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https://github.com/python/cpython
synced 2024-09-16 05:49:55 +00:00
bpo-43757: Make pathlib use os.path.realpath() to resolve symlinks in a path (GH-25264)
Also adds a new "strict" argument to realpath() to avoid changing the default behaviour of pathlib while sharing the implementation.
This commit is contained in:
parent
859577c249
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baecfbd849
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@ -344,15 +344,24 @@ the :mod:`glob` module.)
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Accepts a :term:`path-like object`.
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.. function:: realpath(path)
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.. function:: realpath(path, *, strict=False)
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Return the canonical path of the specified filename, eliminating any symbolic
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links encountered in the path (if they are supported by the operating
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system).
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If a path doesn't exist or a symlink loop is encountered, and *strict* is
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``True``, :exc:`OSError` is raised. If *strict* is ``False``, the path is
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resolved as far as possible and any remainder is appended without checking
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whether it exists.
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.. note::
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When symbolic link cycles occur, the returned path will be one member of
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the cycle, but no guarantee is made about which member that will be.
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This function emulates the operating system's procedure for making a path
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canonical, which differs slightly between Windows and UNIX with respect
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to how links and subsequent path components interact.
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Operating system APIs make paths canonical as needed, so it's not
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normally necessary to call this function.
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.. versionchanged:: 3.6
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Accepts a :term:`path-like object`.
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@ -360,6 +369,9 @@ the :mod:`glob` module.)
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.. versionchanged:: 3.8
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Symbolic links and junctions are now resolved on Windows.
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.. versionchanged:: 3.10
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The *strict* parameter was added.
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.. function:: relpath(path, start=os.curdir)
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@ -635,7 +635,7 @@ def _getfinalpathname_nonstrict(path):
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tail = join(name, tail) if tail else name
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return tail
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def realpath(path):
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def realpath(path, *, strict=False):
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path = normpath(path)
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if isinstance(path, bytes):
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prefix = b'\\\\?\\'
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@ -660,6 +660,8 @@ def realpath(path):
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path = _getfinalpathname(path)
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initial_winerror = 0
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except OSError as ex:
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if strict:
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raise
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initial_winerror = ex.winerror
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path = _getfinalpathname_nonstrict(path)
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# The path returned by _getfinalpathname will always start with \\?\ -
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125
Lib/pathlib.py
125
Lib/pathlib.py
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@ -14,12 +14,6 @@
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from urllib.parse import quote_from_bytes as urlquote_from_bytes
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if os.name == 'nt':
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from nt import _getfinalpathname
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else:
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_getfinalpathname = None
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__all__ = [
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"PurePath", "PurePosixPath", "PureWindowsPath",
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"Path", "PosixPath", "WindowsPath",
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@ -29,14 +23,17 @@
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# Internals
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#
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_WINERROR_NOT_READY = 21 # drive exists but is not accessible
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_WINERROR_INVALID_NAME = 123 # fix for bpo-35306
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_WINERROR_CANT_RESOLVE_FILENAME = 1921 # broken symlink pointing to itself
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# EBADF - guard against macOS `stat` throwing EBADF
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_IGNORED_ERROS = (ENOENT, ENOTDIR, EBADF, ELOOP)
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_IGNORED_WINERRORS = (
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21, # ERROR_NOT_READY - drive exists but is not accessible
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123, # ERROR_INVALID_NAME - fix for bpo-35306
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1921, # ERROR_CANT_RESOLVE_FILENAME - fix for broken symlink pointing to itself
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)
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_WINERROR_NOT_READY,
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_WINERROR_INVALID_NAME,
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_WINERROR_CANT_RESOLVE_FILENAME)
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def _ignore_error(exception):
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return (getattr(exception, 'errno', None) in _IGNORED_ERROS or
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@ -186,30 +183,6 @@ def casefold_parts(self, parts):
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def compile_pattern(self, pattern):
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return re.compile(fnmatch.translate(pattern), re.IGNORECASE).fullmatch
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def resolve(self, path, strict=False):
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s = str(path)
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if not s:
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return path._accessor.getcwd()
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previous_s = None
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if _getfinalpathname is not None:
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if strict:
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return self._ext_to_normal(_getfinalpathname(s))
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else:
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tail_parts = [] # End of the path after the first one not found
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while True:
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try:
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s = self._ext_to_normal(_getfinalpathname(s))
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except FileNotFoundError:
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previous_s = s
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s, tail = os.path.split(s)
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tail_parts.append(tail)
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if previous_s == s:
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return path
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else:
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return os.path.join(s, *reversed(tail_parts))
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# Means fallback on absolute
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return None
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def _split_extended_path(self, s, ext_prefix=ext_namespace_prefix):
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prefix = ''
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if s.startswith(ext_prefix):
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@ -220,10 +193,6 @@ def _split_extended_path(self, s, ext_prefix=ext_namespace_prefix):
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s = '\\' + s[3:]
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return prefix, s
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def _ext_to_normal(self, s):
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# Turn back an extended path into a normal DOS-like path
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return self._split_extended_path(s)[1]
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def is_reserved(self, parts):
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# NOTE: the rules for reserved names seem somewhat complicated
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# (e.g. r"..\NUL" is reserved but not r"foo\NUL").
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@ -281,54 +250,6 @@ def casefold_parts(self, parts):
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def compile_pattern(self, pattern):
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return re.compile(fnmatch.translate(pattern)).fullmatch
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def resolve(self, path, strict=False):
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sep = self.sep
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accessor = path._accessor
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seen = {}
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def _resolve(path, rest):
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if rest.startswith(sep):
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path = ''
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for name in rest.split(sep):
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if not name or name == '.':
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# current dir
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continue
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if name == '..':
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# parent dir
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path, _, _ = path.rpartition(sep)
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continue
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if path.endswith(sep):
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newpath = path + name
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else:
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newpath = path + sep + name
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if newpath in seen:
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# Already seen this path
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path = seen[newpath]
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if path is not None:
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# use cached value
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continue
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# The symlink is not resolved, so we must have a symlink loop.
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raise RuntimeError("Symlink loop from %r" % newpath)
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# Resolve the symbolic link
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try:
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target = accessor.readlink(newpath)
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except OSError as e:
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if e.errno != EINVAL and strict:
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raise
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# Not a symlink, or non-strict mode. We just leave the path
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# untouched.
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path = newpath
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else:
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seen[newpath] = None # not resolved symlink
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path = _resolve(path, target)
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seen[newpath] = path # resolved symlink
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return path
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# NOTE: according to POSIX, getcwd() cannot contain path components
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# which are symlinks.
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base = '' if path.is_absolute() else accessor.getcwd()
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return _resolve(base, str(path)) or sep
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def is_reserved(self, parts):
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return False
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@ -424,6 +345,8 @@ def group(self, path):
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expanduser = staticmethod(os.path.expanduser)
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realpath = staticmethod(os.path.realpath)
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_normal_accessor = _NormalAccessor()
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@ -1132,15 +1055,27 @@ def resolve(self, strict=False):
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normalizing it (for example turning slashes into backslashes under
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Windows).
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"""
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s = self._flavour.resolve(self, strict=strict)
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if s is None:
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# No symlink resolution => for consistency, raise an error if
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# the path doesn't exist or is forbidden
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self.stat()
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s = str(self.absolute())
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# Now we have no symlinks in the path, it's safe to normalize it.
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normed = self._flavour.pathmod.normpath(s)
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return self._from_parts((normed,))
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def check_eloop(e):
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winerror = getattr(e, 'winerror', 0)
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if e.errno == ELOOP or winerror == _WINERROR_CANT_RESOLVE_FILENAME:
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raise RuntimeError("Symlink loop from %r" % e.filename)
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try:
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s = self._accessor.realpath(self, strict=strict)
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except OSError as e:
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check_eloop(e)
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raise
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p = self._from_parts((s,))
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# In non-strict mode, realpath() doesn't raise on symlink loops.
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# Ensure we get an exception by calling stat()
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if not strict:
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try:
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p.stat()
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except OSError as e:
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check_eloop(e)
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return p
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def stat(self, *, follow_symlinks=True):
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"""
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@ -387,16 +387,16 @@ def abspath(path):
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# Return a canonical path (i.e. the absolute location of a file on the
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# filesystem).
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def realpath(filename):
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def realpath(filename, *, strict=False):
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"""Return the canonical path of the specified filename, eliminating any
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symbolic links encountered in the path."""
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filename = os.fspath(filename)
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path, ok = _joinrealpath(filename[:0], filename, {})
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path, ok = _joinrealpath(filename[:0], filename, strict, {})
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return abspath(path)
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# Join two paths, normalizing and eliminating any symbolic links
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# encountered in the second path.
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def _joinrealpath(path, rest, seen):
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def _joinrealpath(path, rest, strict, seen):
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if isinstance(path, bytes):
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sep = b'/'
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curdir = b'.'
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path = pardir
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continue
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newpath = join(path, name)
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if not islink(newpath):
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try:
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st = os.lstat(newpath)
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except OSError:
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if strict:
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raise
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is_link = False
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else:
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is_link = stat.S_ISLNK(st.st_mode)
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if not is_link:
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path = newpath
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continue
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# Resolve the symbolic link
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# use cached value
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continue
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# The symlink is not resolved, so we must have a symlink loop.
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# Return already resolved part + rest of the path unchanged.
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return join(newpath, rest), False
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if strict:
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# Raise OSError(errno.ELOOP)
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os.stat(newpath)
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else:
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# Return already resolved part + rest of the path unchanged.
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return join(newpath, rest), False
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seen[newpath] = None # not resolved symlink
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path, ok = _joinrealpath(path, os.readlink(newpath), seen)
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path, ok = _joinrealpath(path, os.readlink(newpath), strict, seen)
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if not ok:
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return join(path, rest), False
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seen[newpath] = path # resolved symlink
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@ -269,6 +269,17 @@ def test_realpath_basic(self):
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self.assertPathEqual(ntpath.realpath(os.fsencode(ABSTFN + "1")),
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os.fsencode(ABSTFN))
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@os_helper.skip_unless_symlink
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@unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname')
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def test_realpath_strict(self):
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# Bug #43757: raise FileNotFoundError in strict mode if we encounter
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# a path that does not exist.
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ABSTFN = ntpath.abspath(os_helper.TESTFN)
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os.symlink(ABSTFN + "1", ABSTFN)
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self.addCleanup(os_helper.unlink, ABSTFN)
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self.assertRaises(FileNotFoundError, ntpath.realpath, ABSTFN, strict=True)
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self.assertRaises(FileNotFoundError, ntpath.realpath, ABSTFN + "2", strict=True)
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@os_helper.skip_unless_symlink
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@unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname')
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def test_realpath_relative(self):
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@ -340,8 +351,9 @@ def test_realpath_broken_symlinks(self):
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@os_helper.skip_unless_symlink
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@unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname')
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def test_realpath_symlink_loops(self):
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# Symlink loops are non-deterministic as to which path is returned, but
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# it will always be the fully resolved path of one member of the cycle
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# Symlink loops in non-strict mode are non-deterministic as to which
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# path is returned, but it will always be the fully resolved path of
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# one member of the cycle
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ABSTFN = ntpath.abspath(os_helper.TESTFN)
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self.addCleanup(os_helper.unlink, ABSTFN)
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self.addCleanup(os_helper.unlink, ABSTFN + "1")
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# Test using relative path as well.
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self.assertPathEqual(ntpath.realpath(ntpath.basename(ABSTFN)), ABSTFN)
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@os_helper.skip_unless_symlink
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@unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname')
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def test_realpath_symlink_loops_strict(self):
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# Symlink loops raise OSError in strict mode
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ABSTFN = ntpath.abspath(os_helper.TESTFN)
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self.addCleanup(os_helper.unlink, ABSTFN)
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self.addCleanup(os_helper.unlink, ABSTFN + "1")
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self.addCleanup(os_helper.unlink, ABSTFN + "2")
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self.addCleanup(os_helper.unlink, ABSTFN + "y")
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self.addCleanup(os_helper.unlink, ABSTFN + "c")
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self.addCleanup(os_helper.unlink, ABSTFN + "a")
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os.symlink(ABSTFN, ABSTFN)
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self.assertRaises(OSError, ntpath.realpath, ABSTFN, strict=True)
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os.symlink(ABSTFN + "1", ABSTFN + "2")
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os.symlink(ABSTFN + "2", ABSTFN + "1")
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self.assertRaises(OSError, ntpath.realpath, ABSTFN + "1", strict=True)
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self.assertRaises(OSError, ntpath.realpath, ABSTFN + "2", strict=True)
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self.assertRaises(OSError, ntpath.realpath, ABSTFN + "1\\x", strict=True)
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# Windows eliminates '..' components before resolving links, so the
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# following call is not expected to raise.
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self.assertPathEqual(ntpath.realpath(ABSTFN + "1\\..", strict=True),
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ntpath.dirname(ABSTFN))
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self.assertRaises(OSError, ntpath.realpath, ABSTFN + "1\\..\\x", strict=True)
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os.symlink(ABSTFN + "x", ABSTFN + "y")
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self.assertRaises(OSError, ntpath.realpath, ABSTFN + "1\\..\\"
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+ ntpath.basename(ABSTFN) + "y",
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strict=True)
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self.assertRaises(OSError, ntpath.realpath,
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ABSTFN + "1\\..\\" + ntpath.basename(ABSTFN) + "1",
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strict=True)
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os.symlink(ntpath.basename(ABSTFN) + "a\\b", ABSTFN + "a")
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self.assertRaises(OSError, ntpath.realpath, ABSTFN + "a", strict=True)
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os.symlink("..\\" + ntpath.basename(ntpath.dirname(ABSTFN))
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+ "\\" + ntpath.basename(ABSTFN) + "c", ABSTFN + "c")
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self.assertRaises(OSError, ntpath.realpath, ABSTFN + "c", strict=True)
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# Test using relative path as well.
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self.assertRaises(OSError, ntpath.realpath, ntpath.basename(ABSTFN),
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strict=True)
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@os_helper.skip_unless_symlink
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@unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname')
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def test_realpath_symlink_prefix(self):
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@ -355,6 +355,19 @@ def test_realpath_basic(self):
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finally:
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os_helper.unlink(ABSTFN)
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@unittest.skipUnless(hasattr(os, "symlink"),
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"Missing symlink implementation")
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@skip_if_ABSTFN_contains_backslash
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def test_realpath_strict(self):
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# Bug #43757: raise FileNotFoundError in strict mode if we encounter
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# a path that does not exist.
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try:
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os.symlink(ABSTFN+"1", ABSTFN)
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self.assertRaises(FileNotFoundError, realpath, ABSTFN, strict=True)
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self.assertRaises(FileNotFoundError, realpath, ABSTFN + "2", strict=True)
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finally:
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os_helper.unlink(ABSTFN)
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@unittest.skipUnless(hasattr(os, "symlink"),
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"Missing symlink implementation")
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@skip_if_ABSTFN_contains_backslash
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@ -370,7 +383,7 @@ def test_realpath_relative(self):
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@skip_if_ABSTFN_contains_backslash
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def test_realpath_symlink_loops(self):
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# Bug #930024, return the path unchanged if we get into an infinite
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# symlink loop.
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# symlink loop in non-strict mode (default).
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try:
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os.symlink(ABSTFN, ABSTFN)
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self.assertEqual(realpath(ABSTFN), ABSTFN)
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@ -407,6 +420,48 @@ def test_realpath_symlink_loops(self):
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os_helper.unlink(ABSTFN+"c")
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os_helper.unlink(ABSTFN+"a")
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@unittest.skipUnless(hasattr(os, "symlink"),
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"Missing symlink implementation")
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@skip_if_ABSTFN_contains_backslash
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def test_realpath_symlink_loops_strict(self):
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# Bug #43757, raise OSError if we get into an infinite symlink loop in
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# strict mode.
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try:
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os.symlink(ABSTFN, ABSTFN)
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self.assertRaises(OSError, realpath, ABSTFN, strict=True)
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os.symlink(ABSTFN+"1", ABSTFN+"2")
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os.symlink(ABSTFN+"2", ABSTFN+"1")
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self.assertRaises(OSError, realpath, ABSTFN+"1", strict=True)
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self.assertRaises(OSError, realpath, ABSTFN+"2", strict=True)
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|
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self.assertRaises(OSError, realpath, ABSTFN+"1/x", strict=True)
|
||||
self.assertRaises(OSError, realpath, ABSTFN+"1/..", strict=True)
|
||||
self.assertRaises(OSError, realpath, ABSTFN+"1/../x", strict=True)
|
||||
os.symlink(ABSTFN+"x", ABSTFN+"y")
|
||||
self.assertRaises(OSError, realpath,
|
||||
ABSTFN+"1/../" + basename(ABSTFN) + "y", strict=True)
|
||||
self.assertRaises(OSError, realpath,
|
||||
ABSTFN+"1/../" + basename(ABSTFN) + "1", strict=True)
|
||||
|
||||
os.symlink(basename(ABSTFN) + "a/b", ABSTFN+"a")
|
||||
self.assertRaises(OSError, realpath, ABSTFN+"a", strict=True)
|
||||
|
||||
os.symlink("../" + basename(dirname(ABSTFN)) + "/" +
|
||||
basename(ABSTFN) + "c", ABSTFN+"c")
|
||||
self.assertRaises(OSError, realpath, ABSTFN+"c", strict=True)
|
||||
|
||||
# Test using relative path as well.
|
||||
with os_helper.change_cwd(dirname(ABSTFN)):
|
||||
self.assertRaises(OSError, realpath, basename(ABSTFN), strict=True)
|
||||
finally:
|
||||
os_helper.unlink(ABSTFN)
|
||||
os_helper.unlink(ABSTFN+"1")
|
||||
os_helper.unlink(ABSTFN+"2")
|
||||
os_helper.unlink(ABSTFN+"y")
|
||||
os_helper.unlink(ABSTFN+"c")
|
||||
os_helper.unlink(ABSTFN+"a")
|
||||
|
||||
@unittest.skipUnless(hasattr(os, "symlink"),
|
||||
"Missing symlink implementation")
|
||||
@skip_if_ABSTFN_contains_backslash
|
||||
|
|
|
@ -0,0 +1,3 @@
|
|||
:func:`os.path.realpath` now accepts a *strict* keyword-only argument.
|
||||
When set to ``True``, :exc:`OSError` is raised if a path doesn't exist
|
||||
or a symlink loop is encountered.
|
Loading…
Reference in a new issue