ext/r3compatibility: create R3.x QubesDB entries

This allows the user to start VM based on "old" system (from R3.x) in
R4.0. For example after restoring from backup, or migration. This also
makes upgrade instruction much easier - no need complex recovery
instruction if one upgrade dom0 before upgrading all the templates.

QubesOS/qubes-issues#1812

qubes/ext/r3compatibility.py

@@ -0,0 +1,105 @@
+#!/usr/bin/python2 -O
+# vim: fileencoding=utf-8
+#
+# The Qubes OS Project, https://www.qubes-os.org/
+#
+# Copyright (C) 2010  Joanna Rutkowska <joanna@invisiblethingslab.com>
+# Copyright (C) 2013-2016  Marek Marczykowski-Górecki
+#                               <marmarek@invisiblethingslab.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+import base64
+import datetime
+import qubes.ext
+import qubes.vm.qubesvm
+import qubes.vm.appvm
+import qubes.vm.templatevm
+import qubes.utils
+
+yum_proxy_ip = '10.137.255.254'
+yum_proxy_port = '8082'
+
+
+class R3Compatibility(qubes.ext.Extension):
+    '''Maintain VM interface compatibility with R3.0 and R3.1.
+    At lease where possible.
+    '''
+    # noinspection PyUnusedLocal
+    @qubes.ext.handler('qdb-created')
+    def on_qdb_created(self, vm, event):
+        """
+        :param vm: VM on which QubesDB entries were just created
+        :type vm: qubes.vm.qubesvm.QubesVM
+        """
+        # /qubes-vm-type: AppVM, NetVM, ProxyVM, TemplateVM
+        if isinstance(vm, qubes.vm.templatevm.TemplateVM):
+            vmtype = 'TemplateVM'
+        elif vm.netvm is not None and vm.provides_network:
+            vmtype = 'ProxyVM'
+        elif vm.netvm is None and vm.provides_network:
+            vmtype = 'NetVM'
+        else:
+            vmtype = 'AppVM'
+        vm.qdb.write('/qubes-vm-type', vmtype)
+
+        # /qubes-vm-updateable
+        vm.qdb.write('/qubes-vm-updateable', str(vm.updateable))
+
+        # /qubes-base-template
+        try:
+            if vm.template:
+                vm.qdb.write('/qubes-base-template', str(vm.template))
+            else:
+                vm.qdb.write('/qubes-base-template', '')
+        except AttributeError:
+            vm.qdb.write('/qubes-base-template', '')
+
+        # /qubes-debug-mode: 0, 1
+        vm.qdb.write('/qubes-debug-mode', str(int(vm.debug)))
+
+        # /qubes-timezone
+        timezone = vm.qdb.read('/timezone')
+        if timezone:
+            vm.qdb.write('/qubes-timezone', timezone)
+
+        # /qubes-vm-persistence
+        persistence = vm.qdb.read('/persistence')
+        if persistence:
+            vm.qdb.write('/qubes-vm-persistence', persistence)
+
+        # /qubes-random-seed
+        # write a new one, to make sure it wouldn't be reused/leaked
+        vm.qdb.write('/qubes-random-seed',
+            base64.b64encode(qubes.utils.urandom(64)))
+
+        # /qubes-keyboard
+        # not needed for now - the old one is still present
+
+        # Networking
+        if vm.provides_network:
+            # '/qubes-netvm-network' value is only checked for being non empty
+            vm.qdb.write('/qubes-netvm-network', vm.gateway)
+            vm.qdb.write('/qubes-netvm-netmask', vm.netmask)
+            vm.qdb.write('/qubes-netvm-gateway', vm.gateway)
+            vm.qdb.write('/qubes-netvm-primary-dns', vm.dns[0])
+            vm.qdb.write('/qubes-netvm-secondary-dns', vm.dns[1])
+
+        if vm.netvm is not None:
+            vm.qdb.write('/qubes-ip', vm.ip)
+            vm.qdb.write('/qubes-netmask', vm.netvm.netmask)
+            vm.qdb.write('/qubes-gateway', vm.netvm.gateway)
+            vm.qdb.write('/qubes-primary-dns', vm.dns[0])
+            vm.qdb.write('/qubes-secondary-dns', vm.dns[1])

rpm_spec/core-dom0.spec

@@ -246,6 +246,7 @@ fi
 %{python_sitelib}/qubes/ext/__init__.py*
 %{python_sitelib}/qubes/ext/gui.py*
 %{python_sitelib}/qubes/ext/qubesmanager.py*
+%{python_sitelib}/qubes/ext/r3compatibility.py*
 
 %dir %{python_sitelib}/qubes/tests
 %{python_sitelib}/qubes/tests/__init__.py*

setup.py

@@ -37,6 +37,7 @@ if __name__ == '__main__':
             'qubes.ext': [
                 'qubes.ext.qubesmanager = qubes.ext.qubesmanager:QubesManager',
                 'qubes.ext.gui = qubes.ext.gui:GUI',
+                'qubes.ext.r3compatibility = qubes.ext.r3compatibility:R3Compatibility',
             ],
         }
     )