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package vm
import (
"errors"
"fmt"
"math"
. "github.com/tendermint/tendermint/common"
"github.com/tendermint/tendermint/vm/sha3"
)
var (
ErrInsufficientBalance = errors.New("Insufficient balance")
ErrInvalidJumpDest = errors.New("Invalid jump dest")
ErrInsufficientGas = errors.New("Insuffient gas")
ErrMemoryOutOfBounds = errors.New("Memory out of bounds")
ErrCodeOutOfBounds = errors.New("Code out of bounds")
ErrInputOutOfBounds = errors.New("Input out of bounds")
ErrCallStackOverflow = errors.New("Call stack overflow")
ErrCallStackUnderflow = errors.New("Call stack underflow")
ErrDataStackOverflow = errors.New("Data stack overflow")
ErrDataStackUnderflow = errors.New("Data stack underflow")
ErrInvalidContract = errors.New("Invalid contract")
)
const (
dataStackCapacity = 1024
callStackCapacity = 100 // TODO ensure usage.
memoryCapacity = 1024 * 1024 // 1 MB
)
type VM struct {
appState AppState
params VMParams
callDepth int
}
type VMParams struct {
BlockHeight uint64
BlockHash Word
BlockTime int64
GasLimit uint64
CallStackLimit uint64
Origin Word
}
func NewVM(appState AppState, params VMParams) *VM {
return &VM{
appState: appState,
params: params,
callDepth: 0,
}
}
/*
// When running a transaction, the caller the pays for the fees.
// Check caller's account balance vs feeLimit and value
if caller.Balance < (feeLimit + value) {
return nil, ErrInsufficientBalance
}
caller.Balance -= (feeLimit + value)
*/
// gas: the maximum gas that will be run.
// When the function returns, *gas will be the amount of remaining gas.
func (vm *VM) Call(caller, callee *Account, code, input []byte, value uint64, gas *uint64) (output []byte, err error) {
if len(code) == 0 {
panic("Call() requires code")
}
fmt.Printf("(%d) (%X) %X (code=%d) gas: %v (d) %X\n", vm.callDepth, caller.Address[:4], callee.Address, len(callee.Code), *gas, input)
var (
pc uint64 = 0
stack = NewStack(dataStackCapacity, gas, &err)
memory = make([]byte, memoryCapacity)
ok = false // convenience
)
for {
var op = codeGetOp(code, pc)
fmt.Printf("(pc) %-3d (op) %-14s (st) %-4d ", pc, op.String(), stack.Len())
switch op {
case STOP: // 0x00
return nil, nil
case ADD: // 0x01
x, y := stack.Pop64(), stack.Pop64()
stack.Push64(x + y)
fmt.Printf(" %v + %v = %v\n", x, y, x+y)
case MUL: // 0x02
x, y := stack.Pop64(), stack.Pop64()
stack.Push64(x * y)
fmt.Printf(" %v * %v = %v\n", x, y, x*y)
case SUB: // 0x03
x, y := stack.Pop64(), stack.Pop64()
stack.Push64(x - y)
fmt.Printf(" %v - %v = %v\n", x, y, x-y)
case DIV: // 0x04
x, y := stack.Pop64(), stack.Pop64()
if y == 0 { // TODO
stack.Push(Zero)
fmt.Printf(" %v / %v = %v (TODO)\n", x, y, 0)
} else {
stack.Push64(x / y)
fmt.Printf(" %v / %v = %v\n", x, y, x/y)
}
case SDIV: // 0x05
x, y := int64(stack.Pop64()), int64(stack.Pop64())
if y == 0 { // TODO
stack.Push(Zero)
fmt.Printf(" %v / %v = %v (TODO)\n", x, y, 0)
} else {
stack.Push64(uint64(x / y))
fmt.Printf(" %v / %v = %v\n", x, y, x/y)
}
case MOD: // 0x06
x, y := stack.Pop64(), stack.Pop64()
if y == 0 { // TODO
stack.Push(Zero)
fmt.Printf(" %v %% %v = %v (TODO)\n", x, y, 0)
} else {
stack.Push64(x % y)
fmt.Printf(" %v %% %v = %v\n", x, y, x%y)
}
case SMOD: // 0x07
x, y := int64(stack.Pop64()), int64(stack.Pop64())
if y == 0 { // TODO
stack.Push(Zero)
fmt.Printf(" %v %% %v = %v (TODO)\n", x, y, 0)
} else {
stack.Push64(uint64(x % y))
fmt.Printf(" %v %% %v = %v\n", x, y, x%y)
}
case ADDMOD: // 0x08
x, y, z := stack.Pop64(), stack.Pop64(), stack.Pop64()
if z == 0 { // TODO
stack.Push(Zero)
fmt.Printf(" (%v + %v) %% %v = %v (TODO)\n", x, y, z, 0)
} else {
stack.Push64(x % y)
fmt.Printf(" (%v + %v) %% %v = %v\n", x, y, z, (x+y)%z)
}
case MULMOD: // 0x09
x, y, z := stack.Pop64(), stack.Pop64(), stack.Pop64()
if z == 0 { // TODO
stack.Push(Zero)
fmt.Printf(" (%v + %v) %% %v = %v (TODO)\n", x, y, z, 0)
} else {
stack.Push64(x % y)
fmt.Printf(" (%v + %v) %% %v = %v\n", x, y, z, (x*y)%z)
}
case EXP: // 0x0A
x, y := stack.Pop64(), stack.Pop64()
stack.Push64(ExpUint64(x, y))
fmt.Printf(" %v ** %v = %v\n", x, y, uint64(math.Pow(float64(x), float64(y))))
case SIGNEXTEND: // 0x0B
x, y := stack.Pop64(), stack.Pop64()
res := (y << uint(x)) >> x
stack.Push64(res)
fmt.Printf(" (%v << %v) >> %v = %v\n", y, x, x, res)
case LT: // 0x10
x, y := stack.Pop64(), stack.Pop64()
if x < y {
stack.Push64(1)
} else {
stack.Push(Zero)
}
fmt.Printf(" %v < %v = %v\n", x, y, x < y)
case GT: // 0x11
x, y := stack.Pop64(), stack.Pop64()
if x > y {
stack.Push64(1)
} else {
stack.Push(Zero)
}
fmt.Printf(" %v > %v = %v\n", x, y, x > y)
case SLT: // 0x12
x, y := int64(stack.Pop64()), int64(stack.Pop64())
if x < y {
stack.Push64(1)
} else {
stack.Push(Zero)
}
fmt.Printf(" %v < %v = %v\n", x, y, x < y)
case SGT: // 0x13
x, y := int64(stack.Pop64()), int64(stack.Pop64())
if x > y {
stack.Push64(1)
} else {
stack.Push(Zero)
}
fmt.Printf(" %v > %v = %v\n", x, y, x > y)
case EQ: // 0x14
x, y := stack.Pop64(), stack.Pop64()
if x > y {
stack.Push64(1)
} else {
stack.Push(Zero)
}
fmt.Printf(" %v == %v = %v\n", x, y, x == y)
case ISZERO: // 0x15
x := stack.Pop64()
if x == 0 {
stack.Push64(1)
} else {
stack.Push(Zero)
}
fmt.Printf(" %v == 0 = %v\n", x, x == 0)
case AND: // 0x16
x, y := stack.Pop64(), stack.Pop64()
stack.Push64(x & y)
fmt.Printf(" %v & %v = %v\n", x, y, x&y)
case OR: // 0x17
x, y := stack.Pop64(), stack.Pop64()
stack.Push64(x | y)
fmt.Printf(" %v | %v = %v\n", x, y, x|y)
case XOR: // 0x18
x, y := stack.Pop64(), stack.Pop64()
stack.Push64(x ^ y)
fmt.Printf(" %v ^ %v = %v\n", x, y, x^y)
case NOT: // 0x19
x := stack.Pop64()
stack.Push64(^x)
fmt.Printf(" !%v = %v\n", x, ^x)
case BYTE: // 0x1A
idx, val := stack.Pop64(), stack.Pop()
res := byte(0)
if idx < 32 {
res = val[idx]
}
stack.Push64(uint64(res))
fmt.Printf(" => 0x%X\n", res)
case SHA3: // 0x20
if ok = useGas(gas, GasSha3); !ok {
return nil, firstErr(err, ErrInsufficientGas)
}
offset, size := stack.Pop64(), stack.Pop64()
data, ok := subslice(memory, offset, size)
if !ok {
return nil, firstErr(err, ErrMemoryOutOfBounds)
}
data = sha3.Sha3(data)
stack.PushBytes(data)
fmt.Printf(" => (%v) %X\n", size, data)
case ADDRESS: // 0x30
stack.Push(callee.Address)
fmt.Printf(" => %X\n", callee.Address)
case BALANCE: // 0x31
addr := stack.Pop()
if ok = useGas(gas, GasGetAccount); !ok {
return nil, firstErr(err, ErrInsufficientGas)
}
account, err_ := vm.appState.GetAccount(addr) // TODO ensure that 20byte lengths are supported.
if err = firstErr(err, err_); err != nil {
return nil, err
}
balance := account.Balance
stack.Push64(balance)
fmt.Printf(" => %v (%X)\n", balance, addr)
case ORIGIN: // 0x32
origin := vm.params.Origin
stack.Push(origin)
fmt.Printf(" => %X\n", origin)
case CALLER: // 0x33
stack.Push(caller.Address)
fmt.Printf(" => %X\n", caller.Address)
case CALLVALUE: // 0x34
stack.Push64(value)
fmt.Printf(" => %v\n", value)
case CALLDATALOAD: // 0x35
offset := stack.Pop64()
data, ok := subslice(input, offset, 32)
if !ok {
return nil, firstErr(err, ErrInputOutOfBounds)
}
stack.Push(RightPadWord(data))
fmt.Printf(" => 0x%X\n", data)
case CALLDATASIZE: // 0x36
stack.Push64(uint64(len(input)))
fmt.Printf(" => %d\n", len(input))
case CALLDATACOPY: // 0x37
memOff := stack.Pop64()
inputOff := stack.Pop64()
length := stack.Pop64()
data, ok := subslice(input, inputOff, length)
if !ok {
return nil, firstErr(err, ErrInputOutOfBounds)
}
dest, ok := subslice(memory, memOff, length)
if !ok {
return nil, firstErr(err, ErrMemoryOutOfBounds)
}
copy(dest, data)
fmt.Printf(" => [%v, %v, %v] %X\n", memOff, inputOff, length, data)
case CODESIZE: // 0x38
l := uint64(len(code))
stack.Push64(l)
fmt.Printf(" => %d\n", l)
case CODECOPY: // 0x39
memOff := stack.Pop64()
codeOff := stack.Pop64()
length := stack.Pop64()
data, ok := subslice(code, codeOff, length)
if !ok {
return nil, firstErr(err, ErrCodeOutOfBounds)
}
dest, ok := subslice(memory, memOff, length)
if !ok {
return nil, firstErr(err, ErrMemoryOutOfBounds)
}
copy(dest, data)
fmt.Printf(" => [%v, %v, %v] %X\n", memOff, codeOff, length, data)
case GASPRICE_DEPRECATED: // 0x3A
stack.Push(Zero)
fmt.Printf(" => %X (GASPRICE IS DEPRECATED)\n")
case EXTCODESIZE: // 0x3B
addr := stack.Pop()
if ok = useGas(gas, GasGetAccount); !ok {
return nil, firstErr(err, ErrInsufficientGas)
}
account, err_ := vm.appState.GetAccount(addr)
if err = firstErr(err, err_); err != nil {
return nil, err
}
code := account.Code
l := uint64(len(code))
stack.Push64(l)
fmt.Printf(" => %d\n", l)
case EXTCODECOPY: // 0x3C
addr := stack.Pop()
if ok = useGas(gas, GasGetAccount); !ok {
return nil, firstErr(err, ErrInsufficientGas)
}
account, err_ := vm.appState.GetAccount(addr)
if err = firstErr(err, err_); err != nil {
return nil, err
}
code := account.Code
memOff := stack.Pop64()
codeOff := stack.Pop64()
length := stack.Pop64()
data, ok := subslice(code, codeOff, length)
if !ok {
return nil, ErrCodeOutOfBounds
}
dest, ok := subslice(memory, memOff, length)
if !ok {
return nil, ErrMemoryOutOfBounds
}
copy(dest, data)
fmt.Printf(" => [%v, %v, %v] %X\n", memOff, codeOff, length, data)
case BLOCKHASH: // 0x40
stack.Push(Zero)
fmt.Printf(" => 0x%X (NOT SUPPORTED)\n", stack.Peek().Bytes())
case COINBASE: // 0x41
stack.Push(Zero)
fmt.Printf(" => 0x%X (NOT SUPPORTED)\n", stack.Peek().Bytes())
case TIMESTAMP: // 0x42
time := vm.params.BlockTime
stack.Push64(uint64(time))
fmt.Printf(" => 0x%X\n", time)
case BLOCKHEIGHT: // 0x43
number := uint64(vm.params.BlockHeight)
stack.Push64(number)
fmt.Printf(" => 0x%X\n", number)
case GASLIMIT: // 0x45
stack.Push64(vm.params.GasLimit)
fmt.Printf(" => %v\n", vm.params.GasLimit)
case POP: // 0x50
stack.Pop()
fmt.Printf(" => %v\n", vm.params.GasLimit)
case MLOAD: // 0x51
offset := stack.Pop64()
data, ok := subslice(memory, offset, 32)
if !ok {
return nil, ErrMemoryOutOfBounds
}
stack.Push(RightPadWord(data))
fmt.Printf(" => 0x%X\n", data)
case MSTORE: // 0x52
offset, data := stack.Pop64(), stack.Pop()
dest, ok := subslice(memory, offset, 32)
if !ok {
return nil, ErrMemoryOutOfBounds
}
copy(dest, data[:])
fmt.Printf(" => 0x%X\n", data)
case MSTORE8: // 0x53
offset, val := stack.Pop64(), byte(stack.Pop64()&0xFF)
if len(memory) <= int(offset) {
return nil, ErrMemoryOutOfBounds
}
memory[offset] = val
fmt.Printf(" => [%v] 0x%X\n", offset, val)
case SLOAD: // 0x54
loc := stack.Pop()
data, _ := vm.appState.GetStorage(callee.Address, loc)
stack.Push(data)
fmt.Printf(" {0x%X : 0x%X}\n", loc, data)
case SSTORE: // 0x55
loc, data := stack.Pop(), stack.Pop()
updated, err_ := vm.appState.SetStorage(callee.Address, loc, data)
if err = firstErr(err, err_); err != nil {
return nil, err
}
if updated {
useGas(gas, GasStorageUpdate)
} else {
useGas(gas, GasStorageCreate)
}
fmt.Printf(" {0x%X : 0x%X}\n", loc, data)
case JUMP: // 0x56
err = jump(code, stack.Pop64())
continue
case JUMPI: // 0x57
pos, cond := stack.Pop64(), stack.Pop64()
if cond >= 1 {
err = jump(code, pos)
continue
}
fmt.Printf(" ~> false\n")
case PC: // 0x58
stack.Push64(pc)
case MSIZE: // 0x59
stack.Push64(uint64(len(memory)))
case GAS: // 0x5A
stack.Push64(*gas)
fmt.Printf(" => %X\n", *gas)
case JUMPDEST: // 0x5B
// Do nothing
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 := uint64(op - PUSH1 + 1)
codeSegment, ok := subslice(code, pc+1, a)
if !ok {
return nil, firstErr(err, ErrCodeOutOfBounds)
}
res := RightPadWord(codeSegment)
stack.Push(res)
pc += a
fmt.Printf(" => 0x%X\n", res)
case DUP1, DUP2, DUP3, DUP4, DUP5, DUP6, DUP7, DUP8, DUP9, DUP10, DUP11, DUP12, DUP13, DUP14, DUP15, DUP16:
n := int(op - DUP1 + 1)
stack.Dup(n)
fmt.Printf(" => [%d] 0x%X\n", n, stack.Peek().Bytes())
case SWAP1, SWAP2, SWAP3, SWAP4, SWAP5, SWAP6, SWAP7, SWAP8, SWAP9, SWAP10, SWAP11, SWAP12, SWAP13, SWAP14, SWAP15, SWAP16:
n := int(op - SWAP1 + 2)
stack.Swap(n)
fmt.Printf(" => [%d]\n", n)
case LOG0, LOG1, LOG2, LOG3, LOG4:
n := int(op - LOG0)
topics := make([]Word, n)
offset, size := stack.Pop64(), stack.Pop64()
for i := 0; i < n; i++ {
topics[i] = stack.Pop()
}
data, ok := subslice(memory, offset, size)
if !ok {
return nil, firstErr(err, ErrMemoryOutOfBounds)
}
log := &Log{
callee.Address,
topics,
data,
vm.params.BlockHeight,
}
vm.appState.AddLog(log)
fmt.Printf(" => %v\n", log)
case CREATE: // 0xF0
value := stack.Pop64()
offset, size := stack.Pop64(), stack.Pop64()
input, ok := subslice(memory, offset, size)
if !ok {
return nil, firstErr(err, ErrMemoryOutOfBounds)
}
// Check balance
if caller.Balance < value {
return nil, firstErr(err, ErrInsufficientBalance)
} else {
caller.Balance -= value
}
// Create a new address
nonce := caller.Nonce
addr := createAddress(caller.Address, nonce)
caller.Nonce += 1
// TODO charge for gas to create account _ the code length * GasCreateByte
newAccount, err := vm.appState.CreateAccount(addr, value)
if err != nil {
stack.Push(Zero)
fmt.Printf(" (*) 0x0 %v\n", err)
} else {
// Run the input to get the contract code.
// The code as well as the input to the code are the same.
ret, err_ := vm.Call(callee, newAccount, input, input, value, gas)
if err_ != nil {
caller.Balance += value // Return the balance
stack.Push(Zero)
} else {
newAccount.Code = ret // Set the code
stack.Push(newAccount.Address)
}
}
case CALL, CALLCODE: // 0xF1, 0xF2
gasLimit := stack.Pop64()
addr, value := stack.Pop(), stack.Pop64()
inOffset, inSize := stack.Pop64(), stack.Pop64() // inputs
retOffset, retSize := stack.Pop64(), stack.Pop64() // outputs
fmt.Printf(" => %X\n", addr)
// Get the arguments from the memory
args, ok := subslice(memory, inOffset, inSize)
if !ok {
return nil, firstErr(err, ErrMemoryOutOfBounds)
}
// Ensure that gasLimit is reasonable
if *gas < gasLimit {
return nil, firstErr(err, ErrInsufficientGas)
} else {
*gas -= gasLimit
// NOTE: we will return any used gas later.
}
// Begin execution
var ret []byte
var err error
// If addr is in nativeContracts
if nativeContract := nativeContracts[addr]; nativeContract != nil {
ret, err = nativeContract(args, &gasLimit)
} else {
if ok = useGas(gas, GasGetAccount); !ok {
return nil, firstErr(err, ErrInsufficientGas)
}
account, err_ := vm.appState.GetAccount(addr)
if err = firstErr(err, err_); err != nil {
return nil, err
}
if op == CALLCODE {
ret, err = vm.Call(callee, callee, account.Code, args, value, gas)
} else {
ret, err = vm.Call(callee, account, account.Code, args, value, gas)
}
}
// Push result
if err != nil {
stack.Push(Zero)
} else {
stack.Push(One)
dest, ok := subslice(memory, retOffset, retSize)
if !ok {
return nil, firstErr(err, ErrMemoryOutOfBounds)
}
copy(dest, ret)
}
// Handle remaining gas.
*gas += gasLimit
fmt.Printf("resume %X (%v)\n", callee.Address, gas)
case RETURN: // 0xF3
offset, size := stack.Pop64(), stack.Pop64()
ret, ok := subslice(memory, offset, size)
if !ok {
return nil, firstErr(err, ErrMemoryOutOfBounds)
}
fmt.Printf(" => [%v, %v] (%d) 0x%X\n", offset, size, len(ret), ret)
return ret, nil
case SUICIDE: // 0xFF
addr := stack.Pop()
if ok = useGas(gas, GasGetAccount); !ok {
return nil, firstErr(err, ErrInsufficientGas)
}
receiver, err_ := vm.appState.GetAccount(addr)
if err = firstErr(err, err_); err != nil {
return nil, err
}
balance := callee.Balance
receiver.Balance += balance
vm.appState.UpdateAccount(receiver)
vm.appState.DeleteAccount(callee)
fmt.Printf(" => (%X) %v\n", addr[:4], balance)
fallthrough
default:
fmt.Printf("(pc) %-3v Invalid opcode %X\n", pc, op)
panic(fmt.Errorf("Invalid opcode %X", op))
}
pc++
// If there is an error, return
if err != nil {
return nil, err
}
}
}
func subslice(data []byte, offset, length uint64) ([]byte, bool) {
size := uint64(len(data))
if size < offset {
return nil, false
} else if size < offset+length {
return data[offset:], false
} else {
return data[offset : offset+length], true
}
}
func codeGetOp(code []byte, n uint64) OpCode {
if uint64(len(code)) <= n {
return OpCode(0) // stop
} else {
return OpCode(code[n])
}
}
func jump(code []byte, to uint64) (err error) {
dest := codeGetOp(code, to)
if dest != JUMPDEST {
return ErrInvalidJumpDest
}
fmt.Printf(" ~> %v\n", to)
return nil
}
func firstErr(errA, errB error) error {
if errA != nil {
return errA
} else {
return errB
}
}
func useGas(gas *uint64, gasToUse uint64) bool {
if *gas > gasToUse {
*gas -= gasToUse
return true
} else {
return false
}
}
// Creates a 20 byte address from the creatorAddr and nonce.
func createAddress(creatorAddr Word, nonce uint64) Word {
temp := make([]byte, 32+8)
copy(temp, creatorAddr[:])
PutUint64(temp[32:], nonce)
return RightPadWord(sha3.Sha3(temp)[:20])
}