[Lldb-commits] [lldb] [lldb][Windows] add stdin support to lldb-server (PR #201638)
Charles Zablit via lldb-commits
lldb-commits at lists.llvm.org
Fri Jun 5 08:09:21 PDT 2026
https://github.com/charles-zablit updated https://github.com/llvm/llvm-project/pull/201638
>From 35d4db93b51d6eeb4c1f0c8c6c5bb27afc6adba4 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 4 Jun 2026 18:09:30 +0100
Subject: [PATCH 1/3] [lldb][Windows] add stdin support to lldb-server
---
.../lldb/Host/common/NativeProcessProtocol.h | 6 +-
.../Host/windows/ConnectionConPTYWindows.cpp | 27 ++-
.../Plugins/Process/Utility/CMakeLists.txt | 1 +
.../Utility/IOHandlerProcessSTDIOWindows.cpp | 172 ++++++++++++++++
.../Utility/IOHandlerProcessSTDIOWindows.h | 63 ++++++
.../Windows/Common/NativeProcessWindows.cpp | 15 ++
.../Windows/Common/NativeProcessWindows.h | 7 +
.../Process/Windows/Common/ProcessWindows.cpp | 190 +-----------------
.../Process/Windows/Common/ProcessWindows.h | 2 +
.../GDBRemoteCommunicationServerLLGS.cpp | 9 +-
.../Process/gdb-remote/ProcessGDBRemote.cpp | 16 +-
11 files changed, 325 insertions(+), 183 deletions(-)
create mode 100644 lldb/source/Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.cpp
create mode 100644 lldb/source/Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.h
diff --git a/lldb/include/lldb/Host/common/NativeProcessProtocol.h b/lldb/include/lldb/Host/common/NativeProcessProtocol.h
index 4e4804623b1d8..435185a38f3f9 100644
--- a/lldb/include/lldb/Host/common/NativeProcessProtocol.h
+++ b/lldb/include/lldb/Host/common/NativeProcessProtocol.h
@@ -247,8 +247,12 @@ class NativeProcessProtocol {
// Access to inferior stdio
virtual int GetTerminalFileDescriptor() { return m_terminal_fd; }
- // Stop id interface
+ /// Write up to \p len bytes from \p buf to the inferior's stdin.
+ virtual size_t WriteStdin(const void *buf, size_t len, Status &error) {
+ return 0;
+ }
+ // Stop id interface
uint32_t GetStopID() const;
// Callbacks for low-level process state changes
diff --git a/lldb/source/Host/windows/ConnectionConPTYWindows.cpp b/lldb/source/Host/windows/ConnectionConPTYWindows.cpp
index e9d026fc7dc9f..f7e90421653e3 100644
--- a/lldb/source/Host/windows/ConnectionConPTYWindows.cpp
+++ b/lldb/source/Host/windows/ConnectionConPTYWindows.cpp
@@ -61,5 +61,30 @@ size_t ConnectionConPTY::Read(void *dst, size_t dst_len,
size_t ConnectionConPTY::Write(const void *src, size_t src_len,
lldb::ConnectionStatus &status,
Status *error_ptr) {
- llvm_unreachable("not implemented");
+ if (!m_pty || !m_pty->IsConnected()) {
+ status = eConnectionStatusNoConnection;
+ if (error_ptr)
+ *error_ptr = Status::FromErrorString("ConPTY not connected");
+ return 0;
+ }
+ HANDLE stdin_handle = m_pty->GetSTDINHandle();
+ if (stdin_handle == INVALID_HANDLE_VALUE || stdin_handle == nullptr) {
+ status = eConnectionStatusNoConnection;
+ if (error_ptr)
+ *error_ptr = Status::FromErrorString("ConPTY STDIN handle is invalid");
+ return 0;
+ }
+ DWORD written = 0;
+ if (!::WriteFile(stdin_handle, src, static_cast<DWORD>(src_len), &written,
+ nullptr)) {
+ DWORD err = ::GetLastError();
+ status = (err == ERROR_BROKEN_PIPE || err == ERROR_NO_DATA)
+ ? eConnectionStatusEndOfFile
+ : eConnectionStatusError;
+ if (error_ptr)
+ *error_ptr = Status(err, lldb::eErrorTypeWin32);
+ return written;
+ }
+ status = eConnectionStatusSuccess;
+ return written;
}
diff --git a/lldb/source/Plugins/Process/Utility/CMakeLists.txt b/lldb/source/Plugins/Process/Utility/CMakeLists.txt
index 3652a0cfb530f..4206b398d982f 100644
--- a/lldb/source/Plugins/Process/Utility/CMakeLists.txt
+++ b/lldb/source/Plugins/Process/Utility/CMakeLists.txt
@@ -4,6 +4,7 @@ set_property(DIRECTORY PROPERTY LLDB_PLUGIN_KIND ProcessUtility)
add_lldb_library(lldbPluginProcessUtility
AuxVector.cpp
FreeBSDSignals.cpp
+ IOHandlerProcessSTDIOWindows.cpp
GDBRemoteSignals.cpp
HistoryThread.cpp
HistoryUnwind.cpp
diff --git a/lldb/source/Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.cpp b/lldb/source/Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.cpp
new file mode 100644
index 0000000000000..f8f5435fdbe07
--- /dev/null
+++ b/lldb/source/Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.cpp
@@ -0,0 +1,172 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "IOHandlerProcessSTDIOWindows.h"
+
+#include "lldb/Host/windows/windows.h"
+#include "lldb/Utility/LLDBLog.h"
+#include "lldb/Utility/Log.h"
+#include "lldb/Utility/State.h"
+
+using namespace lldb_private;
+
+IOHandlerProcessSTDIOWindows::IOHandlerProcessSTDIOWindows(Process *process)
+ : IOHandler(process->GetTarget().GetDebugger(), IOHandler::Type::ProcessIO),
+ m_process(process),
+ m_read_file(GetInputFD(), File::eOpenOptionReadOnly, false),
+ m_interrupt_event(
+ CreateEvent(/*lpEventAttributes=*/nullptr, /*bManualReset=*/FALSE,
+ /*bInitialState=*/FALSE, /*lpName=*/nullptr)) {}
+
+IOHandlerProcessSTDIOWindows::~IOHandlerProcessSTDIOWindows() {
+ if (m_interrupt_event != INVALID_HANDLE_VALUE)
+ ::CloseHandle(m_interrupt_event);
+}
+
+void IOHandlerProcessSTDIOWindows::SetIsRunning(bool running) {
+ std::lock_guard<std::mutex> guard(m_mutex);
+ SetIsDone(!running);
+ 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 hStdin
+/// The handle to the standard input's pipe.
+///
+/// \return
+/// true if the pipe has text input.
+llvm::Expected<bool>
+IOHandlerProcessSTDIOWindows::ConsoleHasTextInput(const HANDLE hStdin) {
+ // Check if there are already characters buffered. Pressing enter counts as
+ // 2 characters '\r\n' and only one of them is a keyDown event.
+ DWORD bytesAvailable = 0;
+ if (PeekNamedPipe(hStdin, nullptr, 0, nullptr, &bytesAvailable, nullptr)) {
+ if (bytesAvailable > 0)
+ return true;
+ }
+
+ 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 IOHandlerProcessSTDIOWindows::Run() {
+ if (!m_read_file.IsValid()) {
+ SetIsDone(true);
+ return;
+ }
+
+ SetIsDone(false);
+ SetIsRunning(true);
+
+ HANDLE hStdin = m_read_file.GetWaitableHandle();
+ HANDLE waitHandles[2] = {hStdin, m_interrupt_event};
+
+ DWORD consoleMode;
+ bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0;
+ // With ENABLE_LINE_INPUT, ReadFile returns only when a carriage return is
+ // read. This will block lldb in ReadFile until the user hits enter. Save
+ // the previous console mode to restore it later and remove
+ // ENABLE_LINE_INPUT.
+ DWORD oldConsoleMode = consoleMode;
+ SetConsoleMode(hStdin, consoleMode & ~ENABLE_LINE_INPUT & ~ENABLE_ECHO_INPUT);
+
+ while (true) {
+ {
+ std::lock_guard<std::mutex> guard(m_mutex);
+ if (GetIsDone())
+ goto exit_loop;
+ }
+
+ DWORD result = WaitForMultipleObjects(2, waitHandles, FALSE, INFINITE);
+ switch (result) {
+ case WAIT_FAILED:
+ goto exit_loop;
+ case WAIT_OBJECT_0: {
+ if (isConsole) {
+ auto hasInputOrErr = ConsoleHasTextInput(hStdin);
+ if (!hasInputOrErr) {
+ Log *log = GetLog(LLDBLog::Process);
+ LLDB_LOG_ERROR(log, hasInputOrErr.takeError(),
+ "failed to process debuggee's IO: {0}");
+ goto exit_loop;
+ }
+
+ // If no text input is ready, go back to waiting.
+ if (!*hasInputOrErr)
+ continue;
+ }
+
+ char ch = 0;
+ DWORD read = 0;
+ if (!ReadFile(hStdin, &ch, 1, &read, nullptr) || read != 1)
+ goto exit_loop;
+
+ Status err;
+ m_process->PutSTDIN(&ch, 1, err);
+ if (err.Fail())
+ goto exit_loop;
+ break;
+ }
+ case WAIT_OBJECT_0 + 1: {
+ ControlOp op = m_pending_op.exchange(eControlOpNone);
+ if (op == eControlOpQuit)
+ goto exit_loop;
+ if (op == eControlOpInterrupt &&
+ StateIsRunningState(m_process->GetState()))
+ m_process->SendAsyncInterrupt();
+ break;
+ }
+ default:
+ goto exit_loop;
+ }
+ }
+
+exit_loop:;
+ SetIsRunning(false);
+ SetIsDone(true);
+ SetConsoleMode(hStdin, oldConsoleMode);
+}
+
+void IOHandlerProcessSTDIOWindows::Cancel() {
+ std::lock_guard<std::mutex> guard(m_mutex);
+ SetIsDone(true);
+ if (m_is_running) {
+ m_pending_op.store(eControlOpQuit);
+ ::SetEvent(m_interrupt_event);
+ }
+}
+
+bool IOHandlerProcessSTDIOWindows::Interrupt() {
+ if (m_active) {
+ m_pending_op.store(eControlOpInterrupt);
+ ::SetEvent(m_interrupt_event);
+ return true;
+ }
+ if (StateIsRunningState(m_process->GetState())) {
+ m_process->SendAsyncInterrupt();
+ return true;
+ }
+ return false;
+}
\ No newline at end of file
diff --git a/lldb/source/Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.h b/lldb/source/Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.h
new file mode 100644
index 0000000000000..fcbd587b40143
--- /dev/null
+++ b/lldb/source/Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.h
@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LIBLLDB_PLUGINS_PROCESS_WINDOWS_COMMON_IO_HANDLER_PROCESS_STDIO_WINDOWS_H_
+#define LIBLLDB_PLUGINS_PROCESS_WINDOWS_COMMON_IO_HANDLER_PROCESS_STDIO_WINDOWS_H_
+
+#include "lldb/Core/IOHandler.h"
+#include "lldb/Host/File.h"
+#include "lldb/Target/Process.h"
+
+typedef void *HANDLE;
+
+using namespace lldb_private;
+
+class IOHandlerProcessSTDIOWindows : public IOHandler {
+public:
+ IOHandlerProcessSTDIOWindows(Process *process);
+
+ ~IOHandlerProcessSTDIOWindows() override;
+
+ void SetIsRunning(bool running);
+
+ /// Peek the console for input. If it has any, drain the pipe until text input
+ /// is found or the pipe is empty.
+ ///
+ /// \param hStdin
+ /// The handle to the standard input's pipe.
+ ///
+ /// \return
+ /// true if the pipe has text input.
+ llvm::Expected<bool> ConsoleHasTextInput(const HANDLE hStdin);
+
+ void Run() override;
+
+ void Cancel() override;
+
+ bool Interrupt() override;
+
+ void GotEOF() override {}
+
+private:
+ 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;
+ HANDLE m_interrupt_event =
+ reinterpret_cast<HANDLE>(static_cast<intptr_t>(-1));
+ std::atomic<ControlOp> m_pending_op{eControlOpNone};
+ std::mutex m_mutex;
+ bool m_is_running = false;
+};
+
+#endif // LIBLLDB_PLUGINS_PROCESS_WINDOWS_COMMON_IO_HANDLER_PROCESS_STDIO_WINDOWS_H_
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
index b235ab281bad6..bf447c9ea81f5 100644
--- a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
@@ -749,4 +749,19 @@ void NativeProcessWindows::STDIOReadThreadBytesReceived(void *baton,
self->m_delegate.NewProcessOutput(
self, llvm::StringRef(static_cast<const char *>(src), src_len));
}
+
+size_t NativeProcessWindows::WriteStdin(const void *buf, size_t len,
+ Status &error) {
+ if (!m_stdio_communication.HasConnection()) {
+ error = Status::FromErrorString(
+ "no ConPTY connection on this NativeProcessWindows");
+ return 0;
+ }
+ ConnectionStatus status;
+ size_t written = m_stdio_communication.Write(buf, len, status, &error);
+ if (status != eConnectionStatusSuccess && error.Success())
+ error = Status::FromErrorStringWithFormatv(
+ "ConPTY stdin write returned status {0}", static_cast<int>(status));
+ return written;
+}
} // namespace lldb_private
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
index 95b85754ebdeb..cac3920d82aa9 100644
--- a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
@@ -107,6 +107,13 @@ class NativeProcessWindows : public NativeProcessProtocol,
bool HasPendingLibraryEvents() override;
+ /// Forward bytes from the gdb-remote `I` packet into the inferior's
+ /// ConPTY-backed stdin via `m_stdio_communication.Write` →
+ /// `ConnectionConPTY::Write` → `WriteFile` on the parent-side STDIN
+ /// HANDLE. Returns the number of bytes written (0 if the PTY is
+ /// disconnected or write fails).
+ size_t WriteStdin(const void *buf, size_t len, Status &error) override;
+
// ProcessDebugger Overrides
void OnExitProcess(uint32_t exit_code) override;
void OnDebuggerConnected(lldb::addr_t image_base) override;
diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
index 9a273463792ce..83d9e784f75a0 100644
--- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
@@ -45,6 +45,7 @@
#include "ExceptionRecord.h"
#include "ForwardDecl.h"
#include "LocalDebugDelegate.h"
+#include "Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.h"
#include "ProcessWindowsLog.h"
#include "TargetThreadWindows.h"
@@ -1084,184 +1085,15 @@ Status ProcessWindows::DisableWatchpoint(WatchpointSP wp_sp, bool notify) {
return error;
}
-class IOHandlerProcessSTDIOWindows : public IOHandler {
-public:
- IOHandlerProcessSTDIOWindows(Process *process, HANDLE conpty_input)
- : IOHandler(process->GetTarget().GetDebugger(),
- IOHandler::Type::ProcessIO),
- m_process(process),
- m_read_file(GetInputFD(), File::eOpenOptionReadOnly, false),
- m_write_file(conpty_input),
- m_interrupt_event(
- CreateEvent(/*lpEventAttributes=*/nullptr, /*bManualReset=*/FALSE,
- /*bInitialState=*/FALSE, /*lpName=*/nullptr)) {}
-
- ~IOHandlerProcessSTDIOWindows() override {
- if (m_interrupt_event != INVALID_HANDLE_VALUE)
- ::CloseHandle(m_interrupt_event);
+size_t ProcessWindows::PutSTDIN(const char *src, size_t src_len,
+ Status &error) {
+ if (!m_stdio_communication.IsConnected()) {
+ error = Status::FromErrorString("stdin not connected");
+ return 0;
}
-
- void SetIsRunning(bool running) {
- std::lock_guard<std::mutex> guard(m_mutex);
- SetIsDone(!running);
- 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 hStdin
- /// The handle to the standard input's pipe.
- ///
- /// \return
- /// true if the pipe has text input.
- llvm::Expected<bool> ConsoleHasTextInput(const HANDLE hStdin) {
- // Check if there are already characters buffered. Pressing enter counts as
- // 2 characters '\r\n' and only one of them is a keyDown event.
- DWORD bytesAvailable = 0;
- if (PeekNamedPipe(hStdin, nullptr, 0, nullptr, &bytesAvailable, nullptr)) {
- if (bytesAvailable > 0)
- return true;
- }
-
- 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) {
- SetIsDone(true);
- return;
- }
-
- SetIsDone(false);
- SetIsRunning(true);
-
- HANDLE hStdin = m_read_file.GetWaitableHandle();
- HANDLE waitHandles[2] = {hStdin, m_interrupt_event};
-
- DWORD consoleMode;
- bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0;
- // With ENABLE_LINE_INPUT, ReadFile returns only when a carriage return is
- // read. This will block lldb in ReadFile until the user hits enter. Save
- // the previous console mode to restore it later and remove
- // ENABLE_LINE_INPUT.
- DWORD oldConsoleMode = consoleMode;
- SetConsoleMode(hStdin,
- consoleMode & ~ENABLE_LINE_INPUT & ~ENABLE_ECHO_INPUT);
-
- while (true) {
- {
- std::lock_guard<std::mutex> guard(m_mutex);
- if (GetIsDone())
- goto exit_loop;
- }
-
- DWORD result = WaitForMultipleObjects(2, waitHandles, FALSE, INFINITE);
- switch (result) {
- case WAIT_FAILED:
- goto exit_loop;
- case WAIT_OBJECT_0: {
- if (isConsole) {
- auto hasInputOrErr = ConsoleHasTextInput(hStdin);
- if (!hasInputOrErr) {
- Log *log = GetLog(WindowsLog::Process);
- LLDB_LOG_ERROR(log, hasInputOrErr.takeError(),
- "failed to process debuggee's IO: {0}");
- goto exit_loop;
- }
-
- // If no text input is ready, go back to waiting.
- if (!*hasInputOrErr)
- continue;
- }
-
- char ch = 0;
- DWORD read = 0;
- if (!ReadFile(hStdin, &ch, 1, &read, nullptr) || read != 1)
- goto exit_loop;
-
- DWORD written = 0;
- if (!WriteFile(m_write_file, &ch, 1, &written, nullptr) || written != 1)
- goto exit_loop;
- break;
- }
- case WAIT_OBJECT_0 + 1: {
- ControlOp op = m_pending_op.exchange(eControlOpNone);
- if (op == eControlOpQuit)
- goto exit_loop;
- if (op == eControlOpInterrupt &&
- StateIsRunningState(m_process->GetState()))
- m_process->SendAsyncInterrupt();
- break;
- }
- default:
- goto exit_loop;
- }
- }
-
- exit_loop:;
- SetIsRunning(false);
- SetIsDone(true);
- SetConsoleMode(hStdin, oldConsoleMode);
- }
-
- void Cancel() override {
- std::lock_guard<std::mutex> guard(m_mutex);
- SetIsDone(true);
- if (m_is_running) {
- m_pending_op.store(eControlOpQuit);
- ::SetEvent(m_interrupt_event);
- }
- }
-
- bool Interrupt() override {
- if (m_active) {
- m_pending_op.store(eControlOpInterrupt);
- ::SetEvent(m_interrupt_event);
- return true;
- }
- if (StateIsRunningState(m_process->GetState())) {
- m_process->SendAsyncInterrupt();
- return true;
- }
- return false;
- }
-
- void GotEOF() override {}
-
-private:
- 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;
-};
+ ConnectionStatus status;
+ return m_stdio_communication.WriteAll(src, src_len, status, &error);
+}
void ProcessWindows::SetPseudoConsoleHandle() {
if (m_pty == nullptr)
@@ -1277,8 +1109,8 @@ void ProcessWindows::SetPseudoConsoleHandle() {
{
std::lock_guard<std::mutex> guard(m_process_input_reader_mutex);
if (!m_process_input_reader)
- m_process_input_reader = std::make_shared<IOHandlerProcessSTDIOWindows>(
- this, m_pty->GetSTDINHandle());
+ m_process_input_reader =
+ std::make_shared<IOHandlerProcessSTDIOWindows>(this);
}
}
}
diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.h b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.h
index da35ae923dcee..38c47a95e6cbf 100644
--- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.h
+++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.h
@@ -113,6 +113,8 @@ class ProcessWindows : public Process, public ProcessDebugger {
/// buffered in the ConPTY/pipe to the process's STDOUT cache.
void DrainProcessStdout();
+ size_t PutSTDIN(const char *src, size_t src_len, Status &error);
+
ProcessWindows(lldb::TargetSP target_sp, lldb::ListenerSP listener_sp);
Status DoGetMemoryRegionInfo(lldb::addr_t vm_addr,
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
index d56026e011564..077144f94227d 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -2569,12 +2569,19 @@ GDBRemoteCommunicationServerLLGS::Handle_I(StringExtractorGDBRemote &packet) {
// write directly to stdin *this might block if stdin buffer is full*
// TODO: enqueue this block in circular buffer and send window size to
// remote host
- ConnectionStatus status;
Status error;
+
+#if defined(_WIN32)
+ // On Windows the inferior's stdio is owned by NativeProcessWindows.
+ if (m_current_process->WriteStdin(tmp, read, error) != read || error.Fail())
+ return SendErrorResponse(0x15);
+#else
+ ConnectionStatus status;
m_stdio_communication.WriteAll(tmp, read, status, &error);
if (error.Fail()) {
return SendErrorResponse(0x15);
}
+#endif
}
return SendOKResponse();
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index f6eaf5851338b..c6573499ff3d6 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -95,6 +95,10 @@
#include "llvm/Support/Threading.h"
#include "llvm/Support/raw_ostream.h"
+#ifdef _WIN32
+#include "Plugins/Process/Utility/IOHandlerProcessSTDIOWindows.h"
+#endif
+
#if defined(__APPLE__)
#define DEBUGSERVER_BASENAME "debugserver"
#elif defined(_WIN32)
@@ -873,8 +877,18 @@ Status ProcessGDBRemote::DoLaunch(lldb_private::Module *exe_module,
SetPrivateState(SetThreadStopInfo(response));
if (!disable_stdio) {
- if (pty.GetPrimaryFileDescriptor() != PseudoTerminal::invalid_fd)
+ if (pty.GetPrimaryFileDescriptor() != PseudoTerminal::invalid_fd) {
SetSTDIOFileDescriptor(pty.ReleasePrimaryFileDescriptor());
+ }
+#ifdef _WIN32
+ else if (m_stdin_forward) {
+ // No client-side PTY FD on Windows.
+ std::lock_guard<std::mutex> guard(m_process_input_reader_mutex);
+ if (!m_process_input_reader)
+ m_process_input_reader =
+ std::make_shared<IOHandlerProcessSTDIOWindows>(this);
+ }
+#endif
}
}
} else {
>From 24cdb004703724e62e4960937eca0bd4c7e3dda8 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 4 Jun 2026 18:10:57 +0100
Subject: [PATCH 2/3] [lldb][gdb-remote] Plumb interrupt_timeout through
SendStdinNotification
---
.../Process/gdb-remote/GDBRemoteCommunicationClient.cpp | 7 ++++---
.../Process/gdb-remote/GDBRemoteCommunicationClient.h | 9 ++++++++-
.../Plugins/Process/gdb-remote/ProcessGDBRemote.cpp | 2 +-
3 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index 8df7936786b04..3a69a1d21f906 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1442,13 +1442,14 @@ bool GDBRemoteCommunicationClient::GetHostInfo(bool force) {
return m_qHostInfo_is_valid == eLazyBoolYes;
}
-int GDBRemoteCommunicationClient::SendStdinNotification(const char *data,
- size_t data_len) {
+int GDBRemoteCommunicationClient::SendStdinNotification(
+ const char *data, size_t data_len, std::chrono::seconds interrupt_timeout) {
StreamString packet;
packet.PutCString("I");
packet.PutBytesAsRawHex8(data, data_len);
StringExtractorGDBRemote response;
- if (SendPacketAndWaitForResponse(packet.GetString(), response) ==
+ if (SendPacketAndWaitForResponse(packet.GetString(), response,
+ interrupt_timeout) ==
PacketResult::Success) {
return 0;
}
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
index 79ca0bcd3ed22..384a7da4d06e4 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
@@ -127,10 +127,17 @@ class GDBRemoteCommunicationClient : public GDBRemoteClientBase {
/// \param[in] data_len
/// The number of bytes available at \a data.
///
+ /// \param[in] interrupt_timeout
+ /// If the inferior is running, how long to wait for a `\x03` BREAK
+ /// to interrupt it before giving up. Pass zero (the default) only
+ /// when the caller knows the inferior is stopped.
+ ///
/// \return
/// Zero if the attach was successful, or an error indicating
/// an error code.
- int SendStdinNotification(const char *data, size_t data_len);
+ int SendStdinNotification(
+ const char *data, size_t data_len,
+ std::chrono::seconds interrupt_timeout = std::chrono::seconds(0));
/// Sets the path to use for stdin/out/err for a process
/// that will be launched with the 'A' packet.
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index c6573499ff3d6..0319c3606362a 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -3352,7 +3352,7 @@ size_t ProcessGDBRemote::PutSTDIN(const char *src, size_t src_len,
ConnectionStatus status;
m_stdio_communication.WriteAll(src, src_len, status, nullptr);
} else if (m_stdin_forward) {
- m_gdb_comm.SendStdinNotification(src, src_len);
+ m_gdb_comm.SendStdinNotification(src, src_len, GetInterruptTimeout());
}
return 0;
}
>From 540a72bc597eca7827c48522e8e67cec3b0b46a5 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 4 Jun 2026 18:12:21 +0100
Subject: [PATCH 3/3] [lldb][Windows] Surface DebugBreakProcess Halt() as a
SIGSTOP signal stop
---
.../Windows/Common/NativeProcessWindows.cpp | 36 +++++++++++++++++--
.../Windows/Common/NativeProcessWindows.h | 3 ++
2 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
index bf447c9ea81f5..f0dc855457ac9 100644
--- a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
@@ -173,8 +173,13 @@ NativeProcessWindows::GetThreadByID(lldb::tid_t thread_id) {
Status NativeProcessWindows::Halt() {
bool caused_stop = false;
StateType state = GetState();
- if (state != eStateStopped)
- return HaltProcess(caused_stop);
+ if (state != eStateStopped) {
+ m_pending_halt = true;
+ Status err = HaltProcess(caused_stop);
+ if (err.Fail() || !caused_stop)
+ m_pending_halt = false;
+ return err;
+ }
return Status();
}
@@ -581,6 +586,33 @@ NativeProcessWindows::HandleBreakpointException(const ExceptionRecord &record) {
// Any remaining STATUS_BREAKPOINT is a breakpoint instruction in the
// program's own code (e.g. `__debugbreak()` or `__builtin_debugtrap()`).
// Stop the debugger and let the user decide what to do.
+ if (m_pending_halt) {
+ LLDB_LOG(log,
+ "DebugBreakProcess injection treated as Halt SIGSTOP for tid "
+ "{0:x}",
+ thread_id);
+ m_pending_halt = false;
+ ThreadStopInfo signal_info;
+ signal_info.reason = StopReason::eStopReasonSignal;
+ signal_info.signo = 19; // SIGSTOP on POSIX
+
+ // Halt all threads at the kernel level.
+ for (uint32_t i = 0; i < m_threads.size(); ++i) {
+ auto t = static_cast<NativeThreadWindows *>(m_threads[i].get());
+ if (t->DoStop().Fail())
+ exit(1);
+ }
+ if (!m_threads.empty()) {
+ auto first = static_cast<NativeThreadWindows *>(m_threads[0].get());
+ first->SetStopReason(signal_info, "interrupt");
+ }
+ SetCurrentThreadID(thread_id);
+ if (NativeThreadWindows *injected = GetThreadByID(thread_id))
+ injected->SetStopReason(signal_info, "interrupt");
+ SetState(eStateStopped, true);
+ return ExceptionResult::BreakInDebugger;
+ }
+
std::string desc = formatv("Exception {0:x8} encountered at address {1:x8}",
record.GetExceptionCode(), exception_addr)
.str();
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
index cac3920d82aa9..d1c57fc01e06b 100644
--- a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
@@ -167,6 +167,9 @@ class NativeProcessWindows : public NativeProcessProtocol,
/// launch / attach.
bool m_initial_stop_seen = false;
+ /// Set when Halt() / Interrupt() schedules a DebugBreakProcess injection.
+ bool m_pending_halt = false;
+
/// PseudoConsole for the lldb-server stdio-forwarding path.
std::shared_ptr<PseudoConsole> m_pty;
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