change the default terminal directory

Deer jupyter notebook developers:
I have some issues when I using the jupyter notebook.
Here they are:
1.When I "new -> terminal" ,I can't change the default directory.And in my ubuntu OS,
the default directory is '/root',I didn't find any configuration in 'jupyter_notebook_config.py' about changing the default directory of terminal.
2.Any more,If I don't allow other jupyter notebook users accessing any other directory except default terminal working directory,what should I do?

Review jupyter_notebook_config.py and the notebook's "new -> terminal" entry point. The issue contains two separate requests: configuring the terminal's default directory and restricting users to that directory; determine whether each is supported, and define the expected behavior before considering implementation or documentation.

Written by the indexing model from the issue text.