Merge pull request #8924

ffbf9f4 blockchain_and_pool: move to crytonote_core and enforce its usage (jeffro256)
d6f86e5 Avoid nullptr dereference when constructing Blockchain and tx_memory_pool (lukas)

12 files changed, 115 insertions, 98 deletions

diff --git a/src/blockchain_utilities/blockchain_ancestry.cpp b/src/blockchain_utilities/blockchain_ancestry.cpp
index 66dd7813b..36c17357a 100644
--- a/src/blockchain_utilities/blockchain_ancestry.cpp
+++ b/src/blockchain_utilities/blockchain_ancestry.cpp
@@ -37,10 +37,7 @@
 #include "common/command_line.h"
 #include "common/varint.h"
 #include "cryptonote_basic/cryptonote_boost_serialization.h"
-#include "cryptonote_core/tx_pool.h"
 #include "cryptonote_core/cryptonote_core.h"
-#include "cryptonote_core/blockchain.h"
-#include "blockchain_db/blockchain_db.h"
 #include "version.h"
 
 #undef MONERO_DEFAULT_LOG_CATEGORY
@@ -449,9 +446,7 @@ int main(int argc, char* argv[])
   // because unlike blockchain_storage constructor, which takes a pointer to
   // tx_memory_pool, Blockchain's constructor takes tx_memory_pool object.
   LOG_PRINT_L0("Initializing source blockchain (BlockchainDB)");
-  std::unique_ptr<Blockchain> core_storage;
-  tx_memory_pool m_mempool(*core_storage);
-  core_storage.reset(new Blockchain(m_mempool));
+  std::unique_ptr<BlockchainAndPool> core_storage = std::make_unique<BlockchainAndPool>();
   BlockchainDB *db = new_db();
   if (db == NULL)
   {
@@ -472,7 +467,7 @@ int main(int argc, char* argv[])
     LOG_PRINT_L0("Error opening database: " << e.what());
     return 1;
   }
-  r = core_storage->init(db, net_type);
+  r = core_storage->blockchain.init(db, net_type);
 
   CHECK_AND_ASSERT_MES(r, 1, "Failed to initialize source blockchain storage");
   LOG_PRINT_L0("Source blockchain storage initialized OK");
@@ -716,7 +711,7 @@ int main(int argc, char* argv[])
   }
 
 done:
-  core_storage->deinit();
+  core_storage->blockchain.deinit();
 
   if (opt_show_cache_stats)
   MINFO("cache: txes " << std::to_string(cached_txes*100./total_txes)
diff --git a/src/blockchain_utilities/blockchain_depth.cpp b/src/blockchain_utilities/blockchain_depth.cpp
index 6a06e0a96..f49211233 100644
--- a/src/blockchain_utilities/blockchain_depth.cpp
+++ b/src/blockchain_utilities/blockchain_depth.cpp
@@ -31,10 +31,7 @@
 #include <boost/algorithm/string.hpp>
 #include "common/command_line.h"
 #include "common/varint.h"
-#include "cryptonote_core/tx_pool.h"
 #include "cryptonote_core/cryptonote_core.h"
-#include "cryptonote_core/blockchain.h"
-#include "blockchain_db/blockchain_db.h"
 #include "version.h"
 
 #undef MONERO_DEFAULT_LOG_CATEGORY
@@ -129,16 +126,8 @@ int main(int argc, char* argv[])
   // Use Blockchain instead of lower-level BlockchainDB for two reasons:
   // 1. Blockchain has the init() method for easy setup
   // 2. exporter needs to use get_current_blockchain_height(), get_block_id_by_height(), get_block_by_hash()
-  //
-  // cannot match blockchain_storage setup above with just one line,
-  // e.g.
-  //   Blockchain* core_storage = new Blockchain(NULL);
-  // because unlike blockchain_storage constructor, which takes a pointer to
-  // tx_memory_pool, Blockchain's constructor takes tx_memory_pool object.
   LOG_PRINT_L0("Initializing source blockchain (BlockchainDB)");
-  std::unique_ptr<Blockchain> core_storage;
-  tx_memory_pool m_mempool(*core_storage);
-  core_storage.reset(new Blockchain(m_mempool));
+  std::unique_ptr<BlockchainAndPool> core_storage = std::make_unique<BlockchainAndPool>();
   BlockchainDB *db = new_db();
   if (db == NULL)
   {
@@ -159,7 +148,7 @@ int main(int argc, char* argv[])
     LOG_PRINT_L0("Error opening database: " << e.what());
     return 1;
   }
-  r = core_storage->init(db, net_type);
+  r = core_storage->blockchain.init(db, net_type);
 
   CHECK_AND_ASSERT_MES(r, 1, "Failed to initialize source blockchain storage");
   LOG_PRINT_L0("Source blockchain storage initialized OK");
@@ -327,7 +316,7 @@ done:
   LOG_PRINT_L0("Average min depth for " << start_txids.size() << " transaction(s): " << cumulative_depth/(float)depths.size());
   LOG_PRINT_L0("Median min depth for " << start_txids.size() << " transaction(s): " << epee::misc_utils::median(depths));
 
-  core_storage->deinit();
+  core_storage->blockchain.deinit();
   return 0;
 
   CATCH_ENTRY("Depth query error", 1);
diff --git a/src/blockchain_utilities/blockchain_export.cpp b/src/blockchain_utilities/blockchain_export.cpp
index 3d7b3f61a..1f8370034 100644
--- a/src/blockchain_utilities/blockchain_export.cpp
+++ b/src/blockchain_utilities/blockchain_export.cpp
@@ -29,7 +29,6 @@
 #include "bootstrap_file.h"
 #include "blocksdat_file.h"
 #include "common/command_line.h"
-#include "cryptonote_core/tx_pool.h"
 #include "cryptonote_core/cryptonote_core.h"
 #include "blockchain_db/blockchain_db.h"
 #include "version.h"
@@ -129,16 +128,8 @@ int main(int argc, char* argv[])
   // Use Blockchain instead of lower-level BlockchainDB for two reasons:
   // 1. Blockchain has the init() method for easy setup
   // 2. exporter needs to use get_current_blockchain_height(), get_block_id_by_height(), get_block_by_hash()
-  //
-  // cannot match blockchain_storage setup above with just one line,
-  // e.g.
-  //   Blockchain* core_storage = new Blockchain(NULL);
-  // because unlike blockchain_storage constructor, which takes a pointer to
-  // tx_memory_pool, Blockchain's constructor takes tx_memory_pool object.
   LOG_PRINT_L0("Initializing source blockchain (BlockchainDB)");
-  Blockchain* core_storage = NULL;
-  tx_memory_pool m_mempool(*core_storage);
-  core_storage = new Blockchain(m_mempool);
+  std::unique_ptr<BlockchainAndPool> core_storage = std::make_unique<BlockchainAndPool>();
 
   BlockchainDB* db = new_db();
   if (db == NULL)
@@ -162,9 +153,9 @@ int main(int argc, char* argv[])
     LOG_PRINT_L0("Error opening database: " << e.what());
     return 1;
   }
-  r = core_storage->init(db, opt_testnet ? cryptonote::TESTNET : opt_stagenet ? cryptonote::STAGENET : cryptonote::MAINNET);
+  r = core_storage->blockchain.init(db, opt_testnet ? cryptonote::TESTNET : opt_stagenet ? cryptonote::STAGENET : cryptonote::MAINNET);
 
-  if (core_storage->get_blockchain_pruning_seed() && !opt_blocks_dat)
+  if (core_storage->blockchain.get_blockchain_pruning_seed() && !opt_blocks_dat)
   {
     LOG_PRINT_L0("Blockchain is pruned, cannot export");
     return 1;
@@ -177,12 +168,12 @@ int main(int argc, char* argv[])
   if (opt_blocks_dat)
   {
     BlocksdatFile blocksdat;
-    r = blocksdat.store_blockchain_raw(core_storage, NULL, output_file_path, block_stop);
+    r = blocksdat.store_blockchain_raw(&core_storage->blockchain, NULL, output_file_path, block_stop);
   }
   else
   {
     BootstrapFile bootstrap;
-    r = bootstrap.store_blockchain_raw(core_storage, NULL, output_file_path, block_start, block_stop);
+    r = bootstrap.store_blockchain_raw(&core_storage->blockchain, NULL, output_file_path, block_start, block_stop);
   }
   CHECK_AND_ASSERT_MES(r, 1, "Failed to export blockchain raw data");
   LOG_PRINT_L0("Blockchain raw data exported OK");
diff --git a/src/blockchain_utilities/blockchain_prune.cpp b/src/blockchain_utilities/blockchain_prune.cpp
index 1e4b48b73..1a9618617 100644
--- a/src/blockchain_utilities/blockchain_prune.cpp
+++ b/src/blockchain_utilities/blockchain_prune.cpp
@@ -35,8 +35,6 @@
 #include "common/command_line.h"
 #include "common/pruning.h"
 #include "cryptonote_core/cryptonote_core.h"
-#include "cryptonote_core/blockchain.h"
-#include "blockchain_db/blockchain_db.h"
 #include "blockchain_db/lmdb/db_lmdb.h"
 #include "version.h"
 
@@ -562,22 +560,15 @@ int main(int argc, char* argv[])
   // Use Blockchain instead of lower-level BlockchainDB for two reasons:
   // 1. Blockchain has the init() method for easy setup
   // 2. exporter needs to use get_current_blockchain_height(), get_block_id_by_height(), get_block_by_hash()
-  //
-  // cannot match blockchain_storage setup above with just one line,
-  // e.g.
-  //   Blockchain* core_storage = new Blockchain(NULL);
-  // because unlike blockchain_storage constructor, which takes a pointer to
-  // tx_memory_pool, Blockchain's constructor takes tx_memory_pool object.
   MINFO("Initializing source blockchain (BlockchainDB)");
-  std::array<std::unique_ptr<Blockchain>, 2> core_storage;
-  Blockchain *blockchain = NULL;
-  tx_memory_pool m_mempool(*blockchain);
+  std::array<std::unique_ptr<BlockchainAndPool>, 2> core_storage{
+      std::make_unique<BlockchainAndPool>(),
+      std::make_unique<BlockchainAndPool>()};
+
   boost::filesystem::path paths[2];
   bool already_pruned = false;
   for (size_t n = 0; n < core_storage.size(); ++n)
   {
-    core_storage[n].reset(new Blockchain(m_mempool));
-
     BlockchainDB* db = new_db();
     if (db == NULL)
     {
@@ -622,12 +613,12 @@ int main(int argc, char* argv[])
       MERROR("Error opening database: " << e.what());
       return 1;
     }
-    r = core_storage[n]->init(db, net_type);
+    r = core_storage[n]->blockchain.init(db, net_type);
 
     std::string source_dest = n == 0 ? "source" : "pruned";
     CHECK_AND_ASSERT_MES(r, 1, "Failed to initialize " << source_dest << " blockchain storage");
     MINFO(source_dest << " blockchain storage initialized OK");
-    if (n == 0 && core_storage[0]->get_blockchain_pruning_seed())
+    if (n == 0 && core_storage[0]->blockchain.get_blockchain_pruning_seed())
     {
       if (!opt_copy_pruned_database)
       {
@@ -637,9 +628,9 @@ int main(int argc, char* argv[])
       already_pruned = true;
     }
   }
-  core_storage[0]->deinit();
+  core_storage[0]->blockchain.deinit();
   core_storage[0].reset(NULL);
-  core_storage[1]->deinit();
+  core_storage[1]->blockchain.deinit();
   core_storage[1].reset(NULL);
 
   MINFO("Pruning...");
diff --git a/src/blockchain_utilities/blockchain_prune_known_spent_data.cpp b/src/blockchain_utilities/blockchain_prune_known_spent_data.cpp
index 4da9c15c1..4a459dc66 100644
--- a/src/blockchain_utilities/blockchain_prune_known_spent_data.cpp
+++ b/src/blockchain_utilities/blockchain_prune_known_spent_data.cpp
@@ -30,10 +30,7 @@
 #include <boost/filesystem.hpp>
 #include "common/command_line.h"
 #include "serialization/crypto.h"
-#include "cryptonote_core/tx_pool.h"
 #include "cryptonote_core/cryptonote_core.h"
-#include "cryptonote_core/blockchain.h"
-#include "blockchain_db/blockchain_db.h"
 #include "version.h"
 
 #undef MONERO_DEFAULT_LOG_CATEGORY
@@ -160,9 +157,8 @@ int main(int argc, char* argv[])
   const std::string input = command_line::get_arg(vm, arg_input);
 
   LOG_PRINT_L0("Initializing source blockchain (BlockchainDB)");
-  std::unique_ptr<Blockchain> core_storage;
-  tx_memory_pool m_mempool(*core_storage);
-  core_storage.reset(new Blockchain(m_mempool));
+  std::unique_ptr<BlockchainAndPool> core_storage = std::make_unique<BlockchainAndPool>();
+
   BlockchainDB *db = new_db();
   if (db == NULL)
   {
@@ -182,7 +178,7 @@ int main(int argc, char* argv[])
     LOG_PRINT_L0("Error opening database: " << e.what());
     return 1;
   }
-  r = core_storage->init(db, net_type);
+  r = core_storage->blockchain.init(db, net_type);
 
   CHECK_AND_ASSERT_MES(r, 1, "Failed to initialize source blockchain storage");
   LOG_PRINT_L0("Source blockchain storage initialized OK");
@@ -280,7 +276,7 @@ int main(int argc, char* argv[])
   MINFO("Prunable outputs: " << num_prunable_outputs);
 
   LOG_PRINT_L0("Blockchain known spent data pruned OK");
-  core_storage->deinit();
+  core_storage->blockchain.deinit();
   return 0;
 
   CATCH_ENTRY("Error", 1);
diff --git a/src/blockchain_utilities/blockchain_stats.cpp b/src/blockchain_utilities/blockchain_stats.cpp
index 5e4245ebd..f65054fc5 100644
--- a/src/blockchain_utilities/blockchain_stats.cpp
+++ b/src/blockchain_utilities/blockchain_stats.cpp
@@ -31,9 +31,7 @@
 #include "common/command_line.h"
 #include "common/varint.h"
 #include "cryptonote_basic/cryptonote_boost_serialization.h"
-#include "cryptonote_core/tx_pool.h"
 #include "cryptonote_core/cryptonote_core.h"
-#include "cryptonote_core/blockchain.h"
 #include "blockchain_db/blockchain_db.h"
 #include "version.h"
 
@@ -203,9 +201,8 @@ int main(int argc, char* argv[])
   do_diff = command_line::get_arg(vm, arg_diff);
 
   LOG_PRINT_L0("Initializing source blockchain (BlockchainDB)");
-  std::unique_ptr<Blockchain> core_storage;
-  tx_memory_pool m_mempool(*core_storage);
-  core_storage.reset(new Blockchain(m_mempool));
+  std::unique_ptr<BlockchainAndPool> core_storage = std::make_unique<BlockchainAndPool>();
+
   BlockchainDB *db = new_db();
   if (db == NULL)
   {
@@ -225,7 +222,7 @@ int main(int argc, char* argv[])
     LOG_PRINT_L0("Error opening database: " << e.what());
     return 1;
   }
-  r = core_storage->init(db, net_type);
+  r = core_storage->blockchain.init(db, net_type);
 
   CHECK_AND_ASSERT_MES(r, 1, "Failed to initialize source blockchain storage");
   LOG_PRINT_L0("Source blockchain storage initialized OK");
@@ -381,7 +378,7 @@ plot 'stats.csv' index "DATA" using (timecolumn(1,"%Y-%m-%d")):4 with lines, ''
   if (currblks)
     doprint();
 
-  core_storage->deinit();
+  core_storage->blockchain.deinit();
   return 0;
 
   CATCH_ENTRY("Stats reporting error", 1);
diff --git a/src/blockchain_utilities/blockchain_usage.cpp b/src/blockchain_utilities/blockchain_usage.cpp
index a5228eb92..0b9686765 100644
--- a/src/blockchain_utilities/blockchain_usage.cpp
+++ b/src/blockchain_utilities/blockchain_usage.cpp
@@ -31,10 +31,7 @@
 #include <boost/filesystem/path.hpp>
 #include "common/command_line.h"
 #include "common/varint.h"
-#include "cryptonote_core/tx_pool.h"
 #include "cryptonote_core/cryptonote_core.h"
-#include "cryptonote_core/blockchain.h"
-#include "blockchain_db/blockchain_db.h"
 #include "version.h"
 
 #undef MONERO_DEFAULT_LOG_CATEGORY
@@ -151,9 +148,8 @@ int main(int argc, char* argv[])
   // tx_memory_pool, Blockchain's constructor takes tx_memory_pool object.
   LOG_PRINT_L0("Initializing source blockchain (BlockchainDB)");
   const std::string input = command_line::get_arg(vm, arg_input);
-  std::unique_ptr<Blockchain> core_storage;
-  tx_memory_pool m_mempool(*core_storage);
-  core_storage.reset(new Blockchain(m_mempool));
+  std::unique_ptr<BlockchainAndPool> core_storage = std::make_unique<BlockchainAndPool>();
+
   BlockchainDB* db = new_db();
   if (db == NULL)
   {
@@ -174,7 +170,7 @@ int main(int argc, char* argv[])
     LOG_PRINT_L0("Error opening database: " << e.what());
     return 1;
   }
-  r = core_storage->init(db, net_type);
+  r = core_storage->blockchain.init(db, net_type);
 
   CHECK_AND_ASSERT_MES(r, 1, "Failed to initialize source blockchain storage");
   LOG_PRINT_L0("Source blockchain storage initialized OK");
@@ -185,10 +181,10 @@ int main(int argc, char* argv[])
   std::unordered_map<uint64_t,uint64_t> indices;
 
   LOG_PRINT_L0("Reading blockchain from " << input);
-  core_storage->for_all_transactions([&](const crypto::hash &hash, const cryptonote::transaction &tx)->bool
+  core_storage->blockchain.for_all_transactions([&](const crypto::hash &hash, const cryptonote::transaction &tx)->bool
   {
     const bool coinbase = tx.vin.size() == 1 && tx.vin[0].type() == typeid(txin_gen);
-    const uint64_t height = core_storage->get_db().get_tx_block_height(hash);
+    const uint64_t height = core_storage->blockchain.get_db().get_tx_block_height(hash);
 
     // create new outputs
     for (const auto &out: tx.vout)
diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index a45d3ec60..3ad051fc3 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -113,13 +113,6 @@ namespace cryptonote
     };
 
     /**
-     * @brief Blockchain constructor
-     *
-     * @param tx_pool a reference to the transaction pool to be kept by the Blockchain
-     */
-    Blockchain(tx_memory_pool& tx_pool);
-
-    /**
      * @brief Blockchain destructor
      */
     ~Blockchain();
@@ -1236,6 +1229,13 @@ namespace cryptonote
     mutable rct_ver_cache_t m_rct_ver_cache;
 
     /**
+     * @brief Blockchain constructor
+     *
+     * @param tx_pool a reference to the transaction pool to be kept by the Blockchain
+     */
+    Blockchain(tx_memory_pool& tx_pool);
+
+    /**
      * @brief collects the keys for all outputs being "spent" as an input
      *
      * This function makes sure that each "input" in an input (mixins) exists
@@ -1608,5 +1608,7 @@ namespace cryptonote
      * @param already_generated_coins total coins mined by the network so far
      */
     void send_miner_notifications(uint64_t height, const crypto::hash &seed_hash, const crypto::hash &prev_id, uint64_t already_generated_coins);
+
+    friend class BlockchainAndPool;
   };
 }  // namespace cryptonote
diff --git a/src/cryptonote_core/blockchain_and_pool.h b/src/cryptonote_core/blockchain_and_pool.h
new file mode 100644
index 000000000..c0f607f64
--- /dev/null
+++ b/src/cryptonote_core/blockchain_and_pool.h
@@ -0,0 +1,58 @@
+// Copyright (c) 2023, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice,
+// this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+// this list
+//    of conditions and the following disclaimer in the documentation and/or
+//    other materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors
+// may be
+//    used to endorse or promote products derived from this software without
+//    specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include <memory>
+
+#include "blockchain.h"
+#include "tx_pool.h"
+
+namespace cryptonote
+{
+/**
+ * @brief Container for safely constructing Blockchain and tx_memory_pool classes
+ * 
+ * The reason for this class existing is that the constructors for both Blockchain and
+ * tx_memory_pool take a reference for tx_memory_pool and Blockchain, respectively. Because of this
+ * circular reference, it is annoying/unsafe to construct these normally. This class guarantees that
+ * we don't make any silly mistakes with pointers / dangling references.
+ */
+struct BlockchainAndPool
+{
+    Blockchain blockchain;
+    tx_memory_pool tx_pool;
+  
+    BlockchainAndPool(): blockchain(tx_pool), tx_pool(blockchain) {}
+};
+}
diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp
index dd72b3375..a5a59c892 100644
--- a/src/cryptonote_core/cryptonote_core.cpp
+++ b/src/cryptonote_core/cryptonote_core.cpp
@@ -221,8 +221,9 @@ namespace cryptonote
 
   //-----------------------------------------------------------------------------------------------
   core::core(i_cryptonote_protocol* pprotocol):
-              m_mempool(m_blockchain_storage),
-              m_blockchain_storage(m_mempool),
+              m_bap(),
+              m_mempool(m_bap.tx_pool),
+              m_blockchain_storage(m_bap.blockchain),
               m_miner(this, [this](const cryptonote::block &b, uint64_t height, const crypto::hash *seed_hash, unsigned int threads, crypto::hash &hash) {
                 return cryptonote::get_block_longhash(&m_blockchain_storage, b, hash, height, seed_hash, threads);
               }),
diff --git a/src/cryptonote_core/cryptonote_core.h b/src/cryptonote_core/cryptonote_core.h
index e0655dfa2..8108dfae0 100644
--- a/src/cryptonote_core/cryptonote_core.h
+++ b/src/cryptonote_core/cryptonote_core.h
@@ -42,8 +42,7 @@
 #include "cryptonote_protocol/enums.h"
 #include "common/download.h"
 #include "common/command_line.h"
-#include "tx_pool.h"
-#include "blockchain.h"
+#include "blockchain_and_pool.h"
 #include "cryptonote_basic/miner.h"
 #include "cryptonote_basic/connection_context.h"
 #include "warnings.h"
@@ -1098,8 +1097,9 @@ namespace cryptonote
 
      uint64_t m_test_drop_download_height = 0; //!< height under which to drop incoming blocks, if doing so
 
-     tx_memory_pool m_mempool; //!< transaction pool instance
-     Blockchain m_blockchain_storage; //!< Blockchain instance
+     BlockchainAndPool m_bap; //! Contains owned instances of Blockchain and tx_memory_pool
+     tx_memory_pool& m_mempool; //!< ref to transaction pool instance in m_bap
+     Blockchain& m_blockchain_storage; //!< ref to Blockchain instance in m_bap
 
      i_cryptonote_protocol* m_pprotocol; //!< cryptonote protocol instance
 
diff --git a/src/cryptonote_core/tx_pool.h b/src/cryptonote_core/tx_pool.h
index 6fe2eea59..47268efb6 100644
--- a/src/cryptonote_core/tx_pool.h
+++ b/src/cryptonote_core/tx_pool.h
@@ -98,14 +98,6 @@ namespace cryptonote
   {
   public:
     /**
-     * @brief Constructor
-     *
-     * @param bchs a Blockchain class instance, for getting chain info
-     */
-    tx_memory_pool(Blockchain& bchs);
-
-
-    /**
      * @copydoc add_tx(transaction&, tx_verification_context&, bool, bool, uint8_t)
      *
      * @param id the transaction's hash
@@ -489,6 +481,13 @@ namespace cryptonote
   private:
 
     /**
+     * @brief Constructor
+     *
+     * @param bchs a Blockchain class instance, for getting chain info
+     */
+    tx_memory_pool(Blockchain& bchs);
+
+    /**
      * @brief insert key images into m_spent_key_images
      *
      * @return true on success, false on error
@@ -676,6 +675,8 @@ private:
 
     //! Next timestamp that a DB check for relayable txes is allowed
     std::atomic<time_t> m_next_check;
+
+    friend class BlockchainAndPool;
   };
 }