1 /*
   2  * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_MEMORY_FILEMAP_HPP
  26 #define SHARE_VM_MEMORY_FILEMAP_HPP
  27 
  28 #include "memory/metaspaceShared.hpp"
  29 #include "memory/metaspace.hpp"
  30 
  31 // Layout of the file:
  32 //  header: dump of archive instance plus versioning info, datestamp, etc.
  33 //   [magic # = 0xF00BABA2]
  34 //  ... padding to align on page-boundary
  35 //  read-write space
  36 //  read-only space
  37 //  misc data (block offset table, string table, symbols, dictionary, etc.)
  38 //  tag(666)
  39 
  40 static const int JVM_IDENT_MAX = 256;
  41 
  42 class Metaspace;
  43 
  44 class SharedClassPathEntry VALUE_OBJ_CLASS_SPEC {
  45 public:
  46   const char *_name;
  47   time_t _timestamp;          // jar/jimage timestamp,  0 if is directory or other
  48   long   _filesize;           // jar/jimage file size, -1 if is directory, -2 if other
  49 
  50   // The _timestamp only gets set for jar files and "modules" jimage.
  51   bool is_jar_or_bootimage() {
  52     return _timestamp != 0;
  53   }
  54   bool is_dir() {
  55     return _filesize == -1;
  56   }
  57 
  58   bool is_jrt() {
  59     return ClassLoader::is_jrt(_name);
  60   }
  61 };
  62 
  63 class FileMapInfo : public CHeapObj<mtInternal> {
  64 private:
  65   friend class ManifestStream;
  66   enum {
  67     _invalid_version = -1,
  68     _current_version = 2
  69   };
  70 
  71   bool  _file_open;
  72   int   _fd;
  73   size_t  _file_offset;
  74 
  75 private:
  76   static SharedClassPathEntry* _classpath_entry_table;
  77   static int                   _classpath_entry_table_size;
  78   static size_t                _classpath_entry_size;
  79   static bool                  _validating_classpath_entry_table;
  80 
  81   // FileMapHeader describes the shared space data in the file to be
  82   // mapped.  This structure gets written to a file.  It is not a class, so
  83   // that the compilers don't add any compiler-private data to it.
  84 
  85 public:
  86   struct FileMapHeaderBase : public CHeapObj<mtClass> {
  87     virtual bool validate() = 0;
  88     virtual void populate(FileMapInfo* info, size_t alignment) = 0;
  89   };
  90   struct FileMapHeader : FileMapHeaderBase {
  91     // Use data() and data_size() to memcopy to/from the FileMapHeader. We need to
  92     // avoid read/writing the C++ vtable pointer.
  93     static size_t data_size();
  94     char* data() {
  95       return ((char*)this) + sizeof(FileMapHeaderBase);
  96     }
  97 
  98     int    _magic;                    // identify file type.
  99     int    _crc;                      // header crc checksum.
 100     int    _version;                  // (from enum, above.)
 101     size_t _alignment;                // how shared archive should be aligned
 102     int    _obj_alignment;            // value of ObjectAlignmentInBytes
 103     int    _narrow_oop_shift;         // compressed oop encoding shift
 104     bool   _compact_strings;          // value of CompactStrings
 105     uintx  _max_heap_size;            // java max heap size during dumping
 106     Universe::NARROW_OOP_MODE _narrow_oop_mode; // compressed oop encoding mode
 107     int     _narrow_klass_shift;      // save narrow klass base and shift
 108     address _narrow_klass_base;
 109     char*   _misc_data_patching_start;
 110     address _cds_i2i_entry_code_buffers;
 111     size_t  _cds_i2i_entry_code_buffers_size;
 112 
 113     struct space_info {
 114       int    _crc;           // crc checksum of the current space
 115       size_t _file_offset;   // sizeof(this) rounded to vm page size
 116       union {
 117         char*  _base;        // copy-on-write base address
 118         intx   _offset;      // offset from the compressed oop encoding base, only used
 119                              // by string space
 120       } _addr;
 121       size_t _capacity;      // for validity checking
 122       size_t _used;          // for setting space top on read
 123       bool   _read_only;     // read only space?
 124       bool   _allow_exec;    // executable code in space?
 125     } _space[MetaspaceShared::n_regions];
 126 
 127     // The following fields are all sanity checks for whether this archive
 128     // will function correctly with this JVM and the bootclasspath it's
 129     // invoked with.
 130     char  _jvm_ident[JVM_IDENT_MAX];      // identifier for jvm
 131 
 132     // The _paths_misc_info is a variable-size structure that records "miscellaneous"
 133     // information during dumping. It is generated and validated by the
 134     // SharedPathsMiscInfo class. See SharedPathsMiscInfo.hpp and sharedClassUtil.hpp for
 135     // detailed description.
 136     //
 137     // The _paths_misc_info data is stored as a byte array in the archive file header,
 138     // immediately after the _header field. This information is used only when
 139     // checking the validity of the archive and is deallocated after the archive is loaded.
 140     //
 141     // Note that the _paths_misc_info does NOT include information for JAR files
 142     // that existed during dump time. Their information is stored in _classpath_entry_table.
 143     int _paths_misc_info_size;
 144 
 145     // The following is a table of all the class path entries that were used
 146     // during dumping. At run time, we require these files to exist and have the same
 147     // size/modification time, or else the archive will refuse to load.
 148     //
 149     // All of these entries must be JAR files. The dumping process would fail if a non-empty
 150     // directory was specified in the classpaths. If an empty directory was specified
 151     // it is checked by the _paths_misc_info as described above.
 152     //
 153     // FIXME -- if JAR files in the tail of the list were specified but not used during dumping,
 154     // they should be removed from this table, to save space and to avoid spurious
 155     // loading failures during runtime.
 156     int _classpath_entry_table_size;
 157     size_t _classpath_entry_size;
 158     SharedClassPathEntry* _classpath_entry_table;
 159 
 160     char* region_addr(int idx);
 161 
 162     virtual bool validate();
 163     virtual void populate(FileMapInfo* info, size_t alignment);
 164     int compute_crc();
 165   };
 166 
 167   FileMapHeader * _header;
 168 
 169   const char* _full_path;
 170   char* _paths_misc_info;
 171 
 172   static FileMapInfo* _current_info;
 173 
 174   bool  init_from_file(int fd);
 175   void  align_file_position();
 176   bool  validate_header_impl();
 177 
 178 public:
 179   FileMapInfo();
 180   ~FileMapInfo();
 181 
 182   static int current_version()        { return _current_version; }
 183   int    compute_header_crc()         { return _header->compute_crc(); }
 184   void   set_header_crc(int crc)      { _header->_crc = crc; }
 185   void   populate_header(size_t alignment);
 186   bool   validate_header();
 187   void   invalidate();
 188   int    version()                    { return _header->_version; }
 189   size_t alignment()                  { return _header->_alignment; }
 190   Universe::NARROW_OOP_MODE narrow_oop_mode() { return _header->_narrow_oop_mode; }
 191   int    narrow_oop_shift()           { return _header->_narrow_oop_shift; }
 192   uintx  max_heap_size()              { return _header->_max_heap_size; }
 193   address narrow_klass_base() const   { return _header->_narrow_klass_base; }
 194   int     narrow_klass_shift() const  { return _header->_narrow_klass_shift; }
 195   size_t space_capacity(int i)        { return _header->_space[i]._capacity; }
 196   struct FileMapHeader* header()      { return _header; }
 197   char* misc_data_patching_start()            { return _header->_misc_data_patching_start; }
 198   void set_misc_data_patching_start(char* p)  { _header->_misc_data_patching_start = p; }
 199 
 200   address cds_i2i_entry_code_buffers() {
 201     return _header->_cds_i2i_entry_code_buffers;
 202   }
 203   void set_cds_i2i_entry_code_buffers(address addr) {
 204     _header->_cds_i2i_entry_code_buffers = addr;
 205   }
 206   size_t cds_i2i_entry_code_buffers_size() {
 207     return _header->_cds_i2i_entry_code_buffers_size;
 208   }
 209   void set_cds_i2i_entry_code_buffers_size(size_t s) {
 210     _header->_cds_i2i_entry_code_buffers_size = s;
 211   }
 212 
 213   static FileMapInfo* current_info() {
 214     CDS_ONLY(return _current_info;)
 215     NOT_CDS(return NULL;)
 216   }
 217 
 218   static void assert_mark(bool check);
 219 
 220   // File manipulation.
 221   bool  initialize() NOT_CDS_RETURN_(false);
 222   bool  open_for_read();
 223   void  open_for_write();
 224   void  write_header();
 225   void  write_space(int i, Metaspace* space, bool read_only);
 226   void  write_region(int region, char* base, size_t size,
 227                      size_t capacity, bool read_only, bool allow_exec);
 228   void  write_string_regions(GrowableArray<MemRegion> *regions);
 229   void  write_bytes(const void* buffer, int count);
 230   void  write_bytes_aligned(const void* buffer, int count);
 231   char* map_region(int i);
 232   bool  map_string_regions();
 233   bool  verify_string_regions();
 234   void  fixup_string_regions();
 235   void  unmap_region(int i);
 236   void  dealloc_string_regions();
 237   bool  verify_region_checksum(int i);
 238   void  close();
 239   bool  is_open() { return _file_open; }
 240   ReservedSpace reserve_shared_memory();
 241 
 242   // JVM/TI RedefineClasses() support:
 243   // Remap the shared readonly space to shared readwrite, private.
 244   bool  remap_shared_readonly_as_readwrite();
 245 
 246   // Errors.
 247   static void fail_stop(const char *msg, ...) ATTRIBUTE_PRINTF(1, 2);
 248   static void fail_continue(const char *msg, ...) ATTRIBUTE_PRINTF(1, 2);
 249 
 250   // Return true if given address is in the mapped shared space.
 251   bool is_in_shared_space(const void* p) NOT_CDS_RETURN_(false);
 252   bool is_in_shared_region(const void* p, int idx) NOT_CDS_RETURN_(false);
 253   void print_shared_spaces() NOT_CDS_RETURN;
 254 
 255   // The ro+rw+md+mc spaces size
 256   static size_t core_spaces_size() {
 257     return align_size_up((SharedReadOnlySize + SharedReadWriteSize +
 258                           SharedMiscDataSize + SharedMiscCodeSize),
 259                           os::vm_allocation_granularity());
 260   }
 261 
 262   // The estimated optional space size.
 263   //
 264   // Currently the optional space only has archived class bytes.
 265   // The core_spaces_size is the size of all class metadata, which is a good
 266   // estimate of the total class bytes to be archived. Only the portion
 267   // containing data is written out to the archive and mapped at runtime.
 268   // There is no memory waste due to unused portion in optional space.
 269   static size_t optional_space_size() {
 270     return core_spaces_size();
 271   }
 272 
 273   // Total shared_spaces size includes the ro, rw, md, mc and od spaces
 274   static size_t shared_spaces_size() {
 275     return core_spaces_size() + optional_space_size();
 276   }
 277 
 278   // Stop CDS sharing and unmap CDS regions.
 279   static void stop_sharing_and_unmap(const char* msg);
 280 
 281   static void allocate_classpath_entry_table();
 282   bool validate_classpath_entry_table();
 283 
 284   static SharedClassPathEntry* shared_classpath(int index) {
 285     if (index < 0) {
 286       return NULL;
 287     }
 288     char* p = (char*)_classpath_entry_table;
 289     p += _classpath_entry_size * index;
 290     return (SharedClassPathEntry*)p;
 291   }
 292   static const char* shared_classpath_name(int index) {
 293     assert(index >= 0, "Sanity");
 294     return shared_classpath(index)->_name;
 295   }
 296 
 297   static int get_number_of_share_classpaths() {
 298     return _classpath_entry_table_size;
 299   }
 300 };
 301 
 302 #endif // SHARE_VM_MEMORY_FILEMAP_HPP