From 847063d6fa9d1f4d595077806525d8da67670155 Mon Sep 17 00:00:00 2001
From: Voltstro <me@voltstro.dev>
Date: Sat, 16 Mar 2024 22:07:19 +1000
Subject: [PATCH] Linux set process to kill it self when parent process dies

---
 .../Core/EngineEntryPoint.cs                  | 11 +++++++++
 .../Native/Linux/SysPrctl.cs                  | 23 +++++++++++++++++++
 ...udios.UnityWebBrowser.Engine.Shared.csproj |  3 +++
 3 files changed, 37 insertions(+)
 create mode 100644 src/VoltstroStudios.UnityWebBrowser.Engine.Shared/Native/Linux/SysPrctl.cs

diff --git a/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/Core/EngineEntryPoint.cs b/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/Core/EngineEntryPoint.cs
index e5a189f9..ece4537d 100644
--- a/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/Core/EngineEntryPoint.cs
+++ b/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/Core/EngineEntryPoint.cs
@@ -17,6 +17,10 @@
 using VoltstroStudios.UnityWebBrowser.Engine.Shared.Popups;
 using VoltstroStudios.UnityWebBrowser.Engine.Shared.ReadWriters;
 
+#if LINUX
+using VoltstroStudios.UnityWebBrowser.Engine.Shared.Native.Linux;
+#endif
+
 namespace VoltstroStudios.UnityWebBrowser.Engine.Shared.Core;
 
 /// <summary>
@@ -69,6 +73,13 @@ internal abstract class EngineEntryPoint : IDisposable
     /// <returns></returns>
     public int Main(string[] args)
     {
+        #if LINUX
+        //On Linux, tell this child process to kill it self when it's parent process dies
+        //Option: 1 -> PR_SET_PDEATHSIG (include/uapi/linux/prctl.h)
+        //Arg2: 9 -> SIGKILL (arch/x86/include/uapi/asm/signal.h)
+        SysPrctl.prctl(1, 9);
+        #endif
+        
         //We got a lot of arguments
 
         //Url to start with
diff --git a/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/Native/Linux/SysPrctl.cs b/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/Native/Linux/SysPrctl.cs
new file mode 100644
index 00000000..c086a750
--- /dev/null
+++ b/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/Native/Linux/SysPrctl.cs
@@ -0,0 +1,23 @@
+// UnityWebBrowser (UWB)
+// Copyright (c) 2021-2024 Voltstro-Studios
+// 
+// This project is under the MIT license. See the LICENSE.md file for more details.
+
+using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
+
+namespace VoltstroStudios.UnityWebBrowser.Engine.Shared.Native.Linux;
+
+[SupportedOSPlatform("Linux")]
+internal static class SysPrctl
+{
+    /// <summary>
+    ///     Operations on a process or thread
+    ///     https://www.man7.org/linux/man-pages/man2/prctl.2.html
+    /// </summary>
+    /// <param name="option"></param>
+    /// <param name="arg2"></param>
+    /// <returns></returns>
+    [DllImport("libc")]
+    public static extern int prctl(int option, ulong arg2);
+}
\ No newline at end of file
diff --git a/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/VoltstroStudios.UnityWebBrowser.Engine.Shared.csproj b/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/VoltstroStudios.UnityWebBrowser.Engine.Shared.csproj
index 1c570a7e..445dffd1 100644
--- a/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/VoltstroStudios.UnityWebBrowser.Engine.Shared.csproj
+++ b/src/VoltstroStudios.UnityWebBrowser.Engine.Shared/VoltstroStudios.UnityWebBrowser.Engine.Shared.csproj
@@ -1,5 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
+    <Import Project="../Imports/NativeDefines.props" />
     <Import Project="../Imports/Properties.props" />
 
     <PropertyGroup>
@@ -31,4 +32,6 @@
       <ProjectReference Include="..\VoltstroStudios.UnityWebBrowser.Shared\VoltstroStudios.UnityWebBrowser.Shared.csproj" />
     </ItemGroup>
 
+    <Import Project="../Imports/NatvieDefines.targets" />
+
 </Project>