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import logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger('anate.devices')
import os
import stat
import pwd
import grp
import tempfile
from baseutils import Subprocess
def getDeviceNumbers(path):
try:
statinfo = os.stat(path)
except OSError:
return (None, None)
return (os.major(statinfo.st_rdev), os.minor(statinfo.st_rdev))
class BlockDeviceNode(object):
def __init__(self, path, major, minor):
self._path = path
self._major = major
self._minor = minor
def create(self, mode=0660, owner='root', group='disk'):
try:
os.mknod(self.path, mode | stat.S_IFBLK, os.makedev(self.major, self.minor))
except OSError:
logger.error('unable to create node %s', self.path)
return
try:
uid = pwd.getpwnam(owner)[2]
except KeyError:
logger.warning('user %s does not exist, not changing the owner', owner)
uid = -1
try:
gid = grp.getgrnam(group)[2]
except KeyError:
logger.warning('group %s does not exist, not changing the group', group)
gid = -1
try:
os.chown(self.path, uid, gid)
except OSError:
logger.warning('unable to change the owner and group of node %s', self.path)
def unlink(self):
try:
os.unlink(self.path)
except OSError:
logger.error('unable to unlink node %s', self.path)
@property
def path(self):
return self._path
@property
def major(self):
return self._major
@major.setter
def major(self, value):
self._major = value
@property
def minor(self):
return self._minor
@minor.setter
def minor(self, value):
self._minor = value
@property
def available(self):
return os.access(self.path, os.R_OK | os.W_OK)
class BlockDevice(object):
def __init__(self, name, node):
if not isinstance(node, BlockDeviceNode):
raise TypeError, 'node must be an instance of BlockDeviceNode, got %s' % type(node)
self._name = name
self._node = node
self._active = False
def initialize(self):
self._active = True
def destroy(self):
self._active = False
@property
def name(self):
return self._name
@property
def path(self):
return self._node.path
@property
def major(self):
return self._node.major
@property
def minor(self):
return self._node.minor
@property
def active(self):
return self._active
class StorageDevice(BlockDevice):
def __init__(self, name, node, size=0):
BlockDevice.__init__(self, name, node)
self._size = size
@property
def size(self):
return self._size
class LoopDevice(StorageDevice):
def __init__(self, name, node, destination_file, size):
StorageDevice.__init__(self, name, node, size)
self._file = destination_file
def initialize(self):
proc = Subprocess('dd', 'if=/dev/zero', 'of=%s' % self._file, 'bs=1k', 'seek=%d' % (self.size * 1024 - 1), 'count=1')
proc.run()
if proc.rc:
logger.error('%s', proc.stderr)
raise OSError, 'dd failed when creating file %s' % self._file
proc = Subprocess('losetup', self.path, self._file)
proc.run()
if proc.rc:
logger.error('%s', proc.stderr)
raise OSError, 'losetup failed when setting up loop device %s' % self.path
self._active = True
def destroy(self):
proc = Subprocess('losetup', '-d', self.path)
proc.run()
if proc.rc:
logger.error('%s', proc.stderr)
raise OSError, 'losetup failed when removing loop device %s' % self.path
os.unlink(self._file)
self._active = False
class DMDevice(StorageDevice):
_DM_DEVICES_ROOT_PATH = '/dev/mapper/'
_SECTORS_PER_MB = 2048
def __init__(self, name, destination_device, size=None):
if not isinstance(destination_device, StorageDevice):
raise TypeError, 'destination_device must be an instance of StorageDevice, got %s' % type(destination_device)
if not destination_device.active:
destination_device.initialize()
usable_size = destination_device.size
if not size:
size = usable_size
elif size > usable_size:
logger.warning('creating dm device which is bigger than the destination device')
else:
usable_size = size
node = BlockDeviceNode(os.path.join(self._DM_DEVICES_ROOT_PATH, name), major=None, minor=None)
StorageDevice.__init__(self, name, node, size)
self._destination_device = destination_device
self._usable_size = usable_size
def initialize(self):
table_file = tempfile.NamedTemporaryFile()
map = {'logical_start_sector': 0,
'num_sectors': self.usable_size * self._SECTORS_PER_MB,
'target_type': 'linear',
'destination_device': self._destination_device.path,
'destination_device_start_sector': 0}
string = '%(logical_start_sector)d %(num_sectors)d %(target_type)s %(destination_device)s %(destination_device_start_sector)d\n' % map
table_file.write(string)
table_file.flush()
logger.info('table_file: %s', string.strip())
if self.size > self.usable_size:
map = {'logical_start_sector': self.usable_size * self._SECTORS_PER_MB,
'num_sectors': (self.size - self.usable_size) * self._SECTORS_PER_MB,
'target_type': 'zero'}
string = '%(logical_start_sector)d %(num_sectors)d %(target_type)s\n' % map
table_file.write(string)
table_file.flush()
logger.info('table_file: %s', string.strip())
proc = Subprocess('dmsetup', 'create', self.name, table_file.name)
proc.run()
table_file.close()
if proc.rc:
logger.error('%s', proc.stderr)
raise OSError, 'dmsetup failed when setting up dm device %s' % self.name
major, minor = getDeviceNumbers(self._node.path)
self._node.major = major
self._node.minor = minor
self._active = True
def destroy(self):
proc = Subprocess('dmsetup', 'remove', '--force', self.name)
proc.run()
if proc.rc:
logger.error('%s', proc.stderr)
raise OSError, 'dmsetup failed when removing dm device %s' % self.name
self._active = False
@property
def usable_size(self):
return self._usable_size
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