virt-manager/virtinst/diskbackend.py

803 lines
24 KiB
Python

#
# Storage lookup/creation helpers
#
# Copyright 2013 Red Hat, Inc.
#
# This work is licensed under the GNU GPLv2 or later.
# See the COPYING file in the top-level directory.
import os
import re
import stat
import subprocess
import libvirt
from .logger import log
from .storage import StoragePool, StorageVolume
from . import xmlutil
def _lookup_vol_by_path(conn, path):
"""
Try to find a volume matching the full passed path. Call info() on
it to ensure the volume wasn't removed behind libvirt's back
"""
try:
vol = conn.storageVolLookupByPath(path)
vol.info()
return vol, None
except libvirt.libvirtError as e:
# test_urls trigger empty errors here, because python
# garbage collection kicks in after the failure but before
# we read the error code, and libvirt virStoragePoolFree
# public entry point clears the cached error. So ignore
# an empty error code
if (e.get_error_code() and
e.get_error_code() != libvirt.VIR_ERR_NO_STORAGE_VOL):
raise # pragma: no cover
return None, e
def _lookup_vol_by_basename(pool, path):
"""
Try to lookup a volume for 'path' in parent 'pool' by it's filename.
This sometimes works in cases where full volume path lookup doesn't,
since not all libvirt storage backends implement path lookup.
"""
name = os.path.basename(path)
if name in pool.listVolumes():
return pool.storageVolLookupByName(name)
def _get_block_size(path): # pragma: no cover
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 Exception:
size = 0
return size
def _get_size(path):
if not os.path.exists(path):
return 0
if _stat_is_block(path):
return _get_block_size(path) # pragma: no cover
return os.path.getsize(path)
def _stat_is_block(path):
if not os.path.exists(path):
return False
return stat.S_ISBLK(os.stat(path)[stat.ST_MODE])
def _check_if_path_managed(conn, path):
"""
Try to lookup storage objects for the passed path.
Returns (volume, parent pool). Only one is returned at a time.
"""
vol, ignore = _lookup_vol_by_path(conn, path)
if vol:
return vol, vol.storagePoolLookupByVolume()
pool = StoragePool.lookup_pool_by_path(conn, os.path.dirname(path))
if not pool:
return None, None
# We have the parent pool, but didn't find a volume on first lookup
# attempt. Refresh the pool and try again, in case we were just out
# of date or the pool was inactive.
try:
StoragePool.ensure_pool_is_running(pool, refresh=True)
vol, verr = _lookup_vol_by_path(conn, path)
if verr:
try:
vol = _lookup_vol_by_basename(pool, path)
except Exception: # pragma: no cover
pass
except Exception as e: # pragma: no cover
vol = None
pool = None
verr = str(e)
if not vol and not pool and verr: # pragma: no cover
raise ValueError(_("Cannot use storage %(path)s: %(err)s") %
{'path': path, 'err': verr})
return vol, pool
def _can_auto_manage(path):
path = path or ""
skip_prefixes = ["/dev", "/sys", "/proc"]
if path_is_url(path):
return False
for prefix in skip_prefixes:
if path.startswith(prefix + "/") or path == prefix:
return False
return True
def _get_storage_search_path(path):
# If the passed path is one of our artificial rbd:// style
# URIs, parse out the path component, since that is what is needed
# for looking up storage volumes by target path
from .uri import URI
uriobj = URI(path)
if uriobj.scheme == "rbd":
return uriobj.path.strip("/")
return path
def manage_path(conn, path):
"""
If path is not managed, try to create a storage pool to probe the path
"""
if not conn.support.conn_storage():
return None, None # pragma: no cover
if not path:
return None, None
if not path_is_url(path) and not path_is_network_vol(conn, path):
path = os.path.abspath(path)
searchpath = _get_storage_search_path(path)
vol, pool = _check_if_path_managed(conn, searchpath)
if vol or pool or not _can_auto_manage(path):
return vol, pool
dirname = os.path.dirname(path)
poolname = os.path.basename(dirname).replace(" ", "_")
if not poolname:
poolname = "dirpool"
poolname = StoragePool.find_free_name(conn, poolname)
log.debug("Attempting to build pool=%s target=%s", poolname, dirname)
poolxml = StoragePool(conn)
poolxml.name = poolname
poolxml.type = poolxml.TYPE_DIR
poolxml.target_path = dirname
pool = poolxml.install(build=False, create=True, autostart=True)
vol = _lookup_vol_by_basename(pool, path)
return vol, pool
def path_is_url(path):
"""
Detect if path is a URL
"""
return bool(re.match(r"[a-zA-Z]+(\+[a-zA-Z]+)?://.*", path or ""))
def path_is_network_vol(conn, path):
"""
Detect if path is a network volume such as rbd, gluster, etc
"""
for volxml in conn.fetch_all_vols():
if path and volxml.target_path == path:
return volxml.type == "network"
return False
def _get_dev_type(path, vol_xml, vol_object, pool_xml, remote):
"""
Try to get device type for volume.
"""
if vol_xml and vol_xml.type:
return vol_xml.type
if pool_xml:
t = pool_xml.get_disk_type()
if t == StorageVolume.TYPE_BLOCK:
return "block"
elif t == StorageVolume.TYPE_NETWORK:
return "network"
if vol_object: # pragma: no cover
# This path is hard to test, because test suite XML always has
# the vol_xml.type set
t = vol_object.info()[0]
if t == StorageVolume.TYPE_FILE:
return "file"
elif t == StorageVolume.TYPE_BLOCK:
return "block"
elif t == StorageVolume.TYPE_NETWORK:
return "network"
if path:
if path_is_url(path):
return "network"
if remote:
if not _can_auto_manage(path):
# Just a heurisitic, if this path is one of the ones
# we don't try to auto-import, then consider it a
# block device, because managing those correctly is difficult
return "block"
else:
if os.path.isdir(path):
return "dir"
elif _stat_is_block(path):
return "block" # pragma: no cover
return "file"
def path_definitely_exists(conn, path):
"""
Return True if the path certainly exists, False if we are unsure.
See DeviceDisk entry point for more details
"""
if path is None:
return False
try:
(vol, pool) = _check_if_path_managed(conn, path)
ignore = pool
if vol:
return True
if not conn.is_remote():
return os.path.exists(path)
except Exception: # pragma: no cover
pass
return False
#########################
# ACL/path perm helpers #
#########################
SETFACL = "setfacl"
def _fix_perms_acl(dirname, username):
cmd = [SETFACL, "--modify", "user:%s:x" % username, dirname]
proc = subprocess.Popen(cmd,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
out, err = proc.communicate()
log.debug("Ran command '%s'", cmd)
if out or err:
log.debug("out=%s\nerr=%s", out, err)
if proc.returncode != 0:
raise ValueError(err)
def _fix_perms_chmod(dirname):
log.debug("Setting +x on %s", dirname)
mode = os.stat(dirname).st_mode
newmode = mode | stat.S_IXOTH
os.chmod(dirname, newmode)
if os.stat(dirname).st_mode != newmode:
# Trying to change perms on vfat at least doesn't work
# but also doesn't seem to error. Try and detect that
raise ValueError( # pragma: no cover
_("Permissions on '%s' did not stick") % dirname)
def set_dirs_searchable(dirlist, username):
useacl = True
errdict = {}
for dirname in dirlist:
if useacl:
try:
_fix_perms_acl(dirname, username)
continue
except Exception as e:
log.debug("setfacl failed: %s", e)
log.debug("trying chmod")
useacl = False
try:
# If we reach here, ACL setting failed, try chmod
_fix_perms_chmod(dirname)
except Exception as e: # pragma: no cover
errdict[dirname] = str(e)
return errdict
def _is_dir_searchable(dirname, uid, username):
"""
Check if passed directory is searchable by uid
"""
try:
statinfo = os.stat(dirname)
except OSError: # pragma: no cover
return False
if uid == statinfo.st_uid:
flag = stat.S_IXUSR
elif uid == statinfo.st_gid:
flag = stat.S_IXGRP # pragma: no cover
else:
flag = stat.S_IXOTH
if bool(statinfo.st_mode & flag):
return True
# Check POSIX ACL (since that is what we use to 'fix' access)
cmd = ["getfacl", dirname]
try:
proc = subprocess.Popen(cmd,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
out, err = proc.communicate()
except OSError: # pragma: no cover
log.debug("Didn't find the getfacl command.")
return False
if proc.returncode != 0: # pragma: no cover
log.debug("Cmd '%s' failed: %s", cmd, err)
return False
pattern = "user:%s:..x" % username
return bool(re.search(pattern.encode("utf-8", "replace"), out))
def is_path_searchable(path, uid, username):
"""
Check each dir component of the passed path, see if they are
searchable by the uid/username, and return a list of paths
which aren't searchable
"""
if os.path.isdir(path):
dirname = path
base = "-"
else:
dirname, base = os.path.split(path)
fixlist = []
while base:
if not _is_dir_searchable(dirname, uid, username):
fixlist.append(dirname)
dirname, base = os.path.split(dirname)
return fixlist
##############################################
# Classes for tracking storage media details #
##############################################
class _StorageBase(object):
"""
Storage base class, defining the API used by DeviceDisk
"""
def __init__(self, conn):
self._conn = conn
self._parent_pool_xml = None
def get_size(self):
raise NotImplementedError()
def get_dev_type(self):
raise NotImplementedError()
def get_driver_type(self):
raise NotImplementedError()
def get_vol_install(self):
raise NotImplementedError()
def get_vol_object(self):
raise NotImplementedError()
def get_parent_pool(self):
raise NotImplementedError()
def get_parent_pool_xml(self):
if not self._parent_pool_xml and self.get_parent_pool():
self._parent_pool_xml = StoragePool(self._conn,
parsexml=self.get_parent_pool().XMLDesc(0))
return self._parent_pool_xml
def validate(self):
raise NotImplementedError()
def get_path(self):
raise NotImplementedError()
def is_stub(self):
return False
# Storage creation routines
def is_size_conflict(self):
raise NotImplementedError()
def will_create_storage(self):
raise NotImplementedError()
def create(self, meter):
ignore = meter # pragma: no cover
raise xmlutil.DevError(
"%s can't create storage" % self.__class__.__name__)
class _StorageCreator(_StorageBase):
"""
Base object for classes that will actually create storage on disk
"""
def __init__(self, conn):
_StorageBase.__init__(self, conn)
self._pool = None
self._vol_install = None
self._path = None
self._size = None
self._dev_type = None
##############
# Public API #
##############
def create(self, meter):
raise NotImplementedError
def validate(self):
raise NotImplementedError
def get_size(self):
raise NotImplementedError
def get_path(self):
if self._vol_install and not self._path:
xmlobj = StoragePool(self._conn,
parsexml=self._vol_install.pool.XMLDesc(0))
if self.get_dev_type() == "network":
self._path = self._vol_install.name
else:
self._path = os.path.join(
xmlobj.target_path, self._vol_install.name)
return self._path
def get_vol_install(self):
return self._vol_install
def get_vol_xml(self):
return self._vol_install
def get_dev_type(self):
if not self._dev_type:
self._dev_type = _get_dev_type(self._path, self._vol_install, None,
self.get_parent_pool_xml(),
self._conn.is_remote())
return self._dev_type
def get_driver_type(self):
if self._vol_install:
if self._vol_install.supports_format():
return self._vol_install.format
return "raw"
def will_create_storage(self):
return True
def get_vol_object(self):
return None
def get_parent_pool(self):
if self._vol_install:
return self._vol_install.pool
return None
def exists(self):
return False
class ManagedStorageCreator(_StorageCreator):
"""
Handles storage creation via libvirt APIs. All the actual creation
logic lives in StorageVolume, this is mostly about pulling out bits
from that class and mapping them to DeviceDisk elements
"""
def __init__(self, conn, vol_install):
_StorageCreator.__init__(self, conn)
self._pool = vol_install.pool
self._vol_install = vol_install
def create(self, meter):
return self._vol_install.install(meter=meter)
def is_size_conflict(self):
return self._vol_install.is_size_conflict()
def validate(self):
return self._vol_install.validate()
def get_size(self):
return float(self._vol_install.capacity) / 1024.0 / 1024.0 / 1024.0
class CloneStorageCreator(_StorageCreator):
"""
Handles manually copying local files for Cloner
Many clone scenarios will use libvirt storage APIs, which will use
the ManagedStorageCreator
"""
def __init__(self, conn, output_path, input_path, size, sparse):
_StorageCreator.__init__(self, conn)
self._path = output_path
self._output_path = output_path
self._input_path = input_path
self._size = size
self._sparse = sparse
def get_size(self):
return self._size
def is_size_conflict(self):
ret = False
msg = None
if self.get_dev_type() == "block":
avail = _get_size(self._path) # pragma: no cover
else:
vfs = os.statvfs(os.path.dirname(os.path.abspath(self._path)))
avail = vfs.f_frsize * vfs.f_bavail
need = int(self._size) * 1024 * 1024 * 1024
if need > avail: # pragma: no cover
if self._sparse:
msg = _("The filesystem will not have enough free space"
" to fully allocate the sparse file when the guest"
" is running.")
else:
ret = True
msg = _("There is not enough free space to create the disk.")
if msg:
msg += " "
msg += (_("%(mem1)s M requested > %(mem2)s M available") %
{"mem1": (need // (1024 * 1024)),
"mem2": (avail // (1024 * 1024))})
return (ret, msg)
def validate(self):
if self._size is None: # pragma: no cover
raise ValueError(_("size is required for non-existent disk "
"'%s'" % self.get_path()))
err, msg = self.is_size_conflict()
if err:
raise ValueError(msg) # pragma: no cover
if msg:
log.warning(msg) # pragma: no cover
def create(self, meter):
text = (_("Cloning %(srcfile)s") %
{'srcfile': os.path.basename(self._input_path)})
size_bytes = int(self.get_size() * 1024 * 1024 * 1024)
meter.start(text, size_bytes)
# Plain file clone
self._clone_local(meter, size_bytes)
def _clone_local(self, meter, size_bytes):
if self._input_path == "/dev/null": # pragma: no cover
# Not really sure why this check is here,
# but keeping for compat
log.debug("Source dev was /dev/null. Skipping")
return
if self._input_path == self._output_path:
log.debug("Source and destination are the same. Skipping.")
return
# If a destination file exists and sparse flag is True,
# this priority takes an existing file.
if (not os.path.exists(self._output_path) and self._sparse):
clone_block_size = 4096
sparse = True
fd = None
try:
fd = os.open(self._output_path, os.O_WRONLY | os.O_CREAT,
0o640)
os.ftruncate(fd, size_bytes)
finally:
if fd:
os.close(fd)
else:
clone_block_size = 1024 * 1024 * 10
sparse = False
log.debug("Local Cloning %s to %s, sparse=%s, block_size=%s",
self._input_path, self._output_path,
sparse, clone_block_size)
zeros = b'\0' * 4096
src_fd, dst_fd = None, None
try:
try:
src_fd = os.open(self._input_path, os.O_RDONLY)
dst_fd = os.open(self._output_path,
os.O_WRONLY | os.O_CREAT, 0o640)
i = 0
while 1:
l = os.read(src_fd, clone_block_size)
s = len(l)
if s == 0:
meter.end()
break
# check sequence of zeros
if sparse and zeros == l:
os.lseek(dst_fd, s, 1)
else:
b = os.write(dst_fd, l)
if s != b: # pragma: no cover
meter.end()
break
i += s
if i < size_bytes:
meter.update(i)
except OSError as e: # pragma: no cover
log.debug("Error while cloning", exc_info=True)
msg = (_("Error cloning diskimage "
"%(inputpath)s to %(outputpath)s: %(error)s") %
{"inputpath": self._input_path,
"outputpath": self._output_path,
"error": str(e)})
raise RuntimeError(msg) from None
finally:
if src_fd is not None:
os.close(src_fd)
if dst_fd is not None:
os.close(dst_fd)
class StorageBackendStub(_StorageBase):
"""
Class representing a storage path for a parsed XML disk, that we
don't want to do slow resolving of unless requested
"""
def __init__(self, conn, path, dev_type, driver_type):
_StorageBase.__init__(self, conn)
self._path = path
self._dev_type = dev_type
self._driver_type = driver_type
def get_path(self):
return self._path
def get_vol_object(self):
return None
def get_vol_xml(self):
return None
def get_parent_pool(self):
return None
def get_size(self):
return 0
def exists(self):
return True
def get_dev_type(self):
return self._dev_type
def get_driver_type(self):
return self._driver_type
def validate(self):
return
def get_vol_install(self):
return None
def is_size_conflict(self):
return (False, None)
def is_stub(self):
return True
def will_create_storage(self):
return False
class StorageBackend(_StorageBase):
"""
Class that carries all the info about any existing storage that
the disk references
"""
def __init__(self, conn, path, vol_object, parent_pool):
_StorageBase.__init__(self, conn)
self._vol_object = vol_object
self._parent_pool = parent_pool
self._path = path
if self._vol_object is not None:
self._path = None
if self._vol_object and not self._parent_pool:
raise xmlutil.DevError(
"parent_pool must be specified")
# Cached bits
self._vol_xml = None
self._parent_pool_xml = None
self._exists = None
self._size = None
self._dev_type = None
##############
# Public API #
##############
def get_path(self):
if self._vol_object:
return self.get_vol_xml().target_path
return self._path
def get_vol_object(self):
return self._vol_object
def get_vol_xml(self):
if self._vol_xml is None:
self._vol_xml = StorageVolume(self._conn,
parsexml=self._vol_object.XMLDesc(0))
self._vol_xml.pool = self._parent_pool
return self._vol_xml
def get_parent_pool(self):
return self._parent_pool
def get_size(self):
"""
Return size of existing storage
"""
if self._size is None:
ret = 0
if self._vol_object:
ret = self.get_vol_xml().capacity
elif self._path:
ret = _get_size(self._path)
self._size = (float(ret) / 1024.0 / 1024.0 / 1024.0)
return self._size
def exists(self):
if self._exists is None:
if self._vol_object:
self._exists = True
elif self._path is None:
self._exists = True
elif (not self.get_dev_type() == "network" and
not self._conn.is_remote() and
os.path.exists(self._path)):
self._exists = True
elif self._parent_pool:
self._exists = False
elif self.get_dev_type() == "network":
self._exists = True
elif (self._conn.is_remote() and
not _can_auto_manage(self._path)):
# This allows users to pass /dev/sdX and we don't try to
# validate it exists on the remote connection, since
# autopooling /dev is perilous. Libvirt will error if
# the device doesn't exist.
self._exists = True
else:
self._exists = False
return self._exists
def get_dev_type(self):
"""
Return disk 'type' value per storage settings
"""
if self._dev_type is None:
vol_xml = None
if self._vol_object:
vol_xml = self.get_vol_xml()
self._dev_type = _get_dev_type(self._path, vol_xml, self._vol_object,
self.get_parent_pool_xml(),
self._conn.is_remote())
return self._dev_type
def get_driver_type(self):
if self._vol_object:
ret = self.get_vol_xml().format
if ret != "unknown":
return ret
return None
def validate(self):
return
def get_vol_install(self):
return None
def is_size_conflict(self):
return (False, None)
def will_create_storage(self):
return False