blockchain: keep alternative blocks in LMDB

Alternative blocks are cleared on startup unless --keep-alt-blocks
is passed on the command line

1 files changed, 155 insertions, 0 deletions

diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 340434888..d17eebee4 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -194,6 +194,8 @@ namespace
  * txpool_meta      txn hash     txn metadata
  * txpool_blob      txn hash     txn blob
  *
+ * alt_blocks       block hash   {block data, block blob}
+ *
  * Note: where the data items are of uniform size, DUPFIXED tables have
  * been used to save space. In most of these cases, a dummy "zerokval"
  * key is used when accessing the table; the Key listed above will be
@@ -221,6 +223,8 @@ const char* const LMDB_SPENT_KEYS = "spent_keys";
 const char* const LMDB_TXPOOL_META = "txpool_meta";
 const char* const LMDB_TXPOOL_BLOB = "txpool_blob";
 
+const char* const LMDB_ALT_BLOCKS = "alt_blocks";
+
 const char* const LMDB_HF_STARTING_HEIGHTS = "hf_starting_heights";
 const char* const LMDB_HF_VERSIONS = "hf_versions";
 
@@ -1400,6 +1404,8 @@ void BlockchainLMDB::open(const std::string& filename, const int db_flags)
   lmdb_db_open(txn, LMDB_TXPOOL_META, MDB_CREATE, m_txpool_meta, "Failed to open db handle for m_txpool_meta");
   lmdb_db_open(txn, LMDB_TXPOOL_BLOB, MDB_CREATE, m_txpool_blob, "Failed to open db handle for m_txpool_blob");
 
+  lmdb_db_open(txn, LMDB_ALT_BLOCKS, MDB_CREATE, m_alt_blocks, "Failed to open db handle for m_alt_blocks");
+
   // this subdb is dropped on sight, so it may not be present when we open the DB.
   // Since we use MDB_CREATE, we'll get an exception if we open read-only and it does not exist.
   // So we don't open for read-only, and also not drop below. It is not used elsewhere.
@@ -1423,6 +1429,7 @@ void BlockchainLMDB::open(const std::string& filename, const int db_flags)
 
   mdb_set_compare(txn, m_txpool_meta, compare_hash32);
   mdb_set_compare(txn, m_txpool_blob, compare_hash32);
+  mdb_set_compare(txn, m_alt_blocks, compare_hash32);
   mdb_set_compare(txn, m_properties, compare_string);
 
   if (!(mdb_flags & MDB_RDONLY))
@@ -2241,6 +2248,50 @@ bool BlockchainLMDB::for_all_txpool_txes(std::function<bool(const crypto::hash&,
   return ret;
 }
 
+bool BlockchainLMDB::for_all_alt_blocks(std::function<bool(const crypto::hash&, const alt_block_data_t&, const cryptonote::blobdata*)> f, bool include_blob) const
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+
+  TXN_PREFIX_RDONLY();
+  RCURSOR(alt_blocks);
+
+  MDB_val k;
+  MDB_val v;
+  bool ret = true;
+
+  MDB_cursor_op op = MDB_FIRST;
+  while (1)
+  {
+    int result = mdb_cursor_get(m_cur_alt_blocks, &k, &v, op);
+    op = MDB_NEXT;
+    if (result == MDB_NOTFOUND)
+      break;
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Failed to enumerate alt blocks: ", result).c_str()));
+    const crypto::hash &blkid = *(const crypto::hash*)k.mv_data;
+    if (v.mv_size < sizeof(alt_block_data_t))
+      throw0(DB_ERROR("alt_blocks record is too small"));
+    const alt_block_data_t *data = (const alt_block_data_t*)v.mv_data;
+    const cryptonote::blobdata *passed_bd = NULL;
+    cryptonote::blobdata bd;
+    if (include_blob)
+    {
+      bd.assign(reinterpret_cast<const char*>(v.mv_data) + sizeof(alt_block_data_t), v.mv_size - sizeof(alt_block_data_t));
+      passed_bd = &bd;
+    }
+
+    if (!f(blkid, *data, passed_bd)) {
+      ret = false;
+      break;
+    }
+  }
+
+  TXN_POSTFIX_RDONLY();
+
+  return ret;
+}
+
 bool BlockchainLMDB::block_exists(const crypto::hash& h, uint64_t *height) const
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
@@ -4062,6 +4113,110 @@ uint8_t BlockchainLMDB::get_hard_fork_version(uint64_t height) const
   return ret;
 }
 
+void BlockchainLMDB::add_alt_block(const crypto::hash &blkid, const cryptonote::alt_block_data_t &data, const cryptonote::blobdata &blob)
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+  mdb_txn_cursors *m_cursors = &m_wcursors;
+
+  CURSOR(alt_blocks)
+
+  MDB_val k = {sizeof(blkid), (void *)&blkid};
+  const size_t val_size = sizeof(alt_block_data_t) + blob.size();
+  std::unique_ptr<char[]> val(new char[val_size]);
+  memcpy(val.get(), &data, sizeof(alt_block_data_t));
+  memcpy(val.get() + sizeof(alt_block_data_t), blob.data(), blob.size());
+  MDB_val v = {val_size, (void *)val.get()};
+  if (auto result = mdb_cursor_put(m_cur_alt_blocks, &k, &v, MDB_NODUPDATA)) {
+    if (result == MDB_KEYEXIST)
+      throw1(DB_ERROR("Attempting to add alternate block that's already in the db"));
+    else
+      throw1(DB_ERROR(lmdb_error("Error adding alternate block to db transaction: ", result).c_str()));
+  }
+}
+
+bool BlockchainLMDB::get_alt_block(const crypto::hash &blkid, alt_block_data_t *data, cryptonote::blobdata *blob)
+{
+  LOG_PRINT_L3("BlockchainLMDB:: " << __func__);
+  check_open();
+
+  TXN_PREFIX_RDONLY();
+  RCURSOR(alt_blocks);
+
+  MDB_val_set(k, blkid);
+  MDB_val v;
+  int result = mdb_cursor_get(m_cur_alt_blocks, &k, &v, MDB_SET);
+  if (result == MDB_NOTFOUND)
+    return false;
+
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Error attempting to retrieve alternate block " + epee::string_tools::pod_to_hex(blkid) + " from the db: ", result).c_str()));
+  if (v.mv_size < sizeof(alt_block_data_t))
+    throw0(DB_ERROR("Record size is less than expected"));
+
+  const alt_block_data_t *ptr = (const alt_block_data_t*)v.mv_data;
+  if (data)
+    *data = *ptr;
+  if (blob)
+    blob->assign((const char*)(ptr + 1), v.mv_size - sizeof(alt_block_data_t));
+
+  TXN_POSTFIX_RDONLY();
+  return true;
+}
+
+void BlockchainLMDB::remove_alt_block(const crypto::hash &blkid)
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+  mdb_txn_cursors *m_cursors = &m_wcursors;
+
+  CURSOR(alt_blocks)
+
+  MDB_val k = {sizeof(blkid), (void *)&blkid};
+  MDB_val v;
+  int result = mdb_cursor_get(m_cur_alt_blocks, &k, &v, MDB_SET);
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Error locating alternate block " + epee::string_tools::pod_to_hex(blkid) + " in the db: ", result).c_str()));
+  result = mdb_cursor_del(m_cur_alt_blocks, 0);
+  if (result)
+    throw0(DB_ERROR(lmdb_error("Error deleting alternate block " + epee::string_tools::pod_to_hex(blkid) + " from the db: ", result).c_str()));
+}
+
+uint64_t BlockchainLMDB::get_alt_block_count()
+{
+  LOG_PRINT_L3("BlockchainLMDB:: " << __func__);
+  check_open();
+
+  TXN_PREFIX_RDONLY();
+  RCURSOR(alt_blocks);
+
+  MDB_stat db_stats;
+  int result = mdb_stat(m_txn, m_alt_blocks, &db_stats);
+  uint64_t count = 0;
+  if (result != MDB_NOTFOUND)
+  {
+    if (result)
+      throw0(DB_ERROR(lmdb_error("Failed to query m_alt_blocks: ", result).c_str()));
+    count = db_stats.ms_entries;
+  }
+  TXN_POSTFIX_RDONLY();
+  return count;
+}
+
+void BlockchainLMDB::drop_alt_blocks()
+{
+  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
+  check_open();
+
+  TXN_PREFIX(0);
+
+  auto result = mdb_drop(*txn_ptr, m_alt_blocks, 0);
+  if (result)
+    throw1(DB_ERROR(lmdb_error("Error dropping alternative blocks: ", result).c_str()));
+
+  TXN_POSTFIX_SUCCESS();
+}
+
 bool BlockchainLMDB::is_read_only() const
 {
   unsigned int flags;