J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2004 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any 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 | } |