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[lldb-dap] Add stdio redirection #158609

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Merged
merged 2 commits into from
Sep 16, 2025
Merged

[lldb-dap] Add stdio redirection #158609

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4c3e009
[lldb-dap] Add stdio redirection
DrSergei Sep 15, 2025
7bcc4ba
Fix review comments
DrSergei Sep 15, 2025
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3 changes: 3 additions & 0 deletions lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -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:
Expand Down
21 changes: 21 additions & 0 deletions lldb/test/API/tools/lldb-dap/launch/TestDAP_launch.py
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Expand Up @@ -6,6 +6,7 @@
from lldbsuite.test.lldbtest import *
import lldbdap_testcase
import os
import pathlib
import re
import tempfile

Expand Down Expand Up @@ -624,3 +625,23 @@ 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.
"""
temp_file = tempfile.NamedTemporaryFile().name
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Use this pattern

with tempfile.TemporaryFile() as fp:
  ...

that way you don't need to unlink the file manually

self.build_and_create_debug_adapter()
program = self.getBuildArtifact("a.out")

self.launch(program, stdio=[None, temp_file, None])
self.continue_to_exit()

try:
with open(temp_file, "r") as f:
lines = f.readlines()
self.assertIn(
program, lines[0], "make sure program path is in first argument"
)
finally:
pathlib.Path(temp_file).unlink(missing_ok=True)
25 changes: 25 additions & 0 deletions lldb/tools/lldb-dap/Handler/RequestHandler.cpp
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Expand Up @@ -177,6 +177,31 @@ llvm::Error BaseRequestHandler::LaunchProcess(
launch_info.SetEnvironment(env, true);
}

if (!arguments.stdio.empty() && !arguments.disableSTDIO) {
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Move this to a helper function because this function is already very big

size_t n = std::max(arguments.stdio.size(), static_cast<size_t>(3));
for (size_t i = 0; i < n; i++) {
std::optional<std::string> path;
if (arguments.stdio.size() < i)
path = arguments.stdio.back();
else
path = arguments.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;
}
}
}

launch_info.SetDetachOnError(arguments.detachOnError);
launch_info.SetShellExpandArguments(arguments.shellExpandArguments);

Expand Down
3 changes: 2 additions & 1 deletion lldb/tools/lldb-dap/Protocol/ProtocolRequests.cpp
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Expand Up @@ -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,
Expand Down
2 changes: 2 additions & 0 deletions lldb/tools/lldb-dap/Protocol/ProtocolRequests.h
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Expand Up @@ -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 &,
Expand Down
1 change: 1 addition & 0 deletions lldb/tools/lldb-dap/README.md
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Expand Up @@ -237,6 +237,7 @@ 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] | | Destination for program stdio streams (0 - stdin, 1 - stdout, 2 - stderr, ...). Using `null` value means no redirection. Supported from lldb-dap 22.0 version.
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Could you pretty much include all the contents from here

The stdio property is a list of redirection targets for each of the debuggee's stdio streams:

null value will cause redirect to the default debug session terminal (as specified by the terminal launch property),
"/some/path" will cause the stream to be redirected to the specified file, pipe or a TTY device*,
if you provide less than 3 values, the list will be padded to 3 entries using the last provided value,
you may specify more than three values, in which case additional file descriptors will be created (4, 5, etc.)
Examples:

"stdio": [null, "log.txt", null] - connect stdin and stderr to the default terminal, while sending stdout to "log.txt",
"stdio": ["input.txt", "log.txt"] - connect stdin to "input.txt", while sending both stdout and stderr to "log.txt",
"stdio": null - connect all three streams to the default terminal.

? That will be very clear

| **launchCommands** | [string] | | LLDB commands executed to launch the program.

For JSON configurations of `"type": "attach"`, the JSON configuration can contain
Expand Down
8 changes: 8 additions & 0 deletions lldb/tools/lldb-dap/package.json
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Expand Up @@ -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": "Destination for program stdio streams (0 - stdin, 1 - stdout, 2 - stderr, ...). Using null value means no redirection.",
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Same here about

The stdio property is a list of redirection targets for each of the debuggee's stdio streams:

null value will cause redirect to the default debug session terminal (as specified by the terminal launch property),
"/some/path" will cause the stream to be redirected to the specified file, pipe or a TTY device*,
if you provide less than 3 values, the list will be padded to 3 entries using the last provided value,
you may specify more than three values, in which case additional file descriptors will be created (4, 5, etc.)
Examples:

"stdio": [null, "log.txt", null] - connect stdin and stderr to the default terminal, while sending stdout to "log.txt",
"stdio": ["input.txt", "log.txt"] - connect stdin to "input.txt", while sending both stdout and stderr to "log.txt",
"stdio": null - connect all three streams to the default terminal.

"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."
Expand Down
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