Current File : //usr/lib/python3.12/test/support/os_helper.py
import collections.abc
import contextlib
import errno
import os
import re
import stat
import string
import sys
import time
import unittest
import warnings
from test import support
# Filename used for testing
TESTFN_ASCII = '@test'
# Disambiguate TESTFN for parallel testing, while letting it remain a valid
# module name.
TESTFN_ASCII = "{}_{}_tmp".format(TESTFN_ASCII, os.getpid())
# TESTFN_UNICODE is a non-ascii filename
TESTFN_UNICODE = TESTFN_ASCII + "-\xe0\xf2\u0258\u0141\u011f"
if sys.platform == 'darwin':
# In Mac OS X's VFS API file names are, by definition, canonically
# decomposed Unicode, encoded using UTF-8. See QA1173:
# http://developer.apple.com/mac/library/qa/qa2001/qa1173.html
import unicodedata
TESTFN_UNICODE = unicodedata.normalize('NFD', TESTFN_UNICODE)
# TESTFN_UNENCODABLE is a filename (str type) that should *not* be able to be
# encoded by the filesystem encoding (in strict mode). It can be None if we
# cannot generate such filename.
TESTFN_UNENCODABLE = None
if os.name == 'nt':
# skip win32s (0) or Windows 9x/ME (1)
if sys.getwindowsversion().platform >= 2:
# Different kinds of characters from various languages to minimize the
# probability that the whole name is encodable to MBCS (issue #9819)
TESTFN_UNENCODABLE = TESTFN_ASCII + "-\u5171\u0141\u2661\u0363\uDC80"
try:
TESTFN_UNENCODABLE.encode(sys.getfilesystemencoding())
except UnicodeEncodeError:
pass
else:
print('WARNING: The filename %r CAN be encoded by the filesystem '
'encoding (%s). Unicode filename tests may not be effective'
% (TESTFN_UNENCODABLE, sys.getfilesystemencoding()))
TESTFN_UNENCODABLE = None
# macOS and Emscripten deny unencodable filenames (invalid utf-8)
elif sys.platform not in {'darwin', 'emscripten', 'wasi'}:
try:
# ascii and utf-8 cannot encode the byte 0xff
b'\xff'.decode(sys.getfilesystemencoding())
except UnicodeDecodeError:
# 0xff will be encoded using the surrogate character u+DCFF
TESTFN_UNENCODABLE = TESTFN_ASCII \
+ b'-\xff'.decode(sys.getfilesystemencoding(), 'surrogateescape')
else:
# File system encoding (eg. ISO-8859-* encodings) can encode
# the byte 0xff. Skip some unicode filename tests.
pass
# FS_NONASCII: non-ASCII character encodable by os.fsencode(),
# or an empty string if there is no such character.
FS_NONASCII = ''
for character in (
# First try printable and common characters to have a readable filename.
# For each character, the encoding list are just example of encodings able
# to encode the character (the list is not exhaustive).
# U+00E6 (Latin Small Letter Ae): cp1252, iso-8859-1
'\u00E6',
# U+0130 (Latin Capital Letter I With Dot Above): cp1254, iso8859_3
'\u0130',
# U+0141 (Latin Capital Letter L With Stroke): cp1250, cp1257
'\u0141',
# U+03C6 (Greek Small Letter Phi): cp1253
'\u03C6',
# U+041A (Cyrillic Capital Letter Ka): cp1251
'\u041A',
# U+05D0 (Hebrew Letter Alef): Encodable to cp424
'\u05D0',
# U+060C (Arabic Comma): cp864, cp1006, iso8859_6, mac_arabic
'\u060C',
# U+062A (Arabic Letter Teh): cp720
'\u062A',
# U+0E01 (Thai Character Ko Kai): cp874
'\u0E01',
# Then try more "special" characters. "special" because they may be
# interpreted or displayed differently depending on the exact locale
# encoding and the font.
# U+00A0 (No-Break Space)
'\u00A0',
# U+20AC (Euro Sign)
'\u20AC',
):
try:
# If Python is set up to use the legacy 'mbcs' in Windows,
# 'replace' error mode is used, and encode() returns b'?'
# for characters missing in the ANSI codepage
if os.fsdecode(os.fsencode(character)) != character:
raise UnicodeError
except UnicodeError:
pass
else:
FS_NONASCII = character
break
# Save the initial cwd
SAVEDCWD = os.getcwd()
# TESTFN_UNDECODABLE is a filename (bytes type) that should *not* be able to be
# decoded from the filesystem encoding (in strict mode). It can be None if we
# cannot generate such filename (ex: the latin1 encoding can decode any byte
# sequence). On UNIX, TESTFN_UNDECODABLE can be decoded by os.fsdecode() thanks
# to the surrogateescape error handler (PEP 383), but not from the filesystem
# encoding in strict mode.
TESTFN_UNDECODABLE = None
for name in (
# b'\xff' is not decodable by os.fsdecode() with code page 932. Windows
# accepts it to create a file or a directory, or don't accept to enter to
# such directory (when the bytes name is used). So test b'\xe7' first:
# it is not decodable from cp932.
b'\xe7w\xf0',
# undecodable from ASCII, UTF-8
b'\xff',
# undecodable from iso8859-3, iso8859-6, iso8859-7, cp424, iso8859-8, cp856
# and cp857
b'\xae\xd5'
# undecodable from UTF-8 (UNIX and Mac OS X)
b'\xed\xb2\x80', b'\xed\xb4\x80',
# undecodable from shift_jis, cp869, cp874, cp932, cp1250, cp1251, cp1252,
# cp1253, cp1254, cp1255, cp1257, cp1258
b'\x81\x98',
):
try:
name.decode(sys.getfilesystemencoding())
except UnicodeDecodeError:
try:
name.decode(sys.getfilesystemencoding(),
sys.getfilesystemencodeerrors())
except UnicodeDecodeError:
continue
TESTFN_UNDECODABLE = os.fsencode(TESTFN_ASCII) + name
break
if FS_NONASCII:
TESTFN_NONASCII = TESTFN_ASCII + FS_NONASCII
else:
TESTFN_NONASCII = None
TESTFN = TESTFN_NONASCII or TESTFN_ASCII
def make_bad_fd():
"""
Create an invalid file descriptor by opening and closing a file and return
its fd.
"""
file = open(TESTFN, "wb")
try:
return file.fileno()
finally:
file.close()
unlink(TESTFN)
_can_symlink = None
def can_symlink():
global _can_symlink
if _can_symlink is not None:
return _can_symlink
# WASI / wasmtime prevents symlinks with absolute paths, see man
# openat2(2) RESOLVE_BENEATH. Almost all symlink tests use absolute
# paths. Skip symlink tests on WASI for now.
src = os.path.abspath(TESTFN)
symlink_path = src + "can_symlink"
try:
os.symlink(src, symlink_path)
can = True
except (OSError, NotImplementedError, AttributeError):
can = False
else:
os.remove(symlink_path)
_can_symlink = can
return can
def skip_unless_symlink(test):
"""Skip decorator for tests that require functional symlink"""
ok = can_symlink()
msg = "Requires functional symlink implementation"
return test if ok else unittest.skip(msg)(test)
_can_xattr = None
def can_xattr():
import tempfile
global _can_xattr
if _can_xattr is not None:
return _can_xattr
if not hasattr(os, "setxattr"):
can = False
else:
import platform
tmp_dir = tempfile.mkdtemp()
tmp_fp, tmp_name = tempfile.mkstemp(dir=tmp_dir)
try:
with open(TESTFN, "wb") as fp:
try:
# TESTFN & tempfile may use different file systems with
# different capabilities
os.setxattr(tmp_fp, b"user.test", b"")
os.setxattr(tmp_name, b"trusted.foo", b"42")
os.setxattr(fp.fileno(), b"user.test", b"")
# Kernels < 2.6.39 don't respect setxattr flags.
kernel_version = platform.release()
m = re.match(r"2.6.(\d{1,2})", kernel_version)
can = m is None or int(m.group(1)) >= 39
except OSError:
can = False
finally:
unlink(TESTFN)
unlink(tmp_name)
rmdir(tmp_dir)
_can_xattr = can
return can
def skip_unless_xattr(test):
"""Skip decorator for tests that require functional extended attributes"""
ok = can_xattr()
msg = "no non-broken extended attribute support"
return test if ok else unittest.skip(msg)(test)
_can_chmod = None
def can_chmod():
global _can_chmod
if _can_chmod is not None:
return _can_chmod
if not hasattr(os, "chmod"):
_can_chmod = False
return _can_chmod
try:
with open(TESTFN, "wb") as f:
try:
os.chmod(TESTFN, 0o555)
mode1 = os.stat(TESTFN).st_mode
os.chmod(TESTFN, 0o777)
mode2 = os.stat(TESTFN).st_mode
except OSError as e:
can = False
else:
can = stat.S_IMODE(mode1) != stat.S_IMODE(mode2)
finally:
unlink(TESTFN)
_can_chmod = can
return can
def skip_unless_working_chmod(test):
"""Skip tests that require working os.chmod()
WASI SDK 15.0 cannot change file mode bits.
"""
ok = can_chmod()
msg = "requires working os.chmod()"
return test if ok else unittest.skip(msg)(test)
# Check whether the current effective user has the capability to override
# DAC (discretionary access control). Typically user root is able to
# bypass file read, write, and execute permission checks. The capability
# is independent of the effective user. See capabilities(7).
_can_dac_override = None
def can_dac_override():
global _can_dac_override
if not can_chmod():
_can_dac_override = False
if _can_dac_override is not None:
return _can_dac_override
try:
with open(TESTFN, "wb") as f:
os.chmod(TESTFN, 0o400)
try:
with open(TESTFN, "wb"):
pass
except OSError:
_can_dac_override = False
else:
_can_dac_override = True
finally:
try:
os.chmod(TESTFN, 0o700)
except OSError:
pass
unlink(TESTFN)
return _can_dac_override
def skip_if_dac_override(test):
ok = not can_dac_override()
msg = "incompatible with CAP_DAC_OVERRIDE"
return test if ok else unittest.skip(msg)(test)
def skip_unless_dac_override(test):
ok = can_dac_override()
msg = "requires CAP_DAC_OVERRIDE"
return test if ok else unittest.skip(msg)(test)
def unlink(filename):
try:
_unlink(filename)
except (FileNotFoundError, NotADirectoryError):
pass
if sys.platform.startswith("win"):
def _waitfor(func, pathname, waitall=False):
# Perform the operation
func(pathname)
# Now setup the wait loop
if waitall:
dirname = pathname
else:
dirname, name = os.path.split(pathname)
dirname = dirname or '.'
# Check for `pathname` to be removed from the filesystem.
# The exponential backoff of the timeout amounts to a total
# of ~1 second after which the deletion is probably an error
# anyway.
# Testing on an i7@4.3GHz shows that usually only 1 iteration is
# required when contention occurs.
timeout = 0.001
while timeout < 1.0:
# Note we are only testing for the existence of the file(s) in
# the contents of the directory regardless of any security or
# access rights. If we have made it this far, we have sufficient
# permissions to do that much using Python's equivalent of the
# Windows API FindFirstFile.
# Other Windows APIs can fail or give incorrect results when
# dealing with files that are pending deletion.
L = os.listdir(dirname)
if not (L if waitall else name in L):
return
# Increase the timeout and try again
time.sleep(timeout)
timeout *= 2
warnings.warn('tests may fail, delete still pending for ' + pathname,
RuntimeWarning, stacklevel=4)
def _unlink(filename):
_waitfor(os.unlink, filename)
def _rmdir(dirname):
_waitfor(os.rmdir, dirname)
def _rmtree(path):
from test.support import _force_run
def _rmtree_inner(path):
for name in _force_run(path, os.listdir, path):
fullname = os.path.join(path, name)
try:
mode = os.lstat(fullname).st_mode
except OSError as exc:
print("support.rmtree(): os.lstat(%r) failed with %s"
% (fullname, exc),
file=sys.__stderr__)
mode = 0
if stat.S_ISDIR(mode):
_waitfor(_rmtree_inner, fullname, waitall=True)
_force_run(fullname, os.rmdir, fullname)
else:
_force_run(fullname, os.unlink, fullname)
_waitfor(_rmtree_inner, path, waitall=True)
_waitfor(lambda p: _force_run(p, os.rmdir, p), path)
def _longpath(path):
try:
import ctypes
except ImportError:
# No ctypes means we can't expands paths.
pass
else:
buffer = ctypes.create_unicode_buffer(len(path) * 2)
length = ctypes.windll.kernel32.GetLongPathNameW(path, buffer,
len(buffer))
if length:
return buffer[:length]
return path
else:
_unlink = os.unlink
_rmdir = os.rmdir
def _rmtree(path):
import shutil
try:
shutil.rmtree(path)
return
except OSError:
pass
def _rmtree_inner(path):
from test.support import _force_run
for name in _force_run(path, os.listdir, path):
fullname = os.path.join(path, name)
try:
mode = os.lstat(fullname).st_mode
except OSError:
mode = 0
if stat.S_ISDIR(mode):
_rmtree_inner(fullname)
_force_run(path, os.rmdir, fullname)
else:
_force_run(path, os.unlink, fullname)
_rmtree_inner(path)
os.rmdir(path)
def _longpath(path):
return path
def rmdir(dirname):
try:
_rmdir(dirname)
except FileNotFoundError:
pass
def rmtree(path):
try:
_rmtree(path)
except FileNotFoundError:
pass
@contextlib.contextmanager
def temp_dir(path=None, quiet=False):
"""Return a context manager that creates a temporary directory.
Arguments:
path: the directory to create temporarily. If omitted or None,
defaults to creating a temporary directory using tempfile.mkdtemp.
quiet: if False (the default), the context manager raises an exception
on error. Otherwise, if the path is specified and cannot be
created, only a warning is issued.
"""
import tempfile
dir_created = False
if path is None:
path = tempfile.mkdtemp()
dir_created = True
path = os.path.realpath(path)
else:
try:
os.mkdir(path)
dir_created = True
except OSError as exc:
if not quiet:
raise
warnings.warn(f'tests may fail, unable to create '
f'temporary directory {path!r}: {exc}',
RuntimeWarning, stacklevel=3)
if dir_created:
pid = os.getpid()
try:
yield path
finally:
# In case the process forks, let only the parent remove the
# directory. The child has a different process id. (bpo-30028)
if dir_created and pid == os.getpid():
rmtree(path)
@contextlib.contextmanager
def change_cwd(path, quiet=False):
"""Return a context manager that changes the current working directory.
Arguments:
path: the directory to use as the temporary current working directory.
quiet: if False (the default), the context manager raises an exception
on error. Otherwise, it issues only a warning and keeps the current
working directory the same.
"""
saved_dir = os.getcwd()
try:
os.chdir(os.path.realpath(path))
except OSError as exc:
if not quiet:
raise
warnings.warn(f'tests may fail, unable to change the current working '
f'directory to {path!r}: {exc}',
RuntimeWarning, stacklevel=3)
try:
yield os.getcwd()
finally:
os.chdir(saved_dir)
@contextlib.contextmanager
def temp_cwd(name='tempcwd', quiet=False):
"""
Context manager that temporarily creates and changes the CWD.
The function temporarily changes the current working directory
after creating a temporary directory in the current directory with
name *name*. If *name* is None, the temporary directory is
created using tempfile.mkdtemp.
If *quiet* is False (default) and it is not possible to
create or change the CWD, an error is raised. If *quiet* is True,
only a warning is raised and the original CWD is used.
"""
with temp_dir(path=name, quiet=quiet) as temp_path:
with change_cwd(temp_path, quiet=quiet) as cwd_dir:
yield cwd_dir
def create_empty_file(filename):
"""Create an empty file. If the file already exists, truncate it."""
fd = os.open(filename, os.O_WRONLY | os.O_CREAT | os.O_TRUNC)
os.close(fd)
@contextlib.contextmanager
def open_dir_fd(path):
"""Open a file descriptor to a directory."""
assert os.path.isdir(path)
flags = os.O_RDONLY
if hasattr(os, "O_DIRECTORY"):
flags |= os.O_DIRECTORY
dir_fd = os.open(path, flags)
try:
yield dir_fd
finally:
os.close(dir_fd)
def fs_is_case_insensitive(directory):
"""Detects if the file system for the specified directory
is case-insensitive."""
import tempfile
with tempfile.NamedTemporaryFile(dir=directory) as base:
base_path = base.name
case_path = base_path.upper()
if case_path == base_path:
case_path = base_path.lower()
try:
return os.path.samefile(base_path, case_path)
except FileNotFoundError:
return False
class FakePath:
"""Simple implementation of the path protocol.
"""
def __init__(self, path):
self.path = path
def __repr__(self):
return f'<FakePath {self.path!r}>'
def __fspath__(self):
if (isinstance(self.path, BaseException) or
isinstance(self.path, type) and
issubclass(self.path, BaseException)):
raise self.path
else:
return self.path
def fd_count():
"""Count the number of open file descriptors.
"""
if sys.platform.startswith(('linux', 'freebsd', 'emscripten')):
fd_path = "/proc/self/fd"
elif sys.platform == "darwin":
fd_path = "/dev/fd"
else:
fd_path = None
if fd_path is not None:
try:
names = os.listdir(fd_path)
# Subtract one because listdir() internally opens a file
# descriptor to list the content of the directory.
return len(names) - 1
except FileNotFoundError:
pass
MAXFD = 256
if hasattr(os, 'sysconf'):
try:
MAXFD = os.sysconf("SC_OPEN_MAX")
except OSError:
pass
old_modes = None
if sys.platform == 'win32':
# bpo-25306, bpo-31009: Call CrtSetReportMode() to not kill the process
# on invalid file descriptor if Python is compiled in debug mode
try:
import msvcrt
msvcrt.CrtSetReportMode
except (AttributeError, ImportError):
# no msvcrt or a release build
pass
else:
old_modes = {}
for report_type in (msvcrt.CRT_WARN,
msvcrt.CRT_ERROR,
msvcrt.CRT_ASSERT):
old_modes[report_type] = msvcrt.CrtSetReportMode(report_type,
0)
try:
count = 0
for fd in range(MAXFD):
try:
# Prefer dup() over fstat(). fstat() can require input/output
# whereas dup() doesn't.
fd2 = os.dup(fd)
except OSError as e:
if e.errno != errno.EBADF:
raise
else:
os.close(fd2)
count += 1
finally:
if old_modes is not None:
for report_type in (msvcrt.CRT_WARN,
msvcrt.CRT_ERROR,
msvcrt.CRT_ASSERT):
msvcrt.CrtSetReportMode(report_type, old_modes[report_type])
return count
if hasattr(os, "umask"):
@contextlib.contextmanager
def temp_umask(umask):
"""Context manager that temporarily sets the process umask."""
oldmask = os.umask(umask)
try:
yield
finally:
os.umask(oldmask)
else:
@contextlib.contextmanager
def temp_umask(umask):
"""no-op on platforms without umask()"""
yield
class EnvironmentVarGuard(collections.abc.MutableMapping):
"""Class to help protect the environment variable properly. Can be used as
a context manager."""
def __init__(self):
self._environ = os.environ
self._changed = {}
def __getitem__(self, envvar):
return self._environ[envvar]
def __setitem__(self, envvar, value):
# Remember the initial value on the first access
if envvar not in self._changed:
self._changed[envvar] = self._environ.get(envvar)
self._environ[envvar] = value
def __delitem__(self, envvar):
# Remember the initial value on the first access
if envvar not in self._changed:
self._changed[envvar] = self._environ.get(envvar)
if envvar in self._environ:
del self._environ[envvar]
def keys(self):
return self._environ.keys()
def __iter__(self):
return iter(self._environ)
def __len__(self):
return len(self._environ)
def set(self, envvar, value):
self[envvar] = value
def unset(self, envvar):
del self[envvar]
def copy(self):
# We do what os.environ.copy() does.
return dict(self)
def __enter__(self):
return self
def __exit__(self, *ignore_exc):
for (k, v) in self._changed.items():
if v is None:
if k in self._environ:
del self._environ[k]
else:
self._environ[k] = v
os.environ = self._environ
try:
if support.MS_WINDOWS:
import ctypes
kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)
ERROR_FILE_NOT_FOUND = 2
DDD_REMOVE_DEFINITION = 2
DDD_EXACT_MATCH_ON_REMOVE = 4
DDD_NO_BROADCAST_SYSTEM = 8
else:
raise AttributeError
except (ImportError, AttributeError):
def subst_drive(path):
raise unittest.SkipTest('ctypes or kernel32 is not available')
else:
@contextlib.contextmanager
def subst_drive(path):
"""Temporarily yield a substitute drive for a given path."""
for c in reversed(string.ascii_uppercase):
drive = f'{c}:'
if (not kernel32.QueryDosDeviceW(drive, None, 0) and
ctypes.get_last_error() == ERROR_FILE_NOT_FOUND):
break
else:
raise unittest.SkipTest('no available logical drive')
if not kernel32.DefineDosDeviceW(
DDD_NO_BROADCAST_SYSTEM, drive, path):
raise ctypes.WinError(ctypes.get_last_error())
try:
yield drive
finally:
if not kernel32.DefineDosDeviceW(
DDD_REMOVE_DEFINITION | DDD_EXACT_MATCH_ON_REMOVE,
drive, path):
raise ctypes.WinError(ctypes.get_last_error())
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