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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 | } | ||