From dab741f30fea8345d00039ac43e2dfa204a613a8 Mon Sep 17 00:00:00 2001
From: david <david@e0a8ed71-7df4-0310-8962-fdc924857419>
Date: Wed, 15 Jul 2009 02:54:03 +0000
Subject: [PATCH] Make nse_selectedbyname return false if the
 "NSE_SELECTED_BY_NAME" key is not in the registry. That function is called
 indirectly by nmap.verbosity, which may be called before
 _R["NSE_SELECTED_BY_NAME"] has been given a value. I was getting this error
 with any script scan:

NSE: failed to initialize the script engine:
attempt to call a nil value
stack traceback:
        [C]: in function 'verbosity'
        ./nse_main.lua:136: in function 'print_verbose'
        ./nse_main.lua:680: in main chunk
        [C]: ?

QUITTING!
---
 nse_main.cc | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/nse_main.cc b/nse_main.cc
index 2a5ae05fe..26be4393f 100644
--- a/nse_main.cc
+++ b/nse_main.cc
@@ -533,7 +533,12 @@ void nse_base (lua_State *L)
 void nse_selectedbyname (lua_State *L)
 {
   lua_getfield(L, LUA_REGISTRYINDEX, NSE_SELECTED_BY_NAME);
-  lua_call(L, 0, 1); /* returns boolean, whether script was selected by name */
+  if (lua_isnil(L, -1)) {
+    lua_pushboolean(L, 0);
+    lua_replace(L, -2);
+  } else {
+    lua_call(L, 0, 1); /* returns boolean, whether script was selected by name */
+  }
 }
 
 static lua_State *L_NSE = NULL;