include/boost/corosio/native/detail/validate_fd.hpp
96.0% Lines (48 / 50)
100.0% Functions (4 / 4)
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boost::corosio::detail::validate_socket_fd(int, int, bool)
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boost::corosio::detail::validate_descriptor_fd(int)
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boost::corosio::detail::validate_file_fd(int)
:135
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boost::corosio::detail::ensure_nonblocking(int)
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| Line | TLA | Hits | Source Code |
|---|---|---|---|
| 1 | // | ||
| 2 | // Copyright (c) 2026 Steve Gerbino | ||
| 3 | // Copyright (c) 2026 Michael Vandeberg | ||
| 4 | // | ||
| 5 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | ||
| 6 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | ||
| 7 | // | ||
| 8 | // Official repository: https://github.com/cppalliance/corosio | ||
| 9 | // | ||
| 10 | |||
| 11 | #ifndef BOOST_COROSIO_NATIVE_DETAIL_VALIDATE_FD_HPP | ||
| 12 | #define BOOST_COROSIO_NATIVE_DETAIL_VALIDATE_FD_HPP | ||
| 13 | |||
| 14 | #include <boost/corosio/detail/platform.hpp> | ||
| 15 | |||
| 16 | #if BOOST_COROSIO_POSIX | ||
| 17 | |||
| 18 | #include <boost/corosio/native/detail/make_err.hpp> | ||
| 19 | |||
| 20 | #include <cerrno> | ||
| 21 | #include <system_error> | ||
| 22 | |||
| 23 | #include <fcntl.h> | ||
| 24 | #include <sys/socket.h> | ||
| 25 | #include <sys/stat.h> | ||
| 26 | |||
| 27 | namespace boost::corosio::detail { | ||
| 28 | |||
| 29 | /** Validate a caller-supplied socket fd for adoption. | ||
| 30 | |||
| 31 | Non-mutating: interrogates the fd without changing any of its | ||
| 32 | flags, so a rejected fd goes back to the caller untouched. | ||
| 33 | |||
| 34 | @param fd The descriptor to validate. | ||
| 35 | @param expected_type `SOCK_STREAM` or `SOCK_DGRAM`. | ||
| 36 | @param is_ip Accept `AF_INET`/`AF_INET6` when true, `AF_UNIX` | ||
| 37 | when false. | ||
| 38 | @return Empty on success; `EBADF`, `EAFNOSUPPORT`, `EPROTOTYPE`, | ||
| 39 | or the `errno` reported by the interrogating call. | ||
| 40 | */ | ||
| 41 | inline std::error_code | ||
| 42 | 385x | validate_socket_fd(int fd, int expected_type, bool is_ip) noexcept | |
| 43 | { | ||
| 44 | 385x | if (fd < 0) | |
| 45 | 14x | return make_err(EBADF); | |
| 46 | |||
| 47 | 371x | sockaddr_storage st{}; | |
| 48 | 371x | socklen_t st_len = sizeof(st); | |
| 49 | 371x | if (::getsockname(fd, reinterpret_cast<sockaddr*>(&st), &st_len) != 0) | |
| 50 | 5x | return make_err(errno); | |
| 51 | 366x | if (is_ip) | |
| 52 | { | ||
| 53 | 49x | if (st.ss_family != AF_INET && st.ss_family != AF_INET6) | |
| 54 | 6x | return make_err(EAFNOSUPPORT); | |
| 55 | } | ||
| 56 | 317x | else if (st.ss_family != AF_UNIX) | |
| 57 | { | ||
| 58 | 2x | return make_err(EAFNOSUPPORT); | |
| 59 | } | ||
| 60 | |||
| 61 | 358x | int sock_type = 0; | |
| 62 | 358x | socklen_t opt_len = sizeof(sock_type); | |
| 63 | 358x | if (::getsockopt(fd, SOL_SOCKET, SO_TYPE, &sock_type, &opt_len) != 0) | |
| 64 | 15x | return make_err(errno); | |
| 65 | 343x | if (sock_type != expected_type) | |
| 66 | 20x | return make_err(EPROTOTYPE); | |
| 67 | |||
| 68 | 323x | return {}; | |
| 69 | } | ||
| 70 | |||
| 71 | /** Validate a caller-supplied fd for adoption by @ref posix_descriptor. | ||
| 72 | |||
| 73 | Non-mutating: interrogates the fd without changing any of its | ||
| 74 | flags, so a rejected fd goes back to the caller untouched. In | ||
| 75 | particular `O_NONBLOCK` is not applied here — see | ||
| 76 | @ref ensure_nonblocking. | ||
| 77 | |||
| 78 | The file-type test is a reject-list, not an accept-list. The | ||
| 79 | flagship descriptor kinds -- eventfd, timerfd, inotify, pidfd -- | ||
| 80 | are anonymous inodes whose `st_mode` type bits are all zero, so | ||
| 81 | an accept-list would silently reject exactly the fds this type | ||
| 82 | exists to carry. | ||
| 83 | |||
| 84 | @param fd The descriptor to validate. | ||
| 85 | @return Empty on success; `EBADF` for a closed or negative fd, | ||
| 86 | `operation_not_supported` for a regular file, directory or | ||
| 87 | block device, or the `errno` reported by `fstat`. | ||
| 88 | */ | ||
| 89 | inline std::error_code | ||
| 90 | 62x | validate_descriptor_fd(int fd) noexcept | |
| 91 | { | ||
| 92 | 62x | if (fd < 0) | |
| 93 | 3x | return make_err(EBADF); | |
| 94 | |||
| 95 | 59x | struct stat st{}; | |
| 96 | 59x | if (::fstat(fd, &st) != 0) | |
| 97 | 1x | return make_err(errno); | |
| 98 | |||
| 99 | // Regular files, block devices and directories are the province of | ||
| 100 | // stream_file / random_access_file, whose assign() already adopts | ||
| 101 | // them; a reactor cannot report readiness for them anyway. | ||
| 102 | 58x | switch (st.st_mode & S_IFMT) | |
| 103 | { | ||
| 104 | 6x | case S_IFREG: | |
| 105 | case S_IFBLK: | ||
| 106 | case S_IFDIR: | ||
| 107 | 6x | return std::make_error_code(std::errc::operation_not_supported); | |
| 108 | 52x | default: | |
| 109 | 52x | return {}; | |
| 110 | } | ||
| 111 | } | ||
| 112 | |||
| 113 | /** Validate a caller-supplied fd for adoption by a file object. | ||
| 114 | |||
| 115 | Non-mutating. Accepts the kinds a file object can position and | ||
| 116 | read: regular files, block devices, and character devices such | ||
| 117 | as /dev/null and /dev/zero. | ||
| 118 | |||
| 119 | This is an accept-list, the inverse of @ref validate_descriptor_fd's | ||
| 120 | reject-list: a file object needs a positionable fd, and the | ||
| 121 | anonymous inodes that motivate the descriptor reject-list are | ||
| 122 | exactly what a file object cannot use. | ||
| 123 | |||
| 124 | `S_IFCHR` is deliberately broad: it admits `/dev/null` and | ||
| 125 | `/dev/zero`, but also non-seekable character devices such as a | ||
| 126 | tty. Those pass here and then fail loudly at first I/O on the | ||
| 127 | POSIX backends, where `preadv`/`pwritev` report `ESPIPE`. | ||
| 128 | |||
| 129 | @param fd The descriptor to validate. | ||
| 130 | @return Empty on success; `EBADF` for a closed or negative fd, | ||
| 131 | `operation_not_supported` for a directory or a descriptor | ||
| 132 | with no file position, or the `errno` from `fstat`. | ||
| 133 | */ | ||
| 134 | inline std::error_code | ||
| 135 | 23x | validate_file_fd(int fd) noexcept | |
| 136 | { | ||
| 137 | 23x | if (fd < 0) | |
| 138 | 4x | return make_err(EBADF); | |
| 139 | |||
| 140 | 19x | struct stat st{}; | |
| 141 | 19x | if (::fstat(fd, &st) != 0) | |
| 142 | ✗ | return make_err(errno); | |
| 143 | |||
| 144 | 19x | switch (st.st_mode & S_IFMT) | |
| 145 | { | ||
| 146 | 14x | case S_IFREG: | |
| 147 | case S_IFBLK: | ||
| 148 | case S_IFCHR: | ||
| 149 | 14x | return {}; | |
| 150 | 5x | default: | |
| 151 | 5x | return std::make_error_code(std::errc::operation_not_supported); | |
| 152 | } | ||
| 153 | } | ||
| 154 | |||
| 155 | /** Put a descriptor into non-blocking mode, idempotently. | ||
| 156 | |||
| 157 | Called lazily on the first `read_some` / `write_some`, never from | ||
| 158 | `assign()`. The change is permanent: `O_NONBLOCK` lives on the | ||
| 159 | shared open file description, so restoring it later would race | ||
| 160 | every other holder of that description. A `wait()`-only user | ||
| 161 | never reaches this function and their fd is never modified. | ||
| 162 | |||
| 163 | @param fd The descriptor to modify. | ||
| 164 | @return Empty on success, otherwise the `errno` from `fcntl`. | ||
| 165 | */ | ||
| 166 | inline std::error_code | ||
| 167 | 32x | ensure_nonblocking(int fd) noexcept | |
| 168 | { | ||
| 169 | 32x | int flags = ::fcntl(fd, F_GETFL, 0); | |
| 170 | 32x | if (flags < 0) | |
| 171 | 1x | return make_err(errno); | |
| 172 | 31x | if (flags & O_NONBLOCK) | |
| 173 | 3x | return {}; | |
| 174 | 28x | if (::fcntl(fd, F_SETFL, flags | O_NONBLOCK) < 0) | |
| 175 | ✗ | return make_err(errno); | |
| 176 | 28x | return {}; | |
| 177 | } | ||
| 178 | |||
| 179 | } // namespace boost::corosio::detail | ||
| 180 | |||
| 181 | #endif // BOOST_COROSIO_POSIX | ||
| 182 | |||
| 183 | #endif // BOOST_COROSIO_NATIVE_DETAIL_VALIDATE_FD_HPP | ||
| 184 |