Fix version comparison

Use RPM library to compare vendor versions of IPA for redhat platform

https://fedorahosted.org/freeipa/ticket/5535

Reviewed-By: Tomas Babej <tbabej@redhat.com>

freeipa.spec.in

@@ -214,6 +214,7 @@ Requires: python-pyasn1
 Requires: dbus-python
 Requires: python-dns >= 1.11.1
 Requires: python-kdcproxy >= 0.3
+Requires: rpm-python
 
 %description -n python2-ipaserver
 IPA is an integrated solution to provide centrally managed Identity (users,

ipaplatform/redhat/tasks.py

@@ -30,11 +30,13 @@ import stat
 import socket
 import sys
 import base64
+from functools import total_ordering
 
 from subprocess import CalledProcessError
 from nss.error import NSPRError
 from pyasn1.error import PyAsn1Error
 from six.moves import urllib
+import rpm
 
 from ipapython.ipa_log_manager import root_logger, log_mgr
 from ipapython import ipautil
@@ -47,6 +49,35 @@ from ipaplatform.redhat.authconfig import RedHatAuthConfig
 from ipaplatform.base.tasks import BaseTaskNamespace
 
 
+# copied from rpmUtils/miscutils.py
+def stringToVersion(verstring):
+    if verstring in [None, '']:
+        return (None, None, None)
+    i = verstring.find(':')
+    if i != -1:
+        try:
+            epoch = str(long(verstring[:i]))
+        except ValueError:
+            # look, garbage in the epoch field, how fun, kill it
+            epoch = '0' # this is our fallback, deal
+    else:
+        epoch = '0'
+    j = verstring.find('-')
+    if j != -1:
+        if verstring[i + 1:j] == '':
+            version = None
+        else:
+            version = verstring[i + 1:j]
+        release = verstring[j + 1:]
+    else:
+        if verstring[i + 1:] == '':
+            version = None
+        else:
+            version = verstring[i + 1:]
+        release = None
+    return (epoch, version, release)
+
+
 log = log_mgr.get_logger(__name__)
 
 
@@ -66,6 +97,21 @@ def selinux_enabled():
         return False
 
 
+@total_ordering
+class IPAVersion(object):
+
+    def __init__(self, version):
+        self.version_tuple = stringToVersion(version)
+
+    def __eq__(self, other):
+        assert isinstance(other, IPAVersion)
+        return rpm.labelCompare(self.version_tuple, other.version_tuple) == 0
+
+    def __lt__(self, other):
+        assert isinstance(other, IPAVersion)
+        return rpm.labelCompare(self.version_tuple, other.version_tuple) == -1
+
+
 class RedHatTaskNamespace(BaseTaskNamespace):
 
     def restore_context(self, filepath, restorecon=paths.SBIN_RESTORECON):
@@ -426,5 +472,12 @@ class RedHatTaskNamespace(BaseTaskNamespace):
         super(RedHatTaskNamespace, self).create_system_user(name, group,
             homedir, shell, uid, gid, comment, create_homedir)
 
+    def parse_ipa_version(self, version):
+        """
+        :param version: textual version
+        :return: object implementing proper __cmp__ method for version compare
+        """
+        return IPAVersion(version)
+
 
 tasks = RedHatTaskNamespace()