[U-Boot] [PATCH 4/6] cmd: mtdparts: fix mtdparts variable presence confusion in mtdparts_init

[Ladislav Michl <ladis@linux-mips.org>]

A private buffer is used to read mtdparts variable from non-relocated
environment. A pointer to that buffer is returned unconditionally,
confusing later test for variable presence in the environment.
Fix it by returning NULL when getenv_f fails.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
--
diff --git a/cmd/mtdparts.c b/cmd/mtdparts.c
index 44b2c3a..3a88a10 100644
--- a/cmd/mtdparts.c
+++ b/cmd/mtdparts.c
@@ -1720,11 +1720,13 @@ int mtdparts_init(void)
 	 * before the env is relocated, then we need to use our own stack
 	 * buffer.  gd->env_buf will be too small.
 	 */
-	if (gd->flags & GD_FLG_ENV_READY) {
+	if (gd->flags & GD_FLG_ENV_READY)
 		parts = getenv("mtdparts");
-	} else {
-		parts = tmp_parts;
-		getenv_f("mtdparts", tmp_parts, MTDPARTS_MAXLEN);
+	else {
+		if (getenv_f("mtdparts", tmp_parts, MTDPARTS_MAXLEN) != -1)
+			parts = tmp_parts;
+		else
+			parts = NULL;
 	}
 	current_partition = getenv("partition");
 
-- 
2.1.4