func NewTtyConsole(command *execdriver.Command, pipes *execdriver.Pipes) (*TtyConsole, error) {
// lxc is special in that we cannot create the master outside of the container without
// opening the slave because we have nothing to provide to the cmd. We have to open both then do
// the crazy setup on command right now instead of passing the console path to lxc and telling it
// to open up that console. we save a couple of openfiles in the native driver because we can do
// this.
ptyMaster, ptySlave, err := pty.Open()
if err != nil {
return nil, err
}
tty := &TtyConsole{
MasterPty: ptyMaster,
SlavePty: ptySlave,
}
if err := tty.AttachPipes(&command.Cmd, pipes); err != nil {
tty.Close()
return nil, err
}
command.Console = tty.SlavePty.Name()
return tty, nil
}
// callback ensures that the container's state is properly updated after we
// received ack from the execution drivers
func (m *containerMonitor) callback(command *execdriver.Command) {
if command.Tty {
// The callback is called after the process Start()
// so we are in the parent process. In TTY mode, stdin/out/err is the PtySlace
// which we close here.
if c, ok := command.Stdout.(io.Closer); ok {
c.Close()
}
}
m.container.State.SetRunning(command.Pid())
// signal that the process has started
// close channel only if not closed
select {
case <-m.startSignal:
default:
close(m.startSignal)
}
if err := m.container.ToDisk(); err != nil {
log.Debugf("%s", err)
}
}
func (d *driver) generateEnvConfig(c *execdriver.Command) error {
data, err := json.Marshal(c.Env)
if err != nil {
return err
}
p := path.Join(d.root, "containers", c.ID, "config.env")
c.Mounts = append(c.Mounts, execdriver.Mount{
Source: p,
Destination: "/.dockerenv",
Writable: false,
Private: true,
})
return ioutil.WriteFile(p, data, 0600)
}
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
}
func (d *driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (int, error) {
// take the Command and populate the libcontainer.Config from it
container, err := d.createContainer(c)
if err != nil {
return -1, err
}
var term execdriver.Terminal
if c.Tty {
term, err = NewTtyConsole(c, pipes)
} else {
term, err = execdriver.NewStdConsole(c, pipes)
}
if err != nil {
return -1, err
}
c.Terminal = term
d.Lock()
d.activeContainers[c.ID] = &activeContainer{
container: container,
cmd: &c.Cmd,
}
d.Unlock()
var (
dataPath = filepath.Join(d.root, c.ID)
args = append([]string{c.Entrypoint}, c.Arguments...)
)
if err := d.createContainerRoot(c.ID); err != nil {
return -1, err
}
defer d.removeContainerRoot(c.ID)
if err := d.writeContainerFile(container, c.ID); err != nil {
return -1, err
}
return namespaces.Exec(container, c.Stdin, c.Stdout, c.Stderr, c.Console, c.Rootfs, dataPath, args, func(container *libcontainer.Config, console, rootfs, dataPath, init string, child *os.File, args []string) *exec.Cmd {
c.Path = d.initPath
c.Args = append([]string{
DriverName,
"-console", console,
"-pipe", "3",
"-root", filepath.Join(d.root, c.ID),
"--",
}, args...)
// set this to nil so that when we set the clone flags anything else is reset
c.SysProcAttr = &syscall.SysProcAttr{
Cloneflags: uintptr(namespaces.GetNamespaceFlags(container.Namespaces)),
}
c.ExtraFiles = []*os.File{child}
c.Env = container.Env
c.Dir = c.Rootfs
return &c.Cmd
}, func() {
if startCallback != nil {
c.ContainerPid = c.Process.Pid
startCallback(c)
}
})
}
func (d *driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (int, error) {
var (
term execdriver.Terminal
err error
)
if c.Tty {
term, err = NewTtyConsole(c, pipes)
} else {
term, err = execdriver.NewStdConsole(c, pipes)
}
c.Terminal = term
c.Mounts = append(c.Mounts, execdriver.Mount{
Source: d.initPath,
Destination: c.InitPath,
Writable: false,
Private: true,
})
if err := d.generateEnvConfig(c); err != nil {
return -1, err
}
configPath, err := d.generateLXCConfig(c)
if err != nil {
return -1, err
}
params := []string{
"lxc-start",
"-n", c.ID,
"-f", configPath,
"--",
c.InitPath,
}
if c.Network.Interface != nil {
params = append(params,
"-g", c.Network.Interface.Gateway,
"-i", fmt.Sprintf("%s/%d", c.Network.Interface.IPAddress, c.Network.Interface.IPPrefixLen),
)
}
params = append(params,
"-mtu", strconv.Itoa(c.Network.Mtu),
)
if c.User != "" {
params = append(params, "-u", c.User)
}
if c.Privileged {
if d.apparmor {
params[0] = path.Join(d.root, "lxc-start-unconfined")
}
params = append(params, "-privileged")
}
if c.WorkingDir != "" {
params = append(params, "-w", c.WorkingDir)
}
if len(c.CapAdd) > 0 {
params = append(params, fmt.Sprintf("-cap-add=%s", strings.Join(c.CapAdd, ":")))
}
if len(c.CapDrop) > 0 {
params = append(params, fmt.Sprintf("-cap-drop=%s", strings.Join(c.CapDrop, ":")))
}
params = append(params, "--", c.Entrypoint)
params = append(params, c.Arguments...)
if d.sharedRoot {
// lxc-start really needs / to be non-shared, or all kinds of stuff break
// when lxc-start unmount things and those unmounts propagate to the main
// mount namespace.
// What we really want is to clone into a new namespace and then
// mount / MS_REC|MS_SLAVE, but since we can't really clone or fork
// without exec in go we have to do this horrible shell hack...
shellString :=
"mount --make-rslave /; exec " +
utils.ShellQuoteArguments(params)
params = []string{
"unshare", "-m", "--", "/bin/sh", "-c", shellString,
}
}
var (
name = params[0]
arg = params[1:]
)
aname, err := exec.LookPath(name)
if err != nil {
aname = name
}
c.Path = aname
c.Args = append([]string{name}, arg...)
if err := nodes.CreateDeviceNodes(c.Rootfs, c.AutoCreatedDevices); err != nil {
return -1, err
}
if err := c.Start(); err != nil {
return -1, err
}
var (
waitErr error
waitLock = make(chan struct{})
)
go func() {
if err := c.Wait(); err != nil {
if _, ok := err.(*exec.ExitError); !ok { // Do not propagate the error if it's simply a status code != 0
waitErr = err
}
}
close(waitLock)
}()
// Poll lxc for RUNNING status
pid, err := d.waitForStart(c, waitLock)
if err != nil {
if c.Process != nil {
c.Process.Kill()
c.Wait()
}
return -1, err
}
c.ContainerPid = pid
if startCallback != nil {
startCallback(c)
}
<-waitLock
return getExitCode(c), waitErr
}
