From b80f29784c0d40f3778a3a4cc5c090b0bb92ea40 Mon Sep 17 00:00:00 2001
From: ghorsington <neigh@coder.horse>
Date: Sat, 14 May 2022 23:33:32 +0300
Subject: [PATCH] BepInEx.IL2CPP: Fix mutex checks

---
 BepInEx.Core/Utility.cs              | 17 +++++++++++++++++
 BepInEx.IL2CPP/DoorstopEntrypoint.cs |  8 +++++---
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/BepInEx.Core/Utility.cs b/BepInEx.Core/Utility.cs
index a71f731..a4252d2 100644
--- a/BepInEx.Core/Utility.cs
+++ b/BepInEx.Core/Utility.cs
@@ -320,6 +320,23 @@ public static class Utility
         return ByteArrayToString(md5.Hash);
     }
 
+    /// <summary>
+    /// Hash a list of strings using MD5
+    /// </summary>
+    /// <param name="strings">Strings to hash</param>
+    /// <returns>MD5 of the strings</returns>
+    public static string HashStrings(params string[] strings)
+    {
+        using var md5 = MD5.Create();
+
+        foreach (var str in strings)
+            md5.TransformBlock(Encoding.UTF8.GetBytes(str), 0, str.Length, null, 0);
+
+        md5.TransformFinalBlock(new byte[0], 0, 0);
+
+        return ByteArrayToString(md5.Hash);
+    }
+
     /// <summary>
     ///     Convert the given array to a hex string.
     /// </summary>
diff --git a/BepInEx.IL2CPP/DoorstopEntrypoint.cs b/BepInEx.IL2CPP/DoorstopEntrypoint.cs
index 18b2d93..5f9902e 100644
--- a/BepInEx.IL2CPP/DoorstopEntrypoint.cs
+++ b/BepInEx.IL2CPP/DoorstopEntrypoint.cs
@@ -2,6 +2,7 @@ using System;
 using System.Diagnostics;
 using System.IO;
 using System.Threading;
+using BepInEx;
 using BepInEx.IL2CPP;
 using BepInEx.Preloader.Core;
 
@@ -25,9 +26,10 @@ internal static class Entrypoint
             silentExceptionLog =
                 Path.Combine(Path.GetDirectoryName(EnvVars.DOORSTOP_PROCESS_PATH), silentExceptionLog);
 
-            mutex = new Mutex(false,
-                              Process.GetCurrentProcess().ProcessName + EnvVars.DOORSTOP_PROCESS_PATH +
-                              typeof(Doorstop.Entrypoint).FullName);
+            var mutexId = Utility.HashStrings(Process.GetCurrentProcess().ProcessName, EnvVars.DOORSTOP_PROCESS_PATH,
+                                              typeof(Entrypoint).FullName);
+
+            mutex = new Mutex(false, $"Global\\{mutexId}");
             mutex.WaitOne();
 
             UnityPreloaderRunner.PreloaderMain();