Convert the _imp extension module to the multi-phase initialization
API (PEP 489).
* Add _PyImport_BootstrapImp() which fix a bootstrap issue: import
the _imp module before importlib is initialized.
* Add create_builtin() sub-function, used by _imp_create_builtin().
* Initialize PyInterpreterState.import_func earlier, in
pycore_init_builtins().
* Remove references to _PyImport_Cleanup(). This function has been
renamed to finalize_modules() and moved to pylifecycle.c.
This change partically reverts
commit ad3252bad9
and the commit fe2978b3b9.
Many third party C extension modules rely on the ability of using
Py_TYPE() to set an object type: "Py_TYPE(obj) = type;" or to set an
object type using: "Py_SIZE(obj) = size;".
* Add signal_add_constants() function and add ADD_INT_MACRO macro.
* The Python SIGINT handler is now installed at the end of
signal_exec().
* Use Py_NewRef().
bpo-41686, bpo-41713: On Windows, the SIGINT event,
_PyOS_SigintEvent(), is now created even if Python is configured to
not install signal handlers (PyConfig.install_signal_handlers=0 or
Py_InitializeEx(0)).
Changes:
* Move global variables initialization from signal_exec() to
_PySignal_Init() to clarify that they are global variables cleared
by _PySignal_Fini().
* _PySignal_Fini() now closes sigint_event.
* IntHandler is no longer a global variable.
Remove the undocumented PyOS_InitInterrupts() C function.
* Rename PyOS_InitInterrupts() to _PySignal_Init(). It now installs
other signal handlers, not only SIGINT.
* Rename PyOS_FiniInterrupts() to _PySignal_Fini()
As AIX 5.3 and below do not support thread_cputime, it was decided in
https://bugs.python.org/issue40680 to require AIX 6.1 and above. This
commit removes workarounds for — and references to — older, unsupported
AIX versions.
time.time(), time.perf_counter() and time.monotonic() functions can
no longer fail with a Python fatal error, instead raise a regular
Python exception on failure.
Remove _PyTime_Init(): don't check system, monotonic and perf counter
clocks at startup anymore.
On error, _PyTime_GetSystemClock(), _PyTime_GetMonotonicClock() and
_PyTime_GetPerfCounter() now silently ignore the error and return 0.
They cannot fail with a Python fatal error anymore.
Add py_mach_timebase_info() and win_perf_counter_frequency()
sub-functions.
Explicitly cast PyExc_Exception to PyTypeObject* to fix the warning:
modules\_ctypes\_ctypes.c(5748): warning C4133: '=':
incompatible types - from 'PyObject *' to '_typeobject *'
It is no longer possible to build the _ctypes extension module
without wchar_t type: remove CTYPES_UNICODE macro. Anyway, the
wchar_t type is required to build Python.
Fix reference leaks in the error path of the initialization function
the _ctypes extension module: call Py_DECREF(mod) on error.
Change PyCFuncPtr_Type name from _ctypes.PyCFuncPtr to
_ctypes.CFuncPtr to be consistent with the name exposed in the
_ctypes namespace (_ctypes.CFuncPtr).
Split PyInit__ctypes() function into sub-functions and add macros for
readability.
Co-authored-by: Lawrence D’Anna <lawrence_danna@apple.com>
* Add support for macOS 11 and Apple Silicon (aka arm64)
As a side effect of this work use the system copy of libffi on macOS, and remove the vendored copy
* Support building on recent versions of macOS while deploying to older versions
This allows building installers on macOS 11 while still supporting macOS 10.9.
The PyConfig_Read() function now only parses PyConfig.argv arguments
once: PyConfig.parse_argv is set to 2 after arguments are parsed.
Since Python arguments are strippped from PyConfig.argv, parsing
arguments twice would parse the application options as Python
options.
* Rework the PyConfig documentation.
* Fix _testinternalcapi.set_config() error handling.
* SetConfigTests no longer needs parse_argv=0 when restoring the old
configuration.
* Rename _Py_GetLocaleEncoding() to _Py_GetLocaleEncodingObject()
* Add _Py_GetLocaleEncoding() which returns a wchar_t* string to
share code between _Py_GetLocaleEncodingObject()
and config_get_locale_encoding().
* _Py_GetLocaleEncodingObject() now decodes nl_langinfo(CODESET)
from the current locale encoding with surrogateescape,
rather than using UTF-8.
* bpo-42146: Unify cleanup in subprocess_fork_exec()
Also ignore errors from _enable_gc():
* They are always suppressed by the current code due to a bug.
* _enable_gc() is only used if `preexec_fn != None`, which is unsafe.
* We don't have a good way to handle errors in case we successfully
created a child process.
Co-authored-by: Gregory P. Smith <greg@krypto.org>
* Add a new _locale._get_locale_encoding() function to get the
current locale encoding.
* Modify locale.getpreferredencoding() to use it.
* Remove the _bootlocale module.
_io.TextIOWrapper no longer calls getpreferredencoding(False) of
_bootlocale to get the locale encoding, but calls
_Py_GetLocaleEncoding() instead.
Add config_get_fs_encoding() sub-function. Reorganize also
config_get_locale_encoding() code.
The last GC collection is now done before clearing builtins and sys
dictionaries. Add also assertions to ensure that gc.collect() is no
longer called after _PyGC_Fini().
Pass also the tstate to PyInterpreterState_Clear() to pass the
correct tstate to _PyGC_CollectNoFail() and _PyGC_Fini().
Move private _PyGC_CollectNoFail() to the internal C API.
Remove the private _PyGC_CollectIfEnabled() which was just an alias
to the public PyGC_Collect() function since Python 3.8.
Rename functions:
* collect() => gc_collect_main()
* collect_with_callback() => gc_collect_with_callback()
* collect_generations() => gc_collect_generations()
Use _PyLong_GetZero() and _PyLong_GetOne() in Modules/ directory.
_cursesmodule.c and zoneinfo.c are now built with
Py_BUILD_CORE_MODULE macro defined.
Removed the unicodedata.ucnhash_CAPI attribute which was an internal
PyCapsule object. The related private _PyUnicode_Name_CAPI structure
was moved to the internal C API.
Rename unicodedata.ucnhash_CAPI as unicodedata._ucnhash_CAPI.
Convert the unicodedata extension module to the multiphase
initialization API (PEP 489) and convert the unicodedata.UCD static
type to a heap type.
Co-Authored-By: Mohamed Koubaa <koubaa.m@gmail.com>
* UCD_Check() uses PyModule_Check()
* Simplify the internal _PyUnicode_Name_CAPI structure:
* Remove size and state members
* Remove state and self parameters of getcode() and getname()
functions
* Remove global_module_state
The private _PyUnicode_Name_CAPI structure of the PyCapsule API
unicodedata.ucnhash_CAPI moves to the internal C API. Moreover, the
structure gets a new state member which must be passed to the
getcode() and getname() functions.
* Move Include/ucnhash.h to Include/internal/pycore_ucnhash.h
* unicodedata module is now built with Py_BUILD_CORE_MODULE.
* unicodedata: move hashAPI variable into unicodedata_module_state.
If PyDict_GetItemWithError is only used to check whether the key is in dict,
it is better to use PyDict_Contains instead.
And if it is used in combination with PyDict_SetItem, PyDict_SetDefault can
replace the combination.
These functions are considered not safe because they suppress all internal errors
and can return wrong result. PyDict_GetItemString and _PyDict_GetItemId can
also silence current exception in rare cases.
Remove no longer used _PyDict_GetItemId.
Add _PyDict_ContainsId and rename _PyDict_Contains into
_PyDict_Contains_KnownHash.
Fix memory leak in subprocess.Popen() in case of uid/gid overflow
Also add a test that would catch this leak with `--huntrleaks`.
Alas, the test for `extra_groups` also exposes an inconsistency
in our error reporting: we use a custom ValueError for `extra_groups`,
but propagate OverflowError for `user` and `group`.
It should just be a syscall updating a couple of fields in the kernel side
process info. Confirming, in glibc is appears to be a shim for the setsid
syscall (based on not finding any code implementing anything special for it)
and in uclibc (*much* easier to read) it is clearly just a setsid syscall shim.
A breadcrumb _suggesting_ that it is not allowed on Darwin/macOS comes from
a commit in emacs: https://lists.gnu.org/archive/html/bug-gnu-emacs/2017-04/msg00297.html
but I don't have a way to verify if that is true or not.
As we are not supporting vfork on macOS today I just left a note in a comment.
Using POSIX_CALL() is incorrect since pthread_sigmask() returns
the error number instead of setting errno.
Also handle failure of the first call to pthread_sigmask()
in the parent process, and explain why we don't handle failure
of the second call in a comment.
* bpo-35823: subprocess: Use vfork() instead of fork() on Linux when safe
When used to run a new executable image, fork() is not a good choice
for process creation, especially if the parent has a large working set:
fork() needs to copy page tables, which is slow, and may fail on systems
where overcommit is disabled, despite that the child is not going to
touch most of its address space.
Currently, subprocess is capable of using posix_spawn() instead, which
normally provides much better performance. However, posix_spawn() does not
support many of child setup operations exposed by subprocess.Popen().
Most notably, it's not possible to express `close_fds=True`, which
happens to be the default, via posix_spawn(). As a result, most users
can't benefit from faster process creation, at least not without
changing their code.
However, Linux provides vfork() system call, which creates a new process
without copying the address space of the parent, and which is actually
used by C libraries to efficiently implement posix_spawn(). Due to sharing
of the address space and even the stack with the parent, extreme care
is required to use vfork(). At least the following restrictions must hold:
* No signal handlers must execute in the child process. Otherwise, they
might clobber memory shared with the parent, potentially confusing it.
* Any library function called after vfork() in the child must be
async-signal-safe (as for fork()), but it must also not interact with any
library state in a way that might break due to address space sharing
and/or lack of any preparations performed by libraries on normal fork().
POSIX.1 permits to call only execve() and _exit(), and later revisions
remove vfork() specification entirely. In practice, however, almost all
operations needed by subprocess.Popen() can be safely implemented on
Linux.
* Due to sharing of the stack with the parent, the child must be careful
not to clobber local variables that are alive across vfork() call.
Compilers are normally aware of this and take extra care with vfork()
(and setjmp(), which has a similar problem).
* In case the parent is privileged, special attention must be paid to vfork()
use, because sharing an address space across different privilege domains
is insecure[1].
This patch adds support for using vfork() instead of fork() on Linux
when it's possible to do safely given the above. In particular:
* vfork() is not used if credential switch is requested. The reverse case
(simple subprocess.Popen() but another application thread switches
credentials concurrently) is not possible for pure-Python apps because
subprocess.Popen() and functions like os.setuid() are mutually excluded
via GIL. We might also consider to add a way to opt-out of vfork() (and
posix_spawn() on platforms where it might be implemented via vfork()) in
a future PR.
* vfork() is not used if `preexec_fn != None`.
With this change, subprocess will still use posix_spawn() if possible, but
will fallback to vfork() on Linux in most cases, and, failing that,
to fork().
[1] https://ewontfix.com/7
Co-authored-by: Gregory P. Smith [Google LLC] <gps@google.com>
* Add F_SETPIPE_SZ and F_GETPIPE_SZ to fcntl module
* Add pipesize parameter for subprocess.Popen class
This will allow the user to control the size of the pipes.
On linux the default is 64K. When a pipe is full it blocks for writing.
When a pipe is empty it blocks for reading. On processes that are
very fast this can lead to a lot of wasted CPU cycles. On a typical
Linux system the max pipe size is 1024K which is much better.
For high performance-oriented libraries such as xopen it is nice to
be able to set the pipe size.
The workaround without this feature is to use my_popen_process.stdout.fileno() in
conjuction with fcntl and 1031 (value of F_SETPIPE_SZ) to acquire this behavior.
Prepare unicodedata to add a state per module: start with a global
"module" state, pass it to subfunctions which access &UCD_Type. This
change also prepares the conversion of the UCD_Type static type to a
heap type.
This API is relatively lightweight and organizationally, given that it's
used by multiple modules, it makes sense to move it to fileutils.
Requires making sure that _posixsubprocess is compiled with the appropriate
Py_BUIILD_CORE_BUILTIN macro.
This suppression is no longer needed in os_closerange_impl, as it just
invokes the internal _Py_closerange implementation. On the other hand,
consumers of _Py_closerange may not have any other reason to suppress
invalid parameter issues, so narrow the scope to here.
close_range(2) should be preferred at all times if it's available, otherwise we'll use closefrom(2) if available with a fallback to fdwalk(3) or plain old loop over fd range in order of most efficient to least.
[note that this version does check for ENOSYS, but currently ignores all other errors]
Automerge-Triggered-By: @pablogsal
Such an API can be used both for os.closerange and subprocess. For the latter, this yields potential improvement for platforms that have fdwalk but wouldn't have used it there. This will prove even more beneficial later for platforms that have close_range(2), as the new API will prefer that over all else if it's available.
The new API is structured to look more like close_range(2), closing from [start, end] rather than the [low, high) of os.closerange().
Automerge-Triggered-By: @gpshead
* bpo-26680: Adds support for int.is_integer() for compatibility with float.is_integer().
The int.is_integer() method always returns True.
* bpo-26680: Adds a test to ensure that False.is_integer() and True.is_integer() are always True.
* bpo-26680: Adds Real.is_integer() with a trivial implementation using conversion to int.
This default implementation is intended to reduce the workload for subclass
implementers. It is not robust in the presence of infinities or NaNs and
may have suboptimal performance for other types.
* bpo-26680: Adds Rational.is_integer which returns True if the denominator is one.
This implementation assumes the Rational is represented in it's
lowest form, as required by the class docstring.
* bpo-26680: Adds Integral.is_integer which always returns True.
* bpo-26680: Adds tests for Fraction.is_integer called as an instance method.
The tests for the Rational abstract base class use an unbound
method to sidestep the inability to directly instantiate Rational.
These tests check that everything works correct as an instance method.
* bpo-26680: Updates documentation for Real.is_integer and built-ins int and float.
The call x.is_integer() is now listed in the table of operations
which apply to all numeric types except complex, with a reference
to the full documentation for Real.is_integer(). Mention of
is_integer() has been removed from the section 'Additional Methods
on Float'.
The documentation for Real.is_integer() describes its purpose, and
mentions that it should be overridden for performance reasons, or
to handle special values like NaN.
* bpo-26680: Adds Decimal.is_integer to the Python and C implementations.
The C implementation of Decimal already implements and uses
mpd_isinteger internally, we just expose the existing function to
Python.
The Python implementation uses internal conversion to integer
using to_integral_value().
In both cases, the corresponding context methods are also
implemented.
Tests and documentation are included.
* bpo-26680: Updates the ACKS file.
* bpo-26680: NEWS entries for int, the numeric ABCs and Decimal.
Co-authored-by: Robert Smallshire <rob@sixty-north.com>
Use _PyType_HasFeature() in the _io module and in structseq
implementation. Replace PyType_HasFeature() opaque function call with
_PyType_HasFeature() inlined function.
The new API allows to efficiently send values into native generators
and coroutines avoiding use of StopIteration exceptions to signal
returns.
ceval loop now uses this method instead of the old "private"
_PyGen_Send C API. This translates to 1.6x increased performance
of 'await' calls in micro-benchmarks.
Aside from CPython core improvements, this new API will also allow
Cython to generate more efficient code, benefiting high-performance
IO libraries like uvloop.
* When the parameters argument is a list, correctly handle the case
of changing it during iteration.
* When the parameters argument is a custom sequence, no longer
override an exception raised in ``__len__()``.
I just realized that my recent PR with sendfile on Solaris ([PR 22040](https://github.com/python/cpython/pull/22040)) has broken error handling.
Sorry for that, this simple followup fixes that.
Automerge-Triggered-By: @1st1
siginterrupt is deprecated:
./Modules/signalmodule.c:667:5: warning: ‘siginterrupt’ is deprecated: Use sigaction with SA_RESTART instead [-Wdeprecated-declarations]
667 | if (siginterrupt(signalnum, flag)<0) {
* Fix refleak in C module __init_subclass__
This was leaking a reference to the weak cache dictionary for every
ZoneInfo subclass created.
* Fix refleak in ZoneInfo subclass's clear_cache
The previous version of the code accidentally cleared the global
ZONEINFO_STRONG_CACHE variable (and inducing `ZoneInfo` to create a new
strong cache) on calls to a subclass's `clear_cache()`. This would not
affect guaranteed behavior, but it's still not the right thing to do
(and it caused reference leaks).
[bpo-31122](): ssl.wrap_socket() now raises ssl.SSLEOFError rather than OSError when peer closes connection during TLS negotiation
Reproducer: http://tiny.cc/f4ztnz (tiny url because some bot keeps renaming b.p.o.-nnn as bpo links)
Prior to this change, attempting to subclass the C implementation of
zoneinfo.ZoneInfo gave the following error:
TypeError: unbound method ZoneInfo.__init_subclass__() needs an argument
https://bugs.python.org/issue41025
* Merge gen and frame state variables into one.
* Replace stack pointer with depth in PyFrameObject. Makes code easier to read and saves a word of memory.
Add an accessor under SSLContext.security_level as a wrapper around
SSL_CTX_get_security_level, see:
https://www.openssl.org/docs/manmaster/man3/SSL_CTX_get_security_level.html
------
This is my first time contributing, so please pull me up on all the things I missed or did incorrectly.
Automerge-Triggered-By: @tiran
Move definition of UNUSED from modified headers of libmpdec to
_decimal.c itself. This makes the vendored source closer to the
standalone library and fixes build with --with-system-libmpdec.
Tested to build fine with either system libmpdec or the vendored one.
The running loop holder cache variable was always set to NULL when
calling set_running_loop.
Now set_running_loop saves the newly created running loop holder in the
cache variable for faster access in get_running_loop.
Automerge-Triggered-By: @1st1
Each interpreter now has its own dict free list:
* Move dict free lists into PyInterpreterState.
* Move PyDict_MAXFREELIST define to pycore_interp.h
* Add _Py_dict_state structure.
* Add tstate parameter to _PyDict_ClearFreeList() and _PyDict_Fini().
* In debug mode, ensure that the dict free lists are not used after
_PyDict_Fini() is called.
* Remove "#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS".
There are a bunch of other fd: int uses in this file, I expect many if not
all of them would be better off using the fildes converter. This particular
one was flagged by Coverity as it presumably flags fpathconf as not accepting
negative fds. I'd expect the other fd's to have been flagged as well
otherwise.
I'm marking this one as skip news as it really is a no-op.
The PY_SSIZE_T_CLEAN macro must now be defined to use
PyArg_ParseTuple() and Py_BuildValue() "#" formats: "es#", "et#",
"s#", "u#", "y#", "z#", "U#" and "Z#". See the PEP 353.
Update _testcapi.test_buildvalue_issue38913().
The PyObject_INIT() and PyObject_INIT_VAR() macros become aliases to,
respectively, PyObject_Init() and PyObject_InitVar() functions.
Rename _PyObject_INIT() and _PyObject_INIT_VAR() static inline
functions to, respectively, _PyObject_Init() and _PyObject_InitVar(),
and move them to pycore_object.h. Remove their return value:
their return type becomes void.
The _datetime module is now built with the Py_BUILD_CORE_MODULE macro
defined.
Remove an outdated comment on _Py_tracemalloc_config.
On Windows, #include "pyerrors.h" no longer defines "snprintf" and
"vsnprintf" macros.
PyOS_snprintf() and PyOS_vsnprintf() should be used to get portable
behavior.
Replace snprintf() calls with PyOS_snprintf() and replace vsnprintf()
calls with PyOS_vsnprintf().
In GH-2866, _Py_Bit_Length() was added to pymath.h for lack of a better
location. GH-20518 added a more appropriate header file for bit utilities. It
also shows how to properly use intrinsics. This allows reconsidering bpo-29782.
* Move the function to the new header.
* Changed return type to match __builtin_clzl() and reviewed usage.
* Use intrinsics where available.
* Pick a fallback implementation suitable for inlining.
```
Direct leak of 8 byte(s) in 1 object(s) allocated from:
#0 0x7f008bf19667 in __interceptor_malloc (/lib64/libasan.so.6+0xb0667)
#1 0x7f007a0bee4a in subprocess_fork_exec /home/heimes/dev/python/cpython/Modules/_posixsubprocess.c:774
#2 0xe0305b in cfunction_call Objects/methodobject.c:546
```
Signed-off-by: Christian Heimes <christian@python.org>
This commit removes the old parser, the deprecated parser module, the old parser compatibility flags and environment variables and all associated support code and documentation.
Followup of bpo-40854, there is one remaining usage of PLATLIBDIR
which should be replaced by config->platlibdir.
test_sys checks that sys.platlibdir attribute exists and is a string.
Update Makefile: getpath.c and sysmodule.c no longer need PLATLIBDIR
macro, PyConfig.platlibdir member is used instead.
Co-authored-by: Sandro Mani <manisandro@gmail.com>
The PEP 353, written in 2005, introduced PY_FORMAT_SIZE_T. Python no
longer supports macOS 10.4 and Visual Studio 2010, but requires more
recent macOS and Visual Studio versions. In 2020 with Python 3.10, it
is now safe to use directly "%zu" to format size_t and "%zi" to
format Py_ssize_t.
* Rename pycore_byteswap.h to pycore_bitutils.h.
* Move popcount_digit() to pycore_bitutils.h as _Py_popcount32().
* _Py_popcount32() uses GCC and clang builtin function if available.
* Add unit tests to _Py_popcount32().
Each interpreter now has its own context free list:
* Move context free list into PyInterpreterState.
* Add _Py_context_state structure.
* Add tstate parameter to _PyContext_ClearFreeList()
and _PyContext_Fini().
* Pass tstate to clear_freelists().
Each interpreter now has its own asynchronous generator free lists:
* Move async gen free lists into PyInterpreterState.
* Move _PyAsyncGen_MAXFREELIST define to pycore_interp.h
* Add _Py_async_gen_state structure.
* Add tstate parameter to _PyAsyncGen_ClearFreeLists
and _PyAsyncGen_Fini().
Each interpreter now has its own list free list:
* Move list numfree and free_list into PyInterpreterState.
* Add _Py_list_state structure.
* Add tstate parameter to _PyList_ClearFreeList()
and _PyList_Fini().
* Remove "#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS".
* _PyGC_Fini() clears gcstate->garbage list which can be stored in
the list free list. Call _PyGC_Fini() before _PyList_Fini() to
prevent leaking this list.
Each interpreter now has its own frame free list:
* Move frame free list into PyInterpreterState.
* Add _Py_frame_state structure.
* Add tstate parameter to _PyFrame_ClearFreeList()
and _PyFrame_Fini().
* Remove "#if PyFrame_MAXFREELIST > 0".
* Remove "#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS".
Each interpreter now has its own float free list:
* Move tuple numfree and free_list into PyInterpreterState.
* Add _Py_float_state structure.
* Add tstate parameter to _PyFloat_ClearFreeList()
and _PyFloat_Fini().
Each interpreter now has its own tuple free lists:
* Move tuple numfree and free_list arrays into PyInterpreterState.
* Define PyTuple_MAXSAVESIZE and PyTuple_MAXFREELIST macros in
pycore_interp.h.
* Add _Py_tuple_state structure. Pass it explicitly to tuple_alloc().
* Add tstate parameter to _PyTuple_ClearFreeList()
* Each interpreter now has its own empty tuple singleton.
my_fgets() now calls _PyOS_InterruptOccurred(tstate) to check for
pending signals, rather calling PyOS_InterruptOccurred().
my_fgets() is called with the GIL released, whereas
PyOS_InterruptOccurred() must be called with the GIL held.
test_repl: use text=True and avoid SuppressCrashReport in
test_multiline_string_parsing().
Fix my_fgets() on Windows: fgets(fp) does crash if fileno(fp) is closed.
PyOS_AfterFork_Child() helper functions now return a PyStatus:
PyOS_AfterFork_Child() is now responsible to handle errors.
* Move _PySignal_AfterFork() to the internal C API
* Add #ifdef HAVE_FORK on _PyGILState_Reinit(), _PySignal_AfterFork()
and _PyInterpreterState_DeleteExceptMain().
Fix :mod:`ssl`` code to be compatible with OpenSSL 1.1.x builds that use
``no-deprecated`` and ``--api=1.1.0``.
Note: Tests assume full OpenSSL API and fail with limited API.
Signed-off-by: Christian Heimes <christian@python.org>
Co-authored-by: Mark Wright <gienah@gentoo.org>
Recent changes to _datetimemodule broke compilation on mingw; see the comments in this change for details.
FWIW, @corona10: this issue is why `PyType_FromModuleAndSpec` & friends take the `bases` argument at run time.
On macOS, socket.getaddrinfo() no longer uses an internal lock to
prevent race conditions when calling getaddrinfo(). getaddrinfo is
thread-safe is macOS 10.5, whereas Python 3.9 requires macOS 10.6 or
newer.
The lock was also used on FreeBSD older than 5.3, OpenBSD older than
201311 and NetBSD older than 4.