// the process for execing a new process inside an existing container is that we have to exec ourself
// with the nsenter argument so that the C code can setns an the namespaces that we require. Then that
// code path will drop us into the path that we can do the final setup of the namespace and exec the users
// application.
func startInExistingContainer(config *libcontainer.Config, state *libcontainer.State, action string, context *cli.Context) (int, error) {
var (
master *os.File
console string
err error
sigc = make(chan os.Signal, 10)
stdin = os.Stdin
stdout = os.Stdout
stderr = os.Stderr
)
signal.Notify(sigc)
if config.Tty {
stdin = nil
stdout = nil
stderr = nil
master, console, err = consolepkg.CreateMasterAndConsole()
if err != nil {
return -1, err
}
go io.Copy(master, os.Stdin)
go io.Copy(os.Stdout, master)
state, err := term.SetRawTerminal(os.Stdin.Fd())
if err != nil {
return -1, err
}
defer term.RestoreTerminal(os.Stdin.Fd(), state)
}
startCallback := func(cmd *exec.Cmd) {
go func() {
resizeTty(master)
for sig := range sigc {
switch sig {
case syscall.SIGWINCH:
resizeTty(master)
default:
cmd.Process.Signal(sig)
}
}
}()
}
return namespaces.ExecIn(config, state, context.Args(), os.Args[0], action, stdin, stdout, stderr, console, startCallback)
}
func (cli *DockerCli) hijack(method, path string, setRawTerminal bool, in io.ReadCloser, stdout, stderr io.Writer, started chan io.Closer) error {
defer func() {
if started != nil {
close(started)
}
}()
req, err := http.NewRequest(method, fmt.Sprintf("/v%s%s", api.APIVERSION, path), nil)
if err != nil {
return err
}
req.Header.Set("User-Agent", "Docker-Client/"+dockerversion.VERSION)
req.Header.Set("Content-Type", "plain/text")
req.Host = cli.addr
dial, err := cli.dial()
if err != nil {
if strings.Contains(err.Error(), "connection refused") {
return fmt.Errorf("Cannot connect to the Docker daemon. Is 'docker -d' 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.isTerminal && os.Getenv("NORAW") == "" {
oldState, err = term.SetRawTerminal(cli.terminalFd)
if err != nil {
return err
}
defer term.RestoreTerminal(cli.terminalFd, oldState)
}
if stdout != nil || stderr != nil {
receiveStdout = utils.Go(func() (err error) {
defer func() {
if in != nil {
if setRawTerminal && cli.isTerminal {
term.RestoreTerminal(cli.terminalFd, 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 = utils.StdCopy(stdout, stderr, br)
}
log.Debugf("[hijack] End of stdout")
return err
})
}
sendStdin := utils.Go(func() error {
if in != nil {
io.Copy(rwc, in)
log.Debugf("[hijack] End of stdin")
}
if tcpc, ok := rwc.(*net.TCPConn); ok {
if err := tcpc.CloseWrite(); err != nil {
log.Debugf("Couldn't send EOF: %s", err)
}
} else if unixc, ok := rwc.(*net.UnixConn); ok {
if err := unixc.CloseWrite(); err != nil {
log.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 {
log.Debugf("Error receiveStdout: %s", err)
return err
}
}
if !cli.isTerminal {
if err := <-sendStdin; err != nil {
log.Debugf("Error sendStdin: %s", err)
return err
}
}
return nil
}
// startContainer starts the container. Returns the exit status or -1 and an
// error.
//
// Signals sent to the current process will be forwarded to container.
func startContainer(container *libcontainer.Config, dataPath string, args []string) (int, error) {
var (
cmd *exec.Cmd
sigc = make(chan os.Signal, 10)
)
signal.Notify(sigc)
createCommand := func(container *libcontainer.Config, console, rootfs, dataPath, init string, pipe *os.File, args []string) *exec.Cmd {
cmd = namespaces.DefaultCreateCommand(container, console, rootfs, dataPath, init, pipe, args)
if logPath != "" {
cmd.Env = append(cmd.Env, fmt.Sprintf("log=%s", logPath))
}
return cmd
}
var (
master *os.File
console string
err error
stdin = os.Stdin
stdout = os.Stdout
stderr = os.Stderr
)
if container.Tty {
stdin = nil
stdout = nil
stderr = nil
master, console, err = consolepkg.CreateMasterAndConsole()
if err != nil {
return -1, err
}
go io.Copy(master, os.Stdin)
go io.Copy(os.Stdout, master)
state, err := term.SetRawTerminal(os.Stdin.Fd())
if err != nil {
return -1, err
}
defer term.RestoreTerminal(os.Stdin.Fd(), state)
}
startCallback := func() {
go func() {
resizeTty(master)
for sig := range sigc {
switch sig {
case syscall.SIGWINCH:
resizeTty(master)
default:
cmd.Process.Signal(sig)
}
}
}()
}
return namespaces.Exec(container, stdin, stdout, stderr, console, "", dataPath, args, createCommand, startCallback)
}