-#!/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.
+
+from image_creator.util import get_command
+from image_creator.util import warn, progress, success, output
+from image_creator import FatalError
-import losetup
import stat
import os
import tempfile
import re
import sys
import guestfs
-
-from pbs import dmsetup
-from pbs import blockdev
-from pbs import dd
+import time
+from sendfile import sendfile
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()
job(*args)
def get_device(self):
+ """Returns a newly created DiskDevice instance.
+
+ This instance is 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 sparse file
- dd('if=/dev/null', 'of=%s' % cow, 'bs=1k', 'seek=%d' % (1024 * 1024))
+ 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')
new_device = DiskDevice("/dev/mapper/%s" % snapshot)
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):
+ """Create a new DiskDevice."""
+
self.device = device
self.bootable = bootable
+ self.progress_bar = None
self.g = guestfs.GuestFS()
+ self.g.add_drive_opts(self.device, readonly=0)
- self.g.set_trace(1)
+ #self.g.set_trace(1)
+ #self.g.set_verbose(1)
- self.g.add_drive_opts(device, readonly=0)
+ self.guestfs_enabled = False
+
+ def enable(self):
+ """Enable a newly created DiskDevice"""
+ self.progressbar = progress("Launching helper VM: ")
+ self.progressbar.next()
+ 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:
+ self.progressbar.send(100)
+ 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.ostype = self.g.inspect_get_type(self.root)
self.distro = self.g.inspect_get_distro(self.root)
+ success('found a %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.send((position * 100) // total)
+
+ if position == total:
+ self.progressbar = None
def mount(self):
+ """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.
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 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.
+ """
+ output("Shrinking image (this may take a while)...", False)
+
dev = self.g.part_to_dev(self.root)
parttype = self.g.part_get_parttype(dev)
if parttype != 'msdos':
- raise DiskError("You have a %s partition table. "
+ raise FatalError("You have a %s partition table. "
"Only msdos partitions are supported" % parttype)
last_partition = self.g.part_list(dev)[-1]
if last_partition['part_num'] > 4:
- raise DiskError("This disk contains logical partitions. "
+ raise FatalError("This disk contains logical partitions. "
"Only primary partitions are supported.")
part_dev = "%s%d" % (dev, last_partition['part_num'])
fs_type = self.g.vfs_type(part_dev)
if not re.match("ext[234]", fs_type):
- print "Warning, don't know how to resize %s partitions" % vfs_type
+ warn("Don't know how to resize %s partitions." % vfs_type)
return
self.g.e2fsck_f(part_dev)
self.g.resize2fs_M(part_dev)
+
output = self.g.tune2fs_l(part_dev)
- block_size = int(filter(lambda x: x[0] == 'Block size', output)[0][1])
- block_cnt = int(filter(lambda x: x[0] == 'Block count', output)[0][1])
+ block_size = int(
+ filter(lambda x: x[0] == 'Block size', output)[0][1])
+ block_cnt = int(
+ filter(lambda x: x[0] == 'Block count', output)[0][1])
sector_size = self.g.blockdev_getss(dev)
start = last_partition['part_start'] / sector_size
end = start + (block_size * block_cnt) / sector_size - 1
+ self.g.part_del(dev, last_partition['part_num'])
+ self.g.part_add(dev, 'p', start, end)
+
+ new_size = (end + 1) * sector_size
+ success("new image size is %dMB" %
+ ((new_size + 2 ** 20 - 1) // 2 ** 20))
+ return new_size
+
+ def size(self):
+ """Returns the "payload" size of the device.
+
+ The size returned by this method is the size of the space occupied by
+ the partitions (including the space before the first partition).
+ """
+ dev = self.g.part_to_dev(self.root)
+ last = self.g.part_list(dev)[-1]
+
+ return last['part_end'] + 1
+
+ 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.
+ """
+ blocksize = 2 ** 22 # 4MB
+ size = self.size()
+ progress_size = (size + 2 ** 20 - 1) // 2 ** 20 # in MB
+ progressbar = progress("Dumping image file: ", progress_size)
+
+ source = open(self.device, "r")
+ try:
+ dest = open(outfile, "w")
+ try:
+ left = size
+ offset = 0
+ progressbar.next()
+ while left > 0:
+ length = min(left, blocksize)
+ sent = sendfile(dest.fileno(), source.fileno(), offset,
+ length)
+ offset += sent
+ left -= sent
+ for i in range((length + 2 ** 20 - 1) // 2 ** 20):
+ progressbar.next()
+ finally:
+ dest.close()
+ finally:
+ source.close()
+ success('Image file %s was successfully created' % outfile)
# vim: set sta sts=4 shiftwidth=4 sw=4 et ai :
projects / snf-image-creator / blobdiff