filemap.hpp revision 3465:d2a62e0f25eb 
1/*
2 * Copyright (c) 2003, 2010, 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.
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23 */
24
25#ifndef SHARE_VM_MEMORY_FILEMAP_HPP
26#define SHARE_VM_MEMORY_FILEMAP_HPP
27
28#include "memory/compactingPermGenGen.hpp"
29#include "memory/space.hpp"
30
31// Layout of the file:
32//  header: dump of archive instance plus versioning info, datestamp, etc.
33//   [magic # = 0xF00BABA2]
34//  ... padding to align on page-boundary
35//  read-write space from CompactingPermGenGen
36//  read-only space from CompactingPermGenGen
37//  misc data (block offset table, string table, symbols, dictionary, etc.)
38//  tag(666)
39
40static const int JVM_SHARED_JARS_MAX = 128;
41static const int JVM_SPACENAME_MAX = 128;
42static const int JVM_IDENT_MAX = 256;
43static const int JVM_ARCH_MAX = 12;
44
45
46
47class FileMapInfo : public CHeapObj<mtInternal> {
48private:
49  enum {
50    _invalid_version = -1,
51    _current_version = 1
52  };
53
54  bool  _file_open;
55  int   _fd;
56  long  _file_offset;
57
58  // FileMapHeader describes the shared space data in the file to be
59  // mapped.  This structure gets written to a file.  It is not a class, so
60  // that the compilers don't add any compiler-private data to it.
61
62  struct FileMapHeader {
63    int    _magic;                    // identify file type.
64    int    _version;                  // (from enum, above.)
65    size_t _alignment;                // how shared archive should be aligned
66
67    struct space_info {
68      int    _file_offset;   // sizeof(this) rounded to vm page size
69      char*  _base;          // copy-on-write base address
70      size_t _capacity;      // for validity checking
71      size_t _used;          // for setting space top on read
72      bool   _read_only;     // read only space?
73      bool   _allow_exec;    // executable code in space?
74    } _space[CompactingPermGenGen::n_regions];
75
76    // The following fields are all sanity checks for whether this archive
77    // will function correctly with this JVM and the bootclasspath it's
78    // invoked with.
79    char  _arch[JVM_ARCH_MAX];            // architecture
80    char  _jvm_ident[JVM_IDENT_MAX];      // identifier for jvm
81    int   _num_jars;              // Number of jars in bootclasspath
82
83    // Per jar file data:  timestamp, size.
84
85    struct {
86      time_t _timestamp;          // jar timestamp.
87      long   _filesize;           // jar file size.
88    } _jar[JVM_SHARED_JARS_MAX];
89  } _header;
90  const char* _full_path;
91
92  static FileMapInfo* _current_info;
93
94  bool  init_from_file(int fd);
95  void  align_file_position();
96
97public:
98  FileMapInfo() {
99    _file_offset = 0;
100    _file_open = false;
101    _header._version = _invalid_version;
102  }
103
104  static int current_version()        { return _current_version; }
105  void   populate_header(size_t alignment);
106  bool   validate();
107  void   invalidate();
108  int    version()                    { return _header._version; }
109  size_t alignment()                  { return _header._alignment; }
110  size_t space_capacity(int i)        { return _header._space[i]._capacity; }
111  char*  region_base(int i)           { return _header._space[i]._base; }
112  struct FileMapHeader* header()      { return &_header; }
113
114  static void set_current_info(FileMapInfo* info)  { _current_info = info; }
115  static FileMapInfo* current_info()  { return _current_info; }
116  static void assert_mark(bool check);
117
118  // File manipulation.
119  bool  initialize();
120  bool  open_for_read();
121  void  open_for_write();
122  void  write_header();
123  void  write_space(int i, CompactibleSpace* space, bool read_only);
124  void  write_region(int region, char* base, size_t size,
125                     size_t capacity, bool read_only, bool allow_exec);
126  void  write_bytes(const void* buffer, int count);
127  void  write_bytes_aligned(const void* buffer, int count);
128  bool  map_space(int i, ReservedSpace rs, ContiguousSpace *space);
129  char* map_region(int i, ReservedSpace rs);
130  char* map_region(int i, bool address_must_match);
131  void  unmap_region(int i);
132  void  close();
133  bool  is_open() { return _file_open; }
134
135  // JVM/TI RedefineClasses() support:
136  // Remap the shared readonly space to shared readwrite, private.
137  bool  remap_shared_readonly_as_readwrite();
138
139  // Errors.
140  static void fail_stop(const char *msg, ...);
141  void fail_continue(const char *msg, ...);
142
143  // Return true if given address is in the mapped shared space.
144  bool is_in_shared_space(const void* p);
145};
146
147#endif // SHARE_VM_MEMORY_FILEMAP_HPP
148