#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 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 asyncio
import os
import shutil

import qubes.storage.lvm
import qubes.tests
import qubes.tests.storage_lvm
import qubes.vm.appvm


class StorageTestMixin(object):
    def setUp(self):
        super(StorageTestMixin, self).setUp()
        self.init_default_template()
        self.vm1 = self.app.add_new_vm(qubes.vm.appvm.AppVM,
            name=self.make_vm_name('vm1'),
            label='red')
        self.vm1.create_on_disk()
        self.vm2 = self.app.add_new_vm(qubes.vm.appvm.AppVM,
            name=self.make_vm_name('vm2'),
            label='red')
        self.vm2.create_on_disk()
        self.pool = None
        self.init_pool()
        self.app.save()

    def init_pool(self):
        ''' Initialize storage pool to be tested, store it in self.pool'''
        raise NotImplementedError

    def test_000_volatile(self):
        '''Test if volatile volume is really volatile'''
        return self.loop.run_until_complete(self._test_000_volatile())

    @asyncio.coroutine
    def _test_000_volatile(self):
        size = 32*1024*1024
        volume_config = {
            'pool': self.pool.name,
            'size': size,
            'save_on_stop': False,
            'rw': True,
        }
        testvol = self.vm1.storage.init_volume('testvol', volume_config)
        yield from self.vm1.storage.get_pool(testvol).create(testvol)
        self.app.save()
        yield from (self.vm1.start())

        # volatile image not clean
        yield from (self.vm1.run_for_stdio(
            'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(size),
            user='root'))
        # volatile image not volatile
        yield from (
            self.vm1.run_for_stdio('echo test123 > /dev/xvde', user='root'))
        yield from (self.vm1.shutdown(wait=True))
        yield from (self.vm1.start())
        yield from (self.vm1.run_for_stdio(
            'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(size),
            user='root'))

    def test_001_non_volatile(self):
        '''Test if non-volatile volume is really non-volatile'''
        return self.loop.run_until_complete(self._test_001_non_volatile())

    @asyncio.coroutine
    def _test_001_non_volatile(self):
        size = 32*1024*1024
        volume_config = {
            'pool': self.pool.name,
            'size': size,
            'save_on_stop': True,
            'rw': True,
        }
        testvol = yield from self.vm1.storage.init_volume(
            'testvol', volume_config)
        yield from self.vm1.storage.get_pool(testvol).create(testvol)
        self.app.save()
        yield from self.vm1.start()
        # non-volatile image not clean
        yield from self.vm1.run_for_stdio(
            'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(size),
            user='root')

        yield from self.vm1.run_for_stdio('echo test123 > /dev/xvde',
            user='root')
        yield from self.vm1.shutdown(wait=True)
        yield from self.vm1.start()
        # non-volatile image volatile
        with self.assertRaises(subprocess.CalledProcessError):
            yield from self.vm1.run_for_stdio(
                'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(
                    size),
                user='root')

    def test_002_read_only(self):
        '''Test read-only volume'''
        self.loop.run_until_complete(self._test_002_read_only())

    @asyncio.coroutine
    def _test_002_read_only(self):
        size = 32 * 1024 * 1024
        volume_config = {
            'pool': self.pool.name,
            'size': size,
            'save_on_stop': False,
            'rw': False,
        }
        testvol = self.vm1.storage.init_volume('testvol', volume_config)
        yield from self.vm1.storage.get_pool(testvol).create(testvol)
        self.app.save()
        yield from self.vm1.start()
        # non-volatile image not clean
        yield from self.vm1.run_for_stdio(
            'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(size),
            user='root')
        # Write to read-only volume unexpectedly succeeded
        with self.assertRaises(subprocess.CalledProcessError):
            yield from self.vm1.run_for_stdio('echo test123 > /dev/xvde',
                user='root')
        # read-only volume modified
        yield from self.vm1.run_for_stdio(
            'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(size),
            user='root')

    def test_003_snapshot(self):
        '''Test snapshot volume data propagation'''
        self.loop.run_until_complete(self._test_003_snapshot())

    @asyncio.coroutine
    def _test_003_snapshot(self):
        size = 128 * 1024 * 1024
        volume_config = {
            'pool': self.pool.name,
            'size': size,
            'save_on_stop': True,
            'rw': True,
        }
        testvol = self.vm1.storage.init_volume('testvol', volume_config)
        yield from self.vm1.storage.get_pool(testvol).create(testvol)
        volume_config = {
            'pool': self.pool.name,
            'size': size,
            'snap_on_start': True,
            'source': testvol.vid,
            'rw': True,
        }
        testvol_snap = self.vm2.storage.init_volume('testvol', volume_config)
        yield from self.vm2.storage.get_pool(testvol_snap).create(testvol_snap)
        self.app.save()
        yield from self.vm1.start()
        yield from self.vm2.start()
        # origin image not clean
        yield from self.vm1.run_for_stdio(
            'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(size),
            user='root')

        # snapshot image not clean
        yield from self.vm2.run_for_stdio(
            'head -c {} /dev/zero | diff -q /dev/xvde -'.format(size),
            user='root')

        # Write to read-write volume failed
        yield from self.vm1.run_for_stdio('echo test123 > /dev/xvde && sync',
            user='root')
        # origin changes propagated to snapshot too early
        yield from self.vm2.run_for_stdio(
            'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(size),
            user='root')
        yield from self.vm1.shutdown(wait=True)

        # after origin shutdown there should be still no change

        # origin changes propagated to snapshot too early2
        yield from self.vm2.run_for_stdio(
            'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(size),
            user='root')

        yield from self.vm2.shutdown(wait=True)
        yield from self.vm2.start()

        # only after target VM restart changes should be visible

        # origin changes not visible in snapshot
        with self.assertRaises(subprocess.CalledProcessError):
            yield from self.vm2.run(
                'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(
                    size),
                user='root')

    def test_004_snapshot_non_persistent(self):
        '''Test snapshot volume non-persistence'''
        return self.loop.run_until_complete(
            self._test_004_snapshot_non_persistent())

    @asyncio.coroutine
    def _test_004_snapshot_non_persistent(self):
        size = 128 * 1024 * 1024
        volume_config = {
            'pool': self.pool.name,
            'size': size,
            'save_on_stop': True,
            'rw': True,
        }
        testvol = self.vm1.storage.init_volume('testvol', volume_config)
        yield from self.vm1.storage.get_pool(testvol).create(testvol)
        volume_config = {
            'pool': self.pool.name,
            'size': size,
            'snap_on_start': True,
            'source': testvol.vid,
            'rw': True,
        }
        testvol_snap = self.vm2.storage.init_volume('testvol', volume_config)
        yield from self.vm2.storage.get_pool(testvol_snap).create(testvol_snap)
        self.app.save()
        yield from self.vm2.start()

        # snapshot image not clean
        yield from self.vm2.run_for_stdio(
            'head -c {} /dev/zero | diff -q /dev/xvde -'.format(size),
            user='root')

        # Write to read-write snapshot volume failed
        yield from self.vm2.run_for_stdio('echo test123 > /dev/xvde && sync',
            user='root')
        yield from self.vm2.shutdown(wait=True)
        yield from self.vm2.start()

        # changes on snapshot survived VM restart
        yield from self.vm2.run_for_stdio(
            'head -c {} /dev/zero 2>&1 | diff -q /dev/xvde - 2>&1'.format(size),
            user='root')


class StorageFile(StorageTestMixin, qubes.tests.SystemTestCase):
    def init_pool(self):
        self.dir_path = '/var/tmp/test-pool'
        self.pool = self.app.add_pool(dir_path=self.dir_path,
            name='test-pool', driver='file')
        os.mkdir(os.path.join(self.dir_path, 'appvms', self.vm1.name))
        os.mkdir(os.path.join(self.dir_path, 'appvms', self.vm2.name))

    def tearDown(self):
        self.app.remove_pool('test-pool')
        shutil.rmtree(self.dir_path)
        super(StorageFile, self).tearDown()


@qubes.tests.storage_lvm.skipUnlessLvmPoolExists
class StorageLVM(StorageTestMixin, qubes.tests.SystemTestCase):
    def init_pool(self):
        # check if the default LVM Thin pool qubes_dom0/pool00 exists
        volume_group, thin_pool = \
            qubes.tests.storage_lvm.DEFAULT_LVM_POOL.split('/', 1)
        self.pool = self._find_pool(volume_group, thin_pool)
        if not self.pool:
            self.pool = self.app.add_pool(**qubes.tests.storage_lvm.POOL_CONF)
            self.created_pool = True

    def tearDown(self):
        ''' Remove the default lvm pool if it was created only for this test '''
        if self.created_pool:
            self.app.remove_pool(self.pool.name)
        super(StorageLVM, self).tearDown()

    def _find_pool(self, volume_group, thin_pool):
        ''' Returns the pool matching the specified ``volume_group`` &
            ``thin_pool``, or None.
        '''
        pools = [p for p in self.app.pools
            if issubclass(p.__class__, qubes.storage.lvm.ThinPool)]
        for pool in pools:
            if pool.volume_group == volume_group \
                    and pool.thin_pool == thin_pool:
                return pool
        return None