Index/include / boost / corosio / native / detail / epoll / epoll_socket_service.hpp

include/boost/corosio/native/detail/epoll/epoll_socket_service.hpp

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include/boost/corosio/native/detail/epoll/epoll_socket_service.hpp
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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_EPOLL_EPOLL_SOCKET_SERVICE_HPP
11 #define BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_SOCKET_SERVICE_HPP
12
13 #include <boost/corosio/detail/platform.hpp>
14
15 #if BOOST_COROSIO_HAS_EPOLL
16
17 #include <boost/corosio/detail/config.hpp>
18 #include <boost/capy/ex/execution_context.hpp>
19 #include <boost/corosio/detail/socket_service.hpp>
20
21 #include <boost/corosio/native/detail/epoll/epoll_socket.hpp>
22 #include <boost/corosio/native/detail/epoll/epoll_scheduler.hpp>
23
24 #include <boost/corosio/detail/endpoint_convert.hpp>
25 #include <boost/corosio/detail/make_err.hpp>
26 #include <boost/corosio/detail/dispatch_coro.hpp>
27 #include <boost/corosio/detail/except.hpp>
28 #include <boost/capy/buffers.hpp>
29
30 #include <coroutine>
31 #include <mutex>
32 #include <unordered_map>
33 #include <utility>
34
35 #include <errno.h>
36 #include <netinet/in.h>
37 #include <netinet/tcp.h>
38 #include <sys/epoll.h>
39 #include <sys/socket.h>
40 #include <unistd.h>
41
42 /*
43 epoll Socket Implementation
44 ===========================
45
46 Each I/O operation follows the same pattern:
47 1. Try the syscall immediately (non-blocking socket)
48 2. If it succeeds or fails with a real error, post to completion queue
49 3. If EAGAIN/EWOULDBLOCK, register with epoll and wait
50
51 This "try first" approach avoids unnecessary epoll round-trips for
52 operations that can complete immediately (common for small reads/writes
53 on fast local connections).
54
55 One-Shot Registration
56 ---------------------
57 We use one-shot epoll registration: each operation registers, waits for
58 one event, then unregisters. This simplifies the state machine since we
59 don't need to track whether an fd is currently registered or handle
60 re-arming. The tradeoff is slightly more epoll_ctl calls, but the
61 simplicity is worth it.
62
63 Cancellation
64 ------------
65 See op.hpp for the completion/cancellation race handling via the
66 `registered` atomic. cancel() must complete pending operations (post
67 them with cancelled flag) so coroutines waiting on them can resume.
68 close_socket() calls cancel() first to ensure this.
69
70 Impl Lifetime with shared_ptr
71 -----------------------------
72 Socket impls use enable_shared_from_this. The service owns impls via
73 shared_ptr maps (socket_ptrs_) keyed by raw pointer for O(1) lookup and
74 removal. When a user calls close(), we call cancel() which posts pending
75 ops to the scheduler.
76
77 CRITICAL: The posted ops must keep the impl alive until they complete.
78 Otherwise the scheduler would process a freed op (use-after-free). The
79 cancel() method captures shared_from_this() into op.impl_ptr before
80 posting. When the op completes, impl_ptr is cleared, allowing the impl
81 to be destroyed if no other references exist.
82
83 Service Ownership
84 -----------------
85 epoll_socket_service owns all socket impls. destroy_impl() removes the
86 shared_ptr from the map, but the impl may survive if ops still hold
87 impl_ptr refs. shutdown() closes all sockets and clears the map; any
88 in-flight ops will complete and release their refs.
89 */
90
91 namespace boost::corosio::detail {
92
93 /** State for epoll socket service. */
94 class epoll_socket_state
95 {
96 public:
97 205 explicit epoll_socket_state(epoll_scheduler& sched) noexcept : sched_(sched)
98 {
99 205 }
100
101 epoll_scheduler& sched_;
102 std::mutex mutex_;
103 intrusive_list<epoll_socket> socket_list_;
104 std::unordered_map<epoll_socket*, std::shared_ptr<epoll_socket>>
105 socket_ptrs_;
106 };
107
108 /** epoll socket service implementation.
109
110 Inherits from socket_service to enable runtime polymorphism.
111 Uses key_type = socket_service for service lookup.
112 */
113 class BOOST_COROSIO_DECL epoll_socket_service final : public socket_service
114 {
115 public:
116 explicit epoll_socket_service(capy::execution_context& ctx);
117 ~epoll_socket_service() override;
118
119 epoll_socket_service(epoll_socket_service const&) = delete;
120 epoll_socket_service& operator=(epoll_socket_service const&) = delete;
121
122 void shutdown() override;
123
124 io_object::implementation* construct() override;
125 void destroy(io_object::implementation*) override;
126 void close(io_object::handle&) override;
127 std::error_code open_socket(tcp_socket::implementation& impl) override;
128
129 394532 epoll_scheduler& scheduler() const noexcept
130 {
131 394532 return state_->sched_;
132 }
133 void post(epoll_op* op);
134 void work_started() noexcept;
135 void work_finished() noexcept;
136
137 private:
138 std::unique_ptr<epoll_socket_state> state_;
139 };
140
141 //--------------------------------------------------------------------------
142 //
143 // Implementation
144 //
145 //--------------------------------------------------------------------------
146
147 // Register an op with the reactor, handling cached edge events.
148 // Called under the EAGAIN/EINPROGRESS path when speculative I/O failed.
149 inline void
150 2978 epoll_socket::register_op(
151 epoll_op& op,
152 epoll_op*& desc_slot,
153 bool& ready_flag,
154 bool& cancel_flag) noexcept
155 {
156 2978 svc_.work_started();
157
158 2978 std::lock_guard lock(desc_state_.mutex);
159 2978 bool io_done = false;
160 2978 if (ready_flag)
161 {
162 140 ready_flag = false;
163 140 op.perform_io();
164 140 io_done = (op.errn != EAGAIN && op.errn != EWOULDBLOCK);
165 140 if (!io_done)
166 140 op.errn = 0;
167 }
168
169 2978 if (cancel_flag)
170 {
171 93 cancel_flag = false;
172 93 op.cancelled.store(true, std::memory_order_relaxed);
173 }
174
175 2978 if (io_done || op.cancelled.load(std::memory_order_acquire))
176 {
177 93 svc_.post(&op);
178 93 svc_.work_finished();
179 }
180 else
181 {
182 2885 desc_slot = &op;
183 }
184 2978 }
185
186 inline void
187 104 epoll_op::canceller::operator()() const noexcept
188 {
189 104 op->cancel();
190 104 }
191
192 inline void
193 ✗ epoll_connect_op::cancel() noexcept
194 {
195 ✗ if (socket_impl_)
196 ✗ socket_impl_->cancel_single_op(*this);
197 else
198 ✗ request_cancel();
199 ✗ }
200
201 inline void
202 98 epoll_read_op::cancel() noexcept
203 {
204 98 if (socket_impl_)
205 98 socket_impl_->cancel_single_op(*this);
206 else
207 ✗ request_cancel();
208 98 }
209
210 inline void
211 ✗ epoll_write_op::cancel() noexcept
212 {
213 ✗ if (socket_impl_)
214 ✗ socket_impl_->cancel_single_op(*this);
215 else
216 ✗ request_cancel();
217 ✗ }
218
219 inline void
220 63542 epoll_op::operator()()
221 {
222 63542 stop_cb.reset();
223
224 63542 socket_impl_->svc_.scheduler().reset_inline_budget();
225
226 63542 if (cancelled.load(std::memory_order_acquire))
227 203 *ec_out = capy::error::canceled;
228 63339 else if (errn != 0)
229 ✗ *ec_out = make_err(errn);
230 63339 else if (is_read_operation() && bytes_transferred == 0)
231 ✗ *ec_out = capy::error::eof;
232 else
233 63339 *ec_out = {};
234
235 63542 *bytes_out = bytes_transferred;
236
237 // Move to stack before resuming coroutine. The coroutine might close
238 // the socket, releasing the last wrapper ref. If impl_ptr were the
239 // last ref and we destroyed it while still in operator(), we'd have
240 // use-after-free. Moving to local ensures destruction happens at
241 // function exit, after all member accesses are complete.
242 63542 capy::executor_ref saved_ex(ex);
243 63542 std::coroutine_handle<> saved_h(h);
244 63542 auto prevent_premature_destruction = std::move(impl_ptr);
245 63542 dispatch_coro(saved_ex, saved_h).resume();
246 63542 }
247
248 inline void
249 2779 epoll_connect_op::operator()()
250 {
251 2779 stop_cb.reset();
252
253 2779 socket_impl_->svc_.scheduler().reset_inline_budget();
254
255 2779 bool success = (errn == 0 && !cancelled.load(std::memory_order_acquire));
256
257 // Cache endpoints on successful connect
258 2779 if (success && socket_impl_)
259 {
260 // Query local endpoint via getsockname (may fail, but remote is always known)
261 2778 endpoint local_ep;
262 2778 sockaddr_in local_addr{};
263 2778 socklen_t local_len = sizeof(local_addr);
264 2778 if (::getsockname(
265 2778 fd, reinterpret_cast<sockaddr*>(&local_addr), &local_len) == 0)
266 2778 local_ep = from_sockaddr_in(local_addr);
267 // Always cache remote endpoint; local may be default if getsockname failed
268 2778 static_cast<epoll_socket*>(socket_impl_)
269 2778 ->set_endpoints(local_ep, target_endpoint);
270 }
271
272 2779 if (cancelled.load(std::memory_order_acquire))
273 ✗ *ec_out = capy::error::canceled;
274 2779 else if (errn != 0)
275 1 *ec_out = make_err(errn);
276 else
277 2778 *ec_out = {};
278
279 // Move to stack before resuming. See epoll_op::operator()() for rationale.
280 2779 capy::executor_ref saved_ex(ex);
281 2779 std::coroutine_handle<> saved_h(h);
282 2779 auto prevent_premature_destruction = std::move(impl_ptr);
283 2779 dispatch_coro(saved_ex, saved_h).resume();
284 2779 }
285
286 8391 inline epoll_socket::epoll_socket(epoll_socket_service& svc) noexcept
287 8391 : svc_(svc)
288 {
289 8391 }
290
291 8391 inline epoll_socket::~epoll_socket() = default;
292
293 inline std::coroutine_handle<>
294 2779 epoll_socket::connect(
295 std::coroutine_handle<> h,
296 capy::executor_ref ex,
297 endpoint ep,
298 std::stop_token token,
299 std::error_code* ec)
300 {
301 2779 auto& op = conn_;
302
303 2779 sockaddr_in addr = detail::to_sockaddr_in(ep);
304 int result =
305 2779 ::connect(fd_, reinterpret_cast<sockaddr*>(&addr), sizeof(addr));
306
307 2779 if (result == 0)
308 {
309 ✗ sockaddr_in local_addr{};
310 ✗ socklen_t local_len = sizeof(local_addr);
311 ✗ if (::getsockname(
312 ✗ fd_, reinterpret_cast<sockaddr*>(&local_addr), &local_len) == 0)
313 ✗ local_endpoint_ = detail::from_sockaddr_in(local_addr);
314 ✗ remote_endpoint_ = ep;
315 }
316
317 2779 if (result == 0 || errno != EINPROGRESS)
318 {
319 ✗ int err = (result < 0) ? errno : 0;
320 ✗ if (svc_.scheduler().try_consume_inline_budget())
321 {
322 ✗ *ec = err ? make_err(err) : std::error_code{};
323 ✗ return dispatch_coro(ex, h);
324 }
325 ✗ op.reset();
326 ✗ op.h = h;
327 ✗ op.ex = ex;
328 ✗ op.ec_out = ec;
329 ✗ op.fd = fd_;
330 ✗ op.target_endpoint = ep;
331 ✗ op.start(token, this);
332 ✗ op.impl_ptr = shared_from_this();
333 ✗ op.complete(err, 0);
334 ✗ svc_.post(&op);
335 ✗ return std::noop_coroutine();
336 }
337
338 // EINPROGRESS — register with reactor
339 2779 op.reset();
340 2779 op.h = h;
341 2779 op.ex = ex;
342 2779 op.ec_out = ec;
343 2779 op.fd = fd_;
344 2779 op.target_endpoint = ep;
345 2779 op.start(token, this);
346 2779 op.impl_ptr = shared_from_this();
347
348 2779 register_op(
349 2779 op, desc_state_.connect_op, desc_state_.write_ready,
350 2779 desc_state_.connect_cancel_pending);
351 2779 return std::noop_coroutine();
352 }
353
354 inline std::coroutine_handle<>
355 158737 epoll_socket::read_some(
356 std::coroutine_handle<> h,
357 capy::executor_ref ex,
358 io_buffer_param param,
359 std::stop_token token,
360 std::error_code* ec,
361 std::size_t* bytes_out)
362 {
363 158737 auto& op = rd_;
364 158737 op.reset();
365
366 158737 capy::mutable_buffer bufs[epoll_read_op::max_buffers];
367 158737 op.iovec_count =
368 158737 static_cast<int>(param.copy_to(bufs, epoll_read_op::max_buffers));
369
370 158737 if (op.iovec_count == 0 || (op.iovec_count == 1 && bufs[0].size() == 0))
371 {
372 1 op.empty_buffer_read = true;
373 1 op.h = h;
374 1 op.ex = ex;
375 1 op.ec_out = ec;
376 1 op.bytes_out = bytes_out;
377 1 op.start(token, this);
378 1 op.impl_ptr = shared_from_this();
379 1 op.complete(0, 0);
380 1 svc_.post(&op);
381 1 return std::noop_coroutine();
382 }
383
384 317472 for (int i = 0; i < op.iovec_count; ++i)
385 {
386 158736 op.iovecs[i].iov_base = bufs[i].data();
387 158736 op.iovecs[i].iov_len = bufs[i].size();
388 }
389
390 // Speculative read
391 ssize_t n;
392 do
393 {
394 158736 n = ::readv(fd_, op.iovecs, op.iovec_count);
395 }
396 158736 while (n < 0 && errno == EINTR);
397
398 158736 if (n >= 0 || (errno != EAGAIN && errno != EWOULDBLOCK))
399 {
400 158537 int err = (n < 0) ? errno : 0;
401 158537 auto bytes = (n > 0) ? static_cast<std::size_t>(n) : std::size_t(0);
402
403 158537 if (svc_.scheduler().try_consume_inline_budget())
404 {
405 126876 if (err)
406 ✗ *ec = make_err(err);
407 126876 else if (n == 0)
408 5 *ec = capy::error::eof;
409 else
410 126871 *ec = {};
411 126876 *bytes_out = bytes;
412 126876 return dispatch_coro(ex, h);
413 }
414 31661 op.h = h;
415 31661 op.ex = ex;
416 31661 op.ec_out = ec;
417 31661 op.bytes_out = bytes_out;
418 31661 op.start(token, this);
419 31661 op.impl_ptr = shared_from_this();
420 31661 op.complete(err, bytes);
421 31661 svc_.post(&op);
422 31661 return std::noop_coroutine();
423 }
424
425 // EAGAIN — register with reactor
426 199 op.h = h;
427 199 op.ex = ex;
428 199 op.ec_out = ec;
429 199 op.bytes_out = bytes_out;
430 199 op.fd = fd_;
431 199 op.start(token, this);
432 199 op.impl_ptr = shared_from_this();
433
434 199 register_op(
435 199 op, desc_state_.read_op, desc_state_.read_ready,
436 199 desc_state_.read_cancel_pending);
437 199 return std::noop_coroutine();
438 }
439
440 inline std::coroutine_handle<>
441 158539 epoll_socket::write_some(
442 std::coroutine_handle<> h,
443 capy::executor_ref ex,
444 io_buffer_param param,
445 std::stop_token token,
446 std::error_code* ec,
447 std::size_t* bytes_out)
448 {
449 158539 auto& op = wr_;
450 158539 op.reset();
451
452 158539 capy::mutable_buffer bufs[epoll_write_op::max_buffers];
453 158539 op.iovec_count =
454 158539 static_cast<int>(param.copy_to(bufs, epoll_write_op::max_buffers));
455
456 158539 if (op.iovec_count == 0 || (op.iovec_count == 1 && bufs[0].size() == 0))
457 {
458 1 op.h = h;
459 1 op.ex = ex;
460 1 op.ec_out = ec;
461 1 op.bytes_out = bytes_out;
462 1 op.start(token, this);
463 1 op.impl_ptr = shared_from_this();
464 1 op.complete(0, 0);
465 1 svc_.post(&op);
466 1 return std::noop_coroutine();
467 }
468
469 317076 for (int i = 0; i < op.iovec_count; ++i)
470 {
471 158538 op.iovecs[i].iov_base = bufs[i].data();
472 158538 op.iovecs[i].iov_len = bufs[i].size();
473 }
474
475 // Speculative write
476 158538 msghdr msg{};
477 158538 msg.msg_iov = op.iovecs;
478 158538 msg.msg_iovlen = static_cast<std::size_t>(op.iovec_count);
479
480 ssize_t n;
481 do
482 {
483 158538 n = ::sendmsg(fd_, &msg, MSG_NOSIGNAL);
484 }
485 158538 while (n < 0 && errno == EINTR);
486
487 158538 if (n >= 0 || (errno != EAGAIN && errno != EWOULDBLOCK))
488 {
489 158538 int err = (n < 0) ? errno : 0;
490 158538 auto bytes = (n > 0) ? static_cast<std::size_t>(n) : std::size_t(0);
491
492 158538 if (svc_.scheduler().try_consume_inline_budget())
493 {
494 126858 *ec = err ? make_err(err) : std::error_code{};
495 126858 *bytes_out = bytes;
496 126858 return dispatch_coro(ex, h);
497 }
498 31680 op.h = h;
499 31680 op.ex = ex;
500 31680 op.ec_out = ec;
501 31680 op.bytes_out = bytes_out;
502 31680 op.start(token, this);
503 31680 op.impl_ptr = shared_from_this();
504 31680 op.complete(err, bytes);
505 31680 svc_.post(&op);
506 31680 return std::noop_coroutine();
507 }
508
509 // EAGAIN — register with reactor
510 ✗ op.h = h;
511 ✗ op.ex = ex;
512 ✗ op.ec_out = ec;
513 ✗ op.bytes_out = bytes_out;
514 ✗ op.fd = fd_;
515 ✗ op.start(token, this);
516 ✗ op.impl_ptr = shared_from_this();
517
518 ✗ register_op(
519 ✗ op, desc_state_.write_op, desc_state_.write_ready,
520 ✗ desc_state_.write_cancel_pending);
521 ✗ return std::noop_coroutine();
522 }
523
524 inline std::error_code
525 3 epoll_socket::shutdown(tcp_socket::shutdown_type what) noexcept
526 {
527 int how;
528 3 switch (what)
529 {
530 1 case tcp_socket::shutdown_receive:
531 1 how = SHUT_RD;
532 1 break;
533 1 case tcp_socket::shutdown_send:
534 1 how = SHUT_WR;
535 1 break;
536 1 case tcp_socket::shutdown_both:
537 1 how = SHUT_RDWR;
538 1 break;
539 ✗ default:
540 ✗ return make_err(EINVAL);
541 }
542 3 if (::shutdown(fd_, how) != 0)
543 ✗ return make_err(errno);
544 3 return {};
545 }
546
547 inline std::error_code
548 5 epoll_socket::set_no_delay(bool value) noexcept
549 {
550 5 int flag = value ? 1 : 0;
551 5 if (::setsockopt(fd_, IPPROTO_TCP, TCP_NODELAY, &flag, sizeof(flag)) != 0)
552 ✗ return make_err(errno);
553 5 return {};
554 }
555
556 inline bool
557 5 epoll_socket::no_delay(std::error_code& ec) const noexcept
558 {
559 5 int flag = 0;
560 5 socklen_t len = sizeof(flag);
561 5 if (::getsockopt(fd_, IPPROTO_TCP, TCP_NODELAY, &flag, &len) != 0)
562 {
563 ✗ ec = make_err(errno);
564 ✗ return false;
565 }
566 5 ec = {};
567 5 return flag != 0;
568 }
569
570 inline std::error_code
571 4 epoll_socket::set_keep_alive(bool value) noexcept
572 {
573 4 int flag = value ? 1 : 0;
574 4 if (::setsockopt(fd_, SOL_SOCKET, SO_KEEPALIVE, &flag, sizeof(flag)) != 0)
575 ✗ return make_err(errno);
576 4 return {};
577 }
578
579 inline bool
580 4 epoll_socket::keep_alive(std::error_code& ec) const noexcept
581 {
582 4 int flag = 0;
583 4 socklen_t len = sizeof(flag);
584 4 if (::getsockopt(fd_, SOL_SOCKET, SO_KEEPALIVE, &flag, &len) != 0)
585 {
586 ✗ ec = make_err(errno);
587 ✗ return false;
588 }
589 4 ec = {};
590 4 return flag != 0;
591 }
592
593 inline std::error_code
594 1 epoll_socket::set_receive_buffer_size(int size) noexcept
595 {
596 1 if (::setsockopt(fd_, SOL_SOCKET, SO_RCVBUF, &size, sizeof(size)) != 0)
597 ✗ return make_err(errno);
598 1 return {};
599 }
600
601 inline int
602 3 epoll_socket::receive_buffer_size(std::error_code& ec) const noexcept
603 {
604 3 int size = 0;
605 3 socklen_t len = sizeof(size);
606 3 if (::getsockopt(fd_, SOL_SOCKET, SO_RCVBUF, &size, &len) != 0)
607 {
608 ✗ ec = make_err(errno);
609 ✗ return 0;
610 }
611 3 ec = {};
612 3 return size;
613 }
614
615 inline std::error_code
616 1 epoll_socket::set_send_buffer_size(int size) noexcept
617 {
618 1 if (::setsockopt(fd_, SOL_SOCKET, SO_SNDBUF, &size, sizeof(size)) != 0)
619 ✗ return make_err(errno);
620 1 return {};
621 }
622
623 inline int
624 3 epoll_socket::send_buffer_size(std::error_code& ec) const noexcept
625 {
626 3 int size = 0;
627 3 socklen_t len = sizeof(size);
628 3 if (::getsockopt(fd_, SOL_SOCKET, SO_SNDBUF, &size, &len) != 0)
629 {
630 ✗ ec = make_err(errno);
631 ✗ return 0;
632 }
633 3 ec = {};
634 3 return size;
635 }
636
637 inline std::error_code
638 10 epoll_socket::set_linger(bool enabled, int timeout) noexcept
639 {
640 10 if (timeout < 0)
641 1 return make_err(EINVAL);
642 struct ::linger lg;
643 9 lg.l_onoff = enabled ? 1 : 0;
644 9 lg.l_linger = timeout;
645 9 if (::setsockopt(fd_, SOL_SOCKET, SO_LINGER, &lg, sizeof(lg)) != 0)
646 ✗ return make_err(errno);
647 9 return {};
648 }
649
650 inline tcp_socket::linger_options
651 3 epoll_socket::linger(std::error_code& ec) const noexcept
652 {
653 3 struct ::linger lg{};
654 3 socklen_t len = sizeof(lg);
655 3 if (::getsockopt(fd_, SOL_SOCKET, SO_LINGER, &lg, &len) != 0)
656 {
657 ✗ ec = make_err(errno);
658 ✗ return {};
659 }
660 3 ec = {};
661 3 return {.enabled = lg.l_onoff != 0, .timeout = lg.l_linger};
662 }
663
664 inline void
665 183 epoll_socket::cancel() noexcept
666 {
667 183 auto self = weak_from_this().lock();
668 183 if (!self)
669 ✗ return;
670
671 183 conn_.request_cancel();
672 183 rd_.request_cancel();
673 183 wr_.request_cancel();
674
675 183 epoll_op* conn_claimed = nullptr;
676 183 epoll_op* rd_claimed = nullptr;
677 183 epoll_op* wr_claimed = nullptr;
678 {
679 183 std::lock_guard lock(desc_state_.mutex);
680 183 if (desc_state_.connect_op == &conn_)
681 ✗ conn_claimed = std::exchange(desc_state_.connect_op, nullptr);
682 else
683 183 desc_state_.connect_cancel_pending = true;
684 183 if (desc_state_.read_op == &rd_)
685 3 rd_claimed = std::exchange(desc_state_.read_op, nullptr);
686 else
687 180 desc_state_.read_cancel_pending = true;
688 183 if (desc_state_.write_op == &wr_)
689 ✗ wr_claimed = std::exchange(desc_state_.write_op, nullptr);
690 else
691 183 desc_state_.write_cancel_pending = true;
692 183 }
693
694 183 if (conn_claimed)
695 {
696 ✗ conn_.impl_ptr = self;
697 ✗ svc_.post(&conn_);
698 ✗ svc_.work_finished();
699 }
700 183 if (rd_claimed)
701 {
702 3 rd_.impl_ptr = self;
703 3 svc_.post(&rd_);
704 3 svc_.work_finished();
705 }
706 183 if (wr_claimed)
707 {
708 ✗ wr_.impl_ptr = self;
709 ✗ svc_.post(&wr_);
710 ✗ svc_.work_finished();
711 }
712 183 }
713
714 inline void
715 98 epoll_socket::cancel_single_op(epoll_op& op) noexcept
716 {
717 98 auto self = weak_from_this().lock();
718 98 if (!self)
719 ✗ return;
720
721 98 op.request_cancel();
722
723 98 epoll_op** desc_op_ptr = nullptr;
724 98 if (&op == &conn_)
725 ✗ desc_op_ptr = &desc_state_.connect_op;
726 98 else if (&op == &rd_)
727 98 desc_op_ptr = &desc_state_.read_op;
728 ✗ else if (&op == &wr_)
729 ✗ desc_op_ptr = &desc_state_.write_op;
730
731 98 if (desc_op_ptr)
732 {
733 98 epoll_op* claimed = nullptr;
734 {
735 98 std::lock_guard lock(desc_state_.mutex);
736 98 if (*desc_op_ptr == &op)
737 98 claimed = std::exchange(*desc_op_ptr, nullptr);
738 ✗ else if (&op == &conn_)
739 ✗ desc_state_.connect_cancel_pending = true;
740 ✗ else if (&op == &rd_)
741 ✗ desc_state_.read_cancel_pending = true;
742 ✗ else if (&op == &wr_)
743 ✗ desc_state_.write_cancel_pending = true;
744 98 }
745 98 if (claimed)
746 {
747 98 op.impl_ptr = self;
748 98 svc_.post(&op);
749 98 svc_.work_finished();
750 }
751 }
752 98 }
753
754 inline void
755 25140 epoll_socket::close_socket() noexcept
756 {
757 25140 auto self = weak_from_this().lock();
758 25140 if (self)
759 {
760 25140 conn_.request_cancel();
761 25140 rd_.request_cancel();
762 25140 wr_.request_cancel();
763
764 25140 epoll_op* conn_claimed = nullptr;
765 25140 epoll_op* rd_claimed = nullptr;
766 25140 epoll_op* wr_claimed = nullptr;
767 {
768 25140 std::lock_guard lock(desc_state_.mutex);
769 25140 conn_claimed = std::exchange(desc_state_.connect_op, nullptr);
770 25140 rd_claimed = std::exchange(desc_state_.read_op, nullptr);
771 25140 wr_claimed = std::exchange(desc_state_.write_op, nullptr);
772 25140 desc_state_.read_ready = false;
773 25140 desc_state_.write_ready = false;
774 25140 desc_state_.read_cancel_pending = false;
775 25140 desc_state_.write_cancel_pending = false;
776 25140 desc_state_.connect_cancel_pending = false;
777 25140 }
778
779 25140 if (conn_claimed)
780 {
781 ✗ conn_.impl_ptr = self;
782 ✗ svc_.post(&conn_);
783 ✗ svc_.work_finished();
784 }
785 25140 if (rd_claimed)
786 {
787 1 rd_.impl_ptr = self;
788 1 svc_.post(&rd_);
789 1 svc_.work_finished();
790 }
791 25140 if (wr_claimed)
792 {
793 ✗ wr_.impl_ptr = self;
794 ✗ svc_.post(&wr_);
795 ✗ svc_.work_finished();
796 }
797
798 25140 if (desc_state_.is_enqueued_.load(std::memory_order_acquire))
799 94 desc_state_.impl_ref_ = self;
800 }
801
802 25140 if (fd_ >= 0)
803 {
804 5568 if (desc_state_.registered_events != 0)
805 5568 svc_.scheduler().deregister_descriptor(fd_);
806 5568 ::close(fd_);
807 5568 fd_ = -1;
808 }
809
810 25140 desc_state_.fd = -1;
811 25140 desc_state_.registered_events = 0;
812
813 25140 local_endpoint_ = endpoint{};
814 25140 remote_endpoint_ = endpoint{};
815 25140 }
816
817 205 inline epoll_socket_service::epoll_socket_service(capy::execution_context& ctx)
818 205 : state_(
819 std::make_unique<epoll_socket_state>(
820 205 ctx.use_service<epoll_scheduler>()))
821 {
822 205 }
823
824 410 inline epoll_socket_service::~epoll_socket_service() {}
825
826 inline void
827 205 epoll_socket_service::shutdown()
828 {
829 205 std::lock_guard lock(state_->mutex_);
830
831 205 while (auto* impl = state_->socket_list_.pop_front())
832 ✗ impl->close_socket();
833
834 // Don't clear socket_ptrs_ here. The scheduler shuts down after us and
835 // drains completed_ops_, calling destroy() on each queued op. If we
836 // released our shared_ptrs now, an epoll_op::destroy() could free the
837 // last ref to an impl whose embedded descriptor_state is still linked
838 // in the queue — use-after-free on the next pop(). Letting ~state_
839 // release the ptrs (during service destruction, after scheduler
840 // shutdown) keeps every impl alive until all ops have been drained.
841 205 }
842
843 inline io_object::implementation*
844 8391 epoll_socket_service::construct()
845 {
846 8391 auto impl = std::make_shared<epoll_socket>(*this);
847 8391 auto* raw = impl.get();
848
849 {
850 8391 std::lock_guard lock(state_->mutex_);
851 8391 state_->socket_list_.push_back(raw);
852 8391 state_->socket_ptrs_.emplace(raw, std::move(impl));
853 8391 }
854
855 8391 return raw;
856 8391 }
857
858 inline void
859 8391 epoll_socket_service::destroy(io_object::implementation* impl)
860 {
861 8391 auto* epoll_impl = static_cast<epoll_socket*>(impl);
862 8391 epoll_impl->close_socket();
863 8391 std::lock_guard lock(state_->mutex_);
864 8391 state_->socket_list_.remove(epoll_impl);
865 8391 state_->socket_ptrs_.erase(epoll_impl);
866 8391 }
867
868 inline std::error_code
869 2790 epoll_socket_service::open_socket(tcp_socket::implementation& impl)
870 {
871 2790 auto* epoll_impl = static_cast<epoll_socket*>(&impl);
872 2790 epoll_impl->close_socket();
873
874 2790 int fd = ::socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
875 2790 if (fd < 0)
876 ✗ return make_err(errno);
877
878 2790 epoll_impl->fd_ = fd;
879
880 // Register fd with epoll (edge-triggered mode)
881 2790 epoll_impl->desc_state_.fd = fd;
882 {
883 2790 std::lock_guard lock(epoll_impl->desc_state_.mutex);
884 2790 epoll_impl->desc_state_.read_op = nullptr;
885 2790 epoll_impl->desc_state_.write_op = nullptr;
886 2790 epoll_impl->desc_state_.connect_op = nullptr;
887 2790 }
888 2790 scheduler().register_descriptor(fd, &epoll_impl->desc_state_);
889
890 2790 return {};
891 }
892
893 inline void
894 13959 epoll_socket_service::close(io_object::handle& h)
895 {
896 13959 static_cast<epoll_socket*>(h.get())->close_socket();
897 13959 }
898
899 inline void
900 63538 epoll_socket_service::post(epoll_op* op)
901 {
902 63538 state_->sched_.post(op);
903 63538 }
904
905 inline void
906 2978 epoll_socket_service::work_started() noexcept
907 {
908 2978 state_->sched_.work_started();
909 2978 }
910
911 inline void
912 195 epoll_socket_service::work_finished() noexcept
913 {
914 195 state_->sched_.work_finished();
915 195 }
916
917 } // namespace boost::corosio::detail
918
919 #endif // BOOST_COROSIO_HAS_EPOLL
920
921 #endif // BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_SOCKET_SERVICE_HPP
922