package vm import ( gmath "math" "math/big" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/common/math" "github.com/ethereum/go-ethereum/params" ) // memoryGasCosts calculates the quadratic gas for memory expansion. It does so // only for the memory region that is expanded, not the total memory. func memoryGasCost(mem *Memory, newMemSize uint64) (uint64, error) { // The maximum that will fit in a uint64 is max_word_count - 1 // anything above that will result in an overflow. if newMemSize > gmath.MaxUint64-32 { return 0, errGasUintOverflow } if newMemSize == 0 { return 0, nil } newMemSizeWords := toWordSize(newMemSize) newMemSize = newMemSizeWords * 32 if newMemSize > uint64(mem.Len()) { square := newMemSizeWords * newMemSizeWords linCoef := newMemSizeWords * params.MemoryGas quadCoef := square / params.QuadCoeffDiv newTotalFee := linCoef + quadCoef fee := newTotalFee - mem.lastGasCost mem.lastGasCost = newTotalFee return fee, nil } return 0, nil } func constGasFunc(gas uint64) gasFunc { return func(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { return gas, nil } } func gasCalldataCopy(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, err } var overflow bool if gas, overflow = math.SafeAdd(gas, GasFastestStep); overflow { return 0, errGasUintOverflow } words, overflow := bigUint64(stack.Back(2)) if overflow { return 0, errGasUintOverflow } if words, overflow = math.SafeMul(toWordSize(words), params.CopyGas); overflow { return 0, errGasUintOverflow } if gas, overflow = math.SafeAdd(gas, words); overflow { return 0, errGasUintOverflow } return gas, nil } func gasSStore(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { var ( y, x = stack.Back(1), stack.Back(0) val = evm.StateDB.GetState(contract.Address(), common.BigToHash(x)) ) // This checks for 3 scenario's and calculates gas accordingly // 1. From a zero-value address to a non-zero value (NEW VALUE) // 2. From a non-zero value address to a zero-value address (DELETE) // 3. From a non-zero to a non-zero (CHANGE) if common.EmptyHash(val) && !common.EmptyHash(common.BigToHash(y)) { // 0 => non 0 return params.SstoreSetGas, nil } else if !common.EmptyHash(val) && common.EmptyHash(common.BigToHash(y)) { evm.StateDB.AddRefund(new(big.Int).SetUint64(params.SstoreRefundGas)) return params.SstoreClearGas, nil } else { // non 0 => non 0 (or 0 => 0) return params.SstoreResetGas, nil } } func makeGasLog(n uint64) gasFunc { return func(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { requestedSize, overflow := bigUint64(stack.Back(1)) if overflow { return 0, errGasUintOverflow } gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, err } if gas, overflow = math.SafeAdd(gas, params.LogGas); overflow { return 0, errGasUintOverflow } if gas, overflow = math.SafeAdd(gas, n*params.LogTopicGas); overflow { return 0, errGasUintOverflow } var memorySizeGas uint64 if memorySizeGas, overflow = math.SafeMul(requestedSize, params.LogDataGas); overflow { return 0, errGasUintOverflow } if gas, overflow = math.SafeAdd(gas, memorySizeGas); overflow { return 0, errGasUintOverflow } return gas, nil } } func gasSha3(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { var overflow bool gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, err } if gas, overflow = math.SafeAdd(gas, params.Sha3Gas); overflow { return 0, errGasUintOverflow } wordGas, overflow := bigUint64(stack.Back(1)) if overflow { return 0, errGasUintOverflow } if wordGas, overflow = math.SafeMul(toWordSize(wordGas), params.Sha3WordGas); overflow { return 0, errGasUintOverflow } if gas, overflow = math.SafeAdd(gas, wordGas); overflow { return 0, errGasUintOverflow } return gas, nil } func gasCodeCopy(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, err } var overflow bool if gas, overflow = math.SafeAdd(gas, GasFastestStep); overflow { return 0, errGasUintOverflow } wordGas, overflow := bigUint64(stack.Back(2)) if overflow { return 0, errGasUintOverflow } if wordGas, overflow = math.SafeMul(toWordSize(wordGas), params.CopyGas); overflow { return 0, errGasUintOverflow } if gas, overflow = math.SafeAdd(gas, wordGas); overflow { return 0, errGasUintOverflow } return gas, nil } func gasExtCodeCopy(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, err } var overflow bool if gas, overflow = math.SafeAdd(gas, gt.ExtcodeCopy); overflow { return 0, errGasUintOverflow } wordGas, overflow := bigUint64(stack.Back(3)) if overflow { return 0, errGasUintOverflow } if wordGas, overflow = math.SafeMul(toWordSize(wordGas), params.CopyGas); overflow { return 0, errGasUintOverflow } if gas, overflow = math.SafeAdd(gas, wordGas); overflow { return 0, errGasUintOverflow } return gas, nil } func gasMLoad(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { var overflow bool gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, errGasUintOverflow } if gas, overflow = math.SafeAdd(gas, GasFastestStep); overflow { return 0, errGasUintOverflow } return gas, nil } func gasMStore8(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { var overflow bool gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, errGasUintOverflow } if gas, overflow = math.SafeAdd(gas, GasFastestStep); overflow { return 0, errGasUintOverflow } return gas, nil } func gasMStore(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { var overflow bool gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, errGasUintOverflow } if gas, overflow = math.SafeAdd(gas, GasFastestStep); overflow { return 0, errGasUintOverflow } return gas, nil } func gasCreate(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { var overflow bool gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, err } if gas, overflow = math.SafeAdd(gas, params.CreateGas); overflow { return 0, errGasUintOverflow } return gas, nil } func gasBalance(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { return gt.Balance, nil } func gasExtCodeSize(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { return gt.ExtcodeSize, nil } func gasSLoad(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { return gt.SLoad, nil } func gasExp(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { expByteLen := uint64((stack.data[stack.len()-2].BitLen() + 7) / 8) var ( gas = expByteLen * gt.ExpByte // no overflow check required. Max is 256 * ExpByte gas overflow bool ) if gas, overflow = math.SafeAdd(gas, GasSlowStep); overflow { return 0, errGasUintOverflow } return gas, nil } func gasCall(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { var ( gas = gt.Calls transfersValue = stack.Back(2).BitLen() > 0 address = common.BigToAddress(stack.Back(1)) eip158 = evm.ChainConfig().IsEIP158(evm.BlockNumber) ) if eip158 { if evm.StateDB.Empty(address) && transfersValue { gas += params.CallNewAccountGas } } else if !evm.StateDB.Exist(address) { gas += params.CallNewAccountGas } if transfersValue { gas += params.CallValueTransferGas } memoryGas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, err } var overflow bool if gas, overflow = math.SafeAdd(gas, memoryGas); overflow { return 0, errGasUintOverflow } cg, err := callGas(gt, contract.Gas, gas, stack.Back(0)) if err != nil { return 0, err } // Replace the stack item with the new gas calculation. This means that // either the original item is left on the stack or the item is replaced by: // (availableGas - gas) * 63 / 64 // We replace the stack item so that it's available when the opCall instruction is // called. This information is otherwise lost due to the dependency on *current* // available gas. stack.data[stack.len()-1] = new(big.Int).SetUint64(cg) if gas, overflow = math.SafeAdd(gas, cg); overflow { return 0, errGasUintOverflow } return gas, nil } func gasCallCode(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { gas := gt.Calls if stack.Back(2).BitLen() > 0 { gas += params.CallValueTransferGas } memoryGas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, err } var overflow bool if gas, overflow = math.SafeAdd(gas, memoryGas); overflow { return 0, errGasUintOverflow } cg, err := callGas(gt, contract.Gas, gas, stack.Back(0)) if err != nil { return 0, err } // Replace the stack item with the new gas calculation. This means that // either the original item is left on the stack or the item is replaced by: // (availableGas - gas) * 63 / 64 // We replace the stack item so that it's available when the opCall instruction is // called. This information is otherwise lost due to the dependency on *current* // available gas. stack.data[stack.len()-1] = new(big.Int).SetUint64(cg) if gas, overflow = math.SafeAdd(gas, cg); overflow { return 0, errGasUintOverflow } return gas, nil } func gasReturn(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { return memoryGasCost(mem, memorySize) } func gasSuicide(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { var gas uint64 // EIP150 homestead gas reprice fork: if evm.ChainConfig().IsEIP150(evm.BlockNumber) { gas = gt.Suicide var ( address = common.BigToAddress(stack.Back(0)) eip158 = evm.ChainConfig().IsEIP158(evm.BlockNumber) ) if eip158 { // if empty and transfers value if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).BitLen() > 0 { gas += gt.CreateBySuicide } } else if !evm.StateDB.Exist(address) { gas += gt.CreateBySuicide } } if !evm.StateDB.HasSuicided(contract.Address()) { evm.StateDB.AddRefund(new(big.Int).SetUint64(params.SuicideRefundGas)) } return gas, nil } func gasDelegateCall(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { gas, err := memoryGasCost(mem, memorySize) if err != nil { return 0, err } var overflow bool if gas, overflow = math.SafeAdd(gas, gt.Calls); overflow { return 0, errGasUintOverflow } cg, err := callGas(gt, contract.Gas, gas, stack.Back(0)) if err != nil { return 0, err } // Replace the stack item with the new gas calculation. This means that // either the original item is left on the stack or the item is replaced by: // (availableGas - gas) * 63 / 64 // We replace the stack item so that it's available when the opCall instruction is // called. stack.data[stack.len()-1] = new(big.Int).SetUint64(cg) if gas, overflow = math.SafeAdd(gas, cg); overflow { return 0, errGasUintOverflow } return gas, nil } func gasPush(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { return GasFastestStep, nil } func gasSwap(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { return GasFastestStep, nil } func gasDup(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { return GasFastestStep, nil }