2022-02-09 18:22:13 +00:00
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# Copyright 2018-2022 Canonical, Ltd.
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as
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# published by the Free Software Foundation, either version 3 of the
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# License, or (at your option) any later version.
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#
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# This program 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 Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import contextlib
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import datetime
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import grp
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2018-05-24 21:06:09 +00:00
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import os
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import stat
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import tempfile
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2022-02-09 18:22:13 +00:00
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_DEF_PERMS = 0o640
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_DEF_GROUP = 'adm'
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2018-05-24 21:06:09 +00:00
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2022-02-09 18:22:13 +00:00
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@contextlib.contextmanager
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def open_perms(filename, *, cmode=None, omode='w', copy_mode=False):
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if cmode is None:
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cmode = _DEF_PERMS
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2018-05-24 21:06:09 +00:00
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if copy_mode:
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try:
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file_stat = os.stat(filename)
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2022-02-09 18:22:13 +00:00
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cmode = stat.S_IMODE(file_stat.st_mode)
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2018-05-24 21:06:09 +00:00
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except OSError:
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pass
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tf = None
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try:
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2022-02-09 18:22:13 +00:00
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dirname = os.path.dirname(filename)
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os.makedirs(dirname, exist_ok=True)
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tf = tempfile.NamedTemporaryFile(dir=dirname, delete=False, mode=omode)
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yield tf
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2018-05-24 21:06:09 +00:00
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tf.close()
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2022-02-09 18:22:13 +00:00
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os.chmod(tf.name, cmode)
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if os.getuid() == 0:
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os.chown(tf.name, -1, grp.getgrnam(_DEF_GROUP).gr_gid)
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2018-05-24 21:06:09 +00:00
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os.rename(tf.name, filename)
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except OSError as e:
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if tf is not None:
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os.unlink(tf.name)
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raise e
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2022-02-09 18:22:13 +00:00
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def write_file(filename, content, **kwargs):
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"""Atomically write filename.
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open filename in mode 'omode', write content, chmod to 'cmode'.
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"""
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with open_perms(filename, **kwargs) as tf:
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tf.write(content)
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def generate_config(filename, content, **kwargs):
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with open_perms(filename, **kwargs) as tf:
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now = datetime.datetime.utcnow()
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tf.write(f'# Autogenerated by Subiquity: {now} UTC\n')
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tf.write(content)
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