[lldb-dap] Add stdio redirection for integrated and external terminals (#161089)

This patch extends stdio redirection support to integrated and external
terminals. Currently, these cases are not covered by the standard logic
because `attach` is used instead of `launch`. To be honest,
`runInTerminal` in
[VSCode](https://github.com/microsoft/vscode/blob/main/src/vs/workbench/contrib/debug/node/terminals.ts#L188)
request supports `>` and `<` for redirection, but not `2>`. We could use
the `argsCanBeInterpretedByShell` option to use full power of shell,
however it requieres proper escaping of arguments on lldb-dap side. So,
I think it will be better to have the only one option to control stdio
redirection that works consistently across all console modes.

Also, fixed a small typo in a comparison that was leading to
out-of-bound access, and added `null` as a possible value for `stdio`
array in package.json.

Author: DrSergei

lldb/test/API/tools/lldb-dap/launch/TestDAP_launch.py

@@ -632,7 +632,27 @@ def test_stdio_redirection(self):
         program = self.getBuildArtifact("a.out")
 
         with tempfile.NamedTemporaryFile("rt") as f:
-            self.launch(program, stdio=[None, f.name, None])
+            self.launch(program, stdio=[None, f.name])
+            self.continue_to_exit()
+            lines = f.readlines()
+            self.assertIn(
+                program, lines[0], "make sure program path is in first argument"
+            )
+
+    @skipIfAsan
+    @skipIfWindows
+    @skipIf(oslist=["linux"], archs=no_match(["x86_64"]))
+    def test_stdio_redirection_and_console(self):
+        """
+        Test stdio redirection and console.
+        """
+        self.build_and_create_debug_adapter()
+        program = self.getBuildArtifact("a.out")
+
+        with tempfile.NamedTemporaryFile("rt") as f:
+            self.launch(
+                program, console="integratedTerminal", stdio=[None, f.name, None]
+            )
             self.continue_to_exit()
             lines = f.readlines()
             self.assertIn(

lldb/tools/lldb-dap/Handler/RequestHandler.cpp

@@ -57,7 +57,7 @@ SetupIORedirection(const std::vector<std::optional<std::string>> &stdio,
   size_t n = std::max(stdio.size(), static_cast<size_t>(3));
   for (size_t i = 0; i < n; i++) {
     std::optional<std::string> path;
-    if (stdio.size() < i)
+    if (stdio.size() <= i)
       path = stdio.back();
     else
       path = stdio[i];
@@ -107,7 +107,7 @@ RunInTerminal(DAP &dap, const protocol::LaunchRequestArguments &arguments) {
 
   llvm::json::Object reverse_request = CreateRunInTerminalReverseRequest(
       arguments.configuration.program, arguments.args, arguments.env,
-      arguments.cwd, comm_file.m_path, debugger_pid,
+      arguments.cwd, comm_file.m_path, debugger_pid, arguments.stdio,
       arguments.console == protocol::eConsoleExternalTerminal);
   dap.SendReverseRequest<LogFailureResponseHandler>("runInTerminal",
                                                     std::move(reverse_request));

lldb/tools/lldb-dap/JSONUtils.cpp

@@ -866,7 +866,8 @@ llvm::json::Value CreateCompileUnit(lldb::SBCompileUnit &unit) {
 llvm::json::Object CreateRunInTerminalReverseRequest(
     llvm::StringRef program, const std::vector<std::string> &args,
     const llvm::StringMap<std::string> &env, llvm::StringRef cwd,
-    llvm::StringRef comm_file, lldb::pid_t debugger_pid, bool external) {
+    llvm::StringRef comm_file, lldb::pid_t debugger_pid,
+    const std::vector<std::optional<std::string>> &stdio, bool external) {
   llvm::json::Object run_in_terminal_args;
   if (external) {
     // This indicates the IDE to open an external terminal window.
@@ -885,6 +886,18 @@ llvm::json::Object CreateRunInTerminalReverseRequest(
   }
   req_args.push_back("--launch-target");
   req_args.push_back(program.str());
+  if (!stdio.empty()) {
+    req_args.push_back("--stdio");
+    std::stringstream ss;
+    for (const std::optional<std::string> &file : stdio) {
+      if (file)
+        ss << *file;
+      ss << ":";
+    }
+    std::string files = ss.str();
+    files.pop_back();
+    req_args.push_back(std::move(files));
+  }
   req_args.insert(req_args.end(), args.begin(), args.end());
   run_in_terminal_args.try_emplace("args", req_args);
 

lldb/tools/lldb-dap/JSONUtils.h

@@ -388,6 +388,10 @@ llvm::json::Value CreateCompileUnit(lldb::SBCompileUnit &unit);
 ///     launcher uses it on Linux tell the kernel that it should allow the
 ///     debugger process to attach.
 ///
+/// \param[in] stdio
+///     An array of file paths for redirecting the program's standard IO
+///     streams.
+///
 /// \param[in] external
 ///     If set to true, the program will run in an external terminal window
 ///     instead of IDE's integrated terminal.
@@ -398,7 +402,8 @@ llvm::json::Value CreateCompileUnit(lldb::SBCompileUnit &unit);
 llvm::json::Object CreateRunInTerminalReverseRequest(
     llvm::StringRef program, const std::vector<std::string> &args,
     const llvm::StringMap<std::string> &env, llvm::StringRef cwd,
-    llvm::StringRef comm_file, lldb::pid_t debugger_pid, bool external);
+    llvm::StringRef comm_file, lldb::pid_t debugger_pid,
+    const std::vector<std::optional<std::string>> &stdio, bool external);
 
 /// Create a "Terminated" JSON object that contains statistics
 ///

lldb/tools/lldb-dap/Options.td

@@ -47,6 +47,12 @@ def debugger_pid: S<"debugger-pid">,
   HelpText<"The PID of the lldb-dap instance that sent the launchInTerminal "
     "request when using --launch-target.">;
 
+def stdio: S<"stdio">,
+  MetaVarName<"<stdin:stdout:stderr:...>">,
+  HelpText<"An array of file paths for redirecting the program's standard IO "
+    "streams. A colon-separated list of entries. Empty value means no "
+    "redirection.">;
+
 def repl_mode
     : S<"repl-mode">,
       MetaVarName<"<mode>">,

lldb/tools/lldb-dap/Protocol/ProtocolRequests.h

@@ -300,6 +300,7 @@ struct LaunchRequestArguments {
   /// terminal or external terminal.
   Console console = eConsoleInternal;
 
+  /// An array of file paths for redirecting the program's standard IO streams.
   std::vector<std::optional<std::string>> stdio;
 
   /// @}

lldb/tools/lldb-dap/package.json

@@ -626,7 +626,10 @@
               "stdio": {
                 "type": "array",
                 "items": {
-                  "type": "string"
+                  "type": [
+                    "string",
+                    "null"
+                  ]
                 },
                 "description": "The stdio property specifies the redirection targets for the debuggee's stdio streams. A null value redirects a stream to the default debug terminal. String can be a path to file, named pipe or TTY device. If less than three values are provided, the list will be padded with the last value. Specifying more than three values will create additional file descriptors (4, 5, etc.).",
                 "default": []

lldb/tools/lldb-dap/tool/lldb-dap.cpp

@@ -16,6 +16,7 @@
 #include "lldb/API/SBStream.h"
 #include "lldb/Host/Config.h"
 #include "lldb/Host/File.h"
+#include "lldb/Host/FileSystem.h"
 #include "lldb/Host/MainLoop.h"
 #include "lldb/Host/MainLoopBase.h"
 #include "lldb/Host/MemoryMonitor.h"
@@ -24,7 +25,9 @@
 #include "lldb/Utility/UriParser.h"
 #include "lldb/lldb-forward.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/ScopeExit.h"
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Option/Arg.h"
@@ -42,8 +45,10 @@
 #include "llvm/Support/WithColor.h"
 #include "llvm/Support/raw_ostream.h"
 #include <condition_variable>
+#include <cstddef>
 #include <cstdio>
 #include <cstdlib>
+#include <exception>
 #include <fcntl.h>
 #include <map>
 #include <memory>
@@ -143,6 +148,74 @@ static void PrintVersion() {
   llvm::outs() << "liblldb: " << lldb::SBDebugger::GetVersionString() << '\n';
 }
 
+#if not defined(_WIN32)
+struct FDGroup {
+  int GetFlags() const {
+    if (read && write)
+      return O_NOCTTY | O_CREAT | O_RDWR;
+    if (read)
+      return O_NOCTTY | O_RDONLY;
+    return O_NOCTTY | O_CREAT | O_WRONLY | O_TRUNC;
+  }
+
+  std::vector<int> fds;
+  bool read = false;
+  bool write = false;
+};
+
+static llvm::Error RedirectToFile(const FDGroup &fdg, llvm::StringRef file) {
+  if (!fdg.read && !fdg.write)
+    return llvm::Error::success();
+  int target_fd = lldb_private::FileSystem::Instance().Open(
+      file.str().c_str(), fdg.GetFlags(), 0666);
+  if (target_fd == -1)
+    return llvm::errorCodeToError(
+        std::error_code(errno, std::generic_category()));
+  for (int fd : fdg.fds) {
+    if (target_fd == fd)
+      continue;
+    if (::dup2(target_fd, fd) == -1)
+      return llvm::errorCodeToError(
+          std::error_code(errno, std::generic_category()));
+  }
+  ::close(target_fd);
+  return llvm::Error::success();
+}
+
+static llvm::Error
+SetupIORedirection(const llvm::SmallVectorImpl<llvm::StringRef> &files) {
+  llvm::SmallDenseMap<llvm::StringRef, FDGroup> groups;
+  for (size_t i = 0; i < files.size(); i++) {
+    if (files[i].empty())
+      continue;
+    auto group = groups.find(files[i]);
+    if (group == groups.end())
+      group = groups.insert({files[i], {{static_cast<int>(i)}}}).first;
+    else
+      group->second.fds.push_back(i);
+    switch (i) {
+    case 0:
+      group->second.read = true;
+      break;
+    case 1:
+    case 2:
+      group->second.write = true;
+      break;
+    default:
+      group->second.read = true;
+      group->second.write = true;
+      break;
+    }
+  }
+  for (const auto &[file, group] : groups) {
+    if (llvm::Error err = RedirectToFile(group, file))
+      return llvm::createStringError(
+          llvm::formatv("{0}: {1}", file, llvm::toString(std::move(err))));
+  }
+  return llvm::Error::success();
+}
+#endif
+
 // If --launch-target is provided, this instance of lldb-dap becomes a
 // runInTerminal launcher. It will ultimately launch the program specified in
 // the --launch-target argument, which is the original program the user wanted
@@ -165,6 +238,7 @@ static void PrintVersion() {
 static llvm::Error LaunchRunInTerminalTarget(llvm::opt::Arg &target_arg,
                                              llvm::StringRef comm_file,
                                              lldb::pid_t debugger_pid,
+                                             llvm::StringRef stdio,
                                              char *argv[]) {
 #if defined(_WIN32)
   return llvm::createStringError(
@@ -179,6 +253,16 @@ static llvm::Error LaunchRunInTerminalTarget(llvm::opt::Arg &target_arg,
     (void)prctl(PR_SET_PTRACER, debugger_pid, 0, 0, 0);
 #endif
 
+  lldb_private::FileSystem::Initialize();
+  if (!stdio.empty()) {
+    llvm::SmallVector<llvm::StringRef, 3> files;
+    stdio.split(files, ':');
+    while (files.size() < 3)
+      files.push_back(files.back());
+    if (llvm::Error err = SetupIORedirection(files))
+      return err;
+  }
+
   RunInTerminalLauncherCommChannel comm_channel(comm_file);
   if (llvm::Error err = comm_channel.NotifyPid())
     return err;
@@ -484,9 +568,10 @@ int main(int argc, char *argv[]) {
           break;
         }
       }
+      llvm::StringRef stdio = input_args.getLastArgValue(OPT_stdio);
       if (llvm::Error err =
               LaunchRunInTerminalTarget(*target_arg, comm_file->getValue(), pid,
-                                        argv + target_args_pos)) {
+                                        stdio, argv + target_args_pos)) {
         llvm::errs() << llvm::toString(std::move(err)) << '\n';
         return EXIT_FAILURE;
       }