1 # Copyright 2012 GRNET S.A. All rights reserved.
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4 # without modification, are permitted provided that the following
7 # 1. Redistributions of source code must retain the above
8 # copyright notice, this list of conditions and the following
11 # 2. Redistributions in binary form must reproduce the above
12 # copyright notice, this list of conditions and the following
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34 from image_creator.util import get_command
35 from image_creator.util import warn, progress, success, output, FatalError
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', \
124 'seek=%d' % (1024 * 1024))
125 cowdev = self._losetup(cow)
127 snapshot = uuid.uuid4().hex
128 tablefd, table = tempfile.mkstemp()
130 os.write(tablefd, "0 %d snapshot %s %s n 8" % \
131 (int(size), sourcedev, cowdev))
132 dmsetup('create', snapshot, table)
133 self._add_cleanup(dmsetup, 'remove', snapshot)
134 # Sometimes dmsetup remove fails with Device or resource busy,
135 # although everything is cleaned up and the snapshot is not
136 # used by anyone. Add a 2 seconds delay to be on the safe side.
137 self._add_cleanup(time.sleep, 2)
142 return "/dev/mapper/%s" % snapshot
144 def get_device(self, media):
145 """Returns a newly created DiskDevice instance."""
147 new_device = DiskDevice(media)
148 self._devices.append(new_device)
152 def destroy_device(self, device):
153 """Destroys a DiskDevice instance previously created by
156 self._devices.remove(device)
160 class DiskDevice(object):
161 """This class represents a block device hosting an Operating System
162 as created by the device-mapper.
165 def __init__(self, device, bootable=True):
166 """Create a new DiskDevice."""
169 self.bootable = bootable
170 self.progress_bar = None
172 self.g = guestfs.GuestFS()
173 self.g.add_drive_opts(self.device, readonly=0)
176 #self.g.set_verbose(1)
178 self.guestfs_enabled = False
181 """Enable a newly created DiskDevice"""
182 self.progressbar = progress("Launching helper VM: ")
183 self.progressbar.next()
184 eh = self.g.set_event_callback(self.progress_callback,
185 guestfs.EVENT_PROGRESS)
187 self.guestfs_enabled = True
188 self.g.delete_event_callback(eh)
189 if self.progressbar is not None:
190 self.progressbar.send(100)
191 self.progressbar = None
193 output('Inspecting Operating System...', False)
194 roots = self.g.inspect_os()
196 raise FatalError("No operating system found")
198 raise FatalError("Multiple operating systems found."
199 "We only support images with one filesystem.")
201 self.ostype = self.g.inspect_get_type(self.root)
202 self.distro = self.g.inspect_get_distro(self.root)
203 success('found a %s system' % self.distro)
206 """Destroy this DiskDevice instance."""
208 if self.guestfs_enabled:
212 # Close the guestfs handler if open
215 def progress_callback(self, ev, eh, buf, array):
219 self.progressbar.send((position * 100) // total)
221 if position == total:
222 self.progressbar = None
225 """Mount all disk partitions in a correct order."""
227 output("Mounting image...", False)
228 mps = self.g.inspect_get_mountpoints(self.root)
230 # Sort the keys to mount the fs in a correct order.
231 # / should be mounted befor /boot, etc
233 if len(a[0]) > len(b[0]):
235 elif len(a[0]) == len(b[0]):
242 self.g.mount(dev, mp)
243 except RuntimeError as msg:
244 warn("%s (ignored)" % msg)
248 """Umount all mounted filesystems."""
254 This is accomplished by shrinking the last filesystem in the
255 disk and then updating the partition table. The new disk size
256 (in bytes) is returned.
258 output("Shrinking image (this may take a while)...", False)
260 dev = self.g.part_to_dev(self.root)
261 parttype = self.g.part_get_parttype(dev)
262 if parttype != 'msdos':
263 raise FatalError("You have a %s partition table. "
264 "Only msdos partitions are supported" % parttype)
266 last_partition = self.g.part_list(dev)[-1]
268 if last_partition['part_num'] > 4:
269 raise FatalError("This disk contains logical partitions. "
270 "Only primary partitions are supported.")
272 part_dev = "%s%d" % (dev, last_partition['part_num'])
273 fs_type = self.g.vfs_type(part_dev)
274 if not re.match("ext[234]", fs_type):
275 warn("Don't know how to resize %s partitions." % vfs_type)
278 self.g.e2fsck_f(part_dev)
279 self.g.resize2fs_M(part_dev)
281 out = self.g.tune2fs_l(part_dev)
283 filter(lambda x: x[0] == 'Block size', out)[0][1])
285 filter(lambda x: x[0] == 'Block count', out)[0][1])
287 sector_size = self.g.blockdev_getss(dev)
289 start = last_partition['part_start'] / sector_size
290 end = start + (block_size * block_cnt) / sector_size - 1
292 self.g.part_del(dev, last_partition['part_num'])
293 self.g.part_add(dev, 'p', start, end)
295 new_size = (end + 1) * sector_size
296 success("new image size is %dMB" %
297 ((new_size + 2 ** 20 - 1) // 2 ** 20))
301 """Returns the "payload" size of the device.
303 The size returned by this method is the size of the space occupied by
304 the partitions (including the space before the first partition).
306 dev = self.g.part_to_dev(self.root)
307 last = self.g.part_list(dev)[-1]
309 return last['part_end'] + 1
311 def dump(self, outfile):
312 """Dumps the content of device into a file.
314 This method will only dump the actual payload, found by reading the
315 partition table. Empty space in the end of the device will be ignored.
317 blocksize = 2 ** 22 # 4MB
319 progress_size = (size + 2 ** 20 - 1) // 2 ** 20 # in MB
320 progressbar = progress("Dumping image file: ", progress_size)
322 source = open(self.device, "r")
324 dest = open(outfile, "w")
330 length = min(left, blocksize)
331 sent = sendfile(dest.fileno(), source.fileno(), offset,
335 for i in range((length + 2 ** 20 - 1) // 2 ** 20):
342 success('Image file %s was successfully created' % outfile)
344 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :