private UserOperationSimulationResult SimulateValidation(
Transaction transaction,
UserOperation userOperation,
BlockHeader parent,
ITransactionProcessor transactionProcessor)
{
bool paymasterWhitelisted = _whitelistedPaymasters.Contains(userOperation.Paymaster);
UserOperationTxTracer txTracer = new(
transaction,
paymasterWhitelisted,
userOperation.InitCode != Bytes.Empty, userOperation.Sender,
userOperation.Paymaster,
_entryPointContractAddress,
_logger
);
transactionProcessor.Trace(transaction, parent, txTracer);
FailedOp?failedOp = _userOperationTxBuilder.DecodeEntryPointOutputError(txTracer.Output);
string?error = null;
if (!txTracer.Success)
{
if (failedOp is not null)
{
error = failedOp.ToString() !;
}
else
{
error = txTracer.Error;
}
return(UserOperationSimulationResult.Failed(error));
}
UserOperationAccessList userOperationAccessList = new(txTracer.AccessedStorage);
IDictionary <Address, Keccak> addressesToCodeHashes = new Dictionary <Address, Keccak>();
foreach (Address accessedAddress in txTracer.AccessedAddresses)
{
addressesToCodeHashes[accessedAddress] = _stateProvider.GetCodeHash(accessedAddress);
}
return(new UserOperationSimulationResult()
{
Success = true,
AccessList = userOperationAccessList,
AddressesToCodeHashes = addressesToCodeHashes,
Error = error
});
}
public ResultWrapper <Keccak> Simulate(UserOperation userOperation,
BlockHeader parent,
UInt256?timestamp = null,
CancellationToken cancellationToken = default)
{
if (userOperation.AlreadySimulated)
{
// codehash of all accessed addresses should not change between calls
foreach (KeyValuePair <Address, Keccak> kv in userOperation.AddressesToCodeHashes)
{
(Address address, Keccak expectedCodeHash) = kv;
Keccak codeHash = _stateProvider.GetCodeHash(address);
if (codeHash != expectedCodeHash)
{
return(ResultWrapper <Keccak> .Fail($"codehash of address {address} changed since initial simulation"));
}
}
}
IReleaseSpec currentSpec = _specProvider.GetSpec(parent.Number + 1);
ReadOnlyTxProcessingEnv txProcessingEnv = _readOnlyTxProcessingEnvFactory.Create();
ITransactionProcessor transactionProcessor = txProcessingEnv.Build(_stateProvider.StateRoot);
// wrap userOp into a tx calling the simulateWallet function off-chain from zero-address (look at EntryPoint.sol for more context)
Transaction simulateValidationTransaction =
BuildSimulateValidationTransaction(userOperation, parent, currentSpec);
UserOperationSimulationResult simulationResult = SimulateValidation(simulateValidationTransaction, userOperation, parent, transactionProcessor);
if (!simulationResult.Success)
{
return(ResultWrapper <Keccak> .Fail(simulationResult.Error ?? "unknown simulation failure"));
}
if (userOperation.AlreadySimulated)
{
// if previously simulated we must make sure it doesn't access any more than it did on the first round
if (!userOperation.AccessList.AccessListContains(simulationResult.AccessList.Data))
{
return(ResultWrapper <Keccak> .Fail("access list exceeded"));
}
}
else
{
userOperation.AccessList = simulationResult.AccessList;
userOperation.AddressesToCodeHashes = simulationResult.AddressesToCodeHashes;
userOperation.AlreadySimulated = true;
}
return(ResultWrapper <Keccak> .Success(userOperation.RequestId !));
}
