fix race contdition when signaling shutdown of process and waiting for completion (#539)

1 files changed, 48 insertions, 8 deletions

diff --git a/src/zencore/thread.cpp b/src/zencore/thread.cpp
index 1f1b1b8f5..99d7cdc61 100644
--- a/src/zencore/thread.cpp
+++ b/src/zencore/thread.cpp
@@ -606,7 +606,7 @@ ProcessHandle::Terminate(int ExitCode)
 	bSuccess		 = (WaitResult != WAIT_OBJECT_0);
 #elif ZEN_PLATFORM_LINUX || ZEN_PLATFORM_MAC
 	ZEN_UNUSED(ExitCode);
-	bSuccess			= (kill(m_Pid, SIGKILL) == 0);
+	bSuccess = (kill(m_Pid, SIGKILL) == 0);
 #endif
 
 	if (!bSuccess)
@@ -650,25 +650,65 @@ ProcessHandle::Wait(int TimeoutMs)
 			break;
 	}
 #elif ZEN_PLATFORM_LINUX || ZEN_PLATFORM_MAC
+	if (TimeoutMs < 0)
+	{
+		int WaitState = 0;
+		int Res		  = waitpid(m_Pid, &WaitState, WCONTINUED | WUNTRACED);
+		if (Res == -1)
+		{
+			int32_t LastError = zen::GetLastError();
+			if (LastError == ECHILD || LastError == ESRCH)
+			{
+				return true;
+			}
+			ThrowSystemError(static_cast<uint32_t>(LastError), "Process::Wait waitpid failed"sv);
+		}
+		if (WIFEXITED(WaitState))
+		{
+			return true;
+		}
+		if (WIFSIGNALED(WaitState))
+		{
+			return true;
+		}
+		return false;
+	}
+
 	const int SleepMs	= 20;
 	timespec  SleepTime = {0, SleepMs * 1000 * 1000};
-	for (int i = 0;; i += SleepMs)
+	for (int SleepedTimeMS = 0;; SleepedTimeMS += SleepMs)
 	{
-#	if ZEN_PLATFORM_MAC
 		int WaitState = 0;
-		waitpid(m_Pid, &WaitState, WNOHANG | WCONTINUED | WUNTRACED);
-#	endif
+		int Res		  = waitpid(m_Pid, &WaitState, WNOHANG | WCONTINUED | WUNTRACED);
+		if (Res == -1)
+		{
+			int32_t LastError = zen::GetLastError();
+			if (LastError == ECHILD || LastError == ESRCH)
+			{
+				return true;
+			}
+			ThrowSystemError(static_cast<uint32_t>(LastError), "Process::Wait waitpid failed"sv);
+		}
+		if (WIFEXITED(WaitState))
+		{
+			return true;
+		}
+		if (WIFSIGNALED(WaitState))
+		{
+			return true;
+		}
 
 		if (kill(m_Pid, 0) < 0)
 		{
-			if (zen::GetLastError() == ESRCH)
+			int32_t LastError = zen::GetLastError();
+			if (LastError == ECHILD || LastError == ESRCH)
 			{
 				return true;
 			}
-			break;
+			ThrowSystemError(static_cast<uint32_t>(LastError), "Process::Wait kill failed"sv);
 		}
 
-		if (TimeoutMs >= 0 && i >= TimeoutMs)
+		if (SleepedTimeMS >= TimeoutMs)
 		{
 			return false;
 		}