Using mode formats in session.save_path Codeigniter

I'm facing a problem using the session library in Codeigniter. On this page it specifically says

To be more specific, it doesn’t support PHP’s directory level and mode formats used in session.save_path, and it has most of the options hard-coded for safety. Instead, only absolute paths are supported for $config['sess_save_path'].

Now what I want is to create session files with permissions 777. I've set the session_save_path in php.ini to 0;0777;/home/sessions/. This is overwritten by the local value by Codeigniter to /home/sessions. How can I force Codeigniter to create these session files with 777 permissions, as it doesn't support this in the config file.

Please don't mind about the 777 permissions on session files.

from Using mode formats in session.save_path Codeigniter