// 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 NewTtyConsole(command *execdriver.Command, pipes *execdriver.Pipes) (*TtyConsole, error) {
ptyMaster, console, err := consolepkg.CreateMasterAndConsole()
if err != nil {
return nil, err
}
tty := &TtyConsole{
MasterPty: ptyMaster,
}
if err := tty.AttachPipes(&command.Cmd, pipes); err != nil {
tty.Close()
return nil, err
}
command.Console = console
return tty, 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)
}