TLA Line data Source code
1 : //
2 : // Copyright (c) 2026 Steve Gerbino
3 : //
4 : // Distributed under the Boost Software License, Version 1.0. (See accompanying
5 : // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 : //
7 : // Official repository: https://github.com/cppalliance/corosio
8 : //
9 :
10 : #ifndef BOOST_COROSIO_NATIVE_DETAIL_POSIX_POSIX_SIGNAL_SERVICE_HPP
11 : #define BOOST_COROSIO_NATIVE_DETAIL_POSIX_POSIX_SIGNAL_SERVICE_HPP
12 :
13 : #include <boost/corosio/detail/platform.hpp>
14 :
15 : #if BOOST_COROSIO_POSIX
16 :
17 : #include <boost/corosio/native/detail/posix/posix_signal.hpp>
18 :
19 : #include <boost/corosio/detail/config.hpp>
20 : #include <boost/capy/ex/execution_context.hpp>
21 : #include <boost/corosio/detail/scheduler.hpp>
22 : #include <boost/capy/error.hpp>
23 :
24 : #include <mutex>
25 :
26 : #include <signal.h>
27 :
28 : /*
29 : POSIX Signal Service
30 : ====================
31 :
32 : Concrete signal service implementation for POSIX backends. Manages signal
33 : registrations via sigaction() and dispatches completions through the
34 : scheduler. One instance per execution_context, created by
35 : get_signal_service().
36 :
37 : See the block comment further down for the full architecture overview.
38 : */
39 :
40 : /*
41 : POSIX Signal Implementation
42 : ===========================
43 :
44 : This file implements signal handling for POSIX systems using sigaction().
45 : The implementation supports signal flags (SA_RESTART, etc.) and integrates
46 : with any POSIX-compatible scheduler via the abstract scheduler interface.
47 :
48 : Architecture Overview
49 : ---------------------
50 :
51 : Three layers manage signal registrations:
52 :
53 : 1. signal_state (global singleton)
54 : - Tracks the global service list and per-signal registration counts
55 : - Stores the flags used for first registration of each signal (for
56 : conflict detection when multiple signal_sets register same signal)
57 : - Owns the mutex that protects signal handler installation/removal
58 :
59 : 2. posix_signal_service (one per execution_context)
60 : - Maintains registrations_[] table indexed by signal number
61 : - Each slot is a doubly-linked list of signal_registrations for that signal
62 : - Also maintains impl_list_ of all posix_signal objects it owns
63 :
64 : 3. posix_signal (one per signal_set)
65 : - Owns a singly-linked list (sorted by signal number) of signal_registrations
66 : - Contains the pending_op_ used for wait operations
67 :
68 : Signal Delivery Flow
69 : --------------------
70 :
71 : 1. Signal arrives -> corosio_posix_signal_handler() (must be async-signal-safe)
72 : -> deliver_signal()
73 :
74 : 2. deliver_signal() iterates all posix_signal_service services:
75 : - If a signal_set is waiting (impl->waiting_ == true), post the signal_op
76 : to the scheduler for immediate completion
77 : - Otherwise, increment reg->undelivered to queue the signal
78 :
79 : 3. When wait() is called via start_wait():
80 : - First check for queued signals (undelivered > 0); if found, post
81 : immediate completion without blocking
82 : - Otherwise, set waiting_ = true and call work_started() to keep
83 : the io_context alive
84 :
85 : Locking Protocol
86 : ----------------
87 :
88 : Two mutex levels exist (MUST acquire in this order to avoid deadlock):
89 : 1. signal_state::mutex - protects handler registration and service list
90 : 2. posix_signal_service::mutex_ - protects per-service registration tables
91 :
92 : Async-Signal-Safety Limitation
93 : ------------------------------
94 :
95 : IMPORTANT: deliver_signal() is called from signal handler context and
96 : acquires mutexes. This is NOT strictly async-signal-safe per POSIX.
97 : The limitation:
98 : - If a signal arrives while another thread holds state->mutex or
99 : service->mutex_, and that same thread receives the signal, a
100 : deadlock can occur (self-deadlock on non-recursive mutex).
101 :
102 : This design trades strict async-signal-safety for implementation simplicity.
103 : In practice, deadlocks are rare because:
104 : - Mutexes are held only briefly during registration changes
105 : - Most programs don't modify signal sets while signals are expected
106 : - The window for signal arrival during mutex hold is small
107 :
108 : A fully async-signal-safe implementation would require lock-free data
109 : structures and atomic operations throughout, significantly increasing
110 : complexity.
111 :
112 : Flag Handling
113 : -------------
114 :
115 : - Flags are abstract values in the public API (signal_set::flags_t)
116 : - flags_supported() validates that requested flags are available on
117 : this platform; returns false if SA_NOCLDWAIT is unavailable and
118 : no_child_wait is requested
119 : - to_sigaction_flags() maps validated flags to actual SA_* constants
120 : - First registration of a signal establishes the flags; subsequent
121 : registrations must be compatible (same flags or dont_care)
122 : - Requesting unavailable flags returns operation_not_supported
123 :
124 : Work Tracking
125 : -------------
126 :
127 : When waiting for a signal:
128 : - start_wait() calls sched_->work_started() to prevent io_context::run()
129 : from returning while we wait
130 : - signal_op::svc is set to point to the service
131 : - signal_op::operator()() calls work_finished() after resuming the coroutine
132 :
133 : If a signal was already queued (undelivered > 0), no work tracking is needed
134 : because completion is posted immediately.
135 : */
136 :
137 : namespace boost::corosio {
138 :
139 : namespace detail {
140 :
141 : /** Signal service for POSIX backends.
142 :
143 : Manages signal registrations via sigaction() and dispatches signal
144 : completions through the scheduler. One instance per execution_context.
145 : */
146 : class BOOST_COROSIO_DECL posix_signal_service final
147 : : public capy::execution_context::service
148 : , public io_object::io_service
149 : {
150 : public:
151 : using key_type = posix_signal_service;
152 :
153 : posix_signal_service(capy::execution_context& ctx, scheduler& sched);
154 : ~posix_signal_service() override;
155 :
156 : posix_signal_service(posix_signal_service const&) = delete;
157 : posix_signal_service& operator=(posix_signal_service const&) = delete;
158 :
159 : io_object::implementation* construct() override;
160 :
161 HIT 88 : void destroy(io_object::implementation* p) override
162 : {
163 88 : auto& impl = static_cast<posix_signal&>(*p);
164 88 : [[maybe_unused]] auto n = impl.clear();
165 88 : impl.cancel();
166 88 : destroy_impl(impl);
167 88 : }
168 :
169 : void shutdown() override;
170 :
171 : void destroy_impl(posix_signal& impl);
172 :
173 : std::error_code add_signal(
174 : posix_signal& impl, int signal_number, signal_set::flags_t flags);
175 :
176 : std::error_code remove_signal(posix_signal& impl, int signal_number);
177 :
178 : std::error_code clear_signals(posix_signal& impl);
179 :
180 : void cancel_wait(posix_signal& impl);
181 : void start_wait(posix_signal& impl, signal_op* op);
182 :
183 : static void deliver_signal(int signal_number);
184 :
185 : void work_started() noexcept;
186 : void work_finished() noexcept;
187 : void post(signal_op* op);
188 :
189 : private:
190 : static void add_service(posix_signal_service* service);
191 : static void remove_service(posix_signal_service* service);
192 :
193 : scheduler* sched_;
194 : std::mutex mutex_;
195 : intrusive_list<posix_signal> impl_list_;
196 :
197 : // Per-signal registration table
198 : signal_registration* registrations_[max_signal_number];
199 :
200 : // Registration counts for each signal
201 : std::size_t registration_count_[max_signal_number];
202 :
203 : // Linked list of all posix_signal_service services for signal delivery
204 : posix_signal_service* next_ = nullptr;
205 : posix_signal_service* prev_ = nullptr;
206 : };
207 :
208 : /** Get or create the signal service for the given context.
209 :
210 : This function is called by the concrete scheduler during initialization
211 : to create the signal service with a reference to itself.
212 :
213 : @param ctx Reference to the owning execution_context.
214 : @param sched Reference to the scheduler for posting completions.
215 : @return Reference to the signal service.
216 : */
217 : posix_signal_service&
218 : get_signal_service(capy::execution_context& ctx, scheduler& sched);
219 :
220 : } // namespace detail
221 :
222 : } // namespace boost::corosio
223 :
224 : // ---------------------------------------------------------------------------
225 : // Inline implementation
226 : // ---------------------------------------------------------------------------
227 :
228 : namespace boost::corosio {
229 :
230 : namespace detail {
231 :
232 : namespace posix_signal_detail {
233 :
234 : struct signal_state
235 : {
236 : std::mutex mutex;
237 : posix_signal_service* service_list = nullptr;
238 : std::size_t registration_count[max_signal_number] = {};
239 : signal_set::flags_t registered_flags[max_signal_number] = {};
240 : };
241 :
242 : BOOST_COROSIO_DECL signal_state* get_signal_state();
243 :
244 : // Check if requested flags are supported on this platform.
245 : // Returns true if all flags are supported, false otherwise.
246 : inline bool
247 94 : flags_supported([[maybe_unused]] signal_set::flags_t flags)
248 : {
249 : #ifndef SA_NOCLDWAIT
250 : if (flags & signal_set::no_child_wait)
251 : return false;
252 : #endif
253 94 : return true;
254 : }
255 :
256 : // Map abstract flags to sigaction() flags.
257 : // Caller must ensure flags_supported() returns true first.
258 : inline int
259 76 : to_sigaction_flags(signal_set::flags_t flags)
260 : {
261 76 : int sa_flags = 0;
262 76 : if (flags & signal_set::restart)
263 18 : sa_flags |= SA_RESTART;
264 76 : if (flags & signal_set::no_child_stop)
265 MIS 0 : sa_flags |= SA_NOCLDSTOP;
266 : #ifdef SA_NOCLDWAIT
267 HIT 76 : if (flags & signal_set::no_child_wait)
268 MIS 0 : sa_flags |= SA_NOCLDWAIT;
269 : #endif
270 HIT 76 : if (flags & signal_set::no_defer)
271 2 : sa_flags |= SA_NODEFER;
272 76 : if (flags & signal_set::reset_handler)
273 MIS 0 : sa_flags |= SA_RESETHAND;
274 HIT 76 : return sa_flags;
275 : }
276 :
277 : // Check if two flag values are compatible
278 : inline bool
279 18 : flags_compatible(signal_set::flags_t existing, signal_set::flags_t requested)
280 : {
281 : // dont_care is always compatible
282 34 : if ((existing & signal_set::dont_care) ||
283 16 : (requested & signal_set::dont_care))
284 6 : return true;
285 :
286 : // Mask out dont_care bit for comparison
287 12 : constexpr auto mask = ~signal_set::dont_care;
288 12 : return (existing & mask) == (requested & mask);
289 : }
290 :
291 : // C signal handler - must be async-signal-safe
292 : inline void
293 20 : corosio_posix_signal_handler(int signal_number)
294 : {
295 20 : posix_signal_service::deliver_signal(signal_number);
296 : // Note: With sigaction(), the handler persists automatically
297 : // (unlike some signal() implementations that reset to SIG_DFL)
298 20 : }
299 :
300 : } // namespace posix_signal_detail
301 :
302 : // signal_op implementation
303 :
304 : inline void
305 22 : signal_op::operator()()
306 : {
307 22 : if (ec_out)
308 22 : *ec_out = {};
309 22 : if (signal_out)
310 22 : *signal_out = signal_number;
311 :
312 : // Capture svc before resuming (coro may destroy us)
313 22 : auto* service = svc;
314 22 : svc = nullptr;
315 :
316 22 : d.post(h);
317 :
318 : // Balance the work_started() from start_wait
319 22 : if (service)
320 12 : service->work_finished();
321 22 : }
322 :
323 : inline void
324 MIS 0 : signal_op::destroy()
325 : {
326 : // No-op: signal_op is embedded in posix_signal
327 0 : }
328 :
329 : // posix_signal implementation
330 :
331 HIT 88 : inline posix_signal::posix_signal(posix_signal_service& svc) noexcept
332 88 : : svc_(svc)
333 : {
334 88 : }
335 :
336 : inline std::coroutine_handle<>
337 26 : posix_signal::wait(
338 : std::coroutine_handle<> h,
339 : capy::executor_ref d,
340 : std::stop_token token,
341 : std::error_code* ec,
342 : int* signal_out)
343 : {
344 26 : pending_op_.h = h;
345 26 : pending_op_.d = d;
346 26 : pending_op_.ec_out = ec;
347 26 : pending_op_.signal_out = signal_out;
348 26 : pending_op_.signal_number = 0;
349 :
350 26 : if (token.stop_requested())
351 : {
352 MIS 0 : if (ec)
353 0 : *ec = make_error_code(capy::error::canceled);
354 0 : if (signal_out)
355 0 : *signal_out = 0;
356 0 : d.post(h);
357 : // completion is always posted to scheduler queue, never inline.
358 0 : return std::noop_coroutine();
359 : }
360 :
361 HIT 26 : svc_.start_wait(*this, &pending_op_);
362 : // completion is always posted to scheduler queue, never inline.
363 26 : return std::noop_coroutine();
364 : }
365 :
366 : inline std::error_code
367 96 : posix_signal::add(int signal_number, signal_set::flags_t flags)
368 : {
369 96 : return svc_.add_signal(*this, signal_number, flags);
370 : }
371 :
372 : inline std::error_code
373 4 : posix_signal::remove(int signal_number)
374 : {
375 4 : return svc_.remove_signal(*this, signal_number);
376 : }
377 :
378 : inline std::error_code
379 92 : posix_signal::clear()
380 : {
381 92 : return svc_.clear_signals(*this);
382 : }
383 :
384 : inline void
385 100 : posix_signal::cancel()
386 : {
387 100 : svc_.cancel_wait(*this);
388 100 : }
389 :
390 : // posix_signal_service implementation
391 :
392 340 : inline posix_signal_service::posix_signal_service(
393 340 : capy::execution_context&, scheduler& sched)
394 340 : : sched_(&sched)
395 : {
396 22100 : for (int i = 0; i < max_signal_number; ++i)
397 : {
398 21760 : registrations_[i] = nullptr;
399 21760 : registration_count_[i] = 0;
400 : }
401 340 : add_service(this);
402 340 : }
403 :
404 680 : inline posix_signal_service::~posix_signal_service()
405 : {
406 340 : remove_service(this);
407 680 : }
408 :
409 : inline void
410 340 : posix_signal_service::shutdown()
411 : {
412 340 : std::lock_guard lock(mutex_);
413 :
414 340 : for (auto* impl = impl_list_.pop_front(); impl != nullptr;
415 MIS 0 : impl = impl_list_.pop_front())
416 : {
417 0 : while (auto* reg = impl->signals_)
418 : {
419 0 : impl->signals_ = reg->next_in_set;
420 0 : delete reg;
421 0 : }
422 0 : delete impl;
423 : }
424 HIT 340 : }
425 :
426 : inline io_object::implementation*
427 88 : posix_signal_service::construct()
428 : {
429 88 : auto* impl = new posix_signal(*this);
430 :
431 : {
432 88 : std::lock_guard lock(mutex_);
433 88 : impl_list_.push_back(impl);
434 88 : }
435 :
436 88 : return impl;
437 : }
438 :
439 : inline void
440 88 : posix_signal_service::destroy_impl(posix_signal& impl)
441 : {
442 : {
443 88 : std::lock_guard lock(mutex_);
444 88 : impl_list_.remove(&impl);
445 88 : }
446 :
447 88 : delete &impl;
448 88 : }
449 :
450 : inline std::error_code
451 96 : posix_signal_service::add_signal(
452 : posix_signal& impl, int signal_number, signal_set::flags_t flags)
453 : {
454 96 : if (signal_number < 0 || signal_number >= max_signal_number)
455 2 : return make_error_code(std::errc::invalid_argument);
456 :
457 : // Validate that requested flags are supported on this platform
458 : // (e.g., SA_NOCLDWAIT may not be available on all POSIX systems)
459 94 : if (!posix_signal_detail::flags_supported(flags))
460 MIS 0 : return make_error_code(std::errc::operation_not_supported);
461 :
462 : posix_signal_detail::signal_state* state =
463 HIT 94 : posix_signal_detail::get_signal_state();
464 94 : std::lock_guard state_lock(state->mutex);
465 94 : std::lock_guard lock(mutex_);
466 :
467 : // Find insertion point (list is sorted by signal number)
468 94 : signal_registration** insertion_point = &impl.signals_;
469 94 : signal_registration* reg = impl.signals_;
470 104 : while (reg && reg->signal_number < signal_number)
471 : {
472 10 : insertion_point = ®->next_in_set;
473 10 : reg = reg->next_in_set;
474 : }
475 :
476 : // Already registered in this set - check flag compatibility
477 : // (same signal_set adding same signal twice with different flags)
478 94 : if (reg && reg->signal_number == signal_number)
479 : {
480 10 : if (!posix_signal_detail::flags_compatible(reg->flags, flags))
481 2 : return make_error_code(std::errc::invalid_argument);
482 8 : return {};
483 : }
484 :
485 : // Check flag compatibility with global registration
486 : // (different signal_set already registered this signal with different flags)
487 84 : if (state->registration_count[signal_number] > 0)
488 : {
489 8 : if (!posix_signal_detail::flags_compatible(
490 : state->registered_flags[signal_number], flags))
491 2 : return make_error_code(std::errc::invalid_argument);
492 : }
493 :
494 82 : auto* new_reg = new signal_registration;
495 82 : new_reg->signal_number = signal_number;
496 82 : new_reg->flags = flags;
497 82 : new_reg->owner = &impl;
498 82 : new_reg->undelivered = 0;
499 :
500 : // Install signal handler on first global registration
501 82 : if (state->registration_count[signal_number] == 0)
502 : {
503 76 : struct sigaction sa = {};
504 76 : sa.sa_handler = posix_signal_detail::corosio_posix_signal_handler;
505 76 : sigemptyset(&sa.sa_mask);
506 76 : sa.sa_flags = posix_signal_detail::to_sigaction_flags(flags);
507 :
508 76 : if (::sigaction(signal_number, &sa, nullptr) < 0)
509 : {
510 MIS 0 : delete new_reg;
511 0 : return make_error_code(std::errc::invalid_argument);
512 : }
513 :
514 : // Store the flags used for first registration
515 HIT 76 : state->registered_flags[signal_number] = flags;
516 : }
517 :
518 82 : new_reg->next_in_set = reg;
519 82 : *insertion_point = new_reg;
520 :
521 82 : new_reg->next_in_table = registrations_[signal_number];
522 82 : new_reg->prev_in_table = nullptr;
523 82 : if (registrations_[signal_number])
524 6 : registrations_[signal_number]->prev_in_table = new_reg;
525 82 : registrations_[signal_number] = new_reg;
526 :
527 82 : ++state->registration_count[signal_number];
528 82 : ++registration_count_[signal_number];
529 :
530 82 : return {};
531 94 : }
532 :
533 : inline std::error_code
534 4 : posix_signal_service::remove_signal(posix_signal& impl, int signal_number)
535 : {
536 4 : if (signal_number < 0 || signal_number >= max_signal_number)
537 MIS 0 : return make_error_code(std::errc::invalid_argument);
538 :
539 : posix_signal_detail::signal_state* state =
540 HIT 4 : posix_signal_detail::get_signal_state();
541 4 : std::lock_guard state_lock(state->mutex);
542 4 : std::lock_guard lock(mutex_);
543 :
544 4 : signal_registration** deletion_point = &impl.signals_;
545 4 : signal_registration* reg = impl.signals_;
546 4 : while (reg && reg->signal_number < signal_number)
547 : {
548 MIS 0 : deletion_point = ®->next_in_set;
549 0 : reg = reg->next_in_set;
550 : }
551 :
552 HIT 4 : if (!reg || reg->signal_number != signal_number)
553 2 : return {};
554 :
555 : // Restore default handler on last global unregistration
556 2 : if (state->registration_count[signal_number] == 1)
557 : {
558 2 : struct sigaction sa = {};
559 2 : sa.sa_handler = SIG_DFL;
560 2 : sigemptyset(&sa.sa_mask);
561 2 : sa.sa_flags = 0;
562 :
563 2 : if (::sigaction(signal_number, &sa, nullptr) < 0)
564 MIS 0 : return make_error_code(std::errc::invalid_argument);
565 :
566 : // Clear stored flags
567 HIT 2 : state->registered_flags[signal_number] = signal_set::none;
568 : }
569 :
570 2 : *deletion_point = reg->next_in_set;
571 :
572 2 : if (registrations_[signal_number] == reg)
573 2 : registrations_[signal_number] = reg->next_in_table;
574 2 : if (reg->prev_in_table)
575 MIS 0 : reg->prev_in_table->next_in_table = reg->next_in_table;
576 HIT 2 : if (reg->next_in_table)
577 MIS 0 : reg->next_in_table->prev_in_table = reg->prev_in_table;
578 :
579 HIT 2 : --state->registration_count[signal_number];
580 2 : --registration_count_[signal_number];
581 :
582 2 : delete reg;
583 2 : return {};
584 4 : }
585 :
586 : inline std::error_code
587 92 : posix_signal_service::clear_signals(posix_signal& impl)
588 : {
589 : posix_signal_detail::signal_state* state =
590 92 : posix_signal_detail::get_signal_state();
591 92 : std::lock_guard state_lock(state->mutex);
592 92 : std::lock_guard lock(mutex_);
593 :
594 92 : std::error_code first_error;
595 :
596 172 : while (signal_registration* reg = impl.signals_)
597 : {
598 80 : int signal_number = reg->signal_number;
599 :
600 80 : if (state->registration_count[signal_number] == 1)
601 : {
602 74 : struct sigaction sa = {};
603 74 : sa.sa_handler = SIG_DFL;
604 74 : sigemptyset(&sa.sa_mask);
605 74 : sa.sa_flags = 0;
606 :
607 74 : if (::sigaction(signal_number, &sa, nullptr) < 0 && !first_error)
608 MIS 0 : first_error = make_error_code(std::errc::invalid_argument);
609 :
610 : // Clear stored flags
611 HIT 74 : state->registered_flags[signal_number] = signal_set::none;
612 : }
613 :
614 80 : impl.signals_ = reg->next_in_set;
615 :
616 80 : if (registrations_[signal_number] == reg)
617 80 : registrations_[signal_number] = reg->next_in_table;
618 80 : if (reg->prev_in_table)
619 MIS 0 : reg->prev_in_table->next_in_table = reg->next_in_table;
620 HIT 80 : if (reg->next_in_table)
621 6 : reg->next_in_table->prev_in_table = reg->prev_in_table;
622 :
623 80 : --state->registration_count[signal_number];
624 80 : --registration_count_[signal_number];
625 :
626 80 : delete reg;
627 80 : }
628 :
629 92 : if (first_error)
630 MIS 0 : return first_error;
631 HIT 92 : return {};
632 92 : }
633 :
634 : inline void
635 100 : posix_signal_service::cancel_wait(posix_signal& impl)
636 : {
637 100 : bool was_waiting = false;
638 100 : signal_op* op = nullptr;
639 :
640 : {
641 100 : std::lock_guard lock(mutex_);
642 100 : if (impl.waiting_)
643 : {
644 4 : was_waiting = true;
645 4 : impl.waiting_ = false;
646 4 : op = &impl.pending_op_;
647 : }
648 100 : }
649 :
650 100 : if (was_waiting)
651 : {
652 4 : if (op->ec_out)
653 4 : *op->ec_out = make_error_code(capy::error::canceled);
654 4 : if (op->signal_out)
655 4 : *op->signal_out = 0;
656 4 : op->d.post(op->h);
657 4 : sched_->work_finished();
658 : }
659 100 : }
660 :
661 : inline void
662 26 : posix_signal_service::start_wait(posix_signal& impl, signal_op* op)
663 : {
664 : {
665 26 : std::lock_guard lock(mutex_);
666 :
667 : // Check for queued signals first (signal arrived before wait started)
668 26 : signal_registration* reg = impl.signals_;
669 44 : while (reg)
670 : {
671 28 : if (reg->undelivered > 0)
672 : {
673 10 : --reg->undelivered;
674 10 : op->signal_number = reg->signal_number;
675 : // svc=nullptr: no work_finished needed since we never called work_started
676 10 : op->svc = nullptr;
677 10 : sched_->post(op);
678 10 : return;
679 : }
680 18 : reg = reg->next_in_set;
681 : }
682 :
683 : // No queued signals - wait for delivery
684 16 : impl.waiting_ = true;
685 : // svc=this: signal_op::operator() will call work_finished() to balance this
686 16 : op->svc = this;
687 16 : sched_->work_started();
688 26 : }
689 : }
690 :
691 : inline void
692 20 : posix_signal_service::deliver_signal(int signal_number)
693 : {
694 20 : if (signal_number < 0 || signal_number >= max_signal_number)
695 MIS 0 : return;
696 :
697 : posix_signal_detail::signal_state* state =
698 HIT 20 : posix_signal_detail::get_signal_state();
699 20 : std::lock_guard lock(state->mutex);
700 :
701 20 : posix_signal_service* service = state->service_list;
702 40 : while (service)
703 : {
704 20 : std::lock_guard svc_lock(service->mutex_);
705 :
706 20 : signal_registration* reg = service->registrations_[signal_number];
707 42 : while (reg)
708 : {
709 22 : posix_signal* impl = static_cast<posix_signal*>(reg->owner);
710 :
711 22 : if (impl->waiting_)
712 : {
713 12 : impl->waiting_ = false;
714 12 : impl->pending_op_.signal_number = signal_number;
715 12 : service->post(&impl->pending_op_);
716 : }
717 : else
718 : {
719 10 : ++reg->undelivered;
720 : }
721 :
722 22 : reg = reg->next_in_table;
723 : }
724 :
725 20 : service = service->next_;
726 20 : }
727 20 : }
728 :
729 : inline void
730 : posix_signal_service::work_started() noexcept
731 : {
732 : sched_->work_started();
733 : }
734 :
735 : inline void
736 12 : posix_signal_service::work_finished() noexcept
737 : {
738 12 : sched_->work_finished();
739 12 : }
740 :
741 : inline void
742 12 : posix_signal_service::post(signal_op* op)
743 : {
744 12 : sched_->post(op);
745 12 : }
746 :
747 : inline void
748 340 : posix_signal_service::add_service(posix_signal_service* service)
749 : {
750 : posix_signal_detail::signal_state* state =
751 340 : posix_signal_detail::get_signal_state();
752 340 : std::lock_guard lock(state->mutex);
753 :
754 340 : service->next_ = state->service_list;
755 340 : service->prev_ = nullptr;
756 340 : if (state->service_list)
757 5 : state->service_list->prev_ = service;
758 340 : state->service_list = service;
759 340 : }
760 :
761 : inline void
762 340 : posix_signal_service::remove_service(posix_signal_service* service)
763 : {
764 : posix_signal_detail::signal_state* state =
765 340 : posix_signal_detail::get_signal_state();
766 340 : std::lock_guard lock(state->mutex);
767 :
768 340 : if (service->next_ || service->prev_ || state->service_list == service)
769 : {
770 340 : if (state->service_list == service)
771 340 : state->service_list = service->next_;
772 340 : if (service->prev_)
773 MIS 0 : service->prev_->next_ = service->next_;
774 HIT 340 : if (service->next_)
775 5 : service->next_->prev_ = service->prev_;
776 340 : service->next_ = nullptr;
777 340 : service->prev_ = nullptr;
778 : }
779 340 : }
780 :
781 : // get_signal_service - factory function
782 :
783 : inline posix_signal_service&
784 340 : get_signal_service(capy::execution_context& ctx, scheduler& sched)
785 : {
786 340 : return ctx.make_service<posix_signal_service>(sched);
787 : }
788 :
789 : } // namespace detail
790 : } // namespace boost::corosio
791 :
792 : #endif // BOOST_COROSIO_POSIX
793 :
794 : #endif // BOOST_COROSIO_NATIVE_DETAIL_POSIX_POSIX_SIGNAL_SERVICE_HPP
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