Merge pull request #2723 from nspcc-dev/smart-vm-cli

vm: make VM CLI state-dependant

cli/options/filtering_core.go

@@ -0,0 +1,28 @@
+package options
+
+import "go.uber.org/zap/zapcore"
+
+// FilteringCore is custom implementation of zapcore.Core that allows to filter
+// log entries using custom filtering function.
+type FilteringCore struct {
+	zapcore.Core
+	filter FilterFunc
+}
+
+// FilterFunc is the filter function that is called to check whether the given
+// entry together with the associated fields is to be written to a core or not.
+type FilterFunc func(zapcore.Entry) bool
+
+// NewFilteringCore returns a core middleware that uses the given filter function
+// to decide whether to log this message or not.
+func NewFilteringCore(next zapcore.Core, filter FilterFunc) zapcore.Core {
+	return &FilteringCore{next, filter}
+}
+
+// Check implements zapcore.Core interface and performs log entries filtering.
+func (c *FilteringCore) Check(e zapcore.Entry, ce *zapcore.CheckedEntry) *zapcore.CheckedEntry {
+	if c.filter(e) {
+		return c.Core.Check(e, ce)
+	}
+	return ce
+}

cli/options/options.go

@@ -6,15 +6,23 @@ package options
 import (
 	"context"
 	"errors"
+	"fmt"
+	"net/url"
+	"os"
+	"runtime"
 	"strconv"
 	"time"
 
+	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/invoker"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/urfave/cli"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 )
 
 // DefaultTimeout is the default timeout used for RPC requests.
@@ -52,6 +60,18 @@ var Historic = cli.StringFlag{
 	Usage: "Use historic state (height, block hash or state root hash)",
 }
 
+// Config is a flag for commands that use node configuration.
+var Config = cli.StringFlag{
+	Name:  "config-path",
+	Usage: "path to directory with configuration files",
+}
+
+// Debug is a flag for commands that allow node in debug mode usage.
+var Debug = cli.BoolFlag{
+	Name:  "debug, d",
+	Usage: "enable debug logging (LOTS of output)",
+}
+
 var errNoEndpoint = errors.New("no RPC endpoint specified, use option '--" + RPCEndpointFlag + "' or '-r'")
 var errInvalidHistoric = errors.New("invalid 'historic' parameter, neither a block number, nor a block/state hash")
 
@@ -128,3 +148,95 @@ func GetRPCWithInvoker(gctx context.Context, ctx *cli.Context, signers []transac
 	}
 	return c, inv, err
 }
+
+// GetConfigFromContext looks at the path and the mode flags in the given config and
+// returns an appropriate config.
+func GetConfigFromContext(ctx *cli.Context) (config.Config, error) {
+	configPath := "./config"
+	if argCp := ctx.String("config-path"); argCp != "" {
+		configPath = argCp
+	}
+	return config.Load(configPath, GetNetwork(ctx))
+}
+
+var (
+	// _winfileSinkRegistered denotes whether zap has registered
+	// user-supplied factory for all sinks with `winfile`-prefixed scheme.
+	_winfileSinkRegistered bool
+	_winfileSinkCloser     func() error
+)
+
+// HandleLoggingParams reads logging parameters.
+// If a user selected debug level -- function enables it.
+// If logPath is configured -- function creates a dir and a file for logging.
+// If logPath is configured on Windows -- function returns closer to be
+// able to close sink for the opened log output file.
+func HandleLoggingParams(debug bool, cfg config.ApplicationConfiguration) (*zap.Logger, func() error, error) {
+	level := zapcore.InfoLevel
+	if debug {
+		level = zapcore.DebugLevel
+	}
+
+	cc := zap.NewProductionConfig()
+	cc.DisableCaller = true
+	cc.DisableStacktrace = true
+	cc.EncoderConfig.EncodeDuration = zapcore.StringDurationEncoder
+	cc.EncoderConfig.EncodeLevel = zapcore.CapitalLevelEncoder
+	cc.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
+	cc.Encoding = "console"
+	cc.Level = zap.NewAtomicLevelAt(level)
+	cc.Sampling = nil
+
+	if logPath := cfg.LogPath; logPath != "" {
+		if err := io.MakeDirForFile(logPath, "logger"); err != nil {
+			return nil, nil, err
+		}
+
+		if runtime.GOOS == "windows" {
+			if !_winfileSinkRegistered {
+				// See https://github.com/uber-go/zap/issues/621.
+				err := zap.RegisterSink("winfile", func(u *url.URL) (zap.Sink, error) {
+					if u.User != nil {
+						return nil, fmt.Errorf("user and password not allowed with file URLs: got %v", u)
+					}
+					if u.Fragment != "" {
+						return nil, fmt.Errorf("fragments not allowed with file URLs: got %v", u)
+					}
+					if u.RawQuery != "" {
+						return nil, fmt.Errorf("query parameters not allowed with file URLs: got %v", u)
+					}
+					// Error messages are better if we check hostname and port separately.
+					if u.Port() != "" {
+						return nil, fmt.Errorf("ports not allowed with file URLs: got %v", u)
+					}
+					if hn := u.Hostname(); hn != "" && hn != "localhost" {
+						return nil, fmt.Errorf("file URLs must leave host empty or use localhost: got %v", u)
+					}
+					switch u.Path {
+					case "stdout":
+						return os.Stdout, nil
+					case "stderr":
+						return os.Stderr, nil
+					}
+					f, err := os.OpenFile(u.Path[1:], // Remove leading slash left after url.Parse.
+						os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0644)
+					_winfileSinkCloser = func() error {
+						_winfileSinkCloser = nil
+						return f.Close()
+					}
+					return f, err
+				})
+				if err != nil {
+					return nil, nil, fmt.Errorf("failed to register windows-specific sinc: %w", err)
+				}
+				_winfileSinkRegistered = true
+			}
+			logPath = "winfile:///" + logPath
+		}
+
+		cc.OutputPaths = []string{logPath}
+	}
+
+	log, err := cc.Build()
+	return log, _winfileSinkCloser, err
+}

cli/server/cli_dump_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/nspcc-dev/neo-go/internal/testcli"
 	"github.com/nspcc-dev/neo-go/pkg/config"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v3"
 )
@@ -19,7 +20,7 @@ func TestDBRestoreDump(t *testing.T) {
 		chainPath := filepath.Join(tmpDir, "neogotestchain")
 		cfg, err := config.LoadFile(filepath.Join("..", "..", "config", "protocol.unit_testnet.yml"))
 		require.NoError(t, err, "could not load config")
-		cfg.ApplicationConfiguration.DBConfiguration.Type = "leveldb"
+		cfg.ApplicationConfiguration.DBConfiguration.Type = dbconfig.LevelDB
 		cfg.ApplicationConfiguration.DBConfiguration.LevelDBOptions.DataDirectoryPath = chainPath
 		return cfg
 	}

cli/server/cli_server_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/nspcc-dev/neo-go/cli/server"
 	"github.com/nspcc-dev/neo-go/internal/testcli"
 	"github.com/nspcc-dev/neo-go/pkg/config"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v3"
 )
@@ -25,7 +26,7 @@ func TestServerStart(t *testing.T) {
 	saveCfg := func(t *testing.T, f func(cfg *config.Config)) string {
 		cfg := *ptr
 		chainPath := filepath.Join(t.TempDir(), "neogotestchain")
-		cfg.ApplicationConfiguration.DBConfiguration.Type = "leveldb"
+		cfg.ApplicationConfiguration.DBConfiguration.Type = dbconfig.LevelDB
 		cfg.ApplicationConfiguration.DBConfiguration.LevelDBOptions.DataDirectoryPath = chainPath
 		f(&cfg)
 		out, err := yaml.Marshal(cfg)

cli/server/server.go

@@ -4,10 +4,8 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"net/url"
 	"os"
 	"os/signal"
-	"runtime"
 	"syscall"
 	"time"
 
@@ -31,25 +29,15 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/services/stateroot"
 	"github.com/urfave/cli"
 	"go.uber.org/zap"
-	"go.uber.org/zap/zapcore"
-)
-
-var (
-	// _winfileSinkRegistered denotes whether zap has registered
-	// user-supplied factory for all sinks with `winfile`-prefixed scheme.
-	_winfileSinkRegistered bool
-	_winfileSinkCloser     func() error
 )
 
 // NewCommands returns 'node' command.
 func NewCommands() []cli.Command {
-	var cfgFlags = []cli.Flag{
+	cfgFlags := []cli.Flag{options.Config}
-		cli.StringFlag{Name: "config-path", Usage: "path to directory with configuration files"},
-	}
 	cfgFlags = append(cfgFlags, options.Network...)
 	var cfgWithCountFlags = make([]cli.Flag, len(cfgFlags))
 	copy(cfgWithCountFlags, cfgFlags)
-	cfgFlags = append(cfgFlags, cli.BoolFlag{Name: "debug, d", Usage: "enable debug logging (LOTS of output)"})
+	cfgFlags = append(cfgFlags, options.Debug)
 
 	cfgWithCountFlags = append(cfgWithCountFlags,
 		cli.UintFlag{
@@ -128,91 +116,6 @@ func newGraceContext() context.Context {
 	return ctx
 }
 
-// getConfigFromContext looks at the path and the mode flags in the given config and
-// returns an appropriate config.
-func getConfigFromContext(ctx *cli.Context) (config.Config, error) {
-	configPath := "./config"
-	if argCp := ctx.String("config-path"); argCp != "" {
-		configPath = argCp
-	}
-	return config.Load(configPath, options.GetNetwork(ctx))
-}
-
-// handleLoggingParams reads logging parameters.
-// If a user selected debug level -- function enables it.
-// If logPath is configured -- function creates a dir and a file for logging.
-// If logPath is configured on Windows -- function returns closer to be
-// able to close sink for the opened log output file.
-func handleLoggingParams(ctx *cli.Context, cfg config.ApplicationConfiguration) (*zap.Logger, func() error, error) {
-	level := zapcore.InfoLevel
-	if ctx.Bool("debug") {
-		level = zapcore.DebugLevel
-	}
-
-	cc := zap.NewProductionConfig()
-	cc.DisableCaller = true
-	cc.DisableStacktrace = true
-	cc.EncoderConfig.EncodeDuration = zapcore.StringDurationEncoder
-	cc.EncoderConfig.EncodeLevel = zapcore.CapitalLevelEncoder
-	cc.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
-	cc.Encoding = "console"
-	cc.Level = zap.NewAtomicLevelAt(level)
-	cc.Sampling = nil
-
-	if logPath := cfg.LogPath; logPath != "" {
-		if err := io.MakeDirForFile(logPath, "logger"); err != nil {
-			return nil, nil, err
-		}
-
-		if runtime.GOOS == "windows" {
-			if !_winfileSinkRegistered {
-				// See https://github.com/uber-go/zap/issues/621.
-				err := zap.RegisterSink("winfile", func(u *url.URL) (zap.Sink, error) {
-					if u.User != nil {
-						return nil, fmt.Errorf("user and password not allowed with file URLs: got %v", u)
-					}
-					if u.Fragment != "" {
-						return nil, fmt.Errorf("fragments not allowed with file URLs: got %v", u)
-					}
-					if u.RawQuery != "" {
-						return nil, fmt.Errorf("query parameters not allowed with file URLs: got %v", u)
-					}
-					// Error messages are better if we check hostname and port separately.
-					if u.Port() != "" {
-						return nil, fmt.Errorf("ports not allowed with file URLs: got %v", u)
-					}
-					if hn := u.Hostname(); hn != "" && hn != "localhost" {
-						return nil, fmt.Errorf("file URLs must leave host empty or use localhost: got %v", u)
-					}
-					switch u.Path {
-					case "stdout":
-						return os.Stdout, nil
-					case "stderr":
-						return os.Stderr, nil
-					}
-					f, err := os.OpenFile(u.Path[1:], // Remove leading slash left after url.Parse.
-						os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0644)
-					_winfileSinkCloser = func() error {
-						_winfileSinkCloser = nil
-						return f.Close()
-					}
-					return f, err
-				})
-				if err != nil {
-					return nil, nil, fmt.Errorf("failed to register windows-specific sinc: %w", err)
-				}
-				_winfileSinkRegistered = true
-			}
-			logPath = "winfile:///" + logPath
-		}
-
-		cc.OutputPaths = []string{logPath}
-	}
-
-	log, err := cc.Build()
-	return log, _winfileSinkCloser, err
-}
-
 func initBCWithMetrics(cfg config.Config, log *zap.Logger) (*core.Blockchain, *metrics.Service, *metrics.Service, error) {
 	chain, err := initBlockChain(cfg, log)
 	if err != nil {
@@ -233,11 +136,11 @@ func dumpDB(ctx *cli.Context) error {
 	if err := cmdargs.EnsureNone(ctx); err != nil {
 		return err
 	}
-	cfg, err := getConfigFromContext(ctx)
+	cfg, err := options.GetConfigFromContext(ctx)
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}
-	log, logCloser, err := handleLoggingParams(ctx, cfg.ApplicationConfiguration)
+	log, logCloser, err := options.HandleLoggingParams(ctx.Bool("debug"), cfg.ApplicationConfiguration)
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}
@@ -286,11 +189,11 @@ func restoreDB(ctx *cli.Context) error {
 	if err := cmdargs.EnsureNone(ctx); err != nil {
 		return err
 	}
-	cfg, err := getConfigFromContext(ctx)
+	cfg, err := options.GetConfigFromContext(ctx)
 	if err != nil {
 		return err
 	}
-	log, logCloser, err := handleLoggingParams(ctx, cfg.ApplicationConfiguration)
+	log, logCloser, err := options.HandleLoggingParams(ctx.Bool("debug"), cfg.ApplicationConfiguration)
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}
@@ -472,11 +375,11 @@ func startServer(ctx *cli.Context) error {
 		return err
 	}
 
-	cfg, err := getConfigFromContext(ctx)
+	cfg, err := options.GetConfigFromContext(ctx)
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}
-	log, logCloser, err := handleLoggingParams(ctx, cfg.ApplicationConfiguration)
+	log, logCloser, err := options.HandleLoggingParams(ctx.Bool("debug"), cfg.ApplicationConfiguration)
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}
@@ -549,7 +452,7 @@ Main:
 			cancel()
 		case sig := <-sigCh:
 			log.Info("signal received", zap.Stringer("name", sig))
-			cfgnew, err := getConfigFromContext(ctx)
+			cfgnew, err := options.GetConfigFromContext(ctx)
 			if err != nil {
 				log.Warn("can't reread the config file, signal ignored", zap.Error(err))
 				break // Continue working.

cli/server/server_test.go

@@ -7,12 +7,14 @@ import (
 	"path/filepath"
 	"testing"
 
+	"go.uber.org/zap/zapcore"
+
+	"github.com/nspcc-dev/neo-go/cli/options"
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
 	"github.com/stretchr/testify/require"
 	"github.com/urfave/cli"
-	"go.uber.org/zap"
 	"gopkg.in/yaml.v3"
 )
 
@@ -32,7 +34,7 @@ func TestGetConfigFromContext(t *testing.T) {
 	set.String("config-path", "../../config", "")
 	set.Bool("testnet", true, "")
 	ctx := cli.NewContext(cli.NewApp(), set, nil)
-	cfg, err := getConfigFromContext(ctx)
+	cfg, err := options.GetConfigFromContext(ctx)
 	require.NoError(t, err)
 	require.Equal(t, netmode.TestNet, cfg.ProtocolConfiguration.Magic)
 }
@@ -44,49 +46,42 @@ func TestHandleLoggingParams(t *testing.T) {
 	t.Run("logdir is a file", func(t *testing.T) {
 		logfile := filepath.Join(d, "logdir")
 		require.NoError(t, os.WriteFile(logfile, []byte{1, 2, 3}, os.ModePerm))
-		set := flag.NewFlagSet("flagSet", flag.ExitOnError)
-		ctx := cli.NewContext(cli.NewApp(), set, nil)
 		cfg := config.ApplicationConfiguration{
 			LogPath: filepath.Join(logfile, "file.log"),
 		}
-		_, closer, err := handleLoggingParams(ctx, cfg)
+		_, closer, err := options.HandleLoggingParams(false, cfg)
 		require.Error(t, err)
 		require.Nil(t, closer)
 	})
 
 	t.Run("default", func(t *testing.T) {
-		set := flag.NewFlagSet("flagSet", flag.ExitOnError)
-		ctx := cli.NewContext(cli.NewApp(), set, nil)
 		cfg := config.ApplicationConfiguration{
 			LogPath: testLog,
 		}
-		logger, closer, err := handleLoggingParams(ctx, cfg)
+		logger, closer, err := options.HandleLoggingParams(false, cfg)
 		require.NoError(t, err)
 		t.Cleanup(func() {
 			if closer != nil {
 				require.NoError(t, closer())
 			}
 		})
-		require.True(t, logger.Core().Enabled(zap.InfoLevel))
+		require.True(t, logger.Core().Enabled(zapcore.InfoLevel))
-		require.False(t, logger.Core().Enabled(zap.DebugLevel))
+		require.False(t, logger.Core().Enabled(zapcore.DebugLevel))
 	})
 
 	t.Run("debug", func(t *testing.T) {
-		set := flag.NewFlagSet("flagSet", flag.ExitOnError)
-		set.Bool("debug", true, "")
-		ctx := cli.NewContext(cli.NewApp(), set, nil)
 		cfg := config.ApplicationConfiguration{
 			LogPath: testLog,
 		}
-		logger, closer, err := handleLoggingParams(ctx, cfg)
+		logger, closer, err := options.HandleLoggingParams(true, cfg)
 		require.NoError(t, err)
 		t.Cleanup(func() {
 			if closer != nil {
 				require.NoError(t, closer())
 			}
 		})
-		require.True(t, logger.Core().Enabled(zap.InfoLevel))
+		require.True(t, logger.Core().Enabled(zapcore.InfoLevel))
-		require.True(t, logger.Core().Enabled(zap.DebugLevel))
+		require.True(t, logger.Core().Enabled(zapcore.DebugLevel))
 	})
 }
 
@@ -101,9 +96,9 @@ func TestInitBCWithMetrics(t *testing.T) {
 	set.Bool("testnet", true, "")
 	set.Bool("debug", true, "")
 	ctx := cli.NewContext(cli.NewApp(), set, nil)
-	cfg, err := getConfigFromContext(ctx)
+	cfg, err := options.GetConfigFromContext(ctx)
 	require.NoError(t, err)
-	logger, closer, err := handleLoggingParams(ctx, cfg.ApplicationConfiguration)
+	logger, closer, err := options.HandleLoggingParams(true, cfg.ApplicationConfiguration)
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		if closer != nil {
@@ -349,7 +344,7 @@ func TestInitBlockChain(t *testing.T) {
 		_, err := initBlockChain(config.Config{
 			ApplicationConfiguration: config.ApplicationConfiguration{
 				DBConfiguration: dbconfig.DBConfiguration{
-					Type: "inmemory",
+					Type: dbconfig.InMemoryDB,
 				},
 			},
 		}, nil)

cli/util/convert.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 
 	"github.com/nspcc-dev/neo-go/cli/options"
-	vmcli "github.com/nspcc-dev/neo-go/pkg/vm/cli"
+	vmcli "github.com/nspcc-dev/neo-go/cli/vm"
 	"github.com/urfave/cli"
 )
 

cli/vm/cli.go

@@ -1,9 +1,10 @@
-package cli
+package vm
 
 import (
 	"bytes"
 	"crypto/elliptic"
 	"encoding/base64"
+	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
 	"errors"
@@ -17,22 +18,34 @@ import (
 
 	"github.com/chzyer/readline"
 	"github.com/kballard/go-shellquote"
+	"github.com/nspcc-dev/neo-go/cli/flags"
+	"github.com/nspcc-dev/neo-go/cli/options"
 	"github.com/nspcc-dev/neo-go/pkg/compiler"
 	"github.com/nspcc-dev/neo-go/pkg/config"
+	"github.com/nspcc-dev/neo-go/pkg/core"
+	"github.com/nspcc-dev/neo-go/pkg/core/interop"
+	"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
 	"github.com/urfave/cli"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 )
 
 const (
-	vmKey               = "vm"
+	chainKey            = "chain"
+	chainCfgKey         = "chainCfg"
+	icKey               = "ic"
 	manifestKey         = "manifest"
 	exitFuncKey         = "exitFunc"
 	readlineInstanceKey = "readlineKey"
@@ -44,6 +57,20 @@ const (
 	stringType          = "string"
 )
 
+// Various flag names.
+const (
+	verboseFlagFullName   = "verbose"
+	historicFlagFullName  = "historic"
+	backwardsFlagFullName = "backwards"
+	diffFlagFullName      = "diff"
+)
+
+var historicFlag = cli.IntFlag{
+	Name: historicFlagFullName,
+	Usage: "Height for historic script invocation (for MPT-enabled blockchain configuration with KeepOnlyLatestState setting disabled). " +
+		"Assuming that block N-th is specified as an argument, the historic invocation is based on the storage state of height N and fake currently-accepting block with index N+1.",
+}
+
 var commands = []cli.Command{
 	{
 		Name:        "exit",
@@ -100,7 +127,8 @@ var commands = []cli.Command{
 		Name:      "loadnef",
 		Usage:     "Load a NEF-consistent script into the VM",
 		UsageText: `loadnef <file> <manifest>`,
-		Description: `loadnef <file> <manifest>
+		Flags:     []cli.Flag{historicFlag},
+		Description: `loadnef [--historic <height>] <file> <manifest>
 both parameters are mandatory, example:
 > loadnef /path/to/script.nef /path/to/manifest.json`,
 		Action: handleLoadNEF,
@@ -108,8 +136,9 @@ both parameters are mandatory, example:
 	{
 		Name:      "loadbase64",
 		Usage:     "Load a base64-encoded script string into the VM",
-		UsageText: `loadbase64 <string>`,
+		UsageText: `loadbase64 [--historic <height>] <string>`,
-		Description: `loadbase64 <string>
+		Flags:     []cli.Flag{historicFlag},
+		Description: `loadbase64 [--historic <height>] <string>
 
 <string> is mandatory parameter, example:
 > loadbase64 AwAQpdToAAAADBQV9ehtQR1OrVZVhtHtoUHRfoE+agwUzmFvf3Rhfg/EuAVYOvJgKiON9j8TwAwIdHJhbnNmZXIMFDt9NxHG8Mz5sdypA9G/odiW8SOMQWJ9W1I4`,
@@ -118,8 +147,9 @@ both parameters are mandatory, example:
 	{
 		Name:      "loadhex",
 		Usage:     "Load a hex-encoded script string into the VM",
-		UsageText: `loadhex <string>`,
+		UsageText: `loadhex [--historic <height>] <string>`,
-		Description: `loadhex <string>
+		Flags:     []cli.Flag{historicFlag},
+		Description: `loadhex [--historic <height>] <string>
 
 <string> is mandatory parameter, example:
 > loadhex 0c0c48656c6c6f20776f726c6421`,
@@ -128,8 +158,9 @@ both parameters are mandatory, example:
 	{
 		Name:      "loadgo",
 		Usage:     "Compile and load a Go file with the manifest into the VM",
-		UsageText: `loadgo <file>`,
+		UsageText: `loadgo [--historic <height>] <file>`,
-		Description: `loadgo <file>
+		Flags:     []cli.Flag{historicFlag},
+		Description: `loadgo [--historic <height>] <file>
 
 <file> is mandatory parameter, example:
 > loadgo /path/to/file.go`,
@@ -137,7 +168,8 @@ both parameters are mandatory, example:
 	},
 	{
 		Name:   "reset",
-		Usage:  "Unload compiled script from the VM",
+		Usage:  "Unload compiled script from the VM and reset context to proper (possibly, historic) state",
+		Flags:  []cli.Flag{historicFlag},
 		Action: handleReset,
 	},
 	{
@@ -218,6 +250,84 @@ example:
 		Description: "Dump opcodes of the current loaded program",
 		Action:      handleOps,
 	},
+	{
+		Name:        "events",
+		Usage:       "Dump events emitted by the current loaded program",
+		Description: "Dump events emitted by the current loaded program",
+		Action:      handleEvents,
+	},
+	{
+		Name:      "env",
+		Usage:     "Dump state of the chain that is used for VM CLI invocations (use -v for verbose node configuration)",
+		UsageText: `env [-v]`,
+		Flags: []cli.Flag{
+			cli.BoolFlag{
+				Name:  verboseFlagFullName + ",v",
+				Usage: "Print the whole blockchain node configuration.",
+			},
+		},
+		Description: `env [-v]
+
+Dump state of the chain that is used for VM CLI invocations (use -v for verbose node configuration).
+
+Example:
+> env -v`,
+		Action: handleEnv,
+	},
+	{
+		Name: "storage",
+		Usage: "Dump storage of the contract with the specified hash, address or ID as is at the current stage of script invocation. " +
+			"Can be used if no script is loaded. " +
+			"Hex-encoded storage items prefix may be specified (empty by default to return the whole set of storage items). " +
+			"If seek prefix is not empty, then it's trimmed from the resulting keys." +
+			"Items are sorted. Backwards seek direction may be specified (false by default, which means forwards storage seek direction). " +
+			"It is possible to dump only those storage items that were added or changed during current script invocation (use --diff flag for it). " +
+			"To dump the whole set of storage changes including removed items use 'changes' command.",
+		UsageText: `storage <hash-or-address-or-id> [<prefix>] [--backwards] [--diff]`,
+		Flags: []cli.Flag{
+			cli.BoolFlag{
+				Name:  backwardsFlagFullName + ",b",
+				Usage: "Backwards traversal direction",
+			},
+			cli.BoolFlag{
+				Name:  diffFlagFullName + ",d",
+				Usage: "Dump only those storage items that were added or changed during the current script invocation. Note that this call won't show removed storage items, use 'changes' command for that.",
+			},
+		},
+		Description: `storage <hash-or-address-or-id> <prefix> [--backwards] [--diff]
+
+Dump storage of the contract with the specified hash, address or ID as is at the current stage of script invocation.
+Can be used if no script is loaded.
+Hex-encoded storage items prefix may be specified (empty by default to return the whole set of storage items).
+If seek prefix is not empty, then it's trimmed from the resulting keys.
+Items are sorted. Backwards seek direction may be specified (false by default, which means forwards storage seek direction).
+It is possible to dump only those storage items that were added or changed during current script invocation (use --diff flag for it).
+To dump the whole set of storage changes including removed items use 'changes' command.
+
+Example:
+> storage 0x0000000009070e030d0f0e020d0c06050e030c02 030e --backwards --diff`,
+		Action: handleStorage,
+	},
+	{
+		Name: "changes",
+		Usage: "Dump storage changes as is at the current stage of loaded script invocation. " +
+			"If no script is loaded or executed, then no changes are present. " +
+			"The contract hash, address or ID may be specified as the first parameter to dump the specified contract storage changes. " +
+			"Hex-encoded search prefix (without contract ID) may be specified to dump matching storage changes. " +
+			"Resulting values are not sorted.",
+		UsageText: `changes [<hash-or-address-or-id> [<prefix>]]`,
+		Description: `changes [<hash-or-address-or-id> [<prefix>]]
+
+Dump storage changes as is at the current stage of loaded script invocation.
+If no script is loaded or executed, then no changes are present.
+The contract hash, address or ID may be specified as the first parameter to dump the specified contract storage changes.
+Hex-encoded search prefix (without contract ID) may be specified to dump matching storage changes.
+Resulting values are not sorted.
+
+Example:
+> changes 0x0000000009070e030d0f0e020d0c06050e030c02 030e`,
+		Action: handleChanges,
+	},
 }
 
 var completer *readline.PrefixCompleter
@@ -243,28 +353,22 @@ var (
 	ErrInvalidParameter = errors.New("can't parse argument")
 )
 
-// VMCLI object for interacting with the VM.
+// CLI object for interacting with the VM.
-type VMCLI struct {
+type CLI struct {
-	vm    *vm.VM
+	chain *core.Blockchain
 	shell *cli.App
 }
 
-// New returns a new VMCLI object.
+// NewWithConfig returns new CLI instance using provided config and (optionally)
-func New() *VMCLI {
+// provided node config for state-backed VM.
-	return NewWithConfig(true, os.Exit, &readline.Config{
+func NewWithConfig(printLogotype bool, onExit func(int), c *readline.Config, cfg config.Config) (*CLI, error) {
-		Prompt: "\033[32mNEO-GO-VM >\033[0m ", // green prompt ^^
-	})
-}
-
-// NewWithConfig returns new VMCLI instance using provided config.
-func NewWithConfig(printLogotype bool, onExit func(int), c *readline.Config) *VMCLI {
 	if c.AutoComplete == nil {
 		// Autocomplete commands/flags on TAB.
 		c.AutoComplete = completer
 	}
 	l, err := readline.NewEx(c)
 	if err != nil {
-		panic(err)
+		return nil, fmt.Errorf("failed to create readline instance: %w", err)
 	}
 	ctl := cli.NewApp()
 	ctl.Name = "VM CLI"
@@ -284,20 +388,59 @@ func NewWithConfig(printLogotype bool, onExit func(int), c *readline.Config) *VM
 
 	ctl.Commands = commands
 
-	vmcli := VMCLI{
+	store, err := storage.NewStore(cfg.ApplicationConfiguration.DBConfiguration)
-		vm:    vm.New(),
+	if err != nil {
+		writeErr(ctl.ErrWriter, fmt.Errorf("failed to open DB, clean in-memory storage will be used: %w", err))
+		cfg.ApplicationConfiguration.DBConfiguration.Type = dbconfig.InMemoryDB
+		store = storage.NewMemoryStore()
+	}
+
+	log, logCloser, err := options.HandleLoggingParams(false, cfg.ApplicationConfiguration)
+	if err != nil {
+		return nil, cli.NewExitError(fmt.Errorf("failed to init logger: %w", err), 1)
+	}
+	filter := zap.WrapCore(func(z zapcore.Core) zapcore.Core {
+		return options.NewFilteringCore(z, func(entry zapcore.Entry) bool {
+			// Log only Runtime.Notify messages.
+			return entry.Level == zapcore.InfoLevel && entry.Message == runtime.SystemRuntimeLogMessage
+		})
+	})
+	fLog := log.WithOptions(filter)
+
+	exitF := func(i int) {
+		_ = store.Close()
+		if logCloser != nil {
+			_ = logCloser()
+		}
+		onExit(i)
+	}
+
+	chain, err := core.NewBlockchain(store, cfg.ProtocolConfiguration, fLog)
+	if err != nil {
+		return nil, cli.NewExitError(fmt.Errorf("could not initialize blockchain: %w", err), 1)
+	}
+	// Do not run chain, we need only state-related functionality from it.
+	ic, err := chain.GetTestVM(trigger.Application, nil, nil)
+	if err != nil {
+		return nil, cli.NewExitError(fmt.Errorf("failed to create test VM: %w", err), 1)
+	}
+
+	vmcli := CLI{
+		chain: chain,
 		shell: ctl,
 	}
 
 	vmcli.shell.Metadata = map[string]interface{}{
-		vmKey:               vmcli.vm,
+		chainKey:            chain,
+		chainCfgKey:         cfg,
+		icKey:               ic,
 		manifestKey:         new(manifest.Manifest),
-		exitFuncKey:         onExit,
+		exitFuncKey:         exitF,
 		readlineInstanceKey: l,
 		printLogoKey:        printLogotype,
 	}
 	changePrompt(vmcli.shell)
-	return &vmcli
+	return &vmcli, nil
 }
 
 func getExitFuncFromContext(app *cli.App) func(int) {
@@ -309,12 +452,19 @@ func getReadlineInstanceFromContext(app *cli.App) *readline.Instance {
 }
 
 func getVMFromContext(app *cli.App) *vm.VM {
-	return app.Metadata[vmKey].(*vm.VM)
+	return getInteropContextFromContext(app).VM
 }
 
-func setVMInContext(app *cli.App, v *vm.VM) {
+func getChainFromContext(app *cli.App) *core.Blockchain {
-	old := getVMFromContext(app)
+	return app.Metadata[chainKey].(*core.Blockchain)
-	*old = *v
+}
+
+func getChainConfigFromContext(app *cli.App) config.Config {
+	return app.Metadata[chainCfgKey].(config.Config)
+}
+
+func getInteropContextFromContext(app *cli.App) *interop.Context {
+	return app.Metadata[icKey].(*interop.Context)
 }
 
 func getManifestFromContext(app *cli.App) *manifest.Manifest {
@@ -325,9 +475,12 @@ func getPrintLogoFromContext(app *cli.App) bool {
 	return app.Metadata[printLogoKey].(bool)
 }
 
+func setInteropContextInContext(app *cli.App, ic *interop.Context) {
+	app.Metadata[icKey] = ic
+}
+
 func setManifestInContext(app *cli.App, m *manifest.Manifest) {
-	old := getManifestFromContext(app)
+	app.Metadata[manifestKey] = m
-	*old = *m
 }
 
 func checkVMIsReady(app *cli.App) bool {
@@ -340,6 +493,7 @@ func checkVMIsReady(app *cli.App) bool {
 }
 
 func handleExit(c *cli.Context) error {
+	finalizeInteropContext(c.App)
 	l := getReadlineInstanceFromContext(c.App)
 	_ = l.Close()
 	exit := getExitFuncFromContext(c.App)
@@ -418,7 +572,22 @@ func handleSlots(c *cli.Context) error {
 	return nil
 }
 
+// prepareVM retrieves --historic flag from context (if set) and resets app state
+// (to the specified historic height if given).
+func prepareVM(c *cli.Context) error {
+	if c.IsSet(historicFlagFullName) {
+		height := c.Int(historicFlagFullName)
+		return resetState(c.App, uint32(height))
+	}
+
+	return resetState(c.App)
+}
+
 func handleLoadNEF(c *cli.Context) error {
+	err := prepareVM(c)
+	if err != nil {
+		return err
+	}
 	v := getVMFromContext(c.App)
 	args := c.Args()
 	if len(args) < 2 {
@@ -438,6 +607,10 @@ func handleLoadNEF(c *cli.Context) error {
 }
 
 func handleLoadBase64(c *cli.Context) error {
+	err := prepareVM(c)
+	if err != nil {
+		return err
+	}
 	v := getVMFromContext(c.App)
 	args := c.Args()
 	if len(args) < 1 {
@@ -454,6 +627,10 @@ func handleLoadBase64(c *cli.Context) error {
 }
 
 func handleLoadHex(c *cli.Context) error {
+	err := prepareVM(c)
+	if err != nil {
+		return err
+	}
 	v := getVMFromContext(c.App)
 	args := c.Args()
 	if len(args) < 1 {
@@ -470,6 +647,10 @@ func handleLoadHex(c *cli.Context) error {
 }
 
 func handleLoadGo(c *cli.Context) error {
+	err := prepareVM(c)
+	if err != nil {
+		return err
+	}
 	v := getVMFromContext(c.App)
 	args := c.Args()
 	if len(args) < 1 {
@@ -496,11 +677,61 @@ func handleLoadGo(c *cli.Context) error {
 }
 
 func handleReset(c *cli.Context) error {
-	setVMInContext(c.App, vm.New())
+	err := prepareVM(c)
+	if err != nil {
+		return err
+	}
 	changePrompt(c.App)
 	return nil
 }
 
+// finalizeInteropContext calls finalizer for the current interop context.
+func finalizeInteropContext(app *cli.App) {
+	ic := getInteropContextFromContext(app)
+	ic.Finalize()
+}
+
+// resetInteropContext calls finalizer for current interop context and replaces
+// it with the newly created one.
+func resetInteropContext(app *cli.App, height ...uint32) error {
+	finalizeInteropContext(app)
+	bc := getChainFromContext(app)
+	var (
+		newIc *interop.Context
+		err   error
+	)
+	if len(height) != 0 {
+		newIc, err = bc.GetTestHistoricVM(trigger.Application, nil, height[0]+1)
+		if err != nil {
+			return fmt.Errorf("failed to create historic VM for height %d: %w", height[0], err)
+		}
+	} else {
+		newIc, err = bc.GetTestVM(trigger.Application, nil, nil)
+		if err != nil {
+			return fmt.Errorf("failed to create VM: %w", err)
+		}
+	}
+
+	setInteropContextInContext(app, newIc)
+	return nil
+}
+
+// resetManifest removes manifest from app context.
+func resetManifest(app *cli.App) {
+	setManifestInContext(app, nil)
+}
+
+// resetState resets state of the app (clear interop context and manifest) so that it's ready
+// to load new program.
+func resetState(app *cli.App, height ...uint32) error {
+	err := resetInteropContext(app, height...)
+	if err != nil {
+		return err
+	}
+	resetManifest(app)
+	return nil
+}
+
 func getManifestFromFile(name string) (*manifest.Manifest, error) {
 	bs, err := os.ReadFile(name)
 	if err != nil {
@@ -531,6 +762,9 @@ func handleRun(c *cli.Context) error {
 			return err
 		}
 		if runCurrent {
+			if m == nil {
+				return fmt.Errorf("manifest is not loaded; either use 'run' command to run loaded script from the start or use 'loadgo' and 'loadnef' commands to provide manifest")
+			}
 			md := m.ABI.GetMethod(args[0], len(params))
 			if md == nil {
 				return fmt.Errorf("%w: method not found", ErrInvalidParameter)
@@ -563,12 +797,17 @@ func runVMWithHandling(c *cli.Context) {
 		writeErr(c.App.ErrWriter, err)
 	}
 
-	var message string
+	var (
+		message string
+		dumpNtf bool
+	)
 	switch {
 	case v.HasFailed():
 		message = "" // the error will be printed on return
+		dumpNtf = true
 	case v.HasHalted():
 		message = v.DumpEStack()
+		dumpNtf = true
 	case v.AtBreakpoint():
 		ctx := v.Context()
 		if ctx.NextIP() < ctx.LenInstr() {
@@ -578,6 +817,16 @@ func runVMWithHandling(c *cli.Context) {
 			message = "execution has finished"
 		}
 	}
+	if dumpNtf {
+		var e string
+		e, err = dumpEvents(c.App)
+		if err == nil && len(e) != 0 {
+			if message != "" {
+				message += "\n"
+			}
+			message += "Events:\n" + e
+		}
+	}
 	if message != "" {
 		fmt.Fprintln(c.App.Writer, message)
 	}
@@ -670,8 +919,147 @@ func changePrompt(app *cli.App) {
 	}
 }
 
+func handleEvents(c *cli.Context) error {
+	e, err := dumpEvents(c.App)
+	if err != nil {
+		writeErr(c.App.ErrWriter, err)
+		return nil
+	}
+	fmt.Fprintln(c.App.Writer, e)
+	return nil
+}
+
+func handleEnv(c *cli.Context) error {
+	bc := getChainFromContext(c.App)
+	cfg := getChainConfigFromContext(c.App)
+	ic := getInteropContextFromContext(c.App)
+	message := fmt.Sprintf("Chain height: %d\nVM height (may differ from chain height in case of historic call): %d\nNetwork magic: %d\nDB type: %s\n",
+		bc.BlockHeight(), ic.BlockHeight(), bc.GetConfig().Magic, cfg.ApplicationConfiguration.DBConfiguration.Type)
+	if c.Bool(verboseFlagFullName) {
+		cfgBytes, err := json.MarshalIndent(cfg, "", "\t")
+		if err != nil {
+			return fmt.Errorf("failed to marshal node configuration: %w", err)
+		}
+		message += "Node config:\n" + string(cfgBytes) + "\n"
+	}
+	fmt.Fprint(c.App.Writer, message)
+	return nil
+}
+
+func handleStorage(c *cli.Context) error {
+	id, prefix, err := getDumpArgs(c)
+	if err != nil {
+		return err
+	}
+	var (
+		backwards bool
+		seekDepth int
+		ic        = getInteropContextFromContext(c.App)
+	)
+	if c.Bool(backwardsFlagFullName) {
+		backwards = true
+	}
+	if c.Bool(diffFlagFullName) {
+		seekDepth = 1 // take only upper DAO layer which stores only added or updated items.
+	}
+	ic.DAO.Seek(id, storage.SeekRange{
+		Prefix:      prefix,
+		Backwards:   backwards,
+		SearchDepth: seekDepth,
+	}, func(k, v []byte) bool {
+		fmt.Fprintf(c.App.Writer, "%s: %v\n", hex.EncodeToString(k), hex.EncodeToString(v))
+		return true
+	})
+	return nil
+}
+
+func handleChanges(c *cli.Context) error {
+	var (
+		expectedID int32
+		prefix     []byte
+		err        error
+		hasAgs     = c.Args().Present()
+	)
+	if hasAgs {
+		expectedID, prefix, err = getDumpArgs(c)
+		if err != nil {
+			return err
+		}
+	}
+	ic := getInteropContextFromContext(c.App)
+	b := ic.DAO.GetBatch()
+	if b == nil {
+		return nil
+	}
+	ops := storage.BatchToOperations(b)
+	var notFirst bool
+	for _, op := range ops {
+		id := int32(binary.LittleEndian.Uint32(op.Key))
+		if hasAgs && (expectedID != id || (len(prefix) != 0 && !bytes.HasPrefix(op.Key[4:], prefix))) {
+			continue
+		}
+		var message string
+		if notFirst {
+			message += "\n"
+		}
+		message += fmt.Sprintf("Contract ID: %d\nState: %s\nKey: %s\n", id, op.State, hex.EncodeToString(op.Key[4:]))
+		if op.Value != nil {
+			message += fmt.Sprintf("Value: %s\n", hex.EncodeToString(op.Value))
+		}
+		fmt.Fprint(c.App.Writer, message)
+		notFirst = true
+	}
+	return nil
+}
+
+// getDumpArgs is a helper function that retrieves contract ID and search prefix (if given).
+func getDumpArgs(c *cli.Context) (int32, []byte, error) {
+	if !c.Args().Present() {
+		return 0, nil, errors.New("contract hash, address or ID is mandatory argument")
+	}
+	hashOrID := c.Args().Get(0)
+	var (
+		ic     = getInteropContextFromContext(c.App)
+		id     int32
+		prefix []byte
+	)
+	h, err := flags.ParseAddress(hashOrID)
+	if err != nil {
+		i, err := strconv.ParseInt(hashOrID, 10, 32)
+		if err != nil {
+			return 0, nil, fmt.Errorf("failed to parse contract hash, address or ID: %w", err)
+		}
+		id = int32(i)
+	} else {
+		cs, err := ic.GetContract(h)
+		if err != nil {
+			return 0, nil, fmt.Errorf("contract %s not found: %w", h.StringLE(), err)
+		}
+		id = cs.ID
+	}
+	if c.NArg() > 1 {
+		prefix, err = hex.DecodeString(c.Args().Get(1))
+		if err != nil {
+			return 0, nil, fmt.Errorf("failed to decode prefix from hex: %w", err)
+		}
+	}
+	return id, prefix, nil
+}
+
+func dumpEvents(app *cli.App) (string, error) {
+	ic := getInteropContextFromContext(app)
+	if len(ic.Notifications) == 0 {
+		return "", nil
+	}
+	b, err := json.MarshalIndent(ic.Notifications, "", "\t")
+	if err != nil {
+		return "", fmt.Errorf("failed to marshal notifications: %w", err)
+	}
+	return string(b), nil
+}
+
 // Run waits for user input from Stdin and executes the passed command.
-func (c *VMCLI) Run() error {
+func (c *CLI) Run() error {
 	if getPrintLogoFromContext(c.shell) {
 		printLogo(c.shell.Writer)
 	}

cli/vm/cli_test.go

@@ -1,4 +1,4 @@
-package cli
+package vm
 
 import (
 	"bytes"
@@ -15,12 +15,20 @@ import (
 	"time"
 
 	"github.com/chzyer/readline"
+	"github.com/nspcc-dev/neo-go/internal/basicchain"
 	"github.com/nspcc-dev/neo-go/internal/random"
 	"github.com/nspcc-dev/neo-go/pkg/compiler"
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage/dboper"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
 	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/neotest"
+	"github.com/nspcc-dev/neo-go/pkg/neotest/chain"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
@@ -54,7 +62,7 @@ func (r *readCloser) WriteString(s string) {
 type executor struct {
 	in   *readCloser
 	out  *bytes.Buffer
-	cli  *VMCLI
+	cli  *CLI
 	ch   chan struct{}
 	exit atomic.Bool
 }
@@ -64,12 +72,27 @@ func newTestVMCLI(t *testing.T) *executor {
 }
 
 func newTestVMCLIWithLogo(t *testing.T, printLogo bool) *executor {
+	return newTestVMCLIWithLogoAndCustomConfig(t, printLogo, nil)
+}
+
+func newTestVMCLIWithLogoAndCustomConfig(t *testing.T, printLogo bool, cfg *config.Config) *executor {
 	e := &executor{
 		in:  &readCloser{Buffer: *bytes.NewBuffer(nil)},
 		out: bytes.NewBuffer(nil),
 		ch:  make(chan struct{}),
 	}
-	e.cli = NewWithConfig(printLogo,
+	var c config.Config
+	if cfg == nil {
+		configPath := "../../config/protocol.unit_testnet.single.yml"
+		var err error
+		c, err = config.LoadFile(configPath)
+		require.NoError(t, err, "could not load chain config")
+		c.ApplicationConfiguration.DBConfiguration.Type = dbconfig.InMemoryDB
+	} else {
+		c = *cfg
+	}
+	var err error
+	e.cli, err = NewWithConfig(printLogo,
 		func(int) { e.exit.Store(true) },
 		&readline.Config{
 			Prompt: "",
@@ -79,10 +102,40 @@ func newTestVMCLIWithLogo(t *testing.T, printLogo bool) *executor {
 			FuncIsTerminal: func() bool {
 				return false
 			},
-		})
+		}, c)
+	require.NoError(t, err)
 	return e
 }
 
+func newTestVMClIWithState(t *testing.T) *executor {
+	// Firstly create a DB with chain, save and close it.
+	path := t.TempDir()
+	opts := dbconfig.LevelDBOptions{
+		DataDirectoryPath: path,
+	}
+	store, err := storage.NewLevelDBStore(opts)
+	require.NoError(t, err)
+	customConfig := func(c *config.ProtocolConfiguration) {
+		c.StateRootInHeader = true // Need for P2PStateExchangeExtensions check.
+		c.P2PSigExtensions = true  // Need for basic chain initializer.
+	}
+	bc, validators, committee, err := chain.NewMultiWithCustomConfigAndStoreNoCheck(t, customConfig, store)
+	require.NoError(t, err)
+	go bc.Run()
+	e := neotest.NewExecutor(t, bc, validators, committee)
+	basicchain.InitSimple(t, "../../", e)
+	bc.Close()
+
+	// After that create CLI backed by created chain.
+	configPath := "../../config/protocol.unit_testnet.yml"
+	cfg, err := config.LoadFile(configPath)
+	require.NoError(t, err)
+	cfg.ApplicationConfiguration.DBConfiguration.Type = dbconfig.LevelDB
+	cfg.ApplicationConfiguration.DBConfiguration.LevelDBOptions = opts
+	cfg.ProtocolConfiguration.StateRootInHeader = true
+	return newTestVMCLIWithLogoAndCustomConfig(t, false, &cfg)
+}
+
 func (e *executor) runProg(t *testing.T, commands ...string) {
 	e.runProgWithTimeout(t, 4*time.Second, commands...)
 }
@@ -107,6 +160,12 @@ func (e *executor) checkNextLine(t *testing.T, expected string) {
 	require.Regexp(t, expected, line)
 }
 
+func (e *executor) checkNextLineExact(t *testing.T, expected string) {
+	line, err := e.out.ReadString('\n')
+	require.NoError(t, err)
+	require.Equal(t, expected, line)
+}
+
 func (e *executor) checkError(t *testing.T, expectedErr error) {
 	line, err := e.out.ReadString('\n')
 	require.NoError(t, err)
@@ -139,6 +198,50 @@ func (e *executor) checkStack(t *testing.T, items ...interface{}) {
 	require.NoError(t, err)
 }
 
+func (e *executor) checkEvents(t *testing.T, isKeywordExpected bool, events ...state.NotificationEvent) {
+	if isKeywordExpected {
+		e.checkNextLine(t, "Events:")
+	}
+	d := json.NewDecoder(e.out)
+	var actual interface{}
+	require.NoError(t, d.Decode(&actual))
+	rawActual, err := json.Marshal(actual)
+	require.NoError(t, err)
+
+	rawExpected, err := json.Marshal(events)
+	require.NoError(t, err)
+	require.JSONEq(t, string(rawExpected), string(rawActual))
+
+	// Decoder has it's own buffer, we need to return unread part to the output.
+	outRemain := e.out.String()
+	e.out.Reset()
+	_, err = gio.Copy(e.out, d.Buffered())
+	require.NoError(t, err)
+	e.out.WriteString(outRemain)
+	_, err = e.out.ReadString('\n')
+	require.NoError(t, err)
+}
+
+func (e *executor) checkStorage(t *testing.T, kvs ...storage.KeyValue) {
+	for _, kv := range kvs {
+		e.checkNextLine(t, fmt.Sprintf("%s: %s", hex.EncodeToString(kv.Key), hex.EncodeToString(kv.Value)))
+	}
+}
+
+type storageChange struct {
+	ContractID int32
+	dboper.Operation
+}
+
+func (e *executor) checkChange(t *testing.T, c storageChange) {
+	e.checkNextLine(t, fmt.Sprintf("Contract ID: %d", c.ContractID))
+	e.checkNextLine(t, fmt.Sprintf("State: %s", c.State))
+	e.checkNextLine(t, fmt.Sprintf("Key: %s", hex.EncodeToString(c.Key)))
+	if c.Value != nil {
+		e.checkNextLine(t, fmt.Sprintf("Value: %s", hex.EncodeToString(c.Value)))
+	}
+}
+
 func (e *executor) checkSlot(t *testing.T, items ...interface{}) {
 	d := json.NewDecoder(e.out)
 	var actual interface{}
@@ -251,7 +354,7 @@ go 1.17`)
 require (
 	github.com/nspcc-dev/neo-go/pkg/interop v0.0.0
 )
-replace github.com/nspcc-dev/neo-go/pkg/interop => ` + filepath.Join(wd, "../../interop") + `
+replace github.com/nspcc-dev/neo-go/pkg/interop => ` + filepath.Join(wd, "../../pkg/interop") + `
 go 1.17`)
 		require.NoError(t, os.WriteFile(filepath.Join(tmpDir, "go.mod"), goMod, os.ModePerm))
 
@@ -662,3 +765,216 @@ func TestReset(t *testing.T) {
 	e.checkNextLine(t, "")
 	e.checkError(t, fmt.Errorf("VM is not ready: no program loaded"))
 }
+
+func TestRunWithState(t *testing.T) {
+	e := newTestVMClIWithState(t)
+
+	// Ensure that state is properly loaded and on-chain contract can be called.
+	script := io.NewBufBinWriter()
+	h, err := e.cli.chain.GetContractScriptHash(1) // examples/storage/storage.go
+	require.NoError(t, err)
+	emit.AppCall(script.BinWriter, h, "put", callflag.All, 3, 3)
+	e.runProg(t,
+		"loadhex "+hex.EncodeToString(script.Bytes()),
+		"run")
+	e.checkNextLine(t, "READY: loaded 37 instructions")
+	e.checkStack(t, 3)
+}
+
+func TestRunWithHistoricState(t *testing.T) {
+	e := newTestVMClIWithState(t)
+
+	script := io.NewBufBinWriter()
+	h, err := e.cli.chain.GetContractScriptHash(1) // examples/storage/storage.go
+	require.NoError(t, err)
+	emit.AppCall(script.BinWriter, h, "get", callflag.All, 1)
+	b := script.Bytes()
+
+	e.runProg(t,
+		"loadhex "+hex.EncodeToString(b), // normal invocation
+		"run",
+		"loadhex --historic 3 "+hex.EncodeToString(b), // historic invocation, old value should be retrieved
+		"run",
+		"loadhex --historic 0 "+hex.EncodeToString(b), // historic invocation, contract is not deployed yet
+		"run",
+	)
+	e.checkNextLine(t, "READY: loaded 36 instructions")
+	e.checkStack(t, []byte{2})
+	e.checkNextLine(t, "READY: loaded 36 instructions")
+	e.checkStack(t, []byte{1})
+	e.checkNextLine(t, "READY: loaded 36 instructions")
+	e.checkNextLineExact(t, "Error: at instruction 31 (SYSCALL): failed to invoke syscall 1381727586: called contract a00e3c2643a08a452d8b0bdd31849ae11a17c445 not found: key not found\n")
+}
+
+func TestEvents(t *testing.T) {
+	e := newTestVMClIWithState(t)
+
+	script := io.NewBufBinWriter()
+	h, err := e.cli.chain.GetContractScriptHash(2) // examples/runtime/runtime.go
+	require.NoError(t, err)
+	emit.AppCall(script.BinWriter, h, "notify", callflag.All, []interface{}{true, 5})
+	e.runProg(t,
+		"loadhex "+hex.EncodeToString(script.Bytes()),
+		"run",
+		"events")
+	expectedEvent := state.NotificationEvent{
+		ScriptHash: h,
+		Name:       "Event",
+		Item: stackitem.NewArray([]stackitem.Item{
+			stackitem.NewArray([]stackitem.Item{
+				stackitem.Make(true),
+				stackitem.Make(5),
+			}),
+		}),
+	}
+	e.checkNextLine(t, "READY: loaded 44 instructions")
+	e.checkStack(t, stackitem.Null{})
+	e.checkEvents(t, true, expectedEvent)  // automatically printed after `run` command
+	e.checkEvents(t, false, expectedEvent) // printed after `events` command
+}
+
+func TestEnv(t *testing.T) {
+	t.Run("default setup", func(t *testing.T) {
+		e := newTestVMCLI(t)
+		e.runProg(t, "env")
+		e.checkNextLine(t, "Chain height: 0")
+		e.checkNextLineExact(t, "VM height (may differ from chain height in case of historic call): 0\n")
+		e.checkNextLine(t, "Network magic: 42")
+		e.checkNextLine(t, "DB type: inmemory")
+	})
+	t.Run("setup with state", func(t *testing.T) {
+		e := newTestVMClIWithState(t)
+		e.runProg(t, "env")
+		e.checkNextLine(t, "Chain height: 5")
+		e.checkNextLineExact(t, "VM height (may differ from chain height in case of historic call): 5\n")
+		e.checkNextLine(t, "Network magic: 42")
+		e.checkNextLine(t, "DB type: leveldb")
+	})
+	t.Run("setup with historic state", func(t *testing.T) {
+		e := newTestVMClIWithState(t)
+		e.runProg(t, "loadbase64 --historic 3 "+base64.StdEncoding.EncodeToString([]byte{byte(opcode.PUSH1)}),
+			"env")
+		e.checkNextLine(t, "READY: loaded 1 instructions")
+		e.checkNextLine(t, "Chain height: 5")
+		e.checkNextLineExact(t, "VM height (may differ from chain height in case of historic call): 3\n")
+		e.checkNextLine(t, "Network magic: 42")
+		e.checkNextLine(t, "DB type: leveldb")
+	})
+	t.Run("verbose", func(t *testing.T) {
+		e := newTestVMClIWithState(t)
+		e.runProg(t, "env -v")
+		e.checkNextLine(t, "Chain height: 5")
+		e.checkNextLineExact(t, "VM height (may differ from chain height in case of historic call): 5\n")
+		e.checkNextLine(t, "Network magic: 42")
+		e.checkNextLine(t, "DB type: leveldb")
+		e.checkNextLine(t, "Node config:") // Do not check exact node config.
+	})
+}
+
+func TestDumpStorage(t *testing.T) {
+	e := newTestVMClIWithState(t)
+
+	h, err := e.cli.chain.GetContractScriptHash(1) // examples/storage/storage.go
+	require.NoError(t, err)
+	expected := []storage.KeyValue{
+		{Key: []byte{1}, Value: []byte{2}},
+		{Key: []byte{2}, Value: []byte{2}},
+	}
+	e.runProg(t,
+		"storage "+h.StringLE(),
+		"storage 0x"+h.StringLE(),
+		"storage "+address.Uint160ToString(h),
+		"storage 1",
+		"storage 1 "+hex.EncodeToString(expected[0].Key),
+		"storage 1 --backwards",
+	)
+	e.checkStorage(t, expected...)
+	e.checkStorage(t, expected...)
+	e.checkStorage(t, expected...)
+	e.checkStorage(t, expected...)
+	e.checkStorage(t, storage.KeyValue{Key: nil, Value: []byte{2}}) // empty key because search prefix is trimmed
+	e.checkStorage(t, expected[1], expected[0])
+}
+
+func TestDumpStorageDiff(t *testing.T) {
+	e := newTestVMClIWithState(t)
+
+	script := io.NewBufBinWriter()
+	h, err := e.cli.chain.GetContractScriptHash(1) // examples/storage/storage.go
+	require.NoError(t, err)
+	emit.AppCall(script.BinWriter, h, "put", callflag.All, 3, 3)
+
+	expected := []storage.KeyValue{
+		{Key: []byte{1}, Value: []byte{2}},
+		{Key: []byte{2}, Value: []byte{2}},
+	}
+	diff := storage.KeyValue{Key: []byte{3}, Value: []byte{3}}
+	e.runProg(t,
+		"storage 1",
+		"storage 1 --diff",
+		"loadhex "+hex.EncodeToString(script.Bytes()),
+		"run",
+		"storage 1",
+		"storage 1 --diff",
+	)
+
+	e.checkStorage(t, expected...)
+	// no script is executed => no diff
+	e.checkNextLine(t, "READY: loaded 37 instructions")
+	e.checkStack(t, 3)
+	e.checkStorage(t, append(expected, diff)...)
+	e.checkStorage(t, diff)
+}
+
+func TestDumpChanges(t *testing.T) {
+	e := newTestVMClIWithState(t)
+
+	script := io.NewBufBinWriter()
+	h, err := e.cli.chain.GetContractScriptHash(1) // examples/storage/storage.go
+	require.NoError(t, err)
+	emit.AppCall(script.BinWriter, h, "put", callflag.All, 3, 4) // add
+	emit.AppCall(script.BinWriter, h, "delete", callflag.All, 1) // remove
+	emit.AppCall(script.BinWriter, h, "put", callflag.All, 2, 5) // update
+
+	expected := []storageChange{
+		{
+			ContractID: 1,
+			Operation: dboper.Operation{
+				State: "Deleted",
+				Key:   []byte{1},
+			},
+		},
+		{
+			ContractID: 1,
+			Operation: dboper.Operation{
+				State: "Changed",
+				Key:   []byte{2},
+				Value: []byte{5},
+			},
+		},
+		{
+			ContractID: 1,
+			Operation: dboper.Operation{
+				State: "Added",
+				Key:   []byte{3},
+				Value: []byte{4},
+			},
+		},
+	}
+	e.runProg(t,
+		"changes",
+		"changes 1",
+		"loadhex "+hex.EncodeToString(script.Bytes()),
+		"run",
+		"changes 1 "+hex.EncodeToString([]byte{1}),
+		"changes 1 "+hex.EncodeToString([]byte{2}),
+		"changes 1 "+hex.EncodeToString([]byte{3}),
+	)
+
+	// no script is executed => no diff
+	e.checkNextLine(t, "READY: loaded 113 instructions")
+	e.checkStack(t, 3, true, 2)
+	e.checkChange(t, expected[0])
+	e.checkChange(t, expected[1])
+	e.checkChange(t, expected[2])
+}

cli/vm/vm.go

@@ -1,23 +1,25 @@
 package vm
 
 import (
+	"fmt"
 	"os"
 
 	"github.com/chzyer/readline"
 	"github.com/nspcc-dev/neo-go/cli/cmdargs"
-	vmcli "github.com/nspcc-dev/neo-go/pkg/vm/cli"
+	"github.com/nspcc-dev/neo-go/cli/options"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
 	"github.com/urfave/cli"
 )
 
 // NewCommands returns 'vm' command.
 func NewCommands() []cli.Command {
+	cfgFlags := []cli.Flag{options.Config}
+	cfgFlags = append(cfgFlags, options.Network...)
 	return []cli.Command{{
 		Name:   "vm",
 		Usage:  "start the virtual machine",
 		Action: startVMPrompt,
-		Flags: []cli.Flag{
+		Flags:  cfgFlags,
-			cli.BoolFlag{Name: "debug, d"},
-		},
 	}}
 }
 
@@ -25,6 +27,22 @@ func startVMPrompt(ctx *cli.Context) error {
 	if err := cmdargs.EnsureNone(ctx); err != nil {
 		return err
 	}
-	p := vmcli.NewWithConfig(true, os.Exit, &readline.Config{})
+
+	cfg, err := options.GetConfigFromContext(ctx)
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+	if ctx.NumFlags() == 0 {
+		cfg.ApplicationConfiguration.DBConfiguration.Type = dbconfig.InMemoryDB
+	}
+	if cfg.ApplicationConfiguration.DBConfiguration.Type != dbconfig.InMemoryDB {
+		cfg.ApplicationConfiguration.DBConfiguration.LevelDBOptions.ReadOnly = true
+		cfg.ApplicationConfiguration.DBConfiguration.BoltDBOptions.ReadOnly = true
+	}
+
+	p, err := NewWithConfig(true, os.Exit, &readline.Config{}, cfg)
+	if err != nil {
+		return cli.NewExitError(fmt.Errorf("failed to create VM CLI: %w", err), 1)
+	}
 	return p.Run()
 }

docs/node-configuration.md

@@ -47,14 +47,20 @@ DBConfiguration:
   Type: leveldb
   LevelDBOptions:
     DataDirectoryPath: /chains/privnet
+    ReadOnly: false
   BoltDBOptions:
     FilePath: ./chains/privnet.bolt
+    ReadOnly: false
 ```
 where:
-- `Type` is the database type (string value). Supported types: `levelDB` and
+- `Type` is the database type (string value). Supported types: `leveldb`, `boltdb` and
-  `boltDB`.
+  `inmemory` (not recommended for production usage).
-- `LevelDBOptions` are settings for LevelDB.
+- `LevelDBOptions` are settings for LevelDB. Includes the DB files path and ReadOnly mode toggle.
-- `BoltDBOptions` configures BoltDB.
+  If ReadOnly mode is on, then an error will be returned on attempt to connect to unexisting or empty
+  database. Database doesn't allow changes in this mode, a warning will be logged on DB persist attempts.
+- `BoltDBOptions` configures BoltDB. Includes the DB files path and ReadOnly mode toggle. If ReadOnly
+  mode is on, then an error will be returned on attempt to connect with unexisting or empty database.
+  Database doesn't allow changes in this mode, a warning will be logged on DB persist attempts.
 
 Only options for the specified database type will be used.
 

internal/basicchain/basic.go

@@ -23,6 +23,39 @@ import (
 
 const neoAmount = 99999000
 
+// InitSimple initializes chain with simple contracts from 'examples'  folder.
+// It's not as complicated as chain got after Init and may be used for tests where
+// chain with a small amount of data is needed and for historical functionality testing.
+// Needs a path to the root directory.
+func InitSimple(t *testing.T, rootpath string, e *neotest.Executor) {
+	// examplesPrefix is a prefix of the example smart-contracts.
+	var examplesPrefix = filepath.Join(rootpath, "examples")
+
+	deployExample := func(t *testing.T, name string) util.Uint160 {
+		_, h := newDeployTx(t, e, e.Validator,
+			filepath.Join(examplesPrefix, name, name+".go"),
+			filepath.Join(examplesPrefix, name, name+".yml"),
+			true)
+		return h
+	}
+
+	// Block #1: deploy storage contract (examples/storage/storage.go).
+	storageHash := deployExample(t, "storage")
+	storageValidatorInvoker := e.ValidatorInvoker(storageHash)
+
+	// Block #2: put (1, 1) kv pair.
+	storageValidatorInvoker.Invoke(t, 1, "put", 1, 1)
+
+	// Block #3: put (2, 2) kv pair.
+	storageValidatorInvoker.Invoke(t, 2, "put", 2, 2)
+
+	// Block #4: update (1, 1) -> (1, 2).
+	storageValidatorInvoker.Invoke(t, 1, "put", 1, 2)
+
+	// Block #5: deploy runtime contract (examples/runtime/runtime.go).
+	_ = deployExample(t, "runtime")
+}
+
 // Init pushes some predefined set  of transactions into the given chain, it needs a path to
 // the root project directory.
 func Init(t *testing.T, rootpath string, e *neotest.Executor) {

internal/fakechain/fakechain.go

@@ -298,7 +298,7 @@ func (chain *FakeChain) GetStorageItem(id int32, key []byte) state.StorageItem {
 }
 
 // GetTestVM implements the Blockchainer interface.
-func (chain *FakeChain) GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) *interop.Context {
+func (chain *FakeChain) GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) (*interop.Context, error) {
 	panic("TODO")
 }
 

pkg/core/blockchain.go

@@ -55,6 +55,7 @@ const (
 	defaultMaxBlockSystemFee               = 900000000000
 	defaultMaxTraceableBlocks              = 2102400 // 1 year of 15s blocks
 	defaultMaxTransactionsPerBlock         = 512
+	defaultSecondsPerBlock                 = 15
 	// HeaderVerificationGasLimit is the maximum amount of GAS for block header verification.
 	HeaderVerificationGasLimit = 3_00000000 // 3 GAS
 	defaultStateSyncInterval   = 40000
@@ -245,6 +246,11 @@ func NewBlockchain(s storage.Store, cfg config.ProtocolConfiguration, log *zap.L
 		log.Info("MaxTransactionsPerBlock is not set or wrong, using default value",
 			zap.Uint16("MaxTransactionsPerBlock", cfg.MaxTransactionsPerBlock))
 	}
+	if cfg.SecondsPerBlock == 0 {
+		cfg.SecondsPerBlock = defaultSecondsPerBlock
+		log.Info("SecondsPerBlock is not set or wrong, using default value",
+			zap.Int("SecondsPerBlock", cfg.SecondsPerBlock))
+	}
 	if cfg.MaxValidUntilBlockIncrement == 0 {
 		const secondsPerDay = int(24 * time.Hour / time.Second)
 
@@ -2235,19 +2241,28 @@ func (bc *Blockchain) GetEnrollments() ([]state.Validator, error) {
 }
 
 // GetTestVM returns an interop context with VM set up for a test run.
-func (bc *Blockchain) GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) *interop.Context {
+func (bc *Blockchain) GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) (*interop.Context, error) {
+	if b == nil {
+		var err error
+		h := bc.BlockHeight() + 1
+		b, err = bc.getFakeNextBlock(h)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create fake block for height %d: %w", h, err)
+		}
+	}
 	systemInterop := bc.newInteropContext(t, bc.dao, b, tx)
 	_ = systemInterop.SpawnVM() // All the other code suppose that the VM is ready.
-	return systemInterop
+	return systemInterop, nil
 }
 
 // GetTestHistoricVM returns an interop context with VM set up for a test run.
-func (bc *Blockchain) GetTestHistoricVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) (*interop.Context, error) {
+func (bc *Blockchain) GetTestHistoricVM(t trigger.Type, tx *transaction.Transaction, nextBlockHeight uint32) (*interop.Context, error) {
 	if bc.config.KeepOnlyLatestState {
 		return nil, errors.New("only latest state is supported")
 	}
-	if b == nil {
+	b, err := bc.getFakeNextBlock(nextBlockHeight)
-		return nil, errors.New("block is mandatory to produce test historic VM")
+	if err != nil {
+		return nil, fmt.Errorf("failed to create fake block for height %d: %w", nextBlockHeight, err)
 	}
 	var mode = mpt.ModeAll
 	if bc.config.RemoveUntraceableBlocks {
@@ -2278,6 +2293,18 @@ func (bc *Blockchain) GetTestHistoricVM(t trigger.Type, tx *transaction.Transact
 	return systemInterop, nil
 }
 
+// getFakeNextBlock returns fake block with the specified index and pre-filled Timestamp field.
+func (bc *Blockchain) getFakeNextBlock(nextBlockHeight uint32) (*block.Block, error) {
+	b := block.New(bc.config.StateRootInHeader)
+	b.Index = nextBlockHeight
+	hdr, err := bc.GetHeader(bc.GetHeaderHash(int(nextBlockHeight - 1)))
+	if err != nil {
+		return nil, err
+	}
+	b.Timestamp = hdr.Timestamp + uint64(bc.config.SecondsPerBlock*int(time.Second/time.Millisecond))
+	return b, nil
+}
+
 // Various witness verification errors.
 var (
 	ErrWitnessHashMismatch         = errors.New("witness hash mismatch")

pkg/core/interop/contract/call_test.go

@@ -32,7 +32,8 @@ var pathToInternalContracts = filepath.Join("..", "..", "..", "..", "internal",
 
 func TestGetCallFlags(t *testing.T) {
 	bc, _ := chain.NewSingle(t)
-	ic := bc.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})
+	ic, err := bc.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})
+	require.NoError(t, err)
 
 	ic.VM.LoadScriptWithHash([]byte{byte(opcode.RET)}, util.Uint160{1, 2, 3}, callflag.All)
 	require.NoError(t, contract.GetCallFlags(ic))
@@ -41,7 +42,8 @@ func TestGetCallFlags(t *testing.T) {
 
 func TestCall(t *testing.T) {
 	bc, _ := chain.NewSingle(t)
-	ic := bc.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})
+	ic, err := bc.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})
+	require.NoError(t, err)
 
 	cs, currCs := contracts.GetTestContractState(t, pathToInternalContracts, 4, 5, random.Uint160()) // sender and IDs are not important for the test
 	require.NoError(t, native.PutContractState(ic.DAO, cs))

pkg/core/interop/runtime/engine.go

@@ -19,6 +19,9 @@ const (
 	MaxEventNameLen = 32
 	// MaxNotificationSize is the maximum length of a runtime log message.
 	MaxNotificationSize = 1024
+	// SystemRuntimeLogMessage represents log entry message used for output
+	// of the System.Runtime.Log syscall.
+	SystemRuntimeLogMessage = "runtime log"
 )
 
 // GetExecutingScriptHash returns executing script hash.
@@ -112,7 +115,7 @@ func Log(ic *interop.Context) error {
 	if ic.Tx != nil {
 		txHash = ic.Tx.Hash().StringLE()
 	}
-	ic.Log.Info("runtime log",
+	ic.Log.Info(SystemRuntimeLogMessage,
 		zap.String("tx", txHash),
 		zap.String("script", ic.VM.GetCurrentScriptHash().StringLE()),
 		zap.String("msg", state))

pkg/core/interop/runtime/ext_test.go

@@ -65,7 +65,8 @@ func getSharpTestGenesis(t *testing.T) *block.Block {
 
 func createVM(t testing.TB) (*vm.VM, *interop.Context, *core.Blockchain) {
 	chain, _ := chain.NewSingle(t)
-	ic := chain.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})
+	ic, err := chain.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})
+	require.NoError(t, err)
 	v := ic.SpawnVM()
 	return v, ic, chain
 }
@@ -523,7 +524,8 @@ func TestGetRandomCompatibility(t *testing.T) {
 
 	b := getSharpTestGenesis(t)
 	tx := getSharpTestTx(util.Uint160{})
-	ic := bc.GetTestVM(trigger.Application, tx, b)
+	ic, err := bc.GetTestVM(trigger.Application, tx, b)
+	require.NoError(t, err)
 	ic.Network = 860833102 // Old mainnet magic used by C# tests.
 
 	ic.VM = vm.New()
@@ -550,7 +552,8 @@ func TestNotify(t *testing.T) {
 	caller := random.Uint160()
 	newIC := func(name string, args interface{}) *interop.Context {
 		_, _, bc, cs := getDeployedInternal(t)
-		ic := bc.GetTestVM(trigger.Application, nil, nil)
+		ic, err := bc.GetTestVM(trigger.Application, nil, nil)
+		require.NoError(t, err)
 		ic.VM.LoadNEFMethod(&cs.NEF, caller, cs.Hash, callflag.NoneFlag, true, 0, -1, nil)
 		ic.VM.Estack().PushVal(args)
 		ic.VM.Estack().PushVal(name)

pkg/core/interop/storage/storage_test.go

@@ -300,7 +300,8 @@ func TestFind(t *testing.T) {
 
 func createVM(t testing.TB) (*vm.VM, *interop.Context, *core.Blockchain) {
 	chain, _ := chain.NewSingle(t)
-	ic := chain.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})
+	ic, err := chain.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})
+	require.NoError(t, err)
 	v := ic.SpawnVM()
 	return v, ic, chain
 }

pkg/core/native/invocation_test.go

@@ -74,7 +74,8 @@ func TestNativeContract_InvokeInternal(t *testing.T) {
 	require.NotNil(t, md)
 
 	t.Run("fail, bad current script hash", func(t *testing.T) {
-		ic := bc.GetTestVM(trigger.Application, nil, nil)
+		ic, err := bc.GetTestVM(trigger.Application, nil, nil)
+		require.NoError(t, err)
 		v := ic.SpawnVM()
 		fakeH := util.Uint160{1, 2, 3}
 		v.LoadScriptWithHash(clState.NEF.Script, fakeH, callflag.All)
@@ -83,7 +84,7 @@ func TestNativeContract_InvokeInternal(t *testing.T) {
 		v.Context().Jump(md.Offset)
 
 		// Bad current script hash
-		err := v.Run()
+		err = v.Run()
 		require.Error(t, err)
 		require.True(t, strings.Contains(err.Error(), fmt.Sprintf("native contract %s (version 0) not found", fakeH.StringLE())), err.Error())
 	})
@@ -104,7 +105,8 @@ func TestNativeContract_InvokeInternal(t *testing.T) {
 		})
 		eBad := neotest.NewExecutor(t, bcBad, validatorBad, committeeBad)
 
-		ic := bcBad.GetTestVM(trigger.Application, nil, nil)
+		ic, err := bcBad.GetTestVM(trigger.Application, nil, nil)
+		require.NoError(t, err)
 		v := ic.SpawnVM()
 		v.LoadScriptWithHash(clState.NEF.Script, clState.Hash, callflag.All) // hash is not affected by native update history
 		input := []byte{1, 2, 3, 4}
@@ -112,13 +114,14 @@ func TestNativeContract_InvokeInternal(t *testing.T) {
 		v.Context().Jump(md.Offset)
 
 		// It's prohibited to call natives before NativeUpdateHistory[0] height.
-		err := v.Run()
+		err = v.Run()
 		require.Error(t, err)
 		require.True(t, strings.Contains(err.Error(), "native contract CryptoLib is active after height = 1"))
 
 		// Add new block => CryptoLib should be active now.
 		eBad.AddNewBlock(t)
-		ic = bcBad.GetTestVM(trigger.Application, nil, nil)
+		ic, err = bcBad.GetTestVM(trigger.Application, nil, nil)
+		require.NoError(t, err)
 		v = ic.SpawnVM()
 		v.LoadScriptWithHash(clState.NEF.Script, clState.Hash, callflag.All) // hash is not affected by native update history
 		v.Estack().PushVal(input)
@@ -130,7 +133,8 @@ func TestNativeContract_InvokeInternal(t *testing.T) {
 	})
 
 	t.Run("success", func(t *testing.T) {
-		ic := bc.GetTestVM(trigger.Application, nil, nil)
+		ic, err := bc.GetTestVM(trigger.Application, nil, nil)
+		require.NoError(t, err)
 		v := ic.SpawnVM()
 		v.LoadScriptWithHash(clState.NEF.Script, clState.Hash, callflag.All)
 		input := []byte{1, 2, 3, 4}

pkg/core/native/native_test/management_test.go

@@ -288,7 +288,7 @@ func TestManagement_StartFromHeight(t *testing.T) {
 	// Create database to be able to start another chain from the same height later.
 	ldbDir := t.TempDir()
 	dbConfig := dbconfig.DBConfiguration{
-		Type: "leveldb",
+		Type: dbconfig.LevelDB,
 		LevelDBOptions: dbconfig.LevelDBOptions{
 			DataDirectoryPath: ldbDir,
 		},

pkg/core/storage/boltdb_store.go

@@ -2,6 +2,7 @@ package storage
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"os"
 
@@ -22,23 +23,41 @@ type BoltDBStore struct {
 
 // NewBoltDBStore returns a new ready to use BoltDB storage with created bucket.
 func NewBoltDBStore(cfg dbconfig.BoltDBOptions) (*BoltDBStore, error) {
-	var opts *bbolt.Options       // should be exposed via BoltDBOptions if anything needed
+	cp := *bbolt.DefaultOptions // Do not change bbolt's global variable.
+	opts := &cp
 	fileMode := os.FileMode(0600) // should be exposed via BoltDBOptions if anything needed
 	fileName := cfg.FilePath
-	if err := io.MakeDirForFile(fileName, "BoltDB"); err != nil {
+	if cfg.ReadOnly {
-		return nil, err
+		opts.ReadOnly = true
+	} else {
+		if err := io.MakeDirForFile(fileName, "BoltDB"); err != nil {
+			return nil, err
+		}
 	}
 	db, err := bbolt.Open(fileName, fileMode, opts)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to open BoltDB instance: %w", err)
+	}
+	if opts.ReadOnly {
+		err = db.View(func(tx *bbolt.Tx) error {
+			b := tx.Bucket(Bucket)
+			if b == nil {
+				return errors.New("root bucket does not exist")
+			}
+			return nil
+		})
+	} else {
+		err = db.Update(func(tx *bbolt.Tx) error {
+			_, err = tx.CreateBucketIfNotExists(Bucket)
+			if err != nil {
+				return fmt.Errorf("could not create root bucket: %w", err)
+			}
+			return nil
+		})
+	}
+	if err != nil {
+		return nil, fmt.Errorf("failed to initialize BoltDB instance: %w", err)
 	}
-	err = db.Update(func(tx *bbolt.Tx) error {
-		_, err = tx.CreateBucketIfNotExists(Bucket)
-		if err != nil {
-			return fmt.Errorf("could not create root bucket: %w", err)
-		}
-		return nil
-	})
 
 	return &BoltDBStore{db: db}, nil
 }

pkg/core/storage/boltdb_store_test.go

@@ -1,11 +1,15 @@
 package storage
 
 import (
+	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
+	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/stretchr/testify/require"
+	"go.etcd.io/bbolt"
 )
 
 func newBoltStoreForTesting(t testing.TB) Store {
@@ -15,3 +19,42 @@ func newBoltStoreForTesting(t testing.TB) Store {
 	require.NoError(t, err)
 	return boltDBStore
 }
+
+func TestROBoltDB(t *testing.T) {
+	d := t.TempDir()
+	testFileName := filepath.Join(d, "test_ro_bolt_db")
+	cfg := dbconfig.BoltDBOptions{
+		FilePath: testFileName,
+		ReadOnly: true,
+	}
+
+	// If DB doesn't exist, then error should be returned.
+	_, err := NewBoltDBStore(cfg)
+	require.Error(t, err)
+
+	// Create the DB and try to open it in RO mode.
+	cfg.ReadOnly = false
+	store, err := NewBoltDBStore(cfg)
+	require.NoError(t, err)
+	require.NoError(t, store.Close())
+	cfg.ReadOnly = true
+
+	store, err = NewBoltDBStore(cfg)
+	require.NoError(t, err)
+	// Changes must be prohibited.
+	putErr := store.PutChangeSet(map[string][]byte{"one": []byte("one")}, nil)
+	require.ErrorIs(t, putErr, bbolt.ErrDatabaseReadOnly)
+	require.NoError(t, store.Close())
+
+	// Create the DB without buckets and try to open it in RO mode, an error is expected.
+	fileMode := os.FileMode(0600)
+	cfg.FilePath = filepath.Join(d, "clean_ro_bolt_db")
+	require.NoError(t, io.MakeDirForFile(cfg.FilePath, "BoltDB"))
+	db, err := bbolt.Open(cfg.FilePath, fileMode, nil)
+	require.NoError(t, err)
+	require.NoError(t, db.Close())
+
+	_, err = NewBoltDBStore(cfg)
+	require.Error(t, err)
+	require.True(t, strings.Contains(err.Error(), "root bucket does not exist"))
+}

pkg/core/storage/dbconfig/store_config.go

@@ -13,9 +13,11 @@ type (
 	// LevelDBOptions configuration for LevelDB.
 	LevelDBOptions struct {
 		DataDirectoryPath string `yaml:"DataDirectoryPath"`
+		ReadOnly          bool   `yaml:"ReadOnly"`
 	}
 	// BoltDBOptions configuration for BoltDB.
 	BoltDBOptions struct {
 		FilePath string `yaml:"FilePath"`
+		ReadOnly bool   `yaml:"ReadOnly"`
 	}
 )

pkg/core/storage/dbconfig/store_type.go

@@ -0,0 +1,11 @@
+package dbconfig
+
+// Available storage types.
+const (
+	// BoltDB represents Bolt DB storage name.
+	BoltDB = "boltdb"
+	// LevelDB represents Level DB storage name.
+	LevelDB = "leveldb"
+	// InMemoryDB represents in-memory storage name.
+	InMemoryDB = "inmemory"
+)

pkg/core/storage/leveldb_store.go

@@ -2,6 +2,7 @@ package storage
 
 import (
 	"errors"
+	"fmt"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
 	"github.com/syndtr/goleveldb/leveldb"
@@ -21,11 +22,14 @@ type LevelDBStore struct {
 // initialize the database found at the given path.
 func NewLevelDBStore(cfg dbconfig.LevelDBOptions) (*LevelDBStore, error) {
 	var opts = new(opt.Options) // should be exposed via LevelDBOptions if anything needed
-
+	if cfg.ReadOnly {
+		opts.ReadOnly = true
+		opts.ErrorIfMissing = true
+	}
 	opts.Filter = filter.NewBloomFilter(10)
 	db, err := leveldb.OpenFile(cfg.DataDirectoryPath, opts)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to open LevelDB instance: %w", err)
 	}
 
 	return &LevelDBStore{

pkg/core/storage/leveldb_store_test.go

@@ -5,17 +5,41 @@ import (
 
 	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
 	"github.com/stretchr/testify/require"
+	"github.com/syndtr/goleveldb/leveldb"
 )
 
 func newLevelDBForTesting(t testing.TB) Store {
 	ldbDir := t.TempDir()
-	dbConfig := dbconfig.DBConfiguration{
+	opts := dbconfig.LevelDBOptions{
-		Type: "leveldb",
+		DataDirectoryPath: ldbDir,
-		LevelDBOptions: dbconfig.LevelDBOptions{
-			DataDirectoryPath: ldbDir,
-		},
 	}
-	newLevelStore, err := NewLevelDBStore(dbConfig.LevelDBOptions)
+	newLevelStore, err := NewLevelDBStore(opts)
 	require.Nil(t, err, "NewLevelDBStore error")
 	return newLevelStore
 }
+
+func TestROLevelDB(t *testing.T) {
+	ldbDir := t.TempDir()
+	opts := dbconfig.LevelDBOptions{
+		DataDirectoryPath: ldbDir,
+		ReadOnly:          true,
+	}
+
+	// If DB doesn't exist, then error should be returned.
+	_, err := NewLevelDBStore(opts)
+	require.Error(t, err)
+
+	// Create the DB and try to open it in RO mode.
+	opts.ReadOnly = false
+	store, err := NewLevelDBStore(opts)
+	require.NoError(t, err)
+	require.NoError(t, store.Close())
+	opts.ReadOnly = true
+
+	store, err = NewLevelDBStore(opts)
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, store.Close()) })
+	// Changes must be prohibited.
+	putErr := store.PutChangeSet(map[string][]byte{"one": []byte("one")}, nil)
+	require.ErrorIs(t, putErr, leveldb.ErrReadOnly)
+}

pkg/core/storage/memcached_store.go

@@ -301,7 +301,12 @@ func performSeek(ctx context.Context, ps Store, memRes []KeyValueExists, rng See
 			}
 		}
 	}
-	ps.Seek(rng, mergeFunc)
+	if rng.SearchDepth == 0 || rng.SearchDepth > 1 {
+		if rng.SearchDepth > 1 {
+			rng.SearchDepth--
+		}
+		ps.Seek(rng, mergeFunc)
+	}
 
 	if !done && haveMem {
 	loop:

pkg/core/storage/store.go

@@ -59,6 +59,11 @@ type SeekRange struct {
 	// whether seeking should be performed in a descending way.
 	// Backwards can be safely combined with Prefix and Start.
 	Backwards bool
+	// SearchDepth is the depth of Seek operation, denotes the number of cached
+	// DAO layers to perform search. Use 1 to fetch the latest changes from upper
+	// in-memory layer of cached DAO. Default 0 value denotes searching through
+	// the whole set of cached layers.
+	SearchDepth int
 }
 
 // ErrKeyNotFound is an error returned by Store implementations
@@ -114,11 +119,11 @@ func NewStore(cfg dbconfig.DBConfiguration) (Store, error) {
 	var store Store
 	var err error
 	switch cfg.Type {
-	case "leveldb":
+	case dbconfig.LevelDB:
 		store, err = NewLevelDBStore(cfg.LevelDBOptions)
-	case "inmemory":
+	case dbconfig.InMemoryDB:
 		store = NewMemoryStore()
-	case "boltdb":
+	case dbconfig.BoltDB:
 		store, err = NewBoltDBStore(cfg.BoltDBOptions)
 	default:
 		return nil, fmt.Errorf("unknown storage: %s", cfg.Type)

pkg/core/storage/store_type_test.go

@@ -0,0 +1,29 @@
+package storage
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
+	"github.com/stretchr/testify/require"
+)
+
+func TestStorageNames(t *testing.T) {
+	tmp := t.TempDir()
+	cfg := dbconfig.DBConfiguration{
+		LevelDBOptions: dbconfig.LevelDBOptions{
+			DataDirectoryPath: filepath.Join(tmp, "level"),
+		},
+		BoltDBOptions: dbconfig.BoltDBOptions{
+			FilePath: filepath.Join(tmp, "bolt"),
+		},
+	}
+	for _, name := range []string{dbconfig.BoltDB, dbconfig.LevelDB, dbconfig.InMemoryDB} {
+		t.Run(name, func(t *testing.T) {
+			cfg.Type = name
+			s, err := NewStore(cfg)
+			require.NoError(t, err)
+			require.NoError(t, s.Close())
+		})
+	}
+}

pkg/neotest/basic.go

@@ -374,7 +374,8 @@ func TestInvoke(bc *core.Blockchain, tx *transaction.Transaction) (*vm.VM, error
 	// `GetTestVM` as well as `Run` can use a transaction hash which will set a cached value.
 	// This is unwanted behavior, so we explicitly copy the transaction to perform execution.
 	ttx := *tx
-	ic := bc.GetTestVM(trigger.Application, &ttx, b)
+	ic, _ := bc.GetTestVM(trigger.Application, &ttx, b)
+
 	defer ic.Finalize()
 
 	ic.VM.LoadWithFlags(tx.Script, callflag.All)

pkg/neotest/client.go

@@ -51,11 +51,14 @@ func (e *Executor) ValidatorInvoker(h util.Uint160) *ContractInvoker {
 func (c *ContractInvoker) TestInvoke(t testing.TB, method string, args ...interface{}) (*vm.Stack, error) {
 	tx := c.PrepareInvokeNoSign(t, method, args...)
 	b := c.NewUnsignedBlock(t, tx)
-	ic := c.Chain.GetTestVM(trigger.Application, tx, b)
+	ic, err := c.Chain.GetTestVM(trigger.Application, tx, b)
+	if err != nil {
+		return nil, err
+	}
 	t.Cleanup(ic.Finalize)
 
 	ic.VM.LoadWithFlags(tx.Script, callflag.All)
-	err := ic.VM.Run()
+	err = ic.VM.Run()
 	return ic.VM.Estack(), err
 }
 

pkg/services/oracle/oracle.go

@@ -29,7 +29,7 @@ type (
 		GetBaseExecFee() int64
 		GetConfig() config.ProtocolConfiguration
 		GetMaxVerificationGAS() int64
-		GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) *interop.Context
+		GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) (*interop.Context, error)
 		GetTransaction(util.Uint256) (*transaction.Transaction, uint32, error)
 	}
 

pkg/services/oracle/response.go

@@ -3,6 +3,7 @@ package oracle
 import (
 	"encoding/hex"
 	"errors"
+	"fmt"
 	gio "io"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/fee"
@@ -107,7 +108,10 @@ func (o *Oracle) CreateResponseTx(gasForResponse int64, vub uint32, resp *transa
 	size := io.GetVarSize(tx)
 	tx.Scripts = append(tx.Scripts, transaction.Witness{VerificationScript: oracleSignContract})
 
-	gasConsumed, ok := o.testVerify(tx)
+	gasConsumed, ok, err := o.testVerify(tx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to prepare `verify` invocation: %w", err)
+	}
 	if !ok {
 		return nil, errors.New("can't verify transaction")
 	}
@@ -131,18 +135,21 @@ func (o *Oracle) CreateResponseTx(gasForResponse int64, vub uint32, resp *transa
 	return tx, nil
 }
 
-func (o *Oracle) testVerify(tx *transaction.Transaction) (int64, bool) {
+func (o *Oracle) testVerify(tx *transaction.Transaction) (int64, bool, error) {
 	// (*Blockchain).GetTestVM calls Hash() method of the provided transaction; once being called, this
 	// method caches transaction hash, but tx building is not yet completed and hash will be changed.
 	// So, make a copy of the tx to avoid wrong hash caching.
 	cp := *tx
-	ic := o.Chain.GetTestVM(trigger.Verification, &cp, nil)
+	ic, err := o.Chain.GetTestVM(trigger.Verification, &cp, nil)
+	if err != nil {
+		return 0, false, fmt.Errorf("failed to create test VM: %w", err)
+	}
 	ic.VM.GasLimit = o.Chain.GetMaxVerificationGAS()
 	ic.VM.LoadScriptWithHash(o.oracleScript, o.oracleHash, callflag.ReadOnly)
 	ic.VM.Context().Jump(o.verifyOffset)
 
 	ok := isVerifyOk(ic)
-	return ic.VM.GasConsumed(), ok
+	return ic.VM.GasConsumed(), ok, nil
 }
 
 func isVerifyOk(ic *interop.Context) bool {

pkg/services/rpcsrv/client_test.go

@@ -1181,7 +1181,8 @@ func TestCreateNEP17TransferTx(t *testing.T) {
 		require.NoError(t, err)
 		require.NoError(t, acc.SignTx(testchain.Network(), tx))
 		require.NoError(t, chain.VerifyTx(tx))
-		ic := chain.GetTestVM(trigger.Application, tx, nil)
+		ic, err := chain.GetTestVM(trigger.Application, tx, nil)
+		require.NoError(t, err)
 		ic.VM.LoadScriptWithFlags(tx.Script, callflag.All)
 		require.NoError(t, ic.VM.Run())
 	})
@@ -1195,7 +1196,8 @@ func TestCreateNEP17TransferTx(t *testing.T) {
 		})
 		require.NoError(t, err)
 		require.NoError(t, chain.VerifyTx(tx))
-		ic := chain.GetTestVM(trigger.Application, tx, nil)
+		ic, err := chain.GetTestVM(trigger.Application, tx, nil)
+		require.NoError(t, err)
 		ic.VM.LoadScriptWithFlags(tx.Script, callflag.All)
 		require.NoError(t, ic.VM.Run())
 		require.Equal(t, 2, len(ic.Notifications))
@@ -1228,7 +1230,8 @@ func TestCreateNEP17TransferTx(t *testing.T) {
 		require.NoError(t, err)
 		require.NoError(t, acc.SignTx(testchain.Network(), tx))
 		require.NoError(t, chain.VerifyTx(tx))
-		ic := chain.GetTestVM(trigger.Application, tx, nil)
+		ic, err := chain.GetTestVM(trigger.Application, tx, nil)
+		require.NoError(t, err)
 		ic.VM.LoadScriptWithFlags(tx.Script, callflag.All)
 		require.NoError(t, ic.VM.Run())
 	})

pkg/services/rpcsrv/server.go

@@ -89,8 +89,8 @@ type (
 		GetNotaryServiceFeePerKey() int64
 		GetStateModule() core.StateRoot
 		GetStorageItem(id int32, key []byte) state.StorageItem
-		GetTestHistoricVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) (*interop.Context, error)
+		GetTestHistoricVM(t trigger.Type, tx *transaction.Transaction, nextBlockHeight uint32) (*interop.Context, error)
-		GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) *interop.Context
+		GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) (*interop.Context, error)
 		GetTokenLastUpdated(acc util.Uint160) (map[int32]uint32, error)
 		GetTransaction(util.Uint256) (*transaction.Transaction, uint32, error)
 		GetValidators() ([]*keys.PublicKey, error)
@@ -1065,11 +1065,10 @@ func (s *Server) invokeReadOnlyMulti(bw *io.BufBinWriter, h util.Uint160, method
 	}
 	script := bw.Bytes()
 	tx := &transaction.Transaction{Script: script}
-	b, err := s.getFakeNextBlock(s.chain.BlockHeight() + 1)
+	ic, err := s.chain.GetTestVM(trigger.Application, tx, nil)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("faile to prepare test VM: %w", err)
 	}
-	ic := s.chain.GetTestVM(trigger.Application, tx, b)
 	ic.VM.GasLimit = core.HeaderVerificationGasLimit
 	ic.VM.LoadScriptWithFlags(script, callflag.All)
 	err = ic.VM.Run()
@@ -1832,7 +1831,7 @@ func (s *Server) invokeFunction(reqParams params.Params) (interface{}, *neorpc.E
 
 // invokeFunctionHistoric implements the `invokeFunctionHistoric` RPC call.
 func (s *Server) invokeFunctionHistoric(reqParams params.Params) (interface{}, *neorpc.Error) {
-	b, respErr := s.getHistoricParams(reqParams)
+	nextH, respErr := s.getHistoricParams(reqParams)
 	if respErr != nil {
 		return nil, respErr
 	}
@@ -1843,7 +1842,7 @@ func (s *Server) invokeFunctionHistoric(reqParams params.Params) (interface{}, *
 	if respErr != nil {
 		return nil, respErr
 	}
-	return s.runScriptInVM(trigger.Application, tx.Script, util.Uint160{}, tx, b, verbose)
+	return s.runScriptInVM(trigger.Application, tx.Script, util.Uint160{}, tx, &nextH, verbose)
 }
 
 func (s *Server) getInvokeFunctionParams(reqParams params.Params) (*transaction.Transaction, bool, *neorpc.Error) {
@@ -1899,7 +1898,7 @@ func (s *Server) invokescript(reqParams params.Params) (interface{}, *neorpc.Err
 
 // invokescripthistoric implements the `invokescripthistoric` RPC call.
 func (s *Server) invokescripthistoric(reqParams params.Params) (interface{}, *neorpc.Error) {
-	b, respErr := s.getHistoricParams(reqParams)
+	nextH, respErr := s.getHistoricParams(reqParams)
 	if respErr != nil {
 		return nil, respErr
 	}
@@ -1910,7 +1909,7 @@ func (s *Server) invokescripthistoric(reqParams params.Params) (interface{}, *ne
 	if respErr != nil {
 		return nil, respErr
 	}
-	return s.runScriptInVM(trigger.Application, tx.Script, util.Uint160{}, tx, b, verbose)
+	return s.runScriptInVM(trigger.Application, tx.Script, util.Uint160{}, tx, &nextH, verbose)
 }
 
 func (s *Server) getInvokeScriptParams(reqParams params.Params) (*transaction.Transaction, bool, *neorpc.Error) {
@@ -1953,7 +1952,7 @@ func (s *Server) invokeContractVerify(reqParams params.Params) (interface{}, *ne
 
 // invokeContractVerifyHistoric implements the `invokecontractverifyhistoric` RPC call.
 func (s *Server) invokeContractVerifyHistoric(reqParams params.Params) (interface{}, *neorpc.Error) {
-	b, respErr := s.getHistoricParams(reqParams)
+	nextH, respErr := s.getHistoricParams(reqParams)
 	if respErr != nil {
 		return nil, respErr
 	}
@@ -1964,7 +1963,7 @@ func (s *Server) invokeContractVerifyHistoric(reqParams params.Params) (interfac
 	if respErr != nil {
 		return nil, respErr
 	}
-	return s.runScriptInVM(trigger.Verification, invocationScript, scriptHash, tx, b, false)
+	return s.runScriptInVM(trigger.Verification, invocationScript, scriptHash, tx, &nextH, false)
 }
 
 func (s *Server) getInvokeContractVerifyParams(reqParams params.Params) (util.Uint160, *transaction.Transaction, []byte, *neorpc.Error) {
@@ -2003,68 +2002,52 @@ func (s *Server) getInvokeContractVerifyParams(reqParams params.Params) (util.Ui
 	return scriptHash, tx, invocationScript, nil
 }
 
-// getHistoricParams checks that historic calls are supported and returns fake block
+// getHistoricParams checks that historic calls are supported and returns index of
-// with the specified index to perform the historic call. It also checks that
+// a fake next block to perform the historic call. It also checks that
 // specified stateroot is stored at the specified height for further request
 // handling consistency.
-func (s *Server) getHistoricParams(reqParams params.Params) (*block.Block, *neorpc.Error) {
+func (s *Server) getHistoricParams(reqParams params.Params) (uint32, *neorpc.Error) {
 	if s.chain.GetConfig().KeepOnlyLatestState {
-		return nil, neorpc.NewInvalidRequestError(fmt.Sprintf("only latest state is supported: %s", errKeepOnlyLatestState))
+		return 0, neorpc.NewInvalidRequestError(fmt.Sprintf("only latest state is supported: %s", errKeepOnlyLatestState))
 	}
 	if len(reqParams) < 1 {
-		return nil, neorpc.ErrInvalidParams
+		return 0, neorpc.ErrInvalidParams
 	}
 	height, respErr := s.blockHeightFromParam(reqParams.Value(0))
 	if respErr != nil {
 		hash, err := reqParams.Value(0).GetUint256()
 		if err != nil {
-			return nil, neorpc.NewInvalidParamsError(fmt.Sprintf("invalid block hash or index or stateroot hash: %s", err))
+			return 0, neorpc.NewInvalidParamsError(fmt.Sprintf("invalid block hash or index or stateroot hash: %s", err))
 		}
 		b, err := s.chain.GetBlock(hash)
 		if err != nil {
 			stateH, err := s.chain.GetStateModule().GetLatestStateHeight(hash)
 			if err != nil {
-				return nil, neorpc.NewInvalidParamsError(fmt.Sprintf("unknown block or stateroot: %s", err))
+				return 0, neorpc.NewInvalidParamsError(fmt.Sprintf("unknown block or stateroot: %s", err))
 			}
 			height = int(stateH)
 		} else {
 			height = int(b.Index)
 		}
 	}
-	b, err := s.getFakeNextBlock(uint32(height + 1))
+	if height > math.MaxUint32 {
-	if err != nil {
+		return 0, neorpc.NewInvalidParamsError("historic height exceeds max uint32 value")
-		return nil, neorpc.NewInternalServerError(fmt.Sprintf("can't create fake block for height %d: %s", height+1, err))
 	}
-	return b, nil
+	return uint32(height) + 1, nil
 }
 
-func (s *Server) getFakeNextBlock(nextBlockHeight uint32) (*block.Block, error) {
+func (s *Server) prepareInvocationContext(t trigger.Type, script []byte, contractScriptHash util.Uint160, tx *transaction.Transaction, nextH *uint32, verbose bool) (*interop.Context, *neorpc.Error) {
-	// When transferring funds, script execution does no auto GAS claim,
-	// because it depends on persisting tx height.
-	// This is why we provide block here.
-	b := block.New(s.stateRootEnabled)
-	b.Index = nextBlockHeight
-	hdr, err := s.chain.GetHeader(s.chain.GetHeaderHash(int(nextBlockHeight - 1)))
-	if err != nil {
-		return nil, err
-	}
-	b.Timestamp = hdr.Timestamp + uint64(s.chain.GetConfig().SecondsPerBlock*int(time.Second/time.Millisecond))
-	return b, nil
-}
-
-func (s *Server) prepareInvocationContext(t trigger.Type, script []byte, contractScriptHash util.Uint160, tx *transaction.Transaction, b *block.Block, verbose bool) (*interop.Context, *neorpc.Error) {
 	var (
 		err error
 		ic  *interop.Context
 	)
-	if b == nil {
+	if nextH == nil {
-		b, err = s.getFakeNextBlock(s.chain.BlockHeight() + 1)
+		ic, err = s.chain.GetTestVM(t, tx, nil)
 		if err != nil {
-			return nil, neorpc.NewInternalServerError(fmt.Sprintf("can't create fake block: %s", err))
+			return nil, neorpc.NewInternalServerError(fmt.Sprintf("failed to create test VM: %s", err))
 		}
-		ic = s.chain.GetTestVM(t, tx, b)
 	} else {
-		ic, err = s.chain.GetTestHistoricVM(t, tx, b)
+		ic, err = s.chain.GetTestHistoricVM(t, tx, *nextH)
 		if err != nil {
 			return nil, neorpc.NewInternalServerError(fmt.Sprintf("failed to create historic VM: %s", err))
 		}
@@ -2096,8 +2079,8 @@ func (s *Server) prepareInvocationContext(t trigger.Type, script []byte, contrac
 // witness invocation script in case of `verification` trigger (it pushes `verify`
 // arguments on stack before verification). In case of contract verification
 // contractScriptHash should be specified.
-func (s *Server) runScriptInVM(t trigger.Type, script []byte, contractScriptHash util.Uint160, tx *transaction.Transaction, b *block.Block, verbose bool) (*result.Invoke, *neorpc.Error) {
+func (s *Server) runScriptInVM(t trigger.Type, script []byte, contractScriptHash util.Uint160, tx *transaction.Transaction, nextH *uint32, verbose bool) (*result.Invoke, *neorpc.Error) {
-	ic, respErr := s.prepareInvocationContext(t, script, contractScriptHash, tx, b, verbose)
+	ic, respErr := s.prepareInvocationContext(t, script, contractScriptHash, tx, nextH, verbose)
 	if respErr != nil {
 		return nil, respErr
 	}
@@ -2111,16 +2094,12 @@ func (s *Server) runScriptInVM(t trigger.Type, script []byte, contractScriptHash
 	var id uuid.UUID
 
 	if sess != nil {
-		// b == nil only when we're not using MPT-backed storage, therefore
+		// nextH == nil only when we're not using MPT-backed storage, therefore
 		// the second attempt won't stop here.
-		if s.config.SessionBackedByMPT && b == nil {
+		if s.config.SessionBackedByMPT && nextH == nil {
 			ic.Finalize()
-			b, err = s.getFakeNextBlock(ic.Block.Index)
-			if err != nil {
-				return nil, neorpc.NewInternalServerError(fmt.Sprintf("unable to prepare block for historic call: %s", err))
-			}
 			// Rerun with MPT-backed storage.
-			return s.runScriptInVM(t, script, contractScriptHash, tx, b, verbose)
+			return s.runScriptInVM(t, script, contractScriptHash, tx, &ic.Block.Index, verbose)
 		}
 		id = uuid.New()
 		sessionID := id.String()

pkg/smartcontract/contract.go

@@ -14,7 +14,7 @@ import (
 // where n is the length of publicKeys.
 func CreateMultiSigRedeemScript(m int, publicKeys keys.PublicKeys) ([]byte, error) {
 	if m < 1 {
-		return nil, fmt.Errorf("param m cannot be smaller or equal to 1 got %d", m)
+		return nil, fmt.Errorf("param m cannot be smaller than 1, got %d", m)
 	}
 	if m > len(publicKeys) {
 		return nil, fmt.Errorf("length of the signatures (%d) is higher then the number of public keys", m)

pkg/vm/interop.go

@@ -1,66 +0,0 @@
-package vm
-
-import (
-	"errors"
-	"fmt"
-	"sort"
-
-	"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
-	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
-)
-
-// interopIDFuncPrice adds an ID to the InteropFuncPrice.
-type interopIDFuncPrice struct {
-	ID            uint32
-	Func          func(vm *VM) error
-	Price         int64
-	RequiredFlags callflag.CallFlag
-}
-
-var defaultVMInterops = []interopIDFuncPrice{
-	{ID: interopnames.ToID([]byte(interopnames.SystemRuntimeLog)),
-		Func: runtimeLog, Price: 1 << 15, RequiredFlags: callflag.AllowNotify},
-	{ID: interopnames.ToID([]byte(interopnames.SystemRuntimeNotify)),
-		Func: runtimeNotify, Price: 1 << 15, RequiredFlags: callflag.AllowNotify},
-}
-
-func init() {
-	sort.Slice(defaultVMInterops, func(i, j int) bool { return defaultVMInterops[i].ID < defaultVMInterops[j].ID })
-}
-
-func defaultSyscallHandler(v *VM, id uint32) error {
-	n := sort.Search(len(defaultVMInterops), func(i int) bool {
-		return defaultVMInterops[i].ID >= id
-	})
-	if n >= len(defaultVMInterops) || defaultVMInterops[n].ID != id {
-		return errors.New("syscall not found")
-	}
-	d := defaultVMInterops[n]
-	ctxFlag := v.Context().sc.callFlag
-	if !ctxFlag.Has(d.RequiredFlags) {
-		return fmt.Errorf("missing call flags: %05b vs %05b", ctxFlag, d.RequiredFlags)
-	}
-	return d.Func(v)
-}
-
-// runtimeLog handles the syscall "System.Runtime.Log" for printing and logging stuff.
-func runtimeLog(vm *VM) error {
-	msg := vm.Estack().Pop().String()
-	fmt.Printf("NEO-GO-VM (log) > %s\n", msg)
-	return nil
-}
-
-// runtimeNotify handles the syscall "System.Runtime.Notify" for printing and logging stuff.
-func runtimeNotify(vm *VM) error {
-	name := vm.Estack().Pop().String()
-	item := vm.Estack().Pop()
-	fmt.Printf("NEO-GO-VM (notify) > [%s] %s\n", name, item.Value())
-	return nil
-}
-
-// init sorts the global defaultVMInterops value.
-func init() {
-	sort.Slice(defaultVMInterops, func(i, j int) bool {
-		return defaultVMInterops[i].ID < defaultVMInterops[j].ID
-	})
-}

pkg/vm/vm.go

@@ -108,8 +108,6 @@ func NewWithTrigger(t trigger.Type) *VM {
 	vm := &VM{
 		state:   vmstate.None,
 		trigger: t,
-
-		SyscallHandler: defaultSyscallHandler,
 	}
 
 	initStack(&vm.istack, "invocation", nil)
@@ -1458,6 +1456,9 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
 
 	case opcode.SYSCALL:
 		interopID := GetInteropID(parameter)
+		if v.SyscallHandler == nil {
+			panic("vm's SyscallHandler is not initialized")
+		}
 		err := v.SyscallHandler(v, interopID)
 		if err != nil {
 			panic(fmt.Sprintf("failed to invoke syscall %d: %s", interopID, err))

pkg/vm/vm_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
@@ -2747,6 +2748,19 @@ func TestRemoveReferrer(t *testing.T) {
 	assert.Equal(t, 0, int(vm.refs))
 }
 
+func TestUninitializedSyscallHandler(t *testing.T) {
+	v := newTestVM()
+	v.Reset(trigger.Application) // Reset SyscallHandler.
+	id := make([]byte, 4)
+	binary.LittleEndian.PutUint32(id, interopnames.ToID([]byte(interopnames.SystemRuntimeGasLeft)))
+	script := append([]byte{byte(opcode.SYSCALL)}, id...)
+	v.LoadScript(script)
+	err := v.Run()
+	require.Error(t, err)
+	require.True(t, strings.Contains(err.Error(), "SyscallHandler is not initialized"), err.Error())
+	assert.Equal(t, true, v.HasFailed())
+}
+
 func makeProgram(opcodes ...opcode.Opcode) []byte {
 	prog := make([]byte, len(opcodes)+1) // RET
 	for i := 0; i < len(opcodes); i++ {