nss user info question

["Dmitry P. Schegolev" <dmitry at dgap dot mipt dot ru>]

	Good day, people.

I have a question about glibc nss implementation.
I interest in userinfo part of nss, structure passwd, pwd.h.

Some introduction to the problem.
I need a login program that perform kerberos authentication. In common case 
user login name(i.e. dmitry) not equal to kerberos principal name( 
dmitry/People@DGAP.MIPT.RU), and another problem, I need in my domain not all 
users from kerberos can login to the particular host. So I need info about 
allowed accounts from ldap. 

And I need any mechanism to pass to login(and may be any other program, such 
su, mail daemon, etc.)  additional info about user(i.e. kerberos principal to 
authorize to). The best way to do it --- with the help of nss_ldap module. Is 
glibc nss implementation allow to pass additional info about user to caller 
program? Structure passwd, returned by 

struct passwd * getpwnam (const char *name) 

call has fixed number of fields. How I ought to solve my problem the right 
way?

Best regards,
Dmitry.

P. S. If this list is not for these questions, tell me please, where I can ask 
such questions?