github.com/moby/docker@v26.1.3+incompatible/daemon/listeners/listeners_linux.go (about)

     1  package listeners // import "github.com/docker/docker/daemon/listeners"
     2  
     3  import (
     4  	"context"
     5  	"crypto/tls"
     6  	"net"
     7  	"os"
     8  	"strconv"
     9  
    10  	"github.com/containerd/log"
    11  	"github.com/coreos/go-systemd/v22/activation"
    12  	"github.com/docker/docker/pkg/homedir"
    13  	"github.com/docker/go-connections/sockets"
    14  	"github.com/pkg/errors"
    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  				log.G(context.TODO()).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, errors.Wrapf(err, "can't create unix socket %s", addr)
    49  		}
    50  		if _, err := homedir.StickRuntimeDirContents([]string{addr}); err != nil {
    51  			// StickRuntimeDirContents returns nil error if XDG_RUNTIME_DIR is just unset
    52  			log.G(context.TODO()).WithError(err).Warnf("cannot set sticky bit on socket %s under XDG_RUNTIME_DIR", addr)
    53  		}
    54  		ls = append(ls, l)
    55  	default:
    56  		return nil, errors.Errorf("invalid protocol format: %q", proto)
    57  	}
    58  
    59  	return ls, nil
    60  }
    61  
    62  // listenFD returns the specified socket activated files as a slice of
    63  // net.Listeners or all of the activated files if "*" is given.
    64  func listenFD(addr string, tlsConfig *tls.Config) ([]net.Listener, error) {
    65  	var (
    66  		err       error
    67  		listeners []net.Listener
    68  	)
    69  	// socket activation
    70  	if tlsConfig != nil {
    71  		listeners, err = activation.TLSListeners(tlsConfig)
    72  	} else {
    73  		listeners, err = activation.Listeners()
    74  	}
    75  	if err != nil {
    76  		return nil, err
    77  	}
    78  
    79  	if len(listeners) == 0 {
    80  		return nil, errors.New("no sockets found via socket activation: make sure the service was started by systemd")
    81  	}
    82  
    83  	// default to all fds just like unix:// and tcp://
    84  	if addr == "" || addr == "*" {
    85  		return listeners, nil
    86  	}
    87  
    88  	fdNum, err := strconv.Atoi(addr)
    89  	if err != nil {
    90  		return nil, errors.Errorf("failed to parse systemd fd address: should be a number: %v", addr)
    91  	}
    92  	fdOffset := fdNum - 3
    93  	if len(listeners) < fdOffset+1 {
    94  		return nil, errors.New("too few socket activated files passed in by systemd")
    95  	}
    96  	if listeners[fdOffset] == nil {
    97  		return nil, errors.Errorf("failed to listen on systemd activated file: fd %d", fdOffset+3)
    98  	}
    99  	for i, ls := range listeners {
   100  		if i == fdOffset || ls == nil {
   101  			continue
   102  		}
   103  		if err := ls.Close(); err != nil {
   104  			return nil, errors.Wrapf(err, "failed to close systemd activated file: fd %d", fdOffset+3)
   105  		}
   106  	}
   107  	return []net.Listener{listeners[fdOffset]}, nil
   108  }