cmd_prompt: handle NULL output

* if the user aborted we receive a NULL pointer; don't attempt to
  dereference it, and treat this case as a failure.

Matches the behaviour of cmd_colon and cmd_select

1 files changed, 6 insertions, 2 deletions

diff --git a/src/actions.c b/src/actions.c
index e61497e..fa5af52 100644
--- a/src/actions.c
+++ b/src/actions.c
@@ -5826,9 +5826,13 @@ cmd_prompt (int interactive UNUSED, struct cmdarg **args)
           output = get_input (ARG_STRING(0), hist_PROMPT, trivial_completions);
         }
     }
+
+  if (output == NULL)
+    return cmdret_new (RET_FAILURE, NULL); /* User aborted */
+
   ret = cmdret_new (RET_SUCCESS, "%s", output);
-  if (output)
-    free (output);
+  free (output);
+
   return ret;
 }