// +build !windows,!solaris

 package listeners

 
 import (

 	"crypto/tls"

 	"fmt"

 	"net"

 	"os"

 	"strconv"

 	"github.com/coreos/go-systemd/activation"

 	"github.com/docker/go-connections/sockets"

 	"github.com/sirupsen/logrus"

 )
 

 // Init creates new listeners for the server.

 // TODO: Clean up the fact that socketGroup and tlsConfig aren't always used.
 func Init(proto, addr, socketGroup string, tlsConfig *tls.Config) ([]net.Listener, error) {
 	ls := []net.Listener{}
 

 	switch proto {
 	case "fd":

 		fds, err := listenFD(addr, tlsConfig)

 		if err != nil {
 			return nil, err
 		}

 		ls = append(ls, fds...)

 	case "tcp":

 		l, err := sockets.NewTCPSocket(addr, tlsConfig)

 		if err != nil {

 			return nil, err
 		}

 		ls = append(ls, l)

 	case "unix":

 		gid, err := lookupGID(socketGroup)

 		if err != nil {

 			if socketGroup != "" {
 				if socketGroup != defaultSocketGroup {
 					return nil, err
 				}
 				logrus.Warnf("could not change group %s to %s: %v", addr, defaultSocketGroup, err)

 			}
 			gid = os.Getgid()

 		}
 		l, err := sockets.NewUnixSocket(addr, gid)

 		if err != nil {

 			return nil, fmt.Errorf("can't create unix socket %s: %v", addr, err)

 		}

 		ls = append(ls, l)

 	default:

 		return nil, fmt.Errorf("invalid protocol format: %q", proto)

 	}
 

 	return ls, nil

 }

 // listenFD returns the specified socket activated files as a slice of
 // net.Listeners or all of the activated files if "*" is given.

 func listenFD(addr string, tlsConfig *tls.Config) ([]net.Listener, error) {
 	var (
 		err       error
 		listeners []net.Listener
 	)

 	// socket activation

 	if tlsConfig != nil {

 		listeners, err = activation.TLSListeners(false, tlsConfig)

 	} else {

 		listeners, err = activation.Listeners(false)

 	}

 	if err != nil {
 		return nil, err
 	}
 

 	if len(listeners) == 0 {

 		return nil, fmt.Errorf("no sockets found via socket activation: make sure the service was started by systemd")

 	}
 
 	// default to all fds just like unix:// and tcp://

 	if addr == "" || addr == "*" {
 		return listeners, nil

 	}
 

 	fdNum, err := strconv.Atoi(addr)
 	if err != nil {

 		return nil, fmt.Errorf("failed to parse systemd fd address: should be a number: %v", addr)

 	}

 	fdOffset := fdNum - 3

 	if len(listeners) < int(fdOffset)+1 {

 		return nil, fmt.Errorf("too few socket activated files passed in by systemd")

 	}

 	if listeners[fdOffset] == nil {

 		return nil, fmt.Errorf("failed to listen on systemd activated file: fd %d", fdOffset+3)

 	}
 	for i, ls := range listeners {
 		if i == fdOffset || ls == nil {
 			continue
 		}
 		if err := ls.Close(); err != nil {

 			return nil, fmt.Errorf("failed to close systemd activated file: fd %d: %v", fdOffset+3, err)

 		}

 	}
 	return []net.Listener{listeners[fdOffset]}, nil
 }