file_ajax_upload in core/modules/file/file.module

Ajax callback: Processes file uploads and deletions.

file_field_instance_settings_form in core/modules/file/file.field.inc

Implements hook_field_instance_settings_form().

file_field_widget_upload_validators in core/modules/file/file.field.inc

Retrieves the upload validators for a file field.

file_get_upload_validators in core/modules/file/file.pages.inc

Retrieves the upload validators for a file.

file_save_upload in core/includes/file.inc

Saves a file upload to a new location.

file_settings_form in core/modules/file/file.admin.inc

Form callback for file settings.

filter_editor_file_upload_settings_form in core/modules/filter/filter.admin.inc

Subform constructor to configure the text editor's file upload settings.

filter_editor_image_upload_settings_form in core/modules/filter/filter.admin.inc

Subform constructor to configure the text editor's image upload settings.

filter_format_editor_image_form in core/modules/filter/filter.pages.inc

Form callback: Display a form for inserting/editing an image.

filter_format_editor_link_form in core/modules/filter/filter.pages.inc

Form callback: Display a form for inserting/editing a link or uploading a file.