shoney.arickathil
6e997759e5
- five stories status: done; 00-story records the one-run landing - spec History: three implementation amendments (Signal record not scalar, caller-owned stdio fds, handler-latch instead of signalfd) - board NEXT PLAN entry with measured findings (zero transport code added; the tty-across-the-socket handover proven; the double-raw refusal restoring the terminal — the "bug" that was the design working); section rows flipped; graph nodes green - CODE-LOGIC.md: the runtime-v2 section - full belt quoted on the board: suites 0 fail both flavors (test_proc 193/0, test_term 60/0), woc 557/0, subprocess 12/0, site 23/0 Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> (cherry picked from commit bc1b4f070693eb755ad6a9fd0c853fb3e2bda347)
55 lines
2.4 KiB
Markdown
55 lines
2.4 KiB
Markdown
---
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track: runtime-v2
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iteration: "3"
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status: done
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readiness: ready
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---
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# runtime-v2 3 — signals as events: SIGWINCH into a mailbox
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> Part of [Story — runtime-v2: the runtime beyond sockets](00-story.md).
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> The seam iteration
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> [42](../language-runtime-database/42-bounded-subprocess.md)
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> deliberately deferred "to its real consumer" — this is that consumer
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> arriving. A terminal application's resize IS a signal (SIGWINCH), and
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> nothing today can turn a signal into anything a program observes
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> except the SIGTERM/SIGINT stop latch.
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>
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> **The problem.** Signals are process-global, delivered on an arbitrary
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> thread, and allowed to do almost nothing — the exact opposite of a
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> shard-owned mailbox message. The runtime already crossed this bridge
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> once: the stop flag is a signal made safe by latching. This iteration
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> generalizes that shape without handing user code a signal handler.
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## Info — the forks, settled (brainstorm 2026-09-01; spec:
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[`2026-09-01-runtime-v2-design.md`](../../superpowers/specs/2026-09-01-runtime-v2-design.md))
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1. **`signal.on(sig, addr)`** — a standing subscription delivering the
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SIGNAL NUMBER as a scalar message. No moved-message ownership rules:
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scalars copy, so a repeating SIGWINCH needs no per-delivery payload.
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2. **signalfd on shard 0's plane** — one more registered fd with a
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sentinel `user_data` (the wake-eventfd precedent); reads drain
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`signalfd_siginfo` records and fan out ordinary sends.
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3. **Offerable set: SIGWINCH, SIGCHLD, SIGHUP, SIGUSR1, SIGUSR2.**
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SIGTERM/SIGINT registration is refused by name — the stop latch
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stays the engine's, iteration 40 is load-bearing.
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4. **Coalescing disclosed, not sequenced** — what SIGWINCH consumers
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expect anyway.
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Also settled: this iteration is STANDALONE — the old edge from PTY was
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only the resize pairing; signalfd needs nothing from iteration 2.
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## Acceptance sketch
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- Resize the controlling terminal of a test child: the registered actor
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receives the message; the grid-owning code calls
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[2](02-pty.md)'s resize onward — the wmux wiring, proven in miniature.
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- SIGCHLD registration does not disturb 42's pidfd machinery (they
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coexist; the pidfd stays the reap path).
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- SIGTERM still stops the engine with the full drain — the iteration 40
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battery unchanged.
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## Consumers
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wmux 1 (SIGWINCH fan-out to panes). Everything else can wait — this
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iteration exists exactly once a real consumer does, per 42's deferral.
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