Subversion Repositories open8_urisc

// binary.cc -- binary input files for gold

// Copyright 2008 Free Software Foundation, Inc.

// Written by Ian Lance Taylor <iant@google.com>.

// This file is part of gold.

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

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation; either version 3 of the License, or

// (at your option) any later version.

// This program 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 for more details.

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

// along with this program; if not, write to the Free Software

// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,

// MA 02110-1301, USA.

#include "gold.h"

#include <cerrno>

#include <cstring>

#include "safe-ctype.h"

#include "elfcpp.h"

#include "stringpool.h"

#include "fileread.h"

#include "output.h"

#include "binary.h"

// Support for reading binary files as input.  These become blobs in

// the final output.  These files are treated as though they have a

// single .data section and define three symbols:

// _binary_FILENAME_start, _binary_FILENAME_end, _binary_FILENAME_size.

// The FILENAME is the name of the input file, with any

// non-alphanumeric character changed to an underscore.

// We implement this by creating an ELF file in memory.

namespace gold

{

// class Binary_to_elf.

Binary_to_elf::Binary_to_elf(elfcpp::EM machine, int size, bool big_endian,

                             const std::string& filename)

  : elf_machine_(machine), size_(size), big_endian_(big_endian),

    filename_(filename), data_(NULL), filesize_(0)

{

}

Binary_to_elf::~Binary_to_elf()

{

  if (this->data_ != NULL)

    delete[] this->data_;

}

// Given FILENAME, create a buffer which looks like an ELF file with

// the contents of FILENAME as the contents of the only section.  The

// TASK parameters is mainly for debugging, and records who holds

// locks.

bool

Binary_to_elf::convert(const Task* task)

{

  if (this->size_ == 32)

    {

      if (!this->big_endian_)

        {

#ifdef HAVE_TARGET_32_LITTLE

          return this->sized_convert<32, false>(task);

#else

          gold_unreachable();

#endif

        }

      else

        {

#ifdef HAVE_TARGET_32_BIG

          return this->sized_convert<32, true>(task);

#else

          gold_unreachable();

#endif

        }

    }

  else if (this->size_ == 64)

    {

      if (!this->big_endian_)

        {

#ifdef HAVE_TARGET_64_LITTLE

          return this->sized_convert<64, false>(task);

#else

          gold_unreachable();

#endif

        }

      else

        {

#ifdef HAVE_TARGET_64_BIG

          return this->sized_convert<64, true>(task);

#else

          gold_unreachable();

#endif

        }

    }

  else

    gold_unreachable();

}

// We are going to create:

// * The ELF file header.

// * Five sections: null section, .data, .symtab, .strtab, .shstrtab

// * The contents of the file.

// * Four symbols: null, begin, end, size.

// * Three symbol names.

// * Four section names.

template<int size, bool big_endian>

bool

Binary_to_elf::sized_convert(const Task* task)

{

  // Read the input file.

  File_read f;

  if (!f.open(task, this->filename_))

    {

      gold_error(_("cannot open %s: %s:"), this->filename_.c_str(),

                 strerror(errno));

      return false;

    }

  section_size_type filesize = convert_to_section_size_type(f.filesize());

  const unsigned char* fileview;

  if (filesize == 0)

    fileview = NULL;

  else

    fileview = f.get_view(0, 0, filesize, false, false);

  unsigned int align;

  if (size == 32)

    align = 4;

  else if (size == 64)

    align = 8;

  else

    gold_unreachable();

  section_size_type aligned_filesize = align_address(filesize, align);

  // Build the stringpool for the symbol table.

  std::string mangled_name = this->filename_;

  for (std::string::iterator p = mangled_name.begin();

       p != mangled_name.end();

       ++p)

    if (!ISALNUM(*p))

      *p = '_';

  mangled_name = "_binary_" + mangled_name;

  std::string start_symbol_name = mangled_name + "_start";

  std::string end_symbol_name = mangled_name + "_end";

  std::string size_symbol_name = mangled_name + "_size";

  Stringpool strtab;

  strtab.add(start_symbol_name.c_str(), false, NULL);

  strtab.add(end_symbol_name.c_str(), false, NULL);

  strtab.add(size_symbol_name.c_str(), false, NULL);

  strtab.set_string_offsets();

  // Build the stringpool for the section name table.

  Stringpool shstrtab;

  shstrtab.add(".data", false, NULL);

  shstrtab.add(".symtab", false, NULL);

  shstrtab.add(".strtab", false, NULL);

  shstrtab.add(".shstrtab", false, NULL);

  shstrtab.set_string_offsets();

  // Work out the size of the generated file, and the offsets of the

  // various sections, and allocate a buffer.

  const int sym_size = elfcpp::Elf_sizes<size>::sym_size;

  size_t output_size = (elfcpp::Elf_sizes<size>::ehdr_size

                        + 5 * elfcpp::Elf_sizes<size>::shdr_size);

  size_t data_offset = output_size;

  output_size += aligned_filesize;

  size_t symtab_offset = output_size;

  output_size += 4 * sym_size;

  size_t strtab_offset = output_size;

  output_size += strtab.get_strtab_size();

  size_t shstrtab_offset = output_size;

  output_size += shstrtab.get_strtab_size();

  unsigned char* buffer = new unsigned char[output_size];

  // Write out the data.

  unsigned char* pout = buffer;

  this->write_file_header<size, big_endian>(&pout);

  this->write_section_header<size, big_endian>("", &shstrtab, elfcpp::SHT_NULL,

                                               0, 0, 0, 0, 0,

                                               0, 0, &pout);

  // Having the section be named ".data", having it be writable, and

  // giving it an alignment of 1 is because the GNU linker does it

  // that way, and existing linker script expect it.

  this->write_section_header<size, big_endian>(".data", &shstrtab,

                                               elfcpp::SHT_PROGBITS,

                                               (elfcpp::SHF_ALLOC

                                                | elfcpp::SHF_WRITE),

                                               data_offset,

                                               filesize, 0, 0,

                                               1, 0, &pout);

  this->write_section_header<size, big_endian>(".symtab", &shstrtab,

                                               elfcpp::SHT_SYMTAB,

                                               0, symtab_offset, 4 * sym_size,

                                               3, 1, align, sym_size, &pout);

  this->write_section_header<size, big_endian>(".strtab", &shstrtab,

                                               elfcpp::SHT_STRTAB,

                                               0, strtab_offset,

                                               strtab.get_strtab_size(),

                                               0, 0, 1, 0, &pout);

  this->write_section_header<size, big_endian>(".shstrtab", &shstrtab,

                                               elfcpp::SHT_STRTAB,

                                               0, shstrtab_offset,

                                               shstrtab.get_strtab_size(),

                                               0, 0, 1, 0, &pout);

  if (filesize > 0)

    {

      memcpy(pout, fileview, filesize);

      pout += filesize;

      memset(pout, 0, aligned_filesize - filesize);

      pout += aligned_filesize - filesize;

    }

  this->write_symbol<size, big_endian>("", &strtab, 0, 0, &pout);

  this->write_symbol<size, big_endian>(start_symbol_name, &strtab, 0, 1,

                                       &pout);

  this->write_symbol<size, big_endian>(end_symbol_name, &strtab, filesize, 1,

                                       &pout);

  this->write_symbol<size, big_endian>(size_symbol_name, &strtab, filesize,

                                       elfcpp::SHN_ABS, &pout);

  strtab.write_to_buffer(pout, strtab.get_strtab_size());

  pout += strtab.get_strtab_size();

  shstrtab.write_to_buffer(pout, shstrtab.get_strtab_size());

  pout += shstrtab.get_strtab_size();

  gold_assert(static_cast<size_t>(pout - buffer) == output_size);

  this->data_ = buffer;

  this->filesize_ = output_size;

  f.unlock(task);

  return true;

}

// Write out the file header.

template<int size, bool big_endian>

void

Binary_to_elf::write_file_header(unsigned char** ppout)

{

  elfcpp::Ehdr_write<size, big_endian> oehdr(*ppout);

  unsigned char e_ident[elfcpp::EI_NIDENT];

  memset(e_ident, 0, elfcpp::EI_NIDENT);

  e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;

  e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;

  e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;

  e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;

  if (size == 32)

    e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;

  else if (size == 64)

    e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;

  else

    gold_unreachable();

  e_ident[elfcpp::EI_DATA] = (big_endian

                              ? elfcpp::ELFDATA2MSB

                              : elfcpp::ELFDATA2LSB);

  e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;

  oehdr.put_e_ident(e_ident);

  oehdr.put_e_type(elfcpp::ET_REL);

  oehdr.put_e_machine(this->elf_machine_);

  oehdr.put_e_version(elfcpp::EV_CURRENT);

  oehdr.put_e_entry(0);

  oehdr.put_e_phoff(0);

  oehdr.put_e_shoff(elfcpp::Elf_sizes<size>::ehdr_size);

  oehdr.put_e_flags(0);

  oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);

  oehdr.put_e_phentsize(0);

  oehdr.put_e_phnum(0);

  oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);

  oehdr.put_e_shnum(5);

  oehdr.put_e_shstrndx(4);

  *ppout += elfcpp::Elf_sizes<size>::ehdr_size;

}

// Write out a section header.

template<int size, bool big_endian>

void

Binary_to_elf::write_section_header(

    const char* name,

    const Stringpool* shstrtab,

    elfcpp::SHT type,

    unsigned int flags,

    section_size_type offset,

    section_size_type section_size,

    unsigned int link,

    unsigned int info,

    unsigned int addralign,

    unsigned int entsize,

    unsigned char** ppout)

{

  elfcpp::Shdr_write<size, big_endian> oshdr(*ppout);

  oshdr.put_sh_name(*name == '\0' ? 0 : shstrtab->get_offset(name));

  oshdr.put_sh_type(type);

  oshdr.put_sh_flags(flags);

  oshdr.put_sh_addr(0);

  oshdr.put_sh_offset(offset);

  oshdr.put_sh_size(section_size);

  oshdr.put_sh_link(link);

  oshdr.put_sh_info(info);

  oshdr.put_sh_addralign(addralign);

  oshdr.put_sh_entsize(entsize);

  *ppout += elfcpp::Elf_sizes<size>::shdr_size;

}

// Write out a symbol.

template<int size, bool big_endian>

void

Binary_to_elf::write_symbol(

    const std::string& name,

    const Stringpool* strtab,

    section_size_type value,

    unsigned int shndx,

    unsigned char** ppout)

{

  unsigned char* pout = *ppout;

  elfcpp::Sym_write<size, big_endian> osym(pout);

  osym.put_st_name(name.empty() ? 0 : strtab->get_offset(name.c_str()));

  osym.put_st_value(value);

  osym.put_st_size(0);

  osym.put_st_info(name.empty() ? elfcpp::STB_LOCAL : elfcpp::STB_GLOBAL,

                   elfcpp::STT_NOTYPE);

  osym.put_st_other(elfcpp::STV_DEFAULT, 0);

  osym.put_st_shndx(shndx);

  *ppout += elfcpp::Elf_sizes<size>::sym_size;

}

} // End namespace gold.