1 //===- ELFObjectFile.cpp - ELF object file implementation -------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines the ELFObjectFile class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/ADT/SmallVector.h" 15 #include "llvm/ADT/StringSwitch.h" 16 #include "llvm/ADT/Triple.h" 17 #include "llvm/Object/ObjectFile.h" 18 #include "llvm/Support/ELF.h" 19 #include "llvm/Support/Endian.h" 20 #include "llvm/Support/ErrorHandling.h" 21 #include "llvm/Support/MemoryBuffer.h" 22 #include <limits> 23 #include <utility> 24 25 using namespace llvm; 26 using namespace object; 27 28 // Templates to choose Elf_Addr and Elf_Off depending on is64Bits. 29 namespace { 30 template<support::endianness target_endianness> 31 struct ELFDataTypeTypedefHelperCommon { 32 typedef support::detail::packed_endian_specific_integral 33 <uint16_t, target_endianness, support::aligned> Elf_Half; 34 typedef support::detail::packed_endian_specific_integral 35 <uint32_t, target_endianness, support::aligned> Elf_Word; 36 typedef support::detail::packed_endian_specific_integral 37 <int32_t, target_endianness, support::aligned> Elf_Sword; 38 typedef support::detail::packed_endian_specific_integral 39 <uint64_t, target_endianness, support::aligned> Elf_Xword; 40 typedef support::detail::packed_endian_specific_integral 41 <int64_t, target_endianness, support::aligned> Elf_Sxword; 42 }; 43 } 44 45 namespace { 46 template<support::endianness target_endianness, bool is64Bits> 47 struct ELFDataTypeTypedefHelper; 48 49 /// ELF 32bit types. 50 template<support::endianness target_endianness> 51 struct ELFDataTypeTypedefHelper<target_endianness, false> 52 : ELFDataTypeTypedefHelperCommon<target_endianness> { 53 typedef support::detail::packed_endian_specific_integral 54 <uint32_t, target_endianness, support::aligned> Elf_Addr; 55 typedef support::detail::packed_endian_specific_integral 56 <uint32_t, target_endianness, support::aligned> Elf_Off; 57 }; 58 59 /// ELF 64bit types. 60 template<support::endianness target_endianness> 61 struct ELFDataTypeTypedefHelper<target_endianness, true> 62 : ELFDataTypeTypedefHelperCommon<target_endianness>{ 63 typedef support::detail::packed_endian_specific_integral 64 <uint64_t, target_endianness, support::aligned> Elf_Addr; 65 typedef support::detail::packed_endian_specific_integral 66 <uint64_t, target_endianness, support::aligned> Elf_Off; 67 }; 68 } 69 70 // I really don't like doing this, but the alternative is copypasta. 71 #define LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits) \ 72 typedef typename \ 73 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Addr Elf_Addr; \ 74 typedef typename \ 75 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Off Elf_Off; \ 76 typedef typename \ 77 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Half Elf_Half; \ 78 typedef typename \ 79 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Word Elf_Word; \ 80 typedef typename \ 81 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Sword Elf_Sword; \ 82 typedef typename \ 83 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Xword Elf_Xword; \ 84 typedef typename \ 85 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Sxword Elf_Sxword; 86 87 // Section header. 88 namespace { 89 template<support::endianness target_endianness, bool is64Bits> 90 struct Elf_Shdr_Base; 91 92 template<support::endianness target_endianness> 93 struct Elf_Shdr_Base<target_endianness, false> { 94 LLVM_ELF_IMPORT_TYPES(target_endianness, false) 95 Elf_Word sh_name; // Section name (index into string table) 96 Elf_Word sh_type; // Section type (SHT_*) 97 Elf_Word sh_flags; // Section flags (SHF_*) 98 Elf_Addr sh_addr; // Address where section is to be loaded 99 Elf_Off sh_offset; // File offset of section data, in bytes 100 Elf_Word sh_size; // Size of section, in bytes 101 Elf_Word sh_link; // Section type-specific header table index link 102 Elf_Word sh_info; // Section type-specific extra information 103 Elf_Word sh_addralign;// Section address alignment 104 Elf_Word sh_entsize; // Size of records contained within the section 105 }; 106 107 template<support::endianness target_endianness> 108 struct Elf_Shdr_Base<target_endianness, true> { 109 LLVM_ELF_IMPORT_TYPES(target_endianness, true) 110 Elf_Word sh_name; // Section name (index into string table) 111 Elf_Word sh_type; // Section type (SHT_*) 112 Elf_Xword sh_flags; // Section flags (SHF_*) 113 Elf_Addr sh_addr; // Address where section is to be loaded 114 Elf_Off sh_offset; // File offset of section data, in bytes 115 Elf_Xword sh_size; // Size of section, in bytes 116 Elf_Word sh_link; // Section type-specific header table index link 117 Elf_Word sh_info; // Section type-specific extra information 118 Elf_Xword sh_addralign;// Section address alignment 119 Elf_Xword sh_entsize; // Size of records contained within the section 120 }; 121 122 template<support::endianness target_endianness, bool is64Bits> 123 struct Elf_Shdr_Impl : Elf_Shdr_Base<target_endianness, is64Bits> { 124 using Elf_Shdr_Base<target_endianness, is64Bits>::sh_entsize; 125 using Elf_Shdr_Base<target_endianness, is64Bits>::sh_size; 126 127 /// @brief Get the number of entities this section contains if it has any. 128 unsigned getEntityCount() const { 129 if (sh_entsize == 0) 130 return 0; 131 return sh_size / sh_entsize; 132 } 133 }; 134 } 135 136 namespace { 137 template<support::endianness target_endianness, bool is64Bits> 138 struct Elf_Sym_Base; 139 140 template<support::endianness target_endianness> 141 struct Elf_Sym_Base<target_endianness, false> { 142 LLVM_ELF_IMPORT_TYPES(target_endianness, false) 143 Elf_Word st_name; // Symbol name (index into string table) 144 Elf_Addr st_value; // Value or address associated with the symbol 145 Elf_Word st_size; // Size of the symbol 146 unsigned char st_info; // Symbol's type and binding attributes 147 unsigned char st_other; // Must be zero; reserved 148 Elf_Half st_shndx; // Which section (header table index) it's defined in 149 }; 150 151 template<support::endianness target_endianness> 152 struct Elf_Sym_Base<target_endianness, true> { 153 LLVM_ELF_IMPORT_TYPES(target_endianness, true) 154 Elf_Word st_name; // Symbol name (index into string table) 155 unsigned char st_info; // Symbol's type and binding attributes 156 unsigned char st_other; // Must be zero; reserved 157 Elf_Half st_shndx; // Which section (header table index) it's defined in 158 Elf_Addr st_value; // Value or address associated with the symbol 159 Elf_Xword st_size; // Size of the symbol 160 }; 161 162 template<support::endianness target_endianness, bool is64Bits> 163 struct Elf_Sym_Impl : Elf_Sym_Base<target_endianness, is64Bits> { 164 using Elf_Sym_Base<target_endianness, is64Bits>::st_info; 165 166 // These accessors and mutators correspond to the ELF32_ST_BIND, 167 // ELF32_ST_TYPE, and ELF32_ST_INFO macros defined in the ELF specification: 168 unsigned char getBinding() const { return st_info >> 4; } 169 unsigned char getType() const { return st_info & 0x0f; } 170 void setBinding(unsigned char b) { setBindingAndType(b, getType()); } 171 void setType(unsigned char t) { setBindingAndType(getBinding(), t); } 172 void setBindingAndType(unsigned char b, unsigned char t) { 173 st_info = (b << 4) + (t & 0x0f); 174 } 175 }; 176 } 177 178 namespace { 179 template<support::endianness target_endianness, bool is64Bits> 180 class ELFObjectFile : public ObjectFile { 181 LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits) 182 183 typedef Elf_Shdr_Impl<target_endianness, is64Bits> Elf_Shdr; 184 typedef Elf_Sym_Impl<target_endianness, is64Bits> Elf_Sym; 185 186 struct Elf_Ehdr { 187 unsigned char e_ident[ELF::EI_NIDENT]; // ELF Identification bytes 188 Elf_Half e_type; // Type of file (see ET_*) 189 Elf_Half e_machine; // Required architecture for this file (see EM_*) 190 Elf_Word e_version; // Must be equal to 1 191 Elf_Addr e_entry; // Address to jump to in order to start program 192 Elf_Off e_phoff; // Program header table's file offset, in bytes 193 Elf_Off e_shoff; // Section header table's file offset, in bytes 194 Elf_Word e_flags; // Processor-specific flags 195 Elf_Half e_ehsize; // Size of ELF header, in bytes 196 Elf_Half e_phentsize;// Size of an entry in the program header table 197 Elf_Half e_phnum; // Number of entries in the program header table 198 Elf_Half e_shentsize;// Size of an entry in the section header table 199 Elf_Half e_shnum; // Number of entries in the section header table 200 Elf_Half e_shstrndx; // Section header table index of section name 201 // string table 202 bool checkMagic() const { 203 return (memcmp(e_ident, ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0; 204 } 205 unsigned char getFileClass() const { return e_ident[ELF::EI_CLASS]; } 206 unsigned char getDataEncoding() const { return e_ident[ELF::EI_DATA]; } 207 }; 208 209 typedef SmallVector<const Elf_Shdr*, 1> SymbolTableSections_t; 210 211 const Elf_Ehdr *Header; 212 const Elf_Shdr *SectionHeaderTable; 213 const Elf_Shdr *dot_shstrtab_sec; // Section header string table. 214 const Elf_Shdr *dot_strtab_sec; // Symbol header string table. 215 SymbolTableSections_t SymbolTableSections; 216 217 void validateSymbol(DataRefImpl Symb) const; 218 const Elf_Sym *getSymbol(DataRefImpl Symb) const; 219 const Elf_Shdr *getSection(DataRefImpl index) const; 220 const Elf_Shdr *getSection(uint16_t index) const; 221 const char *getString(uint16_t section, uint32_t offset) const; 222 const char *getString(const Elf_Shdr *section, uint32_t offset) const; 223 224 protected: 225 virtual error_code getSymbolNext(DataRefImpl Symb, SymbolRef &Res) const; 226 virtual error_code getSymbolName(DataRefImpl Symb, StringRef &Res) const; 227 virtual error_code getSymbolAddress(DataRefImpl Symb, uint64_t &Res) const; 228 virtual error_code getSymbolSize(DataRefImpl Symb, uint64_t &Res) const; 229 virtual error_code getSymbolNMTypeChar(DataRefImpl Symb, char &Res) const; 230 virtual error_code isSymbolInternal(DataRefImpl Symb, bool &Res) const; 231 232 virtual error_code getSectionNext(DataRefImpl Sec, SectionRef &Res) const; 233 virtual error_code getSectionName(DataRefImpl Sec, StringRef &Res) const; 234 virtual error_code getSectionAddress(DataRefImpl Sec, uint64_t &Res) const; 235 virtual error_code getSectionSize(DataRefImpl Sec, uint64_t &Res) const; 236 virtual error_code getSectionContents(DataRefImpl Sec, StringRef &Res) const; 237 virtual error_code isSectionText(DataRefImpl Sec, bool &Res) const; 238 239 public: 240 ELFObjectFile(MemoryBuffer *Object, error_code &ec); 241 virtual symbol_iterator begin_symbols() const; 242 virtual symbol_iterator end_symbols() const; 243 virtual section_iterator begin_sections() const; 244 virtual section_iterator end_sections() const; 245 246 virtual uint8_t getBytesInAddress() const; 247 virtual StringRef getFileFormatName() const; 248 virtual unsigned getArch() const; 249 }; 250 } // end namespace 251 252 template<support::endianness target_endianness, bool is64Bits> 253 void ELFObjectFile<target_endianness, is64Bits> 254 ::validateSymbol(DataRefImpl Symb) const { 255 const Elf_Sym *symb = getSymbol(Symb); 256 const Elf_Shdr *SymbolTableSection = SymbolTableSections[Symb.d.b]; 257 // FIXME: We really need to do proper error handling in the case of an invalid 258 // input file. Because we don't use exceptions, I think we'll just pass 259 // an error object around. 260 if (!( symb 261 && SymbolTableSection 262 && symb >= (const Elf_Sym*)(base() 263 + SymbolTableSection->sh_offset) 264 && symb < (const Elf_Sym*)(base() 265 + SymbolTableSection->sh_offset 266 + SymbolTableSection->sh_size))) 267 // FIXME: Proper error handling. 268 report_fatal_error("Symb must point to a valid symbol!"); 269 } 270 271 template<support::endianness target_endianness, bool is64Bits> 272 error_code ELFObjectFile<target_endianness, is64Bits> 273 ::getSymbolNext(DataRefImpl Symb, 274 SymbolRef &Result) const { 275 validateSymbol(Symb); 276 const Elf_Shdr *SymbolTableSection = SymbolTableSections[Symb.d.b]; 277 278 ++Symb.d.a; 279 // Check to see if we are at the end of this symbol table. 280 if (Symb.d.a >= SymbolTableSection->getEntityCount()) { 281 // We are at the end. If there are other symbol tables, jump to them. 282 ++Symb.d.b; 283 Symb.d.a = 1; // The 0th symbol in ELF is fake. 284 // Otherwise return the terminator. 285 if (Symb.d.b >= SymbolTableSections.size()) { 286 Symb.d.a = std::numeric_limits<uint32_t>::max(); 287 Symb.d.b = std::numeric_limits<uint32_t>::max(); 288 } 289 } 290 291 Result = SymbolRef(Symb, this); 292 return object_error::success; 293 } 294 295 template<support::endianness target_endianness, bool is64Bits> 296 error_code ELFObjectFile<target_endianness, is64Bits> 297 ::getSymbolName(DataRefImpl Symb, 298 StringRef &Result) const { 299 validateSymbol(Symb); 300 const Elf_Sym *symb = getSymbol(Symb); 301 if (symb->st_name == 0) { 302 const Elf_Shdr *section = getSection(symb->st_shndx); 303 if (!section) 304 Result = ""; 305 else 306 Result = getString(dot_shstrtab_sec, section->sh_name); 307 return object_error::success; 308 } 309 310 // Use the default symbol table name section. 311 Result = getString(dot_strtab_sec, symb->st_name); 312 return object_error::success; 313 } 314 315 template<support::endianness target_endianness, bool is64Bits> 316 error_code ELFObjectFile<target_endianness, is64Bits> 317 ::getSymbolAddress(DataRefImpl Symb, 318 uint64_t &Result) const { 319 validateSymbol(Symb); 320 const Elf_Sym *symb = getSymbol(Symb); 321 const Elf_Shdr *Section; 322 switch (symb->st_shndx) { 323 case ELF::SHN_COMMON: 324 // Undefined symbols have no address yet. 325 case ELF::SHN_UNDEF: 326 Result = UnknownAddressOrSize; 327 return object_error::success; 328 case ELF::SHN_ABS: 329 Result = symb->st_value; 330 return object_error::success; 331 default: Section = getSection(symb->st_shndx); 332 } 333 334 switch (symb->getType()) { 335 case ELF::STT_SECTION: 336 Result = Section ? Section->sh_addr : UnknownAddressOrSize; 337 return object_error::success; 338 case ELF::STT_FUNC: 339 case ELF::STT_OBJECT: 340 case ELF::STT_NOTYPE: 341 Result = symb->st_value; 342 return object_error::success; 343 default: 344 Result = UnknownAddressOrSize; 345 return object_error::success; 346 } 347 } 348 349 template<support::endianness target_endianness, bool is64Bits> 350 error_code ELFObjectFile<target_endianness, is64Bits> 351 ::getSymbolSize(DataRefImpl Symb, 352 uint64_t &Result) const { 353 validateSymbol(Symb); 354 const Elf_Sym *symb = getSymbol(Symb); 355 if (symb->st_size == 0) 356 Result = UnknownAddressOrSize; 357 Result = symb->st_size; 358 return object_error::success; 359 } 360 361 template<support::endianness target_endianness, bool is64Bits> 362 error_code ELFObjectFile<target_endianness, is64Bits> 363 ::getSymbolNMTypeChar(DataRefImpl Symb, 364 char &Result) const { 365 validateSymbol(Symb); 366 const Elf_Sym *symb = getSymbol(Symb); 367 const Elf_Shdr *Section = getSection(symb->st_shndx); 368 369 char ret = '?'; 370 371 if (Section) { 372 switch (Section->sh_type) { 373 case ELF::SHT_PROGBITS: 374 case ELF::SHT_DYNAMIC: 375 switch (Section->sh_flags) { 376 case (ELF::SHF_ALLOC | ELF::SHF_EXECINSTR): 377 ret = 't'; break; 378 case (ELF::SHF_ALLOC | ELF::SHF_WRITE): 379 ret = 'd'; break; 380 case ELF::SHF_ALLOC: 381 case (ELF::SHF_ALLOC | ELF::SHF_MERGE): 382 case (ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::SHF_STRINGS): 383 ret = 'r'; break; 384 } 385 break; 386 case ELF::SHT_NOBITS: ret = 'b'; 387 } 388 } 389 390 switch (symb->st_shndx) { 391 case ELF::SHN_UNDEF: 392 if (ret == '?') 393 ret = 'U'; 394 break; 395 case ELF::SHN_ABS: ret = 'a'; break; 396 case ELF::SHN_COMMON: ret = 'c'; break; 397 } 398 399 switch (symb->getBinding()) { 400 case ELF::STB_GLOBAL: ret = ::toupper(ret); break; 401 case ELF::STB_WEAK: 402 if (symb->st_shndx == ELF::SHN_UNDEF) 403 ret = 'w'; 404 else 405 if (symb->getType() == ELF::STT_OBJECT) 406 ret = 'V'; 407 else 408 ret = 'W'; 409 } 410 411 if (ret == '?' && symb->getType() == ELF::STT_SECTION) { 412 StringRef name; 413 if (error_code ec = getSymbolName(Symb, name)) 414 return ec; 415 Result = StringSwitch<char>(name) 416 .StartsWith(".debug", 'N') 417 .StartsWith(".note", 'n'); 418 return object_error::success; 419 } 420 421 Result = ret; 422 return object_error::success; 423 } 424 425 template<support::endianness target_endianness, bool is64Bits> 426 error_code ELFObjectFile<target_endianness, is64Bits> 427 ::isSymbolInternal(DataRefImpl Symb, 428 bool &Result) const { 429 validateSymbol(Symb); 430 const Elf_Sym *symb = getSymbol(Symb); 431 432 if ( symb->getType() == ELF::STT_FILE 433 || symb->getType() == ELF::STT_SECTION) 434 Result = true; 435 Result = false; 436 return object_error::success; 437 } 438 439 template<support::endianness target_endianness, bool is64Bits> 440 error_code ELFObjectFile<target_endianness, is64Bits> 441 ::getSectionNext(DataRefImpl Sec, SectionRef &Result) const { 442 const uint8_t *sec = reinterpret_cast<const uint8_t *>(Sec.p); 443 sec += Header->e_shentsize; 444 Sec.p = reinterpret_cast<intptr_t>(sec); 445 Result = SectionRef(Sec, this); 446 return object_error::success; 447 } 448 449 template<support::endianness target_endianness, bool is64Bits> 450 error_code ELFObjectFile<target_endianness, is64Bits> 451 ::getSectionName(DataRefImpl Sec, 452 StringRef &Result) const { 453 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 454 Result = StringRef(getString(dot_shstrtab_sec, sec->sh_name)); 455 return object_error::success; 456 } 457 458 template<support::endianness target_endianness, bool is64Bits> 459 error_code ELFObjectFile<target_endianness, is64Bits> 460 ::getSectionAddress(DataRefImpl Sec, 461 uint64_t &Result) const { 462 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 463 Result = sec->sh_addr; 464 return object_error::success; 465 } 466 467 template<support::endianness target_endianness, bool is64Bits> 468 error_code ELFObjectFile<target_endianness, is64Bits> 469 ::getSectionSize(DataRefImpl Sec, 470 uint64_t &Result) const { 471 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 472 Result = sec->sh_size; 473 return object_error::success; 474 } 475 476 template<support::endianness target_endianness, bool is64Bits> 477 error_code ELFObjectFile<target_endianness, is64Bits> 478 ::getSectionContents(DataRefImpl Sec, 479 StringRef &Result) const { 480 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 481 const char *start = (const char*)base() + sec->sh_offset; 482 Result = StringRef(start, sec->sh_size); 483 return object_error::success; 484 } 485 486 template<support::endianness target_endianness, bool is64Bits> 487 error_code ELFObjectFile<target_endianness, is64Bits> 488 ::isSectionText(DataRefImpl Sec, 489 bool &Result) const { 490 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 491 if (sec->sh_flags & ELF::SHF_EXECINSTR) 492 Result = true; 493 else 494 Result = false; 495 return object_error::success; 496 } 497 498 template<support::endianness target_endianness, bool is64Bits> 499 ELFObjectFile<target_endianness, is64Bits>::ELFObjectFile(MemoryBuffer *Object 500 , error_code &ec) 501 : ObjectFile(Binary::isELF, Object, ec) 502 , SectionHeaderTable(0) 503 , dot_shstrtab_sec(0) 504 , dot_strtab_sec(0) { 505 Header = reinterpret_cast<const Elf_Ehdr *>(base()); 506 507 if (Header->e_shoff == 0) 508 return; 509 510 SectionHeaderTable = 511 reinterpret_cast<const Elf_Shdr *>(base() + Header->e_shoff); 512 uint32_t SectionTableSize = Header->e_shnum * Header->e_shentsize; 513 if (!( (const uint8_t *)SectionHeaderTable + SectionTableSize 514 <= base() + Data->getBufferSize())) 515 // FIXME: Proper error handling. 516 report_fatal_error("Section table goes past end of file!"); 517 518 519 // To find the symbol tables we walk the section table to find SHT_STMTAB. 520 for (const char *i = reinterpret_cast<const char *>(SectionHeaderTable), 521 *e = i + Header->e_shnum * Header->e_shentsize; 522 i != e; i += Header->e_shentsize) { 523 const Elf_Shdr *sh = reinterpret_cast<const Elf_Shdr*>(i); 524 if (sh->sh_type == ELF::SHT_SYMTAB) { 525 SymbolTableSections.push_back(sh); 526 } 527 } 528 529 // Get string table sections. 530 dot_shstrtab_sec = getSection(Header->e_shstrndx); 531 if (dot_shstrtab_sec) { 532 // Verify that the last byte in the string table in a null. 533 if (((const char*)base() + dot_shstrtab_sec->sh_offset) 534 [dot_shstrtab_sec->sh_size - 1] != 0) 535 // FIXME: Proper error handling. 536 report_fatal_error("String table must end with a null terminator!"); 537 } 538 539 // Merge this into the above loop. 540 for (const char *i = reinterpret_cast<const char *>(SectionHeaderTable), 541 *e = i + Header->e_shnum * Header->e_shentsize; 542 i != e; i += Header->e_shentsize) { 543 const Elf_Shdr *sh = reinterpret_cast<const Elf_Shdr*>(i); 544 if (sh->sh_type == ELF::SHT_STRTAB) { 545 StringRef SectionName(getString(dot_shstrtab_sec, sh->sh_name)); 546 if (SectionName == ".strtab") { 547 if (dot_strtab_sec != 0) 548 // FIXME: Proper error handling. 549 report_fatal_error("Already found section named .strtab!"); 550 dot_strtab_sec = sh; 551 const char *dot_strtab = (const char*)base() + sh->sh_offset; 552 if (dot_strtab[sh->sh_size - 1] != 0) 553 // FIXME: Proper error handling. 554 report_fatal_error("String table must end with a null terminator!"); 555 } 556 } 557 } 558 } 559 560 template<support::endianness target_endianness, bool is64Bits> 561 ObjectFile::symbol_iterator ELFObjectFile<target_endianness, is64Bits> 562 ::begin_symbols() const { 563 DataRefImpl SymbolData; 564 memset(&SymbolData, 0, sizeof(SymbolData)); 565 if (SymbolTableSections.size() == 0) { 566 SymbolData.d.a = std::numeric_limits<uint32_t>::max(); 567 SymbolData.d.b = std::numeric_limits<uint32_t>::max(); 568 } else { 569 SymbolData.d.a = 1; // The 0th symbol in ELF is fake. 570 SymbolData.d.b = 0; 571 } 572 return symbol_iterator(SymbolRef(SymbolData, this)); 573 } 574 575 template<support::endianness target_endianness, bool is64Bits> 576 ObjectFile::symbol_iterator ELFObjectFile<target_endianness, is64Bits> 577 ::end_symbols() const { 578 DataRefImpl SymbolData; 579 memset(&SymbolData, 0, sizeof(SymbolData)); 580 SymbolData.d.a = std::numeric_limits<uint32_t>::max(); 581 SymbolData.d.b = std::numeric_limits<uint32_t>::max(); 582 return symbol_iterator(SymbolRef(SymbolData, this)); 583 } 584 585 template<support::endianness target_endianness, bool is64Bits> 586 ObjectFile::section_iterator ELFObjectFile<target_endianness, is64Bits> 587 ::begin_sections() const { 588 DataRefImpl ret; 589 memset(&ret, 0, sizeof(DataRefImpl)); 590 ret.p = reinterpret_cast<intptr_t>(base() + Header->e_shoff); 591 return section_iterator(SectionRef(ret, this)); 592 } 593 594 template<support::endianness target_endianness, bool is64Bits> 595 ObjectFile::section_iterator ELFObjectFile<target_endianness, is64Bits> 596 ::end_sections() const { 597 DataRefImpl ret; 598 memset(&ret, 0, sizeof(DataRefImpl)); 599 ret.p = reinterpret_cast<intptr_t>(base() 600 + Header->e_shoff 601 + (Header->e_shentsize * Header->e_shnum)); 602 return section_iterator(SectionRef(ret, this)); 603 } 604 605 template<support::endianness target_endianness, bool is64Bits> 606 uint8_t ELFObjectFile<target_endianness, is64Bits>::getBytesInAddress() const { 607 return is64Bits ? 8 : 4; 608 } 609 610 template<support::endianness target_endianness, bool is64Bits> 611 StringRef ELFObjectFile<target_endianness, is64Bits> 612 ::getFileFormatName() const { 613 switch(Header->e_ident[ELF::EI_CLASS]) { 614 case ELF::ELFCLASS32: 615 switch(Header->e_machine) { 616 case ELF::EM_386: 617 return "ELF32-i386"; 618 case ELF::EM_X86_64: 619 return "ELF32-x86-64"; 620 default: 621 return "ELF32-unknown"; 622 } 623 case ELF::ELFCLASS64: 624 switch(Header->e_machine) { 625 case ELF::EM_386: 626 return "ELF64-i386"; 627 case ELF::EM_X86_64: 628 return "ELF64-x86-64"; 629 default: 630 return "ELF64-unknown"; 631 } 632 default: 633 // FIXME: Proper error handling. 634 report_fatal_error("Invalid ELFCLASS!"); 635 } 636 } 637 638 template<support::endianness target_endianness, bool is64Bits> 639 unsigned ELFObjectFile<target_endianness, is64Bits>::getArch() const { 640 switch(Header->e_machine) { 641 case ELF::EM_386: 642 return Triple::x86; 643 case ELF::EM_X86_64: 644 return Triple::x86_64; 645 default: 646 return Triple::UnknownArch; 647 } 648 } 649 650 template<support::endianness target_endianness, bool is64Bits> 651 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Sym * 652 ELFObjectFile<target_endianness, is64Bits>::getSymbol(DataRefImpl Symb) const { 653 const Elf_Shdr *sec = SymbolTableSections[Symb.d.b]; 654 return reinterpret_cast<const Elf_Sym *>( 655 base() 656 + sec->sh_offset 657 + (Symb.d.a * sec->sh_entsize)); 658 } 659 660 template<support::endianness target_endianness, bool is64Bits> 661 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Shdr * 662 ELFObjectFile<target_endianness, is64Bits>::getSection(DataRefImpl Symb) const { 663 const Elf_Shdr *sec = getSection(Symb.d.b); 664 if (sec->sh_type != ELF::SHT_SYMTAB) 665 // FIXME: Proper error handling. 666 report_fatal_error("Invalid symbol table section!"); 667 return sec; 668 } 669 670 template<support::endianness target_endianness, bool is64Bits> 671 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Shdr * 672 ELFObjectFile<target_endianness, is64Bits>::getSection(uint16_t index) const { 673 if (index == 0 || index >= ELF::SHN_LORESERVE) 674 return 0; 675 if (!SectionHeaderTable || index >= Header->e_shnum) 676 // FIXME: Proper error handling. 677 report_fatal_error("Invalid section index!"); 678 679 return reinterpret_cast<const Elf_Shdr *>( 680 reinterpret_cast<const char *>(SectionHeaderTable) 681 + (index * Header->e_shentsize)); 682 } 683 684 template<support::endianness target_endianness, bool is64Bits> 685 const char *ELFObjectFile<target_endianness, is64Bits> 686 ::getString(uint16_t section, 687 ELF::Elf32_Word offset) const { 688 return getString(getSection(section), offset); 689 } 690 691 template<support::endianness target_endianness, bool is64Bits> 692 const char *ELFObjectFile<target_endianness, is64Bits> 693 ::getString(const Elf_Shdr *section, 694 ELF::Elf32_Word offset) const { 695 assert(section && section->sh_type == ELF::SHT_STRTAB && "Invalid section!"); 696 if (offset >= section->sh_size) 697 // FIXME: Proper error handling. 698 report_fatal_error("Symbol name offset outside of string table!"); 699 return (const char *)base() + section->sh_offset + offset; 700 } 701 702 // EI_CLASS, EI_DATA. 703 static std::pair<unsigned char, unsigned char> 704 getElfArchType(MemoryBuffer *Object) { 705 if (Object->getBufferSize() < ELF::EI_NIDENT) 706 return std::make_pair((uint8_t)ELF::ELFCLASSNONE,(uint8_t)ELF::ELFDATANONE); 707 return std::make_pair( (uint8_t)Object->getBufferStart()[ELF::EI_CLASS] 708 , (uint8_t)Object->getBufferStart()[ELF::EI_DATA]); 709 } 710 711 namespace llvm { 712 713 ObjectFile *ObjectFile::createELFObjectFile(MemoryBuffer *Object) { 714 std::pair<unsigned char, unsigned char> Ident = getElfArchType(Object); 715 error_code ec; 716 if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB) 717 return new ELFObjectFile<support::little, false>(Object, ec); 718 else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB) 719 return new ELFObjectFile<support::big, false>(Object, ec); 720 else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) 721 return new ELFObjectFile<support::little, true>(Object, ec); 722 else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB) 723 return new ELFObjectFile<support::big, true>(Object, ec); 724 // FIXME: Proper error handling. 725 report_fatal_error("Not an ELF object file!"); 726 } 727 728 } // end namespace llvm 729