core: moan when we think an update is needed to get latest hard fork info

src/cryptonote_core/blockchain.cpp

@@ -3074,3 +3074,8 @@ void Blockchain::set_user_options(uint64_t maxthreads, uint64_t blocks_per_sync,
     m_db_blocks_per_sync = blocks_per_sync;
     m_max_prepare_blocks_threads = maxthreads;
 }
+
+HardFork::State Blockchain::get_hard_fork_state() const
+{
+    return m_hardfork.get_state();
+}

src/cryptonote_core/blockchain.h

@@ -159,6 +159,8 @@ namespace cryptonote
 
     void set_show_time_stats(bool stats) { m_show_time_stats = stats; }
     
+    HardFork::State get_hard_fork_state() const;
+
     BlockchainDB& get_db()
     {
       return *m_db;

src/cryptonote_core/cryptonote_core.cpp

@@ -830,11 +830,37 @@ namespace cryptonote
 #else
     m_store_blockchain_interval.do_call(boost::bind(&blockchain_storage::store_blockchain, &m_blockchain_storage));
 #endif
+    m_fork_moaner.do_call(boost::bind(&core::check_fork_time, this));
     m_miner.on_idle();
     m_mempool.on_idle();
     return true;
   }
   //-----------------------------------------------------------------------------------------------
+  bool core::check_fork_time()
+  {
+#if BLOCKCHAIN_DB == DB_LMDB
+    HardFork::State state = m_blockchain_storage.get_hard_fork_state();
+    switch (state) {
+      case HardFork::LikelyForked:
+        LOG_PRINT_L0(ENDL
+          << "**********************************************************************" << ENDL
+          << "Last scheduled hard fork is too far in the past." << ENDL
+          << "We are most likely forked from the network. Daemon update needed now." << ENDL
+          << "**********************************************************************" << ENDL);
+        break;
+      case HardFork::UpdateNeeded:
+        LOG_PRINT_L0(ENDL
+          << "**********************************************************************" << ENDL
+          << "Last scheduled hard fork time shows a daemon update is needed now." << ENDL
+          << "**********************************************************************" << ENDL);
+        break;
+      default:
+        break;
+    }
+#endif
+    return true;
+  }
+  //-----------------------------------------------------------------------------------------------
   void core::set_target_blockchain_height(uint64_t target_blockchain_height)
   {
     m_target_blockchain_height = target_blockchain_height;

src/cryptonote_core/cryptonote_core.h

@@ -167,6 +167,7 @@ namespace cryptonote
      bool on_update_blocktemplate_interval();
      bool check_tx_inputs_keyimages_diff(const transaction& tx);
      void graceful_exit();
+     bool check_fork_time();
      static std::atomic<bool> m_fast_exit;
      bool m_test_drop_download = true;
 	 uint64_t m_test_drop_download_height = 0;
@@ -185,6 +186,7 @@ namespace cryptonote
      std::string m_config_folder;
      cryptonote_protocol_stub m_protocol_stub;
      epee::math_helper::once_a_time_seconds<60*60*12, false> m_store_blockchain_interval;
+     epee::math_helper::once_a_time_seconds<60*60*2, false> m_fork_moaner;
      friend class tx_validate_inputs;
      std::atomic<bool> m_starter_message_showed;