path: root/ethchain/vm.go

package ethchain

import (
    _ "bytes"
    "fmt"
    "github.com/ethereum/eth-go/ethutil"
    _ "github.com/obscuren/secp256k1-go"
    _ "math"
    "math/big"
)

var (
    GasStep    = big.NewInt(1)
    GasSha     = big.NewInt(20)
    GasSLoad   = big.NewInt(20)
    GasSStore  = big.NewInt(100)
    GasBalance = big.NewInt(20)
    GasCreate  = big.NewInt(100)
    GasCall    = big.NewInt(20)
    GasMemory  = big.NewInt(1)
    GasTx      = big.NewInt(500)
)

func CalculateTxGas(initSize *big.Int) *big.Int {
    totalGas := new(big.Int)

    txTotalBytes := new(big.Int).Set(initSize)
    txTotalBytes.Div(txTotalBytes, ethutil.Big32)
    totalGas.Add(totalGas, new(big.Int).Mul(txTotalBytes, GasSStore))

    return totalGas
}

type Vm struct {
    txPool *TxPool
    // Stack for processing contracts
    stack *Stack
    // non-persistent key/value memory storage
    mem map[string]*big.Int

    vars RuntimeVars

    state *State

    stateManager *StateManager
}

type RuntimeVars struct {
    Origin      []byte
    BlockNumber uint64
    PrevHash    []byte
    Coinbase    []byte
    Time        int64
    Diff        *big.Int
    TxData      []string
    Value       *big.Int
}

func NewVm(state *State, stateManager *StateManager, vars RuntimeVars) *Vm {
    return &Vm{vars: vars, state: state, stateManager: stateManager}
}

var Pow256 = ethutil.BigPow(2, 256)

var isRequireError = false

func (vm *Vm) RunClosure(closure *Closure, hook DebugHook) (ret []byte, err error) {
    // Recover from any require exception
    defer func() {
        if r := recover(); r != nil /*&& isRequireError*/ {
            ret = closure.Return(nil)
            err = fmt.Errorf("%v", r)
            fmt.Println("vm err", err)
        }
    }()

    ethutil.Config.Log.Debugf("[VM] Running closure %x\n", closure.object.Address())

    // Memory for the current closure
    mem := &Memory{}
    // New stack (should this be shared?)
    stack := NewStack()
    require := func(m int) {
        if stack.Len() < m {
            isRequireError = true
            panic(fmt.Sprintf("stack = %d, req = %d", stack.Len(), m))
        }
    }

    // Instruction pointer
    pc := big.NewInt(0)
    // Current step count
    step := 0
    prevStep := 0

    if ethutil.Config.Debug {
        ethutil.Config.Log.Debugf("#   op\n")
    }

    for {
        prevStep = step
        // The base for all big integer arithmetic
        base := new(big.Int)

        step++
        // Get the memory location of pc
        val := closure.Get(pc)
        // Get the opcode (it must be an opcode!)
        op := OpCode(val.Uint())
        if ethutil.Config.Debug {
            ethutil.Config.Log.Debugf("%-3d %-4s", pc, op.String())
        }

        gas := new(big.Int)
        setStepGasUsage := func(amount *big.Int) {
            gas.Add(gas, amount)
        }

        switch op {
        case SHA3:
            setStepGasUsage(GasSha)
        case SLOAD:
            setStepGasUsage(GasSLoad)
        case SSTORE:
            var mult *big.Int
            y, x := stack.Peekn()
            val := closure.GetMem(x)
            if val.IsEmpty() && len(y.Bytes()) > 0 {
                mult = ethutil.Big2
            } else if !val.IsEmpty() && len(y.Bytes()) == 0 {
                mult = ethutil.Big0
            } else {
                mult = ethutil.Big1
            }
            setStepGasUsage(new(big.Int).Mul(mult, GasSStore))
        case BALANCE:
            setStepGasUsage(GasBalance)
        case CREATE:
            require(3)

            args := stack.Get(big.NewInt(3))
            initSize := new(big.Int).Add(args[1], args[0])

            setStepGasUsage(CalculateTxGas(initSize))
        case CALL:
            setStepGasUsage(GasCall)
        case MLOAD, MSIZE, MSTORE8, MSTORE:
            setStepGasUsage(GasMemory)
        default:
            setStepGasUsage(GasStep)
        }

        if !closure.UseGas(gas) {
            ethutil.Config.Log.Debugln("Insufficient gas", closure.Gas, gas)

            return closure.Return(nil), fmt.Errorf("insufficient gas %v %v", closure.Gas, gas)
        }

        switch op {
        case LOG:
            stack.Print()
            mem.Print()
            // 0x20 range
        case ADD:
            require(2)
            x, y := stack.Popn()
            // (x + y) % 2 ** 256
            base.Add(x, y)
            // Pop result back on the stack
            stack.Push(base)
        case SUB:
            require(2)
            x, y := stack.Popn()
            // (x - y) % 2 ** 256
            base.Sub(x, y)
            // Pop result back on the stack
            stack.Push(base)
        case MUL:
            require(2)
            x, y := stack.Popn()
            // (x * y) % 2 ** 256
            base.Mul(x, y)
            // Pop result back on the stack
            stack.Push(base)
        case DIV:
            require(2)
            x, y := stack.Popn()
            // floor(x / y)
            base.Div(x, y)
            // Pop result back on the stack
            stack.Push(base)
        case SDIV:
            require(2)
            x, y := stack.Popn()
            // n > 2**255
            if x.Cmp(Pow256) > 0 {
                x.Sub(Pow256, x)
            }
            if y.Cmp(Pow256) > 0 {
                y.Sub(Pow256, y)
            }
            z := new(big.Int)
            z.Div(x, y)
            if z.Cmp(Pow256) > 0 {
                z.Sub(Pow256, z)
            }
            // Push result on to the stack
            stack.Push(z)
        case MOD:
            require(2)
            x, y := stack.Popn()
            base.Mod(x, y)
            stack.Push(base)
        case SMOD:
            require(2)
            x, y := stack.Popn()
            // n > 2**255
            if x.Cmp(Pow256) > 0 {
                x.Sub(Pow256, x)
            }
            if y.Cmp(Pow256) > 0 {
                y.Sub(Pow256, y)
            }
            z := new(big.Int)
            z.Mod(x, y)
            if z.Cmp(Pow256) > 0 {
                z.Sub(Pow256, z)
            }
            // Push result on to the stack
            stack.Push(z)
        case EXP:
            require(2)
            x, y := stack.Popn()
            base.Exp(x, y, Pow256)

            stack.Push(base)
        case NEG:
            require(1)
            base.Sub(Pow256, stack.Pop())
            stack.Push(base)
        case LT:
            require(2)
            x, y := stack.Popn()
            // x < y
            if x.Cmp(y) < 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }
        case GT:
            require(2)
            x, y := stack.Popn()
            // x > y
            if x.Cmp(y) > 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }
        case EQ:
            require(2)
            x, y := stack.Popn()
            // x == y
            if x.Cmp(y) == 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }
        case NOT:
            require(1)
            x := stack.Pop()
            if x.Cmp(ethutil.BigFalse) == 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }

            // 0x10 range
        case AND:
            require(2)
            x, y := stack.Popn()
            if (x.Cmp(ethutil.BigTrue) >= 0) && (y.Cmp(ethutil.BigTrue) >= 0) {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }

        case OR:
            require(2)
            x, y := stack.Popn()
            if (x.Cmp(ethutil.BigInt0) >= 0) || (y.Cmp(ethutil.BigInt0) >= 0) {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }
        case XOR:
            require(2)
            x, y := stack.Popn()
            stack.Push(base.Xor(x, y))
        case BYTE:
            require(2)
            val, th := stack.Popn()
            if th.Cmp(big.NewInt(32)) < 0 {
                stack.Push(big.NewInt(int64(len(val.Bytes())-1) - th.Int64()))
            } else {
                stack.Push(ethutil.BigFalse)
            }

            // 0x20 range
        case SHA3:
            require(2)
            size, offset := stack.Popn()
            data := ethutil.Sha3Bin(mem.Get(offset.Int64(), size.Int64()))

            stack.Push(ethutil.BigD(data))
            // 0x30 range
        case ADDRESS:
            stack.Push(ethutil.BigD(closure.Object().Address()))
        case BALANCE:
            stack.Push(closure.object.Amount)
        case ORIGIN:
            stack.Push(ethutil.BigD(vm.vars.Origin))
        case CALLER:
            stack.Push(ethutil.BigD(closure.Callee().Address()))
        case CALLVALUE:
            stack.Push(vm.vars.Value)
        case CALLDATALOAD:
            require(1)
            offset := stack.Pop().Int64()

            var data []byte
            if len(closure.Args) >= int(offset+32) {
                data = closure.Args[offset : offset+32]
            } else {
                data = []byte{0}
            }

            stack.Push(ethutil.BigD(data))
        case CALLDATASIZE:
            stack.Push(big.NewInt(int64(len(closure.Args))))
        case GASPRICE:
            stack.Push(closure.Price)

            // 0x40 range
        case PREVHASH:
            stack.Push(ethutil.BigD(vm.vars.PrevHash))
        case COINBASE:
            stack.Push(ethutil.BigD(vm.vars.Coinbase))
        case TIMESTAMP:
            stack.Push(big.NewInt(vm.vars.Time))
        case NUMBER:
            stack.Push(big.NewInt(int64(vm.vars.BlockNumber)))
        case DIFFICULTY:
            stack.Push(vm.vars.Diff)
        case GASLIMIT:
            // TODO
            stack.Push(big.NewInt(0))

            // 0x50 range
        case PUSH1, PUSH2, PUSH3, PUSH4, PUSH5, PUSH6, PUSH7, PUSH8, PUSH9, PUSH10, PUSH11, PUSH12, PUSH13, PUSH14, PUSH15, PUSH16, PUSH17, PUSH18, PUSH19, PUSH20, PUSH21, PUSH22, PUSH23, PUSH24, PUSH25, PUSH26, PUSH27, PUSH28, PUSH29, PUSH30, PUSH31, PUSH32:
            a := big.NewInt(int64(op) - int64(PUSH1) + 1)
            pc.Add(pc, ethutil.Big1)
            data := closure.Gets(pc, a)
            val := ethutil.BigD(data.Bytes())
            // Push value to stack
            stack.Push(val)
            pc.Add(pc, a.Sub(a, big.NewInt(1)))

            step += int(op) - int(PUSH1) + 1
        case POP:
            require(1)
            stack.Pop()
        case DUP:
            require(1)
            stack.Push(stack.Peek())
        case SWAP:
            require(2)
            x, y := stack.Popn()
            stack.Push(y)
            stack.Push(x)
        case MLOAD:
            require(1)
            offset := stack.Pop()
            stack.Push(ethutil.BigD(mem.Get(offset.Int64(), 32)))
        case MSTORE: // Store the value at stack top-1 in to memory at location stack top
            require(2)
            // Pop value of the stack
            val, mStart := stack.Popn()
            mem.Set(mStart.Int64(), 32, ethutil.BigToBytes(val, 256))
        case MSTORE8:
            require(2)
            val, mStart := stack.Popn()
            base.And(val, new(big.Int).SetInt64(0xff))
            mem.Set(mStart.Int64(), 32, ethutil.BigToBytes(base, 256))
        case SLOAD:
            require(1)
            loc := stack.Pop()
            val := closure.GetMem(loc)
            //fmt.Println("get", val.BigInt(), "@", loc)
            stack.Push(val.BigInt())
        case SSTORE:
            require(2)
            val, loc := stack.Popn()
            //fmt.Println("storing", val, "@", loc)
            closure.SetStorage(loc, ethutil.NewValue(val))

            // Add the change to manifest
            vm.state.manifest.AddStorageChange(closure.Object(), loc.Bytes(), val)
        case JUMP:
            require(1)
            pc = stack.Pop()
            // Reduce pc by one because of the increment that's at the end of this for loop
            //pc.Sub(pc, ethutil.Big1)
            continue
        case JUMPI:
            require(2)
            cond, pos := stack.Popn()
            if cond.Cmp(ethutil.BigTrue) == 0 {
                pc = pos
                //pc.Sub(pc, ethutil.Big1)
                continue
            }
        case PC:
            stack.Push(pc)
        case MSIZE:
            stack.Push(big.NewInt(int64(mem.Len())))
            // 0x60 range
        case CREATE:
            require(3)

            value := stack.Pop()
            size, offset := stack.Popn()

            // Snapshot the current stack so we are able to
            // revert back to it later.
            snapshot := vm.state.Snapshot()

            // Generate a new address
            addr := ethutil.CreateAddress(closure.callee.Address(), closure.callee.N())
            // Create a new contract
            contract := NewContract(addr, value, []byte(""))
            // Set the init script
            contract.initScript = mem.Get(offset.Int64(), size.Int64())
            // Transfer all remaining gas to the new
            // contract so it may run the init script
            gas := new(big.Int).Set(closure.Gas)
            closure.UseGas(gas)

            // Create the closure
            c := NewClosure(closure.callee,
                closure.Object(),
                contract.initScript,
                vm.state,
                gas,
                closure.Price)
            // Call the closure and set the return value as
            // main script.
            c.Script, gas, err = c.Call(vm, nil, hook)

            if err != nil {
                stack.Push(ethutil.BigFalse)

                // Revert the state as it was before.
                vm.state.Revert(snapshot)
            } else {
                stack.Push(ethutil.BigD(addr))

                vm.state.UpdateStateObject(contract)
            }
        case CALL:
            require(7)
            // Closure addr
            addr := stack.Pop()
            // Pop gas and value of the stack.
            gas, value := stack.Popn()
            // Pop input size and offset
            inSize, inOffset := stack.Popn()
            // Pop return size and offset
            retSize, retOffset := stack.Popn()
            // Make sure there's enough gas
            if closure.Gas.Cmp(gas) < 0 {
                stack.Push(ethutil.BigFalse)

                break
            }

            // Get the arguments from the memory
            args := mem.Get(inOffset.Int64(), inSize.Int64())

            snapshot := vm.state.Snapshot()

            // Fetch the contract which will serve as the closure body
            contract := vm.state.GetStateObject(addr.Bytes())

            if contract != nil {
                // Prepay for the gas
                // If gas is set to 0 use all remaining gas for the next call
                if gas.Cmp(big.NewInt(0)) == 0 {
                    // Copy
                    gas = new(big.Int).Set(closure.Gas)
                }
                closure.UseGas(gas)

                // Add the value to the state object
                contract.AddAmount(value)

                // Create a new callable closure
                closure := NewClosure(closure, contract, contract.script, vm.state, gas, closure.Price)
                // Executer the closure and get the return value (if any)
                ret, _, err := closure.Call(vm, args, hook)
                if err != nil {
                    stack.Push(ethutil.BigFalse)
                    // Reset the changes applied this object
                    vm.state.Revert(snapshot)
                } else {
                    stack.Push(ethutil.BigTrue)

                    vm.state.UpdateStateObject(contract)

                    mem.Set(retOffset.Int64(), retSize.Int64(), ret)
                }
            } else {
                ethutil.Config.Log.Debugf("Contract %x not found\n", addr.Bytes())
                stack.Push(ethutil.BigFalse)
            }
        case RETURN:
            require(2)
            size, offset := stack.Popn()
            ret := mem.Get(offset.Int64(), size.Int64())

            return closure.Return(ret), nil
        case SUICIDE:
            require(1)

            receiver := vm.state.GetAccount(stack.Pop().Bytes())
            receiver.AddAmount(closure.object.Amount)
            vm.state.UpdateStateObject(receiver)

            closure.object.state.Purge()

            fallthrough
        case STOP: // Stop the closure
            return closure.Return(nil), nil
        default:
            ethutil.Config.Log.Debugf("Invalid opcode %x\n", op)

            return closure.Return(nil), fmt.Errorf("Invalid opcode %x", op)
        }

        pc.Add(pc, ethutil.Big1)

        if hook != nil {
            if !hook(prevStep, op, mem, stack, closure.Object()) {
                return nil, nil
            }
        }
    }
}