[lldb-dap] Add stdio redirection (#158609)

As far as I understand, lldb-dap does not currently support stdio
redirection. I have added support for this via a new field in the launch
configuration named `stdio`. It was inspired by the same named field in
[CodeLLDB](https://github.com/vadimcn/codelldb/blob/master/MANUAL.md#stdio-redirection).

Author: DrSergei

lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py

@@ -1039,6 +1039,7 @@ def request_launch(
         disableSTDIO=False,
         shellExpandArguments=False,
         console: Optional[str] = None,
+        stdio: Optional[list[str]] = None,
         enableAutoVariableSummaries=False,
         displayExtendedBacktrace=False,
         enableSyntheticChildDebugging=False,
@@ -1090,6 +1091,8 @@ def request_launch(
             args_dict["sourceMap"] = sourceMap
         if console:
             args_dict["console"] = console
+        if stdio:
+            args_dict["stdio"] = stdio
         if postRunCommands:
             args_dict["postRunCommands"] = postRunCommands
         if customFrameFormat:

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

@@ -6,6 +6,7 @@
 from lldbsuite.test.lldbtest import *
 import lldbdap_testcase
 import os
+import pathlib
 import re
 import tempfile
 
@@ -625,3 +626,18 @@ def test_no_lldbinit_flag(self):
 
             # Verify the initCommands were executed
             self.verify_commands("initCommands", output, initCommands)
+
+    def test_stdio_redirection(self):
+        """
+        Test stdio redirection.
+        """
+        self.build_and_create_debug_adapter()
+        program = self.getBuildArtifact("a.out")
+
+        with tempfile.NamedTemporaryFile("rt") as f:
+            self.launch(program, stdio=[None, f.name, None])
+            self.continue_to_exit()
+            lines = f.readlines()
+            self.assertIn(
+                program, lines[0], "make sure program path is in first argument"
+            )

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

@@ -51,6 +51,33 @@ static uint32_t SetLaunchFlag(uint32_t flags, bool flag,
   return flags;
 }
 
+static void
+SetupIORedirection(const std::vector<std::optional<std::string>> &stdio,
+                   lldb::SBLaunchInfo &launch_info) {
+  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)
+      path = stdio.back();
+    else
+      path = stdio[i];
+    if (!path)
+      continue;
+    switch (i) {
+    case 0:
+      launch_info.AddOpenFileAction(i, path->c_str(), true, false);
+      break;
+    case 1:
+    case 2:
+      launch_info.AddOpenFileAction(i, path->c_str(), false, true);
+      break;
+    default:
+      launch_info.AddOpenFileAction(i, path->c_str(), true, true);
+      break;
+    }
+  }
+}
+
 static llvm::Error
 RunInTerminal(DAP &dap, const protocol::LaunchRequestArguments &arguments) {
   if (!dap.clientFeatures.contains(
@@ -177,6 +204,9 @@ llvm::Error BaseRequestHandler::LaunchProcess(
     launch_info.SetEnvironment(env, true);
   }
 
+  if (!arguments.stdio.empty() && !arguments.disableSTDIO)
+    SetupIORedirection(arguments.stdio, launch_info);
+
   launch_info.SetDetachOnError(arguments.detachOnError);
   launch_info.SetShellExpandArguments(arguments.shellExpandArguments);
 

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

@@ -303,7 +303,8 @@ bool fromJSON(const json::Value &Params, LaunchRequestArguments &LRA,
          O.mapOptional("disableSTDIO", LRA.disableSTDIO) &&
          O.mapOptional("shellExpandArguments", LRA.shellExpandArguments) &&
          O.mapOptional("runInTerminal", LRA.console) &&
-         O.mapOptional("console", LRA.console) && parseEnv(Params, LRA.env, P);
+         O.mapOptional("console", LRA.console) &&
+         O.mapOptional("stdio", LRA.stdio) && parseEnv(Params, LRA.env, P);
 }
 
 bool fromJSON(const json::Value &Params, AttachRequestArguments &ARA,

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

@@ -300,6 +300,8 @@ struct LaunchRequestArguments {
   /// terminal or external terminal.
   Console console = eConsoleInternal;
 
+  std::vector<std::optional<std::string>> stdio;
+
   /// @}
 };
 bool fromJSON(const llvm::json::Value &, LaunchRequestArguments &,

lldb/tools/lldb-dap/README.md

@@ -44,6 +44,34 @@ adds `FOO=1` and `bar` to the environment:
 }
 ```
 
+#### Launch in integrated terminal
+
+This will launch process in IDE's integrated terminal.
+
+```javascript
+{
+  "type": "lldb-dap",
+  "request": "launch",
+  "name": "Debug",
+  "program": "/tmp/a.out",
+  "console": "integratedTerminal"
+}
+```
+
+#### Setup IO redirection
+
+This will launch process and connect `stdin` to `in.txt`, both of `stdout` and `stderr` to `out.txt`.
+
+```javascript
+{
+  "type": "lldb-dap",
+  "request": "launch",
+  "name": "Debug",
+  "program": "/tmp/a.out",
+  "stdio": ["in.txt", "out.txt"]
+}
+```
+
 ### Attaching to a process
 
 When attaching to a process using LLDB, you can attach in multiple ways:
@@ -237,6 +265,7 @@ contain the following key/value pairs:
 | **stopOnEntry**                   | boolean     |     | Whether to stop program immediately after launching.
 | **runInTerminal** (deprecated)    | boolean     |     | Launch the program inside an integrated terminal in the IDE. Useful for debugging interactive command line programs.
 | **console**                       | string      |     | Specify where to launch the program: internal console (`internalConsole`), integrated terminal (`integratedTerminal`) or external terminal (`externalTerminal`). Supported from lldb-dap 21.0 version.
+| **stdio**                         | [string]    |     | 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.). Supported from lldb-dap 22.0 version.
 | **launchCommands**                | [string]    |     | LLDB commands executed to launch the program.
 
 For JSON configurations of `"type": "attach"`, the JSON configuration can contain

lldb/tools/lldb-dap/package.json

@@ -615,6 +615,14 @@
                 "description": "Specify where to launch the program: internal console, integrated terminal or external terminal.",
                 "default": "internalConsole"
               },
+              "stdio": {
+                "type": "array",
+                "items": {
+                  "type": "string"
+                },
+                "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": []
+              },
               "timeout": {
                 "type": "number",
                 "description": "The time in seconds to wait for a program to stop at entry point when launching with \"launchCommands\". Defaults to 30 seconds."