nimbus-eth1/nimbus/vm/computation.nim

289 lines
9.4 KiB
Nim

# Nimbus
# Copyright (c) 2018 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed except according to those terms.
import
chronicles, strformat, strutils, sequtils, macros, terminal, math, tables, options,
eth/[common, keys], eth/trie/db as triedb,
../constants, ../errors, ../validation, ../vm_state, ../vm_types,
./interpreter/[opcode_values, gas_meter, gas_costs, vm_forks],
./code_stream, ./memory, ./message, ./stack, ../db/[state_db, db_chain],
../utils/header, byteutils, ranges, precompiles,
transaction_tracer
logScope:
topics = "vm computation"
proc newBaseComputation*(vmState: BaseVMState, blockNumber: UInt256, message: Message, forkOverride=none(Fork)): BaseComputation =
new result
result.vmState = vmState
result.msg = message
result.memory = Memory()
result.stack = newStack()
result.gasMeter.init(message.gas)
result.children = @[]
result.accountsToDelete = initTable[EthAddress, EthAddress]()
result.code = newCodeStream(message.code)
# result.rawOutput = "0x"
result.gasCosts =
if forkOverride.isSome:
forkOverride.get.forkToSchedule
else:
blockNumber.toFork.forkToSchedule
result.forkOverride = forkOverride
# a dummy/terminus continuation proc
result.nextProc = proc() =
discard
proc isOriginComputation*(c: BaseComputation): bool =
# Is this computation the computation initiated by a transaction
c.msg.isOrigin
template isSuccess*(c: BaseComputation): bool =
c.error.isNil
template isError*(c: BaseComputation): bool =
not c.isSuccess
func shouldBurnGas*(c: BaseComputation): bool =
c.isError and c.error.burnsGas
func shouldEraseReturnData*(c: BaseComputation): bool =
c.isError and c.error.erasesReturnData
func bytesToHex(x: openarray[byte]): string {.inline.} =
## TODO: use seq[byte] for raw data and delete this proc
foldl(x, a & b.int.toHex(2).toLowerAscii, "0x")
func output*(c: BaseComputation): seq[byte] =
if c.shouldEraseReturnData:
@[]
else:
c.rawOutput
func `output=`*(c: BaseComputation, value: openarray[byte]) =
c.rawOutput = @value
proc outputHex*(c: BaseComputation): string =
if c.shouldEraseReturnData:
return "0x"
c.rawOutput.bytesToHex
proc isSuicided*(c: BaseComputation, address: EthAddress): bool =
result = address in c.accountsToDelete
proc prepareChildMessage*(
c: BaseComputation,
gas: GasInt,
to: EthAddress,
value: UInt256,
data: seq[byte],
code: seq[byte],
options: MessageOptions = newMessageOptions()): Message =
var childOptions = options
childOptions.depth = c.msg.depth + 1
result = newMessage(
gas,
c.msg.gasPrice,
to,
c.msg.origin,
value,
data,
code,
childOptions)
proc snapshot*(comp: BaseComputation) =
comp.dbsnapshot.transaction = comp.vmState.chaindb.db.beginTransaction()
comp.dbsnapshot.intermediateRoot = comp.vmState.accountDb.rootHash
comp.vmState.blockHeader.stateRoot = comp.vmState.accountDb.rootHash
proc revert*(comp: BaseComputation, burnsGas = false) =
comp.dbsnapshot.transaction.rollback()
comp.vmState.accountDb.rootHash = comp.dbsnapshot.intermediateRoot
comp.vmState.blockHeader.stateRoot = comp.dbsnapshot.intermediateRoot
comp.error = Error(info: getCurrentExceptionMsg(), burnsGas: burnsGas)
proc commit*(comp: BaseComputation) =
comp.dbsnapshot.transaction.commit()
comp.vmState.accountDb.rootHash = comp.vmState.blockHeader.stateRoot
proc dispose*(comp: BaseComputation) {.inline.} =
comp.dbsnapshot.transaction.dispose()
proc rollback*(comp: BaseComputation) =
comp.dbsnapshot.transaction.rollback()
comp.vmState.accountDb.rootHash = comp.dbsnapshot.intermediateRoot
comp.vmState.blockHeader.stateRoot = comp.dbsnapshot.intermediateRoot
proc setError*(comp: BaseComputation, msg: string, burnsGas = false) {.inline.} =
comp.error = Error(info: msg, burnsGas: burnsGas)
proc getFork*(computation: BaseComputation): Fork =
result =
if computation.forkOverride.isSome:
computation.forkOverride.get
else:
computation.vmState.blockNumber.toFork
proc writeContract*(computation: BaseComputation, fork: Fork): bool =
result = true
let contractCode = computation.output
if contractCode.len == 0: return
if fork >= FkSpurious and contractCode.len >= EIP170_CODE_SIZE_LIMIT:
debug "Contract code size exceeds EIP170", limit=EIP170_CODE_SIZE_LIMIT, actual=contractCode.len
return false
let storageAddr = computation.msg.storageAddress
if computation.isSuicided(storageAddr): return
let gasParams = GasParams(kind: Create, cr_memLength: contractCode.len)
let codeCost = computation.gasCosts[Create].c_handler(0.u256, gasParams).gasCost
if computation.gasMeter.gasRemaining >= codeCost:
computation.gasMeter.consumeGas(codeCost, reason = "Write contract code for CREATE")
computation.vmState.mutateStateDb:
db.setCode(storageAddr, contractCode.toRange)
result = true
else:
if fork < FkHomestead: computation.output = @[]
result = false
proc transferBalance(computation: BaseComputation, opCode: static[Op]) =
if computation.msg.depth > MaxCallDepth:
computation.setError(&"Stack depth limit reached depth={computation.msg.depth}")
return
let senderBalance = computation.vmState.readOnlyStateDb().
getBalance(computation.msg.sender)
if senderBalance < computation.msg.value:
computation.setError(&"insufficient funds available={senderBalance}, needed={computation.msg.value}")
return
when opCode in {Call, Create}:
computation.vmState.mutateStateDb:
db.subBalance(computation.msg.sender, computation.msg.value)
db.addBalance(computation.msg.storageAddress, computation.msg.value)
template continuation*(comp: BaseComputation, body: untyped) =
# this is a helper template to implement continuation
# passing and convert all recursion into tail call
var tmpNext = comp.nextProc
comp.nextProc = proc() =
body
tmpNext()
proc postExecuteVM(computation: BaseComputation) =
if computation.isSuccess and computation.msg.isCreate:
let fork = computation.getFork
let contractFailed = not computation.writeContract(fork)
if contractFailed and fork == FkHomestead:
computation.setError(&"writeContract failed, depth={computation.msg.depth}", true)
if computation.isSuccess:
computation.commit()
else:
computation.rollback()
proc executeOpcodes*(computation: BaseComputation) {.gcsafe.}
proc applyMessage*(computation: BaseComputation, opCode: static[Op]) =
computation.snapshot()
defer:
computation.dispose()
when opCode in {CallCode, Call, Create}:
computation.transferBalance(opCode)
if computation.isError():
computation.rollback()
computation.nextProc()
return
if computation.gasMeter.gasRemaining < 0:
computation.commit()
computation.nextProc()
return
continuation(computation):
postExecuteVM(computation)
executeOpcodes(computation)
proc addChildComputation*(computation: BaseComputation, child: BaseComputation) =
if child.isError:
if child.msg.isCreate:
computation.returnData = child.output
elif child.shouldBurnGas:
computation.returnData = @[]
else:
computation.returnData = child.output
else:
if child.msg.isCreate:
computation.returnData = @[]
else:
computation.returnData = child.output
for k, v in child.accountsToDelete:
computation.accountsToDelete[k] = v
computation.logEntries.add child.logEntries
if not child.shouldBurnGas:
computation.gasMeter.returnGas(child.gasMeter.gasRemaining)
computation.children.add(child)
proc registerAccountForDeletion*(c: BaseComputation, beneficiary: EthAddress) =
if c.msg.storageAddress in c.accountsToDelete:
raise newException(ValueError,
"invariant: should be impossible for an account to be " &
"registered for deletion multiple times")
c.accountsToDelete[c.msg.storageAddress] = beneficiary
proc addLogEntry*(c: BaseComputation, log: Log) {.inline.} =
c.logEntries.add(log)
# many methods are basically TODO, but they still return valid values
# in order to test some existing code
iterator accountsForDeletion*(c: BaseComputation): EthAddress =
if not c.isError:
for account in c.accountsToDelete.keys:
yield account
proc getGasRefund*(c: BaseComputation): GasInt =
if c.isError:
result = 0
else:
result = c.gasMeter.gasRefunded + c.children.mapIt(it.getGasRefund()).foldl(a + b, 0'i64)
proc getGasUsed*(c: BaseComputation): GasInt =
if c.shouldBurnGas:
result = c.msg.gas
else:
result = max(0, c.msg.gas - c.gasMeter.gasRemaining)
proc getGasRemaining*(c: BaseComputation): GasInt =
if c.shouldBurnGas:
result = 0
else:
result = c.gasMeter.gasRemaining
proc tracingEnabled*(c: BaseComputation): bool =
c.vmState.tracingEnabled
proc traceOpCodeStarted*(c: BaseComputation, op: Op): int =
c.vmState.tracer.traceOpCodeStarted(c, op)
proc traceOpCodeEnded*(c: BaseComputation, op: Op, lastIndex: int) =
c.vmState.tracer.traceOpCodeEnded(c, op, lastIndex)
proc traceError*(c: BaseComputation) =
c.vmState.tracer.traceError(c)
proc prepareTracer*(c: BaseComputation) =
c.vmState.tracer.prepare(c.msg.depth)
include interpreter_dispatch