xeiaso.net
Proof of concept mechanical port of ircnet/ircd to Rust as part of a bit about C being insecure for network services
feat(p7ll): port setup_signals from ircd.c to Rust
The boot-time signal-disposition installer (ircd.c:1388, called once from
the still-C main). All callees are now Rust (dummy P7a; s_rehash/s_restart/
s_die/s_slave P7kk), so this is a clean leaf. De-static'd + body guarded
under -DPORT_IRCD_SETUP_SIGNALS_P7ll on the ircd_link.o recipe; the cref
archive keeps the de-static'd body for the L1 oracle. Config-resolved:
POSIX_SIGNALS sigaction branch, SIGWINCH defined, USE_IAUTH (s_slave +
SIGCHLD/SA_NOCLDWAIT), not __FreeBSD__, no RESTARTING_SYSTEMCALLS;
faithful cumulative sa_mask.
author
Xe Iaso
date
(Jun 7, 2026, 12:43 AM -0400)
commit
6c1e9bd5
6c1e9bd5893da4b98cab4779ead23eb18a51f2f7
parent
98df2f40
98df2f40b74ca86ea7d701f13a18adc3d7441b0d
+136
-3
+74
docs/superpowers/plans/2026-06-07-p7ll-setup_signals.md
+74
docs/superpowers/plans/2026-06-07-p7ll-setup_signals.md
···
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# P7ll — `ircd.c` `setup_signals` (signal installer)
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## Scope
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Port the static boot-time signal installer `setup_signals(void)` (ircd.c:1388) to
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`ircd-common/src/ircd.rs`. It is called once from the still-C `main()` (ircd.c:1033),
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after config read. P7kk explicitly deferred this to "its own sub-phase" because the
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installer references `dummy` (now Rust, P7a) and the four signal handlers
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`s_rehash`/`s_restart`/`s_die`/`s_slave` (now Rust, P7kk) — so all callees are finally
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Rust and the leaf is portable.
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## Config-resolved body (locked config)
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`POSIX_SIGNALS = 1` (setup.h:347) → the `sigaction` branch (not the `signal()` else).
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`SIGWINCH` defined on Linux → its `sigaddset`+`sigaction` compile. `USE_IAUTH` ON →
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the `s_slave` (SIGUSR1) arm + the `SIGCHLD`/`SA_NOCLDWAIT` arm compile. `SA_NOCLDWAIT`
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defined (glibc/musl) → `act.sa_flags = SA_NOCLDWAIT` for SIGCHLD. `RESTARTING_SYSTEMCALLS`
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undef → no `siginterrupt`. not `__FreeBSD__` → no SIGTRAP arm.
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The compiled installer, in order (cumulative `sa_mask`, `sigemptyset` called twice):
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| signal | handler | sa_flags | sa_mask (cumulative) |
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|---------|--------------------|--------------|---------------------------------|
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| SIGWINCH| SIG_IGN | 0 | {PIPE,ALRM,WINCH} |
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| SIGPIPE | SIG_IGN | 0 | {PIPE,ALRM,WINCH} |
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| SIGALRM | dummy | 0 | {PIPE,ALRM,WINCH} |
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| (sigemptyset resets mask) | | | |
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| SIGHUP | s_rehash | 0 | {HUP} |
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| SIGINT | s_restart | 0 | {HUP,INT} |
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| SIGTERM | s_die | 0 | {HUP,INT,TERM} |
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| SIGUSR1 | s_slave | 0 | {HUP,INT,TERM,USR1} |
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| SIGCHLD | SIG_IGN | SA_NOCLDWAIT | {HUP,INT,TERM,USR1,CHLD} |
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## Seam / guard
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`setup_signals` is `static` → no `cref_` oracle symbol. De-static it under
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`#ifndef PORT_IRCD_SETUP_SIGNALS_P7ll` (the P7kk/P7jj precedent), splitting the line-34
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combined static proto `static void open_debugfile(void), setup_signals(void), io_loop(void);`
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into `open_debugfile`/`io_loop` (stay static) + a guarded `setup_signals` (an `#else
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extern void setup_signals(void);` proto so the still-C `main()` keeps its declaration).
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Add `-DPORT_IRCD_SETUP_SIGNALS_P7ll` to the `ircd_link.o` recipe in `ircd-sys/build.rs`.
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## Classification → test strategy
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Boot callee (no `msgtab` entry). Reached once at boot from `main()`.
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- **L1** (`setup_signals_diff.rs`): the installer is differentially testable — it mutates
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process *signal dispositions*, not shared memory tables, and those can be
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snapshot/restored (P7kk precedent). Save all 8 dispositions; call the Rust
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`setup_signals` → query the 8 back; call `cref_setup_signals` → query the 8 back;
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restore. Assert, for every signal: `sa_flags` identical between worlds, `sa_mask`
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identical (memcmp the `sigset_t`), and the installed handler is the *correct symbol for
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that world* — SIG_IGN for SIGPIPE/SIGWINCH/SIGCHLD (identical), `dummy`/`s_rehash`/…
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in the Rust world vs `cref_dummy`/`cref_s_rehash`/… in the oracle world. Handler
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pointers differ *by design* (Rust vs cref symbol); the equality being verified is
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"right handler wired to right signal with the right mask/flags". Serialize on
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`GLOBALS_LOCK` (process-global dispositions; the P7 shared-global hazard). The
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uninitialized C `sa_restorer` doesn't leak — glibc overrides it during the syscall, so
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the queried-back struct is identical in both worlds.
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- **L2** (no new file): the still-C `main()` calls `setup_signals` on every `ircd-golden`
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boot, installing the Rust handlers — so the entire golden suite is the gate
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(`golden_registration` + the P7kk `golden_s_serv_shutdown`/`_maint` rehash/restart/die
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paths that read the installed handlers). Byte-identical = no regression.
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- **S2S**: none — formats no command-driven remote-user wire fields.
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## Checklist
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1. [ ] RED: write `ircd-testkit/tests/setup_signals_diff.rs` (fails to link: undefined `setup_signals`/`cref_setup_signals`).
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2. [ ] Edit `ircd/ircd.c`: split line-34 proto, guard `setup_signals` body under `PORT_IRCD_SETUP_SIGNALS_P7ll`.
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3. [ ] Add `-DPORT_IRCD_SETUP_SIGNALS_P7ll` to `ircd_link.o` recipe in `ircd-sys/build.rs`.
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4. [ ] GREEN: port `setup_signals` to `ircd-common/src/ircd.rs` (`crate::bsd::dummy` for SIGALRM).
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5. [ ] L1 green: `cargo test -p ircd-testkit --test setup_signals_diff`.
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6. [ ] Build (0 warnings) + golden no-regression spot-check.
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7. [ ] Commit (C edit + port + test separately per the one-test-per-commit rule); update PLAN.md + both P7 logs.
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ircd-common/src/ircd.rs
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ircd-common/src/ircd.rs
···
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}
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dorestart = 1;
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}
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/// `setup_signals(void)` (ircd.c:1388) — the boot-time signal-disposition installer,
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/// called once from the still-C `main()`. Config-resolved to the locked build:
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/// `POSIX_SIGNALS`=1 (the `sigaction` branch), `SIGWINCH` defined, `USE_IAUTH` ON
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/// (`s_slave` + the `SIGCHLD`/`SA_NOCLDWAIT` arm), `SA_NOCLDWAIT` defined, not
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/// `__FreeBSD__`, no `RESTARTING_SYSTEMCALLS`. The `sa_mask` is cumulative
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/// (`sigemptyset` is called exactly twice — once at the top, once before SIGHUP).
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#[no_mangle]
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pub unsafe extern "C" fn setup_signals() {
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let mut act: libc::sigaction = std::mem::zeroed();
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// SIG_IGN'd: SIGPIPE, SIGWINCH (mask carries PIPE/ALRM/WINCH for the IGN+dummy set).
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act.sa_sigaction = libc::SIG_IGN;
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act.sa_flags = 0;
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libc::sigemptyset(&mut act.sa_mask);
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libc::sigaddset(&mut act.sa_mask, libc::SIGPIPE);
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libc::sigaddset(&mut act.sa_mask, libc::SIGALRM);
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libc::sigaddset(&mut act.sa_mask, libc::SIGWINCH);
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libc::sigaction(libc::SIGWINCH, &act, std::ptr::null_mut());
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libc::sigaction(libc::SIGPIPE, &act, std::ptr::null_mut());
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// SIGALRM: the re-arming no-op `dummy` (bsd.rs, P7a).
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act.sa_sigaction = crate::bsd::dummy as unsafe extern "C" fn(c_int) as usize;
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libc::sigaction(libc::SIGALRM, &act, std::ptr::null_mut());
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// The four real handlers (P7kk) — mask reset, then accumulated.
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act.sa_sigaction = s_rehash as unsafe extern "C" fn(c_int) as usize;
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libc::sigemptyset(&mut act.sa_mask);
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libc::sigaddset(&mut act.sa_mask, libc::SIGHUP);
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libc::sigaction(libc::SIGHUP, &act, std::ptr::null_mut());
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act.sa_sigaction = s_restart as unsafe extern "C" fn(c_int) as usize;
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libc::sigaddset(&mut act.sa_mask, libc::SIGINT);
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libc::sigaction(libc::SIGINT, &act, std::ptr::null_mut());
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act.sa_sigaction = s_die as unsafe extern "C" fn(c_int) as usize;
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libc::sigaddset(&mut act.sa_mask, libc::SIGTERM);
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libc::sigaction(libc::SIGTERM, &act, std::ptr::null_mut());
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// USE_IAUTH: SIGUSR1 → s_slave.
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act.sa_sigaction = s_slave as unsafe extern "C" fn(c_int) as usize;
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libc::sigaddset(&mut act.sa_mask, libc::SIGUSR1);
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libc::sigaction(libc::SIGUSR1, &act, std::ptr::null_mut());
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// USE_IAUTH: reap children without zombies (SA_NOCLDWAIT defined).
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act.sa_sigaction = libc::SIG_IGN;
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act.sa_flags = libc::SA_NOCLDWAIT;
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libc::sigaddset(&mut act.sa_mask, libc::SIGCHLD);
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libc::sigaction(libc::SIGCHLD, &act, std::ptr::null_mut());
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// not __FreeBSD__ → no SIGTRAP arm; no RESTARTING_SYSTEMCALLS → no siginterrupt.
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}
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ircd-sys/build.rs
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-1
ircd-sys/build.rs
···
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.current_dir(&cbuild)
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.arg(format!("CC={cc_override}"))
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.arg(
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-
"--eval=ircd_link.o: ../ircd/ircd.c\n\t$(CC) $(S_CFLAGS) -DPORT_IRCD_TUNE_P7c -DPORT_IRCD_CALC_PREF_P7t -DPORT_IRCD_TRY_CONNECTIONS_P7gg -DPORT_IRCD_CHECK_PINGS_P7hh -DPORT_IRCD_DELAYED_KILLS_P7ii -DPORT_IRCD_SETUP_ME_P7jj -DPORT_IRCD_SIGNALS_P7kk \
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"--eval=ircd_link.o: ../ircd/ircd.c\n\t$(CC) $(S_CFLAGS) -DPORT_IRCD_TUNE_P7c -DPORT_IRCD_CALC_PREF_P7t -DPORT_IRCD_TRY_CONNECTIONS_P7gg -DPORT_IRCD_CHECK_PINGS_P7hh -DPORT_IRCD_DELAYED_KILLS_P7ii -DPORT_IRCD_SETUP_ME_P7jj -DPORT_IRCD_SIGNALS_P7kk -DPORT_IRCD_SETUP_SIGNALS_P7ll \
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-DIRCDCONF_PATH=\"\\\"$(IRCDCONF_PATH)\\\"\" \
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-DIRCDTUNE_PATH=\"\\\"$(IRCDTUNE_PATH)\\\"\" \
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-DIRCDMOTD_PATH=\"\\\"$(IRCDMOTD_PATH)\\\"\" \
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ircd/ircd.c
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ircd/ircd.c
···
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aClient me; /* That's me */
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aClient *client = &me; /* Pointer to beginning of Client list */
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static void open_debugfile(void), setup_signals(void), io_loop(void);
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static void open_debugfile(void), io_loop(void);
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/* P7ll: setup_signals de-static'd (was in the line-34 static proto group) so the
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** cref archive's prefix-rename exports cref_setup_signals for the L1 differential;
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** the body is ported to Rust (ircd-common/src/ircd.rs), guarded out of ircd_link.o
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** by -DPORT_IRCD_SETUP_SIGNALS_P7ll. */
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void setup_signals(void);
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#if defined(USE_IAUTH)
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/* P7kk: de-static'd (was `static`) so the cref archive's prefix-rename exports
···
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return;
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}
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-
static void setup_signals(void)
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#ifndef PORT_IRCD_SETUP_SIGNALS_P7ll /* ported to ircd-common/src/ircd.rs (P7ll) */
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void setup_signals(void)
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{
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#if POSIX_SIGNALS
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struct sigaction act;
···
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(void)siginterrupt(SIGALRM, 1);
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#endif
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}
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#endif /* PORT_IRCD_SETUP_SIGNALS_P7ll */
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/*
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* Called from bigger_hash_table(), s_die(), server_reboot(),