Reintroduce entitlement check on System.exit (#119757)

Author: ldematte

libs/entitlement/bridge/src/main/java/org/elasticsearch/entitlement/bridge/EntitlementChecker.java

@@ -37,6 +37,8 @@ public interface EntitlementChecker {
 
     void check$java_lang_Runtime$halt(Class<?> callerClass, Runtime runtime, int status);
 
+    void check$java_lang_System$$exit(Class<?> callerClass, int status);
+
     ////////////////////
     //
     // ClassLoader ctor

libs/entitlement/qa/common/src/main/java/org/elasticsearch/entitlement/qa/common/RestEntitlementsCheckAction.java

@@ -83,6 +83,7 @@ static CheckAction alwaysDenied(Runnable action) {
     private static final Map<String, CheckAction> checkActions = Map.ofEntries(
         entry("runtime_exit", deniedToPlugins(RestEntitlementsCheckAction::runtimeExit)),
         entry("runtime_halt", deniedToPlugins(RestEntitlementsCheckAction::runtimeHalt)),
+        entry("system_exit", deniedToPlugins(RestEntitlementsCheckAction::systemExit)),
         entry("create_classloader", forPlugins(RestEntitlementsCheckAction::createClassLoader)),
         entry("processBuilder_start", deniedToPlugins(RestEntitlementsCheckAction::processBuilder_start)),
         entry("processBuilder_startPipeline", deniedToPlugins(RestEntitlementsCheckAction::processBuilder_startPipeline)),
@@ -153,6 +154,11 @@ private static void runtimeHalt() {
         Runtime.getRuntime().halt(123);
     }
 
+    @SuppressForbidden(reason = "Specifically testing System.exit")
+    private static void systemExit() {
+        System.exit(123);
+    }
+
     private static void createClassLoader() {
         try (var classLoader = new URLClassLoader("test", new URL[0], RestEntitlementsCheckAction.class.getClassLoader())) {
             logger.info("Created URLClassLoader [{}]", classLoader.getName());

libs/entitlement/src/main/java/org/elasticsearch/entitlement/runtime/api/ElasticsearchEntitlementChecker.java

@@ -51,6 +51,11 @@ public ElasticsearchEntitlementChecker(PolicyManager policyManager) {
         policyManager.checkExitVM(callerClass);
     }
 
+    @Override
+    public void check$java_lang_System$$exit(Class<?> callerClass, int status) {
+        policyManager.checkExitVM(callerClass);
+    }
+
     @Override
     public void check$java_lang_ClassLoader$(Class<?> callerClass) {
         policyManager.checkCreateClassLoader(callerClass);