| 1 | // binary.cc -- binary input files for gold |
| 2 | |
| 3 | // Copyright (C) 2008-2016 Free Software Foundation, Inc. |
| 4 | // Written by Ian Lance Taylor <iant@google.com>. |
| 5 | |
| 6 | // This file is part of gold. |
| 7 | |
| 8 | // This program is free software; you can redistribute it and/or modify |
| 9 | // it under the terms of the GNU General Public License as published by |
| 10 | // the Free Software Foundation; either version 3 of the License, or |
| 11 | // (at your option) any later version. |
| 12 | |
| 13 | // This program is distributed in the hope that it will be useful, |
| 14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | // GNU General Public License for more details. |
| 17 | |
| 18 | // You should have received a copy of the GNU General Public License |
| 19 | // along with this program; if not, write to the Free Software |
| 20 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| 21 | // MA 02110-1301, USA. |
| 22 | |
| 23 | #include "gold.h" |
| 24 | |
| 25 | #include <cerrno> |
| 26 | #include <cstring> |
| 27 | |
| 28 | #include "elfcpp.h" |
| 29 | #include "stringpool.h" |
| 30 | #include "fileread.h" |
| 31 | #include "output.h" |
| 32 | #include "binary.h" |
| 33 | |
| 34 | // safe-ctype.h interferes with macros defined by the system <ctype.h>. |
| 35 | // Some C++ system headers might include <ctype.h> and rely on its macro |
| 36 | // definitions being intact. So make sure that safe-ctype.h is included |
| 37 | // only after any C++ system headers, whether directly here (above) or via |
| 38 | // other local header files (e.g. #include <string> in "binary.h"). |
| 39 | #include "safe-ctype.h" |
| 40 | |
| 41 | // Support for reading binary files as input. These become blobs in |
| 42 | // the final output. These files are treated as though they have a |
| 43 | // single .data section and define three symbols: |
| 44 | // _binary_FILENAME_start, _binary_FILENAME_end, _binary_FILENAME_size. |
| 45 | // The FILENAME is the name of the input file, with any |
| 46 | // non-alphanumeric character changed to an underscore. |
| 47 | |
| 48 | // We implement this by creating an ELF file in memory. |
| 49 | |
| 50 | namespace gold |
| 51 | { |
| 52 | |
| 53 | // class Binary_to_elf. |
| 54 | |
| 55 | Binary_to_elf::Binary_to_elf(elfcpp::EM machine, int size, bool big_endian, |
| 56 | const std::string& filename) |
| 57 | : elf_machine_(machine), size_(size), big_endian_(big_endian), |
| 58 | filename_(filename), data_(NULL), filesize_(0) |
| 59 | { |
| 60 | } |
| 61 | |
| 62 | Binary_to_elf::~Binary_to_elf() |
| 63 | { |
| 64 | if (this->data_ != NULL) |
| 65 | delete[] this->data_; |
| 66 | } |
| 67 | |
| 68 | // Given FILENAME, create a buffer which looks like an ELF file with |
| 69 | // the contents of FILENAME as the contents of the only section. The |
| 70 | // TASK parameters is mainly for debugging, and records who holds |
| 71 | // locks. |
| 72 | |
| 73 | bool |
| 74 | Binary_to_elf::convert(const Task* task) |
| 75 | { |
| 76 | if (this->size_ == 32) |
| 77 | { |
| 78 | if (!this->big_endian_) |
| 79 | { |
| 80 | #ifdef HAVE_TARGET_32_LITTLE |
| 81 | return this->sized_convert<32, false>(task); |
| 82 | #else |
| 83 | gold_unreachable(); |
| 84 | #endif |
| 85 | } |
| 86 | else |
| 87 | { |
| 88 | #ifdef HAVE_TARGET_32_BIG |
| 89 | return this->sized_convert<32, true>(task); |
| 90 | #else |
| 91 | gold_unreachable(); |
| 92 | #endif |
| 93 | } |
| 94 | } |
| 95 | else if (this->size_ == 64) |
| 96 | { |
| 97 | if (!this->big_endian_) |
| 98 | { |
| 99 | #ifdef HAVE_TARGET_64_LITTLE |
| 100 | return this->sized_convert<64, false>(task); |
| 101 | #else |
| 102 | gold_unreachable(); |
| 103 | #endif |
| 104 | } |
| 105 | else |
| 106 | { |
| 107 | #ifdef HAVE_TARGET_64_BIG |
| 108 | return this->sized_convert<64, true>(task); |
| 109 | #else |
| 110 | gold_unreachable(); |
| 111 | #endif |
| 112 | } |
| 113 | } |
| 114 | else |
| 115 | gold_unreachable(); |
| 116 | } |
| 117 | |
| 118 | // We are going to create: |
| 119 | // * The ELF file header. |
| 120 | // * Five sections: null section, .data, .symtab, .strtab, .shstrtab |
| 121 | // * The contents of the file. |
| 122 | // * Four symbols: null, begin, end, size. |
| 123 | // * Three symbol names. |
| 124 | // * Four section names. |
| 125 | |
| 126 | template<int size, bool big_endian> |
| 127 | bool |
| 128 | Binary_to_elf::sized_convert(const Task* task) |
| 129 | { |
| 130 | // Read the input file. |
| 131 | |
| 132 | File_read f; |
| 133 | if (!f.open(task, this->filename_)) |
| 134 | { |
| 135 | gold_error(_("cannot open %s: %s:"), this->filename_.c_str(), |
| 136 | strerror(errno)); |
| 137 | return false; |
| 138 | } |
| 139 | |
| 140 | section_size_type filesize = convert_to_section_size_type(f.filesize()); |
| 141 | const unsigned char* fileview; |
| 142 | if (filesize == 0) |
| 143 | fileview = NULL; |
| 144 | else |
| 145 | fileview = f.get_view(0, 0, filesize, false, false); |
| 146 | |
| 147 | unsigned int align; |
| 148 | if (size == 32) |
| 149 | align = 4; |
| 150 | else if (size == 64) |
| 151 | align = 8; |
| 152 | else |
| 153 | gold_unreachable(); |
| 154 | section_size_type aligned_filesize = align_address(filesize, align); |
| 155 | |
| 156 | // Build the stringpool for the symbol table. |
| 157 | |
| 158 | std::string mangled_name = this->filename_; |
| 159 | for (std::string::iterator p = mangled_name.begin(); |
| 160 | p != mangled_name.end(); |
| 161 | ++p) |
| 162 | if (!ISALNUM(*p)) |
| 163 | *p = '_'; |
| 164 | mangled_name = "_binary_" + mangled_name; |
| 165 | std::string start_symbol_name = mangled_name + "_start"; |
| 166 | std::string end_symbol_name = mangled_name + "_end"; |
| 167 | std::string size_symbol_name = mangled_name + "_size"; |
| 168 | |
| 169 | Stringpool strtab; |
| 170 | strtab.add(start_symbol_name.c_str(), false, NULL); |
| 171 | strtab.add(end_symbol_name.c_str(), false, NULL); |
| 172 | strtab.add(size_symbol_name.c_str(), false, NULL); |
| 173 | strtab.set_string_offsets(); |
| 174 | |
| 175 | // Build the stringpool for the section name table. |
| 176 | |
| 177 | Stringpool shstrtab; |
| 178 | shstrtab.add(".data", false, NULL); |
| 179 | shstrtab.add(".symtab", false, NULL); |
| 180 | shstrtab.add(".strtab", false, NULL); |
| 181 | shstrtab.add(".shstrtab", false, NULL); |
| 182 | shstrtab.set_string_offsets(); |
| 183 | |
| 184 | // Work out the size of the generated file, and the offsets of the |
| 185 | // various sections, and allocate a buffer. |
| 186 | |
| 187 | const int sym_size = elfcpp::Elf_sizes<size>::sym_size; |
| 188 | |
| 189 | size_t output_size = (elfcpp::Elf_sizes<size>::ehdr_size |
| 190 | + 5 * elfcpp::Elf_sizes<size>::shdr_size); |
| 191 | size_t data_offset = output_size; |
| 192 | output_size += aligned_filesize; |
| 193 | size_t symtab_offset = output_size; |
| 194 | output_size += 4 * sym_size; |
| 195 | size_t strtab_offset = output_size; |
| 196 | output_size += strtab.get_strtab_size(); |
| 197 | size_t shstrtab_offset = output_size; |
| 198 | output_size += shstrtab.get_strtab_size(); |
| 199 | |
| 200 | unsigned char* buffer = new unsigned char[output_size]; |
| 201 | |
| 202 | // Write out the data. |
| 203 | |
| 204 | unsigned char* pout = buffer; |
| 205 | |
| 206 | this->write_file_header<size, big_endian>(&pout); |
| 207 | |
| 208 | this->write_section_header<size, big_endian>("", &shstrtab, elfcpp::SHT_NULL, |
| 209 | 0, 0, 0, 0, 0, |
| 210 | 0, 0, &pout); |
| 211 | // Having the section be named ".data", having it be writable, and |
| 212 | // giving it an alignment of 1 is because the GNU linker does it |
| 213 | // that way, and existing linker script expect it. |
| 214 | this->write_section_header<size, big_endian>(".data", &shstrtab, |
| 215 | elfcpp::SHT_PROGBITS, |
| 216 | (elfcpp::SHF_ALLOC |
| 217 | | elfcpp::SHF_WRITE), |
| 218 | data_offset, |
| 219 | filesize, 0, 0, |
| 220 | 1, 0, &pout); |
| 221 | this->write_section_header<size, big_endian>(".symtab", &shstrtab, |
| 222 | elfcpp::SHT_SYMTAB, |
| 223 | 0, symtab_offset, 4 * sym_size, |
| 224 | 3, 1, align, sym_size, &pout); |
| 225 | this->write_section_header<size, big_endian>(".strtab", &shstrtab, |
| 226 | elfcpp::SHT_STRTAB, |
| 227 | 0, strtab_offset, |
| 228 | strtab.get_strtab_size(), |
| 229 | 0, 0, 1, 0, &pout); |
| 230 | this->write_section_header<size, big_endian>(".shstrtab", &shstrtab, |
| 231 | elfcpp::SHT_STRTAB, |
| 232 | 0, shstrtab_offset, |
| 233 | shstrtab.get_strtab_size(), |
| 234 | 0, 0, 1, 0, &pout); |
| 235 | |
| 236 | if (filesize > 0) |
| 237 | { |
| 238 | memcpy(pout, fileview, filesize); |
| 239 | pout += filesize; |
| 240 | memset(pout, 0, aligned_filesize - filesize); |
| 241 | pout += aligned_filesize - filesize; |
| 242 | } |
| 243 | |
| 244 | this->write_symbol<size, big_endian>("", &strtab, 0, 0, 0, &pout); |
| 245 | this->write_symbol<size, big_endian>(start_symbol_name, &strtab, 0, filesize, |
| 246 | 1, &pout); |
| 247 | this->write_symbol<size, big_endian>(end_symbol_name, &strtab, filesize, 0, |
| 248 | 1, &pout); |
| 249 | this->write_symbol<size, big_endian>(size_symbol_name, &strtab, filesize, 0, |
| 250 | elfcpp::SHN_ABS, &pout); |
| 251 | |
| 252 | strtab.write_to_buffer(pout, strtab.get_strtab_size()); |
| 253 | pout += strtab.get_strtab_size(); |
| 254 | |
| 255 | shstrtab.write_to_buffer(pout, shstrtab.get_strtab_size()); |
| 256 | pout += shstrtab.get_strtab_size(); |
| 257 | |
| 258 | gold_assert(static_cast<size_t>(pout - buffer) == output_size); |
| 259 | |
| 260 | this->data_ = buffer; |
| 261 | this->filesize_ = output_size; |
| 262 | |
| 263 | f.unlock(task); |
| 264 | |
| 265 | return true; |
| 266 | } |
| 267 | |
| 268 | // Write out the file header. |
| 269 | |
| 270 | template<int size, bool big_endian> |
| 271 | void |
| 272 | Binary_to_elf::write_file_header(unsigned char** ppout) |
| 273 | { |
| 274 | elfcpp::Ehdr_write<size, big_endian> oehdr(*ppout); |
| 275 | |
| 276 | unsigned char e_ident[elfcpp::EI_NIDENT]; |
| 277 | memset(e_ident, 0, elfcpp::EI_NIDENT); |
| 278 | e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0; |
| 279 | e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1; |
| 280 | e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2; |
| 281 | e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3; |
| 282 | if (size == 32) |
| 283 | e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32; |
| 284 | else if (size == 64) |
| 285 | e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64; |
| 286 | else |
| 287 | gold_unreachable(); |
| 288 | e_ident[elfcpp::EI_DATA] = (big_endian |
| 289 | ? elfcpp::ELFDATA2MSB |
| 290 | : elfcpp::ELFDATA2LSB); |
| 291 | e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT; |
| 292 | oehdr.put_e_ident(e_ident); |
| 293 | |
| 294 | oehdr.put_e_type(elfcpp::ET_REL); |
| 295 | oehdr.put_e_machine(this->elf_machine_); |
| 296 | oehdr.put_e_version(elfcpp::EV_CURRENT); |
| 297 | oehdr.put_e_entry(0); |
| 298 | oehdr.put_e_phoff(0); |
| 299 | oehdr.put_e_shoff(elfcpp::Elf_sizes<size>::ehdr_size); |
| 300 | oehdr.put_e_flags(0); |
| 301 | oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size); |
| 302 | oehdr.put_e_phentsize(0); |
| 303 | oehdr.put_e_phnum(0); |
| 304 | oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size); |
| 305 | oehdr.put_e_shnum(5); |
| 306 | oehdr.put_e_shstrndx(4); |
| 307 | |
| 308 | *ppout += elfcpp::Elf_sizes<size>::ehdr_size; |
| 309 | } |
| 310 | |
| 311 | // Write out a section header. |
| 312 | |
| 313 | template<int size, bool big_endian> |
| 314 | void |
| 315 | Binary_to_elf::write_section_header( |
| 316 | const char* name, |
| 317 | const Stringpool* shstrtab, |
| 318 | elfcpp::SHT type, |
| 319 | unsigned int flags, |
| 320 | section_size_type offset, |
| 321 | section_size_type section_size, |
| 322 | unsigned int link, |
| 323 | unsigned int info, |
| 324 | unsigned int addralign, |
| 325 | unsigned int entsize, |
| 326 | unsigned char** ppout) |
| 327 | { |
| 328 | elfcpp::Shdr_write<size, big_endian> oshdr(*ppout); |
| 329 | |
| 330 | oshdr.put_sh_name(*name == '\0' ? 0 : shstrtab->get_offset(name)); |
| 331 | oshdr.put_sh_type(type); |
| 332 | oshdr.put_sh_flags(flags); |
| 333 | oshdr.put_sh_addr(0); |
| 334 | oshdr.put_sh_offset(offset); |
| 335 | oshdr.put_sh_size(section_size); |
| 336 | oshdr.put_sh_link(link); |
| 337 | oshdr.put_sh_info(info); |
| 338 | oshdr.put_sh_addralign(addralign); |
| 339 | oshdr.put_sh_entsize(entsize); |
| 340 | |
| 341 | *ppout += elfcpp::Elf_sizes<size>::shdr_size; |
| 342 | } |
| 343 | |
| 344 | // Write out a symbol. |
| 345 | |
| 346 | template<int size, bool big_endian> |
| 347 | void |
| 348 | Binary_to_elf::write_symbol( |
| 349 | const std::string& name, |
| 350 | const Stringpool* strtab, |
| 351 | section_size_type value, |
| 352 | typename elfcpp::Elf_types<32>::Elf_WXword st_size, |
| 353 | unsigned int shndx, |
| 354 | unsigned char** ppout) |
| 355 | { |
| 356 | unsigned char* pout = *ppout; |
| 357 | |
| 358 | elfcpp::Sym_write<size, big_endian> osym(pout); |
| 359 | osym.put_st_name(name.empty() ? 0 : strtab->get_offset(name.c_str())); |
| 360 | osym.put_st_value(value); |
| 361 | osym.put_st_size(st_size); |
| 362 | osym.put_st_info(name.empty() ? elfcpp::STB_LOCAL : elfcpp::STB_GLOBAL, |
| 363 | elfcpp::STT_NOTYPE); |
| 364 | osym.put_st_other(elfcpp::STV_DEFAULT, 0); |
| 365 | osym.put_st_shndx(shndx); |
| 366 | |
| 367 | *ppout += elfcpp::Elf_sizes<size>::sym_size; |
| 368 | } |
| 369 | |
| 370 | } // End namespace gold. |