mirror of
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322 lines
11 KiB
Python
322 lines
11 KiB
Python
# Sample code to parse an image XML description and
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# spit out libvirt XML
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#
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# Copyright 2007, 2013 Red Hat, Inc.
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# David Lutterkort <dlutter@redhat.com>
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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# MA 02110-1301 USA.
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import logging
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import os
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import urlgrabber
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from virtinst import CapabilitiesParser
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from virtinst import util
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class Image(object):
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"""The toplevel object representing a VM image"""
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def __init__(self, node=None, base=None, filename=None):
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self.storage = {}
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self.domain = None
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if filename is None:
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self.filename = None
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else:
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self.filename = os.path.abspath(filename)
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if base is None:
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if filename is not None:
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self.base = os.path.dirname(filename)
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if self.base == '':
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self.base = "."
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else:
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self.base = "."
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else:
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self.base = base
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self.name = None
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self.label = None
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self.descr = None
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self.version = None
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self.release = None
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if not node is None:
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self.parseXML(node)
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def abspath(self, p):
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"""Turn P into an absolute path. Relative paths are taken relative
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to self.BASE"""
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return os.path.abspath(os.path.join(self.base, p))
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def parseXML(self, node):
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self.name = xpathString(node, "name")
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self.label = xpathString(node, "label")
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self.descr = xpathString(node, "description")
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self.version = xpathString(node, "name/@version")
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self.release = xpathString(node, "name/@release")
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for d in node.xpathEval("storage/disk"):
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disk = Disk(d)
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if disk.file is None:
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disk.id = "disk%d.img" % len(self.storage)
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disk.file = "disk%d.img" % (len(self.storage) + 1)
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if disk.id in self.storage:
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raise RuntimeError("Disk file '%s' defined twice" % disk.file)
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self.storage[disk.id] = disk
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lm = node.xpathEval("domain")
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if len(lm) == 1:
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self.domain = Domain(lm[0])
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else:
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raise RuntimeError(_("Expected exactly one 'domain' element"))
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# Connect the disk maps to the disk definitions
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for boot in self.domain.boots:
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for d in boot.drives:
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if d.disk_id not in self.storage:
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raise RuntimeError(_("Disk entry for '%s' not found")
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% d.disk_id)
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d.disk = self.storage[d.disk_id]
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class Domain(object):
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"""The description of a virtual domain as part of an image"""
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def __init__(self, node=None):
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self.boots = []
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self.vcpu = None
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self.memory = None
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self.interface = 0
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self.graphics = None
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if not node is None:
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self.parseXML(node)
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def parseXML(self, node):
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self.boots = [Boot(b) for b in node.xpathEval("boot")]
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self.vcpu = xpathString(node, "devices/vcpu", 1)
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tmpmem = xpathString(node, "devices/memory")
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self.interface = int(node.xpathEval("count(devices/interface)"))
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self.graphics = node.xpathEval("count(devices/graphics)") > 0
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if tmpmem is not None:
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try:
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self.memory = int(tmpmem)
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except ValueError:
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raise RuntimeError(_("Memory must be an integer, "
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"but is '%s'") % self.memory)
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else:
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tmpmem = 0
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class ImageFeatures(CapabilitiesParser.Features):
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def __init__(self, node=None):
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CapabilitiesParser.Features.__init__(self, node)
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def _extractFeature(self, feature, d, n):
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state = xpathString(n, "@state", "on")
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if state == "on":
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d[feature] = CapabilitiesParser.FEATURE_ON
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elif state == "off":
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d[feature] = CapabilitiesParser.FEATURE_OFF
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else:
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raise RuntimeError("The state for feature %s must be "
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"either 'on' or 'off', but is '%s'" %
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(feature, state))
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class Boot(object):
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"""The overall description of how the image can be booted, including
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required capabilities of the host and mapping of disks into the VM"""
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def __init__(self, node=None):
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# 'xen' or 'hvm'
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self.type = None
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# Either 'pygrub' or nothing; might have others in the future
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# For HVM, figure outhte right loader based on the guest
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self.loader = None
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# Only used for hvm
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self.bootdev = None
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self.kernel = None
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self.initrd = None
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self.cmdline = None
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self.drives = []
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self.arch = None
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self.features = ImageFeatures()
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if not node is None:
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self.parseXML(node)
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def parseXML(self, node):
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self.type = xpathString(node, "@type")
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self.loader = xpathString(node, "os/loader")
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self.bootdev = xpathString(node, "os/loader/@dev")
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self.kernel = xpathString(node, "os/kernel")
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self.initrd = xpathString(node, "os/initrd")
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self.cmdline = xpathString(node, "os/cmdline")
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self.arch = util.sanitize_arch(xpathString(node, "guest/arch"))
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fl = node.xpathEval("guest/features")
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if len(fl) > 1:
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raise RuntimeError("Expected at most one <features> element "
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"in %s boot descriptor for %s" %
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(self.type, self.arch))
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elif len(fl) == 1:
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self.features = ImageFeatures(fl[0])
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for d in node.xpathEval("drive"):
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self.drives.append(Drive(d))
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validate(self.type is not None,
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"The boot type must be provided")
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validate(self.type == "hvm" or self.type == "xen",
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"Boot type must be 'xen' or 'hvm', but is %s" % self.type)
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validate(self.arch is not None, "Missing guest arch")
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validate(self.loader is None or self.loader == "pygrub",
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"Invalid loader %s" % self.loader)
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validate([None, "hd", "cdrom"].count(self.bootdev) > 0,
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"Invalid bootdev %s" % self.bootdev)
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# We should make sure that kernel/initrd/cmdline are only used for pv
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# and without a loader
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class Drive(object):
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"""The mapping of a disk from the storage section to a virtual drive
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in a guest"""
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def __init__(self, node=None):
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self.disk_id = None
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self.target = None
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self.disk = None # Will point to the underlying Disk object
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if node:
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self.parseXML(node)
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def parseXML(self, node):
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self.disk_id = xpathString(node, "@disk")
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self.target = xpathString(node, "@target")
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class Disk(object):
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FORMAT_RAW = "raw"
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FORMAT_ISO = "iso"
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FORMAT_QCOW = "qcow"
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FORMAT_QCOW2 = "qcow2"
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FORMAT_VMDK = "vmdk"
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FORMAT_VDI = "vdi"
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USE_SYSTEM = "system"
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USE_USER = "user"
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USE_SCRATCH = "scratch"
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def __init__(self, node=None):
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self.id = None
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self.file = None
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self.format = None
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self.size = None
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self.use = None
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self.csum = {}
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if not node is None:
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self.parseXML(node)
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def parseXML(self, node):
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self.file = xpathString(node, "@file")
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self.id = xpathString(node, "@id", self.file)
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self.format = xpathString(node, "@format", Disk.FORMAT_RAW)
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self.size = xpathString(node, "@size")
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self.use = xpathString(node, "@use", Disk.USE_SYSTEM)
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for d in node.xpathEval("checksum"):
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csumtype = xpathString(d, "@type")
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csumvalue = xpathString(d, "")
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self.csum[csumtype] = csumvalue
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formats = [Disk.FORMAT_RAW,
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Disk.FORMAT_QCOW,
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Disk.FORMAT_QCOW2,
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Disk.FORMAT_VMDK,
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Disk.FORMAT_ISO,
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Disk.FORMAT_VDI]
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validate(formats.count(self.format) > 0,
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_("The format for disk %s must be one of %s") %
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(self.file, ",".join(formats)))
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def check_disk_signature(self, meter=None):
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try:
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import hashlib
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sha = None
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except:
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import sha
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hashlib = None
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if meter is None:
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meter = urlgrabber.progress.BaseMeter()
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m = None
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if hashlib:
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if "sha256" in self.csum:
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csumvalue = self.csum["sha256"]
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m = hashlib.sha256()
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elif "sha1" in self.csum:
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csumvalue = self.csum["sha1"]
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m = hashlib.sha1()
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else:
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if "sha1" in self.csum:
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csumvalue = self.csum["sha1"]
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m = sha.new()
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if not m:
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return
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meter_ct = 0
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disk_size = os.path.getsize(self.file)
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meter.start(size=disk_size,
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text=_("Checking disk signature for %s" % self.file))
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f = file(self.file)
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while 1:
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chunk = f.read(65536)
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if not chunk:
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break
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meter.update(meter_ct)
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meter_ct = meter_ct + 65536
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m.update(chunk)
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checksum = m.hexdigest()
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if checksum != csumvalue:
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logging.debug(_("Disk signature for %s does not match "
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"Expected: %s Received: %s" % (self.file,
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csumvalue, checksum)))
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raise ValueError(_("Disk signature for %s does not "
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"match" % self.file))
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def validate(cond, msg):
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if not cond:
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raise RuntimeError(msg)
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def xpathString(node, path, default=None):
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result = node.xpathEval("string(%s)" % path)
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if len(result) == 0:
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result = default
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return result
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def parse(xml, filename):
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"""Parse the XML description of a VM image into a data structure. Returns
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an object of class Image. BASE should be the directory where the disk
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image files for this image can be found"""
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def cb(x):
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return Image(x, filename=filename)
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return util.parse_node_helper(xml, "image", cb, RuntimeError)
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def parse_file(filename):
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f = open(filename, "r")
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xml = f.read()
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f.close()
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return parse(xml, filename=filename)
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