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, scriptSize *big.Int) *big.Int {
    totalGas := new(big.Int)
    totalGas.Add(totalGas, GasCreate)

    txTotalBytes := new(big.Int).Add(initSize, scriptSize)
    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

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

    for {
        // 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)
        useGas := func(amount *big.Int) {
            gas.Add(gas, amount)
        }

        switch op {
        case oSHA3:
            useGas(GasSha)
        case oSLOAD:
            useGas(GasSLoad)
        case oSSTORE:
            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
            }
            useGas(new(big.Int).Mul(mult, GasSStore))
        case oBALANCE:
            useGas(GasBalance)
        case oCREATE:
            require(3)

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

            useGas(CalculateTxGas(initSize, ethutil.Big0))
        case oCALL:
            useGas(GasCall)
        case oMLOAD, oMSIZE, oMSTORE8, oMSTORE:
            useGas(GasMemory)
        default:
            useGas(GasStep)
        }

        if closure.Gas.Cmp(gas) < 0 {
            ethutil.Config.Log.Debugln("Insufficient gas", closure.Gas, gas)

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

        // Sub the amount of gas from the remaining
        closure.Gas.Sub(closure.Gas, gas)

        switch op {
        case oLOG:
            stack.Print()
            mem.Print()
            // 0x20 range
        case oADD:
            require(2)
            x, y := stack.Popn()
            // (x + y) % 2 ** 256
            base.Add(x, y)
            // Pop result back on the stack
            stack.Push(base)
        case oSUB:
            require(2)
            x, y := stack.Popn()
            // (x - y) % 2 ** 256
            base.Sub(x, y)
            // Pop result back on the stack
            stack.Push(base)
        case oMUL:
            require(2)
            x, y := stack.Popn()
            // (x * y) % 2 ** 256
            base.Mul(x, y)
            // Pop result back on the stack
            stack.Push(base)
        case oDIV:
            require(2)
            x, y := stack.Popn()
            // floor(x / y)
            base.Div(x, y)
            // Pop result back on the stack
            stack.Push(base)
        case oSDIV:
            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 oMOD:
            require(2)
            x, y := stack.Popn()
            base.Mod(x, y)
            stack.Push(base)
        case oSMOD:
            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 oEXP:
            require(2)
            x, y := stack.Popn()
            base.Exp(x, y, Pow256)

            stack.Push(base)
        case oNEG:
            require(1)
            base.Sub(Pow256, stack.Pop())
            stack.Push(base)
        case oLT:
            require(2)
            x, y := stack.Popn()
            // x < y
            if x.Cmp(y) < 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }
        case oGT:
            require(2)
            x, y := stack.Popn()
            // x > y
            if x.Cmp(y) > 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }
        case oEQ:
            require(2)
            x, y := stack.Popn()
            // x == y
            if x.Cmp(y) == 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }
        case oNOT:
            require(1)
            x := stack.Pop()
            if x.Cmp(ethutil.BigFalse) == 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }

            // 0x10 range
        case oAND:
            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 oOR:
            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 oXOR:
            require(2)
            x, y := stack.Popn()
            stack.Push(base.Xor(x, y))
        case oBYTE:
            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 oSHA3:
            require(2)
            size, offset := stack.Popn()
            data := mem.Get(offset.Int64(), size.Int64())

            stack.Push(ethutil.BigD(data))
            // 0x30 range
        case oADDRESS:
            stack.Push(ethutil.BigD(closure.Object().Address()))
        case oBALANCE:
            stack.Push(closure.object.Amount)
        case oORIGIN:
            stack.Push(ethutil.BigD(vm.vars.Origin))
        case oCALLER:
            stack.Push(ethutil.BigD(closure.Callee().Address()))
        case oCALLVALUE:
            stack.Push(vm.vars.Value)
        case oCALLDATALOAD:
            require(1)
            offset := stack.Pop().Int64()
            val := closure.Args[offset : offset+32]

            stack.Push(ethutil.BigD(val))
        case oCALLDATASIZE:
            stack.Push(big.NewInt(int64(len(closure.Args))))
        case oGASPRICE:
            stack.Push(closure.Price)

            // 0x40 range
        case oPREVHASH:
            stack.Push(ethutil.BigD(vm.vars.PrevHash))
        case oCOINBASE:
            stack.Push(ethutil.BigD(vm.vars.Coinbase))
        case oTIMESTAMP:
            stack.Push(big.NewInt(vm.vars.Time))
        case oNUMBER:
            stack.Push(big.NewInt(int64(vm.vars.BlockNumber)))
        case oDIFFICULTY:
            stack.Push(vm.vars.Diff)
        case oGASLIMIT:
            // TODO
            stack.Push(big.NewInt(0))

            // 0x50 range
        case oPUSH1, oPUSH2, oPUSH3, oPUSH4, oPUSH5, oPUSH6, oPUSH7, oPUSH8, oPUSH9, oPUSH10, oPUSH11, oPUSH12, oPUSH13, oPUSH14, oPUSH15, oPUSH16, oPUSH17, oPUSH18, oPUSH19, oPUSH20, oPUSH21, oPUSH22, oPUSH23, oPUSH24, oPUSH25, oPUSH26, oPUSH27, oPUSH28, oPUSH29, oPUSH30, oPUSH31, oPUSH32:
            a := big.NewInt(int64(op) - int64(oPUSH1) + 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++

        case oPOP:
            require(1)
            stack.Pop()
        case oDUP:
            require(1)
            stack.Push(stack.Peek())
        case oSWAP:
            require(2)
            x, y := stack.Popn()
            stack.Push(y)
            stack.Push(x)
        case oMLOAD:
            require(1)
            offset := stack.Pop()
            stack.Push(ethutil.BigD(mem.Get(offset.Int64(), 32)))
        case oMSTORE: // 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 oMSTORE8:
            require(2)
            val, mStart := stack.Popn()
            base.And(val, new(big.Int).SetInt64(0xff))
            mem.Set(mStart.Int64(), 32, ethutil.BigToBytes(base, 256))
        case oSLOAD:
            require(1)
            loc := stack.Pop()
            val := closure.GetMem(loc)
            //fmt.Println("get", val.BigInt(), "@", loc)
            stack.Push(val.BigInt())
        case oSSTORE:
            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 oJUMP:
            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 oJUMPI:
            require(2)
            cond, pos := stack.Popn()
            if cond.Cmp(ethutil.BigTrue) == 0 {
                pc = pos
                //pc.Sub(pc, ethutil.Big1)
                continue
            }
        case oPC:
            stack.Push(pc)
        case oMSIZE:
            stack.Push(big.NewInt(int64(mem.Len())))
            // 0x60 range
        case oCREATE:
            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.Gas.Sub(closure.Gas, gas)
            // Create the closure
            closure := NewClosure(closure.callee,
                closure.Object(),
                contract.initScript,
                vm.state,
                gas,
                closure.Price)
            // Call the closure and set the return value as
            // main script.
            closure.Script, err = closure.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 oCALL:
            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.Gas.Sub(closure.Gas, gas)

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

                // Create a new callable closure
                closure := NewClosure(closure.Object(), 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 oRETURN:
            require(2)
            size, offset := stack.Popn()
            ret := mem.Get(offset.Int64(), size.Int64())

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

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

            closure.object.state.Purge()

            fallthrough
        case oSTOP: // 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 {
            hook(step-1, op, mem, stack, closure.Object())
        }
    }
}