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

100.0% Lines (39 / 39) 100.0% Functions (11 / 11)

[ ] prev/next file

epoll_traits.hpp

f(x) Functions (11)

Function Calls Lines Blocks

Line	Hits	Source Code
1		//
2		// Copyright (c) 2026 Michael Vandeberg
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_TRAITS_HPP
11		#define BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_TRAITS_HPP
12
13		#include <boost/corosio/detail/platform.hpp>
14
15		#if BOOST_COROSIO_HAS_EPOLL
16
17		#include <boost/corosio/native/detail/make_err.hpp>
18		#include <boost/corosio/native/detail/reactor/reactor_descriptor_ops.hpp>
19		#include <boost/corosio/native/detail/reactor/reactor_descriptor_state.hpp>
20
21		#include <system_error>
22		#include <tuple>
23
24		#include <errno.h>
25		#include <netinet/in.h>
26		#include <sys/socket.h>
27		#include <sys/uio.h>
28		#include <unistd.h>
29
30		/* epoll backend traits.
31
32		Captures the platform-specific behavior of the Linux epoll backend:
33		atomic SOCK_NONBLOCK\|SOCK_CLOEXEC on socket(), accept4() for
34		accepted connections, and sendmsg(MSG_NOSIGNAL) for writes.
35		*/
36
37		namespace boost::corosio::detail {
38
39		class epoll_scheduler;
40
41		struct epoll_traits
42		{
43		using scheduler_type = epoll_scheduler;
44		using desc_state_type = reactor_descriptor_state;
45
46		static constexpr bool needs_park_notification = false;
47
48		// No extra per-socket state or lifecycle hooks needed for epoll.
49		struct stream_socket_hook
50		{
51	197x	std::error_code on_set_option(
52		int fd,
53		int level,
54		int optname,
55		void const* data,
56		std::size_t size) noexcept
57		{
58	197x	if (::setsockopt(
59	197x	fd, level, optname, data, static_cast<socklen_t>(size)) !=
60		0)
61	5x	return make_err(errno);
62	192x	return {};
63		}
64	23373x	static void pre_shutdown(int) noexcept {}
65	7628x	static void pre_destroy(int) noexcept {}
66		};
67
68		struct write_policy
69		{
70	77x	static ssize_t write(int fd, iovec* iovecs, int count) noexcept
71		{
72	77x	msghdr msg{};
73	77x	msg.msg_iov = iovecs;
74	77x	msg.msg_iovlen = static_cast<std::size_t>(count);
75
76		ssize_t n;
77		do
78		{
79	78x	n = ::sendmsg(fd, &msg, MSG_NOSIGNAL);
80		}
81	78x	while (n < 0 && errno == EINTR);
82	77x	return n;
83		}
84
85		static ssize_t
86	99522x	write_one(int fd, void const* data, std::size_t size) noexcept
87		{
88		ssize_t n;
89		do
90		{
91	99523x	n = ::send(fd, data, size, MSG_NOSIGNAL);
92		}
93	99523x	while (n < 0 && errno == EINTR);
94	99522x	return n;
95		}
96		};
97
98		using descriptor_write_policy = detail::descriptor_write_policy;
99
100		struct accept_policy
101		{
102		static int
103	5055x	do_accept(int fd, sockaddr_storage& peer, socklen_t& addrlen) noexcept
104		{
105	5055x	addrlen = sizeof(peer);
106		int new_fd;
107		do
108		{
109	5056x	new_fd = ::accept4(
110		fd, reinterpret_cast<sockaddr*>(&peer), &addrlen,
111		SOCK_NONBLOCK \| SOCK_CLOEXEC);
112		}
113	5056x	while (new_fd < 0 && errno == EINTR);
114	5055x	return new_fd;
115		}
116		};
117
118		// Create a nonblocking, close-on-exec socket using Linux's atomic flags.
119	3185x	static int create_socket(int family, int type, int protocol) noexcept
120		{
121	3185x	return ::socket(family, type \| SOCK_NONBLOCK \| SOCK_CLOEXEC, protocol);
122		}
123
124		// Apply protocol-specific options after socket creation.
125		// For IP sockets, sets IPV6_V6ONLY on AF_INET6 (best-effort).
126	2703x	static std::error_code configure_ip_socket(int fd, int family) noexcept
127		{
128	2703x	if (family == AF_INET6)
129		{
130	23x	int one = 1;
131		std::ignore =
132	23x	::setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
133		}
134	2703x	return {};
135		}
136
137		// Apply protocol-specific options for acceptor sockets.
138		// For IP acceptors, sets IPV6_V6ONLY=0 (dual-stack, best-effort).
139	356x	static std::error_code configure_ip_acceptor(int fd, int family) noexcept
140		{
141	356x	if (family == AF_INET6)
142		{
143	11x	int val = 0;
144		std::ignore =
145	11x	::setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
146		}
147	356x	return {};
148		}
149
150		// No extra configuration needed for local (unix) sockets on epoll.
151	117x	static std::error_code configure_local_socket(int /fd/) noexcept
152		{
153	117x	return {};
154		}
155
156		// Non-mutating validation for fds adopted via assign(). Used when
157		// the caller retains fd ownership responsibility.
158	164x	static std::error_code validate_assigned_fd(int /fd/) noexcept
159		{
160	164x	return {};
161		}
162		};
163
164		} // namespace boost::corosio::detail
165
166		#endif // BOOST_COROSIO_HAS_EPOLL
167
168		#endif // BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_TRAITS_HPP
169