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moby--moby/api/client/hijack.go

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package client
import (
"crypto/tls"
"errors"
"fmt"
"io"
"net"
"net/http"
"net/http/httputil"
"os"
"runtime"
"strings"
"time"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/api"
"github.com/docker/docker/autogen/dockerversion"
"github.com/docker/docker/pkg/promise"
"github.com/docker/docker/pkg/stdcopy"
"github.com/docker/docker/pkg/term"
)
type tlsClientCon struct {
*tls.Conn
rawConn net.Conn
}
func (c *tlsClientCon) CloseWrite() error {
// Go standard tls.Conn doesn't provide the CloseWrite() method so we do it
// on its underlying connection.
if cwc, ok := c.rawConn.(interface {
CloseWrite() error
}); ok {
return cwc.CloseWrite()
}
return nil
}
func tlsDial(network, addr string, config *tls.Config) (net.Conn, error) {
return tlsDialWithDialer(new(net.Dialer), network, addr, config)
}
// We need to copy Go's implementation of tls.Dial (pkg/cryptor/tls/tls.go) in
// order to return our custom tlsClientCon struct which holds both the tls.Conn
// object _and_ its underlying raw connection. The rationale for this is that
// we need to be able to close the write end of the connection when attaching,
// which tls.Conn does not provide.
func tlsDialWithDialer(dialer *net.Dialer, network, addr string, config *tls.Config) (net.Conn, error) {
// We want the Timeout and Deadline values from dialer to cover the
// whole process: TCP connection and TLS handshake. This means that we
// also need to start our own timers now.
timeout := dialer.Timeout
if !dialer.Deadline.IsZero() {
deadlineTimeout := dialer.Deadline.Sub(time.Now())
if timeout == 0 || deadlineTimeout < timeout {
timeout = deadlineTimeout
}
}
var errChannel chan error
if timeout != 0 {
errChannel = make(chan error, 2)
time.AfterFunc(timeout, func() {
errChannel <- errors.New("")
})
}
rawConn, err := dialer.Dial(network, addr)
if err != nil {
return nil, err
}
// When we set up a TCP connection for hijack, there could be long periods
// of inactivity (a long running command with no output) that in certain
// network setups may cause ECONNTIMEOUT, leaving the client in an unknown
// state. Setting TCP KeepAlive on the socket connection will prohibit
// ECONNTIMEOUT unless the socket connection truly is broken
if tcpConn, ok := rawConn.(*net.TCPConn); ok {
tcpConn.SetKeepAlive(true)
tcpConn.SetKeepAlivePeriod(30 * time.Second)
}
colonPos := strings.LastIndex(addr, ":")
if colonPos == -1 {
colonPos = len(addr)
}
hostname := addr[:colonPos]
// If no ServerName is set, infer the ServerName
// from the hostname we're connecting to.
if config.ServerName == "" {
// Make a copy to avoid polluting argument or default.
c := *config
c.ServerName = hostname
config = &c
}
conn := tls.Client(rawConn, config)
if timeout == 0 {
err = conn.Handshake()
} else {
go func() {
errChannel <- conn.Handshake()
}()
err = <-errChannel
}
if err != nil {
rawConn.Close()
return nil, err
}
// This is Docker difference with standard's crypto/tls package: returned a
// wrapper which holds both the TLS and raw connections.
return &tlsClientCon{conn, rawConn}, nil
}
func (cli *DockerCli) dial() (net.Conn, error) {
if cli.tlsConfig != nil && cli.proto != "unix" {
// Notice this isn't Go standard's tls.Dial function
return tlsDial(cli.proto, cli.addr, cli.tlsConfig)
}
return net.Dial(cli.proto, cli.addr)
}
func (cli *DockerCli) hijack(method, path string, setRawTerminal bool, in io.ReadCloser, stdout, stderr io.Writer, started chan io.Closer, data interface{}) error {
defer func() {
if started != nil {
close(started)
}
}()
params, err := cli.encodeData(data)
if err != nil {
return err
}
req, err := http.NewRequest(method, fmt.Sprintf("%s/v%s%s", cli.basePath, api.Version, path), params)
if err != nil {
return err
}
// Add CLI Config's HTTP Headers BEFORE we set the Docker headers
// then the user can't change OUR headers
for k, v := range cli.configFile.HTTPHeaders {
req.Header.Set(k, v)
}
req.Header.Set("User-Agent", "Docker-Client/"+dockerversion.VERSION+" ("+runtime.GOOS+")")
req.Header.Set("Content-Type", "text/plain")
req.Header.Set("Connection", "Upgrade")
req.Header.Set("Upgrade", "tcp")
req.Host = cli.addr
dial, err := cli.dial()
// When we set up a TCP connection for hijack, there could be long periods
// of inactivity (a long running command with no output) that in certain
// network setups may cause ECONNTIMEOUT, leaving the client in an unknown
// state. Setting TCP KeepAlive on the socket connection will prohibit
// ECONNTIMEOUT unless the socket connection truly is broken
if tcpConn, ok := dial.(*net.TCPConn); ok {
tcpConn.SetKeepAlive(true)
tcpConn.SetKeepAlivePeriod(30 * time.Second)
}
if err != nil {
if strings.Contains(err.Error(), "connection refused") {
return fmt.Errorf("Cannot connect to the Docker daemon. Is 'docker daemon' running on this host?")
}
return err
}
clientconn := httputil.NewClientConn(dial, nil)
defer clientconn.Close()
// Server hijacks the connection, error 'connection closed' expected
clientconn.Do(req)
rwc, br := clientconn.Hijack()
defer rwc.Close()
if started != nil {
started <- rwc
}
var receiveStdout chan error
var oldState *term.State
if in != nil && setRawTerminal && cli.isTerminalIn && os.Getenv("NORAW") == "" {
oldState, err = term.SetRawTerminal(cli.inFd)
if err != nil {
return err
}
defer term.RestoreTerminal(cli.inFd, oldState)
}
if stdout != nil || stderr != nil {
receiveStdout = promise.Go(func() (err error) {
defer func() {
if in != nil {
if setRawTerminal && cli.isTerminalIn {
term.RestoreTerminal(cli.inFd, oldState)
}
// For some reason this Close call blocks on darwin..
// As the client exists right after, simply discard the close
// until we find a better solution.
if runtime.GOOS != "darwin" {
in.Close()
}
}
}()
// When TTY is ON, use regular copy
if setRawTerminal && stdout != nil {
_, err = io.Copy(stdout, br)
} else {
_, err = stdcopy.StdCopy(stdout, stderr, br)
}
logrus.Debugf("[hijack] End of stdout")
return err
})
}
sendStdin := promise.Go(func() error {
if in != nil {
io.Copy(rwc, in)
logrus.Debugf("[hijack] End of stdin")
}
if conn, ok := rwc.(interface {
CloseWrite() error
}); ok {
if err := conn.CloseWrite(); err != nil {
logrus.Debugf("Couldn't send EOF: %s", err)
}
}
// Discard errors due to pipe interruption
return nil
})
if stdout != nil || stderr != nil {
if err := <-receiveStdout; err != nil {
logrus.Debugf("Error receiveStdout: %s", err)
return err
}
}
if !cli.isTerminalIn {
if err := <-sendStdin; err != nil {
logrus.Debugf("Error sendStdin: %s", err)
return err
}
}
return nil
}