Test the inconsistent locking fix and svc unavail

Test the fix for https://bugzilla.redhat.com/show_bug.cgi?id=586032 .

Also test that krb5kdc can return svc unavailable

src/tests/Makefile.in

@@ -68,6 +68,7 @@ check-pytests:: hist
 	$(RUNPYTEST) $(srcdir)/t_anonpkinit.py $(PYTESTFLAGS)
 	$(RUNPYTEST) $(srcdir)/t_lockout.py $(PYTESTFLAGS)
 	$(RUNPYTEST) $(srcdir)/t_kadm5_hook.py $(PYTESTFLAGS)
+	$(RUNPYTEST) $(srcdir)/t_kdb_locking.py $(PYTESTFLAGS)
 	$(RUNPYTEST) $(srcdir)/t_keyrollover.py $(PYTESTFLAGS)
 	$(RUNPYTEST) $(srcdir)/t_allowed_keysalts.py $(PYTESTFLAGS)
 	$(RUNPYTEST) $(srcdir)/t_renew.py $(PYTESTFLAGS)

src/tests/t_kdb_locking.py

@@ -0,0 +1,39 @@
+#!/usr/bin/python
+
+# This is a regression test for
+# https://bugzilla.redhat.com/show_bug.cgi?id=586032 .
+#
+# We start a KDC, remove the kadm5 lock file, use the KDC, re-create the
+# kadm5 lock file, and use kadmin.local.  The kinit should fail, and the
+# kadmin.local should succeed.
+
+
+import os
+
+from k5test import *
+
+kdc_conf = {
+    'all' : { 'libdefaults' : { 'default_realm' : 'KRBTEST.COM'}}
+}
+
+p = 'foo'
+realm = K5Realm(kdc_conf=kdc_conf, create_user=False)
+realm.addprinc(p, p)
+
+kadm5_lock = os.path.join(realm.testdir, 'master-db.kadm5.lock')
+if not os.path.exists(kadm5_lock):
+    fail('kadm5 lock file not created: ' + kadm5_lock)
+os.unlink(kadm5_lock)
+
+output = realm.kinit(p, p, [], expected_code=1)
+if 'A service is not available' not in output:
+    fail('krb5kdc should have returned service not available error')
+
+f = open(kadm5_lock, 'w')
+f.close()
+
+output = realm.run_kadminl('modprinc -allow_tix ' + p)
+if 'Cannot lock database' in output:
+    fail('krb5kdc still holds a lock on the principal db')
+
+success('KDB locking tests')