implement control protection.

internal/config/session.go

@@ -13,6 +13,7 @@ type Session struct {
 	PrivateMode       bool
 	LockedLogins      bool
 	LockedControls    bool
+	ControlProtection bool
 	ImplicitHosting   bool
 	InactiveCursors   bool
 	MercifulReconnect bool
@@ -45,6 +46,11 @@ func (Session) Init(cmd *cobra.Command) error {
 		return err
 	}
 
+	cmd.PersistentFlags().Bool("session.control_protection", false, "users can gain control only if at least one admin is in the room")
+	if err := viper.BindPFlag("session.control_protection", cmd.PersistentFlags().Lookup("session.control_protection")); err != nil {
+		return err
+	}
+
 	cmd.PersistentFlags().Bool("session.implicit_hosting", true, "allow implicit control switching")
 	if err := viper.BindPFlag("session.implicit_hosting", cmd.PersistentFlags().Lookup("session.implicit_hosting")); err != nil {
 		return err
@@ -95,6 +101,7 @@ func (s *Session) Set() {
 	s.PrivateMode = viper.GetBool("session.private_mode")
 	s.LockedLogins = viper.GetBool("session.locked_logins")
 	s.LockedControls = viper.GetBool("session.locked_controls")
+	s.ControlProtection = viper.GetBool("session.control_protection")
 	s.ImplicitHosting = viper.GetBool("session.implicit_hosting")
 	s.InactiveCursors = viper.GetBool("session.inactive_cursors")
 	s.MercifulReconnect = viper.GetBool("session.merciful_reconnect")

internal/session/manager.go

@@ -21,7 +21,8 @@ func New(config *config.Session) *SessionManagerCtx {
 		settings: types.Settings{
 			PrivateMode:       config.PrivateMode,
 			LockedLogins:      config.LockedLogins,
-			LockedControls:    config.LockedControls,
+			LockedControls:    config.LockedControls || config.ControlProtection,
+			ControlProtection: config.ControlProtection,
 			ImplicitHosting:   config.ImplicitHosting,
 			InactiveCursors:   config.InactiveCursors,
 			MercifulReconnect: config.MercifulReconnect,
@@ -194,6 +195,17 @@ func (manager *SessionManagerCtx) List() []types.Session {
 	return sessions
 }
 
+func (manager *SessionManagerCtx) Range(f func(session types.Session) bool) {
+	manager.sessionsMu.Lock()
+	defer manager.sessionsMu.Unlock()
+
+	for _, session := range manager.sessions {
+		if !f(session) {
+			return
+		}
+	}
+}
+
 // ---
 // host
 // ---
@@ -371,6 +383,23 @@ func (manager *SessionManagerCtx) UpdateSettings(new types.Settings) {
 	manager.settings = new
 	manager.settingsMu.Unlock()
 
+	manager.updateSettings(new, old)
+}
+
+func (manager *SessionManagerCtx) UpdateSettingsFunc(f func(settings *types.Settings) bool) {
+	manager.settingsMu.Lock()
+	new := manager.settings
+	if f(&new) {
+		old := manager.settings
+		manager.settings = new
+		manager.settingsMu.Unlock()
+		manager.updateSettings(new, old)
+		return
+	}
+	manager.settingsMu.Unlock()
+}
+
+func (manager *SessionManagerCtx) updateSettings(new, old types.Settings) {
 	// if private mode changed
 	if old.PrivateMode != new.PrivateMode {
 		// update webrtc paused state for all sessions
@@ -389,6 +418,26 @@ func (manager *SessionManagerCtx) UpdateSettings(new types.Settings) {
 		}
 	}
 
+	// if control protection changed and controls are not locked
+	if old.ControlProtection != new.ControlProtection && new.ControlProtection && !new.LockedControls {
+		// if there is no admin, lock controls
+		hasAdmin := false
+		manager.Range(func(session types.Session) bool {
+			if session.Profile().IsAdmin && session.State().IsConnected {
+				hasAdmin = true
+				return false
+			}
+			return true
+		})
+
+		if !hasAdmin {
+			manager.settingsMu.Lock()
+			manager.settings.LockedControls = true
+			new.LockedControls = true
+			manager.settingsMu.Unlock()
+		}
+	}
+
 	// if contols have been locked
 	if old.LockedControls != new.LockedControls && new.LockedControls {
 		// if the host is not admin, it must release controls

internal/websocket/handler/session.go

@@ -37,6 +37,16 @@ func (h *MessageHandlerCtx) SessionConnected(session types.Session) error {
 		if err := h.systemAdmin(session); err != nil {
 			return err
 		}
+
+		// update settings in atomic way
+		h.sessions.UpdateSettingsFunc(func(settings *types.Settings) bool {
+			// if control protection & locked controls: unlock controls
+			if settings.LockedControls && settings.ControlProtection {
+				settings.LockedControls = false
+				return true // update settings
+			}
+			return false // do not update settings
+		})
 	}
 
 	return h.SessionStateChanged(session)
@@ -49,6 +59,27 @@ func (h *MessageHandlerCtx) SessionDisconnected(session types.Session) error {
 		h.sessions.ClearHost()
 	}
 
+	if session.Profile().IsAdmin {
+		hasAdmin := false
+		h.sessions.Range(func(s types.Session) bool {
+			if s.Profile().IsAdmin && s.ID() != session.ID() && s.State().IsConnected {
+				hasAdmin = true
+				return false
+			}
+			return true
+		})
+
+		// update settings in atomic way
+		h.sessions.UpdateSettingsFunc(func(settings *types.Settings) bool {
+			// if control protection & not locked controls & no admin: lock controls
+			if !settings.LockedControls && settings.ControlProtection && !hasAdmin {
+				settings.LockedControls = true
+				return true // update settings
+			}
+			return false // do not update settings
+		})
+	}
+
 	return h.SessionStateChanged(session)
 }
 

pkg/types/session.go

@@ -43,6 +43,7 @@ type Settings struct {
 	PrivateMode       bool `json:"private_mode"`
 	LockedLogins      bool `json:"locked_logins"`
 	LockedControls    bool `json:"locked_controls"`
+	ControlProtection bool `json:"control_protection"`
 	ImplicitHosting   bool `json:"implicit_hosting"`
 	InactiveCursors   bool `json:"inactive_cursors"`
 	MercifulReconnect bool `json:"merciful_reconnect"`
@@ -80,6 +81,7 @@ type SessionManager interface {
 	Get(id string) (Session, bool)
 	GetByToken(token string) (Session, bool)
 	List() []Session
+	Range(func(Session) bool)
 
 	SetHost(host Session)
 	GetHost() (Session, bool)
@@ -102,6 +104,7 @@ type SessionManager interface {
 	OnSettingsChanged(listener func(new Settings, old Settings))
 
 	UpdateSettings(Settings)
+	UpdateSettingsFunc(f func(settings *Settings) bool)
 	Settings() Settings
 	CookieEnabled() bool