Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

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  */

 #ifndef SHARE_VM_MEMORY_FILEMAP_HPP

 #define SHARE_VM_MEMORY_FILEMAP_HPP

 #include "memory/metaspaceShared.hpp"

 #include "memory/metaspace.hpp"

 // Layout of the file:

 //  header: dump of archive instance plus versioning info, datestamp, etc.

 //   [magic # = 0xF00BABA2]

 //  ... padding to align on page-boundary

 //  read-write space from CompactingPermGenGen

 //  read-only space from CompactingPermGenGen

 //  misc data (block offset table, string table, symbols, dictionary, etc.)

 //  tag(666)

 static const int JVM_IDENT_MAX = 256;

 class Metaspace;

 class SharedClassPathEntry VALUE_OBJ_CLASS_SPEC {

 public:

   const char *_name;

   time_t _timestamp;          // jar timestamp,  0 if is directory

   long   _filesize;           // jar file size, -1 if is directory

   bool is_dir() {

     return _filesize == -1;

   }

 };

 class FileMapInfo : public CHeapObj<mtInternal> {

 private:

   friend class ManifestStream;

   enum {

     _invalid_version = -1,

     _current_version = 2

   };

   bool  _file_open;

   int   _fd;

   size_t  _file_offset;

 private:

   static SharedClassPathEntry* _classpath_entry_table;

   static int                   _classpath_entry_table_size;

   static size_t                _classpath_entry_size;

   static bool                  _validating_classpath_entry_table;

   // FileMapHeader describes the shared space data in the file to be

   // mapped.  This structure gets written to a file.  It is not a class, so

   // that the compilers don't add any compiler-private data to it.

 public:

   struct FileMapHeaderBase : public CHeapObj<mtClass> {

     virtual bool validate() = 0;

     virtual void populate(FileMapInfo* info, size_t alignment) = 0;

   };

   struct FileMapHeader : FileMapHeaderBase {

     // Use data() and data_size() to memcopy to/from the FileMapHeader. We need to

     // avoid read/writing the C++ vtable pointer.

     static size_t data_size();

     char* data() {

       return ((char*)this) + sizeof(FileMapHeaderBase);

     }

     int    _magic;                    // identify file type.

     int    _crc;                      // header crc checksum.

     int    _version;                  // (from enum, above.)

     size_t _alignment;                // how shared archive should be aligned

     int    _obj_alignment;            // value of ObjectAlignmentInBytes

     struct space_info {

       int    _crc;           // crc checksum of the current space

       size_t _file_offset;   // sizeof(this) rounded to vm page size

       char*  _base;          // copy-on-write base address

       size_t _capacity;      // for validity checking

       size_t _used;          // for setting space top on read

       bool   _read_only;     // read only space?

       bool   _allow_exec;    // executable code in space?

     } _space[MetaspaceShared::n_regions];

     // The following fields are all sanity checks for whether this archive

     // will function correctly with this JVM and the bootclasspath it's

     // invoked with.

     char  _jvm_ident[JVM_IDENT_MAX];      // identifier for jvm

     // The _paths_misc_info is a variable-size structure that records "miscellaneous"

     // information during dumping. It is generated and validated by the

     // SharedPathsMiscInfo class. See SharedPathsMiscInfo.hpp and sharedClassUtil.hpp for

     // detailed description.

     //

     // The _paths_misc_info data is stored as a byte array in the archive file header,

     // immediately after the _header field. This information is used only when

     // checking the validity of the archive and is deallocated after the archive is loaded.

     //

     // Note that the _paths_misc_info does NOT include information for JAR files

     // that existed during dump time. Their information is stored in _classpath_entry_table.

     int _paths_misc_info_size;

     // The following is a table of all the class path entries that were used

     // during dumping. At run time, we require these files to exist and have the same

     // size/modification time, or else the archive will refuse to load.

     //

     // All of these entries must be JAR files. The dumping process would fail if a non-empty

     // directory was specified in the classpaths. If an empty directory was specified

     // it is checked by the _paths_misc_info as described above.

     //

     // FIXME -- if JAR files in the tail of the list were specified but not used during dumping,

     // they should be removed from this table, to save space and to avoid spurious

     // loading failures during runtime.

     int _classpath_entry_table_size;

     size_t _classpath_entry_size;

     SharedClassPathEntry* _classpath_entry_table;

     virtual bool validate();

     virtual void populate(FileMapInfo* info, size_t alignment);

     int compute_crc();

   };

   FileMapHeader * _header;

   const char* _full_path;

   char* _paths_misc_info;

   static FileMapInfo* _current_info;

   bool  init_from_file(int fd);

   void  align_file_position();

   bool  validate_header_impl();

 public:

   FileMapInfo();

   ~FileMapInfo();

   static int current_version()        { return _current_version; }

   int    compute_header_crc();

   void   set_header_crc(int crc)      { _header->_crc = crc; }

   void   populate_header(size_t alignment);

   bool   validate_header();

   void   invalidate();

   int    version()                    { return _header->_version; }

   size_t alignment()                  { return _header->_alignment; }

   size_t space_capacity(int i)        { return _header->_space[i]._capacity; }

   char*  region_base(int i)           { return _header->_space[i]._base; }

   struct FileMapHeader* header()      { return _header; }

   static FileMapInfo* current_info() {

     CDS_ONLY(return _current_info;)

     NOT_CDS(return NULL;)

   }

   static void assert_mark(bool check);

   // File manipulation.

   bool  initialize() NOT_CDS_RETURN_(false);

   bool  open_for_read();

   void  open_for_write();

   void  write_header();

   void  write_space(int i, Metaspace* space, bool read_only);

   void  write_region(int region, char* base, size_t size,

                      size_t capacity, bool read_only, bool allow_exec);

   void  write_bytes(const void* buffer, int count);

   void  write_bytes_aligned(const void* buffer, int count);

   char* map_region(int i);

   void  unmap_region(int i);

   bool  verify_region_checksum(int i);

   void  close();

   bool  is_open() { return _file_open; }

   ReservedSpace reserve_shared_memory();

   // JVM/TI RedefineClasses() support:

   // Remap the shared readonly space to shared readwrite, private.

   bool  remap_shared_readonly_as_readwrite();

   // Errors.

   static void fail_stop(const char *msg, ...);

   static void fail_continue(const char *msg, ...);

   // Return true if given address is in the mapped shared space.

   bool is_in_shared_space(const void* p) NOT_CDS_RETURN_(false);

   void print_shared_spaces() NOT_CDS_RETURN;

   static size_t shared_spaces_size() {

     return align_size_up(SharedReadOnlySize + SharedReadWriteSize +

                          SharedMiscDataSize + SharedMiscCodeSize,

                          os::vm_allocation_granularity());

   }

   // Stop CDS sharing and unmap CDS regions.

   static void stop_sharing_and_unmap(const char* msg);

   static void allocate_classpath_entry_table();

   bool validate_classpath_entry_table();

   static SharedClassPathEntry* shared_classpath(int index) {

     char* p = (char*)_classpath_entry_table;

     p += _classpath_entry_size * index;

     return (SharedClassPathEntry*)p;

   }

   static const char* shared_classpath_name(int index) {

     return shared_classpath(index)->_name;

   }

   static int get_number_of_share_classpaths() {

     return _classpath_entry_table_size;

   }

 };

 #endif // SHARE_VM_MEMORY_FILEMAP_HPP