Augmenting IDA UI with your own actions.

Intended audience

Plugin writers, either using the C SDK or IDAPython, who would like to add actions/commands to IDA UI in order to augment its capabilities.

Rationale: before 6.7

APIs galore

Depending on what type of context you were in, various APIs were available to you:

  • Want to add a main menu item?

    add_menu_item(const char *menupath, const char *name, const char *hotkey, int flags, menu_item_callback_t *callback, void *ud);
    del_menu_item(const char *menupath)
    
  • Want to add an action to a list view? (or, as we call them: ‘choosers’)

    add_chooser_command(const char *chooser_caption, const char *cmd_caption, chooser_cb_t *chooser_cb, int menu_index=-1, int icon=-1, int flags=0);
    add_chooser_command(const char *chooser_caption, const char *cmd_caption, chooser_cb_t *chooser_cb, const char *hotkey, int menu_index=-1, int icon=-1, int flags=0);
    

    …or through populating callbacks:

    struct chooser_info_t
    {
        // ...snipped...
        // function is called every time before
        // context menu is shown to fill user_cmds
        prepare_popup_cmds_t *prepare_popup_cmds;
    };
    
  • Want to add/manage the items that show up in the context menu for a custom code viewer you have created? (that does not work for the ‘core’ viewers like ‘IDA View-A’!)

    set_custom_viewer_popup_menu(TCustomControl *custom_viewer, TPopupMenu *menu);
    add_custom_viewer_popup_item(TCustomControl *custom_viewer, const char *title, const char *hotkey, menu_item_callback_t *cb, void *ud);
    
  • Want to add/manage the items that show up in the context menu for a custom graph viewer you have created? (again, doesn’t work with ‘core’ viewers)

    viewer_add_menu_item(graph_viewer_t *gv, const char *title, menu_item_callback_t *callback, void *ud, const char *hotkey, int flags);
    
  • Want to add an item to the Output window’s context menu?

    add_output_popup(char *n, menu_item_callback_t *c, void *u);
    

Drawbacks

Note that not all of those functions take the same set of parameters, or even the same type for seemingly-related ones (e.g., chooser_cb_t *chooser_cb VS menu_item_callback_t *callback)

It is also not possible to specify some attributes of the commands in some cases. E.g.,

  • add_menu_item() doesn’t allow to specify an icon
  • add_output_popup() doesn’t accept a shortcut

And it’s just plain impossible to do some things. E.g.,

  • augment IDA View’s context menu with your own actions
    EDIT: This is incorrect, as the ‘view_popup’ notification could be used for this. However, this is still limited to IDA View-A, and cannot be used for other widgets.
  • remove an item that was previously added to the Output window’s context menu through add_output_popup().
  • in some cases, actions shortcuts would do nothing if the context menu wasn’t currently displayed (i.e., showing the context menu was necessary to enabled the hotkeys)
  • adding custom toolbar buttons was impossible.

These inconsistencies/lack of features were making writing extensions difficult, as the wealth of APIs was somewhat confusing and it was easy to hit the limitations.

In addition, there was no really good way of enabling/disabling your actions, or changing their properties after adding them.

Thus, we decided a refactoring of those APIs was in order.

The new actions API

Borrowing some concepts from Qt itself (upon which IDA’s graphical interface relies) we have decided to redesign the actions API in a hopefully more streamlined manner.

Key aspects

  • An action first needs to be registered. Once registered, it can be triggered using its shortcut (if one was specified), but it doesn’t appear anywhere in the UI just yet.
  • Once registered, it is possible attach/detach that action to/from things:
    • Main menus
    • Toolbars
    • Context menus
  • The same action can be used in multiple places.
  • An action has a “handler”, which is a small structure consisting of two callbacks:
    • an ‘activate’ callback, called when the action was triggered (i.e., user selected a menu item, or entered a shortcut, or pressed a toolbar item, …)
    • an ‘update’ callback, which is responsible for two things:
      • Declaring whether the action is currently enabled, and when it should be queried again for that information.
      • Possibly updating the action’s state (e.g., text, icon, …) (although that’s rarely needed.)

What follows is a series of short examples, using the IDAPython bindings for actions. Note that the IDAPython API is purposely similar to the C SDK API.

Registering an action

    # 1) Create the handler class
    class MyHandler(idaapi.action_handler_t):
        def __init__(self):
            idaapi.action_handler_t.__init__(self)

        # Say hello when invoked.
        def activate(self, ctx):
            print "Hello!"
            return 1

        # This action is always available.
        def update(self, ctx):
            return idaapi.AST_ENABLE_ALWAYS


    # 2) Describe the action
    action_desc = idaapi.action_desc_t(
        'my:action',   # The action name. This acts like an ID and must be unique
        'Say hello!',  # The action text.
        MyHandler(),   # The action handler.
        'Ctrl+H',      # Optional: the action shortcut
        'Says hello',  # Optional: the action tooltip (available in menus/toolbar)
        199)           # Optional: the action icon (shows when in menus/toolbars)

    # 3) Register the action
    idaapi.register_action(action_desc)

From there on, the action is created and, although it has not yet been attached to menus, toolbars or context menus, it can already be invoked by pressing Ctrl+H:

This is slightly more code than before (and in this case, it is explicitely verbose), but regardless of the context/widget in which you want to use that action, it will always be the same API.

Note: In this example, we used icon number 199, which corresponds to a stock icon. It is perfectly possible to define your own icons by using the API function load_custom_icon(). See kernwin.hpp for more information.

Inserting the action into the menu

    idaapi.attach_action_to_menu(
        'Edit/Other/Manual instruction...', # The relative path of where to add the action
        'my:action',                        # The action ID (see above)
        idaapi.SETMENU_APP)                 # We want to append the action after the 'Manual instruction...'

Inserting the action into a toolbar

    idaapi.attach_action_to_toolbar(
        "AnalysisToolBar",  # The toolbar name
        'my:action')        # The action ID

Inserting the action into a widget’s context menu

There are two ways to add actions to a widget’s context menu:

  • Permanently: the action will be there every time the context menu is shown
  • On the fly: you can attach an action as the context menu is being populated, and the action will be displayed in this invocation of the context menu, but not others (unless you attach it again, obviously.)

Attaching an action permanently

To permanently attach an action to a widget’s context menu:

    # Create a widget, or retrieve a pointer to it.
    form = idaapi.get_current_tform()
    idaapi.attach_action_to_popup(form, None, "my:action", None)

Notice that:

  • We used get_current_tform(), to retrieve the widget that currently has the keyboard focus.
  • We passed None as second parameter to attach_action_to_popup(). That means we want to attach the action to that widget permanently.

Pros:

  • Trivial to use.
  • This is what you typically want to use when you create your own widgets

Cons:

  • Only feasible when you can get a reference (i.e., pointer) to the widget.

Attaching an action on-the-fly

To attach an action to a context menu when it is being created, you need to listen to a UI notification, and use the same attach_action_to_popup function:

    class Hooks(idaapi.UI_Hooks):
        def populating_tform_popup(self, form, popup):
            # You can attach here.
            pass

        def finish_populating_tform_popup(self, form, popup):
            # Or here, after the popup is done being populated by its owner.

            # We will attach our action to the context menu
            # for the 'Functions window' widget.
            # The action will be be inserted in a submenu of
            # the context menu, named 'Others'.
            if idaapi.get_tform_type(form) == idaapi.BWN_FUNCS:
                idaapi.attach_action_to_popup(form, popup, "my:action", "Others/")

    hooks = Hooks()
    hooks.hook()

Notice that:

  • This time, the 2nd parameter is not ‘None’. That instructs the function to attach the action for this invocation only.
  • We know that we are currently in the “Functions window”, by checking the type of the current form against BWN_FUNCS. Many other BWN_* values are available; see kernwin.hpp for a list of those!
  • As an alternative, we could check the form’s title, using get_tform_title(form).

Pros:

  • Finer-grained control.
  • You typically want to use this when you cannot easily retrieve a reference (i.e., pointer) to the widget.

Cons:

  • More difficult to use: requires UI hooks.

A word about the update callback

As stated above, the update callback is responsible not only for possibly updating some of the actions properties (See the update_action_* functions in kernwin.hpp), but also for stating whether the action is currently available or not, and when update should be queried again.

Per contract, update should return one of the following values (again, from kernwin.hpp):

    AST_ENABLE_ALWAYS     // enable action and do not call action_handler_t::update() anymore
    AST_ENABLE_FOR_IDB    // enable action for the current idb. Call action_handler_t::update() when a database is opened/closed
    AST_ENABLE_FOR_FORM   // enable action for the current form. Call action_handler_t::update() when a form gets/loses focus
    AST_ENABLE            // enable action - call action_handler_t::update() when anything changes

    AST_DISABLE_ALWAYS    // disable action and do not call action_handler_t::action() anymore
    AST_DISABLE_FOR_IDB   // analog of ::AST_ENABLE_FOR_IDB
    AST_DISABLE_FOR_FORM  // analog of ::AST_ENABLE_FOR_FORM
    AST_DISABLE           // analog of ::AST_ENABLE

Thus, not only does update tell IDA whether the action is available or not, but it also tells IDA the “time span” during which the action will be (un)available.

For example, returning AST_ENABLE_FOR_FORM will tell IDA: “this action is available for the current widget; don’t call update again until the user switches to another widget.”

The AST_* values really represent various levels of “granularity”, where

  • AST_ENABLE_ALWAYS is the coarser level: the action will be available all the time, whatever happens.
  • AST_ENABLE is the finest level: whenever the user moves the cursor, switches to another form, triggers another action, …, update will be called again.

“Dynamic” actions

In most cases, you will want your action to be registered in IDA, and be available through menus, shortcuts, etc…

But there can be “one-shot” situations where you really want to add an action to a context menu only once, and you really don’t want to go through the trouble of registering & deregistering the action.

For those “one-shot” situations, although they are rare, we have created a helper:

    class Hooks(idaapi.UI_Hooks):
        def finish_populating_tform_popup(self, form, popup):
            tft = idaapi.get_tform_type(form)
            if tft == idaapi.BWN_EXPORTS:

                # Define a silly handler.
                class MyHandler(idaapi.action_handler_t):
                    def activate(self, ctx):
                        print "Hello from exports"
                    def update(self, ctx):
                        return idaapi.AST_ENABLE_ALWAYS

                # Note the 'None' as action name (1st parameter).
                # That's because the action will be deleted immediately
                # after the context menu is hidden anyway, so there's
                # really no need giving it a valid ID.
                desc = idaapi.action_desc_t(None, 'My dynamic action', MyHandler())
                idaapi.attach_dynamic_action_to_popup(form, popup, desc, None)

    hooks = Hooks()
    hooks.hook()

The main difference When using attach_dynamic_action_to_popup is that the action will be available only during the time the context menu is displayed. Once the context menu is hidden, the action will be unregistered & destroyed.

Removing action from things

  • detach_action_from_menu
  • detach_action_from_toolbar
  • unregister_action

Older APIs: Backward compatibility

All the previous API is still supported. We have fairly good test coverage of those, and therefore are quite confident the backward compatibility is working.

If your plugin suddenly stops working properly in 6.7, that’s a bug. Should that happen, please let us know about it and we’ll do our best to address it.