Only attempt to use systemd on linux

Remove plan9 builds

.travis.yml

@@ -14,9 +14,6 @@ script:
   - curl -L https://download.dnscrypt.info/tools/upx-linux > upx
   - chmod +x upx
 
-  - go clean
-  - env GOOS=plan9 go build -ldflags="-s -w" && ./upx --lzma --best dnscrypt-proxy
-
   - go clean
   - env GOOS=solaris go build -ldflags="-s -w" && ./upx --lzma --best dnscrypt-proxy
 

dnscrypt-proxy/main.go

@@ -10,8 +10,6 @@ import (
 	"sync"
 	"time"
 
-	"github.com/coreos/go-systemd/activation"
-	"github.com/coreos/go-systemd/daemon"
 	"github.com/jedisct1/dlog"
 	"github.com/kardianos/service"
 	"golang.org/x/crypto/curve25519"
@@ -166,13 +164,13 @@ func (proxy *Proxy) StartProxy() {
 			dlog.Fatal(err)
 		}
 	}
-	if err := proxy.systemDListeners(); err != nil {
+	if err := proxy.SystemDListeners(); err != nil {
 		dlog.Fatal(err)
 	}
 	liveServers, err := proxy.serversInfo.refresh(proxy)
 	if liveServers > 0 {
 		dlog.Noticef("dnscrypt-proxy is ready - live servers: %d", liveServers)
-		daemon.SdNotify(false, "READY=1")
+		SystemDNotify()
 	} else if err != nil {
 		dlog.Error(err)
 		dlog.Notice("dnscrypt-proxy is waiting for at least one server to be reachable")
@@ -265,24 +263,6 @@ func (proxy *Proxy) tcpListenerFromAddr(listenAddr *net.TCPAddr) error {
 	return nil
 }
 
-func (proxy *Proxy) systemDListeners() error {
-	listeners, err := activation.Listeners(true)
-	if err != nil && len(listeners) > 0 {
-		for i, listener := range listeners {
-			dlog.Noticef("Wiring systemd TCP socket #%d", i)
-			proxy.tcpListener(listener.(*net.TCPListener))
-		}
-	}
-	packetConns, err := activation.PacketConns(true)
-	if err != nil && len(packetConns) > 0 {
-		for i, packetConn := range packetConns {
-			dlog.Noticef("Wiring systemd UDP socket #%d", i)
-			proxy.udpListener(packetConn.(*net.UDPConn))
-		}
-	}
-	return nil
-}
-
 func (proxy *Proxy) exchangeWithUDPServer(serverInfo *ServerInfo, encryptedQuery []byte, clientNonce []byte) ([]byte, error) {
 	pc, err := net.DialUDP("udp", nil, serverInfo.UDPAddr)
 	if err != nil {

dnscrypt-proxy/systemd_free.go

@@ -0,0 +1,9 @@
+// +build !linux
+
+package main
+
+func (proxy *Proxy) SystemDListeners() error {
+	return nil
+}
+
+func SystemDNotify() {}

dnscrypt-proxy/systemd_linux.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"net"
+
+	"github.com/coreos/go-systemd/activation"
+	"github.com/coreos/go-systemd/daemon"
+	"github.com/jedisct1/dlog"
+)
+
+func (proxy *Proxy) SystemDListeners() error {
+	listeners, err := activation.Listeners(true)
+	if err != nil && len(listeners) > 0 {
+		for i, listener := range listeners {
+			dlog.Noticef("Wiring systemd TCP socket #%d", i)
+			proxy.tcpListener(listener.(*net.TCPListener))
+		}
+	}
+	packetConns, err := activation.PacketConns(true)
+	if err != nil && len(packetConns) > 0 {
+		for i, packetConn := range packetConns {
+			dlog.Noticef("Wiring systemd UDP socket #%d", i)
+			proxy.udpListener(packetConn.(*net.UDPConn))
+		}
+	}
+	return nil
+}
+
+func SystemDNotify() {
+	daemon.SdNotify(false, "READY=1")
+}