Skip to content

Commit

Permalink
Add 'transfer' precompiled contract (ethereum#75)
Browse files Browse the repository at this point in the history 
* Add 'transfer' precompiled contract
  • Loading branch information
@asaj
asaj authored Oct 24, 2018
1 parent 45bb271 commit 6cdda73
Show file tree
Hide file tree
Showing 3 changed files with 40 additions and 16 deletions.
50 changes: 37 additions & 13 deletions core/vm/contracts.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,9 +19,11 @@ package vm
import (
"crypto/sha256"
"errors"
"fmt"
"math/big"

"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/types"
"github.com/ethereum/go-ethereum/crypto"
Expand All @@ -35,8 +37,8 @@ import (
// requires a deterministic gas count based on the input size of the Run method of the
// contract.
type PrecompiledContract interface {
RequiredGas(input []byte) uint64 // RequiredPrice calculates the contract gas use
Run(input []byte) ([]byte, error) // Run runs the precompiled contract
RequiredGas(input []byte) uint64 // RequiredPrice calculates the contract gas use
Run(input []byte, evm *EVM) ([]byte, error) // Run runs the precompiled contract
}

// PrecompiledContractsHomestead contains the default set of pre-compiled Ethereum
Expand All @@ -50,6 +52,7 @@ var PrecompiledContractsHomestead = map[common.Address]PrecompiledContract{

var CeloPrecompiledContractsAddressOffset = byte(0xff)
var requestVerificationAddress = common.BytesToAddress(append([]byte{0}, CeloPrecompiledContractsAddressOffset))
var transferAddress = common.BytesToAddress(append([]byte{0}, (CeloPrecompiledContractsAddressOffset - 2)))

// PrecompiledContractsByzantium contains the default set of pre-compiled Ethereum
// contracts used in the Byzantium release.
Expand All @@ -65,13 +68,14 @@ var PrecompiledContractsByzantium = map[common.Address]PrecompiledContract{

// Celo Precompiled Contracts
requestVerificationAddress: &requestVerification{},
transferAddress: &transfer{},
}

// RunPrecompiledContract runs and evaluates the output of a precompiled contract.
func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error) {
func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract, evm *EVM) (ret []byte, err error) {
gas := p.RequiredGas(input)
if contract.UseGas(gas) {
return p.Run(input)
return p.Run(input, evm)
}
return nil, ErrOutOfGas
}
Expand All @@ -83,7 +87,7 @@ func (c *ecrecover) RequiredGas(input []byte) uint64 {
return params.EcrecoverGas
}

func (c *ecrecover) Run(input []byte) ([]byte, error) {
func (c *ecrecover) Run(input []byte, evm *EVM) ([]byte, error) {
const ecRecoverInputLength = 128

input = common.RightPadBytes(input, ecRecoverInputLength)
Expand Down Expand Up @@ -119,7 +123,7 @@ type sha256hash struct{}
func (c *sha256hash) RequiredGas(input []byte) uint64 {
return uint64(len(input)+31)/32*params.Sha256PerWordGas + params.Sha256BaseGas
}
func (c *sha256hash) Run(input []byte) ([]byte, error) {
func (c *sha256hash) Run(input []byte, evm *EVM) ([]byte, error) {
h := sha256.Sum256(input)
return h[:], nil
}
Expand All @@ -134,7 +138,7 @@ type ripemd160hash struct{}
func (c *ripemd160hash) RequiredGas(input []byte) uint64 {
return uint64(len(input)+31)/32*params.Ripemd160PerWordGas + params.Ripemd160BaseGas
}
func (c *ripemd160hash) Run(input []byte) ([]byte, error) {
func (c *ripemd160hash) Run(input []byte, evm *EVM) ([]byte, error) {
ripemd := ripemd160.New()
ripemd.Write(input)
return common.LeftPadBytes(ripemd.Sum(nil), 32), nil
Expand All @@ -150,7 +154,7 @@ type dataCopy struct{}
func (c *dataCopy) RequiredGas(input []byte) uint64 {
return uint64(len(input)+31)/32*params.IdentityPerWordGas + params.IdentityBaseGas
}
func (c *dataCopy) Run(in []byte) ([]byte, error) {
func (c *dataCopy) Run(in []byte, evm *EVM) ([]byte, error) {
return in, nil
}

Expand Down Expand Up @@ -231,7 +235,7 @@ func (c *bigModExp) RequiredGas(input []byte) uint64 {
return gas.Uint64()
}

func (c *bigModExp) Run(input []byte) ([]byte, error) {
func (c *bigModExp) Run(input []byte, evm *EVM) ([]byte, error) {
var (
baseLen = new(big.Int).SetBytes(getData(input, 0, 32)).Uint64()
expLen = new(big.Int).SetBytes(getData(input, 32, 32)).Uint64()
Expand Down Expand Up @@ -287,7 +291,7 @@ func (c *bn256Add) RequiredGas(input []byte) uint64 {
return params.Bn256AddGas
}

func (c *bn256Add) Run(input []byte) ([]byte, error) {
func (c *bn256Add) Run(input []byte, evm *EVM) ([]byte, error) {
x, err := newCurvePoint(getData(input, 0, 64))
if err != nil {
return nil, err
Expand All @@ -309,7 +313,7 @@ func (c *bn256ScalarMul) RequiredGas(input []byte) uint64 {
return params.Bn256ScalarMulGas
}

func (c *bn256ScalarMul) Run(input []byte) ([]byte, error) {
func (c *bn256ScalarMul) Run(input []byte, evm *EVM) ([]byte, error) {
p, err := newCurvePoint(getData(input, 0, 64))
if err != nil {
return nil, err
Expand Down Expand Up @@ -338,7 +342,7 @@ func (c *bn256Pairing) RequiredGas(input []byte) uint64 {
return params.Bn256PairingBaseGas + uint64(len(input)/192)*params.Bn256PairingPerPointGas
}

func (c *bn256Pairing) Run(input []byte) ([]byte, error) {
func (c *bn256Pairing) Run(input []byte, evm *EVM) ([]byte, error) {
// Handle some corner cases cheaply
if len(input)%192 > 0 {
return nil, errBadPairingInput
Expand Down Expand Up @@ -377,7 +381,7 @@ func (c *requestVerification) RequiredGas(input []byte) uint64 {
}

// Ensures that the input is parsable as a VerificationRequest.
func (c *requestVerification) Run(input []byte) ([]byte, error) {
func (c *requestVerification) Run(input []byte, evm *EVM) ([]byte, error) {
_, err := types.DecodeVerificationRequest(input)
if err != nil {
log.Error("[Celo] Unable to decode verification request", "err", err)
Expand All @@ -386,3 +390,23 @@ func (c *requestVerification) Run(input []byte) ([]byte, error) {
return input, nil
}
}

// Native transfer contract to make Celo Gold ERC20 compatible.
type transfer struct{}

func (c *transfer) RequiredGas(input []byte) uint64 {
return params.TxGas
}

// Ensures that the input is parsable as a VerificationRequest.
func (c *transfer) Run(input []byte, evm *EVM) ([]byte, error) {
from := common.BytesToAddress(input[0:32])
to := common.BytesToAddress(input[32:64])
var parsed bool
value, parsed := math.ParseBig256(hexutil.Encode(input[64:96]))
if !parsed {
return nil, fmt.Errorf("Error parsing transfer: unable to parse value from " + hexutil.Encode(input[64:96]))
}
evm.Transfer(evm.StateDB, from, to, value)
return input, nil
}
4 changes: 2 additions & 2 deletions core/vm/contracts_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -342,7 +342,7 @@ func testPrecompiled(addr string, test precompiledTest, t *testing.T) {
contract := NewContract(AccountRef(common.HexToAddress("1337")),
nil, new(big.Int), p.RequiredGas(in))
t.Run(fmt.Sprintf("%s-Gas=%d", test.name, contract.Gas), func(t *testing.T) {
if res, err := RunPrecompiledContract(p, in, contract); err != nil {
if res, err := RunPrecompiledContract(p, in, contract, nil); err != nil {
t.Error(err)
} else if common.Bytes2Hex(res) != test.expected {
t.Errorf("Expected %v, got %v", test.expected, common.Bytes2Hex(res))
Expand Down Expand Up @@ -371,7 +371,7 @@ func benchmarkPrecompiled(addr string, test precompiledTest, bench *testing.B) {
for i := 0; i < bench.N; i++ {
contract.Gas = reqGas
copy(data, in)
res, err = RunPrecompiledContract(p, data, contract)
res, err = RunPrecompiledContract(p, data, contract, nil)
}
bench.StopTimer()
//Check if it is correct
Expand Down
2 changes: 1 addition & 1 deletion core/vm/evm.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,7 @@ func run(evm *EVM, contract *Contract, input []byte, readOnly bool) ([]byte, err
precompiles = PrecompiledContractsByzantium
}
if p := precompiles[*contract.CodeAddr]; p != nil {
return RunPrecompiledContract(p, input, contract)
return RunPrecompiledContract(p, input, contract, evm)
}
}
for _, interpreter := range evm.interpreters {
Expand Down

0 comments on commit 6cdda73

Please sign in to comment.