github.com/anthdm/go-ethereum@v1.8.4-0.20180412101906-60516c83b011/core/vm/runtime/runtime.go (about)

     1  // Copyright 2015 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 runtime
    18  
    19  import (
    20  	"math"
    21  	"math/big"
    22  	"time"
    23  
    24  	"github.com/ethereum/go-ethereum/common"
    25  	"github.com/ethereum/go-ethereum/core/state"
    26  	"github.com/ethereum/go-ethereum/core/vm"
    27  	"github.com/ethereum/go-ethereum/crypto"
    28  	"github.com/ethereum/go-ethereum/ethdb"
    29  	"github.com/ethereum/go-ethereum/params"
    30  )
    31  
    32  // Config is a basic type specifying certain configuration flags for running
    33  // the EVM.
    34  type Config struct {
    35  	ChainConfig *params.ChainConfig
    36  	Difficulty  *big.Int
    37  	Origin      common.Address
    38  	Coinbase    common.Address
    39  	BlockNumber *big.Int
    40  	Time        *big.Int
    41  	GasLimit    uint64
    42  	GasPrice    *big.Int
    43  	Value       *big.Int
    44  	Debug       bool
    45  	EVMConfig   vm.Config
    46  
    47  	State     *state.StateDB
    48  	GetHashFn func(n uint64) common.Hash
    49  }
    50  
    51  // sets defaults on the config
    52  func setDefaults(cfg *Config) {
    53  	if cfg.ChainConfig == nil {
    54  		cfg.ChainConfig = &params.ChainConfig{
    55  			ChainId:        big.NewInt(1),
    56  			HomesteadBlock: new(big.Int),
    57  			DAOForkBlock:   new(big.Int),
    58  			DAOForkSupport: false,
    59  			EIP150Block:    new(big.Int),
    60  			EIP155Block:    new(big.Int),
    61  			EIP158Block:    new(big.Int),
    62  		}
    63  	}
    64  
    65  	if cfg.Difficulty == nil {
    66  		cfg.Difficulty = new(big.Int)
    67  	}
    68  	if cfg.Time == nil {
    69  		cfg.Time = big.NewInt(time.Now().Unix())
    70  	}
    71  	if cfg.GasLimit == 0 {
    72  		cfg.GasLimit = math.MaxUint64
    73  	}
    74  	if cfg.GasPrice == nil {
    75  		cfg.GasPrice = new(big.Int)
    76  	}
    77  	if cfg.Value == nil {
    78  		cfg.Value = new(big.Int)
    79  	}
    80  	if cfg.BlockNumber == nil {
    81  		cfg.BlockNumber = new(big.Int)
    82  	}
    83  	if cfg.GetHashFn == nil {
    84  		cfg.GetHashFn = func(n uint64) common.Hash {
    85  			return common.BytesToHash(crypto.Keccak256([]byte(new(big.Int).SetUint64(n).String())))
    86  		}
    87  	}
    88  }
    89  
    90  // Execute executes the code using the input as call data during the execution.
    91  // It returns the EVM's return value, the new state and an error if it failed.
    92  //
    93  // Executes sets up a in memory, temporarily, environment for the execution of
    94  // the given code. It makes sure that it's restored to it's original state afterwards.
    95  func Execute(code, input []byte, cfg *Config) ([]byte, *state.StateDB, error) {
    96  	if cfg == nil {
    97  		cfg = new(Config)
    98  	}
    99  	setDefaults(cfg)
   100  
   101  	if cfg.State == nil {
   102  		db, _ := ethdb.NewMemDatabase()
   103  		cfg.State, _ = state.New(common.Hash{}, state.NewDatabase(db))
   104  	}
   105  	var (
   106  		address = common.BytesToAddress([]byte("contract"))
   107  		vmenv   = NewEnv(cfg)
   108  		sender  = vm.AccountRef(cfg.Origin)
   109  	)
   110  	cfg.State.CreateAccount(address)
   111  	// set the receiver's (the executing contract) code for execution.
   112  	cfg.State.SetCode(address, code)
   113  	// Call the code with the given configuration.
   114  	ret, _, err := vmenv.Call(
   115  		sender,
   116  		common.BytesToAddress([]byte("contract")),
   117  		input,
   118  		cfg.GasLimit,
   119  		cfg.Value,
   120  	)
   121  
   122  	return ret, cfg.State, err
   123  }
   124  
   125  // Create executes the code using the EVM create method
   126  func Create(input []byte, cfg *Config) ([]byte, common.Address, uint64, error) {
   127  	if cfg == nil {
   128  		cfg = new(Config)
   129  	}
   130  	setDefaults(cfg)
   131  
   132  	if cfg.State == nil {
   133  		db, _ := ethdb.NewMemDatabase()
   134  		cfg.State, _ = state.New(common.Hash{}, state.NewDatabase(db))
   135  	}
   136  	var (
   137  		vmenv  = NewEnv(cfg)
   138  		sender = vm.AccountRef(cfg.Origin)
   139  	)
   140  
   141  	// Call the code with the given configuration.
   142  	code, address, leftOverGas, err := vmenv.Create(
   143  		sender,
   144  		input,
   145  		cfg.GasLimit,
   146  		cfg.Value,
   147  	)
   148  	return code, address, leftOverGas, err
   149  }
   150  
   151  // Call executes the code given by the contract's address. It will return the
   152  // EVM's return value or an error if it failed.
   153  //
   154  // Call, unlike Execute, requires a config and also requires the State field to
   155  // be set.
   156  func Call(address common.Address, input []byte, cfg *Config) ([]byte, uint64, error) {
   157  	setDefaults(cfg)
   158  
   159  	vmenv := NewEnv(cfg)
   160  
   161  	sender := cfg.State.GetOrNewStateObject(cfg.Origin)
   162  	// Call the code with the given configuration.
   163  	ret, leftOverGas, err := vmenv.Call(
   164  		sender,
   165  		address,
   166  		input,
   167  		cfg.GasLimit,
   168  		cfg.Value,
   169  	)
   170  
   171  	return ret, leftOverGas, err
   172  }