package runtime import ( "errors" "fmt" "math/big" "github.com/nspcc-dev/neo-go/pkg/core/interop" "github.com/nspcc-dev/neo-go/pkg/vm/stackitem" "go.uber.org/zap" ) const ( // MaxEventNameLen is the maximum length of a name for event. MaxEventNameLen = 32 // MaxNotificationSize is the maximum length of a runtime log message. MaxNotificationSize = 1024 ) // GetExecutingScriptHash returns executing script hash. func GetExecutingScriptHash(ic *interop.Context) error { return ic.VM.PushContextScriptHash(0) } // GetCallingScriptHash returns calling script hash. // While Executing and Entry script hashes are always valid for non-native contracts, // Calling hash is set explicitly when native contracts are used, because when switching from // one native to another, no operations are performed on invocation stack. func GetCallingScriptHash(ic *interop.Context) error { h := ic.VM.GetCallingScriptHash() ic.VM.Estack().PushItem(stackitem.NewByteArray(h.BytesBE())) return nil } // GetEntryScriptHash returns entry script hash. func GetEntryScriptHash(ic *interop.Context) error { return ic.VM.PushContextScriptHash(ic.VM.Istack().Len() - 1) } // Platform returns the name of the platform. func Platform(ic *interop.Context) error { ic.VM.Estack().PushItem(stackitem.NewByteArray([]byte("NEO"))) return nil } // GetTrigger returns the script trigger. func GetTrigger(ic *interop.Context) error { ic.VM.Estack().PushItem(stackitem.NewBigInteger(big.NewInt(int64(ic.Trigger)))) return nil } // Notify 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 Notify(ic *interop.Context) error { name := ic.VM.Estack().Pop().String() elem := ic.VM.Estack().Pop() args := elem.Array() if len(name) > MaxEventNameLen { return fmt.Errorf("event name must be less than %d", MaxEventNameLen) } // But it has to be serializable, otherwise we either have some broken // (recursive) structure inside or an interop item that can't be used // outside of the interop subsystem anyway. bytes, err := stackitem.Serialize(elem.Item()) if err != nil { return fmt.Errorf("bad notification: %w", err) } if len(bytes) > MaxNotificationSize { return fmt.Errorf("notification size shouldn't exceed %d", MaxNotificationSize) } ic.AddNotification(ic.VM.GetCurrentScriptHash(), name, stackitem.DeepCopy(stackitem.NewArray(args)).(*stackitem.Array)) return nil } // Log logs the message passed. func Log(ic *interop.Context) error { state := ic.VM.Estack().Pop().String() if len(state) > MaxNotificationSize { return fmt.Errorf("message length shouldn't exceed %v", MaxNotificationSize) } var txHash string if ic.Tx != nil { txHash = ic.Tx.Hash().StringLE() } ic.Log.Info("runtime log", zap.String("tx", txHash), zap.String("script", ic.VM.GetCurrentScriptHash().StringLE()), zap.String("msg", state)) return nil } // GetTime returns timestamp of the block being verified, or the latest // one in the blockchain if no block is given to Context. func GetTime(ic *interop.Context) error { ic.VM.Estack().PushItem(stackitem.NewBigInteger(new(big.Int).SetUint64(ic.Block.Timestamp))) return nil } // BurnGas burns GAS to benefit NEO ecosystem. func BurnGas(ic *interop.Context) error { gas := ic.VM.Estack().Pop().BigInt() if !gas.IsInt64() { return errors.New("invalid GAS value") } g := gas.Int64() if g <= 0 { return errors.New("GAS must be positive") } if !ic.VM.AddGas(g) { return errors.New("GAS limit exceeded") } return nil }