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
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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: ", "percent")
183 self.progressbar.max = 100
184 self.progressbar.goto(1)
185 eh = self.g.set_event_callback(self.progress_callback,
186 guestfs.EVENT_PROGRESS)
188 self.guestfs_enabled = True
189 self.g.delete_event_callback(eh)
190 if self.progressbar is not None:
191 output("\rLaunching helper VM...\033[K", False)
193 self.progressbar = None
195 output('Inspecting Operating System...', False)
196 roots = self.g.inspect_os()
198 raise FatalError("No operating system found")
200 raise FatalError("Multiple operating systems found."
201 "We only support images with one filesystem.")
203 self.ostype = self.g.inspect_get_type(self.root)
204 self.distro = self.g.inspect_get_distro(self.root)
205 success('found a %s system' % self.distro)
208 """Destroy this DiskDevice instance."""
210 if self.guestfs_enabled:
214 # Close the guestfs handler if open
217 def progress_callback(self, ev, eh, buf, array):
221 self.progressbar.goto((position * 100) // total)
224 """Mount all disk partitions in a correct order."""
226 output("Mounting image...", False)
227 mps = self.g.inspect_get_mountpoints(self.root)
229 # Sort the keys to mount the fs in a correct order.
230 # / should be mounted befor /boot, etc
232 if len(a[0]) > len(b[0]):
234 elif len(a[0]) == len(b[0]):
241 self.g.mount(dev, mp)
242 except RuntimeError as msg:
243 warn("%s (ignored)" % msg)
247 """Umount all mounted filesystems."""
253 This is accomplished by shrinking the last filesystem in the
254 disk and then updating the partition table. The new disk size
255 (in bytes) is returned.
257 output("Shrinking image (this may take a while)...", False)
259 dev = self.g.part_to_dev(self.root)
260 parttype = self.g.part_get_parttype(dev)
261 if parttype != 'msdos':
262 raise FatalError("You have a %s partition table. "
263 "Only msdos partitions are supported" % parttype)
265 last_partition = self.g.part_list(dev)[-1]
267 if last_partition['part_num'] > 4:
268 raise FatalError("This disk contains logical partitions. "
269 "Only primary partitions are supported.")
271 part_dev = "%s%d" % (dev, last_partition['part_num'])
272 fs_type = self.g.vfs_type(part_dev)
273 if not re.match("ext[234]", fs_type):
274 warn("Don't know how to resize %s partitions." % vfs_type)
277 self.g.e2fsck_f(part_dev)
278 self.g.resize2fs_M(part_dev)
280 out = self.g.tune2fs_l(part_dev)
282 filter(lambda x: x[0] == 'Block size', out)[0][1])
284 filter(lambda x: x[0] == 'Block count', out)[0][1])
286 sector_size = self.g.blockdev_getss(dev)
288 start = last_partition['part_start'] / sector_size
289 end = start + (block_size * block_cnt) / sector_size - 1
291 self.g.part_del(dev, last_partition['part_num'])
292 self.g.part_add(dev, 'p', start, end)
294 new_size = (end + 1) * sector_size
295 success("new image size is %dMB" %
296 ((new_size + 2 ** 20 - 1) // 2 ** 20))
300 """Returns the "payload" size of the device.
302 The size returned by this method is the size of the space occupied by
303 the partitions (including the space before the first partition).
305 dev = self.g.part_to_dev(self.root)
306 last = self.g.part_list(dev)[-1]
308 return last['part_end'] + 1
310 def dump(self, outfile):
311 """Dumps the content of device into a file.
313 This method will only dump the actual payload, found by reading the
314 partition table. Empty space in the end of the device will be ignored.
316 blocksize = 2 ** 22 # 4MB
318 progress_size = (size + 2 ** 20 - 1) // 2 ** 20 # in MB
319 progressbar = progress("Dumping image file: ", 'mb')
320 progressbar.max = progress_size
321 source = open(self.device, "r")
323 dest = open(outfile, "w")
329 length = min(left, blocksize)
330 sent = sendfile(dest.fileno(), source.fileno(), offset,
334 progressbar.goto((size - left) // 2 ** 20)
340 output("\rDumping image file...\033[K", False)
341 success('image file %s was successfully created' % outfile)
343 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :