| /* |
| * Copyright (c) 1996, 2016, 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 |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package jdk.internal.misc; |
| |
| import static java.lang.Thread.State.*; |
| import java.util.Map; |
| import java.util.HashMap; |
| import java.util.Properties; |
| import java.util.Collections; |
| |
| public class VM { |
| |
| // the init level when the VM is fully initialized |
| private static final int JAVA_LANG_SYSTEM_INITED = 1; |
| private static final int MODULE_SYSTEM_INITED = 2; |
| private static final int SYSTEM_LOADER_INITIALIZING = 3; |
| private static final int SYSTEM_BOOTED = 4; |
| |
| // 0, 1, 2, ... |
| private static volatile int initLevel; |
| private static final Object lock = new Object(); |
| |
| /** |
| * Sets the init level. |
| * |
| * @see java.lang.System#initPhase1 |
| * @see java.lang.System#initPhase2 |
| * @see java.lang.System#initPhase3 |
| */ |
| public static void initLevel(int value) { |
| synchronized (lock) { |
| if (value <= initLevel || value > SYSTEM_BOOTED) |
| throw new InternalError("Bad level: " + value); |
| initLevel = value; |
| lock.notifyAll(); |
| } |
| } |
| |
| /** |
| * Returns the current init level. |
| */ |
| public static int initLevel() { |
| return initLevel; |
| } |
| |
| /** |
| * Waits for the init level to get the given value. |
| * |
| * @see java.lang.ref.Finalizer |
| */ |
| public static void awaitInitLevel(int value) throws InterruptedException { |
| synchronized (lock) { |
| while (initLevel < value) { |
| lock.wait(); |
| } |
| } |
| } |
| |
| /** |
| * Returns {@code true} if the module system has been initialized. |
| * @see java.lang.System#initPhase2 |
| */ |
| public static boolean isModuleSystemInited() { |
| return VM.initLevel() >= MODULE_SYSTEM_INITED; |
| } |
| |
| /** |
| * Returns {@code true} if the VM is fully initialized. |
| */ |
| public static boolean isBooted() { |
| return initLevel >= SYSTEM_BOOTED; |
| } |
| |
| // A user-settable upper limit on the maximum amount of allocatable direct |
| // buffer memory. This value may be changed during VM initialization if |
| // "java" is launched with "-XX:MaxDirectMemorySize=<size>". |
| // |
| // The initial value of this field is arbitrary; during JRE initialization |
| // it will be reset to the value specified on the command line, if any, |
| // otherwise to Runtime.getRuntime().maxMemory(). |
| // |
| private static long directMemory = 64 * 1024 * 1024; |
| |
| // Returns the maximum amount of allocatable direct buffer memory. |
| // The directMemory variable is initialized during system initialization |
| // in the saveAndRemoveProperties method. |
| // |
| public static long maxDirectMemory() { |
| return directMemory; |
| } |
| |
| // User-controllable flag that determines if direct buffers should be page |
| // aligned. The "-XX:+PageAlignDirectMemory" option can be used to force |
| // buffers, allocated by ByteBuffer.allocateDirect, to be page aligned. |
| private static boolean pageAlignDirectMemory; |
| |
| // Returns {@code true} if the direct buffers should be page aligned. This |
| // variable is initialized by saveAndRemoveProperties. |
| public static boolean isDirectMemoryPageAligned() { |
| return pageAlignDirectMemory; |
| } |
| |
| /** |
| * Returns true if the given class loader is the bootstrap class loader |
| * or the platform class loader. |
| */ |
| public static boolean isSystemDomainLoader(ClassLoader loader) { |
| return loader == null || loader == ClassLoader.getPlatformClassLoader(); |
| } |
| |
| /** |
| * Returns the system property of the specified key saved at |
| * system initialization time. This method should only be used |
| * for the system properties that are not changed during runtime. |
| * |
| * Note that the saved system properties do not include |
| * the ones set by java.lang.VersionProps.init(). |
| */ |
| public static String getSavedProperty(String key) { |
| if (savedProps == null) |
| throw new IllegalStateException("Not yet initialized"); |
| |
| return savedProps.get(key); |
| } |
| |
| /** |
| * Gets an unmodifiable view of the system properties saved at system |
| * initialization time. This method should only be used |
| * for the system properties that are not changed during runtime. |
| * |
| * Note that the saved system properties do not include |
| * the ones set by java.lang.VersionProps.init(). |
| */ |
| public static Map<String, String> getSavedProperties() { |
| if (savedProps == null) |
| throw new IllegalStateException("Not yet initialized"); |
| |
| return savedProps; |
| } |
| |
| private static Map<String, String> savedProps; |
| |
| // Save a private copy of the system properties and remove |
| // the system properties that are not intended for public access. |
| // |
| // This method can only be invoked during system initialization. |
| public static void saveAndRemoveProperties(Properties props) { |
| if (initLevel() != 0) |
| throw new IllegalStateException("Wrong init level"); |
| |
| @SuppressWarnings({"rawtypes", "unchecked"}) |
| Map<String, String> sp = |
| Map.ofEntries(props.entrySet().toArray(new Map.Entry[0])); |
| // only main thread is running at this time, so savedProps and |
| // its content will be correctly published to threads started later |
| savedProps = sp; |
| |
| // Set the maximum amount of direct memory. This value is controlled |
| // by the vm option -XX:MaxDirectMemorySize=<size>. |
| // The maximum amount of allocatable direct buffer memory (in bytes) |
| // from the system property sun.nio.MaxDirectMemorySize set by the VM. |
| // The system property will be removed. |
| String s = (String)props.remove("sun.nio.MaxDirectMemorySize"); |
| if (s != null) { |
| if (s.equals("-1")) { |
| // -XX:MaxDirectMemorySize not given, take default |
| directMemory = Runtime.getRuntime().maxMemory(); |
| } else { |
| long l = Long.parseLong(s); |
| if (l > -1) |
| directMemory = l; |
| } |
| } |
| |
| // Check if direct buffers should be page aligned |
| s = (String)props.remove("sun.nio.PageAlignDirectMemory"); |
| if ("true".equals(s)) |
| pageAlignDirectMemory = true; |
| |
| // Remove other private system properties |
| // used by java.lang.Integer.IntegerCache |
| props.remove("java.lang.Integer.IntegerCache.high"); |
| |
| // used by sun.launcher.LauncherHelper |
| props.remove("sun.java.launcher.diag"); |
| |
| // used by jdk.internal.loader.ClassLoaders |
| props.remove("jdk.boot.class.path.append"); |
| } |
| |
| // Initialize any miscellaneous operating system settings that need to be |
| // set for the class libraries. |
| // |
| public static void initializeOSEnvironment() { |
| if (initLevel() == 0) { |
| OSEnvironment.initialize(); |
| } |
| } |
| |
| /* Current count of objects pending for finalization */ |
| private static volatile int finalRefCount; |
| |
| /* Peak count of objects pending for finalization */ |
| private static volatile int peakFinalRefCount; |
| |
| /* |
| * Gets the number of objects pending for finalization. |
| * |
| * @return the number of objects pending for finalization. |
| */ |
| public static int getFinalRefCount() { |
| return finalRefCount; |
| } |
| |
| /* |
| * Gets the peak number of objects pending for finalization. |
| * |
| * @return the peak number of objects pending for finalization. |
| */ |
| public static int getPeakFinalRefCount() { |
| return peakFinalRefCount; |
| } |
| |
| /* |
| * Add {@code n} to the objects pending for finalization count. |
| * |
| * @param n an integer value to be added to the objects pending |
| * for finalization count |
| */ |
| public static void addFinalRefCount(int n) { |
| // The caller must hold lock to synchronize the update. |
| |
| finalRefCount += n; |
| if (finalRefCount > peakFinalRefCount) { |
| peakFinalRefCount = finalRefCount; |
| } |
| } |
| |
| /** |
| * Returns Thread.State for the given threadStatus |
| */ |
| public static Thread.State toThreadState(int threadStatus) { |
| if ((threadStatus & JVMTI_THREAD_STATE_RUNNABLE) != 0) { |
| return RUNNABLE; |
| } else if ((threadStatus & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER) != 0) { |
| return BLOCKED; |
| } else if ((threadStatus & JVMTI_THREAD_STATE_WAITING_INDEFINITELY) != 0) { |
| return WAITING; |
| } else if ((threadStatus & JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT) != 0) { |
| return TIMED_WAITING; |
| } else if ((threadStatus & JVMTI_THREAD_STATE_TERMINATED) != 0) { |
| return TERMINATED; |
| } else if ((threadStatus & JVMTI_THREAD_STATE_ALIVE) == 0) { |
| return NEW; |
| } else { |
| return RUNNABLE; |
| } |
| } |
| |
| /* The threadStatus field is set by the VM at state transition |
| * in the hotspot implementation. Its value is set according to |
| * the JVM TI specification GetThreadState function. |
| */ |
| private static final int JVMTI_THREAD_STATE_ALIVE = 0x0001; |
| private static final int JVMTI_THREAD_STATE_TERMINATED = 0x0002; |
| private static final int JVMTI_THREAD_STATE_RUNNABLE = 0x0004; |
| private static final int JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER = 0x0400; |
| private static final int JVMTI_THREAD_STATE_WAITING_INDEFINITELY = 0x0010; |
| private static final int JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT = 0x0020; |
| |
| /* |
| * Returns the first user-defined class loader up the execution stack, |
| * or the platform class loader if only code from the platform or |
| * bootstrap class loader is on the stack. |
| */ |
| public static ClassLoader latestUserDefinedLoader() { |
| ClassLoader loader = latestUserDefinedLoader0(); |
| return loader != null ? loader : ClassLoader.getPlatformClassLoader(); |
| } |
| |
| /* |
| * Returns the first user-defined class loader up the execution stack, |
| * or null if only code from the platform or bootstrap class loader is |
| * on the stack. VM does not keep a reference of platform loader and so |
| * it returns null. |
| * |
| * This method should be replaced with StackWalker::walk and then we can |
| * remove the logic in the VM. |
| */ |
| private static native ClassLoader latestUserDefinedLoader0(); |
| |
| /** |
| * Returns {@code true} if we are in a set UID program. |
| */ |
| public static boolean isSetUID() { |
| long uid = getuid(); |
| long euid = geteuid(); |
| long gid = getgid(); |
| long egid = getegid(); |
| return uid != euid || gid != egid; |
| } |
| |
| /** |
| * Returns the real user ID of the calling process, |
| * or -1 if the value is not available. |
| */ |
| public static native long getuid(); |
| |
| /** |
| * Returns the effective user ID of the calling process, |
| * or -1 if the value is not available. |
| */ |
| public static native long geteuid(); |
| |
| /** |
| * Returns the real group ID of the calling process, |
| * or -1 if the value is not available. |
| */ |
| public static native long getgid(); |
| |
| /** |
| * Returns the effective group ID of the calling process, |
| * or -1 if the value is not available. |
| */ |
| public static native long getegid(); |
| |
| /** |
| * Get a nanosecond time stamp adjustment in the form of a single long. |
| * |
| * This value can be used to create an instant using |
| * {@link java.time.Instant#ofEpochSecond(long, long) |
| * java.time.Instant.ofEpochSecond(offsetInSeconds, |
| * getNanoTimeAdjustment(offsetInSeconds))}. |
| * <p> |
| * The value returned has the best resolution available to the JVM on |
| * the current system. |
| * This is usually down to microseconds - or tenth of microseconds - |
| * depending on the OS/Hardware and the JVM implementation. |
| * |
| * @param offsetInSeconds The offset in seconds from which the nanosecond |
| * time stamp should be computed. |
| * |
| * @apiNote The offset should be recent enough - so that |
| * {@code offsetInSeconds} is within {@code +/- 2^32} seconds of the |
| * current UTC time. If the offset is too far off, {@code -1} will be |
| * returned. As such, {@code -1} must not be considered as a valid |
| * nano time adjustment, but as an exception value indicating |
| * that an offset closer to the current time should be used. |
| * |
| * @return A nanosecond time stamp adjustment in the form of a single long. |
| * If the offset is too far off the current time, this method returns -1. |
| * In that case, the caller should call this method again, passing a |
| * more accurate offset. |
| */ |
| public static native long getNanoTimeAdjustment(long offsetInSeconds); |
| |
| /** |
| * Returns the VM arguments for this runtime environment. |
| * |
| * @implNote |
| * The HotSpot JVM processes the input arguments from multiple sources |
| * in the following order: |
| * 1. JAVA_TOOL_OPTIONS environment variable |
| * 2. Options from JNI Invocation API |
| * 3. _JAVA_OPTIONS environment variable |
| * |
| * If VM options file is specified via -XX:VMOptionsFile, the vm options |
| * file is read and expanded in place of -XX:VMOptionFile option. |
| */ |
| public static native String[] getRuntimeArguments(); |
| |
| static { |
| initialize(); |
| } |
| private static native void initialize(); |
| } |