Synnefo » snf-image-creator

# -*- coding: utf-8 -*-

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from image_creator.util import FatalError

from image_creator.gpt import GPTPartitionTable

from image_creator.os_type import os_cls

import re

import guestfs

from sendfile import sendfile

class Image(object):

    """The instances of this class can create images out of block devices."""

    def __init__(self, device, output, **kargs):

        """Create a new Image instance"""

        self.device = device

        self.out = output

        self.meta = kargs['meta'] if 'meta' in kargs else {}

        self.sysprep_params = \

            kargs['sysprep_params'] if 'sysprep_params' in kargs else {}

        self.progress_bar = None

        self.guestfs_device = None

        self.size = 0

        self.g = guestfs.GuestFS()

        self.guestfs_enabled = False

        self.guestfs_version = self.g.version()

    def check_guestfs_version(self, major, minor, release):

        """Checks if the version of the used libguestfs is smaller, equal or

        greater than the one specified by the major, minor and release triplet

        Returns:

            < 0 if the installed version is smaller than the specified one

            = 0 if they are equal

            > 0 if the installed one is greater than the specified one

        """

        for (a, b) in (self.guestfs_version['major'], major), \

                (self.guestfs_version['minor'], minor), \

                (self.guestfs_version['release'], release):

            if a != b:

                return a - b

        return 0

    def enable(self):

        """Enable a newly created Image instance"""

        self.enable_guestfs()

        self.out.output('Inspecting Operating System ...', False)

        roots = self.g.inspect_os()

        if len(roots) == 0 or len(roots) > 1:

            self.root = None

            self.ostype = "unsupported"

            self.distro = "unsupported"

            self.guestfs_device = '/dev/sda'

            self.size = self.g.blockdev_getsize64(self.guestfs_device)

            if len(roots) > 1:

                reason = "Multiple operating systems found on the media."

            else:

                reason = "Unable to detect any operating system on the media."

            self.set_unsupported(reason)

            return

        self.root = roots[0]

        self.meta['PARTITION_TABLE'] = self.g.part_get_parttype('/dev/sda')

        self.guestfs_device = '/dev/sda'  # self.g.part_to_dev(self.root)

        self.size = self.g.blockdev_getsize64(self.guestfs_device)

        self.ostype = self.g.inspect_get_type(self.root)

        self.distro = self.g.inspect_get_distro(self.root)

        self.out.success(

            'found a(n) %s system' %

            self.ostype if self.distro == "unknown" else self.distro)

        # Inspect the OS

        self.os.inspect()

    def set_unsupported(self, reason):

        """Flag this image us ansupported"""

        self._unsupported = reason

        self.meta['UNSUPPORTED'] = reason

        self.out.warn('Media is not supported. Reason: %s' % reason)

    def is_unsupported(self):

        """Returns if this image is unsupported"""

        return hasattr(self, '_unsupported')

    def enable_guestfs(self):

        """Enable the guestfs handler"""

        if self.guestfs_enabled:

            self.out.warn("Guestfs is already enabled")

            return

        # Before version 1.18.4 the behaviour of kill_subprocess was different

        # and you need to reset the guestfs handler to relaunch a previously

        # shut down qemu backend

        if self.check_guestfs_version(1, 18, 4) < 0:

            self.g = guestfs.GuestFS()

        self.g.add_drive_opts(self.device, readonly=0, format="raw")

        # Before version 1.17.14 the recovery process, which is a fork of the

        # original process that called libguestfs, did not close its inherited

        # file descriptors. This can cause problems especially if the parent

        # process has opened pipes. Since the recovery process is an optional

        # feature of libguestfs, it's better to disable it.

        if self.check_guestfs_version(1, 17, 14) >= 0:

            self.out.output("Enabling recovery proc")

            self.g.set_recovery_proc(1)

        else:

            self.g.set_recovery_proc(0)

        #self.g.set_trace(1)

        #self.g.set_verbose(1)

        self.out.output('Launching helper VM (may take a while) ...', False)

        # self.progressbar = self.out.Progress(100, "Launching helper VM",

        #                                     "percent")

        # 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)

        # self.progressbar.success('done')

        # self.progressbar = None

        if self.check_guestfs_version(1, 18, 4) < 0:

            self.g.inspect_os()  # some calls need this

        self.out.success('done')

    def disable_guestfs(self):

        """Disable the guestfs handler"""

        if not self.guestfs_enabled:

            self.out.warn("Guestfs is already disabled")

            return

        self.out.output("Shutting down helper VM ...", False)

        self.g.sync()

        # guestfs_shutdown which is the prefered way to shutdown the backend

        # process was introduced in version 1.19.16

        if self.check_guestfs_version(1, 19, 16) >= 0:

            self.g.shutdown()

        else:

            self.g.kill_subprocess()

        self.guestfs_enabled = False

        self.out.success('done')

    def _get_os(self):

        """Return an OS class instance for this image"""

        if hasattr(self, "_os"):

            return self._os

        if not self.guestfs_enabled:

            self.enable()

        cls = os_cls(self.distro, self.ostype)

        self._os = cls(self, sysprep_params=self.sysprep_params)

        self._os.collect_metadata()

        return self._os

    os = property(_get_os)

    def destroy(self):

        """Destroy this Image instance."""

        # In new guestfs versions, there is a handy shutdown method for this

        try:

            if self.guestfs_enabled:

                self.g.umount_all()

                self.g.sync()

        finally:

            # Close the guestfs handler if open

            self.g.close()

#    def progress_callback(self, ev, eh, buf, array):

#        position = array[2]

#        total = array[3]

#

#        self.progressbar.goto((position * 100) // total)

    def _last_partition(self):

        """Return the last partition of the image disk"""

        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']) \

            in (0x5, 0xf)

        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 = filter(is_extended, partitions)[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 image.

        This is accomplished by shrinking the last file system of the

        image 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']) \

            in (0x5, 0xf)

        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

        self.out.output("Shrinking image (this may take a while) ...", False)

        if self.is_unsupported():

            self.out.warn("Shrinking is disabled for unsupported images")

            return self.size

        sector_size = self.g.blockdev_getss(self.guestfs_device)

        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

            # Most disk manipulation programs leave 2048 sectors after the last

            # partition

            new_size = last_part['part_end'] + 1 + 2048 * sector_size

            self.size = min(self.size, new_size)

            break

        if not re.match("ext[234]", fstype):

            self.out.warn("Don't know how to shrink %s partitions." % fstype)

            return self.size

        part_dev = "%s%d" % (self.guestfs_device, last_part['part_num'])

        if self.check_guestfs_version(1, 15, 17) >= 0:

            self.g.e2fsck(part_dev, forceall=1)

        else:

            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])

        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_id(partition['part_num']),

                    'bootable': part_get_bootable(partition['part_num'])

                })

            logical[-1]['end'] = end  # new end after resize

            # Recreate the extended partition

            extended = filter(is_extended, partitions)[0]

            part_del(extended['part_num'])

            part_add('e', extended['part_start'] / sector_size, 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

        assert (new_size <= self.size)

        if self.meta['PARTITION_TABLE'] == 'gpt':

            ptable = GPTPartitionTable(self.device)

            self.size = ptable.shrink(new_size, self.size)

        else:

            self.size = min(new_size + 2048 * sector_size, self.size)

        self.out.success("new size is %dMB" % ((self.size + MB - 1) // MB))

        return self.size

    def dump(self, outfile):

        """Dumps the content of the image 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.size

        progr_size = (size + MB - 1) // MB  # in MB

        progressbar = self.out.Progress(progr_size, "Dumping image file", 'mb')

        with open(self.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)

                    # Workaround for python-sendfile API change. In

                    # python-sendfile 1.2.x (py-sendfile) the returning value

                    # of sendfile is a tuple, where in version 2.x (pysendfile)

                    # it is just a sigle integer.

                    if isinstance(sent, tuple):

                        sent = sent[1]

                    offset += sent

                    left -= sent

                    progressbar.goto((size - left) // MB)

        progressbar.success('image file %s was successfully created' % outfile)

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