From b0c002ddb0ea929837544a82564195d52df014ea Mon Sep 17 00:00:00 2001
From: Jordan <Cyberboss@users.noreply.github.com>
Date: Mon, 19 Jun 2023 01:00:43 -0400
Subject: [PATCH] Host.Watchdog forwards SIGUSR1 to child

---
 build/Version.props                           |  2 +-
 .../Tgstation.Server.Host.Watchdog.csproj     |  2 +
 .../Watchdog.cs                               | 37 ++++++++++++++++++-
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/build/Version.props b/build/Version.props
index 308fb7a8c3..f3102f5c76 100644
--- a/build/Version.props
+++ b/build/Version.props
@@ -11,7 +11,7 @@
     <TgsClientVersion>12.0.0</TgsClientVersion>
     <TgsDmapiVersion>6.5.0</TgsDmapiVersion>
     <TgsInteropVersion>5.6.1</TgsInteropVersion>
-    <TgsHostWatchdogVersion>1.2.2</TgsHostWatchdogVersion>
+    <TgsHostWatchdogVersion>1.3.0</TgsHostWatchdogVersion>
     <TgsContainerScriptVersion>1.2.1</TgsContainerScriptVersion>
     <TgsMigratorVersion>1.0.1</TgsMigratorVersion>
   </PropertyGroup>
diff --git a/src/Tgstation.Server.Host.Watchdog/Tgstation.Server.Host.Watchdog.csproj b/src/Tgstation.Server.Host.Watchdog/Tgstation.Server.Host.Watchdog.csproj
index 97c746f05c..0277b02fdd 100644
--- a/src/Tgstation.Server.Host.Watchdog/Tgstation.Server.Host.Watchdog.csproj
+++ b/src/Tgstation.Server.Host.Watchdog/Tgstation.Server.Host.Watchdog.csproj
@@ -24,6 +24,8 @@
   <ItemGroup>
     <!-- Usage: Logging abstractions -->
     <PackageReference Include="Microsoft.Extensions.Logging" Version="7.0.0" />
+    <!-- Usage: POSIX support for signals -->
+    <PackageReference Include="Mono.Posix.NETStandard" Version="1.0.0" />
     <!-- Usage: Linting -->
     <PackageReference Include="StyleCop.Analyzers" Version="1.1.118">
       <PrivateAssets>all</PrivateAssets>
diff --git a/src/Tgstation.Server.Host.Watchdog/Watchdog.cs b/src/Tgstation.Server.Host.Watchdog/Watchdog.cs
index 0092ea6140..c45a25b364 100644
--- a/src/Tgstation.Server.Host.Watchdog/Watchdog.cs
+++ b/src/Tgstation.Server.Host.Watchdog/Watchdog.cs
@@ -11,6 +11,9 @@ using System.Threading.Tasks;
 
 using Microsoft.Extensions.Logging;
 
+using Mono.Unix;
+using Mono.Unix.Native;
+
 using Tgstation.Server.Host.Common;
 
 namespace Tgstation.Server.Host.Watchdog
@@ -148,6 +151,7 @@ namespace Tgstation.Server.Host.Watchdog
 							try
 							{
 								process.Start();
+								var childPid = process.Id;
 
 								using (var processCts = new CancellationTokenSource())
 								using (processCts.Token.Register(() => tcs.TrySetResult(null)))
@@ -173,7 +177,38 @@ namespace Tgstation.Server.Host.Watchdog
 										logger.LogWarning(ex, "Error triggering timeout!");
 									}
 								}))
-									await tcs.Task.ConfigureAwait(false);
+								{
+									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)
+										{
+											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!");
+										}
+									}
+								}
 							}
 							catch (InvalidOperationException ex)
 							{