From f796ee9e650d5f73844f862ed51a6de6bb33c219 Mon Sep 17 00:00:00 2001
From: Stefan Boberg <stefan.boberg@epicgames.com>
Date: Sat, 28 Feb 2026 15:36:50 +0100
Subject: subprocess tracking using Jobs on Windows/hub (#796)

This change introduces job object support on Windows to be able to more accurately track and limit resource usage on storage instances created by the hub service. It also ensures that all child instances can be torn down reliably on exit.

Also made it so hub tests no longer pop up console windows while running.
---
 src/zencore/process.cpp | 89 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)

(limited to 'src/zencore/process.cpp')

diff --git a/src/zencore/process.cpp b/src/zencore/process.cpp
index 4a2668912..226a94050 100644
--- a/src/zencore/process.cpp
+++ b/src/zencore/process.cpp
@@ -490,6 +490,8 @@ CreateProcNormal(const std::filesystem::path& Executable, std::string_view Comma
 	LPSECURITY_ATTRIBUTES ProcessAttributes = nullptr;
 	LPSECURITY_ATTRIBUTES ThreadAttributes	= nullptr;
 
+	const bool AssignToJob = Options.AssignToJob && Options.AssignToJob->IsValid();
+
 	DWORD CreationFlags = 0;
 	if (Options.Flags & CreateProcOptions::Flag_NewConsole)
 	{
@@ -503,6 +505,10 @@ CreateProcNormal(const std::filesystem::path& Executable, std::string_view Comma
 	{
 		CreationFlags |= CREATE_NEW_PROCESS_GROUP;
 	}
+	if (AssignToJob)
+	{
+		CreationFlags |= CREATE_SUSPENDED;
+	}
 
 	const wchar_t* WorkingDir = nullptr;
 	if (Options.WorkingDirectory != nullptr)
@@ -571,6 +577,15 @@ CreateProcNormal(const std::filesystem::path& Executable, std::string_view Comma
 		return nullptr;
 	}
 
+	if (AssignToJob)
+	{
+		if (!Options.AssignToJob->AssignProcess(ProcessInfo.hProcess))
+		{
+			ZEN_WARN("Failed to assign newly created process to job object");
+		}
+		ResumeThread(ProcessInfo.hThread);
+	}
+
 	CloseHandle(ProcessInfo.hThread);
 	return ProcessInfo.hProcess;
 }
@@ -644,6 +659,8 @@ CreateProcUnelevated(const std::filesystem::path& Executable, std::string_view C
 	};
 	PROCESS_INFORMATION ProcessInfo = {};
 
+	const bool AssignToJob = Options.AssignToJob && Options.AssignToJob->IsValid();
+
 	if (Options.Flags & CreateProcOptions::Flag_NewConsole)
 	{
 		CreateProcFlags |= CREATE_NEW_CONSOLE;
@@ -652,6 +669,10 @@ CreateProcUnelevated(const std::filesystem::path& Executable, std::string_view C
 	{
 		CreateProcFlags |= CREATE_NO_WINDOW;
 	}
+	if (AssignToJob)
+	{
+		CreateProcFlags |= CREATE_SUSPENDED;
+	}
 
 	ExtendableWideStringBuilder<256> CommandLineZ;
 	CommandLineZ << CommandLine;
@@ -679,6 +700,15 @@ CreateProcUnelevated(const std::filesystem::path& Executable, std::string_view C
 		return nullptr;
 	}
 
+	if (AssignToJob)
+	{
+		if (!Options.AssignToJob->AssignProcess(ProcessInfo.hProcess))
+		{
+			ZEN_WARN("Failed to assign newly created process to job object");
+		}
+		ResumeThread(ProcessInfo.hThread);
+	}
+
 	CloseHandle(ProcessInfo.hThread);
 	return ProcessInfo.hProcess;
 }
@@ -845,6 +875,65 @@ ProcessMonitor::IsActive() const
 
 //////////////////////////////////////////////////////////////////////////
 
+#if ZEN_PLATFORM_WINDOWS
+JobObject::JobObject() = default;
+
+JobObject::~JobObject()
+{
+	if (m_JobHandle)
+	{
+		CloseHandle(m_JobHandle);
+		m_JobHandle = nullptr;
+	}
+}
+
+void
+JobObject::Initialize()
+{
+	ZEN_ASSERT(m_JobHandle == nullptr, "JobObject already initialized");
+
+	m_JobHandle = CreateJobObjectW(nullptr, nullptr);
+	if (!m_JobHandle)
+	{
+		ZEN_WARN("Failed to create job object: {}", zen::GetLastError());
+		return;
+	}
+
+	JOBOBJECT_EXTENDED_LIMIT_INFORMATION LimitInfo = {};
+	LimitInfo.BasicLimitInformation.LimitFlags	   = JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE;
+
+	if (!SetInformationJobObject(m_JobHandle, JobObjectExtendedLimitInformation, &LimitInfo, sizeof(LimitInfo)))
+	{
+		ZEN_WARN("Failed to set job object limits: {}", zen::GetLastError());
+		CloseHandle(m_JobHandle);
+		m_JobHandle = nullptr;
+	}
+}
+
+bool
+JobObject::AssignProcess(void* ProcessHandle)
+{
+	ZEN_ASSERT(m_JobHandle != nullptr, "JobObject not initialized");
+	ZEN_ASSERT(ProcessHandle != nullptr, "ProcessHandle is null");
+
+	if (!AssignProcessToJobObject(m_JobHandle, ProcessHandle))
+	{
+		ZEN_WARN("Failed to assign process to job object: {}", zen::GetLastError());
+		return false;
+	}
+
+	return true;
+}
+
+bool
+JobObject::IsValid() const
+{
+	return m_JobHandle != nullptr;
+}
+#endif	// ZEN_PLATFORM_WINDOWS
+
+//////////////////////////////////////////////////////////////////////////
+
 bool
 IsProcessRunning(int pid, std::error_code& OutEc)
 {
-- 
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