neo-go/pkg/core/interop_system.go

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package core
import (
"errors"
"fmt"
"math"
"github.com/CityOfZion/neo-go/pkg/core/transaction"
"github.com/CityOfZion/neo-go/pkg/crypto/hash"
"github.com/CityOfZion/neo-go/pkg/crypto/keys"
"github.com/CityOfZion/neo-go/pkg/smartcontract"
"github.com/CityOfZion/neo-go/pkg/util"
"github.com/CityOfZion/neo-go/pkg/vm"
gherr "github.com/pkg/errors"
log "github.com/sirupsen/logrus"
)
const (
// MaxStorageKeyLen is the maximum length of a key for storage items.
MaxStorageKeyLen = 1024
)
// StorageContext contains storing script hash and read/write flag, it's used as
// a context for storage manipulation functions.
type StorageContext struct {
ScriptHash util.Uint160
ReadOnly bool
}
// getBlockHashFromElement converts given vm.Element to block hash using given
// Blockchainer if needed. Interop functions accept both block numbers and
// block hashes as parameters, thus this function is needed.
func getBlockHashFromElement(bc Blockchainer, element *vm.Element) (util.Uint256, error) {
var hash util.Uint256
hashbytes := element.Bytes()
if len(hashbytes) <= 5 {
hashint := element.BigInt().Int64()
if hashint < 0 || hashint > math.MaxUint32 {
return hash, errors.New("bad block index")
}
hash = bc.GetHeaderHash(int(hashint))
} else {
return util.Uint256DecodeReverseBytes(hashbytes)
}
return hash, nil
}
// bcGetBlock returns current block.
func (ic *interopContext) bcGetBlock(v *vm.VM) error {
hash, err := getBlockHashFromElement(ic.bc, v.Estack().Pop())
if err != nil {
return err
}
block, err := ic.bc.GetBlock(hash)
if err != nil {
v.Estack().PushVal([]byte{})
} else {
v.Estack().PushVal(vm.NewInteropItem(block))
}
return nil
}
// bcGetContract returns contract.
func (ic *interopContext) bcGetContract(v *vm.VM) error {
hashbytes := v.Estack().Pop().Bytes()
hash, err := util.Uint160DecodeBytes(hashbytes)
if err != nil {
return err
}
cs := ic.bc.GetContractState(hash)
if cs == nil {
v.Estack().PushVal([]byte{})
} else {
v.Estack().PushVal(vm.NewInteropItem(cs))
}
return nil
}
// bcGetHeader returns block header.
func (ic *interopContext) bcGetHeader(v *vm.VM) error {
hash, err := getBlockHashFromElement(ic.bc, v.Estack().Pop())
if err != nil {
return err
}
header, err := ic.bc.GetHeader(hash)
if err != nil {
v.Estack().PushVal([]byte{})
} else {
v.Estack().PushVal(vm.NewInteropItem(header))
}
return nil
}
// bcGetHeight returns blockchain height.
func (ic *interopContext) bcGetHeight(v *vm.VM) error {
v.Estack().PushVal(ic.bc.BlockHeight())
return nil
}
// getTransactionAndHeight gets parameter from the vm evaluation stack and
// returns transaction and its height if it's present in the blockchain.
func getTransactionAndHeight(bc Blockchainer, v *vm.VM) (*transaction.Transaction, uint32, error) {
hashbytes := v.Estack().Pop().Bytes()
hash, err := util.Uint256DecodeReverseBytes(hashbytes)
if err != nil {
return nil, 0, err
}
return bc.GetTransaction(hash)
}
// bcGetTransaction returns transaction.
func (ic *interopContext) bcGetTransaction(v *vm.VM) error {
tx, _, err := getTransactionAndHeight(ic.bc, v)
if err != nil {
return err
}
v.Estack().PushVal(vm.NewInteropItem(tx))
return nil
}
// bcGetTransactionHeight returns transaction height.
func (ic *interopContext) bcGetTransactionHeight(v *vm.VM) error {
_, h, err := getTransactionAndHeight(ic.bc, v)
if err != nil {
return err
}
v.Estack().PushVal(h)
return nil
}
// popHeaderFromVM returns pointer to Header or error. It's main feature is
// proper treatment of Block structure, because C# code implicitly assumes
// that header APIs can also operate on blocks.
func popHeaderFromVM(v *vm.VM) (*Header, error) {
iface := v.Estack().Pop().Value()
header, ok := iface.(*Header)
if !ok {
block, ok := iface.(*Block)
if !ok {
return nil, errors.New("value is not a header or block")
}
return block.Header(), nil
}
return header, nil
}
// headerGetIndex returns block index from the header.
func (ic *interopContext) headerGetIndex(v *vm.VM) error {
header, err := popHeaderFromVM(v)
if err != nil {
return err
}
v.Estack().PushVal(header.Index)
return nil
}
// headerGetHash returns header hash of the passed header.
func (ic *interopContext) headerGetHash(v *vm.VM) error {
header, err := popHeaderFromVM(v)
if err != nil {
return err
}
v.Estack().PushVal(header.Hash().BytesReverse())
return nil
}
// headerGetPrevHash returns previous header hash of the passed header.
func (ic *interopContext) headerGetPrevHash(v *vm.VM) error {
header, err := popHeaderFromVM(v)
if err != nil {
return err
}
v.Estack().PushVal(header.PrevHash.BytesReverse())
return nil
}
// headerGetTimestamp returns timestamp of the passed header.
func (ic *interopContext) headerGetTimestamp(v *vm.VM) error {
header, err := popHeaderFromVM(v)
if err != nil {
return err
}
v.Estack().PushVal(header.Timestamp)
return nil
}
// blockGetTransactionCount returns transactions count in the given block.
func (ic *interopContext) blockGetTransactionCount(v *vm.VM) error {
blockInterface := v.Estack().Pop().Value()
block, ok := blockInterface.(*Block)
if !ok {
return errors.New("value is not a block")
}
v.Estack().PushVal(len(block.Transactions))
return nil
}
// blockGetTransactions returns transactions from the given block.
func (ic *interopContext) blockGetTransactions(v *vm.VM) error {
blockInterface := v.Estack().Pop().Value()
block, ok := blockInterface.(*Block)
if !ok {
return errors.New("value is not a block")
}
if len(block.Transactions) > vm.MaxArraySize {
return errors.New("too many transactions")
}
txes := make([]vm.StackItem, 0, len(block.Transactions))
for _, tx := range block.Transactions {
txes = append(txes, vm.NewInteropItem(tx))
}
v.Estack().PushVal(txes)
return nil
}
// blockGetTransaction returns transaction with the given number from the given
// block.
func (ic *interopContext) blockGetTransaction(v *vm.VM) error {
blockInterface := v.Estack().Pop().Value()
block, ok := blockInterface.(*Block)
if !ok {
return errors.New("value is not a block")
}
index := v.Estack().Pop().BigInt().Int64()
if index < 0 || index >= int64(len(block.Transactions)) {
return errors.New("wrong transaction index")
}
tx := block.Transactions[index]
v.Estack().PushVal(vm.NewInteropItem(tx))
return nil
}
// txGetHash returns transaction's hash.
func (ic *interopContext) txGetHash(v *vm.VM) error {
txInterface := v.Estack().Pop().Value()
tx, ok := txInterface.(*transaction.Transaction)
if !ok {
return errors.New("value is not a transaction")
}
v.Estack().PushVal(tx.Hash().BytesReverse())
return nil
}
// engineGetScriptContainer returns transaction that contains the script being
// run.
func (ic *interopContext) engineGetScriptContainer(v *vm.VM) error {
v.Estack().PushVal(vm.NewInteropItem(ic.tx))
return nil
}
// pushContextScriptHash returns script hash of the invocation stack element
// number n.
func getContextScriptHash(v *vm.VM, n int) util.Uint160 {
ctxIface := v.Istack().Peek(n).Value()
ctx := ctxIface.(*vm.Context)
return hash.Hash160(ctx.Program())
}
// pushContextScriptHash pushes to evaluation stack the script hash of the
// invocation stack element number n.
func pushContextScriptHash(v *vm.VM, n int) error {
h := getContextScriptHash(v, n)
v.Estack().PushVal(h.Bytes())
return nil
}
// engineGetExecutingScriptHash returns executing script hash.
func (ic *interopContext) engineGetExecutingScriptHash(v *vm.VM) error {
return pushContextScriptHash(v, 0)
}
// engineGetCallingScriptHash returns calling script hash.
func (ic *interopContext) engineGetCallingScriptHash(v *vm.VM) error {
return pushContextScriptHash(v, 1)
}
// engineGetEntryScriptHash returns entry script hash.
func (ic *interopContext) engineGetEntryScriptHash(v *vm.VM) error {
return pushContextScriptHash(v, v.Istack().Len()-1)
}
// runtimePlatform returns the name of the platform.
func (ic *interopContext) runtimePlatform(v *vm.VM) error {
v.Estack().PushVal([]byte("NEO"))
return nil
}
// runtimeGetTrigger returns the script trigger.
func (ic *interopContext) runtimeGetTrigger(v *vm.VM) error {
v.Estack().PushVal(ic.trigger)
return nil
}
// checkHashedWitness checks given hash against current list of script hashes
// for verifying in the interop context.
func (ic *interopContext) checkHashedWitness(hash util.Uint160) (bool, error) {
hashes, err := ic.bc.GetScriptHashesForVerifying(ic.tx)
if err != nil {
return false, gherr.Wrap(err, "failed to get script hashes")
}
for _, v := range hashes {
if hash.Equals(v) {
return true, nil
}
}
return false, nil
}
// checkKeyedWitness checks hash of signature check contract with a given public
// key against current list of script hashes for verifying in the interop context.
func (ic *interopContext) checkKeyedWitness(key *keys.PublicKey) (bool, error) {
script, err := smartcontract.CreateSignatureRedeemScript(key)
if err != nil {
return false, gherr.Wrap(err, "failed to create signature script for a key")
}
return ic.checkHashedWitness(hash.Hash160(script))
}
// runtimeCheckWitness should check witnesses.
func (ic *interopContext) runtimeCheckWitness(v *vm.VM) error {
var res bool
var err error
hashOrKey := v.Estack().Pop().Bytes()
hash, err := util.Uint160DecodeBytes(hashOrKey)
if err != nil {
key := &keys.PublicKey{}
err = key.DecodeBytes(hashOrKey)
if err != nil {
return errors.New("parameter given is neither a key nor a hash")
}
res, err = ic.checkKeyedWitness(key)
} else {
res, err = ic.checkHashedWitness(hash)
}
if err != nil {
return gherr.Wrap(err, "failed to check")
}
v.Estack().PushVal(res)
return nil
}
// runtimeNotify should pass stack item to the notify plugin to handle it, but
// in neo-go the only meaningful thing to do here is to log.
func (ic *interopContext) runtimeNotify(v *vm.VM) error {
msg := fmt.Sprintf("%q", v.Estack().Pop().Bytes())
log.Infof("script %s notifies: %s", getContextScriptHash(v, 0), msg)
return nil
}
// runtimeLog log the message passed.
func (ic *interopContext) runtimeLog(v *vm.VM) error {
msg := fmt.Sprintf("%q", v.Estack().Pop().Bytes())
log.Infof("script %s logs: %s", getContextScriptHash(v, 0), msg)
return nil
}
// runtimeGetTime returns timestamp of the block being verified, or the latest
// one in the blockchain if no block is given to interopContext.
func (ic *interopContext) runtimeGetTime(v *vm.VM) error {
var header *Header
if ic.block == nil {
var err error
header, err = ic.bc.GetHeader(ic.bc.CurrentBlockHash())
if err != nil {
return err
}
} else {
header = ic.block.Header()
}
v.Estack().PushVal(header.Timestamp)
return nil
}
/*
// runtimeSerialize should serialize given stack item.
func (ic *interopContext) runtimeSerialize(v *vm.VM) error {
panic("TODO")
}
// runtimeDeserialize should deserialize given stack item.
func (ic *interopContext) runtimeDeserialize(v *vm.VM) error {
panic("TODO")
}
*/
func (ic *interopContext) checkStorageContext(stc *StorageContext) error {
contract := ic.bc.GetContractState(stc.ScriptHash)
if contract == nil {
return errors.New("no contract found")
}
if !contract.HasStorage() {
return errors.New("contract can't have storage")
}
return nil
}
// storageDelete deletes stored key-value pair.
func (ic *interopContext) storageDelete(v *vm.VM) error {
if ic.trigger != 0x10 && ic.trigger != 0x11 {
return errors.New("can't delete when the trigger is not application")
}
stcInterface := v.Estack().Pop().Value()
stc, ok := stcInterface.(*StorageContext)
if !ok {
return fmt.Errorf("%T is not a StorageContext", stcInterface)
}
if stc.ReadOnly {
return errors.New("StorageContext is read only")
}
err := ic.checkStorageContext(stc)
if err != nil {
return err
}
key := v.Estack().Pop().Bytes()
si := getStorageItemFromStore(ic.mem, stc.ScriptHash, key)
if si == nil {
si = ic.bc.GetStorageItem(stc.ScriptHash, key)
}
if si != nil && si.IsConst {
return errors.New("storage item is constant")
}
return deleteStorageItemInStore(ic.mem, stc.ScriptHash, key)
}
// storageGet returns stored key-value pair.
func (ic *interopContext) storageGet(v *vm.VM) error {
stcInterface := v.Estack().Pop().Value()
stc, ok := stcInterface.(*StorageContext)
if !ok {
return fmt.Errorf("%T is not a StorageContext", stcInterface)
}
err := ic.checkStorageContext(stc)
if err != nil {
return err
}
key := v.Estack().Pop().Bytes()
si := getStorageItemFromStore(ic.mem, stc.ScriptHash, key)
if si == nil {
si = ic.bc.GetStorageItem(stc.ScriptHash, key)
}
if si != nil && si.Value != nil {
v.Estack().PushVal(si.Value)
} else {
v.Estack().PushVal([]byte{})
}
return nil
}
// storageGetContext returns storage context (scripthash).
func (ic *interopContext) storageGetContext(v *vm.VM) error {
sc := &StorageContext{
ScriptHash: getContextScriptHash(v, 0),
ReadOnly: false,
}
v.Estack().PushVal(vm.NewInteropItem(sc))
return nil
}
// storageGetReadOnlyContext returns read-only context (scripthash).
func (ic *interopContext) storageGetReadOnlyContext(v *vm.VM) error {
sc := &StorageContext{
ScriptHash: getContextScriptHash(v, 0),
ReadOnly: true,
}
v.Estack().PushVal(vm.NewInteropItem(sc))
return nil
}
func (ic *interopContext) putWithContextAndFlags(stc *StorageContext, key []byte, value []byte, isConst bool) error {
if ic.trigger != 0x10 && ic.trigger != 0x11 {
return errors.New("can't delete when the trigger is not application")
}
if len(key) > MaxStorageKeyLen {
return errors.New("key is too big")
}
if stc.ReadOnly {
return errors.New("StorageContext is read only")
}
err := ic.checkStorageContext(stc)
if err != nil {
return err
}
si := getStorageItemFromStore(ic.mem, stc.ScriptHash, key)
if si == nil {
si = ic.bc.GetStorageItem(stc.ScriptHash, key)
if si == nil {
si = &StorageItem{}
}
}
if si.IsConst {
return errors.New("storage item exists and is read-only")
}
si.Value = value
si.IsConst = isConst
return putStorageItemIntoStore(ic.mem, stc.ScriptHash, key, si)
}
// storagePutInternal is a unified implementation of storagePut and storagePutEx.
func (ic *interopContext) storagePutInternal(v *vm.VM, getFlag bool) error {
stcInterface := v.Estack().Pop().Value()
stc, ok := stcInterface.(*StorageContext)
if !ok {
return fmt.Errorf("%T is not a StorageContext", stcInterface)
}
key := v.Estack().Pop().Bytes()
value := v.Estack().Pop().Bytes()
var flag int
if getFlag {
flag = int(v.Estack().Pop().BigInt().Int64())
}
return ic.putWithContextAndFlags(stc, key, value, flag == 1)
}
// storagePut puts key-value pair into the storage.
func (ic *interopContext) storagePut(v *vm.VM) error {
return ic.storagePutInternal(v, false)
}
// storagePutEx puts key-value pair with given flags into the storage.
func (ic *interopContext) storagePutEx(v *vm.VM) error {
return ic.storagePutInternal(v, true)
}
// storageContextAsReadOnly sets given context to read-only mode.
func (ic *interopContext) storageContextAsReadOnly(v *vm.VM) error {
stcInterface := v.Estack().Pop().Value()
stc, ok := stcInterface.(*StorageContext)
if !ok {
return fmt.Errorf("%T is not a StorageContext", stcInterface)
}
if !stc.ReadOnly {
stx := &StorageContext{
ScriptHash: stc.ScriptHash,
ReadOnly: true,
}
stc = stx
}
v.Estack().PushVal(vm.NewInteropItem(stc))
return nil
}
// contractDestroy destroys a contract.
func (ic *interopContext) contractDestroy(v *vm.VM) error {
if ic.trigger != 0x10 {
return errors.New("can't destroy contract when not triggered by application")
}
hash := getContextScriptHash(v, 0)
cs := ic.bc.GetContractState(hash)
if cs == nil {
return nil
}
err := deleteContractStateInStore(ic.mem, hash)
if err != nil {
return err
}
if cs.HasStorage() {
siMap, err := ic.bc.GetStorageItems(hash)
if err != nil {
return err
}
for k := range siMap {
_ = deleteStorageItemInStore(ic.mem, hash, []byte(k))
}
}
return nil
}
// contractGetStorageContext retrieves StorageContext of a contract.
func (ic *interopContext) contractGetStorageContext(v *vm.VM) error {
csInterface := v.Estack().Pop().Value()
cs, ok := csInterface.(*ContractState)
if !ok {
return fmt.Errorf("%T is not a contract state", cs)
}
if getContractStateFromStore(ic.mem, cs.ScriptHash()) == nil {
return fmt.Errorf("contract was not created in this transaction")
}
stc := &StorageContext{
ScriptHash: cs.ScriptHash(),
}
v.Estack().PushVal(vm.NewInteropItem(stc))
return nil
}