need understanding of getpwnam_alloc

[Dan Wong]

I'm trying to debug a very weird 3.0.25c samba problem where only some
of the windows users are able to logon through winbind authentication
on a windows 2003 DC. The users that can't login shows
NT_STATUS_NO_SUCH_USER because Get_Pwnam_internals didn't find user.

Can someone explain how getpwnam_alloc works?

My assumption is with winbind authentication, winbind retrieves a user
account security data structure(mem_ctx) from the domain controller.
This structure is all the info related to the user (windows ACEs,etc).
 The getpwnam_alloc just checks if this security data structure
belongs to user that is being authenticated.

Please advise if I'm off track.

Thanks,
Dan