interop: add System.Runtime.GetNetwork, fix #2038

Signed-off-by: Evgeniy Stratonikov <evgeniy@nspcc.ru>

pkg/compiler/syscall_test.go

@@ -74,6 +74,7 @@ func TestSyscallExecution(t *testing.T) {
 		"runtime.GetEntryScriptHash":       {interopnames.SystemRuntimeGetEntryScriptHash, nil, false},
 		"runtime.GetExecutingScriptHash":   {interopnames.SystemRuntimeGetExecutingScriptHash, nil, false},
 		"runtime.GetInvocationCounter":     {interopnames.SystemRuntimeGetInvocationCounter, nil, false},
+		"runtime.GetNetwork":               {interopnames.SystemRuntimeGetNetwork, nil, false},
 		"runtime.GetNotifications":         {interopnames.SystemRuntimeGetNotifications, []string{u160}, false},
 		"runtime.GetScriptContainer":       {interopnames.SystemRuntimeGetScriptContainer, nil, false},
 		"runtime.GetTime":                  {interopnames.SystemRuntimeGetTime, nil, false},

pkg/core/interop/interopnames/names.go

@@ -24,6 +24,7 @@ const (
 	SystemRuntimeGetEntryScriptHash     = "System.Runtime.GetEntryScriptHash"
 	SystemRuntimeGetExecutingScriptHash = "System.Runtime.GetExecutingScriptHash"
 	SystemRuntimeGetInvocationCounter   = "System.Runtime.GetInvocationCounter"
+	SystemRuntimeGetNetwork             = "System.Runtime.GetNetwork"
 	SystemRuntimeGetNotifications       = "System.Runtime.GetNotifications"
 	SystemRuntimeGetScriptContainer     = "System.Runtime.GetScriptContainer"
 	SystemRuntimeGetTime                = "System.Runtime.GetTime"
@@ -61,6 +62,7 @@ var names = []string{
 	SystemRuntimeGetEntryScriptHash,
 	SystemRuntimeGetExecutingScriptHash,
 	SystemRuntimeGetInvocationCounter,
+	SystemRuntimeGetNetwork,
 	SystemRuntimeGetNotifications,
 	SystemRuntimeGetScriptContainer,
 	SystemRuntimeGetTime,

pkg/core/interop/runtime/util.go

@@ -67,3 +67,10 @@ func GetInvocationCounter(ic *interop.Context) error {
 	ic.VM.Estack().PushVal(count)
 	return nil
 }
+
+// GetNetwork returns chain network number.
+func GetNetwork(ic *interop.Context) error {
+	m := ic.Chain.GetConfig().Magic
+	ic.VM.Estack().PushVal(uint32(m))
+	return nil
+}

pkg/core/interop_system_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 
 	"github.com/nspcc-dev/neo-go/internal/random"
+	"github.com/nspcc-dev/neo-go/internal/testchain"
 	"github.com/nspcc-dev/neo-go/pkg/core/dao"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
@@ -1202,6 +1203,25 @@ func TestLoadToken(t *testing.T) {
 	})
 }
 
+func TestRuntimeGetNetwork(t *testing.T) {
+	bc := newTestChain(t)
+
+	w := io.NewBufBinWriter()
+	emit.Syscall(w.BinWriter, interopnames.SystemRuntimeGetNetwork)
+	require.NoError(t, w.Err)
+
+	tx := transaction.New(w.Bytes(), 10_000)
+	tx.ValidUntilBlock = bc.BlockHeight() + 1
+	addSigners(neoOwner, tx)
+	require.NoError(t, testchain.SignTx(bc, tx))
+
+	require.NoError(t, bc.AddBlock(bc.newBlock(tx)))
+
+	aer, err := bc.GetAppExecResults(tx.Hash(), trigger.Application)
+	require.NoError(t, err)
+	checkResult(t, &aer[0], stackitem.Make(uint32(bc.config.Magic)))
+}
+
 func TestRuntimeBurnGas(t *testing.T) {
 	bc := newTestChain(t)
 

pkg/core/interops.go

@@ -50,6 +50,7 @@ var systemInterops = []interop.Function{
 	{Name: interopnames.SystemRuntimeGetEntryScriptHash, Func: runtime.GetEntryScriptHash, Price: 1 << 4},
 	{Name: interopnames.SystemRuntimeGetExecutingScriptHash, Func: runtime.GetExecutingScriptHash, Price: 1 << 4},
 	{Name: interopnames.SystemRuntimeGetInvocationCounter, Func: runtime.GetInvocationCounter, Price: 1 << 4},
+	{Name: interopnames.SystemRuntimeGetNetwork, Func: runtime.GetNetwork, Price: 1 << 3},
 	{Name: interopnames.SystemRuntimeGetNotifications, Func: runtime.GetNotifications, Price: 1 << 8, ParamCount: 1},
 	{Name: interopnames.SystemRuntimeGetScriptContainer, Func: engineGetScriptContainer, Price: 1 << 3},
 	{Name: interopnames.SystemRuntimeGetTime, Func: runtime.GetTime, Price: 1 << 3, RequiredFlags: callflag.ReadStates},

pkg/interop/runtime/runtime.go

@@ -46,6 +46,12 @@ func Notify(name string, args ...interface{}) {
 	neogointernal.Syscall2NoReturn("System.Runtime.Notify", name, args)
 }
 
+// GetNetwork returns network magic number. This function uses
+// `System.Runtime.GetNetwork` syscall.
+func GetNetwork() int {
+	return neogointernal.Syscall0("System.Runtime.GetNetwork").(int)
+}
+
 // GetTime returns the timestamp of the most recent block. Note that when running
 // script in test mode this would be the last accepted (persisted) block in the
 // chain, but when running as a part of the new block the time returned is the