3d48a528c1
Block device handling can be somewhat complex - especially when taking things like md, lvm or encryption into account. This patch factors out the creation and deletion of the local loop image device handling into a python library. The main propose of this patch is to implement the needed infrastructure. Based on this, more advanced functions can be added. Example: (advanced) partitioning, LVM, handling different boot scenarios (BIOS, UEFI, ...), possibility of handling multiple images (local loop image, iSCSI, physical hard disk, ...), handling of different filesystems for different partitions / LVs. Change-Id: Ib626b36a00f8a5dc3dbde8df3e2619a2438eaaf1 Signed-off-by: Andreas Florath <andreas@florath.net>
93 lines
3.3 KiB
Python
93 lines
3.3 KiB
Python
# Copyright 2016 Andreas Florath (andreas@florath.net)
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from diskimage_builder.block_device.utils import parse_abs_size_spec
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import logging
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import os
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import subprocess
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import sys
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import time
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logger = logging.getLogger(__name__)
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class LocalLoop(object):
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"""Level0: Local loop image device handling.
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This class handles local loop devices that can be used
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for VM image installation.
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"""
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type_string = "local_loop"
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def __init__(self, config, default_config, result=None):
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if 'size' in config:
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self.size = parse_abs_size_spec(config['size'])
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logger.debug("Image size [%s]" % self.size)
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else:
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self.size = parse_abs_size_spec(default_config['image_size'])
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logger.debug("Using default image size [%s]" % self.size)
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if 'directory' in config:
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self.image_dir = config['directory']
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else:
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self.image_dir = default_config['image_dir']
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self.name = config['name']
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self.filename = os.path.join(self.image_dir, self.name + ".raw")
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self.result = result
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if self.result is not None:
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self.block_device = self.result[self.name]['device']
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def create(self):
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logger.debug("[%s] Creating loop on [%s] with size [%d]" %
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(self.name, self.filename, self.size))
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with open(self.filename, "w") as fd:
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fd.seek(self.size - 1)
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fd.write("\0")
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logger.debug("Calling [sudo losetup --show -f %s]"
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% self.filename)
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subp = subprocess.Popen(["sudo", "losetup", "--show", "-f",
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self.filename], stdout=subprocess.PIPE)
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rval = subp.wait()
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if rval == 0:
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# [:-1]: Cut of the newline
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self.block_device = subp.stdout.read()[:-1]
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logger.debug("New block device [%s]" % self.block_device)
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else:
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logger.error("losetup failed")
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sys.exit(1)
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return {self.name: {"device": self.block_device,
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"image": self.filename}}
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def delete(self):
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# loopback dev may be tied up a bit by udev events triggered
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# by partition events
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for try_cnt in range(10, 1, -1):
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logger.debug("Delete loop [%s]" % self.block_device)
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res = subprocess.call("sudo losetup -d %s" %
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(self.block_device),
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shell=True)
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if res == 0:
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return {self.name: True}
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logger.debug("[%s] may be busy, sleeping [%d] more secs"
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% (self.block_device, try_cnt))
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time.sleep(1)
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logger.debug("Gave up trying to detach [%s]" %
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self.block_device)
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return {self.name: False}
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