func (self *StateObject) GetState(key common.Hash) common.Hash {
strkey := key.Str()
value, exists := self.storage[strkey]
if !exists {
value = self.getAddr(key)
if (value != common.Hash{}) {
self.storage[strkey] = value
}
}
return value
}
// HashToHash(key) resolves contenthash for key (a hash) using HashReg
// resolution is costless non-transactional
// implemented as direct retrieval from db
func (self *Registrar) HashToHash(khash common.Hash) (chash common.Hash, err error) {
// look up in hashReg
at := HashRegAddr[2:]
key := storageAddress(storageMapping(storageIdx2Addr(1), khash[:]))
hash := self.backend.StorageAt(at, key)
if hash == "0x0" || len(hash) < 3 || (hash == common.Hash{}.Hex()) {
err = fmt.Errorf("content hash not found for '%v'", khash.Hex())
return
}
copy(chash[:], common.Hex2BytesFixed(hash[2:], 32))
return
}
func (self *XEth) doSign(from common.Address, hash common.Hash, didUnlock bool) ([]byte, error) {
sig, err := self.backend.AccountManager().Sign(accounts.Account{Address: from}, hash.Bytes())
if err == accounts.ErrLocked {
if didUnlock {
return nil, fmt.Errorf("signer account still locked after successful unlock")
}
if !self.frontend.UnlockAccount(from.Bytes()) {
return nil, fmt.Errorf("could not unlock signer account")
}
// retry signing, the account should now be unlocked.
return self.doSign(from, hash, true)
} else if err != nil {
return nil, err
}
return sig, nil
}
// HashToUrl(contenthash) resolves the url for contenthash using UrlHint
// resolution is costless non-transactional
// implemented as direct retrieval from db
// if we use content addressed storage, this step is no longer necessary
func (self *Registrar) HashToUrl(chash common.Hash) (uri string, err error) {
// look up in URL reg
var str string = " "
var idx uint32
for len(str) > 0 {
mapaddr := storageMapping(storageIdx2Addr(1), chash[:])
key := storageAddress(storageFixedArray(mapaddr, storageIdx2Addr(idx)))
hex := self.backend.StorageAt(UrlHintAddr[2:], key)
str = string(common.Hex2Bytes(hex[2:]))
l := 0
for (l < len(str)) && (str[l] == 0) {
l++
}
str = str[l:]
uri = uri + str
idx++
}
if len(uri) == 0 {
err = fmt.Errorf("GetURLhint: URL hint not found for '%v'", chash.Hex())
}
return
}
// banBlocks retrieves a batch of blocks from a peer feeding us invalid hashes,
// and bans the head of the retrieved batch.
//
// This method only fetches one single batch as the goal is not ban an entire
// (potentially long) invalid chain - wasting a lot of time in the meanwhile -,
// but rather to gradually build up a blacklist if the peer keeps reconnecting.
func (d *Downloader) banBlocks(peerId string, head common.Hash) error {
glog.V(logger.Debug).Infof("Banning a batch out of %d blocks from %s", d.queue.Pending(), peerId)
// Ask the peer being banned for a batch of blocks from the banning point
peer := d.peers.Peer(peerId)
if peer == nil {
return nil
}
request := d.queue.Reserve(peer, MaxBlockFetch)
if request == nil {
return nil
}
if err := peer.Fetch(request); err != nil {
return err
}
// Wait a bit for the reply to arrive, and ban if done so
timeout := time.After(blockHardTTL)
for {
select {
case <-d.cancelCh:
return errCancelBlockFetch
case <-timeout:
return errTimeout
case <-d.hashCh:
// Out of bounds hashes received, ignore them
case blockPack := <-d.blockCh:
blocks := blockPack.blocks
// Short circuit if it's a stale cross check
if len(blocks) == 1 {
block := blocks[0]
if _, ok := d.checks[block.Hash()]; ok {
delete(d.checks, block.Hash())
break
}
}
// Short circuit if it's not from the peer being banned
if blockPack.peerId != peerId {
break
}
// Short circuit if no blocks were returned
if len(blocks) == 0 {
return errors.New("no blocks returned to ban")
}
// Reconstruct the original chain order and ensure we're banning the correct blocks
types.BlockBy(types.Number).Sort(blocks)
if bytes.Compare(blocks[0].Hash().Bytes(), head.Bytes()) != 0 {
return errors.New("head block not the banned one")
}
index := 0
for _, block := range blocks[1:] {
if bytes.Compare(block.ParentHash().Bytes(), blocks[index].Hash().Bytes()) != 0 {
break
}
index++
}
// Ban the head hash and phase out any excess
d.banned.Add(blocks[index].Hash())
for d.banned.Size() > maxBannedHashes {
var evacuate common.Hash
d.banned.Each(func(item interface{}) bool {
// Skip any hard coded bans
if core.BadHashes[item.(common.Hash)] {
return true
}
evacuate = item.(common.Hash)
return false
})
d.banned.Remove(evacuate)
}
glog.V(logger.Debug).Infof("Banned %d blocks from: %s", index+1, peerId)
return nil
}
}
}
func (self *StateObject) SetState(k, value common.Hash) {
self.storage[k.Str()] = value
self.dirty = true
}
