diff --git a/eth/tracers/tracer.go b/eth/tracers/tracer.go
index ba6592537300a62b81910f4e18938e842c7ffd51..218903dd92a0d0423145e7366ba4765eb4ff0cd7 100644
--- a/eth/tracers/tracer.go
+++ b/eth/tracers/tracer.go
@@ -505,7 +505,7 @@ func (jst *Tracer) Stop(err error) {
// call executes a method on a JS object, catching any errors, formatting and
// returning them as error objects.
-func (jst *Tracer) call(method string, args ...string) (json.RawMessage, error) {
+func (jst *Tracer) call(noret bool, method string, args ...string) (json.RawMessage, error) {
// Execute the JavaScript call and return any error
jst.vm.PushString(method)
for _, arg := range args {
@@ -519,7 +519,21 @@ func (jst *Tracer) call(method string, args ...string) (json.RawMessage, error)
return nil, errors.New(err)
}
// No error occurred, extract return value and return
- return json.RawMessage(jst.vm.JsonEncode(-1)), nil
+ if noret {
+ return nil, nil
+ }
+ // Push a JSON marshaller onto the stack. We can't marshal from the out-
+ // side because duktape can crash on large nestings and we can't catch
+ // C++ exceptions ourselves from Go. TODO(karalabe): Yuck, why wrap?!
+ jst.vm.PushString("(JSON.stringify)")
+ jst.vm.Eval()
+
+ jst.vm.Swap(-1, -2)
+ if code = jst.vm.Pcall(1); code != 0 {
+ err := jst.vm.SafeToString(-1)
+ return nil, errors.New(err)
+ }
+ return json.RawMessage(jst.vm.SafeToString(-1)), nil
}
func wrapError(context string, err error) error {
@@ -578,7 +592,7 @@ func (jst *Tracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost
*jst.errorValue = err.Error()
}
- if _, err := jst.call("step", "log", "db"); err != nil {
+ if _, err := jst.call(true, "step", "log", "db"); err != nil {
jst.err = wrapError("step", err)
}
}
@@ -592,7 +606,7 @@ func (jst *Tracer) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost
jst.errorValue = new(string)
*jst.errorValue = err.Error()
- if _, err := jst.call("fault", "log", "db"); err != nil {
+ if _, err := jst.call(true, "fault", "log", "db"); err != nil {
jst.err = wrapError("fault", err)
}
}
@@ -640,7 +654,7 @@ func (jst *Tracer) GetResult() (json.RawMessage, error) {
jst.vm.PutPropString(jst.stateObject, "ctx")
// Finalize the trace and return the results
- result, err := jst.call("result", "ctx", "db")
+ result, err := jst.call(false, "result", "ctx", "db")
if err != nil {
jst.err = wrapError("result", err)
}
diff --git a/eth/tracers/tracer_test.go b/eth/tracers/tracer_test.go
index 7cda2e533064b16d60785cc5203022af3321c132..033824474d26f2e3018ab1b610c90630966794b1 100644
--- a/eth/tracers/tracer_test.go
+++ b/eth/tracers/tracer_test.go
@@ -78,7 +78,7 @@ func runTrace(tracer *Tracer, vmctx *vmContext) (json.RawMessage, error) {
}
func TestTracer(t *testing.T) {
- execTracer := func(code string) []byte {
+ execTracer := func(code string) ([]byte, string) {
t.Helper()
ctx := &vmContext{blockCtx: vm.BlockContext{BlockNumber: big.NewInt(1)}, txCtx: vm.TxContext{GasPrice: big.NewInt(100000)}}
tracer, err := New(code, ctx.txCtx)
@@ -87,13 +87,14 @@ func TestTracer(t *testing.T) {
}
ret, err := runTrace(tracer, ctx)
if err != nil {
- t.Fatal(err)
+ return nil, err.Error() // Stringify to allow comparison without nil checks
}
- return ret
+ return ret, ""
}
for i, tt := range []struct {
code string
want string
+ fail string
}{
{ // tests that we don't panic on bad arguments to memory access
code: "{depths: [], step: function(log) { this.depths.push(log.memory.slice(-1,-2)); }, fault: function() {}, result: function() { return this.depths; }}",
@@ -116,10 +117,13 @@ func TestTracer(t *testing.T) {
}, { // tests intrinsic gas
code: "{depths: [], step: function() {}, fault: function() {}, result: function(ctx) { return ctx.gasPrice+'.'+ctx.gasUsed+'.'+ctx.intrinsicGas; }}",
want: `"100000.6.21000"`,
+ }, { // tests too deep object / serialization crash
+ code: "{step: function() {}, fault: function() {}, result: function() { var o={}; var x=o; for (var i=0; i<1000; i++){ o.foo={}; o=o.foo; } return x; }}",
+ fail: "RangeError: json encode recursion limit in server-side tracer function 'result'",
},
} {
- if have := execTracer(tt.code); tt.want != string(have) {
- t.Errorf("testcase %d: expected return value to be %s got %s\n\tcode: %v", i, tt.want, string(have), tt.code)
+ if have, err := execTracer(tt.code); tt.want != string(have) || tt.fail != err {
+ t.Errorf("testcase %d: expected return value to be '%s' got '%s', error to be '%s' got '%s'\n\tcode: %v", i, tt.want, string(have), tt.fail, err, tt.code)
}
}
}