root / image_creator / image.py @ 5756c277
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# -*- coding: utf-8 -*-
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#
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# Copyright 2013 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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from image_creator.util import FatalError |
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from image_creator.gpt import GPTPartitionTable |
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from image_creator.os_type import os_cls |
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import re |
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import guestfs |
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from sendfile import sendfile |
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class Image(object): |
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"""The instances of this class can create images out of block devices."""
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def __init__(self, device, output, **kargs): |
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"""Create a new Image instance"""
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self.device = device
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self.out = output
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self.meta = kargs['meta'] if 'meta' in kargs else {} |
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self.sysprep_params = \
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kargs['sysprep_params'] if 'sysprep_params' in kargs else {} |
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self.progress_bar = None |
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self.guestfs_device = None |
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self.size = 0 |
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self.g = guestfs.GuestFS()
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self.guestfs_enabled = False |
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self.guestfs_version = self.g.version() |
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def check_guestfs_version(self, major, minor, release): |
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"""Checks if the version of the used libguestfs is smaller, equal or
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greater than the one specified by the major, minor and release triplet
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Returns:
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< 0 if the installed version is smaller than the specified one
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= 0 if they are equal
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> 0 if the installed one is greater than the specified one
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"""
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for (a, b) in (self.guestfs_version['major'], major), \ |
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(self.guestfs_version['minor'], minor), \ |
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(self.guestfs_version['release'], release): |
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if a != b:
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return a - b
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return 0 |
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def enable(self): |
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"""Enable a newly created Image instance"""
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self.enable_guestfs()
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self.out.output('Inspecting Operating System ...', False) |
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roots = self.g.inspect_os()
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if len(roots) == 0: |
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raise FatalError("No operating system found") |
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if len(roots) > 1: |
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raise FatalError("Multiple operating systems found." |
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"We only support images with one OS.")
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self.root = roots[0] |
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self.guestfs_device = self.g.part_to_dev(self.root) |
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self.size = self.g.blockdev_getsize64(self.guestfs_device) |
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self.meta['PARTITION_TABLE'] = \ |
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self.g.part_get_parttype(self.guestfs_device) |
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self.ostype = self.g.inspect_get_type(self.root) |
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self.distro = self.g.inspect_get_distro(self.root) |
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self.out.success(
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'found a(n) %s system' %
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self.ostype if self.distro == "unknown" else self.distro) |
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def enable_guestfs(self): |
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"""Enable the guestfs handler"""
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if self.guestfs_enabled: |
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self.out.warn("Guestfs is already enabled") |
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return
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# Before version 1.18.4 the behaviour of kill_subprocess was different
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# and you need to reset the guestfs handler to relaunch a previously
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# shut down qemu backend
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if self.check_guestfs_version(1, 18, 4) < 0: |
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self.g = guestfs.GuestFS()
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self.g.add_drive_opts(self.device, readonly=0, format="raw") |
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# Before version 1.17.14 the recovery process, which is a fork of the
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# original process that called libguestfs, did not close its inherited
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# file descriptors. This can cause problems especially if the parent
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# process has opened pipes. Since the recovery process is an optional
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# feature of libguestfs, it's better to disable it.
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if self.check_guestfs_version(1, 17, 14) >= 0: |
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self.out.output("Enabling recovery proc") |
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self.g.set_recovery_proc(1) |
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else:
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self.g.set_recovery_proc(0) |
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#self.g.set_trace(1)
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#self.g.set_verbose(1)
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self.out.output('Launching helper VM (may take a while) ...', False) |
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# self.progressbar = self.out.Progress(100, "Launching helper VM",
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# "percent")
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# eh = self.g.set_event_callback(self.progress_callback,
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# guestfs.EVENT_PROGRESS)
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self.g.launch()
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self.guestfs_enabled = True |
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# self.g.delete_event_callback(eh)
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# self.progressbar.success('done')
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# self.progressbar = None
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if self.check_guestfs_version(1, 18, 4) < 0: |
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self.g.inspect_os() # some calls need this |
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self.out.success('done') |
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def disable_guestfs(self): |
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"""Disable the guestfs handler"""
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if not self.guestfs_enabled: |
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self.out.warn("Guestfs is already disabled") |
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return
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self.out.output("Shutting down helper VM ...", False) |
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self.g.sync()
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# guestfs_shutdown which is the prefered way to shutdown the backend
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# process was introduced in version 1.19.16
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if self.check_guestfs_version(1, 19, 16) >= 0: |
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self.g.shutdown()
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else:
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self.g.kill_subprocess()
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self.guestfs_enabled = False |
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self.out.success('done') |
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def _get_os(self): |
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"""Return an OS class instance for this image"""
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if hasattr(self, "_os"): |
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return self._os |
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if not self.guestfs_enabled: |
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self.enable()
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cls = os_cls(self.distro, self.ostype) |
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self._os = cls(self, sysprep_params=self.sysprep_params) |
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self._os.collect_metadata()
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return self._os |
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os = property(_get_os)
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def destroy(self): |
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"""Destroy this Image instance."""
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# In new guestfs versions, there is a handy shutdown method for this
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try:
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if self.guestfs_enabled: |
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self.g.umount_all()
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self.g.sync()
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finally:
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# Close the guestfs handler if open
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self.g.close()
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# def progress_callback(self, ev, eh, buf, array):
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# position = array[2]
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# total = array[3]
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#
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# self.progressbar.goto((position * 100) // total)
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def _last_partition(self): |
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"""Return the last partition of the image disk"""
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if self.meta['PARTITION_TABLE'] not in 'msdos' 'gpt': |
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msg = "Unsupported partition table: %s. Only msdos and gpt " \
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"partition tables are supported" % self.meta['PARTITION_TABLE'] |
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raise FatalError(msg)
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is_extended = lambda p: \
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self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) \ |
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in (0x5, 0xf) |
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is_logical = lambda p: \
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self.meta['PARTITION_TABLE'] == 'msdos' and p['part_num'] > 4 |
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partitions = self.g.part_list(self.guestfs_device) |
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last_partition = partitions[-1]
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if is_logical(last_partition):
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# The disk contains extended and logical partitions....
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extended = filter(is_extended, partitions)[0] |
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last_primary = [p for p in partitions if p['part_num'] <= 4][-1] |
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# check if extended is the last primary partition
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if last_primary['part_num'] > extended['part_num']: |
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last_partition = last_primary |
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return last_partition
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def shrink(self): |
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"""Shrink the image.
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This is accomplished by shrinking the last file system of the
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image and then updating the partition table. The new disk size
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(in bytes) is returned.
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ATTENTION: make sure unmount is called before shrink
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"""
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get_fstype = lambda p: \
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self.g.vfs_type("%s%d" % (self.guestfs_device, p['part_num'])) |
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is_logical = lambda p: \
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self.meta['PARTITION_TABLE'] == 'msdos' and p['part_num'] > 4 |
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is_extended = lambda p: \
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self.meta['PARTITION_TABLE'] == 'msdos' and \ |
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self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) \ |
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in (0x5, 0xf) |
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part_add = lambda ptype, start, stop: \
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self.g.part_add(self.guestfs_device, ptype, start, stop) |
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part_del = lambda p: self.g.part_del(self.guestfs_device, p) |
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part_get_id = lambda p: self.g.part_get_mbr_id(self.guestfs_device, p) |
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part_set_id = lambda p, id: \ |
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self.g.part_set_mbr_id(self.guestfs_device, p, id) |
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part_get_bootable = lambda p: \
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self.g.part_get_bootable(self.guestfs_device, p) |
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part_set_bootable = lambda p, bootable: \
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self.g.part_set_bootable(self.guestfs_device, p, bootable) |
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MB = 2 ** 20 |
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self.out.output("Shrinking image (this may take a while) ...", False) |
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sector_size = self.g.blockdev_getss(self.guestfs_device) |
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last_part = None
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fstype = None
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while True: |
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last_part = self._last_partition()
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fstype = get_fstype(last_part) |
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if fstype == 'swap': |
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self.meta['SWAP'] = "%d:%s" % \ |
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(last_part['part_num'],
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(last_part['part_size'] + MB - 1) // MB) |
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part_del(last_part['part_num'])
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continue
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elif is_extended(last_part):
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part_del(last_part['part_num'])
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continue
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# Most disk manipulation programs leave 2048 sectors after the last
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# partition
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new_size = last_part['part_end'] + 1 + 2048 * sector_size |
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self.size = min(self.size, new_size) |
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break
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if not re.match("ext[234]", fstype): |
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self.out.warn("Don't know how to shrink %s partitions." % fstype) |
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return self.size |
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part_dev = "%s%d" % (self.guestfs_device, last_part['part_num']) |
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self.g.e2fsck_f(part_dev)
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self.g.resize2fs_M(part_dev)
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out = self.g.tune2fs_l(part_dev)
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block_size = int(filter(lambda x: x[0] == 'Block size', out)[0][1]) |
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block_cnt = int(filter(lambda x: x[0] == 'Block count', out)[0][1]) |
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start = last_part['part_start'] / sector_size
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end = start + (block_size * block_cnt) / sector_size - 1
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if is_logical(last_part):
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partitions = self.g.part_list(self.guestfs_device) |
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logical = [] # logical partitions
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for partition in partitions: |
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if partition['part_num'] < 4: |
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continue
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logical.append({ |
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'num': partition['part_num'], |
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'start': partition['part_start'] / sector_size, |
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'end': partition['part_end'] / sector_size, |
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'id': part_get_id(partition['part_num']), |
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'bootable': part_get_bootable(partition['part_num']) |
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}) |
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logical[-1]['end'] = end # new end after resize |
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# Recreate the extended partition
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extended = filter(is_extended, partitions)[0] |
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part_del(extended['part_num'])
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part_add('e', extended['part_start'] / sector_size, end) |
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# Create all the logical partitions back
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for l in logical: |
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part_add('l', l['start'], l['end']) |
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part_set_id(l['num'], l['id']) |
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part_set_bootable(l['num'], l['bootable']) |
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else:
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# Recreate the last partition
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if self.meta['PARTITION_TABLE'] == 'msdos': |
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last_part['id'] = part_get_id(last_part['part_num']) |
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last_part['bootable'] = part_get_bootable(last_part['part_num']) |
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part_del(last_part['part_num'])
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part_add('p', start, end)
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part_set_bootable(last_part['part_num'], last_part['bootable']) |
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if self.meta['PARTITION_TABLE'] == 'msdos': |
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part_set_id(last_part['part_num'], last_part['id']) |
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new_size = (end + 1) * sector_size
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assert (new_size <= self.size) |
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if self.meta['PARTITION_TABLE'] == 'gpt': |
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ptable = GPTPartitionTable(self.device)
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self.size = ptable.shrink(new_size, self.size) |
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else:
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self.size = min(new_size + 2048 * sector_size, self.size) |
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self.out.success("new size is %dMB" % ((self.size + MB - 1) // MB)) |
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return self.size |
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def dump(self, outfile): |
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"""Dumps the content of the image into a file.
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This method will only dump the actual payload, found by reading the
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partition table. Empty space in the end of the device will be ignored.
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"""
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MB = 2 ** 20 |
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blocksize = 4 * MB # 4MB |
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size = self.size
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progr_size = (size + MB - 1) // MB # in MB |
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progressbar = self.out.Progress(progr_size, "Dumping image file", 'mb') |
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with open(self.device, 'r') as src: |
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with open(outfile, "w") as dst: |
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left = size |
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offset = 0
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progressbar.next() |
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while left > 0: |
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length = min(left, blocksize)
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sent = sendfile(dst.fileno(), src.fileno(), offset, length) |
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# Workaround for python-sendfile API change. In
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# python-sendfile 1.2.x (py-sendfile) the returning value
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# of sendfile is a tuple, where in version 2.x (pysendfile)
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# it is just a sigle integer.
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if isinstance(sent, tuple): |
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sent = sent[1]
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offset += sent |
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left -= sent |
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progressbar.goto((size - left) // MB) |
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progressbar.success('image file %s was successfully created' % outfile)
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# vim: set sta sts=4 shiftwidth=4 sw=4 et ai :
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