1//===-- ConnectionGenericFileWindows.cpp ----------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "lldb/Host/windows/ConnectionGenericFileWindows.h"
10#include "lldb/Utility/LLDBLog.h"
11#include "lldb/Utility/Log.h"
12#include "lldb/Utility/Status.h"
13#include "lldb/Utility/Timeout.h"
14
15#include "llvm/ADT/STLExtras.h"
16#include "llvm/ADT/StringRef.h"
17#include "llvm/Support/ConvertUTF.h"
18
19using namespace lldb;
20using namespace lldb_private;
21
22namespace {
23// This is a simple helper class to package up the information needed to return
24// from a Read/Write operation function. Since there is a lot of code to be
25// run before exit regardless of whether the operation succeeded or failed,
26// combined with many possible return paths, this is the cleanest way to
27// represent it.
28class ReturnInfo {
29public:
30 void Set(size_t bytes, ConnectionStatus status, DWORD error_code) {
31 m_error = Status(error_code, eErrorTypeWin32);
32 m_bytes = bytes;
33 m_status = status;
34 }
35
36 void Set(size_t bytes, ConnectionStatus status, llvm::StringRef error_msg) {
37 m_error = Status::FromErrorString(str: error_msg.data());
38 m_bytes = bytes;
39 m_status = status;
40 }
41
42 size_t GetBytes() const { return m_bytes; }
43 ConnectionStatus GetStatus() const { return m_status; }
44 const Status &GetError() const { return m_error; }
45
46private:
47 Status m_error;
48 size_t m_bytes;
49 ConnectionStatus m_status;
50};
51}
52
53ConnectionGenericFile::ConnectionGenericFile()
54 : m_file(INVALID_HANDLE_VALUE), m_owns_file(false) {
55 ::ZeroMemory(&m_overlapped, sizeof(m_overlapped));
56 ::ZeroMemory(&m_file_position, sizeof(m_file_position));
57 InitializeEventHandles();
58}
59
60ConnectionGenericFile::ConnectionGenericFile(lldb::file_t file, bool owns_file)
61 : m_file(file), m_owns_file(owns_file) {
62 ::ZeroMemory(&m_overlapped, sizeof(m_overlapped));
63 ::ZeroMemory(&m_file_position, sizeof(m_file_position));
64 InitializeEventHandles();
65}
66
67ConnectionGenericFile::~ConnectionGenericFile() {
68 if (m_owns_file && IsConnected())
69 ::CloseHandle(m_file);
70
71 ::CloseHandle(m_event_handles[kBytesAvailableEvent]);
72 ::CloseHandle(m_event_handles[kInterruptEvent]);
73}
74
75void ConnectionGenericFile::InitializeEventHandles() {
76 m_event_handles[kInterruptEvent] = CreateEvent(NULL, FALSE, FALSE, NULL);
77
78 // Note, we should use a manual reset event for the hEvent argument of the
79 // OVERLAPPED. This is because both WaitForMultipleObjects and
80 // GetOverlappedResult (if you set the bWait argument to TRUE) will wait for
81 // the event to be signalled. If we use an auto-reset event,
82 // WaitForMultipleObjects will reset the event, return successfully, and then
83 // GetOverlappedResult will block since the event is no longer signalled.
84 m_event_handles[kBytesAvailableEvent] =
85 ::CreateEvent(NULL, TRUE, FALSE, NULL);
86}
87
88bool ConnectionGenericFile::IsConnected() const {
89 return m_file && (m_file != INVALID_HANDLE_VALUE);
90}
91
92lldb::ConnectionStatus ConnectionGenericFile::Connect(llvm::StringRef path,
93 Status *error_ptr) {
94 Log *log = GetLog(mask: LLDBLog::Connection);
95 LLDB_LOGF(log, "%p ConnectionGenericFile::Connect (url = '%s')",
96 static_cast<void *>(this), path.str().c_str());
97
98 if (!path.consume_front(Prefix: "file://")) {
99 if (error_ptr)
100 *error_ptr = Status::FromErrorStringWithFormat(
101 format: "unsupported connection URL: '%s'", path.str().c_str());
102 return eConnectionStatusError;
103 }
104
105 if (IsConnected()) {
106 ConnectionStatus status = Disconnect(error_ptr);
107 if (status != eConnectionStatusSuccess)
108 return status;
109 }
110
111 // Open the file for overlapped access. If it does not exist, create it. We
112 // open it overlapped so that we can issue asynchronous reads and then use
113 // WaitForMultipleObjects to allow the read to be interrupted by an event
114 // object.
115 std::wstring wpath;
116 if (!llvm::ConvertUTF8toWide(Source: path, Result&: wpath)) {
117 if (error_ptr)
118 *error_ptr = Status(1, eErrorTypeGeneric);
119 return eConnectionStatusError;
120 }
121 m_file = ::CreateFileW(wpath.c_str(), GENERIC_READ | GENERIC_WRITE,
122 FILE_SHARE_READ, NULL, OPEN_ALWAYS,
123 FILE_FLAG_OVERLAPPED, NULL);
124 if (m_file == INVALID_HANDLE_VALUE) {
125 if (error_ptr)
126 *error_ptr = Status(::GetLastError(), eErrorTypeWin32);
127 return eConnectionStatusError;
128 }
129
130 m_owns_file = true;
131 m_uri = path.str();
132 return eConnectionStatusSuccess;
133}
134
135lldb::ConnectionStatus ConnectionGenericFile::Disconnect(Status *error_ptr) {
136 Log *log = GetLog(mask: LLDBLog::Connection);
137 LLDB_LOGF(log, "%p ConnectionGenericFile::Disconnect ()",
138 static_cast<void *>(this));
139
140 if (!IsConnected())
141 return eConnectionStatusSuccess;
142
143 // Reset the handle so that after we unblock any pending reads, subsequent
144 // calls to Read() will see a disconnected state.
145 HANDLE old_file = m_file;
146 m_file = INVALID_HANDLE_VALUE;
147
148 // Set the disconnect event so that any blocking reads unblock, then cancel
149 // any pending IO operations.
150 ::CancelIoEx(old_file, &m_overlapped);
151
152 // Close the file handle if we owned it, but don't close the event handles.
153 // We could always reconnect with the same Connection instance.
154 if (m_owns_file)
155 ::CloseHandle(old_file);
156
157 ::ZeroMemory(&m_file_position, sizeof(m_file_position));
158 m_owns_file = false;
159 m_uri.clear();
160 return eConnectionStatusSuccess;
161}
162
163size_t ConnectionGenericFile::Read(void *dst, size_t dst_len,
164 const Timeout<std::micro> &timeout,
165 lldb::ConnectionStatus &status,
166 Status *error_ptr) {
167 ReturnInfo return_info;
168 BOOL result = 0;
169 DWORD bytes_read = 0;
170
171 if (error_ptr)
172 error_ptr->Clear();
173
174 if (!IsConnected()) {
175 return_info.Set(bytes: 0, status: eConnectionStatusNoConnection, error_msg: ERROR_INVALID_HANDLE);
176 goto finish;
177 }
178
179 m_overlapped.hEvent = m_event_handles[kBytesAvailableEvent];
180
181 result = ::ReadFile(m_file, dst, dst_len, NULL, &m_overlapped);
182 if (result || ::GetLastError() == ERROR_IO_PENDING) {
183 if (!result) {
184 // The expected return path. The operation is pending. Wait for the
185 // operation to complete or be interrupted.
186 DWORD milliseconds =
187 timeout
188 ? std::chrono::duration_cast<std::chrono::milliseconds>(*timeout)
189 .count()
190 : INFINITE;
191 DWORD wait_result = ::WaitForMultipleObjects(
192 std::size(m_event_handles), m_event_handles, FALSE, milliseconds);
193 // All of the events are manual reset events, so make sure we reset them
194 // to non-signalled.
195 switch (wait_result) {
196 case WAIT_OBJECT_0 + kBytesAvailableEvent:
197 break;
198 case WAIT_OBJECT_0 + kInterruptEvent:
199 return_info.Set(0, eConnectionStatusInterrupted, 0);
200 goto finish;
201 case WAIT_TIMEOUT:
202 return_info.Set(0, eConnectionStatusTimedOut, 0);
203 goto finish;
204 case WAIT_FAILED:
205 return_info.Set(bytes: 0, status: eConnectionStatusError, ::error_msg: GetLastError());
206 goto finish;
207 }
208 }
209 // The data is ready. Figure out how much was read and return;
210 if (!::GetOverlappedResult(m_file, &m_overlapped, &bytes_read, FALSE)) {
211 DWORD result_error = ::GetLastError();
212 // ERROR_OPERATION_ABORTED occurs when someone calls Disconnect() during
213 // a blocking read. This triggers a call to CancelIoEx, which causes the
214 // operation to complete and the result to be ERROR_OPERATION_ABORTED.
215 if (result_error == ERROR_HANDLE_EOF ||
216 result_error == ERROR_OPERATION_ABORTED ||
217 result_error == ERROR_BROKEN_PIPE)
218 return_info.Set(bytes: bytes_read, status: eConnectionStatusEndOfFile, error_msg: 0);
219 else
220 return_info.Set(bytes: bytes_read, status: eConnectionStatusError, error_msg: result_error);
221 } else if (bytes_read == 0)
222 return_info.Set(bytes: bytes_read, status: eConnectionStatusEndOfFile, error_msg: 0);
223 else
224 return_info.Set(bytes: bytes_read, status: eConnectionStatusSuccess, error_msg: 0);
225
226 goto finish;
227 } else if (::GetLastError() == ERROR_BROKEN_PIPE) {
228 // The write end of a pipe was closed. This is equivalent to EOF.
229 return_info.Set(0, eConnectionStatusEndOfFile, 0);
230 } else {
231 // An unknown error occurred. Fail out.
232 return_info.Set(0, eConnectionStatusError, ::GetLastError());
233 }
234 goto finish;
235
236finish:
237 status = return_info.GetStatus();
238 if (error_ptr)
239 *error_ptr = return_info.GetError().Clone();
240
241 // kBytesAvailableEvent is a manual reset event. Make sure it gets reset
242 // here so that any subsequent operations don't immediately see bytes
243 // available.
244 ResetEvent(m_event_handles[kBytesAvailableEvent]);
245
246 IncrementFilePointer(return_info.GetBytes());
247 Log *log = GetLog(mask: LLDBLog::Connection);
248 LLDB_LOGF(log,
249 "%p ConnectionGenericFile::Read() handle = %p, dst = %p, "
250 "dst_len = %zu) => %zu, error = %s",
251 static_cast<void *>(this), m_file, dst, dst_len,
252 return_info.GetBytes(), return_info.GetError().AsCString());
253
254 return return_info.GetBytes();
255}
256
257size_t ConnectionGenericFile::Write(const void *src, size_t src_len,
258 lldb::ConnectionStatus &status,
259 Status *error_ptr) {
260 ReturnInfo return_info;
261 DWORD bytes_written = 0;
262 BOOL result = 0;
263
264 if (error_ptr)
265 error_ptr->Clear();
266
267 if (!IsConnected()) {
268 return_info.Set(0, eConnectionStatusNoConnection, ERROR_INVALID_HANDLE);
269 goto finish;
270 }
271
272 m_overlapped.hEvent = NULL;
273
274 // Writes are not interruptible like reads are, so just block until it's
275 // done.
276 result = ::WriteFile(m_file, src, src_len, NULL, &m_overlapped);
277 if (!result && ::GetLastError() != ERROR_IO_PENDING) {
278 return_info.Set(0, eConnectionStatusError, ::GetLastError());
279 goto finish;
280 }
281
282 if (!::GetOverlappedResult(m_file, &m_overlapped, &bytes_written, TRUE)) {
283 return_info.Set(bytes_written, eConnectionStatusError, ::GetLastError());
284 goto finish;
285 }
286
287 return_info.Set(bytes: bytes_written, status: eConnectionStatusSuccess, error_msg: 0);
288 goto finish;
289
290finish:
291 status = return_info.GetStatus();
292 if (error_ptr)
293 *error_ptr = return_info.GetError().Clone();
294
295 IncrementFilePointer(return_info.GetBytes());
296 Log *log = GetLog(mask: LLDBLog::Connection);
297 LLDB_LOGF(log,
298 "%p ConnectionGenericFile::Write() handle = %p, src = %p, "
299 "src_len = %zu) => %zu, error = %s",
300 static_cast<void *>(this), m_file, src, src_len,
301 return_info.GetBytes(), return_info.GetError().AsCString());
302 return return_info.GetBytes();
303}
304
305std::string ConnectionGenericFile::GetURI() { return m_uri; }
306
307bool ConnectionGenericFile::InterruptRead() {
308 return ::SetEvent(m_event_handles[kInterruptEvent]);
309}
310
311void ConnectionGenericFile::IncrementFilePointer(DWORD amount) {
312 LARGE_INTEGER old_pos;
313 old_pos.HighPart = m_overlapped.OffsetHigh;
314 old_pos.LowPart = m_overlapped.Offset;
315 old_pos.QuadPart += amount;
316 m_overlapped.Offset = old_pos.LowPart;
317 m_overlapped.OffsetHigh = old_pos.HighPart;
318}
319

source code of lldb/source/Host/windows/ConnectionGenericFileWindows.cpp