path: root/core/genesis.go

// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package core

import (
    "errors"
    "fmt"
    "math/big"
    "strings"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/common/hexutil"
    "github.com/ethereum/go-ethereum/common/math"
    "github.com/ethereum/go-ethereum/core/state"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/ethdb"
    "github.com/ethereum/go-ethereum/log"
    "github.com/ethereum/go-ethereum/params"
    "github.com/ethereum/go-ethereum/rlp"
)

//go:generate gencodec -type Genesis -field-override genesisSpecMarshaling -out gen_genesis.go
//go:generate gencodec -type GenesisAccount -field-override genesisAccountMarshaling -out gen_genesis_account.go

var errGenesisNoConfig = errors.New("genesis has no chain configuration")

// Genesis specifies the header fields, state of a genesis block. It also defines hard
// fork switch-over blocks through the chain configuration.
type Genesis struct {
    Config     *params.ChainConfig `json:"config"`
    Nonce      uint64              `json:"nonce"`
    Timestamp  uint64              `json:"timestamp"`
    ParentHash common.Hash         `json:"parentHash"`
    ExtraData  []byte              `json:"extraData"`
    GasLimit   uint64              `json:"gasLimit"   gencodec:"required"`
    Difficulty *big.Int            `json:"difficulty" gencodec:"required"`
    Mixhash    common.Hash         `json:"mixHash"`
    Coinbase   common.Address      `json:"coinbase"`
    Alloc      GenesisAlloc        `json:"alloc"      gencodec:"required"`
}

// GenesisAlloc specifies the initial state that is part of the genesis block.
type GenesisAlloc map[common.Address]GenesisAccount

// GenesisAccount is an account in the state of the genesis block.
type GenesisAccount struct {
    Code    []byte                      `json:"code,omitempty"`
    Storage map[common.Hash]common.Hash `json:"storage,omitempty"`
    Balance *big.Int                    `json:"balance" gencodec:"required"`
    Nonce   uint64                      `json:"nonce,omitempty"`
}

// field type overrides for gencodec
type genesisSpecMarshaling struct {
    Nonce      math.HexOrDecimal64
    Timestamp  math.HexOrDecimal64
    ExtraData  hexutil.Bytes
    GasLimit   math.HexOrDecimal64
    Difficulty *math.HexOrDecimal256
    Alloc      map[common.UnprefixedAddress]GenesisAccount
}
type genesisAccountMarshaling struct {
    Code    hexutil.Bytes
    Balance *math.HexOrDecimal256
    Nonce   math.HexOrDecimal64
}

// GenesisMismatchError is raised when trying to overwrite an existing
// genesis block with an incompatible one.
type GenesisMismatchError struct {
    Stored, New common.Hash
}

func (e *GenesisMismatchError) Error() string {
    return fmt.Sprintf("wrong genesis block in database (have %x, new %x)", e.Stored[:8], e.New[:8])
}

// SetupGenesisBlock writes or updates the genesis block in db.
// The block that will be used is:
//
//                          genesis == nil       genesis != nil
//                       +------------------------------------------
//     db has no genesis |  main-net default  |  genesis
//     db has genesis    |  from DB           |  genesis (if compatible)
//
// The stored chain configuration will be updated if it is compatible (i.e. does not
// specify a fork block below the local head block). In case of a conflict, the
// error is a *params.ConfigCompatError and the new, unwritten config is returned.
//
// The returned chain configuration is never nil.
func SetupGenesisBlock(db ethdb.Database, genesis *Genesis) (*params.ChainConfig, common.Hash, error) {
    if genesis != nil && genesis.Config == nil {
        return params.AllProtocolChanges, common.Hash{}, errGenesisNoConfig
    }

    // Just commit the new block if there is no stored genesis block.
    stored := GetCanonicalHash(db, 0)
    if (stored == common.Hash{}) {
        if genesis == nil {
            log.Info("Writing default main-net genesis block")
            genesis = DefaultGenesisBlock()
        } else {
            log.Info("Writing custom genesis block")
        }
        block, err := genesis.Commit(db)
        return genesis.Config, block.Hash(), err
    }

    // Check whether the genesis block is already written.
    if genesis != nil {
        block, _ := genesis.ToBlock()
        hash := block.Hash()
        if hash != stored {
            return genesis.Config, block.Hash(), &GenesisMismatchError{stored, hash}
        }
    }

    // Get the existing chain configuration.
    newcfg := genesis.configOrDefault(stored)
    storedcfg, err := GetChainConfig(db, stored)
    if err != nil {
        if err == ChainConfigNotFoundErr {
            // This case happens if a genesis write was interrupted.
            log.Warn("Found genesis block without chain config")
            err = WriteChainConfig(db, stored, newcfg)
        }
        return newcfg, stored, err
    }
    // Special case: don't change the existing config of a non-mainnet chain if no new
    // config is supplied. These chains would get AllProtocolChanges (and a compat error)
    // if we just continued here.
    if genesis == nil && stored != params.MainNetGenesisHash {
        return storedcfg, stored, nil
    }

    // Check config compatibility and write the config. Compatibility errors
    // are returned to the caller unless we're already at block zero.
    height := GetBlockNumber(db, GetHeadHeaderHash(db))
    if height == missingNumber {
        return newcfg, stored, fmt.Errorf("missing block number for head header hash")
    }
    compatErr := storedcfg.CheckCompatible(newcfg, height)
    if compatErr != nil && height != 0 && compatErr.RewindTo != 0 {
        return newcfg, stored, compatErr
    }
    return newcfg, stored, WriteChainConfig(db, stored, newcfg)
}

func (g *Genesis) configOrDefault(ghash common.Hash) *params.ChainConfig {
    switch {
    case g != nil:
        return g.Config
    case ghash == params.MainNetGenesisHash:
        return params.MainnetChainConfig
    case ghash == params.TestNetGenesisHash:
        return params.TestnetChainConfig
    default:
        return params.AllProtocolChanges
    }
}

// ToBlock creates the block and state of a genesis specification.
func (g *Genesis) ToBlock() (*types.Block, *state.StateDB) {
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, db)
    for addr, account := range g.Alloc {
        statedb.AddBalance(addr, account.Balance)
        statedb.SetCode(addr, account.Code)
        statedb.SetNonce(addr, account.Nonce)
        for key, value := range account.Storage {
            statedb.SetState(addr, key, value)
        }
    }
    root := statedb.IntermediateRoot(false)
    head := &types.Header{
        Nonce:      types.EncodeNonce(g.Nonce),
        Time:       new(big.Int).SetUint64(g.Timestamp),
        ParentHash: g.ParentHash,
        Extra:      g.ExtraData,
        GasLimit:   new(big.Int).SetUint64(g.GasLimit),
        Difficulty: g.Difficulty,
        MixDigest:  g.Mixhash,
        Coinbase:   g.Coinbase,
        Root:       root,
    }
    if g.GasLimit == 0 {
        head.GasLimit = params.GenesisGasLimit
    }
    if g.Difficulty == nil {
        head.Difficulty = params.GenesisDifficulty
    }
    return types.NewBlock(head, nil, nil, nil), statedb
}

// Commit writes the block and state of a genesis specification to the database.
// The block is committed as the canonical head block.
func (g *Genesis) Commit(db ethdb.Database) (*types.Block, error) {
    block, statedb := g.ToBlock()
    if _, err := statedb.CommitTo(db, false); err != nil {
        return nil, fmt.Errorf("cannot write state: %v", err)
    }
    if err := WriteTd(db, block.Hash(), block.NumberU64(), g.Difficulty); err != nil {
        return nil, err
    }
    if err := WriteBlock(db, block); err != nil {
        return nil, err
    }
    if err := WriteBlockReceipts(db, block.Hash(), block.NumberU64(), nil); err != nil {
        return nil, err
    }
    if err := WriteCanonicalHash(db, block.Hash(), block.NumberU64()); err != nil {
        return nil, err
    }
    if err := WriteHeadBlockHash(db, block.Hash()); err != nil {
        return nil, err
    }
    if err := WriteHeadHeaderHash(db, block.Hash()); err != nil {
        return nil, err
    }
    config := g.Config
    if config == nil {
        config = params.AllProtocolChanges
    }
    return block, WriteChainConfig(db, block.Hash(), config)
}

// MustCommit writes the genesis block and state to db, panicking on error.
// The block is committed as the canonical head block.
func (g *Genesis) MustCommit(db ethdb.Database) *types.Block {
    block, err := g.Commit(db)
    if err != nil {
        panic(err)
    }
    return block
}

// GenesisBlockForTesting creates and writes a block in which addr has the given wei balance.
func GenesisBlockForTesting(db ethdb.Database, addr common.Address, balance *big.Int) *types.Block {
    g := Genesis{Alloc: GenesisAlloc{addr: {Balance: balance}}}
    return g.MustCommit(db)
}

// DefaultGenesisBlock returns the Ethereum main net genesis block.
func DefaultGenesisBlock() *Genesis {
    return &Genesis{
        Config:     params.MainnetChainConfig,
        Nonce:      66,
        ExtraData:  hexutil.MustDecode("0x11bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa"),
        GasLimit:   5000,
        Difficulty: big.NewInt(17179869184),
        Alloc:      decodePrealloc(mainnetAllocData),
    }
}

// DefaultTestnetGenesisBlock returns the Ropsten network genesis block.
func DefaultTestnetGenesisBlock() *Genesis {
    return &Genesis{
        Config:     params.TestnetChainConfig,
        Nonce:      66,
        ExtraData:  hexutil.MustDecode("0x3535353535353535353535353535353535353535353535353535353535353535"),
        GasLimit:   16777216,
        Difficulty: big.NewInt(1048576),
        Alloc:      decodePrealloc(testnetAllocData),
    }
}

// DevGenesisBlock returns the 'geth --dev' genesis block.
func DevGenesisBlock() *Genesis {
    return &Genesis{
        Config:     params.AllProtocolChanges,
        Nonce:      42,
        GasLimit:   4712388,
        Difficulty: big.NewInt(131072),
        Alloc:      decodePrealloc(devAllocData),
    }
}

func decodePrealloc(data string) GenesisAlloc {
    var p []struct{ Addr, Balance *big.Int }
    if err := rlp.NewStream(strings.NewReader(data), 0).Decode(&p); err != nil {
        panic(err)
    }
    ga := make(GenesisAlloc, len(p))
    for _, account := range p {
        ga[common.BigToAddress(account.Addr)] = GenesisAccount{Balance: account.Balance}
    }
    return ga
}