X-Git-Url: https://code.grnet.gr/git/snf-image-creator/blobdiff_plain/c16850ae1ce37e8fed14320c55233e272bed4e69..88f83027df65608a70e1a88f96b4a3055427dd52:/image_creator/bundle_volume.py diff --git a/image_creator/bundle_volume.py b/image_creator/bundle_volume.py index fc35352..c4cc83c 100644 --- a/image_creator/bundle_volume.py +++ b/image_creator/bundle_volume.py @@ -34,6 +34,7 @@ import os import re import tempfile +import uuid from collections import namedtuple import parted @@ -43,6 +44,7 @@ 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') @@ -90,6 +92,7 @@ class BundleVolume(object): self.disk = parted.Disk(device) def _read_fstable(self, f): + """Use this generator to iterate over the lines of and fstab file""" if not os.path.isfile(f): raise FatalError("Unable to open: `%s'. File is missing." % f) @@ -104,6 +107,7 @@ class BundleVolume(object): yield FileSystemTableEntry(*entry) def _get_root_partition(self): + """Return the fstab entry accosiated with the root filesystem""" for entry in self._read_fstable('/etc/fstab'): if entry.mpoint == '/': return entry.dev @@ -111,12 +115,14 @@ class BundleVolume(object): raise FatalError("Unable to find root device in /etc/fstab") def _is_mpoint(self, path): + """Check if a directory is currently a mount point""" for entry in self._read_fstable('/proc/mounts'): if entry.mpoint == path: return True return False def _get_mount_options(self, device): + """Return the mount entry associated with a mounted device""" for entry in self._read_fstable('/proc/mounts'): if not entry.dev.startswith('/'): continue @@ -127,18 +133,25 @@ class BundleVolume(object): return None def _create_partition_table(self, image): - - if self.disk.type != 'msdos': - raise FatalError('Only msdos partition tables are supported') + """Copy the partition table of the host system into the image""" # Copy the MBR and the space between the MBR and the first partition. - # In Grub version 1 Stage 1.5 is located there. + # 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: @@ -155,6 +168,7 @@ class BundleVolume(object): start = logical[i].geometry.end + 1 def _get_partitions(self, disk): + """Returns a list with the partitions of the provided disk""" Partition = namedtuple('Partition', 'num start end type fs') partitions = [] @@ -169,11 +183,13 @@ class BundleVolume(object): return partitions def _shrink_partitions(self, image): + """Remove the last partition of the image if it is a swap partition and + shrink the partition before that. Make sure it can still host all the + files the corresponding host file system hosts + """ + new_end = self.disk.device.length - new_end = self.disk.device.getLength() - - image_dev = parted.Device(image) - image_disk = parted.Disk(image_dev) + 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 @@ -188,19 +204,18 @@ class BundleVolume(object): image_disk.deletePartition( image_disk.getPartitionBySector(last.start)) - image_disk.commit() + image_disk.commitToDevice() if is_logical(last) and last.num == 5: extended = image_disk.getExtendedPartition() image_disk.deletePartition(extended) - image_disk.commit() + image_disk.commitToDevice() partitions.remove(filter(is_extended, partitions)[0]) partitions.remove(last) last = partitions[-1] - # Leave 2048 blocks at the end - new_end = last.end + 2048 + new_end = last.end mount_options = self._get_mount_options( self.disk.getPartitionBySector(last.start).path) @@ -216,34 +231,32 @@ class BundleVolume(object): # 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), - parted.Constraint(device=image_disk.device), + image_disk.getPartitionBySector(last.start), constraint, start=last.start, end=part_end) - image_disk.commit() + 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 - # Leave 2048 blocks at the end. - new_end = part_end + 2048 + new_end = part_end if last.type == parted.PARTITION_LOGICAL: # Fix the extended partition - extended = disk.getExtendedPartition() - - image_disk.setPartitionGeometry( - extended, parted.Constraint(device=img_dev), - ext.geometry.start, end=last.end) - image_disk.commit() + image_disk.minimizeExtendedPartition() - image_dev.destroy() - return new_end + return (new_end, self._get_partitions(image_disk)) def _map_partition(self, dev, num, start, end): - name = os.path.basename(dev) + """Map a partition into a block device using the device mapper""" + name = os.path.basename(dev) + "_" + uuid.uuid4().hex tablefd, table = tempfile.mkstemp() try: size = end - start + 1 @@ -255,13 +268,14 @@ class BundleVolume(object): return "/dev/mapper/%sp%d" % (name, num) def _unmap_partition(self, dev): + """Unmap a previously mapped partition""" if not os.path.exists(dev): return try_fail_repeat(dmsetup, 'remove', dev.split('/dev/mapper/')[1]) def _mount(self, target, devs): - + """Mount a list of filesystems in mountpoints relative to target""" devs.sort(key=lambda d: d[1]) for dev, mpoint in devs: absmpoint = os.path.abspath(target + mpoint) @@ -270,6 +284,8 @@ class BundleVolume(object): mount(dev, absmpoint) def _umount_all(self, target): + """Unmount all filesystems that are mounted under the directory target + """ mpoints = [] for entry in self._read_fstable('/proc/mounts'): if entry.mpoint.startswith(os.path.abspath(target)): @@ -280,6 +296,10 @@ class BundleVolume(object): try_fail_repeat(umount, mpoint) def _to_exclude(self): + """Find which directories to exclude during the image copy. This is + accompliced by checking which directories serve as mount points for + virtual file systems + """ excluded = ['/tmp', '/var/tmp'] if self.tmp is not None: excluded.append(self.tmp) @@ -312,23 +332,25 @@ class BundleVolume(object): if not found_ancestor: excluded.append(mpoint) - return map(lambda d: d + "/*", excluded) + return excluded def _replace_uuids(self, target, new_uuid): + """Replace UUID references in various files. This is needed after + copying system files of the host into a new filesystem + """ files = ['/etc/fstab', '/boot/grub/grub.cfg', '/boot/grub/menu.lst', '/boot/grub/grub.conf'] - orig = dict(map( - lambda p: ( - p.number, - blkid('-s', 'UUID', '-o', 'value', p.path).stdout.strip()), - self.disk.partitions)) + 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 @@ -340,22 +362,27 @@ class BundleVolume(object): line = re.sub(orig[i], uuid, line) dest.write(line) - def _create_filesystems(self, image): + def _create_filesystems(self, image, partitions): + """Fill the image with data. Host file systems that are not currently + mounted are binary copied into the image. For mounted file systems, a + file system level copy is performed. + """ filesystem = {} for p in self.disk.partitions: filesystem[p.number] = self._get_mount_options(p.path) - partitions = self._get_partitions(parted.Disk(parted.Device(image))) 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 = {} @@ -377,19 +404,41 @@ class BundleVolume(object): target = tempfile.mkdtemp() try: - absmpoints = self._mount(target, - [(mapped[i], filesystem[i].mpoint) - for i in mapped.keys()]) - exclude = self._to_exclude() + [image] + 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: os.path.relpath(p, '/'), exclude): + for excl in excluded + [image]: rsync.exclude(excl) rsync.archive().hard_links().xattrs().sparse().acls() - rsync.run('/', target, 'host', 'tmp image') + 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 @@ -409,7 +458,7 @@ class BundleVolume(object): running system. """ - size = self.disk.device.getLength() * self.disk.device.sectorSize + 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) @@ -419,10 +468,17 @@ class BundleVolume(object): os.close(fd) self._create_partition_table(image) - - end_sector = self._shrink_partitions(image) - - size = (end_sector + 1) * self.disk.device.sectorSize + 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) @@ -433,13 +489,13 @@ class BundleVolume(object): # Check if the available space is enough to host the image dirname = os.path.dirname(image) - self.out.output("Examining available space in %s ..." % dirname, False) + self.out.output("Examining available space ...", False) if free_space(dirname) <= size: - raise FatalError('Not enough space in %s to host the image' % - dirname) + raise FatalError("Not enough space under %s to host the temporary " + "image" % dirname) self.out.success("sufficient") - self._create_filesystems(image) + self._create_filesystems(image, partitions) return image