From 60fee87ba16ba08618e28db1a3a696646d418e1b Mon Sep 17 00:00:00 2001
From: Aleksander Mistewicz <a.mistewicz@samsung.com>
Date: Fri, 16 Feb 2018 17:42:45 +0100
Subject: [PATCH] Add systemd integration to stm executable

stm binary is intended to be started in a server mode as a service.
It is possible for systemd to wait for a connection on a socket
and start a service only when such connection is established.

Change-Id: Ica5374312679f8935f2b896e142c5ea63a76728c
---
 sw/nanopi/cmd/stm/server.go | 33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/sw/nanopi/cmd/stm/server.go b/sw/nanopi/cmd/stm/server.go
index 6b3bf16..d8c7764 100644
--- a/sw/nanopi/cmd/stm/server.go
+++ b/sw/nanopi/cmd/stm/server.go
@@ -24,6 +24,7 @@ import (
 	"os/signal"
 
 	"git.tizen.org/tools/muxpi/sw/nanopi/stm"
+	"github.com/coreos/go-systemd/activation"
 )
 
 func registerUserServiceOnListener(impl stm.UserInterface, l net.Listener) {
@@ -57,13 +58,31 @@ func registerService(i stm.Interface, path string) net.Listener {
 }
 
 func serveRemoteSTM(dev stm.Interface) {
-	if userServiceSocket != "" {
-		l := registerUserService(dev.(stm.UserInterface), userServiceSocket)
-		defer l.Close()
-	}
-	if serviceSocket != "" {
-		l := registerService(dev, serviceSocket)
-		defer l.Close()
+	listeners, err := activation.Listeners()
+	if err != nil {
+		if userServiceSocket != "" {
+			l := registerUserService(dev.(stm.UserInterface), userServiceSocket)
+			defer l.Close()
+		}
+		if serviceSocket != "" {
+			l := registerService(dev, serviceSocket)
+			defer l.Close()
+		}
+	} else if len(listeners) == 2 {
+		for _, l := range listeners {
+			name := l.Addr().String()
+			switch {
+			case serviceSocket != "" && name == serviceSocket:
+				registerServiceOnListener(dev, l)
+			case userServiceSocket != "" && name == userServiceSocket:
+				registerUserServiceOnListener(dev.(stm.UserInterface), l)
+			default:
+				log.Fatal("unknown fd name: ", name)
+			}
+			defer l.Close()
+		}
+	} else {
+		log.Fatal("unexpected number of file descriptors passed: ", len(listeners))
 	}
 
 	// Wait for interrupt.
-- 
2.7.4