Properly lock cs_main in rest_block

src/rest.cpp

@@ -11,6 +11,7 @@
 #include "core/transaction.h"
 #include "version.h"
 #include "main.h"
+#include "sync.h"
 
 using namespace std;
 using namespace json_spirit;
@@ -80,13 +81,17 @@ static bool rest_block(AcceptedConnection *conn,
     if (!ParseHashStr(hashStr, hash))
         throw RESTERR(HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);
 
+    CBlock block;
+    CBlockIndex* pblockindex = NULL;
+    {
+        LOCK(cs_main);
         if (mapBlockIndex.count(hash) == 0)
             throw RESTERR(HTTP_NOT_FOUND, hashStr + " not found");
 
-    CBlock block;
-    CBlockIndex* pblockindex = mapBlockIndex[hash];
+        pblockindex = mapBlockIndex[hash];
         if (!ReadBlockFromDisk(block, pblockindex))
             throw RESTERR(HTTP_NOT_FOUND, hashStr + " not found");
+    }
 
     CDataStream ssBlock(SER_NETWORK, PROTOCOL_VERSION);
     ssBlock << block;