pkg/config: use DisallowUnknownFields

DisallowUnknownFields was added in Go 1.10,
remove our custom machinery for checking unknown fields.

1 files changed, 4 insertions, 84 deletions

diff --git a/pkg/config/config.go b/pkg/config/config.go
index 49d030499..a4f56c225 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -4,11 +4,10 @@
 package config
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
-	"reflect"
-	"strings"
 
 	"github.com/google/syzkaller/pkg/osutil"
 )
@@ -25,10 +24,9 @@ func LoadFile(filename string, cfg interface{}) error {
 }
 
 func LoadData(data []byte, cfg interface{}) error {
-	if err := checkUnknownFields(data, reflect.ValueOf(cfg).Type()); err != nil {
-		return err
-	}
-	if err := json.Unmarshal(data, cfg); err != nil {
+	dec := json.NewDecoder(bytes.NewReader(data))
+	dec.DisallowUnknownFields()
+	if err := dec.Decode(cfg); err != nil {
 		return fmt.Errorf("failed to parse config file: %v", err)
 	}
 	return nil
@@ -45,81 +43,3 @@ func SaveFile(filename string, cfg interface{}) error {
 func SaveData(cfg interface{}) ([]byte, error) {
 	return json.MarshalIndent(cfg, "", "\t")
 }
-
-func checkUnknownFields(data []byte, typ reflect.Type) error {
-	if typ.Kind() != reflect.Ptr || typ.Elem().Kind() != reflect.Struct {
-		return fmt.Errorf("config type is not pointer to struct")
-	}
-	return checkUnknownFieldsRec(data, "", typ)
-}
-
-func checkUnknownFieldsRec(data []byte, prefix string, typ reflect.Type) error {
-	if typ.Kind() == reflect.Ptr {
-		typ = typ.Elem()
-	}
-	if typ.Kind() != reflect.Struct {
-		return fmt.Errorf("config type is not pointer to struct")
-	}
-	fields := make(map[string]reflect.Type)
-	for i := 0; i < typ.NumField(); i++ {
-		field := typ.Field(i)
-		tag := field.Tag.Get("json")
-		tag = strings.TrimSuffix(tag, ",omitempty")
-		if tag == "-" {
-			continue
-		}
-		name := strings.ToLower(field.Name)
-		if tag != "" {
-			if tag != strings.ToLower(tag) {
-				return fmt.Errorf("json tag on '%v%v' should be lower-case", prefix, name)
-			}
-			name = tag
-		}
-		fields[name] = field.Type
-	}
-	f := make(map[string]interface{})
-	if err := json.Unmarshal(data, &f); err != nil {
-		return fmt.Errorf("failed to parse config file: %v", err)
-	}
-	for k, v := range f {
-		field, ok := fields[strings.ToLower(k)]
-		if !ok {
-			return fmt.Errorf("unknown field '%v%v' in config", prefix, k)
-		}
-		if v != nil && field.Kind() == reflect.Slice &&
-			(field.PkgPath() != "encoding/json" || field.Name() != "RawMessage") {
-			vv := reflect.ValueOf(v)
-			if vv.Type().Kind() != reflect.Slice {
-				return fmt.Errorf("bad json array type '%v%v'", prefix, k)
-			}
-			for i := 0; i < vv.Len(); i++ {
-				e := vv.Index(i).Interface()
-				prefix1 := fmt.Sprintf("%v%v[%v].", prefix, k, i)
-				if err := checkUnknownFieldsStruct(e, prefix1, field.Elem()); err != nil {
-					return err
-				}
-			}
-		}
-		if err := checkUnknownFieldsStruct(v, prefix+k+".", field); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func checkUnknownFieldsStruct(val interface{}, prefix string, typ reflect.Type) error {
-	if typ.Kind() == reflect.Ptr {
-		typ = typ.Elem()
-	}
-	if typ.Kind() != reflect.Struct {
-		return nil
-	}
-	if typ.PkgPath() == "time" && typ.Name() == "Time" {
-		return nil
-	}
-	inner, err := json.Marshal(val)
-	if err != nil {
-		return fmt.Errorf("failed to marshal inner struct %q: %v", prefix, err)
-	}
-	return checkUnknownFieldsRec(inner, prefix, typ)
-}