root / image_creator / bundle_volume.py @ 5b2ee8c2
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# Copyright 2012 GRNET S.A. All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or
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# without modification, are permitted provided that the following
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# conditions are met:
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#
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# 1. Redistributions of source code must retain the above
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# copyright notice, this list of conditions and the following
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# disclaimer.
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#
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# 2. Redistributions in binary form must reproduce the above
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# copyright notice, this list of conditions and the following
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# disclaimer in the documentation and/or other materials
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# provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
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# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
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# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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#
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# The views and conclusions contained in the software and
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# documentation are those of the authors and should not be
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# interpreted as representing official policies, either expressed
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# or implied, of GRNET S.A.
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import os |
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import re |
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import tempfile |
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import uuid |
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from collections import namedtuple |
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import parted |
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from image_creator.rsync import Rsync |
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from image_creator.util import get_command |
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from image_creator.util import FatalError |
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from image_creator.util import try_fail_repeat |
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from image_creator.util import free_space |
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from image_creator.gpt import GPTPartitionTable |
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findfs = get_command('findfs')
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dd = get_command('dd')
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dmsetup = get_command('dmsetup')
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losetup = get_command('losetup')
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mount = get_command('mount')
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umount = get_command('umount')
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blkid = get_command('blkid')
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tune2fs = get_command('tune2fs')
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MKFS_OPTS = {'ext2': ['-F'], |
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'ext3': ['-F'], |
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'ext4': ['-F'], |
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'reiserfs': ['-ff'], |
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'btrfs': [],
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'minix': [],
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'xfs': ['-f'], |
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'jfs': ['-f'], |
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'ntfs': ['-F'], |
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'msdos': [],
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'vfat': []}
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class BundleVolume(object): |
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"""This class can be used to create an image out of the running system"""
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def __init__(self, out, meta, tmp=None): |
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"""Create an instance of the BundleVolume class."""
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self.out = out
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self.meta = meta
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self.tmp = tmp
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self.out.output('Searching for root device ...', False) |
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root = self._get_root_partition()
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if root.startswith("UUID=") or root.startswith("LABEL="): |
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root = findfs(root).stdout.strip() |
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if not re.match('/dev/[hsv]d[a-z][1-9]*$', root): |
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raise FatalError("Don't know how to handle root device: %s" % root) |
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out.success(root) |
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disk_file = re.split('[0-9]', root)[0] |
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device = parted.Device(disk_file) |
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self.disk = parted.Disk(device)
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def _read_fstable(self, f): |
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"""Use this generator to iterate over the lines of and fstab file"""
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if not os.path.isfile(f): |
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raise FatalError("Unable to open: `%s'. File is missing." % f) |
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FileSystemTableEntry = namedtuple('FileSystemTableEntry',
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'dev mpoint fs opts freq passno')
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with open(f) as table: |
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for line in iter(table): |
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entry = line.split('#')[0].strip().split() |
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if len(entry) != 6: |
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continue
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yield FileSystemTableEntry(*entry)
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def _get_root_partition(self): |
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"""Return the fstab entry accosiated with the root filesystem"""
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for entry in self._read_fstable('/etc/fstab'): |
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if entry.mpoint == '/': |
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return entry.dev
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raise FatalError("Unable to find root device in /etc/fstab") |
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def _is_mpoint(self, path): |
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"""Check if a directory is currently a mount point"""
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for entry in self._read_fstable('/proc/mounts'): |
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if entry.mpoint == path:
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return True |
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return False |
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def _get_mount_options(self, device): |
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"""Return the mount entry associated with a mounted device"""
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for entry in self._read_fstable('/proc/mounts'): |
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if not entry.dev.startswith('/'): |
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continue
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if os.path.realpath(entry.dev) == os.path.realpath(device):
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return entry
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return None |
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def _create_partition_table(self, image): |
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"""Copy the partition table of the host system into the image"""
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# Copy the MBR and the space between the MBR and the first partition.
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# In msdos partition tables Grub Stage 1.5 is located there.
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# In gpt partition tables the Primary GPT Header is there.
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first_sector = self.disk.getPrimaryPartitions()[0].geometry.start |
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dd('if=%s' % self.disk.device.path, 'of=%s' % image, |
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'bs=%d' % self.disk.device.sectorSize, |
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'count=%d' % first_sector, 'conv=notrunc') |
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if self.disk.type == 'gpt': |
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# Copy the Secondary GPT Header
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table = GPTPartitionTable(self.disk.device.path)
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dd('if=%s' % self.disk.device.path, 'of=%s' % image, |
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'bs=%d' % self.disk.device.sectorSize, 'conv=notrunc', |
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'seek=%d' % table.primary.last_usable_lba,
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'skip=%d' % table.primary.last_usable_lba)
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# Create the Extended boot records (EBRs) in the image
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extended = self.disk.getExtendedPartition()
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if not extended: |
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return
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# Extended boot records precede the logical partitions they describe
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logical = self.disk.getLogicalPartitions()
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start = extended.geometry.start |
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for i in range(len(logical)): |
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end = logical[i].geometry.start - 1
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dd('if=%s' % self.disk.device.path, 'of=%s' % image, |
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'count=%d' % (end - start + 1), 'conv=notrunc', |
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'seek=%d' % start, 'skip=%d' % start) |
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start = logical[i].geometry.end + 1
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def _get_partitions(self, disk): |
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"""Returns a list with the partitions of the provided disk"""
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Partition = namedtuple('Partition', 'num start end type fs') |
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partitions = [] |
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for p in disk.partitions: |
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num = p.number |
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start = p.geometry.start |
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end = p.geometry.end |
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ptype = p.type |
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fs = p.fileSystem.type if p.fileSystem is not None else '' |
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partitions.append(Partition(num, start, end, ptype, fs)) |
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return partitions
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def _shrink_partitions(self, image): |
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"""Remove the last partition of the image if it is a swap partition and
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shrink the partition before that. Make sure it can still host all the
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files the corresponding host file system hosts
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"""
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new_end = self.disk.device.length
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image_disk = parted.Disk(parted.Device(image)) |
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is_extended = lambda p: p.type == parted.PARTITION_EXTENDED
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is_logical = lambda p: p.type == parted.PARTITION_LOGICAL
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partitions = self._get_partitions(self.disk) |
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last = partitions[-1]
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if last.fs == 'linux-swap(v1)': |
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MB = 2 ** 20 |
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size = (last.end - last.start + 1) * self.disk.device.sectorSize |
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self.meta['SWAP'] = "%d:%s" % (last.num, (size + MB - 1) // MB) |
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image_disk.deletePartition( |
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image_disk.getPartitionBySector(last.start)) |
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image_disk.commitToDevice() |
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if is_logical(last) and last.num == 5: |
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extended = image_disk.getExtendedPartition() |
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image_disk.deletePartition(extended) |
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image_disk.commitToDevice() |
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partitions.remove(filter(is_extended, partitions)[0]) |
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partitions.remove(last) |
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last = partitions[-1]
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new_end = last.end |
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mount_options = self._get_mount_options(
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self.disk.getPartitionBySector(last.start).path)
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if mount_options is not None: |
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stat = os.statvfs(mount_options.mpoint) |
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# Shrink the last partition. The new size should be the size of the
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# occupied blocks
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blcks = stat.f_blocks - stat.f_bavail |
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new_size = (blcks * stat.f_frsize) // self.disk.device.sectorSize
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# Add 10% just to be on the safe side
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part_end = last.start + (new_size * 11) // 10 |
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# Align to 2048
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part_end = ((part_end + 2047) // 2048) * 2048 |
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# Make sure the partition starts where the old partition started.
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constraint = parted.Constraint(device=image_disk.device) |
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constraint.startRange = parted.Geometry(device=image_disk.device, |
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start=last.start, length=1)
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image_disk.setPartitionGeometry( |
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image_disk.getPartitionBySector(last.start), constraint, |
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start=last.start, end=part_end) |
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image_disk.commitToDevice() |
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# Parted may have changed this for better alignment
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part_end = image_disk.getPartitionBySector(last.start).geometry.end |
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last = last._replace(end=part_end) |
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partitions[-1] = last
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new_end = part_end |
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if last.type == parted.PARTITION_LOGICAL:
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# Fix the extended partition
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image_disk.minimizeExtendedPartition() |
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return (new_end, self._get_partitions(image_disk)) |
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def _map_partition(self, dev, num, start, end): |
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"""Map a partition into a block device using the device mapper"""
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name = os.path.basename(dev) + "_" + uuid.uuid4().hex
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tablefd, table = tempfile.mkstemp() |
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try:
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size = end - start + 1
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os.write(tablefd, "0 %d linear %s %d" % (size, dev, start))
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dmsetup('create', "%sp%d" % (name, num), table) |
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finally:
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os.unlink(table) |
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return "/dev/mapper/%sp%d" % (name, num) |
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def _unmap_partition(self, dev): |
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"""Unmap a previously mapped partition"""
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if not os.path.exists(dev): |
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return
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try_fail_repeat(dmsetup, 'remove', dev.split('/dev/mapper/')[1]) |
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def _mount(self, target, devs): |
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"""Mount a list of filesystems in mountpoints relative to target"""
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devs.sort(key=lambda d: d[1]) |
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for dev, mpoint, options in devs: |
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absmpoint = os.path.abspath(target + mpoint) |
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if not os.path.exists(absmpoint): |
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os.makedirs(absmpoint) |
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if len(options) > 0: |
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mount(dev, absmpoint, '-o', ",".join(options)) |
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else:
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mount(dev, absmpoint) |
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def _umount_all(self, target): |
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"""Unmount all filesystems that are mounted under the directory target
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"""
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mpoints = [] |
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for entry in self._read_fstable('/proc/mounts'): |
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if entry.mpoint.startswith(os.path.abspath(target)):
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mpoints.append(entry.mpoint) |
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mpoints.sort() |
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for mpoint in reversed(mpoints): |
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try_fail_repeat(umount, mpoint) |
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def _to_exclude(self): |
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"""Find which directories to exclude during the image copy. This is
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accompliced by checking which directories serve as mount points for
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virtual file systems
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"""
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excluded = ['/tmp', '/var/tmp'] |
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if self.tmp is not None: |
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excluded.append(self.tmp)
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local_filesystems = MKFS_OPTS.keys() + ['rootfs']
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for entry in self._read_fstable('/proc/mounts'): |
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if entry.fs in local_filesystems: |
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continue
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mpoint = entry.mpoint |
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if mpoint in excluded: |
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continue
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descendants = filter(
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lambda p: p.startswith(mpoint + '/'), excluded) |
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if len(descendants): |
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for d in descendants: |
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excluded.remove(d) |
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excluded.append(mpoint) |
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continue
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dirname = mpoint |
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basename = ''
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found_ancestor = False
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while dirname != '/': |
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(dirname, basename) = os.path.split(dirname) |
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if dirname in excluded: |
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found_ancestor = True
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break
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if not found_ancestor: |
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excluded.append(mpoint) |
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return excluded
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def _replace_uuids(self, target, new_uuid): |
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"""Replace UUID references in various files. This is needed after
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copying system files of the host into a new filesystem
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"""
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files = ['/etc/fstab',
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'/boot/grub/grub.cfg',
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'/boot/grub/menu.lst',
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'/boot/grub/grub.conf']
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orig = {} |
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for p in self.disk.partitions: |
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if p.number in new_uuid.keys(): |
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orig[p.number] = \ |
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blkid('-s', 'UUID', '-o', 'value', p.path).stdout.strip() |
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for f in map(lambda f: target + f, files): |
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if not os.path.exists(f): |
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continue
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with open(f, 'r') as src: |
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lines = src.readlines() |
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with open(f, 'w') as dest: |
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for line in lines: |
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for i, uuid in new_uuid.items(): |
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line = re.sub(orig[i], uuid, line) |
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dest.write(line) |
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def _create_filesystems(self, image, partitions): |
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"""Fill the image with data. Host file systems that are not currently
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mounted are binary copied into the image. For mounted file systems, a
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file system level copy is performed.
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"""
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filesystem = {} |
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orig_dev = {} |
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for p in self.disk.partitions: |
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filesystem[p.number] = self._get_mount_options(p.path)
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orig_dev[p.number] = p.path |
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unmounted = filter(lambda p: filesystem[p.num] is None, partitions) |
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mounted = filter(lambda p: filesystem[p.num] is not None, partitions) |
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# For partitions that are not mounted right now, we can simply dd them
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# into the image.
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for p in unmounted: |
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self.out.output('Cloning partition %d ... ' % p.num, False) |
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dd('if=%s' % self.disk.device.path, 'of=%s' % image, |
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'count=%d' % (p.end - p.start + 1), 'conv=notrunc', |
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'seek=%d' % p.start, 'skip=%d' % p.start) |
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self.out.success("done") |
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|
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loop = str(losetup('-f', '--show', image)).strip() |
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|
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# Recreate mounted file systems
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mapped = {} |
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try:
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for p in mounted: |
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i = p.num |
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mapped[i] = self._map_partition(loop, i, p.start, p.end)
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|
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new_uuid = {} |
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# Create the file systems
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for i, dev in mapped.iteritems(): |
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fs = filesystem[i].fs |
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self.out.output('Creating %s filesystem on partition %d ... ' % |
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(fs, i), False)
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get_command('mkfs.%s' % fs)(*(MKFS_OPTS[fs] + [dev]))
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|
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# For ext[234] enable the default mount options
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if re.match('^ext[234]$', fs): |
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mopts = filter(
|
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lambda p: p.startswith('Default mount options:'), |
415 |
tune2fs('-l', orig_dev[i]).splitlines()
|
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)[0].split(':')[1].strip().split() |
417 |
|
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if not (len(mopts) == 1 and mopts[0] == '(none)'): |
419 |
for opt in mopts: |
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tune2fs('-o', opt, dev)
|
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|
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self.out.success('done') |
423 |
new_uuid[i] = blkid( |
424 |
'-s', 'UUID', '-o', 'value', dev).stdout.strip() |
425 |
|
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target = tempfile.mkdtemp() |
427 |
devs = [] |
428 |
for i in mapped.keys(): |
429 |
fs = filesystem[i].fs |
430 |
mpoint = filesystem[i].mpoint |
431 |
opts = [] |
432 |
for opt in filesystem[i].opts.split(','): |
433 |
if opt in ('acl', 'user_xattr'): |
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opts.append(opt) |
435 |
devs.append((mapped[i], mpoint, opts)) |
436 |
try:
|
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self._mount(target, devs)
|
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|
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excluded = self._to_exclude()
|
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|
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rsync = Rsync(self.out)
|
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|
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for excl in excluded + [image]: |
444 |
rsync.exclude(excl) |
445 |
|
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rsync.archive().hard_links().xattrs().sparse().acls() |
447 |
rsync.run('/', target, 'host', 'temporary image') |
448 |
|
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# Create missing mountpoints. Since they are mountpoints, we
|
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# cannot determine the ownership and the mode of the real
|
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# directory. Make them inherit those properties from their
|
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# parent dir
|
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for excl in excluded: |
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dirname = os.path.dirname(excl) |
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stat = os.stat(dirname) |
456 |
os.mkdir(target + excl) |
457 |
os.chmod(target + excl, stat.st_mode) |
458 |
os.chown(target + excl, stat.st_uid, stat.st_gid) |
459 |
|
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# /tmp and /var/tmp are special cases. We exclude then even if
|
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# they aren't mountpoints. Restore their permissions.
|
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for excl in ('/tmp', '/var/tmp'): |
463 |
if self._is_mpoint(excl): |
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os.chmod(target + excl, 041777)
|
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os.chown(target + excl, 0, 0) |
466 |
else:
|
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stat = os.stat(excl) |
468 |
os.chmod(target + excl, stat.st_mode) |
469 |
os.chown(target + excl, stat.st_uid, stat.st_gid) |
470 |
|
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# We need to replace the old UUID referencies with the new
|
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# ones in grub configuration files and /etc/fstab for file
|
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# systems that have been recreated.
|
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self._replace_uuids(target, new_uuid)
|
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|
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finally:
|
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self._umount_all(target)
|
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os.rmdir(target) |
479 |
finally:
|
480 |
for dev in mapped.values(): |
481 |
self._unmap_partition(dev)
|
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losetup('-d', loop)
|
483 |
|
484 |
def create_image(self, image): |
485 |
"""Given an image filename, this method will create an image out of the
|
486 |
running system.
|
487 |
"""
|
488 |
|
489 |
size = self.disk.device.length * self.disk.device.sectorSize |
490 |
|
491 |
# Create sparse file to host the image
|
492 |
fd = os.open(image, os.O_WRONLY | os.O_CREAT) |
493 |
try:
|
494 |
os.ftruncate(fd, size) |
495 |
finally:
|
496 |
os.close(fd) |
497 |
|
498 |
self._create_partition_table(image)
|
499 |
end_sector, partitions = self._shrink_partitions(image)
|
500 |
|
501 |
if self.disk.type == 'gpt': |
502 |
old_size = size |
503 |
size = (end_sector + 1) * self.disk.device.sectorSize |
504 |
ptable = GPTPartitionTable(image) |
505 |
size = ptable.shrink(size, old_size) |
506 |
else:
|
507 |
# Alighn to 2048
|
508 |
end_sector = ((end_sector + 2047) // 2048) * 2048 |
509 |
size = (end_sector + 1) * self.disk.device.sectorSize |
510 |
|
511 |
# Truncate image to the new size.
|
512 |
fd = os.open(image, os.O_RDWR) |
513 |
try:
|
514 |
os.ftruncate(fd, size) |
515 |
finally:
|
516 |
os.close(fd) |
517 |
|
518 |
# Check if the available space is enough to host the image
|
519 |
dirname = os.path.dirname(image) |
520 |
self.out.output("Examining available space ...", False) |
521 |
if free_space(dirname) <= size:
|
522 |
raise FatalError("Not enough space under %s to host the temporary " |
523 |
"image" % dirname)
|
524 |
self.out.success("sufficient") |
525 |
|
526 |
self._create_filesystems(image, partitions)
|
527 |
|
528 |
return image
|
529 |
|
530 |
# vim: set sta sts=4 shiftwidth=4 sw=4 et ai :
|