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_REACTOR_REACTOR_DESCRIPTOR_OPS_HPP
      11                 : #define BOOST_COROSIO_NATIVE_DETAIL_REACTOR_REACTOR_DESCRIPTOR_OPS_HPP
      12                 : 
      13                 : #include <boost/corosio/detail/platform.hpp>
      14                 : 
      15                 : #if BOOST_COROSIO_POSIX
      16                 : 
      17                 : #include <cstddef>
      18                 : 
      19                 : #include <errno.h>
      20                 : #include <sys/types.h>
      21                 : #include <sys/uio.h>
      22                 : #include <unistd.h>
      23                 : 
      24                 : namespace boost::corosio::detail {
      25                 : 
      26                 : /* Write policy shared by every reactor backend's descriptor ops.
      27                 : 
      28                 :    Descriptors are not sockets: sendmsg() fails with ENOTSOCK on a pipe
      29                 :    or character device, so the write path is writev()/write() and
      30                 :    SIGPIPE suppression is structurally unavailable -- MSG_NOSIGNAL is a
      31                 :    send() flag and SO_NOSIGPIPE a socket option. A write to a pipe whose
      32                 :    read end has closed raises SIGPIPE, exactly as a plain write(2)
      33                 :    would; callers install SIG_IGN.
      34                 : */
      35                 : struct descriptor_write_policy
      36                 : {
      37 HIT           4 :     static ssize_t write(int fd, iovec* iovecs, int count) noexcept
      38                 :     {
      39                 :         ssize_t n;
      40                 :         do
      41                 :         {
      42               4 :             n = ::writev(fd, iovecs, count);
      43                 :         }
      44               4 :         while (n < 0 && errno == EINTR);
      45               4 :         return n;
      46                 :     }
      47                 : 
      48                 :     // Single-buffer fast path: skips the kernel's iov_iter setup.
      49                 :     static ssize_t
      50              18 :     write_one(int fd, void const* data, std::size_t size) noexcept
      51                 :     {
      52                 :         ssize_t n;
      53                 :         do
      54                 :         {
      55              18 :             n = ::write(fd, data, size);
      56                 :         }
      57              18 :         while (n < 0 && errno == EINTR);
      58              18 :         return n;
      59                 :     }
      60                 : };
      61                 : 
      62                 : } // namespace boost::corosio::detail
      63                 : 
      64                 : #endif // BOOST_COROSIO_POSIX
      65                 : 
      66                 : #endif // BOOST_COROSIO_NATIVE_DETAIL_REACTOR_REACTOR_DESCRIPTOR_OPS_HPP