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/ADT/DenseMap.h" 18 #include "llvm/Object/ObjectFile.h" 19 #include "llvm/Support/ELF.h" 20 #include "llvm/Support/Endian.h" 21 #include "llvm/Support/ErrorHandling.h" 22 #include "llvm/Support/MemoryBuffer.h" 23 #include <limits> 24 #include <utility> 25 26 using namespace llvm; 27 using namespace object; 28 29 // Templates to choose Elf_Addr and Elf_Off depending on is64Bits. 30 namespace { 31 template<support::endianness target_endianness> 32 struct ELFDataTypeTypedefHelperCommon { 33 typedef support::detail::packed_endian_specific_integral 34 <uint16_t, target_endianness, support::aligned> Elf_Half; 35 typedef support::detail::packed_endian_specific_integral 36 <uint32_t, target_endianness, support::aligned> Elf_Word; 37 typedef support::detail::packed_endian_specific_integral 38 <int32_t, target_endianness, support::aligned> Elf_Sword; 39 typedef support::detail::packed_endian_specific_integral 40 <uint64_t, target_endianness, support::aligned> Elf_Xword; 41 typedef support::detail::packed_endian_specific_integral 42 <int64_t, target_endianness, support::aligned> Elf_Sxword; 43 }; 44 } 45 46 namespace { 47 template<support::endianness target_endianness, bool is64Bits> 48 struct ELFDataTypeTypedefHelper; 49 50 /// ELF 32bit types. 51 template<support::endianness target_endianness> 52 struct ELFDataTypeTypedefHelper<target_endianness, false> 53 : ELFDataTypeTypedefHelperCommon<target_endianness> { 54 typedef support::detail::packed_endian_specific_integral 55 <uint32_t, target_endianness, support::aligned> Elf_Addr; 56 typedef support::detail::packed_endian_specific_integral 57 <uint32_t, target_endianness, support::aligned> Elf_Off; 58 }; 59 60 /// ELF 64bit types. 61 template<support::endianness target_endianness> 62 struct ELFDataTypeTypedefHelper<target_endianness, true> 63 : ELFDataTypeTypedefHelperCommon<target_endianness>{ 64 typedef support::detail::packed_endian_specific_integral 65 <uint64_t, target_endianness, support::aligned> Elf_Addr; 66 typedef support::detail::packed_endian_specific_integral 67 <uint64_t, target_endianness, support::aligned> Elf_Off; 68 }; 69 } 70 71 // I really don't like doing this, but the alternative is copypasta. 72 #define LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits) \ 73 typedef typename \ 74 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Addr Elf_Addr; \ 75 typedef typename \ 76 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Off Elf_Off; \ 77 typedef typename \ 78 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Half Elf_Half; \ 79 typedef typename \ 80 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Word Elf_Word; \ 81 typedef typename \ 82 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Sword Elf_Sword; \ 83 typedef typename \ 84 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Xword Elf_Xword; \ 85 typedef typename \ 86 ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Sxword Elf_Sxword; 87 88 // Section header. 89 namespace { 90 template<support::endianness target_endianness, bool is64Bits> 91 struct Elf_Shdr_Base; 92 93 template<support::endianness target_endianness> 94 struct Elf_Shdr_Base<target_endianness, false> { 95 LLVM_ELF_IMPORT_TYPES(target_endianness, false) 96 Elf_Word sh_name; // Section name (index into string table) 97 Elf_Word sh_type; // Section type (SHT_*) 98 Elf_Word sh_flags; // Section flags (SHF_*) 99 Elf_Addr sh_addr; // Address where section is to be loaded 100 Elf_Off sh_offset; // File offset of section data, in bytes 101 Elf_Word sh_size; // Size of section, in bytes 102 Elf_Word sh_link; // Section type-specific header table index link 103 Elf_Word sh_info; // Section type-specific extra information 104 Elf_Word sh_addralign;// Section address alignment 105 Elf_Word sh_entsize; // Size of records contained within the section 106 }; 107 108 template<support::endianness target_endianness> 109 struct Elf_Shdr_Base<target_endianness, true> { 110 LLVM_ELF_IMPORT_TYPES(target_endianness, true) 111 Elf_Word sh_name; // Section name (index into string table) 112 Elf_Word sh_type; // Section type (SHT_*) 113 Elf_Xword sh_flags; // Section flags (SHF_*) 114 Elf_Addr sh_addr; // Address where section is to be loaded 115 Elf_Off sh_offset; // File offset of section data, in bytes 116 Elf_Xword sh_size; // Size of section, in bytes 117 Elf_Word sh_link; // Section type-specific header table index link 118 Elf_Word sh_info; // Section type-specific extra information 119 Elf_Xword sh_addralign;// Section address alignment 120 Elf_Xword sh_entsize; // Size of records contained within the section 121 }; 122 123 template<support::endianness target_endianness, bool is64Bits> 124 struct Elf_Shdr_Impl : Elf_Shdr_Base<target_endianness, is64Bits> { 125 using Elf_Shdr_Base<target_endianness, is64Bits>::sh_entsize; 126 using Elf_Shdr_Base<target_endianness, is64Bits>::sh_size; 127 128 /// @brief Get the number of entities this section contains if it has any. 129 unsigned getEntityCount() const { 130 if (sh_entsize == 0) 131 return 0; 132 return sh_size / sh_entsize; 133 } 134 }; 135 } 136 137 namespace { 138 template<support::endianness target_endianness, bool is64Bits> 139 struct Elf_Sym_Base; 140 141 template<support::endianness target_endianness> 142 struct Elf_Sym_Base<target_endianness, false> { 143 LLVM_ELF_IMPORT_TYPES(target_endianness, false) 144 Elf_Word st_name; // Symbol name (index into string table) 145 Elf_Addr st_value; // Value or address associated with the symbol 146 Elf_Word st_size; // Size of the symbol 147 unsigned char st_info; // Symbol's type and binding attributes 148 unsigned char st_other; // Must be zero; reserved 149 Elf_Half st_shndx; // Which section (header table index) it's defined in 150 }; 151 152 template<support::endianness target_endianness> 153 struct Elf_Sym_Base<target_endianness, true> { 154 LLVM_ELF_IMPORT_TYPES(target_endianness, true) 155 Elf_Word st_name; // Symbol name (index into string table) 156 unsigned char st_info; // Symbol's type and binding attributes 157 unsigned char st_other; // Must be zero; reserved 158 Elf_Half st_shndx; // Which section (header table index) it's defined in 159 Elf_Addr st_value; // Value or address associated with the symbol 160 Elf_Xword st_size; // Size of the symbol 161 }; 162 163 template<support::endianness target_endianness, bool is64Bits> 164 struct Elf_Sym_Impl : Elf_Sym_Base<target_endianness, is64Bits> { 165 using Elf_Sym_Base<target_endianness, is64Bits>::st_info; 166 167 // These accessors and mutators correspond to the ELF32_ST_BIND, 168 // ELF32_ST_TYPE, and ELF32_ST_INFO macros defined in the ELF specification: 169 unsigned char getBinding() const { return st_info >> 4; } 170 unsigned char getType() const { return st_info & 0x0f; } 171 void setBinding(unsigned char b) { setBindingAndType(b, getType()); } 172 void setType(unsigned char t) { setBindingAndType(getBinding(), t); } 173 void setBindingAndType(unsigned char b, unsigned char t) { 174 st_info = (b << 4) + (t & 0x0f); 175 } 176 }; 177 } 178 179 namespace { 180 template<support::endianness target_endianness, bool is64Bits, bool isRela> 181 struct Elf_Rel_Base; 182 183 template<support::endianness target_endianness> 184 struct Elf_Rel_Base<target_endianness, false, false> { 185 LLVM_ELF_IMPORT_TYPES(target_endianness, false) 186 Elf_Addr r_offset; // Location (file byte offset, or program virtual addr) 187 Elf_Word r_info; // Symbol table index and type of relocation to apply 188 }; 189 190 template<support::endianness target_endianness> 191 struct Elf_Rel_Base<target_endianness, true, false> { 192 LLVM_ELF_IMPORT_TYPES(target_endianness, true) 193 Elf_Addr r_offset; // Location (file byte offset, or program virtual addr) 194 Elf_Xword r_info; // Symbol table index and type of relocation to apply 195 }; 196 197 template<support::endianness target_endianness> 198 struct Elf_Rel_Base<target_endianness, false, true> { 199 LLVM_ELF_IMPORT_TYPES(target_endianness, false) 200 Elf_Addr r_offset; // Location (file byte offset, or program virtual addr) 201 Elf_Word r_info; // Symbol table index and type of relocation to apply 202 Elf_Sword r_addend; // Compute value for relocatable field by adding this 203 }; 204 205 template<support::endianness target_endianness> 206 struct Elf_Rel_Base<target_endianness, true, true> { 207 LLVM_ELF_IMPORT_TYPES(target_endianness, true) 208 Elf_Addr r_offset; // Location (file byte offset, or program virtual addr) 209 Elf_Xword r_info; // Symbol table index and type of relocation to apply 210 Elf_Sxword r_addend; // Compute value for relocatable field by adding this. 211 }; 212 213 template<support::endianness target_endianness, bool is64Bits, bool isRela> 214 struct Elf_Rel_Impl; 215 216 template<support::endianness target_endianness, bool isRela> 217 struct Elf_Rel_Impl<target_endianness, true, isRela> 218 : Elf_Rel_Base<target_endianness, true, isRela> { 219 using Elf_Rel_Base<target_endianness, true, isRela>::r_info; 220 LLVM_ELF_IMPORT_TYPES(target_endianness, true) 221 222 // These accessors and mutators correspond to the ELF64_R_SYM, ELF64_R_TYPE, 223 // and ELF64_R_INFO macros defined in the ELF specification: 224 uint64_t getSymbol() const { return (r_info >> 32); } 225 unsigned char getType() const { 226 return (unsigned char) (r_info & 0xffffffffL); 227 } 228 void setSymbol(uint64_t s) { setSymbolAndType(s, getType()); } 229 void setType(unsigned char t) { setSymbolAndType(getSymbol(), t); } 230 void setSymbolAndType(uint64_t s, unsigned char t) { 231 r_info = (s << 32) + (t&0xffffffffL); 232 } 233 }; 234 235 template<support::endianness target_endianness, bool isRela> 236 struct Elf_Rel_Impl<target_endianness, false, isRela> 237 : Elf_Rel_Base<target_endianness, false, isRela> { 238 using Elf_Rel_Base<target_endianness, false, isRela>::r_info; 239 LLVM_ELF_IMPORT_TYPES(target_endianness, false) 240 241 // These accessors and mutators correspond to the ELF32_R_SYM, ELF32_R_TYPE, 242 // and ELF32_R_INFO macros defined in the ELF specification: 243 uint32_t getSymbol() const { return (r_info >> 8); } 244 unsigned char getType() const { return (unsigned char) (r_info & 0x0ff); } 245 void setSymbol(uint32_t s) { setSymbolAndType(s, getType()); } 246 void setType(unsigned char t) { setSymbolAndType(getSymbol(), t); } 247 void setSymbolAndType(uint32_t s, unsigned char t) { 248 r_info = (s << 8) + t; 249 } 250 }; 251 252 } 253 254 namespace { 255 template<support::endianness target_endianness, bool is64Bits> 256 class ELFObjectFile : public ObjectFile { 257 LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits) 258 259 typedef Elf_Shdr_Impl<target_endianness, is64Bits> Elf_Shdr; 260 typedef Elf_Sym_Impl<target_endianness, is64Bits> Elf_Sym; 261 typedef Elf_Rel_Impl<target_endianness, is64Bits, false> Elf_Rel; 262 typedef Elf_Rel_Impl<target_endianness, is64Bits, true> Elf_Rela; 263 264 struct Elf_Ehdr { 265 unsigned char e_ident[ELF::EI_NIDENT]; // ELF Identification bytes 266 Elf_Half e_type; // Type of file (see ET_*) 267 Elf_Half e_machine; // Required architecture for this file (see EM_*) 268 Elf_Word e_version; // Must be equal to 1 269 Elf_Addr e_entry; // Address to jump to in order to start program 270 Elf_Off e_phoff; // Program header table's file offset, in bytes 271 Elf_Off e_shoff; // Section header table's file offset, in bytes 272 Elf_Word e_flags; // Processor-specific flags 273 Elf_Half e_ehsize; // Size of ELF header, in bytes 274 Elf_Half e_phentsize;// Size of an entry in the program header table 275 Elf_Half e_phnum; // Number of entries in the program header table 276 Elf_Half e_shentsize;// Size of an entry in the section header table 277 Elf_Half e_shnum; // Number of entries in the section header table 278 Elf_Half e_shstrndx; // Section header table index of section name 279 // string table 280 bool checkMagic() const { 281 return (memcmp(e_ident, ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0; 282 } 283 unsigned char getFileClass() const { return e_ident[ELF::EI_CLASS]; } 284 unsigned char getDataEncoding() const { return e_ident[ELF::EI_DATA]; } 285 }; 286 287 typedef SmallVector<const Elf_Shdr*, 1> Sections_t; 288 typedef DenseMap<unsigned, unsigned> IndexMap_t; 289 290 const Elf_Ehdr *Header; 291 const Elf_Shdr *SectionHeaderTable; 292 const Elf_Shdr *dot_shstrtab_sec; // Section header string table. 293 const Elf_Shdr *dot_strtab_sec; // Symbol header string table. 294 Sections_t SymbolTableSections; 295 IndexMap_t SymbolTableSectionsIndexMap; 296 Sections_t RelocationTableSections; 297 298 void validateSymbol(DataRefImpl Symb) const; 299 bool isRelocationHasAddend(DataRefImpl Rel) const; 300 template<typename T> 301 const T *getEntry(DataRefImpl Entry, Sections_t Sections) const; 302 const Elf_Sym *getSymbol(DataRefImpl Symb) const; 303 const Elf_Shdr *getSection(DataRefImpl index) const; 304 const Elf_Shdr *getSection(uint16_t index) const; 305 const Elf_Rel *getRel(DataRefImpl Rel) const; 306 const Elf_Rela *getRela(DataRefImpl Rela) const; 307 const char *getString(uint16_t section, uint32_t offset) const; 308 const char *getString(const Elf_Shdr *section, uint32_t offset) const; 309 310 protected: 311 virtual error_code getSymbolNext(DataRefImpl Symb, SymbolRef &Res) const; 312 virtual error_code getSymbolName(DataRefImpl Symb, StringRef &Res) const; 313 virtual error_code getSymbolOffset(DataRefImpl Symb, uint64_t &Res) const; 314 virtual error_code getSymbolAddress(DataRefImpl Symb, uint64_t &Res) const; 315 virtual error_code getSymbolSize(DataRefImpl Symb, uint64_t &Res) const; 316 virtual error_code getSymbolNMTypeChar(DataRefImpl Symb, char &Res) const; 317 virtual error_code isSymbolInternal(DataRefImpl Symb, bool &Res) const; 318 virtual error_code isSymbolGlobal(DataRefImpl Symb, bool &Res) const; 319 virtual error_code getSymbolType(DataRefImpl Symb, SymbolRef::SymbolType &Res) const; 320 321 virtual error_code getSectionNext(DataRefImpl Sec, SectionRef &Res) const; 322 virtual error_code getSectionName(DataRefImpl Sec, StringRef &Res) const; 323 virtual error_code getSectionAddress(DataRefImpl Sec, uint64_t &Res) const; 324 virtual error_code getSectionSize(DataRefImpl Sec, uint64_t &Res) const; 325 virtual error_code getSectionContents(DataRefImpl Sec, StringRef &Res) const; 326 virtual error_code isSectionText(DataRefImpl Sec, bool &Res) const; 327 virtual error_code sectionContainsSymbol(DataRefImpl Sec, DataRefImpl Symb, 328 bool &Result) const; 329 330 virtual error_code getRelocationNext(DataRefImpl Rel, 331 RelocationRef &Res) const; 332 virtual error_code getRelocationAddress(DataRefImpl Rel, 333 uint64_t &Res) const; 334 virtual error_code getRelocationSymbol(DataRefImpl Rel, 335 SymbolRef &Res) const; 336 virtual error_code getRelocationType(DataRefImpl Rel, 337 uint32_t &Res) const; 338 virtual error_code getRelocationAdditionalInfo(DataRefImpl Rel, 339 int64_t &Res) const; 340 341 public: 342 ELFObjectFile(MemoryBuffer *Object, error_code &ec); 343 virtual symbol_iterator begin_symbols() const; 344 virtual symbol_iterator end_symbols() const; 345 virtual section_iterator begin_sections() const; 346 virtual section_iterator end_sections() const; 347 virtual relocation_iterator begin_relocations() const; 348 virtual relocation_iterator end_relocations() const; 349 350 virtual uint8_t getBytesInAddress() const; 351 virtual StringRef getFileFormatName() const; 352 virtual unsigned getArch() const; 353 }; 354 } // end namespace 355 356 template<support::endianness target_endianness, bool is64Bits> 357 void ELFObjectFile<target_endianness, is64Bits> 358 ::validateSymbol(DataRefImpl Symb) const { 359 const Elf_Sym *symb = getSymbol(Symb); 360 const Elf_Shdr *SymbolTableSection = SymbolTableSections[Symb.d.b]; 361 // FIXME: We really need to do proper error handling in the case of an invalid 362 // input file. Because we don't use exceptions, I think we'll just pass 363 // an error object around. 364 if (!( symb 365 && SymbolTableSection 366 && symb >= (const Elf_Sym*)(base() 367 + SymbolTableSection->sh_offset) 368 && symb < (const Elf_Sym*)(base() 369 + SymbolTableSection->sh_offset 370 + SymbolTableSection->sh_size))) 371 // FIXME: Proper error handling. 372 report_fatal_error("Symb must point to a valid symbol!"); 373 } 374 375 template<support::endianness target_endianness, bool is64Bits> 376 error_code ELFObjectFile<target_endianness, is64Bits> 377 ::getSymbolNext(DataRefImpl Symb, 378 SymbolRef &Result) const { 379 validateSymbol(Symb); 380 const Elf_Shdr *SymbolTableSection = SymbolTableSections[Symb.d.b]; 381 382 ++Symb.d.a; 383 // Check to see if we are at the end of this symbol table. 384 if (Symb.d.a >= SymbolTableSection->getEntityCount()) { 385 // We are at the end. If there are other symbol tables, jump to them. 386 ++Symb.d.b; 387 Symb.d.a = 1; // The 0th symbol in ELF is fake. 388 // Otherwise return the terminator. 389 if (Symb.d.b >= SymbolTableSections.size()) { 390 Symb.d.a = std::numeric_limits<uint32_t>::max(); 391 Symb.d.b = std::numeric_limits<uint32_t>::max(); 392 } 393 } 394 395 Result = SymbolRef(Symb, this); 396 return object_error::success; 397 } 398 399 template<support::endianness target_endianness, bool is64Bits> 400 error_code ELFObjectFile<target_endianness, is64Bits> 401 ::getSymbolName(DataRefImpl Symb, 402 StringRef &Result) const { 403 validateSymbol(Symb); 404 const Elf_Sym *symb = getSymbol(Symb); 405 if (symb->st_name == 0) { 406 const Elf_Shdr *section = getSection(symb->st_shndx); 407 if (!section) 408 Result = ""; 409 else 410 Result = getString(dot_shstrtab_sec, section->sh_name); 411 return object_error::success; 412 } 413 414 // Use the default symbol table name section. 415 Result = getString(dot_strtab_sec, symb->st_name); 416 return object_error::success; 417 } 418 419 template<support::endianness target_endianness, bool is64Bits> 420 error_code ELFObjectFile<target_endianness, is64Bits> 421 ::getSymbolOffset(DataRefImpl Symb, 422 uint64_t &Result) const { 423 validateSymbol(Symb); 424 const Elf_Sym *symb = getSymbol(Symb); 425 const Elf_Shdr *Section; 426 switch (symb->st_shndx) { 427 case ELF::SHN_COMMON: 428 // Undefined symbols have no address yet. 429 case ELF::SHN_UNDEF: 430 Result = UnknownAddressOrSize; 431 return object_error::success; 432 case ELF::SHN_ABS: 433 Result = symb->st_value; 434 return object_error::success; 435 default: Section = getSection(symb->st_shndx); 436 } 437 438 switch (symb->getType()) { 439 case ELF::STT_SECTION: 440 Result = Section ? Section->sh_addr : UnknownAddressOrSize; 441 return object_error::success; 442 case ELF::STT_FUNC: 443 case ELF::STT_OBJECT: 444 case ELF::STT_NOTYPE: 445 Result = symb->st_value; 446 return object_error::success; 447 default: 448 Result = UnknownAddressOrSize; 449 return object_error::success; 450 } 451 } 452 453 template<support::endianness target_endianness, bool is64Bits> 454 error_code ELFObjectFile<target_endianness, is64Bits> 455 ::getSymbolAddress(DataRefImpl Symb, 456 uint64_t &Result) const { 457 validateSymbol(Symb); 458 const Elf_Sym *symb = getSymbol(Symb); 459 const Elf_Shdr *Section; 460 switch (symb->st_shndx) { 461 case ELF::SHN_COMMON: // Fall through. 462 // Undefined symbols have no address yet. 463 case ELF::SHN_UNDEF: 464 Result = UnknownAddressOrSize; 465 return object_error::success; 466 case ELF::SHN_ABS: 467 Result = reinterpret_cast<uintptr_t>(base()+symb->st_value); 468 return object_error::success; 469 default: Section = getSection(symb->st_shndx); 470 } 471 const uint8_t* addr = base(); 472 if (Section) 473 addr += Section->sh_offset; 474 switch (symb->getType()) { 475 case ELF::STT_SECTION: 476 Result = reinterpret_cast<uintptr_t>(addr); 477 return object_error::success; 478 case ELF::STT_FUNC: // Fall through. 479 case ELF::STT_OBJECT: // Fall through. 480 case ELF::STT_NOTYPE: 481 addr += symb->st_value; 482 Result = reinterpret_cast<uintptr_t>(addr); 483 return object_error::success; 484 default: 485 Result = UnknownAddressOrSize; 486 return object_error::success; 487 } 488 } 489 490 template<support::endianness target_endianness, bool is64Bits> 491 error_code ELFObjectFile<target_endianness, is64Bits> 492 ::getSymbolSize(DataRefImpl Symb, 493 uint64_t &Result) const { 494 validateSymbol(Symb); 495 const Elf_Sym *symb = getSymbol(Symb); 496 if (symb->st_size == 0) 497 Result = UnknownAddressOrSize; 498 Result = symb->st_size; 499 return object_error::success; 500 } 501 502 template<support::endianness target_endianness, bool is64Bits> 503 error_code ELFObjectFile<target_endianness, is64Bits> 504 ::getSymbolNMTypeChar(DataRefImpl Symb, 505 char &Result) const { 506 validateSymbol(Symb); 507 const Elf_Sym *symb = getSymbol(Symb); 508 const Elf_Shdr *Section = getSection(symb->st_shndx); 509 510 char ret = '?'; 511 512 if (Section) { 513 switch (Section->sh_type) { 514 case ELF::SHT_PROGBITS: 515 case ELF::SHT_DYNAMIC: 516 switch (Section->sh_flags) { 517 case (ELF::SHF_ALLOC | ELF::SHF_EXECINSTR): 518 ret = 't'; break; 519 case (ELF::SHF_ALLOC | ELF::SHF_WRITE): 520 ret = 'd'; break; 521 case ELF::SHF_ALLOC: 522 case (ELF::SHF_ALLOC | ELF::SHF_MERGE): 523 case (ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::SHF_STRINGS): 524 ret = 'r'; break; 525 } 526 break; 527 case ELF::SHT_NOBITS: ret = 'b'; 528 } 529 } 530 531 switch (symb->st_shndx) { 532 case ELF::SHN_UNDEF: 533 if (ret == '?') 534 ret = 'U'; 535 break; 536 case ELF::SHN_ABS: ret = 'a'; break; 537 case ELF::SHN_COMMON: ret = 'c'; break; 538 } 539 540 switch (symb->getBinding()) { 541 case ELF::STB_GLOBAL: ret = ::toupper(ret); break; 542 case ELF::STB_WEAK: 543 if (symb->st_shndx == ELF::SHN_UNDEF) 544 ret = 'w'; 545 else 546 if (symb->getType() == ELF::STT_OBJECT) 547 ret = 'V'; 548 else 549 ret = 'W'; 550 } 551 552 if (ret == '?' && symb->getType() == ELF::STT_SECTION) { 553 StringRef name; 554 if (error_code ec = getSymbolName(Symb, name)) 555 return ec; 556 Result = StringSwitch<char>(name) 557 .StartsWith(".debug", 'N') 558 .StartsWith(".note", 'n') 559 .Default('?'); 560 return object_error::success; 561 } 562 563 Result = ret; 564 return object_error::success; 565 } 566 567 template<support::endianness target_endianness, bool is64Bits> 568 error_code ELFObjectFile<target_endianness, is64Bits> 569 ::getSymbolType(DataRefImpl Symb, 570 SymbolRef::SymbolType &Result) const { 571 validateSymbol(Symb); 572 const Elf_Sym *symb = getSymbol(Symb); 573 574 if (symb->st_shndx == ELF::SHN_UNDEF) { 575 Result = SymbolRef::ST_External; 576 return object_error::success; 577 } 578 579 switch (symb->getType()) { 580 case ELF::STT_FUNC: 581 Result = SymbolRef::ST_Function; 582 break; 583 case ELF::STT_OBJECT: 584 Result = SymbolRef::ST_Data; 585 break; 586 default: 587 Result = SymbolRef::ST_Other; 588 break; 589 } 590 return object_error::success; 591 } 592 593 template<support::endianness target_endianness, bool is64Bits> 594 error_code ELFObjectFile<target_endianness, is64Bits> 595 ::isSymbolGlobal(DataRefImpl Symb, 596 bool &Result) const { 597 validateSymbol(Symb); 598 const Elf_Sym *symb = getSymbol(Symb); 599 600 Result = symb->getBinding() == ELF::STB_GLOBAL; 601 return object_error::success; 602 } 603 604 template<support::endianness target_endianness, bool is64Bits> 605 error_code ELFObjectFile<target_endianness, is64Bits> 606 ::isSymbolInternal(DataRefImpl Symb, 607 bool &Result) const { 608 validateSymbol(Symb); 609 const Elf_Sym *symb = getSymbol(Symb); 610 611 if ( symb->getType() == ELF::STT_FILE 612 || symb->getType() == ELF::STT_SECTION) 613 Result = true; 614 Result = false; 615 return object_error::success; 616 } 617 618 template<support::endianness target_endianness, bool is64Bits> 619 error_code ELFObjectFile<target_endianness, is64Bits> 620 ::getSectionNext(DataRefImpl Sec, SectionRef &Result) const { 621 const uint8_t *sec = reinterpret_cast<const uint8_t *>(Sec.p); 622 sec += Header->e_shentsize; 623 Sec.p = reinterpret_cast<intptr_t>(sec); 624 Result = SectionRef(Sec, this); 625 return object_error::success; 626 } 627 628 template<support::endianness target_endianness, bool is64Bits> 629 error_code ELFObjectFile<target_endianness, is64Bits> 630 ::getSectionName(DataRefImpl Sec, 631 StringRef &Result) const { 632 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 633 Result = StringRef(getString(dot_shstrtab_sec, sec->sh_name)); 634 return object_error::success; 635 } 636 637 template<support::endianness target_endianness, bool is64Bits> 638 error_code ELFObjectFile<target_endianness, is64Bits> 639 ::getSectionAddress(DataRefImpl Sec, 640 uint64_t &Result) const { 641 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 642 Result = sec->sh_addr; 643 return object_error::success; 644 } 645 646 template<support::endianness target_endianness, bool is64Bits> 647 error_code ELFObjectFile<target_endianness, is64Bits> 648 ::getSectionSize(DataRefImpl Sec, 649 uint64_t &Result) const { 650 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 651 Result = sec->sh_size; 652 return object_error::success; 653 } 654 655 template<support::endianness target_endianness, bool is64Bits> 656 error_code ELFObjectFile<target_endianness, is64Bits> 657 ::getSectionContents(DataRefImpl Sec, 658 StringRef &Result) const { 659 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 660 const char *start = (const char*)base() + sec->sh_offset; 661 Result = StringRef(start, sec->sh_size); 662 return object_error::success; 663 } 664 665 template<support::endianness target_endianness, bool is64Bits> 666 error_code ELFObjectFile<target_endianness, is64Bits> 667 ::isSectionText(DataRefImpl Sec, 668 bool &Result) const { 669 const Elf_Shdr *sec = reinterpret_cast<const Elf_Shdr *>(Sec.p); 670 if (sec->sh_flags & ELF::SHF_EXECINSTR) 671 Result = true; 672 else 673 Result = false; 674 return object_error::success; 675 } 676 677 template<support::endianness target_endianness, bool is64Bits> 678 error_code ELFObjectFile<target_endianness, is64Bits> 679 ::sectionContainsSymbol(DataRefImpl Sec, 680 DataRefImpl Symb, 681 bool &Result) const { 682 // FIXME: Unimplemented. 683 Result = false; 684 return object_error::success; 685 } 686 687 // Relocations 688 template<support::endianness target_endianness, bool is64Bits> 689 error_code ELFObjectFile<target_endianness, is64Bits> 690 ::getRelocationNext(DataRefImpl Rel, 691 RelocationRef &Result) const { 692 const Elf_Shdr *RelocationTableSection = RelocationTableSections[Rel.d.b]; 693 694 // Check to see if we are at the end of this relocation table. 695 if (++Rel.d.a >= RelocationTableSection->getEntityCount()) { 696 // We are at the end. If there are other relocation tables, jump to them. 697 Rel.d.a = 0; 698 // Otherwise return the terminator. 699 if (++Rel.d.b >= SymbolTableSections.size()) { 700 Rel.d.a = std::numeric_limits<uint32_t>::max(); 701 Rel.d.b = std::numeric_limits<uint32_t>::max(); 702 } 703 } 704 705 Result = RelocationRef(Rel, this); 706 return object_error::success; 707 } 708 709 template<support::endianness target_endianness, bool is64Bits> 710 error_code ELFObjectFile<target_endianness, is64Bits> 711 ::getRelocationSymbol(DataRefImpl Rel, 712 SymbolRef &Result) const { 713 uint32_t symbolIdx; 714 const Elf_Shdr *sec = RelocationTableSections[Rel.d.b]; 715 switch (sec->sh_type) { 716 default : 717 report_fatal_error("Invalid section type in Rel!"); 718 case ELF::SHT_REL : { 719 symbolIdx = getRel(Rel)->getSymbol(); 720 break; 721 } 722 case ELF::SHT_RELA : { 723 symbolIdx = getRela(Rel)->getSymbol(); 724 break; 725 } 726 } 727 DataRefImpl SymbolData; 728 IndexMap_t::const_iterator it = SymbolTableSectionsIndexMap.find(sec->sh_link); 729 if (it == SymbolTableSectionsIndexMap.end()) 730 report_fatal_error("Relocation symbol table not found!"); 731 SymbolData.d.a = symbolIdx; 732 SymbolData.d.b = it->second; 733 Result = SymbolRef(SymbolData, this); 734 return object_error::success; 735 } 736 737 template<support::endianness target_endianness, bool is64Bits> 738 error_code ELFObjectFile<target_endianness, is64Bits> 739 ::getRelocationAddress(DataRefImpl Rel, 740 uint64_t &Result) const { 741 uint64_t offset; 742 const Elf_Shdr *sec = RelocationTableSections[Rel.d.b]; 743 switch (sec->sh_type) { 744 default : 745 report_fatal_error("Invalid section type in Rel!"); 746 case ELF::SHT_REL : { 747 offset = getRel(Rel)->r_offset; 748 break; 749 } 750 case ELF::SHT_RELA : { 751 offset = getRela(Rel)->r_offset; 752 break; 753 } 754 } 755 756 const Elf_Shdr *secAddr = getSection(sec->sh_info); 757 Result = offset + reinterpret_cast<uintptr_t>(base() + secAddr->sh_offset); 758 return object_error::success; 759 } 760 761 template<support::endianness target_endianness, bool is64Bits> 762 error_code ELFObjectFile<target_endianness, is64Bits> 763 ::getRelocationType(DataRefImpl Rel, 764 uint32_t &Result) const { 765 const Elf_Shdr *sec = RelocationTableSections[Rel.d.b]; 766 switch (sec->sh_type) { 767 default : 768 report_fatal_error("Invalid section type in Rel!"); 769 case ELF::SHT_REL : { 770 Result = getRel(Rel)->getType(); 771 break; 772 } 773 case ELF::SHT_RELA : { 774 Result = getRela(Rel)->getType(); 775 break; 776 } 777 } 778 return object_error::success; 779 } 780 781 template<support::endianness target_endianness, bool is64Bits> 782 error_code ELFObjectFile<target_endianness, is64Bits> 783 ::getRelocationAdditionalInfo(DataRefImpl Rel, 784 int64_t &Result) const { 785 const Elf_Shdr *sec = RelocationTableSections[Rel.d.b]; 786 switch (sec->sh_type) { 787 default : 788 report_fatal_error("Invalid section type in Rel!"); 789 case ELF::SHT_REL : { 790 Result = 0; 791 return object_error::success; 792 } 793 case ELF::SHT_RELA : { 794 Result = getRela(Rel)->r_addend; 795 return object_error::success; 796 } 797 } 798 } 799 800 801 802 template<support::endianness target_endianness, bool is64Bits> 803 ELFObjectFile<target_endianness, is64Bits>::ELFObjectFile(MemoryBuffer *Object 804 , error_code &ec) 805 : ObjectFile(Binary::isELF, Object, ec) 806 , SectionHeaderTable(0) 807 , dot_shstrtab_sec(0) 808 , dot_strtab_sec(0) { 809 Header = reinterpret_cast<const Elf_Ehdr *>(base()); 810 811 if (Header->e_shoff == 0) 812 return; 813 814 SectionHeaderTable = 815 reinterpret_cast<const Elf_Shdr *>(base() + Header->e_shoff); 816 uint32_t SectionTableSize = Header->e_shnum * Header->e_shentsize; 817 if (!( (const uint8_t *)SectionHeaderTable + SectionTableSize 818 <= base() + Data->getBufferSize())) 819 // FIXME: Proper error handling. 820 report_fatal_error("Section table goes past end of file!"); 821 822 823 // To find the symbol tables we walk the section table to find SHT_STMTAB. 824 const Elf_Shdr* sh = 825 reinterpret_cast<const Elf_Shdr*>(SectionHeaderTable); 826 for (unsigned i = 0; i < Header->e_shnum; ++i) { 827 if (sh->sh_type == ELF::SHT_SYMTAB) { 828 SymbolTableSectionsIndexMap[i] = SymbolTableSections.size(); 829 SymbolTableSections.push_back(sh); 830 } 831 if (sh->sh_type == ELF::SHT_REL || sh->sh_type == ELF::SHT_RELA) { 832 RelocationTableSections.push_back(sh); 833 } 834 ++sh; 835 } 836 837 // Get string table sections. 838 dot_shstrtab_sec = getSection(Header->e_shstrndx); 839 if (dot_shstrtab_sec) { 840 // Verify that the last byte in the string table in a null. 841 if (((const char*)base() + dot_shstrtab_sec->sh_offset) 842 [dot_shstrtab_sec->sh_size - 1] != 0) 843 // FIXME: Proper error handling. 844 report_fatal_error("String table must end with a null terminator!"); 845 } 846 847 // Merge this into the above loop. 848 for (const char *i = reinterpret_cast<const char *>(SectionHeaderTable), 849 *e = i + Header->e_shnum * Header->e_shentsize; 850 i != e; i += Header->e_shentsize) { 851 const Elf_Shdr *sh = reinterpret_cast<const Elf_Shdr*>(i); 852 if (sh->sh_type == ELF::SHT_STRTAB) { 853 StringRef SectionName(getString(dot_shstrtab_sec, sh->sh_name)); 854 if (SectionName == ".strtab") { 855 if (dot_strtab_sec != 0) 856 // FIXME: Proper error handling. 857 report_fatal_error("Already found section named .strtab!"); 858 dot_strtab_sec = sh; 859 const char *dot_strtab = (const char*)base() + sh->sh_offset; 860 if (dot_strtab[sh->sh_size - 1] != 0) 861 // FIXME: Proper error handling. 862 report_fatal_error("String table must end with a null terminator!"); 863 } 864 } 865 } 866 } 867 868 template<support::endianness target_endianness, bool is64Bits> 869 ObjectFile::symbol_iterator ELFObjectFile<target_endianness, is64Bits> 870 ::begin_symbols() const { 871 DataRefImpl SymbolData; 872 memset(&SymbolData, 0, sizeof(SymbolData)); 873 if (SymbolTableSections.size() == 0) { 874 SymbolData.d.a = std::numeric_limits<uint32_t>::max(); 875 SymbolData.d.b = std::numeric_limits<uint32_t>::max(); 876 } else { 877 SymbolData.d.a = 1; // The 0th symbol in ELF is fake. 878 SymbolData.d.b = 0; 879 } 880 return symbol_iterator(SymbolRef(SymbolData, this)); 881 } 882 883 template<support::endianness target_endianness, bool is64Bits> 884 ObjectFile::symbol_iterator ELFObjectFile<target_endianness, is64Bits> 885 ::end_symbols() const { 886 DataRefImpl SymbolData; 887 memset(&SymbolData, 0, sizeof(SymbolData)); 888 SymbolData.d.a = std::numeric_limits<uint32_t>::max(); 889 SymbolData.d.b = std::numeric_limits<uint32_t>::max(); 890 return symbol_iterator(SymbolRef(SymbolData, this)); 891 } 892 893 template<support::endianness target_endianness, bool is64Bits> 894 ObjectFile::section_iterator ELFObjectFile<target_endianness, is64Bits> 895 ::begin_sections() const { 896 DataRefImpl ret; 897 memset(&ret, 0, sizeof(DataRefImpl)); 898 ret.p = reinterpret_cast<intptr_t>(base() + Header->e_shoff); 899 return section_iterator(SectionRef(ret, this)); 900 } 901 902 template<support::endianness target_endianness, bool is64Bits> 903 ObjectFile::section_iterator ELFObjectFile<target_endianness, is64Bits> 904 ::end_sections() const { 905 DataRefImpl ret; 906 memset(&ret, 0, sizeof(DataRefImpl)); 907 ret.p = reinterpret_cast<intptr_t>(base() 908 + Header->e_shoff 909 + (Header->e_shentsize * Header->e_shnum)); 910 return section_iterator(SectionRef(ret, this)); 911 } 912 913 template<support::endianness target_endianness, bool is64Bits> 914 ObjectFile::relocation_iterator ELFObjectFile<target_endianness, is64Bits> 915 ::begin_relocations() const { 916 DataRefImpl RelData; 917 memset(&RelData, 0, sizeof(RelData)); 918 if (RelocationTableSections.size() == 0) { 919 RelData.d.a = std::numeric_limits<uint32_t>::max(); 920 RelData.d.b = std::numeric_limits<uint32_t>::max(); 921 } else { 922 RelData.d.a = 0; 923 RelData.d.b = 0; 924 } 925 return relocation_iterator(RelocationRef(RelData, this)); 926 } 927 928 template<support::endianness target_endianness, bool is64Bits> 929 ObjectFile::relocation_iterator ELFObjectFile<target_endianness, is64Bits> 930 ::end_relocations() const { 931 DataRefImpl RelData; 932 memset(&RelData, 0, sizeof(RelData)); 933 RelData.d.a = std::numeric_limits<uint32_t>::max(); 934 RelData.d.b = std::numeric_limits<uint32_t>::max(); 935 return relocation_iterator(RelocationRef(RelData, this)); 936 } 937 938 template<support::endianness target_endianness, bool is64Bits> 939 uint8_t ELFObjectFile<target_endianness, is64Bits>::getBytesInAddress() const { 940 return is64Bits ? 8 : 4; 941 } 942 943 template<support::endianness target_endianness, bool is64Bits> 944 StringRef ELFObjectFile<target_endianness, is64Bits> 945 ::getFileFormatName() const { 946 switch(Header->e_ident[ELF::EI_CLASS]) { 947 case ELF::ELFCLASS32: 948 switch(Header->e_machine) { 949 case ELF::EM_386: 950 return "ELF32-i386"; 951 case ELF::EM_X86_64: 952 return "ELF32-x86-64"; 953 case ELF::EM_ARM: 954 return "ELF32-arm"; 955 default: 956 return "ELF32-unknown"; 957 } 958 case ELF::ELFCLASS64: 959 switch(Header->e_machine) { 960 case ELF::EM_386: 961 return "ELF64-i386"; 962 case ELF::EM_X86_64: 963 return "ELF64-x86-64"; 964 default: 965 return "ELF64-unknown"; 966 } 967 default: 968 // FIXME: Proper error handling. 969 report_fatal_error("Invalid ELFCLASS!"); 970 } 971 } 972 973 template<support::endianness target_endianness, bool is64Bits> 974 unsigned ELFObjectFile<target_endianness, is64Bits>::getArch() const { 975 switch(Header->e_machine) { 976 case ELF::EM_386: 977 return Triple::x86; 978 case ELF::EM_X86_64: 979 return Triple::x86_64; 980 case ELF::EM_ARM: 981 return Triple::arm; 982 default: 983 return Triple::UnknownArch; 984 } 985 } 986 987 template<support::endianness target_endianness, bool is64Bits> 988 template<typename T> 989 inline const T * 990 ELFObjectFile<target_endianness, is64Bits>::getEntry(DataRefImpl Entry, 991 Sections_t Sections) const { 992 const Elf_Shdr *sec = Sections[Entry.d.b]; 993 return reinterpret_cast<const T *>( 994 base() 995 + sec->sh_offset 996 + (Entry.d.a * sec->sh_entsize)); 997 } 998 999 template<support::endianness target_endianness, bool is64Bits> 1000 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Sym * 1001 ELFObjectFile<target_endianness, is64Bits>::getSymbol(DataRefImpl Symb) const { 1002 return getEntry<Elf_Sym>(Symb, SymbolTableSections); 1003 } 1004 1005 template<support::endianness target_endianness, bool is64Bits> 1006 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Rel * 1007 ELFObjectFile<target_endianness, is64Bits>::getRel(DataRefImpl Rel) const { 1008 return getEntry<Elf_Rel>(Rel, RelocationTableSections); 1009 } 1010 1011 template<support::endianness target_endianness, bool is64Bits> 1012 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Rela * 1013 ELFObjectFile<target_endianness, is64Bits>::getRela(DataRefImpl Rela) const { 1014 return getEntry<Elf_Rela>(Rela, RelocationTableSections); 1015 } 1016 1017 template<support::endianness target_endianness, bool is64Bits> 1018 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Shdr * 1019 ELFObjectFile<target_endianness, is64Bits>::getSection(DataRefImpl Symb) const { 1020 const Elf_Shdr *sec = getSection(Symb.d.b); 1021 if (sec->sh_type != ELF::SHT_SYMTAB) 1022 // FIXME: Proper error handling. 1023 report_fatal_error("Invalid symbol table section!"); 1024 return sec; 1025 } 1026 1027 template<support::endianness target_endianness, bool is64Bits> 1028 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Shdr * 1029 ELFObjectFile<target_endianness, is64Bits>::getSection(uint16_t index) const { 1030 if (index == 0 || index >= ELF::SHN_LORESERVE) 1031 return 0; 1032 if (!SectionHeaderTable || index >= Header->e_shnum) 1033 // FIXME: Proper error handling. 1034 report_fatal_error("Invalid section index!"); 1035 1036 return reinterpret_cast<const Elf_Shdr *>( 1037 reinterpret_cast<const char *>(SectionHeaderTable) 1038 + (index * Header->e_shentsize)); 1039 } 1040 1041 template<support::endianness target_endianness, bool is64Bits> 1042 const char *ELFObjectFile<target_endianness, is64Bits> 1043 ::getString(uint16_t section, 1044 ELF::Elf32_Word offset) const { 1045 return getString(getSection(section), offset); 1046 } 1047 1048 template<support::endianness target_endianness, bool is64Bits> 1049 const char *ELFObjectFile<target_endianness, is64Bits> 1050 ::getString(const Elf_Shdr *section, 1051 ELF::Elf32_Word offset) const { 1052 assert(section && section->sh_type == ELF::SHT_STRTAB && "Invalid section!"); 1053 if (offset >= section->sh_size) 1054 // FIXME: Proper error handling. 1055 report_fatal_error("Symbol name offset outside of string table!"); 1056 return (const char *)base() + section->sh_offset + offset; 1057 } 1058 1059 // EI_CLASS, EI_DATA. 1060 static std::pair<unsigned char, unsigned char> 1061 getElfArchType(MemoryBuffer *Object) { 1062 if (Object->getBufferSize() < ELF::EI_NIDENT) 1063 return std::make_pair((uint8_t)ELF::ELFCLASSNONE,(uint8_t)ELF::ELFDATANONE); 1064 return std::make_pair( (uint8_t)Object->getBufferStart()[ELF::EI_CLASS] 1065 , (uint8_t)Object->getBufferStart()[ELF::EI_DATA]); 1066 } 1067 1068 namespace llvm { 1069 1070 ObjectFile *ObjectFile::createELFObjectFile(MemoryBuffer *Object) { 1071 std::pair<unsigned char, unsigned char> Ident = getElfArchType(Object); 1072 error_code ec; 1073 if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB) 1074 return new ELFObjectFile<support::little, false>(Object, ec); 1075 else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB) 1076 return new ELFObjectFile<support::big, false>(Object, ec); 1077 else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) 1078 return new ELFObjectFile<support::little, true>(Object, ec); 1079 else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB) 1080 return new ELFObjectFile<support::big, true>(Object, ec); 1081 // FIXME: Proper error handling. 1082 report_fatal_error("Not an ELF object file!"); 1083 } 1084 1085 } // end namespace llvm 1086