/*

 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.

 * Copyright 2012, 2013 SAP AG. 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"

ElfFuncDescTable::ElfFuncDescTable(FILE* file, Elf_Shdr shdr, int index) {

  assert(file, "null file handle");

  // The actual function address (i.e. function entry point) is always the

  // first value in the function descriptor (on IA64 and PPC64 they look as follows):

  // PPC64: [function entry point, TOC pointer, environment pointer]

  // IA64 : [function entry point, GP (global pointer) value]

  // Unfortunately 'shdr.sh_entsize' doesn't always seem to contain this size (it's zero on PPC64) so we can't assert

  // assert(IA64_ONLY(2) PPC64_ONLY(3) * sizeof(address) == shdr.sh_entsize, "Size mismatch for '.opd' section entries");

  m_funcDescs = NULL;

  m_file = file;

  m_index = index;

  m_status = NullDecoder::no_error;

  // try to load the function descriptor table

  long cur_offset = ftell(file);

  if (cur_offset != -1) {

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

    m_funcDescs = (address*)os::malloc(shdr.sh_size, mtInternal);

    if (m_funcDescs) {

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

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

          fseek(file, cur_offset, SEEK_SET)) {

        m_status = NullDecoder::file_invalid;

        os::free(m_funcDescs);

        m_funcDescs = NULL;

      }

    }

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

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

    }

  } else {

    m_status = NullDecoder::file_invalid;

  }

}

ElfFuncDescTable::~ElfFuncDescTable() {

  if (m_funcDescs != NULL) {

    os::free(m_funcDescs);

  }

}

address ElfFuncDescTable::lookup(Elf_Word index) {

  if (NullDecoder::is_error(m_status)) {

    return NULL;

  }

  if (m_funcDescs != NULL) {

    if (m_shdr.sh_size > 0 && m_shdr.sh_addr <= index && index <= m_shdr.sh_addr + m_shdr.sh_size) {

      // Notice that 'index' is a byte-offset into the function descriptor table.

      return m_funcDescs[(index - m_shdr.sh_addr) / sizeof(address)];

    }

    return NULL;

  } else {

    long cur_pos;

    address addr;

    if (!(m_shdr.sh_size > 0 && m_shdr.sh_addr <= index && index <= m_shdr.sh_addr + m_shdr.sh_size)) {

      // don't put the whole decoder in error mode if we just tried a wrong index

      return NULL;

    }

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

        fseek(m_file, m_shdr.sh_offset + index - m_shdr.sh_addr, SEEK_SET) ||

        fread(&addr, sizeof(addr), 1, m_file) != 1 ||

        fseek(m_file, cur_pos, SEEK_SET)) {

      m_status = NullDecoder::file_invalid;

      return NULL;

    }

    return addr;

  }

}

#endif // !_WINDOWS && !__APPLE__