457ea43e95
`mypy` only understands `sys.platform == "win32"`, not indirect assignments of that value to things like `is_windows`. If we don't use the accepted platform checks, `mypy` registers many Windows-only symbols as not present on Linux, when it should skip the checks for platform-specific code.
87 lines
2.8 KiB
Python
87 lines
2.8 KiB
Python
# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
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# Spack Project Developers. See the top-level COPYRIGHT file for details.
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#
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# SPDX-License-Identifier: (Apache-2.0 OR MIT)
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"""Wrapper for ``llnl.util.lock`` allows locking to be enabled/disabled."""
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import os
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import stat
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import sys
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import llnl.util.lock
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# import some llnl.util.lock names as though they're part of spack.util.lock
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from llnl.util.lock import LockError # noqa: F401
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from llnl.util.lock import LockTimeoutError # noqa: F401
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from llnl.util.lock import LockUpgradeError # noqa: F401
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from llnl.util.lock import ReadTransaction # noqa: F401
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from llnl.util.lock import WriteTransaction # noqa: F401
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import spack.config
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import spack.error
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import spack.paths
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class Lock(llnl.util.lock.Lock):
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"""Lock that can be disabled.
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This overrides the ``_lock()`` and ``_unlock()`` methods from
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``llnl.util.lock`` so that all the lock API calls will succeed, but
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the actual locking mechanism can be disabled via ``_enable_locks``.
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"""
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def __init__(self, *args, **kwargs):
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super(Lock, self).__init__(*args, **kwargs)
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self._enable = spack.config.get("config:locks", sys.platform != "win32")
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def _lock(self, op, timeout=0):
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if self._enable:
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return super(Lock, self)._lock(op, timeout)
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else:
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return 0, 0
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def _unlock(self):
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"""Unlock call that always succeeds."""
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if self._enable:
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super(Lock, self)._unlock()
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def _debug(self, *args):
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if self._enable:
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super(Lock, self)._debug(*args)
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def cleanup(self, *args):
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if self._enable:
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super(Lock, self).cleanup(*args)
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def check_lock_safety(path):
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"""Do some extra checks to ensure disabling locks is safe.
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This will raise an error if ``path`` can is group- or world-writable
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AND the current user can write to the directory (i.e., if this user
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AND others could write to the path).
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This is intended to run on the Spack prefix, but can be run on any
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path for testing.
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"""
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if os.access(path, os.W_OK):
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stat_result = os.stat(path)
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uid, gid = stat_result.st_uid, stat_result.st_gid
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mode = stat_result[stat.ST_MODE]
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writable = None
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if (mode & stat.S_IWGRP) and (uid != gid):
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# spack is group-writeable and the group is not the owner
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writable = "group"
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elif mode & stat.S_IWOTH:
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# spack is world-writeable
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writable = "world"
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if writable:
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msg = "Refusing to disable locks: spack is {0}-writable.".format(writable)
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long_msg = (
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"Running a shared spack without locks is unsafe. You must "
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"restrict permissions on {0} or enable locks."
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).format(path)
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raise spack.error.SpackError(msg, long_msg)
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