[Lldb-commits] [lldb] [lldb] Inherit DuplicateFileAction(HANDLE, HANDLE) handles on windows (PR #137978)
Pavel Labath via lldb-commits
lldb-commits at lists.llvm.org
Wed May 7 02:21:48 PDT 2025
https://github.com/labath updated https://github.com/llvm/llvm-project/pull/137978
>From 4eb94714ec3c8249fbccb10c2cfd29f8c45b9a07 Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavel at labath.sk>
Date: Thu, 9 Jan 2025 15:32:11 +0100
Subject: [PATCH 1/2] [lldb] Inherit DuplicateFileAction(HANDLE, HANDLE)
handles on windows
This is a follow-up to #126935, which enables passing handles to a child
process on windows systems. Unlike on unix-like systems, the handles
need to be created with the "inheritable" flag because there's to way to
change the flag value after it has been created. This is why I don't
respect the child_process_inherit flag but rather always set the flag to
true. (My next step is to delete the flag entirely.)
This does mean that pipe may be created as inheritable even if its not
necessary, but I think this is offset by the fact that windows (unlike
unixes, which pass all ~O_CLOEXEC descriptors through execve and *all*
descriptors through fork) has a way to specify the precise set of
handles to pass to a specific child process.
If this turns out to be insufficient, instead of a constructor flag, I'd
rather go with creating a separate api to create an inheritable copy of
a handle (as typically, you only want to inherit one end of the pipe).
---
lldb/source/Host/windows/PipeWindows.cpp | 5 +-
.../Host/windows/ProcessLauncherWindows.cpp | 73 +++++++++++++++----
lldb/tools/lldb-server/lldb-platform.cpp | 2 -
lldb/unittests/Host/HostTest.cpp | 2 -
4 files changed, 63 insertions(+), 19 deletions(-)
diff --git a/lldb/source/Host/windows/PipeWindows.cpp b/lldb/source/Host/windows/PipeWindows.cpp
index e3f5b629a0590..1f7f6e03519d0 100644
--- a/lldb/source/Host/windows/PipeWindows.cpp
+++ b/lldb/source/Host/windows/PipeWindows.cpp
@@ -88,8 +88,9 @@ Status PipeWindows::CreateNew(llvm::StringRef name,
std::string pipe_path = g_pipe_name_prefix.str();
pipe_path.append(name.str());
- SECURITY_ATTRIBUTES sa{sizeof(SECURITY_ATTRIBUTES), 0,
- child_process_inherit ? TRUE : FALSE};
+ // We always create inheritable handles, but we won't pass them to a child
+ // process unless explicitly requested (cf. ProcessLauncherWindows.cpp).
+ SECURITY_ATTRIBUTES sa{sizeof(SECURITY_ATTRIBUTES), 0, TRUE};
// Always open for overlapped i/o. We implement blocking manually in Read
// and Write.
diff --git a/lldb/source/Host/windows/ProcessLauncherWindows.cpp b/lldb/source/Host/windows/ProcessLauncherWindows.cpp
index 065ba9271ad0d..bc35667ea9a23 100644
--- a/lldb/source/Host/windows/ProcessLauncherWindows.cpp
+++ b/lldb/source/Host/windows/ProcessLauncherWindows.cpp
@@ -10,6 +10,7 @@
#include "lldb/Host/HostProcess.h"
#include "lldb/Host/ProcessLaunchInfo.h"
+#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/ConvertUTF.h"
#include "llvm/Support/Program.h"
@@ -65,14 +66,23 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info,
std::string executable;
std::vector<char> environment;
- STARTUPINFO startupinfo = {};
+ STARTUPINFOEX startupinfoex = {};
+ STARTUPINFO &startupinfo = startupinfoex.StartupInfo;
PROCESS_INFORMATION pi = {};
HANDLE stdin_handle = GetStdioHandle(launch_info, STDIN_FILENO);
HANDLE stdout_handle = GetStdioHandle(launch_info, STDOUT_FILENO);
HANDLE stderr_handle = GetStdioHandle(launch_info, STDERR_FILENO);
-
- startupinfo.cb = sizeof(startupinfo);
+ auto close_handles = llvm::make_scope_exit([&] {
+ if (stdin_handle)
+ ::CloseHandle(stdin_handle);
+ if (stdout_handle)
+ ::CloseHandle(stdout_handle);
+ if (stderr_handle)
+ ::CloseHandle(stderr_handle);
+ });
+
+ startupinfo.cb = sizeof(startupinfoex);
startupinfo.dwFlags |= STARTF_USESTDHANDLES;
startupinfo.hStdError =
stderr_handle ? stderr_handle : ::GetStdHandle(STD_ERROR_HANDLE);
@@ -81,6 +91,48 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info,
startupinfo.hStdOutput =
stdout_handle ? stdout_handle : ::GetStdHandle(STD_OUTPUT_HANDLE);
+ std::vector<HANDLE> inherited_handles;
+ if (startupinfo.hStdError)
+ inherited_handles.push_back(startupinfo.hStdError);
+ if (startupinfo.hStdInput)
+ inherited_handles.push_back(startupinfo.hStdInput);
+ if (startupinfo.hStdOutput)
+ inherited_handles.push_back(startupinfo.hStdOutput);
+
+ size_t attributelist_size = 0;
+ InitializeProcThreadAttributeList(/*lpAttributeList=*/nullptr,
+ /*dwAttributeCount=*/1, /*dwFlags=*/0,
+ &attributelist_size);
+
+ startupinfoex.lpAttributeList =
+ static_cast<LPPROC_THREAD_ATTRIBUTE_LIST>(malloc(attributelist_size));
+ auto free_attributelist =
+ llvm::make_scope_exit([&] { free(startupinfoex.lpAttributeList); });
+ if (!InitializeProcThreadAttributeList(startupinfoex.lpAttributeList,
+ /*dwAttributeCount=*/1, /*dwFlags=*/0,
+ &attributelist_size)) {
+ error = Status(::GetLastError(), eErrorTypeWin32);
+ return HostProcess();
+ }
+ auto delete_attributelist = llvm::make_scope_exit(
+ [&] { DeleteProcThreadAttributeList(startupinfoex.lpAttributeList); });
+ for (size_t i = 0; i < launch_info.GetNumFileActions(); ++i) {
+ const FileAction *act = launch_info.GetFileActionAtIndex(i);
+ if (act->GetAction() == FileAction::eFileActionDuplicate &&
+ act->GetFD() == act->GetActionArgument())
+ inherited_handles.push_back(reinterpret_cast<HANDLE>(act->GetFD()));
+ }
+ if (!inherited_handles.empty()) {
+ if (!UpdateProcThreadAttribute(
+ startupinfoex.lpAttributeList, /*dwFlags=*/0,
+ PROC_THREAD_ATTRIBUTE_HANDLE_LIST, inherited_handles.data(),
+ inherited_handles.size() * sizeof(HANDLE),
+ /*lpPreviousValue=*/nullptr, /*lpReturnSize=*/nullptr)) {
+ error = Status(::GetLastError(), eErrorTypeWin32);
+ return HostProcess();
+ }
+ }
+
const char *hide_console_var =
getenv("LLDB_LAUNCH_INFERIORS_WITHOUT_CONSOLE");
if (hide_console_var &&
@@ -89,7 +141,8 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info,
startupinfo.wShowWindow = SW_HIDE;
}
- DWORD flags = CREATE_NEW_CONSOLE | CREATE_UNICODE_ENVIRONMENT;
+ DWORD flags = CREATE_NEW_CONSOLE | CREATE_UNICODE_ENVIRONMENT |
+ EXTENDED_STARTUPINFO_PRESENT;
if (launch_info.GetFlags().Test(eLaunchFlagDebug))
flags |= DEBUG_ONLY_THIS_PROCESS;
@@ -114,9 +167,10 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info,
WCHAR *pwcommandLine = wcommandLine.empty() ? nullptr : &wcommandLine[0];
BOOL result = ::CreateProcessW(
- wexecutable.c_str(), pwcommandLine, NULL, NULL, TRUE, flags, env_block,
+ wexecutable.c_str(), pwcommandLine, NULL, NULL,
+ /*bInheritHandles=*/!inherited_handles.empty(), flags, env_block,
wworkingDirectory.size() == 0 ? NULL : wworkingDirectory.c_str(),
- &startupinfo, &pi);
+ reinterpret_cast<STARTUPINFO *>(&startupinfoex), &pi);
if (!result) {
// Call GetLastError before we make any other system calls.
@@ -131,13 +185,6 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info,
::CloseHandle(pi.hThread);
}
- if (stdin_handle)
- ::CloseHandle(stdin_handle);
- if (stdout_handle)
- ::CloseHandle(stdout_handle);
- if (stderr_handle)
- ::CloseHandle(stderr_handle);
-
if (!result)
return HostProcess();
diff --git a/lldb/tools/lldb-server/lldb-platform.cpp b/lldb/tools/lldb-server/lldb-platform.cpp
index 10d79c63af994..5b0a8ade01025 100644
--- a/lldb/tools/lldb-server/lldb-platform.cpp
+++ b/lldb/tools/lldb-server/lldb-platform.cpp
@@ -274,10 +274,8 @@ static Status spawn_process(const char *progname, const FileSpec &prog,
self_args.AppendArgument(llvm::StringRef("platform"));
self_args.AppendArgument(llvm::StringRef("--child-platform-fd"));
self_args.AppendArgument(llvm::to_string(shared_socket.GetSendableFD()));
-#ifndef _WIN32
launch_info.AppendDuplicateFileAction((int)shared_socket.GetSendableFD(),
(int)shared_socket.GetSendableFD());
-#endif
if (gdb_port) {
self_args.AppendArgument(llvm::StringRef("--gdbserver-port"));
self_args.AppendArgument(llvm::to_string(gdb_port));
diff --git a/lldb/unittests/Host/HostTest.cpp b/lldb/unittests/Host/HostTest.cpp
index 222de62ab6697..9e4390a48fb18 100644
--- a/lldb/unittests/Host/HostTest.cpp
+++ b/lldb/unittests/Host/HostTest.cpp
@@ -90,7 +90,6 @@ TEST(Host, LaunchProcessSetsArgv0) {
ASSERT_THAT(exit_status.get_future().get(), 0);
}
-#ifdef LLVM_ON_UNIX
TEST(Host, LaunchProcessDuplicatesHandle) {
static constexpr llvm::StringLiteral test_msg("Hello subprocess!");
@@ -126,4 +125,3 @@ TEST(Host, LaunchProcessDuplicatesHandle) {
ASSERT_THAT_EXPECTED(bytes_read, llvm::Succeeded());
ASSERT_EQ(llvm::StringRef(msg, *bytes_read), test_msg);
}
-#endif
>From d6c7c4179c5775324dec01ca3a98117c856d94b6 Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavel at labath.sk>
Date: Wed, 7 May 2025 11:21:21 +0200
Subject: [PATCH 2/2] unifdef fd passing code
---
.../Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp | 2 --
1 file changed, 2 deletions(-)
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
index d8c7e436f3f8b..332b9255f226f 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -924,9 +924,7 @@ Status GDBRemoteCommunication::StartDebugserverProcess(
debugserver_args.AppendArgument(fd_arg.GetString());
// Send "pass_comm_fd" down to the inferior so it can use it to
// communicate back with this process. Ignored on Windows.
-#ifndef _WIN32
launch_info.AppendDuplicateFileAction((int)pass_comm_fd, (int)pass_comm_fd);
-#endif
}
// use native registers, not the GDB registers
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