[lldb] Updated lldb-server to spawn the child process and share socket on Windows

`lldb-server platform --server` works on Windows now w/o multithreading. The rest functionality remains unchanged.

Added also PipeWindows::WriteWithTimeout(), fixed PipeWindows::ReadWithTimeout() and missing initialization of  m_read_overlapped.hEvent in the constructor PipeWindows(lldb::pipe_t read, lldb::pipe_t write).

Fixes #90923, fixes #56346.

This is the part 1 of the replacement of #100670.

In the part 2 I plan to switch `lldb-server gdbserver` to use `--fd` and listen a common gdb port for all gdbserver connections. Then we can remove gdb port mapping to fix #97537.

Author: slydiman

lldb/include/lldb/Host/windows/PipeWindows.h

@@ -61,6 +61,9 @@ class PipeWindows : public PipeBase {
   Status Delete(llvm::StringRef name) override;
 
   Status Write(const void *buf, size_t size, size_t &bytes_written) override;
+  Status WriteWithTimeout(const void *buf, size_t size,
+                          const std::chrono::microseconds &timeout,
+                          size_t &bytes_written);
   Status ReadWithTimeout(void *buf, size_t size,
                          const std::chrono::microseconds &timeout,
                          size_t &bytes_read) override;

lldb/source/Host/windows/PipeWindows.cpp

@@ -58,7 +58,10 @@ PipeWindows::PipeWindows(pipe_t read, pipe_t write)
   }
 
   ZeroMemory(&m_read_overlapped, sizeof(m_read_overlapped));
+  m_read_overlapped.hEvent = ::CreateEventA(nullptr, TRUE, FALSE, nullptr);
+
   ZeroMemory(&m_write_overlapped, sizeof(m_write_overlapped));
+  m_write_overlapped.hEvent = ::CreateEventA(nullptr, TRUE, FALSE, nullptr);
 }
 
 PipeWindows::~PipeWindows() { Close(); }
@@ -77,6 +80,7 @@ Status PipeWindows::CreateNew(bool child_process_inherit) {
 
   m_write_fd = _open_osfhandle((intptr_t)m_write, _O_WRONLY);
   ZeroMemory(&m_write_overlapped, sizeof(m_write_overlapped));
+  m_write_overlapped.hEvent = ::CreateEventA(nullptr, TRUE, FALSE, nullptr);
 
   return Status();
 }
@@ -202,6 +206,7 @@ Status PipeWindows::OpenNamedPipe(llvm::StringRef name,
     m_write_fd = _open_osfhandle((intptr_t)m_write, _O_WRONLY);
 
     ZeroMemory(&m_write_overlapped, sizeof(m_write_overlapped));
+    m_write_overlapped.hEvent = ::CreateEventA(nullptr, TRUE, FALSE, nullptr);
   }
 
   return Status();
@@ -228,6 +233,8 @@ int PipeWindows::ReleaseWriteFileDescriptor() {
     return PipeWindows::kInvalidDescriptor;
   int result = m_write_fd;
   m_write_fd = PipeWindows::kInvalidDescriptor;
+  if (m_write_overlapped.hEvent)
+    ::CloseHandle(m_write_overlapped.hEvent);
   m_write = INVALID_HANDLE_VALUE;
   ZeroMemory(&m_write_overlapped, sizeof(m_write_overlapped));
   return result;
@@ -250,6 +257,9 @@ void PipeWindows::CloseWriteFileDescriptor() {
   if (!CanWrite())
     return;
 
+  if (m_write_overlapped.hEvent)
+    ::CloseHandle(m_write_overlapped.hEvent);
+
   _close(m_write_fd);
   m_write = INVALID_HANDLE_VALUE;
   m_write_fd = PipeWindows::kInvalidDescriptor;
@@ -283,7 +293,12 @@ Status PipeWindows::ReadWithTimeout(void *buf, size_t size,
   DWORD sys_bytes_read = size;
   BOOL result = ::ReadFile(m_read, buf, sys_bytes_read, &sys_bytes_read,
                            &m_read_overlapped);
-  if (!result && GetLastError() != ERROR_IO_PENDING)
+  if (result) {
+    bytes_read = sys_bytes_read;
+    return Status();
+  }
+
+  if (GetLastError() != ERROR_IO_PENDING)
     return Status(::GetLastError(), eErrorTypeWin32);
 
   DWORD timeout = (duration == std::chrono::microseconds::zero())
@@ -319,18 +334,56 @@ Status PipeWindows::ReadWithTimeout(void *buf, size_t size,
 
 Status PipeWindows::Write(const void *buf, size_t num_bytes,
                           size_t &bytes_written) {
+  return WriteWithTimeout(buf, num_bytes, std::chrono::microseconds::zero(),
+                          bytes_written);
+}
+
+Status PipeWindows::WriteWithTimeout(const void *buf, size_t size,
+                                     const std::chrono::microseconds &duration,
+                                     size_t &bytes_written) {
   if (!CanWrite())
     return Status(ERROR_INVALID_HANDLE, eErrorTypeWin32);
 
-  DWORD sys_bytes_written = 0;
-  BOOL write_result = ::WriteFile(m_write, buf, num_bytes, &sys_bytes_written,
-                                  &m_write_overlapped);
-  if (!write_result && GetLastError() != ERROR_IO_PENDING)
+  bytes_written = 0;
+  DWORD sys_bytes_write = size;
+  BOOL result = ::WriteFile(m_write, buf, sys_bytes_write, &sys_bytes_write,
+                            &m_write_overlapped);
+  if (result) {
+    bytes_written = sys_bytes_write;
+    return Status();
+  }
+
+  if (GetLastError() != ERROR_IO_PENDING)
     return Status(::GetLastError(), eErrorTypeWin32);
 
-  BOOL result = GetOverlappedResult(m_write, &m_write_overlapped,
-                                    &sys_bytes_written, TRUE);
-  if (!result)
+  DWORD timeout = (duration == std::chrono::microseconds::zero())
+                      ? INFINITE
+                      : duration.count() * 1000;
+  DWORD wait_result = ::WaitForSingleObject(m_write_overlapped.hEvent, timeout);
+  if (wait_result != WAIT_OBJECT_0) {
+    // The operation probably failed.  However, if it timed out, we need to
+    // cancel the I/O. Between the time we returned from WaitForSingleObject
+    // and the time we call CancelIoEx, the operation may complete.  If that
+    // hapens, CancelIoEx will fail and return ERROR_NOT_FOUND. If that
+    // happens, the original operation should be considered to have been
+    // successful.
+    bool failed = true;
+    DWORD failure_error = ::GetLastError();
+    if (wait_result == WAIT_TIMEOUT) {
+      BOOL cancel_result = CancelIoEx(m_write, &m_write_overlapped);
+      if (!cancel_result && GetLastError() == ERROR_NOT_FOUND)
+        failed = false;
+    }
+    if (failed)
+      return Status(failure_error, eErrorTypeWin32);
+  }
+
+  // Now we call GetOverlappedResult setting bWait to false, since we've
+  // already waited as long as we're willing to.
+  if (!GetOverlappedResult(m_write, &m_write_overlapped, &sys_bytes_write,
+                           FALSE))
     return Status(::GetLastError(), eErrorTypeWin32);
+
+  bytes_written = sys_bytes_write;
   return Status();
 }

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerPlatform.cpp

@@ -159,6 +159,40 @@ GDBRemoteCommunicationServerPlatform::GDBRemoteCommunicationServerPlatform(
 GDBRemoteCommunicationServerPlatform::~GDBRemoteCommunicationServerPlatform() =
     default;
 
+void GDBRemoteCommunicationServerPlatform::Proc(
+    const lldb_private::Args &args) {
+  if (!IsConnected())
+    return;
+
+  if (args.GetArgumentCount() > 0) {
+    lldb::pid_t pid = LLDB_INVALID_PROCESS_ID;
+    std::optional<uint16_t> port;
+    std::string socket_name;
+    Status error = LaunchGDBServer(args,
+                                   "", // hostname
+                                   pid, port, socket_name);
+    if (error.Success())
+      SetPendingGdbServer(pid, *port, socket_name);
+  }
+
+  bool interrupt = false;
+  bool done = false;
+  Status error;
+  while (!interrupt && !done) {
+    if (GetPacketAndSendResponse(std::nullopt, error, interrupt, done) !=
+        GDBRemoteCommunication::PacketResult::Success)
+      break;
+  }
+
+  if (error.Fail()) {
+    Log *log = GetLog(LLDBLog::Platform);
+    LLDB_LOGF(log,
+              "GDBRemoteCommunicationServerPlatform::%s() "
+              "GetPacketAndSendResponse: %s",
+              __FUNCTION__, error.AsCString());
+  }
+}
+
 Status GDBRemoteCommunicationServerPlatform::LaunchGDBServer(
     const lldb_private::Args &args, std::string hostname, lldb::pid_t &pid,
     std::optional<uint16_t> &port, std::string &socket_name) {

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerPlatform.h

@@ -85,7 +85,7 @@ class GDBRemoteCommunicationServerPlatform
 
   void SetPortOffset(uint16_t port_offset);
 
-  void SetInferiorArguments(const lldb_private::Args &args);
+  void Proc(const lldb_private::Args &args);
 
   // Set port if you want to use a specific port number.
   // Otherwise port will be set to the port that was chosen for you.

lldb/tools/lldb-server/LLDBServerUtilities.cpp

@@ -27,11 +27,13 @@ class TestLogHandler : public LogHandler {
       : m_stream_sp(stream_sp) {}
 
   void Emit(llvm::StringRef message) override {
+    std::lock_guard<std::mutex> guard(m_mutex);
     (*m_stream_sp) << message;
     m_stream_sp->flush();
   }
 
 private:
+  std::mutex m_mutex;
   std::shared_ptr<raw_ostream> m_stream_sp;
 };