From d0bdfc9c00fd921a79b24d8300cbf01a20f5a371 Mon Sep 17 00:00:00 2001
From: Jason Lokerson <cmercenary@gmail.com>
Date: Thu, 26 May 2016 17:17:59 -0700
Subject: [PATCH] Add a lock for `m_ContextIDs` and `m_ContextPtrs`

These members are often accessed in an unsynchronized context, synchronize them by adding a spin lock to ensure we do not wind up with memory smashers when using Autonet in highly concurrent settings.
---
 src/autonet/AutoNetServerImpl.cpp | 2 ++
 src/autonet/AutoNetServerImpl.hpp | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/autonet/AutoNetServerImpl.cpp b/src/autonet/AutoNetServerImpl.cpp
index 270090f97..4c77206cb 100644
--- a/src/autonet/AutoNetServerImpl.cpp
+++ b/src/autonet/AutoNetServerImpl.cpp
@@ -322,6 +322,7 @@ void AutoNetServerImpl::HandleUnsubscribe(websocketpp::connection_hdl hdl) {
 int AutoNetServerImpl::ResolveContextID(CoreContext* ctxt) {
   static int counter = 0;
 
+  std::lock_guard<autowiring::spin_lock> lk(m_lock);
   if(m_ContextIDs.find(ctxt) == m_ContextIDs.end()){
     m_ContextIDs[ctxt] = counter;
     m_ContextPtrs[counter] = ctxt;
@@ -333,6 +334,7 @@ int AutoNetServerImpl::ResolveContextID(CoreContext* ctxt) {
 }
 
 CoreContext* AutoNetServerImpl::ResolveContextID(int id) {
+  std::lock_guard<autowiring::spin_lock> lk(m_lock);
   return m_ContextPtrs.at(id);
 }
 
diff --git a/src/autonet/AutoNetServerImpl.hpp b/src/autonet/AutoNetServerImpl.hpp
index d214e695f..83faeda75 100644
--- a/src/autonet/AutoNetServerImpl.hpp
+++ b/src/autonet/AutoNetServerImpl.hpp
@@ -135,7 +135,8 @@ class AutoNetServerImpl:
   // Set of all subscribers
   std::set<AutoNetTransportHandler::connection_hdl, std::owner_less<AutoNetTransportHandler::connection_hdl>> m_Subscribers;
 
-  // one-to-one map of contexts to integers
+  // one-to-one map of contexts to integers, and a lock because we use this in an unsynchronized setting
+  autowiring::spin_lock m_lock;
   std::map<CoreContext*, int> m_ContextIDs;
   std::map<int, CoreContext*> m_ContextPtrs;