fail on file not found for shim reconnect on containerd restart

Signed-off-by: Kathryn Baldauf <kabaldau@microsoft.com>

runtime/v2/shim/util_unix.go

@@ -78,6 +78,10 @@ func AnonDialer(address string, timeout time.Duration) (net.Conn, error) {
 	return net.DialTimeout("unix", "\x00"+address, timeout)
 }
 
+func AnonReconnectDialer(address string, timeout time.Duration) (net.Conn, error) {
+	return AnonDialer(address, timeout)
+}
+
 // NewSocket returns a new socket
 func NewSocket(address string) (*net.UnixListener, error) {
 	if len(address) > 106 {

runtime/v2/shim/util_windows.go

@@ -33,6 +33,22 @@ func getSysProcAttr() *syscall.SysProcAttr {
 	return nil
 }
 
+// AnonReconnectDialer returns a dialer for an existing npipe on containerd reconnection
+func AnonReconnectDialer(address string, timeout time.Duration) (net.Conn, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	c, err := winio.DialPipeContext(ctx, address)
+	if os.IsNotExist(err) {
+		return nil, errors.Wrap(os.ErrNotExist, "npipe not found on reconnect")
+	} else if err == context.DeadlineExceeded {
+		return nil, errors.Wrapf(err, "timed out waiting for npipe %s", address)
+	} else if err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
 // AnonDialer returns a dialer for a npipe
 func AnonDialer(address string, timeout time.Duration) (net.Conn, error) {
 	ctx, cancel := context.WithTimeout(context.Background(), timeout)