1 /* 2 * Copyright (c) 2014, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package jdk.vm.ci.services; 24 25 import java.io.ByteArrayInputStream; 26 import java.io.ByteArrayOutputStream; 27 import java.io.DataInputStream; 28 import java.io.DataOutputStream; 29 import java.io.IOException; 30 import java.util.ArrayList; 31 import java.util.Collections; 32 import java.util.Formatter; 33 import java.util.HashMap; 34 import java.util.List; 35 import java.util.Map; 36 import java.util.ServiceLoader; 37 import java.util.Set; 38 39 import jdk.internal.misc.VM; 40 41 /** 42 * Provides utilities needed by JVMCI clients. 43 */ 44 public final class Services { 45 46 /** 47 * Guards code that should be run when building an JVMCI shared library but should be excluded 48 * from (being compiled into) the library. Such code must be directly guarded by an {@code if} 49 * statement on this field - the guard cannot be behind a method call. 50 */ 51 public static final boolean IS_BUILDING_NATIVE_IMAGE = Boolean.parseBoolean(VM.getSavedProperty("jdk.vm.ci.services.aot")); 52 53 /** 54 * Guards code that should only be run in a JVMCI shared library. Such code must be directly 55 * guarded by an {@code if} statement on this field - the guard cannot be behind a method call. 56 * 57 * The value of this field in a JVMCI shared library runtime must be {@code true}. 58 */ 59 public static final boolean IS_IN_NATIVE_IMAGE; 60 static { 61 /* 62 * Prevents javac from constant folding use of this field. It is set to true by the process 63 * that builds the shared library. 64 */ 65 IS_IN_NATIVE_IMAGE = false; 66 } 67 Services()68 private Services() { 69 } 70 71 /** 72 * In a native image, this field is initialized by {@link #initializeSavedProperties(byte[])}. 73 */ 74 private static volatile Map<String, String> savedProperties; 75 76 static final boolean JVMCI_ENABLED = Boolean.parseBoolean(VM.getSavedProperties().get("jdk.internal.vm.ci.enabled")); 77 78 /** 79 * Checks that JVMCI is enabled in the VM and throws an error if it isn't. 80 */ checkJVMCIEnabled()81 static void checkJVMCIEnabled() { 82 if (!JVMCI_ENABLED) { 83 throw new Error("The EnableJVMCI VM option must be true (i.e., -XX:+EnableJVMCI) to use JVMCI"); 84 } 85 } 86 87 /** 88 * Gets an unmodifiable copy of the system properties saved when {@link System} is initialized. 89 */ getSavedProperties()90 public static Map<String, String> getSavedProperties() { 91 checkJVMCIEnabled(); 92 if (IS_IN_NATIVE_IMAGE) { 93 if (savedProperties == null) { 94 throw new InternalError("Saved properties not initialized"); 95 } 96 } else { 97 if (savedProperties == null) { 98 synchronized (Services.class) { 99 if (savedProperties == null) { 100 SecurityManager sm = System.getSecurityManager(); 101 if (sm != null) { 102 sm.checkPermission(new JVMCIPermission()); 103 } 104 savedProperties = VM.getSavedProperties(); 105 } 106 } 107 } 108 } 109 return savedProperties; 110 } 111 112 /** 113 * Helper method equivalent to {@link #getSavedProperties()}{@code .getOrDefault(name, def)}. 114 */ getSavedProperty(String name, String def)115 public static String getSavedProperty(String name, String def) { 116 return Services.getSavedProperties().getOrDefault(name, def); 117 } 118 119 /** 120 * Helper method equivalent to {@link #getSavedProperties()}{@code .get(name)}. 121 */ getSavedProperty(String name)122 public static String getSavedProperty(String name) { 123 return Services.getSavedProperties().get(name); 124 } 125 126 /** 127 * Causes the JVMCI subsystem to be initialized if it isn't already initialized. 128 */ initializeJVMCI()129 public static void initializeJVMCI() { 130 checkJVMCIEnabled(); 131 try { 132 Class.forName("jdk.vm.ci.runtime.JVMCI"); 133 } catch (ClassNotFoundException e) { 134 throw new InternalError(e); 135 } 136 } 137 138 private static final Map<Class<?>, List<?>> servicesCache = IS_BUILDING_NATIVE_IMAGE ? new HashMap<>() : null; 139 140 @SuppressWarnings("unchecked") load0(Class<S> service)141 private static <S> Iterable<S> load0(Class<S> service) { 142 if (IS_IN_NATIVE_IMAGE || IS_BUILDING_NATIVE_IMAGE) { 143 List<?> list = servicesCache.get(service); 144 if (list != null) { 145 return (Iterable<S>) list; 146 } 147 if (IS_IN_NATIVE_IMAGE) { 148 throw new InternalError(String.format("No %s providers found when building native image", service.getName())); 149 } 150 } 151 152 Iterable<S> providers = ServiceLoader.load(service, ClassLoader.getSystemClassLoader()); 153 if (IS_BUILDING_NATIVE_IMAGE) { 154 synchronized (servicesCache) { 155 ArrayList<S> providersList = new ArrayList<>(); 156 for (S provider : providers) { 157 providersList.add(provider); 158 } 159 servicesCache.put(service, providersList); 160 providers = providersList; 161 } 162 } 163 return providers; 164 } 165 166 /** 167 * Opens all JVMCI packages to {@code otherModule}. 168 */ openJVMCITo(Module otherModule)169 static void openJVMCITo(Module otherModule) { 170 Module jvmci = Services.class.getModule(); 171 if (jvmci != otherModule) { 172 Set<String> packages = jvmci.getPackages(); 173 for (String pkg : packages) { 174 boolean opened = jvmci.isOpen(pkg, otherModule); 175 if (!opened) { 176 jvmci.addOpens(pkg, otherModule); 177 } 178 } 179 } 180 } 181 182 /** 183 * Gets an {@link Iterable} of the JVMCI providers available for a given service. 184 * 185 * @throws SecurityException if a security manager is present and it denies <tt> 186 * {@link RuntimePermission}("jvmci")</tt> 187 */ load(Class<S> service)188 public static <S> Iterable<S> load(Class<S> service) { 189 SecurityManager sm = System.getSecurityManager(); 190 if (sm != null) { 191 sm.checkPermission(new JVMCIPermission()); 192 } 193 return load0(service); 194 } 195 196 /** 197 * Gets the JVMCI provider for a given service for which at most one provider must be available. 198 * 199 * @param service the service whose provider is being requested 200 * @param required specifies if an {@link InternalError} should be thrown if no provider of 201 * {@code service} is available 202 * @throws SecurityException if a security manager is present and it denies <tt> 203 * {@link RuntimePermission}("jvmci")</tt> 204 */ loadSingle(Class<S> service, boolean required)205 public static <S> S loadSingle(Class<S> service, boolean required) { 206 SecurityManager sm = System.getSecurityManager(); 207 if (sm != null) { 208 sm.checkPermission(new JVMCIPermission()); 209 } 210 Iterable<S> providers = load0(service); 211 212 S singleProvider = null; 213 for (S provider : providers) { 214 if (singleProvider != null) { 215 throw new InternalError(String.format("Multiple %s providers found: %s, %s", service.getName(), singleProvider.getClass().getName(), provider.getClass().getName())); 216 } 217 singleProvider = provider; 218 } 219 if (singleProvider == null && required) { 220 String javaHome = Services.getSavedProperty("java.home"); 221 String vmName = Services.getSavedProperty("java.vm.name"); 222 Formatter errorMessage = new Formatter(); 223 errorMessage.format("The VM does not expose required service %s.%n", service.getName()); 224 errorMessage.format("Currently used Java home directory is %s.%n", javaHome); 225 errorMessage.format("Currently used VM configuration is: %s", vmName); 226 throw new UnsupportedOperationException(errorMessage.toString()); 227 } 228 return singleProvider; 229 } 230 231 /** 232 * A Java {@code char} has a maximal UTF8 length of 3. 233 */ 234 private static final int MAX_UNICODE_IN_UTF8_LENGTH = 3; 235 236 /** 237 * {@link DataOutputStream#writeUTF(String)} only supports values whose UTF8 encoding length is 238 * less than 65535. 239 */ 240 private static final int MAX_UTF8_PROPERTY_STRING_LENGTH = 65535 / MAX_UNICODE_IN_UTF8_LENGTH; 241 242 /** 243 * Serializes the {@linkplain #getSavedProperties() saved system properties} to a byte array for 244 * the purpose of {@linkplain #initializeSavedProperties(byte[]) initializing} the initial 245 * properties in the JVMCI shared library. 246 */ 247 @VMEntryPoint serializeSavedProperties()248 private static byte[] serializeSavedProperties() throws IOException { 249 if (IS_IN_NATIVE_IMAGE) { 250 throw new InternalError("Can only serialize saved properties in HotSpot runtime"); 251 } 252 return serializeProperties(Services.getSavedProperties()); 253 } 254 serializeProperties(Map<String, String> props)255 private static byte[] serializeProperties(Map<String, String> props) throws IOException { 256 // Compute size of output on the assumption that 257 // all system properties have ASCII names and values 258 int estimate = 4 + 4; 259 int nonUtf8Props = 0; 260 for (Map.Entry<String, String> e : props.entrySet()) { 261 String name = e.getKey(); 262 String value = e.getValue(); 263 estimate += (2 + (name.length())) + (2 + (value.length())); 264 if (name.length() > MAX_UTF8_PROPERTY_STRING_LENGTH || value.length() > MAX_UTF8_PROPERTY_STRING_LENGTH) { 265 nonUtf8Props++; 266 } 267 } 268 269 ByteArrayOutputStream baos = new ByteArrayOutputStream(estimate); 270 DataOutputStream out = new DataOutputStream(baos); 271 out.writeInt(props.size() - nonUtf8Props); 272 out.writeInt(nonUtf8Props); 273 for (Map.Entry<String, String> e : props.entrySet()) { 274 String name = e.getKey(); 275 String value = e.getValue(); 276 if (name.length() <= MAX_UTF8_PROPERTY_STRING_LENGTH && value.length() <= MAX_UTF8_PROPERTY_STRING_LENGTH) { 277 out.writeUTF(name); 278 out.writeUTF(value); 279 } 280 } 281 if (nonUtf8Props != 0) { 282 for (Map.Entry<String, String> e : props.entrySet()) { 283 String name = e.getKey(); 284 String value = e.getValue(); 285 if (name.length() > MAX_UTF8_PROPERTY_STRING_LENGTH || value.length() > MAX_UTF8_PROPERTY_STRING_LENGTH) { 286 byte[] utf8Name = name.getBytes("UTF-8"); 287 byte[] utf8Value = value.getBytes("UTF-8"); 288 out.writeInt(utf8Name.length); 289 out.write(utf8Name); 290 out.writeInt(utf8Value.length); 291 out.write(utf8Value); 292 } 293 } 294 } 295 return baos.toByteArray(); 296 } 297 298 /** 299 * Initialized the {@linkplain #getSavedProperties() saved system properties} in the JVMCI 300 * shared library from the {@linkplain #serializeSavedProperties() serialized saved properties} 301 * in the HotSpot runtime. 302 */ 303 @VMEntryPoint initializeSavedProperties(byte[] serializedProperties)304 private static void initializeSavedProperties(byte[] serializedProperties) throws IOException { 305 if (!IS_IN_NATIVE_IMAGE) { 306 throw new InternalError("Can only initialize saved properties in JVMCI shared library runtime"); 307 } 308 savedProperties = Collections.unmodifiableMap(deserializeProperties(serializedProperties)); 309 } 310 deserializeProperties(byte[] serializedProperties)311 private static Map<String, String> deserializeProperties(byte[] serializedProperties) throws IOException { 312 DataInputStream in = new DataInputStream(new ByteArrayInputStream(serializedProperties)); 313 int utf8Props = in.readInt(); 314 int nonUtf8Props = in.readInt(); 315 Map<String, String> props = new HashMap<>(utf8Props + nonUtf8Props); 316 int index = 0; 317 while (in.available() != 0) { 318 if (index < utf8Props) { 319 String name = in.readUTF(); 320 String value = in.readUTF(); 321 props.put(name, value); 322 } else { 323 int nameLen = in.readInt(); 324 byte[] nameBytes = new byte[nameLen]; 325 in.read(nameBytes); 326 int valueLen = in.readInt(); 327 byte[] valueBytes = new byte[valueLen]; 328 in.read(valueBytes); 329 String name = new String(nameBytes, "UTF-8"); 330 String value = new String(valueBytes, "UTF-8"); 331 props.put(name, value); 332 } 333 index++; 334 } 335 return props; 336 } 337 } 338