101 lines
2.8 KiB
Python
101 lines
2.8 KiB
Python
# Copyright (c) 2015 SUSE Linux GmbH. All rights reserved.
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#
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# This file is part of kiwi.
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#
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# kiwi is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# kiwi is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with kiwi. If not, see <http://www.gnu.org/licenses/>
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#
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import os
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# project
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from ..command import Command
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from .device_provider import DeviceProvider
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from ..logger import log
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from ..exceptions import (
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KiwiLoopSetupError
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)
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class LoopDevice(DeviceProvider):
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"""
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Create and manage loop device file for block operations
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Attributes
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* :attr:`node_name`
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loop device node name
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* :attr:`filename`
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loop file name to create
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* :attr:`filesize_mbytes`
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size of the loop file
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* :attr:`blocksize_bytes`
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blocksize used in loop driver
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"""
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def __init__(self, filename, filesize_mbytes=None, blocksize_bytes=None):
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self.node_name = None
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if not os.path.exists(filename) and not filesize_mbytes:
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raise KiwiLoopSetupError(
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'Can not create loop file without a size'
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)
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self.filename = filename
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self.filesize_mbytes = filesize_mbytes
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self.blocksize_bytes = blocksize_bytes
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def get_device(self):
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"""
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Device node name
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:return: device node name
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:rtype: string
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"""
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return self.node_name
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def is_loop(self):
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"""
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Always True
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:rtype: bool
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"""
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return True
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def create(self):
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"""
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Setup a loop device of the specified size and blocksize
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"""
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qemu_img_size = format(self.filesize_mbytes) + 'M'
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Command.run(
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['qemu-img', 'create', self.filename, qemu_img_size]
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)
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loop_options = []
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if self.blocksize_bytes and self.blocksize_bytes != 512:
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loop_options.append('-L')
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loop_options.append(format(self.blocksize_bytes))
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loop_call = Command.run(
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['losetup'] + loop_options + ['-f', '--show', self.filename]
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)
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self.node_name = loop_call.output.rstrip('\n')
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def __del__(self):
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if self.node_name:
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log.info('Cleaning up %s instance', type(self).__name__)
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try:
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Command.run(['losetup', '-d', self.node_name])
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except Exception:
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log.warning(
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'loop device %s still busy', self.node_name
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)
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