github.com/digdeepmining/go-atheios@v1.5.13-0.20180902133602-d5687a2e6f43/core/vm/contracts.go (about)

     1  // Copyright 2014 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package vm
    18  
    19  import (
    20  	"math/big"
    21  
    22  	"github.com/atheioschain/go-atheios/common"
    23  	"github.com/atheioschain/go-atheios/crypto"
    24  	"github.com/atheioschain/go-atheios/logger"
    25  	"github.com/atheioschain/go-atheios/logger/glog"
    26  	"github.com/atheioschain/go-atheios/params"
    27  )
    28  
    29  // Precompiled contract is the basic interface for native Go contracts. The implementation
    30  // requires a deterministic gas count based on the input size of the Run method of the
    31  // contract.
    32  type PrecompiledContract interface {
    33  	RequiredGas(inputSize int) *big.Int // RequiredPrice calculates the contract gas use
    34  	Run(input []byte) []byte            // Run runs the precompiled contract
    35  }
    36  
    37  // Precompiled contains the default set of ethereum contracts
    38  var PrecompiledContracts = map[common.Address]PrecompiledContract{
    39  	common.BytesToAddress([]byte{1}): &ecrecover{},
    40  	common.BytesToAddress([]byte{2}): &sha256{},
    41  	common.BytesToAddress([]byte{3}): &ripemd160{},
    42  	common.BytesToAddress([]byte{4}): &dataCopy{},
    43  }
    44  
    45  // RunPrecompile runs and evaluate the output of a precompiled contract defined in contracts.go
    46  func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error) {
    47  	gas := p.RequiredGas(len(input))
    48  	if contract.UseGas(gas) {
    49  		ret = p.Run(input)
    50  
    51  		return ret, nil
    52  	} else {
    53  		return nil, ErrOutOfGas
    54  	}
    55  }
    56  
    57  // ECRECOVER implemented as a native contract
    58  type ecrecover struct{}
    59  
    60  func (c *ecrecover) RequiredGas(inputSize int) *big.Int {
    61  	return params.EcrecoverGas
    62  }
    63  
    64  func (c *ecrecover) Run(in []byte) []byte {
    65  	const ecRecoverInputLength = 128
    66  
    67  	in = common.RightPadBytes(in, ecRecoverInputLength)
    68  	// "in" is (hash, v, r, s), each 32 bytes
    69  	// but for ecrecover we want (r, s, v)
    70  
    71  	r := common.BytesToBig(in[64:96])
    72  	s := common.BytesToBig(in[96:128])
    73  	v := in[63] - 27
    74  
    75  	// tighter sig s values in homestead only apply to tx sigs
    76  	if common.Bytes2Big(in[32:63]).BitLen() > 0 || !crypto.ValidateSignatureValues(v, r, s, false) {
    77  		glog.V(logger.Detail).Infof("ECRECOVER error: v, r or s value invalid")
    78  		return nil
    79  	}
    80  	// v needs to be at the end for libsecp256k1
    81  	pubKey, err := crypto.Ecrecover(in[:32], append(in[64:128], v))
    82  	// make sure the public key is a valid one
    83  	if err != nil {
    84  		glog.V(logger.Detail).Infoln("ECRECOVER error: ", err)
    85  		return nil
    86  	}
    87  
    88  	// the first byte of pubkey is bitcoin heritage
    89  	return common.LeftPadBytes(crypto.Keccak256(pubKey[1:])[12:], 32)
    90  }
    91  
    92  // SHA256 implemented as a native contract
    93  type sha256 struct{}
    94  
    95  func (c *sha256) RequiredGas(inputSize int) *big.Int {
    96  	n := big.NewInt(int64(inputSize+31) / 32)
    97  	n.Mul(n, params.Sha256WordGas)
    98  	return n.Add(n, params.Sha256Gas)
    99  }
   100  func (c *sha256) Run(in []byte) []byte {
   101  	return crypto.Sha256(in)
   102  }
   103  
   104  // RIPMED160 implemented as a native contract
   105  type ripemd160 struct{}
   106  
   107  func (c *ripemd160) RequiredGas(inputSize int) *big.Int {
   108  	n := big.NewInt(int64(inputSize+31) / 32)
   109  	n.Mul(n, params.Ripemd160WordGas)
   110  	return n.Add(n, params.Ripemd160Gas)
   111  }
   112  func (c *ripemd160) Run(in []byte) []byte {
   113  	return common.LeftPadBytes(crypto.Ripemd160(in), 32)
   114  }
   115  
   116  // data copy implemented as a native contract
   117  type dataCopy struct{}
   118  
   119  func (c *dataCopy) RequiredGas(inputSize int) *big.Int {
   120  	n := big.NewInt(int64(inputSize+31) / 32)
   121  	n.Mul(n, params.IdentityWordGas)
   122  
   123  	return n.Add(n, params.IdentityGas)
   124  }
   125  func (c *dataCopy) Run(in []byte) []byte {
   126  	return in
   127  }