1 /*
   2  * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_MEMORY_FILEMAP_HPP
  26 #define SHARE_VM_MEMORY_FILEMAP_HPP
  27 
  28 #include "memory/metaspaceShared.hpp"
  29 #include "memory/metaspace.hpp"
  30 
  31 // Layout of the file:
  32 //  header: dump of archive instance plus versioning info, datestamp, etc.
  33 //   [magic # = 0xF00BABA2]
  34 //  ... padding to align on page-boundary
  35 //  read-write space
  36 //  read-only space
  37 //  misc data (block offset table, string table, symbols, dictionary, etc.)
  38 //  tag(666)
  39 
  40 static const int JVM_IDENT_MAX = 256;
  41 
  42 class Metaspace;
  43 
  44 class SharedClassPathEntry VALUE_OBJ_CLASS_SPEC {
  45 public:
  46   const char *_name;
  47   time_t _timestamp;          // jar timestamp,  0 if is directory or other
  48   long   _filesize;           // jar file size, -1 if is directory, -2 if other
  49   bool is_jar() {
  50     return _timestamp != 0;
  51   }
  52   bool is_dir() {
  53     return _filesize == -1;
  54   }
  55 };
  56 
  57 class FileMapInfo : public CHeapObj<mtInternal> {
  58 private:
  59   friend class ManifestStream;
  60   enum {
  61     _invalid_version = -1,
  62     _current_version = 2
  63   };
  64 
  65   bool  _file_open;
  66   int   _fd;
  67   size_t  _file_offset;
  68 
  69 private:
  70   static SharedClassPathEntry* _classpath_entry_table;
  71   static int                   _classpath_entry_table_size;
  72   static size_t                _classpath_entry_size;
  73   static bool                  _validating_classpath_entry_table;
  74 
  75   // FileMapHeader describes the shared space data in the file to be
  76   // mapped.  This structure gets written to a file.  It is not a class, so
  77   // that the compilers don't add any compiler-private data to it.
  78 
  79 public:
  80   struct FileMapHeaderBase : public CHeapObj<mtClass> {
  81     virtual bool validate() = 0;
  82     virtual void populate(FileMapInfo* info, size_t alignment) = 0;
  83   };
  84   struct FileMapHeader : FileMapHeaderBase {
  85     // Use data() and data_size() to memcopy to/from the FileMapHeader. We need to
  86     // avoid read/writing the C++ vtable pointer.
  87     static size_t data_size();
  88     char* data() {
  89       return ((char*)this) + sizeof(FileMapHeaderBase);
  90     }
  91 
  92     int    _magic;                    // identify file type.
  93     int    _crc;                      // header crc checksum.
  94     int    _version;                  // (from enum, above.)
  95     size_t _alignment;                // how shared archive should be aligned
  96     int    _obj_alignment;            // value of ObjectAlignmentInBytes
  97     int    _narrow_oop_shift;         // compressed oop encoding shift
  98     bool   _compact_strings;          // value of CompactStrings
  99     uintx  _max_heap_size;            // java max heap size during dumping
 100     Universe::NARROW_OOP_MODE _narrow_oop_mode; // compressed oop encoding mode
 101     int     _narrow_klass_shift;      // save narrow klass base and shift
 102     address _narrow_klass_base;
 103 
 104     struct space_info {
 105       int    _crc;           // crc checksum of the current space
 106       size_t _file_offset;   // sizeof(this) rounded to vm page size
 107       union {
 108         char*  _base;        // copy-on-write base address
 109         intx   _offset;      // offset from the compressed oop encoding base, only used
 110                              // by string space
 111       } _addr;
 112       size_t _capacity;      // for validity checking
 113       size_t _used;          // for setting space top on read
 114       bool   _read_only;     // read only space?
 115       bool   _allow_exec;    // executable code in space?
 116     } _space[MetaspaceShared::n_regions];
 117 
 118     // The following fields are all sanity checks for whether this archive
 119     // will function correctly with this JVM and the bootclasspath it's
 120     // invoked with.
 121     char  _jvm_ident[JVM_IDENT_MAX];      // identifier for jvm
 122 
 123     // The _paths_misc_info is a variable-size structure that records "miscellaneous"
 124     // information during dumping. It is generated and validated by the
 125     // SharedPathsMiscInfo class. See SharedPathsMiscInfo.hpp and sharedClassUtil.hpp for
 126     // detailed description.
 127     //
 128     // The _paths_misc_info data is stored as a byte array in the archive file header,
 129     // immediately after the _header field. This information is used only when
 130     // checking the validity of the archive and is deallocated after the archive is loaded.
 131     //
 132     // Note that the _paths_misc_info does NOT include information for JAR files
 133     // that existed during dump time. Their information is stored in _classpath_entry_table.
 134     int _paths_misc_info_size;
 135 
 136     // The following is a table of all the class path entries that were used
 137     // during dumping. At run time, we require these files to exist and have the same
 138     // size/modification time, or else the archive will refuse to load.
 139     //
 140     // All of these entries must be JAR files. The dumping process would fail if a non-empty
 141     // directory was specified in the classpaths. If an empty directory was specified
 142     // it is checked by the _paths_misc_info as described above.
 143     //
 144     // FIXME -- if JAR files in the tail of the list were specified but not used during dumping,
 145     // they should be removed from this table, to save space and to avoid spurious
 146     // loading failures during runtime.
 147     int _classpath_entry_table_size;
 148     size_t _classpath_entry_size;
 149     SharedClassPathEntry* _classpath_entry_table;
 150 
 151     char* region_addr(int idx);
 152 
 153     virtual bool validate();
 154     virtual void populate(FileMapInfo* info, size_t alignment);
 155     int compute_crc();
 156   };
 157 
 158   FileMapHeader * _header;
 159 
 160   const char* _full_path;
 161   char* _paths_misc_info;
 162 
 163   static FileMapInfo* _current_info;
 164 
 165   bool  init_from_file(int fd);
 166   void  align_file_position();
 167   bool  validate_header_impl();
 168 
 169 public:
 170   FileMapInfo();
 171   ~FileMapInfo();
 172 
 173   static int current_version()        { return _current_version; }
 174   int    compute_header_crc()         { return _header->compute_crc(); }
 175   void   set_header_crc(int crc)      { _header->_crc = crc; }
 176   void   populate_header(size_t alignment);
 177   bool   validate_header();
 178   void   invalidate();
 179   int    version()                    { return _header->_version; }
 180   size_t alignment()                  { return _header->_alignment; }
 181   Universe::NARROW_OOP_MODE narrow_oop_mode() { return _header->_narrow_oop_mode; }
 182   int    narrow_oop_shift()           { return _header->_narrow_oop_shift; }
 183   uintx  max_heap_size()              { return _header->_max_heap_size; }
 184   address narrow_klass_base() const   { return _header->_narrow_klass_base; }
 185   int     narrow_klass_shift() const  { return _header->_narrow_klass_shift; }
 186   size_t space_capacity(int i)        { return _header->_space[i]._capacity; }
 187   struct FileMapHeader* header()      { return _header; }
 188 
 189   static FileMapInfo* current_info() {
 190     CDS_ONLY(return _current_info;)
 191     NOT_CDS(return NULL;)
 192   }
 193 
 194   static void assert_mark(bool check);
 195 
 196   // File manipulation.
 197   bool  initialize() NOT_CDS_RETURN_(false);
 198   bool  open_for_read();
 199   void  open_for_write();
 200   void  write_header();
 201   void  write_space(int i, Metaspace* space, bool read_only);
 202   void  write_region(int region, char* base, size_t size,
 203                      size_t capacity, bool read_only, bool allow_exec);
 204   void  write_string_regions(GrowableArray<MemRegion> *regions);
 205   void  write_bytes(const void* buffer, int count);
 206   void  write_bytes_aligned(const void* buffer, int count);
 207   char* map_region(int i);
 208   bool  map_string_regions();
 209   bool  verify_string_regions();
 210   void  fixup_string_regions();
 211   void  unmap_region(int i);
 212   void  dealloc_string_regions();
 213   bool  verify_region_checksum(int i);
 214   void  close();
 215   bool  is_open() { return _file_open; }
 216   ReservedSpace reserve_shared_memory();
 217 
 218   // JVM/TI RedefineClasses() support:
 219   // Remap the shared readonly space to shared readwrite, private.
 220   bool  remap_shared_readonly_as_readwrite();
 221 
 222   // Errors.
 223   static void fail_stop(const char *msg, ...) ATTRIBUTE_PRINTF(1, 2);
 224   static void fail_continue(const char *msg, ...) ATTRIBUTE_PRINTF(1, 2);
 225 
 226   // Return true if given address is in the mapped shared space.
 227   bool is_in_shared_space(const void* p) NOT_CDS_RETURN_(false);
 228   void print_shared_spaces() NOT_CDS_RETURN;
 229 
 230   static size_t shared_spaces_size() {
 231     return align_size_up(SharedReadOnlySize + SharedReadWriteSize +
 232                          SharedMiscDataSize + SharedMiscCodeSize,
 233                          os::vm_allocation_granularity());
 234   }
 235 
 236   // Stop CDS sharing and unmap CDS regions.
 237   static void stop_sharing_and_unmap(const char* msg);
 238 
 239   static void allocate_classpath_entry_table();
 240   bool validate_classpath_entry_table();
 241 
 242   static SharedClassPathEntry* shared_classpath(int index) {
 243     char* p = (char*)_classpath_entry_table;
 244     p += _classpath_entry_size * index;
 245     return (SharedClassPathEntry*)p;
 246   }
 247   static const char* shared_classpath_name(int index) {
 248     return shared_classpath(index)->_name;
 249   }
 250 
 251   static int get_number_of_share_classpaths() {
 252     return _classpath_entry_table_size;
 253   }
 254 };
 255 
 256 #endif // SHARE_VM_MEMORY_FILEMAP_HPP