From 5119ecfa0328964d46897b7b9d6dcc5d6ca8423a Mon Sep 17 00:00:00 2001
From: Jordan Dominion <Cyberboss@users.noreply.github.com>
Date: Tue, 20 Jun 2023 08:22:07 -0400
Subject: [PATCH] Use signal checking that works in Host.Watchdog

---
 .../Watchdog.cs                               | 67 ++++++++++++-------
 1 file changed, 44 insertions(+), 23 deletions(-)

diff --git a/src/Tgstation.Server.Host.Watchdog/Watchdog.cs b/src/Tgstation.Server.Host.Watchdog/Watchdog.cs
index c45a25b364..3b9ee3bc63 100644
--- a/src/Tgstation.Server.Host.Watchdog/Watchdog.cs
+++ b/src/Tgstation.Server.Host.Watchdog/Watchdog.cs
@@ -181,31 +181,52 @@ namespace Tgstation.Server.Host.Watchdog
 									var processTask = tcs.Task;
 									while (!processTask.IsCompleted)
 									{
-										using var unixSignal = isWindows
-											? null
-											: new UnixSignal(Signum.SIGUSR1);
-
 										var signalTcs = new TaskCompletionSource<object>();
-
-										if (!isWindows)
-											ThreadPool.RegisterWaitForSingleObject(
-												unixSignal,
-												(o, timeout) => signalTcs.SetResult(null),
-												null,
-												Timeout.Infinite,
-												true);
-
-										var signalTask = signalTcs.Task;
-
-										var completedTask = await Task.WhenAny(processTask, signalTask);
-										if (completedTask == signalTask)
+										using var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+										async ValueTask CheckSignal()
 										{
-											logger.LogInformation("Received SIGUSR1, forwarding to main TGS process!");
-											var result = Syscall.kill(childPid, Signum.SIGUSR1);
-											if (result != 0)
-												logger.LogWarning(
-													new UnixIOException(Stdlib.GetLastError()),
-													"Failed to forward SIGUSR1!");
+											if (isWindows)
+												return;
+
+											try
+											{
+												using var unixSignal = new UnixSignal(Signum.SIGUSR1);
+												if (!unixSignal.IsSet)
+												{
+													logger.LogTrace("Waiting for SIGUSR1...");
+													while (!unixSignal.IsSet)
+														await Task.Delay(TimeSpan.FromMilliseconds(250), cts.Token);
+
+													logger.LogTrace("SIGUSR1 received!");
+												}
+												else
+													logger.LogDebug("SIGUSR1 has already been sent");
+											}
+											catch (OperationCanceledException)
+											{
+											}
+										}
+
+										var checkerTask = CheckSignal();
+										try
+										{
+											var signalTask = signalTcs.Task;
+
+											var completedTask = await Task.WhenAny(processTask, signalTask);
+											if (completedTask == signalTask)
+											{
+												logger.LogInformation("Received SIGUSR1, forwarding to main TGS process!");
+												var result = Syscall.kill(childPid, Signum.SIGUSR1);
+												if (result != 0)
+													logger.LogWarning(
+														new UnixIOException(Stdlib.GetLastError()),
+														"Failed to forward SIGUSR1!");
+											}
+										}
+										finally
+										{
+											cts.Cancel();
+											await checkerTask;
 										}
 									}
 								}