// Copyright 2014 The go-ethereum Authors // This file is part of the go-ethereum library. // // The go-ethereum library is free software: you can redistribute it and/or modify // it under the terms of the GNU Lesser General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // The go-ethereum library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public License // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. // Package state provides a caching layer atop the Ethereum state trie. package state import ( "errors" "fmt" "math/big" "sort" "time" "github.com/ava-labs/coreth/core/types" "github.com/ava-labs/go-ethereum/common" "github.com/ava-labs/go-ethereum/crypto" "github.com/ava-labs/go-ethereum/log" "github.com/ava-labs/go-ethereum/metrics" "github.com/ava-labs/go-ethereum/rlp" "github.com/ava-labs/go-ethereum/trie" ) type revision struct { id int journalIndex int } var ( // emptyRoot is the known root hash of an empty trie. emptyRoot = common.HexToHash("56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421") zeroRoot = common.HexToHash("0000000000000000000000000000000000000000000000000000000000000000") // emptyCode is the known hash of the empty EVM bytecode. emptyCode = crypto.Keccak256Hash(nil) ) type proofList [][]byte func (n *proofList) Put(key []byte, value []byte) error { *n = append(*n, value) return nil } func (n *proofList) Delete(key []byte) error { panic("not supported") } // StateDBs within the ethereum protocol are used to store anything // within the merkle trie. StateDBs take care of caching and storing // nested states. It's the general query interface to retrieve: // * Contracts // * Accounts type StateDB struct { db Database trie Trie // This map holds 'live' objects, which will get modified while processing a state transition. stateObjects map[common.Address]*stateObject stateObjectsDirty map[common.Address]struct{} // DB error. // State objects are used by the consensus core and VM which are // unable to deal with database-level errors. Any error that occurs // during a database read is memoized here and will eventually be returned // by StateDB.Commit. dbErr error // The refund counter, also used by state transitioning. refund uint64 thash, bhash common.Hash txIndex int logs map[common.Hash][]*types.Log logSize uint preimages map[common.Hash][]byte // Journal of state modifications. This is the backbone of // Snapshot and RevertToSnapshot. journal *journal validRevisions []revision nextRevisionId int // Measurements gathered during execution for debugging purposes AccountReads time.Duration AccountHashes time.Duration AccountUpdates time.Duration AccountCommits time.Duration StorageReads time.Duration StorageHashes time.Duration StorageUpdates time.Duration StorageCommits time.Duration } // Create a new state from a given trie. func New(root common.Hash, db Database) (*StateDB, error) { tr, err := db.OpenTrie(root) if err != nil { return nil, err } return &StateDB{ db: db, trie: tr, stateObjects: make(map[common.Address]*stateObject), stateObjectsDirty: make(map[common.Address]struct{}), logs: make(map[common.Hash][]*types.Log), preimages: make(map[common.Hash][]byte), journal: newJournal(), }, nil } // setError remembers the first non-nil error it is called with. func (self *StateDB) setError(err error) { if self.dbErr == nil { self.dbErr = err } } func (self *StateDB) Error() error { return self.dbErr } // Reset clears out all ephemeral state objects from the state db, but keeps // the underlying state trie to avoid reloading data for the next operations. func (self *StateDB) Reset(root common.Hash) error { tr, err := self.db.OpenTrie(root) if err != nil { return err } self.trie = tr self.stateObjects = make(map[common.Address]*stateObject) self.stateObjectsDirty = make(map[common.Address]struct{}) self.thash = common.Hash{} self.bhash = common.Hash{} self.txIndex = 0 self.logs = make(map[common.Hash][]*types.Log) self.logSize = 0 self.preimages = make(map[common.Hash][]byte) self.clearJournalAndRefund() return nil } func (self *StateDB) AddLog(log *types.Log) { self.journal.append(addLogChange{txhash: self.thash}) log.TxHash = self.thash log.BlockHash = self.bhash log.TxIndex = uint(self.txIndex) log.Index = self.logSize self.logs[self.thash] = append(self.logs[self.thash], log) self.logSize++ } func (self *StateDB) GetLogs(hash common.Hash) []*types.Log { return self.logs[hash] } func (self *StateDB) Logs() []*types.Log { var logs []*types.Log for _, lgs := range self.logs { logs = append(logs, lgs...) } return logs } // AddPreimage records a SHA3 preimage seen by the VM. func (self *StateDB) AddPreimage(hash common.Hash, preimage []byte) { if _, ok := self.preimages[hash]; !ok { self.journal.append(addPreimageChange{hash: hash}) pi := make([]byte, len(preimage)) copy(pi, preimage) self.preimages[hash] = pi } } // Preimages returns a list of SHA3 preimages that have been submitted. func (self *StateDB) Preimages() map[common.Hash][]byte { return self.preimages } // AddRefund adds gas to the refund counter func (self *StateDB) AddRefund(gas uint64) { self.journal.append(refundChange{prev: self.refund}) self.refund += gas } // SubRefund removes gas from the refund counter. // This method will panic if the refund counter goes below zero func (self *StateDB) SubRefund(gas uint64) { self.journal.append(refundChange{prev: self.refund}) if gas > self.refund { panic("Refund counter below zero") } self.refund -= gas } // Exist reports whether the given account address exists in the state. // Notably this also returns true for suicided accounts. func (self *StateDB) Exist(addr common.Address) bool { return self.getStateObject(addr) != nil } // Empty returns whether the state object is either non-existent // or empty according to the EIP161 specification (balance = nonce = code = 0) func (self *StateDB) Empty(addr common.Address) bool { so := self.getStateObject(addr) return so == nil || so.empty() } // Retrieve the balance from the given address or 0 if object not found func (self *StateDB) GetBalance(addr common.Address) *big.Int { stateObject := self.getStateObject(addr) if stateObject != nil { return stateObject.Balance() } return common.Big0 } // Retrieve the balance from the given address or 0 if object not found func (self *StateDB) GetBalanceMultiCoin(addr common.Address, coinID common.Hash) *big.Int { stateObject := self.getStateObject(addr) if stateObject != nil { return stateObject.BalanceMultiCoin(coinID, self.db) } return common.Big0 } func (self *StateDB) EnableMultiCoin(addr common.Address) error { stateObject := self.GetOrNewStateObject(addr) if stateObject.data.Root != emptyRoot && stateObject.data.Root != zeroRoot { return errors.New("not a fresh account") } if !stateObject.EnableMultiCoin() { return errors.New("multi-coin mode already enabled") } return nil } func (self *StateDB) ForceEnableMultiCoin(addr common.Address) { stateObject := self.GetOrNewStateObject(addr) stateObject.EnableMultiCoin() } func (self *StateDB) IsMultiCoin(addr common.Address) bool { stateObject := self.getStateObject(addr) if stateObject != nil { return stateObject.IsMultiCoin() } return false } func (self *StateDB) GetNonce(addr common.Address) uint64 { stateObject := self.getStateObject(addr) if stateObject != nil { return stateObject.Nonce() } return 0 } // TxIndex returns the current transaction index set by Prepare. func (self *StateDB) TxIndex() int { return self.txIndex } // BlockHash returns the current block hash set by Prepare. func (self *StateDB) BlockHash() common.Hash { return self.bhash } func (self *StateDB) GetCode(addr common.Address) []byte { stateObject := self.getStateObject(addr) if stateObject != nil { return stateObject.Code(self.db) } return nil } func (self *StateDB) GetCodeSize(addr common.Address) int { stateObject := self.getStateObject(addr) if stateObject == nil { return 0 } if stateObject.code != nil { return len(stateObject.code) } size, err := self.db.ContractCodeSize(stateObject.addrHash, common.BytesToHash(stateObject.CodeHash())) if err != nil { self.setError(err) } return size } func (self *StateDB) GetCodeHash(addr common.Address) common.Hash { stateObject := self.getStateObject(addr) if stateObject == nil { return common.Hash{} } return common.BytesToHash(stateObject.CodeHash()) } // GetState retrieves a value from the given account's storage trie. func (self *StateDB) GetState(addr common.Address, hash common.Hash) common.Hash { stateObject := self.getStateObject(addr) if stateObject != nil { return stateObject.GetState(self.db, hash) } return common.Hash{} } // GetProof returns the MerkleProof for a given Account func (self *StateDB) GetProof(a common.Address) ([][]byte, error) { var proof proofList err := self.trie.Prove(crypto.Keccak256(a.Bytes()), 0, &proof) return [][]byte(proof), err } // GetProof returns the StorageProof for given key func (self *StateDB) GetStorageProof(a common.Address, key common.Hash) ([][]byte, error) { var proof proofList trie := self.StorageTrie(a) if trie == nil { return proof, errors.New("storage trie for requested address does not exist") } err := trie.Prove(crypto.Keccak256(key.Bytes()), 0, &proof) return [][]byte(proof), err } // GetCommittedState retrieves a value from the given account's committed storage trie. func (self *StateDB) GetCommittedState(addr common.Address, hash common.Hash) common.Hash { stateObject := self.getStateObject(addr) if stateObject != nil { return stateObject.GetCommittedState(self.db, hash) } return common.Hash{} } // Database retrieves the low level database supporting the lower level trie ops. func (self *StateDB) Database() Database { return self.db } // StorageTrie returns the storage trie of an account. // The return value is a copy and is nil for non-existent accounts. func (self *StateDB) StorageTrie(addr common.Address) Trie { stateObject := self.getStateObject(addr) if stateObject == nil { return nil } cpy := stateObject.deepCopy(self) return cpy.updateTrie(self.db) } func (self *StateDB) HasSuicided(addr common.Address) bool { stateObject := self.getStateObject(addr) if stateObject != nil { return stateObject.suicided } return false } /* * SETTERS */ // AddBalance adds amount to the account associated with addr. func (self *StateDB) AddBalance(addr common.Address, amount *big.Int) { stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { stateObject.AddBalance(amount) } } // SubBalance subtracts amount from the account associated with addr. func (self *StateDB) SubBalance(addr common.Address, amount *big.Int) { stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SubBalance(amount) } } func (self *StateDB) SetBalance(addr common.Address, amount *big.Int) { stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SetBalance(amount) } } // AddBalance adds amount to the account associated with addr. func (self *StateDB) AddBalanceMultiCoin(addr common.Address, coinID common.Hash, amount *big.Int) { stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { stateObject.AddBalanceMultiCoin(coinID, amount, self.db) } } // SubBalance subtracts amount from the account associated with addr. func (self *StateDB) SubBalanceMultiCoin(addr common.Address, coinID common.Hash, amount *big.Int) { stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SubBalanceMultiCoin(coinID, amount, self.db) } } func (self *StateDB) SetBalanceMultiCoin(addr common.Address, coinID common.Hash, amount *big.Int) { stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SetBalanceMultiCoin(coinID, amount, self.db) } } func (self *StateDB) SetNonce(addr common.Address, nonce uint64) { stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SetNonce(nonce) } } func (self *StateDB) SetCode(addr common.Address, code []byte) { stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SetCode(crypto.Keccak256Hash(code), code) } } func (self *StateDB) SetState(addr common.Address, key, value common.Hash) (res error) { res = nil stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { if stateObject.data.IsMultiCoin { NormalizeStateKey(&key) } stateObject.SetState(self.db, key, value) } return } // SetStorage replaces the entire storage for the specified account with given // storage. This function should only be used for debugging. func (self *StateDB) SetStorage(addr common.Address, storage map[common.Hash]common.Hash) { stateObject := self.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SetStorage(storage) } } // Suicide marks the given account as suicided. // This clears the account balance. // // The account's state object is still available until the state is committed, // getStateObject will return a non-nil account after Suicide. func (self *StateDB) Suicide(addr common.Address) bool { stateObject := self.getStateObject(addr) if stateObject == nil { return false } self.journal.append(suicideChange{ account: &addr, prev: stateObject.suicided, prevbalance: new(big.Int).Set(stateObject.Balance()), }) stateObject.markSuicided() stateObject.data.Balance = new(big.Int) return true } // // Setting, updating & deleting state object methods. // // updateStateObject writes the given object to the trie. func (s *StateDB) updateStateObject(stateObject *stateObject) { // Track the amount of time wasted on updating the account from the trie if metrics.EnabledExpensive { defer func(start time.Time) { s.AccountUpdates += time.Since(start) }(time.Now()) } // Encode the account and update the account trie addr := stateObject.Address() data, err := rlp.EncodeToBytes(stateObject) if err != nil { panic(fmt.Errorf("can't encode object at %x: %v", addr[:], err)) } s.setError(s.trie.TryUpdate(addr[:], data)) } // deleteStateObject removes the given object from the state trie. func (s *StateDB) deleteStateObject(stateObject *stateObject) { // Track the amount of time wasted on deleting the account from the trie if metrics.EnabledExpensive { defer func(start time.Time) { s.AccountUpdates += time.Since(start) }(time.Now()) } // Delete the account from the trie stateObject.deleted = true addr := stateObject.Address() s.setError(s.trie.TryDelete(addr[:])) } // Retrieve a state object given by the address. Returns nil if not found. func (s *StateDB) getStateObject(addr common.Address) (stateObject *stateObject) { // Prefer live objects if obj := s.stateObjects[addr]; obj != nil { if obj.deleted { return nil } return obj } // Track the amount of time wasted on loading the object from the database if metrics.EnabledExpensive { defer func(start time.Time) { s.AccountReads += time.Since(start) }(time.Now()) } // Load the object from the database enc, err := s.trie.TryGet(addr[:]) if len(enc) == 0 { s.setError(err) return nil } var data Account if err := rlp.DecodeBytes(enc, &data); err != nil { log.Error("Failed to decode state object", "addr", addr, "err", err) return nil } // Insert into the live set obj := newObject(s, addr, data) s.setStateObject(obj) return obj } func (self *StateDB) setStateObject(object *stateObject) { self.stateObjects[object.Address()] = object } // Retrieve a state object or create a new state object if nil. func (self *StateDB) GetOrNewStateObject(addr common.Address) *stateObject { stateObject := self.getStateObject(addr) if stateObject == nil || stateObject.deleted { stateObject, _ = self.createObject(addr) } return stateObject } // createObject creates a new state object. If there is an existing account with // the given address, it is overwritten and returned as the second return value. func (self *StateDB) createObject(addr common.Address) (newobj, prev *stateObject) { prev = self.getStateObject(addr) newobj = newObject(self, addr, Account{}) newobj.setNonce(0) // sets the object to dirty if prev == nil { self.journal.append(createObjectChange{account: &addr}) } else { self.journal.append(resetObjectChange{prev: prev}) } self.setStateObject(newobj) return newobj, prev } // CreateAccount explicitly creates a state object. If a state object with the address // already exists the balance is carried over to the new account. // // CreateAccount is called during the EVM CREATE operation. The situation might arise that // a contract does the following: // // 1. sends funds to sha(account ++ (nonce + 1)) // 2. tx_create(sha(account ++ nonce)) (note that this gets the address of 1) // // Carrying over the balance ensures that Ether doesn't disappear. func (self *StateDB) CreateAccount(addr common.Address) { newObj, prev := self.createObject(addr) if prev != nil { newObj.setBalance(prev.data.Balance) } } func (db *StateDB) ForEachStorage(addr common.Address, cb func(key, value common.Hash) bool) error { so := db.getStateObject(addr) if so == nil { return nil } it := trie.NewIterator(so.getTrie(db.db).NodeIterator(nil)) for it.Next() { key := common.BytesToHash(db.trie.GetKey(it.Key)) if value, dirty := so.dirtyStorage[key]; dirty { if !cb(key, value) { return nil } continue } if len(it.Value) > 0 { _, content, _, err := rlp.Split(it.Value) if err != nil { return err } if !cb(key, common.BytesToHash(content)) { return nil } } } return nil } // Copy creates a deep, independent copy of the state. // Snapshots of the copied state cannot be applied to the copy. func (self *StateDB) Copy() *StateDB { // Copy all the basic fields, initialize the memory ones state := &StateDB{ db: self.db, trie: self.db.CopyTrie(self.trie), stateObjects: make(map[common.Address]*stateObject, len(self.journal.dirties)), stateObjectsDirty: make(map[common.Address]struct{}, len(self.journal.dirties)), refund: self.refund, logs: make(map[common.Hash][]*types.Log, len(self.logs)), logSize: self.logSize, preimages: make(map[common.Hash][]byte, len(self.preimages)), journal: newJournal(), } // Copy the dirty states, logs, and preimages for addr := range self.journal.dirties { // As documented [here](https://github.com/ethereum/go-ethereum/pull/16485#issuecomment-380438527), // and in the Finalise-method, there is a case where an object is in the journal but not // in the stateObjects: OOG after touch on ripeMD prior to Byzantium. Thus, we need to check for // nil if object, exist := self.stateObjects[addr]; exist { state.stateObjects[addr] = object.deepCopy(state) state.stateObjectsDirty[addr] = struct{}{} } } // Above, we don't copy the actual journal. This means that if the copy is copied, the // loop above will be a no-op, since the copy's journal is empty. // Thus, here we iterate over stateObjects, to enable copies of copies for addr := range self.stateObjectsDirty { if _, exist := state.stateObjects[addr]; !exist { state.stateObjects[addr] = self.stateObjects[addr].deepCopy(state) state.stateObjectsDirty[addr] = struct{}{} } } for hash, logs := range self.logs { cpy := make([]*types.Log, len(logs)) for i, l := range logs { cpy[i] = new(types.Log) *cpy[i] = *l } state.logs[hash] = cpy } for hash, preimage := range self.preimages { state.preimages[hash] = preimage } return state } // Snapshot returns an identifier for the current revision of the state. func (self *StateDB) Snapshot() int { id := self.nextRevisionId self.nextRevisionId++ self.validRevisions = append(self.validRevisions, revision{id, self.journal.length()}) return id } // RevertToSnapshot reverts all state changes made since the given revision. func (self *StateDB) RevertToSnapshot(revid int) { // Find the snapshot in the stack of valid snapshots. idx := sort.Search(len(self.validRevisions), func(i int) bool { return self.validRevisions[i].id >= revid }) if idx == len(self.validRevisions) || self.validRevisions[idx].id != revid { panic(fmt.Errorf("revision id %v cannot be reverted", revid)) } snapshot := self.validRevisions[idx].journalIndex // Replay the journal to undo changes and remove invalidated snapshots self.journal.revert(self, snapshot) self.validRevisions = self.validRevisions[:idx] } // GetRefund returns the current value of the refund counter. func (self *StateDB) GetRefund() uint64 { return self.refund } // Finalise finalises the state by removing the self destructed objects // and clears the journal as well as the refunds. func (s *StateDB) Finalise(deleteEmptyObjects bool) { for addr := range s.journal.dirties { stateObject, exist := s.stateObjects[addr] if !exist { // ripeMD is 'touched' at block 1714175, in tx 0x1237f737031e40bcde4a8b7e717b2d15e3ecadfe49bb1bbc71ee9deb09c6fcf2 // That tx goes out of gas, and although the notion of 'touched' does not exist there, the // touch-event will still be recorded in the journal. Since ripeMD is a special snowflake, // it will persist in the journal even though the journal is reverted. In this special circumstance, // it may exist in `s.journal.dirties` but not in `s.stateObjects`. // Thus, we can safely ignore it here continue } if stateObject.suicided || (deleteEmptyObjects && stateObject.empty()) { s.deleteStateObject(stateObject) } else { stateObject.updateRoot(s.db) s.updateStateObject(stateObject) } s.stateObjectsDirty[addr] = struct{}{} } // Invalidate journal because reverting across transactions is not allowed. s.clearJournalAndRefund() } // IntermediateRoot computes the current root hash of the state trie. // It is called in between transactions to get the root hash that // goes into transaction receipts. func (s *StateDB) IntermediateRoot(deleteEmptyObjects bool) common.Hash { s.Finalise(deleteEmptyObjects) // Track the amount of time wasted on hashing the account trie if metrics.EnabledExpensive { defer func(start time.Time) { s.AccountHashes += time.Since(start) }(time.Now()) } return s.trie.Hash() } // Prepare sets the current transaction hash and index and block hash which is // used when the EVM emits new state logs. func (self *StateDB) Prepare(thash, bhash common.Hash, ti int) { self.thash = thash self.bhash = bhash self.txIndex = ti } func (s *StateDB) clearJournalAndRefund() { s.journal = newJournal() s.validRevisions = s.validRevisions[:0] s.refund = 0 } // Commit writes the state to the underlying in-memory trie database. func (s *StateDB) Commit(deleteEmptyObjects bool) (root common.Hash, err error) { defer s.clearJournalAndRefund() for addr := range s.journal.dirties { s.stateObjectsDirty[addr] = struct{}{} } // Commit objects to the trie, measuring the elapsed time for addr, stateObject := range s.stateObjects { _, isDirty := s.stateObjectsDirty[addr] switch { case stateObject.suicided || (isDirty && deleteEmptyObjects && stateObject.empty()): // If the object has been removed, don't bother syncing it // and just mark it for deletion in the trie. s.deleteStateObject(stateObject) case isDirty: // Write any contract code associated with the state object if stateObject.code != nil && stateObject.dirtyCode { s.db.TrieDB().InsertBlob(common.BytesToHash(stateObject.CodeHash()), stateObject.code) stateObject.dirtyCode = false } // Write any storage changes in the state object to its storage trie. if err := stateObject.CommitTrie(s.db); err != nil { return common.Hash{}, err } // Update the object in the main account trie. s.updateStateObject(stateObject) } delete(s.stateObjectsDirty, addr) } // Write the account trie changes, measuing the amount of wasted time if metrics.EnabledExpensive { defer func(start time.Time) { s.AccountCommits += time.Since(start) }(time.Now()) } root, err = s.trie.Commit(func(leaf []byte, parent common.Hash) error { var account Account if err := rlp.DecodeBytes(leaf, &account); err != nil { return nil } if account.Root != emptyRoot { s.db.TrieDB().Reference(account.Root, parent) } code := common.BytesToHash(account.CodeHash) if code != emptyCode { s.db.TrieDB().Reference(code, parent) } return nil }) return root, err }