adtrustinstance: Move attribute definitions from setup to init method

Majority of the attributes set in the setup method can be set in the
__init__ method where they are actually defined (and set to None).

This is true for attributes that hold constant values and for
attributes that have their values derived from api.env dictionary.

Creates a new __setup_default_attributes method, that is called
from within __init__ and setup (in case the passed values for
hostname or domain do not correspond to that what is set in api.env,
doing otherwise could cause unexpected behaviour).

Part of: https://fedorahosted.org/freeipa/ticket/3479

ipaserver/install/adtrustinstance.py

@@ -110,36 +110,72 @@ class ADTRUSTInstance(service.Service):
     FALLBACK_GROUP_NAME = u'Default SMB Group'
 
     def __init__(self, fstore=None):
-        self.fqdn = None
         self.ip_address = None
-        self.realm = None
-        self.domain_name = None
         self.netbios_name = None
         self.reset_netbios_name = None
         self.no_msdcs = None
         self.add_sids = None
         self.smbd_user = None
-        self.suffix = DN()
-        self.ldapi_socket = None
-        self.smb_conf = None
-        self.smb_dn = None
         self.smb_dn_pwd = None
         self.trust_dn = None
         self.smb_dom_dn = None
         self.sub_dict = None
-        self.cifs_principal = None
-        self.cifs_agent = None
-        self.selinux_booleans = None
         self.rid_base = None
         self.secondary_rid_base = None
 
-        service.Service.__init__(self, "smb", service_desc="CIFS", dm_password=None, ldapi=True)
+        self.fqdn = None
+        self.realm = None
+        self.domain_name = None
+
+        service.Service.__init__(self, "smb", service_desc="CIFS",
+                                 dm_password=None, ldapi=True)
 
         if fstore:
             self.fstore = fstore
         else:
             self.fstore = sysrestore.FileStore('/var/lib/ipa/sysrestore')
 
+        self.__setup_default_attributes()
+
+    def __setup_default_attributes(self):
+        """
+        This method setups default attributes that are either constants, or
+        based on api.env attributes, such as realm, hostname or domain name.
+        """
+
+        # Constants
+        self.smb_conf = "/etc/samba/smb.conf"
+        self.samba_keytab = "/etc/samba/samba.keytab"
+        self.selinux_booleans = ["samba_portmapper"]
+        self.cifs_hosts = []
+
+        # Values obtained from API.env
+        self.fqdn = self.fqdn or api.env.host
+        self.realm = self.realm or api.env.realm
+        self.domain_name = self.domain_name or api.env.domain
+
+        self.cifs_principal = "cifs/" + self.fqdn + "@" + self.realm
+        self.suffix = ipautil.realm_to_suffix(self.realm)
+        self.ldapi_socket = "%%2fvar%%2frun%%2fslapd-%s.socket" % \
+                            realm_to_serverid(self.realm)
+
+        # DN definitions
+        self.trust_dn = DN(api.env.container_trusts, self.suffix)
+
+        self.smb_dn = DN(('cn', 'adtrust agents'),
+                         ('cn', 'sysaccounts'),
+                         ('cn', 'etc'),
+                         self.suffix)
+
+        self.smb_dom_dn = DN(('cn', self.domain_name),
+                             api.env.container_cifsdomains,
+                             self.suffix)
+
+        self.cifs_agent = DN(('krbprincipalname', self.cifs_principal.lower()),
+                             api.env.container_service,
+                             self.suffix)
+
+
     def __gen_sid_string(self):
         sub_ids = struct.unpack("<LLL", os.urandom(12))
         return "S-1-5-21-%d-%d-%d" % (sub_ids[0], sub_ids[1], sub_ids[2])
@@ -752,25 +788,9 @@ class ADTRUSTInstance(service.Service):
         self.add_sids = add_sids
         self.enable_compat = enable_compat
         self.smbd_user = smbd_user
-        self.suffix = ipautil.realm_to_suffix(self.realm)
-        self.ldapi_socket = "%%2fvar%%2frun%%2fslapd-%s.socket" % \
-                            realm_to_serverid(self.realm)
 
-        self.smb_conf = "/etc/samba/smb.conf"
-        self.samba_keytab = "/etc/samba/samba.keytab"
-
-        self.smb_dn = DN(('cn', 'adtrust agents'), ('cn', 'sysaccounts'),
-                         ('cn', 'etc'), self.suffix)
-
-        self.trust_dn = DN(api.env.container_trusts, self.suffix)
-        self.smb_dom_dn = DN(('cn', self.domain_name),
-                             api.env.container_cifsdomains, self.suffix)
-        self.cifs_principal = "cifs/" + self.fqdn + "@" + self.realm
-        self.cifs_agent = DN(('krbprincipalname', self.cifs_principal.lower()),
-                             api.env.container_service,
-                             self.suffix)
-        self.selinux_booleans = ["samba_portmapper"]
-        self.cifs_hosts = list()
+        # Setup constants and attributes derived from the values above
+        self.__setup_default_attributes()
 
         self.__setup_sub_dict()