--- a/src/java.base/share/classes/java/lang/Shutdown.java Fri Feb 23 14:26:29 2018 -0500
+++ b/src/java.base/share/classes/java/lang/Shutdown.java Fri Feb 23 12:10:56 2018 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 1999, 2005, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -26,35 +26,33 @@
package java.lang;
+import jdk.internal.misc.VM;
+
/**
* Package-private utility class containing data structures and logic
* governing the virtual-machine shutdown sequence.
*
* @author Mark Reinhold
* @since 1.3
+ *
+ * @see java.io.Console
+ * @see ApplicationShutdownHooks
+ * @see java.io.DeleteOnExitHook
*/
class Shutdown {
- /* Shutdown state */
- private static final int RUNNING = 0;
- private static final int HOOKS = 1;
- private static final int FINALIZERS = 2;
- private static int state = RUNNING;
-
- /* Should we run all finalizers upon exit? */
- private static boolean runFinalizersOnExit = false;
-
// The system shutdown hooks are registered with a predefined slot.
// The list of shutdown hooks is as follows:
// (0) Console restore hook
- // (1) Application hooks
+ // (1) ApplicationShutdownHooks that invokes all registered application
+ // shutdown hooks and waits until they finish
// (2) DeleteOnExit hook
private static final int MAX_SYSTEM_HOOKS = 10;
private static final Runnable[] hooks = new Runnable[MAX_SYSTEM_HOOKS];
// the index of the currently running shutdown hook to the hooks array
- private static int currentRunningHook = 0;
+ private static int currentRunningHook = -1;
/* The preceding static fields are protected by this lock */
private static class Lock { };
@@ -63,17 +61,9 @@
/* Lock object for the native halt method */
private static Object haltLock = new Lock();
- /* Invoked by Runtime.runFinalizersOnExit */
- static void setRunFinalizersOnExit(boolean run) {
- synchronized (lock) {
- runFinalizersOnExit = run;
- }
- }
-
-
/**
- * Add a new shutdown hook. Checks the shutdown state and the hook itself,
- * but does not do any security checks.
+ * Add a new system shutdown hook. Checks the shutdown state and
+ * the hook itself, but does not do any security checks.
*
* The registerShutdownInProgress parameter should be false except
* registering the DeleteOnExitHook since the first file may
@@ -92,15 +82,18 @@
* already passes the given slot
*/
static void add(int slot, boolean registerShutdownInProgress, Runnable hook) {
+ if (slot < 0 || slot >= MAX_SYSTEM_HOOKS) {
+ throw new IllegalArgumentException("Invalid slot: " + slot);
+ }
synchronized (lock) {
if (hooks[slot] != null)
throw new InternalError("Shutdown hook at slot " + slot + " already registered");
if (!registerShutdownInProgress) {
- if (state > RUNNING)
+ if (currentRunningHook >= 0)
throw new IllegalStateException("Shutdown in progress");
} else {
- if (state > HOOKS || (state == HOOKS && slot <= currentRunningHook))
+ if (VM.isShutdown() || slot <= currentRunningHook)
throw new IllegalStateException("Shutdown in progress");
}
@@ -108,9 +101,23 @@
}
}
- /* Run all registered shutdown hooks
+ /* Run all system shutdown hooks.
+ *
+ * The system shutdown hooks are run in the thread synchronized on
+ * Shutdown.class. Other threads calling Runtime::exit, Runtime::halt
+ * or JNI DestroyJavaVM will block indefinitely.
+ *
+ * ApplicationShutdownHooks is registered as one single hook that starts
+ * all application shutdown hooks and waits until they finish.
*/
private static void runHooks() {
+ synchronized (lock) {
+ /* Guard against the possibility of a daemon thread invoking exit
+ * after DestroyJavaVM initiates the shutdown sequence
+ */
+ if (VM.isShutdown()) return;
+ }
+
for (int i=0; i < MAX_SYSTEM_HOOKS; i++) {
try {
Runnable hook;
@@ -121,13 +128,16 @@
hook = hooks[i];
}
if (hook != null) hook.run();
- } catch(Throwable t) {
+ } catch (Throwable t) {
if (t instanceof ThreadDeath) {
ThreadDeath td = (ThreadDeath)t;
throw td;
}
}
}
+
+ // set shutdown state
+ VM.shutdown();
}
/* The halt method is synchronized on the halt lock
@@ -142,74 +152,22 @@
static native void halt0(int status);
- /* Wormhole for invoking java.lang.ref.Finalizer.runAllFinalizers */
- private static native void runAllFinalizers();
-
-
- /* The actual shutdown sequence is defined here.
- *
- * If it weren't for runFinalizersOnExit, this would be simple -- we'd just
- * run the hooks and then halt. Instead we need to keep track of whether
- * we're running hooks or finalizers. In the latter case a finalizer could
- * invoke exit(1) to cause immediate termination, while in the former case
- * any further invocations of exit(n), for any n, simply stall. Note that
- * if on-exit finalizers are enabled they're run iff the shutdown is
- * initiated by an exit(0); they're never run on exit(n) for n != 0 or in
- * response to SIGINT, SIGTERM, etc.
- */
- private static void sequence() {
- synchronized (lock) {
- /* Guard against the possibility of a daemon thread invoking exit
- * after DestroyJavaVM initiates the shutdown sequence
- */
- if (state != HOOKS) return;
- }
- runHooks();
- boolean rfoe;
- synchronized (lock) {
- state = FINALIZERS;
- rfoe = runFinalizersOnExit;
- }
- if (rfoe) runAllFinalizers();
- }
-
-
/* Invoked by Runtime.exit, which does all the security checks.
* Also invoked by handlers for system-provided termination events,
* which should pass a nonzero status code.
*/
static void exit(int status) {
- boolean runMoreFinalizers = false;
synchronized (lock) {
- if (status != 0) runFinalizersOnExit = false;
- switch (state) {
- case RUNNING: /* Initiate shutdown */
- state = HOOKS;
- break;
- case HOOKS: /* Stall and halt */
- break;
- case FINALIZERS:
- if (status != 0) {
- /* Halt immediately on nonzero status */
- halt(status);
- } else {
- /* Compatibility with old behavior:
- * Run more finalizers and then halt
- */
- runMoreFinalizers = runFinalizersOnExit;
- }
- break;
+ if (status != 0 && VM.isShutdown()) {
+ /* Halt immediately on nonzero status */
+ halt(status);
}
}
- if (runMoreFinalizers) {
- runAllFinalizers();
- halt(status);
- }
synchronized (Shutdown.class) {
/* Synchronize on the class object, causing any other thread
* that attempts to initiate shutdown to stall indefinitely
*/
- sequence();
+ runHooks();
halt(status);
}
}
@@ -220,18 +178,8 @@
* actually halt the VM.
*/
static void shutdown() {
- synchronized (lock) {
- switch (state) {
- case RUNNING: /* Initiate shutdown */
- state = HOOKS;
- break;
- case HOOKS: /* Stall and then return */
- case FINALIZERS:
- break;
- }
- }
synchronized (Shutdown.class) {
- sequence();
+ runHooks();
}
}