Fix ipa-server-install answer cache

Current Answer Cache storing mechanism is not ideal for storing
non-trivial Python types like arrays, custom classes, etc.
RawConfigParser just translates values to string, which
are not correctly decoded when the Answer Cache is parsed and
restored in the installer.

This patch replaces RawConfigParser with Python's standard pickle
module, which is a recommended way for serialization in Python.

https://fedorahosted.org/freeipa/ticket/2054

install/tools/ipa-server-install

@@ -36,7 +36,7 @@ import signal
 import shutil
 import glob
 import traceback
-from ConfigParser import RawConfigParser
+import pickle
 import random
 import tempfile
 import nss.error
@@ -302,45 +302,36 @@ ANSWER_CACHE = "/root/.ipa_cache"
 
 def read_cache(dm_password):
     """
-    Returns a dict of cached answers or None if no cache file exists.
+    Returns a dict of cached answers or empty dict if no cache file exists.
     """
     if not ipautil.file_exists(ANSWER_CACHE):
         return {}
 
     top_dir = tempfile.mkdtemp("ipa")
+    fname = "%s/cache" % top_dir
     try:
-        clearfile = "%s/cache" % top_dir
-        decrypt_file(ANSWER_CACHE, clearfile, dm_password, top_dir)
+        decrypt_file(ANSWER_CACHE, fname, dm_password, top_dir)
     except Exception, e:
         shutil.rmtree(top_dir)
-        raise RuntimeError("Problem decrypting answer cache in %s, check your password." % ANSWER_CACHE)
+        raise Exception("Decryption of answer cache in %s failed, please check your password." % ANSWER_CACHE)
 
-    optdict={}
-    parser = RawConfigParser()
     try:
-        fp = open(clearfile, "r")
-        parser.readfp(fp)
-        optlist = parser.items('options')
-        fp.close()
-
+        with open(fname, 'rb') as f:
+            try:
+                optdict = pickle.load(f)
+            except Exception, e:
+                raise Exception("Parse error in %s: %s" % (ANSWER_CACHE, str(e)))
     except IOError, e:
-        raise RuntimeError("Error reading cache file %s: %s" % (ANSWER_CACHE, str(e)))
+        raise Exception("Read error in %s: %s" % (ANSWER_CACHE, str(e)))
     finally:
         shutil.rmtree(top_dir)
 
-    for opt in optlist:
-        value = opt[1]
-        if value.lower() in ['true', 'false']:
-            value = value.lower() == 'true'
-        if value == 'None':
-            value = None
-        optdict[opt[0]] = value
-
     # These are the only ones that may be overridden
-    if 'external_ca_file' in optdict:
-        del optdict['external_ca_file']
-    if 'external_cert_file' in optdict:
-        del optdict['external_cert_file']
+    for opt in ('external_ca_file', 'external_cert_file'):
+        try:
+            del optdict[opt]
+        except KeyError:
+            pass
 
     return optdict
 
@@ -348,21 +339,14 @@ def write_cache(options):
     """
     Takes a dict as input and writes a cached file of answers
     """
-
-    # convert the options instance into a dict
-    optdict = eval(str(options))
-    parser = RawConfigParser()
     top_dir = tempfile.mkdtemp("ipa")
+    fname = "%s/cache" % top_dir
     try:
-        fp = open("%s/cache" % top_dir, "w")
-        parser.add_section('options')
-        for opt in optdict:
-            parser.set('options', opt, optdict[opt])
-        parser.write(fp)
-        fp.close()
-        ipautil.encrypt_file("%s/cache" % top_dir, ANSWER_CACHE, options.dm_password, top_dir);
+        with open(fname, 'wb') as f:
+            pickle.dump(options, f)
+        ipautil.encrypt_file(fname, ANSWER_CACHE, options['dm_password'], top_dir)
     except IOError, e:
-        raise RuntimeError("Unable to cache command-line options %s" % str(e))
+        raise Exception("Unable to cache command-line options %s" % str(e))
     finally:
         shutil.rmtree(top_dir)
 
@@ -636,7 +620,10 @@ def main():
         dm_password = read_password("Directory Manager", confirm=False)
         if dm_password is None:
             sys.exit("\nDirectory Manager password required")
-        options._update_loose(read_cache(dm_password))
+        try:
+            options._update_loose(read_cache(dm_password))
+        except Exception, e:
+            sys.exit("Cannot process the cache file: %s" % str(e))
 
     if options.external_cert_file:
         try:
@@ -964,7 +951,7 @@ def main():
             options.unattended = True
             options.forwarders = dns_forwarders
             options.reverse_zone = reverse_zone
-            write_cache(options)
+            write_cache(vars(options))
             ca.configure_instance(host_name, dm_password, dm_password,
                                   csr_file="/root/ipa.csr",
                                   subject_base=options.subject)