added check: password stored in NIS passwd?

examples/passwd-wrapper.scm

@@ -1,5 +1,5 @@
 #!/bin/sh
-exec scsh -lel expect/load.scm -o threads -o expect -o let-opt -e main -s "$0" "$@"
+exec scsh -lel expect/load.scm -lel yp/load.scm -o yp -o threads -o expect -o let-opt -e main -s "$0" "$@"
 !#
 
 ;; TODO:
@@ -165,6 +165,16 @@ Please choose a password with at least 2 character classes.")
 
 ;; *** interface to yppasswd *****************************************
 
+(define (password-stored-in-yp-passwd? user . args)
+  (let-optionals args
+      ((domain (yp-get-default-domain)))
+    (let ((splitter (infix-splitter (rx ":"))))
+      (cond 
+       ((yp-match "passwd.byname" user domain)
+	=> (lambda (entry)
+	     (not (string=? "x" (cadr (splitter entry))))))
+       (else #f)))))
+
 (define yppasswd
   (let ((program "/usr/bin/yppasswd"))
     (case system-type
@@ -192,10 +202,14 @@ Please choose a password with at least 2 character classes.")
 		 )))))
 
 (define (verify-yp-password password)
-  (verify-password yppasswd password))
+  (if (password-stored-in-yp-passwd? (user-login-name))
+      (verify-password yppasswd password)
+      #t))
 
 (define (change-yp-password old-pw new-pw)
-  (change-password yppasswd old-pw new-pw))
+  (if (password-stored-in-yp-passwd? (user-login-name))
+      (change-password yppasswd old-pw new-pw)
+      #t))
 
 ;; *** Kerberos V interface ******************************************