[lldb-dap] Ensure the IO forwarding threads are managed by the DAP object lifecycle. (#120457)

This moves the ownership of the threads that forward stdout/stderr to
the DAP object itself to ensure that the threads are joined and that the
forwarding is cleaned up when the DAP connection is disconnected.

This is part of a larger refactor to allow lldb-dap to run in a
listening mode and accept multiple connections.

---------

Co-authored-by: Pavel Labath <pavel@labath.sk>

Author: ashgti

lldb/tools/lldb-dap/CMakeLists.txt

@@ -1,7 +1,3 @@
-if ( CMAKE_SYSTEM_NAME MATCHES "Windows" OR CMAKE_SYSTEM_NAME MATCHES "NetBSD" )
-  list(APPEND extra_libs lldbHost)
-endif ()
-
 if (HAVE_LIBPTHREAD)
   list(APPEND extra_libs pthread)
 endif ()
@@ -26,22 +22,23 @@ add_lldb_tool(lldb-dap
   lldb-dap.cpp
   Breakpoint.cpp
   BreakpointBase.cpp
+  DAP.cpp
   ExceptionBreakpoint.cpp
   FifoFiles.cpp
   FunctionBreakpoint.cpp
+  InstructionBreakpoint.cpp
   IOStream.cpp
   JSONUtils.cpp
   LLDBUtils.cpp
   OutputRedirector.cpp
   ProgressEvent.cpp
   RunInTerminal.cpp
   SourceBreakpoint.cpp
-  DAP.cpp
   Watchpoint.cpp
-  InstructionBreakpoint.cpp
 
   LINK_LIBS
     liblldb
+    lldbHost
     ${extra_libs}
 
   LINK_COMPONENTS

lldb/tools/lldb-dap/DAP.cpp

@@ -6,34 +6,62 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include <chrono>
-#include <cstdarg>
-#include <fstream>
-#include <mutex>
-
 #include "DAP.h"
 #include "JSONUtils.h"
 #include "LLDBUtils.h"
+#include "OutputRedirector.h"
+#include "lldb/API/SBBreakpoint.h"
 #include "lldb/API/SBCommandInterpreter.h"
+#include "lldb/API/SBCommandReturnObject.h"
 #include "lldb/API/SBLanguageRuntime.h"
 #include "lldb/API/SBListener.h"
+#include "lldb/API/SBProcess.h"
 #include "lldb/API/SBStream.h"
+#include "lldb/Host/FileSystem.h"
+#include "lldb/Utility/Status.h"
+#include "lldb/lldb-defines.h"
+#include "lldb/lldb-enumerations.h"
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FormatVariadic.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+#include <chrono>
+#include <cstdarg>
+#include <cstdio>
+#include <fstream>
+#include <mutex>
+#include <utility>
 
 #if defined(_WIN32)
 #define NOMINMAX
 #include <fcntl.h>
 #include <io.h>
 #include <windows.h>
+#else
+#include <unistd.h>
 #endif
 
 using namespace lldb_dap;
 
+namespace {
+#ifdef _WIN32
+const char DEV_NULL[] = "nul";
+#else
+const char DEV_NULL[] = "/dev/null";
+#endif
+} // namespace
+
 namespace lldb_dap {
 
-DAP::DAP(llvm::StringRef path, ReplMode repl_mode)
-    : debug_adaptor_path(path), broadcaster("lldb-dap"),
+DAP::DAP(llvm::StringRef path, std::ofstream *log, ReplMode repl_mode,
+         StreamDescriptor input, StreamDescriptor output)
+    : debug_adaptor_path(path), log(log), input(std::move(input)),
+      output(std::move(output)), broadcaster("lldb-dap"),
       exception_breakpoints(), focus_tid(LLDB_INVALID_THREAD_ID),
       stop_at_entry(false), is_attach(false),
       enable_auto_variable_summaries(false),
@@ -43,21 +71,7 @@ DAP::DAP(llvm::StringRef path, ReplMode repl_mode)
       configuration_done_sent(false), waiting_for_run_in_terminal(false),
       progress_event_reporter(
           [&](const ProgressEvent &event) { SendJSON(event.ToJSON()); }),
-      reverse_request_seq(0), repl_mode(repl_mode) {
-  const char *log_file_path = getenv("LLDBDAP_LOG");
-#if defined(_WIN32)
-  // Windows opens stdout and stdin in text mode which converts \n to 13,10
-  // while the value is just 10 on Darwin/Linux. Setting the file mode to binary
-  // fixes this.
-  int result = _setmode(fileno(stdout), _O_BINARY);
-  assert(result);
-  result = _setmode(fileno(stdin), _O_BINARY);
-  UNUSED_IF_ASSERT_DISABLED(result);
-  assert(result);
-#endif
-  if (log_file_path)
-    log.reset(new std::ofstream(log_file_path));
-}
+      reverse_request_seq(0), repl_mode(repl_mode) {}
 
 DAP::~DAP() = default;
 
@@ -173,6 +187,45 @@ ExceptionBreakpoint *DAP::GetExceptionBreakpoint(const lldb::break_id_t bp_id) {
   return nullptr;
 }
 
+llvm::Error DAP::ConfigureIO(std::FILE *overrideOut, std::FILE *overrideErr) {
+  in = lldb::SBFile(std::fopen(DEV_NULL, "r"), /*transfer_ownership=*/true);
+
+  if (auto Error = out.RedirectTo([this](llvm::StringRef output) {
+        SendOutput(OutputType::Stdout, output);
+      }))
+    return Error;
+
+  if (overrideOut) {
+    auto fd = out.GetWriteFileDescriptor();
+    if (auto Error = fd.takeError())
+      return Error;
+
+    if (dup2(*fd, fileno(overrideOut)) == -1)
+      return llvm::errorCodeToError(llvm::errnoAsErrorCode());
+  }
+
+  if (auto Error = err.RedirectTo([this](llvm::StringRef output) {
+        SendOutput(OutputType::Stderr, output);
+      }))
+    return Error;
+
+  if (overrideErr) {
+    auto fd = err.GetWriteFileDescriptor();
+    if (auto Error = fd.takeError())
+      return Error;
+
+    if (dup2(*fd, fileno(overrideErr)) == -1)
+      return llvm::errorCodeToError(llvm::errnoAsErrorCode());
+  }
+
+  return llvm::Error::success();
+}
+
+void DAP::StopIO() {
+  out.Stop();
+  err.Stop();
+}
+
 // Send the JSON in "json_str" to the "out" stream. Correctly send the
 // "Content-Length:" field followed by the length, followed by the raw
 // JSON bytes.
@@ -208,19 +261,19 @@ std::string DAP::ReadJSON() {
   std::string json_str;
   int length;
 
-  if (!input.read_expected(log.get(), "Content-Length: "))
+  if (!input.read_expected(log, "Content-Length: "))
     return json_str;
 
-  if (!input.read_line(log.get(), length_str))
+  if (!input.read_line(log, length_str))
     return json_str;
 
   if (!llvm::to_integer(length_str, length))
     return json_str;
 
-  if (!input.read_expected(log.get(), "\r\n"))
+  if (!input.read_expected(log, "\r\n"))
     return json_str;
 
-  if (!input.read_full(log.get(), length, json_str))
+  if (!input.read_full(log, length, json_str))
     return json_str;
 
   if (log) {

lldb/tools/lldb-dap/DAP.h

@@ -9,36 +9,38 @@
 #ifndef LLDB_TOOLS_LLDB_DAP_DAP_H
 #define LLDB_TOOLS_LLDB_DAP_DAP_H
 
-#include <cstdio>
-#include <iosfwd>
-#include <map>
-#include <optional>
-#include <thread>
-
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/DenseSet.h"
-#include "llvm/ADT/StringMap.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/Support/JSON.h"
-#include "llvm/Support/Threading.h"
-#include "llvm/Support/raw_ostream.h"
-
-#include "lldb/API/SBAttachInfo.h"
-#include "lldb/API/SBCommandInterpreter.h"
-#include "lldb/API/SBCommandReturnObject.h"
-#include "lldb/API/SBDebugger.h"
-#include "lldb/API/SBEvent.h"
-#include "lldb/API/SBFormat.h"
-#include "lldb/API/SBLaunchInfo.h"
-#include "lldb/API/SBTarget.h"
-#include "lldb/API/SBThread.h"
-
+#include "DAPForward.h"
 #include "ExceptionBreakpoint.h"
 #include "FunctionBreakpoint.h"
 #include "IOStream.h"
 #include "InstructionBreakpoint.h"
+#include "OutputRedirector.h"
 #include "ProgressEvent.h"
 #include "SourceBreakpoint.h"
+#include "lldb/API/SBBroadcaster.h"
+#include "lldb/API/SBCommandInterpreter.h"
+#include "lldb/API/SBDebugger.h"
+#include "lldb/API/SBError.h"
+#include "lldb/API/SBFile.h"
+#include "lldb/API/SBFormat.h"
+#include "lldb/API/SBFrame.h"
+#include "lldb/API/SBTarget.h"
+#include "lldb/API/SBThread.h"
+#include "lldb/API/SBValue.h"
+#include "lldb/API/SBValueList.h"
+#include "lldb/lldb-types.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/JSON.h"
+#include "llvm/Support/Threading.h"
+#include <map>
+#include <mutex>
+#include <optional>
+#include <thread>
+#include <vector>
 
 #define VARREF_LOCALS (int64_t)1
 #define VARREF_GLOBALS (int64_t)2
@@ -138,15 +140,18 @@ struct SendEventRequestHandler : public lldb::SBCommandPluginInterface {
 
 struct DAP {
   llvm::StringRef debug_adaptor_path;
+  std::ofstream *log;
   InputStream input;
   OutputStream output;
+  lldb::SBFile in;
+  OutputRedirector out;
+  OutputRedirector err;
   lldb::SBDebugger debugger;
   lldb::SBTarget target;
   Variables variables;
   lldb::SBBroadcaster broadcaster;
   std::thread event_thread;
   std::thread progress_event_thread;
-  std::unique_ptr<std::ofstream> log;
   llvm::StringMap<SourceBreakpointMap> source_breakpoints;
   FunctionBreakpointMap function_breakpoints;
   InstructionBreakpointMap instruction_breakpoints;
@@ -198,13 +203,23 @@ struct DAP {
   // will contain that expression.
   std::string last_nonempty_var_expression;
 
-  DAP(llvm::StringRef path, ReplMode repl_mode);
+  DAP(llvm::StringRef path, std::ofstream *log, ReplMode repl_mode,
+      StreamDescriptor input, StreamDescriptor output);
   ~DAP();
   DAP(const DAP &rhs) = delete;
   void operator=(const DAP &rhs) = delete;
   ExceptionBreakpoint *GetExceptionBreakpoint(const std::string &filter);
   ExceptionBreakpoint *GetExceptionBreakpoint(const lldb::break_id_t bp_id);
 
+  /// Redirect stdout and stderr fo the IDE's console output.
+  ///
+  /// Errors in this operation will be printed to the log file and the IDE's
+  /// console output as well.
+  llvm::Error ConfigureIO(std::FILE *overrideOut, std::FILE *overrideErr);
+
+  /// Stop the redirected IO threads and associated pipes.
+  void StopIO();
+
   // Serialize the JSON value into a string and send the JSON packet to
   // the "out" stream.
   void SendJSON(const llvm::json::Value &json);

lldb/tools/lldb-dap/IOStream.h

@@ -52,6 +52,9 @@ struct StreamDescriptor {
 struct InputStream {
   StreamDescriptor descriptor;
 
+  explicit InputStream(StreamDescriptor descriptor)
+      : descriptor(std::move(descriptor)) {}
+
   bool read_full(std::ofstream *log, size_t length, std::string &text);
 
   bool read_line(std::ofstream *log, std::string &line);
@@ -62,6 +65,9 @@ struct InputStream {
 struct OutputStream {
   StreamDescriptor descriptor;
 
+  explicit OutputStream(StreamDescriptor descriptor)
+      : descriptor(std::move(descriptor)) {}
+
   bool write_full(llvm::StringRef str);
 };
 } // namespace lldb_dap