src/corosio/src/host_name.cpp

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host_name.cpp

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boost::corosio::host_name[abi:cxx11]() :51 6x 66.7% 43.3% 27.1%

Line	Branch	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
13			#include <stdexcept>
14			#include <string>
15
16			#if BOOST_COROSIO_POSIX
17			#include <cerrno>
18			#include <cstring>
19			#include <unistd.h>
20			#elif BOOST_COROSIO_HAS_IOCP
21			#include <windows.h>
22			#endif
23
24			namespace boost::corosio {
25
26			#if BOOST_COROSIO_POSIX
27
28			std::string
29			host_name()
30			{
31			// 256 exceeds POSIX's _POSIX_HOST_NAME_MAX floor of 255 and
32			// every mainstream OS's actual cap (Linux 64, macOS/BSD 255).
33			char buf[256];
34			if (::gethostname(buf, sizeof(buf)) != 0)
35			{
36			int e = errno;
37			throw std::runtime_error(
38			std::string("gethostname failed: ") + std::strerror(e));
39			}
40
41			// POSIX does not guarantee NUL termination on truncation.
42			if (std::memchr(buf, '\0', sizeof(buf)) == nullptr)
43			throw std::runtime_error("gethostname: hostname truncated");
44
45			return std::string(buf);
46			}
47
48			#elif BOOST_COROSIO_HAS_IOCP
49
50			std::string
51		6x	host_name()
52			{
53			// Size query: returns ERROR_MORE_DATA and writes the required
54			// wide-char count (including the trailing NUL) into `size`.
55		6x	DWORD size = 0;
56	1/1 ✓ Branch 2 → 3 taken 6 times.	6x	BOOL ok = ::GetComputerNameExW(
57			ComputerNameDnsHostname, nullptr, &size);
58	1/1 ✓ Branch 3 → 4 taken 6 times.	6x	DWORD err = ::GetLastError();
59	1/2 ✗ Branch 4 → 5 not taken. ✓ Branch 4 → 8 taken 6 times.	6x	if (ok)
60			{
61			throw std::runtime_error(
62		✗	"GetComputerNameExW (size query) unexpectedly succeeded");
63			}
64	1/2 ✗ Branch 8 → 9 not taken. ✓ Branch 8 → 16 taken 6 times.	6x	if (err != ERROR_MORE_DATA)
65			{
66			throw std::runtime_error(
67		✗	"GetComputerNameExW (size query) failed: error " +
68		✗	std::to_string(err));
69			}
70
71			// On success, GetComputerNameExW rewrites `size` to the count
72			// without the NUL, so resize(size) below trims to the hostname.
73	1/1 ✓ Branch 18 → 19 taken 6 times.	6x	std::wstring wide(size, L'\0');
74	2/3 ✓ Branch 21 → 22 taken 6 times. ✗ Branch 22 → 23 not taken. ✓ Branch 22 → 31 taken 6 times.	6x	if (!::GetComputerNameExW(
75			ComputerNameDnsHostname, wide.data(), &size))
76			{
77			throw std::runtime_error(
78		✗	"GetComputerNameExW failed: error " +
79		✗	std::to_string(::GetLastError()));
80			}
81	1/1 ✓ Branch 31 → 32 taken 6 times.	6x	wide.resize(size);
82
83	1/1 ✓ Branch 34 → 35 taken 6 times.	6x	int needed = ::WideCharToMultiByte(
84		6x	CP_UTF8, 0, wide.data(), static_cast<int>(wide.size()),
85			nullptr, 0, nullptr, nullptr);
86	1/2 ✗ Branch 35 → 36 not taken. ✓ Branch 35 → 44 taken 6 times.	6x	if (needed <= 0)
87			{
88			throw std::runtime_error(
89		✗	"WideCharToMultiByte (size query) failed: error " +
90		✗	std::to_string(::GetLastError()));
91			}
92
93	1/1 ✓ Branch 46 → 47 taken 6 times.	6x	std::string out(static_cast<std::size_t>(needed), '\0');
94	1/1 ✓ Branch 51 → 52 taken 6 times.	12x	int written = ::WideCharToMultiByte(
95		6x	CP_UTF8, 0, wide.data(), static_cast<int>(wide.size()),
96			out.data(), needed, nullptr, nullptr);
97	1/2 ✗ Branch 52 → 53 not taken. ✓ Branch 52 → 61 taken 6 times.	6x	if (written != needed)
98			{
99			throw std::runtime_error(
100		✗	"WideCharToMultiByte failed: error " +
101		✗	std::to_string(::GetLastError()));
102			}
103		6x	return out;
104		6x	}
105
106			#endif
107
108			} // namespace boost::corosio
109