1 //===- ELF.h - ELF object file implementation -------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the ELFFile template class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_OBJECT_ELF_H
15 #define LLVM_OBJECT_ELF_H
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/Object/ELFTypes.h"
19 #include "llvm/Support/MemoryBuffer.h"
24 StringRef getELFRelocationTypeName(uint32_t Machine, uint32_t Type);
26 // Subclasses of ELFFile may need this for template instantiation
27 inline std::pair<unsigned char, unsigned char>
28 getElfArchType(StringRef Object) {
29 if (Object.size() < ELF::EI_NIDENT)
30 return std::make_pair((uint8_t)ELF::ELFCLASSNONE,
31 (uint8_t)ELF::ELFDATANONE);
32 return std::make_pair((uint8_t)Object[ELF::EI_CLASS],
33 (uint8_t)Object[ELF::EI_DATA]);
39 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
40 typedef typename std::conditional<ELFT::Is64Bits,
41 uint64_t, uint32_t>::type uintX_t;
43 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
44 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
45 typedef Elf_Sym_Impl<ELFT> Elf_Sym;
46 typedef Elf_Dyn_Impl<ELFT> Elf_Dyn;
47 typedef Elf_Phdr_Impl<ELFT> Elf_Phdr;
48 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
49 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
50 typedef Elf_Verdef_Impl<ELFT> Elf_Verdef;
51 typedef Elf_Verdaux_Impl<ELFT> Elf_Verdaux;
52 typedef Elf_Verneed_Impl<ELFT> Elf_Verneed;
53 typedef Elf_Vernaux_Impl<ELFT> Elf_Vernaux;
54 typedef Elf_Versym_Impl<ELFT> Elf_Versym;
55 typedef Elf_Hash_Impl<ELFT> Elf_Hash;
56 typedef iterator_range<const Elf_Dyn *> Elf_Dyn_Range;
57 typedef iterator_range<const Elf_Shdr *> Elf_Shdr_Range;
58 typedef iterator_range<const Elf_Sym *> Elf_Sym_Range;
60 const uint8_t *base() const {
61 return reinterpret_cast<const uint8_t *>(Buf.data());
68 const Elf_Ehdr *Header;
69 const Elf_Shdr *SectionHeaderTable = nullptr;
70 StringRef DotShstrtab; // Section header string table.
74 const T *getEntry(uint32_t Section, uint32_t Entry) const;
76 const T *getEntry(const Elf_Shdr *Section, uint32_t Entry) const;
78 ErrorOr<StringRef> getStringTable(const Elf_Shdr *Section) const;
79 ErrorOr<StringRef> getStringTableForSymtab(const Elf_Shdr &Section) const;
81 ErrorOr<ArrayRef<Elf_Word>> getSHNDXTable(const Elf_Shdr &Section) const;
83 void VerifyStrTab(const Elf_Shdr *sh) const;
85 StringRef getRelocationTypeName(uint32_t Type) const;
86 void getRelocationTypeName(uint32_t Type,
87 SmallVectorImpl<char> &Result) const;
89 /// \brief Get the symbol for a given relocation.
90 const Elf_Sym *getRelocationSymbol(const Elf_Rel *Rel,
91 const Elf_Shdr *SymTab) const;
93 ELFFile(StringRef Object, std::error_code &EC);
95 bool isMipsELF64() const {
96 return Header->e_machine == ELF::EM_MIPS &&
97 Header->getFileClass() == ELF::ELFCLASS64;
100 bool isMips64EL() const {
101 return Header->e_machine == ELF::EM_MIPS &&
102 Header->getFileClass() == ELF::ELFCLASS64 &&
103 Header->getDataEncoding() == ELF::ELFDATA2LSB;
106 ErrorOr<const Elf_Dyn *> dynamic_table_begin(const Elf_Phdr *Phdr) const;
107 ErrorOr<const Elf_Dyn *> dynamic_table_end(const Elf_Phdr *Phdr) const;
108 ErrorOr<Elf_Dyn_Range> dynamic_table(const Elf_Phdr *Phdr) const {
109 ErrorOr<const Elf_Dyn *> Begin = dynamic_table_begin(Phdr);
110 if (std::error_code EC = Begin.getError())
112 ErrorOr<const Elf_Dyn *> End = dynamic_table_end(Phdr);
113 if (std::error_code EC = End.getError())
115 return make_range(*Begin, *End);
118 const Elf_Shdr *section_begin() const;
119 const Elf_Shdr *section_end() const;
120 Elf_Shdr_Range sections() const {
121 return make_range(section_begin(), section_end());
124 const Elf_Sym *symbol_begin(const Elf_Shdr *Sec) const {
127 if (Sec->sh_entsize != sizeof(Elf_Sym))
128 report_fatal_error("Invalid symbol size");
129 return reinterpret_cast<const Elf_Sym *>(base() + Sec->sh_offset);
131 const Elf_Sym *symbol_end(const Elf_Shdr *Sec) const {
134 uint64_t Size = Sec->sh_size;
135 if (Size % sizeof(Elf_Sym))
136 report_fatal_error("Invalid symbol table size");
137 return symbol_begin(Sec) + Size / sizeof(Elf_Sym);
139 Elf_Sym_Range symbols(const Elf_Shdr *Sec) const {
140 return make_range(symbol_begin(Sec), symbol_end(Sec));
143 typedef iterator_range<const Elf_Rela *> Elf_Rela_Range;
145 const Elf_Rela *rela_begin(const Elf_Shdr *sec) const {
146 if (sec->sh_entsize != sizeof(Elf_Rela))
147 report_fatal_error("Invalid relocation entry size");
148 return reinterpret_cast<const Elf_Rela *>(base() + sec->sh_offset);
151 const Elf_Rela *rela_end(const Elf_Shdr *sec) const {
152 uint64_t Size = sec->sh_size;
153 if (Size % sizeof(Elf_Rela))
154 report_fatal_error("Invalid relocation table size");
155 return rela_begin(sec) + Size / sizeof(Elf_Rela);
158 Elf_Rela_Range relas(const Elf_Shdr *Sec) const {
159 return make_range(rela_begin(Sec), rela_end(Sec));
162 const Elf_Rel *rel_begin(const Elf_Shdr *sec) const {
163 if (sec->sh_entsize != sizeof(Elf_Rel))
164 report_fatal_error("Invalid relocation entry size");
165 return reinterpret_cast<const Elf_Rel *>(base() + sec->sh_offset);
168 const Elf_Rel *rel_end(const Elf_Shdr *sec) const {
169 uint64_t Size = sec->sh_size;
170 if (Size % sizeof(Elf_Rel))
171 report_fatal_error("Invalid relocation table size");
172 return rel_begin(sec) + Size / sizeof(Elf_Rel);
175 typedef iterator_range<const Elf_Rel *> Elf_Rel_Range;
176 Elf_Rel_Range rels(const Elf_Shdr *Sec) const {
177 return make_range(rel_begin(Sec), rel_end(Sec));
180 /// \brief Iterate over program header table.
181 const Elf_Phdr *program_header_begin() const {
182 if (Header->e_phnum && Header->e_phentsize != sizeof(Elf_Phdr))
183 report_fatal_error("Invalid program header size");
184 return reinterpret_cast<const Elf_Phdr *>(base() + Header->e_phoff);
187 const Elf_Phdr *program_header_end() const {
188 return program_header_begin() + Header->e_phnum;
191 typedef iterator_range<const Elf_Phdr *> Elf_Phdr_Range;
193 const Elf_Phdr_Range program_headers() const {
194 return make_range(program_header_begin(), program_header_end());
197 uint64_t getNumSections() const;
198 uintX_t getStringTableIndex() const;
199 uint32_t getExtendedSymbolTableIndex(const Elf_Sym *Sym,
200 const Elf_Shdr *SymTab,
201 ArrayRef<Elf_Word> ShndxTable) const;
202 const Elf_Ehdr *getHeader() const { return Header; }
203 ErrorOr<const Elf_Shdr *> getSection(const Elf_Sym *Sym,
204 const Elf_Shdr *SymTab,
205 ArrayRef<Elf_Word> ShndxTable) const;
206 ErrorOr<const Elf_Shdr *> getSection(uint32_t Index) const;
208 const Elf_Sym *getSymbol(const Elf_Shdr *Sec, uint32_t Index) const {
209 return &*(symbol_begin(Sec) + Index);
212 ErrorOr<StringRef> getSectionName(const Elf_Shdr *Section) const;
213 ErrorOr<ArrayRef<uint8_t> > getSectionContents(const Elf_Shdr *Sec) const;
216 typedef ELFFile<ELFType<support::little, false>> ELF32LEFile;
217 typedef ELFFile<ELFType<support::little, true>> ELF64LEFile;
218 typedef ELFFile<ELFType<support::big, false>> ELF32BEFile;
219 typedef ELFFile<ELFType<support::big, true>> ELF64BEFile;
221 template <class ELFT>
222 uint32_t ELFFile<ELFT>::getExtendedSymbolTableIndex(
223 const Elf_Sym *Sym, const Elf_Shdr *SymTab,
224 ArrayRef<Elf_Word> ShndxTable) const {
225 assert(Sym->st_shndx == ELF::SHN_XINDEX);
226 unsigned Index = Sym - symbol_begin(SymTab);
228 // The size of the table was checked in getSHNDXTable.
229 return ShndxTable[Index];
232 template <class ELFT>
233 ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
234 ELFFile<ELFT>::getSection(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
235 ArrayRef<Elf_Word> ShndxTable) const {
236 uint32_t Index = Sym->st_shndx;
237 if (Index == ELF::SHN_XINDEX)
238 return getSection(getExtendedSymbolTableIndex(Sym, SymTab, ShndxTable));
240 if (Index == ELF::SHN_UNDEF || Index >= ELF::SHN_LORESERVE)
242 return getSection(Sym->st_shndx);
245 template <class ELFT>
246 ErrorOr<ArrayRef<uint8_t> >
247 ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const {
248 if (Sec->sh_offset + Sec->sh_size > Buf.size())
249 return object_error::parse_failed;
250 const uint8_t *Start = base() + Sec->sh_offset;
251 return makeArrayRef(Start, Sec->sh_size);
254 template <class ELFT>
255 StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const {
256 return getELFRelocationTypeName(Header->e_machine, Type);
259 template <class ELFT>
260 void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
261 SmallVectorImpl<char> &Result) const {
262 if (!isMipsELF64()) {
263 StringRef Name = getRelocationTypeName(Type);
264 Result.append(Name.begin(), Name.end());
266 // The Mips N64 ABI allows up to three operations to be specified per
267 // relocation record. Unfortunately there's no easy way to test for the
268 // presence of N64 ELFs as they have no special flag that identifies them
269 // as being N64. We can safely assume at the moment that all Mips
270 // ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough
271 // information to disambiguate between old vs new ABIs.
272 uint8_t Type1 = (Type >> 0) & 0xFF;
273 uint8_t Type2 = (Type >> 8) & 0xFF;
274 uint8_t Type3 = (Type >> 16) & 0xFF;
276 // Concat all three relocation type names.
277 StringRef Name = getRelocationTypeName(Type1);
278 Result.append(Name.begin(), Name.end());
280 Name = getRelocationTypeName(Type2);
281 Result.append(1, '/');
282 Result.append(Name.begin(), Name.end());
284 Name = getRelocationTypeName(Type3);
285 Result.append(1, '/');
286 Result.append(Name.begin(), Name.end());
290 template <class ELFT>
291 const typename ELFFile<ELFT>::Elf_Sym *
292 ELFFile<ELFT>::getRelocationSymbol(const Elf_Rel *Rel,
293 const Elf_Shdr *SymTab) const {
294 uint32_t Index = Rel->getSymbol(isMips64EL());
297 return getEntry<Elf_Sym>(SymTab, Index);
300 template <class ELFT>
301 uint64_t ELFFile<ELFT>::getNumSections() const {
302 assert(Header && "Header not initialized!");
303 if (Header->e_shnum == ELF::SHN_UNDEF && Header->e_shoff > 0) {
304 assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
305 return SectionHeaderTable->sh_size;
307 return Header->e_shnum;
310 template <class ELFT>
311 typename ELFFile<ELFT>::uintX_t ELFFile<ELFT>::getStringTableIndex() const {
312 if (Header->e_shnum == ELF::SHN_UNDEF) {
313 if (Header->e_shstrndx == ELF::SHN_HIRESERVE)
314 return SectionHeaderTable->sh_link;
315 if (Header->e_shstrndx >= getNumSections())
318 return Header->e_shstrndx;
321 template <class ELFT>
322 ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
324 const uint64_t FileSize = Buf.size();
326 if (sizeof(Elf_Ehdr) > FileSize) {
328 EC = object_error::parse_failed;
332 Header = reinterpret_cast<const Elf_Ehdr *>(base());
334 if (Header->e_shoff == 0)
337 const uint64_t SectionTableOffset = Header->e_shoff;
339 if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize) {
340 // Section header table goes past end of file!
341 EC = object_error::parse_failed;
345 // The getNumSections() call below depends on SectionHeaderTable being set.
347 reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);
348 const uint64_t SectionTableSize = getNumSections() * Header->e_shentsize;
350 if (SectionTableOffset + SectionTableSize > FileSize) {
351 // Section table goes past end of file!
352 EC = object_error::parse_failed;
356 // Get string table sections.
357 uintX_t StringTableIndex = getStringTableIndex();
358 if (StringTableIndex) {
359 ErrorOr<const Elf_Shdr *> StrTabSecOrErr = getSection(StringTableIndex);
360 if ((EC = StrTabSecOrErr.getError()))
363 ErrorOr<StringRef> StringTableOrErr = getStringTable(*StrTabSecOrErr);
364 if ((EC = StringTableOrErr.getError()))
366 DotShstrtab = *StringTableOrErr;
369 EC = std::error_code();
372 template <class ELFT>
373 static bool compareAddr(uint64_t VAddr, const Elf_Phdr_Impl<ELFT> *Phdr) {
374 return VAddr < Phdr->p_vaddr;
377 template <class ELFT>
378 const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_begin() const {
379 if (Header->e_shentsize != sizeof(Elf_Shdr))
381 "Invalid section header entry size (e_shentsize) in ELF header");
382 return reinterpret_cast<const Elf_Shdr *>(base() + Header->e_shoff);
385 template <class ELFT>
386 const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_end() const {
387 return section_begin() + getNumSections();
390 template <class ELFT>
391 ErrorOr<const typename ELFFile<ELFT>::Elf_Dyn *>
392 ELFFile<ELFT>::dynamic_table_begin(const Elf_Phdr *Phdr) const {
395 assert(Phdr->p_type == ELF::PT_DYNAMIC && "Got the wrong program header");
396 uintX_t Offset = Phdr->p_offset;
397 if (Offset > Buf.size())
398 return object_error::parse_failed;
399 return reinterpret_cast<const Elf_Dyn *>(base() + Offset);
402 template <class ELFT>
403 ErrorOr<const typename ELFFile<ELFT>::Elf_Dyn *>
404 ELFFile<ELFT>::dynamic_table_end(const Elf_Phdr *Phdr) const {
407 assert(Phdr->p_type == ELF::PT_DYNAMIC && "Got the wrong program header");
408 uintX_t Size = Phdr->p_filesz;
409 if (Size % sizeof(Elf_Dyn))
410 return object_error::elf_invalid_dynamic_table_size;
411 // FIKME: Check for overflow?
412 uintX_t End = Phdr->p_offset + Size;
413 if (End > Buf.size())
414 return object_error::parse_failed;
415 return reinterpret_cast<const Elf_Dyn *>(base() + End);
418 template <class ELFT>
419 template <typename T>
420 const T *ELFFile<ELFT>::getEntry(uint32_t Section, uint32_t Entry) const {
421 ErrorOr<const Elf_Shdr *> Sec = getSection(Section);
422 if (std::error_code EC = Sec.getError())
423 report_fatal_error(EC.message());
424 return getEntry<T>(*Sec, Entry);
427 template <class ELFT>
428 template <typename T>
429 const T *ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
430 uint32_t Entry) const {
431 return reinterpret_cast<const T *>(base() + Section->sh_offset +
432 (Entry * Section->sh_entsize));
435 template <class ELFT>
436 ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
437 ELFFile<ELFT>::getSection(uint32_t Index) const {
438 assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
439 if (Index >= getNumSections())
440 return object_error::invalid_section_index;
442 return reinterpret_cast<const Elf_Shdr *>(
443 reinterpret_cast<const char *>(SectionHeaderTable) +
444 (Index * Header->e_shentsize));
447 template <class ELFT>
449 ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
450 if (Section->sh_type != ELF::SHT_STRTAB)
451 return object_error::parse_failed;
452 uint64_t Offset = Section->sh_offset;
453 uint64_t Size = Section->sh_size;
454 if (Offset + Size > Buf.size())
455 return object_error::parse_failed;
456 StringRef Data((const char *)base() + Section->sh_offset, Size);
457 if (Data[Size - 1] != '\0')
458 return object_error::string_table_non_null_end;
462 template <class ELFT>
463 ErrorOr<ArrayRef<typename ELFFile<ELFT>::Elf_Word>>
464 ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section) const {
465 assert(Section.sh_type == ELF::SHT_SYMTAB_SHNDX);
466 const Elf_Word *ShndxTableBegin =
467 reinterpret_cast<const Elf_Word *>(base() + Section.sh_offset);
468 uintX_t Size = Section.sh_size;
469 if (Size % sizeof(uint32_t))
470 return object_error::parse_failed;
471 uintX_t NumSymbols = Size / sizeof(uint32_t);
472 const Elf_Word *ShndxTableEnd = ShndxTableBegin + NumSymbols;
473 if (reinterpret_cast<const char *>(ShndxTableEnd) > Buf.end())
474 return object_error::parse_failed;
475 ErrorOr<const Elf_Shdr *> SymTableOrErr = getSection(Section.sh_link);
476 if (std::error_code EC = SymTableOrErr.getError())
478 const Elf_Shdr &SymTable = **SymTableOrErr;
479 if (SymTable.sh_type != ELF::SHT_SYMTAB &&
480 SymTable.sh_type != ELF::SHT_DYNSYM)
481 return object_error::parse_failed;
482 if (NumSymbols != (SymTable.sh_size / sizeof(Elf_Sym)))
483 return object_error::parse_failed;
484 return makeArrayRef(ShndxTableBegin, ShndxTableEnd);
487 template <class ELFT>
489 ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec) const {
490 if (Sec.sh_type != ELF::SHT_SYMTAB && Sec.sh_type != ELF::SHT_DYNSYM)
491 return object_error::parse_failed;
492 ErrorOr<const Elf_Shdr *> SectionOrErr = getSection(Sec.sh_link);
493 if (std::error_code EC = SectionOrErr.getError())
495 return getStringTable(*SectionOrErr);
498 template <class ELFT>
500 ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
501 uint32_t Offset = Section->sh_name;
504 if (Offset >= DotShstrtab.size())
505 return object_error::parse_failed;
506 return StringRef(DotShstrtab.data() + Offset);
509 /// This function returns the hash value for a symbol in the .dynsym section
510 /// Name of the API remains consistent as specified in the libelf
511 /// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
512 static inline unsigned elf_hash(StringRef &symbolName) {
514 for (unsigned i = 0, j = symbolName.size(); i < j; i++) {
515 h = (h << 4) + symbolName[i];
523 } // end namespace object
524 } // end namespace llvm