1 /*
   2  * Copyright (c) 2003, 2025, 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 #include "cds/aotClassLocation.hpp"
  26 #include "cds/archiveBuilder.hpp"
  27 #include "cds/archiveHeapLoader.inline.hpp"
  28 #include "cds/archiveHeapWriter.hpp"
  29 #include "cds/archiveUtils.inline.hpp"
  30 #include "cds/cds_globals.hpp"
  31 #include "cds/cdsConfig.hpp"
  32 #include "cds/dynamicArchive.hpp"
  33 #include "cds/filemap.hpp"
  34 #include "cds/heapShared.hpp"
  35 #include "cds/metaspaceShared.hpp"
  36 #include "classfile/altHashing.hpp"
  37 #include "classfile/classFileStream.hpp"
  38 #include "classfile/classLoader.hpp"
  39 #include "classfile/classLoader.inline.hpp"
  40 #include "classfile/classLoaderData.inline.hpp"
  41 #include "classfile/classLoaderExt.hpp"
  42 #include "classfile/symbolTable.hpp"
  43 #include "classfile/systemDictionaryShared.hpp"
  44 #include "classfile/vmClasses.hpp"
  45 #include "classfile/vmSymbols.hpp"
  46 #include "jvm.h"
  47 #include "logging/log.hpp"
  48 #include "logging/logMessage.hpp"
  49 #include "logging/logStream.hpp"
  50 #include "memory/iterator.inline.hpp"
  51 #include "memory/metadataFactory.hpp"
  52 #include "memory/metaspaceClosure.hpp"
  53 #include "memory/oopFactory.hpp"
  54 #include "memory/universe.hpp"
  55 #include "nmt/memTracker.hpp"
  56 #include "oops/access.hpp"
  57 #include "oops/compressedOops.hpp"
  58 #include "oops/compressedOops.inline.hpp"
  59 #include "oops/compressedKlass.hpp"
  60 #include "oops/objArrayOop.hpp"
  61 #include "oops/oop.inline.hpp"
  62 #include "oops/typeArrayKlass.hpp"
  63 #include "prims/jvmtiExport.hpp"
  64 #include "runtime/arguments.hpp"
  65 #include "runtime/globals_extension.hpp"
  66 #include "runtime/java.hpp"
  67 #include "runtime/javaCalls.hpp"
  68 #include "runtime/mutexLocker.hpp"
  69 #include "runtime/os.hpp"
  70 #include "runtime/vm_version.hpp"
  71 #include "utilities/align.hpp"
  72 #include "utilities/bitMap.inline.hpp"
  73 #include "utilities/classpathStream.hpp"
  74 #include "utilities/defaultStream.hpp"
  75 #include "utilities/ostream.hpp"
  76 #if INCLUDE_G1GC
  77 #include "gc/g1/g1CollectedHeap.hpp"
  78 #include "gc/g1/g1HeapRegion.hpp"
  79 #endif
  80 
  81 # include <sys/stat.h>
  82 # include <errno.h>
  83 
  84 #ifndef O_BINARY       // if defined (Win32) use binary files.
  85 #define O_BINARY 0     // otherwise do nothing.
  86 #endif
  87 
  88 // Fill in the fileMapInfo structure with data about this VM instance.
  89 
  90 // This method copies the vm version info into header_version.  If the version is too
  91 // long then a truncated version, which has a hash code appended to it, is copied.
  92 //
  93 // Using a template enables this method to verify that header_version is an array of
  94 // length JVM_IDENT_MAX.  This ensures that the code that writes to the CDS file and
  95 // the code that reads the CDS file will both use the same size buffer.  Hence, will
  96 // use identical truncation.  This is necessary for matching of truncated versions.
  97 template <int N> static void get_header_version(char (&header_version) [N]) {
  98   assert(N == JVM_IDENT_MAX, "Bad header_version size");
  99 
 100   const char *vm_version = VM_Version::internal_vm_info_string();
 101   const int version_len = (int)strlen(vm_version);
 102 
 103   memset(header_version, 0, JVM_IDENT_MAX);
 104 
 105   if (version_len < (JVM_IDENT_MAX-1)) {
 106     strcpy(header_version, vm_version);
 107 
 108   } else {
 109     // Get the hash value.  Use a static seed because the hash needs to return the same
 110     // value over multiple jvm invocations.
 111     uint32_t hash = AltHashing::halfsiphash_32(8191, (const uint8_t*)vm_version, version_len);
 112 
 113     // Truncate the ident, saving room for the 8 hex character hash value.
 114     strncpy(header_version, vm_version, JVM_IDENT_MAX-9);
 115 
 116     // Append the hash code as eight hex digits.
 117     os::snprintf_checked(&header_version[JVM_IDENT_MAX-9], 9, "%08x", hash);
 118     header_version[JVM_IDENT_MAX-1] = 0;  // Null terminate.
 119   }
 120 
 121   assert(header_version[JVM_IDENT_MAX-1] == 0, "must be");
 122 }
 123 
 124 FileMapInfo::FileMapInfo(const char* full_path, bool is_static) :
 125   _is_static(is_static), _file_open(false), _is_mapped(false), _fd(-1), _file_offset(0),
 126   _full_path(full_path), _base_archive_name(nullptr), _header(nullptr) {
 127   if (_is_static) {
 128     assert(_current_info == nullptr, "must be singleton"); // not thread safe
 129     _current_info = this;
 130   } else {
 131     assert(_dynamic_archive_info == nullptr, "must be singleton"); // not thread safe
 132     _dynamic_archive_info = this;
 133   }
 134 }
 135 
 136 FileMapInfo::~FileMapInfo() {
 137   if (_is_static) {
 138     assert(_current_info == this, "must be singleton"); // not thread safe
 139     _current_info = nullptr;
 140   } else {
 141     assert(_dynamic_archive_info == this, "must be singleton"); // not thread safe
 142     _dynamic_archive_info = nullptr;
 143   }
 144 
 145   if (_header != nullptr) {
 146     os::free(_header);
 147   }
 148 
 149   if (_file_open) {
 150     ::close(_fd);
 151   }
 152 }
 153 
 154 void FileMapInfo::free_current_info() {
 155   assert(CDSConfig::is_dumping_final_static_archive(), "only supported in this mode");
 156   assert(_current_info != nullptr, "sanity");
 157   delete _current_info;
 158   assert(_current_info == nullptr, "sanity"); // Side effect expected from the above "delete" operator.
 159 }
 160 
 161 void FileMapInfo::populate_header(size_t core_region_alignment) {
 162   assert(_header == nullptr, "Sanity check");
 163   size_t c_header_size;
 164   size_t header_size;
 165   size_t base_archive_name_size = 0;
 166   size_t base_archive_name_offset = 0;
 167   if (is_static()) {
 168     c_header_size = sizeof(FileMapHeader);
 169     header_size = c_header_size;
 170   } else {
 171     // dynamic header including base archive name for non-default base archive
 172     c_header_size = sizeof(DynamicArchiveHeader);
 173     header_size = c_header_size;
 174 
 175     const char* default_base_archive_name = CDSConfig::default_archive_path();
 176     const char* current_base_archive_name = CDSConfig::static_archive_path();
 177     if (!os::same_files(current_base_archive_name, default_base_archive_name)) {
 178       base_archive_name_size = strlen(current_base_archive_name) + 1;
 179       header_size += base_archive_name_size;
 180       base_archive_name_offset = c_header_size;
 181     }
 182   }
 183   _header = (FileMapHeader*)os::malloc(header_size, mtInternal);
 184   memset((void*)_header, 0, header_size);
 185   _header->populate(this,
 186                     core_region_alignment,
 187                     header_size,
 188                     base_archive_name_size,
 189                     base_archive_name_offset);
 190 }
 191 
 192 void FileMapHeader::populate(FileMapInfo *info, size_t core_region_alignment,
 193                              size_t header_size, size_t base_archive_name_size,
 194                              size_t base_archive_name_offset) {
 195   // 1. We require _generic_header._magic to be at the beginning of the file
 196   // 2. FileMapHeader also assumes that _generic_header is at the beginning of the file
 197   assert(offset_of(FileMapHeader, _generic_header) == 0, "must be");
 198   set_header_size((unsigned int)header_size);
 199   set_base_archive_name_offset((unsigned int)base_archive_name_offset);
 200   set_base_archive_name_size((unsigned int)base_archive_name_size);
 201   if (CDSConfig::is_dumping_dynamic_archive()) {
 202     set_magic(CDS_DYNAMIC_ARCHIVE_MAGIC);
 203   } else if (CDSConfig::is_dumping_preimage_static_archive()) {
 204     set_magic(CDS_PREIMAGE_ARCHIVE_MAGIC);
 205   } else {
 206     set_magic(CDS_ARCHIVE_MAGIC);
 207   }
 208   set_version(CURRENT_CDS_ARCHIVE_VERSION);
 209 
 210   if (!info->is_static() && base_archive_name_size != 0) {
 211     // copy base archive name
 212     copy_base_archive_name(CDSConfig::static_archive_path());
 213   }
 214   _core_region_alignment = core_region_alignment;
 215   _obj_alignment = ObjectAlignmentInBytes;
 216   _compact_strings = CompactStrings;
 217   _compact_headers = UseCompactObjectHeaders;
 218   if (CDSConfig::is_dumping_heap()) {
 219     _narrow_oop_mode = CompressedOops::mode();
 220     _narrow_oop_base = CompressedOops::base();
 221     _narrow_oop_shift = CompressedOops::shift();
 222   }
 223   _compressed_oops = UseCompressedOops;
 224   _compressed_class_ptrs = UseCompressedClassPointers;
 225   if (UseCompressedClassPointers) {
 226 #ifdef _LP64
 227     _narrow_klass_pointer_bits = CompressedKlassPointers::narrow_klass_pointer_bits();
 228     _narrow_klass_shift = ArchiveBuilder::precomputed_narrow_klass_shift();
 229 #endif
 230   } else {
 231     _narrow_klass_pointer_bits = _narrow_klass_shift = -1;
 232   }
 233   _max_heap_size = MaxHeapSize;
 234   _use_optimized_module_handling = CDSConfig::is_using_optimized_module_handling();
 235   _has_aot_linked_classes = CDSConfig::is_dumping_aot_linked_classes();
 236   _has_full_module_graph = CDSConfig::is_dumping_full_module_graph();
 237   _has_archived_packages = CDSConfig::is_dumping_packages();
 238   _has_archived_protection_domains = CDSConfig::is_dumping_protection_domains();
 239   _gc_kind = (int)Universe::heap()->kind();
 240   jio_snprintf(_gc_name, sizeof(_gc_name), Universe::heap()->name());
 241 
 242   // The following fields are for sanity checks for whether this archive
 243   // will function correctly with this JVM and the bootclasspath it's
 244   // invoked with.
 245 
 246   // JVM version string ... changes on each build.
 247   get_header_version(_jvm_ident);
 248 
 249   _verify_local = BytecodeVerificationLocal;
 250   _verify_remote = BytecodeVerificationRemote;
 251   _has_platform_or_app_classes = AOTClassLocationConfig::dumptime()->has_platform_or_app_classes();
 252   _requested_base_address = (char*)SharedBaseAddress;
 253   _mapped_base_address = (char*)SharedBaseAddress;
 254   _allow_archiving_with_java_agent = AllowArchivingWithJavaAgent;
 255 }
 256 
 257 void FileMapHeader::copy_base_archive_name(const char* archive) {
 258   assert(base_archive_name_size() != 0, "_base_archive_name_size not set");
 259   assert(base_archive_name_offset() != 0, "_base_archive_name_offset not set");
 260   assert(header_size() > sizeof(*this), "_base_archive_name_size not included in header size?");
 261   memcpy((char*)this + base_archive_name_offset(), archive, base_archive_name_size());
 262 }
 263 
 264 void FileMapHeader::print(outputStream* st) {
 265   ResourceMark rm;
 266 
 267   st->print_cr("- magic:                          0x%08x", magic());
 268   st->print_cr("- crc:                            0x%08x", crc());
 269   st->print_cr("- version:                        0x%x", version());
 270   st->print_cr("- header_size:                    " UINT32_FORMAT, header_size());
 271   st->print_cr("- base_archive_name_offset:       " UINT32_FORMAT, base_archive_name_offset());
 272   st->print_cr("- base_archive_name_size:         " UINT32_FORMAT, base_archive_name_size());
 273 
 274   for (int i = 0; i < NUM_CDS_REGIONS; i++) {
 275     FileMapRegion* r = region_at(i);
 276     r->print(st, i);
 277   }
 278   st->print_cr("============ end regions ======== ");
 279 
 280   st->print_cr("- core_region_alignment:          %zu", _core_region_alignment);
 281   st->print_cr("- obj_alignment:                  %d", _obj_alignment);
 282   st->print_cr("- narrow_oop_base:                " INTPTR_FORMAT, p2i(_narrow_oop_base));
 283   st->print_cr("- narrow_oop_shift                %d", _narrow_oop_shift);
 284   st->print_cr("- compact_strings:                %d", _compact_strings);
 285   st->print_cr("- compact_headers:                %d", _compact_headers);
 286   st->print_cr("- max_heap_size:                  %zu", _max_heap_size);
 287   st->print_cr("- narrow_oop_mode:                %d", _narrow_oop_mode);
 288   st->print_cr("- compressed_oops:                %d", _compressed_oops);
 289   st->print_cr("- compressed_class_ptrs:          %d", _compressed_class_ptrs);
 290   st->print_cr("- narrow_klass_pointer_bits:      %d", _narrow_klass_pointer_bits);
 291   st->print_cr("- narrow_klass_shift:             %d", _narrow_klass_shift);
 292   st->print_cr("- cloned_vtables_offset:          0x%zx", _cloned_vtables_offset);
 293   st->print_cr("- early_serialized_data_offset:   0x%zx", _early_serialized_data_offset);
 294   st->print_cr("- serialized_data_offset:         0x%zx", _serialized_data_offset);
 295   st->print_cr("- jvm_ident:                      %s", _jvm_ident);
 296   st->print_cr("- class_location_config_offset:   0x%zx", _class_location_config_offset);
 297   st->print_cr("- verify_local:                   %d", _verify_local);
 298   st->print_cr("- verify_remote:                  %d", _verify_remote);
 299   st->print_cr("- has_platform_or_app_classes:    %d", _has_platform_or_app_classes);
 300   st->print_cr("- requested_base_address:         " INTPTR_FORMAT, p2i(_requested_base_address));
 301   st->print_cr("- mapped_base_address:            " INTPTR_FORMAT, p2i(_mapped_base_address));
 302   st->print_cr("- heap_root_segments.roots_count: %d" , _heap_root_segments.roots_count());
 303   st->print_cr("- heap_root_segments.base_offset: 0x%zx", _heap_root_segments.base_offset());
 304   st->print_cr("- heap_root_segments.count:       %zu", _heap_root_segments.count());
 305   st->print_cr("- heap_root_segments.max_size_elems: %d", _heap_root_segments.max_size_in_elems());
 306   st->print_cr("- heap_root_segments.max_size_bytes: %d", _heap_root_segments.max_size_in_bytes());
 307   st->print_cr("- _heap_oopmap_start_pos:         %zu", _heap_oopmap_start_pos);
 308   st->print_cr("- _heap_ptrmap_start_pos:         %zu", _heap_ptrmap_start_pos);
 309   st->print_cr("- _rw_ptrmap_start_pos:           %zu", _rw_ptrmap_start_pos);
 310   st->print_cr("- _ro_ptrmap_start_pos:           %zu", _ro_ptrmap_start_pos);
 311   st->print_cr("- allow_archiving_with_java_agent:%d", _allow_archiving_with_java_agent);
 312   st->print_cr("- use_optimized_module_handling:  %d", _use_optimized_module_handling);
 313   st->print_cr("- has_full_module_graph           %d", _has_full_module_graph);
 314   st->print_cr("- has_aot_linked_classes          %d", _has_aot_linked_classes);
 315   st->print_cr("- has_archived_packages           %d", _has_archived_packages);
 316   st->print_cr("- has_archived_protection_domains %d", _has_archived_protection_domains);
 317   st->print_cr("- ptrmap_size_in_bits:            %zu", _ptrmap_size_in_bits);
 318 }
 319 
 320 bool FileMapInfo::validate_class_location() {
 321   assert(CDSConfig::is_using_archive(), "runtime only");
 322 
 323   AOTClassLocationConfig* config = header()->class_location_config();
 324   bool has_extra_module_paths = false;
 325   if (!config->validate(header()->has_aot_linked_classes(), &has_extra_module_paths)) {
 326     if (PrintSharedArchiveAndExit) {
 327       MetaspaceShared::set_archive_loading_failed();
 328       return true;
 329     } else {
 330       return false;
 331     }
 332   }
 333 
 334   if (header()->has_full_module_graph() && has_extra_module_paths) {
 335     CDSConfig::stop_using_optimized_module_handling();
 336     log_info(cds)("optimized module handling: disabled because extra module path(s) are specified");
 337   }
 338 
 339   if (CDSConfig::is_dumping_dynamic_archive()) {
 340     // Only support dynamic dumping with the usage of the default CDS archive
 341     // or a simple base archive.
 342     // If the base layer archive contains additional path component besides
 343     // the runtime image and the -cp, dynamic dumping is disabled.
 344     if (config->num_boot_classpaths() > 0) {
 345       CDSConfig::disable_dumping_dynamic_archive();
 346       log_warning(cds)(
 347         "Dynamic archiving is disabled because base layer archive has appended boot classpath");
 348     }
 349     if (config->num_module_paths() > 0) {
 350       if (has_extra_module_paths) {
 351         CDSConfig::disable_dumping_dynamic_archive();
 352         log_warning(cds)(
 353           "Dynamic archiving is disabled because base layer archive has a different module path");
 354       }
 355     }
 356   }
 357 
 358 #if INCLUDE_JVMTI
 359   if (_classpath_entries_for_jvmti != nullptr) {
 360     os::free(_classpath_entries_for_jvmti);
 361   }
 362   size_t sz = sizeof(ClassPathEntry*) * AOTClassLocationConfig::runtime()->length();
 363   _classpath_entries_for_jvmti = (ClassPathEntry**)os::malloc(sz, mtClass);
 364   memset((void*)_classpath_entries_for_jvmti, 0, sz);
 365 #endif
 366 
 367   return true;
 368 }
 369 
 370 // A utility class for reading/validating the GenericCDSFileMapHeader portion of
 371 // a CDS archive's header. The file header of all CDS archives with versions from
 372 // CDS_GENERIC_HEADER_SUPPORTED_MIN_VERSION (12) are guaranteed to always start
 373 // with GenericCDSFileMapHeader. This makes it possible to read important information
 374 // from a CDS archive created by a different version of HotSpot, so that we can
 375 // automatically regenerate the archive as necessary (JDK-8261455).
 376 class FileHeaderHelper {
 377   int _fd;
 378   bool _is_valid;
 379   bool _is_static;
 380   GenericCDSFileMapHeader* _header;
 381   const char* _archive_name;
 382   const char* _base_archive_name;
 383 
 384 public:
 385   FileHeaderHelper(const char* archive_name, bool is_static) {
 386     _fd = -1;
 387     _is_valid = false;
 388     _header = nullptr;
 389     _base_archive_name = nullptr;
 390     _archive_name = archive_name;
 391     _is_static = is_static;
 392   }
 393 
 394   ~FileHeaderHelper() {
 395     if (_header != nullptr) {
 396       FREE_C_HEAP_ARRAY(char, _header);
 397     }
 398     if (_fd != -1) {
 399       ::close(_fd);
 400     }
 401   }
 402 
 403   bool initialize() {
 404     assert(_archive_name != nullptr, "Archive name is null");
 405     _fd = os::open(_archive_name, O_RDONLY | O_BINARY, 0);
 406     if (_fd < 0) {
 407       log_info(cds)("Specified %s not found (%s)", CDSConfig::type_of_archive_being_loaded(), _archive_name);
 408       return false;
 409     }
 410     return initialize(_fd);
 411   }
 412 
 413   // for an already opened file, do not set _fd
 414   bool initialize(int fd) {
 415     assert(_archive_name != nullptr, "Archive name is null");
 416     assert(fd != -1, "Archive must be opened already");
 417     // First read the generic header so we know the exact size of the actual header.
 418     const char* file_type = CDSConfig::type_of_archive_being_loaded();
 419     GenericCDSFileMapHeader gen_header;
 420     size_t size = sizeof(GenericCDSFileMapHeader);
 421     os::lseek(fd, 0, SEEK_SET);
 422     size_t n = ::read(fd, (void*)&gen_header, (unsigned int)size);
 423     if (n != size) {
 424       log_warning(cds)("Unable to read generic CDS file map header from %s", file_type);
 425       return false;
 426     }
 427 
 428     if (gen_header._magic != CDS_ARCHIVE_MAGIC &&
 429         gen_header._magic != CDS_DYNAMIC_ARCHIVE_MAGIC &&
 430         gen_header._magic != CDS_PREIMAGE_ARCHIVE_MAGIC) {
 431       log_warning(cds)("The %s has a bad magic number: %#x", file_type, gen_header._magic);
 432       return false;
 433     }
 434 
 435     if (gen_header._version < CDS_GENERIC_HEADER_SUPPORTED_MIN_VERSION) {
 436       log_warning(cds)("Cannot handle %s version 0x%x. Must be at least 0x%x.",
 437                        file_type, gen_header._version, CDS_GENERIC_HEADER_SUPPORTED_MIN_VERSION);
 438       return false;
 439     }
 440 
 441     if (gen_header._version !=  CURRENT_CDS_ARCHIVE_VERSION) {
 442       log_warning(cds)("The %s version 0x%x does not match the required version 0x%x.",
 443                        file_type, gen_header._version, CURRENT_CDS_ARCHIVE_VERSION);
 444     }
 445 
 446     size_t filelen = os::lseek(fd, 0, SEEK_END);
 447     if (gen_header._header_size >= filelen) {
 448       log_warning(cds)("Archive file header larger than archive file");
 449       return false;
 450     }
 451 
 452     // Read the actual header and perform more checks
 453     size = gen_header._header_size;
 454     _header = (GenericCDSFileMapHeader*)NEW_C_HEAP_ARRAY(char, size, mtInternal);
 455     os::lseek(fd, 0, SEEK_SET);
 456     n = ::read(fd, (void*)_header, (unsigned int)size);
 457     if (n != size) {
 458       log_warning(cds)("Unable to read file map header from %s", file_type);
 459       return false;
 460     }
 461 
 462     if (!check_header_crc()) {
 463       return false;
 464     }
 465 
 466     if (!check_and_init_base_archive_name()) {
 467       return false;
 468     }
 469 
 470     // All fields in the GenericCDSFileMapHeader has been validated.
 471     _is_valid = true;
 472     return true;
 473   }
 474 
 475   GenericCDSFileMapHeader* get_generic_file_header() {
 476     assert(_header != nullptr && _is_valid, "must be a valid archive file");
 477     return _header;
 478   }
 479 
 480   const char* base_archive_name() {
 481     assert(_header != nullptr && _is_valid, "must be a valid archive file");
 482     return _base_archive_name;
 483   }
 484 
 485   bool is_static_archive() const {
 486     return _header->_magic == CDS_ARCHIVE_MAGIC;
 487   }
 488 
 489   bool is_dynamic_archive() const {
 490     return _header->_magic == CDS_DYNAMIC_ARCHIVE_MAGIC;
 491   }
 492 
 493   bool is_preimage_static_archive() const {
 494     return _header->_magic == CDS_PREIMAGE_ARCHIVE_MAGIC;
 495   }
 496 
 497  private:
 498   bool check_header_crc() const {
 499     if (VerifySharedSpaces) {
 500       FileMapHeader* header = (FileMapHeader*)_header;
 501       int actual_crc = header->compute_crc();
 502       if (actual_crc != header->crc()) {
 503         log_info(cds)("_crc expected: %d", header->crc());
 504         log_info(cds)("       actual: %d", actual_crc);
 505         log_warning(cds)("Header checksum verification failed.");
 506         return false;
 507       }
 508     }
 509     return true;
 510   }
 511 
 512   bool check_and_init_base_archive_name() {
 513     unsigned int name_offset = _header->_base_archive_name_offset;
 514     unsigned int name_size   = _header->_base_archive_name_size;
 515     unsigned int header_size = _header->_header_size;
 516 
 517     if (name_offset + name_size < name_offset) {
 518       log_warning(cds)("base_archive_name offset/size overflow: " UINT32_FORMAT "/" UINT32_FORMAT,
 519                                  name_offset, name_size);
 520       return false;
 521     }
 522 
 523     if (is_static_archive() || is_preimage_static_archive()) {
 524       if (name_offset != 0) {
 525         log_warning(cds)("static shared archive must have zero _base_archive_name_offset");
 526         return false;
 527       }
 528       if (name_size != 0) {
 529         log_warning(cds)("static shared archive must have zero _base_archive_name_size");
 530         return false;
 531       }
 532     } else {
 533       assert(is_dynamic_archive(), "must be");
 534       if ((name_size == 0 && name_offset != 0) ||
 535           (name_size != 0 && name_offset == 0)) {
 536         // If either is zero, both must be zero. This indicates that we are using the default base archive.
 537         log_warning(cds)("Invalid base_archive_name offset/size: " UINT32_FORMAT "/" UINT32_FORMAT,
 538                                    name_offset, name_size);
 539         return false;
 540       }
 541       if (name_size > 0) {
 542         if (name_offset + name_size > header_size) {
 543           log_warning(cds)("Invalid base_archive_name offset/size (out of range): "
 544                                      UINT32_FORMAT " + " UINT32_FORMAT " > " UINT32_FORMAT ,
 545                                      name_offset, name_size, header_size);
 546           return false;
 547         }
 548         const char* name = ((const char*)_header) + _header->_base_archive_name_offset;
 549         if (name[name_size - 1] != '\0' || strlen(name) != name_size - 1) {
 550           log_warning(cds)("Base archive name is damaged");
 551           return false;
 552         }
 553         if (!os::file_exists(name)) {
 554           log_warning(cds)("Base archive %s does not exist", name);
 555           return false;
 556         }
 557         _base_archive_name = name;
 558       }
 559     }
 560 
 561     return true;
 562   }
 563 };
 564 
 565 // Return value:
 566 // false:
 567 //      <archive_name> is not a valid archive. *base_archive_name is set to null.
 568 // true && (*base_archive_name) == nullptr:
 569 //      <archive_name> is a valid static archive.
 570 // true && (*base_archive_name) != nullptr:
 571 //      <archive_name> is a valid dynamic archive.
 572 bool FileMapInfo::get_base_archive_name_from_header(const char* archive_name,
 573                                                     char** base_archive_name) {
 574   FileHeaderHelper file_helper(archive_name, false);
 575   *base_archive_name = nullptr;
 576 
 577   if (!file_helper.initialize()) {
 578     return false;
 579   }
 580   GenericCDSFileMapHeader* header = file_helper.get_generic_file_header();
 581   switch (header->_magic) {
 582   case CDS_PREIMAGE_ARCHIVE_MAGIC:
 583     return false; // This is a binary config file, not a proper archive
 584   case CDS_DYNAMIC_ARCHIVE_MAGIC:
 585     break;
 586   default:
 587     assert(header->_magic == CDS_ARCHIVE_MAGIC, "must be");
 588     if (AutoCreateSharedArchive) {
 589      log_warning(cds)("AutoCreateSharedArchive is ignored because %s is a static archive", archive_name);
 590     }
 591     return true;
 592   }
 593 
 594   const char* base = file_helper.base_archive_name();
 595   if (base == nullptr) {
 596     *base_archive_name = CDSConfig::default_archive_path();
 597   } else {
 598     *base_archive_name = os::strdup_check_oom(base);
 599   }
 600 
 601   return true;
 602 }
 603 
 604 bool FileMapInfo::is_preimage_static_archive(const char* file) {
 605   FileHeaderHelper file_helper(file, false);
 606   if (!file_helper.initialize()) {
 607     return false;
 608   }
 609   return file_helper.is_preimage_static_archive();
 610 }
 611 
 612 // Read the FileMapInfo information from the file.
 613 
 614 bool FileMapInfo::init_from_file(int fd) {
 615   FileHeaderHelper file_helper(_full_path, _is_static);
 616   if (!file_helper.initialize(fd)) {
 617     log_warning(cds)("Unable to read the file header.");
 618     return false;
 619   }
 620   GenericCDSFileMapHeader* gen_header = file_helper.get_generic_file_header();
 621 
 622   const char* file_type = CDSConfig::type_of_archive_being_loaded();
 623   if (_is_static) {
 624     if ((gen_header->_magic == CDS_ARCHIVE_MAGIC) ||
 625         (gen_header->_magic == CDS_PREIMAGE_ARCHIVE_MAGIC && CDSConfig::is_dumping_final_static_archive())) {
 626       // Good
 627     } else {
 628       if (CDSConfig::new_aot_flags_used()) {
 629         log_warning(cds)("Not a valid %s %s", file_type, _full_path);
 630       } else {
 631         log_warning(cds)("Not a base shared archive: %s", _full_path);
 632       }
 633       return false;
 634     }
 635   } else {
 636     if (gen_header->_magic != CDS_DYNAMIC_ARCHIVE_MAGIC) {
 637       log_warning(cds)("Not a top shared archive: %s", _full_path);
 638       return false;
 639     }
 640   }
 641 
 642   _header = (FileMapHeader*)os::malloc(gen_header->_header_size, mtInternal);
 643   os::lseek(fd, 0, SEEK_SET); // reset to begin of the archive
 644   size_t size = gen_header->_header_size;
 645   size_t n = ::read(fd, (void*)_header, (unsigned int)size);
 646   if (n != size) {
 647     log_warning(cds)("Failed to read file header from the top archive file\n");
 648     return false;
 649   }
 650 
 651   if (header()->version() != CURRENT_CDS_ARCHIVE_VERSION) {
 652     log_info(cds)("_version expected: 0x%x", CURRENT_CDS_ARCHIVE_VERSION);
 653     log_info(cds)("           actual: 0x%x", header()->version());
 654     log_warning(cds)("The %s has the wrong version.", file_type);
 655     return false;
 656   }
 657 
 658   unsigned int base_offset = header()->base_archive_name_offset();
 659   unsigned int name_size = header()->base_archive_name_size();
 660   unsigned int header_size = header()->header_size();
 661   if (base_offset != 0 && name_size != 0) {
 662     if (header_size != base_offset + name_size) {
 663       log_info(cds)("_header_size: " UINT32_FORMAT, header_size);
 664       log_info(cds)("base_archive_name_size: " UINT32_FORMAT, header()->base_archive_name_size());
 665       log_info(cds)("base_archive_name_offset: " UINT32_FORMAT, header()->base_archive_name_offset());
 666       log_warning(cds)("The %s has an incorrect header size.", file_type);
 667       return false;
 668     }
 669   }
 670 
 671   const char* actual_ident = header()->jvm_ident();
 672 
 673   if (actual_ident[JVM_IDENT_MAX-1] != 0) {
 674     log_warning(cds)("JVM version identifier is corrupted.");
 675     return false;
 676   }
 677 
 678   char expected_ident[JVM_IDENT_MAX];
 679   get_header_version(expected_ident);
 680   if (strncmp(actual_ident, expected_ident, JVM_IDENT_MAX-1) != 0) {
 681     log_info(cds)("_jvm_ident expected: %s", expected_ident);
 682     log_info(cds)("             actual: %s", actual_ident);
 683     log_warning(cds)("The %s was created by a different"
 684                   " version or build of HotSpot", file_type);
 685     return false;
 686   }
 687 
 688   _file_offset = header()->header_size(); // accounts for the size of _base_archive_name
 689 
 690   size_t len = os::lseek(fd, 0, SEEK_END);
 691 
 692   for (int i = 0; i < MetaspaceShared::n_regions; i++) {
 693     FileMapRegion* r = region_at(i);
 694     if (r->file_offset() > len || len - r->file_offset() < r->used()) {
 695       log_warning(cds)("The %s has been truncated.", file_type);
 696       return false;
 697     }
 698   }
 699 
 700   return true;
 701 }
 702 
 703 void FileMapInfo::seek_to_position(size_t pos) {
 704   if (os::lseek(_fd, (long)pos, SEEK_SET) < 0) {
 705     log_error(cds)("Unable to seek to position %zu", pos);
 706     MetaspaceShared::unrecoverable_loading_error();
 707   }
 708 }
 709 
 710 // Read the FileMapInfo information from the file.
 711 bool FileMapInfo::open_for_read() {
 712   if (_file_open) {
 713     return true;
 714   }
 715   const char* file_type = CDSConfig::type_of_archive_being_loaded();
 716   const char* info = CDSConfig::is_dumping_final_static_archive() ?
 717     "AOTConfiguration file " : "";
 718   log_info(cds)("trying to map %s%s", info, _full_path);
 719   int fd = os::open(_full_path, O_RDONLY | O_BINARY, 0);
 720   if (fd < 0) {
 721     if (errno == ENOENT) {
 722       log_info(cds)("Specified %s not found (%s)", file_type, _full_path);
 723     } else {
 724       log_warning(cds)("Failed to open %s (%s)", file_type,
 725                     os::strerror(errno));
 726     }
 727     return false;
 728   } else {
 729     log_info(cds)("Opened %s %s.", file_type, _full_path);
 730   }
 731 
 732   _fd = fd;
 733   _file_open = true;
 734   return true;
 735 }
 736 
 737 // Write the FileMapInfo information to the file.
 738 
 739 void FileMapInfo::open_for_write() {
 740   LogMessage(cds) msg;
 741   if (msg.is_info()) {
 742     if (CDSConfig::is_dumping_preimage_static_archive()) {
 743       msg.info("Writing binary AOTConfiguration file: ");
 744     } else {
 745       msg.info("Dumping shared data to file: ");
 746     }
 747     msg.info("   %s", _full_path);
 748   }
 749 
 750 #ifdef _WINDOWS  // On Windows, need WRITE permission to remove the file.
 751   chmod(_full_path, _S_IREAD | _S_IWRITE);
 752 #endif
 753 
 754   // Use remove() to delete the existing file because, on Unix, this will
 755   // allow processes that have it open continued access to the file.
 756   remove(_full_path);
 757   int mode = CDSConfig::is_dumping_preimage_static_archive() ? 0666 : 0444;
 758   int fd = os::open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, mode);
 759   if (fd < 0) {
 760     log_error(cds)("Unable to create %s %s: (%s).", CDSConfig::type_of_archive_being_written(), _full_path,
 761                    os::strerror(errno));
 762     MetaspaceShared::writing_error();
 763     return;
 764   }
 765   _fd = fd;
 766   _file_open = true;
 767 
 768   // Seek past the header. We will write the header after all regions are written
 769   // and their CRCs computed.
 770   size_t header_bytes = header()->header_size();
 771 
 772   header_bytes = align_up(header_bytes, MetaspaceShared::core_region_alignment());
 773   _file_offset = header_bytes;
 774   seek_to_position(_file_offset);
 775 }
 776 
 777 // Write the header to the file, seek to the next allocation boundary.
 778 
 779 void FileMapInfo::write_header() {
 780   _file_offset = 0;
 781   seek_to_position(_file_offset);
 782   assert(is_file_position_aligned(), "must be");
 783   write_bytes(header(), header()->header_size());
 784 }
 785 
 786 size_t FileMapRegion::used_aligned() const {
 787   return align_up(used(), MetaspaceShared::core_region_alignment());
 788 }
 789 
 790 void FileMapRegion::init(int region_index, size_t mapping_offset, size_t size, bool read_only,
 791                          bool allow_exec, int crc) {
 792   _is_heap_region = HeapShared::is_heap_region(region_index);
 793   _is_bitmap_region = (region_index == MetaspaceShared::bm);
 794   _mapping_offset = mapping_offset;
 795   _used = size;
 796   _read_only = read_only;
 797   _allow_exec = allow_exec;
 798   _crc = crc;
 799   _mapped_from_file = false;
 800   _mapped_base = nullptr;
 801   _in_reserved_space = false;
 802 }
 803 
 804 void FileMapRegion::init_oopmap(size_t offset, size_t size_in_bits) {
 805   _oopmap_offset = offset;
 806   _oopmap_size_in_bits = size_in_bits;
 807 }
 808 
 809 void FileMapRegion::init_ptrmap(size_t offset, size_t size_in_bits) {
 810   _ptrmap_offset = offset;
 811   _ptrmap_size_in_bits = size_in_bits;
 812 }
 813 
 814 bool FileMapRegion::check_region_crc(char* base) const {
 815   // This function should be called after the region has been properly
 816   // loaded into memory via FileMapInfo::map_region() or FileMapInfo::read_region().
 817   // I.e., this->mapped_base() must be valid.
 818   size_t sz = used();
 819   if (sz == 0) {
 820     return true;
 821   }
 822 
 823   assert(base != nullptr, "must be initialized");
 824   int crc = ClassLoader::crc32(0, base, (jint)sz);
 825   if (crc != this->crc()) {
 826     log_warning(cds)("Checksum verification failed.");
 827     return false;
 828   }
 829   return true;
 830 }
 831 
 832 static const char* region_name(int region_index) {
 833   static const char* names[] = {
 834     "rw", "ro", "bm", "hp", "cc",
 835   };
 836   const int num_regions = sizeof(names)/sizeof(names[0]);
 837   assert(0 <= region_index && region_index < num_regions, "sanity");
 838 
 839   return names[region_index];
 840 }
 841 
 842 BitMapView FileMapInfo::bitmap_view(int region_index, bool is_oopmap) {
 843   FileMapRegion* r = region_at(region_index);
 844   char* bitmap_base = is_static() ? FileMapInfo::current_info()->map_bitmap_region() : FileMapInfo::dynamic_info()->map_bitmap_region();
 845   bitmap_base += is_oopmap ? r->oopmap_offset() : r->ptrmap_offset();
 846   size_t size_in_bits = is_oopmap ? r->oopmap_size_in_bits() : r->ptrmap_size_in_bits();
 847 
 848   log_debug(cds, reloc)("mapped %s relocation %smap @ " INTPTR_FORMAT " (%zu bits)",
 849                         region_name(region_index), is_oopmap ? "oop" : "ptr",
 850                         p2i(bitmap_base), size_in_bits);
 851 
 852   return BitMapView((BitMap::bm_word_t*)(bitmap_base), size_in_bits);
 853 }
 854 
 855 BitMapView FileMapInfo::oopmap_view(int region_index) {
 856     return bitmap_view(region_index, /*is_oopmap*/true);
 857   }
 858 
 859 BitMapView FileMapInfo::ptrmap_view(int region_index) {
 860   return bitmap_view(region_index, /*is_oopmap*/false);
 861 }
 862 
 863 void FileMapRegion::print(outputStream* st, int region_index) {
 864   st->print_cr("============ region ============= %d \"%s\"", region_index, region_name(region_index));
 865   st->print_cr("- crc:                            0x%08x", _crc);
 866   st->print_cr("- read_only:                      %d", _read_only);
 867   st->print_cr("- allow_exec:                     %d", _allow_exec);
 868   st->print_cr("- is_heap_region:                 %d", _is_heap_region);
 869   st->print_cr("- is_bitmap_region:               %d", _is_bitmap_region);
 870   st->print_cr("- mapped_from_file:               %d", _mapped_from_file);
 871   st->print_cr("- file_offset:                    0x%zx", _file_offset);
 872   st->print_cr("- mapping_offset:                 0x%zx", _mapping_offset);
 873   st->print_cr("- used:                           %zu", _used);
 874   st->print_cr("- oopmap_offset:                  0x%zx", _oopmap_offset);
 875   st->print_cr("- oopmap_size_in_bits:            %zu", _oopmap_size_in_bits);
 876   st->print_cr("- ptrmap_offset:                  0x%zx", _ptrmap_offset);
 877   st->print_cr("- ptrmap_size_in_bits:            %zu", _ptrmap_size_in_bits);
 878   st->print_cr("- mapped_base:                    " INTPTR_FORMAT, p2i(_mapped_base));
 879 }
 880 
 881 void FileMapInfo::write_region(int region, char* base, size_t size,
 882                                bool read_only, bool allow_exec) {
 883   assert(CDSConfig::is_dumping_archive(), "sanity");
 884 
 885   FileMapRegion* r = region_at(region);
 886   char* requested_base;
 887   size_t mapping_offset = 0;
 888 
 889   if (region == MetaspaceShared::bm) {
 890     requested_base = nullptr; // always null for bm region
 891   } else if (size == 0) {
 892     // This is an unused region (e.g., a heap region when !INCLUDE_CDS_JAVA_HEAP)
 893     requested_base = nullptr;
 894   } else if (HeapShared::is_heap_region(region)) {
 895     assert(CDSConfig::is_dumping_heap(), "sanity");
 896 #if INCLUDE_CDS_JAVA_HEAP
 897     assert(!CDSConfig::is_dumping_dynamic_archive(), "must be");
 898     requested_base = (char*)ArchiveHeapWriter::requested_address();
 899     if (UseCompressedOops) {
 900       mapping_offset = (size_t)((address)requested_base - CompressedOops::base());
 901       assert((mapping_offset >> CompressedOops::shift()) << CompressedOops::shift() == mapping_offset, "must be");
 902     } else {
 903       mapping_offset = 0; // not used with !UseCompressedOops
 904     }
 905 #endif // INCLUDE_CDS_JAVA_HEAP
 906   } else {
 907     char* requested_SharedBaseAddress = (char*)MetaspaceShared::requested_base_address();
 908     requested_base = ArchiveBuilder::current()->to_requested(base);
 909     assert(requested_base >= requested_SharedBaseAddress, "must be");
 910     mapping_offset = requested_base - requested_SharedBaseAddress;
 911   }
 912 
 913   r->set_file_offset(_file_offset);
 914   int crc = ClassLoader::crc32(0, base, (jint)size);
 915   if (size > 0) {
 916     log_info(cds)("Shared file region (%s) %d: %8zu"
 917                    " bytes, addr " INTPTR_FORMAT " file offset 0x%08" PRIxPTR
 918                    " crc 0x%08x",
 919                    region_name(region), region, size, p2i(requested_base), _file_offset, crc);
 920   } else {
 921     log_info(cds)("Shared file region (%s) %d: %8zu"
 922                   " bytes", region_name(region), region, size);
 923   }
 924 
 925   r->init(region, mapping_offset, size, read_only, allow_exec, crc);
 926 
 927   if (base != nullptr) {
 928     write_bytes_aligned(base, size);
 929   }
 930 }
 931 
 932 static size_t write_bitmap(const CHeapBitMap* map, char* output, size_t offset) {
 933   size_t size_in_bytes = map->size_in_bytes();
 934   map->write_to((BitMap::bm_word_t*)(output + offset), size_in_bytes);
 935   return offset + size_in_bytes;
 936 }
 937 
 938 // The sorting code groups the objects with non-null oop/ptrs together.
 939 // Relevant bitmaps then have lots of leading and trailing zeros, which
 940 // we do not have to store.
 941 size_t FileMapInfo::remove_bitmap_zeros(CHeapBitMap* map) {
 942   BitMap::idx_t first_set = map->find_first_set_bit(0);
 943   BitMap::idx_t last_set  = map->find_last_set_bit(0);
 944   size_t old_size = map->size();
 945 
 946   // Slice and resize bitmap
 947   map->truncate(first_set, last_set + 1);
 948 
 949   assert(map->at(0), "First bit should be set");
 950   assert(map->at(map->size() - 1), "Last bit should be set");
 951   assert(map->size() <= old_size, "sanity");
 952 
 953   return first_set;
 954 }
 955 
 956 char* FileMapInfo::write_bitmap_region(CHeapBitMap* rw_ptrmap, CHeapBitMap* ro_ptrmap,
 957                                        CHeapBitMap* cc_ptrmap,
 958                                        ArchiveHeapInfo* heap_info,
 959                                        size_t &size_in_bytes) {
 960   size_t removed_rw_leading_zeros = remove_bitmap_zeros(rw_ptrmap);
 961   size_t removed_ro_leading_zeros = remove_bitmap_zeros(ro_ptrmap);
 962   header()->set_rw_ptrmap_start_pos(removed_rw_leading_zeros);
 963   header()->set_ro_ptrmap_start_pos(removed_ro_leading_zeros);
 964   size_in_bytes = rw_ptrmap->size_in_bytes() + ro_ptrmap->size_in_bytes() + cc_ptrmap->size_in_bytes();
 965 
 966   if (heap_info->is_used()) {
 967     // Remove leading and trailing zeros
 968     size_t removed_oop_leading_zeros = remove_bitmap_zeros(heap_info->oopmap());
 969     size_t removed_ptr_leading_zeros = remove_bitmap_zeros(heap_info->ptrmap());
 970     header()->set_heap_oopmap_start_pos(removed_oop_leading_zeros);
 971     header()->set_heap_ptrmap_start_pos(removed_ptr_leading_zeros);
 972 
 973     size_in_bytes += heap_info->oopmap()->size_in_bytes();
 974     size_in_bytes += heap_info->ptrmap()->size_in_bytes();
 975   }
 976 
 977   // The bitmap region contains up to 4 parts:
 978   // rw_ptrmap:           metaspace pointers inside the read-write region
 979   // ro_ptrmap:           metaspace pointers inside the read-only region
 980   // heap_info->oopmap(): Java oop pointers in the heap region
 981   // heap_info->ptrmap(): metaspace pointers in the heap region
 982   char* buffer = NEW_C_HEAP_ARRAY(char, size_in_bytes, mtClassShared);
 983   size_t written = 0;
 984 
 985   region_at(MetaspaceShared::rw)->init_ptrmap(0, rw_ptrmap->size());
 986   written = write_bitmap(rw_ptrmap, buffer, written);
 987 
 988   region_at(MetaspaceShared::ro)->init_ptrmap(written, ro_ptrmap->size());
 989   written = write_bitmap(ro_ptrmap, buffer, written);
 990 
 991   region_at(MetaspaceShared::cc)->init_ptrmap(written, cc_ptrmap->size());
 992   written = write_bitmap(cc_ptrmap, buffer, written);
 993 
 994   if (heap_info->is_used()) {
 995     FileMapRegion* r = region_at(MetaspaceShared::hp);
 996 
 997     r->init_oopmap(written, heap_info->oopmap()->size());
 998     written = write_bitmap(heap_info->oopmap(), buffer, written);
 999 
1000     r->init_ptrmap(written, heap_info->ptrmap()->size());
1001     written = write_bitmap(heap_info->ptrmap(), buffer, written);
1002   }
1003 
1004   write_region(MetaspaceShared::bm, (char*)buffer, size_in_bytes, /*read_only=*/true, /*allow_exec=*/false);
1005   return buffer;
1006 }
1007 
1008 size_t FileMapInfo::write_heap_region(ArchiveHeapInfo* heap_info) {
1009   char* buffer_start = heap_info->buffer_start();
1010   size_t buffer_size = heap_info->buffer_byte_size();
1011   write_region(MetaspaceShared::hp, buffer_start, buffer_size, false, false);
1012   header()->set_heap_root_segments(heap_info->heap_root_segments());
1013   return buffer_size;
1014 }
1015 
1016 // Dump bytes to file -- at the current file position.
1017 
1018 void FileMapInfo::write_bytes(const void* buffer, size_t nbytes) {
1019   assert(_file_open, "must be");
1020   if (!os::write(_fd, buffer, nbytes)) {
1021     // If the shared archive is corrupted, close it and remove it.
1022     close();
1023     remove(_full_path);
1024 
1025     if (CDSConfig::is_dumping_preimage_static_archive()) {
1026       MetaspaceShared::writing_error("Unable to write to AOT configuration file.");
1027     } else if (CDSConfig::new_aot_flags_used()) {
1028       MetaspaceShared::writing_error("Unable to write to AOT cache.");
1029     } else {
1030       MetaspaceShared::writing_error("Unable to write to shared archive.");
1031     }
1032   }
1033   _file_offset += nbytes;
1034 }
1035 
1036 bool FileMapInfo::is_file_position_aligned() const {
1037   return _file_offset == align_up(_file_offset,
1038                                   MetaspaceShared::core_region_alignment());
1039 }
1040 
1041 // Align file position to an allocation unit boundary.
1042 
1043 void FileMapInfo::align_file_position() {
1044   assert(_file_open, "must be");
1045   size_t new_file_offset = align_up(_file_offset,
1046                                     MetaspaceShared::core_region_alignment());
1047   if (new_file_offset != _file_offset) {
1048     _file_offset = new_file_offset;
1049     // Seek one byte back from the target and write a byte to insure
1050     // that the written file is the correct length.
1051     _file_offset -= 1;
1052     seek_to_position(_file_offset);
1053     char zero = 0;
1054     write_bytes(&zero, 1);
1055   }
1056 }
1057 
1058 
1059 // Dump bytes to file -- at the current file position.
1060 
1061 void FileMapInfo::write_bytes_aligned(const void* buffer, size_t nbytes) {
1062   align_file_position();
1063   write_bytes(buffer, nbytes);
1064   align_file_position();
1065 }
1066 
1067 // Close the shared archive file.  This does NOT unmap mapped regions.
1068 
1069 void FileMapInfo::close() {
1070   if (_file_open) {
1071     if (::close(_fd) < 0) {
1072       MetaspaceShared::unrecoverable_loading_error("Unable to close the shared archive file.");
1073     }
1074     _file_open = false;
1075     _fd = -1;
1076   }
1077 }
1078 
1079 /*
1080  * Same as os::map_memory() but also pretouches if AlwaysPreTouch is enabled.
1081  */
1082 static char* map_memory(int fd, const char* file_name, size_t file_offset,
1083                         char *addr, size_t bytes, bool read_only,
1084                         bool allow_exec, MemTag mem_tag = mtNone) {
1085   char* mem = os::map_memory(fd, file_name, file_offset, addr, bytes,
1086                              AlwaysPreTouch ? false : read_only,
1087                              allow_exec, mem_tag);
1088   if (mem != nullptr && AlwaysPreTouch) {
1089     os::pretouch_memory(mem, mem + bytes);
1090   }
1091   return mem;
1092 }
1093 
1094 // JVM/TI RedefineClasses() support:
1095 // Remap the shared readonly space to shared readwrite, private.
1096 bool FileMapInfo::remap_shared_readonly_as_readwrite() {
1097   int idx = MetaspaceShared::ro;
1098   FileMapRegion* r = region_at(idx);
1099   if (!r->read_only()) {
1100     // the space is already readwrite so we are done
1101     return true;
1102   }
1103   size_t size = r->used_aligned();
1104   if (!open_for_read()) {
1105     return false;
1106   }
1107   char *addr = r->mapped_base();
1108   // This path should not be reached for Windows; see JDK-8222379.
1109   assert(WINDOWS_ONLY(false) NOT_WINDOWS(true), "Don't call on Windows");
1110   // Replace old mapping with new one that is writable.
1111   char *base = os::map_memory(_fd, _full_path, r->file_offset(),
1112                               addr, size, false /* !read_only */,
1113                               r->allow_exec());
1114   close();
1115   // These have to be errors because the shared region is now unmapped.
1116   if (base == nullptr) {
1117     log_error(cds)("Unable to remap shared readonly space (errno=%d).", errno);
1118     vm_exit(1);
1119   }
1120   if (base != addr) {
1121     log_error(cds)("Unable to remap shared readonly space (errno=%d).", errno);
1122     vm_exit(1);
1123   }
1124   r->set_read_only(false);
1125   return true;
1126 }
1127 
1128 // Memory map a region in the address space.
1129 static const char* shared_region_name[] = { "ReadWrite", "ReadOnly", "Bitmap", "Heap", "Code" };
1130 
1131 MapArchiveResult FileMapInfo::map_regions(int regions[], int num_regions, char* mapped_base_address, ReservedSpace rs) {
1132   DEBUG_ONLY(FileMapRegion* last_region = nullptr);
1133   intx addr_delta = mapped_base_address - header()->requested_base_address();
1134 
1135   // Make sure we don't attempt to use header()->mapped_base_address() unless
1136   // it's been successfully mapped.
1137   DEBUG_ONLY(header()->set_mapped_base_address((char*)(uintptr_t)0xdeadbeef);)
1138 
1139   for (int i = 0; i < num_regions; i++) {
1140     int idx = regions[i];
1141     MapArchiveResult result = map_region(idx, addr_delta, mapped_base_address, rs);
1142     if (result != MAP_ARCHIVE_SUCCESS) {
1143       return result;
1144     }
1145     FileMapRegion* r = region_at(idx);
1146     DEBUG_ONLY(if (last_region != nullptr) {
1147         // Ensure that the OS won't be able to allocate new memory spaces between any mapped
1148         // regions, or else it would mess up the simple comparison in MetaspaceObj::is_shared().
1149         assert(r->mapped_base() == last_region->mapped_end(), "must have no gaps");
1150       }
1151       last_region = r;)
1152     log_info(cds)("Mapped %s region #%d at base " INTPTR_FORMAT " top " INTPTR_FORMAT " (%s)", is_static() ? "static " : "dynamic",
1153                   idx, p2i(r->mapped_base()), p2i(r->mapped_end()),
1154                   shared_region_name[idx]);
1155 
1156   }
1157 
1158   header()->set_mapped_base_address(header()->requested_base_address() + addr_delta);
1159   if (addr_delta != 0 && !relocate_pointers_in_core_regions(addr_delta)) {
1160     return MAP_ARCHIVE_OTHER_FAILURE;
1161   }
1162 
1163   return MAP_ARCHIVE_SUCCESS;
1164 }
1165 
1166 bool FileMapInfo::read_region(int i, char* base, size_t size, bool do_commit) {
1167   FileMapRegion* r = region_at(i);
1168   if (do_commit) {
1169     log_info(cds)("Commit %s region #%d at base " INTPTR_FORMAT " top " INTPTR_FORMAT " (%s)%s",
1170                   is_static() ? "static " : "dynamic", i, p2i(base), p2i(base + size),
1171                   shared_region_name[i], r->allow_exec() ? " exec" : "");
1172     if (!os::commit_memory(base, size, r->allow_exec())) {
1173       log_error(cds)("Failed to commit %s region #%d (%s)", is_static() ? "static " : "dynamic",
1174                      i, shared_region_name[i]);
1175       return false;
1176     }
1177   }
1178   if (os::lseek(_fd, (long)r->file_offset(), SEEK_SET) != (int)r->file_offset() ||
1179       read_bytes(base, size) != size) {
1180     return false;
1181   }
1182 
1183   if (VerifySharedSpaces && !r->check_region_crc(base)) {
1184     return false;
1185   }
1186 
1187   r->set_mapped_from_file(false);
1188   r->set_mapped_base(base);
1189 
1190   return true;
1191 }
1192 
1193 MapArchiveResult FileMapInfo::map_region(int i, intx addr_delta, char* mapped_base_address, ReservedSpace rs) {
1194   assert(!HeapShared::is_heap_region(i), "sanity");
1195   FileMapRegion* r = region_at(i);
1196   size_t size = r->used_aligned();
1197   char *requested_addr = mapped_base_address + r->mapping_offset();
1198   assert(!is_mapped(), "must be not mapped yet");
1199   assert(requested_addr != nullptr, "must be specified");
1200 
1201   r->set_mapped_from_file(false);
1202   r->set_in_reserved_space(false);
1203 
1204   if (MetaspaceShared::use_windows_memory_mapping()) {
1205     // Windows cannot remap read-only shared memory to read-write when required for
1206     // RedefineClasses, which is also used by JFR.  Always map windows regions as RW.
1207     r->set_read_only(false);
1208   } else if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space() ||
1209              Arguments::has_jfr_option()) {
1210     // If a tool agent is in use (debugging enabled), or JFR, we must map the address space RW
1211     r->set_read_only(false);
1212   } else if (addr_delta != 0) {
1213     r->set_read_only(false); // Need to patch the pointers
1214   }
1215 
1216   if (MetaspaceShared::use_windows_memory_mapping() && rs.is_reserved()) {
1217     // This is the second time we try to map the archive(s). We have already created a ReservedSpace
1218     // that covers all the FileMapRegions to ensure all regions can be mapped. However, Windows
1219     // can't mmap into a ReservedSpace, so we just ::read() the data. We're going to patch all the
1220     // regions anyway, so there's no benefit for mmap anyway.
1221     if (!read_region(i, requested_addr, size, /* do_commit = */ true)) {
1222       log_info(cds)("Failed to read %s shared space into reserved space at " INTPTR_FORMAT,
1223                     shared_region_name[i], p2i(requested_addr));
1224       return MAP_ARCHIVE_OTHER_FAILURE; // oom or I/O error.
1225     } else {
1226       assert(r->mapped_base() != nullptr, "must be initialized");
1227     }
1228   } else {
1229     // Note that this may either be a "fresh" mapping into unreserved address
1230     // space (Windows, first mapping attempt), or a mapping into pre-reserved
1231     // space (Posix). See also comment in MetaspaceShared::map_archives().
1232     bool read_only = r->read_only() && !CDSConfig::is_dumping_final_static_archive();
1233     char* base = map_memory(_fd, _full_path, r->file_offset(),
1234                             requested_addr, size, read_only,
1235                             r->allow_exec(), mtClassShared);
1236     if (base != requested_addr) {
1237       log_info(cds)("Unable to map %s shared space at " INTPTR_FORMAT,
1238                     shared_region_name[i], p2i(requested_addr));
1239       _memory_mapping_failed = true;
1240       return MAP_ARCHIVE_MMAP_FAILURE;
1241     }
1242 
1243     if (VerifySharedSpaces && !r->check_region_crc(requested_addr)) {
1244       return MAP_ARCHIVE_OTHER_FAILURE;
1245     }
1246 
1247     r->set_mapped_from_file(true);
1248     r->set_mapped_base(requested_addr);
1249   }
1250 
1251   if (rs.is_reserved()) {
1252     char* mapped_base = r->mapped_base();
1253     assert(rs.base() <= mapped_base && mapped_base + size <= rs.end(),
1254            PTR_FORMAT " <= " PTR_FORMAT " < " PTR_FORMAT " <= " PTR_FORMAT,
1255            p2i(rs.base()), p2i(mapped_base), p2i(mapped_base + size), p2i(rs.end()));
1256     r->set_in_reserved_space(rs.is_reserved());
1257   }
1258   return MAP_ARCHIVE_SUCCESS;
1259 }
1260 
1261 // The return value is the location of the archive relocation bitmap.
1262 char* FileMapInfo::map_bitmap_region() {
1263   FileMapRegion* r = region_at(MetaspaceShared::bm);
1264   if (r->mapped_base() != nullptr) {
1265     return r->mapped_base();
1266   }
1267   bool read_only = true, allow_exec = false;
1268   char* requested_addr = nullptr; // allow OS to pick any location
1269   char* bitmap_base = map_memory(_fd, _full_path, r->file_offset(),
1270                                  requested_addr, r->used_aligned(), read_only, allow_exec, mtClassShared);
1271   if (bitmap_base == nullptr) {
1272     log_info(cds)("failed to map relocation bitmap");
1273     return nullptr;
1274   }
1275 
1276   if (VerifySharedSpaces && !r->check_region_crc(bitmap_base)) {
1277     log_error(cds)("relocation bitmap CRC error");
1278     if (!os::unmap_memory(bitmap_base, r->used_aligned())) {
1279       fatal("os::unmap_memory of relocation bitmap failed");
1280     }
1281     return nullptr;
1282   }
1283 
1284   r->set_mapped_from_file(true);
1285   r->set_mapped_base(bitmap_base);
1286   log_info(cds)("Mapped %s region #%d at base " INTPTR_FORMAT " top " INTPTR_FORMAT " (%s)",
1287                 is_static() ? "static " : "dynamic",
1288                 MetaspaceShared::bm, p2i(r->mapped_base()), p2i(r->mapped_end()),
1289                 shared_region_name[MetaspaceShared::bm]);
1290   return bitmap_base;
1291 }
1292 
1293 bool FileMapInfo::map_cached_code_region(ReservedSpace rs) {
1294   FileMapRegion* r = region_at(MetaspaceShared::cc);
1295   assert(r->used() > 0 && r->used_aligned() == rs.size(), "must be");
1296 
1297   char* requested_base = rs.base();
1298   assert(requested_base != nullptr, "should be inside code cache");
1299 
1300   char* mapped_base;
1301   if (MetaspaceShared::use_windows_memory_mapping()) {
1302     if (!read_region(MetaspaceShared::cc, requested_base, r->used_aligned(), /* do_commit = */ true)) {
1303       log_info(cds)("Failed to read cc shared space into reserved space at " INTPTR_FORMAT,
1304                     p2i(requested_base));
1305       return false;
1306     }
1307     mapped_base = requested_base;
1308   } else {
1309     bool read_only = false, allow_exec = false;
1310     mapped_base = map_memory(_fd, _full_path, r->file_offset(),
1311                              requested_base, r->used_aligned(), read_only, allow_exec, mtClassShared);
1312   }
1313   if (mapped_base == nullptr) {
1314     log_info(cds)("failed to map cached code region");
1315     return false;
1316   } else {
1317     assert(mapped_base == requested_base, "must be");
1318     r->set_mapped_from_file(true);
1319     r->set_mapped_base(mapped_base);
1320     relocate_pointers_in_cached_code_region();
1321     log_info(cds)("Mapped static  region #%d at base " INTPTR_FORMAT " top " INTPTR_FORMAT " (%s)",
1322                   MetaspaceShared::cc, p2i(r->mapped_base()), p2i(r->mapped_end()),
1323                   shared_region_name[MetaspaceShared::cc]);
1324     return true;
1325   }
1326 }
1327 
1328 class CachedCodeRelocator: public BitMapClosure {
1329   address _code_requested_base;
1330   address* _patch_base;
1331   intx _code_delta;
1332   intx _metadata_delta;
1333 
1334 public:
1335   CachedCodeRelocator(address code_requested_base, address code_mapped_base,
1336                       intx metadata_delta) {
1337     _code_requested_base = code_requested_base;
1338     _patch_base = (address*)code_mapped_base;
1339     _code_delta = code_mapped_base - code_requested_base;
1340     _metadata_delta = metadata_delta;
1341   }
1342   
1343   bool do_bit(size_t offset) {
1344     address* p = _patch_base + offset;
1345     address requested_ptr = *p;
1346     if (requested_ptr < _code_requested_base) {
1347       *p = requested_ptr + _metadata_delta;
1348     } else {
1349       *p = requested_ptr + _code_delta;
1350     }
1351     return true; // keep iterating
1352   }
1353 };
1354 
1355 void FileMapInfo::relocate_pointers_in_cached_code_region() {
1356   FileMapRegion* r = region_at(MetaspaceShared::cc);
1357   char* bitmap_base = map_bitmap_region();
1358 
1359   BitMapView cc_ptrmap = ptrmap_view(MetaspaceShared::cc);
1360   if (cc_ptrmap.size() == 0) {
1361     return;
1362   }
1363 
1364   address core_regions_requested_base = (address)header()->requested_base_address();
1365   address core_regions_mapped_base = (address)header()->mapped_base_address();
1366   address cc_region_requested_base = core_regions_requested_base + r->mapping_offset();
1367   address cc_region_mapped_base = (address)r->mapped_base();
1368 
1369   size_t max_bits_for_core_regions = pointer_delta(mapped_end(), mapped_base(), // FIXME - renamed to core_regions_mapped_base(), etc
1370                                                    sizeof(address));
1371 
1372   CachedCodeRelocator patcher(cc_region_requested_base, cc_region_mapped_base,
1373                               core_regions_mapped_base - core_regions_requested_base);
1374   cc_ptrmap.iterate(&patcher);
1375 }
1376 
1377 class SharedDataRelocationTask : public ArchiveWorkerTask {
1378 private:
1379   BitMapView* const _rw_bm;
1380   BitMapView* const _ro_bm;
1381   SharedDataRelocator* const _rw_reloc;
1382   SharedDataRelocator* const _ro_reloc;
1383 
1384 public:
1385   SharedDataRelocationTask(BitMapView* rw_bm, BitMapView* ro_bm, SharedDataRelocator* rw_reloc, SharedDataRelocator* ro_reloc) :
1386                            ArchiveWorkerTask("Shared Data Relocation"),
1387                            _rw_bm(rw_bm), _ro_bm(ro_bm), _rw_reloc(rw_reloc), _ro_reloc(ro_reloc) {}
1388 
1389   void work(int chunk, int max_chunks) override {
1390     work_on(chunk, max_chunks, _rw_bm, _rw_reloc);
1391     work_on(chunk, max_chunks, _ro_bm, _ro_reloc);
1392   }
1393 
1394   void work_on(int chunk, int max_chunks, BitMapView* bm, SharedDataRelocator* reloc) {
1395     BitMap::idx_t size  = bm->size();
1396     BitMap::idx_t start = MIN2(size, size * chunk / max_chunks);
1397     BitMap::idx_t end   = MIN2(size, size * (chunk + 1) / max_chunks);
1398     assert(end > start, "Sanity: no empty slices");
1399     bm->iterate(reloc, start, end);
1400   }
1401 };
1402 
1403 // This is called when we cannot map the archive at the requested[ base address (usually 0x800000000).
1404 // We relocate all pointers in the 2 core regions (ro, rw).
1405 bool FileMapInfo::relocate_pointers_in_core_regions(intx addr_delta) {
1406   log_debug(cds, reloc)("runtime archive relocation start");
1407   char* bitmap_base = map_bitmap_region();
1408 
1409   if (bitmap_base == nullptr) {
1410     return false; // OOM, or CRC check failure
1411   } else {
1412     BitMapView rw_ptrmap = ptrmap_view(MetaspaceShared::rw);
1413     BitMapView ro_ptrmap = ptrmap_view(MetaspaceShared::ro);
1414 
1415     FileMapRegion* rw_region = first_core_region();
1416     FileMapRegion* ro_region = last_core_region();
1417 
1418     // Patch all pointers inside the RW region
1419     address rw_patch_base = (address)rw_region->mapped_base();
1420     address rw_patch_end  = (address)rw_region->mapped_end();
1421 
1422     // Patch all pointers inside the RO region
1423     address ro_patch_base = (address)ro_region->mapped_base();
1424     address ro_patch_end  = (address)ro_region->mapped_end();
1425 
1426     // the current value of the pointers to be patched must be within this
1427     // range (i.e., must be between the requested base address and the address of the current archive).
1428     // Note: top archive may point to objects in the base archive, but not the other way around.
1429     address valid_old_base = (address)header()->requested_base_address();
1430     address valid_old_end  = valid_old_base + mapping_end_offset();
1431 
1432     // after patching, the pointers must point inside this range
1433     // (the requested location of the archive, as mapped at runtime).
1434     address valid_new_base = (address)header()->mapped_base_address();
1435     address valid_new_end  = (address)mapped_end();
1436 
1437     SharedDataRelocator rw_patcher((address*)rw_patch_base + header()->rw_ptrmap_start_pos(), (address*)rw_patch_end, valid_old_base, valid_old_end,
1438                                 valid_new_base, valid_new_end, addr_delta);
1439     SharedDataRelocator ro_patcher((address*)ro_patch_base + header()->ro_ptrmap_start_pos(), (address*)ro_patch_end, valid_old_base, valid_old_end,
1440                                 valid_new_base, valid_new_end, addr_delta);
1441 
1442     if (AOTCacheParallelRelocation) {
1443       ArchiveWorkers workers;
1444       SharedDataRelocationTask task(&rw_ptrmap, &ro_ptrmap, &rw_patcher, &ro_patcher);
1445       workers.run_task(&task);
1446     } else {
1447       rw_ptrmap.iterate(&rw_patcher);
1448       ro_ptrmap.iterate(&ro_patcher);
1449     }
1450 
1451     // The MetaspaceShared::bm region will be unmapped in MetaspaceShared::initialize_shared_spaces().
1452 
1453     log_debug(cds, reloc)("runtime archive relocation done");
1454     return true;
1455   }
1456 }
1457 
1458 size_t FileMapInfo::read_bytes(void* buffer, size_t count) {
1459   assert(_file_open, "Archive file is not open");
1460   size_t n = ::read(_fd, buffer, (unsigned int)count);
1461   if (n != count) {
1462     // Close the file if there's a problem reading it.
1463     close();
1464     return 0;
1465   }
1466   _file_offset += count;
1467   return count;
1468 }
1469 
1470 // Get the total size in bytes of a read only region
1471 size_t FileMapInfo::readonly_total() {
1472   size_t total = 0;
1473   if (current_info() != nullptr) {
1474     FileMapRegion* r = FileMapInfo::current_info()->region_at(MetaspaceShared::ro);
1475     if (r->read_only()) total += r->used();
1476   }
1477   if (dynamic_info() != nullptr) {
1478     FileMapRegion* r = FileMapInfo::dynamic_info()->region_at(MetaspaceShared::ro);
1479     if (r->read_only()) total += r->used();
1480   }
1481   return total;
1482 }
1483 
1484 #if INCLUDE_CDS_JAVA_HEAP
1485 MemRegion FileMapInfo::_mapped_heap_memregion;
1486 
1487 bool FileMapInfo::has_heap_region() {
1488   return (region_at(MetaspaceShared::hp)->used() > 0);
1489 }
1490 
1491 // Returns the address range of the archived heap region computed using the
1492 // current oop encoding mode. This range may be different than the one seen at
1493 // dump time due to encoding mode differences. The result is used in determining
1494 // if/how these regions should be relocated at run time.
1495 MemRegion FileMapInfo::get_heap_region_requested_range() {
1496   FileMapRegion* r = region_at(MetaspaceShared::hp);
1497   size_t size = r->used();
1498   assert(size > 0, "must have non-empty heap region");
1499 
1500   address start = heap_region_requested_address();
1501   address end = start + size;
1502   log_info(cds)("Requested heap region [" INTPTR_FORMAT " - " INTPTR_FORMAT "] = %8zu bytes",
1503                 p2i(start), p2i(end), size);
1504 
1505   return MemRegion((HeapWord*)start, (HeapWord*)end);
1506 }
1507 
1508 void FileMapInfo::map_or_load_heap_region() {
1509   bool success = false;
1510 
1511   if (can_use_heap_region()) {
1512     if (ArchiveHeapLoader::can_map()) {
1513       success = map_heap_region();
1514     } else if (ArchiveHeapLoader::can_load()) {
1515       success = ArchiveHeapLoader::load_heap_region(this);
1516     } else {
1517       if (!UseCompressedOops && !ArchiveHeapLoader::can_map()) {
1518         log_info(cds)("Cannot use CDS heap data. Selected GC not compatible -XX:-UseCompressedOops");
1519       } else {
1520         log_info(cds)("Cannot use CDS heap data. UseEpsilonGC, UseG1GC, UseSerialGC, UseParallelGC, or UseShenandoahGC are required.");
1521       }
1522     }
1523   }
1524 
1525   if (!success) {
1526     if (CDSConfig::is_using_aot_linked_classes() && !CDSConfig::is_dumping_final_static_archive()) {
1527       // It's too late to recover -- we have already committed to use the archived metaspace objects, but
1528       // the archived heap objects cannot be loaded, so we don't have the archived FMG to guarantee that
1529       // all AOT-linked classes are visible.
1530       //
1531       // We get here because the heap is too small. The app will fail anyway. So let's quit.
1532       MetaspaceShared::unrecoverable_loading_error("CDS archive has aot-linked classes but the archived "
1533                                                    "heap objects cannot be loaded. Try increasing your heap size.");
1534     }
1535     CDSConfig::stop_using_full_module_graph("archive heap loading failed");
1536   }
1537 }
1538 
1539 bool FileMapInfo::can_use_heap_region() {
1540   if (!has_heap_region()) {
1541     return false;
1542   }
1543   if (JvmtiExport::should_post_class_file_load_hook() && JvmtiExport::has_early_class_hook_env()) {
1544     ShouldNotReachHere(); // CDS should have been disabled.
1545     // The archived objects are mapped at JVM start-up, but we don't know if
1546     // j.l.String or j.l.Class might be replaced by the ClassFileLoadHook,
1547     // which would make the archived String or mirror objects invalid. Let's be safe and not
1548     // use the archived objects. These 2 classes are loaded during the JVMTI "early" stage.
1549     //
1550     // If JvmtiExport::has_early_class_hook_env() is false, the classes of some objects
1551     // in the archived subgraphs may be replaced by the ClassFileLoadHook. But that's OK
1552     // because we won't install an archived object subgraph if the klass of any of the
1553     // referenced objects are replaced. See HeapShared::initialize_from_archived_subgraph().
1554   }
1555 
1556   // We pre-compute narrow Klass IDs with the runtime mapping start intended to be the base, and a shift of
1557   // ArchiveBuilder::precomputed_narrow_klass_shift. We enforce this encoding at runtime (see
1558   // CompressedKlassPointers::initialize_for_given_encoding()). Therefore, the following assertions must
1559   // hold:
1560   address archive_narrow_klass_base = (address)header()->mapped_base_address();
1561   const int archive_narrow_klass_pointer_bits = header()->narrow_klass_pointer_bits();
1562   const int archive_narrow_klass_shift = header()->narrow_klass_shift();
1563 
1564   log_info(cds)("CDS archive was created with max heap size = %zuM, and the following configuration:",
1565                 max_heap_size()/M);
1566   log_info(cds)("    narrow_klass_base at mapping start address, narrow_klass_pointer_bits = %d, narrow_klass_shift = %d",
1567                 archive_narrow_klass_pointer_bits, archive_narrow_klass_shift);
1568   log_info(cds)("    narrow_oop_mode = %d, narrow_oop_base = " PTR_FORMAT ", narrow_oop_shift = %d",
1569                 narrow_oop_mode(), p2i(narrow_oop_base()), narrow_oop_shift());
1570   log_info(cds)("The current max heap size = %zuM, G1HeapRegion::GrainBytes = %zu",
1571                 MaxHeapSize/M, G1HeapRegion::GrainBytes);
1572   log_info(cds)("    narrow_klass_base = " PTR_FORMAT ", arrow_klass_pointer_bits = %d, narrow_klass_shift = %d",
1573                 p2i(CompressedKlassPointers::base()), CompressedKlassPointers::narrow_klass_pointer_bits(), CompressedKlassPointers::shift());
1574   log_info(cds)("    narrow_oop_mode = %d, narrow_oop_base = " PTR_FORMAT ", narrow_oop_shift = %d",
1575                 CompressedOops::mode(), p2i(CompressedOops::base()), CompressedOops::shift());
1576   log_info(cds)("    heap range = [" PTR_FORMAT " - "  PTR_FORMAT "]",
1577                 UseCompressedOops ? p2i(CompressedOops::begin()) :
1578                                     UseG1GC ? p2i((address)G1CollectedHeap::heap()->reserved().start()) : 0L,
1579                 UseCompressedOops ? p2i(CompressedOops::end()) :
1580                                     UseG1GC ? p2i((address)G1CollectedHeap::heap()->reserved().end()) : 0L);
1581 
1582   int err = 0;
1583   if ( archive_narrow_klass_base != CompressedKlassPointers::base() ||
1584        (err = 1, archive_narrow_klass_pointer_bits != CompressedKlassPointers::narrow_klass_pointer_bits()) ||
1585        (err = 2, archive_narrow_klass_shift != CompressedKlassPointers::shift()) ) {
1586     stringStream ss;
1587     switch (err) {
1588     case 0:
1589       ss.print("Unexpected encoding base encountered (" PTR_FORMAT ", expected " PTR_FORMAT ")",
1590                p2i(CompressedKlassPointers::base()), p2i(archive_narrow_klass_base));
1591       break;
1592     case 1:
1593       ss.print("Unexpected narrow Klass bit length encountered (%d, expected %d)",
1594                CompressedKlassPointers::narrow_klass_pointer_bits(), archive_narrow_klass_pointer_bits);
1595       break;
1596     case 2:
1597       ss.print("Unexpected narrow Klass shift encountered (%d, expected %d)",
1598                CompressedKlassPointers::shift(), archive_narrow_klass_shift);
1599       break;
1600     default:
1601       ShouldNotReachHere();
1602     };
1603     LogTarget(Info, cds) lt;
1604     if (lt.is_enabled()) {
1605       LogStream ls(lt);
1606       ls.print_raw(ss.base());
1607       header()->print(&ls);
1608     }
1609     assert(false, "%s", ss.base());
1610   }
1611 
1612   return true;
1613 }
1614 
1615 // The actual address of this region during dump time.
1616 address FileMapInfo::heap_region_dumptime_address() {
1617   FileMapRegion* r = region_at(MetaspaceShared::hp);
1618   assert(CDSConfig::is_using_archive(), "runtime only");
1619   assert(is_aligned(r->mapping_offset(), sizeof(HeapWord)), "must be");
1620   if (UseCompressedOops) {
1621     return /*dumptime*/ (address)((uintptr_t)narrow_oop_base() + r->mapping_offset());
1622   } else {
1623     return heap_region_requested_address();
1624   }
1625 }
1626 
1627 // The address where this region can be mapped into the runtime heap without
1628 // patching any of the pointers that are embedded in this region.
1629 address FileMapInfo::heap_region_requested_address() {
1630   assert(CDSConfig::is_using_archive(), "runtime only");
1631   FileMapRegion* r = region_at(MetaspaceShared::hp);
1632   assert(is_aligned(r->mapping_offset(), sizeof(HeapWord)), "must be");
1633   assert(ArchiveHeapLoader::can_use(), "GC must support mapping or loading");
1634   if (UseCompressedOops) {
1635     // We can avoid relocation if each region's offset from the runtime CompressedOops::base()
1636     // is the same as its offset from the CompressedOops::base() during dumptime.
1637     // Note that CompressedOops::base() may be different between dumptime and runtime.
1638     //
1639     // Example:
1640     // Dumptime base = 0x1000 and shift is 0. We have a region at address 0x2000. There's a
1641     // narrowOop P stored in this region that points to an object at address 0x2200.
1642     // P's encoded value is 0x1200.
1643     //
1644     // Runtime base = 0x4000 and shift is also 0. If we map this region at 0x5000, then
1645     // the value P can remain 0x1200. The decoded address = (0x4000 + (0x1200 << 0)) = 0x5200,
1646     // which is the runtime location of the referenced object.
1647     return /*runtime*/ (address)((uintptr_t)CompressedOops::base() + r->mapping_offset());
1648   } else {
1649     // This was the hard-coded requested base address used at dump time. With uncompressed oops,
1650     // the heap range is assigned by the OS so we will most likely have to relocate anyway, no matter
1651     // what base address was picked at duump time.
1652     return (address)ArchiveHeapWriter::NOCOOPS_REQUESTED_BASE;
1653   }
1654 }
1655 
1656 bool FileMapInfo::map_heap_region() {
1657   if (map_heap_region_impl()) {
1658 #ifdef ASSERT
1659     // The "old" regions must be parsable -- we cannot have any unused space
1660     // at the start of the lowest G1 region that contains archived objects.
1661     assert(is_aligned(_mapped_heap_memregion.start(), G1HeapRegion::GrainBytes), "must be");
1662 
1663     // Make sure we map at the very top of the heap - see comments in
1664     // init_heap_region_relocation().
1665     MemRegion heap_range = G1CollectedHeap::heap()->reserved();
1666     assert(heap_range.contains(_mapped_heap_memregion), "must be");
1667 
1668     address heap_end = (address)heap_range.end();
1669     address mapped_heap_region_end = (address)_mapped_heap_memregion.end();
1670     assert(heap_end >= mapped_heap_region_end, "must be");
1671     assert(heap_end - mapped_heap_region_end < (intx)(G1HeapRegion::GrainBytes),
1672            "must be at the top of the heap to avoid fragmentation");
1673 #endif
1674 
1675     ArchiveHeapLoader::set_mapped();
1676     return true;
1677   } else {
1678     return false;
1679   }
1680 }
1681 
1682 bool FileMapInfo::map_heap_region_impl() {
1683   assert(UseG1GC, "the following code assumes G1");
1684 
1685   FileMapRegion* r = region_at(MetaspaceShared::hp);
1686   size_t size = r->used();
1687   if (size == 0) {
1688     return false; // no archived java heap data
1689   }
1690 
1691   size_t word_size = size / HeapWordSize;
1692   address requested_start = heap_region_requested_address();
1693 
1694   log_info(cds)("Preferred address to map heap data (to avoid relocation) is " INTPTR_FORMAT, p2i(requested_start));
1695 
1696   // allocate from java heap
1697   HeapWord* start = G1CollectedHeap::heap()->alloc_archive_region(word_size, (HeapWord*)requested_start);
1698   if (start == nullptr) {
1699     log_info(cds)("UseSharedSpaces: Unable to allocate java heap region for archive heap.");
1700     return false;
1701   }
1702 
1703   _mapped_heap_memregion = MemRegion(start, word_size);
1704 
1705   // Map the archived heap data. No need to call MemTracker::record_virtual_memory_tag()
1706   // for mapped region as it is part of the reserved java heap, which is already recorded.
1707   char* addr = (char*)_mapped_heap_memregion.start();
1708   char* base;
1709 
1710   if (MetaspaceShared::use_windows_memory_mapping()) {
1711     if (!read_region(MetaspaceShared::hp, addr,
1712                      align_up(_mapped_heap_memregion.byte_size(), os::vm_page_size()),
1713                      /* do_commit = */ true)) {
1714       dealloc_heap_region();
1715       log_error(cds)("Failed to read archived heap region into " INTPTR_FORMAT, p2i(addr));
1716       return false;
1717     }
1718     // Checks for VerifySharedSpaces is already done inside read_region()
1719     base = addr;
1720   } else {
1721     base = map_memory(_fd, _full_path, r->file_offset(),
1722                       addr, _mapped_heap_memregion.byte_size(), r->read_only(),
1723                       r->allow_exec());
1724     if (base == nullptr || base != addr) {
1725       dealloc_heap_region();
1726       log_info(cds)("UseSharedSpaces: Unable to map at required address in java heap. "
1727                     INTPTR_FORMAT ", size = %zu bytes",
1728                     p2i(addr), _mapped_heap_memregion.byte_size());
1729       return false;
1730     }
1731 
1732     if (VerifySharedSpaces && !r->check_region_crc(base)) {
1733       dealloc_heap_region();
1734       log_info(cds)("UseSharedSpaces: mapped heap region is corrupt");
1735       return false;
1736     }
1737   }
1738 
1739   r->set_mapped_base(base);
1740 
1741   // If the requested range is different from the range allocated by GC, then
1742   // the pointers need to be patched.
1743   address mapped_start = (address) _mapped_heap_memregion.start();
1744   ptrdiff_t delta = mapped_start - requested_start;
1745   if (UseCompressedOops &&
1746       (narrow_oop_mode() != CompressedOops::mode() ||
1747        narrow_oop_shift() != CompressedOops::shift())) {
1748     _heap_pointers_need_patching = true;
1749   }
1750   if (delta != 0) {
1751     _heap_pointers_need_patching = true;
1752   }
1753   ArchiveHeapLoader::init_mapped_heap_info(mapped_start, delta, narrow_oop_shift());
1754 
1755   if (_heap_pointers_need_patching) {
1756     char* bitmap_base = map_bitmap_region();
1757     if (bitmap_base == nullptr) {
1758       log_info(cds)("CDS heap cannot be used because bitmap region cannot be mapped");
1759       dealloc_heap_region();
1760       _heap_pointers_need_patching = false;
1761       return false;
1762     }
1763   }
1764   log_info(cds)("Heap data mapped at " INTPTR_FORMAT ", size = %8zu bytes",
1765                 p2i(mapped_start), _mapped_heap_memregion.byte_size());
1766   log_info(cds)("CDS heap data relocation delta = %zd bytes", delta);
1767   return true;
1768 }
1769 
1770 narrowOop FileMapInfo::encoded_heap_region_dumptime_address() {
1771   assert(CDSConfig::is_using_archive(), "runtime only");
1772   assert(UseCompressedOops, "sanity");
1773   FileMapRegion* r = region_at(MetaspaceShared::hp);
1774   return CompressedOops::narrow_oop_cast(r->mapping_offset() >> narrow_oop_shift());
1775 }
1776 
1777 void FileMapInfo::patch_heap_embedded_pointers() {
1778   if (!ArchiveHeapLoader::is_mapped() || !_heap_pointers_need_patching) {
1779     return;
1780   }
1781 
1782   char* bitmap_base = map_bitmap_region();
1783   assert(bitmap_base != nullptr, "must have already been mapped");
1784 
1785   FileMapRegion* r = region_at(MetaspaceShared::hp);
1786   ArchiveHeapLoader::patch_embedded_pointers(
1787       this, _mapped_heap_memregion,
1788       (address)(region_at(MetaspaceShared::bm)->mapped_base()) + r->oopmap_offset(),
1789       r->oopmap_size_in_bits());
1790 }
1791 
1792 void FileMapInfo::fixup_mapped_heap_region() {
1793   if (ArchiveHeapLoader::is_mapped()) {
1794     assert(!_mapped_heap_memregion.is_empty(), "sanity");
1795 
1796     // Populate the archive regions' G1BlockOffsetTables. That ensures
1797     // fast G1BlockOffsetTable::block_start operations for any given address
1798     // within the archive regions when trying to find start of an object
1799     // (e.g. during card table scanning).
1800     G1CollectedHeap::heap()->populate_archive_regions_bot(_mapped_heap_memregion);
1801   }
1802 }
1803 
1804 // dealloc the archive regions from java heap
1805 void FileMapInfo::dealloc_heap_region() {
1806   G1CollectedHeap::heap()->dealloc_archive_regions(_mapped_heap_memregion);
1807 }
1808 #endif // INCLUDE_CDS_JAVA_HEAP
1809 
1810 void FileMapInfo::unmap_regions(int regions[], int num_regions) {
1811   for (int r = 0; r < num_regions; r++) {
1812     int idx = regions[r];
1813     unmap_region(idx);
1814   }
1815 }
1816 
1817 // Unmap a memory region in the address space.
1818 
1819 void FileMapInfo::unmap_region(int i) {
1820   FileMapRegion* r = region_at(i);
1821   char* mapped_base = r->mapped_base();
1822   size_t size = r->used_aligned();
1823 
1824   if (mapped_base != nullptr) {
1825     if (size > 0 && r->mapped_from_file()) {
1826       log_info(cds)("Unmapping region #%d at base " INTPTR_FORMAT " (%s)", i, p2i(mapped_base),
1827                     shared_region_name[i]);
1828       if (r->in_reserved_space()) {
1829         // This region was mapped inside a ReservedSpace. Its memory will be freed when the ReservedSpace
1830         // is released. Zero it so that we don't accidentally read its content.
1831         log_info(cds)("Region #%d (%s) is in a reserved space, it will be freed when the space is released", i, shared_region_name[i]);
1832       } else {
1833         if (!os::unmap_memory(mapped_base, size)) {
1834           fatal("os::unmap_memory failed");
1835         }
1836       }
1837     }
1838     r->set_mapped_base(nullptr);
1839   }
1840 }
1841 
1842 void FileMapInfo::assert_mark(bool check) {
1843   if (!check) {
1844     MetaspaceShared::unrecoverable_loading_error("Mark mismatch while restoring from shared file.");
1845   }
1846 }
1847 
1848 FileMapInfo* FileMapInfo::_current_info = nullptr;
1849 FileMapInfo* FileMapInfo::_dynamic_archive_info = nullptr;
1850 bool FileMapInfo::_heap_pointers_need_patching = false;
1851 bool FileMapInfo::_memory_mapping_failed = false;
1852 
1853 // Open the shared archive file, read and validate the header
1854 // information (version, boot classpath, etc.). If initialization
1855 // fails, shared spaces are disabled and the file is closed.
1856 //
1857 // Validation of the archive is done in two steps:
1858 //
1859 // [1] validate_header() - done here.
1860 // [2] validate_shared_path_table - this is done later, because the table is in the RO
1861 //     region of the archive, which is not mapped yet.
1862 bool FileMapInfo::initialize() {
1863   assert(CDSConfig::is_using_archive(), "UseSharedSpaces expected.");
1864   assert(Arguments::has_jimage(), "The shared archive file cannot be used with an exploded module build.");
1865 
1866   if (JvmtiExport::should_post_class_file_load_hook() && JvmtiExport::has_early_class_hook_env()) {
1867     // CDS assumes that no classes resolved in vmClasses::resolve_all()
1868     // are replaced at runtime by JVMTI ClassFileLoadHook. All of those classes are resolved
1869     // during the JVMTI "early" stage, so we can still use CDS if
1870     // JvmtiExport::has_early_class_hook_env() is false.
1871     log_info(cds)("CDS is disabled because early JVMTI ClassFileLoadHook is in use.");
1872     return false;
1873   }
1874 
1875   if (!open_for_read() || !init_from_file(_fd) || !validate_header()) {
1876     if (_is_static) {
1877       log_info(cds)("Initialize static archive failed.");
1878       return false;
1879     } else {
1880       log_info(cds)("Initialize dynamic archive failed.");
1881       if (AutoCreateSharedArchive) {
1882         CDSConfig::enable_dumping_dynamic_archive();
1883         ArchiveClassesAtExit = CDSConfig::dynamic_archive_path();
1884       }
1885       return false;
1886     }
1887   }
1888 
1889   return true;
1890 }
1891 
1892 bool FileMapInfo::validate_aot_class_linking() {
1893   // These checks need to be done after FileMapInfo::initialize(), which gets called before Universe::heap()
1894   // is available.
1895   if (header()->has_aot_linked_classes()) {
1896     CDSConfig::set_has_aot_linked_classes(true);
1897     if (JvmtiExport::should_post_class_file_load_hook()) {
1898       log_error(cds)("CDS archive has aot-linked classes. It cannot be used when JVMTI ClassFileLoadHook is in use.");
1899       return false;
1900     }
1901     if (JvmtiExport::has_early_vmstart_env()) {
1902       log_error(cds)("CDS archive has aot-linked classes. It cannot be used when JVMTI early vm start is in use.");
1903       return false;
1904     }
1905     if (!CDSConfig::is_using_full_module_graph() && !CDSConfig::is_dumping_final_static_archive()) {
1906       log_error(cds)("CDS archive has aot-linked classes. It cannot be used when archived full module graph is not used.");
1907       return false;
1908     }
1909 
1910     const char* prop = Arguments::get_property("java.security.manager");
1911     if (prop != nullptr && strcmp(prop, "disallow") != 0) {
1912       log_error(cds)("CDS archive has aot-linked classes. It cannot be used with -Djava.security.manager=%s.", prop);
1913       return false;
1914     }
1915 
1916     if (header()->gc_kind() != (int)Universe::heap()->kind()) {
1917       log_error(cds)("CDS archive has aot-linked classes. It cannot be used because GC used during dump time (%s) is not the same as runtime (%s)",
1918                      header()->gc_name(), Universe::heap()->name());
1919       return false;
1920     }
1921 
1922 #if INCLUDE_JVMTI
1923     if (Arguments::has_jdwp_agent()) {
1924       log_error(cds)("CDS archive has aot-linked classes. It cannot be used with JDWP agent");
1925       return false;
1926     }
1927 #endif
1928   }
1929 
1930   return true;
1931 }
1932 
1933 // The 2 core spaces are RW->RO
1934 FileMapRegion* FileMapInfo::first_core_region() const {
1935   return region_at(MetaspaceShared::rw);
1936 }
1937 
1938 FileMapRegion* FileMapInfo::last_core_region() const {
1939   return region_at(MetaspaceShared::ro);
1940 }
1941 
1942 void FileMapInfo::print(outputStream* st) const {
1943   header()->print(st);
1944   if (!is_static()) {
1945     dynamic_header()->print(st);
1946   }
1947 }
1948 
1949 void FileMapHeader::set_as_offset(char* p, size_t *offset) {
1950   *offset = ArchiveBuilder::current()->any_to_offset((address)p);
1951 }
1952 
1953 int FileMapHeader::compute_crc() {
1954   char* start = (char*)this;
1955   // start computing from the field after _header_size to end of base archive name.
1956   char* buf = (char*)&(_generic_header._header_size) + sizeof(_generic_header._header_size);
1957   size_t sz = header_size() - (buf - start);
1958   int crc = ClassLoader::crc32(0, buf, (jint)sz);
1959   return crc;
1960 }
1961 
1962 // This function should only be called during run time with UseSharedSpaces enabled.
1963 bool FileMapHeader::validate() {
1964   const char* file_type = CDSConfig::type_of_archive_being_loaded();
1965   if (_obj_alignment != ObjectAlignmentInBytes) {
1966     log_info(cds)("The %s's ObjectAlignmentInBytes of %d"
1967                   " does not equal the current ObjectAlignmentInBytes of %d.",
1968                   file_type, _obj_alignment, ObjectAlignmentInBytes);
1969     return false;
1970   }
1971   if (_compact_strings != CompactStrings) {
1972     log_info(cds)("The %s's CompactStrings setting (%s)"
1973                   " does not equal the current CompactStrings setting (%s).", file_type,
1974                   _compact_strings ? "enabled" : "disabled",
1975                   CompactStrings   ? "enabled" : "disabled");
1976     return false;
1977   }
1978 
1979   // This must be done after header validation because it might change the
1980   // header data
1981   const char* prop = Arguments::get_property("java.system.class.loader");
1982   if (prop != nullptr) {
1983     if (has_aot_linked_classes()) {
1984       log_error(cds)("CDS archive has aot-linked classes. It cannot be used when the "
1985                      "java.system.class.loader property is specified.");
1986       return false;
1987     }
1988     log_warning(cds)("Archived non-system classes are disabled because the "
1989             "java.system.class.loader property is specified (value = \"%s\"). "
1990             "To use archived non-system classes, this property must not be set", prop);
1991     _has_platform_or_app_classes = false;
1992   }
1993 
1994 
1995   if (!_verify_local && BytecodeVerificationLocal) {
1996     //  we cannot load boot classes, so there's no point of using the CDS archive
1997     log_info(cds)("The %s's BytecodeVerificationLocal setting (%s)"
1998                                " does not equal the current BytecodeVerificationLocal setting (%s).", file_type,
1999                                _verify_local ? "enabled" : "disabled",
2000                                BytecodeVerificationLocal ? "enabled" : "disabled");
2001     return false;
2002   }
2003 
2004   // For backwards compatibility, we don't check the BytecodeVerificationRemote setting
2005   // if the archive only contains system classes.
2006   if (_has_platform_or_app_classes
2007       && !_verify_remote // we didn't verify the archived platform/app classes
2008       && BytecodeVerificationRemote) { // but we want to verify all loaded platform/app classes
2009     log_info(cds)("The %s was created with less restrictive "
2010                                "verification setting than the current setting.", file_type);
2011     // Pretend that we didn't have any archived platform/app classes, so they won't be loaded
2012     // by SystemDictionaryShared.
2013     _has_platform_or_app_classes = false;
2014   }
2015 
2016   // Java agents are allowed during run time. Therefore, the following condition is not
2017   // checked: (!_allow_archiving_with_java_agent && AllowArchivingWithJavaAgent)
2018   // Note: _allow_archiving_with_java_agent is set in the shared archive during dump time
2019   // while AllowArchivingWithJavaAgent is set during the current run.
2020   if (_allow_archiving_with_java_agent && !AllowArchivingWithJavaAgent) {
2021     log_warning(cds)("The setting of the AllowArchivingWithJavaAgent is different "
2022                                "from the setting in the %s.", file_type);
2023     return false;
2024   }
2025 
2026   if (_allow_archiving_with_java_agent) {
2027     log_warning(cds)("This %s was created with AllowArchivingWithJavaAgent. It should be used "
2028             "for testing purposes only and should not be used in a production environment", file_type);
2029   }
2030 
2031   log_info(cds)("The %s was created with UseCompressedOops = %d, UseCompressedClassPointers = %d, UseCompactObjectHeaders = %d",
2032                           file_type, compressed_oops(), compressed_class_pointers(), compact_headers());
2033   if (compressed_oops() != UseCompressedOops || compressed_class_pointers() != UseCompressedClassPointers) {
2034     log_warning(cds)("Unable to use %s.\nThe saved state of UseCompressedOops and UseCompressedClassPointers is "
2035                                "different from runtime, CDS will be disabled.", file_type);
2036     return false;
2037   }
2038 
2039   if (compact_headers() != UseCompactObjectHeaders) {
2040     log_warning(cds)("Unable to use %s.\nThe %s's UseCompactObjectHeaders setting (%s)"
2041                      " does not equal the current UseCompactObjectHeaders setting (%s).", file_type, file_type,
2042                      _compact_headers          ? "enabled" : "disabled",
2043                      UseCompactObjectHeaders   ? "enabled" : "disabled");
2044     return false;
2045   }
2046 
2047   if (!_use_optimized_module_handling && !CDSConfig::is_dumping_final_static_archive()) {
2048     CDSConfig::stop_using_optimized_module_handling();
2049     log_info(cds)("optimized module handling: disabled because archive was created without optimized module handling");
2050   }
2051 
2052   if (is_static()) {
2053     // Only the static archive can contain the full module graph.
2054     if (!_has_full_module_graph) {
2055       CDSConfig::stop_using_full_module_graph("archive was created without full module graph");
2056     }
2057 
2058     if (_has_archived_packages) {
2059       CDSConfig::set_is_loading_packages();
2060     }
2061     if (_has_archived_protection_domains) {
2062       CDSConfig::set_is_loading_protection_domains();
2063     }
2064   }
2065 
2066   return true;
2067 }
2068 
2069 bool FileMapInfo::validate_header() {
2070   if (!header()->validate()) {
2071     return false;
2072   }
2073   if (_is_static) {
2074     return true;
2075   } else {
2076     return DynamicArchive::validate(this);
2077   }
2078 }
2079 
2080 #if INCLUDE_JVMTI
2081 ClassPathEntry** FileMapInfo::_classpath_entries_for_jvmti = nullptr;
2082 
2083 ClassPathEntry* FileMapInfo::get_classpath_entry_for_jvmti(int i, TRAPS) {
2084   if (i == 0) {
2085     // index 0 corresponds to the ClassPathImageEntry which is a globally shared object
2086     // and should never be deleted.
2087     return ClassLoader::get_jrt_entry();
2088   }
2089   ClassPathEntry* ent = _classpath_entries_for_jvmti[i];
2090   if (ent == nullptr) {
2091     const AOTClassLocation* cl = AOTClassLocationConfig::runtime()->class_location_at(i);
2092     const char* path = cl->path();
2093     struct stat st;
2094     if (os::stat(path, &st) != 0) {
2095       char *msg = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, strlen(path) + 128);
2096       jio_snprintf(msg, strlen(path) + 127, "error in finding JAR file %s", path);
2097       THROW_MSG_(vmSymbols::java_io_IOException(), msg, nullptr);
2098     } else {
2099       ent = ClassLoader::create_class_path_entry(THREAD, path, &st);
2100       if (ent == nullptr) {
2101         char *msg = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, strlen(path) + 128);
2102         jio_snprintf(msg, strlen(path) + 127, "error in opening JAR file %s", path);
2103         THROW_MSG_(vmSymbols::java_io_IOException(), msg, nullptr);
2104       }
2105     }
2106 
2107     MutexLocker mu(THREAD, CDSClassFileStream_lock);
2108     if (_classpath_entries_for_jvmti[i] == nullptr) {
2109       _classpath_entries_for_jvmti[i] = ent;
2110     } else {
2111       // Another thread has beat me to creating this entry
2112       delete ent;
2113       ent = _classpath_entries_for_jvmti[i];
2114     }
2115   }
2116 
2117   return ent;
2118 }
2119 
2120 ClassFileStream* FileMapInfo::open_stream_for_jvmti(InstanceKlass* ik, Handle class_loader, TRAPS) {
2121   int path_index = ik->shared_classpath_index();
2122   assert(path_index >= 0, "should be called for shared built-in classes only");
2123   assert(path_index < AOTClassLocationConfig::runtime()->length(), "sanity");
2124 
2125   ClassPathEntry* cpe = get_classpath_entry_for_jvmti(path_index, CHECK_NULL);
2126   assert(cpe != nullptr, "must be");
2127 
2128   Symbol* name = ik->name();
2129   const char* const class_name = name->as_C_string();
2130   const char* const file_name = ClassLoader::file_name_for_class_name(class_name,
2131                                                                       name->utf8_length());
2132   ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
2133   const AOTClassLocation* cl = AOTClassLocationConfig::runtime()->class_location_at(path_index);
2134   ClassFileStream* cfs;
2135   if (class_loader() != nullptr && cl->is_multi_release_jar()) {
2136     // This class was loaded from a multi-release JAR file during dump time. The
2137     // process for finding its classfile is complex. Let's defer to the Java code
2138     // in java.lang.ClassLoader.
2139     cfs = get_stream_from_class_loader(class_loader, cpe, file_name, CHECK_NULL);
2140   } else {
2141     cfs = cpe->open_stream_for_loader(THREAD, file_name, loader_data);
2142   }
2143   assert(cfs != nullptr, "must be able to read the classfile data of shared classes for built-in loaders.");
2144   log_debug(cds, jvmti)("classfile data for %s [%d: %s] = %d bytes", class_name, path_index,
2145                         cfs->source(), cfs->length());
2146   return cfs;
2147 }
2148 
2149 ClassFileStream* FileMapInfo::get_stream_from_class_loader(Handle class_loader,
2150                                                            ClassPathEntry* cpe,
2151                                                            const char* file_name,
2152                                                            TRAPS) {
2153   JavaValue result(T_OBJECT);
2154   oop class_name = java_lang_String::create_oop_from_str(file_name, THREAD);
2155   Handle h_class_name = Handle(THREAD, class_name);
2156 
2157   // byte[] ClassLoader.getResourceAsByteArray(String name)
2158   JavaCalls::call_virtual(&result,
2159                           class_loader,
2160                           vmClasses::ClassLoader_klass(),
2161                           vmSymbols::getResourceAsByteArray_name(),
2162                           vmSymbols::getResourceAsByteArray_signature(),
2163                           h_class_name,
2164                           CHECK_NULL);
2165   assert(result.get_type() == T_OBJECT, "just checking");
2166   oop obj = result.get_oop();
2167   assert(obj != nullptr, "ClassLoader.getResourceAsByteArray should not return null");
2168 
2169   // copy from byte[] to a buffer
2170   typeArrayOop ba = typeArrayOop(obj);
2171   jint len = ba->length();
2172   u1* buffer = NEW_RESOURCE_ARRAY(u1, len);
2173   ArrayAccess<>::arraycopy_to_native<>(ba, typeArrayOopDesc::element_offset<jbyte>(0), buffer, len);
2174 
2175   return new ClassFileStream(buffer, len, cpe->name());
2176 }
2177 #endif