2be53ecd7b
utf-8-sig exists to tolerate BOMs that Windows tooling adds to files users edit. /proc and /sys files are generated by the Linux kernel, never BOM'd and absent on Windows, so -sig there only muddies the read/write policy. Switch every literal /proc/ and /sys/ read to utf-8 and teach the footgun read rule that string literals starting with /proc/ or /sys/ are exempt (user-edited files keep utf-8-sig).
67 lines
2.0 KiB
Python
67 lines
2.0 KiB
Python
"""SIGKILL any process left in this systemd unit's cgroup.
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Runs as ``ExecStopPost=`` after the gateway's main process has exited: the
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safety net for long-lived helpers the gateway doesn't track (``adb``, platform
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bridges) that would otherwise be orphaned in the cgroup and block
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``Restart=always``. Per-PID SIGKILLs over ``cgroup.procs`` are used instead of
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writing ``1`` to ``cgroup.kill``: the kernel has returned ``EINVAL`` on the
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cgroup-wide kill while per-PID signal delivery still works.
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"""
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from __future__ import annotations
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import contextlib
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import os
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import re
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import signal
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import sys
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from pathlib import Path
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def _own_cgroup_path() -> str | None:
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"""Return the cgroup v2 path for the calling process, or None."""
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try:
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text = Path("/proc/self/cgroup").read_text(encoding="utf-8")
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except OSError:
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return None
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match = re.search(r"^0::(.+)$", text, re.MULTILINE)
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return match.group(1).strip() if match else None
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def _read_cgroup_pids(cgroup_path: str) -> list[int]:
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try:
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raw = Path(f"/sys/fs/cgroup{cgroup_path}/cgroup.procs").read_text(encoding="utf-8")
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except OSError:
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return []
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pids: list[int] = []
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for line in raw.splitlines():
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with contextlib.suppress(ValueError):
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pids.append(int(line.strip()))
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return pids
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def reap_cgroup(cgroup_path: str | None = None) -> int:
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"""SIGKILL every PID in the cgroup other than the caller. Returns the count killed."""
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cgroup_path = _own_cgroup_path() if cgroup_path is None else cgroup_path
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if not cgroup_path:
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return 0
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killed = 0
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for pid in _read_cgroup_pids(cgroup_path):
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if pid == os.getpid():
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continue
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try:
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os.kill(pid, signal.SIGKILL) # windows-footgun: ok — Linux-only (reads /proc, /sys/fs/cgroup; runs from a systemd unit)
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killed += 1
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except (ProcessLookupError, PermissionError):
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continue
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return killed
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def main() -> int:
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reap_cgroup()
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return 0
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if __name__ == "__main__":
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sys.exit(main())
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