc, argv );
         if (pre_exec())
         {
+            static char noexec[] = "WINELOADERNOEXEC=1";
+
+            putenv( noexec );
+
             char **new_argv = malloc( (argc + 2) * sizeof(*argv) );
             memcpy( new_argv + 1, argv, (argc + 1) * sizeof(*argv) );
             loader_exec( argv0, new_argv, client_cpu );