-#!/usr/bin/env python
+# Copyright 2012 GRNET S.A. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or
+# without modification, are permitted provided that the following
+# conditions are met:
+#
+# 1. Redistributions of source code must retain the above
+# copyright notice, this list of conditions and the following
+# disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following
+# disclaimer in the documentation and/or other materials
+# provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
+# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+# The views and conclusions contained in the software and
+# documentation are those of the authors and should not be
+# interpreted as representing official policies, either expressed
+# or implied, of GRNET S.A.
-import losetup
+from image_creator.util import get_command
+from image_creator.util import warn, progress, success, output, FatalError
+from image_creator.gpt import GPTPartitionTable
import stat
import os
import tempfile
import re
import sys
import guestfs
+import time
+from sendfile import sendfile
-from pbs import dmsetup
-from pbs import blockdev
-from pbs import dd
-class DiskError(Exception): pass
+class DiskError(Exception):
+ pass
+
+dd = get_command('dd')
+dmsetup = get_command('dmsetup')
+losetup = get_command('losetup')
+blockdev = get_command('blockdev')
+
class Disk(object):
+ """This class represents a hard disk hosting an Operating System
+
+ A Disk instance never alters the source media it is created from.
+ Any change is done on a snapshot created by the device-mapper of
+ the Linux kernel.
+ """
def __init__(self, source):
+ """Create a new Disk instance out of a source media. The source
+ media can be an image file, a block device or a directory."""
self._cleanup_jobs = []
self._devices = []
self.source = source
self._cleanup_jobs.append((job, args))
def _losetup(self, fname):
- loop = losetup.find_unused_loop_device()
- loop.mount(fname)
- self._add_cleanup(loop.unmount)
- return loop.device
+ loop = losetup('-f', '--show', fname)
+ loop = loop.strip() # remove the new-line char
+ self._add_cleanup(losetup, '-d', loop)
+ return loop
def _dir_to_disk(self):
raise NotImplementedError
def cleanup(self):
+ """Cleanup internal data. This needs to be called before the
+ program ends.
+ """
while len(self._devices):
device = self._devices.pop()
device.destroy()
-
+
while len(self._cleanup_jobs):
job, args = self._cleanup_jobs.pop()
job(*args)
- def get_device(self):
+ def snapshot(self):
+ """Creates a snapshot of the original source media of the Disk
+ instance.
+ """
+
+ output("Examining source media `%s'..." % self.source, False)
sourcedev = self.source
mode = os.stat(self.source).st_mode
if stat.S_ISDIR(mode):
+ success('looks like a directory')
return self._losetup(self._dir_to_disk())
elif stat.S_ISREG(mode):
+ success('looks like an image file')
sourcedev = self._losetup(self.source)
elif not stat.S_ISBLK(mode):
- raise ValueError("Value for self.source is invalid")
+ raise ValueError("Invalid media source. Only block devices, "
+ "regular files and directories are supported.")
+ else:
+ success('looks like a block device')
# Take a snapshot and return it to the user
+ output("Snapshotting media source...", False)
size = blockdev('--getsize', sourcedev)
cowfd, cow = tempfile.mkstemp()
+ os.close(cowfd)
self._add_cleanup(os.unlink, cow)
- # Create 1G cow file
- dd('if=/dev/null', 'of=%s' % cow, 'bs=1k' ,'seek=%d' % (1024*1024))
+ # Create 1G cow sparse file
+ dd('if=/dev/null', 'of=%s' % cow, 'bs=1k', 'seek=%d' % (1024 * 1024))
cowdev = self._losetup(cow)
snapshot = uuid.uuid4().hex
(int(size), sourcedev, cowdev))
dmsetup('create', snapshot, table)
self._add_cleanup(dmsetup, 'remove', snapshot)
+ # Sometimes dmsetup remove fails with Device or resource busy,
+ # although everything is cleaned up and the snapshot is not
+ # used by anyone. Add a 2 seconds delay to be on the safe side.
+ self._add_cleanup(time.sleep, 2)
+
finally:
os.unlink(table)
+ success('done')
+ return "/dev/mapper/%s" % snapshot
- new_device = DiskDevice("/dev/mapper/%s" % snapshot)
+ def get_device(self, media):
+ """Returns a newly created DiskDevice instance."""
+
+ new_device = DiskDevice(media)
self._devices.append(new_device)
+ new_device.enable()
return new_device
def destroy_device(self, device):
+ """Destroys a DiskDevice instance previously created by
+ get_device method.
+ """
self._devices.remove(device)
device.destroy()
+
class DiskDevice(object):
+ """This class represents a block device hosting an Operating System
+ as created by the device-mapper.
+ """
- def __init__(self, device, bootable = True):
- self.device = device
+ def __init__(self, device, bootable=True):
+ """Create a new DiskDevice."""
+
+ self.real_device = device
self.bootable = bootable
+ self.progress_bar = None
+ self.guestfs_device = None
+ self.meta = {}
self.g = guestfs.GuestFS()
- self.g.add_drive_opts(device, readonly = 0)
+ self.g.add_drive_opts(self.real_device, readonly=0)
+
+ #self.g.set_trace(1)
+ #self.g.set_verbose(1)
+
+ self.guestfs_enabled = False
+
+ def enable(self):
+ """Enable a newly created DiskDevice"""
+ self.progressbar = progress("Launching helper VM: ", "percent")
+ self.progressbar.max = 100
+ self.progressbar.goto(1)
+ eh = self.g.set_event_callback(self.progress_callback,
+ guestfs.EVENT_PROGRESS)
self.g.launch()
+ self.guestfs_enabled = True
+ self.g.delete_event_callback(eh)
+ if self.progressbar is not None:
+ output("\rLaunching helper VM...\033[K", False)
+ success("done")
+ self.progressbar = None
+
+ output('Inspecting Operating System...', False)
roots = self.g.inspect_os()
if len(roots) == 0:
- raise DiskError("No operating system found")
+ raise FatalError("No operating system found")
if len(roots) > 1:
- raise DiskError("Multiple operating systems found")
-
+ raise FatalError("Multiple operating systems found."
+ "We only support images with one filesystem.")
self.root = roots[0]
+ self.guestfs_device = self.g.part_to_dev(self.root)
+ self.meta['SIZE'] = self.g.blockdev_getsize64(self.guestfs_device)
+ self.meta['PARTITION_TABLE'] = \
+ self.g.part_get_parttype(self.guestfs_device)
+
self.ostype = self.g.inspect_get_type(self.root)
self.distro = self.g.inspect_get_distro(self.root)
-
+ success('found a(n) %s system' % self.distro)
+
def destroy(self):
- self.g.umount_all()
- self.g.sync()
- # Close the guestfs handler
+ """Destroy this DiskDevice instance."""
+
+ if self.guestfs_enabled:
+ self.g.umount_all()
+ self.g.sync()
+
+ # Close the guestfs handler if open
self.g.close()
- del self.g
-
+
+ def progress_callback(self, ev, eh, buf, array):
+ position = array[2]
+ total = array[3]
+
+ self.progressbar.goto((position * 100) // total)
+
def mount(self):
- mps = g.inspect_get_mountpoints(self.root)
+ """Mount all disk partitions in a correct order."""
+
+ output("Mounting image...", False)
+ mps = self.g.inspect_get_mountpoints(self.root)
+
# Sort the keys to mount the fs in a correct order.
# / should be mounted befor /boot, etc
- def compare (a, b):
- if len(a[0]) > len(b[0]): return 1
- elif len(a[0]) == len(b[0]): return 0
- else: return -1
+ def compare(a, b):
+ if len(a[0]) > len(b[0]):
+ return 1
+ elif len(a[0]) == len(b[0]):
+ return 0
+ else:
+ return -1
mps.sort(compare)
for mp, dev in mps:
try:
self.g.mount(dev, mp)
except RuntimeError as msg:
- print "%s (ignored)" % msg
+ warn("%s (ignored)" % msg)
+ success("done")
+
+ def umount(self):
+ """Umount all mounted filesystems."""
+ self.g.umount_all()
+
+ def _last_partition(self):
+ if self.meta['PARTITION_TABLE'] not in 'msdos' 'gpt':
+ msg = "Unsupported partition table: %s. Only msdos and gpt " \
+ "partition tables are supported" % self.meta['PARTITION_TABLE']
+ raise FatalError(msg)
+
+ is_extended = lambda p: self.g.part_get_mbr_id(
+ self.guestfs_device, p['part_num']) == 5
+ is_logical = lambda p: self.meta['PARTITION_TABLE'] != 'msdos' and \
+ p['part_num'] > 4
+
+ partitions = self.g.part_list(self.guestfs_device)
+ last_partition = partitions[-1]
+
+ if is_logical(last_partition):
+ # The disk contains extended and logical partitions....
+ extended = [p for p in partitions if is_extended(p)][0]
+ last_primary = [p for p in partitions if p['part_num'] <= 4][-1]
+
+ # check if extended is the last primary partition
+ if last_primary['part_num'] > extended['part_num']:
+ last_partition = last_primary
+
+ return last_partition
+
+ def shrink(self):
+ """Shrink the disk.
+
+ This is accomplished by shrinking the last filesystem in the
+ disk and then updating the partition table. The new disk size
+ (in bytes) is returned.
+
+ ATTENTION: make sure unmount is called before shrink
+ """
+ get_fstype = lambda p: self.g.vfs_type("%s%d" % \
+ (self.guestfs_device, p['part_num']))
+ is_logical = lambda p: self.meta['PARTITION_TABLE'] == 'msdos' and \
+ p['part_num'] > 4
+ is_extended = lambda p: self.meta['PARTITION_TABLE'] == 'msdos' and \
+ self.g.part_get_mbr_id(self.guestfs_device, p['part_num']) == 5
+
+ part_add = lambda ptype, start, stop: \
+ self.g.part_add(self.guestfs_device, ptype, start, stop)
+ part_del = lambda p: self.g.part_del(self.guestfs_device, p)
+ part_get_id = lambda p: self.g.part_get_mbr_id(self.guestfs_device, p)
+ part_set_id = lambda p, id: self.g.part_set_mbr_id(
+ self.guestfs_device, p, id)
+ part_get_bootable = lambda p: self.g.part_get_bootable(
+ self.guestfs_device, p)
+ part_set_bootable = lambda p, bootable: self.g.part_set_bootable(
+ self.guestfs_device, p, bootable)
+
+ MB = 2 ** 20
+
+ output("Shrinking image (this may take a while)...", False)
+
+ last_part = None
+ fstype = None
+ while True:
+ last_part = self._last_partition()
+ fstype = get_fstype(last_part)
+
+ if fstype == 'swap':
+ self.meta['SWAP'] = "%d:%s" % \
+ (last_part['part_num'],
+ (last_part['part_size'] + MB - 1) // MB)
+ part_del(last_part['part_num'])
+ continue
+ elif is_extended(last_part):
+ part_del(last_part['part_num'])
+ continue
+
+ self.meta['SIZE'] = last_part['part_end'] + 1
+ break
+
+ if not re.match("ext[234]", fstype):
+ warn("Don't know how to resize %s partitions." % fstype)
+ return self.meta['SIZE']
+
+ part_dev = "%s%d" % (self.guestfs_device, last_part['part_num'])
+ self.g.e2fsck_f(part_dev)
+ self.g.resize2fs_M(part_dev)
+
+ out = self.g.tune2fs_l(part_dev)
+ block_size = int(
+ filter(lambda x: x[0] == 'Block size', out)[0][1])
+ block_cnt = int(
+ filter(lambda x: x[0] == 'Block count', out)[0][1])
+
+ sector_size = self.g.blockdev_getss(self.guestfs_device)
+ start = last_part['part_start'] / sector_size
+ end = start + (block_size * block_cnt) / sector_size - 1
+
+ if is_logical(last_part):
+ partitions = self.g.part_list(self.guestfs_device)
+
+ logical = [] # logical partitions
+ for partition in partitions:
+ if partition['part_num'] < 4:
+ continue
+ logical.append({
+ 'num': partition['part_num'],
+ 'start': partition['part_start'] / sector_size,
+ 'end': partition['part_end'] / sector_size,
+ 'id': part_get_(partition['part_num']),
+ 'bootable': part_get_bootable(partition['part_num'])
+ })
+
+ logical[-1]['end'] = end # new end after resize
+
+ # Recreate the extended partition
+ extended = [p for p in partitions if self._is_extended(p)][0]
+ part_del(extended['part_num'])
+ part_add('e', extended['part_start'], end)
+
+ # Create all the logical partitions back
+ for l in logical:
+ part_add('l', l['start'], l['end'])
+ part_set_id(l['num'], l['id'])
+ part_set_bootable(l['num'], l['bootable'])
+ else:
+ # Recreate the last partition
+ if self.meta['PARTITION_TABLE'] == 'msdos':
+ last_part['id'] = part_get_id(last_part['part_num'])
+
+ last_part['bootable'] = part_get_bootable(last_part['part_num'])
+ part_del(last_part['part_num'])
+ part_add('p', start, end)
+ part_set_bootable(last_part['part_num'], last_part['bootable'])
+
+ if self.meta['PARTITION_TABLE'] == 'msdos':
+ part_set_id(last_part['part_num'], last_part['id'])
+
+ new_size = (end + 1) * sector_size
+ success("new size is %dMB" % ((new_size + MB - 1) // MB))
+
+ if self.meta['PARTITION_TABLE'] == 'gpt':
+ ptable = GPTPartitionTable(self.real_device)
+ self.meta['SIZE'] = ptable.shrink(new_size)
+ else:
+ self.meta['SIZE'] = new_size
+
+ return self.meta['SIZE']
+
+ def dump(self, outfile):
+ """Dumps the content of device into a file.
+
+ This method will only dump the actual payload, found by reading the
+ partition table. Empty space in the end of the device will be ignored.
+ """
+ MB = 2 ** 20
+ blocksize = 4 * MB # 4MB
+ size = self.meta['SIZE']
+ progress_size = (size + MB - 1) // MB # in MB
+ progressbar = progress("Dumping image file: ", 'mb')
+ progressbar.max = progress_size
+
+ with open(self.real_device, 'r') as src:
+ with open(outfile, "w") as dst:
+ left = size
+ offset = 0
+ progressbar.next()
+ while left > 0:
+ length = min(left, blocksize)
+ sent = sendfile(dst.fileno(), src.fileno(), offset, length)
+ offset += sent
+ left -= sent
+ progressbar.goto((size - left) // MB)
+ output("\rDumping image file...\033[K", False)
+ success('image file %s was successfully created' % outfile)
# vim: set sta sts=4 shiftwidth=4 sw=4 et ai :
projects / snf-image-creator / blobdiff