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| 1 | +/* | |
| 2 | + * Copyright (c) 2004, 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. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package sun.jvmstat.perfdata.monitor; | |
| 27 | + | |
| 28 | +import sun.jvmstat.monitor.*; | |
| 29 | +import java.nio.ByteOrder; | |
| 30 | +import java.nio.ByteBuffer; | |
| 31 | +import java.nio.IntBuffer; | |
| 32 | + | |
| 33 | +/** | |
| 34 | + * Abstraction representing the HotSpot PerfData instrumentation buffer | |
| 35 | + * header. This class represents only the fixed portion of the header. | |
| 36 | + * Version specific classes represent the portion of the header that | |
| 37 | + * may change from release to release. | |
| 38 | + * <p> | |
| 39 | + * The PerfDataBufferProlog class supports parsing of the following | |
| 40 | + * C structure: | |
| 41 | + * <pre> | |
| 42 | + * typedef struct { | |
| 43 | + * jint magic; // magic number - 0xcafec0c0 | |
| 44 | + * jbyte byte_order; // byte order of the buffer | |
| 45 | + * jbyte major_version; // major and minor version numbers | |
| 46 | + * jbyte minor_version; | |
| 47 | + * jbyte reserved_byte1; // reserved - see concrete implementations for | |
| 48 | + * // possible definition. | |
| 49 | + * ... // remainder is handled by the subclasses. | |
| 50 | + * } PerfDataPrologue | |
| 51 | + * </pre> | |
| 52 | + * | |
| 53 | + * @author Brian Doherty | |
| 54 | + * @since 1.5 | |
| 55 | + */ | |
| 56 | +public abstract class AbstractPerfDataBufferPrologue { | |
| 57 | + | |
| 58 | + protected ByteBuffer byteBuffer; | |
| 59 | + | |
| 60 | + /* | |
| 61 | + * the following constants must match the field offsets and sizes | |
| 62 | + * in the PerfDataPrologue structure in perfMemory.hpp | |
| 63 | + */ | |
| 64 | + final static int PERFDATA_PROLOG_OFFSET=0; | |
| 65 | + final static int PERFDATA_PROLOG_MAGIC_OFFSET=0; | |
| 66 | + final static int PERFDATA_PROLOG_BYTEORDER_OFFSET=4; | |
| 67 | + final static int PERFDATA_PROLOG_BYTEORDER_SIZE=1; // sizeof(byte) | |
| 68 | + final static int PERFDATA_PROLOG_MAJOR_OFFSET=5; | |
| 69 | + final static int PERFDATA_PROLOG_MAJOR_SIZE=1; // sizeof(byte) | |
| 70 | + final static int PERFDATA_PROLOG_MINOR_OFFSET=6; | |
| 71 | + final static int PERFDATA_PROLOG_MINOR_SIZE=1; // sizeof(byte) | |
| 72 | + final static int PERFDATA_PROLOG_RESERVEDB1_OFFSET=7; | |
| 73 | + final static int PERFDATA_PROLOG_RESERVEDB1_SIZE=1; // sizeof(byte) | |
| 74 | + | |
| 75 | + final static int PERFDATA_PROLOG_SIZE=8; // sizeof(struct PerfDataProlog) | |
| 76 | + | |
| 77 | + // these constants should match their #define counterparts in perfMemory.hpp | |
| 78 | + final static byte PERFDATA_BIG_ENDIAN=0; | |
| 79 | + final static byte PERFDATA_LITTLE_ENDIAN=1; | |
| 80 | + final static int PERFDATA_MAGIC = 0xcafec0c0; | |
| 81 | + | |
| 82 | + // names for counters that expose the prolog fields | |
| 83 | + public final static String PERFDATA_MAJOR_NAME = | |
| 84 | + "sun.perfdata.majorVersion"; | |
| 85 | + public final static String PERFDATA_MINOR_NAME = | |
| 86 | + "sun.perfdata.minorVersion"; | |
| 87 | + | |
| 88 | + /** | |
| 89 | + * Construct a PerfDataBufferPrologue instance. | |
| 90 | + * | |
| 91 | + * @param byteBuffer buffer containing the instrumentation data | |
| 92 | + */ | |
| 93 | + public AbstractPerfDataBufferPrologue(ByteBuffer byteBuffer) | |
| 94 | + throws MonitorException { | |
| 95 | + this.byteBuffer = byteBuffer.duplicate(); | |
| 96 | + | |
| 97 | + // the magic number is always stored in big-endian format | |
| 98 | + if (getMagic() != PERFDATA_MAGIC) { | |
| 99 | + throw new MonitorVersionException( | |
| 100 | + "Bad Magic: " + Integer.toHexString(getMagic())); | |
| 101 | + } | |
| 102 | + | |
| 103 | + // set the byte order | |
| 104 | + this.byteBuffer.order(getByteOrder()); | |
| 105 | + } | |
| 106 | + | |
| 107 | + /** | |
| 108 | + * Get the magic number. | |
| 109 | + * | |
| 110 | + * @return int - the magic number | |
| 111 | + */ | |
| 112 | + public int getMagic() { | |
| 113 | + // the magic number is always stored in big-endian format | |
| 114 | + ByteOrder order = byteBuffer.order(); | |
| 115 | + byteBuffer.order(ByteOrder.BIG_ENDIAN); | |
| 116 | + | |
| 117 | + // get the magic number | |
| 118 | + byteBuffer.position(PERFDATA_PROLOG_MAGIC_OFFSET); | |
| 119 | + int magic = byteBuffer.getInt(); | |
| 120 | + | |
| 121 | + // restore the byte order | |
| 122 | + byteBuffer.order(order); | |
| 123 | + return magic; | |
| 124 | + } | |
| 125 | + | |
| 126 | + /** | |
| 127 | + * Get the byte order. | |
| 128 | + * | |
| 129 | + * @return int - the byte order of the instrumentation buffer | |
| 130 | + */ | |
| 131 | + public ByteOrder getByteOrder() { | |
| 132 | + // byte order field is byte order independent | |
| 133 | + byteBuffer.position(PERFDATA_PROLOG_BYTEORDER_OFFSET); | |
| 134 | + | |
| 135 | + byte byte_order = byteBuffer.get(); | |
| 136 | + | |
| 137 | + if (byte_order == PERFDATA_BIG_ENDIAN) { | |
| 138 | + return ByteOrder.BIG_ENDIAN; | |
| 139 | + } else { | |
| 140 | + return ByteOrder.LITTLE_ENDIAN; | |
| 141 | + } | |
| 142 | + } | |
| 143 | + | |
| 144 | + /** | |
| 145 | + * Get the major version. | |
| 146 | + * | |
| 147 | + * @return int - the major version | |
| 148 | + */ | |
| 149 | + public int getMajorVersion() { | |
| 150 | + // major version field is byte order independent | |
| 151 | + byteBuffer.position(PERFDATA_PROLOG_MAJOR_OFFSET); | |
| 152 | + return (int)byteBuffer.get(); | |
| 153 | + } | |
| 154 | + | |
| 155 | + /** | |
| 156 | + * Get the minor version. | |
| 157 | + * | |
| 158 | + * @return int - the minor version | |
| 159 | + */ | |
| 160 | + public int getMinorVersion() { | |
| 161 | + // minor version field is byte order independent | |
| 162 | + byteBuffer.position(PERFDATA_PROLOG_MINOR_OFFSET); | |
| 163 | + return (int)byteBuffer.get(); | |
| 164 | + } | |
| 165 | + | |
| 166 | + /** | |
| 167 | + * Get the accessible flag. If supported, it indicates that the shared | |
| 168 | + * memory region is sufficiently initialized for client acccess. | |
| 169 | + * | |
| 170 | + * @return boolean - the initialized status | |
| 171 | + * @see #supportsAccessible() | |
| 172 | + */ | |
| 173 | + public abstract boolean isAccessible(); | |
| 174 | + | |
| 175 | + /** | |
| 176 | + * Test if the accessible flag is supported by this version of | |
| 177 | + * the PerfDataBufferPrologue. Although not an abstract method, this | |
| 178 | + * method should be overridden by version specific subclasses. | |
| 179 | + * | |
| 180 | + * @return boolean - the initialized flag support status. | |
| 181 | + * @see #isAccessible() | |
| 182 | + */ | |
| 183 | + public abstract boolean supportsAccessible(); | |
| 184 | + | |
| 185 | + /** | |
| 186 | + * Get the size of the header portion of the instrumentation buffer. | |
| 187 | + * | |
| 188 | + * @return int - the size of the header | |
| 189 | + */ | |
| 190 | + public int getSize() { | |
| 191 | + return PERFDATA_PROLOG_SIZE; // sizeof(struct PerfDataProlog) | |
| 192 | + } | |
| 193 | + | |
| 194 | + /** | |
| 195 | + * Return an IntBuffer that accesses the major version number. | |
| 196 | + * This is used to create a Monitor object for this value. | |
| 197 | + * | |
| 198 | + * @return IntBuffer - a ByteBuffer that accesses the major version number | |
| 199 | + * in the instrumentation buffer header. | |
| 200 | + */ | |
| 201 | + public IntBuffer majorVersionBuffer() { | |
| 202 | + int[] holder = new int[1]; | |
| 203 | + holder[0] = getMajorVersion(); | |
| 204 | + IntBuffer ib = IntBuffer.wrap(holder); | |
| 205 | + ib.limit(1); | |
| 206 | + return ib; | |
| 207 | + } | |
| 208 | + | |
| 209 | + /** | |
| 210 | + * Return an IntBuffer that accesses the minor version number. | |
| 211 | + * This is used to create a Monitor object for this value. | |
| 212 | + * | |
| 213 | + * @return IntBuffer - a ByteBuffer that accesses the minor version number | |
| 214 | + * in the instrumentation buffer header. | |
| 215 | + */ | |
| 216 | + public IntBuffer minorVersionBuffer() { | |
| 217 | + int[] holder = new int[1]; | |
| 218 | + holder[0] = getMinorVersion(); | |
| 219 | + IntBuffer ib = IntBuffer.wrap(holder); | |
| 220 | + ib.limit(1); | |
| 221 | + return ib; | |
| 222 | + } | |
| 223 | + | |
| 224 | + /** | |
| 225 | + * Get the magic number from the given byteBuffer. | |
| 226 | + * | |
| 227 | + * @return int - the magic number | |
| 228 | + */ | |
| 229 | + public static int getMagic(ByteBuffer bb) { | |
| 230 | + // save buffer state | |
| 231 | + int position = bb.position(); | |
| 232 | + ByteOrder order = bb.order(); | |
| 233 | + | |
| 234 | + // the magic number is always stored in big-endian format | |
| 235 | + bb.order(ByteOrder.BIG_ENDIAN); | |
| 236 | + bb.position(PERFDATA_PROLOG_MAGIC_OFFSET); | |
| 237 | + int magic = bb.getInt(); | |
| 238 | + | |
| 239 | + // restore buffer state. | |
| 240 | + bb.order(order); | |
| 241 | + bb.position(position); | |
| 242 | + | |
| 243 | + return magic; | |
| 244 | + } | |
| 245 | + | |
| 246 | + /** | |
| 247 | + * Get the major version number from the given ByteBuffer. | |
| 248 | + * | |
| 249 | + * @return int - the major version | |
| 250 | + */ | |
| 251 | + public static int getMajorVersion(ByteBuffer bb) { | |
| 252 | + // save buffer state | |
| 253 | + int position = bb.position(); | |
| 254 | + | |
| 255 | + bb.position(PERFDATA_PROLOG_MAJOR_OFFSET); | |
| 256 | + int major = (int) bb.get(); | |
| 257 | + | |
| 258 | + // restore buffer state. | |
| 259 | + bb.position(position); | |
| 260 | + | |
| 261 | + return major; | |
| 262 | + } | |
| 263 | + | |
| 264 | + /** | |
| 265 | + * Get the minor version number from the given ByteBuffer. | |
| 266 | + * | |
| 267 | + * @return int - the minor version | |
| 268 | + */ | |
| 269 | + public static int getMinorVersion(ByteBuffer bb) { | |
| 270 | + // save buffer state | |
| 271 | + int position = bb.position(); | |
| 272 | + | |
| 273 | + bb.position(PERFDATA_PROLOG_MINOR_OFFSET); | |
| 274 | + int minor = (int)bb.get(); | |
| 275 | + | |
| 276 | + // restore buffer state. | |
| 277 | + bb.position(position); | |
| 278 | + | |
| 279 | + return minor; | |
| 280 | + } | |
| 281 | + | |
| 282 | + /** | |
| 283 | + * Get the byte order for the given ByteBuffer. | |
| 284 | + * | |
| 285 | + * @return int - the byte order of the instrumentation buffer | |
| 286 | + */ | |
| 287 | + public static ByteOrder getByteOrder(ByteBuffer bb) { | |
| 288 | + // save buffer state | |
| 289 | + int position = bb.position(); | |
| 290 | + | |
| 291 | + bb.position(PERFDATA_PROLOG_BYTEORDER_OFFSET); | |
| 292 | + ByteOrder order = (bb.get() == PERFDATA_BIG_ENDIAN) | |
| 293 | + ? ByteOrder.BIG_ENDIAN | |
| 294 | + : ByteOrder.LITTLE_ENDIAN; | |
| 295 | + | |
| 296 | + // restore buffer state. | |
| 297 | + bb.position(position); | |
| 298 | + return order; | |
| 299 | + } | |
| 300 | +} | |