1 /*
2 * Copyright (c) 2003, 2014, 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 #include "memory/metaspace.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
36 // read-only space
37 // misc data (block offset table, string table, symbols, dictionary, etc.)
38 // tag(666)
39
40 static const int JVM_IDENT_MAX = 256;
41
42 class Metaspace;
43
44 class SharedClassPathEntry VALUE_OBJ_CLASS_SPEC {
45 public:
46 const char *_name;
47 time_t _timestamp; // jar timestamp, 0 if is directory or other
48 long _filesize; // jar file size, -1 if is directory, -2 if other
49 bool is_jar() {
50 return _timestamp != 0;
51 }
52 bool is_dir() {
53 return _filesize == -1;
54 }
55 };
56
57 class FileMapInfo : public CHeapObj<mtInternal> {
58 private:
59 friend class ManifestStream;
60 enum {
61 _invalid_version = -1,
62 _current_version = 2
63 };
64
65 bool _file_open;
66 int _fd;
67 size_t _file_offset;
68
69 private:
70 static SharedClassPathEntry* _classpath_entry_table;
71 static int _classpath_entry_table_size;
72 static size_t _classpath_entry_size;
73 static bool _validating_classpath_entry_table;
74
75 // FileMapHeader describes the shared space data in the file to be
76 // mapped. This structure gets written to a file. It is not a class, so
77 // that the compilers don't add any compiler-private data to it.
78
79 public:
80 struct FileMapHeaderBase : public CHeapObj<mtClass> {
81 virtual bool validate() = 0;
82 virtual void populate(FileMapInfo* info, size_t alignment) = 0;
83 };
84 struct FileMapHeader : FileMapHeaderBase {
85 // Use data() and data_size() to memcopy to/from the FileMapHeader. We need to
86 // avoid read/writing the C++ vtable pointer.
87 static size_t data_size();
88 char* data() {
89 return ((char*)this) + sizeof(FileMapHeaderBase);
90 }
91
92 int _magic; // identify file type.
93 int _crc; // header crc checksum.
94 int _version; // (from enum, above.)
95 size_t _alignment; // how shared archive should be aligned
96 int _obj_alignment; // value of ObjectAlignmentInBytes
97
98 struct space_info {
99 int _crc; // crc checksum of the current space
100 size_t _file_offset; // sizeof(this) rounded to vm page size
101 char* _base; // copy-on-write base address
102 size_t _capacity; // for validity checking
103 size_t _used; // for setting space top on read
104 bool _read_only; // read only space?
105 bool _allow_exec; // executable code in space?
106 } _space[MetaspaceShared::n_regions];
107
108 // The following fields are all sanity checks for whether this archive
109 // will function correctly with this JVM and the bootclasspath it's
110 // invoked with.
111 char _jvm_ident[JVM_IDENT_MAX]; // identifier for jvm
112
113 // The _paths_misc_info is a variable-size structure that records "miscellaneous"
114 // information during dumping. It is generated and validated by the
115 // SharedPathsMiscInfo class. See SharedPathsMiscInfo.hpp and sharedClassUtil.hpp for
116 // detailed description.
117 //
118 // The _paths_misc_info data is stored as a byte array in the archive file header,
119 // immediately after the _header field. This information is used only when
120 // checking the validity of the archive and is deallocated after the archive is loaded.
121 //
122 // Note that the _paths_misc_info does NOT include information for JAR files
123 // that existed during dump time. Their information is stored in _classpath_entry_table.
124 int _paths_misc_info_size;
125
126 // The following is a table of all the class path entries that were used
127 // during dumping. At run time, we require these files to exist and have the same
128 // size/modification time, or else the archive will refuse to load.
129 //
130 // All of these entries must be JAR files. The dumping process would fail if a non-empty
131 // directory was specified in the classpaths. If an empty directory was specified
132 // it is checked by the _paths_misc_info as described above.
133 //
134 // FIXME -- if JAR files in the tail of the list were specified but not used during dumping,
135 // they should be removed from this table, to save space and to avoid spurious
136 // loading failures during runtime.
137 int _classpath_entry_table_size;
138 size_t _classpath_entry_size;
139 SharedClassPathEntry* _classpath_entry_table;
140
141 virtual bool validate();
142 virtual void populate(FileMapInfo* info, size_t alignment);
143 int compute_crc();
144 };
145
146 FileMapHeader * _header;
147
148 const char* _full_path;
149 char* _paths_misc_info;
150
151 static FileMapInfo* _current_info;
152
153 bool init_from_file(int fd);
154 void align_file_position();
155 bool validate_header_impl();
156
157 public:
158 FileMapInfo();
159 ~FileMapInfo();
160
161 static int current_version() { return _current_version; }
162 int compute_header_crc() { return _header->compute_crc(); }
163 void set_header_crc(int crc) { _header->_crc = crc; }
164 void populate_header(size_t alignment);
165 bool validate_header();
166 void invalidate();
167 int version() { return _header->_version; }
168 size_t alignment() { return _header->_alignment; }
169 size_t space_capacity(int i) { return _header->_space[i]._capacity; }
170 char* region_base(int i) { return _header->_space[i]._base; }
171 struct FileMapHeader* header() { return _header; }
172
173 static FileMapInfo* current_info() {
174 CDS_ONLY(return _current_info;)
175 NOT_CDS(return NULL;)
176 }
177
178 static void assert_mark(bool check);
179
180 // File manipulation.
181 bool initialize() NOT_CDS_RETURN_(false);
182 bool open_for_read();
183 void open_for_write();
184 void write_header();
185 void write_space(int i, Metaspace* space, bool read_only);
186 void write_region(int region, char* base, size_t size,
187 size_t capacity, bool read_only, bool allow_exec);
188 void write_bytes(const void* buffer, int count);
189 void write_bytes_aligned(const void* buffer, int count);
190 char* map_region(int i);
191 void unmap_region(int i);
192 bool verify_region_checksum(int i);
193 void close();
194 bool is_open() { return _file_open; }
195 ReservedSpace reserve_shared_memory();
196
197 // JVM/TI RedefineClasses() support:
198 // Remap the shared readonly space to shared readwrite, private.
199 bool remap_shared_readonly_as_readwrite();
200
201 // Errors.
202 static void fail_stop(const char *msg, ...) ATTRIBUTE_PRINTF(1, 2);
203 static void fail_continue(const char *msg, ...) ATTRIBUTE_PRINTF(1, 2);
204
205 // Return true if given address is in the mapped shared space.
206 bool is_in_shared_space(const void* p) NOT_CDS_RETURN_(false);
207 void print_shared_spaces() NOT_CDS_RETURN;
208
209 static size_t shared_spaces_size() {
210 return align_size_up(SharedReadOnlySize + SharedReadWriteSize +
211 SharedMiscDataSize + SharedMiscCodeSize,
212 os::vm_allocation_granularity());
213 }
214
215 // Stop CDS sharing and unmap CDS regions.
216 static void stop_sharing_and_unmap(const char* msg);
217
218 static void allocate_classpath_entry_table();
219 bool validate_classpath_entry_table();
220
221 static SharedClassPathEntry* shared_classpath(int index) {
222 char* p = (char*)_classpath_entry_table;
223 p += _classpath_entry_size * index;
224 return (SharedClassPathEntry*)p;
225 }
226 static const char* shared_classpath_name(int index) {
227 return shared_classpath(index)->_name;
228 }
229
230 static int get_number_of_share_classpaths() {
231 return _classpath_entry_table_size;
232 }
233 };
234
235 #endif // SHARE_VM_MEMORY_FILEMAP_HPP