1 /*
   2  * Copyright (c) 2018, 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  */
  24 
  25 #ifndef SHARE_INCLUDE_CDS_H
  26 #define SHARE_INCLUDE_CDS_H
  27 
  28 // This file declares the CDS data structures that are used by the HotSpot Serviceability Agent
  29 // (see C sources inside src/jdk.hotspot.agent).
  30 //
  31 // We should use only standard C types. Do not use custom types such as bool, intx,
  32 // etc, to avoid introducing unnecessary dependencies to other HotSpot type declarations.
  33 //
  34 // Also, this is a C header file. Do not use C++ here.
  35 
  36 #define NUM_CDS_REGIONS 8
  37 #define CDS_ARCHIVE_MAGIC 0xf00baba2
  38 #define CDS_DYNAMIC_ARCHIVE_MAGIC 0xf00baba8
  39 #define CDS_END_MAGIC     0xf00babae
  40 #define CURRENT_CDS_ARCHIVE_VERSION 6
  41 #define INVALID_CDS_ARCHIVE_VERSION -1
  42 
  43 #define JVM_IDENT_MAX 256
  44 
  45 struct CDSFileMapRegion {
  46   int        _crc;           // crc checksum of the current space
  47   size_t     _file_offset;   // sizeof(this) rounded to vm page size
  48   union {
  49     char*    _base;          // copy-on-write base address
  50     size_t   _offset;        // offset from the compressed oop encoding base, only used
  51                              // by archive heap space
  52   } _addr;
  53   size_t     _used;          // for setting space top on read
  54   int        _read_only;     // read only space?
  55   int        _allow_exec;    // executable code in space?
  56   void*      _oopmap;        // bitmap for relocating embedded oops
  57   size_t     _oopmap_size_in_bits;
  58 };
  59 
  60 struct CDSFileMapHeaderBase {
  61   unsigned int _magic;             // identify file type
  62   int          _crc;               // header crc checksum
  63   int          _version;           // must be CURRENT_CDS_ARCHIVE_VERSION
  64   char  _jvm_ident[JVM_IDENT_MAX]; // identifier of the JVM with which this archive was generated
  65   unsigned int _end_magic;         // fixed identifier following _jvm_ident
  66   struct CDSFileMapRegion _space[NUM_CDS_REGIONS];
  67 };
  68 
  69 typedef struct CDSFileMapHeaderBase CDSFileMapHeaderBase;
  70 
  71 #endif // SHARE_INCLUDE_CDS_H