bpo-32844: subprocess: Fix a potential misredirection of a low fd to stderr.
When redirecting, subprocess attempts to achieve the following state:
each fd to be redirected to is less than or equal to the fd
it is redirected from, which is necessary because redirection
occurs in the ascending order of destination descriptors.
It fails to do so in a couple of corner cases,
for example, if 1 is redirected to 2 and 0 is closed in the parent.
Do not allow receiving a SIGINT to cause the subprocess module to trigger an
immediate SIGKILL of the child process. SIGINT is normally sent to all child
processes by the OS at the same time already as was the established normal
behavior in 2.7 and 3.2. This behavior change was introduced during the fix to https://bugs.python.org/issue12494 and is generally surprising to command line
tool users who expect other tools launched in child processes to get their own
SIGINT and do their own cleanup.
In Python 3.3-3.6 subprocess.call and subprocess.run would immediately
SIGKILL the child process upon receiving a SIGINT (which raises a
KeyboardInterrupt). We now give the child a small amount of time to
exit gracefully before resorting to a SIGKILL.
This is also the case for subprocess.Popen.__exit__ which would
previously block indefinitely waiting for the child to die. This was
hidden from many users by virtue of subprocess.call and subprocess.run
sending the signal immediately.
Behavior change: subprocess.Popen.__exit__ will not block indefinitely
when the exiting exception is a KeyboardInterrupt. This is done for
user friendliness as people expect their ^C to actually happen. This
could cause occasional orphaned Popen objects when not using `call` or
`run` with a child process that hasn't exited.
Refactoring involved: The Popen.wait method deals with the
KeyboardInterrupt second chance, existing platform specific internals
have been renamed to _wait().
Also fixes comment typos.
Some tests failed when the PATH environment variable contained a path
to an existing file. Fix tests to ignore also NotADirectoryError, not
only FileNotFoundError and PermissionError.
The last part of test_close_fds() doesn't match its own comment.
The following assertion always holds because fds_to_keep and open_fds
are disjoint by construction.
self.assertFalse(remaining_fds & fds_to_keep & open_fds,
"Some fds not in pass_fds were left open")
Fix the code to match the message in the assertion.
Even though Python marks any handles it opens as non-inheritable there
is still a race when using `subprocess.Popen` since creating a process
with redirected stdio requires temporarily creating inheritable handles.
By implementing support for `subprocess.Popen(close_fds=True)` we fix
this race.
In order to implement this we use PROC_THREAD_ATTRIBUTE_HANDLE_LIST
which is available since Windows Vista. Which allows to pass an explicit
list of handles to inherit when creating a process.
This commit also adds `STARTUPINFO.lpAttributeList["handle_list"]`
which can be used to control PROC_THREAD_ATTRIBUTE_HANDLE_LIST
directly.
Improve human friendliness of the Popen API: Add text=False as a
keyword-only argument to subprocess.Popen along with a Popen
attribute .text_mode and set this based on the
encoding/errors/universal_newlines/text arguments.
The universal_newlines parameter and attribute are maintained for
backwards compatibility.
Fix test_exception_errpipe_bad_data() and
test_exception_errpipe_normal() of test_subprocess: mock os.waitpid()
to avoid calling the real os.waitpid(0, 0) which is an unexpected
side effect of the test.
* bpo-30121: Fix debug assert in subprocess on Windows
This is caused by closing HANDLEs using os.close which is for CRT file
descriptors and not for HANDLEs.
* bpo-30121: Suppress debug assertion in test_subprocess when ran directly
The current test_child_terminated_in_stopped_state() function test
creates a child process which calls ptrace(PTRACE_TRACEME, 0, 0) and
then crash (SIGSEGV). The problem is that calling os.waitpid() in the
parent process is not enough to close the process: the child process
remains alive and so the unit test leaks a child process in a
strange state. Closing the child process requires non-trivial code,
maybe platform specific.
Remove the functional test and replaces it with an unit test which
mocks os.waitpid() using a new _testcapi.W_STOPCODE() function to
test the WIFSTOPPED() path.
bpo-30764, bpo-29335: test_child_terminated_in_stopped_state() of
test_subprocess now uses support.SuppressCrashReport() to prevent the
creation of a core dump on FreeBSD.
- new PYTHONCOERCECLOCALE config setting
- coerces legacy C locale to C.UTF-8, C.utf8 or UTF-8 by default
- always uses C.UTF-8 on Android
- uses `surrogateescape` on stdin and stdout in the coercion
target locales
- configure option to disable locale coercion at build time
- configure option to disable C locale warning at build time
Bugfix: This test wasn't being run because it was skipping based on the
presence of Py_ENABLE_SHARED rather than its value. It is always present
on POSIX systems but defaults to 0.
Refactoring: Move the environment variables that can be ignored into a
function. Parse the list from the child process and filter out the ones
to exclude in the parent before checking that the rest is empty.
Feature: Adds always present environment variables to ignore when
running in a Gentoo sandbox so that the test can pass there.
The Windows-specific subprocess.STARTUPINFO class now accepts
keyword-only arguments to its constructor to set the various
data attributes.
Patch by Subhendu Ghosh.
Alexey Izbyshev
Serhiy Storchaka
Zachary Ware
Anders Lorentsen
Bo Bayles
Gregory P. Smith
Victor Stinner
Segev Finer
andyclegg
Oren Milman
Antoine Pitrou
Ammar Askar
Ned Deily
Ville Skyttä
Nick Coghlan
Sayan Chowdhury
Subhendu Ghosh
Xavier de Gaye
Martin Panter
Steve Dower
Raymond Hettinger