Exemplo n.º 1
0
// disconnectNode disconnects a stake node from itself and returns the state of
// the parent node.  The database transaction should be included if the
// UndoTicketDataSlice or tickets are nil in order to look up the undo data or
// tickets from the database.
func disconnectNode(node *Node, parentHeader wire.BlockHeader, parentUtds UndoTicketDataSlice, parentTickets []chainhash.Hash, dbTx database.Tx) (*Node, error) {
	// Edge case for the parent being the genesis block.
	if node.height == 1 {
		return genesisNode(node.params), nil
	}

	if node == nil {
		return nil, fmt.Errorf("missing stake node pointer input when " +
			"disconnecting")
	}

	// The undo ticket slice is normally stored in memory for the most
	// recent blocks and the sidechain, but it may be the case that it
	// is missing because it's in the mainchain and very old (thus
	// outside the node cache).  In this case, restore this data from
	// disk.
	if parentUtds == nil || parentTickets == nil {
		if dbTx == nil {
			return nil, stakeRuleError(ErrMissingDatabaseTx, "needed to "+
				"look up undo data in the database, but no dbtx passed")
		}

		var err error
		parentUtds, err = ticketdb.DbFetchBlockUndoData(dbTx, node.height-1)
		if err != nil {
			return nil, err
		}

		parentTickets, err = ticketdb.DbFetchNewTickets(dbTx, node.height-1)
		if err != nil {
			return nil, err
		}
	}

	restoredNode := &Node{
		height:               node.height - 1,
		liveTickets:          node.liveTickets,
		missedTickets:        node.missedTickets,
		revokedTickets:       node.revokedTickets,
		databaseUndoUpdate:   parentUtds,
		databaseBlockTickets: parentTickets,
		nextWinners:          make([]chainhash.Hash, 0),
		params:               node.params,
	}

	// Iterate through the block undo data and write all database
	// changes to the respective treap, reversing all the changes
	// added when the child block was added to the chain.
	stateBuffer := make([]byte, 0,
		(node.params.TicketsPerBlock+1)*chainhash.HashSize)
	for _, undo := range node.databaseUndoUpdate {
		var err error
		k := tickettreap.Key(undo.TicketHash)
		v := &tickettreap.Value{
			Height:  undo.TicketHeight,
			Missed:  undo.Missed,
			Revoked: undo.Revoked,
			Spent:   undo.Spent,
			Expired: undo.Expired,
		}

		switch {
		// All flags are unset; this is a newly added ticket.
		// Remove it from the list of live tickets.
		case !undo.Missed && !undo.Revoked && !undo.Spent:
			restoredNode.liveTickets, err =
				safeDelete(restoredNode.liveTickets, k)
			if err != nil {
				return nil, err
			}

		// The ticket was missed and revoked.  It needs to
		// be moved from the revoked ticket treap to the
		// missed ticket treap.
		case undo.Missed && undo.Revoked:
			v.Revoked = false
			restoredNode.revokedTickets, err =
				safeDelete(restoredNode.revokedTickets, k)
			if err != nil {
				return nil, err
			}
			restoredNode.missedTickets, err =
				safePut(restoredNode.missedTickets, k, v)
			if err != nil {
				return nil, err
			}

		// The ticket was missed and was previously live.
		// Remove it from the missed tickets bucket and
		// move it to the live tickets bucket.
		case undo.Missed && !undo.Revoked:
			// Expired tickets could never have been
			// winners.
			if !undo.Expired {
				restoredNode.nextWinners = append(restoredNode.nextWinners,
					undo.TicketHash)
				stateBuffer = append(stateBuffer,
					undo.TicketHash[:]...)
			} else {
				v.Expired = false
			}
			v.Missed = false
			restoredNode.missedTickets, err =
				safeDelete(restoredNode.missedTickets, k)
			if err != nil {
				return nil, err
			}
			restoredNode.liveTickets, err =
				safePut(restoredNode.liveTickets, k, v)
			if err != nil {
				return nil, err
			}

		// The ticket was spent.  Reinsert it into the live
		// tickets treap and add it to the list of next
		// winners.
		case undo.Spent:
			v.Spent = false
			restoredNode.nextWinners = append(restoredNode.nextWinners,
				undo.TicketHash)
			stateBuffer = append(stateBuffer, undo.TicketHash[:]...)
			restoredNode.liveTickets, err =
				safePut(restoredNode.liveTickets, k, v)
			if err != nil {
				return nil, err
			}

		default:
			return nil, stakeRuleError(ErrMemoryCorruption,
				"unknown ticket state in undo data")
		}
	}

	if node.height >= uint32(node.params.StakeValidationHeight) {
		phB, err := parentHeader.Bytes()
		if err != nil {
			return nil, err
		}
		prng := NewHash256PRNG(phB)
		_, err = findTicketIdxs(int64(restoredNode.liveTickets.Len()),
			int(node.params.TicketsPerBlock), prng)
		if err != nil {
			return nil, err
		}
		lastHash := prng.StateHash()
		stateBuffer = append(stateBuffer, lastHash[:]...)
		copy(restoredNode.finalState[:], chainhash.HashFuncB(stateBuffer)[0:6])
	}

	return restoredNode, nil
}
Exemplo n.º 2
0
// LoadBestNode is used when the blockchain is initialized, to get the initial
// stake node from the database bucket.  The blockchain must pass the height
// and the blockHash to confirm that the ticket database is on the same
// location in the blockchain as the blockchain itself.  This function also
// checks to ensure that the database has not failed the upgrade process and
// reports the current version.  Upgrades are also handled by this function,
// when they become applicable.
func LoadBestNode(dbTx database.Tx, height uint32, blockHash chainhash.Hash, header wire.BlockHeader, params *chaincfg.Params) (*Node, error) {
	info, err := ticketdb.DbFetchDatabaseInfo(dbTx)
	if err != nil {
		return nil, err
	}

	// Compare the tip and make sure it matches.
	state, err := ticketdb.DbFetchBestState(dbTx)
	if err != nil {
		return nil, err
	}
	if state.Hash != blockHash || state.Height != height {
		return nil, stakeRuleError(ErrDatabaseCorrupt, "best state corruption")
	}

	// Restore the best node treaps form the database.
	node := new(Node)
	node.height = height
	node.params = params
	node.liveTickets, err = ticketdb.DbLoadAllTickets(dbTx,
		dbnamespace.LiveTicketsBucketName)
	if err != nil {
		return nil, err
	}
	if node.liveTickets.Len() != int(state.Live) {
		return nil, stakeRuleError(ErrDatabaseCorrupt,
			fmt.Sprintf("live tickets corruption (got "+
				"%v in state but loaded %v)", int(state.Live),
				node.liveTickets.Len()))
	}
	node.missedTickets, err = ticketdb.DbLoadAllTickets(dbTx,
		dbnamespace.MissedTicketsBucketName)
	if err != nil {
		return nil, err
	}
	if node.missedTickets.Len() != int(state.Missed) {
		return nil, stakeRuleError(ErrDatabaseCorrupt,
			fmt.Sprintf("missed tickets corruption (got "+
				"%v in state but loaded %v)", int(state.Missed),
				node.missedTickets.Len()))
	}
	node.revokedTickets, err = ticketdb.DbLoadAllTickets(dbTx,
		dbnamespace.RevokedTicketsBucketName)
	if err != nil {
		return nil, err
	}
	if node.revokedTickets.Len() != int(state.Revoked) {
		return nil, stakeRuleError(ErrDatabaseCorrupt,
			fmt.Sprintf("revoked tickets corruption (got "+
				"%v in state but loaded %v)", int(state.Revoked),
				node.revokedTickets.Len()))
	}

	// Restore the node undo and new tickets data.
	node.databaseUndoUpdate, err = ticketdb.DbFetchBlockUndoData(dbTx, height)
	if err != nil {
		return nil, err
	}
	node.databaseBlockTickets, err = ticketdb.DbFetchNewTickets(dbTx, height)
	if err != nil {
		return nil, err
	}

	// Restore the next winners for the node.
	node.nextWinners = make([]chainhash.Hash, 0)
	if node.height >= uint32(node.params.StakeValidationHeight-1) {
		node.nextWinners = make([]chainhash.Hash, len(state.NextWinners))
		for i := range state.NextWinners {
			node.nextWinners[i] = state.NextWinners[i]
		}

		// Calculate the final state from the block header.
		stateBuffer := make([]byte, 0,
			(node.params.TicketsPerBlock+1)*chainhash.HashSize)
		for _, ticketHash := range node.nextWinners {
			stateBuffer = append(stateBuffer, ticketHash[:]...)
		}
		hB, err := header.Bytes()
		if err != nil {
			return nil, err
		}
		prng := NewHash256PRNG(hB)
		_, err = findTicketIdxs(int64(node.liveTickets.Len()),
			int(node.params.TicketsPerBlock), prng)
		if err != nil {
			return nil, err
		}
		lastHash := prng.StateHash()
		stateBuffer = append(stateBuffer, lastHash[:]...)
		copy(node.finalState[:], chainhash.HashFuncB(stateBuffer)[0:6])
	}

	log.Infof("Stake database version %v loaded", info.Version)

	return node, nil
}