posix, fcntl, io: re-issue interrupted syscalls instead of reporting EINTR

[youknowone]

wrap_oserror(..., eintr_retry=True) runs the pending Python signal handlers and re-issues the call; the loop ends only when a handler raises. These sites reported the interruption directly.

interp_posix.py — open, stat/fstat by descriptor, fchdir, fsync, fdatasync, waitpid, mkfifo, mknod, fstatvfs, chmod, lchmod, fchmod, chown, lchown, fchown, sched_yield, sched_get_priority_max, sched_get_priority_min, sched_rr_get_interval, sched_getscheduler, sched_setscheduler, sched_getparam, sched_setparam. posix.wait is posix.waitpid(-1, 0) and takes that call's loop.

chmod reads an ENOTSUP/EOPNOTSUPP refusal of follow_symlinks=False as the modifier being unavailable rather than as an OS error, and reads it ahead of the retry (interp_posix.py:1247-1251).

interp_fcntl.py — fcntl, flock and lockf take their descriptor through space.c_filedescriptor_w and retry through _raise_error_maybe. ioctl takes its descriptor the same way; it reports through _raise_error_always and does not retry.

interp_fileio.py:135-147 _open_fd — the same loop around the open in open_raw_file.

Verification (arm64 linux container, dynasm)

• test_eintr: 25 tests, OK (skipped=7). Before this change the suite died on its first test.
• test_fcntl: 8 errors → 3. The remaining three are all fcntl.fcntl(fd, cmd, bytes), the buffer form the module documents as unimplemented; they fail identically without this change.

Not from this change

test.test_io deadlocks on linux at PyBufferedRandomTest.test_writes_and_reads — W_Lock::acquire on a _pyio threading.Lock, zero CPU, 8/8 runs. A control binary built with these three files reverted deadlocks 8/8 as well, and PYRE_NO_JIT=1 clears it (0/2), so it is a pre-existing JIT-only defect on main. It goes unnoticed because baseline.json records test.test_io as IMPORTERROR, and a module recorded non-PASS is never executed by the runner.

— authored by Claude

Summary by CodeRabbit

• Bug Fixes
  • Improved reliability of file, descriptor, scheduling, locking, and synchronization operations when interrupted by signals.
  • File-opening and POSIX operations now retry safely after temporary interruptions while preserving existing error behavior.
  • File-control operations now support file objects and other supported descriptor wrappers, not only integer descriptors.
  • Improved validation and error reporting for locking and control operations.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 0efe4186-5c74-4256-b80d-8c547460a744

📥 Commits

Reviewing files that changed from the base of the PR and between bc56455 and 963f3bf.

📒 Files selected for processing (3)

• pyre/pyre-interpreter/src/builtins.rs
• pyre/pyre-interpreter/src/module/fcntl/interp_fcntl.rs
• pyre/pyre-interpreter/src/module/posix/interp_posix.rs

---

Walkthrough

The interpreter now retries selected OS-level EINTR failures across file opening, fcntl, locking, scheduling, waiting, synchronization, filesystem creation, permission, and ownership operations. Descriptor wrappers are accepted by updated fcntl functions.

Changes

System-call interruption handling

Layer / File(s)	Summary
File opening retries pyre/pyre-interpreter/src/builtins.rs, pyre/pyre-interpreter/src/module/posix/interp_posix.rs	File-opening calls retry OS-level EINTR errors and preserve filename-aware error conversion.
Descriptor and locking operations pyre/pyre-interpreter/src/module/fcntl/interp_fcntl.rs	fcntl, flock, and lockf resolve descriptors with c_filedescriptor_w and retry selected interrupted operations. ioctl preserves interruption as an error.
Scheduling, waiting, and synchronization retries pyre/pyre-interpreter/src/module/posix/interp_posix.rs	Scheduling, wait, synchronization, metadata, and node-creation calls retry interrupted system calls.
Permission and ownership updates pyre/pyre-interpreter/src/module/posix/interp_posix.rs	chmod and chown variants retry interrupted updates while preserving existing unsupported and direct-error cases.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: 🟡 Moderate · up to 963f3

The change retries interrupted system calls, but sandbox-backed open paths still return EINTR as an error without retrying, leaving callers with inconsistent behavior and avoidable interruption failures. The PR is not merge-ready until those paths are updated or the exception is explicitly accepted.

Sequence Diagram(s)

sequenceDiagram
  participant PythonAPI
  participant InterpreterWrapper
  participant OperatingSystem
  PythonAPI->>InterpreterWrapper: Invoke POSIX or fcntl operation
  InterpreterWrapper->>OperatingSystem: Execute system call
  OperatingSystem-->>InterpreterWrapper: EINTR or operation result
  InterpreterWrapper->>OperatingSystem: Retry interrupted operation
  OperatingSystem-->>InterpreterWrapper: Final result or OS error
  InterpreterWrapper-->>PythonAPI: Return value or converted exception

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Possibly related PRs

• youknowone/pyre#1078: Both modify descriptor-aware POSIX wrappers and lockf behavior.
• youknowone/pyre#1081: Both extend shared filesystem and POSIX syscall wrappers.
• youknowone/pyre#1239: Both modify shared file and POSIX wrappers for EINTR handling.

Poem

A rabbit watched the syscall hop,
Then caught EINTR before the stop.
It tried once more through every gate,
While locks and files resumed their state.
“No startled pause shall block the way!”
Said Bunny, nibbling code today.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely summarizes the main change: retrying interrupted POSIX, fcntl, and I/O system calls.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[github-actions]

🤖 Codex parity review

Static analysis of this diff vs the local RPython/PyPy sources (commit 963f3bf).
Updated: 2026-08-15T19:07:08.227Z

Files in the reviewed diff

pyre/pyre-interpreter/src/builtins.rs
pyre/pyre-interpreter/src/module/fcntl/interp_fcntl.rs
pyre/pyre-interpreter/src/module/posix/interp_posix.rs

1. Regressions to PyPy parity introduced by this patch

None.

2. Other mismatches introduced by this patch

• pyre/pyre-interpreter/src/module/posix/interp_posix.rs:5683 ↔ pypy/module/posix/interp_posix.py:3062 — Pyre retries sched_rr_get_interval() after a handled EINTR; PyPy calls wrap_oserror(..., eintr_retry=True) outside a loop, so it returns None after the handler rather than reissuing the syscall.

• pyre/pyre-interpreter/src/module/posix/interp_posix.rs:5719 ↔ pypy/module/posix/interp_posix.py:3074 — Pyre loops and retries sched_getscheduler() on handled EINTR; PyPy has no enclosing retry loop and falls through with None.

• pyre/pyre-interpreter/src/module/posix/interp_posix.rs:5750 ↔ pypy/module/posix/interp_posix.py:3104 — Pyre loops and retries sched_getparam() on handled EINTR; PyPy does not retry.

• pyre/pyre-interpreter/src/module/posix/interp_posix.rs:5792 ↔ pypy/module/posix/interp_posix.py:3086 — Pyre loops and retries sched_setscheduler() on handled EINTR; PyPy does not retry.

• pyre/pyre-interpreter/src/module/posix/interp_posix.rs:5825 ↔ pypy/module/posix/interp_posix.py:3119 — Pyre loops and retries sched_setparam() on handled EINTR; PyPy does not retry.

3. Pre-existing mismatches (already present before this patch)

• pyre/pyre-interpreter/src/module/fcntl/interp_fcntl.rs:24 ↔ pypy/module/fcntl/interp_fcntl.py:117 — fcntl.fcntl() rejects a bytes buffer argument and implements only the integer form; PyPy passes the buffer to fcntl_str() and returns the resulting bytes.

• pyre/pyre-interpreter/src/module/fcntl/interp_fcntl.rs:75 ↔ pypy/module/fcntl/interp_fcntl.py:214 — fcntl.ioctl() accepts only two or three integer arguments. PyPy supports the fourth mutate_flag argument and immutable/mutable buffer forms.

• pyre/pyre-interpreter/src/module/fcntl/interp_fcntl.rs:127 ↔ pypy/module/fcntl/interp_fcntl.py:142 — flock() checks only for fewer than two arguments and ignores extras; PyPy’s two-argument gateway rejects them.

• pyre/pyre-interpreter/src/module/posix/interp_posix.rs:5510 ↔ pypy/module/posix/interp_posix.py:3018 — Pyre returns None from sched_yield(); PyPy returns the syscall’s integer result.

• pyre/pyre-interpreter/src/module/posix/interp_posix.rs:5801 ↔ pypy/module/posix/interp_posix.py:3086 — Pyre returns None from successful sched_setscheduler(); PyPy returns its integer syscall result.

• pyre/pyre-interpreter/src/module/posix/interp_posix.rs:5834 ↔ pypy/module/posix/interp_posix.py:3119 — Pyre returns None from successful sched_setparam(); PyPy returns its integer syscall result.

• pyre/pyre-interpreter/src/module/posix/interp_posix.rs:7670 ↔ pypy/module/posix/interp_posix.py:2501 — Pyre always routes pathname chown through fchownat, including the unmodified AT_FDCWD/follow-symlinks case; PyPy selects os.chown for that case and os.lchown for lchown (pypy/module/posix/interp_posix.py:2515).

4. Structural adaptations

None.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Match PyPy's one-shot scheduler control flow

When sched_rr_get_interval is interrupted and the Python signal handler returns normally, pypy/module/posix/interp_posix.py:3065-3070 has only one try/except: wrap_oserror(..., eintr_retry=True) returns and the function falls through to None. This added loop instead reissues the syscall and returns a float; the same divergence occurs in the adjacent sched_getscheduler, sched_getparam, sched_setscheduler, and sched_setparam ports. Preserve PyPy's control-flow shape unless each site is recorded and supported as a CPython 3.14 spec deviation.

AGENTS.md reference: AGENTS.md:L249-L254

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