package vm import ( "fmt" "math" "math/big" "github.com/ethereum/go-ethereum/crypto" "github.com/ethereum/go-ethereum/ethutil" "github.com/ethereum/go-ethereum/state" ) type DebugVm struct { env Environment logTy byte logStr string err error // Debugging Dbg Debugger BreakPoints []int64 Stepping bool Fn string Recoverable bool } func NewDebugVm(env Environment) *DebugVm { lt := LogTyPretty if ethutil.Config.Diff { lt = LogTyDiff } return &DebugVm{env: env, logTy: lt, Recoverable: true} } func (self *DebugVm) Run(me, caller ClosureRef, code []byte, value, gas, price *big.Int, callData []byte) (ret []byte, err error) { self.env.SetDepth(self.env.Depth() + 1) msg := self.env.State().Manifest().AddMessage(&state.Message{ To: me.Address(), From: caller.Address(), Input: callData, Origin: self.env.Origin(), Block: self.env.BlockHash(), Timestamp: self.env.Time(), Coinbase: self.env.Coinbase(), Number: self.env.BlockNumber(), Value: value, }) closure := NewClosure(msg, caller, me, code, gas, price) if p := Precompiled[string(me.Address())]; p != nil { return self.RunPrecompiled(p, callData, closure) } if self.Recoverable { // Recover from any require exception defer func() { if r := recover(); r != nil { self.Endl() closure.UseGas(closure.Gas) ret = closure.Return(nil) err = fmt.Errorf("%v", r) } }() } var ( op OpCode destinations = analyseJumpDests(closure.Code) mem = NewMemory() stack = NewStack() pc uint64 = 0 step = 0 prevStep = 0 statedb = self.env.State() require = func(m int) { if stack.Len() < m { panic(fmt.Sprintf("%04v (%v) stack err size = %d, required = %d", pc, op, stack.Len(), m)) } } jump = func(from uint64, to *big.Int) { p := to.Uint64() self.Printf(" ~> %v", to) // Return to start if p == 0 { pc = 0 } else { nop := OpCode(closure.GetOp(p)) if !(nop == JUMPDEST || destinations[from] != nil) { panic(fmt.Sprintf("invalid jump destination (%v) %v", nop, p)) } else if nop == JUMP || nop == JUMPI { panic(fmt.Sprintf("not allowed to JUMP(I) in to JUMP")) } pc = to.Uint64() } self.Endl() } ) // Don't bother with the execution if there's no code. if len(code) == 0 { return closure.Return(nil), nil } vmlogger.Debugf("(%d) (%x) %x gas: %v (d) %x\n", self.env.Depth(), caller.Address()[:4], closure.Address(), closure.Gas, callData) for { prevStep = step // The base for all big integer arithmetic base := new(big.Int) step++ // Get the memory location of pc op = closure.GetOp(pc) gas := new(big.Int) addStepGasUsage := func(amount *big.Int) { if amount.Cmp(ethutil.Big0) >= 0 { gas.Add(gas, amount) } } addStepGasUsage(GasStep) var newMemSize *big.Int = ethutil.Big0 // Stack Check, memory resize & gas phase switch op { // Stack checks only case ISZERO, CALLDATALOAD, POP, JUMP, NOT: // 1 require(1) case ADD, SUB, DIV, SDIV, MOD, SMOD, LT, GT, SLT, SGT, EQ, AND, OR, XOR, BYTE: // 2 require(2) case ADDMOD, MULMOD: // 3 require(3) case SWAP1, SWAP2, SWAP3, SWAP4, SWAP5, SWAP6, SWAP7, SWAP8, SWAP9, SWAP10, SWAP11, SWAP12, SWAP13, SWAP14, SWAP15, SWAP16: n := int(op - SWAP1 + 2) require(n) case DUP1, DUP2, DUP3, DUP4, DUP5, DUP6, DUP7, DUP8, DUP9, DUP10, DUP11, DUP12, DUP13, DUP14, DUP15, DUP16: n := int(op - DUP1 + 1) require(n) case LOG0, LOG1, LOG2, LOG3, LOG4: n := int(op - LOG0) require(n + 2) gas.Set(GasLog) addStepGasUsage(new(big.Int).Mul(big.NewInt(int64(n)), GasLog)) mSize, mStart := stack.Peekn() addStepGasUsage(mSize) newMemSize = calcMemSize(mStart, mSize) case EXP: require(2) gas.Set(big.NewInt(int64(len(stack.data[stack.Len()-2].Bytes()) + 1))) // Gas only case STOP: gas.Set(ethutil.Big0) case SUICIDE: require(1) gas.Set(ethutil.Big0) case SLOAD: require(1) gas.Set(GasSLoad) // Memory resize & Gas case SSTORE: require(2) var mult *big.Int y, x := stack.Peekn() val := closure.GetStorage(x) if val.BigInt().Cmp(ethutil.Big0) == 0 && len(y.Bytes()) > 0 { // 0 => non 0 mult = ethutil.Big3 } else if val.BigInt().Cmp(ethutil.Big0) != 0 && len(y.Bytes()) == 0 { statedb.Refund(caller.Address(), GasSStoreRefund) mult = ethutil.Big0 } else { // non 0 => non 0 (or 0 => 0) mult = ethutil.Big1 } gas.Set(new(big.Int).Mul(mult, GasSStore)) case BALANCE: require(1) gas.Set(GasBalance) case MSTORE: require(2) newMemSize = calcMemSize(stack.Peek(), u256(32)) case MLOAD: require(1) newMemSize = calcMemSize(stack.Peek(), u256(32)) case MSTORE8: require(2) newMemSize = calcMemSize(stack.Peek(), u256(1)) case RETURN: require(2) newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-2]) case SHA3: require(2) gas.Set(GasSha) newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-2]) case CALLDATACOPY: require(2) newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-3]) case CODECOPY: require(3) newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-3]) case EXTCODECOPY: require(4) newMemSize = calcMemSize(stack.data[stack.Len()-2], stack.data[stack.Len()-4]) case CALL, CALLCODE: require(7) gas.Set(GasCall) addStepGasUsage(stack.data[stack.Len()-1]) x := calcMemSize(stack.data[stack.Len()-6], stack.data[stack.Len()-7]) y := calcMemSize(stack.data[stack.Len()-4], stack.data[stack.Len()-5]) newMemSize = ethutil.BigMax(x, y) case CREATE: require(3) gas.Set(GasCreate) newMemSize = calcMemSize(stack.data[stack.Len()-2], stack.data[stack.Len()-3]) } if newMemSize.Cmp(ethutil.Big0) > 0 { newMemSize.Add(newMemSize, u256(31)) newMemSize.Div(newMemSize, u256(32)) newMemSize.Mul(newMemSize, u256(32)) switch op { case CALLDATACOPY, CODECOPY, EXTCODECOPY: addStepGasUsage(new(big.Int).Div(newMemSize, u256(32))) case SHA3: g := new(big.Int).Div(newMemSize, u256(32)) g.Mul(g, GasSha3Byte) addStepGasUsage(g) } if newMemSize.Cmp(u256(int64(mem.Len()))) > 0 { memGasUsage := new(big.Int).Sub(newMemSize, u256(int64(mem.Len()))) memGasUsage.Mul(GasMemory, memGasUsage) memGasUsage.Div(memGasUsage, u256(32)) addStepGasUsage(memGasUsage) } } self.Printf("(pc) %-3d -o- %-14s", pc, op.String()) self.Printf(" (m) %-4d (s) %-4d (g) %-3v (%v)", mem.Len(), stack.Len(), gas, closure.Gas) if !closure.UseGas(gas) { self.Endl() tmp := new(big.Int).Set(closure.Gas) closure.UseGas(closure.Gas) return closure.Return(nil), OOG(gas, tmp) } mem.Resize(newMemSize.Uint64()) switch op { // 0x20 range case ADD: x, y := stack.Popn() self.Printf(" %v + %v", y, x) base.Add(y, x) U256(base) self.Printf(" = %v", base) // Pop result back on the stack stack.Push(base) case SUB: x, y := stack.Popn() self.Printf(" %v - %v", y, x) base.Sub(y, x) U256(base) self.Printf(" = %v", base) // Pop result back on the stack stack.Push(base) case MUL: x, y := stack.Popn() self.Printf(" %v * %v", y, x) base.Mul(y, x) U256(base) self.Printf(" = %v", base) // Pop result back on the stack stack.Push(base) case DIV: x, y := stack.Pop(), stack.Pop() self.Printf(" %v / %v", x, y) if y.Cmp(ethutil.Big0) != 0 { base.Div(x, y) } U256(base) self.Printf(" = %v", base) // Pop result back on the stack stack.Push(base) case SDIV: x, y := S256(stack.Pop()), S256(stack.Pop()) self.Printf(" %v / %v", x, y) if y.Cmp(ethutil.Big0) == 0 { base.Set(ethutil.Big0) } else { n := new(big.Int) if new(big.Int).Mul(x, y).Cmp(ethutil.Big0) < 0 { n.SetInt64(-1) } else { n.SetInt64(1) } base.Div(x.Abs(x), y.Abs(y)).Mul(base, n) U256(base) } self.Printf(" = %v", base) stack.Push(base) case MOD: x, y := stack.Pop(), stack.Pop() self.Printf(" %v %% %v", x, y) if y.Cmp(ethutil.Big0) == 0 { base.Set(ethutil.Big0) } else { base.Mod(x, y) } U256(base) self.Printf(" = %v", base) stack.Push(base) case SMOD: x, y := S256(stack.Pop()), S256(stack.Pop()) self.Printf(" %v %% %v", x, y) if y.Cmp(ethutil.Big0) == 0 { base.Set(ethutil.Big0) } else { n := new(big.Int) if x.Cmp(ethutil.Big0) < 0 { n.SetInt64(-1) } else { n.SetInt64(1) } base.Mod(x.Abs(x), y.Abs(y)).Mul(base, n) U256(base) } self.Printf(" = %v", base) stack.Push(base) case EXP: x, y := stack.Popn() self.Printf(" %v ** %v", y, x) base.Exp(y, x, Pow256) U256(base) self.Printf(" = %v", base) stack.Push(base) case SIGNEXTEND: back := stack.Pop().Uint64() if back < 31 { bit := uint(back*8 + 7) num := stack.Pop() mask := new(big.Int).Lsh(ethutil.Big1, bit) mask.Sub(mask, ethutil.Big1) if ethutil.BitTest(num, int(bit)) { num.Or(num, mask.Not(mask)) } else { num.And(num, mask) } num = U256(num) self.Printf(" = %v", num) stack.Push(num) } case NOT: base.Sub(Pow256, stack.Pop()).Sub(base, ethutil.Big1) // Not needed //base = U256(base) stack.Push(base) case LT: x, y := stack.Popn() self.Printf(" %v < %v", y, x) // x < y if y.Cmp(x) < 0 { stack.Push(ethutil.BigTrue) } else { stack.Push(ethutil.BigFalse) } case GT: x, y := stack.Popn() self.Printf(" %v > %v", y, x) // x > y if y.Cmp(x) > 0 { stack.Push(ethutil.BigTrue) } else { stack.Push(ethutil.BigFalse) } case SLT: y, x := S256(stack.Pop()), S256(stack.Pop()) self.Printf(" %v < %v", y, x) // x < y if y.Cmp(S256(x)) < 0 { stack.Push(ethutil.BigTrue) } else { stack.Push(ethutil.BigFalse) } case SGT: y, x := S256(stack.Pop()), S256(stack.Pop()) self.Printf(" %v > %v", y, x) // x > y if y.Cmp(x) > 0 { stack.Push(ethutil.BigTrue) } else { stack.Push(ethutil.BigFalse) } case EQ: x, y := stack.Popn() self.Printf(" %v == %v", y, x) // x == y if x.Cmp(y) == 0 { stack.Push(ethutil.BigTrue) } else { stack.Push(ethutil.BigFalse) } case ISZERO: x := stack.Pop() if x.Cmp(ethutil.BigFalse) > 0 { stack.Push(ethutil.BigFalse) } else { stack.Push(ethutil.BigTrue) } // 0x10 range case AND: x, y := stack.Popn() self.Printf(" %v & %v", y, x) stack.Push(base.And(y, x)) case OR: x, y := stack.Popn() self.Printf(" %v | %v", y, x) stack.Push(base.Or(y, x)) case XOR: x, y := stack.Popn() self.Printf(" %v ^ %v", y, x) stack.Push(base.Xor(y, x)) case BYTE: val, th := stack.Popn() if th.Cmp(big.NewInt(32)) < 0 { byt := big.NewInt(int64(ethutil.LeftPadBytes(val.Bytes(), 32)[th.Int64()])) base.Set(byt) } else { base.Set(ethutil.BigFalse) } self.Printf(" => 0x%x", base.Bytes()) stack.Push(base) case ADDMOD: x := stack.Pop() y := stack.Pop() z := stack.Pop() base.Add(x, y) base.Mod(base, z) U256(base) self.Printf(" = %v", base) stack.Push(base) case MULMOD: x := stack.Pop() y := stack.Pop() z := stack.Pop() base.Mul(x, y) base.Mod(base, z) U256(base) self.Printf(" = %v", base) stack.Push(base) // 0x20 range case SHA3: size, offset := stack.Popn() data := crypto.Sha3(mem.Get(offset.Int64(), size.Int64())) stack.Push(ethutil.BigD(data)) self.Printf(" => %x", data) // 0x30 range case ADDRESS: stack.Push(ethutil.BigD(closure.Address())) self.Printf(" => %x", closure.Address()) case BALANCE: addr := stack.Pop().Bytes() balance := statedb.GetBalance(addr) stack.Push(balance) self.Printf(" => %v (%x)", balance, addr) case ORIGIN: origin := self.env.Origin() stack.Push(ethutil.BigD(origin)) self.Printf(" => %x", origin) case CALLER: caller := closure.caller.Address() stack.Push(ethutil.BigD(caller)) self.Printf(" => %x", caller) case CALLVALUE: stack.Push(value) self.Printf(" => %v", value) case CALLDATALOAD: var ( offset = stack.Pop() data = make([]byte, 32) lenData = big.NewInt(int64(len(callData))) ) if lenData.Cmp(offset) >= 0 { length := new(big.Int).Add(offset, ethutil.Big32) length = ethutil.BigMin(length, lenData) copy(data, callData[offset.Int64():length.Int64()]) } self.Printf(" => 0x%x", data) stack.Push(ethutil.BigD(data)) case CALLDATASIZE: l := int64(len(callData)) stack.Push(big.NewInt(l)) self.Printf(" => %d", l) case CALLDATACOPY: var ( size = uint64(len(callData)) mOff = stack.Pop().Uint64() cOff = stack.Pop().Uint64() l = stack.Pop().Uint64() ) if cOff > size { cOff = 0 l = 0 } else if cOff+l > size { l = 0 } code := callData[cOff : cOff+l] mem.Set(mOff, l, code) self.Printf(" => [%v, %v, %v] %x", mOff, cOff, l, callData[cOff:cOff+l]) case CODESIZE, EXTCODESIZE: var code []byte if op == EXTCODESIZE { addr := stack.Pop().Bytes() code = statedb.GetCode(addr) } else { code = closure.Code } l := big.NewInt(int64(len(code))) stack.Push(l) self.Printf(" => %d", l) case CODECOPY, EXTCODECOPY: var code []byte if op == EXTCODECOPY { addr := stack.Pop().Bytes() code = statedb.GetCode(addr) } else { code = closure.Code } var ( size = uint64(len(code)) mOff = stack.Pop().Uint64() cOff = stack.Pop().Uint64() l = stack.Pop().Uint64() ) if cOff > size { cOff = 0 l = 0 } else if cOff+l > size { l = uint64(math.Min(float64(cOff+l), float64(size))) } codeCopy := code[cOff : cOff+l] mem.Set(mOff, l, codeCopy) self.Printf(" => [%v, %v, %v] %x", mOff, cOff, l, code[cOff:cOff+l]) case GASPRICE: stack.Push(closure.Price) self.Printf(" => %v", closure.Price) // 0x40 range case PREVHASH: prevHash := self.env.PrevHash() stack.Push(ethutil.BigD(prevHash)) self.Printf(" => 0x%x", prevHash) case COINBASE: coinbase := self.env.Coinbase() stack.Push(ethutil.BigD(coinbase)) self.Printf(" => 0x%x", coinbase) case TIMESTAMP: time := self.env.Time() stack.Push(big.NewInt(time)) self.Printf(" => 0x%x", time) case NUMBER: number := self.env.BlockNumber() stack.Push(number) self.Printf(" => 0x%x", number.Bytes()) case DIFFICULTY: difficulty := self.env.Difficulty() stack.Push(difficulty) self.Printf(" => 0x%x", difficulty.Bytes()) case GASLIMIT: stack.Push(self.env.GasLimit()) // 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) a := uint64(op - PUSH1 + 1) //pc.Add(pc, ethutil.Big1) data := closure.GetRangeValue(pc+1, a) val := ethutil.BigD(data.Bytes()) // Push value to stack stack.Push(val) pc += a //pc.Add(pc, a.Sub(a, big.NewInt(1))) step += int(op) - int(PUSH1) + 1 self.Printf(" => 0x%x", data.Bytes()) case POP: stack.Pop() case DUP1, DUP2, DUP3, DUP4, DUP5, DUP6, DUP7, DUP8, DUP9, DUP10, DUP11, DUP12, DUP13, DUP14, DUP15, DUP16: n := int(op - DUP1 + 1) stack.Dupn(n) self.Printf(" => [%d] 0x%x", 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) x, y := stack.Swapn(n) self.Printf(" => [%d] %x [0] %x", n, x.Bytes(), y.Bytes()) case LOG0, LOG1, LOG2, LOG3, LOG4: n := int(op - LOG0) topics := make([][]byte, n) mSize, mStart := stack.Popn() for i := 0; i < n; i++ { topics[i] = ethutil.LeftPadBytes(stack.Pop().Bytes(), 32) } data := mem.Geti(mStart.Int64(), mSize.Int64()) log := &Log{closure.Address(), topics, data} self.env.AddLog(log) self.Printf(" => %v", log) case MLOAD: offset := stack.Pop() val := ethutil.BigD(mem.Get(offset.Int64(), 32)) stack.Push(val) self.Printf(" => 0x%x", val.Bytes()) case MSTORE: // Store the value at stack top-1 in to memory at location stack top // Pop value of the stack val, mStart := stack.Popn() mem.Set(mStart.Uint64(), 32, ethutil.BigToBytes(val, 256)) self.Printf(" => 0x%x", val) case MSTORE8: off := stack.Pop() val := stack.Pop() mem.store[off.Int64()] = byte(val.Int64() & 0xff) self.Printf(" => [%v] 0x%x", off, val) case SLOAD: loc := stack.Pop() val := ethutil.BigD(statedb.GetState(closure.Address(), loc.Bytes())) stack.Push(val) self.Printf(" {0x%x : 0x%x}", loc.Bytes(), val.Bytes()) case SSTORE: val, loc := stack.Popn() statedb.SetState(closure.Address(), loc.Bytes(), val) closure.message.AddStorageChange(loc.Bytes()) self.Printf(" {0x%x : 0x%x}", loc.Bytes(), val.Bytes()) case JUMP: jump(pc, stack.Pop()) continue case JUMPI: cond, pos := stack.Popn() if cond.Cmp(ethutil.BigTrue) >= 0 { jump(pc, pos) continue } case JUMPDEST: case PC: stack.Push(big.NewInt(int64(pc))) case MSIZE: stack.Push(big.NewInt(int64(mem.Len()))) case GAS: stack.Push(closure.Gas) // 0x60 range case CREATE: var ( err error value = stack.Pop() size, offset = stack.Popn() input = mem.Get(offset.Int64(), size.Int64()) gas = new(big.Int).Set(closure.Gas) // Snapshot the current stack so we are able to // revert back to it later. //snapshot = self.env.State().Copy() ) // Generate a new address n := statedb.GetNonce(closure.Address()) addr := crypto.CreateAddress(closure.Address(), n) statedb.SetNonce(closure.Address(), n+1) self.Printf(" (*) %x", addr).Endl() closure.UseGas(closure.Gas) ret, err, ref := self.env.Create(closure, addr, input, gas, price, value) if err != nil { stack.Push(ethutil.BigFalse) self.Printf("CREATE err %v", err) } else { // gas < len(ret) * CreateDataGas == NO_CODE dataGas := big.NewInt(int64(len(ret))) dataGas.Mul(dataGas, GasCreateByte) if closure.UseGas(dataGas) { ref.SetCode(ret) msg.Output = ret } stack.Push(ethutil.BigD(addr)) } self.Endl() // Debug hook if self.Dbg != nil { self.Dbg.SetCode(closure.Code) } case CALL, CALLCODE: self.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()) var ( ret []byte err error ) if op == CALLCODE { ret, err = self.env.CallCode(closure, addr.Bytes(), args, gas, price, value) } else { ret, err = self.env.Call(closure, addr.Bytes(), args, gas, price, value) } if err != nil { stack.Push(ethutil.BigFalse) vmlogger.Debugln(err) } else { stack.Push(ethutil.BigTrue) msg.Output = ret mem.Set(retOffset.Uint64(), retSize.Uint64(), ret) } self.Printf("resume %x (%v)", closure.Address(), closure.Gas) // Debug hook if self.Dbg != nil { self.Dbg.SetCode(closure.Code) } case RETURN: size, offset := stack.Popn() ret := mem.Get(offset.Int64(), size.Int64()) self.Printf(" => (%d) 0x%x", len(ret), ret).Endl() return closure.Return(ret), nil case SUICIDE: receiver := statedb.GetOrNewStateObject(stack.Pop().Bytes()) balance := statedb.GetBalance(closure.Address()) self.Printf(" => (%x) %v", receiver.Address()[:4], balance) receiver.AddAmount(balance) statedb.Delete(closure.Address()) fallthrough case STOP: // Stop the closure self.Endl() return closure.Return(nil), nil default: vmlogger.Debugf("(pc) %-3v Invalid opcode %x\n", pc, op) closure.ReturnGas(big.NewInt(1), nil) return closure.Return(nil), fmt.Errorf("Invalid opcode %x", op) } pc++ self.Endl() if self.Dbg != nil { for _, instrNo := range self.Dbg.BreakPoints() { if pc == uint64(instrNo) { self.Stepping = true if !self.Dbg.BreakHook(prevStep, op, mem, stack, statedb.GetStateObject(closure.Address())) { return nil, nil } } else if self.Stepping { if !self.Dbg.StepHook(prevStep, op, mem, stack, statedb.GetStateObject(closure.Address())) { return nil, nil } } } } } } func (self *DebugVm) RunPrecompiled(p *PrecompiledAccount, callData []byte, closure *Closure) (ret []byte, err error) { gas := p.Gas(len(callData)) if closure.UseGas(gas) { ret = p.Call(callData) self.Printf("NATIVE_FUNC => %x", ret) self.Endl() return closure.Return(ret), nil } else { self.Endl() tmp := new(big.Int).Set(closure.Gas) closure.UseGas(closure.Gas) return closure.Return(nil), OOG(gas, tmp) } } func (self *DebugVm) Printf(format string, v ...interface{}) VirtualMachine { if self.logTy == LogTyPretty { self.logStr += fmt.Sprintf(format, v...) } return self } func (self *DebugVm) Endl() VirtualMachine { if self.logTy == LogTyPretty { vmlogger.Debugln(self.logStr) self.logStr = "" } return self } func (self *DebugVm) Env() Environment { return self.env }