1 files changed, 3 insertions, 1 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 181357c1c..d4b60f081 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -8144,10 +8144,12 @@ calcsize(union node *n)
 }
 
 static char *
-nodeckstrdup(char *s)
+nodeckstrdup(const char *s)
 {
         char *rtn = funcstring;
 
+        if (!s)
+                return NULL;
         strcpy(funcstring, s);
         funcstring += strlen(s) + 1;
         return rtn;