From ec314c951dbc17836f44b9fc2a1462940c338c27 Mon Sep 17 00:00:00 2001
From: Paul Sokolovsky <pfalcon@users.sourceforge.net>
Date: Sat, 14 Nov 2015 17:12:04 +0200
Subject: [PATCH] unix/modos: getenv(): Handle non-existing envvar correctly.

---
 unix/modos.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/unix/modos.c b/unix/modos.c
index 94f9a5723d..b4af796123 100644
--- a/unix/modos.c
+++ b/unix/modos.c
@@ -137,6 +137,9 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_os_system_obj, mod_os_system);
 
 STATIC mp_obj_t mod_os_getenv(mp_obj_t var_in) {
     const char *s = getenv(mp_obj_str_get_str(var_in));
+    if (s == NULL) {
+        return mp_const_none;
+    }
     return mp_obj_new_str(s, strlen(s), false);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_os_getenv_obj, mod_os_getenv);