v2 uses PROC_THREAD_ATTRIBUTE_HANDLE_LIST for limiting fd

thanks @NVCherney for bring this to my attention.

include/boost/process/v2/stdio.hpp

@@ -303,12 +303,14 @@ struct process_stdio
 #if defined(BOOST_PROCESS_V2_WINDOWS)
   error_code on_setup(windows::default_launcher & launcher, const filesystem::path &, const std::wstring &)
   {
-
     launcher.startup_info.StartupInfo.dwFlags |= STARTF_USESTDHANDLES;
     launcher.startup_info.StartupInfo.hStdInput  = in.prepare();
     launcher.startup_info.StartupInfo.hStdOutput = out.prepare();
     launcher.startup_info.StartupInfo.hStdError  = err.prepare();
-    launcher.inherit_handles = true;
+    launcher.inherited_handles.reserve(launcher.inherited_handles.size() + 3);
+    launcher.inherited_handles.push_back(launcher.startup_info.StartupInfo.hStdInput);
+    launcher.inherited_handles.push_back(launcher.startup_info.StartupInfo.hStdOutput);
+    launcher.inherited_handles.push_back(launcher.startup_info.StartupInfo.hStdError);
     return error_code {};
   };
 #else

include/boost/process/v2/windows/as_user_launcher.hpp

@@ -91,13 +91,21 @@ struct as_user_launcher : default_launcher
       detail::on_error(*this, executable, command_line, ec, inits...);
       return basic_process<Executor>(exec);
     }
+
+    if (!inherited_handles.empty())
+    {
+      set_handle_list(ec);
+      if (ec)
+        return basic_process<Executor>(exec);
+    }
+
     auto ok = ::CreateProcessAsUserW(
         token,
         executable.empty() ? nullptr : executable.c_str(),
         command_line.empty() ? nullptr : &command_line.front(),
         process_attributes,
         thread_attributes,
-        inherit_handles ? TRUE : FALSE,
+        inherited_handles.empty() ? FALSE : TRUE,
         creation_flags,
         environment,
         current_directory.empty() ? nullptr : current_directory.c_str(),

include/boost/process/v2/windows/default_launcher.hpp

@@ -19,6 +19,8 @@
 #include <boost/process/v2/error.hpp>
 
 #include <numeric>
+#include <memory>
+#include <type_traits>
 #include <windows.h>
 
 #if defined(BOOST_PROCESS_V2_STANDALONE)
@@ -207,8 +209,8 @@ struct default_launcher
   SECURITY_ATTRIBUTES * process_attributes = nullptr;
   //// The thread_attributes passed to CreateProcess
   SECURITY_ATTRIBUTES * thread_attributes = nullptr;
-  /// The bInheritHandles option. Needs to be set to true by any initializers using handles.
-  bool inherit_handles = false;
+  /// The inhreited_handles option. bInheritHandles will be true if not empty..
+  std::vector<HANDLE> inherited_handles;
   /// The creation flags of the process. Initializers may add to them; extended startupinfo is assumed.
   DWORD creation_flags{EXTENDED_STARTUPINFO_PRESENT};
   /// A pointer to the subprocess environment.
@@ -294,18 +296,26 @@ struct default_launcher
     auto command_line = this->build_command_line(executable, std::forward<Args>(args));
 
     ec = detail::on_setup(*this, executable, command_line, inits...);
+
     if (ec)
     {
       detail::on_error(*this, executable, command_line, ec, inits...);
       return basic_process<Executor>(exec);
     }
 
+    if (!inherited_handles.empty())
+    {
+      set_handle_list(ec);
+      if (ec)
+        return basic_process<Executor>(exec);
+    }
+
     auto ok = ::CreateProcessW(
         executable.empty() ? nullptr : executable.c_str(),
         command_line.empty() ? nullptr : &command_line.front(),
         process_attributes,
         thread_attributes,
-        inherit_handles ? TRUE : FALSE,
+        inherited_handles.empty() ? FALSE : TRUE,
         creation_flags,
         environment,
         current_directory.empty() ? nullptr : current_directory.c_str(),
@@ -403,6 +413,18 @@ struct default_launcher
     return args;
   }
 
+  struct lpproc_thread_closer
+  {
+    void operator()(::LPPROC_THREAD_ATTRIBUTE_LIST l)
+    {
+      ::DeleteProcThreadAttributeList(l);
+      ::HeapFree(GetProcessHeap(), 0, l);
+    }
+  };
+  std::unique_ptr<std::remove_pointer<LPPROC_THREAD_ATTRIBUTE_LIST>::type, lpproc_thread_closer> proc_attribute_list_storage;
+
+  BOOST_PROCESS_V2_DECL LPPROC_THREAD_ATTRIBUTE_LIST get_thread_attribute_list(error_code & ec);
+  BOOST_PROCESS_V2_DECL void set_handle_list(error_code & ec);
 };
 
 

src/windows/default_launcher.cpp

@@ -75,6 +75,45 @@ namespace windows
     return itr - begin;
   }
 
+  LPPROC_THREAD_ATTRIBUTE_LIST default_launcher::get_thread_attribute_list(error_code & ec)
+  {
+    if (startup_info.lpAttributeList != nullptr)
+      return startup_info.lpAttributeList;
+    SIZE_T size;
+    if (!(::InitializeProcThreadAttributeList(NULL, 1, 0, &size) ||
+          GetLastError() == ERROR_INSUFFICIENT_BUFFER))
+    {
+      BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec);
+      return nullptr;
+    }
+
+    LPPROC_THREAD_ATTRIBUTE_LIST lpAttributeList = reinterpret_cast<LPPROC_THREAD_ATTRIBUTE_LIST>(::HeapAlloc(::GetProcessHeap(), 0, size));
+    if (lpAttributeList == nullptr)
+      return nullptr;
+
+    if (!::InitializeProcThreadAttributeList(lpAttributeList, 1, 0, &size))
+    {
+      BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec);
+      ::HeapFree(GetProcessHeap(), 0, lpAttributeList);
+      return nullptr;
+    }
+
+    proc_attribute_list_storage.reset(lpAttributeList);
+    startup_info.lpAttributeList = proc_attribute_list_storage.get();
+    return startup_info.lpAttributeList;
+  }
+
+  void default_launcher::set_handle_list(error_code & ec)
+  {
+    auto tl = get_thread_attribute_list(ec);
+    if (ec)
+      return;
+    if (!::UpdateProcThreadAttribute(
+        tl, 0, PROC_THREAD_ATTRIBUTE_HANDLE_LIST,
+        inherited_handles.data(), inherited_handles.size() * sizeof(HANDLE), nullptr, nullptr))
+      BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec);
+  }
+
 }
 BOOST_PROCESS_V2_END_NAMESPACE