root / image_creator / disk.py @ 923d52df
History | View | Annotate | Download (17.1 kB)
1 |
# Copyright 2012 GRNET S.A. All rights reserved.
|
---|---|
2 |
#
|
3 |
# Redistribution and use in source and binary forms, with or
|
4 |
# without modification, are permitted provided that the following
|
5 |
# conditions are met:
|
6 |
#
|
7 |
# 1. Redistributions of source code must retain the above
|
8 |
# copyright notice, this list of conditions and the following
|
9 |
# disclaimer.
|
10 |
#
|
11 |
# 2. Redistributions in binary form must reproduce the above
|
12 |
# copyright notice, this list of conditions and the following
|
13 |
# disclaimer in the documentation and/or other materials
|
14 |
# provided with the distribution.
|
15 |
#
|
16 |
# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
|
17 |
# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
18 |
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
19 |
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
|
20 |
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
21 |
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
22 |
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
|
23 |
# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
24 |
# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
25 |
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
26 |
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
27 |
# POSSIBILITY OF SUCH DAMAGE.
|
28 |
#
|
29 |
# The views and conclusions contained in the software and
|
30 |
# documentation are those of the authors and should not be
|
31 |
# interpreted as representing official policies, either expressed
|
32 |
# or implied, of GRNET S.A.
|
33 |
|
34 |
from image_creator.util import get_command |
35 |
from image_creator.util import FatalError |
36 |
from image_creator.gpt import GPTPartitionTable |
37 |
from image_creator.bundle_volume import BundleVolume |
38 |
|
39 |
import stat |
40 |
import os |
41 |
import tempfile |
42 |
import uuid |
43 |
import re |
44 |
import sys |
45 |
import guestfs |
46 |
import time |
47 |
from sendfile import sendfile |
48 |
|
49 |
|
50 |
dd = get_command('dd')
|
51 |
dmsetup = get_command('dmsetup')
|
52 |
losetup = get_command('losetup')
|
53 |
blockdev = get_command('blockdev')
|
54 |
|
55 |
|
56 |
class Disk(object): |
57 |
"""This class represents a hard disk hosting an Operating System
|
58 |
|
59 |
A Disk instance never alters the source media it is created from.
|
60 |
Any change is done on a snapshot created by the device-mapper of
|
61 |
the Linux kernel.
|
62 |
"""
|
63 |
|
64 |
def __init__(self, source, output): |
65 |
"""Create a new Disk instance out of a source media. The source
|
66 |
media can be an image file, a block device or a directory."""
|
67 |
self._cleanup_jobs = []
|
68 |
self._devices = []
|
69 |
self.source = source
|
70 |
self.out = output
|
71 |
self.meta = {}
|
72 |
|
73 |
def _add_cleanup(self, job, *args): |
74 |
self._cleanup_jobs.append((job, args))
|
75 |
|
76 |
def _losetup(self, fname): |
77 |
loop = losetup('-f', '--show', fname) |
78 |
loop = loop.strip() # remove the new-line char
|
79 |
self._add_cleanup(losetup, '-d', loop) |
80 |
return loop
|
81 |
|
82 |
def _dir_to_disk(self): |
83 |
if self.source == '/': |
84 |
bundle = BundleVolume(self.out, self.meta) |
85 |
image = bundle.create_image() |
86 |
self._add_cleanup(os.unlink, image)
|
87 |
return self._losetup(image) |
88 |
raise FatalError("Using a directory as media source is supported") |
89 |
|
90 |
def cleanup(self): |
91 |
"""Cleanup internal data. This needs to be called before the
|
92 |
program ends.
|
93 |
"""
|
94 |
try:
|
95 |
while len(self._devices): |
96 |
device = self._devices.pop()
|
97 |
device.destroy() |
98 |
finally:
|
99 |
# Make sure those are executed even if one of the device.destroy
|
100 |
# methods throws exeptions.
|
101 |
while len(self._cleanup_jobs): |
102 |
job, args = self._cleanup_jobs.pop()
|
103 |
job(*args) |
104 |
|
105 |
def snapshot(self): |
106 |
"""Creates a snapshot of the original source media of the Disk
|
107 |
instance.
|
108 |
"""
|
109 |
|
110 |
self.out.output("Examining source media `%s'..." % self.source, False) |
111 |
sourcedev = self.source
|
112 |
mode = os.stat(self.source).st_mode
|
113 |
if stat.S_ISDIR(mode):
|
114 |
self.out.success('looks like a directory') |
115 |
return self._dir_to_disk() |
116 |
elif stat.S_ISREG(mode):
|
117 |
self.out.success('looks like an image file') |
118 |
sourcedev = self._losetup(self.source) |
119 |
elif not stat.S_ISBLK(mode): |
120 |
raise ValueError("Invalid media source. Only block devices, " |
121 |
"regular files and directories are supported.")
|
122 |
else:
|
123 |
self.out.success('looks like a block device') |
124 |
|
125 |
# Take a snapshot and return it to the user
|
126 |
self.out.output("Snapshotting media source...", False) |
127 |
size = blockdev('--getsz', sourcedev)
|
128 |
cowfd, cow = tempfile.mkstemp() |
129 |
os.close(cowfd) |
130 |
self._add_cleanup(os.unlink, cow)
|
131 |
# Create cow sparse file
|
132 |
dd('if=/dev/null', 'of=%s' % cow, 'bs=512', 'seek=%d' % int(size)) |
133 |
cowdev = self._losetup(cow)
|
134 |
|
135 |
snapshot = uuid.uuid4().hex |
136 |
tablefd, table = tempfile.mkstemp() |
137 |
try:
|
138 |
os.write(tablefd, "0 %d snapshot %s %s n 8" %
|
139 |
(int(size), sourcedev, cowdev))
|
140 |
dmsetup('create', snapshot, table)
|
141 |
self._add_cleanup(dmsetup, 'remove', snapshot) |
142 |
# Sometimes dmsetup remove fails with Device or resource busy,
|
143 |
# although everything is cleaned up and the snapshot is not
|
144 |
# used by anyone. Add a 2 seconds delay to be on the safe side.
|
145 |
self._add_cleanup(time.sleep, 2) |
146 |
|
147 |
finally:
|
148 |
os.unlink(table) |
149 |
self.out.success('done') |
150 |
return "/dev/mapper/%s" % snapshot |
151 |
|
152 |
def get_device(self, media): |
153 |
"""Returns a newly created DiskDevice instance."""
|
154 |
|
155 |
new_device = DiskDevice(media, self.out)
|
156 |
self._devices.append(new_device)
|
157 |
new_device.enable() |
158 |
return new_device
|
159 |
|
160 |
def destroy_device(self, device): |
161 |
"""Destroys a DiskDevice instance previously created by
|
162 |
get_device method.
|
163 |
"""
|
164 |
self._devices.remove(device)
|
165 |
device.destroy() |
166 |
|
167 |
|
168 |
class DiskDevice(object): |
169 |
"""This class represents a block device hosting an Operating System
|
170 |
as created by the device-mapper.
|
171 |
"""
|
172 |
|
173 |
def __init__(self, device, output, bootable=True, meta={}): |
174 |
"""Create a new DiskDevice."""
|
175 |
|
176 |
self.real_device = device
|
177 |
self.out = output
|
178 |
self.bootable = bootable
|
179 |
self.meta = meta
|
180 |
self.progress_bar = None |
181 |
self.guestfs_device = None |
182 |
self.size = 0 |
183 |
|
184 |
self.g = guestfs.GuestFS()
|
185 |
self.g.add_drive_opts(self.real_device, readonly=0) |
186 |
|
187 |
# Before version 1.17.14 the recovery process, which is a fork of the
|
188 |
# original process that called libguestfs, did not close its inherited
|
189 |
# file descriptors. This can cause problems especially if the parent
|
190 |
# process has opened pipes. Since the recovery process is an optional
|
191 |
# feature of libguestfs, it's better to disable it.
|
192 |
self.g.set_recovery_proc(0) |
193 |
version = self.g.version()
|
194 |
if version['major'] > 1 or \ |
195 |
(version['major'] == 1 and (version['minor'] >= 18 or |
196 |
(version['minor'] == 17 and |
197 |
version['release'] >= 14))): |
198 |
self.g.set_recovery_proc(1) |
199 |
self.out.output("Enabling recovery proc") |
200 |
|
201 |
#self.g.set_trace(1)
|
202 |
#self.g.set_verbose(1)
|
203 |
|
204 |
self.guestfs_enabled = False |
205 |
|
206 |
def enable(self): |
207 |
"""Enable a newly created DiskDevice"""
|
208 |
|
209 |
self.out.output('Launching helper VM (may take a while) ...', False) |
210 |
# self.progressbar = self.out.Progress(100, "Launching helper VM",
|
211 |
# "percent")
|
212 |
# eh = self.g.set_event_callback(self.progress_callback,
|
213 |
# guestfs.EVENT_PROGRESS)
|
214 |
self.g.launch()
|
215 |
self.guestfs_enabled = True |
216 |
# self.g.delete_event_callback(eh)
|
217 |
# self.progressbar.success('done')
|
218 |
# self.progressbar = None
|
219 |
self.out.success('done') |
220 |
|
221 |
self.out.output('Inspecting Operating System ...', False) |
222 |
roots = self.g.inspect_os()
|
223 |
if len(roots) == 0: |
224 |
raise FatalError("No operating system found") |
225 |
if len(roots) > 1: |
226 |
raise FatalError("Multiple operating systems found." |
227 |
"We only support images with one OS.")
|
228 |
self.root = roots[0] |
229 |
self.guestfs_device = self.g.part_to_dev(self.root) |
230 |
self.size = self.g.blockdev_getsize64(self.guestfs_device) |
231 |
self.meta['PARTITION_TABLE'] = \ |
232 |
self.g.part_get_parttype(self.guestfs_device) |
233 |
|
234 |
self.ostype = self.g.inspect_get_type(self.root) |
235 |
self.distro = self.g.inspect_get_distro(self.root) |
236 |
self.out.success('found a(n) %s system' % self.distro) |
237 |
|
238 |
def destroy(self): |
239 |
"""Destroy this DiskDevice instance."""
|
240 |
|
241 |
# In new guestfs versions, there is a handy shutdown method for this
|
242 |
try:
|
243 |
if self.guestfs_enabled: |
244 |
self.g.umount_all()
|
245 |
self.g.sync()
|
246 |
finally:
|
247 |
# Close the guestfs handler if open
|
248 |
self.g.close()
|
249 |
|
250 |
# def progress_callback(self, ev, eh, buf, array):
|
251 |
# position = array[2]
|
252 |
# total = array[3]
|
253 |
#
|
254 |
# self.progressbar.goto((position * 100) // total)
|
255 |
|
256 |
def mount(self, readonly=False): |
257 |
"""Mount all disk partitions in a correct order."""
|
258 |
|
259 |
mount = self.g.mount_ro if readonly else self.g.mount |
260 |
msg = " read-only" if readonly else "" |
261 |
self.out.output("Mounting the media%s..." % msg, False) |
262 |
mps = self.g.inspect_get_mountpoints(self.root) |
263 |
|
264 |
# Sort the keys to mount the fs in a correct order.
|
265 |
# / should be mounted befor /boot, etc
|
266 |
def compare(a, b): |
267 |
if len(a[0]) > len(b[0]): |
268 |
return 1 |
269 |
elif len(a[0]) == len(b[0]): |
270 |
return 0 |
271 |
else:
|
272 |
return -1 |
273 |
mps.sort(compare) |
274 |
for mp, dev in mps: |
275 |
try:
|
276 |
mount(dev, mp) |
277 |
except RuntimeError as msg: |
278 |
self.out.warn("%s (ignored)" % msg) |
279 |
self.out.success("done") |
280 |
|
281 |
def umount(self): |
282 |
"""Umount all mounted filesystems."""
|
283 |
self.g.umount_all()
|
284 |
|
285 |
def _last_partition(self): |
286 |
if self.meta['PARTITION_TABLE'] not in 'msdos' 'gpt': |
287 |
msg = "Unsupported partition table: %s. Only msdos and gpt " \
|
288 |
"partition tables are supported" % self.meta['PARTITION_TABLE'] |
289 |
raise FatalError(msg)
|
290 |
|
291 |
is_extended = lambda p: \
|
292 |
self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) == 5 |
293 |
is_logical = lambda p: \
|
294 |
self.meta['PARTITION_TABLE'] != 'msdos' and p['part_num'] > 4 |
295 |
|
296 |
partitions = self.g.part_list(self.guestfs_device) |
297 |
last_partition = partitions[-1]
|
298 |
|
299 |
if is_logical(last_partition):
|
300 |
# The disk contains extended and logical partitions....
|
301 |
extended = [p for p in partitions if is_extended(p)][0] |
302 |
last_primary = [p for p in partitions if p['part_num'] <= 4][-1] |
303 |
|
304 |
# check if extended is the last primary partition
|
305 |
if last_primary['part_num'] > extended['part_num']: |
306 |
last_partition = last_primary |
307 |
|
308 |
return last_partition
|
309 |
|
310 |
def shrink(self): |
311 |
"""Shrink the disk.
|
312 |
|
313 |
This is accomplished by shrinking the last filesystem in the
|
314 |
disk and then updating the partition table. The new disk size
|
315 |
(in bytes) is returned.
|
316 |
|
317 |
ATTENTION: make sure unmount is called before shrink
|
318 |
"""
|
319 |
get_fstype = lambda p: \
|
320 |
self.g.vfs_type("%s%d" % (self.guestfs_device, p['part_num'])) |
321 |
is_logical = lambda p: \
|
322 |
self.meta['PARTITION_TABLE'] == 'msdos' and p['part_num'] > 4 |
323 |
is_extended = lambda p: \
|
324 |
self.meta['PARTITION_TABLE'] == 'msdos' and \ |
325 |
self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) == 5 |
326 |
|
327 |
part_add = lambda ptype, start, stop: \
|
328 |
self.g.part_add(self.guestfs_device, ptype, start, stop) |
329 |
part_del = lambda p: self.g.part_del(self.guestfs_device, p) |
330 |
part_get_id = lambda p: self.g.part_get_mbr_id(self.guestfs_device, p) |
331 |
part_set_id = lambda p, id: \ |
332 |
self.g.part_set_mbr_id(self.guestfs_device, p, id) |
333 |
part_get_bootable = lambda p: \
|
334 |
self.g.part_get_bootable(self.guestfs_device, p) |
335 |
part_set_bootable = lambda p, bootable: \
|
336 |
self.g.part_set_bootable(self.guestfs_device, p, bootable) |
337 |
|
338 |
MB = 2 ** 20 |
339 |
|
340 |
self.out.output("Shrinking image (this may take a while)...", False) |
341 |
|
342 |
sector_size = self.g.blockdev_getss(self.guestfs_device) |
343 |
|
344 |
last_part = None
|
345 |
fstype = None
|
346 |
while True: |
347 |
last_part = self._last_partition()
|
348 |
fstype = get_fstype(last_part) |
349 |
|
350 |
if fstype == 'swap': |
351 |
self.meta['SWAP'] = "%d:%s" % \ |
352 |
(last_part['part_num'],
|
353 |
(last_part['part_size'] + MB - 1) // MB) |
354 |
part_del(last_part['part_num'])
|
355 |
continue
|
356 |
elif is_extended(last_part):
|
357 |
part_del(last_part['part_num'])
|
358 |
continue
|
359 |
|
360 |
# Most disk manipulation programs leave 2048 sectors after the last
|
361 |
# partition
|
362 |
new_size = last_part['part_end'] + 1 + 2048 * sector_size |
363 |
self.size = min(self.size, new_size) |
364 |
break
|
365 |
|
366 |
if not re.match("ext[234]", fstype): |
367 |
self.out.warn("Don't know how to resize %s partitions." % fstype) |
368 |
return self.size |
369 |
|
370 |
part_dev = "%s%d" % (self.guestfs_device, last_part['part_num']) |
371 |
self.g.e2fsck_f(part_dev)
|
372 |
self.g.resize2fs_M(part_dev)
|
373 |
|
374 |
out = self.g.tune2fs_l(part_dev)
|
375 |
block_size = int(
|
376 |
filter(lambda x: x[0] == 'Block size', out)[0][1]) |
377 |
block_cnt = int(
|
378 |
filter(lambda x: x[0] == 'Block count', out)[0][1]) |
379 |
|
380 |
start = last_part['part_start'] / sector_size
|
381 |
end = start + (block_size * block_cnt) / sector_size - 1
|
382 |
|
383 |
if is_logical(last_part):
|
384 |
partitions = self.g.part_list(self.guestfs_device) |
385 |
|
386 |
logical = [] # logical partitions
|
387 |
for partition in partitions: |
388 |
if partition['part_num'] < 4: |
389 |
continue
|
390 |
logical.append({ |
391 |
'num': partition['part_num'], |
392 |
'start': partition['part_start'] / sector_size, |
393 |
'end': partition['part_end'] / sector_size, |
394 |
'id': part_get_(partition['part_num']), |
395 |
'bootable': part_get_bootable(partition['part_num']) |
396 |
}) |
397 |
|
398 |
logical[-1]['end'] = end # new end after resize |
399 |
|
400 |
# Recreate the extended partition
|
401 |
extended = [p for p in partitions if self._is_extended(p)][0] |
402 |
part_del(extended['part_num'])
|
403 |
part_add('e', extended['part_start'], end) |
404 |
|
405 |
# Create all the logical partitions back
|
406 |
for l in logical: |
407 |
part_add('l', l['start'], l['end']) |
408 |
part_set_id(l['num'], l['id']) |
409 |
part_set_bootable(l['num'], l['bootable']) |
410 |
else:
|
411 |
# Recreate the last partition
|
412 |
if self.meta['PARTITION_TABLE'] == 'msdos': |
413 |
last_part['id'] = part_get_id(last_part['part_num']) |
414 |
|
415 |
last_part['bootable'] = part_get_bootable(last_part['part_num']) |
416 |
part_del(last_part['part_num'])
|
417 |
part_add('p', start, end)
|
418 |
part_set_bootable(last_part['part_num'], last_part['bootable']) |
419 |
|
420 |
if self.meta['PARTITION_TABLE'] == 'msdos': |
421 |
part_set_id(last_part['part_num'], last_part['id']) |
422 |
|
423 |
new_size = (end + 1) * sector_size
|
424 |
|
425 |
assert (new_size <= self.size) |
426 |
|
427 |
if self.meta['PARTITION_TABLE'] == 'gpt': |
428 |
ptable = GPTPartitionTable(self.real_device)
|
429 |
self.size = ptable.shrink(new_size, self.size) |
430 |
else:
|
431 |
self.size = min(new_size + 2048 * sector_size, self.size) |
432 |
|
433 |
self.out.success("new size is %dMB" % ((self.size + MB - 1) // MB)) |
434 |
|
435 |
return self.size |
436 |
|
437 |
def dump(self, outfile): |
438 |
"""Dumps the content of device into a file.
|
439 |
|
440 |
This method will only dump the actual payload, found by reading the
|
441 |
partition table. Empty space in the end of the device will be ignored.
|
442 |
"""
|
443 |
MB = 2 ** 20 |
444 |
blocksize = 4 * MB # 4MB |
445 |
size = self.size
|
446 |
progr_size = (size + MB - 1) // MB # in MB |
447 |
progressbar = self.out.Progress(progr_size, "Dumping image file", 'mb') |
448 |
|
449 |
with open(self.real_device, 'r') as src: |
450 |
with open(outfile, "w") as dst: |
451 |
left = size |
452 |
offset = 0
|
453 |
progressbar.next() |
454 |
while left > 0: |
455 |
length = min(left, blocksize)
|
456 |
_, sent = sendfile(dst.fileno(), src.fileno(), offset, |
457 |
length) |
458 |
offset += sent |
459 |
left -= sent |
460 |
progressbar.goto((size - left) // MB) |
461 |
progressbar.success('image file %s was successfully created' % outfile)
|
462 |
|
463 |
# vim: set sta sts=4 shiftwidth=4 sw=4 et ai :
|