virt-manager/virtinst/util.py
Cole Robinson 7a2caee6e1 VirtualConnection: Allow using virt-manager object caches
So when we call into virtinst it doesn't do a whole round of object
lookup and XML fetching.
2013-07-07 18:54:08 -04:00

554 lines
15 KiB
Python

#
# Copyright 2006, 2013 Red Hat, Inc.
# Jeremy Katz <katzj@redhat.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA 02110-1301 USA.
#
import logging
import os
import random
import re
import stat
import libvirt
import libxml2
def listify(l):
if l is None:
return []
elif type(l) != list:
return [l]
else:
return l
def stat_disk(path):
"""Returns the tuple (isreg, size)."""
if not os.path.exists(path):
return True, 0
mode = os.stat(path)[stat.ST_MODE]
# os.path.getsize('/dev/..') can be zero on some platforms
if stat.S_ISBLK(mode):
try:
fd = os.open(path, os.O_RDONLY)
# os.SEEK_END is not present on all systems
size = os.lseek(fd, 0, 2)
os.close(fd)
except:
size = 0
return False, size
elif stat.S_ISREG(mode):
return True, os.path.getsize(path)
return True, 0
def blkdev_size(path):
"""Return the size of the block device. We can't use os.stat() as
that returns zero on many platforms."""
fd = os.open(path, os.O_RDONLY)
# os.SEEK_END is not present on all systems
size = os.lseek(fd, 0, 2)
os.close(fd)
return size
def sanitize_arch(arch):
"""Ensure passed architecture string is the format we expect it.
Returns the sanitized result"""
if not arch:
return arch
tmparch = arch.lower().strip()
if re.match(r'i[3-9]86', tmparch):
return "i686"
elif tmparch == "amd64":
return "x86_64"
return arch
def vm_uuid_collision(conn, uuid):
"""
Check if passed UUID string is in use by another guest of the connection
Returns true/false
"""
return libvirt_collision(conn.lookupByUUIDString, uuid)
def libvirt_collision(collision_cb, val):
"""
Run the passed collision function with val as the only argument:
If libvirtError is raised, return False
If no libvirtError raised, return True
"""
check = False
if val is not None:
try:
if collision_cb(val) is not None:
check = True
except libvirt.libvirtError:
pass
return check
def validate_uuid(val):
if type(val) is not str:
raise ValueError(_("UUID must be a string."))
form = re.match("[a-fA-F0-9]{8}[-]([a-fA-F0-9]{4}[-]){3}[a-fA-F0-9]{12}$",
val)
if form is None:
form = re.match("[a-fA-F0-9]{32}$", val)
if form is None:
raise ValueError(
_("UUID must be a 32-digit hexadecimal number. It may take "
"the form xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx or may "
"omit hyphens altogether."))
else: # UUID had no dashes, so add them in
val = (val[0:8] + "-" + val[8:12] + "-" + val[12:16] +
"-" + val[16:20] + "-" + val[20:32])
return val
def validate_name(name_type, val, lencheck=False):
if type(val) is not str or len(val) == 0:
raise ValueError(_("%s name must be a string") % name_type)
if lencheck:
if len(val) > 50:
raise ValueError(_("%s name must be less than 50 characters") %
name_type)
if re.match("^[0-9]+$", val):
raise ValueError(_("%s name can not be only numeric characters") %
name_type)
if re.match("^[a-zA-Z0-9._-]+$", val) is None:
raise ValueError(_("%s name can only contain alphanumeric, '_', '.', "
"or '-' characters") % name_type)
def validate_macaddr(val):
if val is None:
return
if type(val) is not str:
raise ValueError(_("MAC address must be a string."))
form = re.match("^([0-9a-fA-F]{1,2}:){5}[0-9a-fA-F]{1,2}$", val)
if form is None:
raise ValueError(_("MAC address must be of the format "
"AA:BB:CC:DD:EE:FF"))
def xml_append(orig, new):
"""
Little function that helps generate consistent xml
"""
if not new:
return orig
if orig:
orig += "\n"
return orig + new
def set_xml_path(xml, path, newval):
"""
Set the passed xml xpath to the new value
"""
doc = None
ctx = None
result = None
try:
doc = libxml2.parseDoc(xml)
ctx = doc.xpathNewContext()
ret = ctx.xpathEval(path)
if ret is not None:
if type(ret) == list:
if len(ret) == 1:
ret[0].setContent(newval)
else:
ret.setContent(newval)
result = doc.serialize()
finally:
if doc:
doc.freeDoc()
if ctx:
ctx.xpathFreeContext()
return result
def generate_name(base, collision_cb, suffix="", lib_collision=True,
start_num=0, sep="-", force_num=False, collidelist=None):
"""
Generate a new name from the passed base string, verifying it doesn't
collide with the collision callback.
This can be used to generate disk path names from the parent VM or pool
name. Names generated look like 'base-#suffix', ex:
If foobar, and foobar-1.img already exist, and:
base = "foobar"
suffix = ".img"
output = "foobar-2.img"
@param base: The base string to use for the name (e.g. "my-orig-vm-clone")
@param collision_cb: A callback function to check for collision,
receives the generated name as its only arg
@param lib_collision: If true, the collision_cb is not a boolean function,
and instead throws a libvirt error on failure
@param start_num: The number to start at for generating non colliding names
@param sep: The seperator to use between the basename and the generated number
(default is "-")
@param force_num: Force the generated name to always end with a number
@param collidelist: An extra list of names to check for collision
"""
collidelist = collidelist or []
def collide(n):
if n in collidelist:
return True
if lib_collision:
return libvirt_collision(collision_cb, tryname)
else:
return collision_cb(tryname)
for i in range(start_num, start_num + 100000):
tryname = base
if i != 0 or force_num:
tryname += ("%s%d" % (sep, i))
tryname += suffix
if not collide(tryname):
return tryname
raise ValueError(_("Name generation range exceeded."))
def default_bridge(conn):
if conn.is_remote():
return None
dev = default_route()
if not dev:
return None
# New style peth0 == phys dev, eth0 == bridge, eth0 == default route
if os.path.exists("/sys/class/net/%s/bridge" % dev):
return ["bridge", dev]
# Old style, peth0 == phys dev, eth0 == netloop, xenbr0 == bridge,
# vif0.0 == netloop enslaved, eth0 == default route
try:
defn = int(dev[-1])
except:
defn = -1
if (defn >= 0 and
os.path.exists("/sys/class/net/peth%d/brport" % defn) and
os.path.exists("/sys/class/net/xenbr%d/bridge" % defn)):
return ["bridge", "xenbr%d" % defn]
return None
def parse_node_helper(xml, root_name, callback, exec_class=ValueError):
"""
Parse the passed XML, expecting root as root_name, and pass the
root node to callback
"""
class ErrorHandler:
def __init__(self):
self.msg = ""
def handler(self, ignore, s):
self.msg += s
error = ErrorHandler()
libxml2.registerErrorHandler(error.handler, None)
try:
try:
doc = libxml2.readMemory(xml, len(xml),
None, None,
libxml2.XML_PARSE_NOBLANKS)
except (libxml2.parserError, libxml2.treeError), e:
raise exec_class("%s\n%s" % (e, error.msg))
finally:
libxml2.registerErrorHandler(None, None)
ret = None
try:
root = doc.getRootElement()
if root.name != root_name:
raise ValueError("Root element is not '%s'" % root_name)
ret = callback(root)
finally:
doc.freeDoc()
return ret
def generate_uuid(conn):
for ignore in range(256):
uuid = randomUUID(conn=conn)
if not vm_uuid_collision(conn, uuid):
return uuid
logging.error("Failed to generate non-conflicting UUID")
def default_route():
route_file = "/proc/net/route"
d = file(route_file)
defn = 0
for line in d.xreadlines():
info = line.split()
if (len(info) != 11): # 11 = typical num of fields in the file
logging.warn(_("Invalid line length while parsing %s."),
route_file)
logging.warn(_("Defaulting bridge to xenbr%d"), defn)
break
try:
route = int(info[1], 16)
if route == 0:
return info[0]
except ValueError:
continue
return None
def default_network(conn):
ret = default_bridge(conn)
if not ret:
# FIXME: Check that this exists
ret = ["network", "default"]
return ret
def is_blktap_capable(conn):
# Ideally we would get this from libvirt capabilities XML
if conn.is_remote():
return False
f = open("/proc/modules")
lines = f.readlines()
f.close()
for line in lines:
if line.startswith("blktap ") or line.startswith("xenblktap "):
return True
return False
def randomMAC(conn):
"""Generate a random MAC address.
00-16-3E allocated to xensource
52-54-00 used by qemu/kvm
The OUI list is available at http://standards.ieee.org/regauth/oui/oui.txt.
The remaining 3 fields are random, with the first bit of the first
random field set 0.
@return: MAC address string
"""
if hasattr(conn, "_virtinst__fake_conn_predictable"):
# Testing hack
return "00:11:22:33:44:55"
ouis = {'xen': [0x00, 0x16, 0x3E], 'qemu': [0x52, 0x54, 0x00]}
try:
oui = ouis[conn.getType().lower()]
except KeyError:
oui = ouis['xen']
mac = oui + [
random.randint(0x00, 0xff),
random.randint(0x00, 0xff),
random.randint(0x00, 0xff)]
return ':'.join(["%02x" % x for x in mac])
def randomUUID(conn):
if hasattr(conn, "_virtinst__fake_conn_predictable"):
# Testing hack
return "00000000-1111-2222-3333-444444444444"
u = [random.randint(0, 255) for ignore in range(0, 16)]
u[7] = (u[7] & 0x0F) | (4 << 4)
u[9] = (u[9] & 0x3F) | (2 << 6)
return "-".join(["%02x" * 4, "%02x" * 2, "%02x" * 2, "%02x" * 2,
"%02x" * 6]) % tuple(u)
def xml_escape(xml):
"""
Replaces chars ' " < > & with xml safe counterparts
"""
if xml is None:
return None
xml = xml.replace("&", "&amp;")
xml = xml.replace("'", "&apos;")
xml = xml.replace("\"", "&quot;")
xml = xml.replace("<", "&lt;")
xml = xml.replace(">", "&gt;")
return xml
def get_xml_path(xml, path=None, func=None):
"""
Return the content from the passed xml xpath, or return the result
of a passed function (receives xpathContext as its only arg)
"""
doc = None
ctx = None
result = None
try:
doc = libxml2.parseDoc(xml)
ctx = doc.xpathNewContext()
if path:
ret = ctx.xpathEval(path)
if ret is not None:
if type(ret) == list:
if len(ret) >= 1:
result = ret[0].content
else:
result = ret
elif func:
result = func(ctx)
else:
raise ValueError(_("'path' or 'func' is required."))
finally:
if doc:
doc.freeDoc()
if ctx:
ctx.xpathFreeContext()
return result
def lookup_pool_by_path(conn, path):
"""
Return the first pool with matching matching target path.
return the first we find, active or inactive. This iterates over
all pools and dumps their xml, so it is NOT quick.
Favor running pools over inactive pools.
@returns: virStoragePool object if found, None otherwise
"""
if not conn.check_conn_support(conn.SUPPORT_CONN_STORAGE):
return None
def check_pool(pool, path):
xml_path = get_xml_path(pool.get_xml(refresh_if_nec=False),
"/pool/target/path")
if xml_path is not None and os.path.abspath(xml_path) == path:
return pool
for pool in conn.fetch_all_pools():
p = check_pool(pool, path)
if p:
return p.get_backend()
return None
def uri_split(uri):
"""
Parse a libvirt hypervisor uri into it's individual parts
@returns: tuple of the form (scheme (ex. 'qemu', 'xen+ssh'), username,
hostname, path (ex. '/system'), query,
fragment)
"""
def splitnetloc(url, start=0):
for c in '/?#': # the order is important!
delim = url.find(c, start)
if delim >= 0:
break
else:
delim = len(url)
return url[start:delim], url[delim:]
username = netloc = query = fragment = ''
i = uri.find(":")
if i > 0:
scheme, uri = uri[:i].lower(), uri[i + 1:]
if uri[:2] == '//':
netloc, uri = splitnetloc(uri, 2)
offset = netloc.find("@")
if offset > 0:
username = netloc[0:offset]
netloc = netloc[offset + 1:]
if '#' in uri:
uri, fragment = uri.split('#', 1)
if '?' in uri:
uri, query = uri.split('?', 1)
else:
scheme = uri.lower()
return scheme, username, netloc, uri, query, fragment
def is_error_nosupport(err):
"""
Check if passed exception indicates that the called libvirt command isn't
supported
@param err: Exception raised from command call
@returns: True if command isn't supported, False if we can't determine
"""
if not isinstance(err, libvirt.libvirtError):
return False
if (err.get_error_code() == libvirt.VIR_ERR_RPC or
err.get_error_code() == libvirt.VIR_ERR_NO_SUPPORT):
return True
return False
def local_libvirt_version():
"""
Lookup the local libvirt library version, but cache the value since
it never changes.
"""
key = "__virtinst_cached_getVersion"
if not hasattr(libvirt, key):
setattr(libvirt, key, libvirt.getVersion())
return getattr(libvirt, key)
def uuidstr(rawuuid):
hx = ['0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f']
uuid = []
for i in range(16):
uuid.append(hx[((ord(rawuuid[i]) >> 4) & 0xf)])
uuid.append(hx[(ord(rawuuid[i]) & 0xf)])
if i == 3 or i == 5 or i == 7 or i == 9:
uuid.append('-')
return "".join(uuid)