containerd-shim: Use abstract namespace for the unix socket

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>

linux/bundle.go

@@ -44,12 +44,14 @@ func newBundle(path, namespace, id string, spec []byte) (b *bundle, err error) {
 	defer f.Close()
 	_, err = io.Copy(f, bytes.NewReader(spec))
 	return &bundle{
+		id:        id,
 		path:      path,
 		namespace: namespace,
 	}, err
 }
 
 type bundle struct {
+	id        string
 	path      string
 	namespace string
 }
@@ -61,7 +63,7 @@ func (b *bundle) NewShim(ctx context.Context, binary string, remote bool) (*clie
 		opt = client.WithLocal
 	}
 	return client.New(ctx, client.Config{
-		Address:   filepath.Join(b.path, "shim.sock"),
+		Address:   b.shimAddress(),
 		Path:      b.path,
 		Namespace: b.namespace,
 	}, opt)
@@ -74,7 +76,7 @@ func (b *bundle) Connect(ctx context.Context, remote bool) (*client.Client, erro
 		opt = client.WithLocal
 	}
 	return client.New(ctx, client.Config{
-		Address:   filepath.Join(b.path, "shim.sock"),
+		Address:   b.shimAddress(),
 		Path:      b.path,
 		Namespace: b.namespace,
 	}, opt)
@@ -89,3 +91,8 @@ func (b *bundle) Spec() ([]byte, error) {
 func (b *bundle) Delete() error {
 	return os.RemoveAll(b.path)
 }
+
+func (b *bundle) shimAddress() string {
+	return filepath.Join(string(filepath.Separator), "containerd-shim", b.namespace, b.id, "shim.sock")
+
+}

linux/shim/client.go

@@ -34,11 +34,14 @@ func WithStart(binary string) ClientOpt {
 		if err != nil {
 			return nil, nil, err
 		}
-		// close our side of the socket, do not close the listener as it will
-		// remove the socket from disk
 		defer socket.Close()
+		f, err := socket.File()
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "failed to get fd for socket %s", config.Address)
+		}
+		defer f.Close()
 
-		cmd := newCommand(binary, config, socket)
+		cmd := newCommand(binary, config, f)
 		if err := reaper.Default.Start(cmd); err != nil {
 			return nil, nil, errors.Wrapf(err, "failed to start shim")
 		}
@@ -73,12 +76,16 @@ func newCommand(binary string, config Config, socket *os.File) *exec.Cmd {
 	return cmd
 }
 
-func newSocket(config Config) (*os.File, error) {
-	l, err := sys.CreateUnixSocket(config.Address)
-	if err != nil {
-		return nil, err
+func newSocket(config Config) (*net.UnixListener, error) {
+	if len(config.Address) > 106 {
+		return nil, errors.Errorf("%q: unix socket path too long (limit 106)", config.Address)
 	}
-	return l.(*net.UnixListener).File()
+	l, err := net.Listen("unix", "\x00"+config.Address)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to listen to abstract unix socket %q", config.Address)
+	}
+
+	return l.(*net.UnixListener), nil
 }
 
 func connect(address string) (*grpc.ClientConn, error) {
@@ -98,7 +105,7 @@ func connect(address string) (*grpc.ClientConn, error) {
 
 func dialer(address string, timeout time.Duration) (net.Conn, error) {
 	address = strings.TrimPrefix(address, "unix://")
-	return net.DialTimeout("unix", address, timeout)
+	return net.DialTimeout("unix", "\x00"+address, timeout)
 }
 
 func dialAddress(address string) string {