[lldb] Inherit DuplicateFileAction(HANDLE, HANDLE) handles on windows #137978
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@llvm/pr-subscribers-lldb Author: Pavel Labath (labath) ChangesThis is a follow-up to #126935, which enables passing handles to a child This does mean that pipe may be created as inheritable even if its not If this turns out to be insufficient, instead of a constructor flag, I'd Full diff: https://github.com/llvm/llvm-project/pull/137978.diff 6 Files Affected:
diff --git a/lldb/source/Host/macosx/objcxx/Host.mm b/lldb/source/Host/macosx/objcxx/Host.mm
index bb270f6a44e43..e187bf98188ae 100644
--- a/lldb/source/Host/macosx/objcxx/Host.mm
+++ b/lldb/source/Host/macosx/objcxx/Host.mm
@@ -1100,7 +1100,7 @@ static bool AddPosixSpawnFileAction(void *_file_actions, const FileAction *info,
else if (info->GetActionArgument() == -1)
error = Status::FromErrorString(
"invalid duplicate fd for posix_spawn_file_actions_adddup2(...)");
- else {
+ else if (info->GetFD() != info->GetActionArgument()) {
error =
Status(::posix_spawn_file_actions_adddup2(file_actions, info->GetFD(),
info->GetActionArgument()),
@@ -1110,6 +1110,15 @@ static bool AddPosixSpawnFileAction(void *_file_actions, const FileAction *info,
"error: {0}, posix_spawn_file_actions_adddup2 "
"(action={1}, fd={2}, dup_fd={3})",
error, file_actions, info->GetFD(), info->GetActionArgument());
+ } else {
+ error =
+ Status(::posix_spawn_file_actions_addinherit_np(file_actions, info->GetFD()),
+ eErrorTypePOSIX);
+ if (error.Fail())
+ LLDB_LOG(log,
+ "error: {0}, posix_spawn_file_actions_addinherit_np "
+ "(action={1}, fd={2})",
+ error, file_actions, info->GetFD());
}
break;
diff --git a/lldb/source/Host/posix/ProcessLauncherPosixFork.cpp b/lldb/source/Host/posix/ProcessLauncherPosixFork.cpp
index 8c6d503fc7fe2..698524349e16a 100644
--- a/lldb/source/Host/posix/ProcessLauncherPosixFork.cpp
+++ b/lldb/source/Host/posix/ProcessLauncherPosixFork.cpp
@@ -17,6 +17,7 @@
#include "llvm/Support/Errno.h"
#include <climits>
+#include <fcntl.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <unistd.h>
@@ -122,8 +123,14 @@ struct ForkLaunchInfo {
ExitWithError(error_fd, "close");
break;
case FileAction::eFileActionDuplicate:
- if (dup2(action.fd, action.arg) == -1)
- ExitWithError(error_fd, "dup2");
+ if (action.fd != action.arg) {
+ if (dup2(action.fd, action.arg) == -1)
+ ExitWithError(error_fd, "dup2");
+ } else {
+ if (fcntl(action.fd, F_SETFD,
+ fcntl(action.fd, F_GETFD) & ~FD_CLOEXEC) == -1)
+ ExitWithError(error_fd, "fcntl");
+ }
break;
case FileAction::eFileActionOpen:
DupDescriptor(error_fd, action.path.c_str(), action.fd, action.arg);
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 ed1df6de001ea..9e4390a48fb18 100644
--- a/lldb/unittests/Host/HostTest.cpp
+++ b/lldb/unittests/Host/HostTest.cpp
@@ -9,8 +9,10 @@
#include "lldb/Host/Host.h"
#include "TestingSupport/SubsystemRAII.h"
#include "lldb/Host/FileSystem.h"
+#include "lldb/Host/Pipe.h"
#include "lldb/Host/ProcessLaunchInfo.h"
#include "lldb/Utility/ProcessInfo.h"
+#include "llvm/ADT/Twine.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Testing/Support/Error.h"
@@ -87,3 +89,39 @@ TEST(Host, LaunchProcessSetsArgv0) {
ASSERT_THAT_ERROR(Host::LaunchProcess(info).takeError(), Succeeded());
ASSERT_THAT(exit_status.get_future().get(), 0);
}
+
+TEST(Host, LaunchProcessDuplicatesHandle) {
+ static constexpr llvm::StringLiteral test_msg("Hello subprocess!");
+
+ SubsystemRAII<FileSystem> subsystems;
+
+ if (test_arg) {
+ Pipe pipe(LLDB_INVALID_PIPE, (lldb::pipe_t)test_arg.getValue());
+ llvm::Expected<size_t> bytes_written =
+ pipe.Write(test_msg.data(), test_msg.size());
+ if (bytes_written && *bytes_written == test_msg.size())
+ exit(0);
+ exit(1);
+ }
+ Pipe pipe;
+ ASSERT_THAT_ERROR(pipe.CreateNew(/*child_process_inherit=*/false).takeError(),
+ llvm::Succeeded());
+ ProcessLaunchInfo info;
+ info.SetExecutableFile(FileSpec(TestMainArgv0),
+ /*add_exe_file_as_first_arg=*/true);
+ info.GetArguments().AppendArgument(
+ "--gtest_filter=Host.LaunchProcessDuplicatesHandle");
+ info.GetArguments().AppendArgument(
+ ("--test-arg=" + llvm::Twine((uint64_t)pipe.GetWritePipe())).str());
+ info.AppendDuplicateFileAction((uint64_t)pipe.GetWritePipe(),
+ (uint64_t)pipe.GetWritePipe());
+ info.SetMonitorProcessCallback(&ProcessLaunchInfo::NoOpMonitorCallback);
+ ASSERT_THAT_ERROR(Host::LaunchProcess(info).takeError(), llvm::Succeeded());
+ pipe.CloseWriteFileDescriptor();
+
+ char msg[100];
+ llvm::Expected<size_t> bytes_read =
+ pipe.Read(msg, sizeof(msg), std::chrono::seconds(10));
+ ASSERT_THAT_EXPECTED(bytes_read, llvm::Succeeded());
+ ASSERT_EQ(llvm::StringRef(msg, *bytes_read), test_msg);
+}
|
|
(Note this PR consists of two commits and the first commit is equivalent to #126935. For this PR, I recommend only viewing the second commit.) |
slydiman
reviewed
Apr 30, 2025
slydiman
reviewed
May 2, 2025
slydiman
approved these changes
May 5, 2025
This is a follow-up to llvm#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).
|
Probalby we can remove |
|
Thanks.
Indeed we should. In fact, that function is the reason I'm doing all this. :P |
|
(I see the failure on https://lab.llvm.org/buildbot/#/builders/197. I want to submit some additional logging code before I revert this.) |
labath
added a commit
to labath/llvm-project
that referenced
this pull request
May 7, 2025
…n windows (llvm#137978)" This reverts commit a0260a9, reapplying 7c5f5f3, with a fix that makes *both* pipe handles inheritable. The original commit description was: This is a follow-up to llvm#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).
labath
added a commit
that referenced
this pull request
May 12, 2025
…n windows (#137978)" (#138896) This reverts commit a0260a9, reapplying 7c5f5f3, with a fix that makes *both* pipe handles inheritable. The original commit description was: 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).
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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).