# Copyright 2012 GRNET S.A. All rights reserved.
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import os
import re
import tempfile
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
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):
"""Create an instance of the BundleVolume class."""
self.out = out
self.meta = meta
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):
if self.disk.type != 'msdos':
raise FatalError('Only msdos partition tables are supported')
# Copy the MBR and the space between the MBR and the first partition.
# In Grub version 1 Stage 1.5 is located 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')
# 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.getLength()
image_dev = parted.Device(image)
image_disk = parted.Disk(image_dev)
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.commit()
if is_logical(last) and last.num == 5:
extended = image_disk.getExtendedPartition()
image_disk.deletePartition(extended)
image_disk.commit()
partitions.remove(filter(is_extended, partitions)[0])
partitions.remove(last)
last = partitions[-1]
# Leave 2048 blocks at the end
new_end = last.end + 2048
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
# Alighn to 2048
part_end = ((part_end + 2047) // 2048) * 2048
image_disk.setPartitionGeometry(
image_disk.getPartitionBySector(last.start),
parted.Constraint(device=image_disk.device),
start=last.start, end=part_end)
image_disk.commit()
# 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
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_dev.destroy()
return new_end
def _map_partition(self, dev, num, start, end):
name = os.path.basename(dev)
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']
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 map(lambda d: d + "/*", excluded)
def _replace_uuids(self, target, new_uuid):
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))
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):
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:
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)
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()]
)
exclude = self._to_exclude() + [image]
rsync = Rsync('/', target,
map(lambda p: os.path.relpath(p, '/'), exclude))
rsync.archive().run(self.out)
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.getLength() * 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 = self._shrink_partitions(image)
# Check if the available space is enough to host the image
dirname = os.path.dirname(image)
size = (end_sector + 1) * self.disk.device.sectorSize
self.out.output("Examining available space in %s ..." % dirname, False)
stat = os.statvfs(dirname)
available = stat.f_bavail * stat.f_frsize
if available <= size:
raise FatalError('Not enough space in %s to host the image' %
dirname)
self.out.success("sufficient")
self._create_filesystems(image)
# Truncate image to the new size. I counldn't find a better way to do
# this. It seems that python's high level functions work in a different
# way.
fd = os.open(image, os.O_RDWR)
try:
os.ftruncate(fd, size)
finally:
os.close(fd)
return image
# vim: set sta sts=4 shiftwidth=4 sw=4 et ai :