// 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.