Revert to r32212.

My recent changes are causing problems when I try to integrate them into
the ncat-sa-take2 branch.

ncat/ncat_core.c

@@ -204,10 +204,6 @@ void options_init(void)
     o.proxy_auth = NULL;
     o.proxytype = NULL;
 
-#ifdef HAVE_LUA
-    o.lua_exec_state = NULL;
-#endif
-
 #ifdef HAVE_OPENSSL
     o.ssl = 0;
     o.sslcert = NULL;

ncat/ncat_core.h

@@ -126,10 +126,6 @@
 #include "util.h"
 #include "sockaddr_u.h"
 
-#ifdef HAVE_LUA
-#include "ncat_lua.h"
-#endif
-
 /* Maximum size of the srcaddrs array. In this case two because we can only have
    a IPV4 INADDR_ANY and a IPV6 in6addr_any at most or a user defined address */
 #define NUM_LISTEN_ADDRS 2
@@ -202,10 +198,6 @@ struct options {
     char *proxy_auth;
     char *proxytype;
 
-#ifdef HAVE_LUA
-    lua_State *lua_exec_state;
-#endif
-
     int ssl;
     char *sslcert;
     char *sslkey;

ncat/ncat_lua.c

@@ -124,7 +124,10 @@
 #include "ncat.h"
 #include "ncat_lua.h"
 
-static void report(lua_State *L, char *prefix)
+static lua_State *L;
+static int last_function_number;
+
+static void report(char *prefix)
 {
     const char *errormsg;
     errormsg = lua_tostring(L, -1);
@@ -148,41 +151,32 @@ static int traceback (lua_State *L)
     return 1;
 }
 
-lua_State *lua_setup(const char *filename)
+void lua_setup(void)
 {
-    lua_State *L;
-
-    ncat_assert(filename != NULL);
+    ncat_assert(o.cmdexec != NULL);
 
     L = luaL_newstate();
     luaL_openlibs(L);
 
-    if (luaL_loadfile(L, filename) != 0)
-        report(L, "Error loading the Lua script");
+    if (luaL_loadfile(L, o.cmdexec) != 0)
+        report("Error loading the Lua script");
 
-    return L;
+    /* install the traceback function */
+    last_function_number = lua_gettop(L);
+    lua_pushcfunction(L, traceback);
+    lua_insert(L, last_function_number);
 }
 
-void lua_run(lua_State *L)
+void lua_run(void)
 {
-    if (lua_call_traceback(L, 0, 0) != LUA_OK && !lua_isnil(L, -1)) {
-        report(L, "Error running the Lua script");
+    if (lua_pcall(L, 0, 0, last_function_number) != LUA_OK && !lua_isnil(L, -1)) {
+        /* handle the error; the code below is taken from lua.c, Lua source code */
+        lua_remove(L, last_function_number);
+        report("Error running the Lua script");
     } else {
         if (o.debug)
-            logdebug("Lua script returned successfully.\n");
+            logdebug("%s returned successfully.\n", o.cmdexec);
         lua_close(L);
         exit(EXIT_SUCCESS);
     }
 }
-
-
-/* Returns the value of a lua_pcall of the chunk on top of the stack, with an
-   error handler that prints a traceback. */
-int lua_call_traceback(lua_State *L, int nargs, int nresults)
-{
-    /* The chunk to run is on top of the stack. Put the traceback function
-       before it and run it. */
-    lua_pushcfunction(L, traceback);
-    lua_insert(L, -2);
-    return lua_pcall(L, nargs, nresults, -2);
-}

ncat/ncat_lua.h

@@ -124,8 +124,6 @@
 #ifndef _NCAT_LUA_H
 #define _NCAT_LUA_H
 
-#include "ncat.h"
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -138,8 +136,7 @@ extern "C" {
 }
 #endif
 
-lua_State *lua_setup(const char *filename);
-void lua_run(lua_State *L);
-int lua_call_traceback(lua_State *L, int nargs, int nresults);
+void lua_setup(void);
+void lua_run(void);
 
 #endif

ncat/ncat_main.c

@@ -535,8 +535,6 @@ int main(int argc, char *argv[])
                    forking in POSIX builds, Windows does not have the fork() system
                    call and thus requires this workaround. More info here:
                    http://seclists.org/nmap-dev/2013/q2/492 */
-                lua_State *L;
-
 #ifdef WIN32
                 if (o.debug)
                     logdebug("Enabling binary stdout for the Lua output.\n");
@@ -545,9 +543,9 @@ int main(int argc, char *argv[])
                     perror("Cannot set mode");
 #endif
                 ncat_assert(argc == 3);
-                L = lua_setup(argv[2]);
-                ncat_assert(L != NULL);
-                lua_run(L);
+                o.cmdexec = argv[2];
+                lua_setup();
+                lua_run();
             }
 #endif
             break;
@@ -871,7 +869,7 @@ connection brokering should work.");
 
 #ifdef HAVE_LUA
     if (o.execmode == EXEC_LUA)
-        o.lua_exec_state = lua_setup(o.cmdexec);
+        lua_setup();
 #endif
 
     if (o.listen)

ncat/ncat_posix.c

@@ -234,7 +234,7 @@ void netexec(struct fdinfo *info, char *cmdexec)
             break;
 #ifdef HAVE_LUA
         case EXEC_LUA:
-            lua_run(o.lua_exec_state);
+            lua_run();
             break;
 #endif
         default: