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

diff --git a/sw/nanopi/cmd/stm/server.go b/sw/nanopi/cmd/stm/server.go
index 6b3bf16..d8c7764 100644 (file)
--- 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.