// Copyright (c) 2015-2021 MinIO, Inc.//// This file is part of MinIO Object Storage stack//// This program is free software: you can redistribute it and/or modify// it under the terms of the GNU Affero General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// This program is distributed in the hope that it will be useful// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU Affero General Public License for more details.//// You should have received a copy of the GNU Affero General Public License// along with this program.  If not, see <http://www.gnu.org/licenses/>. package cmd import (	"bytes"	"context"	"errors"	"io/ioutil"	"net/http" 	"github.com/minio/minio/internal/hash") var errConfigNotFound = errors.New("config file not found") func readConfigWithMetadata(ctx context.Context, store objectIO, configFile string) ([]byte, ObjectInfo, error) {	r, err := store.GetObjectNInfo(ctx, minioMetaBucket, configFile, nil, http.Header{}, readLock, ObjectOptions{})	if err != nil {		// Treat object not found as config not found.		if isErrObjectNotFound(err) {			return nil, ObjectInfo{}, errConfigNotFound		} 		return nil, ObjectInfo{}, err	}	defer r.Close() 	buf, err := ioutil.ReadAll(r)	if err != nil {		return nil, ObjectInfo{}, err	}	if len(buf) == 0 {		return nil, ObjectInfo{}, errConfigNotFound	}	return buf, r.ObjInfo, nil} func readConfig(ctx context.Context, store objectIO, configFile string) ([]byte, error) {	buf, _, err := readConfigWithMetadata(ctx, store, configFile)	return buf, err} type objectDeleter interface {	DeleteObject(ctx context.Context, bucket, object string, opts ObjectOptions) (ObjectInfo, error)} func deleteConfig(ctx context.Context, objAPI objectDeleter, configFile string) error {	_, err := objAPI.DeleteObject(ctx, minioMetaBucket, configFile, ObjectOptions{		DeletePrefix: true,	})	if err != nil && isErrObjectNotFound(err) {		return errConfigNotFound	}	return err} func saveConfig(ctx context.Context, store objectIO, configFile string, data []byte) error {	hashReader, err := hash.NewReader(bytes.NewReader(data), int64(len(data)), "", getSHA256Hash(data), int64(len(data)))	if err != nil {		return err	} 	_, err = store.PutObject(ctx, minioMetaBucket, configFile, NewPutObjReader(hashReader), ObjectOptions{MaxParity: true})	return err} func checkConfig(ctx context.Context, objAPI ObjectLayer, configFile string) error {	if _, err := objAPI.GetObjectInfo(ctx, minioMetaBucket, configFile, ObjectOptions{}); err != nil {		// Treat object not found as config not found.		if isErrObjectNotFound(err) {			return errConfigNotFound		} 		return err	}	return nil}