ipaclient_test: Use validate_hostname with constants.MAXHOSTNAMELEN

Run validate_hostname to check for valid host name if constants.MAXHOSTNAMELEN
is defined. The call has not been used in older FreeIPA versions.

roles/ipaclient/library/ipaclient_test.py

@@ -529,6 +529,14 @@ def main():
                 "Invalid hostname, '{}' must not be used.".format(hostname),
                 rval=CLIENT_INSTALL_ERROR)
 
+        if hasattr(constants, "MAXHOSTNAMELEN"):
+            try:
+                validate_hostname(hostname, maxlen=constants.MAXHOSTNAMELEN)
+            except ValueError as e:
+                raise ScriptError(
+                    'invalid hostname: {}'.format(e),
+                    rval=CLIENT_INSTALL_ERROR)
+
         if hasattr(tasks, "is_nosssd_supported"):
             # --no-sssd is not supported any more for rhel-based distros
             if not tasks.is_nosssd_supported() and not options.sssd:

roles/ipaclient/module_utils/ansible_ipa_client.py

@@ -81,6 +81,7 @@ if NUM_VERSION >= 40400:
     except ImportError:
         from ipaclient import ipadiscovery
     from ipalib import api, errors, x509
+    from ipalib import constants
     try:
         from ipalib.install import sysrestore
     except ImportError:
@@ -97,7 +98,8 @@ if NUM_VERSION >= 40400:
     from ipapython import certdb, ipautil
     from ipapython.admintool import ScriptError
     from ipapython.ipautil import CheckedIPAddress
-    from ipalib.util import validate_domain_name, normalize_hostname
+    from ipalib.util import validate_domain_name, normalize_hostname, \
+        validate_hostname
     from ipaplatform import services
     from ipaplatform.paths import paths
     from ipaplatform.tasks import tasks