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)
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
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
return None
def _create_partition_table(self, image):
+ """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 msdos partition tables Grub Stage 1.5 is located there.
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 = []
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
image_disk = parted.Disk(parted.Device(image))
return (new_end, self._get_partitions(image_disk))
def _map_partition(self, dev, num, start, end):
+ """Map a partition into a block device using the device mapper"""
name = os.path.basename(dev) + "_" + uuid.uuid4().hex
tablefd, table = tempfile.mkstemp()
try:
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)
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)):
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)
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',
dest.write(line)
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:
target = tempfile.mkdtemp()
try:
- absmpoints = self._mount(target,
- [(mapped[i], filesystem[i].mpoint)
- for i in mapped.keys()])
+ 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]):
+ for excl in excluded + [image]:
rsync.exclude(excl)
rsync.archive().hard_links().xattrs().sparse().acls()
for excl in excluded:
dirname = os.path.dirname(excl)
stat = os.stat(dirname)
- os.mkdir(target + excl, stat.st_mode)
+ 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.
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)
+ raise FatalError("Not enough space under %s to host the temporary "
+ "image" % dirname)
self.out.success("sufficient")
self._create_filesystems(image, partitions)
projects / snf-image-creator / blobdiff