python/semanage: move valid_types initialisations to class constructors

Based on idea from Nicolas Iooss <nicolas.iooss@m4x.org>

Fixes:
$ sudo semanage
Traceback (most recent call last):
  File "/usr/sbin/semanage", line 28, in <module>
    import seobject
  File "/usr/lib/python3.7/site-packages/seobject.py", line 1045, in <module>
    class portRecords(semanageRecords):
  File "/usr/lib/python3.7/site-packages/seobject.py", line 1047, in portRecords
    valid_types = list(list(sepolicy.info(sepolicy.ATTRIBUTE, "port_type"))[0]["types"])
  File "/usr/lib/python3.7/site-packages/sepolicy/__init__.py", line 203, in <genexpr>
    return ({
  File "/usr/lib64/python3.7/site-packages/setools/typeattrquery.py", line 65, in results
    for attr in self.policy.typeattributes():
AttributeError: 'NoneType' object has no attribute 'typeattributes'

SELinuxProject#81

Signed-off-by: Petr Lautrbach <plautrba@redhat.com>

python/semanage/seobject.py

@@ -1043,13 +1043,15 @@ def list(self, heading=1, locallist=0):
 
 
 class portRecords(semanageRecords):
-    try:
-        valid_types = list(list(sepolicy.info(sepolicy.ATTRIBUTE, "port_type"))[0]["types"])
-    except RuntimeError:
-        valid_types = []
+
+    valid_types = []
 
     def __init__(self, args = None):
         semanageRecords.__init__(self, args)
+        try:
+            self.valid_types = list(list(sepolicy.info(sepolicy.ATTRIBUTE, "port_type"))[0]["types"])
+        except RuntimeError:
+            pass
 
     def __genkey(self, port, proto):
         if proto == "tcp":
@@ -1823,14 +1825,16 @@ def list(self, heading=1, locallist=0):
             print(rec)
 
 class nodeRecords(semanageRecords):
-    try:
-        valid_types = list(list(sepolicy.info(sepolicy.ATTRIBUTE, "node_type"))[0]["types"])
-    except RuntimeError:
-        valid_types = []
+
+    valid_types = []
 
     def __init__(self, args = None):
         semanageRecords.__init__(self, args)
         self.protocol = ["ipv4", "ipv6"]
+        try:
+            self.valid_types = list(list(sepolicy.info(sepolicy.ATTRIBUTE, "node_type"))[0]["types"])
+        except RuntimeError:
+            pass
 
     def validate(self, addr, mask, protocol):
         newaddr = addr
@@ -2264,14 +2268,17 @@ def list(self, heading=1, locallist=0):
 
 
 class fcontextRecords(semanageRecords):
-    try:
-        valid_types = list(list(sepolicy.info(sepolicy.ATTRIBUTE, "file_type"))[0]["types"])
-        valid_types += list(list(sepolicy.info(sepolicy.ATTRIBUTE, "device_node"))[0]["types"])
-    except RuntimeError:
-        valid_types = []
+
+    valid_types = []
 
     def __init__(self, args = None):
         semanageRecords.__init__(self, args)
+        try:
+            self.valid_types = list(list(sepolicy.info(sepolicy.ATTRIBUTE, "file_type"))[0]["types"])
+            self.valid_types += list(list(sepolicy.info(sepolicy.ATTRIBUTE, "device_node"))[0]["types"])
+        except RuntimeError:
+            pass
+
         self.equiv = {}
         self.equiv_dist = {}
         self.equal_ind = False