github.com/lazyboychen7/engine@v17.12.1-ce-rc2+incompatible/daemon/listeners/listeners_unix.go (about)

     1  // +build !windows
     2  
     3  package listeners
     4  
     5  import (
     6  	"crypto/tls"
     7  	"fmt"
     8  	"net"
     9  	"os"
    10  	"strconv"
    11  
    12  	"github.com/coreos/go-systemd/activation"
    13  	"github.com/docker/go-connections/sockets"
    14  	"github.com/sirupsen/logrus"
    15  )
    16  
    17  // Init creates new listeners for the server.
    18  // TODO: Clean up the fact that socketGroup and tlsConfig aren't always used.
    19  func Init(proto, addr, socketGroup string, tlsConfig *tls.Config) ([]net.Listener, error) {
    20  	ls := []net.Listener{}
    21  
    22  	switch proto {
    23  	case "fd":
    24  		fds, err := listenFD(addr, tlsConfig)
    25  		if err != nil {
    26  			return nil, err
    27  		}
    28  		ls = append(ls, fds...)
    29  	case "tcp":
    30  		l, err := sockets.NewTCPSocket(addr, tlsConfig)
    31  		if err != nil {
    32  			return nil, err
    33  		}
    34  		ls = append(ls, l)
    35  	case "unix":
    36  		gid, err := lookupGID(socketGroup)
    37  		if err != nil {
    38  			if socketGroup != "" {
    39  				if socketGroup != defaultSocketGroup {
    40  					return nil, err
    41  				}
    42  				logrus.Warnf("could not change group %s to %s: %v", addr, defaultSocketGroup, err)
    43  			}
    44  			gid = os.Getgid()
    45  		}
    46  		l, err := sockets.NewUnixSocket(addr, gid)
    47  		if err != nil {
    48  			return nil, fmt.Errorf("can't create unix socket %s: %v", addr, err)
    49  		}
    50  		ls = append(ls, l)
    51  	default:
    52  		return nil, fmt.Errorf("invalid protocol format: %q", proto)
    53  	}
    54  
    55  	return ls, nil
    56  }
    57  
    58  // listenFD returns the specified socket activated files as a slice of
    59  // net.Listeners or all of the activated files if "*" is given.
    60  func listenFD(addr string, tlsConfig *tls.Config) ([]net.Listener, error) {
    61  	var (
    62  		err       error
    63  		listeners []net.Listener
    64  	)
    65  	// socket activation
    66  	if tlsConfig != nil {
    67  		listeners, err = activation.TLSListeners(false, tlsConfig)
    68  	} else {
    69  		listeners, err = activation.Listeners(false)
    70  	}
    71  	if err != nil {
    72  		return nil, err
    73  	}
    74  
    75  	if len(listeners) == 0 {
    76  		return nil, fmt.Errorf("no sockets found via socket activation: make sure the service was started by systemd")
    77  	}
    78  
    79  	// default to all fds just like unix:// and tcp://
    80  	if addr == "" || addr == "*" {
    81  		return listeners, nil
    82  	}
    83  
    84  	fdNum, err := strconv.Atoi(addr)
    85  	if err != nil {
    86  		return nil, fmt.Errorf("failed to parse systemd fd address: should be a number: %v", addr)
    87  	}
    88  	fdOffset := fdNum - 3
    89  	if len(listeners) < fdOffset+1 {
    90  		return nil, fmt.Errorf("too few socket activated files passed in by systemd")
    91  	}
    92  	if listeners[fdOffset] == nil {
    93  		return nil, fmt.Errorf("failed to listen on systemd activated file: fd %d", fdOffset+3)
    94  	}
    95  	for i, ls := range listeners {
    96  		if i == fdOffset || ls == nil {
    97  			continue
    98  		}
    99  		if err := ls.Close(); err != nil {
   100  			return nil, fmt.Errorf("failed to close systemd activated file: fd %d: %v", fdOffset+3, err)
   101  		}
   102  	}
   103  	return []net.Listener{listeners[fdOffset]}, nil
   104  }