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34 from image_creator.util import get_command
35 from image_creator.util import FatalError
36 from image_creator.gpt import GPTPartitionTable
45 from sendfile import sendfile
48 dd = get_command('dd')
49 dmsetup = get_command('dmsetup')
50 losetup = get_command('losetup')
51 blockdev = get_command('blockdev')
55 """This class represents a hard disk hosting an Operating System
57 A Disk instance never alters the source media it is created from.
58 Any change is done on a snapshot created by the device-mapper of
62 def __init__(self, source, output):
63 """Create a new Disk instance out of a source media. The source
64 media can be an image file, a block device or a directory."""
65 self._cleanup_jobs = []
70 def _add_cleanup(self, job, *args):
71 self._cleanup_jobs.append((job, args))
73 def _losetup(self, fname):
74 loop = losetup('-f', '--show', fname)
75 loop = loop.strip() # remove the new-line char
76 self._add_cleanup(losetup, '-d', loop)
79 def _dir_to_disk(self):
80 raise FatalError("Using a directory as media source is not supported "
84 """Cleanup internal data. This needs to be called before the
87 while len(self._devices):
88 device = self._devices.pop()
91 while len(self._cleanup_jobs):
92 job, args = self._cleanup_jobs.pop()
96 """Creates a snapshot of the original source media of the Disk
100 self.out.output("Examining source media `%s'..." % self.source, False)
101 sourcedev = self.source
102 mode = os.stat(self.source).st_mode
103 if stat.S_ISDIR(mode):
104 self.out.success('looks like a directory')
105 return self._losetup(self._dir_to_disk())
106 elif stat.S_ISREG(mode):
107 self.out.success('looks like an image file')
108 sourcedev = self._losetup(self.source)
109 elif not stat.S_ISBLK(mode):
110 raise ValueError("Invalid media source. Only block devices, "
111 "regular files and directories are supported.")
113 self.out.success('looks like a block device')
115 # Take a snapshot and return it to the user
116 self.out.output("Snapshotting media source...", False)
117 size = blockdev('--getsz', sourcedev)
118 cowfd, cow = tempfile.mkstemp()
120 self._add_cleanup(os.unlink, cow)
121 # Create cow sparse file
122 dd('if=/dev/null', 'of=%s' % cow, 'bs=512', 'seek=%d' % int(size))
123 cowdev = self._losetup(cow)
125 snapshot = uuid.uuid4().hex
126 tablefd, table = tempfile.mkstemp()
128 os.write(tablefd, "0 %d snapshot %s %s n 8" %
129 (int(size), sourcedev, cowdev))
130 dmsetup('create', snapshot, table)
131 self._add_cleanup(dmsetup, 'remove', snapshot)
132 # Sometimes dmsetup remove fails with Device or resource busy,
133 # although everything is cleaned up and the snapshot is not
134 # used by anyone. Add a 2 seconds delay to be on the safe side.
135 self._add_cleanup(time.sleep, 2)
139 self.out.success('done')
140 return "/dev/mapper/%s" % snapshot
142 def get_device(self, media):
143 """Returns a newly created DiskDevice instance."""
145 new_device = DiskDevice(media, self.out)
146 self._devices.append(new_device)
150 def destroy_device(self, device):
151 """Destroys a DiskDevice instance previously created by
154 self._devices.remove(device)
158 class DiskDevice(object):
159 """This class represents a block device hosting an Operating System
160 as created by the device-mapper.
163 def __init__(self, device, output, bootable=True):
164 """Create a new DiskDevice."""
166 self.real_device = device
168 self.bootable = bootable
169 self.progress_bar = None
170 self.guestfs_device = None
174 self.g = guestfs.GuestFS()
175 self.g.add_drive_opts(self.real_device, readonly=0)
177 # Before version 1.17.14 the recovery process, which is a fork of the
178 # original process that called libguestfs, did not close its inherited
179 # file descriptors. This can cause problems especially if the parent
180 # process has opened pipes. Since the recovery process is an optional
181 # feature of libguestfs, it's better to disable it.
182 self.g.set_recovery_proc(0)
183 version = self.g.version()
184 if version['major'] > 1 or \
185 (version['major'] == 1 and (version['minor'] >= 18 or
186 (version['minor'] == 17 and
187 version['release'] >= 14))):
188 self.g.set_recovery_proc(1)
189 self.out.output("Enabling recovery proc")
192 #self.g.set_verbose(1)
194 self.guestfs_enabled = False
197 """Enable a newly created DiskDevice"""
198 self.progressbar = self.out.Progress(100, "Launching helper VM",
200 eh = self.g.set_event_callback(self.progress_callback,
201 guestfs.EVENT_PROGRESS)
203 self.guestfs_enabled = True
204 self.g.delete_event_callback(eh)
205 self.progressbar.success('done')
206 self.progressbar = None
208 self.out.output('Inspecting Operating System...', False)
209 roots = self.g.inspect_os()
211 raise FatalError("No operating system found")
213 raise FatalError("Multiple operating systems found."
214 "We only support images with one OS.")
216 self.guestfs_device = self.g.part_to_dev(self.root)
217 self.size = self.g.blockdev_getsize64(self.guestfs_device)
218 self.meta['PARTITION_TABLE'] = \
219 self.g.part_get_parttype(self.guestfs_device)
221 self.ostype = self.g.inspect_get_type(self.root)
222 self.distro = self.g.inspect_get_distro(self.root)
223 self.out.success('found a(n) %s system' % self.distro)
226 """Destroy this DiskDevice instance."""
228 if self.guestfs_enabled:
232 # Close the guestfs handler if open
235 def progress_callback(self, ev, eh, buf, array):
239 self.progressbar.goto((position * 100) // total)
241 def mount(self, readonly=False):
242 """Mount all disk partitions in a correct order."""
244 mount = self.g.mount_ro if readonly else self.g.mount
245 msg = " read-only" if readonly else ""
246 self.out.output("Mounting the media%s..." % msg, False)
247 mps = self.g.inspect_get_mountpoints(self.root)
249 # Sort the keys to mount the fs in a correct order.
250 # / should be mounted befor /boot, etc
252 if len(a[0]) > len(b[0]):
254 elif len(a[0]) == len(b[0]):
262 except RuntimeError as msg:
263 self.out.warn("%s (ignored)" % msg)
264 self.out.success("done")
267 """Umount all mounted filesystems."""
270 def _last_partition(self):
271 if self.meta['PARTITION_TABLE'] not in 'msdos' 'gpt':
272 msg = "Unsupported partition table: %s. Only msdos and gpt " \
273 "partition tables are supported" % self.meta['PARTITION_TABLE']
274 raise FatalError(msg)
276 is_extended = lambda p: \
277 self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) == 5
278 is_logical = lambda p: \
279 self.meta['PARTITION_TABLE'] != 'msdos' and p['part_num'] > 4
281 partitions = self.g.part_list(self.guestfs_device)
282 last_partition = partitions[-1]
284 if is_logical(last_partition):
285 # The disk contains extended and logical partitions....
286 extended = [p for p in partitions if is_extended(p)][0]
287 last_primary = [p for p in partitions if p['part_num'] <= 4][-1]
289 # check if extended is the last primary partition
290 if last_primary['part_num'] > extended['part_num']:
291 last_partition = last_primary
293 return last_partition
298 This is accomplished by shrinking the last filesystem in the
299 disk and then updating the partition table. The new disk size
300 (in bytes) is returned.
302 ATTENTION: make sure unmount is called before shrink
304 get_fstype = lambda p: \
305 self.g.vfs_type("%s%d" % (self.guestfs_device, p['part_num']))
306 is_logical = lambda p: \
307 self.meta['PARTITION_TABLE'] == 'msdos' and p['part_num'] > 4
308 is_extended = lambda p: \
309 self.meta['PARTITION_TABLE'] == 'msdos' and \
310 self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) == 5
312 part_add = lambda ptype, start, stop: \
313 self.g.part_add(self.guestfs_device, ptype, start, stop)
314 part_del = lambda p: self.g.part_del(self.guestfs_device, p)
315 part_get_id = lambda p: self.g.part_get_mbr_id(self.guestfs_device, p)
316 part_set_id = lambda p, id: \
317 self.g.part_set_mbr_id(self.guestfs_device, p, id)
318 part_get_bootable = lambda p: \
319 self.g.part_get_bootable(self.guestfs_device, p)
320 part_set_bootable = lambda p, bootable: \
321 self.g.part_set_bootable(self.guestfs_device, p, bootable)
325 self.out.output("Shrinking image (this may take a while)...", False)
327 sector_size = self.g.blockdev_getss(self.guestfs_device)
332 last_part = self._last_partition()
333 fstype = get_fstype(last_part)
336 self.meta['SWAP'] = "%d:%s" % \
337 (last_part['part_num'],
338 (last_part['part_size'] + MB - 1) // MB)
339 part_del(last_part['part_num'])
341 elif is_extended(last_part):
342 part_del(last_part['part_num'])
345 # Most disk manipulation programs leave 2048 sectors after the last
347 new_size = last_part['part_end'] + 1 + 2048 * sector_size
348 self.size = min(self.size, new_size)
351 if not re.match("ext[234]", fstype):
352 self.out.warn("Don't know how to resize %s partitions." % fstype)
355 part_dev = "%s%d" % (self.guestfs_device, last_part['part_num'])
356 self.g.e2fsck_f(part_dev)
357 self.g.resize2fs_M(part_dev)
359 out = self.g.tune2fs_l(part_dev)
361 filter(lambda x: x[0] == 'Block size', out)[0][1])
363 filter(lambda x: x[0] == 'Block count', out)[0][1])
365 start = last_part['part_start'] / sector_size
366 end = start + (block_size * block_cnt) / sector_size - 1
368 if is_logical(last_part):
369 partitions = self.g.part_list(self.guestfs_device)
371 logical = [] # logical partitions
372 for partition in partitions:
373 if partition['part_num'] < 4:
376 'num': partition['part_num'],
377 'start': partition['part_start'] / sector_size,
378 'end': partition['part_end'] / sector_size,
379 'id': part_get_(partition['part_num']),
380 'bootable': part_get_bootable(partition['part_num'])
383 logical[-1]['end'] = end # new end after resize
385 # Recreate the extended partition
386 extended = [p for p in partitions if self._is_extended(p)][0]
387 part_del(extended['part_num'])
388 part_add('e', extended['part_start'], end)
390 # Create all the logical partitions back
392 part_add('l', l['start'], l['end'])
393 part_set_id(l['num'], l['id'])
394 part_set_bootable(l['num'], l['bootable'])
396 # Recreate the last partition
397 if self.meta['PARTITION_TABLE'] == 'msdos':
398 last_part['id'] = part_get_id(last_part['part_num'])
400 last_part['bootable'] = part_get_bootable(last_part['part_num'])
401 part_del(last_part['part_num'])
402 part_add('p', start, end)
403 part_set_bootable(last_part['part_num'], last_part['bootable'])
405 if self.meta['PARTITION_TABLE'] == 'msdos':
406 part_set_id(last_part['part_num'], last_part['id'])
408 new_size = (end + 1) * sector_size
410 assert (new_size <= self.size)
412 if self.meta['PARTITION_TABLE'] == 'gpt':
413 ptable = GPTPartitionTable(self.real_device)
414 self.size = ptable.shrink(new_size, self.size)
416 self.size = min(new_size + 2048 * sector_size, self.size)
418 self.out.success("new size is %dMB" % ((self.size + MB - 1) // MB))
422 def dump(self, outfile):
423 """Dumps the content of device into a file.
425 This method will only dump the actual payload, found by reading the
426 partition table. Empty space in the end of the device will be ignored.
429 blocksize = 4 * MB # 4MB
431 progr_size = (size + MB - 1) // MB # in MB
432 progressbar = self.out.Progress(progr_size, "Dumping image file", 'mb')
434 with open(self.real_device, 'r') as src:
435 with open(outfile, "w") as dst:
440 length = min(left, blocksize)
441 sent = sendfile(dst.fileno(), src.fileno(), offset, length)
444 progressbar.goto((size - left) // MB)
445 progressbar.success('image file %s was successfully created' % outfile)
447 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :