// TODO should we support nsenter in a container, running with elevated privs and --pid=host?
func (*NsenterExecHandler) ExecInContainer(client DockerInterface, container *docker.Container, cmd []string, stdin io.Reader, stdout, stderr io.WriteCloser, tty bool) error {
nsenter, err := exec.LookPath("nsenter")
if err != nil {
return fmt.Errorf("exec unavailable - unable to locate nsenter")
}
containerPid := container.State.Pid
// TODO what if the container doesn't have `env`???
args := []string{"-t", fmt.Sprintf("%d", containerPid), "-m", "-i", "-u", "-n", "-p", "--", "env", "-i"}
args = append(args, fmt.Sprintf("HOSTNAME=%s", container.Config.Hostname))
args = append(args, container.Config.Env...)
args = append(args, cmd...)
command := exec.Command(nsenter, args...)
if tty {
p, err := kubecontainer.StartPty(command)
if err != nil {
return err
}
defer p.Close()
// make sure to close the stdout stream
defer stdout.Close()
if stdin != nil {
go io.Copy(p, stdin)
}
if stdout != nil {
go io.Copy(stdout, p)
}
return command.Wait()
} else {
if stdin != nil {
// Use an os.Pipe here as it returns true *os.File objects.
// This way, if you run 'kubectl exec <pod> -i bash' (no tty) and type 'exit',
// the call below to command.Run() can unblock because its Stdin is the read half
// of the pipe.
r, w, err := os.Pipe()
if err != nil {
return err
}
go io.Copy(w, stdin)
command.Stdin = r
}
if stdout != nil {
command.Stdout = stdout
}
if stderr != nil {
command.Stderr = stderr
}
return command.Run()
}
}
// Note: In rkt, the container ID is in the form of "UUID:appName:ImageID", where
// appName is the container name.
func (r *runtime) ExecInContainer(containerID string, cmd []string, stdin io.Reader, stdout, stderr io.WriteCloser, tty bool) error {
glog.V(4).Infof("Rkt execing in container.")
id, err := parseContainerID(containerID)
if err != nil {
return err
}
// TODO(yifan): Use appName instead of imageID.
// see https://github.com/coreos/rkt/pull/640
args := append([]string{}, "enter", "--imageid", id.imageID, id.uuid)
args = append(args, cmd...)
command := r.buildCommand(args...)
if tty {
p, err := kubecontainer.StartPty(command)
if err != nil {
return err
}
defer p.Close()
// make sure to close the stdout stream
defer stdout.Close()
if stdin != nil {
go io.Copy(p, stdin)
}
if stdout != nil {
go io.Copy(stdout, p)
}
return command.Wait()
}
if stdin != nil {
// Use an os.Pipe here as it returns true *os.File objects.
// This way, if you run 'kubectl exec <pod> -i bash' (no tty) and type 'exit',
// the call below to command.Run() can unblock because its Stdin is the read half
// of the pipe.
r, w, err := os.Pipe()
if err != nil {
return err
}
go io.Copy(w, stdin)
command.Stdin = r
}
if stdout != nil {
command.Stdout = stdout
}
if stderr != nil {
command.Stderr = stderr
}
return command.Run()
}