src: rewrite polkit ACL generator in Python

As part of a goal to eliminate Perl from libvirt build tools,
rewrite the genpolkit.pl tool in Python.

This was a straight conversion, manually going line-by-line to
change the syntax from Perl to Python. Thus the overall structure
of the file and approach is the same.

Tested-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

scripts/genpolkit.py

@@ -0,0 +1,122 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2012-2019 Red Hat, Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library.  If not, see
+# <http://www.gnu.org/licenses/>.
+#
+
+from __future__ import print_function
+
+import re
+import sys
+
+objects = [
+    "CONNECT", "DOMAIN", "INTERFACE", "NETWORK_PORT",
+    "NETWORK", "NODE_DEVICE", "NWFILTER_BINDING",
+    "NWFILTER", "SECRET", "STORAGE_POOL", "STORAGE_VOL",
+]
+
+objectstr = "|".join(objects)
+
+# Data we're going to be generating looks like this
+#
+# <policyconfig>
+#   <action id="org.libvirt.unix.monitor">
+#     <description>Monitor local virtualized systems</description>
+#     <message>System policy prevents monitoring of
+#              local virtualized systems</message>
+#     <defaults>
+#       <allow_any>yes</allow_any>
+#       <allow_inactive>yes</allow_inactive>
+#       <allow_active>yes</allow_active>
+#     </defaults>
+#   </action>
+#   ...more <action> rules...
+# </policyconfig>
+
+opts = {}
+in_opts = False
+
+perms = {}
+
+aclfile = sys.argv[1]
+with open(aclfile, "r") as fh:
+    for line in fh:
+        if in_opts:
+            if line.find("*/") != -1:
+                in_opts = False
+            else:
+                m = re.search(r'''\*\s*\@(\w+):\s*(.*?)\s*$''', line)
+                if m is not None:
+                    opts[m.group(1)] = m.group(2)
+        elif line.find("**") != -1:
+            in_opts = True
+        else:
+            m = re.search(r'''VIR_ACCESS_PERM_(%s)_((?:\w|_)+),''' %
+                          objectstr, line)
+            if m is not None:
+                obj = m.group(1).lower()
+                perm = m.group(2).lower()
+                if perm == "last":
+                    continue
+
+                obj = obj.replace("_", "-")
+                perm = perm.replace("_", "-")
+
+                if obj not in perms:
+                    perms[obj] = {}
+                perms[obj][perm] = {
+                    "desc": opts.get("desc", None),
+                    "message": opts.get("message", None),
+                    "anonymous": opts.get("anonymous", None),
+                }
+                opts = {}
+
+print('<?xml version="1.0" encoding="UTF-8"?>')
+print('<!DOCTYPE policyconfig PUBLIC ' +
+      '"-//freedesktop//DTD polkit Policy Configuration 1.0//EN"')
+print('    "http://www.freedesktop.org/software/polkit/policyconfig-1.dtd">')
+print('<policyconfig>')
+print('  <vendor>Libvirt Project</vendor>')
+print('  <vendor_url>https://libvirt.org</vendor_url>')
+
+for obj in sorted(perms.keys()):
+    for perm in sorted(perms[obj].keys()):
+        description = perms[obj][perm]["desc"]
+        message = perms[obj][perm]["message"]
+        anonymous = perms[obj][perm]["anonymous"]
+
+        if description is None:
+            raise Exception("missing description for %s.%s" % (obj, perm))
+        if message is None:
+            raise Exception("missing message for %s.%s" % (obj, perm))
+
+        allow_any = "no"
+        if anonymous:
+            allow_any = "yes"
+        allow_inactive = allow_any
+        allow_active = allow_any
+
+        print('  <action id="org.libvirt.api.%s.%s">' % (obj, perm))
+        print('    <description>%s</description>' % description)
+        print('    <message>%s</message>' % message)
+        print('    <defaults>')
+        print('      <allow_any>%s</allow_any>' % allow_any)
+        print('      <allow_inactive>%s</allow_inactive>' % allow_inactive)
+        print('      <allow_active>%s</allow_active>' % allow_active)
+        print('    </defaults>')
+        print('  </action>')
+
+print('</policyconfig>')