improved process monitoring behaviour with invalid pids (#16)

4 files changed, 42 insertions, 14 deletions

diff --git a/src/zencore/include/zencore/process.h b/src/zencore/include/zencore/process.h
index d90a32301..a14aa5a71 100644
--- a/src/zencore/include/zencore/process.h
+++ b/src/zencore/include/zencore/process.h
@@ -22,6 +22,7 @@ public:
 	ZENCORE_API ~ProcessHandle();
 
 	ZENCORE_API void			   Initialize(int Pid);
+	ZENCORE_API void			   Initialize(int Pid, std::error_code& OutEc);
 	ZENCORE_API void			   Initialize(void* ProcessHandle);	 /// Initialize with an existing handle - takes ownership of the handle
 	ZENCORE_API [[nodiscard]] bool IsRunning() const;
 	ZENCORE_API [[nodiscard]] bool IsValid() const;
diff --git a/src/zencore/process.cpp b/src/zencore/process.cpp
index 2d0ec2de6..e0a395494 100644
--- a/src/zencore/process.cpp
+++ b/src/zencore/process.cpp
@@ -75,8 +75,9 @@ ProcessHandle::~ProcessHandle()
 }
 
 void
-ProcessHandle::Initialize(int Pid)
+ProcessHandle::Initialize(int Pid, std::error_code& OutEc)
 {
+	OutEc.clear();
 	ZEN_ASSERT(m_ProcessHandle == nullptr);
 
 #if ZEN_PLATFORM_WINDOWS
@@ -90,7 +91,21 @@ ProcessHandle::Initialize(int Pid)
 
 	if (!m_ProcessHandle)
 	{
-		ThrowLastError(fmt::format("ProcessHandle::Initialize(pid: {}) failed", Pid));
+		OutEc = MakeErrorCodeFromLastError();
+	}
+
+	m_Pid = Pid;
+}
+
+void
+ProcessHandle::Initialize(int Pid)
+{
+	std::error_code Ec;
+	Initialize(Pid, Ec);
+
+	if (Ec)
+	{
+		throw std::system_error(Ec, fmt::format("ProcessHandle::Initialize(pid: {}) failed", Pid));
 	}
 
 	m_Pid = Pid;
@@ -576,12 +591,19 @@ ProcessMonitor::IsRunning()
 
 #if ZEN_PLATFORM_WINDOWS
 		DWORD ExitCode = 0;
-		GetExitCodeProcess(Proc, &ExitCode);
 
-		ProcIsActive = (ExitCode == STILL_ACTIVE);
-		if (!ProcIsActive)
+		if (Proc)
+		{
+			GetExitCodeProcess(Proc, &ExitCode);
+			ProcIsActive = (ExitCode == STILL_ACTIVE);
+			if (!ProcIsActive)
+			{
+				CloseHandle(Proc);
+			}
+		}
+		else
 		{
-			CloseHandle(Proc);
+			ProcIsActive = false;
 		}
 #else
 		int Pid		 = int(intptr_t(Proc));
@@ -613,11 +635,8 @@ ProcessMonitor::AddPid(int Pid)
 	ProcessHandle = HandleType(intptr_t(Pid));
 #endif
 
-	if (ProcessHandle)
-	{
-		RwLock::ExclusiveLockScope _(m_Lock);
-		m_ProcessHandles.push_back(ProcessHandle);
-	}
+	RwLock::ExclusiveLockScope _(m_Lock);
+	m_ProcessHandles.push_back(ProcessHandle);
 }
 
 bool
diff --git a/src/zenserver/zenserver.cpp b/src/zenserver/zenserver.cpp
index d8176678d..daec743a0 100644
--- a/src/zenserver/zenserver.cpp
+++ b/src/zenserver/zenserver.cpp
@@ -124,8 +124,9 @@ ZenServer::Initialize(const ZenServerOptions& ServerOptions, ZenServerState::Zen
 
 	if (ParentPid)
 	{
-		ProcessHandle OwnerProcess;
-		OwnerProcess.Initialize(ParentPid);
+		std::error_code Ec;
+		ProcessHandle	OwnerProcess;
+		OwnerProcess.Initialize(ParentPid, /* out */ Ec);
 
 		if (!OwnerProcess.IsValid())
 		{
diff --git a/src/zenutil/zenserverprocess.cpp b/src/zenutil/zenserverprocess.cpp
index 0b0127f93..3667ad2c6 100644
--- a/src/zenutil/zenserverprocess.cpp
+++ b/src/zenutil/zenserverprocess.cpp
@@ -673,7 +673,14 @@ ZenServerInstance::AttachToRunningServer(int BasePort)
 		throw std::runtime_error("No server found");
 	}
 
-	m_Process.Initialize(Entry->Pid);
+	std::error_code Ec;
+	m_Process.Initialize(Entry->Pid, Ec);
+
+	if (Ec)
+	{
+		throw std::system_error(Ec, fmt::format("failed to attach to running server on port {} using pid {}", BasePort, Entry->Pid.load()));
+	}
+
 	CreateShutdownEvent(Entry->EffectiveListenPort);
 	m_BasePort = Entry->EffectiveListenPort;
 }