The pid_t, Py_off_t, HANDLE, DWORD and BOOL converters were defined in
9 files. The Py_off_t type and its converter function are now shared too.
DWORD in _winapi is used with bitwise=True to keep accepting negative
values.
The pid_t converter is now used for the pid parameters in the
_remote_debugging module, which were declared as int.
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
Use glibc functions instead of syscall(): pidfd_open(), pidfd_getfd()
and pidfd_send_signal() (glibc 2.36), gettid() and getdents64()
(glibc 2.30), and getrandom() (glibc 2.25).
Use unsigned int for os.getrandom() flags and
signal.pidfd_send_signal() flags.
Rename from _Py_INTERNAL_ABI_SLOT to _Py_ABI_SLOT
and define the macro using _PyABIInfo_DEFAULT.
Use the ABI slot in stdlib extension modules to enable running
a check of ABI version compatibility.
_tkinter, _tracemalloc and readline don't use the slots, hence they need
explicit handling.
Co-authored-by: Victor Stinner <vstinner@python.org>
Add extra audit hooks to catch C function calling from ctypes,
reading/writing files through readline and executing external
programs through _posixsubprocess.
* Make audit-tests for open pass when readline.append_history_file is unavailable
* Less direct testing of _posixsubprocess for audit hooks
* Also remove the audit hook from call_cdeclfunction now that _ctypes_callproc does it instead.
* reword the NEWS entry.
* mention readline in NEWS
* add versionchanged markers
* fix audit_events.rst versionadded
* doc lint
---------
Co-authored-by: Gregory P. Smith <greg@krypto.org>
This flag was added as an escape hatch in gh-91401 and backported to
Python 3.10. The flag broke at some point between its addition and now.
As there is currently no publicly known environments that require this,
remove it rather than work on fixing it.
This leaves the flag in the subprocess module to not break code which
may have used / checked the flag itself.
discussion: https://discuss.python.org/t/subprocess-use-vfork-escape-hatch-broken-fix-or-remove/56915/2
This PR adds the ability to enable the GIL if it was disabled at
interpreter startup, and modifies the multi-phase module initialization
path to enable the GIL when loading a module, unless that module's spec
includes a slot indicating it can run safely without the GIL.
PEP 703 called the constant for the slot `Py_mod_gil_not_used`; I went
with `Py_MOD_GIL_NOT_USED` for consistency with gh-104148.
A warning will be issued up to once per interpreter for the first
GIL-using module that is loaded. If `-v` is given, a shorter message
will be printed to stderr every time a GIL-using module is loaded
(including the first one that issues a warning).
Starting in Python 3.12, we prevented calling fork() and starting new threads
during interpreter finalization (shutdown). This has led to a number of
regressions and flaky tests. We should not prevent starting new threads
(or `fork()`) until all non-daemon threads exit and finalization starts in
earnest.
This changes the checks to use `_PyInterpreterState_GetFinalizing(interp)`,
which is set immediately before terminating non-daemon threads.
Add PythonFinalizationError exception. This exception derived from
RuntimeError is raised when an operation is blocked during the Python
finalization.
The following functions now raise PythonFinalizationError, instead of
RuntimeError:
* _thread.start_new_thread()
* subprocess.Popen
* os.fork()
* os.fork1()
* os.forkpty()
Morever, _winapi.Overlapped finalizer now logs an unraisable
PythonFinalizationError, instead of an unraisable RuntimeError.
Only set filename to cwd if it was caused by failed chdir(cwd).
_fork_exec() now returns "noexec:chdir" for failed chdir(cwd).
Co-authored-by: Robert O'Shea <PurityLake@users.noreply.github.com>
Restore `subprocess`'s intended use of `vfork()` by default for performance on Linux;
also fixes the behavior of `extra_groups=[]` which was unintentionally broken in 3.12.0:
Fixed a performance regression in 3.12's :mod:`subprocess` on Linux where it
would no longer use the fast-path ``vfork()`` system call when it could have
due to a logic bug, instead falling back to the safe but slower ``fork()``.
Also fixed a security bug introduced in 3.12.0. If a value of ``extra_groups=[]``
was passed to :mod:`subprocess.Popen` or related APIs, the underlying
``setgroups(0, NULL)`` system call to clear the groups list would not be made
in the child process prior to ``exec()``.
The security issue was identified via code inspection in the process of
fixing the first bug. Thanks to @vain for the detailed report and
analysis in the initial bug on Github.
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Remove private pylifecycle.h functions: move them to the internal C
API ( pycore_atexit.h, pycore_pylifecycle.h and pycore_signal.h). No
longer export most of these functions.
Move _testcapi.test_atexit() to _testinternalcapi.
Remove private _PySequence_BytesToCharpArray() and
_Py_FreeCharPArray() functions from the public C API: move these
functions from Objects/abstract.c to Modules/_posixsubprocess.c.
Disallow thread creation and fork at interpreter finalization.
in the following functions, check if interpreter is finalizing and raise `RuntimeError` with appropriate message:
* `_thread.start_new_thread` and thus `threading`
* `posix.fork`
* `posix.fork1`
* `posix.forkpty`
* `_posixsubprocess.fork_exec` when a `preexec_fn=` is supplied.
---------
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>
On Linux where the `subprocess` module can use the `vfork` syscall for
faster spawning, prevent the parent process from blocking other threads
by dropping the GIL while it waits for the vfork'ed child process `exec`
outcome. This prevents spawning a binary from a slow filesystem from
blocking the rest of the application.
Fixes#104372.
Move all of the Python C API calls into the parent process up front
instead of doing PyLong_AsLong and PyErr_Occurred and PyTuple_GET from
the post-fork/vfork child process.
Much of this was long overdue. We shouldn't have been using PyTuple and
PyLong APIs within all of these low level functions anyways.
Here we are doing no more than adding the value for Py_mod_multiple_interpreters and using it for stdlib modules. We will start checking for it in gh-104206 (once PyInterpreterState.ceval.own_gil is added in gh-104204).
Have _posixsubprocess.c stop using boolean flags to say if gid and uid values were supplied and action is required. Such an implicit "either initialized or look somewhere else" confused both the reader (another mental connection to constantly track between functions) and a compiler (warnings on potentially uninitialized variables being passed). Instead, we can utilize a special group/user id as a flag value -1 defined by POSIX but used nowhere else. Namely:
gid: call_setgid = False → gid = -1
uid: call_setuid = False → uid = -1
groups: call_setgroups = False → groups = NULL (obtained with (groups_list != Py_None) ? groups : NULL)
This PR is required for #94519.
builtins and extension module functions and methods that expect boolean values for parameters now accept any Python object rather than just a bool or int type. This is more consistent with how native Python code itself behaves.
Previously, the optional restrictions on subinterpreters were: disallow fork, subprocess, and threads. By default, we were disallowing all three for "isolated" interpreters. We always allowed all three for the main interpreter and those created through the legacy `Py_NewInterpreter()` API.
Those settings were a bit conservative, so here we've adjusted the optional restrictions to: fork, exec, threads, and daemon threads. The default for "isolated" interpreters disables fork, exec, and daemon threads. Regular threads are allowed by default. We continue always allowing everything For the main interpreter and the legacy API.
In the code, we add `_PyInterpreterConfig.allow_exec` and `_PyInterpreterConfig.allow_daemon_threads`. We also add `Py_RTFLAGS_DAEMON_THREADS` and `Py_RTFLAGS_EXEC`.
(see https://github.com/python/cpython/issues/98608)
This change does the following:
1. change the argument to a new `_PyInterpreterConfig` struct
2. rename the function to `_Py_NewInterpreterFromConfig()`, inspired by `Py_InitializeFromConfig()` (takes a `_PyInterpreterConfig` instead of `isolated_subinterpreter`)
3. split up the boolean `isolated_subinterpreter` into the corresponding multiple granular settings
* allow_fork
* allow_subprocess
* allow_threads
4. add `PyInterpreterState.feature_flags` to store those settings
5. add a function for checking if a feature is enabled on an opaque `PyInterpreterState *`
6. drop `PyConfig._isolated_interpreter`
The existing default (see `Py_NewInterpeter()` and `Py_Initialize*()`) allows fork, subprocess, and threads and the optional "isolated" interpreter (see the `_xxsubinterpreters` module) disables all three. None of that changes here; the defaults are preserved.
Note that the given `_PyInterpreterConfig` will not be used outside `_Py_NewInterpreterFromConfig()`, nor preserved. This contrasts with how `PyConfig` is currently preserved, used, and even modified outside `Py_InitializeFromConfig()`. I'd rather just avoid that mess from the start for `_PyInterpreterConfig`. We can preserve it later if we find an actual need.
This change allows us to follow up with a number of improvements (e.g. stop disallowing subprocess and support disallowing exec instead).
(Note that this PR adds "private" symbols. We'll probably make them public, and add docs, in a separate change.)
One more thing that can help prevent people from using `preexec_fn`.
Also adds conditional skips to two tests exposing ASAN flakiness on the Ubuntu 20.04 Address Sanitizer Github CI system. When that build is run on more modern systems the "problem" does not show up. It seems ASAN implementation related.
Co-authored-by: Zackery Spytz <zspytz@gmail.com>
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
#92301: subprocess: Prefer `close_range()` to procfs-based fd closing.
`close_range()` is much faster for large number of file descriptors, e.g.
4 times faster for 1000 descriptors in a Linux 5.16-based environment.
We prefer close_range() only if it's known to be async-signal-safe.
Just in case there is ever an issue with _posixsubprocess's use of
vfork() due to the complexity of using it properly and potential
directions that Linux platforms where it defaults to on could take, this
adds a failsafe so that users can disable its use entirely by setting
a global flag.
No known reason to disable it exists. But it'd be a shame to encounter
one and not be able to use CPython without patching and rebuilding it.
See the linked issue for some discussion on reasoning.
Also documents the existing way to disable posix_spawn.
bpo-47151: Fallback to fork when vfork fails in subprocess. An OS kernel can specifically decide to disallow vfork() in a process. No need for that to prevent us from launching subprocesses.
setup.py no longer defines Py_BUILD_CORE_MODULE. Instead every
module defines the macro before #include "Python.h" unless
Py_BUILD_CORE_BUILTIN is already defined.
Py_BUILD_CORE_BUILTIN is defined for every module that is built by
Modules/Setup.
The PR also simplifies Modules/Setup. Makefile and makesetup
already define Py_BUILD_CORE_BUILTIN and include Modules/internal
for us.
Signed-off-by: Christian Heimes <christian@python.org>
* 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>
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`.
Zanie Blue