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state_transition.go
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state_transition.go
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package keeper
import (
"math"
"math/big"
sdk "github.com/cosmos/cosmos-sdk/types"
sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
ethtypes "github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/params"
evmkeeper "github.com/evmos/ethermint/x/evm/keeper"
"github.com/evmos/ethermint/x/evm/statedb"
"github.com/evmos/ethermint/x/evm/types"
)
// ApplyTransaction runs and attempts to perform a state transition with the given transaction (i.e Message), that will
// only be persisted (committed) to the underlying KVStore if the transaction does not fail.
//
// # Gas tracking
//
// Ethereum consumes gas according to the EVM opcodes instead of general reads and writes to store. Because of this, the
// state transition needs to ignore the SDK gas consumption mechanism defined by the GasKVStore and instead consume the
// amount of gas used by the VM execution. The amount of gas used is tracked by the EVM and returned in the execution
// result.
//
// Prior to the execution, the starting tx gas meter is saved and replaced with an infinite gas meter in a new context
// in order to ignore the SDK gas consumption config values (read, write, has, delete).
// After the execution, the gas used from the message execution will be added to the starting gas consumed, taking into
// consideration the amount of gas returned. Finally, the context is updated with the EVM gas consumed value prior to
// returning.
//
// For relevant discussion see: https://github.com/cosmos/cosmos-sdk/discussions/9072
func (k *Keeper) ApplyTransaction(ctx sdk.Context, tx *ethtypes.Transaction) (*types.MsgEthereumTxResponse, error) {
var (
bloom *big.Int
bloomReceipt ethtypes.Bloom
)
cfg, err := k.EVMConfig(ctx)
if err != nil {
return nil, sdkerrors.Wrap(err, "failed to load evm config")
}
txConfig := k.TxConfig(ctx, tx.Hash())
// get the signer according to the chain rules from the config and block height
signer := ethtypes.MakeSigner(cfg.ChainConfig, big.NewInt(ctx.BlockHeight()))
msg, err := tx.AsMessage(signer, cfg.BaseFee)
if err != nil {
return nil, sdkerrors.Wrap(err, "failed to return ethereum transaction as core message")
}
// snapshot to contain the tx processing and post processing in same scope
var commit func()
tmpCtx := ctx
if k.hasHooks {
// Create a cache context to revert state when tx hooks fails,
// the cache context is only committed when both tx and hooks executed successfully.
// Didn't use `Snapshot` because the context stack has exponential complexity on certain operations,
// thus restricted to be used only inside `ApplyMessage`.
tmpCtx, commit = ctx.CacheContext()
}
// pass true to commit the StateDB
res, err := k.ApplyMessageWithConfig(tmpCtx, msg, nil, true, cfg, txConfig)
if err != nil {
return nil, sdkerrors.Wrap(err, "failed to apply ethereum core message")
}
logs := types.LogsToEthereum(res.Logs)
// Compute block bloom filter
if len(logs) > 0 {
bloom = k.GetBlockBloomTransient(ctx)
bloom.Or(bloom, big.NewInt(0).SetBytes(ethtypes.LogsBloom(logs)))
bloomReceipt = ethtypes.BytesToBloom(bloom.Bytes())
}
cumulativeGasUsed := res.GasUsed
if ctx.BlockGasMeter() != nil {
limit := ctx.BlockGasMeter().Limit()
consumed := ctx.BlockGasMeter().GasConsumed()
cumulativeGasUsed = uint64(math.Min(float64(cumulativeGasUsed+consumed), float64(limit)))
}
var contractAddr common.Address
if msg.To() == nil {
contractAddr = crypto.CreateAddress(msg.From(), msg.Nonce())
}
receipt := ðtypes.Receipt{
Type: tx.Type(),
PostState: nil, // TODO: intermediate state root
CumulativeGasUsed: cumulativeGasUsed,
Bloom: bloomReceipt,
Logs: logs,
TxHash: txConfig.TxHash,
ContractAddress: contractAddr,
GasUsed: res.GasUsed,
BlockHash: txConfig.BlockHash,
BlockNumber: big.NewInt(ctx.BlockHeight()),
TransactionIndex: txConfig.TxIndex,
}
if !res.Failed() {
receipt.Status = ethtypes.ReceiptStatusSuccessful
// Only call hooks if tx executed successfully.
if err = k.PostTxProcessing(tmpCtx, msg, receipt); err != nil {
// If hooks return error, revert the whole tx.
res.VmError = types.ErrPostTxProcessing.Error()
k.Logger(ctx).Error("tx post processing failed", "error", err)
// If the tx failed in post processing hooks, we should clear the logs
res.Logs = nil
} else if commit != nil {
// PostTxProcessing is successful, commit the tmpCtx
commit()
// Since the post processing can alter the log, we need to update the result
res.Logs = types.NewLogsFromEth(receipt.Logs)
ctx.EventManager().EmitEvents(tmpCtx.EventManager().Events())
}
}
// refund gas in order to match the Ethereum gas consumption instead of the default SDK one.
if err = k.RefundGas(ctx, msg, msg.Gas()-res.GasUsed, cfg.Params.EvmDenom); err != nil {
return nil, sdkerrors.Wrapf(err, "failed to refund gas leftover gas to sender %s", msg.From())
}
if len(receipt.Logs) > 0 {
// Update transient block bloom filter
k.SetBlockBloomTransient(ctx, receipt.Bloom.Big())
k.SetLogSizeTransient(ctx, uint64(txConfig.LogIndex)+uint64(len(receipt.Logs)))
}
k.SetTxIndexTransient(ctx, uint64(txConfig.TxIndex)+1)
totalGasUsed, err := k.AddTransientGasUsed(ctx, res.GasUsed)
if err != nil {
return nil, sdkerrors.Wrap(err, "failed to add transient gas used")
}
// reset the gas meter for current cosmos transaction
k.ResetGasMeterAndConsumeGas(ctx, totalGasUsed)
return res, nil
}
// ApplyMessageWithConfig computes the new state by applying the given message against the existing state.
// If the message fails, the VM execution error with the reason will be returned to the client
// and the transaction won't be committed to the store.
//
// # Reverted state
//
// The snapshot and rollback are supported by the `statedb.StateDB`.
//
// # Different Callers
//
// It's called in three scenarios:
// 1. `ApplyTransaction`, in the transaction processing flow.
// 2. `EthCall/EthEstimateGas` grpc query handler.
// 3. Called by other native modules directly.
//
// # Prechecks and Preprocessing
//
// All relevant state transition prechecks for the MsgEthereumTx are performed on the AnteHandler,
// prior to running the transaction against the state. The prechecks run are the following:
//
// 1. the nonce of the message caller is correct
// 2. caller has enough balance to cover transaction fee(gaslimit * gasprice)
// 3. the amount of gas required is available in the block
// 4. the purchased gas is enough to cover intrinsic usage
// 5. there is no overflow when calculating intrinsic gas
// 6. caller has enough balance to cover asset transfer for **topmost** call
//
// The preprocessing steps performed by the AnteHandler are:
//
// 1. set up the initial access list (iff fork > Berlin)
//
// # Tracer parameter
//
// It should be a `vm.Tracer` object or nil, if pass `nil`, it'll create a default one based on keeper options.
//
// # Commit parameter
//
// If commit is true, the `StateDB` will be committed, otherwise discarded.
func (k *Keeper) ApplyMessageWithConfig(ctx sdk.Context, msg core.Message, tracer vm.EVMLogger, commit bool, cfg *types.EVMConfig, txConfig statedb.TxConfig) (*types.MsgEthereumTxResponse, error) {
var (
ret []byte // return bytes from evm execution
vmErr error // vm errors do not effect consensus and are therefore not assigned to err
)
// return error if contract creation or call are disabled through governance
if !cfg.Params.EnableCreate && msg.To() == nil {
return nil, sdkerrors.Wrap(types.ErrCreateDisabled, "failed to create new contract")
} else if !cfg.Params.EnableCall && msg.To() != nil {
return nil, sdkerrors.Wrap(types.ErrCallDisabled, "failed to call contract")
}
stateDB := statedb.New(ctx, k, txConfig)
evm := k.NewEVM(ctx, msg, cfg, tracer, stateDB)
leftoverGas := msg.Gas()
// Allow the tracer captures the tx level events, mainly the gas consumption.
if evm.Config.Debug {
evm.Config.Tracer.CaptureTxStart(leftoverGas)
defer func() {
evm.Config.Tracer.CaptureTxEnd(leftoverGas)
}()
}
sender := vm.AccountRef(msg.From())
contractCreation := msg.To() == nil
isLondon := cfg.ChainConfig.IsLondon(evm.Context.BlockNumber)
intrinsicGas, err := k.GetEthIntrinsicGas(ctx, msg, cfg.ChainConfig, contractCreation)
if err != nil {
// should have already been checked on Ante Handler
return nil, sdkerrors.Wrap(err, "intrinsic gas failed")
}
// Should check again even if it is checked on Ante Handler, because eth_call don't go through Ante Handler.
if leftoverGas < intrinsicGas {
// eth_estimateGas will check for this exact error
return nil, sdkerrors.Wrap(core.ErrIntrinsicGas, "apply message")
}
leftoverGas -= intrinsicGas
// access list preparation is moved from ante handler to here, because it's needed when `ApplyMessage` is called
// under contexts where ante handlers are not run, for example `eth_call` and `eth_estimateGas`.
if rules := cfg.ChainConfig.Rules(big.NewInt(ctx.BlockHeight()), cfg.ChainConfig.MergeNetsplitBlock != nil); rules.IsBerlin {
stateDB.PrepareAccessList(msg.From(), msg.To(), vm.ActivePrecompiles(rules), msg.AccessList())
}
if contractCreation {
// take over the nonce management from evm:
// - reset sender's nonce to msg.Nonce() before calling evm.
// - increase sender's nonce by one no matter the result.
stateDB.SetNonce(sender.Address(), msg.Nonce())
ret, _, leftoverGas, vmErr = evm.Create(sender, msg.Data(), leftoverGas, msg.Value())
stateDB.SetNonce(sender.Address(), msg.Nonce()+1)
} else {
ret, leftoverGas, vmErr = evm.Call(sender, *msg.To(), msg.Data(), leftoverGas, msg.Value())
}
refundQuotient := params.RefundQuotient
// After EIP-3529: refunds are capped to gasUsed / 5
if isLondon {
refundQuotient = params.RefundQuotientEIP3529
}
// calculate gas refund
if msg.Gas() < leftoverGas {
return nil, sdkerrors.Wrap(types.ErrGasOverflow, "apply message")
}
// refund gas
leftoverGas += evmkeeper.GasToRefund(stateDB.GetRefund(), msg.Gas()-leftoverGas, refundQuotient)
// EVM execution error needs to be available for the JSON-RPC client
var vmError string
if vmErr != nil {
vmError = vmErr.Error()
}
// The dirty states in `StateDB` is either committed or discarded after return
if commit {
if err := stateDB.Commit(); err != nil {
return nil, sdkerrors.Wrap(err, "failed to commit stateDB")
}
}
// calculate a minimum amount of gas to be charged to sender if GasLimit
// is considerably higher than GasUsed to stay more aligned with Tendermint gas mechanics
// for more info https://github.com/evmos/ethermint/issues/1085
gasLimit := sdk.NewDec(int64(msg.Gas()))
minGasMultiplier := k.GetMinGasMultiplier(ctx)
minimumGasUsed := gasLimit.Mul(minGasMultiplier)
if msg.Gas() < leftoverGas {
return nil, sdkerrors.Wrapf(types.ErrGasOverflow, "message gas limit < leftover gas (%d < %d)", msg.Gas(), leftoverGas)
}
temporaryGasUsed := msg.Gas() - leftoverGas
gasUsed := sdk.MaxDec(minimumGasUsed, sdk.NewDec(int64(temporaryGasUsed))).TruncateInt().Uint64()
// reset leftoverGas, to be used by the tracer
leftoverGas = msg.Gas() - gasUsed
return &types.MsgEthereumTxResponse{
GasUsed: gasUsed,
VmError: vmError,
Ret: ret,
Logs: types.NewLogsFromEth(stateDB.Logs()),
Hash: txConfig.TxHash.Hex(),
}, nil
}
// ApplyMessage calls ApplyMessageWithConfig with default EVMConfig
func (k *Keeper) ApplyMessage(ctx sdk.Context, msg core.Message, tracer vm.EVMLogger, commit bool) (*types.MsgEthereumTxResponse, error) {
cfg, err := k.EVMConfig(ctx)
if err != nil {
return nil, sdkerrors.Wrap(err, "failed to load evm config")
}
txConfig := statedb.NewEmptyTxConfig(common.BytesToHash(ctx.HeaderHash()))
return k.ApplyMessageWithConfig(ctx, msg, tracer, commit, cfg, txConfig)
}