X-Git-Url: https://code.grnet.gr/git/snf-image-creator/blobdiff_plain/e8b1b48bd7b8a7057b6af698b6dfdb36f13c75b8..29fd973e0da4b1bf61f76a7809b67b18ef9db195:/image_creator/disk.py diff --git a/image_creator/disk.py b/image_creator/disk.py index 6632b3e..b4311f8 100644 --- a/image_creator/disk.py +++ b/image_creator/disk.py @@ -32,21 +32,17 @@ # or implied, of GRNET S.A. from image_creator.util import get_command -from image_creator.util import warn, progress, success, output, FatalError -from image_creator.gpt import GPTPartitionTable +from image_creator.util import try_fail_repeat +from image_creator.util import free_space +from image_creator.util import FatalError +from image_creator.bundle_volume import BundleVolume +from image_creator.image import Image + import stat import os import tempfile import uuid -import re -import sys -import guestfs -import time -from sendfile import sendfile - - -class DiskError(Exception): - pass +import shutil dd = get_command('dd') dmsetup = get_command('dmsetup') @@ -54,6 +50,9 @@ losetup = get_command('losetup') blockdev = get_command('blockdev') +TMP_CANDIDATES = ['/var/tmp', os.path.expanduser('~'), '/mnt'] + + class Disk(object): """This class represents a hard disk hosting an Operating System @@ -62,366 +61,137 @@ class Disk(object): the Linux kernel. """ - def __init__(self, source): + def __init__(self, source, output, tmp=None): """Create a new Disk instance out of a source media. The source - media can be an image file, a block device or a directory.""" + media can be an image file, a block device or a directory. + """ self._cleanup_jobs = [] - self._devices = [] + self._images = [] self.source = source + self.out = output + self.meta = {} + self.tmp = tempfile.mkdtemp(prefix='.snf_image_creator.', + dir=self._get_tmp_dir(tmp)) + + self._add_cleanup(shutil.rmtree, self.tmp) + + def _get_tmp_dir(self, default=None): + """Check tmp directory candidates and return the one with the most + available space. + """ + if default is not None: + return default + + space = map(free_space, TMP_CANDIDATES) + + max_idx = 0 + max_val = space[0] + for i, val in zip(range(len(space)), space): + if val > max_val: + max_val = val + max_idx = i + + # Return the candidate path with more available space + return TMP_CANDIDATES[max_idx] def _add_cleanup(self, job, *args): + """Add a new job in the cleanup list""" self._cleanup_jobs.append((job, args)) def _losetup(self, fname): + """Setup a loop device and add it to the cleanup list. The loop device + will be detached when cleanup is called. + """ loop = losetup('-f', '--show', fname) loop = loop.strip() # remove the new-line char - self._add_cleanup(losetup, '-d', loop) + self._add_cleanup(try_fail_repeat, losetup, '-d', loop) return loop def _dir_to_disk(self): - raise NotImplementedError + """Create a disk out of a directory""" + if self.source == '/': + bundle = BundleVolume(self.out, self.meta) + image = '%s/%s.diskdump' % (self.tmp, uuid.uuid4().hex) + + def check_unlink(path): + if os.path.exists(path): + os.unlink(path) + + self._add_cleanup(check_unlink, image) + bundle.create_image(image) + return self._losetup(image) + raise FatalError("Using a directory as media source is supported") 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) + try: + while len(self._images): + image = self._images.pop() + image.destroy() + finally: + # Make sure those are executed even if one of the device.destroy + # methods throws exeptions. + while len(self._cleanup_jobs): + job, args = self._cleanup_jobs.pop() + job(*args) def snapshot(self): """Creates a snapshot of the original source media of the Disk instance. """ - output("Examining source media `%s'..." % self.source, False) + self.out.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()) + self.out.success('looks like a directory') + return self._dir_to_disk() elif stat.S_ISREG(mode): - success('looks like an image file') + self.out.success('looks like an image file') sourcedev = self._losetup(self.source) elif not stat.S_ISBLK(mode): - raise ValueError("Invalid media source. Only block devices, " - "regular files and directories are supported.") + raise FatalError("Invalid media source. Only block devices, " + "regular files and directories are supported.") else: - success('looks like a block device') + self.out.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() + self.out.output("Snapshotting media source...", False) + size = blockdev('--getsz', sourcedev) + cowfd, cow = tempfile.mkstemp(dir=self.tmp) 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)) + # Create cow sparse file + dd('if=/dev/null', 'of=%s' % cow, 'bs=512', 'seek=%d' % int(size)) cowdev = self._losetup(cow) snapshot = uuid.uuid4().hex tablefd, table = tempfile.mkstemp() try: - os.write(tablefd, "0 %d snapshot %s %s n 8" % \ - (int(size), sourcedev, cowdev)) + os.write(tablefd, "0 %d snapshot %s %s n 8" % + (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) + self._add_cleanup(try_fail_repeat, dmsetup, 'remove', snapshot) finally: os.unlink(table) - success('done') + self.out.success('done') return "/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): - """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(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 FatalError("No operating system found") - if len(roots) > 1: - 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): - """Destroy this DiskDevice instance.""" - - if self.guestfs_enabled: - self.g.umount_all() - self.g.sync() - - # Close the guestfs handler if open - self.g.close() - - def progress_callback(self, ev, eh, buf, array): - position = array[2] - total = array[3] + def get_image(self, media): + """Returns a newly created Image instance.""" - self.progressbar.goto((position * 100) // total) + image = Image(media, self.out) + self._images.append(image) + image.enable() + return image - 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. - # / 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 - mps.sort(compare) - for mp, dev in mps: - try: - self.g.mount(dev, mp) - except RuntimeError as 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. + def destroy_image(self, image): + """Destroys an Image instance previously created by get_image method. """ - 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) + self._images.remove(image) + image.destroy() # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :