e := fmt.Errorf(format, a...)
	ee := Error{}
	ee.msg = e.Error()
	ee.cause = errors.Unwrap(e)
	return ee
}

// Unwrap the internal error.
func (e Error) Unwrap() error { return e.cause }

// Error 'error' compatible method.
func (e Error) Error() string {
	if e.msg == "" {
		return "crypto: cause <nil>"
	}
	return e.msg
}

var (
	// ErrInvalidEncryptionMethod indicates that the specified SSE encryption method

	}
	return toAPIError(ctx, fmt.Errorf("error exporting %s from %s with: %w", entity, fname, err))
}

// wraps import error for more context
func importError(ctx context.Context, err error, fname, entity string) APIError {
	if entity == "" {
		return toAPIError(ctx, fmt.Errorf("error importing %s with: %w", fname, err))
	}

			s3Error = checkRequestAuthType(ctx, r, policy.GetObjectAction, bucket, object)
		}
	}

	if s3Error != ErrNone {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL)
		return
	}

	objInfo, err := objectAPI.GetObjectInfo(ctx, bucket, object, opts)
	if err != nil {
		s3Error = checkRequestAuthType(ctx, r, policy.ListBucketAction, bucket, object)
		if s3Error == ErrNone {

		return
	}

	vars := mux.Vars(r)
	bucket := vars["bucket"]

	if s3Error := checkRequestAuthType(ctx, r, policy.PutBucketPolicyAction, bucket, ""); s3Error != ErrNone {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL)
		return
	}

	// Check if bucket exists.
	if _, err := objAPI.GetBucketInfo(ctx, bucket, BucketOptions{}); err != nil {

		}
	case authTypeSignedV2, authTypePresignedV2:
		if s3Error = isReqAuthenticatedV2(r); s3Error != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL)
			return
		}
	case authTypePresigned, authTypeSigned:
		if s3Error = reqSignatureV4Verify(r, globalSite.Region, serviceS3); s3Error != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL)
			return
		}

}

// Verify if request has valid AWS Signature Version '2'.
func isReqAuthenticatedV2(r *http.Request) (s3Error APIErrorCode) {
	if isRequestSignatureV2(r) {
		return doesSignV2Match(r)
	}
	return doesPresignV2SignatureMatch(r)
}

func reqSignatureV4Verify(r *http.Request, region string, stype serviceType) (s3Error APIErrorCode) {
	sha256sum := getContentSha256Cksum(r, stype)
	switch {
	case isRequestSignatureV4(r):

				HTTPStatusCode: http.StatusBadRequest,
			}
		case replication.Error:
			apiErr = APIError{
				Code:           "MalformedXML",
				Description:    e.Error(),
				HTTPStatusCode: http.StatusBadRequest,
			}
		case tags.Error:
			apiErr = APIError{
				Code:           e.Code(),
				Description:    e.Error(),
				HTTPStatusCode: http.StatusBadRequest,
			}
		case policy.Error:

	bucketName := vars["bucket"]

	if bucketName == "" {
		if s3Error := checkRequestAuthType(ctx, r, policy.ListenNotificationAction, bucketName, ""); s3Error != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL)
			return
		}
	} else {
		if s3Error := checkRequestAuthType(ctx, r, policy.ListenBucketNotificationAction, bucketName, ""); s3Error != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL)

type ObjectNamePrefixAsSlash GenericError

// Error returns string an error formatted as the given text.
func (e ObjectNameInvalid) Error() string {
	return "Object name invalid: " + e.Bucket + "/" + e.Object
}

// Error returns string an error formatted as the given text.
func (e ObjectNameTooLong) Error() string {
	return "Object name too long: " + e.Bucket + "/" + e.Object
}

	// The real disk
	disk StorageAPI
	// Programmed errors: API call number => error to return
	errors map[int]error
	// The error to return when no error value is programmed
	defaultErr error
	// The current API call number
	callNR int
	// Data protection
	mu sync.Mutex
}

func newNaughtyDisk(d StorageAPI, errs map[int]error, defaultErr error) *naughtyDisk {
	return &naughtyDisk{disk: d, errors: errs, defaultErr: defaultErr}
}