#!/usr/bin/env python3
#
# Test for qcow2 bitmap printed information
#
# Copyright (c) 2019 Virtuozzo International GmbH
#
# 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, see <http://www.gnu.org/licenses/>.
#

import iotests
import json
import struct
from iotests import qemu_img_create, qemu_io, qemu_img_pipe, \
    file_path, img_info_log, log, filter_qemu_io

iotests.verify_image_format(supported_fmts=['qcow2'])

disk = file_path('disk')
chunk = 256 * 1024
bitmap_flag_unknown = 1 << 2
# flag_offset = 5*cluster_size + flag_offset_in_bitmap_directory_entry
flag_offset = 0x5000f


def print_bitmap(extra_args):
    log('qemu-img info dump:\n')
    img_info_log(disk, extra_args=extra_args)
    result = json.loads(qemu_img_pipe('info', '--force-share',
                                      '--output=json', disk))
    if 'bitmaps' in result['format-specific']['data']:
        bitmaps = result['format-specific']['data']['bitmaps']
        log('The same bitmaps in JSON format:')
        log(bitmaps, indent=2)
    else:
        log('No bitmap in JSON format output')


def add_bitmap(bitmap_number, persistent, disabled):
    granularity = 1 << (13 + bitmap_number)
    bitmap_name = 'bitmap-' + str(bitmap_number-1)
    vm = iotests.VM().add_drive(disk)
    vm.launch()
    vm.qmp_log('block-dirty-bitmap-add', node='drive0', name=bitmap_name,
               granularity=granularity, persistent=persistent,
               disabled=disabled)
    vm.shutdown()


def write_to_disk(offset, size):
    write = 'write {} {}'.format(offset, size)
    log(qemu_io('-c', write, disk), filters=[filter_qemu_io])


def toggle_flag(offset):
    with open(disk, "r+b") as f:
        f.seek(offset, 0)
        # Read one byte in a way compatible with Python 2
        flags = struct.unpack("B", f.read(1))
        toggled = flags[0] ^ bitmap_flag_unknown
        f.seek(-1, 1)
        f.write(struct.pack("B", toggled))


qemu_img_create('-f', iotests.imgfmt, disk, '1M')

for num in range(1, 4):
    disabled = False
    if num == 2:
        disabled = True
    log('Test {}'.format(num))
    add_bitmap(num, num > 1, disabled)
    write_to_disk((num-1) * chunk, chunk)
    print_bitmap([])
    log('')

vm = iotests.VM().add_drive(disk)
vm.launch()
num += 1
log('Test {}\nChecking "in-use" flag...'.format(num))
print_bitmap(['--force-share'])
vm.shutdown()

num += 1
log('\nTest {}'.format(num))
qemu_img_create('-f', iotests.imgfmt, disk, '1M')
add_bitmap(1, True, False)
log('Write an unknown bitmap flag \'{}\' into a new QCOW2 image at offset {}'
    .format(hex(bitmap_flag_unknown), flag_offset))
toggle_flag(flag_offset)
img_info_log(disk)
toggle_flag(flag_offset)
log('Unset the unknown bitmap flag \'{}\' in the bitmap directory entry:\n'
    .format(hex(bitmap_flag_unknown)))
img_info_log(disk)
log('Test complete')