hermes-agent/gateway
Teknium 1cbe399149 fix(windows): os.kill(pid, 0) is NOT a no-op on Windows — route through new _pid_exists helper
On Windows, Python's ``os.kill(pid, 0)`` is NOT a no-op. CPython's
implementation (``Modules/posixmodule.c::os_kill_impl``) treats sig=0
as ``CTRL_C_EVENT`` because the two integer values collide at the C
layer, and routes it through ``GenerateConsoleCtrlEvent(0, pid)`` —
which sends a Ctrl+C to the ENTIRE console process group containing
the target PID, not just the PID itself. Any caller that wanted to
check "is PID X alive" via the classic POSIX ``os.kill(pid, 0)``
idiom was silently killing that process (and often unrelated
processes in the same console group) on Windows. Long-standing
Python Windows quirk; see bpo-14484 (open since 2012).

This manifested in Hermes as: every ``hermes gateway status``
invocation would read the gateway's PID from the PID file, call
``os.kill(pid, 0)`` via ``gateway.status.get_running_pid()`` as a
"liveness check", and instantly terminate the gateway it was trying
to report on. No shutdown log, no traceback, no atexit hook fire,
no exit-diag entry — just silent termination of the detached pythonw
process. "Bot answered one message then stopped typing" was the
characteristic end-user symptom because `os.kill(pid, 0)` fires
mid-response-send and kills the gateway between logs.

Reproduction (verified in this branch before the fix):

  $ hermes gateway start       # gateway alive, PID 37520
  $ hermes gateway status      # reports "No gateway process detected"
  $ tasklist /FI "PID eq 37520"  # INFO: No tasks are running
                                 # — gateway terminated silently

Root-cause fix is a new ``gateway.status._pid_exists(pid)`` helper:

- On Windows: Win32 ``OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION |
  SYNCHRONIZE, False, pid)`` + ``WaitForSingleObject(handle, 0)``
  via ctypes. Zero signal delivery, zero console-group side effects.
  Pins ctypes return types to avoid DWORD-vs-signed-int parse bugs
  on WAIT_TIMEOUT (0x102). Distinguishes ERROR_INVALID_PARAMETER
  (PID gone) from ERROR_ACCESS_DENIED (alive but another user).
- On POSIX: the canonical ``os.kill(pid, 0)`` idiom that actually is
  a no-op there.

Then patch every ``os.kill(pid, 0)`` liveness-check callsite to
route through ``_pid_exists`` instead. Total 14 callsites across
11 files; every single one was a latent silent-kill on Windows:

  gateway/run.py:2810      — /restart watcher (inline subprocess)
  gateway/run.py:15195     — --replace wait loop
  gateway/status.py:572    — acquire_gateway_runtime_lock stale check
  gateway/status.py:828    — get_running_pid (THE killer for status)
  gateway/platforms/whatsapp.py:111
  hermes_cli/gateway.py:228, 522, 1012  — gateway-related drain loops
  hermes_cli/kanban_db.py:2826         — _pid_alive was claiming to
                                         be cross-platform but used
                                         os.kill(pid, 0) on Windows
  hermes_cli/main.py:5792        — CLI process-kill polling
  hermes_cli/profiles.py:782     — profile stop wait loop
  plugins/google_meet/process_manager.py:74
  tools/browser_tool.py:1215, 1255  — browser daemon ownership probes
  tools/mcp_tool.py:1255, 3374     — MCP stdio orphan tracking

The watcher source in gateway/run.py:2810 is a multi-line string
that gets spawned as an inline ``python -c "..."`` subprocess, so
it can't import gateway.status. The fix for that callsite inlines
the same ctypes probe directly into the watcher source.

Tested on Windows 10 with the hermes gateway + Telegram bot:
- gateway start → alive
- 5 consecutive ``hermes gateway status`` invocations → gateway
  alive after every one, same PID reported each time (37520, 21952)
- gateway.log shows uninterrupted operation; no spurious shutdown
  entries; cron ticker and kanban dispatcher still running on
  their 60-second cadence
- bot continues answering Telegram messages throughout

Ships alongside an exit-path diagnostic wrapper in
``hermes_cli/gateway.py::run_gateway()`` that captures every way
``asyncio.run(start_gateway(...))`` can return (success, SystemExit,
KeyboardInterrupt, BaseException, atexit) with full traceback to
``logs/gateway-exit-diag.log``. This was used to prove the gateway
was being hard-killed externally (no exit event fired) and should
be kept for future Windows debugging.

Refs: https://bugs.python.org/issue14484
See also: references/windows-subprocess-sigint-storm.md in
the hermes-agent skill.
2026-05-08 12:34:27 -07:00
..
assets fix: improve telegram topic mode setup 2026-05-04 12:07:17 -07:00
builtin_hooks remove: BOOT.md built-in hook (#17093) 2026-04-28 09:50:27 -07:00
platforms fix(windows): os.kill(pid, 0) is NOT a no-op on Windows — route through new _pid_exists helper 2026-05-08 12:34:27 -07:00
__init__.py Enhance CLI with multi-platform messaging integration and configuration management 2026-02-02 19:01:51 -08:00
channel_directory.py feat: complete plugin platform parity — all 12 integration points 2026-04-29 21:56:51 -07:00
config.py feat(gateway): generic plugin hooks for env enablement + cron delivery 2026-05-07 07:15:44 -07:00
delivery.py fix(gateway): preserve case-sensitive chat IDs in DeliveryTarget.parse 2026-05-01 14:01:26 -07:00
display_config.py feat(gateway): opt-in cleanup of temporary progress bubbles (#21186) 2026-05-07 05:04:37 -07:00
hooks.py fix(plugins): register dynamically-loaded modules in sys.modules before exec 2026-04-29 23:34:35 -07:00
mirror.py fix(gateway): avoid cross-user mirror writes in per-user group sessions 2026-04-26 18:31:24 -07:00
pairing.py fix(pairing): enforce lockout on approve_code, not just generate_code (#10195) (#21325) 2026-05-07 07:18:21 -07:00
platform_registry.py feat(gateway): generic plugin hooks for env enablement + cron delivery 2026-05-07 07:15:44 -07:00
restart.py fix(gateway): address restart review feedback 2026-04-10 21:18:34 -07:00
run.py fix(windows): os.kill(pid, 0) is NOT a no-op on Windows — route through new _pid_exists helper 2026-05-08 12:34:27 -07:00
runtime_footer.py feat(gateway): opt-in runtime-metadata footer on final replies (#17026) 2026-04-28 06:50:04 -07:00
session.py refactor(gateway): simplify auto-resume + extend to crash recovery 2026-05-07 05:05:34 -07:00
session_context.py fix(cron): run due jobs in parallel to prevent serial tick starvation (#13021) 2026-04-20 11:53:07 -07:00
status.py fix(windows): os.kill(pid, 0) is NOT a no-op on Windows — route through new _pid_exists helper 2026-05-08 12:34:27 -07:00
sticker_cache.py chore: remove ~100 unused imports across 55 files (#3016) 2026-03-25 15:02:03 -07:00
stream_consumer.py chore(salvage): strip duplicated/merge-corrupted blocks from PR #17664 2026-04-29 21:56:51 -07:00
whatsapp_identity.py fix(whatsapp_identity): pin identifier regex to ASCII, clarify it's defense-in-depth 2026-04-26 20:48:31 -07:00