1 # Copyright 2012 GRNET S.A. All rights reserved.
3 # Redistribution and use in source and binary forms, with or
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
13 # disclaimer in the documentation and/or other materials
14 # provided with the distribution.
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17 # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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32 # or implied, of GRNET S.A.
34 from image_creator.util import get_command, warn, progress_generator
35 from image_creator import FatalError
36 from clint.textui import indent, puts, colored
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 """Returns a newly created DiskDevice instance.
99 This instance is a snapshot of the original source media of
103 puts("Examining source media `%s'..." % self.source, False)
104 sourcedev = self.source
105 mode = os.stat(self.source).st_mode
106 if stat.S_ISDIR(mode):
107 puts(colored.green('looks like a directory'))
108 return self._losetup(self._dir_to_disk())
109 elif stat.S_ISREG(mode):
110 puts(colored.green('looks like an image file'))
111 sourcedev = self._losetup(self.source)
112 elif not stat.S_ISBLK(mode):
113 raise ValueError("Invalid media source. Only block devices, "
114 "regular files and directories are supported.")
116 puts(colored.green('looks like a block device'))
118 # Take a snapshot and return it to the user
119 puts("Snapshotting media source...", False)
120 size = blockdev('--getsize', sourcedev)
121 cowfd, cow = tempfile.mkstemp()
123 self._add_cleanup(os.unlink, cow)
124 # Create 1G cow sparse file
125 dd('if=/dev/null', 'of=%s' % cow, 'bs=1k', \
126 'seek=%d' % (1024 * 1024))
127 cowdev = self._losetup(cow)
129 snapshot = uuid.uuid4().hex
130 tablefd, table = tempfile.mkstemp()
132 os.write(tablefd, "0 %d snapshot %s %s n 8" % \
133 (int(size), sourcedev, cowdev))
134 dmsetup('create', snapshot, table)
135 self._add_cleanup(dmsetup, 'remove', snapshot)
136 # Sometimes dmsetup remove fails with Device or resource busy,
137 # although everything is cleaned up and the snapshot is not
138 # used by anyone. Add a 2 seconds delay to be on the safe side.
139 self._add_cleanup(time.sleep, 2)
143 puts(colored.green('done'))
144 new_device = DiskDevice("/dev/mapper/%s" % snapshot)
145 self._devices.append(new_device)
149 def destroy_device(self, device):
150 """Destroys a DiskDevice instance previously created by
153 self._devices.remove(device)
157 class DiskDevice(object):
158 """This class represents a block device hosting an Operating System
159 as created by the device-mapper.
162 def __init__(self, device, bootable=True):
163 """Create a new DiskDevice."""
166 self.bootable = bootable
167 self.progress_bar = None
169 self.g = guestfs.GuestFS()
170 self.g.add_drive_opts(self.device, readonly=0)
173 #self.g.set_verbose(1)
175 self.guestfs_enabled = False
178 """Enable a newly created DiskDevice"""
179 self.progressbar = progress_generator("Launching helper VM: ")
180 self.progressbar.next()
181 eh = self.g.set_event_callback(self.progress_callback,
182 guestfs.EVENT_PROGRESS)
184 self.guestfs_enabled = True
185 self.g.delete_event_callback(eh)
186 if self.progressbar is not None:
187 self.progressbar.send(100)
188 self.progressbar = None
190 puts('Inspecting Operating System...', False)
191 roots = self.g.inspect_os()
193 raise FatalError("No operating system found")
195 raise FatalError("Multiple operating systems found."
196 "We only support images with one filesystem.")
198 self.ostype = self.g.inspect_get_type(self.root)
199 self.distro = self.g.inspect_get_distro(self.root)
200 puts(colored.green('found a %s system' % self.distro))
203 """Destroy this DiskDevice instance."""
205 if self.guestfs_enabled:
209 # Close the guestfs handler if open
212 def progress_callback(self, ev, eh, buf, array):
216 self.progressbar.send((position * 100) // total)
218 if position == total:
219 self.progressbar = None
222 """Mount all disk partitions in a correct order."""
223 mps = self.g.inspect_get_mountpoints(self.root)
225 # Sort the keys to mount the fs in a correct order.
226 # / should be mounted befor /boot, etc
228 if len(a[0]) > len(b[0]):
230 elif len(a[0]) == len(b[0]):
237 self.g.mount(dev, mp)
238 except RuntimeError as msg:
239 print "%s (ignored)" % msg
242 """Umount all mounted filesystems."""
248 This is accomplished by shrinking the last filesystem in the
249 disk and then updating the partition table. The new disk size
250 (in bytes) is returned.
252 puts("Shrinking image (this may take a while)...", False)
254 dev = self.g.part_to_dev(self.root)
255 parttype = self.g.part_get_parttype(dev)
256 if parttype != 'msdos':
257 raise FatalError("You have a %s partition table. "
258 "Only msdos partitions are supported" % parttype)
260 last_partition = self.g.part_list(dev)[-1]
262 if last_partition['part_num'] > 4:
263 raise FatalError("This disk contains logical partitions. "
264 "Only primary partitions are supported.")
266 part_dev = "%s%d" % (dev, last_partition['part_num'])
267 fs_type = self.g.vfs_type(part_dev)
268 if not re.match("ext[234]", fs_type):
269 warn("Don't know how to resize %s partitions." % vfs_type)
272 self.g.e2fsck_f(part_dev)
273 self.g.resize2fs_M(part_dev)
275 output = self.g.tune2fs_l(part_dev)
277 filter(lambda x: x[0] == 'Block size', output)[0][1])
279 filter(lambda x: x[0] == 'Block count', output)[0][1])
281 sector_size = self.g.blockdev_getss(dev)
283 start = last_partition['part_start'] / sector_size
284 end = start + (block_size * block_cnt) / sector_size - 1
286 self.g.part_del(dev, last_partition['part_num'])
287 self.g.part_add(dev, 'p', start, end)
289 new_size = (end + 1) * sector_size
290 puts(colored.green("new image size is %dMB\n" % (new_size // 2 ** 20)))
295 """Returns the "payload" size of the device.
297 The size returned by this method is the size of the space occupied by
298 the partitions (including the space before the first partition).
300 dev = self.g.part_to_dev(self.root)
301 last = self.g.part_list(dev)[-1]
303 return last['part_end']
305 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :