From e231dc58a43fc554fa22970df42b43f2e59f07ba Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 12 Apr 2020 15:50:48 -0400
Subject: [PATCH] Allow shutting down server during a watchdog hang gracefully

If the request to shut down the server is received while we are in
a watchdog hang, immediately treat it as a crash and begin the shutdown
process. Shutdown process is now improved to also shutdown cleanly when
not using restart scripts either.

If a server is deadlocked, a server owner can send SIGUP (or any other signal
the JVM understands to shut down as it currently does) and the watchdog
will no longer need to wait until the full timeout, allowing you to trigger
a close process and try to shut the server down gracefully, saving player and
world data.

Previously there was no way to trigger this outside of waiting for a full watchdog
timeout, which may be set to a really long time...

diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 2686874f2..a9b533751 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -176,7 +176,7 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
     public boolean serverAutoSave = false; // Paper
     public File bukkitDataPackFolder;
     public CommandDispatcher vanillaCommandDispatcher;
-    private boolean forceTicks;
+    public boolean forceTicks; // Paper
     // CraftBukkit end
     // Spigot start
     public static final int TPS = 20;
@@ -795,6 +795,7 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
         }
         // Spigot end
         com.destroystokyo.paper.io.PaperFileIOThread.Holder.INSTANCE.close(true, true); // Paper
+        System.exit(0); // Paper
     }
 
     public String getServerIp() {
diff --git a/src/main/java/org/spigotmc/RestartCommand.java b/src/main/java/org/spigotmc/RestartCommand.java
index aefea3a9a..123de5ac9 100644
--- a/src/main/java/org/spigotmc/RestartCommand.java
+++ b/src/main/java/org/spigotmc/RestartCommand.java
@@ -139,7 +139,7 @@ public class RestartCommand extends Command
     // Paper end
 
     // Paper start - copied from above and modified to return if the hook registered
-    private static boolean addShutdownHook(String restartScript)
+    public static boolean addShutdownHook(String restartScript)
     {
         String[] split = restartScript.split( " " );
         if ( split.length > 0 && new File( split[0] ).isFile() )
diff --git a/src/main/java/org/spigotmc/WatchdogThread.java b/src/main/java/org/spigotmc/WatchdogThread.java
index 5bdcdcf9e..704e8426a 100644
--- a/src/main/java/org/spigotmc/WatchdogThread.java
+++ b/src/main/java/org/spigotmc/WatchdogThread.java
@@ -69,7 +69,7 @@ public class WatchdogThread extends Thread
             long currentTime = monotonicMillis();
             if ( lastTick != 0 && currentTime > lastTick + earlyWarningEvery && !Boolean.getBoolean("disable.watchdog") )
             {
-                boolean isLongTimeout = currentTime > lastTick + timeoutTime;
+                boolean isLongTimeout = currentTime > lastTick + timeoutTime || !MinecraftServer.getServer().isRunning();
                 // Don't spam early warning dumps
                 if ( !isLongTimeout && (earlyWarningEvery <= 0 || !hasStarted || currentTime < lastEarlyWarning + earlyWarningEvery || currentTime < lastTick + earlyWarningDelay)) continue;
                 if ( !isLongTimeout && MinecraftServer.getServer().hasStopped()) continue; // Don't spam early watchdog warnings during shutdown, we'll come back to this...
@@ -135,9 +135,15 @@ public class WatchdogThread extends Thread
 
                 if ( isLongTimeout )
                 {
-                if ( restart && !MinecraftServer.getServer().hasStopped() )
+                if ( !MinecraftServer.getServer().hasStopped() )
                 {
-                    RestartCommand.restart();
+                    AsyncCatcher.enabled = false; // Disable async catcher incase it interferes with us
+                    AsyncCatcher.shuttingDown = true;
+                    MinecraftServer.getServer().forceTicks = true;
+                    if (restart) {
+                        RestartCommand.addShutdownHook( SpigotConfig.restartScript );
+                    }
+                    MinecraftServer.getServer().close();
                 }
                 break;
                 } // Paper end
-- 
2.25.1