Implement support for Lua 5.1

Author: p0pr0ck5

build/lua.m4

@@ -6,7 +6,7 @@ AC_DEFUN([CHECK_LUA],
 [dnl
 
 # Possible names for the lua library/package (pkg-config)
-LUA_POSSIBLE_LIB_NAMES="lua lua53 lua5.3 lua52 lua5.2"
+LUA_POSSIBLE_LIB_NAMES="lua lua53 lua5.3 lua52 lua5.2 lua51 lua5.1"
 
 # Possible extensions for the library
 LUA_POSSIBLE_EXTENSIONS="so so0 la sl dll dylib so.0.0.0"
@@ -88,10 +88,6 @@ if test -z "${LUA_CFLAGS}"; then
        LUA_FOUND=-1
     fi
 else
-    if test "${lua_5_1}" = 1 && test "x${LUA_MANDATORY}" == "xyes" ; then
-       AC_MSG_ERROR([LUA was explicitly referenced but LUA v5.1 was found and it is not currently supported on libModSecurity. LUA_VERSION: ${LUA_VERSION}])
-       LUA_FOUND=-1
-    fi
     if test -z "${LUA_MANDATORY}" || test "x${LUA_MANDATORY}" == "xno"; then
         LUA_FOUND=1
         AC_MSG_NOTICE([using LUA ${LUA_LDADD}])
@@ -113,15 +109,6 @@ else
     fi
 fi
 
-if test "${lua_5_1}" = 1 ; then
-   AC_MSG_NOTICE([LUA 5.1 was found and it is not currently supported on libModSecurity. LUA_VERSION: ${LUA_VERSION}. LUA build disabled.])
-   LUA_FOUND=2
-   LUA_CFLAGS=
-   LUA_DISPLAY=
-   LUA_LDADD=
-   LUA_LDFLAGS=
-fi
-
 AC_SUBST(LUA_FOUND)
 
 ]) # AC_DEFUN [CHECK_LUA]
@@ -179,6 +166,9 @@ AC_DEFUN([CHECK_FOR_LUA_AT], [
     elif test -e "${path}/include/lua5.2/lua.h"; then
         lua_inc_path="${path}/include/lua5.2"
 	LUA_VERSION=502
+    elif test -e "${path}/include/lua5.1/lua.h"; then
+        lua_inc_path="${path}/include/lua5.1"
+	LUA_VERSION=501
     fi
 
     if test -n "${lua_lib_path}"; then

src/engine/lua.cc

@@ -82,7 +82,7 @@ bool Lua::load(std::string script, std::string *err) {
         return false;
     }
 
-#ifdef WITH_LUA_5_2
+#if defined (WITH_LUA_5_2) || defined (WITH_LUA_5_1)
     if (lua_dump(L, Lua::blob_keeper, reinterpret_cast<void *>(&m_blob))) {
 #else
     if (lua_dump(L, Lua::blob_keeper, reinterpret_cast<void *>(&m_blob), 0)) {
@@ -138,8 +138,12 @@ int Lua::run(Transaction *t) {
     luaL_setfuncs(L, mscLuaLib, 0);
     lua_setglobal(L, "m");
 
+#ifdef WITH_LUA_5_1
+    int rc = lua_load(L, Lua::blob_reader, &m_blob, m_scriptName.c_str());
+#else
     int rc = lua_load(L, Lua::blob_reader, &m_blob, m_scriptName.c_str(),
         NULL);
+#endif
     if (rc != LUA_OK) {
         std::string e;
         e.assign("Failed to execute lua script: " + m_scriptName + ". ");
@@ -150,9 +154,11 @@ int Lua::run(Transaction *t) {
             case LUA_ERRMEM:
                 e.assign("Memory error. ");
                 break;
+#ifndef WITH_LUA_5_1
             case LUA_ERRGCMM:
                 e.assign("Garbage Collector error. ");
                 break;
+#endif
         }
         e.append(lua_tostring(L, -1));
 #ifndef NO_LOGS
@@ -402,7 +408,11 @@ std::string Lua::applyTransformations(lua_State *L, Transaction *t,
 
     if (lua_istable(L, idx)) {
         const char *name = NULL;
+#ifdef WITH_LUA_5_1
+        int i, n = lua_objlen(L, idx);
+#else
         int i, n = lua_rawlen(L, idx);
+#endif
 
         for (i = 1; i <= n; i++) {
             lua_rawgeti(L, idx, i);

src/engine/lua.h

@@ -101,4 +101,29 @@ static const struct luaL_Reg mscLuaLib[] = {
 }  // namespace engine
 }  // namespace modsecurity
 
+#ifdef WITH_LUA
+#if defined LUA_VERSION_NUM && LUA_VERSION_NUM < 502
+/*
+** Adapted from Lua 5.2.0
+*/
+#define LUA_OK 0
+
+static void luaL_setfuncs(lua_State *L, const luaL_Reg *l, int nup) {
+    luaL_checkstack(L, nup + 1, "too many upvalues");
+
+    for (; l->name != NULL; l++) {  /* fill the table with given functions */
+        int i;
+        lua_pushstring(L, l->name);
+        for (i = 0; i < nup; i++)  /* copy upvalues to the top */
+          lua_pushvalue(L, -(nup + 1));
+        lua_pushcclosure(L, l->func, nup);  /* closure with those upvalues */
+        lua_settable(L, -(nup + 3));
+    }
+
+    lua_pop(L, nup);  /* remove upvalues */
+}
+#endif
+#endif
+
+
 #endif  // SRC_ENGINE_LUA_H_