MINOR: lua: file dedicated to unsafe functions

When Lua executes functions from its API, these can throws an error.
These function must be executed in a special environment which catch
these error, otherwise a critical error (like segfault) can raise.

This patch add a c file called "hlua_fcn.c" which collect all the
Lua/c function needing safe environment for its execution.

Makefile

@@ -610,7 +610,7 @@ OPTIONS_LDFLAGS += $(LUA_LD_FLAGS) -l$(LUA_LIB_NAME) -lm
 ifneq ($(USE_DL),)
 OPTIONS_LDFLAGS += -ldl
 endif
-OPTIONS_OBJS    += src/hlua.o
+OPTIONS_OBJS    += src/hlua.o src/hlua_fcn.o
 endif
 
 ifneq ($(USE_DEVICEATLAS),)

include/proto/hlua_fcn.h

@@ -0,0 +1,6 @@
+#ifndef _PROTO_HLUA_FCN_H
+#define _PROTO_HLUA_FCN_H
+
+int hlua_fcn_reg_core_fcn(lua_State *L);
+
+#endif /* _PROTO_HLUA_FCN_H */

src/hlua.c

@@ -24,6 +24,7 @@
 #include <proto/channel.h>
 #include <proto/hdr_idx.h>
 #include <proto/hlua.h>
+#include <proto/hlua_fcn.h>
 #include <proto/map.h>
 #include <proto/obj_type.h>
 #include <proto/pattern.h>
@@ -6632,6 +6633,7 @@ void hlua_init(void)
 	hlua_class_function(gL.T, "Warning", hlua_log_warning);
 	hlua_class_function(gL.T, "Alert", hlua_log_alert);
 	hlua_class_function(gL.T, "done", hlua_done);
+	hlua_fcn_reg_core_fcn(gL.T);
 
 	lua_setglobal(gL.T, "core");
 

src/hlua_fcn.c

@@ -0,0 +1,21 @@
+/* All the functions in this file runs with aLua stack, and can
+ * return with a longjmp. All of these function must be launched
+ * in an environment able to catch a longjmp, otherwise a
+ * critical error can be raised.
+ */
+#include <lauxlib.h>
+#include <lua.h>
+#include <lualib.h>
+
+static void hlua_array_add_fcn(lua_State *L, const char *name,
+                               int (*function)(lua_State *L))
+{
+	lua_pushstring(L, name);
+	lua_pushcclosure(L, function, 0);
+	lua_rawset(L, -3);
+}
+
+int hlua_fcn_reg_core_fcn(lua_State *L)
+{
+	return 0;
+}