From 32829819a9d93bcaa9dd3ab83bd5f399ad30a3dd Mon Sep 17 00:00:00 2001
From: Peter van Dijk <peter.van.dijk@powerdns.com>
Date: Mon, 3 Jun 2019 22:52:49 +0200
Subject: [PATCH] make LUA state reuse optional

---
 pdns/common_startup.cc |  1 +
 pdns/common_startup.hh |  1 +
 pdns/lua-record.cc     | 12 ++++++------
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/pdns/common_startup.cc b/pdns/common_startup.cc
index bd57fc542..1d1e51fea 100644
--- a/pdns/common_startup.cc
+++ b/pdns/common_startup.cc
@@ -511,6 +511,7 @@ void mainthread()
    g_8bitDNS = ::arg().mustDo("8bit-dns");
 #ifdef HAVE_LUA_RECORDS
    g_doLuaRecord = ::arg().mustDo("enable-lua-records");
+   g_LuaRecordSharedState = (::arg()["enable-lua-records"] == "shared");
    g_luaRecordExecLimit = ::arg().asNum("lua-records-exec-limit");
 #endif
 
diff --git a/pdns/common_startup.hh b/pdns/common_startup.hh
index 1e1290ed5..b57b4bcd5 100644
--- a/pdns/common_startup.hh
+++ b/pdns/common_startup.hh
@@ -57,6 +57,7 @@ extern bool g_anyToTcp;
 extern bool g_8bitDNS;
 #ifdef HAVE_LUA_RECORDS
 extern bool g_doLuaRecord;
+extern bool g_LuaRecordSharedState;
 #endif // HAVE_LUA_RECORDS
 
 #endif // COMMON_STARTUP_HH
diff --git a/pdns/lua-record.cc b/pdns/lua-record.cc
index 3d757415f..0e2b9102b 100644
--- a/pdns/lua-record.cc
+++ b/pdns/lua-record.cc
@@ -465,19 +465,19 @@ static vector<pair<int, ComboAddress> > convWIplist(std::unordered_map<int, wipl
   return ret;
 }
 
-thread_local unique_ptr<AuthLua4> alua;
+static thread_local unique_ptr<AuthLua4> s_LUA;
+bool g_LuaRecordSharedState;
 
 std::vector<shared_ptr<DNSRecordContent>> luaSynth(const std::string& code, const DNSName& query, const DNSName& zone, int zoneid, const DNSPacket& dnsp, uint16_t qtype)
 {
-  if(!alua) {
-    cerr<<"initializing AuthLua4"<<endl;
-
-    alua = make_unique<AuthLua4>();
+  if(!s_LUA ||                  // we don't have a Lua state yet
+     !g_LuaRecordSharedState) { // or we want a new one even if we had one
+    s_LUA = make_unique<AuthLua4>();
   }
 
   std::vector<shared_ptr<DNSRecordContent>> ret;
 
-  LuaContext& lua = *alua->getLua();
+  LuaContext& lua = *s_LUA->getLua();
   lua.writeVariable("qname", query);
   lua.writeVariable("who", dnsp.getRemote());
   lua.writeVariable("dh", (dnsheader*)&dnsp.d);
-- 
2.40.0