github.com/hustcat/docker@v1.3.3-0.20160314103604-901c67a8eeab/docker/listeners/listeners_unix.go (about)

     1  // +build !windows
     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  	"github.com/docker/libnetwork/portallocator"
    15  )
    16  
    17  // Init creates new listeners for the server.
    18  func Init(proto, addr, socketGroup string, tlsConfig *tls.Config) (ls []net.Listener, err error) {
    19  	switch proto {
    20  	case "fd":
    21  		ls, err = listenFD(addr, tlsConfig)
    22  		if err != nil {
    23  			return nil, err
    24  		}
    25  	case "tcp":
    26  		l, err := initTCPSocket(addr, tlsConfig)
    27  		if err != nil {
    28  			return nil, err
    29  		}
    30  		ls = append(ls, l)
    31  	case "unix":
    32  		l, err := sockets.NewUnixSocket(addr, socketGroup)
    33  		if err != nil {
    34  			return nil, fmt.Errorf("can't create unix socket %s: %v", addr, err)
    35  		}
    36  		ls = append(ls, l)
    37  	default:
    38  		return nil, fmt.Errorf("Invalid protocol format: %q", proto)
    39  	}
    40  
    41  	return
    42  }
    43  
    44  // listenFD returns the specified socket activated files as a slice of
    45  // net.Listeners or all of the activated files if "*" is given.
    46  func listenFD(addr string, tlsConfig *tls.Config) ([]net.Listener, error) {
    47  	var (
    48  		err       error
    49  		listeners []net.Listener
    50  	)
    51  	// socket activation
    52  	if tlsConfig != nil {
    53  		listeners, err = activation.TLSListeners(false, tlsConfig)
    54  	} else {
    55  		listeners, err = activation.Listeners(false)
    56  	}
    57  	if err != nil {
    58  		return nil, err
    59  	}
    60  
    61  	if len(listeners) == 0 {
    62  		return nil, fmt.Errorf("No sockets found. Make sure the docker daemon was started by systemd.")
    63  	}
    64  
    65  	// default to all fds just like unix:// and tcp://
    66  	if addr == "" || addr == "*" {
    67  		return listeners, nil
    68  	}
    69  
    70  	fdNum, err := strconv.Atoi(addr)
    71  	if err != nil {
    72  		return nil, fmt.Errorf("failed to parse systemd address, should be number: %v", err)
    73  	}
    74  	fdOffset := fdNum - 3
    75  	if len(listeners) < int(fdOffset)+1 {
    76  		return nil, fmt.Errorf("Too few socket activated files passed in")
    77  	}
    78  	if listeners[fdOffset] == nil {
    79  		return nil, fmt.Errorf("failed to listen on systemd activated file at fd %d", fdOffset+3)
    80  	}
    81  	for i, ls := range listeners {
    82  		if i == fdOffset || ls == nil {
    83  			continue
    84  		}
    85  		if err := ls.Close(); err != nil {
    86  			logrus.Errorf("Failed to close systemd activated file at fd %d: %v", fdOffset+3, err)
    87  		}
    88  	}
    89  	return []net.Listener{listeners[fdOffset]}, nil
    90  }
    91  
    92  // allocateDaemonPort ensures that there are no containers
    93  // that try to use any port allocated for the docker server.
    94  func allocateDaemonPort(addr string) error {
    95  	host, port, err := net.SplitHostPort(addr)
    96  	if err != nil {
    97  		return err
    98  	}
    99  
   100  	intPort, err := strconv.Atoi(port)
   101  	if err != nil {
   102  		return err
   103  	}
   104  
   105  	var hostIPs []net.IP
   106  	if parsedIP := net.ParseIP(host); parsedIP != nil {
   107  		hostIPs = append(hostIPs, parsedIP)
   108  	} else if hostIPs, err = net.LookupIP(host); err != nil {
   109  		return fmt.Errorf("failed to lookup %s address in host specification", host)
   110  	}
   111  
   112  	pa := portallocator.Get()
   113  	for _, hostIP := range hostIPs {
   114  		if _, err := pa.RequestPort(hostIP, "tcp", intPort); err != nil {
   115  			return fmt.Errorf("failed to allocate daemon listening port %d (err: %v)", intPort, err)
   116  		}
   117  	}
   118  	return nil
   119  }