// nacl.h -- Native Client support for gold    -*- C++ -*-

// Copyright (C) 2012-2024 Free Software Foundation, Inc.

// 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 "elfcpp_file.h"
#include "fileread.h"
#include "layout.h"
#include "target-select.h"
#include "target.h"

#ifndef GOLD_NACL_H
#define GOLD_NACL_H

namespace gold
{

class Sniff_file
{
public:
 Sniff_file(Input_file* input_file, off_t offset)
   : file_(input_file->file()), offset_(offset)
 { }

 class Location
 {
  public:
   Location(off_t file_offset, off_t data_size)
     : offset_(file_offset), size_(data_size)
   { }

   inline off_t offset() const
   { return this->offset_; }

   inline section_size_type size() const
   { return this->size_; }

  private:
   off_t offset_;
   section_size_type size_;
 };

 class View
 {
  public:
   View(File_read& file, off_t file_offset, off_t data_size)
     : data_(file.get_view(file_offset, 0, data_size, true, false))
   { }

   const unsigned char* data()
   { return this->data_; }

  private:
   const unsigned char* data_;
 };

 View view(off_t file_offset, off_t data_size)
 {
   return View(this->file_, this->offset_ + file_offset, data_size);
 }

 View view(Location loc)
 {
   return this->view(loc.offset(), loc.size());
 }

 // Report an error.
 void
 error(const char* format, ...) const ATTRIBUTE_PRINTF_2;

private:
 File_read& file_;
 off_t offset_;
};


template<class base_selector, class nacl_target>
class Target_selector_nacl : public base_selector
{
public:
 Target_selector_nacl(const char* nacl_abi_name,
                      const char* bfd_name, const char* emulation)
   : base_selector(), is_nacl_(false), nacl_abi_name_(nacl_abi_name),
     bfd_name_(bfd_name), emulation_(emulation)
 { }

protected:
 virtual Target*
 do_instantiate_target()
 {
   if (this->is_nacl_)
     return new nacl_target();
   return this->base_selector::do_instantiate_target();
 }

 virtual Target*
 do_recognize(Input_file* file, off_t offset,
              int machine, int osabi, int abiversion)
 {
   this->is_nacl_ = file != NULL && this->recognize_nacl_file(file, offset);
   if (this->is_nacl_)
     return this->instantiate_target();
   return this->base_selector::do_recognize(file, offset,
                                            machine, osabi, abiversion);
 }

 virtual Target*
 do_recognize_by_bfd_name(const char* name)
 {
   gold_assert(this->bfd_name_ != NULL);
   this->is_nacl_ = strcmp(name, this->bfd_name_) == 0;
   if (this->is_nacl_)
     return this->instantiate_target();
   return this->base_selector::do_recognize_by_bfd_name(name);
 }

 virtual void
 do_supported_bfd_names(std::vector<const char*>* names)
 {
   gold_assert(this->bfd_name_ != NULL);
   this->base_selector::do_supported_bfd_names(names);
   names->push_back(this->bfd_name_);
 }

 virtual void
 do_supported_emulations(std::vector<const char*>* emulations)
 {
   gold_assert(this->emulation_ != NULL);
   this->base_selector::do_supported_emulations(emulations);
   emulations->push_back(this->emulation_);
 }

 virtual const char*
 do_target_bfd_name(const Target* target)
 {
   return (!this->is_our_target(target)
           ? NULL
           : (this->is_nacl_
              ? this->bfd_name_
              : base_selector::do_target_bfd_name(target)));
 }

private:
 bool
 recognize_nacl_file(Input_file* input_file, off_t offset)
 {
   if (this->is_big_endian())
     {
#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
# ifdef HAVE_TARGET_32_BIG
       if (this->get_size() == 32)
         return do_recognize_nacl_file<32, true>(input_file, offset);
# endif
# ifdef HAVE_TARGET_64_BIG
       if (this->get_size() == 64)
         return do_recognize_nacl_file<64, true>(input_file, offset);
# endif
#endif
       gold_unreachable();
     }
   else
     {
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
# ifdef HAVE_TARGET_32_LITTLE
       if (this->get_size() == 32)
         return do_recognize_nacl_file<32, false>(input_file, offset);
# endif
# ifdef HAVE_TARGET_64_LITTLE
       if (this->get_size() == 64)
         return do_recognize_nacl_file<64, false>(input_file, offset);
# endif
#endif
       gold_unreachable();
     }
 }

 template<int size, bool big_endian>
 bool
 do_recognize_nacl_file(Input_file* input_file, off_t offset)
 {
   Sniff_file file(input_file, offset);
   elfcpp::Elf_file<size, big_endian, Sniff_file> elf_file(&file);
   const unsigned int shnum = elf_file.shnum();
   for (unsigned int shndx = 1; shndx < shnum; ++shndx)
     {
       if (elf_file.section_type(shndx) == elfcpp::SHT_NOTE)
         {
           Sniff_file::Location loc = elf_file.section_contents(shndx);
           if (loc.size() < (3 * 4
                             + align_address(sizeof "NaCl", 4)
                             + align_address(nacl_abi_name_.size() + 1, 4)))
             continue;
           Sniff_file::View view(file.view(loc));
           const unsigned char* note_data = view.data();
           if ((elfcpp::Swap<32, big_endian>::readval(note_data + 0)
                == sizeof "NaCl")
               && (elfcpp::Swap<32, big_endian>::readval(note_data + 4)
                   == nacl_abi_name_.size() + 1)
               && (elfcpp::Swap<32, big_endian>::readval(note_data + 8)
                   == elfcpp::NT_VERSION))
             {
               const unsigned char* name = note_data + 12;
               const unsigned char* desc = (name
                                            + align_address(sizeof "NaCl", 4));
               if (memcmp(name, "NaCl", sizeof "NaCl") == 0
                   && memcmp(desc, nacl_abi_name_.c_str(),
                             nacl_abi_name_.size() + 1) == 0)
                 return true;
             }
         }
     }
   return false;
 }

 // Whether we decided this was the NaCl target variant.
 bool is_nacl_;
 // The string found in the NaCl ABI note.
 std::string nacl_abi_name_;
 // BFD name of NaCl target, for compatibility.
 const char* const bfd_name_;
 // GNU linker emulation for this NaCl target, for compatibility.
 const char* const emulation_;
};

} // end namespace gold

#endif // !defined(GOLD_NACL_H)

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