# 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 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.already_created = False self.already_cleaned = False # 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", ): raise BlockDeviceSetupException("Label must be 'mbr'") # 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() # 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... if self.already_created: logger.info("Not creating the partitions a second time.") return self.already_created = True # the raw file on disk image_path = self.state['blockdev'][self.base]['image'] # the /dev/loopX device of the parent device_path = self.state['blockdev'][self.base]['device'] logger.info("Creating partition on [%s] [%s]", self.base, image_path) assert self.label == 'mbr' disk_size = self._size_of_block_dev(image_path) with MBR(image_path, 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 device_path[:5] == "/dev/" partition_device_name = "/dev/mapper/%sp%d" % \ (device_path[5:], part_no) self.state['blockdev'][part_name] \ = {'device': partition_device_name} # now all the partitions are created, get device-mapper to # mount them if not os.path.exists("/.dockerenv"): exec_sudo(["kpartx", "-avs", device_path]) # We need to make sure udev finishes creating the device # before continuting, so "udevadm settle". Otherwise later # commands can fail with "file does not exist". # XXX: "-s" (synchronous) to kpartx should avoid this, # but experience shows it does not. exec_sudo(["udevadm", "settle"]) 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", device_path]) exec_sudo(["dmsetup", "--noudevsync", "mknodes"]) return def cleanup(self): # remove the partition mappings made for the parent # block-device by create() above. this is called from the # child PartitionNode umount/delete/cleanup. Thus every # partition calls it, but we only want to do it once and our # gate. if not self.already_cleaned: self.already_cleaned = True exec_sudo(["kpartx", "-d", self.state['blockdev'][self.base]['device']])