1 /*
  2  * Copyright (c) 2003, 2021, 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_CDS_FILEMAP_HPP
 26 #define SHARE_CDS_FILEMAP_HPP
 27 
 28 #include "cds/metaspaceShared.hpp"
 29 #include "include/cds.h"
 30 #include "oops/array.hpp"
 31 #include "oops/compressedOops.hpp"
 32 #include "utilities/align.hpp"
 33 
 34 // To understand the layout of the CDS archive file:
 35 //
 36 // java -Xlog:cds+map=info:file=cds.map:none:filesize=0
 37 // java -Xlog:cds+map=debug:file=cds.map:none:filesize=0
 38 // java -Xlog:cds+map=trace:file=cds.map:none:filesize=0
 39 
 40 static const int JVM_IDENT_MAX = 256;
 41 
 42 class CHeapBitMap;
 43 class ClassFileStream;
 44 class ClassLoaderData;
 45 class ClassPathEntry;
 46 class outputStream;
 47 
 48 class SharedClassPathEntry {
 49   enum {
 50     modules_image_entry,
 51     jar_entry,
 52     dir_entry,
 53     non_existent_entry,
 54     unknown_entry
 55   };
 56 
 57   void set_name(const char* name, TRAPS);
 58 
 59   u1     _type;
 60   bool   _is_module_path;
 61   bool   _from_class_path_attr;
 62   time_t _timestamp;          // jar timestamp,  0 if is directory, modules image or other
 63   int64_t      _filesize;     // jar/jimage file size, -1 if is directory, -2 if other
 64   Array<char>* _name;
 65   Array<u1>*   _manifest;
 66 
 67 public:
 68   void init(bool is_modules_image, bool is_module_path, ClassPathEntry* cpe, TRAPS);
 69   void init_as_non_existent(const char* path, TRAPS);
 70   void metaspace_pointers_do(MetaspaceClosure* it);
 71   bool validate(bool is_class_path = true) const;
 72 
 73   // The _timestamp only gets set for jar files.
 74   bool has_timestamp() const {
 75     return _timestamp != 0;
 76   }
 77   bool is_dir()           const { return _type == dir_entry; }
 78   bool is_modules_image() const { return _type == modules_image_entry; }
 79   bool is_jar()           const { return _type == jar_entry; }
 80   bool from_class_path_attr() { return _from_class_path_attr; }
 81   time_t timestamp() const { return _timestamp; }
 82   const char* name() const;
 83   const char* manifest() const {
 84     return (_manifest == NULL) ? NULL : (const char*)_manifest->data();
 85   }
 86   int manifest_size() const {
 87     return (_manifest == NULL) ? 0 : _manifest->length();
 88   }
 89   void set_manifest(Array<u1>* manifest) {
 90     _manifest = manifest;
 91   }
 92   bool check_non_existent() const;
 93   void copy_from(SharedClassPathEntry* ent, ClassLoaderData* loader_data, TRAPS);
 94   bool in_named_module() {
 95     return is_modules_image() || // modules image doesn't contain unnamed modules
 96            _is_module_path;      // module path doesn't contain unnamed modules
 97   }
 98 };
 99 
100 struct ArchiveHeapOopmapInfo {
101   address _oopmap;               // bitmap for relocating embedded oops
102   size_t  _offset;               // this oopmap is stored at this offset from the bottom of the BM region
103   size_t  _oopmap_size_in_bits;
104   size_t  _oopmap_size_in_bytes;
105 };
106 
107 class SharedPathTable {
108   Array<u8>* _table;
109   int _size;
110 public:
111   SharedPathTable() : _table(NULL), _size(0) {}
112   SharedPathTable(Array<u8>* table, int size) : _table(table), _size(size) {}
113 
114   void dumptime_init(ClassLoaderData* loader_data, TRAPS);
115   void metaspace_pointers_do(MetaspaceClosure* it);
116 
117   int size() {
118     return _size;
119   }
120   SharedClassPathEntry* path_at(int index) {
121     if (index < 0) {
122       return NULL;
123     }
124     assert(index < _size, "sanity");
125     char* p = (char*)_table->data();
126     p += sizeof(SharedClassPathEntry) * index;
127     return (SharedClassPathEntry*)p;
128   }
129   Array<u8>* table() {return _table;}
130   void set_table(Array<u8>* table) {_table = table;}
131 };
132 
133 
134 class FileMapRegion: private CDSFileMapRegion {
135   void assert_is_heap_region() const {
136     assert(_is_heap_region, "must be heap region");
137   }
138   void assert_is_not_heap_region() const {
139     assert(!_is_heap_region, "must not be heap region");
140   }
141 
142 public:
143   static FileMapRegion* cast(CDSFileMapRegion* p) {
144     return (FileMapRegion*)p;
145   }
146 
147   // Accessors
148   int crc()                         const { return _crc; }
149   size_t file_offset()              const { return _file_offset; }
150   size_t mapping_offset()           const { return _mapping_offset; }
151   size_t mapping_end_offset()       const { return _mapping_offset + used_aligned(); }
152   size_t used()                     const { return _used; }
153   size_t used_aligned()             const; // aligned up to MetaspaceShared::core_region_alignment()
154   char*  mapped_base()              const { assert_is_not_heap_region(); return _mapped_base; }
155   char*  mapped_end()               const { return mapped_base()        + used_aligned(); }
156   bool   read_only()                const { return _read_only != 0; }
157   bool   allow_exec()               const { return _allow_exec != 0; }
158   bool   mapped_from_file()         const { return _mapped_from_file != 0; }
159   size_t oopmap_offset()            const { assert_is_heap_region();     return _oopmap_offset; }
160   size_t oopmap_size_in_bits()      const { assert_is_heap_region();     return _oopmap_size_in_bits; }
161 
162   void set_file_offset(size_t s)     { _file_offset = s; }
163   void set_read_only(bool v)         { _read_only = v; }
164   void set_mapped_base(char* p)      { _mapped_base = p; }
165   void set_mapped_from_file(bool v)  { _mapped_from_file = v; }
166   void init(int region_index, size_t mapping_offset, size_t size, bool read_only,
167             bool allow_exec, int crc);
168 
169   void init_oopmap(size_t oopmap_offset, size_t size_in_bits) {
170     _oopmap_offset = oopmap_offset;
171     _oopmap_size_in_bits = size_in_bits;
172   }
173 
174   void print(outputStream* st, int region_index);
175 };
176 
177 class FileMapHeader: private CDSFileMapHeaderBase {
178   friend class CDSOffsets;
179   friend class VMStructs;
180 
181   size_t _header_size;
182 
183   // The following fields record the states of the VM during dump time.
184   // They are compared with the runtime states to see if the archive
185   // can be used.
186   size_t _core_region_alignment;    // how shared archive should be aligned
187   int    _obj_alignment;            // value of ObjectAlignmentInBytes
188   address _narrow_oop_base;         // compressed oop encoding base
189   int    _narrow_oop_shift;         // compressed oop encoding shift
190   bool   _compact_strings;          // value of CompactStrings
191   bool   _compact_headers;          // value of UseCompactObjectHeaders
192   uintx  _max_heap_size;            // java max heap size during dumping
193   CompressedOops::Mode _narrow_oop_mode; // compressed oop encoding mode
194   int     _narrow_klass_shift;      // save narrow klass base and shift
195   bool    _compressed_oops;         // save the flag UseCompressedOops
196   bool    _compressed_class_ptrs;   // save the flag UseCompressedClassPointers
197   size_t  _cloned_vtables_offset;   // The address of the first cloned vtable
198   size_t  _serialized_data_offset;  // Data accessed using {ReadClosure,WriteClosure}::serialize()
199   address _heap_begin;              // heap begin at dump time.
200   address _heap_end;                // heap end at dump time.
201   bool _base_archive_is_default;    // indicates if the base archive is the system default one
202 
203   // The following fields are all sanity checks for whether this archive
204   // will function correctly with this JVM and the bootclasspath it's
205   // invoked with.
206   char  _jvm_ident[JVM_IDENT_MAX];  // identifier string of the jvm that created this dump
207 
208   // size of the base archive name including NULL terminator
209   size_t _base_archive_name_size;
210 
211   // The following is a table of all the boot/app/module path entries that were used
212   // during dumping. At run time, we validate these entries according to their
213   // SharedClassPathEntry::_type. See:
214   //      check_nonempty_dir_in_shared_path_table()
215   //      validate_shared_path_table()
216   //      validate_non_existent_class_paths()
217   size_t _shared_path_table_offset;
218   int    _shared_path_table_size;
219 
220   jshort _app_class_paths_start_index;  // Index of first app classpath entry
221   jshort _app_module_paths_start_index; // Index of first module path entry
222   jshort _num_module_paths;             // number of module path entries
223   jshort _max_used_path_index;          // max path index referenced during CDS dump
224   bool   _verify_local;                 // BytecodeVerificationLocal setting
225   bool   _verify_remote;                // BytecodeVerificationRemote setting
226   bool   _has_platform_or_app_classes;  // Archive contains app classes
227   char*  _requested_base_address;       // Archive relocation is not necessary if we map with this base address.
228   char*  _mapped_base_address;          // Actual base address where archive is mapped.
229 
230   bool   _allow_archiving_with_java_agent; // setting of the AllowArchivingWithJavaAgent option
231   bool   _use_optimized_module_handling;// No module-relation VM options were specified, so we can skip
232                                         // some expensive operations.
233   bool   _use_full_module_graph;        // Can we use the full archived module graph?
234   size_t _ptrmap_size_in_bits;          // Size of pointer relocation bitmap
235   narrowOop _heap_obj_roots;            // An objArray that stores all the roots of archived heap objects
236   char* from_mapped_offset(size_t offset) const {
237     return mapped_base_address() + offset;
238   }
239   void set_as_offset(char* p, size_t *offset);
240 public:
241   // Accessors -- fields declared in CDSFileMapHeaderBase
242   unsigned int magic()                    const { return _magic; }
243   int crc()                               const { return _crc; }
244   int version()                           const { return _version; }
245 
246   void set_crc(int crc_value)                   { _crc = crc_value; }
247   void set_version(int v)                       { _version = v; }
248 
249   // Accessors -- fields declared in FileMapHeader
250 
251   size_t header_size()                     const { return _header_size; }
252   size_t core_region_alignment()           const { return _core_region_alignment; }
253   int obj_alignment()                      const { return _obj_alignment; }
254   address narrow_oop_base()                const { return _narrow_oop_base; }
255   int narrow_oop_shift()                   const { return _narrow_oop_shift; }
256   bool compact_strings()                   const { return _compact_strings; }
257   bool compact_headers()                   const { return _compact_headers; }
258   uintx max_heap_size()                    const { return _max_heap_size; }
259   CompressedOops::Mode narrow_oop_mode()   const { return _narrow_oop_mode; }
260   int narrow_klass_shift()                 const { return _narrow_klass_shift; }
261   address narrow_klass_base()              const { return (address)mapped_base_address(); }
262   char* cloned_vtables()                   const { return from_mapped_offset(_cloned_vtables_offset); }
263   char* serialized_data()                  const { return from_mapped_offset(_serialized_data_offset); }
264   address heap_begin()                     const { return _heap_begin; }
265   address heap_end()                       const { return _heap_end; }
266   bool base_archive_is_default()           const { return _base_archive_is_default; }
267   const char* jvm_ident()                  const { return _jvm_ident; }
268   size_t base_archive_name_size()          const { return _base_archive_name_size; }
269   char* requested_base_address()           const { return _requested_base_address; }
270   char* mapped_base_address()              const { return _mapped_base_address; }
271   bool has_platform_or_app_classes()       const { return _has_platform_or_app_classes; }
272   size_t ptrmap_size_in_bits()             const { return _ptrmap_size_in_bits; }
273   bool compressed_oops()                   const { return _compressed_oops; }
274   bool compressed_class_pointers()         const { return _compressed_class_ptrs; }
275   // FIXME: These should really return int
276   jshort max_used_path_index()             const { return _max_used_path_index; }
277   jshort app_module_paths_start_index()    const { return _app_module_paths_start_index; }
278   jshort app_class_paths_start_index()     const { return _app_class_paths_start_index; }
279   jshort num_module_paths()                const { return _num_module_paths; }
280   narrowOop heap_obj_roots()               const { return _heap_obj_roots; }
281 
282   void set_has_platform_or_app_classes(bool v)   { _has_platform_or_app_classes = v; }
283   void set_cloned_vtables(char* p)               { set_as_offset(p, &_cloned_vtables_offset); }
284   void set_serialized_data(char* p)              { set_as_offset(p, &_serialized_data_offset); }
285   void set_base_archive_name_size(size_t s)      { _base_archive_name_size = s; }
286   void set_base_archive_is_default(bool b)       { _base_archive_is_default = b; }
287   void set_header_size(size_t s)                 { _header_size = s; }
288   void set_ptrmap_size_in_bits(size_t s)         { _ptrmap_size_in_bits = s; }
289   void set_mapped_base_address(char* p)          { _mapped_base_address = p; }
290   void set_heap_obj_roots(narrowOop r)           { _heap_obj_roots = r; }
291 
292   void set_shared_path_table(SharedPathTable table) {
293     set_as_offset((char*)table.table(), &_shared_path_table_offset);
294     _shared_path_table_size = table.size();
295   }
296 
297   void set_requested_base(char* b) {
298     _requested_base_address = b;
299     _mapped_base_address = 0;
300   }
301 
302   SharedPathTable shared_path_table() const {
303     return SharedPathTable((Array<u8>*)from_mapped_offset(_shared_path_table_offset),
304                            _shared_path_table_size);
305   }
306 
307   bool validate();
308   int compute_crc();
309 
310   FileMapRegion* space_at(int i) {
311     assert(is_valid_region(i), "invalid region");
312     return FileMapRegion::cast(&_space[i]);
313   }
314 
315   void populate(FileMapInfo* info, size_t core_region_alignment);
316 
317   static bool is_valid_region(int region) {
318     return (0 <= region && region < NUM_CDS_REGIONS);
319   }
320 
321   void print(outputStream* st);
322 };
323 
324 class FileMapInfo : public CHeapObj<mtInternal> {
325 private:
326   friend class ManifestStream;
327   friend class VMStructs;
328   friend class ArchiveBuilder;
329   friend class CDSOffsets;
330   friend class FileMapHeader;
331 
332   bool           _is_static;
333   bool           _file_open;
334   bool           _is_mapped;
335   int            _fd;
336   size_t         _file_offset;
337   const char*    _full_path;
338   const char*    _base_archive_name;
339   FileMapHeader* _header;
340 
341   // TODO: Probably change the following to be non-static
342   static SharedPathTable       _shared_path_table;
343   static SharedPathTable       _saved_shared_path_table;
344   static bool                  _validating_shared_path_table;
345 
346   // FileMapHeader describes the shared space data in the file to be
347   // mapped.  This structure gets written to a file.  It is not a class, so
348   // that the compilers don't add any compiler-private data to it.
349 
350   static FileMapInfo* _current_info;
351   static FileMapInfo* _dynamic_archive_info;
352   static bool _heap_pointers_need_patching;
353   static bool _memory_mapping_failed;
354   static GrowableArray<const char*>* _non_existent_class_paths;
355 
356   FileMapHeader *header() const       { return _header; }
357 
358 public:
359   static bool get_base_archive_name_from_header(const char* archive_name,
360                                                 int* size, char** base_archive_name);
361   static bool check_archive(const char* archive_name, bool is_static);
362   static SharedPathTable shared_path_table() {
363     return _shared_path_table;
364   }
365   static SharedPathTable saved_shared_path_table() {
366     return _saved_shared_path_table;
367   }
368 
369   bool init_from_file(int fd);
370   static void metaspace_pointers_do(MetaspaceClosure* it, bool use_copy = true);
371 
372   void log_paths(const char* msg, int start_idx, int end_idx);
373 
374   FileMapInfo(bool is_static);
375   ~FileMapInfo();
376 
377   // Accessors
378   int    compute_header_crc()  const { return header()->compute_crc(); }
379   void   set_header_crc(int crc)     { header()->set_crc(crc); }
380   int    space_crc(int i)      const { return space_at(i)->crc(); }
381   void   populate_header(size_t core_region_alignment);
382   bool   validate_header();
383   void   invalidate();
384   int    crc()                 const { return header()->crc(); }
385   int    version()             const { return header()->version(); }
386   unsigned int magic()         const { return header()->magic(); }
387   address narrow_oop_base()    const { return header()->narrow_oop_base(); }
388   int     narrow_oop_shift()   const { return header()->narrow_oop_shift(); }
389   uintx   max_heap_size()      const { return header()->max_heap_size(); }
390   address narrow_klass_base()  const { return header()->narrow_klass_base(); }
391   int     narrow_klass_shift() const { return header()->narrow_klass_shift(); }
392   size_t  core_region_alignment() const { return header()->core_region_alignment(); }
393 
394   void   set_header_base_archive_name_size(size_t size)      { header()->set_base_archive_name_size(size); }
395   void   set_header_base_archive_is_default(bool is_default) { header()->set_base_archive_is_default(is_default); }
396 
397   CompressedOops::Mode narrow_oop_mode()      const { return header()->narrow_oop_mode(); }
398   jshort app_module_paths_start_index()       const { return header()->app_module_paths_start_index(); }
399   jshort app_class_paths_start_index()        const { return header()->app_class_paths_start_index(); }
400 
401   char* cloned_vtables()                      const { return header()->cloned_vtables(); }
402   void  set_cloned_vtables(char* p)           const { header()->set_cloned_vtables(p); }
403   char* serialized_data()                     const { return header()->serialized_data(); }
404   void  set_serialized_data(char* p)          const { header()->set_serialized_data(p); }
405 
406   bool  is_file_position_aligned() const;
407   void  align_file_position();
408 
409   bool is_static()                            const { return _is_static; }
410   bool is_mapped()                            const { return _is_mapped; }
411   void set_is_mapped(bool v)                        { _is_mapped = v; }
412   const char* full_path()                     const { return _full_path; }
413 
414   void set_requested_base(char* b)                  { header()->set_requested_base(b); }
415   char* requested_base_address()           const    { return header()->requested_base_address(); }
416 
417   class DynamicArchiveHeader* dynamic_header() const {
418     assert(!is_static(), "must be");
419     return (DynamicArchiveHeader*)header();
420   }
421 
422   void set_has_platform_or_app_classes(bool v) {
423     header()->set_has_platform_or_app_classes(v);
424   }
425   bool has_platform_or_app_classes() const {
426     return header()->has_platform_or_app_classes();
427   }
428 
429   static FileMapInfo* current_info() {
430     CDS_ONLY(return _current_info;)
431     NOT_CDS(return NULL;)
432   }
433 
434   static void set_current_info(FileMapInfo* info) {
435     CDS_ONLY(_current_info = info;)
436   }
437 
438   static FileMapInfo* dynamic_info() {
439     CDS_ONLY(return _dynamic_archive_info;)
440     NOT_CDS(return NULL;)
441   }
442 
443   static void assert_mark(bool check);
444 
445   // File manipulation.
446   bool  initialize() NOT_CDS_RETURN_(false);
447   bool  open_for_read();
448   void  open_for_write(const char* path = NULL);
449   void  write_header();
450   void  write_region(int region, char* base, size_t size,
451                      bool read_only, bool allow_exec);
452   char* write_bitmap_region(const CHeapBitMap* ptrmap,
453                             GrowableArray<ArchiveHeapOopmapInfo>* closed_oopmaps,
454                             GrowableArray<ArchiveHeapOopmapInfo>* open_oopmaps,
455                             size_t &size_in_bytes);
456   size_t write_archive_heap_regions(GrowableArray<MemRegion> *heap_mem,
457                                     GrowableArray<ArchiveHeapOopmapInfo> *oopmaps,
458                                     int first_region_id, int max_num_regions);
459   void  write_bytes(const void* buffer, size_t count);
460   void  write_bytes_aligned(const void* buffer, size_t count);
461   size_t  read_bytes(void* buffer, size_t count);
462   MapArchiveResult map_regions(int regions[], int num_regions, char* mapped_base_address, ReservedSpace rs);
463   void  unmap_regions(int regions[], int num_regions);
464   void  map_heap_regions() NOT_CDS_JAVA_HEAP_RETURN;
465   void  fixup_mapped_heap_regions() NOT_CDS_JAVA_HEAP_RETURN;
466   void  patch_archived_heap_embedded_pointers() NOT_CDS_JAVA_HEAP_RETURN;
467   void  patch_archived_heap_embedded_pointers(MemRegion* ranges, int num_ranges,
468                                               int first_region_idx) NOT_CDS_JAVA_HEAP_RETURN;
469   bool  has_heap_regions()  NOT_CDS_JAVA_HEAP_RETURN_(false);
470   MemRegion get_heap_regions_range_with_current_oop_encoding_mode() NOT_CDS_JAVA_HEAP_RETURN_(MemRegion());
471   void  unmap_region(int i);
472   bool  verify_region_checksum(int i);
473   void  close();
474   bool  is_open() { return _file_open; }
475   ReservedSpace reserve_shared_memory();
476 
477   // JVM/TI RedefineClasses() support:
478   // Remap the shared readonly space to shared readwrite, private.
479   bool  remap_shared_readonly_as_readwrite();
480 
481   // Errors.
482   static void fail_stop(const char *msg, ...) ATTRIBUTE_PRINTF(1, 2);
483   static void fail_continue(const char *msg, ...) ATTRIBUTE_PRINTF(1, 2);
484   static bool memory_mapping_failed() {
485     CDS_ONLY(return _memory_mapping_failed;)
486     NOT_CDS(return false;)
487   }
488   bool is_in_shared_region(const void* p, int idx) NOT_CDS_RETURN_(false);
489 
490   // Stop CDS sharing and unmap CDS regions.
491   static void stop_sharing_and_unmap(const char* msg);
492 
493   static void allocate_shared_path_table(TRAPS);
494   static void copy_shared_path_table(ClassLoaderData* loader_data, TRAPS);
495   static int add_shared_classpaths(int i, const char* which, ClassPathEntry *cpe, TRAPS);
496   static void check_nonempty_dir_in_shared_path_table();
497   bool validate_shared_path_table();
498   void validate_non_existent_class_paths();
499   static void set_shared_path_table(FileMapInfo* info) {
500     _shared_path_table = info->header()->shared_path_table();
501   }
502   static void update_jar_manifest(ClassPathEntry *cpe, SharedClassPathEntry* ent, TRAPS);
503   static int num_non_existent_class_paths();
504   static void record_non_existent_class_path_entry(const char* path);
505 
506 #if INCLUDE_JVMTI
507   static ClassFileStream* open_stream_for_jvmti(InstanceKlass* ik, Handle class_loader, TRAPS);
508 #endif
509 
510   static SharedClassPathEntry* shared_path(int index) {
511     return _shared_path_table.path_at(index);
512   }
513 
514   static const char* shared_path_name(int index) {
515     assert(index >= 0, "Sanity");
516     return shared_path(index)->name();
517   }
518 
519   static int get_number_of_shared_paths() {
520     return _shared_path_table.size();
521   }
522 
523   static int get_module_shared_path_index(Symbol* location) NOT_CDS_RETURN_(-1);
524 
525   char* region_addr(int idx);
526 
527   // The offset of the first core region in the archive, relative to SharedBaseAddress
528   size_t mapping_base_offset() const { return first_core_space()->mapping_offset(); }
529   // The offset of the (exclusive) end of the last core region in this archive, relative to SharedBaseAddress
530   size_t mapping_end_offset()  const { return last_core_space()->mapping_end_offset(); }
531 
532   char* mapped_base()    const { return first_core_space()->mapped_base(); }
533   char* mapped_end()     const { return last_core_space()->mapped_end();   }
534 
535   // Non-zero if the archive needs to be mapped a non-default location due to ASLR.
536   intx relocation_delta() const {
537     return header()->mapped_base_address() - header()->requested_base_address();
538   }
539 
540   FileMapRegion* first_core_space() const;
541   FileMapRegion* last_core_space() const;
542 
543   FileMapRegion* space_at(int i) const {
544     return header()->space_at(i);
545   }
546 
547   void print(outputStream* st) {
548     header()->print(st);
549   }
550 
551   const char* vm_version() {
552     return header()->jvm_ident();
553   }
554 
555  private:
556   void  seek_to_position(size_t pos);
557   char* skip_first_path_entry(const char* path) NOT_CDS_RETURN_(NULL);
558   int   num_paths(const char* path) NOT_CDS_RETURN_(0);
559   GrowableArray<const char*>* create_path_array(const char* path) NOT_CDS_RETURN_(NULL);
560   bool  classpath_failure(const char* msg, const char* name) NOT_CDS_RETURN_(false);
561   bool  check_paths(int shared_path_start_idx, int num_paths,
562                     GrowableArray<const char*>* rp_array) NOT_CDS_RETURN_(false);
563   bool  validate_boot_class_paths() NOT_CDS_RETURN_(false);
564   bool  validate_app_class_paths(int shared_app_paths_len) NOT_CDS_RETURN_(false);
565   bool  map_heap_data(MemRegion **heap_mem, int first, int max, int* num,
566                       bool is_open = false) NOT_CDS_JAVA_HEAP_RETURN_(false);
567   bool  region_crc_check(char* buf, size_t size, int expected_crc) NOT_CDS_RETURN_(false);
568   void  dealloc_archive_heap_regions(MemRegion* regions, int num) NOT_CDS_JAVA_HEAP_RETURN;
569   void  map_heap_regions_impl() NOT_CDS_JAVA_HEAP_RETURN;
570   char* map_bitmap_region();
571   MapArchiveResult map_region(int i, intx addr_delta, char* mapped_base_address, ReservedSpace rs);
572   bool  read_region(int i, char* base, size_t size);
573   bool  relocate_pointers_in_core_regions(intx addr_delta);
574   static size_t set_oopmaps_offset(GrowableArray<ArchiveHeapOopmapInfo> *oopmaps, size_t curr_size);
575   static size_t write_oopmaps(GrowableArray<ArchiveHeapOopmapInfo> *oopmaps, size_t curr_offset, char* buffer);
576 
577   // The starting address of spc, as calculated with CompressedOop::decode_non_null()
578   address start_address_as_decoded_with_current_oop_encoding_mode(FileMapRegion* spc) {
579     return decode_start_address(spc, true);
580   }
581 
582   // The starting address of spc, as calculated with HeapShared::decode_from_archive()
583   address start_address_as_decoded_from_archive(FileMapRegion* spc) {
584     return decode_start_address(spc, false);
585   }
586 
587   address decode_start_address(FileMapRegion* spc, bool with_current_oop_encoding_mode);
588 
589 #if INCLUDE_JVMTI
590   static ClassPathEntry** _classpath_entries_for_jvmti;
591   static ClassPathEntry* get_classpath_entry_for_jvmti(int i, TRAPS);
592 #endif
593 };
594 
595 #endif // SHARE_CDS_FILEMAP_HPP