https://github.com/charles-zablit updated https://github.com/llvm/llvm-project/pull/175812
>From ca113a51b42d08382e0a9b6dd0636eba9f0d6ab4 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Tue, 13 Jan 2026 18:54:43 +0000 Subject: [PATCH 1/8] [lldb][windows] prevent IOHandlerProcessSTDIOWindows from consuming non text inputs --- .../Process/Windows/Common/ProcessWindows.cpp | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 127dd0f59e9ae..72043d16313cd 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -981,6 +981,9 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { HANDLE hInterrupt = (HANDLE)_get_osfhandle(m_pipe.GetReadFileDescriptor()); HANDLE waitHandles[2] = {hStdin, hInterrupt}; + DWORD consoleMode; + bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0; + while (true) { { std::lock_guard<std::mutex> guard(m_mutex); @@ -993,6 +996,20 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { case WAIT_FAILED: goto exit_loop; case WAIT_OBJECT_0: { + if (isConsole) { + INPUT_RECORD inputRecord; + DWORD numRead = 0; + if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead) || + numRead == 0) + goto exit_loop; + // We only care about text input. Ignore all non text input events and + // let other IOHandlers handle them. + if (inputRecord.EventType != KEY_EVENT || + !inputRecord.Event.KeyEvent.bKeyDown || + inputRecord.Event.KeyEvent.uChar.AsciiChar == 0) + break; + } + char ch = 0; DWORD read = 0; if (!ReadFile(hStdin, &ch, 1, &read, nullptr) || read != 1) >From 0fa56fa8a08ea20f031baddce32d85f4bef20a41 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Mon, 19 Jan 2026 13:50:09 +0000 Subject: [PATCH 2/8] consume non text input --- .../Process/Windows/Common/ProcessWindows.cpp | 28 +++++++++++-------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 72043d16313cd..ed02f243a5445 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -997,17 +997,23 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { goto exit_loop; case WAIT_OBJECT_0: { if (isConsole) { - INPUT_RECORD inputRecord; - DWORD numRead = 0; - if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead) || - numRead == 0) - goto exit_loop; - // We only care about text input. Ignore all non text input events and - // let other IOHandlers handle them. - if (inputRecord.EventType != KEY_EVENT || - !inputRecord.Event.KeyEvent.bKeyDown || - inputRecord.Event.KeyEvent.uChar.AsciiChar == 0) - break; + while (true) { + INPUT_RECORD inputRecord; + DWORD numRead = 0; + if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead) || + numRead == 0) + goto exit_loop; + + // We only care about text input. Consume all non text input events before letting ReadFile handle text input. + if (inputRecord.EventType == KEY_EVENT && + inputRecord.Event.KeyEvent.bKeyDown && + inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) + break; + + if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead) || + numRead == 0) + goto exit_loop; + } } char ch = 0; >From 275e21f2179b313337d56f0ada62f6fb70dd767d Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Mon, 19 Jan 2026 13:57:50 +0000 Subject: [PATCH 3/8] fix formatting --- lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index ed02f243a5445..0717f4f50a02a 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -1004,7 +1004,8 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { numRead == 0) goto exit_loop; - // We only care about text input. Consume all non text input events before letting ReadFile handle text input. + // We only care about text input. Consume all non text input events + // before letting ReadFile handle text input. if (inputRecord.EventType == KEY_EVENT && inputRecord.Event.KeyEvent.bKeyDown && inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) >From 4a6e01771e9c7b3081dfa8f6d4b69e01e5397e98 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Mon, 19 Jan 2026 15:50:09 +0000 Subject: [PATCH 4/8] fix control flow --- lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 0717f4f50a02a..2afb654775855 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -1000,8 +1000,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { while (true) { INPUT_RECORD inputRecord; DWORD numRead = 0; - if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead) || - numRead == 0) + if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) goto exit_loop; // We only care about text input. Consume all non text input events >From d2b6d061b3f4dee66a89af551ca5f69bbd1669ef Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Mon, 19 Jan 2026 17:32:34 +0000 Subject: [PATCH 5/8] fix control flow --- .../Plugins/Process/Windows/Common/ProcessWindows.cpp | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 2afb654775855..5847d47126b33 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -985,6 +985,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0; while (true) { + read_loop:; { std::lock_guard<std::mutex> guard(m_mutex); if (GetIsDone()) @@ -1003,6 +1004,9 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) goto exit_loop; + if (numRead == 0) + goto read_loop; + // We only care about text input. Consume all non text input events // before letting ReadFile handle text input. if (inputRecord.EventType == KEY_EVENT && @@ -1010,8 +1014,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) break; - if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead) || - numRead == 0) + if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead)) goto exit_loop; } } @@ -1045,7 +1048,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { } exit_loop:; - SetIsRunning(false); + SetIsRunning(false); } void Cancel() override { >From b158f2de731697f2bc8f0b5a55e5e42d621acd1f Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Tue, 20 Jan 2026 11:15:27 +0000 Subject: [PATCH 6/8] add comment --- lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 5847d47126b33..e73e86f745c0b 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -1004,6 +1004,8 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) goto exit_loop; + // If the pipe is empty, go back to waiting on + // WaitForMultipleObjects rather than ReadFile. if (numRead == 0) goto read_loop; @@ -1048,7 +1050,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { } exit_loop:; - SetIsRunning(false); + SetIsRunning(false); } void Cancel() override { >From 56e87c072141a8ac8a15a1bb434027ea84d2aa34 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Tue, 20 Jan 2026 14:33:32 +0000 Subject: [PATCH 7/8] remove secondary pipe --- .../Process/Windows/Common/ProcessWindows.cpp | 109 ++++++++++-------- 1 file changed, 58 insertions(+), 51 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index e73e86f745c0b..50917fdb336b5 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -956,7 +956,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { m_process(process), m_read_file(GetInputFD(), File::eOpenOptionReadOnly, false), m_write_file(conpty_input) { - m_pipe.CreateNew(); + m_interrupt_event = INVALID_HANDLE_VALUE; } ~IOHandlerProcessSTDIOWindows() override = default; @@ -967,9 +967,36 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { m_is_running = running; } + /// Peek the console for input. If it has any, drain the pipe until text input + /// is found or the pipe is empty. + /// + /// \param[in, out] hStdin + /// The handle to the standard input's pipe. + /// + /// \return + /// true if the pipe has text input. + llvm::Expected<bool> ConsoleHasTextInput(HANDLE hStdin) { + while (true) { + INPUT_RECORD inputRecord; + DWORD numRead = 0; + if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) + return llvm::createStringError("Failed to peek standard input."); + + if (numRead == 0) + return false; + + if (inputRecord.EventType == KEY_EVENT && + inputRecord.Event.KeyEvent.bKeyDown && + inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) + return true; + + if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead)) + return llvm::createStringError("Failed to read standard input."); + } + } + void Run() override { - if (!m_read_file.IsValid() || m_write_file == INVALID_HANDLE_VALUE || - !m_pipe.CanRead() || !m_pipe.CanWrite()) { + if (!m_read_file.IsValid() || m_write_file == INVALID_HANDLE_VALUE) { SetIsDone(true); return; } @@ -977,15 +1004,13 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { SetIsDone(false); SetIsRunning(true); - HANDLE hStdin = (HANDLE)_get_osfhandle(m_read_file.GetDescriptor()); - HANDLE hInterrupt = (HANDLE)_get_osfhandle(m_pipe.GetReadFileDescriptor()); - HANDLE waitHandles[2] = {hStdin, hInterrupt}; + HANDLE hStdin = m_read_file.GetWaitableHandle(); + HANDLE waitHandles[2] = {hStdin, m_interrupt_event}; DWORD consoleMode; bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0; while (true) { - read_loop:; { std::lock_guard<std::mutex> guard(m_mutex); if (GetIsDone()) @@ -998,27 +1023,13 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { goto exit_loop; case WAIT_OBJECT_0: { if (isConsole) { - while (true) { - INPUT_RECORD inputRecord; - DWORD numRead = 0; - if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) - goto exit_loop; - - // If the pipe is empty, go back to waiting on - // WaitForMultipleObjects rather than ReadFile. - if (numRead == 0) - goto read_loop; - - // We only care about text input. Consume all non text input events - // before letting ReadFile handle text input. - if (inputRecord.EventType == KEY_EVENT && - inputRecord.Event.KeyEvent.bKeyDown && - inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) - break; - - if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead)) - goto exit_loop; - } + auto hasInputOrErr = ConsoleHasTextInput(hStdin); + if (hasInputOrErr.takeError()) + goto exit_loop; + + // If no text input is ready, go back to waiting. + if (!*hasInputOrErr) + continue; } char ch = 0; @@ -1032,14 +1043,10 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { break; } case WAIT_OBJECT_0 + 1: { - char ch = 0; - DWORD read = 0; - if (!ReadFile(hInterrupt, &ch, 1, &read, nullptr) || read != 1) + ControlOp op = m_pending_op.exchange(eControlOpNone); + if (op == eControlOpQuit) goto exit_loop; - - if (ch == eControlOpQuit) - goto exit_loop; - if (ch == eControlOpInterrupt && + if (op == eControlOpInterrupt && StateIsRunningState(m_process->GetState())) m_process->SendAsyncInterrupt(); break; @@ -1057,18 +1064,16 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { std::lock_guard<std::mutex> guard(m_mutex); SetIsDone(true); if (m_is_running) { - char ch = eControlOpQuit; - if (llvm::Error err = m_pipe.Write(&ch, 1).takeError()) { - LLDB_LOG_ERROR(GetLog(LLDBLog::Process), std::move(err), - "Pipe write failed: {0}"); - } + m_pending_op.store(eControlOpQuit); + ::SetEvent(m_interrupt_event); } } bool Interrupt() override { if (m_active) { - char ch = eControlOpInterrupt; - return !errorToBool(m_pipe.Write(&ch, 1).takeError()); + m_pending_op.store(eControlOpInterrupt); + ::SetEvent(m_interrupt_event); + return true; } if (StateIsRunningState(m_process->GetState())) { m_process->SendAsyncInterrupt(); @@ -1080,19 +1085,21 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { void GotEOF() override {} private: - Process *m_process; - NativeFile m_read_file; // Read from this file (usually actual STDIN for LLDB - HANDLE m_write_file = - INVALID_HANDLE_VALUE; // Write to this file (usually the primary pty for - // getting io to debuggee) - Pipe m_pipe; - std::mutex m_mutex; - bool m_is_running = false; - enum ControlOp : char { eControlOpQuit = 'q', eControlOpInterrupt = 'i', + eControlOpNone = 0, }; + + Process *m_process; + /// Read from this file (usually actual STDIN for LLDB) + NativeFile m_read_file; + /// Write to this file (usually the primary pty for getting io to debuggee) + HANDLE m_write_file = INVALID_HANDLE_VALUE; + HANDLE m_interrupt_event = INVALID_HANDLE_VALUE; + std::atomic<ControlOp> m_pending_op{eControlOpNone}; + std::mutex m_mutex; + bool m_is_running = false; }; void ProcessWindows::SetPseudoConsoleHandle( >From ea41bc7ca9f2820182c262d856d5f14a4f281d93 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Tue, 20 Jan 2026 14:49:09 +0000 Subject: [PATCH 8/8] edit signature --- .../Plugins/Process/Windows/Common/ProcessWindows.cpp | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 50917fdb336b5..efaa893fc62d8 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -955,9 +955,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { IOHandler::Type::ProcessIO), m_process(process), m_read_file(GetInputFD(), File::eOpenOptionReadOnly, false), - m_write_file(conpty_input) { - m_interrupt_event = INVALID_HANDLE_VALUE; - } + m_write_file(conpty_input), m_interrupt_event(INVALID_HANDLE_VALUE) {} ~IOHandlerProcessSTDIOWindows() override = default; @@ -970,12 +968,12 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { /// Peek the console for input. If it has any, drain the pipe until text input /// is found or the pipe is empty. /// - /// \param[in, out] hStdin + /// \param hStdin /// The handle to the standard input's pipe. /// /// \return /// true if the pipe has text input. - llvm::Expected<bool> ConsoleHasTextInput(HANDLE hStdin) { + llvm::Expected<bool> ConsoleHasTextInput(const HANDLE hStdin) { while (true) { INPUT_RECORD inputRecord; DWORD numRead = 0; _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
