TLA Line data 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_SELECT_SELECT_TRAITS_HPP
11 : #define BOOST_COROSIO_NATIVE_DETAIL_SELECT_SELECT_TRAITS_HPP
12 :
13 : #include <boost/corosio/detail/platform.hpp>
14 :
15 : #if BOOST_COROSIO_HAS_SELECT
16 :
17 : #include <boost/corosio/native/detail/make_err.hpp>
18 : #include <boost/corosio/native/detail/reactor/reactor_descriptor_state.hpp>
19 :
20 : #include <system_error>
21 :
22 : #include <errno.h>
23 : #include <fcntl.h>
24 : #include <netinet/in.h>
25 : #include <sys/select.h>
26 : #include <sys/socket.h>
27 : #include <unistd.h>
28 :
29 : /* select backend traits.
30 :
31 : Captures the platform-specific behavior of the portable select() backend:
32 : manual fcntl for O_NONBLOCK/FD_CLOEXEC, FD_SETSIZE validation,
33 : conditional SO_NOSIGPIPE, sendmsg(MSG_NOSIGNAL) where available,
34 : and accept()+fcntl for accepted connections.
35 : */
36 :
37 : namespace boost::corosio::detail {
38 :
39 : class select_scheduler;
40 : struct select_descriptor_state;
41 :
42 : struct select_traits
43 : {
44 : using scheduler_type = select_scheduler;
45 : using desc_state_type = select_descriptor_state;
46 :
47 : static constexpr bool needs_write_notification = true;
48 :
49 : /// No extra per-socket state or lifecycle hooks needed for select.
50 : struct stream_socket_hook
51 : {
52 HIT 28 : std::error_code on_set_option(
53 : int fd, int level, int optname,
54 : void const* data, std::size_t size) noexcept
55 : {
56 28 : if (::setsockopt(
57 : fd, level, optname, data,
58 28 : static_cast<socklen_t>(size)) != 0)
59 MIS 0 : return make_err(errno);
60 HIT 28 : return {};
61 : }
62 31208 : static void pre_shutdown(int) noexcept {}
63 10379 : static void pre_destroy(int) noexcept {}
64 : };
65 :
66 : struct write_policy
67 : {
68 102843 : static ssize_t write(int fd, iovec* iovecs, int count) noexcept
69 : {
70 102843 : msghdr msg{};
71 102843 : msg.msg_iov = iovecs;
72 102843 : msg.msg_iovlen = static_cast<std::size_t>(count);
73 :
74 : #ifdef MSG_NOSIGNAL
75 102843 : constexpr int send_flags = MSG_NOSIGNAL;
76 : #else
77 : constexpr int send_flags = 0;
78 : #endif
79 :
80 : ssize_t n;
81 : do
82 : {
83 102843 : n = ::sendmsg(fd, &msg, send_flags);
84 : }
85 102843 : while (n < 0 && errno == EINTR);
86 102843 : return n;
87 : }
88 : };
89 :
90 : struct accept_policy
91 : {
92 6902 : static int do_accept(
93 : int fd, sockaddr_storage& peer, socklen_t& addrlen) noexcept
94 : {
95 6902 : addrlen = sizeof(peer);
96 : int new_fd;
97 : do
98 : {
99 6902 : new_fd = ::accept(
100 : fd, reinterpret_cast<sockaddr*>(&peer), &addrlen);
101 : }
102 6902 : while (new_fd < 0 && errno == EINTR);
103 :
104 6902 : if (new_fd < 0)
105 3451 : return new_fd;
106 :
107 3451 : if (new_fd >= FD_SETSIZE)
108 : {
109 MIS 0 : ::close(new_fd);
110 0 : errno = EINVAL;
111 0 : return -1;
112 : }
113 :
114 HIT 3451 : int flags = ::fcntl(new_fd, F_GETFL, 0);
115 3451 : if (flags == -1)
116 : {
117 MIS 0 : int err = errno;
118 0 : ::close(new_fd);
119 0 : errno = err;
120 0 : return -1;
121 : }
122 :
123 HIT 3451 : if (::fcntl(new_fd, F_SETFL, flags | O_NONBLOCK) == -1)
124 : {
125 MIS 0 : int err = errno;
126 0 : ::close(new_fd);
127 0 : errno = err;
128 0 : return -1;
129 : }
130 :
131 HIT 3451 : if (::fcntl(new_fd, F_SETFD, FD_CLOEXEC) == -1)
132 : {
133 MIS 0 : int err = errno;
134 0 : ::close(new_fd);
135 0 : errno = err;
136 0 : return -1;
137 : }
138 :
139 : #ifdef SO_NOSIGPIPE
140 : int one = 1;
141 : if (::setsockopt(
142 : new_fd, SOL_SOCKET, SO_NOSIGPIPE,
143 : &one, sizeof(one)) == -1)
144 : {
145 : int err = errno;
146 : ::close(new_fd);
147 : errno = err;
148 : return -1;
149 : }
150 : #endif
151 :
152 HIT 3451 : return new_fd;
153 : }
154 : };
155 :
156 : /// Create a plain socket (no atomic flags — select is POSIX-portable).
157 3596 : static int create_socket(int family, int type, int protocol) noexcept
158 : {
159 3596 : return ::socket(family, type, protocol);
160 : }
161 :
162 : /// Set O_NONBLOCK, FD_CLOEXEC; check FD_SETSIZE; optionally SO_NOSIGPIPE.
163 : /// Caller is responsible for closing fd on error.
164 3612 : static std::error_code set_fd_options(int fd) noexcept
165 : {
166 3612 : int flags = ::fcntl(fd, F_GETFL, 0);
167 3612 : if (flags == -1)
168 MIS 0 : return make_err(errno);
169 HIT 3612 : if (::fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
170 MIS 0 : return make_err(errno);
171 HIT 3612 : if (::fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
172 MIS 0 : return make_err(errno);
173 :
174 HIT 3612 : if (fd >= FD_SETSIZE)
175 MIS 0 : return make_err(EINVAL);
176 :
177 : #ifdef SO_NOSIGPIPE
178 : // SO_NOSIGPIPE is the primary defense against SIGPIPE on
179 : // platforms that don't support MSG_NOSIGNAL. A silent failure
180 : // here would leave the fd vulnerable to crashing the process
181 : // on a closed-peer write, so propagate the error.
182 : {
183 : int one = 1;
184 : if (::setsockopt(
185 : fd, SOL_SOCKET, SO_NOSIGPIPE, &one, sizeof(one)) != 0)
186 : return make_err(errno);
187 : }
188 : #endif
189 :
190 HIT 3612 : return {};
191 : }
192 :
193 : /// Apply protocol-specific options after socket creation.
194 : /// For IP sockets, sets IPV6_V6ONLY on AF_INET6.
195 : static std::error_code
196 3513 : configure_ip_socket(int fd, int family) noexcept
197 : {
198 3513 : if (family == AF_INET6)
199 : {
200 13 : int one = 1;
201 13 : if (::setsockopt(
202 13 : fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)) != 0)
203 MIS 0 : return make_err(errno);
204 : }
205 :
206 HIT 3513 : return set_fd_options(fd);
207 : }
208 :
209 : /// Apply protocol-specific options for acceptor sockets.
210 : /// For IP acceptors, sets IPV6_V6ONLY=0 (dual-stack).
211 : static std::error_code
212 63 : configure_ip_acceptor(int fd, int family) noexcept
213 : {
214 63 : if (family == AF_INET6)
215 : {
216 8 : int val = 0;
217 8 : if (::setsockopt(
218 8 : fd, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) != 0)
219 MIS 0 : return make_err(errno);
220 : }
221 :
222 HIT 63 : return set_fd_options(fd);
223 : }
224 :
225 : /// Apply options for local (unix) sockets.
226 : static std::error_code
227 36 : configure_local_socket(int fd) noexcept
228 : {
229 36 : return set_fd_options(fd);
230 : }
231 : };
232 :
233 : } // namespace boost::corosio::detail
234 :
235 : #endif // BOOST_COROSIO_HAS_SELECT
236 :
237 : #endif // BOOST_COROSIO_NATIVE_DETAIL_SELECT_SELECT_TRAITS_HPP
|
