This fixes several ways file descriptors could be leaked from `subprocess.Popen` constructor during error conditions by opening them later and using a context manager "fds to close" registration scheme to ensure they get closed before returning.
---------
Co-authored-by: Gregory P. Smith [Google] <greg@krypto.org>
Add the -P command line option and the PYTHONSAFEPATH environment
variable to not prepend a potentially unsafe path to sys.path.
* Add sys.flags.safe_path flag.
* Add PyConfig.safe_path member.
* Programs/_bootstrap_python.c uses config.safe_path=0.
* Update subprocess._optim_args_from_interpreter_flags() to handle
the -P command line option.
* Modules/getpath.py sets safe_path to 1 if a "._pth" file is
present.
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
See [PEP 597](https://www.python.org/dev/peps/pep-0597/).
* Add `-X warn_default_encoding` and `PYTHONWARNDEFAULTENCODING`.
* Add EncodingWarning
* Add io.text_encoding()
* open(), TextIOWrapper() emits EncodingWarning when encoding is omitted and warn_default_encoding is enabled.
* _pyio.TextIOWrapper() uses UTF-8 as fallback default encoding used when failed to import locale module. (used during building Python)
* bz2, configparser, gzip, lzma, pathlib, tempfile modules use io.text_encoding().
* What's new entry
Check to make sure stdout and stderr are not empty before selecting an item from them in Windows subprocess._communicate.
Co-authored-by: Gregory P. Smith <greg@krypto.org>
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>
* 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.
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.
* Rename PyConfig.use_peg to _use_peg_parser
* Document PyConfig._use_peg_parser and mark it a deprecated
* Mark -X oldparser option and PYTHONOLDPARSER env var as deprecated
in the documentation.
* Add use_old_parser() and skip_if_new_parser() to test.support
* Remove sys.flags.use_peg: use_old_parser() uses
_testinternalcapi.get_configs() instead.
* Enhance test_embed tests
* subprocess._args_from_interpreter_flags() copies -X oldparser
This implements things like `list[int]`,
which returns an object of type `types.GenericAlias`.
This object mostly acts as a proxy for `list`,
but has attributes `__origin__` and `__args__`
that allow recovering the parts (with values `list` and `(int,)`.
There is also an approximate notion of type variables;
e.g. `list[T]` has a `__parameters__` attribute equal to `(T,)`.
Type variables are objects of type `typing.TypeVar`.
Add os.waitstatus_to_exitcode() function to convert a wait status to an
exitcode.
Suggest waitstatus_to_exitcode() usage in the documentation when
appropriate.
Use waitstatus_to_exitcode() in:
* multiprocessing, os, subprocess and _bootsubprocess modules;
* test.support.wait_process();
* setup.py: run_command();
* and many tests.
When communicate() is called in a loop, it crashes when the child process
has already closed any piped standard stream, but still continues to be running
Co-authored-by: Andriy Maletsky <andriy.maletsky@gmail.com>
On Unix, subprocess.Popen.send_signal() now polls the process status.
Polling reduces the risk of sending a signal to the wrong process if
the process completed, the Popen.returncode attribute is still None,
and the pid has been reassigned (recycled) to a new different
process.
* subprocess.Popen now longer uses posix_spawn() if uid, gid or gids are set.
* test_subprocess: add "nobody" and "nfsnobody" group names for test_group().
* test_subprocess: test_user() and test_group() are now also tested with close_fds=False.
* subprocess: Add user, group and extra_groups paremeters to subprocess.Popen
This adds a `user` parameter to the Popen constructor that will call
setreuid() in the child before calling exec(). This allows processes
running as root to safely drop privileges before running the subprocess
without having to use a preexec_fn.
This also adds a `group` parameter that will call setregid() in
the child process before calling exec().
Finally an `extra_groups` parameter was added that will call
setgroups() to set the supplimental groups.
Fixes a possible hang when using a timeout on subprocess.run() while
capturing output. If the child process spawned its own children or otherwise
connected its stdout or stderr handles with another process, we could hang
after the timeout was reached and our child was killed when attempting to read
final output from the pipes.
As noted by @eryksun in [1] and [2], using _cleanup and _active(in
__del__) is not necessary on Windows, since:
> Unlike Unix, a process in Windows doesn't have to be waited on by
> its parent to avoid a zombie. Keeping the handle open will actually
> create a zombie until the next _cleanup() call, which may be never
> if Popen() isn't called again.
This patch simply defines `subprocess._active` as `None`, for which we already
have the proper logic in place in `subprocess.Popen.__del__`, that prevents it
from trying to append the process to the `_active`. This patch also defines
`subprocess._cleanup` as a noop for Windows.
[1] https://bugs.python.org/issue37380#msg346333
[2] https://bugs.python.org/issue36067#msg336262
Signed-off-by: Ruslan Kuprieiev <ruslan@iterative.ai>
Fix an unintended ValueError from :func:`subprocess.run` when checking for
conflicting `input` and `stdin` or `capture_output` and `stdout` or `stderr` args
when they were explicitly provided but with `None` values within a passed in
`**kwargs` dict rather than as passed directly by name.
Close pipes/fds in subprocess by using ExitStack.
"In case of premature failure on X.Close() or os.close(X) the remaining pipes/fds will remain "open". Perhaps it makes sense to use contextlib.ExitStack."
- Rationale: https://github.com/python/cpython/pull/11575#discussion_r250288394
* subprocess.Popen can now also use os.posix_spawn() with pipes,
but only if pipe file descriptors are greater than 2.
* Fix Popen._posix_spawn(): set '_child_created' attribute to True.
* Add Popen._close_pipe_fds() helper function to factorize the code.
The subprocess module can now use the os.posix_spawn() function
in some cases for better performance. Currently, it is only used on macOS
and Linux (using glibc 2.24 or newer) if all these conditions are met:
* executable path contains a directory
* close_fds=False
* preexec_fn, pass_fds, cwd, stdin, stdout, stderr
and start_new_session parameters are not set
Co-authored-by: Joannah Nanjekye <nanjekyejoannah@gmail.com>
cptpcrd
Steve Dower
Oleg Iarygin
andrei kulakov
Christian Heimes
Victor Stinner
Gregory P. Smith
Inada Naoki
Rémi Lapeyre
Jakub Kulík
Binbin
M. Kocher
Chris Griffith
Kamil Turek
Filipe Laíns
Ruben Vorderman
Pablo Galindo
Guido van Rossum
Alex Rebert
Batuhan Taşkaya
Andrey Doroschenko
Victor Stinner
Patrick McLean
Matthias
Ruslan Kuprieiev
Rémi Lapeyre
Serhiy Storchaka
Giampaolo Rodola