func (c *migrationFields) send(m proto.Message) error {
	/* gorilla websocket doesn't allow concurrent writes, and
	 * panic()s if it sees them (which is reasonable). If e.g. we
	 * happen to fail, get scheduled, start our write, then get
	 * unscheduled before the write is bit to a new thread which is
	 * receiving an error from the other side (due to our previous
	 * close), we can engage in these concurrent writes, which
	 * casuses the whole daemon to panic.
	 *
	 * Instead, let's lock sends to the controlConn so that we only ever
	 * write one message at the time.
	 */
	c.controlLock.Lock()
	defer c.controlLock.Unlock()
	w, err := c.controlConn.NextWriter(websocket.BinaryMessage)
	if err != nil {
		return err
	}
	defer w.Close()

	data, err := proto.Marshal(m)
	if err != nil {
		return err
	}

	return shared.WriteAll(w, data)
}

func (c *containerLXD) applyPostDeviceConfig() error {
	// applies config that must be delayed until after devices are
	// instantiated, see bug #588 and fix #635

	if lxcConfig, ok := c.config["raw.lxc"]; ok {
		if err := validateRawLxc(lxcConfig); err != nil {
			return err
		}

		f, err := ioutil.TempFile("", "lxd_config_")
		if err != nil {
			return err
		}

		err = shared.WriteAll(f, []byte(lxcConfig))
		f.Close()
		defer os.Remove(f.Name())
		if err != nil {
			return err
		}

		if err := c.c.LoadConfigFile(f.Name()); err != nil {
			return fmt.Errorf("problem applying raw.lxc, perhaps there is a syntax error?")
		}
	}

	return nil
}

func (c *migrationFields) send(m proto.Message) error {
	w, err := c.controlConn.NextWriter(websocket.BinaryMessage)
	if err != nil {
		return err
	}
	defer w.Close()

	data, err := proto.Marshal(m)
	if err != nil {
		return err
	}

	return shared.WriteAll(w, data)
}

func (c *lxdContainer) applyConfig(config map[string]string, fromProfile bool) error {
	var err error
	for k, v := range config {
		switch k {
		case "limits.cpus":
			// TODO - Come up with a way to choose cpus for multiple
			// containers
			var vint int
			count, err := fmt.Sscanf(v, "%d", &vint)
			if err != nil {
				return err
			}
			if count != 1 || vint < 0 || vint > 65000 {
				return fmt.Errorf("Bad cpu limit: %s\n", v)
			}
			cpuset := fmt.Sprintf("0-%d", vint-1)
			err = c.c.SetConfigItem("lxc.cgroup.cpuset.cpus", cpuset)
		case "limits.memory":
			err = c.c.SetConfigItem("lxc.cgroup.memory.limit_in_bytes", v)

		default:
			if strings.HasPrefix(k, "user.") {
				// ignore for now
				err = nil
			}

			/* Things like security.privileged need to be propagated */
			c.config[k] = v
		}
		if err != nil {
			shared.Debugf("error setting %s: %q\n", k, err)
			return err
		}
	}

	if fromProfile {
		return nil
	}

	if lxcConfig, ok := config["raw.lxc"]; ok {
		if err := validateRawLxc(lxcConfig); err != nil {
			return err
		}

		f, err := ioutil.TempFile("", "lxd_config_")
		if err != nil {
			return err
		}

		err = shared.WriteAll(f, []byte(lxcConfig))
		f.Close()
		defer os.Remove(f.Name())
		if err != nil {
			return err
		}

		if err := c.c.LoadConfigFile(f.Name()); err != nil {
			return fmt.Errorf("problem applying raw.lxc, perhaps there is a syntax error?")
		}
	}

	return nil
}