Don't check the token if -t is not defined
[snf-image-creator] / image_creator / bundle_volume.py
index 2051738..a6fc27a 100644 (file)
 # 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 :