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# Copyright 2016 Andreas Florath (andreas@florath.net)
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
import os
from diskimage_builder.block_device.exception import \
BlockDeviceSetupException
from diskimage_builder.block_device.level1.mbr import MBR
from diskimage_builder.block_device.level1.partition import PartitionNode
from diskimage_builder.block_device.plugin import PluginBase
from diskimage_builder.block_device.utils import exec_sudo
from diskimage_builder.block_device.utils import parse_abs_size_spec
from diskimage_builder.block_device.utils import parse_rel_size_spec
from diskimage_builder.block_device.utils import remove_device
logger = logging.getLogger(__name__)
class Partitioning(PluginBase):
def __init__(self, config, default_config, state):
logger.debug("Creating Partitioning object; config [%s]", config)
super(Partitioning, self).__init__()
# Unlike other PluginBase we are somewhat persistent, as the
# partition nodes call back to us (see create() below). We
# need to keep this reference.
self.state = state
# Because using multiple partitions of one base is done
# within one object, there is the need to store a flag if the
# creation of the partitions was already done.
self.number_of_partitions = 0
# Parameter check
if 'base' not in config:
raise BlockDeviceSetupException("Partitioning config needs 'base'")
self.base = config['base']
if 'partitions' not in config:
raise BlockDeviceSetupException(
"Partitioning config needs 'partitions'")
if 'label' not in config:
raise BlockDeviceSetupException(
"Partitioning config needs 'label'")
self.label = config['label']
if self.label not in ("mbr", "gpt"):
raise BlockDeviceSetupException("Label must be 'mbr' or 'gpt'")
# It is VERY important to get the alignment correct. If this
# is not correct, the disk performance might be very poor.
# Example: In some tests a 'off by one' leads to a write
# performance of 30% compared to a correctly aligned
# partition.
# The problem for DIB is, that it cannot assume that the host
# system uses the same IO sizes as the target system,
# therefore here a fixed approach (as used in all modern
# systems with large disks) is used. The partitions are
# aligned to 1MiB (which are about 2048 times 512 bytes
# blocks)
self.align = 1024 * 1024 # 1MiB as default
if 'align' in config:
self.align = parse_abs_size_spec(config['align'])
self.partitions = []
prev_partition = None
for part_cfg in config['partitions']:
np = PartitionNode(part_cfg, state, self, prev_partition)
self.partitions.append(np)
prev_partition = np
def get_nodes(self):
# return the list of partitions
return self.partitions
def _size_of_block_dev(self, dev):
with open(dev, "r") as fd:
fd.seek(0, 2)
return fd.tell()
def _create_mbr(self):
"""Create partitions with MBR"""
# NOTE(TheJulia): This is funcitonally incompatible with block/sector
# sizing other than 512 bytes.
with MBR(self.image_path, self.disk_size, self.align) as part_impl:
for part_cfg in self.partitions:
part_name = part_cfg.get_name()
part_bootflag = PartitionNode.flag_boot \
in part_cfg.get_flags()
part_primary = PartitionNode.flag_primary \
in part_cfg.get_flags()
part_size = part_cfg.get_size()
part_free = part_impl.free()
part_type = part_cfg.get_type()
logger.debug("Not partitioned space [%d]", part_free)
part_size = parse_rel_size_spec(part_size,
part_free)[1]
part_no \
= part_impl.add_partition(part_primary, part_bootflag,
part_size, part_type)
logger.debug("Create partition [%s] [%d]",
part_name, part_no)
# We're going to mount all partitions with kpartx
# below once we're done. So the device this partition
# will be seen at becomes "/dev/mapper/loop0pX"
assert self.device_path[:5] == "/dev/"
device_name = "%sp%d" % (self.device_path[5:], part_no)
device_path = "/dev/mapper/%s" % device_name
self.state['blockdev'][part_name] \
= {'device': device_path}
part_cfg.add_rollback(remove_device, device_name)
def _create_gpt(self):
"""Create partitions with GPT"""
# Use the loopback via device_path, as using the file means the
# partitioning is exposed to sector sizing of the OS, not of the
# underlying "device" provided by the loopback.
cmd = ['sgdisk', self.device_path]
# This padding gives us a little room for rounding so we don't
# go over the end of the disk
disk_free = self.disk_size - (2048 * 1024)
pnum = 1
for p in self.partitions:
args = {}
args['pnum'] = pnum
args['name'] = '%s' % p.get_name()
args['type'] = '%s' % p.get_type()
# convert from a relative/string size to bytes
size = parse_rel_size_spec(p.get_size(), disk_free)[1]
# We keep track in bytes, but specify things to sgdisk in
# megabytes so it can align on sensible boundaries. And
# create partitions right after previous so no need to
# calculate start/end - just size.
if not size <= disk_free:
logger.error('The requested size of the image is smaller '
'than the block device configuration.')
assert size <= disk_free
args['size'] = size // (1024 * 1024)
new_cmd = ("-n", "{pnum}:0:+{size}M".format(**args),
"-t", "{pnum}:{type}".format(**args),
# Careful with this one, as {name} could have spaces
"-c", "{pnum}:{name}".format(**args))
cmd.extend(new_cmd)
# Fill the state; we mount all partitions with kpartx
# below once we're done. So the device this partition
# will be seen at becomes "/dev/mapper/loop0pX"
assert self.device_path[:5] == "/dev/"
device_name = "%sp%d" % (self.device_path[5:], pnum)
device_path = "/dev/mapper/%s" % device_name
self.state['blockdev'][p.get_name()] \
= {'device': device_path}
disk_free = disk_free - size
pnum = pnum + 1
logger.debug("Partition %s added, %s remaining in disk",
pnum, disk_free)
p.add_rollback(remove_device, device_name)
logger.debug("cmd: %s", ' '.join(cmd))
exec_sudo(cmd)
# not this is NOT a node and this is not called directly! The
# create() calls in the partition nodes this plugin has
# created are calling back into this.
def create(self):
# This is a bit of a hack. Each of the partitions is actually
# in the graph, so for every partition we get a create() call
# as the walk happens. But we only need to create the
# partition table once...
self.number_of_partitions += 1
if self.number_of_partitions > 1:
logger.info("Not creating the partitions a second time.")
return
# the raw file on disk
self.image_path = self.state['blockdev'][self.base]['image']
# the /dev/loopX device of the parent
self.device_path = self.state['blockdev'][self.base]['device']
# underlying size
self.disk_size = self._size_of_block_dev(self.image_path)
logger.info("Creating partition on [%s] [%s]",
self.base, self.image_path)
assert self.label in ('mbr', 'gpt')
if self.label == 'mbr':
self._create_mbr()
elif self.label == 'gpt':
self._create_gpt()
# "saftey sync" to make sure the partitions are written
exec_sudo(["sync"])
# now all the partitions are created, get device-mapper to
# mount them
if not os.path.exists("/.dockerenv"):
exec_sudo(["kpartx", "-uvs", self.device_path])
else:
# If running inside Docker, make our nodes manually,
# because udev will not be working. kpartx cannot run in
# sync mode in docker.
exec_sudo(["kpartx", "-av", self.device_path])
exec_sudo(["dmsetup", "--noudevsync", "mknodes"])
return
def umount(self):
# Remove the partition mappings made for the parent
# block-device by create() above. This is called from the
# child PartitionNode umount. Thus every
# partition calls it, but we only want to do it once when
# we know this is the very last partition
self.number_of_partitions -= 1
if self.number_of_partitions == 0:
exec_sudo(["kpartx", "-d",
self.state['blockdev'][self.base]['device']])
def cleanup(self):
pass
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