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34 from image_creator.util import get_command
35 from image_creator.util import warn, progress, success, output, FatalError
36 from image_creator.gpt import GPTPartitionTable
45 from sendfile import sendfile
48 class DiskError(Exception):
51 dd = get_command('dd')
52 dmsetup = get_command('dmsetup')
53 losetup = get_command('losetup')
54 blockdev = get_command('blockdev')
58 """This class represents a hard disk hosting an Operating System
60 A Disk instance never alters the source media it is created from.
61 Any change is done on a snapshot created by the device-mapper of
65 def __init__(self, source):
66 """Create a new Disk instance out of a source media. The source
67 media can be an image file, a block device or a directory."""
68 self._cleanup_jobs = []
72 def _add_cleanup(self, job, *args):
73 self._cleanup_jobs.append((job, args))
75 def _losetup(self, fname):
76 loop = losetup('-f', '--show', fname)
77 loop = loop.strip() # remove the new-line char
78 self._add_cleanup(losetup, '-d', loop)
81 def _dir_to_disk(self):
82 raise NotImplementedError
85 """Cleanup internal data. This needs to be called before the
88 while len(self._devices):
89 device = self._devices.pop()
92 while len(self._cleanup_jobs):
93 job, args = self._cleanup_jobs.pop()
97 """Creates a snapshot of the original source media of the Disk
101 output("Examining source media `%s'..." % self.source, False)
102 sourcedev = self.source
103 mode = os.stat(self.source).st_mode
104 if stat.S_ISDIR(mode):
105 success('looks like a directory')
106 return self._losetup(self._dir_to_disk())
107 elif stat.S_ISREG(mode):
108 success('looks like an image file')
109 sourcedev = self._losetup(self.source)
110 elif not stat.S_ISBLK(mode):
111 raise ValueError("Invalid media source. Only block devices, "
112 "regular files and directories are supported.")
114 success('looks like a block device')
116 # Take a snapshot and return it to the user
117 output("Snapshotting media source...", False)
118 size = blockdev('--getsize', sourcedev)
119 cowfd, cow = tempfile.mkstemp()
121 self._add_cleanup(os.unlink, cow)
122 # Create 1G cow sparse file
123 dd('if=/dev/null', 'of=%s' % cow, 'bs=1k', 'seek=%d' % (1024 * 1024))
124 cowdev = self._losetup(cow)
126 snapshot = uuid.uuid4().hex
127 tablefd, table = tempfile.mkstemp()
129 os.write(tablefd, "0 %d snapshot %s %s n 8" % \
130 (int(size), sourcedev, cowdev))
131 dmsetup('create', snapshot, table)
132 self._add_cleanup(dmsetup, 'remove', snapshot)
133 # Sometimes dmsetup remove fails with Device or resource busy,
134 # although everything is cleaned up and the snapshot is not
135 # used by anyone. Add a 2 seconds delay to be on the safe side.
136 self._add_cleanup(time.sleep, 2)
141 return "/dev/mapper/%s" % snapshot
143 def get_device(self, media):
144 """Returns a newly created DiskDevice instance."""
146 new_device = DiskDevice(media)
147 self._devices.append(new_device)
151 def destroy_device(self, device):
152 """Destroys a DiskDevice instance previously created by
155 self._devices.remove(device)
159 class DiskDevice(object):
160 """This class represents a block device hosting an Operating System
161 as created by the device-mapper.
164 def __init__(self, device, bootable=True):
165 """Create a new DiskDevice."""
167 self.real_device = device
168 self.bootable = bootable
169 self.progress_bar = None
170 self.guestfs_device = None
173 self.g = guestfs.GuestFS()
174 self.g.add_drive_opts(self.real_device, readonly=0)
177 #self.g.set_verbose(1)
179 self.guestfs_enabled = False
182 """Enable a newly created DiskDevice"""
183 self.progressbar = progress("Launching helper VM: ", "percent")
184 self.progressbar.max = 100
185 self.progressbar.goto(1)
186 eh = self.g.set_event_callback(self.progress_callback,
187 guestfs.EVENT_PROGRESS)
189 self.guestfs_enabled = True
190 self.g.delete_event_callback(eh)
191 if self.progressbar is not None:
192 output("\rLaunching helper VM...\033[K", False)
194 self.progressbar = None
196 output('Inspecting Operating System...', False)
197 roots = self.g.inspect_os()
199 raise FatalError("No operating system found")
201 raise FatalError("Multiple operating systems found."
202 "We only support images with one filesystem.")
204 self.guestfs_device = self.g.part_to_dev(self.root)
205 self.meta['SIZE'] = self.g.blockdev_getsize64(self.guestfs_device)
206 self.meta['PARTITION_TABLE'] = \
207 self.g.part_get_parttype(self.guestfs_device)
209 self.ostype = self.g.inspect_get_type(self.root)
210 self.distro = self.g.inspect_get_distro(self.root)
211 success('found a(n) %s system' % self.distro)
214 """Destroy this DiskDevice instance."""
216 if self.guestfs_enabled:
220 # Close the guestfs handler if open
223 def progress_callback(self, ev, eh, buf, array):
227 self.progressbar.goto((position * 100) // total)
230 """Mount all disk partitions in a correct order."""
232 output("Mounting image...", False)
233 mps = self.g.inspect_get_mountpoints(self.root)
235 # Sort the keys to mount the fs in a correct order.
236 # / should be mounted befor /boot, etc
238 if len(a[0]) > len(b[0]):
240 elif len(a[0]) == len(b[0]):
247 self.g.mount(dev, mp)
248 except RuntimeError as msg:
249 warn("%s (ignored)" % msg)
253 """Umount all mounted filesystems."""
256 def _last_partition(self):
257 if self.meta['PARTITION_TABLE'] not in 'msdos' 'gpt':
258 msg = "Unsupported partition table: %s. Only msdos and gpt " \
259 "partition tables are supported" % self.meta['PARTITION_TABLE']
260 raise FatalError(msg)
262 is_extended = lambda p: self.g.part_get_mbr_id(
263 self.guestfs_device, p['part_num']) == 5
264 is_logical = lambda p: self.meta['PARTITION_TABLE'] != 'msdos' and \
267 partitions = self.g.part_list(self.guestfs_device)
268 last_partition = partitions[-1]
270 if is_logical(last_partition):
271 # The disk contains extended and logical partitions....
272 extended = [p for p in partitions if is_extended(p)][0]
273 last_primary = [p for p in partitions if p['part_num'] <= 4][-1]
275 # check if extended is the last primary partition
276 if last_primary['part_num'] > extended['part_num']:
277 last_partition = last_primary
279 return last_partition
284 This is accomplished by shrinking the last filesystem in the
285 disk and then updating the partition table. The new disk size
286 (in bytes) is returned.
288 ATTENTION: make sure unmount is called before shrink
290 get_fstype = lambda p: self.g.vfs_type("%s%d" % \
291 (self.guestfs_device, p['part_num']))
292 is_logical = lambda p: self.meta['PARTITION_TABLE'] == 'msdos' and \
294 is_extended = lambda p: self.meta['PARTITION_TABLE'] == 'msdos' and \
295 self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) == 5
297 part_add = lambda ptype, start, stop: \
298 self.g.part_add(self.guestfs_device, ptype, start, stop)
299 part_del = lambda p: self.g.part_del(self.guestfs_device, p)
300 part_get_id = lambda p: self.g.part_get_mbr_id(self.guestfs_device, p)
301 part_set_id = lambda p, id: self.g.part_set_mbr_id(
302 self.guestfs_device, p, id)
303 part_get_bootable = lambda p: self.g.part_get_bootable(
304 self.guestfs_device, p)
305 part_set_bootable = lambda p, bootable: self.g.part_set_bootable(
306 self.guestfs_device, p, bootable)
310 output("Shrinking image (this may take a while)...", False)
315 last_part = self._last_partition()
316 fstype = get_fstype(last_part)
319 self.meta['SWAP'] = "%d:%s" % \
320 (last_part['part_num'],
321 (last_part['part_size'] + MB - 1) // MB)
322 part_del(last_part['part_num'])
324 elif is_extended(last_part):
325 part_del(last_part['part_num'])
328 self.meta['SIZE'] = last_part['part_end'] + 1
331 if not re.match("ext[234]", fstype):
332 warn("Don't know how to resize %s partitions." % fstype)
333 return self.meta['SIZE']
335 part_dev = "%s%d" % (self.guestfs_device, last_part['part_num'])
336 self.g.e2fsck_f(part_dev)
337 self.g.resize2fs_M(part_dev)
339 out = self.g.tune2fs_l(part_dev)
341 filter(lambda x: x[0] == 'Block size', out)[0][1])
343 filter(lambda x: x[0] == 'Block count', out)[0][1])
345 sector_size = self.g.blockdev_getss(self.guestfs_device)
346 start = last_part['part_start'] / sector_size
347 end = start + (block_size * block_cnt) / sector_size - 1
349 if is_logical(last_part):
350 partitions = self.g.part_list(self.guestfs_device)
352 logical = [] # logical partitions
353 for partition in partitions:
354 if partition['part_num'] < 4:
357 'num': partition['part_num'],
358 'start': partition['part_start'] / sector_size,
359 'end': partition['part_end'] / sector_size,
360 'id': part_get_(partition['part_num']),
361 'bootable': part_get_bootable(partition['part_num'])
364 logical[-1]['end'] = end # new end after resize
366 # Recreate the extended partition
367 extended = [p for p in partitions if self._is_extended(p)][0]
368 part_del(extended['part_num'])
369 part_add('e', extended['part_start'], end)
371 # Create all the logical partitions back
373 part_add('l', l['start'], l['end'])
374 part_set_id(l['num'], l['id'])
375 part_set_bootable(l['num'], l['bootable'])
377 # Recreate the last partition
378 if self.meta['PARTITION_TABLE'] == 'msdos':
379 last_part['id'] = part_get_id(last_part['part_num'])
381 last_part['bootable'] = part_get_bootable(last_part['part_num'])
382 part_del(last_part['part_num'])
383 part_add('p', start, end)
384 part_set_bootable(last_part['part_num'], last_part['bootable'])
386 if self.meta['PARTITION_TABLE'] == 'msdos':
387 part_set_id(last_part['part_num'], last_part['id'])
389 new_size = (end + 1) * sector_size
390 success("new size is %dMB" % ((new_size + MB - 1) // MB))
392 if self.meta['PARTITION_TABLE'] == 'gpt':
393 ptable = GPTPartitionTable(self.real_device)
394 self.meta['SIZE'] = ptable.shrink(new_size)
396 self.meta['SIZE'] = new_size
398 return self.meta['SIZE']
400 def dump(self, outfile):
401 """Dumps the content of device into a file.
403 This method will only dump the actual payload, found by reading the
404 partition table. Empty space in the end of the device will be ignored.
407 blocksize = 4 * MB # 4MB
408 size = self.meta['SIZE']
409 progress_size = (size + MB - 1) // MB # in MB
410 progressbar = progress("Dumping image file: ", 'mb')
411 progressbar.max = progress_size
413 with open(self.real_device, 'r') as src:
414 with open(outfile, "w") as dst:
419 length = min(left, blocksize)
420 sent = sendfile(dst.fileno(), src.fileno(), offset, length)
423 progressbar.goto((size - left) // MB)
424 output("\rDumping image file...\033[K", False)
425 success('image file %s was successfully created' % outfile)
427 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :