What does a principal do in public school?

A principal is responsible for making a budget for the school year. Along with that a principal is also expected to give performance reviews to teachers, run professional development seminars, oversee the cafeteria/custodian staff, attend meetings in the school district, administer state testing to students (with students making good marks), ordering supplies, making inventory lists, and anything else the superintendant thinks of. Its a 24/7 job. I have seen principals work as late as 2:00 in the morning