src/corosio/src/host_name.cpp
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100.0% List of functions (1/0/1)
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boost::corosio::host_name[abi:cxx11]()
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| Line | TLA | Hits | Source Code |
|---|---|---|---|
| 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 | #include <boost/corosio/host_name.hpp> | ||
| 11 | #include <boost/corosio/detail/platform.hpp> | ||
| 12 | #include <boost/corosio/native/detail/make_err.hpp> | ||
| 13 | |||
| 14 | #include <string> | ||
| 15 | #include <system_error> | ||
| 16 | |||
| 17 | #if BOOST_COROSIO_POSIX | ||
| 18 | #include <cerrno> | ||
| 19 | #include <cstring> | ||
| 20 | #include <unistd.h> | ||
| 21 | #elif BOOST_COROSIO_HAS_IOCP | ||
| 22 | #include <windows.h> | ||
| 23 | #endif | ||
| 24 | |||
| 25 | namespace boost::corosio { | ||
| 26 | |||
| 27 | #if BOOST_COROSIO_POSIX | ||
| 28 | |||
| 29 | capy::io_result<std::string> | ||
| 30 | 16x | host_name() | |
| 31 | { | ||
| 32 | // 256 exceeds POSIX's _POSIX_HOST_NAME_MAX floor of 255 and | ||
| 33 | // every mainstream OS's actual cap (Linux 64, macOS/BSD 255). | ||
| 34 | char buf[256]; | ||
| 35 | 16x | if (::gethostname(buf, sizeof(buf)) != 0) | |
| 36 | 5x | return {detail::make_err(errno), {}}; | |
| 37 | |||
| 38 | // POSIX does not guarantee NUL termination on truncation. | ||
| 39 | 11x | if (std::memchr(buf, '\0', sizeof(buf)) == nullptr) | |
| 40 | 5x | return {make_error_code(std::errc::value_too_large), {}}; | |
| 41 | |||
| 42 | 18x | return {std::error_code{}, std::string(buf)}; | |
| 43 | } | ||
| 44 | |||
| 45 | #elif BOOST_COROSIO_HAS_IOCP | ||
| 46 | |||
| 47 | capy::io_result<std::string> | ||
| 48 | host_name() | ||
| 49 | { | ||
| 50 | // Size query: returns ERROR_MORE_DATA and writes the required | ||
| 51 | // wide-char count (including the trailing NUL) into `size`. | ||
| 52 | DWORD size = 0; | ||
| 53 | BOOL ok = ::GetComputerNameExW(ComputerNameDnsHostname, nullptr, &size); | ||
| 54 | DWORD err = ::GetLastError(); | ||
| 55 | if (ok) | ||
| 56 | { | ||
| 57 | // Can't-happen guard: a zero-length size query succeeding | ||
| 58 | // would leave `size` meaningless. | ||
| 59 | return {make_error_code(std::errc::protocol_error), {}}; | ||
| 60 | } | ||
| 61 | if (err != ERROR_MORE_DATA) | ||
| 62 | return {detail::make_err(static_cast<unsigned long>(err)), {}}; | ||
| 63 | |||
| 64 | // On success, GetComputerNameExW rewrites `size` to the count | ||
| 65 | // without the NUL, so resize(size) below trims to the hostname. | ||
| 66 | std::wstring wide(size, L'\0'); | ||
| 67 | if (!::GetComputerNameExW(ComputerNameDnsHostname, wide.data(), &size)) | ||
| 68 | return { | ||
| 69 | detail::make_err(static_cast<unsigned long>(::GetLastError())), {}}; | ||
| 70 | wide.resize(size); | ||
| 71 | |||
| 72 | int needed = ::WideCharToMultiByte( | ||
| 73 | CP_UTF8, 0, wide.data(), static_cast<int>(wide.size()), nullptr, 0, | ||
| 74 | nullptr, nullptr); | ||
| 75 | if (needed <= 0) | ||
| 76 | return { | ||
| 77 | detail::make_err(static_cast<unsigned long>(::GetLastError())), {}}; | ||
| 78 | |||
| 79 | std::string out(static_cast<std::size_t>(needed), '\0'); | ||
| 80 | int written = ::WideCharToMultiByte( | ||
| 81 | CP_UTF8, 0, wide.data(), static_cast<int>(wide.size()), out.data(), | ||
| 82 | needed, nullptr, nullptr); | ||
| 83 | if (written != needed) | ||
| 84 | return { | ||
| 85 | detail::make_err(static_cast<unsigned long>(::GetLastError())), {}}; | ||
| 86 | return {std::error_code{}, std::move(out)}; | ||
| 87 | } | ||
| 88 | |||
| 89 | #endif | ||
| 90 | |||
| 91 | } // namespace boost::corosio | ||
| 92 |