Reapply "[lldb] Inherit DuplicateFileAction(HANDLE, HANDLE) handles on windows (#137978)" (#138896)

This reverts commit
https://github.com/llvm/llvm-project/commit/a0260a95ece74733ada00b19d8b1930dde462a66,
reapplying

https://github.com/llvm/llvm-project/commit/7c5f5f3ef83b1d1d43d63862a8431af3dded15bb,
with a fix that makes *both*
pipe handles inheritable.

The original commit description was:

This is a follow-up to https://github.com/llvm/llvm-project/pull/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).

1 files changed, 60 insertions, 13 deletions

diff --git a/lldb/source/Host/windows/ProcessLauncherWindows.cpp b/lldb/source/Host/windows/ProcessLauncherWindows.cpp
index 065ba9271ad0..bc35667ea9a2 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();