[jjhelmus]

Following the pattern in #155520, this adds a syscall fallback for statx.

Expose os.statx when built with Linux headers that provide the syscall number and statx struct, even if the build time libc lacks a statx wrapper.

Call the libc wrapper when available, to keep the symbol versioning and fortification checks. Fall back to the syscall if the wrapper is absent, either at build or run time. If the run time kernel lacks the syscall an OSError with errno.ENOSYS will be raised.

Detect the optional statx struct fields from the available libc or kernel headers.

os.statx is no longer exposed when the syscall is unavailable at build time, even if libc provides a wrapper. This is a rare edge case where glibc would emulate the behavior of statx at runtime.

• Issue: Resolve newer Linux os functions at runtime instead of compiling them out against old glibc #153400

[cmaloney]

I suspect this will be backportable to 3.15 once that is released (although will need a core developer to confirm)

[emmatyping]

Given 3.15 has now released, it isn't backportable anymore unfortunately

[KaiErikNiermann]

I believe this would now need the same try-catch on OSError as the other syscall fallbacks which rely on hasattr (otherwise I believe logging can crash on pre-statx-syscall kernels or the alrdy mentioned seccomp case before it has the chance to fallback to os.stat)

cpython/Lib/logging/handlers.py

Lines 288 to 290 in 5607381

	if hasattr(os, 'statx'):
	statx_result = os.statx(filename,
	os.STATX_BTIME|os.STATX_CTIME|os.STATX_MTIME)

e.g.

cpython/Lib/asyncio/unix_events.py

Lines 1025 to 1033 in 5607381

	if not hasattr(os, 'pidfd_open'):
	return False
	try:
	pid = os.getpid()
	os.close(os.pidfd_open(pid, 0))
	except OSError:
	# blocked by security policy like SECCOMP
	return False
	return True

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #35285605 | 📁 Comparing 943aa85 against main (80040b6)

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3 files changed

± library/ast.html
± library/os.html
± whatsnew/changelog.html

[python-cla-bot]

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