/*

 * 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.

 *

 */

#include "precompiled.hpp"

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

#include "memory/allocation.inline.hpp"

#include "utilities/elfFuncDescTable.hpp"

#include "utilities/elfSymbolTable.hpp"

ElfSymbolTable::ElfSymbolTable(FILE* file, Elf_Shdr shdr) {

  assert(file, "null file handle");

  m_symbols = NULL;

  m_next = NULL;

  m_file = file;

  m_status = NullDecoder::no_error;

  // try to load the string table

  long cur_offset = ftell(file);

  if (cur_offset != -1) {

    // call malloc so we can back up if memory allocation fails.

    m_symbols = (Elf_Sym*)os::malloc(shdr.sh_size, mtInternal);

    if (m_symbols) {

      if (fseek(file, shdr.sh_offset, SEEK_SET) ||

        fread((void*)m_symbols, shdr.sh_size, 1, file) != 1 ||

        fseek(file, cur_offset, SEEK_SET)) {

        m_status = NullDecoder::file_invalid;

        os::free(m_symbols);

        m_symbols = NULL;

      }

    }

    if (!NullDecoder::is_error(m_status)) {

      memcpy(&m_shdr, &shdr, sizeof(Elf_Shdr));

    }

  } else {

    m_status = NullDecoder::file_invalid;

  }

}

ElfSymbolTable::~ElfSymbolTable() {

  if (m_symbols != NULL) {

    os::free(m_symbols);

  }

  if (m_next != NULL) {

    delete m_next;

  }

}

bool ElfSymbolTable::compare(const Elf_Sym* sym, address addr, int* stringtableIndex, int* posIndex, int* offset, ElfFuncDescTable* funcDescTable) {

  if (STT_FUNC == ELF_ST_TYPE(sym->st_info)) {

    Elf_Word st_size = sym->st_size;

    address sym_addr;

    if (funcDescTable != NULL && funcDescTable->get_index() == sym->st_shndx) {

      // We need to go another step trough the function descriptor table (currently PPC64 only)

      sym_addr = funcDescTable->lookup(sym->st_value);

    } else {

      sym_addr = (address)sym->st_value;

    }

    if (sym_addr <= addr && (Elf_Word)(addr - sym_addr) < st_size) {

      *offset = (int)(addr - sym_addr);

      *posIndex = sym->st_name;

      *stringtableIndex = m_shdr.sh_link;

      return true;

    }

  }

  return false;

}

bool ElfSymbolTable::lookup(address addr, int* stringtableIndex, int* posIndex, int* offset, ElfFuncDescTable* funcDescTable) {

  assert(stringtableIndex, "null string table index pointer");

  assert(posIndex, "null string table offset pointer");

  assert(offset, "null offset pointer");

  if (NullDecoder::is_error(m_status)) {

    return false;

  }

  size_t  sym_size = sizeof(Elf_Sym);

  assert((m_shdr.sh_size % sym_size) == 0, "check size");

  int count = m_shdr.sh_size / sym_size;

  if (m_symbols != NULL) {

    for (int index = 0; index < count; index ++) {

      if (compare(&m_symbols[index], addr, stringtableIndex, posIndex, offset, funcDescTable)) {

        return true;

      }

    }

  } else {

    long cur_pos;

    if ((cur_pos = ftell(m_file)) == -1 ||

      fseek(m_file, m_shdr.sh_offset, SEEK_SET)) {

      m_status = NullDecoder::file_invalid;

      return false;

    }

    Elf_Sym sym;

    for (int index = 0; index < count; index ++) {

      if (fread(&sym, sym_size, 1, m_file) == 1) {

        if (compare(&sym, addr, stringtableIndex, posIndex, offset, funcDescTable)) {

          return true;

        }

      } else {

        m_status = NullDecoder::file_invalid;

        return false;

      }

    }

    fseek(m_file, cur_pos, SEEK_SET);

  }

  return false;

}

#endif // !_WINDOWS && !__APPLE__