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