1 /*
2 * Copyright (c) 2003, 2013, 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_VM_MEMORY_FILEMAP_HPP
26 #define SHARE_VM_MEMORY_FILEMAP_HPP
27
28 #include "memory/metaspaceShared.hpp"
29
30 // Layout of the file:
31 // header: dump of archive instance plus versioning info, datestamp, etc.
32 // [magic # = 0xF00BABA2]
33 // ... padding to align on page-boundary
34 // read-write space from CompactingPermGenGen
35 // read-only space from CompactingPermGenGen
36 // misc data (block offset table, string table, symbols, dictionary, etc.)
37 // tag(666)
38
39 static const int JVM_SHARED_JARS_MAX = 128;
40 static const int JVM_SPACENAME_MAX = 128;
41 static const int JVM_IDENT_MAX = 256;
42 static const int JVM_ARCH_MAX = 12;
43
44
45 class Metaspace;
46
47 class FileMapInfo : public CHeapObj<mtInternal> {
48 private:
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 int _obj_alignment; // value of ObjectAlignmentInBytes
67
68 struct space_info {
69 int _file_offset; // sizeof(this) rounded to vm page size
70 char* _base; // copy-on-write base address
71 size_t _capacity; // for validity checking
72 size_t _used; // for setting space top on read
73 bool _read_only; // read only space?
74 bool _allow_exec; // executable code in space?
75 } _space[MetaspaceShared::n_regions];
76
77 // The following fields are all sanity checks for whether this archive
78 // will function correctly with this JVM and the bootclasspath it's
79 // invoked with.
80 char _arch[JVM_ARCH_MAX]; // architecture
81 char _jvm_ident[JVM_IDENT_MAX]; // identifier for jvm
82 int _num_jars; // Number of jars in bootclasspath
83
84 // Per jar file data: timestamp, size.
85
86 struct {
87 time_t _timestamp; // jar timestamp.
88 long _filesize; // jar file size.
89 } _jar[JVM_SHARED_JARS_MAX];
90 } _header;
91 const char* _full_path;
92
93 static FileMapInfo* _current_info;
94
95 bool init_from_file(int fd);
96 void align_file_position();
97
98 public:
99 FileMapInfo() {
100 _file_offset = 0;
101 _file_open = false;
102 _header._version = _invalid_version;
103 }
104
105 static int current_version() { return _current_version; }
106 void populate_header(size_t alignment);
107 bool validate();
108 void invalidate();
109 int version() { return _header._version; }
110 size_t alignment() { return _header._alignment; }
111 size_t space_capacity(int i) { return _header._space[i]._capacity; }
112 char* region_base(int i) { return _header._space[i]._base; }
113 struct FileMapHeader* header() { return &_header; }
114
115 static void set_current_info(FileMapInfo* info) {
116 CDS_ONLY(_current_info = info;)
117 }
118
119 static FileMapInfo* current_info() {
120 CDS_ONLY(return _current_info;)
121 NOT_CDS(return NULL;)
122 }
123
124 static void assert_mark(bool check);
125
126 // File manipulation.
127 bool initialize() NOT_CDS_RETURN_(false);
128 bool open_for_read();
129 void open_for_write();
130 void write_header();
131 void write_space(int i, Metaspace* space, bool read_only);
132 void write_region(int region, char* base, size_t size,
133 size_t capacity, bool read_only, bool allow_exec);
134 void write_bytes(const void* buffer, int count);
135 void write_bytes_aligned(const void* buffer, int count);
136 char* map_region(int i);
137 void unmap_region(int i);
138 void close();
139 bool is_open() { return _file_open; }
140 ReservedSpace reserve_shared_memory();
141
142 // JVM/TI RedefineClasses() support:
143 // Remap the shared readonly space to shared readwrite, private.
144 bool remap_shared_readonly_as_readwrite();
145
146 // Errors.
147 static void fail_stop(const char *msg, ...);
148 void fail_continue(const char *msg, ...);
149
150 // Return true if given address is in the mapped shared space.
151 bool is_in_shared_space(const void* p) NOT_CDS_RETURN_(false);
152 void print_shared_spaces() NOT_CDS_RETURN;
153
154 static size_t shared_spaces_size() {
155 return align_size_up(SharedReadOnlySize + SharedReadWriteSize +
156 SharedMiscDataSize + SharedMiscCodeSize,
157 os::vm_allocation_granularity());
158 }
159
160 // Stop CDS sharing and unmap CDS regions.
161 static void stop_sharing_and_unmap(const char* msg);
162 };
163
164 #endif // SHARE_VM_MEMORY_FILEMAP_HPP