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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 self.out.output("Mounting image...", False)
246 mps = self.g.inspect_get_mountpoints(self.root)
248 # Sort the keys to mount the fs in a correct order.
249 # / should be mounted befor /boot, etc
251 if len(a[0]) > len(b[0]):
253 elif len(a[0]) == len(b[0]):
261 except RuntimeError as msg:
262 self.out.warn("%s (ignored)" % msg)
263 self.out.success("done")
266 """Umount all mounted filesystems."""
269 def _last_partition(self):
270 if self.meta['PARTITION_TABLE'] not in 'msdos' 'gpt':
271 msg = "Unsupported partition table: %s. Only msdos and gpt " \
272 "partition tables are supported" % self.meta['PARTITION_TABLE']
273 raise FatalError(msg)
275 is_extended = lambda p: \
276 self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) == 5
277 is_logical = lambda p: \
278 self.meta['PARTITION_TABLE'] != 'msdos' and p['part_num'] > 4
280 partitions = self.g.part_list(self.guestfs_device)
281 last_partition = partitions[-1]
283 if is_logical(last_partition):
284 # The disk contains extended and logical partitions....
285 extended = [p for p in partitions if is_extended(p)][0]
286 last_primary = [p for p in partitions if p['part_num'] <= 4][-1]
288 # check if extended is the last primary partition
289 if last_primary['part_num'] > extended['part_num']:
290 last_partition = last_primary
292 return last_partition
297 This is accomplished by shrinking the last filesystem in the
298 disk and then updating the partition table. The new disk size
299 (in bytes) is returned.
301 ATTENTION: make sure unmount is called before shrink
303 get_fstype = lambda p: \
304 self.g.vfs_type("%s%d" % (self.guestfs_device, p['part_num']))
305 is_logical = lambda p: \
306 self.meta['PARTITION_TABLE'] == 'msdos' and p['part_num'] > 4
307 is_extended = lambda p: \
308 self.meta['PARTITION_TABLE'] == 'msdos' and \
309 self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) == 5
311 part_add = lambda ptype, start, stop: \
312 self.g.part_add(self.guestfs_device, ptype, start, stop)
313 part_del = lambda p: self.g.part_del(self.guestfs_device, p)
314 part_get_id = lambda p: self.g.part_get_mbr_id(self.guestfs_device, p)
315 part_set_id = lambda p, id: \
316 self.g.part_set_mbr_id(self.guestfs_device, p, id)
317 part_get_bootable = lambda p: \
318 self.g.part_get_bootable(self.guestfs_device, p)
319 part_set_bootable = lambda p, bootable: \
320 self.g.part_set_bootable(self.guestfs_device, p, bootable)
324 self.out.output("Shrinking image (this may take a while)...", False)
326 sector_size = self.g.blockdev_getss(self.guestfs_device)
331 last_part = self._last_partition()
332 fstype = get_fstype(last_part)
335 self.meta['SWAP'] = "%d:%s" % \
336 (last_part['part_num'],
337 (last_part['part_size'] + MB - 1) // MB)
338 part_del(last_part['part_num'])
340 elif is_extended(last_part):
341 part_del(last_part['part_num'])
344 # Most disk manipulation programs leave 2048 sectors after the last
346 new_size = last_part['part_end'] + 1 + 2048 * sector_size
347 self.size = min(self.size, new_size)
350 if not re.match("ext[234]", fstype):
351 self.out.warn("Don't know how to resize %s partitions." % fstype)
354 part_dev = "%s%d" % (self.guestfs_device, last_part['part_num'])
355 self.g.e2fsck_f(part_dev)
356 self.g.resize2fs_M(part_dev)
358 out = self.g.tune2fs_l(part_dev)
360 filter(lambda x: x[0] == 'Block size', out)[0][1])
362 filter(lambda x: x[0] == 'Block count', out)[0][1])
364 start = last_part['part_start'] / sector_size
365 end = start + (block_size * block_cnt) / sector_size - 1
367 if is_logical(last_part):
368 partitions = self.g.part_list(self.guestfs_device)
370 logical = [] # logical partitions
371 for partition in partitions:
372 if partition['part_num'] < 4:
375 'num': partition['part_num'],
376 'start': partition['part_start'] / sector_size,
377 'end': partition['part_end'] / sector_size,
378 'id': part_get_(partition['part_num']),
379 'bootable': part_get_bootable(partition['part_num'])
382 logical[-1]['end'] = end # new end after resize
384 # Recreate the extended partition
385 extended = [p for p in partitions if self._is_extended(p)][0]
386 part_del(extended['part_num'])
387 part_add('e', extended['part_start'], end)
389 # Create all the logical partitions back
391 part_add('l', l['start'], l['end'])
392 part_set_id(l['num'], l['id'])
393 part_set_bootable(l['num'], l['bootable'])
395 # Recreate the last partition
396 if self.meta['PARTITION_TABLE'] == 'msdos':
397 last_part['id'] = part_get_id(last_part['part_num'])
399 last_part['bootable'] = part_get_bootable(last_part['part_num'])
400 part_del(last_part['part_num'])
401 part_add('p', start, end)
402 part_set_bootable(last_part['part_num'], last_part['bootable'])
404 if self.meta['PARTITION_TABLE'] == 'msdos':
405 part_set_id(last_part['part_num'], last_part['id'])
407 new_size = (end + 1) * sector_size
409 assert (new_size <= self.size)
411 if self.meta['PARTITION_TABLE'] == 'gpt':
412 ptable = GPTPartitionTable(self.real_device)
413 self.size = ptable.shrink(new_size, self.size)
415 self.size = min(new_size + 2048 * sector_size, self.size)
417 self.out.success("new size is %dMB" % ((self.size + MB - 1) // MB))
421 def dump(self, outfile):
422 """Dumps the content of device into a file.
424 This method will only dump the actual payload, found by reading the
425 partition table. Empty space in the end of the device will be ignored.
428 blocksize = 4 * MB # 4MB
430 progr_size = (size + MB - 1) // MB # in MB
431 progressbar = self.out.Progress(progr_size, "Dumping image file", 'mb')
433 with open(self.real_device, 'r') as src:
434 with open(outfile, "w") as dst:
439 length = min(left, blocksize)
440 sent = sendfile(dst.fileno(), src.fileno(), offset, length)
443 progressbar.goto((size - left) // MB)
444 progressbar.success('image file %s was successfully created' % outfile)
446 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :