path: root/cmd/puppeth/wizard_genesis.go

// Copyright 2017 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

package main

import (
    "bytes"
    "fmt"
    "math/big"
    "math/rand"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core"
    "github.com/ethereum/go-ethereum/log"
    "github.com/ethereum/go-ethereum/params"
)

// makeGenesis creates a new genesis struct based on some user input.
func (w *wizard) makeGenesis() {
    // Construct a default genesis block
    genesis := &core.Genesis{
        Timestamp:  uint64(time.Now().Unix()),
        GasLimit:   4700000,
        Difficulty: big.NewInt(1048576),
        Alloc:      make(core.GenesisAlloc),
        Config: &params.ChainConfig{
            HomesteadBlock: big.NewInt(1),
            EIP150Block:    big.NewInt(2),
            EIP155Block:    big.NewInt(3),
            EIP158Block:    big.NewInt(3),
        },
    }
    // Figure out which consensus engine to choose
    fmt.Println()
    fmt.Println("Which consensus engine to use? (default = clique)")
    fmt.Println(" 1. Ethash - proof-of-work")
    fmt.Println(" 2. Clique - proof-of-authority")

    choice := w.read()
    switch {
    case choice == "1":
        // In case of ethash, we're pretty much done
        genesis.Config.Ethash = new(params.EthashConfig)
        genesis.ExtraData = make([]byte, 32)

    case choice == "" || choice == "2":
        // In the case of clique, configure the consensus parameters
        genesis.Difficulty = big.NewInt(1)
        genesis.Config.Clique = &params.CliqueConfig{
            Period: 15,
            Epoch:  30000,
        }
        fmt.Println()
        fmt.Println("How many seconds should blocks take? (default = 15)")
        genesis.Config.Clique.Period = uint64(w.readDefaultInt(15))

        // We also need the initial list of signers
        fmt.Println()
        fmt.Println("Which accounts are allowed to seal? (mandatory at least one)")

        var signers []common.Address
        for {
            if address := w.readAddress(); address != nil {
                signers = append(signers, *address)
                continue
            }
            if len(signers) > 0 {
                break
            }
        }
        // Sort the signers and embed into the extra-data section
        for i := 0; i < len(signers); i++ {
            for j := i + 1; j < len(signers); j++ {
                if bytes.Compare(signers[i][:], signers[j][:]) > 0 {
                    signers[i], signers[j] = signers[j], signers[i]
                }
            }
        }
        genesis.ExtraData = make([]byte, 32+len(signers)*common.AddressLength+65)
        for i, signer := range signers {
            copy(genesis.ExtraData[32+i*common.AddressLength:], signer[:])
        }

    default:
        log.Crit("Invalid consensus engine choice", "choice", choice)
    }
    // Consensus all set, just ask for initial funds and go
    fmt.Println()
    fmt.Println("Which accounts should be pre-funded? (advisable at least one)")
    for {
        // Read the address of the account to fund
        if address := w.readAddress(); address != nil {
            genesis.Alloc[*address] = core.GenesisAccount{
                Balance: new(big.Int).Lsh(big.NewInt(1), 256-7), // 2^256 / 128 (allow many pre-funds without balance overflows)
            }
            continue
        }
        break
    }
    // Add a batch of precompile balances to avoid them getting deleted
    for i := int64(0); i < 256; i++ {
        genesis.Alloc[common.BigToAddress(big.NewInt(i))] = core.GenesisAccount{Balance: big.NewInt(1)}
    }
    fmt.Println()

    // Query the user for some custom extras
    fmt.Println()
    fmt.Println("Specify your chain/network ID if you want an explicit one (default = random)")
    genesis.Config.ChainId = new(big.Int).SetUint64(uint64(w.readDefaultInt(rand.Intn(65536))))

    fmt.Println()
    fmt.Println("Anything fun to embed into the genesis block? (max 32 bytes)")

    extra := w.read()
    if len(extra) > 32 {
        extra = extra[:32]
    }
    genesis.ExtraData = append([]byte(extra), genesis.ExtraData[len(extra):]...)

    // All done, store the genesis and flush to disk
    w.conf.genesis = genesis
}