added systemd socket activation

Makefile

@@ -0,0 +1,39 @@
+##
+## Copyright (c) 2016 Christian Pointner <equinox@realraum.at>
+## All rights reserved.
+##
+## Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are met:
+##     * Redistributions of source code must retain the above copyright
+##       notice, this list of conditions and the following disclaimer.
+##     * Redistributions in binary form must reproduce the above copyright
+##       notice, this list of conditions and the following disclaimer in the
+##       documentation and/or other materials provided with the distribution.
+##     * Neither the name of telgo nor the names of its contributors may be
+##       used to endorse or promote products derived from this software without
+##       specific prior written permission.
+##
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+## ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+## WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+## DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+## FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+## DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+## SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+## CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+## OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+##
+
+GOCMD := go
+ifdef GOROOT
+GOCMD = $(GOROOT)/bin/go
+endif
+
+bin:
+	$(GOCMD) build -tags netgo
+
+clean:
+	rm -f telme10
+
+.PHONY: bin clean

main.go

@@ -31,9 +31,11 @@ package main
 
 import (
 	"fmt"
-	"github.com/spreadspace/telgo"
 	"os"
 	"time"
+
+	"github.com/coreos/go-systemd/activation"
+	"github.com/spreadspace/telgo"
 )
 
 func greet(c *telgo.Client, args []string) bool {
@@ -84,10 +86,29 @@ func greet(c *telgo.Client, args []string) bool {
 func main() {
 	cmdlist := make(telgo.CmdList)
 
-	s, err := telgo.NewServer(":7023", "", cmdlist, nil)
+	listeners, err := activation.Listeners(true)
 	if err != nil {
-		fmt.Println("failed to initialize the server:", err)
-		os.Exit(1)
+	}
+
+	fmt.Printf("got %d sockets from systemd\n", len(listeners))
+	var s *telgo.Server
+	if len(listeners) == 0 {
+		if len(os.Args) < 2 {
+			fmt.Println("please specify a address to listen on")
+			os.Exit(2)
+		}
+		if s, err = telgo.NewServer(os.Args[1], "", cmdlist, nil); err != nil {
+			fmt.Println("failed to initialize the server:", err)
+			os.Exit(1)
+		}
+	} else {
+		if len(listeners) > 1 {
+			fmt.Println("warning got more than one socket from systemd, only using the first", err)
+		}
+		if s, err = telgo.NewServerFromListener(listeners[0], "", cmdlist, nil); err != nil {
+			fmt.Println("failed to initialize the server:", err)
+			os.Exit(1)
+		}
 	}
 	if err = s.RunWithGreeter(greet); err != nil {
 		fmt.Println("telnet server returned:", err)

telme10.service

@@ -0,0 +1,16 @@
+[Unit]
+Description=realraum birthday telnet server
+After=local-fs.target
+
+[Service]
+User=telme10
+Group=telme10
+Type=simple
+ExecStart=/usr/local/bin/telme10
+PrivateTmp=yes
+PrivateDevices=yes
+ProtectSystem=full
+ProtectHome=yes
+
+[Install]
+WantedBy=multi-user.target

telme10.socket

@@ -0,0 +1,8 @@
+[Unit]
+Description=realraum birthday telnet server socket
+
+[Socket]
+ListenStream=23
+
+[Install]
+WantedBy=sockets.target