root / image_creator / bundle_volume.py @ 12c97404
History | View | Annotate | Download (19.9 kB)
1 |
# -*- coding: utf-8 -*-
|
---|---|
2 |
#
|
3 |
# Copyright 2012 GRNET S.A. All rights reserved.
|
4 |
#
|
5 |
# Redistribution and use in source and binary forms, with or
|
6 |
# without modification, are permitted provided that the following
|
7 |
# conditions are met:
|
8 |
#
|
9 |
# 1. Redistributions of source code must retain the above
|
10 |
# copyright notice, this list of conditions and the following
|
11 |
# disclaimer.
|
12 |
#
|
13 |
# 2. Redistributions in binary form must reproduce the above
|
14 |
# copyright notice, this list of conditions and the following
|
15 |
# disclaimer in the documentation and/or other materials
|
16 |
# provided with the distribution.
|
17 |
#
|
18 |
# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
|
19 |
# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
20 |
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
21 |
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
|
22 |
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
23 |
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
24 |
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
|
25 |
# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
26 |
# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
27 |
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
28 |
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
29 |
# POSSIBILITY OF SUCH DAMAGE.
|
30 |
#
|
31 |
# The views and conclusions contained in the software and
|
32 |
# documentation are those of the authors and should not be
|
33 |
# interpreted as representing official policies, either expressed
|
34 |
# or implied, of GRNET S.A.
|
35 |
|
36 |
"""This module hosts the code that performes the host bundling operation. By
|
37 |
using the create_image method of the BundleVolume class the user can create an
|
38 |
image out of the running system.
|
39 |
"""
|
40 |
|
41 |
import os |
42 |
import re |
43 |
import tempfile |
44 |
import uuid |
45 |
from collections import namedtuple |
46 |
|
47 |
import parted |
48 |
|
49 |
from image_creator.rsync import Rsync |
50 |
from image_creator.util import get_command |
51 |
from image_creator.util import FatalError |
52 |
from image_creator.util import try_fail_repeat |
53 |
from image_creator.util import free_space |
54 |
from image_creator.gpt import GPTPartitionTable |
55 |
|
56 |
findfs = get_command('findfs')
|
57 |
dd = get_command('dd')
|
58 |
dmsetup = get_command('dmsetup')
|
59 |
losetup = get_command('losetup')
|
60 |
mount = get_command('mount')
|
61 |
umount = get_command('umount')
|
62 |
blkid = get_command('blkid')
|
63 |
tune2fs = get_command('tune2fs')
|
64 |
|
65 |
MKFS_OPTS = {'ext2': ['-F'], |
66 |
'ext3': ['-F'], |
67 |
'ext4': ['-F'], |
68 |
'reiserfs': ['-ff'], |
69 |
'btrfs': [],
|
70 |
'minix': [],
|
71 |
'xfs': ['-f'], |
72 |
'jfs': ['-f'], |
73 |
'ntfs': ['-F'], |
74 |
'msdos': [],
|
75 |
'vfat': []}
|
76 |
|
77 |
|
78 |
class BundleVolume(object): |
79 |
"""This class can be used to create an image out of the running system"""
|
80 |
|
81 |
def __init__(self, out, meta, tmp=None): |
82 |
"""Create an instance of the BundleVolume class."""
|
83 |
self.out = out
|
84 |
self.meta = meta
|
85 |
self.tmp = tmp
|
86 |
|
87 |
self.out.output('Searching for root device ...', False) |
88 |
root = self._get_root_partition()
|
89 |
|
90 |
if root.startswith("UUID=") or root.startswith("LABEL="): |
91 |
root = findfs(root).stdout.strip() |
92 |
|
93 |
if not re.match('/dev/[hsv]d[a-z][1-9]*$', root): |
94 |
raise FatalError("Don't know how to handle root device: %s" % root) |
95 |
|
96 |
out.success(root) |
97 |
|
98 |
disk_file = re.split('[0-9]', root)[0] |
99 |
device = parted.Device(disk_file) |
100 |
self.disk = parted.Disk(device)
|
101 |
|
102 |
def _read_fstable(self, f): |
103 |
"""Use this generator to iterate over the lines of and fstab file"""
|
104 |
|
105 |
if not os.path.isfile(f): |
106 |
raise FatalError("Unable to open: `%s'. File is missing." % f) |
107 |
|
108 |
FileSystemTableEntry = namedtuple('FileSystemTableEntry',
|
109 |
'dev mpoint fs opts freq passno')
|
110 |
with open(f) as table: |
111 |
for line in iter(table): |
112 |
entry = line.split('#')[0].strip().split() |
113 |
if len(entry) != 6: |
114 |
continue
|
115 |
yield FileSystemTableEntry(*entry)
|
116 |
|
117 |
def _get_root_partition(self): |
118 |
"""Return the fstab entry accosiated with the root filesystem"""
|
119 |
for entry in self._read_fstable('/etc/fstab'): |
120 |
if entry.mpoint == '/': |
121 |
return entry.dev
|
122 |
|
123 |
raise FatalError("Unable to find root device in /etc/fstab") |
124 |
|
125 |
def _is_mpoint(self, path): |
126 |
"""Check if a directory is currently a mount point"""
|
127 |
for entry in self._read_fstable('/proc/mounts'): |
128 |
if entry.mpoint == path:
|
129 |
return True |
130 |
return False |
131 |
|
132 |
def _get_mount_options(self, device): |
133 |
"""Return the mount entry associated with a mounted device"""
|
134 |
for entry in self._read_fstable('/proc/mounts'): |
135 |
if not entry.dev.startswith('/'): |
136 |
continue
|
137 |
|
138 |
if os.path.realpath(entry.dev) == os.path.realpath(device):
|
139 |
return entry
|
140 |
|
141 |
return None |
142 |
|
143 |
def _create_partition_table(self, image): |
144 |
"""Copy the partition table of the host system into the image"""
|
145 |
|
146 |
# Copy the MBR and the space between the MBR and the first partition.
|
147 |
# In msdos partition tables Grub Stage 1.5 is located there.
|
148 |
# In gpt partition tables the Primary GPT Header is there.
|
149 |
first_sector = self.disk.getPrimaryPartitions()[0].geometry.start |
150 |
|
151 |
dd('if=%s' % self.disk.device.path, 'of=%s' % image, |
152 |
'bs=%d' % self.disk.device.sectorSize, |
153 |
'count=%d' % first_sector, 'conv=notrunc') |
154 |
|
155 |
if self.disk.type == 'gpt': |
156 |
# Copy the Secondary GPT Header
|
157 |
table = GPTPartitionTable(self.disk.device.path)
|
158 |
dd('if=%s' % self.disk.device.path, 'of=%s' % image, |
159 |
'bs=%d' % self.disk.device.sectorSize, 'conv=notrunc', |
160 |
'seek=%d' % table.primary.last_usable_lba,
|
161 |
'skip=%d' % table.primary.last_usable_lba)
|
162 |
|
163 |
# Create the Extended boot records (EBRs) in the image
|
164 |
extended = self.disk.getExtendedPartition()
|
165 |
if not extended: |
166 |
return
|
167 |
|
168 |
# Extended boot records precede the logical partitions they describe
|
169 |
logical = self.disk.getLogicalPartitions()
|
170 |
start = extended.geometry.start |
171 |
for i in range(len(logical)): |
172 |
end = logical[i].geometry.start - 1
|
173 |
dd('if=%s' % self.disk.device.path, 'of=%s' % image, |
174 |
'count=%d' % (end - start + 1), 'conv=notrunc', |
175 |
'seek=%d' % start, 'skip=%d' % start) |
176 |
start = logical[i].geometry.end + 1
|
177 |
|
178 |
def _get_partitions(self, disk): |
179 |
"""Returns a list with the partitions of the provided disk"""
|
180 |
Partition = namedtuple('Partition', 'num start end type fs') |
181 |
|
182 |
partitions = [] |
183 |
for p in disk.partitions: |
184 |
num = p.number |
185 |
start = p.geometry.start |
186 |
end = p.geometry.end |
187 |
ptype = p.type |
188 |
fs = p.fileSystem.type if p.fileSystem is not None else '' |
189 |
partitions.append(Partition(num, start, end, ptype, fs)) |
190 |
|
191 |
return partitions
|
192 |
|
193 |
def _shrink_partitions(self, image): |
194 |
"""Remove the last partition of the image if it is a swap partition and
|
195 |
shrink the partition before that. Make sure it can still host all the
|
196 |
files the corresponding host file system hosts
|
197 |
"""
|
198 |
new_end = self.disk.device.length
|
199 |
|
200 |
image_disk = parted.Disk(parted.Device(image)) |
201 |
|
202 |
is_extended = lambda p: p.type == parted.PARTITION_EXTENDED
|
203 |
is_logical = lambda p: p.type == parted.PARTITION_LOGICAL
|
204 |
|
205 |
partitions = self._get_partitions(self.disk) |
206 |
|
207 |
last = partitions[-1]
|
208 |
if last.fs == 'linux-swap(v1)': |
209 |
MB = 2 ** 20 |
210 |
size = (last.end - last.start + 1) * self.disk.device.sectorSize |
211 |
self.meta['SWAP'] = "%d:%s" % (last.num, (size + MB - 1) // MB) |
212 |
|
213 |
image_disk.deletePartition( |
214 |
image_disk.getPartitionBySector(last.start)) |
215 |
image_disk.commitToDevice() |
216 |
|
217 |
if is_logical(last) and last.num == 5: |
218 |
extended = image_disk.getExtendedPartition() |
219 |
image_disk.deletePartition(extended) |
220 |
image_disk.commitToDevice() |
221 |
partitions.remove(filter(is_extended, partitions)[0]) |
222 |
|
223 |
partitions.remove(last) |
224 |
last = partitions[-1]
|
225 |
|
226 |
new_end = last.end |
227 |
|
228 |
mount_options = self._get_mount_options(
|
229 |
self.disk.getPartitionBySector(last.start).path)
|
230 |
if mount_options is not None: |
231 |
stat = os.statvfs(mount_options.mpoint) |
232 |
# Shrink the last partition. The new size should be the size of the
|
233 |
# occupied blocks
|
234 |
blcks = stat.f_blocks - stat.f_bavail |
235 |
new_size = (blcks * stat.f_frsize) // self.disk.device.sectorSize
|
236 |
|
237 |
# Add 10% just to be on the safe side
|
238 |
part_end = last.start + (new_size * 11) // 10 |
239 |
# Align to 2048
|
240 |
part_end = ((part_end + 2047) // 2048) * 2048 |
241 |
|
242 |
# Make sure the partition starts where the old partition started.
|
243 |
constraint = parted.Constraint(device=image_disk.device) |
244 |
constraint.startRange = parted.Geometry(device=image_disk.device, |
245 |
start=last.start, length=1)
|
246 |
|
247 |
image_disk.setPartitionGeometry( |
248 |
image_disk.getPartitionBySector(last.start), constraint, |
249 |
start=last.start, end=part_end) |
250 |
image_disk.commitToDevice() |
251 |
|
252 |
# Parted may have changed this for better alignment
|
253 |
part_end = image_disk.getPartitionBySector(last.start).geometry.end |
254 |
last = last._replace(end=part_end) |
255 |
partitions[-1] = last
|
256 |
|
257 |
new_end = part_end |
258 |
|
259 |
if last.type == parted.PARTITION_LOGICAL:
|
260 |
# Fix the extended partition
|
261 |
image_disk.minimizeExtendedPartition() |
262 |
|
263 |
return (new_end, self._get_partitions(image_disk)) |
264 |
|
265 |
def _map_partition(self, dev, num, start, end): |
266 |
"""Map a partition into a block device using the device mapper"""
|
267 |
name = os.path.basename(dev) + "_" + uuid.uuid4().hex
|
268 |
tablefd, table = tempfile.mkstemp() |
269 |
try:
|
270 |
try:
|
271 |
size = end - start + 1
|
272 |
os.write(tablefd, "0 %d linear %s %d" % (size, dev, start))
|
273 |
finally:
|
274 |
os.close(tablefd) |
275 |
dmsetup('create', "%sp%d" % (name, num), table) |
276 |
finally:
|
277 |
os.unlink(table) |
278 |
|
279 |
return "/dev/mapper/%sp%d" % (name, num) |
280 |
|
281 |
def _unmap_partition(self, dev): |
282 |
"""Unmap a previously mapped partition"""
|
283 |
if not os.path.exists(dev): |
284 |
return
|
285 |
|
286 |
try_fail_repeat(dmsetup, 'remove', dev.split('/dev/mapper/')[1]) |
287 |
|
288 |
def _mount(self, target, devs): |
289 |
"""Mount a list of filesystems in mountpoints relative to target"""
|
290 |
devs.sort(key=lambda d: d[1]) |
291 |
for dev, mpoint, options in devs: |
292 |
absmpoint = os.path.abspath(target + mpoint) |
293 |
if not os.path.exists(absmpoint): |
294 |
os.makedirs(absmpoint) |
295 |
|
296 |
if len(options) > 0: |
297 |
mount(dev, absmpoint, '-o', ",".join(options)) |
298 |
else:
|
299 |
mount(dev, absmpoint) |
300 |
|
301 |
def _umount_all(self, target): |
302 |
"""Unmount all filesystems that are mounted under the directory target
|
303 |
"""
|
304 |
mpoints = [] |
305 |
for entry in self._read_fstable('/proc/mounts'): |
306 |
if entry.mpoint.startswith(os.path.abspath(target)):
|
307 |
mpoints.append(entry.mpoint) |
308 |
|
309 |
mpoints.sort() |
310 |
for mpoint in reversed(mpoints): |
311 |
try_fail_repeat(umount, mpoint) |
312 |
|
313 |
def _to_exclude(self): |
314 |
"""Find which directories to exclude during the image copy. This is
|
315 |
accompliced by checking which directories serve as mount points for
|
316 |
virtual file systems
|
317 |
"""
|
318 |
excluded = ['/tmp', '/var/tmp'] |
319 |
if self.tmp is not None: |
320 |
excluded.append(self.tmp)
|
321 |
local_filesystems = MKFS_OPTS.keys() + ['rootfs']
|
322 |
for entry in self._read_fstable('/proc/mounts'): |
323 |
if entry.fs in local_filesystems: |
324 |
continue
|
325 |
|
326 |
mpoint = entry.mpoint |
327 |
if mpoint in excluded: |
328 |
continue
|
329 |
|
330 |
descendants = filter(
|
331 |
lambda p: p.startswith(mpoint + '/'), excluded) |
332 |
if len(descendants): |
333 |
for d in descendants: |
334 |
excluded.remove(d) |
335 |
excluded.append(mpoint) |
336 |
continue
|
337 |
|
338 |
dirname = mpoint |
339 |
basename = ''
|
340 |
found_ancestor = False
|
341 |
while dirname != '/': |
342 |
(dirname, basename) = os.path.split(dirname) |
343 |
if dirname in excluded: |
344 |
found_ancestor = True
|
345 |
break
|
346 |
|
347 |
if not found_ancestor: |
348 |
excluded.append(mpoint) |
349 |
|
350 |
return excluded
|
351 |
|
352 |
def _replace_uuids(self, target, new_uuid): |
353 |
"""Replace UUID references in various files. This is needed after
|
354 |
copying system files of the host into a new filesystem
|
355 |
"""
|
356 |
|
357 |
files = ['/etc/fstab',
|
358 |
'/boot/grub/grub.cfg',
|
359 |
'/boot/grub/menu.lst',
|
360 |
'/boot/grub/grub.conf']
|
361 |
|
362 |
orig = {} |
363 |
for p in self.disk.partitions: |
364 |
if p.number in new_uuid.keys(): |
365 |
orig[p.number] = \ |
366 |
blkid('-s', 'UUID', '-o', 'value', p.path).stdout.strip() |
367 |
|
368 |
for f in map(lambda f: target + f, files): |
369 |
if not os.path.exists(f): |
370 |
continue
|
371 |
|
372 |
with open(f, 'r') as src: |
373 |
lines = src.readlines() |
374 |
with open(f, 'w') as dest: |
375 |
for line in lines: |
376 |
for i, uuid in new_uuid.items(): |
377 |
line = re.sub(orig[i], uuid, line) |
378 |
dest.write(line) |
379 |
|
380 |
def _create_filesystems(self, image, partitions): |
381 |
"""Fill the image with data. Host file systems that are not currently
|
382 |
mounted are binary copied into the image. For mounted file systems, a
|
383 |
file system level copy is performed.
|
384 |
"""
|
385 |
|
386 |
filesystem = {} |
387 |
orig_dev = {} |
388 |
for p in self.disk.partitions: |
389 |
filesystem[p.number] = self._get_mount_options(p.path)
|
390 |
orig_dev[p.number] = p.path |
391 |
|
392 |
unmounted = filter(lambda p: filesystem[p.num] is None, partitions) |
393 |
mounted = filter(lambda p: filesystem[p.num] is not None, partitions) |
394 |
|
395 |
# For partitions that are not mounted right now, we can simply dd them
|
396 |
# into the image.
|
397 |
for p in unmounted: |
398 |
self.out.output('Cloning partition %d ... ' % p.num, False) |
399 |
dd('if=%s' % self.disk.device.path, 'of=%s' % image, |
400 |
'count=%d' % (p.end - p.start + 1), 'conv=notrunc', |
401 |
'seek=%d' % p.start, 'skip=%d' % p.start) |
402 |
self.out.success("done") |
403 |
|
404 |
loop = str(losetup('-f', '--show', image)).strip() |
405 |
|
406 |
# Recreate mounted file systems
|
407 |
mapped = {} |
408 |
try:
|
409 |
for p in mounted: |
410 |
i = p.num |
411 |
mapped[i] = self._map_partition(loop, i, p.start, p.end)
|
412 |
|
413 |
new_uuid = {} |
414 |
# Create the file systems
|
415 |
for i, dev in mapped.iteritems(): |
416 |
fs = filesystem[i].fs |
417 |
self.out.output('Creating %s filesystem on partition %d ... ' % |
418 |
(fs, i), False)
|
419 |
get_command('mkfs.%s' % fs)(*(MKFS_OPTS[fs] + [dev]))
|
420 |
|
421 |
# For ext[234] enable the default mount options
|
422 |
if re.match('^ext[234]$', fs): |
423 |
mopts = filter(
|
424 |
lambda p: p.startswith('Default mount options:'), |
425 |
tune2fs('-l', orig_dev[i]).splitlines()
|
426 |
)[0].split(':')[1].strip().split() |
427 |
|
428 |
if not (len(mopts) == 1 and mopts[0] == '(none)'): |
429 |
for opt in mopts: |
430 |
tune2fs('-o', opt, dev)
|
431 |
|
432 |
self.out.success('done') |
433 |
new_uuid[i] = blkid( |
434 |
'-s', 'UUID', '-o', 'value', dev).stdout.strip() |
435 |
|
436 |
target = tempfile.mkdtemp() |
437 |
devs = [] |
438 |
for i in mapped.keys(): |
439 |
fs = filesystem[i].fs |
440 |
mpoint = filesystem[i].mpoint |
441 |
opts = [] |
442 |
for opt in filesystem[i].opts.split(','): |
443 |
if opt in ('acl', 'user_xattr'): |
444 |
opts.append(opt) |
445 |
devs.append((mapped[i], mpoint, opts)) |
446 |
try:
|
447 |
self._mount(target, devs)
|
448 |
|
449 |
excluded = self._to_exclude()
|
450 |
|
451 |
rsync = Rsync(self.out)
|
452 |
|
453 |
for excl in excluded + [image]: |
454 |
rsync.exclude(excl) |
455 |
|
456 |
rsync.archive().hard_links().xattrs().sparse().acls() |
457 |
rsync.run('/', target, 'host', 'temporary image') |
458 |
|
459 |
# Create missing mountpoints. Since they are mountpoints, we
|
460 |
# cannot determine the ownership and the mode of the real
|
461 |
# directory. Make them inherit those properties from their
|
462 |
# parent dir
|
463 |
for excl in excluded: |
464 |
dirname = os.path.dirname(excl) |
465 |
stat = os.stat(dirname) |
466 |
os.mkdir(target + excl) |
467 |
os.chmod(target + excl, stat.st_mode) |
468 |
os.chown(target + excl, stat.st_uid, stat.st_gid) |
469 |
|
470 |
# /tmp and /var/tmp are special cases. We exclude then even if
|
471 |
# they aren't mountpoints. Restore their permissions.
|
472 |
for excl in ('/tmp', '/var/tmp'): |
473 |
if self._is_mpoint(excl): |
474 |
os.chmod(target + excl, 041777)
|
475 |
os.chown(target + excl, 0, 0) |
476 |
else:
|
477 |
stat = os.stat(excl) |
478 |
os.chmod(target + excl, stat.st_mode) |
479 |
os.chown(target + excl, stat.st_uid, stat.st_gid) |
480 |
|
481 |
# We need to replace the old UUID referencies with the new
|
482 |
# ones in grub configuration files and /etc/fstab for file
|
483 |
# systems that have been recreated.
|
484 |
self._replace_uuids(target, new_uuid)
|
485 |
|
486 |
finally:
|
487 |
self._umount_all(target)
|
488 |
os.rmdir(target) |
489 |
finally:
|
490 |
for dev in mapped.values(): |
491 |
self._unmap_partition(dev)
|
492 |
losetup('-d', loop)
|
493 |
|
494 |
def create_image(self, image): |
495 |
"""Given an image filename, this method will create an image out of the
|
496 |
running system.
|
497 |
"""
|
498 |
|
499 |
size = self.disk.device.length * self.disk.device.sectorSize |
500 |
|
501 |
# Create sparse file to host the image
|
502 |
fd = os.open(image, os.O_WRONLY | os.O_CREAT) |
503 |
try:
|
504 |
os.ftruncate(fd, size) |
505 |
finally:
|
506 |
os.close(fd) |
507 |
|
508 |
self._create_partition_table(image)
|
509 |
end_sector, partitions = self._shrink_partitions(image)
|
510 |
|
511 |
if self.disk.type == 'gpt': |
512 |
old_size = size |
513 |
size = (end_sector + 1) * self.disk.device.sectorSize |
514 |
ptable = GPTPartitionTable(image) |
515 |
size = ptable.shrink(size, old_size) |
516 |
else:
|
517 |
# Alighn to 2048
|
518 |
end_sector = ((end_sector + 2047) // 2048) * 2048 |
519 |
size = (end_sector + 1) * self.disk.device.sectorSize |
520 |
|
521 |
# Truncate image to the new size.
|
522 |
fd = os.open(image, os.O_RDWR) |
523 |
try:
|
524 |
os.ftruncate(fd, size) |
525 |
finally:
|
526 |
os.close(fd) |
527 |
|
528 |
# Check if the available space is enough to host the image
|
529 |
dirname = os.path.dirname(image) |
530 |
self.out.output("Examining available space ...", False) |
531 |
if free_space(dirname) <= size:
|
532 |
raise FatalError("Not enough space under %s to host the temporary " |
533 |
"image" % dirname)
|
534 |
self.out.success("sufficient") |
535 |
|
536 |
self._create_filesystems(image, partitions)
|
537 |
|
538 |
return image
|
539 |
|
540 |
# vim: set sta sts=4 shiftwidth=4 sw=4 et ai :
|