harden attach sponsor process (#14)

- Improvement: Delay exiting due to no sponsor processes by one second to handle race conditions
- Improvement: Safer IsProcessRunning check
- Improvement: make sure we can RequestApplicationExit safely from any thread

1 files changed, 17 insertions, 7 deletions

diff --git a/src/zencore/process.cpp b/src/zencore/process.cpp
index e0a395494..d8be0d343 100644
--- a/src/zencore/process.cpp
+++ b/src/zencore/process.cpp
@@ -661,14 +661,13 @@ IsProcessRunning(int pid)
 	if (!hProc)
 	{
 		DWORD Error = zen::GetLastError();
-
 		if (Error == ERROR_INVALID_PARAMETER)
 		{
 			return false;
 		}
-
 		ThrowSystemError(Error, fmt::format("failed to open process with pid {}", pid));
 	}
+	auto _ = MakeGuard([hProc]() { CloseHandle(hProc); });
 
 	bool  bStillActive = true;
 	DWORD ExitCode	   = 0;
@@ -678,14 +677,25 @@ IsProcessRunning(int pid)
 	}
 	else
 	{
-		ZEN_WARN("Unable to get exit code from handle for process '{}', treating the process as active", pid);
+		DWORD Error = GetLastError();
+		ThrowSystemError(Error, fmt::format("failed to get process exit code for pid {}", pid));
 	}
-
-	CloseHandle(hProc);
-
 	return bStillActive;
 #elif ZEN_PLATFORM_LINUX || ZEN_PLATFORM_MAC
-	return (kill(pid_t(pid), 0) == 0);
+	int Res		  = kill(pid_t(pid), 0);
+	if (Res == 0)
+	{
+		return true;
+	}
+	int Error = errno;
+	if (Error == ESRCH)	 // No such process
+	{
+		return false;
+	}
+	else
+	{
+		ThrowSystemError(Error, fmt::format("Failed to signal running process %d: %d", pid, Error));
+	}
 #endif
 }