search_admin_settings in core/modules/search/search.admin.inc

Menu callback: displays the search module settings page.

search_form in core/modules/search/search.module

Builds a search form.

search_get_default_module_info in core/modules/search/search.module

Returns information about the default search module.

search_is_active in core/modules/search/search.module

Determines access for the ?q=search path.

search_menu in core/modules/search/search.module

Implements hook_menu().

search_view in core/modules/search/search.pages.inc

Menu callback; presents the search form and/or search results.

_search_get_module_names in core/modules/search/search.admin.inc

Helper function to get real module names.