func execAction(context *cli.Context) {
var nspid, exitCode int
container, err := loadContainer()
if err != nil {
log.Fatal(err)
}
if nspid, err = readPid(); err != nil && !os.IsNotExist(err) {
log.Fatalf("unable to read pid: %s", err)
}
if nspid > 0 {
err = namespaces.ExecIn(container, nspid, []string(context.Args()))
} else {
term := namespaces.NewTerminal(os.Stdin, os.Stdout, os.Stderr, container.Tty)
exitCode, err = startContainer(container, term, dataPath, []string(context.Args()))
}
if err != nil {
log.Fatalf("failed to exec: %s", err)
}
os.Exit(exitCode)
}
func execAction(context *cli.Context) {
var exitCode int
container, err := loadContainer()
if err != nil {
log.Fatal(err)
}
state, err := libcontainer.GetState(dataPath)
if err != nil && !os.IsNotExist(err) {
log.Fatalf("unable to read state.json: %s", err)
}
if state != nil {
err = namespaces.ExecIn(container, state, []string(context.Args()))
} else {
term := namespaces.NewTerminal(os.Stdin, os.Stdout, os.Stderr, container.Tty)
exitCode, err = startContainer(container, term, dataPath, []string(context.Args()))
}
if err != nil {
log.Fatalf("failed to exec: %s", err)
}
os.Exit(exitCode)
}
// TODO(vishh): Add support for running in priviledged mode and running as a different user.
func (d *driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (int, error) {
active := d.activeContainers[c.ID]
if active == nil {
return -1, fmt.Errorf("No active container exists with ID %s", c.ID)
}
state, err := libcontainer.GetState(filepath.Join(d.root, c.ID))
if err != nil {
return -1, fmt.Errorf("State unavailable for container with ID %s. The container may have been cleaned up already. Error: %s", c.ID, err)
}
var term execdriver.Terminal
if processConfig.Tty {
term, err = NewTtyConsole(processConfig, pipes)
} else {
term, err = execdriver.NewStdConsole(processConfig, pipes)
}
processConfig.Terminal = term
args := append([]string{processConfig.Entrypoint}, processConfig.Arguments...)
return namespaces.ExecIn(active.container, state, args, os.Args[0], "exec", processConfig.Stdin, processConfig.Stdout, processConfig.Stderr, processConfig.Console,
func(cmd *exec.Cmd) {
if startCallback != nil {
startCallback(&c.ProcessConfig, cmd.Process.Pid)
}
})
}
// 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 TestExecInRlimit(t *testing.T) {
if testing.Short() {
return
}
rootfs, err := newRootFs()
if err != nil {
t.Fatal(err)
}
defer remove(rootfs)
config := newTemplateConfig(rootfs)
if err := writeConfig(config); err != nil {
t.Fatalf("failed to write config %s", err)
}
containerCmd, statePath, containerErr := startLongRunningContainer(config)
defer func() {
// kill the container
if containerCmd.Process != nil {
containerCmd.Process.Kill()
}
if err := <-containerErr; err != nil {
t.Fatal(err)
}
}()
// start the exec process
state, err := libcontainer.GetState(statePath)
if err != nil {
t.Fatalf("failed to get state %s", err)
}
buffers := newStdBuffers()
execErr := make(chan error, 1)
go func() {
_, err := namespaces.ExecIn(config, state, []string{"/bin/sh", "-c", "ulimit -n"},
os.Args[0], "exec", buffers.Stdin, buffers.Stdout, buffers.Stderr,
"", nil)
execErr <- err
}()
if err := <-execErr; err != nil {
t.Fatalf("exec finished with error %s", err)
}
out := buffers.Stdout.String()
if limit := strings.TrimSpace(out); limit != "1024" {
t.Fatalf("expected rlimit to be 1024, got %s", limit)
}
}
func TestExecIn(t *testing.T) {
if testing.Short() {
return
}
rootfs, err := newRootFs()
if err != nil {
t.Fatal(err)
}
defer remove(rootfs)
config := newTemplateConfig(rootfs)
if err := writeConfig(config); err != nil {
t.Fatalf("failed to write config %s", err)
}
containerCmd, statePath, containerErr := startLongRunningContainer(config)
defer func() {
// kill the container
if containerCmd.Process != nil {
containerCmd.Process.Kill()
}
if err := <-containerErr; err != nil {
t.Fatal(err)
}
}()
// start the exec process
state, err := libcontainer.GetState(statePath)
if err != nil {
t.Fatalf("failed to get state %s", err)
}
buffers := newStdBuffers()
execErr := make(chan error, 1)
go func() {
_, err := namespaces.ExecIn(config, state, []string{"ps"},
os.Args[0], "exec", buffers.Stdin, buffers.Stdout, buffers.Stderr,
"", nil)
execErr <- err
}()
if err := <-execErr; err != nil {
t.Fatalf("exec finished with error %s", err)
}
out := buffers.Stdout.String()
if !strings.Contains(out, "sleep 10") || !strings.Contains(out, "ps") {
t.Fatalf("unexpected running process, output %q", out)
}
}
