+# -*- coding: utf-8 -*-
+#
# Copyright 2012 GRNET S.A. All rights reserved.
#
# Redistribution and use in source and binary forms, with or
# interpreted as representing official policies, either expressed
# or implied, of GRNET S.A.
+"""This module hosts the code that performes the host bundling operation. By
+using the create_image method of the BundleVolume class the user can create an
+image out of the running system.
+"""
+
import os
import re
import tempfile
mount = get_command('mount')
umount = get_command('umount')
blkid = get_command('blkid')
+tune2fs = get_command('tune2fs')
MKFS_OPTS = {'ext2': ['-F'],
'ext3': ['-F'],
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:
- size = end - start + 1
- os.write(tablefd, "0 %d linear %s %d" % (size, dev, start))
+ try:
+ size = end - start + 1
+ os.write(tablefd, "0 %d linear %s %d" % (size, dev, start))
+ finally:
+ os.close(tablefd)
dmsetup('create', "%sp%d" % (name, num), table)
finally:
os.unlink(table)
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:
+ for dev, mpoint, options in devs:
absmpoint = os.path.abspath(target + mpoint)
if not os.path.exists(absmpoint):
os.makedirs(absmpoint)
- mount(dev, absmpoint)
+
+ if len(options) > 0:
+ mount(dev, absmpoint, '-o', ",".join(options))
+ else:
+ 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)):
- mpoints.append(entry.mpoint)
+ mpoints.append(entry.mpoint)
mpoints.sort()
for mpoint in reversed(mpoints):
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)
continue
dirname = mpoint
- basename = ''
found_ancestor = False
while dirname != '/':
- (dirname, basename) = os.path.split(dirname)
+ (dirname, _) = os.path.split(dirname)
if dirname in excluded:
found_ancestor = True
break
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 = {}
+ orig_dev = {}
for p in self.disk.partitions:
filesystem[p.number] = self._get_mount_options(p.path)
+ orig_dev[p.number] = p.path
unmounted = filter(lambda p: filesystem[p.num] is None, partitions)
mounted = filter(lambda p: filesystem[p.num] is not None, partitions)
self.out.success("done")
loop = str(losetup('-f', '--show', image)).strip()
+
+ # Recreate mounted file systems
mapped = {}
try:
for p in mounted:
self.out.output('Creating %s filesystem on partition %d ... ' %
(fs, i), False)
get_command('mkfs.%s' % fs)(*(MKFS_OPTS[fs] + [dev]))
+
+ # For ext[234] enable the default mount options
+ if re.match('^ext[234]$', fs):
+ mopts = filter(
+ lambda p: p.startswith('Default mount options:'),
+ tune2fs('-l', orig_dev[i]).splitlines()
+ )[0].split(':')[1].strip().split()
+
+ if not (len(mopts) == 1 and mopts[0] == '(none)'):
+ for opt in mopts:
+ tune2fs('-o', opt, dev)
+
self.out.success('done')
new_uuid[i] = blkid(
'-s', 'UUID', '-o', 'value', dev).stdout.strip()
target = tempfile.mkdtemp()
+ devs = []
+ for i in mapped.keys():
+ fs = filesystem[i].fs
+ mpoint = filesystem[i].mpoint
+ opts = []
+ for opt in filesystem[i].opts.split(','):
+ if opt in ('acl', 'user_xattr'):
+ opts.append(opt)
+ devs.append((mapped[i], mpoint, opts))
try:
- self._mount(
- target,
- [(mapped[i], filesystem[i].mpoint) for i in mapped.keys()])
+ self._mount(target, devs)
excluded = self._to_exclude()
projects / snf-image-creator / blobdiff