github.com/hms58/moby@v1.13.1/pkg/listeners/listeners_unix.go (about)

     1  // +build !windows,!solaris
     2  
     3  package listeners
     4  
     5  import (
     6  	"crypto/tls"
     7  	"fmt"
     8  	"net"
     9  	"strconv"
    10  
    11  	"github.com/Sirupsen/logrus"
    12  	"github.com/coreos/go-systemd/activation"
    13  	"github.com/docker/go-connections/sockets"
    14  )
    15  
    16  // Init creates new listeners for the server.
    17  // TODO: Clean up the fact that socketGroup and tlsConfig aren't always used.
    18  func Init(proto, addr, socketGroup string, tlsConfig *tls.Config) ([]net.Listener, error) {
    19  	ls := []net.Listener{}
    20  
    21  	switch proto {
    22  	case "fd":
    23  		fds, err := listenFD(addr, tlsConfig)
    24  		if err != nil {
    25  			return nil, err
    26  		}
    27  		ls = append(ls, fds...)
    28  	case "tcp":
    29  		l, err := sockets.NewTCPSocket(addr, tlsConfig)
    30  		if err != nil {
    31  			return nil, err
    32  		}
    33  		ls = append(ls, l)
    34  	case "unix":
    35  		l, err := sockets.NewUnixSocket(addr, socketGroup)
    36  		if err != nil {
    37  			return nil, fmt.Errorf("can't create unix socket %s: %v", addr, err)
    38  		}
    39  		ls = append(ls, l)
    40  	default:
    41  		return nil, fmt.Errorf("invalid protocol format: %q", proto)
    42  	}
    43  
    44  	return ls, nil
    45  }
    46  
    47  // listenFD returns the specified socket activated files as a slice of
    48  // net.Listeners or all of the activated files if "*" is given.
    49  func listenFD(addr string, tlsConfig *tls.Config) ([]net.Listener, error) {
    50  	var (
    51  		err       error
    52  		listeners []net.Listener
    53  	)
    54  	// socket activation
    55  	if tlsConfig != nil {
    56  		listeners, err = activation.TLSListeners(false, tlsConfig)
    57  	} else {
    58  		listeners, err = activation.Listeners(false)
    59  	}
    60  	if err != nil {
    61  		return nil, err
    62  	}
    63  
    64  	if len(listeners) == 0 {
    65  		return nil, fmt.Errorf("no sockets found via socket activation: make sure the service was started by systemd")
    66  	}
    67  
    68  	// default to all fds just like unix:// and tcp://
    69  	if addr == "" || addr == "*" {
    70  		return listeners, nil
    71  	}
    72  
    73  	fdNum, err := strconv.Atoi(addr)
    74  	if err != nil {
    75  		return nil, fmt.Errorf("failed to parse systemd fd address: should be a number: %v", addr)
    76  	}
    77  	fdOffset := fdNum - 3
    78  	if len(listeners) < int(fdOffset)+1 {
    79  		return nil, fmt.Errorf("too few socket activated files passed in by systemd")
    80  	}
    81  	if listeners[fdOffset] == nil {
    82  		return nil, fmt.Errorf("failed to listen on systemd activated file: fd %d", fdOffset+3)
    83  	}
    84  	for i, ls := range listeners {
    85  		if i == fdOffset || ls == nil {
    86  			continue
    87  		}
    88  		if err := ls.Close(); err != nil {
    89  			// TODO: We shouldn't log inside a library. Remove this or error out.
    90  			logrus.Errorf("failed to close systemd activated file: fd %d: %v", fdOffset+3, err)
    91  		}
    92  	}
    93  	return []net.Listener{listeners[fdOffset]}, nil
    94  }