Fix a race condition in test_check_output_timeout() of
test_subprocess. Don't write into stdout anymore, since there is no
reliable way to synchronize the parent and the child processes.
Change the timeout from 3 seconds to 0.1 seconds, and remove
@requires_resource('walltime') decorator.
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
Explicitly handle the case where stdout=STDOUT
as otherwise the existing error handling gets
confused and reports hard to understand errors.
Signed-off-by: Paulo Neves <ptsneves@gmail.com>
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.
* gh-104522: Fix test_subprocess failure when build Python in the root home directory
EPERM is raised when setreuid() fails.
EACCES is set in execve() when the test user has not access to sys.executable.
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>
* improve the assert for test_one_environment_variable
* skip some test in test_subprocess when python is configured with shared
* also skip the test if AddressSanitizer is enabled
---------
Co-authored-by: Steve Dower <steve.dower@microsoft.com>
Add support for `os.POSIX_SPAWN_CLOSEFROM` and
`posix_spawn_file_actions_addclosefrom_np` and have the `subprocess` module use
them when available. This means `posix_spawn` can now be used in the default
`close_fds=True` situation on many platforms.
Co-authored-by: Gregory P. Smith [Google LLC] <greg@krypto.org>
Regression test that vfork is used when expected by subprocess.
This is written integration test style, it uses strace if it is present and appears to work to find out what system call actually gets used in different scenarios.
Test coverage is added for the default behavior and that of each of the specific arguments that must disable the use of vfork. obviously not an entire test matrix, but it covers the most important aspects.
If there are ever issues with this test being flaky or failing on new platforms, rather than try and adapt it for all possible platforms, feel free to narrow the range it gets tested on when appropriate. That is not likely to reduce coverage.
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>
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>
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>
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.
Removes the `list` call in the Popen `repr`.
Current implementation:
For cmd = `python --version`, with `shell=True`.
```bash
<Popen: returncode: None args: ['p', 'y', 't', 'h', 'o', 'n', ' ', '-', '-',...>
```
For `shell=False` and args=`['python', '--version']`, the output is correct:
```bash
<Popen: returncode: None args: ['python', '--version']>
```
With the new changes the `repr` yields:
For cmd = `python --version`, with `shell=True`:
```bash
<Popen: returncode: None args: 'python --version'>
```
For `shell=False` and args=`['python', '--version']`, the output:
```bash
<Popen: returncode: None args: ['python', '--version']>
```
Automerge-Triggered-By: GH:gpshead
When the modern text= spelling of the universal_newlines= parameter was added
for Python 3.7, check_output's special case around input=None was overlooked.
So it behaved differently with universal_newlines=True vs text=True. This
reconciles the behavior to be consistent and adds a test to guarantee it.
Also clarifies the existing check_output documentation.
Co-authored-by: Alexey Izbyshev <izbyshev@ispras.ru>
send_signal() now swallows the exception if the process it thought was still alive winds up not to exist anymore (always a plausible race condition despite the checks).
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`.
