1 /*
   2  * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_MEMORY_FILEMAP_HPP
  26 #define SHARE_VM_MEMORY_FILEMAP_HPP
  27 
  28 #include "memory/metaspaceShared.hpp"
  29 #include "memory/metaspace.hpp"
  30 
  31 // Layout of the file:
  32 //  header: dump of archive instance plus versioning info, datestamp, etc.
  33 //   [magic # = 0xF00BABA2]
  34 //  ... padding to align on page-boundary
  35 //  read-write space
  36 //  read-only space
  37 //  misc data (block offset table, string table, symbols, dictionary, etc.)
  38 //  tag(666)
  39 
  40 static const int JVM_IDENT_MAX = 256;
  41 
  42 class Metaspace;
  43 
  44 class SharedClassPathEntry VALUE_OBJ_CLASS_SPEC {
  45 public:
  46   const char *_name;
  47   time_t _timestamp;          // jar timestamp,  0 if is directory
  48   long   _filesize;           // jar file size, -1 if is directory



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