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/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/PointerIntPair.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/ADT/StringSwitch.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/Object/ELFTypes.h"
24 #include "llvm/Object/Error.h"
25 #include "llvm/Support/Casting.h"
26 #include "llvm/Support/ELF.h"
27 #include "llvm/Support/Endian.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/ErrorOr.h"
30 #include "llvm/Support/MemoryBuffer.h"
31 #include "llvm/Support/raw_ostream.h"
39 StringRef getELFRelocationTypeName(uint32_t Machine, uint32_t Type);
41 // Subclasses of ELFFile may need this for template instantiation
42 inline std::pair<unsigned char, unsigned char>
43 getElfArchType(StringRef Object) {
44 if (Object.size() < ELF::EI_NIDENT)
45 return std::make_pair((uint8_t)ELF::ELFCLASSNONE,
46 (uint8_t)ELF::ELFDATANONE);
47 return std::make_pair((uint8_t)Object[ELF::EI_CLASS],
48 (uint8_t)Object[ELF::EI_DATA]);
54 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
55 typedef typename std::conditional<ELFT::Is64Bits,
56 uint64_t, uint32_t>::type uintX_t;
58 /// \brief Iterate over constant sized entities.
60 class ELFEntityIterator {
62 typedef ptrdiff_t difference_type;
63 typedef EntT value_type;
64 typedef std::forward_iterator_tag iterator_category;
65 typedef value_type &reference;
66 typedef value_type *pointer;
68 /// \brief Default construct iterator.
69 ELFEntityIterator() : EntitySize(0), Current(nullptr) {}
70 ELFEntityIterator(uintX_t EntSize, const char *Start)
71 : EntitySize(EntSize), Current(Start) {}
73 reference operator *() {
74 assert(Current && "Attempted to dereference an invalid iterator!");
75 return *reinterpret_cast<pointer>(Current);
78 pointer operator ->() {
79 assert(Current && "Attempted to dereference an invalid iterator!");
80 return reinterpret_cast<pointer>(Current);
83 bool operator ==(const ELFEntityIterator &Other) {
84 return Current == Other.Current;
87 bool operator !=(const ELFEntityIterator &Other) {
88 return !(*this == Other);
91 ELFEntityIterator &operator ++() {
92 assert(Current && "Attempted to increment an invalid iterator!");
93 Current += EntitySize;
97 ELFEntityIterator &operator+(difference_type n) {
98 assert(Current && "Attempted to increment an invalid iterator!");
99 Current += (n * EntitySize);
103 ELFEntityIterator &operator-(difference_type n) {
104 assert(Current && "Attempted to subtract an invalid iterator!");
105 Current -= (n * EntitySize);
109 ELFEntityIterator operator ++(int) {
110 ELFEntityIterator Tmp = *this;
115 difference_type operator -(const ELFEntityIterator &Other) const {
116 assert(EntitySize == Other.EntitySize &&
117 "Subtracting iterators of different EntitySize!");
118 return (Current - Other.Current) / EntitySize;
121 const char *get() const { return Current; }
123 uintX_t getEntSize() const { return EntitySize; }
130 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
131 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
132 typedef Elf_Sym_Impl<ELFT> Elf_Sym;
133 typedef Elf_Dyn_Impl<ELFT> Elf_Dyn;
134 typedef Elf_Phdr_Impl<ELFT> Elf_Phdr;
135 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
136 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
137 typedef Elf_Verdef_Impl<ELFT> Elf_Verdef;
138 typedef Elf_Verdaux_Impl<ELFT> Elf_Verdaux;
139 typedef Elf_Verneed_Impl<ELFT> Elf_Verneed;
140 typedef Elf_Vernaux_Impl<ELFT> Elf_Vernaux;
141 typedef Elf_Versym_Impl<ELFT> Elf_Versym;
142 typedef Elf_Hash_Impl<ELFT> Elf_Hash;
143 typedef ELFEntityIterator<const Elf_Dyn> Elf_Dyn_Iter;
144 typedef iterator_range<Elf_Dyn_Iter> Elf_Dyn_Range;
145 typedef iterator_range<const Elf_Shdr *> Elf_Shdr_Range;
147 /// \brief Archive files are 2 byte aligned, so we need this for
148 /// PointerIntPair to work.
149 template <typename T>
150 class ArchivePointerTypeTraits {
152 static inline const void *getAsVoidPointer(T *P) { return P; }
153 static inline T *getFromVoidPointer(const void *P) {
154 return static_cast<T *>(P);
156 enum { NumLowBitsAvailable = 1 };
159 typedef iterator_range<const Elf_Sym *> Elf_Sym_Range;
162 typedef SmallVector<const Elf_Shdr *, 2> Sections_t;
163 typedef DenseMap<unsigned, unsigned> IndexMap_t;
167 const uint8_t *base() const {
168 return reinterpret_cast<const uint8_t *>(Buf.data());
171 const Elf_Ehdr *Header;
172 const Elf_Shdr *SectionHeaderTable = nullptr;
173 StringRef DotShstrtab; // Section header string table.
174 StringRef DotStrtab; // Symbol header string table.
175 const Elf_Shdr *dot_symtab_sec = nullptr; // Symbol table section.
176 const Elf_Shdr *DotDynSymSec = nullptr; // Dynamic symbol table section.
177 const Elf_Hash *HashTable = nullptr;
179 const Elf_Shdr *SymbolTableSectionHeaderIndex = nullptr;
180 DenseMap<const Elf_Sym *, ELF::Elf64_Word> ExtendedSymbolTable;
182 const Elf_Shdr *dot_gnu_version_sec = nullptr; // .gnu.version
183 const Elf_Shdr *dot_gnu_version_r_sec = nullptr; // .gnu.version_r
184 const Elf_Shdr *dot_gnu_version_d_sec = nullptr; // .gnu.version_d
186 /// \brief Represents a region described by entries in the .dynamic table.
187 struct DynRegionInfo {
188 DynRegionInfo() : Addr(nullptr), Size(0), EntSize(0) {}
189 /// \brief Address in current address space.
191 /// \brief Size in bytes of the region.
193 /// \brief Size of each entity in the region.
197 DynRegionInfo DynamicRegion;
198 DynRegionInfo DynHashRegion;
199 DynRegionInfo DynStrRegion;
200 DynRegionInfo DynRelaRegion;
202 // Pointer to SONAME entry in dynamic string table
203 // This is set the first time getLoadName is called.
204 mutable const char *dt_soname = nullptr;
206 // Records for each version index the corresponding Verdef or Vernaux entry.
207 // This is filled the first time LoadVersionMap() is called.
208 class VersionMapEntry : public PointerIntPair<const void*, 1> {
210 // If the integer is 0, this is an Elf_Verdef*.
211 // If the integer is 1, this is an Elf_Vernaux*.
212 VersionMapEntry() : PointerIntPair<const void*, 1>(nullptr, 0) { }
213 VersionMapEntry(const Elf_Verdef *verdef)
214 : PointerIntPair<const void*, 1>(verdef, 0) { }
215 VersionMapEntry(const Elf_Vernaux *vernaux)
216 : PointerIntPair<const void*, 1>(vernaux, 1) { }
217 bool isNull() const { return getPointer() == nullptr; }
218 bool isVerdef() const { return !isNull() && getInt() == 0; }
219 bool isVernaux() const { return !isNull() && getInt() == 1; }
220 const Elf_Verdef *getVerdef() const {
221 return isVerdef() ? (const Elf_Verdef*)getPointer() : nullptr;
223 const Elf_Vernaux *getVernaux() const {
224 return isVernaux() ? (const Elf_Vernaux*)getPointer() : nullptr;
227 mutable SmallVector<VersionMapEntry, 16> VersionMap;
228 void LoadVersionDefs(const Elf_Shdr *sec) const;
229 void LoadVersionNeeds(const Elf_Shdr *ec) const;
230 void LoadVersionMap() const;
232 void scanDynamicTable();
236 const T *getEntry(uint32_t Section, uint32_t Entry) const;
237 template <typename T>
238 const T *getEntry(const Elf_Shdr *Section, uint32_t Entry) const;
240 const Elf_Shdr *getDotSymtabSec() const { return dot_symtab_sec; }
241 const Elf_Shdr *getDotDynSymSec() const { return DotDynSymSec; }
242 const Elf_Hash *getHashTable() const { return HashTable; }
244 ErrorOr<StringRef> getStringTable(const Elf_Shdr *Section) const;
245 const char *getDynamicString(uintX_t Offset) const;
246 ErrorOr<StringRef> getSymbolVersion(const Elf_Shdr *section,
248 bool &IsDefault) const;
249 void VerifyStrTab(const Elf_Shdr *sh) const;
251 StringRef getRelocationTypeName(uint32_t Type) const;
252 void getRelocationTypeName(uint32_t Type,
253 SmallVectorImpl<char> &Result) const;
255 /// \brief Get the symbol table section and symbol for a given relocation.
256 template <class RelT>
257 std::pair<const Elf_Shdr *, const Elf_Sym *>
258 getRelocationSymbol(const Elf_Shdr *RelSec, const RelT *Rel) const;
260 ELFFile(StringRef Object, std::error_code &EC);
262 bool isMipsELF64() const {
263 return Header->e_machine == ELF::EM_MIPS &&
264 Header->getFileClass() == ELF::ELFCLASS64;
267 bool isMips64EL() const {
268 return Header->e_machine == ELF::EM_MIPS &&
269 Header->getFileClass() == ELF::ELFCLASS64 &&
270 Header->getDataEncoding() == ELF::ELFDATA2LSB;
273 const Elf_Shdr *section_begin() const;
274 const Elf_Shdr *section_end() const;
275 Elf_Shdr_Range sections() const {
276 return make_range(section_begin(), section_end());
279 const Elf_Sym *symbol_begin() const;
280 const Elf_Sym *symbol_end() const;
281 Elf_Sym_Range symbols() const {
282 return make_range(symbol_begin(), symbol_end());
285 Elf_Dyn_Iter dynamic_table_begin() const;
286 /// \param NULLEnd use one past the first DT_NULL entry as the end instead of
287 /// the section size.
288 Elf_Dyn_Iter dynamic_table_end(bool NULLEnd = false) const;
289 Elf_Dyn_Range dynamic_table(bool NULLEnd = false) const {
290 return make_range(dynamic_table_begin(), dynamic_table_end(NULLEnd));
293 const Elf_Sym *dynamic_symbol_begin() const {
296 if (DotDynSymSec->sh_entsize != sizeof(Elf_Sym))
297 report_fatal_error("Invalid symbol size");
298 return reinterpret_cast<const Elf_Sym *>(base() + DotDynSymSec->sh_offset);
301 const Elf_Sym *dynamic_symbol_end() const {
304 return reinterpret_cast<const Elf_Sym *>(base() + DotDynSymSec->sh_offset +
305 DotDynSymSec->sh_size);
308 Elf_Sym_Range dynamic_symbols() const {
309 return make_range(dynamic_symbol_begin(), dynamic_symbol_end());
312 const Elf_Rela *dyn_rela_begin() const {
313 if (DynRelaRegion.Size && DynRelaRegion.EntSize != sizeof(Elf_Rela))
314 report_fatal_error("Invalid relocation entry size");
315 return reinterpret_cast<const Elf_Rela *>(DynRelaRegion.Addr);
318 const Elf_Rela *dyn_rela_end() const {
319 uint64_t Size = DynRelaRegion.Size;
320 if (Size % sizeof(Elf_Rela))
321 report_fatal_error("Invalid relocation table size");
322 return dyn_rela_begin() + Size / sizeof(Elf_Rela);
325 typedef iterator_range<const Elf_Rela *> Elf_Rela_Range;
327 Elf_Rela_Range dyn_relas() const {
328 return make_range(dyn_rela_begin(), dyn_rela_end());
331 const Elf_Rela *rela_begin(const Elf_Shdr *sec) const {
332 if (sec->sh_entsize != sizeof(Elf_Rela))
333 report_fatal_error("Invalid relocation entry size");
334 return reinterpret_cast<const Elf_Rela *>(base() + sec->sh_offset);
337 const Elf_Rela *rela_end(const Elf_Shdr *sec) const {
338 uint64_t Size = sec->sh_size;
339 if (Size % sizeof(Elf_Rela))
340 report_fatal_error("Invalid relocation table size");
341 return rela_begin(sec) + Size / sizeof(Elf_Rela);
344 Elf_Rela_Range relas(const Elf_Shdr *Sec) const {
345 return make_range(rela_begin(Sec), rela_end(Sec));
348 const Elf_Rel *rel_begin(const Elf_Shdr *sec) const {
349 if (sec->sh_entsize != sizeof(Elf_Rel))
350 report_fatal_error("Invalid relocation entry size");
351 return reinterpret_cast<const Elf_Rel *>(base() + sec->sh_offset);
354 const Elf_Rel *rel_end(const Elf_Shdr *sec) const {
355 uint64_t Size = sec->sh_size;
356 if (Size % sizeof(Elf_Rel))
357 report_fatal_error("Invalid relocation table size");
358 return rel_begin(sec) + Size / sizeof(Elf_Rel);
361 typedef iterator_range<const Elf_Rel *> Elf_Rel_Range;
362 Elf_Rel_Range rels(const Elf_Shdr *Sec) const {
363 return make_range(rel_begin(Sec), rel_end(Sec));
366 /// \brief Iterate over program header table.
367 const Elf_Phdr *program_header_begin() const {
368 if (Header->e_phnum && Header->e_phentsize != sizeof(Elf_Phdr))
369 report_fatal_error("Invalid program header size");
370 return reinterpret_cast<const Elf_Phdr *>(base() + Header->e_phoff);
373 const Elf_Phdr *program_header_end() const {
374 return program_header_begin() + Header->e_phnum;
377 typedef iterator_range<const Elf_Phdr *> Elf_Phdr_Range;
379 const Elf_Phdr_Range program_headers() const {
380 return make_range(program_header_begin(), program_header_end());
383 uint64_t getNumSections() const;
384 uintX_t getStringTableIndex() const;
385 ELF::Elf64_Word getExtendedSymbolTableIndex(const Elf_Sym *symb) const;
386 const Elf_Ehdr *getHeader() const { return Header; }
387 ErrorOr<const Elf_Shdr *> getSection(const Elf_Sym *symb) const;
388 ErrorOr<const Elf_Shdr *> getSection(uint32_t Index) const;
389 const Elf_Sym *getSymbol(uint32_t index) const;
391 ErrorOr<StringRef> getStaticSymbolName(const Elf_Sym *Symb) const;
392 ErrorOr<StringRef> getDynamicSymbolName(const Elf_Sym *Symb) const;
393 ErrorOr<StringRef> getSymbolName(const Elf_Sym *Symb, bool IsDynamic) const;
395 ErrorOr<StringRef> getSectionName(const Elf_Shdr *Section) const;
396 ErrorOr<ArrayRef<uint8_t> > getSectionContents(const Elf_Shdr *Sec) const;
397 StringRef getLoadName() const;
400 typedef ELFFile<ELFType<support::little, false>> ELF32LEFile;
401 typedef ELFFile<ELFType<support::little, true>> ELF64LEFile;
402 typedef ELFFile<ELFType<support::big, false>> ELF32BEFile;
403 typedef ELFFile<ELFType<support::big, true>> ELF64BEFile;
405 // Iterate through the version definitions, and place each Elf_Verdef
406 // in the VersionMap according to its index.
407 template <class ELFT>
408 void ELFFile<ELFT>::LoadVersionDefs(const Elf_Shdr *sec) const {
409 unsigned vd_size = sec->sh_size; // Size of section in bytes
410 unsigned vd_count = sec->sh_info; // Number of Verdef entries
411 const char *sec_start = (const char*)base() + sec->sh_offset;
412 const char *sec_end = sec_start + vd_size;
413 // The first Verdef entry is at the start of the section.
414 const char *p = sec_start;
415 for (unsigned i = 0; i < vd_count; i++) {
416 if (p + sizeof(Elf_Verdef) > sec_end)
417 report_fatal_error("Section ended unexpectedly while scanning "
418 "version definitions.");
419 const Elf_Verdef *vd = reinterpret_cast<const Elf_Verdef *>(p);
420 if (vd->vd_version != ELF::VER_DEF_CURRENT)
421 report_fatal_error("Unexpected verdef version");
422 size_t index = vd->vd_ndx & ELF::VERSYM_VERSION;
423 if (index >= VersionMap.size())
424 VersionMap.resize(index + 1);
425 VersionMap[index] = VersionMapEntry(vd);
430 // Iterate through the versions needed section, and place each Elf_Vernaux
431 // in the VersionMap according to its index.
432 template <class ELFT>
433 void ELFFile<ELFT>::LoadVersionNeeds(const Elf_Shdr *sec) const {
434 unsigned vn_size = sec->sh_size; // Size of section in bytes
435 unsigned vn_count = sec->sh_info; // Number of Verneed entries
436 const char *sec_start = (const char *)base() + sec->sh_offset;
437 const char *sec_end = sec_start + vn_size;
438 // The first Verneed entry is at the start of the section.
439 const char *p = sec_start;
440 for (unsigned i = 0; i < vn_count; i++) {
441 if (p + sizeof(Elf_Verneed) > sec_end)
442 report_fatal_error("Section ended unexpectedly while scanning "
443 "version needed records.");
444 const Elf_Verneed *vn = reinterpret_cast<const Elf_Verneed *>(p);
445 if (vn->vn_version != ELF::VER_NEED_CURRENT)
446 report_fatal_error("Unexpected verneed version");
447 // Iterate through the Vernaux entries
448 const char *paux = p + vn->vn_aux;
449 for (unsigned j = 0; j < vn->vn_cnt; j++) {
450 if (paux + sizeof(Elf_Vernaux) > sec_end)
451 report_fatal_error("Section ended unexpected while scanning auxiliary "
452 "version needed records.");
453 const Elf_Vernaux *vna = reinterpret_cast<const Elf_Vernaux *>(paux);
454 size_t index = vna->vna_other & ELF::VERSYM_VERSION;
455 if (index >= VersionMap.size())
456 VersionMap.resize(index + 1);
457 VersionMap[index] = VersionMapEntry(vna);
458 paux += vna->vna_next;
464 template <class ELFT>
465 void ELFFile<ELFT>::LoadVersionMap() const {
466 // If there is no dynamic symtab or version table, there is nothing to do.
467 if (!DotDynSymSec || !dot_gnu_version_sec)
470 // Has the VersionMap already been loaded?
471 if (VersionMap.size() > 0)
474 // The first two version indexes are reserved.
475 // Index 0 is LOCAL, index 1 is GLOBAL.
476 VersionMap.push_back(VersionMapEntry());
477 VersionMap.push_back(VersionMapEntry());
479 if (dot_gnu_version_d_sec)
480 LoadVersionDefs(dot_gnu_version_d_sec);
482 if (dot_gnu_version_r_sec)
483 LoadVersionNeeds(dot_gnu_version_r_sec);
486 template <class ELFT>
488 ELFFile<ELFT>::getExtendedSymbolTableIndex(const Elf_Sym *symb) const {
489 assert(symb->st_shndx == ELF::SHN_XINDEX);
490 return ExtendedSymbolTable.lookup(symb);
493 template <class ELFT>
494 ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
495 ELFFile<ELFT>::getSection(const Elf_Sym *symb) const {
496 uint32_t Index = symb->st_shndx;
497 if (Index == ELF::SHN_XINDEX)
498 return getSection(ExtendedSymbolTable.lookup(symb));
499 if (Index == ELF::SHN_UNDEF || Index >= ELF::SHN_LORESERVE)
501 return getSection(symb->st_shndx);
504 template <class ELFT>
505 const typename ELFFile<ELFT>::Elf_Sym *
506 ELFFile<ELFT>::getSymbol(uint32_t Index) const {
507 return &*(symbol_begin() + Index);
510 template <class ELFT>
511 ErrorOr<ArrayRef<uint8_t> >
512 ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const {
513 if (Sec->sh_offset + Sec->sh_size > Buf.size())
514 return object_error::parse_failed;
515 const uint8_t *Start = base() + Sec->sh_offset;
516 return makeArrayRef(Start, Sec->sh_size);
519 template <class ELFT>
520 StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const {
521 return getELFRelocationTypeName(Header->e_machine, Type);
524 template <class ELFT>
525 void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
526 SmallVectorImpl<char> &Result) const {
527 if (!isMipsELF64()) {
528 StringRef Name = getRelocationTypeName(Type);
529 Result.append(Name.begin(), Name.end());
531 // The Mips N64 ABI allows up to three operations to be specified per
532 // relocation record. Unfortunately there's no easy way to test for the
533 // presence of N64 ELFs as they have no special flag that identifies them
534 // as being N64. We can safely assume at the moment that all Mips
535 // ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough
536 // information to disambiguate between old vs new ABIs.
537 uint8_t Type1 = (Type >> 0) & 0xFF;
538 uint8_t Type2 = (Type >> 8) & 0xFF;
539 uint8_t Type3 = (Type >> 16) & 0xFF;
541 // Concat all three relocation type names.
542 StringRef Name = getRelocationTypeName(Type1);
543 Result.append(Name.begin(), Name.end());
545 Name = getRelocationTypeName(Type2);
546 Result.append(1, '/');
547 Result.append(Name.begin(), Name.end());
549 Name = getRelocationTypeName(Type3);
550 Result.append(1, '/');
551 Result.append(Name.begin(), Name.end());
555 template <class ELFT>
556 template <class RelT>
557 std::pair<const typename ELFFile<ELFT>::Elf_Shdr *,
558 const typename ELFFile<ELFT>::Elf_Sym *>
559 ELFFile<ELFT>::getRelocationSymbol(const Elf_Shdr *Sec, const RelT *Rel) const {
561 return std::make_pair(nullptr, nullptr);
562 ErrorOr<const Elf_Shdr *> SymTableOrErr = getSection(Sec->sh_link);
563 if (std::error_code EC = SymTableOrErr.getError())
564 report_fatal_error(EC.message());
565 const Elf_Shdr *SymTable = *SymTableOrErr;
566 return std::make_pair(
567 SymTable, getEntry<Elf_Sym>(SymTable, Rel->getSymbol(isMips64EL())));
570 template <class ELFT>
571 uint64_t ELFFile<ELFT>::getNumSections() const {
572 assert(Header && "Header not initialized!");
573 if (Header->e_shnum == ELF::SHN_UNDEF && Header->e_shoff > 0) {
574 assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
575 return SectionHeaderTable->sh_size;
577 return Header->e_shnum;
580 template <class ELFT>
581 typename ELFFile<ELFT>::uintX_t ELFFile<ELFT>::getStringTableIndex() const {
582 if (Header->e_shnum == ELF::SHN_UNDEF) {
583 if (Header->e_shstrndx == ELF::SHN_HIRESERVE)
584 return SectionHeaderTable->sh_link;
585 if (Header->e_shstrndx >= getNumSections())
588 return Header->e_shstrndx;
591 template <class ELFT>
592 ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
594 const uint64_t FileSize = Buf.size();
596 if (sizeof(Elf_Ehdr) > FileSize) {
598 EC = object_error::parse_failed;
602 Header = reinterpret_cast<const Elf_Ehdr *>(base());
604 if (Header->e_shoff == 0) {
609 const uint64_t SectionTableOffset = Header->e_shoff;
611 if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize) {
612 // Section header table goes past end of file!
613 EC = object_error::parse_failed;
617 // The getNumSections() call below depends on SectionHeaderTable being set.
619 reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);
620 const uint64_t SectionTableSize = getNumSections() * Header->e_shentsize;
622 if (SectionTableOffset + SectionTableSize > FileSize) {
623 // Section table goes past end of file!
624 EC = object_error::parse_failed;
628 // Scan sections for special sections.
630 for (const Elf_Shdr &Sec : sections()) {
631 switch (Sec.sh_type) {
634 EC = object_error::parse_failed;
637 HashTable = reinterpret_cast<const Elf_Hash *>(base() + Sec.sh_offset);
639 case ELF::SHT_SYMTAB_SHNDX:
640 if (SymbolTableSectionHeaderIndex) {
641 // More than one .symtab_shndx!
642 EC = object_error::parse_failed;
645 SymbolTableSectionHeaderIndex = &Sec;
647 case ELF::SHT_SYMTAB: {
648 if (dot_symtab_sec) {
649 // More than one .symtab!
650 EC = object_error::parse_failed;
653 dot_symtab_sec = &Sec;
654 ErrorOr<const Elf_Shdr *> SectionOrErr = getSection(Sec.sh_link);
655 if ((EC = SectionOrErr.getError()))
657 ErrorOr<StringRef> SymtabOrErr = getStringTable(*SectionOrErr);
658 if ((EC = SymtabOrErr.getError()))
660 DotStrtab = *SymtabOrErr;
662 case ELF::SHT_DYNSYM: {
664 // More than one .dynsym!
665 EC = object_error::parse_failed;
671 case ELF::SHT_DYNAMIC:
672 if (DynamicRegion.Addr) {
673 // More than one .dynamic!
674 EC = object_error::parse_failed;
677 DynamicRegion.Addr = base() + Sec.sh_offset;
678 DynamicRegion.Size = Sec.sh_size;
679 DynamicRegion.EntSize = Sec.sh_entsize;
681 case ELF::SHT_GNU_versym:
682 if (dot_gnu_version_sec != nullptr) {
683 // More than one .gnu.version section!
684 EC = object_error::parse_failed;
687 dot_gnu_version_sec = &Sec;
689 case ELF::SHT_GNU_verdef:
690 if (dot_gnu_version_d_sec != nullptr) {
691 // More than one .gnu.version_d section!
692 EC = object_error::parse_failed;
695 dot_gnu_version_d_sec = &Sec;
697 case ELF::SHT_GNU_verneed:
698 if (dot_gnu_version_r_sec != nullptr) {
699 // More than one .gnu.version_r section!
700 EC = object_error::parse_failed;
703 dot_gnu_version_r_sec = &Sec;
708 // Get string table sections.
709 ErrorOr<const Elf_Shdr *> StrTabSecOrErr = getSection(getStringTableIndex());
710 if ((EC = StrTabSecOrErr.getError()))
713 ErrorOr<StringRef> SymtabOrErr = getStringTable(*StrTabSecOrErr);
714 if ((EC = SymtabOrErr.getError()))
716 DotShstrtab = *SymtabOrErr;
718 // Build symbol name side-mapping if there is one.
719 if (SymbolTableSectionHeaderIndex) {
720 const Elf_Word *ShndxTable = reinterpret_cast<const Elf_Word*>(base() +
721 SymbolTableSectionHeaderIndex->sh_offset);
722 for (const Elf_Sym &S : symbols()) {
723 if (*ShndxTable != ELF::SHN_UNDEF)
724 ExtendedSymbolTable[&S] = *ShndxTable;
731 EC = std::error_code();
734 template <class ELFT>
735 static bool compareAddr(uint64_t VAddr, const Elf_Phdr_Impl<ELFT> *Phdr) {
736 return VAddr < Phdr->p_vaddr;
739 template <class ELFT> void ELFFile<ELFT>::scanDynamicTable() {
740 SmallVector<const Elf_Phdr *, 4> LoadSegments;
741 for (const Elf_Phdr &Phdr : program_headers()) {
742 if (Phdr.p_type == ELF::PT_DYNAMIC) {
743 DynamicRegion.Addr = base() + Phdr.p_offset;
744 DynamicRegion.Size = Phdr.p_filesz;
745 DynamicRegion.EntSize = sizeof(Elf_Dyn);
748 if (Phdr.p_type != ELF::PT_LOAD || Phdr.p_filesz == 0)
750 LoadSegments.push_back(&Phdr);
753 auto toMappedAddr = [&](uint64_t VAddr) -> const uint8_t * {
754 const Elf_Phdr **I = std::upper_bound(
755 LoadSegments.begin(), LoadSegments.end(), VAddr, compareAddr<ELFT>);
756 if (I == LoadSegments.begin())
757 report_fatal_error("Virtual address is not in any segment");
759 const Elf_Phdr &Phdr = **I;
760 uint64_t Delta = VAddr - Phdr.p_vaddr;
761 if (Delta >= Phdr.p_filesz)
762 report_fatal_error("Virtual address is not in any segment");
763 return this->base() + Phdr.p_offset + Delta;
766 for (Elf_Dyn_Iter DynI = dynamic_table_begin(), DynE = dynamic_table_end();
767 DynI != DynE; ++DynI) {
768 switch (DynI->d_tag) {
773 reinterpret_cast<const Elf_Hash *>(toMappedAddr(DynI->getPtr()));
776 if (!DynStrRegion.Addr)
777 DynStrRegion.Addr = toMappedAddr(DynI->getPtr());
780 if (!DynStrRegion.Size)
781 DynStrRegion.Size = DynI->getVal();
784 if (!DynRelaRegion.Addr)
785 DynRelaRegion.Addr = toMappedAddr(DynI->getPtr());
788 DynRelaRegion.Size = DynI->getVal();
790 case ELF::DT_RELAENT:
791 DynRelaRegion.EntSize = DynI->getVal();
796 template <class ELFT>
797 const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_begin() const {
798 if (Header->e_shentsize != sizeof(Elf_Shdr))
800 "Invalid section header entry size (e_shentsize) in ELF header");
801 return reinterpret_cast<const Elf_Shdr *>(base() + Header->e_shoff);
804 template <class ELFT>
805 const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_end() const {
806 return section_begin() + getNumSections();
809 template <class ELFT>
810 const typename ELFFile<ELFT>::Elf_Sym *ELFFile<ELFT>::symbol_begin() const {
813 if (dot_symtab_sec->sh_entsize != sizeof(Elf_Sym))
814 report_fatal_error("Invalid symbol size");
815 return reinterpret_cast<const Elf_Sym *>(base() + dot_symtab_sec->sh_offset);
818 template <class ELFT>
819 const typename ELFFile<ELFT>::Elf_Sym *ELFFile<ELFT>::symbol_end() const {
822 return reinterpret_cast<const Elf_Sym *>(base() + dot_symtab_sec->sh_offset +
823 dot_symtab_sec->sh_size);
826 template <class ELFT>
827 typename ELFFile<ELFT>::Elf_Dyn_Iter
828 ELFFile<ELFT>::dynamic_table_begin() const {
829 if (DynamicRegion.Addr)
830 return Elf_Dyn_Iter(DynamicRegion.EntSize,
831 (const char *)DynamicRegion.Addr);
832 return Elf_Dyn_Iter(0, nullptr);
835 template <class ELFT>
836 typename ELFFile<ELFT>::Elf_Dyn_Iter
837 ELFFile<ELFT>::dynamic_table_end(bool NULLEnd) const {
838 if (!DynamicRegion.Addr)
839 return Elf_Dyn_Iter(0, nullptr);
840 Elf_Dyn_Iter Ret(DynamicRegion.EntSize,
841 (const char *)DynamicRegion.Addr + DynamicRegion.Size);
844 Elf_Dyn_Iter Start = dynamic_table_begin();
845 while (Start != Ret && Start->getTag() != ELF::DT_NULL)
848 // Include the DT_NULL.
856 template <class ELFT>
857 StringRef ELFFile<ELFT>::getLoadName() const {
860 // Find the DT_SONAME entry
861 for (const auto &Entry : dynamic_table())
862 if (Entry.getTag() == ELF::DT_SONAME) {
863 dt_soname = getDynamicString(Entry.getVal());
870 template <class ELFT>
871 template <typename T>
872 const T *ELFFile<ELFT>::getEntry(uint32_t Section, uint32_t Entry) const {
873 ErrorOr<const Elf_Shdr *> Sec = getSection(Section);
874 if (std::error_code EC = Sec.getError())
875 report_fatal_error(EC.message());
876 return getEntry<T>(*Sec, Entry);
879 template <class ELFT>
880 template <typename T>
881 const T *ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
882 uint32_t Entry) const {
883 return reinterpret_cast<const T *>(base() + Section->sh_offset +
884 (Entry * Section->sh_entsize));
887 template <class ELFT>
888 ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
889 ELFFile<ELFT>::getSection(uint32_t Index) const {
890 assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
891 if (Index >= getNumSections())
892 return object_error::invalid_section_index;
894 return reinterpret_cast<const Elf_Shdr *>(
895 reinterpret_cast<const char *>(SectionHeaderTable) +
896 (Index * Header->e_shentsize));
899 template <class ELFT>
901 ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
902 if (Section->sh_type != ELF::SHT_STRTAB)
903 return object_error::parse_failed;
904 uint64_t Offset = Section->sh_offset;
905 uint64_t Size = Section->sh_size;
906 if (Offset + Size > Buf.size())
907 return object_error::parse_failed;
908 StringRef Data((const char *)base() + Section->sh_offset, Size);
909 if (Data[Size - 1] != '\0')
910 return object_error::string_table_non_null_end;
914 template <class ELFT>
915 const char *ELFFile<ELFT>::getDynamicString(uintX_t Offset) const {
916 if (Offset >= DynStrRegion.Size)
918 return (const char *)DynStrRegion.Addr + Offset;
921 template <class ELFT>
923 ELFFile<ELFT>::getStaticSymbolName(const Elf_Sym *Symb) const {
924 return Symb->getName(DotStrtab);
927 template <class ELFT>
929 ELFFile<ELFT>::getDynamicSymbolName(const Elf_Sym *Symb) const {
930 return StringRef(getDynamicString(Symb->st_name));
933 template <class ELFT>
934 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolName(const Elf_Sym *Symb,
935 bool IsDynamic) const {
937 return getDynamicSymbolName(Symb);
938 return getStaticSymbolName(Symb);
941 template <class ELFT>
943 ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
944 uint32_t Offset = Section->sh_name;
945 if (Offset >= DotShstrtab.size())
946 return object_error::parse_failed;
947 return StringRef(DotShstrtab.data() + Offset);
950 template <class ELFT>
951 ErrorOr<StringRef> ELFFile<ELFT>::getSymbolVersion(const Elf_Shdr *section,
953 bool &IsDefault) const {
956 ErrorOr<StringRef> StrTabOrErr = getStringTable(section);
957 if (std::error_code EC = StrTabOrErr.getError())
959 StrTab = *StrTabOrErr;
961 // Handle non-dynamic symbols.
962 if (section != DotDynSymSec && section != nullptr) {
963 // Non-dynamic symbols can have versions in their names
964 // A name of the form 'foo@V1' indicates version 'V1', non-default.
965 // A name of the form 'foo@@V2' indicates version 'V2', default version.
966 ErrorOr<StringRef> SymName = symb->getName(StrTab);
969 StringRef Name = *SymName;
970 size_t atpos = Name.find('@');
971 if (atpos == StringRef::npos) {
973 return StringRef("");
976 if (atpos < Name.size() && Name[atpos] == '@') {
982 return Name.substr(atpos);
985 // This is a dynamic symbol. Look in the GNU symbol version table.
986 if (!dot_gnu_version_sec) {
989 return StringRef("");
992 // Determine the position in the symbol table of this entry.
994 (reinterpret_cast<uintptr_t>(symb) - DotDynSymSec->sh_offset -
995 reinterpret_cast<uintptr_t>(base())) /
998 // Get the corresponding version index entry
999 const Elf_Versym *vs = getEntry<Elf_Versym>(dot_gnu_version_sec, entry_index);
1000 size_t version_index = vs->vs_index & ELF::VERSYM_VERSION;
1002 // Special markers for unversioned symbols.
1003 if (version_index == ELF::VER_NDX_LOCAL ||
1004 version_index == ELF::VER_NDX_GLOBAL) {
1006 return StringRef("");
1009 // Lookup this symbol in the version table
1011 if (version_index >= VersionMap.size() || VersionMap[version_index].isNull())
1012 return object_error::parse_failed;
1013 const VersionMapEntry &entry = VersionMap[version_index];
1015 // Get the version name string
1017 if (entry.isVerdef()) {
1018 // The first Verdaux entry holds the name.
1019 name_offset = entry.getVerdef()->getAux()->vda_name;
1021 name_offset = entry.getVernaux()->vna_name;
1025 if (entry.isVerdef()) {
1026 IsDefault = !(vs->vs_index & ELF::VERSYM_HIDDEN);
1031 if (name_offset >= DynStrRegion.Size)
1032 return object_error::parse_failed;
1033 return StringRef(getDynamicString(name_offset));
1036 /// This function returns the hash value for a symbol in the .dynsym section
1037 /// Name of the API remains consistent as specified in the libelf
1038 /// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
1039 static inline unsigned elf_hash(StringRef &symbolName) {
1041 for (unsigned i = 0, j = symbolName.size(); i < j; i++) {
1042 h = (h << 4) + symbolName[i];
1043 g = h & 0xf0000000L;
1050 } // end namespace object
1051 } // end namespace llvm