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Java example source code file (elfFile.hpp)

This example Java source code file (elfFile.hpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

elf_addr, elf_ehdr, elf_half, elf_off, elf_phdr, elf_shdr, elf_st_type, elf_sym, elf_word, elffile, elfstringtable, elfsymboltable, nulldecoder\:\:decoder_status, share_vm_utilities_elf_file_hpp

The elfFile.hpp Java example source code

/*
 * Copyright (c) 1997, 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.
 *
 */

#ifndef SHARE_VM_UTILITIES_ELF_FILE_HPP
#define SHARE_VM_UTILITIES_ELF_FILE_HPP

#if !defined(_WINDOWS) && !defined(__APPLE__)

#if defined(__OpenBSD__)
#include <sys/exec_elf.h>
#else
#include <elf.h>
#endif
#include <stdio.h>

#ifdef _LP64

typedef Elf64_Half      Elf_Half;
typedef Elf64_Word      Elf_Word;
typedef Elf64_Off       Elf_Off;
typedef Elf64_Addr      Elf_Addr;

typedef Elf64_Ehdr      Elf_Ehdr;
typedef Elf64_Shdr      Elf_Shdr;
typedef Elf64_Phdr      Elf_Phdr;
typedef Elf64_Sym       Elf_Sym;

#if !defined(_ALLBSD_SOURCE) || defined(__APPLE__)
#define ELF_ST_TYPE ELF64_ST_TYPE
#endif

#else

typedef Elf32_Half      Elf_Half;
typedef Elf32_Word      Elf_Word;
typedef Elf32_Off       Elf_Off;
typedef Elf32_Addr      Elf_Addr;


typedef Elf32_Ehdr      Elf_Ehdr;
typedef Elf32_Shdr      Elf_Shdr;
typedef Elf32_Phdr      Elf_Phdr;
typedef Elf32_Sym       Elf_Sym;

#if !defined(_ALLBSD_SOURCE) || defined(__APPLE__)
#define ELF_ST_TYPE ELF32_ST_TYPE
#endif
#endif

#include "globalDefinitions.hpp"
#include "memory/allocation.hpp"
#include "utilities/decoder.hpp"


class ElfStringTable;
class ElfSymbolTable;


// On Solaris/Linux platforms, libjvm.so does contain all private symbols.
// ElfFile is basically an elf file parser, which can lookup the symbol
// that is the nearest to the given address.
// Beware, this code is called from vm error reporting code, when vm is already
// in "error" state, so there are scenarios, lookup will fail. We want this
// part of code to be very defensive, and bait out if anything went wrong.

class ElfFile: public CHeapObj<mtInternal> {
  friend class ElfDecoder;
 public:
  ElfFile(const char* filepath);
  ~ElfFile();

  bool decode(address addr, char* buf, int buflen, int* offset);
  const char* filepath() {
    return m_filepath;
  }

  bool same_elf_file(const char* filepath) {
    assert(filepath, "null file path");
    assert(m_filepath, "already out of memory");
    return (m_filepath && !strcmp(filepath, m_filepath));
  }

  NullDecoder::decoder_status get_status() {
    return m_status;
  }

 private:
  // sanity check, if the file is a real elf file
  bool is_elf_file(Elf_Ehdr&);

  // load string tables from the elf file
  bool load_tables();

  // string tables are stored in a linked list
  void add_string_table(ElfStringTable* table);

  // symbol tables are stored in a linked list
  void add_symbol_table(ElfSymbolTable* table);

  // return a string table at specified section index
  ElfStringTable* get_string_table(int index);

protected:
   ElfFile*  next() const { return m_next; }
   void set_next(ElfFile* file) { m_next = file; }

 public:
  // Returns true if the elf file is marked NOT to require an executable stack,
  // or if the file could not be opened.
  // Returns false if the elf file requires an executable stack, the stack flag
  // is not set at all, or if the file can not be read.
  // On systems other than linux it always returns false.
  bool specifies_noexecstack() NOT_LINUX({ return false; });

 protected:
    ElfFile*         m_next;

 private:
  // file
  const char* m_filepath;
  FILE* m_file;

  // Elf header
  Elf_Ehdr                     m_elfHdr;

  // symbol tables
  ElfSymbolTable*              m_symbol_tables;

  // string tables
  ElfStringTable*              m_string_tables;

  NullDecoder::decoder_status  m_status;
};

#endif // _WINDOWS

#endif // SHARE_VM_UTILITIES_ELF_FILE_HPP

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