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gh-83499: Fix closing file descriptors in tempfile (GH-93874)
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@serhiy-storchaka
serhiy-storchaka authored Jun 26, 2022
1 parent 5369858 commit d4792ce
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Showing 3 changed files with 106 additions and 64 deletions.
79 changes: 51 additions & 28 deletions Lib/tempfile.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -203,8 +203,7 @@ def _get_default_tempdir():
fd = _os.open(filename, _bin_openflags, 0o600)
try:
try:
with _io.open(fd, 'wb', closefd=False) as fp:
fp.write(b'blat')
_os.write(fd, b'blat')
finally:
_os.close(fd)
finally:
Expand Down Expand Up @@ -244,6 +243,7 @@ def _get_candidate_names():
def _mkstemp_inner(dir, pre, suf, flags, output_type):
"""Code common to mkstemp, TemporaryFile, and NamedTemporaryFile."""

dir = _os.path.abspath(dir)
names = _get_candidate_names()
if output_type is bytes:
names = map(_os.fsencode, names)
Expand All @@ -264,7 +264,7 @@ def _mkstemp_inner(dir, pre, suf, flags, output_type):
continue
else:
raise
return (fd, _os.path.abspath(file))
return fd, file

raise FileExistsError(_errno.EEXIST,
"No usable temporary file name found")
Expand Down Expand Up @@ -554,15 +554,26 @@ def NamedTemporaryFile(mode='w+b', buffering=-1, encoding=None,
if "b" not in mode:
encoding = _io.text_encoding(encoding)

(fd, name) = _mkstemp_inner(dir, prefix, suffix, flags, output_type)
name = None
def opener(*args):
nonlocal name
fd, name = _mkstemp_inner(dir, prefix, suffix, flags, output_type)
return fd
try:
file = _io.open(fd, mode, buffering=buffering,
newline=newline, encoding=encoding, errors=errors)

return _TemporaryFileWrapper(file, name, delete)
except BaseException:
_os.unlink(name)
_os.close(fd)
file = _io.open(dir, mode, buffering=buffering,
newline=newline, encoding=encoding, errors=errors,
opener=opener)
try:
raw = getattr(file, 'buffer', file)
raw = getattr(raw, 'raw', raw)
raw.name = name
return _TemporaryFileWrapper(file, name, delete)
except:
file.close()
raise
except:
if name is not None and not (_os.name == 'nt' and delete):
_os.unlink(name)
raise

if _os.name != 'posix' or _sys.platform == 'cygwin':
Expand Down Expand Up @@ -601,9 +612,20 @@ def TemporaryFile(mode='w+b', buffering=-1, encoding=None,

flags = _bin_openflags
if _O_TMPFILE_WORKS:
try:
fd = None
def opener(*args):
nonlocal fd
flags2 = (flags | _os.O_TMPFILE) & ~_os.O_CREAT
fd = _os.open(dir, flags2, 0o600)
return fd
try:
file = _io.open(dir, mode, buffering=buffering,
newline=newline, encoding=encoding,
errors=errors, opener=opener)
raw = getattr(file, 'buffer', file)
raw = getattr(raw, 'raw', raw)
raw.name = fd
return file
except IsADirectoryError:
# Linux kernel older than 3.11 ignores the O_TMPFILE flag:
# O_TMPFILE is read as O_DIRECTORY. Trying to open a directory
Expand All @@ -620,24 +642,25 @@ def TemporaryFile(mode='w+b', buffering=-1, encoding=None,
# fails with NotADirectoryError, because O_TMPFILE is read as
# O_DIRECTORY.
pass
else:
try:
return _io.open(fd, mode, buffering=buffering,
newline=newline, encoding=encoding,
errors=errors)
except:
_os.close(fd)
raise
# Fallback to _mkstemp_inner().

(fd, name) = _mkstemp_inner(dir, prefix, suffix, flags, output_type)
try:
_os.unlink(name)
return _io.open(fd, mode, buffering=buffering,
newline=newline, encoding=encoding, errors=errors)
except:
_os.close(fd)
raise
fd = None
def opener(*args):
nonlocal fd
fd, name = _mkstemp_inner(dir, prefix, suffix, flags, output_type)
try:
_os.unlink(name)
except BaseException as e:
_os.close(fd)
raise
return fd
file = _io.open(dir, mode, buffering=buffering,
newline=newline, encoding=encoding, errors=errors,
opener=opener)
raw = getattr(file, 'buffer', file)
raw = getattr(raw, 'raw', raw)
raw.name = fd
return file

class SpooledTemporaryFile(_io.IOBase):
"""Temporary file wrapper, specialized to switch from BytesIO
Expand Down
90 changes: 54 additions & 36 deletions Lib/test/test_tempfile.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -285,19 +285,14 @@ def our_candidate_list():
def raise_OSError(*args, **kwargs):
raise OSError()

with support.swap_attr(io, "open", raise_OSError):
# test again with failing io.open()
with support.swap_attr(os, "open", raise_OSError):
# test again with failing os.open()
with self.assertRaises(FileNotFoundError):
tempfile._get_default_tempdir()
self.assertEqual(os.listdir(our_temp_directory), [])

def bad_writer(*args, **kwargs):
fp = orig_open(*args, **kwargs)
fp.write = raise_OSError
return fp

with support.swap_attr(io, "open", bad_writer) as orig_open:
# test again with failing write()
with support.swap_attr(os, "write", raise_OSError):
# test again with failing os.write()
with self.assertRaises(FileNotFoundError):
tempfile._get_default_tempdir()
self.assertEqual(os.listdir(our_temp_directory), [])
Expand Down Expand Up @@ -978,6 +973,7 @@ def test_del_on_close(self):
try:
with tempfile.NamedTemporaryFile(dir=dir) as f:
f.write(b'blat')
self.assertEqual(os.listdir(dir), [])
self.assertFalse(os.path.exists(f.name),
"NamedTemporaryFile %s exists after close" % f.name)
finally:
Expand Down Expand Up @@ -1017,19 +1013,6 @@ def use_closed():
pass
self.assertRaises(ValueError, use_closed)

def test_no_leak_fd(self):
# Issue #21058: don't leak file descriptor when io.open() fails
closed = []
os_close = os.close
def close(fd):
closed.append(fd)
os_close(fd)

with mock.patch('os.close', side_effect=close):
with mock.patch('io.open', side_effect=ValueError):
self.assertRaises(ValueError, tempfile.NamedTemporaryFile)
self.assertEqual(len(closed), 1)

def test_bad_mode(self):
dir = tempfile.mkdtemp()
self.addCleanup(os_helper.rmtree, dir)
Expand All @@ -1039,6 +1022,24 @@ def test_bad_mode(self):
tempfile.NamedTemporaryFile(mode=2, dir=dir)
self.assertEqual(os.listdir(dir), [])

def test_bad_encoding(self):
dir = tempfile.mkdtemp()
self.addCleanup(os_helper.rmtree, dir)
with self.assertRaises(LookupError):
tempfile.NamedTemporaryFile('w', encoding='bad-encoding', dir=dir)
self.assertEqual(os.listdir(dir), [])

def test_unexpected_error(self):
dir = tempfile.mkdtemp()
self.addCleanup(os_helper.rmtree, dir)
with mock.patch('tempfile._TemporaryFileWrapper') as mock_ntf, \
mock.patch('io.open', mock.mock_open()) as mock_open:
mock_ntf.side_effect = KeyboardInterrupt()
with self.assertRaises(KeyboardInterrupt):
tempfile.NamedTemporaryFile(dir=dir)
mock_open().close.assert_called()
self.assertEqual(os.listdir(dir), [])

# How to test the mode and bufsize parameters?

class TestSpooledTemporaryFile(BaseTestCase):
Expand Down Expand Up @@ -1093,8 +1094,10 @@ def test_del_on_close(self):
self.assertTrue(f._rolled)
filename = f.name
f.close()
self.assertFalse(isinstance(filename, str) and os.path.exists(filename),
"SpooledTemporaryFile %s exists after close" % filename)
self.assertEqual(os.listdir(dir), [])
if not isinstance(filename, int):
self.assertFalse(os.path.exists(filename),
"SpooledTemporaryFile %s exists after close" % filename)
finally:
os.rmdir(dir)

Expand Down Expand Up @@ -1411,19 +1414,34 @@ def roundtrip(input, *args, **kwargs):
roundtrip("\u039B", "w+", encoding="utf-16")
roundtrip("foo\r\n", "w+", newline="")

def test_no_leak_fd(self):
# Issue #21058: don't leak file descriptor when io.open() fails
closed = []
os_close = os.close
def close(fd):
closed.append(fd)
os_close(fd)

with mock.patch('os.close', side_effect=close):
with mock.patch('io.open', side_effect=ValueError):
self.assertRaises(ValueError, tempfile.TemporaryFile)
self.assertEqual(len(closed), 1)
def test_bad_mode(self):
dir = tempfile.mkdtemp()
self.addCleanup(os_helper.rmtree, dir)
with self.assertRaises(ValueError):
tempfile.TemporaryFile(mode='wr', dir=dir)
with self.assertRaises(TypeError):
tempfile.TemporaryFile(mode=2, dir=dir)
self.assertEqual(os.listdir(dir), [])

def test_bad_encoding(self):
dir = tempfile.mkdtemp()
self.addCleanup(os_helper.rmtree, dir)
with self.assertRaises(LookupError):
tempfile.TemporaryFile('w', encoding='bad-encoding', dir=dir)
self.assertEqual(os.listdir(dir), [])

def test_unexpected_error(self):
dir = tempfile.mkdtemp()
self.addCleanup(os_helper.rmtree, dir)
with mock.patch('tempfile._O_TMPFILE_WORKS', False), \
mock.patch('os.unlink') as mock_unlink, \
mock.patch('os.open') as mock_open, \
mock.patch('os.close') as mock_close:
mock_unlink.side_effect = KeyboardInterrupt()
with self.assertRaises(KeyboardInterrupt):
tempfile.TemporaryFile(dir=dir)
mock_close.assert_called()
self.assertEqual(os.listdir(dir), [])


# Helper for test_del_on_shutdown
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2022-06-15-21-28-16.gh-issue-83499.u3DQJ-.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Fix double closing of file description in :mod:`tempfile`.

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