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1. // tests/browser/ports.mjs — the two port questions the CDP driver has to ask,
2. // and the reasons they are asked this way. They lived in the hl:web browser
3. // tier's `fixtures.mjs` until that tier moved to `archive/hlweb-v1/`
4. // (2026-09-10); the driver survives it, so its dependencies do too.
5. //
6. // Every process a caller starts is its own to kill BY PID — never `pkill -f`,
7. // which on this machine matches sibling sessions' runners.
8. //
9. // `portOpen` (a plain connect) is NOT here: the driver keeps its own, because
10. // "something answers" is a different question from "this port is free", and
11. // only the second one needs the reasons written down.
13. import { createServer as netServer } from 'node:net';
14. import { execFileSync } from 'node:child_process';
16. /**
17. * A BIND IS THE QUESTION, SO A BIND IS THE TEST (mission 285). A listener on a
18. * LAN address is invisible to a loopback connect and still takes the port from
19. * a server that binds 0.0.0.0 — which is how a browser-tier red once looked
20. * like a hung server: the app's own log said `bind() failed on port N` while
21. * every "is it open?" probe said no.
22. *
23. * Nothing is left behind: a listening socket with no accepted connections
24. * leaves no TIME_WAIT when it closes.
25. */
26. export function portBindable(port) {
27. return bindProbe(port).then((r) => r.ok);
28. }
30. /**
31. * The same probe with the kernel's own word for WHY. `EADDRINUSE` is a
32. * collision and is what this file is about; anything else (EACCES, EMFILE …)
33. * is a different problem and must not be reported as one, because an error
34. * that names the wrong cause costs the next reader a whole night.
35. */
36. function bindProbe(port) {
37. return new Promise((res) => {
38. const s = netServer();
39. s.once('error', (e) => res({ ok: false, code: (e && e.code) || String(e) }));
40. s.listen(port, '0.0.0.0', () => s.close(() => res({ ok: true, code: null })));
41. });
42. }
44. /**
45. * Every socket on `port`, in any state, with its owner — `ss -tanp`. LISTEN is
46. * the state that actually blocks a bind (measured: TIME_WAIT and ESTABLISHED do
47. * not, on loopback or on the LAN address), so a report showing only listeners
48. * and finding none says "nothing", which is the least useful thing a diagnostic
49. * can say. Show the whole port.
50. */
51. export function whoHolds(port) {
52. try {
53. const out = execFileSync('ss', ['-tanp'], { encoding: 'utf-8' });
54. const hits = out.split('\n').filter((l) => new RegExp(`:${port}(\\s|$)`).test(l));
55. return hits.length
56. ? hits.map((l) => l.trim().replace(/\s+/g, ' ')).join('\n ')
57. : '(no socket on that port at all by the time `ss` ran — the holder let go between the failed bind and this line)';
58. } catch { return '(`ss` is not runnable here)'; }
59. }