Index/include / boost / corosio / native / detail / iocp / win_validate_handle.hpp

include/boost/corosio/native/detail/iocp/win_validate_handle.hpp

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win_validate_handle.hpp
f(x) Functions (6)
Function Calls Lines Branches Blocks
long (*boost::corosio::detail::win_nt::ntdll_proc<long (*)(void*, boost::corosio::detail::win_nt::io_status_block*, void*, unsigned long, int)>(char const*))(void*, boost::corosio::detail::win_nt::io_status_block*, void*, unsigned long, int) :93 11x 75.0% 50.0% 83.3% long (*boost::corosio::detail::win_nt::ntdll_proc<long (*)(void*, int, void*, unsigned long, unsigned long*)>(char const*))(void*, int, void*, unsigned long, unsigned long*) :93 4x 75.0% 50.0% 83.3% boost::corosio::detail::win_nt::query_information_file() :102 302x 100.0% 75.0% 100.0% boost::corosio::detail::win_nt::query_object() :110 2828x 100.0% 75.0% 100.0% boost::corosio::detail::validate_overlapped_handle(void*, boost::corosio::detail::handle_kind) :134 320x 95.7% 90.0% 96.8% boost::corosio::detail::validate_object_handle(void*) :216 2832x 89.3% 84.6% 91.2%
Line Branch TLA Hits 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_IOCP_WIN_VALIDATE_HANDLE_HPP
11 #define BOOST_COROSIO_NATIVE_DETAIL_IOCP_WIN_VALIDATE_HANDLE_HPP
12
13 #include <boost/corosio/detail/platform.hpp>
14
15 #if BOOST_COROSIO_HAS_IOCP
16
17 #include <boost/corosio/native/detail/iocp/win_windows.hpp>
18
19 #include <cstdint>
20 #include <cstring>
21 #include <string_view>
22 #include <system_error>
23
24 /* The adopt-time gates for Windows handles -- the counterpart of
25 validate_fd.hpp. A gate only inspects the handle. None performs I/O
26 or waits on it, so an auto-reset event or a semaphore keeps its
27 signal across a gate, accepted or rejected.
28
29 Synchronous-mode handles are rejected by querying the file mode
30 rather than by letting CreateIoCompletionPort fail: whether it
31 refuses such a handle is undocumented, and an overlapped ReadFile on
32 one silently runs to completion inside the call.
33 */
34
35 namespace boost::corosio::detail {
36
37 /// The adopting type; the gates differ per type.
38 enum class handle_kind
39 {
40 stream_file,
41 random_access_file,
42 stream_handle,
43 random_access_handle
44 };
45
46 namespace win_nt {
47
48 using ntstatus = LONG;
49
50 struct io_status_block
51 {
52 union
53 {
54 ntstatus Status;
55 void* Pointer;
56 };
57 ULONG_PTR Information;
58 };
59
60 using query_information_file_fn =
61 ntstatus(NTAPI*)(HANDLE, io_status_block*, void*, ULONG, int);
62 using query_object_fn = ntstatus(NTAPI*)(HANDLE, int, void*, ULONG, ULONG*);
63
64 inline constexpr int file_mode_information = 16;
65 inline constexpr int file_io_completion_notification_information = 41;
66 inline constexpr int object_basic_information = 0;
67 inline constexpr int object_type_information = 2;
68
69 inline constexpr ULONG file_synchronous_io_alert = 0x10;
70 inline constexpr ULONG file_synchronous_io_nonalert = 0x20;
71 inline constexpr ULONG file_skip_completion_port_on_success = 0x1;
72
73 struct object_basic_info
74 {
75 ULONG Attributes;
76 ACCESS_MASK GrantedAccess;
77 ULONG HandleCount;
78 ULONG PointerCount;
79 ULONG Reserved[10];
80 };
81
82 struct unicode_string
83 {
84 USHORT Length;
85 USHORT MaximumLength;
86 PWSTR Buffer;
87 };
88
89 // The two-step cast through void(*)() is the sanctioned FARPROC
90 // conversion; a direct cast trips -Wcast-function-type.
91 template<class Fn>
92 Fn
93 15x ntdll_proc(char const* name) noexcept
94 {
95
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 15x if (HMODULE h = ::GetModuleHandleW(L"ntdll.dll"))
96 return reinterpret_cast<Fn>(
97 15x reinterpret_cast<void (*)()>(::GetProcAddress(h, name)));
98 ✗ return nullptr;
99 }
100
101 inline query_information_file_fn
102 302x query_information_file() noexcept
103 {
104 static query_information_file_fn const fn =
105
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 302x ntdll_proc<query_information_file_fn>("NtQueryInformationFile");
106 302x return fn;
107 }
108
109 inline query_object_fn
110 2828x query_object() noexcept
111 {
112 static query_object_fn const fn =
113
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 2828x ntdll_proc<query_object_fn>("NtQueryObject");
114 2828x return fn;
115 }
116
117 } // namespace win_nt
118
119 /** Validate a handle for adoption by an overlapped type.
120
121 @param h The handle to inspect. Never read, written or waited on.
122 @param kind The adopting type.
123
124 @return `bad_file_descriptor` for a null, invalid or closed
125 handle; `operation_not_supported` for a console, a socket, a
126 synchronous-mode handle, a handle already in
127 skip-completion-port-on-success mode, a directory, a disk
128 handle adopted
129 by `win_stream_handle`, or a pipe adopted by a file type;
130 otherwise an empty code. A missing `ntdll` entry point fails
131 closed with `operation_not_supported`.
132 */
133 inline std::error_code
134 320x validate_overlapped_handle(HANDLE h, handle_kind kind) noexcept
135 {
136 auto const not_supported =
137 320x std::make_error_code(std::errc::operation_not_supported);
138
139
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 320x if (h == nullptr || h == INVALID_HANDLE_VALUE)
140 13x return std::make_error_code(std::errc::bad_file_descriptor);
141
142 307x ::SetLastError(NO_ERROR);
143 307x DWORD const type = ::GetFileType(h);
144
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 307x if (type == FILE_TYPE_UNKNOWN && ::GetLastError() != NO_ERROR)
145 1x return std::make_error_code(std::errc::bad_file_descriptor);
146
147 306x DWORD console_mode = 0;
148
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 306x if (type == FILE_TYPE_CHAR && ::GetConsoleMode(h, &console_mode))
149 4x return not_supported;
150
151 302x auto const query = win_nt::query_information_file();
152
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 302x if (!query)
153 ✗ return not_supported;
154 302x win_nt::io_status_block iosb{};
155 302x ULONG mode = 0;
156
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 302x if (query(h, &iosb, &mode, sizeof(mode), win_nt::file_mode_information) <
157 0)
158 ✗ return not_supported;
159
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 302x if (mode &
160 (win_nt::file_synchronous_io_alert |
161 win_nt::file_synchronous_io_nonalert))
162 21x return not_supported;
163
164 // A handle already in skip-on-success mode queues no packet for a
165 // synchronous success, so the op would never complete. The mode
166 // cannot be cleared. A failed query means the mode was never set.
167 281x ULONG notify = 0;
168 281x if (query(h, &iosb, &notify, sizeof(notify),
169
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 560x win_nt::file_io_completion_notification_information) >= 0 &&
170
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 279x (notify & win_nt::file_skip_completion_port_on_success))
171 4x return not_supported;
172
173 // A failed query (volumes, some devices) means "not a directory".
174 277x FILE_BASIC_INFO basic{};
175 277x if (::GetFileInformationByHandleEx(
176
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 551x h, FileBasicInfo, &basic, sizeof(basic)) &&
177
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 274x (basic.FileAttributes & FILE_ATTRIBUTE_DIRECTORY))
178 5x return not_supported;
179
180 // A SOCKET reports FILE_TYPE_PIPE but is no named pipe, and must be
181 // closed with closesocket, not CloseHandle. GetNamedPipeInfo fails
182 // on it with ERROR_INVALID_FUNCTION; on a pipe end opened without
183 // FILE_READ_ATTRIBUTES (a PIPE_ACCESS_OUTBOUND server) it fails
184 // with ERROR_ACCESS_DENIED, which is no reason to reject.
185 318x if (type == FILE_TYPE_PIPE &&
186
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 275x !::GetNamedPipeInfo(h, nullptr, nullptr, nullptr, nullptr) &&
187
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 3x ::GetLastError() != ERROR_ACCESS_DENIED)
188 1x return not_supported;
189
190
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 271x switch (kind)
191 {
192 32x case handle_kind::stream_handle:
193
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 32x if (type == FILE_TYPE_DISK)
194 2x return not_supported;
195 30x break;
196 216x case handle_kind::stream_file:
197 case handle_kind::random_access_file:
198
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 216x if (type == FILE_TYPE_PIPE)
199 4x return not_supported;
200 212x break;
201 23x case handle_kind::random_access_handle:
202 23x break;
203 }
204 265x return {};
205 }
206
207 /** Validate a handle for adoption by `win_object_handle`.
208
209 @return `bad_file_descriptor` for a null, invalid or closed
210 handle; `operation_not_supported` for a pseudo-handle, an
211 object type other than process, thread, event, semaphore or
212 waitable timer, a handle without `SYNCHRONIZE` access, or a
213 missing `ntdll` entry point; otherwise an empty code.
214 */
215 inline std::error_code
216 2832x validate_object_handle(HANDLE h) noexcept
217 {
218 auto const not_supported =
219 2832x std::make_error_code(std::errc::operation_not_supported);
220
221
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 2832x if (h == nullptr || h == INVALID_HANDLE_VALUE)
222 3x return std::make_error_code(std::errc::bad_file_descriptor);
223
224 // GetCurrentThread() and the other pseudo-handles (-2 .. -6) resolve
225 // per calling thread. -1 (GetCurrentProcess) is INVALID_HANDLE_VALUE
226 // and already rejected above.
227 2829x auto const v = reinterpret_cast<std::intptr_t>(h);
228
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 2829x if (v <= -2 && v >= -6)
229 1x return not_supported;
230
231 2828x auto const query = win_nt::query_object();
232
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 2828x if (!query)
233 ✗ return not_supported;
234
235 2828x win_nt::object_basic_info basic{};
236 2828x if (query(
237 h, win_nt::object_basic_information, &basic, sizeof(basic),
238
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 2828x nullptr) < 0)
239 1x return std::make_error_code(std::errc::bad_file_descriptor);
240
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 2827x if (!(basic.GrantedAccess & SYNCHRONIZE))
241 1x return not_supported;
242
243 alignas(8) unsigned char buf[1024];
244
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 2826x if (query(h, win_nt::object_type_information, buf, sizeof(buf), nullptr) <
245 0)
246 ✗ return not_supported;
247 win_nt::unicode_string name;
248 2826x std::memcpy(&name, buf, sizeof(name));
249
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 2826x if (!name.Buffer)
250 ✗ return not_supported;
251
252 // Waitable kinds the pool can satisfy without side effects on a
253 // thread the coroutine does not own. Mutant (a mutex) is excluded
254 // for that reason. File is excluded because a file object signals
255 // on any I/O completion; console input and change notifications
256 // are File objects and need their own handling.
257 static constexpr std::wstring_view accepted[] = {
258 L"Process", L"Thread", L"Event", L"Semaphore", L"Timer", L"Job"};
259 std::wstring_view const type_name(
260 2826x name.Buffer, name.Length / sizeof(wchar_t));
261 2826x bool ok = false;
262
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 19782x for (auto a : accepted)
263
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 16956x ok = ok || type_name == a;
264
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 2826x if (!ok)
265 4x return not_supported;
266
267 2822x return {};
268 }
269
270 } // namespace boost::corosio::detail
271
272 #endif // BOOST_COROSIO_HAS_IOCP
273
274 #endif
275