X-Git-Url: https://code.grnet.gr/git/snf-image-creator/blobdiff_plain/9e4b4de20ef2c2c23a96fb1ac5d474fa2370695e..c2cf27e81001fddf3ed834665804a4f64290947e:/image_creator/bundle_volume.py diff --git a/image_creator/bundle_volume.py b/image_creator/bundle_volume.py index 2051738..a6fc27a 100644 --- a/image_creator/bundle_volume.py +++ b/image_creator/bundle_volume.py @@ -31,10 +31,448 @@ # interpreted as representing official policies, either expressed # or implied, of GRNET S.A. +import os +import re +import tempfile +import uuid +from collections import namedtuple + +import parted + +from image_creator.rsync import Rsync +from image_creator.util import get_command from image_creator.util import FatalError +from image_creator.util import try_fail_repeat +from image_creator.util import free_space +from image_creator.gpt import GPTPartitionTable + +findfs = get_command('findfs') +dd = get_command('dd') +dmsetup = get_command('dmsetup') +losetup = get_command('losetup') +mount = get_command('mount') +umount = get_command('umount') +blkid = get_command('blkid') + +MKFS_OPTS = {'ext2': ['-F'], + 'ext3': ['-F'], + 'ext4': ['-F'], + 'reiserfs': ['-ff'], + 'btrfs': [], + 'minix': [], + 'xfs': ['-f'], + 'jfs': ['-f'], + 'ntfs': ['-F'], + 'msdos': [], + 'vfat': []} + + +class BundleVolume(object): + """This class can be used to create an image out of the running system""" + + def __init__(self, out, meta, tmp=None): + """Create an instance of the BundleVolume class.""" + self.out = out + self.meta = meta + self.tmp = tmp + + self.out.output('Searching for root device ...', False) + root = self._get_root_partition() + + if root.startswith("UUID=") or root.startswith("LABEL="): + root = findfs(root).stdout.strip() + + if not re.match('/dev/[hsv]d[a-z][1-9]*$', root): + raise FatalError("Don't know how to handle root device: %s" % root) + + out.success(root) + + disk_file = re.split('[0-9]', root)[0] + device = parted.Device(disk_file) + self.disk = parted.Disk(device) + + def _read_fstable(self, f): + + if not os.path.isfile(f): + raise FatalError("Unable to open: `%s'. File is missing." % f) + + FileSystemTableEntry = namedtuple('FileSystemTableEntry', + 'dev mpoint fs opts freq passno') + with open(f) as table: + for line in iter(table): + entry = line.split('#')[0].strip().split() + if len(entry) != 6: + continue + yield FileSystemTableEntry(*entry) + + def _get_root_partition(self): + for entry in self._read_fstable('/etc/fstab'): + if entry.mpoint == '/': + return entry.dev + + raise FatalError("Unable to find root device in /etc/fstab") + + def _is_mpoint(self, path): + for entry in self._read_fstable('/proc/mounts'): + if entry.mpoint == path: + return True + return False + + def _get_mount_options(self, device): + for entry in self._read_fstable('/proc/mounts'): + if not entry.dev.startswith('/'): + continue + + if os.path.realpath(entry.dev) == os.path.realpath(device): + return entry + + return None + + def _create_partition_table(self, image): + + # Copy the MBR and the space between the MBR and the first partition. + # In msdos partition tables Grub Stage 1.5 is located there. + # In gpt partition tables the Primary GPT Header is there. + first_sector = self.disk.getPrimaryPartitions()[0].geometry.start + + dd('if=%s' % self.disk.device.path, 'of=%s' % image, + 'bs=%d' % self.disk.device.sectorSize, + 'count=%d' % first_sector, 'conv=notrunc') + + if self.disk.type == 'gpt': + # Copy the Secondary GPT Header + table = GPTPartitionTable(self.disk.device.path) + dd('if=%s' % self.disk.device.path, 'of=%s' % image, + 'bs=%d' % self.disk.device.sectorSize, 'conv=notrunc', + 'seek=%d' % table.primary.last_usable_lba, + 'skip=%d' % table.primary.last_usable_lba) + + # Create the Extended boot records (EBRs) in the image + extended = self.disk.getExtendedPartition() + if not extended: + return + + # Extended boot records precede the logical partitions they describe + logical = self.disk.getLogicalPartitions() + start = extended.geometry.start + for i in range(len(logical)): + end = logical[i].geometry.start - 1 + dd('if=%s' % self.disk.device.path, 'of=%s' % image, + 'count=%d' % (end - start + 1), 'conv=notrunc', + 'seek=%d' % start, 'skip=%d' % start) + start = logical[i].geometry.end + 1 + + def _get_partitions(self, disk): + Partition = namedtuple('Partition', 'num start end type fs') + + partitions = [] + for p in disk.partitions: + num = p.number + start = p.geometry.start + end = p.geometry.end + ptype = p.type + fs = p.fileSystem.type if p.fileSystem is not None else '' + partitions.append(Partition(num, start, end, ptype, fs)) + + return partitions + + def _shrink_partitions(self, image): + + new_end = self.disk.device.length + + image_disk = parted.Disk(parted.Device(image)) + + is_extended = lambda p: p.type == parted.PARTITION_EXTENDED + is_logical = lambda p: p.type == parted.PARTITION_LOGICAL + + partitions = self._get_partitions(self.disk) + + last = partitions[-1] + if last.fs == 'linux-swap(v1)': + MB = 2 ** 20 + size = (last.end - last.start + 1) * self.disk.device.sectorSize + self.meta['SWAP'] = "%d:%s" % (last.num, (size + MB - 1) // MB) + + image_disk.deletePartition( + image_disk.getPartitionBySector(last.start)) + image_disk.commitToDevice() + + if is_logical(last) and last.num == 5: + extended = image_disk.getExtendedPartition() + image_disk.deletePartition(extended) + image_disk.commitToDevice() + partitions.remove(filter(is_extended, partitions)[0]) + + partitions.remove(last) + last = partitions[-1] + + new_end = last.end + + mount_options = self._get_mount_options( + self.disk.getPartitionBySector(last.start).path) + if mount_options is not None: + stat = os.statvfs(mount_options.mpoint) + # Shrink the last partition. The new size should be the size of the + # occupied blocks + blcks = stat.f_blocks - stat.f_bavail + new_size = (blcks * stat.f_frsize) // self.disk.device.sectorSize + + # Add 10% just to be on the safe side + part_end = last.start + (new_size * 11) // 10 + # Align to 2048 + part_end = ((part_end + 2047) // 2048) * 2048 + + # Make sure the partition starts where the old partition started. + constraint = parted.Constraint(device=image_disk.device) + constraint.startRange = parted.Geometry(device=image_disk.device, + start=last.start, length=1) + + image_disk.setPartitionGeometry( + image_disk.getPartitionBySector(last.start), constraint, + start=last.start, end=part_end) + image_disk.commitToDevice() + + # Parted may have changed this for better alignment + part_end = image_disk.getPartitionBySector(last.start).geometry.end + last = last._replace(end=part_end) + partitions[-1] = last + + new_end = part_end + + if last.type == parted.PARTITION_LOGICAL: + # Fix the extended partition + image_disk.minimizeExtendedPartition() + + return (new_end, self._get_partitions(image_disk)) + + def _map_partition(self, dev, num, start, end): + name = os.path.basename(dev) + "_" + uuid.uuid4().hex + tablefd, table = tempfile.mkstemp() + try: + size = end - start + 1 + os.write(tablefd, "0 %d linear %s %d" % (size, dev, start)) + dmsetup('create', "%sp%d" % (name, num), table) + finally: + os.unlink(table) + + return "/dev/mapper/%sp%d" % (name, num) + + def _unmap_partition(self, dev): + if not os.path.exists(dev): + return + + try_fail_repeat(dmsetup, 'remove', dev.split('/dev/mapper/')[1]) + + def _mount(self, target, devs): + + devs.sort(key=lambda d: d[1]) + for dev, mpoint in devs: + absmpoint = os.path.abspath(target + mpoint) + if not os.path.exists(absmpoint): + os.makedirs(absmpoint) + mount(dev, absmpoint) + + def _umount_all(self, target): + mpoints = [] + for entry in self._read_fstable('/proc/mounts'): + if entry.mpoint.startswith(os.path.abspath(target)): + mpoints.append(entry.mpoint) + + mpoints.sort() + for mpoint in reversed(mpoints): + try_fail_repeat(umount, mpoint) + + def _to_exclude(self): + excluded = ['/tmp', '/var/tmp'] + if self.tmp is not None: + excluded.append(self.tmp) + local_filesystems = MKFS_OPTS.keys() + ['rootfs'] + for entry in self._read_fstable('/proc/mounts'): + if entry.fs in local_filesystems: + continue + + mpoint = entry.mpoint + if mpoint in excluded: + continue + + descendants = filter( + lambda p: p.startswith(mpoint + '/'), excluded) + if len(descendants): + for d in descendants: + excluded.remove(d) + excluded.append(mpoint) + continue + + dirname = mpoint + basename = '' + found_ancestor = False + while dirname != '/': + (dirname, basename) = os.path.split(dirname) + if dirname in excluded: + found_ancestor = True + break + + if not found_ancestor: + excluded.append(mpoint) + + return excluded + + def _replace_uuids(self, target, new_uuid): + + files = ['/etc/fstab', + '/boot/grub/grub.cfg', + '/boot/grub/menu.lst', + '/boot/grub/grub.conf'] + + orig = {} + for p in self.disk.partitions: + if p.number in new_uuid.keys(): + orig[p.number] = \ + blkid('-s', 'UUID', '-o', 'value', p.path).stdout.strip() + + for f in map(lambda f: target + f, files): + if not os.path.exists(f): + continue + + with open(f, 'r') as src: + lines = src.readlines() + with open(f, 'w') as dest: + for line in lines: + for i, uuid in new_uuid.items(): + line = re.sub(orig[i], uuid, line) + dest.write(line) + + def _create_filesystems(self, image, partitions): + + filesystem = {} + for p in self.disk.partitions: + filesystem[p.number] = self._get_mount_options(p.path) + + unmounted = filter(lambda p: filesystem[p.num] is None, partitions) + mounted = filter(lambda p: filesystem[p.num] is not None, partitions) + + # For partitions that are not mounted right now, we can simply dd them + # into the image. + for p in unmounted: + self.out.output('Cloning partition %d ... ' % p.num, False) + dd('if=%s' % self.disk.device.path, 'of=%s' % image, + 'count=%d' % (p.end - p.start + 1), 'conv=notrunc', + 'seek=%d' % p.start, 'skip=%d' % p.start) + self.out.success("done") + + loop = str(losetup('-f', '--show', image)).strip() + mapped = {} + try: + for p in mounted: + i = p.num + mapped[i] = self._map_partition(loop, i, p.start, p.end) + + new_uuid = {} + # Create the file systems + for i, dev in mapped.iteritems(): + fs = filesystem[i].fs + self.out.output('Creating %s filesystem on partition %d ... ' % + (fs, i), False) + get_command('mkfs.%s' % fs)(*(MKFS_OPTS[fs] + [dev])) + self.out.success('done') + new_uuid[i] = blkid( + '-s', 'UUID', '-o', 'value', dev).stdout.strip() + + target = tempfile.mkdtemp() + try: + absmpoints = self._mount(target, + [(mapped[i], filesystem[i].mpoint) + for i in mapped.keys()]) + excluded = self._to_exclude() + + rsync = Rsync(self.out) + + # Excluded paths need to be relative to the source + for excl in map(lambda p: p[1:], excluded + [image]): + rsync.exclude(excl) + + rsync.archive().hard_links().xattrs().sparse().acls() + rsync.run('/', target, 'host', 'temporary image') + + # Create missing mountpoints. Since they are mountpoints, we + # cannot determine the ownership and the mode of the real + # directory. Make them inherit those properties from their + # parent dir + for excl in excluded: + dirname = os.path.dirname(excl) + stat = os.stat(dirname) + os.mkdir(target + excl) + os.chmod(target + excl, stat.st_mode) + os.chown(target + excl, stat.st_uid, stat.st_gid) + + # /tmp and /var/tmp are special cases. We exclude then even if + # they aren't mountpoints. Restore their permissions. + for excl in ('/tmp', '/var/tmp'): + if self._is_mpoint(excl): + os.chmod(target + excl, 041777) + os.chown(target + excl, 0, 0) + else: + stat = os.stat(excl) + os.chmod(target + excl, stat.st_mode) + os.chown(target + excl, stat.st_uid, stat.st_gid) + + # We need to replace the old UUID referencies with the new + # ones in grub configuration files and /etc/fstab for file + # systems that have been recreated. + self._replace_uuids(target, new_uuid) + + finally: + self._umount_all(target) + os.rmdir(target) + finally: + for dev in mapped.values(): + self._unmap_partition(dev) + losetup('-d', loop) + + def create_image(self, image): + """Given an image filename, this method will create an image out of the + running system. + """ + + size = self.disk.device.length * self.disk.device.sectorSize + + # Create sparse file to host the image + fd = os.open(image, os.O_WRONLY | os.O_CREAT) + try: + os.ftruncate(fd, size) + finally: + os.close(fd) + + self._create_partition_table(image) + end_sector, partitions = self._shrink_partitions(image) + + if self.disk.type == 'gpt': + old_size = size + size = (end_sector + 1) * self.disk.device.sectorSize + ptable = GPTPartitionTable(image) + size = ptable.shrink(size, old_size) + else: + # Alighn to 2048 + end_sector = ((end_sector + 2047) // 2048) * 2048 + size = (end_sector + 1) * self.disk.device.sectorSize + + # Truncate image to the new size. + fd = os.open(image, os.O_RDWR) + try: + os.ftruncate(fd, size) + finally: + os.close(fd) + + # Check if the available space is enough to host the image + dirname = os.path.dirname(image) + self.out.output("Examining available space ...", False) + if free_space(dirname) <= size: + raise FatalError('Not enough space under %s to host the image' % + dirname) + self.out.success("sufficient") + + self._create_filesystems(image, partitions) -def bundle_volume(): - raise FatalError("Creating an image out of a running system is not yet " - "supported.") + return image # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :