[virt-tools-list] [PATCH 2/7] lxcinstaller: add installer for LXC containers

[Lubomir Rintel]

This adds a LXCInstaller class that will bootstrap the operating system
trees in the LXC containers.

It has an installer phase that runs within the host network and
filesystem tree, but with the uid/gid mapping already set up within the user
namespace (in case it's configured).

This allows fetching the packages from the internet and unpacking the
files with the ownership that makes sense in the installed container.

The actual distribution support will be added in follow-up commits.
---
 virtinst/lxcinstaller.py | 135 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 virtinst/lxcinstaller.py

diff --git a/virtinst/lxcinstaller.py b/virtinst/lxcinstaller.py
new file mode 100644
index 000000000..f5c416d52
--- /dev/null
+++ b/virtinst/lxcinstaller.py
@@ -0,0 +1,135 @@
+#
+# Copyright 2018 Lubomir Rintel <lkundrak at v3.sk>
+#
+# 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 os
+
+from . import urlfetcher
+from . import util
+from .installer import Installer
+from .osxml import OSXML
+
+
+class LXCInstaller(Installer):
+    _has_install_phase = True
+
+    def __init__(self, *args, **kwargs):
+        Installer.__init__(self, *args, **kwargs)
+
+        self._init = None
+        self._initargs = None
+        self._filesystems = None
+        self._interfaces = None
+        self._privnet = None
+        self._target_tree = None
+        self._store = None
+        self._repo_type = None
+        self._repo_url = None
+        self._repo_version = None
+
+    def _get_store(self, guest):
+        if not self._store:
+            scratchdir = util.make_scratchdir(guest.conn, guest.type)
+            meter = util.make_meter(quiet=True)
+            fetcher = urlfetcher.fetcherForURI(self.location, scratchdir, meter)
+            fetcher.prepareLocation()
+            self._store = urlfetcher.getDistroStore(guest, fetcher)
+        return self._store
+
+    ######################################################
+    # Back up and restore settings for the install phase #
+    ######################################################
+
+    def _save_installed_config(self, guest):
+        self._init = guest.os.init
+        self._initargs = guest.os.initargs
+        self._filesystems = guest.get_devices("filesystem")
+        self._interfaces = guest.get_devices("interface")
+        self._privnet = guest.features.privnet
+
+    def _remove_installed_config(self, guest):
+        # The install phase will use a bootstrapper for init
+        for initarg in guest.os.initargs:
+            guest.os.remove_child(initarg)
+        # The bootstrapper will run from the host installation
+        for filesystem in guest.get_devices("filesystem"):
+            guest.remove_device(filesystem)
+        # The bootstrapper will use the host networking
+        guest.features.privnet = False
+        for interface in guest.get_devices("interface"):
+            guest.remove_device(interface)
+
+    def _restore_installed_config(self, guest):
+        guest.features.privnet = self._privnet
+        guest.os.init = self._init
+        for initarg in self._initargs:
+            guest.os.add_child(initarg)
+        for filesystem in self._filesystems:
+            guest.add_device(filesystem)
+        for interface in self._interfaces:
+            guest.add_device(interface)
+
+    ########################################
+    # Run the bootstrap in installer phase #
+    ########################################
+
+    ########################
+    # Private method impls #
+    ########################
+
+    def _get_bootdev(self, isinstall, guest):
+        ignore = isinstall
+        ignore = guest
+        return OSXML.BOOT_DEVICE_HARDDISK
+
+    ##########################
+    # Public installer impls #
+    ##########################
+
+    def detect_distro(self, guest):
+        return self._get_store(guest).get_osdict_info()
+
+    def prepare(self, guest, meter):
+        self._save_installed_config(guest)
+
+        for filesystem in self._filesystems:
+            if filesystem.target == "/":
+                self._target_tree = filesystem.source
+        if not self._target_tree:
+            raise ValueError(_("Need a filesystem to install to."))
+        try:
+            os.mkdir(self._target_tree)
+        except FileExistsError:
+            pass
+
+        uid  = guest.idmap.uid_target
+        if not uid:
+            uid = -1
+        gid  = guest.idmap.gid_target
+        if not gid:
+            gid = -1
+        os.chown(self._target_tree, uid, gid)
+
+        self._repo_type, self._repo_url, self._repo_version = self._get_store(guest).getRepoData()
+
+    def alter_bootconfig(self, guest, isinstall):
+        self._remove_installed_config(guest)
+
+        if isinstall:
+            raise ValueError(_("%s repositories are not supported") % self._repo_type)
+        else:
+            self._restore_installed_config(guest)
-- 
2.14.3