commit 6d59201bde6fdd81402356a9e67dbb5ab9747b1d
Author: Solomon Hykes <solomon@dotcloud.com>
Date:   Mon Dec 23 23:07:01 2013 +0000

    Move utility package 'systemd' to pkg/systemd

diff --git a/systemd/sd_notify.go b/systemd/sd_notify.go
new file mode 100644
index 0000000..1993cab
--- /dev/null
+++ b/systemd/sd_notify.go
@@ -0,0 +1,33 @@
+package systemd
+
+import (
+	"errors"
+	"net"
+	"os"
+)
+
+var SdNotifyNoSocket = errors.New("No socket")
+
+// Send a message to the init daemon. It is common to ignore the error.
+func SdNotify(state string) error {
+	socketAddr := &net.UnixAddr{
+		Name: os.Getenv("NOTIFY_SOCKET"),
+		Net:  "unixgram",
+	}
+
+	if socketAddr.Name == "" {
+		return SdNotifyNoSocket
+	}
+
+	conn, err := net.DialUnix(socketAddr.Net, nil, socketAddr)
+	if err != nil {
+		return err
+	}
+
+	_, err = conn.Write([]byte(state))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}