diskimage-builder/diskimage_builder/block_device/level0/localloop.py
Ian Wienand 9a8b135267 Don't make image & loopdev functions static
You can't pickle a static method reference which complicates being
able to save the node graph when the "rollback" call-back wants to
hold references to these functions.  The outer module (localoop.py) is
small anyway, so from an organisation point of view the difference is
minimal.  Since these are really only called with parameters from the
containing class, they could be class methods with no parameters, at
the small expense of having to fiddle the mbr test-case a bit.

Change-Id: I6f9592a4295abe1b41294b79828bc2f3c2da01c6
2017-06-08 17:10:10 +10:00

139 lines
4.7 KiB
Python

# Copyright 2016 Andreas Florath (andreas@florath.net)
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
import os
import subprocess
from diskimage_builder.block_device.exception import \
BlockDeviceSetupException
from diskimage_builder.block_device.plugin import NodeBase
from diskimage_builder.block_device.plugin import PluginBase
from diskimage_builder.block_device.utils import parse_abs_size_spec
logger = logging.getLogger(__name__)
def image_create(filename, size):
logger.info("Create image file [%s]", filename)
with open(filename, "w") as fd:
fd.seek(size - 1)
fd.write("\0")
def image_delete(filename):
logger.info("Remove image file [%s]", filename)
os.remove(filename)
def loopdev_attach(filename):
logger.info("loopdev attach")
logger.debug("Calling [sudo losetup --show -f %s]", filename)
subp = subprocess.Popen(["sudo", "losetup", "--show", "-f",
filename], stdout=subprocess.PIPE)
rval = subp.wait()
if rval == 0:
# [:-1]: Cut of the newline
block_device = subp.stdout.read()[:-1].decode("utf-8")
logger.info("New block device [%s]", block_device)
return block_device
else:
logger.error("losetup failed")
raise BlockDeviceSetupException("losetup failed")
def loopdev_detach(loopdev):
logger.info("loopdev detach")
# loopback dev may be tied up a bit by udev events triggered
# by partition events
for try_cnt in range(10, 1, -1):
logger.debug("Calling [sudo losetup -d %s]", loopdev)
subp = subprocess.Popen(["sudo", "losetup", "-d",
loopdev])
rval = subp.wait()
if rval == 0:
logger.info("Successfully detached [%s]", loopdev)
return 0
else:
logger.error("loopdev detach failed")
# Do not raise an error - maybe other cleanup methods
# can at least do some more work.
logger.debug("Gave up trying to detach [%s]", loopdev)
return rval
class LocalLoopNode(NodeBase):
"""Level0: Local loop image device handling.
This class handles local loop devices that can be used
for VM image installation.
"""
def __init__(self, config, default_config):
logger.debug("Creating LocalLoop object; config [%s] "
"default_config [%s]", config, default_config)
super(LocalLoopNode, self).__init__(config['name'])
if 'size' in config:
self.size = parse_abs_size_spec(config['size'])
logger.debug("Image size [%s]", self.size)
else:
self.size = parse_abs_size_spec(default_config['image-size'])
logger.debug("Using default image size [%s]", self.size)
if 'directory' in config:
self.image_dir = config['directory']
else:
self.image_dir = default_config['image-dir']
self.filename = os.path.join(self.image_dir, self.name + ".raw")
def get_edges(self):
"""Because this is created without base, there are no edges."""
return ([], [])
def create(self, state, rollback):
logger.debug("[%s] Creating loop on [%s] with size [%d]",
self.name, self.filename, self.size)
rollback.append(lambda: image_delete(self.filename))
image_create(self.filename, self.size)
block_device = loopdev_attach(self.filename)
rollback.append(lambda: loopdev_detach(block_device))
if 'blockdev' not in state:
state['blockdev'] = {}
state['blockdev'][self.name] = {"device": block_device,
"image": self.filename}
logger.debug("Created loop name [%s] device [%s] image [%s]",
self.name, block_device, self.filename)
return
def umount(self, state):
loopdev_detach(state['blockdev'][self.name]['device'])
def cleanup(self, state):
pass
def delete(self, state):
image_delete(state['blockdev'][self.name]['image'])
class LocalLoop(PluginBase):
def __init__(self, config, defaults):
super(LocalLoop, self).__init__()
self.node = LocalLoopNode(config, defaults)
def get_nodes(self):
return [self.node]