X-Git-Url: https://code.grnet.gr/git/snf-image-creator/blobdiff_plain/e7c01d1ea5b31a3950f95c8758b99750d0d85f38..29fd973e0da4b1bf61f76a7809b67b18ef9db195:/image_creator/disk.py diff --git a/image_creator/disk.py b/image_creator/disk.py index 6d0ad1f..b4311f8 100644 --- a/image_creator/disk.py +++ b/image_creator/disk.py @@ -1,41 +1,56 @@ -#!/usr/bin/env python +# Copyright 2012 GRNET S.A. All rights reserved. +# +# Redistribution and use in source and binary forms, with or +# without modification, are permitted provided that the following +# conditions are met: +# +# 1. Redistributions of source code must retain the above +# copyright notice, this list of conditions and the following +# disclaimer. +# +# 2. Redistributions in binary form must reproduce the above +# copyright notice, this list of conditions and the following +# disclaimer in the documentation and/or other materials +# provided with the distribution. +# +# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS +# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR +# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF +# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED +# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +# POSSIBILITY OF SUCH DAMAGE. +# +# The views and conclusions contained in the software and +# documentation are those of the authors and should not be +# interpreted as representing official policies, either expressed +# or implied, of GRNET S.A. + +from image_creator.util import get_command +from image_creator.util import try_fail_repeat +from image_creator.util import free_space +from image_creator.util import FatalError +from image_creator.bundle_volume import BundleVolume +from image_creator.image import Image -import losetup import stat import os import tempfile import uuid -import re -import sys -import guestfs +import shutil -import pbs -from pbs import dd -from clint.textui import progress +dd = get_command('dd') +dmsetup = get_command('dmsetup') +losetup = get_command('losetup') +blockdev = get_command('blockdev') -class DiskError(Exception): - pass - - -def find_sbin_command(command, exception): - search_paths = ['/usr/local/sbin', '/usr/sbin', '/sbin'] - for fullpath in map(lambda x: "%s/%s" % (x, command), search_paths): - if os.path.exists(fullpath) and os.access(fullpath, os.X_OK): - return pbs.Command(fullpath) - continue - raise exception - - -try: - from pbs import dmsetup -except pbs.CommandNotFound as e: - dmsetup = find_sbin_command('dmsetup', e) - -try: - from pbs import blockdev -except pbs.CommandNotFound as e: - blockdev = find_sbin_command('blockdev', e) +TMP_CANDIDATES = ['/var/tmp', os.path.expanduser('~'), '/mnt'] class Disk(object): @@ -46,216 +61,137 @@ class Disk(object): the Linux kernel. """ - def __init__(self, source): + def __init__(self, source, output, tmp=None): """Create a new Disk instance out of a source media. The source - media can be an image file, a block device or a directory.""" + media can be an image file, a block device or a directory. + """ self._cleanup_jobs = [] - self._devices = [] + self._images = [] self.source = source + self.out = output + self.meta = {} + self.tmp = tempfile.mkdtemp(prefix='.snf_image_creator.', + dir=self._get_tmp_dir(tmp)) + + self._add_cleanup(shutil.rmtree, self.tmp) + + def _get_tmp_dir(self, default=None): + """Check tmp directory candidates and return the one with the most + available space. + """ + if default is not None: + return default + + space = map(free_space, TMP_CANDIDATES) + + max_idx = 0 + max_val = space[0] + for i, val in zip(range(len(space)), space): + if val > max_val: + max_val = val + max_idx = i + + # Return the candidate path with more available space + return TMP_CANDIDATES[max_idx] def _add_cleanup(self, job, *args): + """Add a new job in the cleanup list""" self._cleanup_jobs.append((job, args)) def _losetup(self, fname): - loop = losetup.find_unused_loop_device() - loop.mount(fname) - self._add_cleanup(loop.unmount) - return loop.device + """Setup a loop device and add it to the cleanup list. The loop device + will be detached when cleanup is called. + """ + loop = losetup('-f', '--show', fname) + loop = loop.strip() # remove the new-line char + self._add_cleanup(try_fail_repeat, losetup, '-d', loop) + return loop def _dir_to_disk(self): - raise NotImplementedError + """Create a disk out of a directory""" + if self.source == '/': + bundle = BundleVolume(self.out, self.meta) + image = '%s/%s.diskdump' % (self.tmp, uuid.uuid4().hex) + + def check_unlink(path): + if os.path.exists(path): + os.unlink(path) + + self._add_cleanup(check_unlink, image) + bundle.create_image(image) + return self._losetup(image) + raise FatalError("Using a directory as media source is supported") def cleanup(self): """Cleanup internal data. This needs to be called before the program ends. """ - while len(self._devices): - device = self._devices.pop() - device.destroy() - - while len(self._cleanup_jobs): - job, args = self._cleanup_jobs.pop() - job(*args) - - def get_device(self): - """Returns a newly created DiskDevice instance. - - This instance is a snapshot of the original source media of - the Disk instance. + try: + while len(self._images): + image = self._images.pop() + image.destroy() + finally: + # Make sure those are executed even if one of the device.destroy + # methods throws exeptions. + while len(self._cleanup_jobs): + job, args = self._cleanup_jobs.pop() + job(*args) + + def snapshot(self): + """Creates a snapshot of the original source media of the Disk + instance. """ + + self.out.output("Examining source media `%s' ..." % self.source, False) sourcedev = self.source mode = os.stat(self.source).st_mode if stat.S_ISDIR(mode): - return self._losetup(self._dir_to_disk()) + self.out.success('looks like a directory') + return self._dir_to_disk() elif stat.S_ISREG(mode): + self.out.success('looks like an image file') sourcedev = self._losetup(self.source) elif not stat.S_ISBLK(mode): - raise ValueError("Value for self.source is invalid") + raise FatalError("Invalid media source. Only block devices, " + "regular files and directories are supported.") + else: + self.out.success('looks like a block device') # Take a snapshot and return it to the user - size = blockdev('--getsize', sourcedev) - cowfd, cow = tempfile.mkstemp() + self.out.output("Snapshotting media source...", False) + size = blockdev('--getsz', sourcedev) + cowfd, cow = tempfile.mkstemp(dir=self.tmp) + os.close(cowfd) self._add_cleanup(os.unlink, cow) - # Create 1G cow sparse file - dd('if=/dev/null', 'of=%s' % cow, 'bs=1k', 'seek=%d' % (1024 * 1024)) + # Create cow sparse file + dd('if=/dev/null', 'of=%s' % cow, 'bs=512', 'seek=%d' % int(size)) cowdev = self._losetup(cow) snapshot = uuid.uuid4().hex tablefd, table = tempfile.mkstemp() try: - os.write(tablefd, "0 %d snapshot %s %s n 8" % \ - (int(size), sourcedev, cowdev)) + os.write(tablefd, "0 %d snapshot %s %s n 8" % + (int(size), sourcedev, cowdev)) dmsetup('create', snapshot, table) - self._add_cleanup(dmsetup, 'remove', snapshot) + self._add_cleanup(try_fail_repeat, dmsetup, 'remove', snapshot) + finally: os.unlink(table) + self.out.success('done') + return "/dev/mapper/%s" % snapshot - new_device = DiskDevice("/dev/mapper/%s" % snapshot) - self._devices.append(new_device) - return new_device - - def destroy_device(self, device): - """Destroys a DiskDevice instance previously created by - get_device method. - """ - self._devices.remove(device) - device.destroy() - - -def progress_generator(total): - position = 0; - for i in progress.bar(range(total)): - if i < position: - continue - position = yield - yield #suppress the StopIteration exception + def get_image(self, media): + """Returns a newly created Image instance.""" + image = Image(media, self.out) + self._images.append(image) + image.enable() + return image -class DiskDevice(object): - """This class represents a block device hosting an Operating System - as created by the device-mapper. - """ - - def __init__(self, device, bootable=True): - """Create a new DiskDevice.""" - self.device = device - self.bootable = bootable - self.progress_bar = None - - self.g = guestfs.GuestFS() - self.g.add_drive_opts(device, readonly=0) - - #self.g.set_trace(1) - #self.g.set_verbose(1) - - eh = self.g.set_event_callback(self.progress_callback, guestfs.EVENT_PROGRESS) - self.g.launch() - self.g.delete_event_callback(eh) - - roots = self.g.inspect_os() - if len(roots) == 0: - raise DiskError("No operating system found") - if len(roots) > 1: - raise DiskError("Multiple operating systems found") - - self.root = roots[0] - self.ostype = self.g.inspect_get_type(self.root) - self.distro = self.g.inspect_get_distro(self.root) - - def destroy(self): - """Destroy this DiskDevice instance.""" - self.g.umount_all() - self.g.sync() - # Close the guestfs handler - self.g.close() - - def progress_callback(self, ev, eh, buf, array): - position = array[2] - total = array[3] - - if self.progress_bar is None: - self.progress_bar = progress_generator(total) - self.progress_bar.next() - - self.progress_bar.send(position) - - if position == total: - self.progress_bar = None - - def mount(self): - """Mount all disk partitions in a correct order.""" - mps = self.g.inspect_get_mountpoints(self.root) - - # Sort the keys to mount the fs in a correct order. - # / should be mounted befor /boot, etc - def compare(a, b): - if len(a[0]) > len(b[0]): - return 1 - elif len(a[0]) == len(b[0]): - return 0 - else: - return -1 - mps.sort(compare) - for mp, dev in mps: - try: - self.g.mount(dev, mp) - except RuntimeError as msg: - print "%s (ignored)" % msg - - def umount(self): - """Umount all mounted filesystems.""" - self.g.umount_all() - - def shrink(self): - """Shrink the disk. - - This is accomplished by shrinking the last filesystem in the - disk and then updating the partition table. The new disk size - (in bytes) is returned. + def destroy_image(self, image): + """Destroys an Image instance previously created by get_image method. """ - dev = self.g.part_to_dev(self.root) - parttype = self.g.part_get_parttype(dev) - if parttype != 'msdos': - raise DiskError("You have a %s partition table. " - "Only msdos partitions are supported" % parttype) - - last_partition = self.g.part_list(dev)[-1] - - if last_partition['part_num'] > 4: - raise DiskError("This disk contains logical partitions. " - "Only primary partitions are supported.") - - part_dev = "%s%d" % (dev, last_partition['part_num']) - fs_type = self.g.vfs_type(part_dev) - if not re.match("ext[234]", fs_type): - print "Warning: Don't know how to resize %s partitions." % vfs_type - return - - self.g.e2fsck_f(part_dev) - self.g.resize2fs_M(part_dev) - output = self.g.tune2fs_l(part_dev) - block_size = int(filter(lambda x: x[0] == 'Block size', output)[0][1]) - block_cnt = int(filter(lambda x: x[0] == 'Block count', output)[0][1]) - - sector_size = self.g.blockdev_getss(dev) - - start = last_partition['part_start'] / sector_size - end = start + (block_size * block_cnt) / sector_size - 1 - - self.g.part_del(dev, last_partition['part_num']) - self.g.part_add(dev, 'p', start, end) - - return (end + 1) * sector_size - - def size(self): - """Returns the "payload" size of the device. - - The size returned by this method is the size of the space occupied by - the partitions (including the space before the first partition). - """ - dev = self.g.part_to_dev(self.root) - last = self.g.part_list(dev)[-1] - - return last['part_end'] + self._images.remove(image) + image.destroy() # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :