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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('--getsize', sourcedev)
118 cowfd, cow = tempfile.mkstemp()
120 self._add_cleanup(os.unlink, cow)
121 # Create 1G cow sparse file
122 dd('if=/dev/null', 'of=%s' % cow, 'bs=1k', 'seek=%d' % (1024 * 1024))
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
173 self.g = guestfs.GuestFS()
174 self.g.add_drive_opts(self.real_device, readonly=0)
176 # Before version 1.17.14 the recovery process, which is a fork of the
177 # original process that called libguestfs, did not close its inherited
178 # file descriptors. This can cause problems especially if the parent
179 # process has opened pipes. Since the recovery process is an optional
180 # feature of libguestfs, it's better to disable it.
181 self.g.set_recovery_proc(0)
182 version = self.g.version()
183 if version['major'] > 1 or (version['major'] == 1 and
184 (version['minor'] >= 18 or \
185 (version['minor'] == 17 and version['release'] >= 14))):
186 self.g.set_recovery_proc(1)
187 self.out.output("Enabling recovery proc")
190 #self.g.set_verbose(1)
192 self.guestfs_enabled = False
195 """Enable a newly created DiskDevice"""
196 self.progressbar = self.out.Progress(100, "Launching helper VM",
198 eh = self.g.set_event_callback(self.progress_callback,
199 guestfs.EVENT_PROGRESS)
201 self.guestfs_enabled = True
202 self.g.delete_event_callback(eh)
203 self.progressbar.success('done')
204 self.progressbar = None
206 self.out.output('Inspecting Operating System...', False)
207 roots = self.g.inspect_os()
209 raise FatalError("No operating system found")
211 raise FatalError("Multiple operating systems found."
212 "We only support images with one filesystem.")
214 self.guestfs_device = self.g.part_to_dev(self.root)
215 self.meta['SIZE'] = self.g.blockdev_getsize64(self.guestfs_device)
216 self.meta['PARTITION_TABLE'] = \
217 self.g.part_get_parttype(self.guestfs_device)
219 self.ostype = self.g.inspect_get_type(self.root)
220 self.distro = self.g.inspect_get_distro(self.root)
221 self.out.success('found a(n) %s system' % self.distro)
224 """Destroy this DiskDevice instance."""
226 if self.guestfs_enabled:
230 # Close the guestfs handler if open
233 def progress_callback(self, ev, eh, buf, array):
237 self.progressbar.goto((position * 100) // total)
239 def mount(self, readonly=False):
240 """Mount all disk partitions in a correct order."""
242 mount = self.g.mount_ro if readonly else self.g.mount
243 self.out.output("Mounting image...", False)
244 mps = self.g.inspect_get_mountpoints(self.root)
246 # Sort the keys to mount the fs in a correct order.
247 # / should be mounted befor /boot, etc
249 if len(a[0]) > len(b[0]):
251 elif len(a[0]) == len(b[0]):
259 except RuntimeError as msg:
260 self.out.warn("%s (ignored)" % msg)
261 self.out.success("done")
264 """Umount all mounted filesystems."""
267 def _last_partition(self):
268 if self.meta['PARTITION_TABLE'] not in 'msdos' 'gpt':
269 msg = "Unsupported partition table: %s. Only msdos and gpt " \
270 "partition tables are supported" % self.meta['PARTITION_TABLE']
271 raise FatalError(msg)
273 is_extended = lambda p: self.g.part_get_mbr_id(
274 self.guestfs_device, p['part_num']) == 5
275 is_logical = lambda p: self.meta['PARTITION_TABLE'] != 'msdos' and \
278 partitions = self.g.part_list(self.guestfs_device)
279 last_partition = partitions[-1]
281 if is_logical(last_partition):
282 # The disk contains extended and logical partitions....
283 extended = [p for p in partitions if is_extended(p)][0]
284 last_primary = [p for p in partitions if p['part_num'] <= 4][-1]
286 # check if extended is the last primary partition
287 if last_primary['part_num'] > extended['part_num']:
288 last_partition = last_primary
290 return last_partition
295 This is accomplished by shrinking the last filesystem in the
296 disk and then updating the partition table. The new disk size
297 (in bytes) is returned.
299 ATTENTION: make sure unmount is called before shrink
301 get_fstype = lambda p: self.g.vfs_type("%s%d" % \
302 (self.guestfs_device, p['part_num']))
303 is_logical = lambda p: self.meta['PARTITION_TABLE'] == 'msdos' and \
305 is_extended = lambda p: self.meta['PARTITION_TABLE'] == 'msdos' and \
306 self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) == 5
308 part_add = lambda ptype, start, stop: \
309 self.g.part_add(self.guestfs_device, ptype, start, stop)
310 part_del = lambda p: self.g.part_del(self.guestfs_device, p)
311 part_get_id = lambda p: self.g.part_get_mbr_id(self.guestfs_device, p)
312 part_set_id = lambda p, id: self.g.part_set_mbr_id(
313 self.guestfs_device, p, id)
314 part_get_bootable = lambda p: self.g.part_get_bootable(
315 self.guestfs_device, p)
316 part_set_bootable = lambda p, bootable: self.g.part_set_bootable(
317 self.guestfs_device, p, bootable)
321 self.out.output("Shrinking image (this may take a while)...", False)
326 last_part = self._last_partition()
327 fstype = get_fstype(last_part)
330 self.meta['SWAP'] = "%d:%s" % \
331 (last_part['part_num'],
332 (last_part['part_size'] + MB - 1) // MB)
333 part_del(last_part['part_num'])
335 elif is_extended(last_part):
336 part_del(last_part['part_num'])
339 self.meta['SIZE'] = last_part['part_end'] + 1
342 if not re.match("ext[234]", fstype):
343 self.out.warn("Don't know how to resize %s partitions." % fstype)
344 return self.meta['SIZE']
346 part_dev = "%s%d" % (self.guestfs_device, last_part['part_num'])
347 self.g.e2fsck_f(part_dev)
348 self.g.resize2fs_M(part_dev)
350 out = self.g.tune2fs_l(part_dev)
352 filter(lambda x: x[0] == 'Block size', out)[0][1])
354 filter(lambda x: x[0] == 'Block count', out)[0][1])
356 sector_size = self.g.blockdev_getss(self.guestfs_device)
357 start = last_part['part_start'] / sector_size
358 end = start + (block_size * block_cnt) / sector_size - 1
360 if is_logical(last_part):
361 partitions = self.g.part_list(self.guestfs_device)
363 logical = [] # logical partitions
364 for partition in partitions:
365 if partition['part_num'] < 4:
368 'num': partition['part_num'],
369 'start': partition['part_start'] / sector_size,
370 'end': partition['part_end'] / sector_size,
371 'id': part_get_(partition['part_num']),
372 'bootable': part_get_bootable(partition['part_num'])
375 logical[-1]['end'] = end # new end after resize
377 # Recreate the extended partition
378 extended = [p for p in partitions if self._is_extended(p)][0]
379 part_del(extended['part_num'])
380 part_add('e', extended['part_start'], end)
382 # Create all the logical partitions back
384 part_add('l', l['start'], l['end'])
385 part_set_id(l['num'], l['id'])
386 part_set_bootable(l['num'], l['bootable'])
388 # Recreate the last partition
389 if self.meta['PARTITION_TABLE'] == 'msdos':
390 last_part['id'] = part_get_id(last_part['part_num'])
392 last_part['bootable'] = part_get_bootable(last_part['part_num'])
393 part_del(last_part['part_num'])
394 part_add('p', start, end)
395 part_set_bootable(last_part['part_num'], last_part['bootable'])
397 if self.meta['PARTITION_TABLE'] == 'msdos':
398 part_set_id(last_part['part_num'], last_part['id'])
400 new_size = (end + 1) * sector_size
401 self.out.success("new size is %dMB" % ((new_size + MB - 1) // MB))
403 if self.meta['PARTITION_TABLE'] == 'gpt':
404 ptable = GPTPartitionTable(self.real_device)
405 self.meta['SIZE'] = ptable.shrink(new_size)
407 self.meta['SIZE'] = new_size
409 return self.meta['SIZE']
411 def dump(self, outfile):
412 """Dumps the content of device into a file.
414 This method will only dump the actual payload, found by reading the
415 partition table. Empty space in the end of the device will be ignored.
418 blocksize = 4 * MB # 4MB
419 size = self.meta['SIZE']
420 progr_size = (size + MB - 1) // MB # in MB
421 progressbar = self.out.Progress(progr_size, "Dumping image file", 'mb')
423 with open(self.real_device, 'r') as src:
424 with open(outfile, "w") as dst:
429 length = min(left, blocksize)
430 sent = sendfile(dst.fileno(), src.fileno(), offset, length)
433 progressbar.goto((size - left) // MB)
434 progressbar.success('image file %s was successfully created' % outfile)
436 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :