Function rwLockKeySet

command/crypto/jwk/keyset.go:228–309

(filename string)

}

func rwLockKeySet(filename string) (jwks *jose.JSONWebKeySet, writeFunc func(bool) error, err error) {
	var f *os.File

	f, err = os.OpenFile(filename, os.O_RDWR|os.O_CREATE, 0600)
	if err != nil {
		err = errs.FileError(err, filename)
		return
	}

	fd := int(f.Fd()) // #nosec G115 -- uintptr comes from file descriptor

	// non-blocking exclusive lock
	err = sysutils.FileLock(fd)
	switch {
	case err == nil: // continue
	case errors.Is(err, syscall.EWOULDBLOCK):
		f.Close()
		err = errors.Errorf("error reading %s: file is locked", filename)
		return
	default:
		f.Close()
		err = errors.Wrapf(err, "error locking %s", filename)
		return
	}

	// close and unlock file on errors
	defer func() {
		if err != nil {
			sysutils.FileUnlock(fd)
			f.Close()
		}
	}()

	// Read key set
	var b []byte
	b, err = io.ReadAll(f)
	if err != nil {
		err = errors.Wrapf(err, "error reading %s", filename)
		return
	}

	// Unmarshal the plain JWKSet
	jwks = new(jose.JSONWebKeySet)
	if len(b) > 0 {
		if err = json.Unmarshal(b, jwks); err != nil {
			err = errors.Wrapf(err, "error reading %s", filename)
			return
		}
	}

	writeFunc = func(write bool) (err error) {
		if write {
			if b, err1 := json.MarshalIndent(jwks, "", "  "); err1 != nil {
				err = errors.Wrapf(err1, "error marshaling %s", filename)
			} else {
				if err1 := f.Truncate(0); err1 != nil {
					err = errors.Wrapf(err1, "error writing %s", filename)
				} else {