1 files changed, 52 insertions, 0 deletions
diff --git a/sd_daemon/notify.go b/sd_daemon/notify.go
new file mode 100644
index 0000000..a038f54
--- /dev/null
+++ b/sd_daemon/notify.go
@@ -0,0 +1,52 @@
+// Copyright 2013-2015 Docker, Inc.
+// Copyright 2014 CoreOS, Inc.
+// Copyright 2015 Luke Shumaker
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sd_daemon
+
+import (
+	"errors"
+	"net"
+	"os"
+)
+
+// ErrNotifyNoSocket is an error returned if no socket was specified.
+var ErrNotifyNoSocket = errors.New("No socket")
+
+// Notify sends a message to the init daemon. It is common to ignore
+// the error.
+func Notify(unsetEnv bool, state string) error {
+	if unsetEnv {
+		defer os.Unsetenv("NOTIFY_SOCKET")
+	}
+
+	socketAddr := &net.UnixAddr{
+		Name: os.Getenv("NOTIFY_SOCKET"),
+		Net:  "unixgram",
+	}
+
+	if socketAddr.Name == "" {
+		return ErrNotifyNoSocket
+	}
+
+	conn, err := net.DialUnix(socketAddr.Net, nil, socketAddr)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	_, err = conn.Write([]byte(state))
+	return err
+}