Logged in user role

Hi,

I am searching over internet from two days for the below issue

i want to know logged in userrole for the site through webservises

if it is admin page i want to show all options,if it is a teacher i want to hide some options

how can i acheive this through webservises

for example:if logged user is admin for that site(in response i need to get admin)

                     if logged user is teacher for that site(in response i need to get teacher)

How can i achieve this through webservises?

awaiting for reply.............