path: root/ethchain/vm.go

package ethchain

import (
    "fmt"
    "github.com/ethereum/eth-go/ethutil"
    "github.com/ethereum/eth-go/ethlog"
    "math"
    "math/big"
)

var vmlogger = ethlog.NewLogger("VM")

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)
    GasData    = big.NewInt(5)
    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

    Verbose bool

    logStr string

    err error
}

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

func (self *Vm) Printf(format string, v ...interface{}) *Vm {
    if self.Verbose {
        self.logStr += fmt.Sprintf(format, v...)
    }

    return self
}

func (self *Vm) Endl() *Vm {
    if self.Verbose {
        vmlogger.Infoln(self.logStr)
        self.logStr = ""
    }

    return self
}

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 {
            ret = closure.Return(nil)
            err = fmt.Errorf("%v", r)
            vmlogger.Errorln("vm err", err)
        }
    }()

    vmlogger.Debugf("(~) %x gas: %v (d) %x\n", closure.object.Address(), closure.Gas, closure.Args)

    // 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

    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())

        gas := new(big.Int)
        addStepGasUsage := func(amount *big.Int) {
            if amount.Cmp(ethutil.Big0) >= 0 {
                gas.Add(gas, amount)
            }
        }

        addStepGasUsage(GasStep)

        var newMemSize uint64 = 0
        switch op {
        case STOP:
            gas.Set(ethutil.Big0)
        case SUICIDE:
            gas.Set(ethutil.Big0)
        case SLOAD:
            gas.Set(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
            }
            gas = new(big.Int).Mul(mult, GasSStore)
        case BALANCE:
            gas.Set(GasBalance)
        case MSTORE:
            require(2)
            newMemSize = stack.Peek().Uint64() + 32
        case MLOAD:

        case MSTORE8:
            require(2)
            newMemSize = stack.Peek().Uint64() + 1
        case RETURN:
            require(2)

            newMemSize = stack.Peek().Uint64() + stack.data[stack.Len()-2].Uint64()
        case SHA3:
            require(2)

            gas.Set(GasSha)

            newMemSize = stack.Peek().Uint64() + stack.data[stack.Len()-2].Uint64()
        case CALLDATACOPY:
            require(3)

            newMemSize = stack.Peek().Uint64() + stack.data[stack.Len()-3].Uint64()
        case CODECOPY:
            require(3)

            newMemSize = stack.Peek().Uint64() + stack.data[stack.Len()-3].Uint64()
        case CALL:
            require(7)
            gas.Set(GasCall)
            addStepGasUsage(stack.data[stack.Len()-1])

            x := stack.data[stack.Len()-6].Uint64() + stack.data[stack.Len()-7].Uint64()
            y := stack.data[stack.Len()-4].Uint64() + stack.data[stack.Len()-5].Uint64()

            newMemSize = uint64(math.Max(float64(x), float64(y)))
        case CREATE:
            require(3)
            gas.Set(GasCreate)

            newMemSize = stack.data[stack.Len()-2].Uint64() + stack.data[stack.Len()-3].Uint64()
        }

        newMemSize = (newMemSize + 31) / 32 * 32
        if newMemSize > uint64(mem.Len()) {
            m := GasMemory.Uint64() * (newMemSize - uint64(mem.Len())) / 32
            addStepGasUsage(big.NewInt(int64(m)))
        }

        if !closure.UseGas(gas) {
            err := fmt.Errorf("Insufficient gas for %v. req %v has %v", op, gas, closure.Gas)

            closure.UseGas(closure.Gas)

            return closure.Return(nil), err
        }

        vm.Printf("(pc) %-3d -o- %-14s", pc, op.String())
        vm.Printf(" (g) %-3v (%v)", gas, closure.Gas)

        mem.Resize(newMemSize)

        switch op {
        case LOG:
            stack.Print()
            mem.Print()
            // 0x20 range
        case ADD:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v + %v", y, x)

            base.Add(y, x)

            vm.Printf(" = %v", base)
            // Pop result back on the stack
            stack.Push(base)
        case SUB:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v - %v", y, x)

            base.Sub(y, x)

            vm.Printf(" = %v", base)
            // Pop result back on the stack
            stack.Push(base)
        case MUL:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v * %v", y, x)

            base.Mul(y, x)

            vm.Printf(" = %v", base)
            // Pop result back on the stack
            stack.Push(base)
        case DIV:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v / %v", y, x)

            base.Div(y, x)

            vm.Printf(" = %v", base)
            // 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()

            vm.Printf(" %v %% %v", y, x)

            base.Mod(y, x)

            vm.Printf(" = %v", base)
            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()

            vm.Printf(" %v ** %v", y, x)

            base.Exp(y, x, Pow256)

            vm.Printf(" = %v", base)

            stack.Push(base)
        case NEG:
            require(1)
            base.Sub(Pow256, stack.Pop())
            stack.Push(base)
        case LT:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v < %v", y, x)
            // x < y
            if y.Cmp(x) < 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }
        case GT:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v > %v", y, x)

            // x > y
            if y.Cmp(x) > 0 {
                stack.Push(ethutil.BigTrue)
            } else {
                stack.Push(ethutil.BigFalse)
            }
        case EQ:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v == %v", y, x)

            // 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.BigFalse)
            } else {
                stack.Push(ethutil.BigTrue)
            }

            // 0x10 range
        case AND:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v & %v", y, x)

            stack.Push(base.And(y, x))
        case OR:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v | %v", y, x)

            stack.Push(base.Or(y, x))
        case XOR:
            require(2)
            x, y := stack.Popn()
            vm.Printf(" %v ^ %v", y, x)

            stack.Push(base.Xor(y, x))
        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:
            caller := closure.caller.Address()
            stack.Push(ethutil.BigD(caller))

            vm.Printf(" => %x", caller)
        case CALLVALUE:
            stack.Push(vm.vars.Value)
        case CALLDATALOAD:
            require(1)
            offset := stack.Pop().Int64()

            data := make([]byte, 32)
            if len(closure.Args) >= int(offset) {
                l := int64(math.Min(float64(offset+32), float64(len(closure.Args))))

                copy(data, closure.Args[offset:l])
            }

            vm.Printf(" => 0x%x", data)

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

            vm.Printf(" => %d", l)
        case CALLDATACOPY:
            var (
                size = int64(len(closure.Args))
                mOff = stack.Pop().Int64()
                cOff = stack.Pop().Int64()
                l    = stack.Pop().Int64()
            )

            if cOff > size {
                cOff = 0
                l = 0
            } else if cOff+l > size {
                l = 0
            }

            code := closure.Args[cOff : cOff+l]

            mem.Set(mOff, l, code)
        case CODESIZE:
            l := big.NewInt(int64(len(closure.Script)))
            stack.Push(l)

            vm.Printf(" => %d", l)
        case CODECOPY:
            var (
                size = int64(len(closure.Script))
                mOff = stack.Pop().Int64()
                cOff = stack.Pop().Int64()
                l    = stack.Pop().Int64()
            )

            if cOff > size {
                cOff = 0
                l = 0
            } else if cOff+l > size {
                l = 0
            }

            code := closure.Script[cOff : cOff+l]

            mem.Set(mOff, l, code)
        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(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

            vm.Printf(" => 0x%x", data.Bytes())
        case POP:
            require(1)
            stack.Pop()
        case DUP:
            require(1)
            stack.Push(stack.Peek())

            vm.Printf(" => 0x%x", stack.Peek().Bytes())
        case SWAP:
            require(2)
            x, y := stack.Popn()
            stack.Push(y)
            stack.Push(x)
        case MLOAD:
            require(1)
            offset := stack.Pop()
            val := ethutil.BigD(mem.Get(offset.Int64(), 32))
            stack.Push(val)

            vm.Printf(" => 0x%x", val.Bytes())
        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))

            vm.Printf(" => 0x%x", val)
        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))

            vm.Printf(" => 0x%x", val)
        case SLOAD:
            require(1)
            loc := stack.Pop()
            val := closure.GetMem(loc)

            stack.Push(val.BigInt())

            vm.Printf(" {0x%x} 0x%x", loc.Bytes(), val.Bytes())
        case SSTORE:
            require(2)
            val, loc := stack.Popn()
            closure.SetStorage(loc, ethutil.NewValue(val))

            // Add the change to manifest
            vm.state.manifest.AddStorageChange(closure.Object(), loc.Bytes(), val)

            vm.Printf(" {0x%x} 0x%x", loc, 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
            vm.Printf(" ~> %v", pc).Endl()

            continue
        case JUMPI:
            require(2)
            cond, pos := stack.Popn()
            if cond.Cmp(ethutil.BigTrue) >= 0 {
                pc = pos

                vm.Printf(" ~> %v (t)", pc).Endl()

                continue
            } else {
                vm.Printf(" (f)")
            }
        case PC:
            stack.Push(pc)
        case MSIZE:
            stack.Push(big.NewInt(int64(mem.Len())))
        case GAS:
            stack.Push(closure.Gas)
            // 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.Copy()

            // Generate a new address
            addr := ethutil.CreateAddress(closure.caller.Address(), closure.caller.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.caller,
                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.Set(snapshot)
            } else {
                stack.Push(ethutil.BigD(addr))
            }
        case CALL:
            require(7)

            vm.Endl()

            gas := stack.Pop()
            // Pop gas and value of the stack.
            value, addr := stack.Popn()
            // Pop input size and offset
            inSize, inOffset := stack.Popn()
            // Pop return size and offset
            retSize, retOffset := stack.Popn()

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

            if closure.object.Amount.Cmp(value) < 0 {
                vmlogger.Debugf("Insufficient funds to transfer value. Req %v, has %v", value, closure.object.Amount)

                stack.Push(ethutil.BigFalse)
            } else {
                snapshot := vm.state.Copy()

                stateObject := vm.state.GetOrNewStateObject(addr.Bytes())

                closure.object.SubAmount(value)
                // Add the value to the state object
                stateObject.AddAmount(value)

                // Create a new callable closure
                closure := NewClosure(closure, stateObject, stateObject.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)

                    vmlogger.Debugf("Closure execution failed. %v\n", err)

                    vm.err = err
                    vm.state.Set(snapshot)
                } else {
                    stack.Push(ethutil.BigTrue)

                    mem.Set(retOffset.Int64(), retSize.Int64(), ret)
                }
            }
        case RETURN:
            require(2)
            size, offset := stack.Popn()
            ret := mem.Get(offset.Int64(), size.Int64())

            vm.Printf(" => (%d) 0x%x", len(ret), ret).Endl()

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

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

            trie := closure.object.state.trie
            trie.NewIterator().Each(func(key string, v *ethutil.Value) {
                trie.Delete(key)
            })

            fallthrough
        case STOP: // Stop the closure
            vm.Endl()

            return closure.Return(nil), nil
        default:
            vmlogger.Debugf("Invalid opcode %x\n", op)

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

        pc.Add(pc, ethutil.Big1)

        vm.Endl()

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