path: root/ethchain/vm.go

package ethchain

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

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

    vars RuntimeVars
}

type RuntimeVars struct {
    address     []byte
    blockNumber uint64
    sender      []byte
    prevHash    []byte
    coinbase    []byte
    time        int64
    diff        *big.Int
    txValue     *big.Int
    txData      []string
}

func (vm *Vm) Process(contract *Contract, state *State, vars RuntimeVars) {
    vm.mem = make(map[string]*big.Int)
    vm.stack = NewStack()

    addr := vars.address // tx.Hash()[12:]
    // Instruction pointer
    pc := 0

    if contract == nil {
        fmt.Println("Contract not found")
        return
    }

    Pow256 := ethutil.BigPow(2, 256)

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

    stepcount := 0
    totalFee := new(big.Int)

out:
    for {
        stepcount++
        // The base big int for all calculations. Use this for any results.
        base := new(big.Int)
        val := contract.GetMem(pc)
        //fmt.Printf("%x = %d, %v %x\n", r, len(r), v, nb)
        op := OpCode(val.Uint())

        var fee *big.Int = new(big.Int)
        var fee2 *big.Int = new(big.Int)
        if stepcount > 16 {
            fee.Add(fee, StepFee)
        }

        // Calculate the fees
        switch op {
        case oSSTORE:
            y, x := vm.stack.Peekn()
            val := contract.Addr(ethutil.BigToBytes(x, 256))
            if val.IsEmpty() && len(y.Bytes()) > 0 {
                fee2.Add(DataFee, StoreFee)
            } else {
                fee2.Sub(DataFee, StoreFee)
            }
        case oSLOAD:
            fee.Add(fee, StoreFee)
        case oEXTRO, oBALANCE:
            fee.Add(fee, ExtroFee)
        case oSHA256, oRIPEMD160, oECMUL, oECADD, oECSIGN, oECRECOVER, oECVALID:
            fee.Add(fee, CryptoFee)
        case oMKTX:
            fee.Add(fee, ContractFee)
        }

        tf := new(big.Int).Add(fee, fee2)
        if contract.Amount.Cmp(tf) < 0 {
            fmt.Println("Insufficient fees to continue running the contract", tf, contract.Amount)
            break
        }
        // Add the fee to the total fee. It's subtracted when we're done looping
        totalFee.Add(totalFee, tf)

        if ethutil.Config.Debug {
            ethutil.Config.Log.Debugf("%-3d %-4s", pc, op.String())
        }

        switch op {
        case oSTOP:
            fmt.Println("")
            break out
        case oADD:
            x, y := vm.stack.Popn()
            // (x + y) % 2 ** 256
            base.Add(x, y)
            base.Mod(base, Pow256)
            // Pop result back on the stack
            vm.stack.Push(base)
        case oSUB:
            x, y := vm.stack.Popn()
            // (x - y) % 2 ** 256
            base.Sub(x, y)
            base.Mod(base, Pow256)
            // Pop result back on the stack
            vm.stack.Push(base)
        case oMUL:
            x, y := vm.stack.Popn()
            // (x * y) % 2 ** 256
            base.Mul(x, y)
            base.Mod(base, Pow256)
            // Pop result back on the stack
            vm.stack.Push(base)
        case oDIV:
            x, y := vm.stack.Popn()
            // floor(x / y)
            base.Div(x, y)
            // Pop result back on the stack
            vm.stack.Push(base)
        case oSDIV:
            x, y := vm.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
            vm.stack.Push(z)
        case oMOD:
            x, y := vm.stack.Popn()
            base.Mod(x, y)
            vm.stack.Push(base)
        case oSMOD:
            x, y := vm.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
            vm.stack.Push(z)
        case oEXP:
            x, y := vm.stack.Popn()
            base.Exp(x, y, Pow256)

            vm.stack.Push(base)
        case oNEG:
            base.Sub(Pow256, vm.stack.Pop())
            vm.stack.Push(base)
        case oLT:
            x, y := vm.stack.Popn()
            // x < y
            if x.Cmp(y) < 0 {
                vm.stack.Push(ethutil.BigTrue)
            } else {
                vm.stack.Push(ethutil.BigFalse)
            }
        case oLE:
            x, y := vm.stack.Popn()
            // x <= y
            if x.Cmp(y) < 1 {
                vm.stack.Push(ethutil.BigTrue)
            } else {
                vm.stack.Push(ethutil.BigFalse)
            }
        case oGT:
            x, y := vm.stack.Popn()
            // x > y
            if x.Cmp(y) > 0 {
                vm.stack.Push(ethutil.BigTrue)
            } else {
                vm.stack.Push(ethutil.BigFalse)
            }
        case oGE:
            x, y := vm.stack.Popn()
            // x >= y
            if x.Cmp(y) > -1 {
                vm.stack.Push(ethutil.BigTrue)
            } else {
                vm.stack.Push(ethutil.BigFalse)
            }
        case oNOT:
            x, y := vm.stack.Popn()
            // x != y
            if x.Cmp(y) != 0 {
                vm.stack.Push(ethutil.BigTrue)
            } else {
                vm.stack.Push(ethutil.BigFalse)
            }
        case oMYADDRESS:
            vm.stack.Push(ethutil.BigD(addr))
        case oTXSENDER:
            vm.stack.Push(ethutil.BigD(vars.sender))
        case oTXVALUE:
            vm.stack.Push(vars.txValue)
        case oTXDATAN:
            vm.stack.Push(big.NewInt(int64(len(vars.txData))))
        case oTXDATA:
            v := vm.stack.Pop()
            // v >= len(data)
            if v.Cmp(big.NewInt(int64(len(vars.txData)))) >= 0 {
                vm.stack.Push(ethutil.Big("0"))
            } else {
                vm.stack.Push(ethutil.Big(vars.txData[v.Uint64()]))
            }
        case oBLK_PREVHASH:
            vm.stack.Push(ethutil.BigD(vars.prevHash))
        case oBLK_COINBASE:
            vm.stack.Push(ethutil.BigD(vars.coinbase))
        case oBLK_TIMESTAMP:
            vm.stack.Push(big.NewInt(vars.time))
        case oBLK_NUMBER:
            vm.stack.Push(big.NewInt(int64(vars.blockNumber)))
        case oBLK_DIFFICULTY:
            vm.stack.Push(vars.diff)
        case oBASEFEE:
            // e = 10^21
            e := big.NewInt(0).Exp(big.NewInt(10), big.NewInt(21), big.NewInt(0))
            d := new(big.Rat)
            d.SetInt(vars.diff)
            c := new(big.Rat)
            c.SetFloat64(0.5)
            // d = diff / 0.5
            d.Quo(d, c)
            // base = floor(d)
            base.Div(d.Num(), d.Denom())

            x := new(big.Int)
            x.Div(e, base)

            // x = floor(10^21 / floor(diff^0.5))
            vm.stack.Push(x)
        case oSHA256, oSHA3, oRIPEMD160:
            // This is probably save
            // ceil(pop / 32)
            length := int(math.Ceil(float64(vm.stack.Pop().Uint64()) / 32.0))
            // New buffer which will contain the concatenated popped items
            data := new(bytes.Buffer)
            for i := 0; i < length; i++ {
                // Encode the number to bytes and have it 32bytes long
                num := ethutil.NumberToBytes(vm.stack.Pop().Bytes(), 256)
                data.WriteString(string(num))
            }

            if op == oSHA256 {
                vm.stack.Push(base.SetBytes(ethutil.Sha256Bin(data.Bytes())))
            } else if op == oSHA3 {
                vm.stack.Push(base.SetBytes(ethutil.Sha3Bin(data.Bytes())))
            } else {
                vm.stack.Push(base.SetBytes(ethutil.Ripemd160(data.Bytes())))
            }
        case oECMUL:
            y := vm.stack.Pop()
            x := vm.stack.Pop()
            //n := vm.stack.Pop()

            //if ethutil.Big(x).Cmp(ethutil.Big(y)) {
            data := new(bytes.Buffer)
            data.WriteString(x.String())
            data.WriteString(y.String())
            if secp256k1.VerifyPubkeyValidity(data.Bytes()) == 1 {
                // TODO
            } else {
                // Invalid, push infinity
                vm.stack.Push(ethutil.Big("0"))
                vm.stack.Push(ethutil.Big("0"))
            }
            //} else {
            //  // Invalid, push infinity
            //  vm.stack.Push("0")
            //  vm.stack.Push("0")
            //}

        case oECADD:
        case oECSIGN:
        case oECRECOVER:
        case oECVALID:
        case oPUSH:
            pc++
            vm.stack.Push(contract.GetMem(pc).BigInt())
        case oPOP:
            // Pop current value of the stack
            vm.stack.Pop()
        case oDUP:
            // Dup top stack
            x := vm.stack.Pop()
            vm.stack.Push(x)
            vm.stack.Push(x)
        case oSWAP:
            // Swap two top most values
            x, y := vm.stack.Popn()
            vm.stack.Push(y)
            vm.stack.Push(x)
        case oMLOAD:
            x := vm.stack.Pop()
            vm.stack.Push(vm.mem[x.String()])
        case oMSTORE:
            x, y := vm.stack.Popn()
            vm.mem[x.String()] = y
        case oSLOAD:
            // Load the value in storage and push it on the stack
            x := vm.stack.Pop()
            // decode the object as a big integer
            decoder := contract.Addr(x.Bytes())
            if !decoder.IsNil() {
                vm.stack.Push(decoder.BigInt())
            } else {
                vm.stack.Push(ethutil.BigFalse)
            }
        case oSSTORE:
            // Store Y at index X
            y, x := vm.stack.Popn()
            addr := ethutil.BigToBytes(x, 256)
            fmt.Printf(" => %x (%v) @ %v", y.Bytes(), y, ethutil.BigD(addr))
            contract.SetAddr(addr, y)
            //contract.State().Update(string(idx), string(y))
        case oJMP:
            x := int(vm.stack.Pop().Uint64())
            // Set pc to x - 1 (minus one so the incrementing at the end won't effect it)
            pc = x
            pc--
        case oJMPI:
            x := vm.stack.Pop()
            // Set pc to x if it's non zero
            if x.Cmp(ethutil.BigFalse) != 0 {
                pc = int(x.Uint64())
                pc--
            }
        case oIND:
            vm.stack.Push(big.NewInt(int64(pc)))
        case oEXTRO:
            memAddr := vm.stack.Pop()
            contractAddr := vm.stack.Pop().Bytes()

            // Push the contract's memory on to the stack
            vm.stack.Push(contractMemory(state, contractAddr, memAddr))
        case oBALANCE:
            // Pushes the balance of the popped value on to the stack
            account := state.GetAccount(vm.stack.Pop().Bytes())
            vm.stack.Push(account.Amount)
        case oMKTX:
            addr, value := vm.stack.Popn()
            from, length := vm.stack.Popn()

            makeInlineTx(addr.Bytes(), value, from, length, contract, state)
        case oSUICIDE:
            recAddr := vm.stack.Pop().Bytes()
            // Purge all memory
            deletedMemory := contract.state.Purge()
            // Add refunds to the pop'ed address
            refund := new(big.Int).Mul(StoreFee, big.NewInt(int64(deletedMemory)))
            account := state.GetAccount(recAddr)
            account.Amount.Add(account.Amount, refund)
            // Update the refunding address
            state.UpdateAccount(recAddr, account)
            // Delete the contract
            state.trie.Update(string(addr), "")

            ethutil.Config.Log.Debugf("(%d) => %x\n", deletedMemory, recAddr)
            break out
        default:
            fmt.Printf("Invalid OPCODE: %x\n", op)
        }
        ethutil.Config.Log.Debugln("")
        //vm.stack.Print()
        pc++
    }

    state.UpdateContract(addr, contract)
}

func makeInlineTx(addr []byte, value, from, length *big.Int, contract *Contract, state *State) {
    ethutil.Config.Log.Debugf(" => creating inline tx %x %v %v %v", addr, value, from, length)
    j := 0
    dataItems := make([]string, int(length.Uint64()))
    for i := from.Uint64(); i < length.Uint64(); i++ {
        dataItems[j] = contract.GetMem(j).Str()
        j++
    }

    tx := NewTransaction(addr, value, dataItems)
    if tx.IsContract() {
        contract := MakeContract(tx, state)
        state.UpdateContract(tx.Hash()[12:], contract)
    } else {
        account := state.GetAccount(tx.Recipient)
        account.Amount.Add(account.Amount, tx.Value)
        state.UpdateAccount(tx.Recipient, account)
    }
}

// Returns an address from the specified contract's address
func contractMemory(state *State, contractAddr []byte, memAddr *big.Int) *big.Int {
    contract := state.GetContract(contractAddr)
    if contract == nil {
        log.Panicf("invalid contract addr %x", contractAddr)
    }
    val := state.trie.Get(memAddr.String())

    // decode the object as a big integer
    decoder := ethutil.NewValueFromBytes([]byte(val))
    if decoder.IsNil() {
        return ethutil.BigFalse
    }

    return decoder.BigInt()
}