daemon: SdNotify: add support for abstract unix sockets

As per https://www.freedesktop.org/software/systemd/man/latest/sd_notify.html#

daemon/sdnotify.go

@@ -54,14 +54,28 @@ const (
 // (false, err) - notification supported, but failure happened (e.g. error connecting to NOTIFY_SOCKET or while sending data)
 // (true, nil) - notification supported, data has been sent
 func SdNotify(unsetEnvironment bool, state string) (bool, error) {
- socketAddr := &net.UnixAddr{
- Name: os.Getenv("NOTIFY_SOCKET"),
- Net: "unixgram",
- }
+ notifySocket := os.Getenv("NOTIFY_SOCKET")
 
  // NOTIFY_SOCKET not set
- if socketAddr.Name == "" {
+ if notifySocket == "" {
  return false, nil
+ }
+
+ // socket type not supported. We only support unix domain sockets
+ // but NOTIFY_SOCKET can also use vsock
+ if notifySocket[0] != '@' || notifySocket[0] != '/' {
+ return false, nil
+ }
+
+
+ // abstract unix socket. Start with a 0-byte
+ if notifySocket[0] == '@' {
+ notifySocket = "\00" ++ notifySocket[1:]
+ }
+
+ socketAddr := &net.UnixAddr{
+ Name: notifySocket,
+ Net: "unixgram",
  }
 
  if unsetEnvironment {