Forcing yppasswd changes

[mcdonald at AEDC-VAX.AF.MIL]

I am try to force my users to change thier NIS passwords using yppasswd based
on a local NIS map I have set up holding the time of their last change.

After their password is 90 days old I want to force them to change it.  I have
a c-program that does the checking of the age of the password, & I have
it executing from /etc/cshrc & /etc/profile so that it gets executed when
my users log in.

What I want to do in this c-program is:

      if (age > 90) 
         if (fork()==0) 
            execlp ("yppasswd","yppasswd",0);
     
My problem is that this will not necessarily force them to make the change.
(i.e. they can ctrl-c to kill the yppasswd call or they can just type the
new password in wrong & the yppasswd call will abort).

How can I reinvoke yppasswd if it aborts, dies, or is interrupted?


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