| //===- ELF.h - ELF object file implementation -------------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file declares the ELFFile template class. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_OBJECT_ELF_H |
| #define LLVM_OBJECT_ELF_H |
| |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/BinaryFormat/ELF.h" |
| #include "llvm/Object/ELFTypes.h" |
| #include "llvm/Object/Error.h" |
| #include "llvm/Support/Endian.h" |
| #include "llvm/Support/Error.h" |
| #include <cassert> |
| #include <cstddef> |
| #include <cstdint> |
| #include <limits> |
| #include <utility> |
| |
| namespace llvm { |
| namespace object { |
| |
| StringRef getELFRelocationTypeName(uint32_t Machine, uint32_t Type); |
| uint32_t getELFRelativeRelocationType(uint32_t Machine); |
| StringRef getELFSectionTypeName(uint32_t Machine, uint32_t Type); |
| |
| // Subclasses of ELFFile may need this for template instantiation |
| inline std::pair<unsigned char, unsigned char> |
| getElfArchType(StringRef Object) { |
| if (Object.size() < ELF::EI_NIDENT) |
| return std::make_pair((uint8_t)ELF::ELFCLASSNONE, |
| (uint8_t)ELF::ELFDATANONE); |
| return std::make_pair((uint8_t)Object[ELF::EI_CLASS], |
| (uint8_t)Object[ELF::EI_DATA]); |
| } |
| |
| static inline Error createError(const Twine &Err) { |
| return make_error<StringError>(Err, object_error::parse_failed); |
| } |
| |
| template <class ELFT> class ELFFile; |
| |
| template <class ELFT> |
| std::string getSecIndexForError(const ELFFile<ELFT> *Obj, |
| const typename ELFT::Shdr *Sec) { |
| auto TableOrErr = Obj->sections(); |
| if (TableOrErr) |
| return "[index " + std::to_string(Sec - &TableOrErr->front()) + "]"; |
| // To make this helper be more convenient for error reporting purposes we |
| // drop the error. But really it should never be triggered. Before this point, |
| // our code should have called 'sections()' and reported a proper error on |
| // failure. |
| llvm::consumeError(TableOrErr.takeError()); |
| return "[unknown index]"; |
| } |
| |
| static inline Error defaultWarningHandler(const Twine &Msg) { |
| return createError(Msg); |
| } |
| |
| template <class ELFT> |
| class ELFFile { |
| public: |
| LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) |
| using uintX_t = typename ELFT::uint; |
| using Elf_Ehdr = typename ELFT::Ehdr; |
| using Elf_Shdr = typename ELFT::Shdr; |
| using Elf_Sym = typename ELFT::Sym; |
| using Elf_Dyn = typename ELFT::Dyn; |
| using Elf_Phdr = typename ELFT::Phdr; |
| using Elf_Rel = typename ELFT::Rel; |
| using Elf_Rela = typename ELFT::Rela; |
| using Elf_Relr = typename ELFT::Relr; |
| using Elf_Verdef = typename ELFT::Verdef; |
| using Elf_Verdaux = typename ELFT::Verdaux; |
| using Elf_Verneed = typename ELFT::Verneed; |
| using Elf_Vernaux = typename ELFT::Vernaux; |
| using Elf_Versym = typename ELFT::Versym; |
| using Elf_Hash = typename ELFT::Hash; |
| using Elf_GnuHash = typename ELFT::GnuHash; |
| using Elf_Nhdr = typename ELFT::Nhdr; |
| using Elf_Note = typename ELFT::Note; |
| using Elf_Note_Iterator = typename ELFT::NoteIterator; |
| using Elf_Dyn_Range = typename ELFT::DynRange; |
| using Elf_Shdr_Range = typename ELFT::ShdrRange; |
| using Elf_Sym_Range = typename ELFT::SymRange; |
| using Elf_Rel_Range = typename ELFT::RelRange; |
| using Elf_Rela_Range = typename ELFT::RelaRange; |
| using Elf_Relr_Range = typename ELFT::RelrRange; |
| using Elf_Phdr_Range = typename ELFT::PhdrRange; |
| |
| // This is a callback that can be passed to a number of functions. |
| // It can be used to ignore non-critical errors (warnings), which is |
| // useful for dumpers, like llvm-readobj. |
| // It accepts a warning message string and returns a success |
| // when the warning should be ignored or an error otherwise. |
| using WarningHandler = llvm::function_ref<Error(const Twine &Msg)>; |
| |
| const uint8_t *base() const { return Buf.bytes_begin(); } |
| |
| size_t getBufSize() const { return Buf.size(); } |
| |
| private: |
| StringRef Buf; |
| |
| ELFFile(StringRef Object); |
| |
| public: |
| const Elf_Ehdr *getHeader() const { |
| return reinterpret_cast<const Elf_Ehdr *>(base()); |
| } |
| |
| template <typename T> |
| Expected<const T *> getEntry(uint32_t Section, uint32_t Entry) const; |
| template <typename T> |
| Expected<const T *> getEntry(const Elf_Shdr *Section, uint32_t Entry) const; |
| |
| Expected<StringRef> |
| getStringTable(const Elf_Shdr *Section, |
| WarningHandler WarnHandler = &defaultWarningHandler) const; |
| Expected<StringRef> getStringTableForSymtab(const Elf_Shdr &Section) const; |
| Expected<StringRef> getStringTableForSymtab(const Elf_Shdr &Section, |
| Elf_Shdr_Range Sections) const; |
| |
| Expected<ArrayRef<Elf_Word>> getSHNDXTable(const Elf_Shdr &Section) const; |
| Expected<ArrayRef<Elf_Word>> getSHNDXTable(const Elf_Shdr &Section, |
| Elf_Shdr_Range Sections) const; |
| |
| StringRef getRelocationTypeName(uint32_t Type) const; |
| void getRelocationTypeName(uint32_t Type, |
| SmallVectorImpl<char> &Result) const; |
| uint32_t getRelativeRelocationType() const; |
| |
| std::string getDynamicTagAsString(unsigned Arch, uint64_t Type) const; |
| std::string getDynamicTagAsString(uint64_t Type) const; |
| |
| /// Get the symbol for a given relocation. |
| Expected<const Elf_Sym *> getRelocationSymbol(const Elf_Rel *Rel, |
| const Elf_Shdr *SymTab) const; |
| |
| static Expected<ELFFile> create(StringRef Object); |
| |
| bool isLE() const { |
| return getHeader()->getDataEncoding() == ELF::ELFDATA2LSB; |
| } |
| |
| bool isMipsELF64() const { |
| return getHeader()->e_machine == ELF::EM_MIPS && |
| getHeader()->getFileClass() == ELF::ELFCLASS64; |
| } |
| |
| bool isMips64EL() const { return isMipsELF64() && isLE(); } |
| |
| Expected<Elf_Shdr_Range> sections() const; |
| |
| Expected<Elf_Dyn_Range> dynamicEntries() const; |
| |
| Expected<const uint8_t *> toMappedAddr(uint64_t VAddr) const; |
| |
| Expected<Elf_Sym_Range> symbols(const Elf_Shdr *Sec) const { |
| if (!Sec) |
| return makeArrayRef<Elf_Sym>(nullptr, nullptr); |
| return getSectionContentsAsArray<Elf_Sym>(Sec); |
| } |
| |
| Expected<Elf_Rela_Range> relas(const Elf_Shdr *Sec) const { |
| return getSectionContentsAsArray<Elf_Rela>(Sec); |
| } |
| |
| Expected<Elf_Rel_Range> rels(const Elf_Shdr *Sec) const { |
| return getSectionContentsAsArray<Elf_Rel>(Sec); |
| } |
| |
| Expected<Elf_Relr_Range> relrs(const Elf_Shdr *Sec) const { |
| return getSectionContentsAsArray<Elf_Relr>(Sec); |
| } |
| |
| Expected<std::vector<Elf_Rela>> decode_relrs(Elf_Relr_Range relrs) const; |
| |
| Expected<std::vector<Elf_Rela>> android_relas(const Elf_Shdr *Sec) const; |
| |
| /// Iterate over program header table. |
| Expected<Elf_Phdr_Range> program_headers() const { |
| if (getHeader()->e_phnum && getHeader()->e_phentsize != sizeof(Elf_Phdr)) |
| return createError("invalid e_phentsize: " + |
| Twine(getHeader()->e_phentsize)); |
| if (getHeader()->e_phoff + |
| (getHeader()->e_phnum * getHeader()->e_phentsize) > |
| getBufSize()) |
| return createError("program headers are longer than binary of size " + |
| Twine(getBufSize()) + ": e_phoff = 0x" + |
| Twine::utohexstr(getHeader()->e_phoff) + |
| ", e_phnum = " + Twine(getHeader()->e_phnum) + |
| ", e_phentsize = " + Twine(getHeader()->e_phentsize)); |
| auto *Begin = |
| reinterpret_cast<const Elf_Phdr *>(base() + getHeader()->e_phoff); |
| return makeArrayRef(Begin, Begin + getHeader()->e_phnum); |
| } |
| |
| /// Get an iterator over notes in a program header. |
| /// |
| /// The program header must be of type \c PT_NOTE. |
| /// |
| /// \param Phdr the program header to iterate over. |
| /// \param Err [out] an error to support fallible iteration, which should |
| /// be checked after iteration ends. |
| Elf_Note_Iterator notes_begin(const Elf_Phdr &Phdr, Error &Err) const { |
| assert(Phdr.p_type == ELF::PT_NOTE && "Phdr is not of type PT_NOTE"); |
| ErrorAsOutParameter ErrAsOutParam(&Err); |
| if (Phdr.p_offset + Phdr.p_filesz > getBufSize()) { |
| Err = createError("PT_NOTE header has invalid offset (0x" + |
| Twine::utohexstr(Phdr.p_offset) + ") or size (0x" + |
| Twine::utohexstr(Phdr.p_filesz) + ")"); |
| return Elf_Note_Iterator(Err); |
| } |
| return Elf_Note_Iterator(base() + Phdr.p_offset, Phdr.p_filesz, Err); |
| } |
| |
| /// Get an iterator over notes in a section. |
| /// |
| /// The section must be of type \c SHT_NOTE. |
| /// |
| /// \param Shdr the section to iterate over. |
| /// \param Err [out] an error to support fallible iteration, which should |
| /// be checked after iteration ends. |
| Elf_Note_Iterator notes_begin(const Elf_Shdr &Shdr, Error &Err) const { |
| assert(Shdr.sh_type == ELF::SHT_NOTE && "Shdr is not of type SHT_NOTE"); |
| ErrorAsOutParameter ErrAsOutParam(&Err); |
| if (Shdr.sh_offset + Shdr.sh_size > getBufSize()) { |
| Err = createError("SHT_NOTE section " + getSecIndexForError(this, &Shdr) + |
| " has invalid offset (0x" + |
| Twine::utohexstr(Shdr.sh_offset) + ") or size (0x" + |
| Twine::utohexstr(Shdr.sh_size) + ")"); |
| return Elf_Note_Iterator(Err); |
| } |
| return Elf_Note_Iterator(base() + Shdr.sh_offset, Shdr.sh_size, Err); |
| } |
| |
| /// Get the end iterator for notes. |
| Elf_Note_Iterator notes_end() const { |
| return Elf_Note_Iterator(); |
| } |
| |
| /// Get an iterator range over notes of a program header. |
| /// |
| /// The program header must be of type \c PT_NOTE. |
| /// |
| /// \param Phdr the program header to iterate over. |
| /// \param Err [out] an error to support fallible iteration, which should |
| /// be checked after iteration ends. |
| iterator_range<Elf_Note_Iterator> notes(const Elf_Phdr &Phdr, |
| Error &Err) const { |
| return make_range(notes_begin(Phdr, Err), notes_end()); |
| } |
| |
| /// Get an iterator range over notes of a section. |
| /// |
| /// The section must be of type \c SHT_NOTE. |
| /// |
| /// \param Shdr the section to iterate over. |
| /// \param Err [out] an error to support fallible iteration, which should |
| /// be checked after iteration ends. |
| iterator_range<Elf_Note_Iterator> notes(const Elf_Shdr &Shdr, |
| Error &Err) const { |
| return make_range(notes_begin(Shdr, Err), notes_end()); |
| } |
| |
| Expected<StringRef> getSectionStringTable( |
| Elf_Shdr_Range Sections, |
| WarningHandler WarnHandler = &defaultWarningHandler) const; |
| Expected<uint32_t> getSectionIndex(const Elf_Sym *Sym, Elf_Sym_Range Syms, |
| ArrayRef<Elf_Word> ShndxTable) const; |
| Expected<const Elf_Shdr *> getSection(const Elf_Sym *Sym, |
| const Elf_Shdr *SymTab, |
| ArrayRef<Elf_Word> ShndxTable) const; |
| Expected<const Elf_Shdr *> getSection(const Elf_Sym *Sym, |
| Elf_Sym_Range Symtab, |
| ArrayRef<Elf_Word> ShndxTable) const; |
| Expected<const Elf_Shdr *> getSection(uint32_t Index) const; |
| |
| Expected<const Elf_Sym *> getSymbol(const Elf_Shdr *Sec, |
| uint32_t Index) const; |
| |
| Expected<StringRef> |
| getSectionName(const Elf_Shdr *Section, |
| WarningHandler WarnHandler = &defaultWarningHandler) const; |
| Expected<StringRef> getSectionName(const Elf_Shdr *Section, |
| StringRef DotShstrtab) const; |
| template <typename T> |
| Expected<ArrayRef<T>> getSectionContentsAsArray(const Elf_Shdr *Sec) const; |
| Expected<ArrayRef<uint8_t>> getSectionContents(const Elf_Shdr *Sec) const; |
| }; |
| |
| using ELF32LEFile = ELFFile<ELF32LE>; |
| using ELF64LEFile = ELFFile<ELF64LE>; |
| using ELF32BEFile = ELFFile<ELF32BE>; |
| using ELF64BEFile = ELFFile<ELF64BE>; |
| |
| template <class ELFT> |
| inline Expected<const typename ELFT::Shdr *> |
| getSection(typename ELFT::ShdrRange Sections, uint32_t Index) { |
| if (Index >= Sections.size()) |
| return createError("invalid section index: " + Twine(Index)); |
| return &Sections[Index]; |
| } |
| |
| template <class ELFT> |
| inline Expected<uint32_t> |
| getExtendedSymbolTableIndex(const typename ELFT::Sym *Sym, |
| const typename ELFT::Sym *FirstSym, |
| ArrayRef<typename ELFT::Word> ShndxTable) { |
| assert(Sym->st_shndx == ELF::SHN_XINDEX); |
| unsigned Index = Sym - FirstSym; |
| if (Index >= ShndxTable.size()) |
| return createError( |
| "extended symbol index (" + Twine(Index) + |
| ") is past the end of the SHT_SYMTAB_SHNDX section of size " + |
| Twine(ShndxTable.size())); |
| |
| // The size of the table was checked in getSHNDXTable. |
| return ShndxTable[Index]; |
| } |
| |
| template <class ELFT> |
| Expected<uint32_t> |
| ELFFile<ELFT>::getSectionIndex(const Elf_Sym *Sym, Elf_Sym_Range Syms, |
| ArrayRef<Elf_Word> ShndxTable) const { |
| uint32_t Index = Sym->st_shndx; |
| if (Index == ELF::SHN_XINDEX) { |
| auto ErrorOrIndex = getExtendedSymbolTableIndex<ELFT>( |
| Sym, Syms.begin(), ShndxTable); |
| if (!ErrorOrIndex) |
| return ErrorOrIndex.takeError(); |
| return *ErrorOrIndex; |
| } |
| if (Index == ELF::SHN_UNDEF || Index >= ELF::SHN_LORESERVE) |
| return 0; |
| return Index; |
| } |
| |
| template <class ELFT> |
| Expected<const typename ELFT::Shdr *> |
| ELFFile<ELFT>::getSection(const Elf_Sym *Sym, const Elf_Shdr *SymTab, |
| ArrayRef<Elf_Word> ShndxTable) const { |
| auto SymsOrErr = symbols(SymTab); |
| if (!SymsOrErr) |
| return SymsOrErr.takeError(); |
| return getSection(Sym, *SymsOrErr, ShndxTable); |
| } |
| |
| template <class ELFT> |
| Expected<const typename ELFT::Shdr *> |
| ELFFile<ELFT>::getSection(const Elf_Sym *Sym, Elf_Sym_Range Symbols, |
| ArrayRef<Elf_Word> ShndxTable) const { |
| auto IndexOrErr = getSectionIndex(Sym, Symbols, ShndxTable); |
| if (!IndexOrErr) |
| return IndexOrErr.takeError(); |
| uint32_t Index = *IndexOrErr; |
| if (Index == 0) |
| return nullptr; |
| return getSection(Index); |
| } |
| |
| template <class ELFT> |
| Expected<const typename ELFT::Sym *> |
| ELFFile<ELFT>::getSymbol(const Elf_Shdr *Sec, uint32_t Index) const { |
| auto SymsOrErr = symbols(Sec); |
| if (!SymsOrErr) |
| return SymsOrErr.takeError(); |
| |
| Elf_Sym_Range Symbols = *SymsOrErr; |
| if (Index >= Symbols.size()) |
| return createError("unable to get symbol from section " + |
| getSecIndexForError(this, Sec) + |
| ": invalid symbol index (" + Twine(Index) + ")"); |
| return &Symbols[Index]; |
| } |
| |
| template <class ELFT> |
| template <typename T> |
| Expected<ArrayRef<T>> |
| ELFFile<ELFT>::getSectionContentsAsArray(const Elf_Shdr *Sec) const { |
| if (Sec->sh_entsize != sizeof(T) && sizeof(T) != 1) |
| return createError("section " + getSecIndexForError(this, Sec) + |
| " has an invalid sh_entsize: " + Twine(Sec->sh_entsize)); |
| |
| uintX_t Offset = Sec->sh_offset; |
| uintX_t Size = Sec->sh_size; |
| |
| if (Size % sizeof(T)) |
| return createError("section " + getSecIndexForError(this, Sec) + |
| " has an invalid sh_size (" + Twine(Size) + |
| ") which is not a multiple of its sh_entsize (" + |
| Twine(Sec->sh_entsize) + ")"); |
| if (std::numeric_limits<uintX_t>::max() - Offset < Size) |
| return createError("section " + getSecIndexForError(this, Sec) + |
| " has a sh_offset (0x" + Twine::utohexstr(Offset) + |
| ") + sh_size (0x" + Twine::utohexstr(Size) + |
| ") that cannot be represented"); |
| if (Offset + Size > Buf.size()) |
| return createError("section " + getSecIndexForError(this, Sec) + |
| " has a sh_offset (0x" + Twine::utohexstr(Offset) + |
| ") + sh_size (0x" + Twine::utohexstr(Size) + |
| ") that is greater than the file size (0x" + |
| Twine::utohexstr(Buf.size()) + ")"); |
| |
| if (Offset % alignof(T)) |
| // TODO: this error is untested. |
| return createError("unaligned data"); |
| |
| const T *Start = reinterpret_cast<const T *>(base() + Offset); |
| return makeArrayRef(Start, Size / sizeof(T)); |
| } |
| |
| template <class ELFT> |
| Expected<ArrayRef<uint8_t>> |
| ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const { |
| return getSectionContentsAsArray<uint8_t>(Sec); |
| } |
| |
| template <class ELFT> |
| StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const { |
| return getELFRelocationTypeName(getHeader()->e_machine, Type); |
| } |
| |
| template <class ELFT> |
| void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type, |
| SmallVectorImpl<char> &Result) const { |
| if (!isMipsELF64()) { |
| StringRef Name = getRelocationTypeName(Type); |
| Result.append(Name.begin(), Name.end()); |
| } else { |
| // The Mips N64 ABI allows up to three operations to be specified per |
| // relocation record. Unfortunately there's no easy way to test for the |
| // presence of N64 ELFs as they have no special flag that identifies them |
| // as being N64. We can safely assume at the moment that all Mips |
| // ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough |
| // information to disambiguate between old vs new ABIs. |
| uint8_t Type1 = (Type >> 0) & 0xFF; |
| uint8_t Type2 = (Type >> 8) & 0xFF; |
| uint8_t Type3 = (Type >> 16) & 0xFF; |
| |
| // Concat all three relocation type names. |
| StringRef Name = getRelocationTypeName(Type1); |
| Result.append(Name.begin(), Name.end()); |
| |
| Name = getRelocationTypeName(Type2); |
| Result.append(1, '/'); |
| Result.append(Name.begin(), Name.end()); |
| |
| Name = getRelocationTypeName(Type3); |
| Result.append(1, '/'); |
| Result.append(Name.begin(), Name.end()); |
| } |
| } |
| |
| template <class ELFT> |
| uint32_t ELFFile<ELFT>::getRelativeRelocationType() const { |
| return getELFRelativeRelocationType(getHeader()->e_machine); |
| } |
| |
| template <class ELFT> |
| Expected<const typename ELFT::Sym *> |
| ELFFile<ELFT>::getRelocationSymbol(const Elf_Rel *Rel, |
| const Elf_Shdr *SymTab) const { |
| uint32_t Index = Rel->getSymbol(isMips64EL()); |
| if (Index == 0) |
| return nullptr; |
| return getEntry<Elf_Sym>(SymTab, Index); |
| } |
| |
| template <class ELFT> |
| Expected<StringRef> |
| ELFFile<ELFT>::getSectionStringTable(Elf_Shdr_Range Sections, |
| WarningHandler WarnHandler) const { |
| uint32_t Index = getHeader()->e_shstrndx; |
| if (Index == ELF::SHN_XINDEX) |
| Index = Sections[0].sh_link; |
| |
| if (!Index) // no section string table. |
| return ""; |
| if (Index >= Sections.size()) |
| return createError("section header string table index " + Twine(Index) + |
| " does not exist"); |
| return getStringTable(&Sections[Index], WarnHandler); |
| } |
| |
| template <class ELFT> ELFFile<ELFT>::ELFFile(StringRef Object) : Buf(Object) {} |
| |
| template <class ELFT> |
| Expected<ELFFile<ELFT>> ELFFile<ELFT>::create(StringRef Object) { |
| if (sizeof(Elf_Ehdr) > Object.size()) |
| return createError("invalid buffer: the size (" + Twine(Object.size()) + |
| ") is smaller than an ELF header (" + |
| Twine(sizeof(Elf_Ehdr)) + ")"); |
| return ELFFile(Object); |
| } |
| |
| template <class ELFT> |
| Expected<typename ELFT::ShdrRange> ELFFile<ELFT>::sections() const { |
| const uintX_t SectionTableOffset = getHeader()->e_shoff; |
| if (SectionTableOffset == 0) |
| return ArrayRef<Elf_Shdr>(); |
| |
| if (getHeader()->e_shentsize != sizeof(Elf_Shdr)) |
| return createError("invalid e_shentsize in ELF header: " + |
| Twine(getHeader()->e_shentsize)); |
| |
| const uint64_t FileSize = Buf.size(); |
| if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize || |
| SectionTableOffset + (uintX_t)sizeof(Elf_Shdr) < SectionTableOffset) |
| return createError( |
| "section header table goes past the end of the file: e_shoff = 0x" + |
| Twine::utohexstr(SectionTableOffset)); |
| |
| // Invalid address alignment of section headers |
| if (SectionTableOffset & (alignof(Elf_Shdr) - 1)) |
| // TODO: this error is untested. |
| return createError("invalid alignment of section headers"); |
| |
| const Elf_Shdr *First = |
| reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset); |
| |
| uintX_t NumSections = getHeader()->e_shnum; |
| if (NumSections == 0) |
| NumSections = First->sh_size; |
| |
| if (NumSections > UINT64_MAX / sizeof(Elf_Shdr)) |
| return createError("invalid number of sections specified in the NULL " |
| "section's sh_size field (" + |
| Twine(NumSections) + ")"); |
| |
| const uint64_t SectionTableSize = NumSections * sizeof(Elf_Shdr); |
| if (SectionTableOffset + SectionTableSize < SectionTableOffset) |
| return createError( |
| "invalid section header table offset (e_shoff = 0x" + |
| Twine::utohexstr(SectionTableOffset) + |
| ") or invalid number of sections specified in the first section " |
| "header's sh_size field (0x" + |
| Twine::utohexstr(NumSections) + ")"); |
| |
| // Section table goes past end of file! |
| if (SectionTableOffset + SectionTableSize > FileSize) |
| return createError("section table goes past the end of file"); |
| return makeArrayRef(First, NumSections); |
| } |
| |
| template <class ELFT> |
| template <typename T> |
| Expected<const T *> ELFFile<ELFT>::getEntry(uint32_t Section, |
| uint32_t Entry) const { |
| auto SecOrErr = getSection(Section); |
| if (!SecOrErr) |
| return SecOrErr.takeError(); |
| return getEntry<T>(*SecOrErr, Entry); |
| } |
| |
| template <class ELFT> |
| template <typename T> |
| Expected<const T *> ELFFile<ELFT>::getEntry(const Elf_Shdr *Section, |
| uint32_t Entry) const { |
| if (sizeof(T) != Section->sh_entsize) |
| return createError("section " + getSecIndexForError(this, Section) + |
| " has invalid sh_entsize: expected " + Twine(sizeof(T)) + |
| ", but got " + Twine(Section->sh_entsize)); |
| size_t Pos = Section->sh_offset + Entry * sizeof(T); |
| if (Pos + sizeof(T) > Buf.size()) |
| return createError("unable to access section " + |
| getSecIndexForError(this, Section) + " data at 0x" + |
| Twine::utohexstr(Pos) + |
| ": offset goes past the end of file"); |
| return reinterpret_cast<const T *>(base() + Pos); |
| } |
| |
| template <class ELFT> |
| Expected<const typename ELFT::Shdr *> |
| ELFFile<ELFT>::getSection(uint32_t Index) const { |
| auto TableOrErr = sections(); |
| if (!TableOrErr) |
| return TableOrErr.takeError(); |
| return object::getSection<ELFT>(*TableOrErr, Index); |
| } |
| |
| template <class ELFT> |
| Expected<StringRef> |
| ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section, |
| WarningHandler WarnHandler) const { |
| if (Section->sh_type != ELF::SHT_STRTAB) |
| if (Error E = WarnHandler("invalid sh_type for string table section " + |
| getSecIndexForError(this, Section) + |
| ": expected SHT_STRTAB, but got " + |
| object::getELFSectionTypeName( |
| getHeader()->e_machine, Section->sh_type))) |
| return std::move(E); |
| |
| auto V = getSectionContentsAsArray<char>(Section); |
| if (!V) |
| return V.takeError(); |
| ArrayRef<char> Data = *V; |
| if (Data.empty()) |
| return createError("SHT_STRTAB string table section " + |
| getSecIndexForError(this, Section) + " is empty"); |
| if (Data.back() != '\0') |
| return createError("SHT_STRTAB string table section " + |
| getSecIndexForError(this, Section) + |
| " is non-null terminated"); |
| return StringRef(Data.begin(), Data.size()); |
| } |
| |
| template <class ELFT> |
| Expected<ArrayRef<typename ELFT::Word>> |
| ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section) const { |
| auto SectionsOrErr = sections(); |
| if (!SectionsOrErr) |
| return SectionsOrErr.takeError(); |
| return getSHNDXTable(Section, *SectionsOrErr); |
| } |
| |
| template <class ELFT> |
| Expected<ArrayRef<typename ELFT::Word>> |
| ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section, |
| Elf_Shdr_Range Sections) const { |
| assert(Section.sh_type == ELF::SHT_SYMTAB_SHNDX); |
| auto VOrErr = getSectionContentsAsArray<Elf_Word>(&Section); |
| if (!VOrErr) |
| return VOrErr.takeError(); |
| ArrayRef<Elf_Word> V = *VOrErr; |
| auto SymTableOrErr = object::getSection<ELFT>(Sections, Section.sh_link); |
| if (!SymTableOrErr) |
| return SymTableOrErr.takeError(); |
| const Elf_Shdr &SymTable = **SymTableOrErr; |
| if (SymTable.sh_type != ELF::SHT_SYMTAB && |
| SymTable.sh_type != ELF::SHT_DYNSYM) |
| return createError("SHT_SYMTAB_SHNDX section is linked with " + |
| object::getELFSectionTypeName(getHeader()->e_machine, |
| SymTable.sh_type) + |
| " section (expected SHT_SYMTAB/SHT_DYNSYM)"); |
| |
| uint64_t Syms = SymTable.sh_size / sizeof(Elf_Sym); |
| if (V.size() != Syms) |
| return createError("SHT_SYMTAB_SHNDX has " + Twine(V.size()) + |
| " entries, but the symbol table associated has " + |
| Twine(Syms)); |
| |
| return V; |
| } |
| |
| template <class ELFT> |
| Expected<StringRef> |
| ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec) const { |
| auto SectionsOrErr = sections(); |
| if (!SectionsOrErr) |
| return SectionsOrErr.takeError(); |
| return getStringTableForSymtab(Sec, *SectionsOrErr); |
| } |
| |
| template <class ELFT> |
| Expected<StringRef> |
| ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec, |
| Elf_Shdr_Range Sections) const { |
| |
| if (Sec.sh_type != ELF::SHT_SYMTAB && Sec.sh_type != ELF::SHT_DYNSYM) |
| // TODO: this error is untested. |
| return createError( |
| "invalid sh_type for symbol table, expected SHT_SYMTAB or SHT_DYNSYM"); |
| auto SectionOrErr = object::getSection<ELFT>(Sections, Sec.sh_link); |
| if (!SectionOrErr) |
| return SectionOrErr.takeError(); |
| return getStringTable(*SectionOrErr); |
| } |
| |
| template <class ELFT> |
| Expected<StringRef> |
| ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section, |
| WarningHandler WarnHandler) const { |
| auto SectionsOrErr = sections(); |
| if (!SectionsOrErr) |
| return SectionsOrErr.takeError(); |
| auto Table = getSectionStringTable(*SectionsOrErr, WarnHandler); |
| if (!Table) |
| return Table.takeError(); |
| return getSectionName(Section, *Table); |
| } |
| |
| template <class ELFT> |
| Expected<StringRef> ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section, |
| StringRef DotShstrtab) const { |
| uint32_t Offset = Section->sh_name; |
| if (Offset == 0) |
| return StringRef(); |
| if (Offset >= DotShstrtab.size()) |
| return createError("a section " + getSecIndexForError(this, Section) + |
| " has an invalid sh_name (0x" + |
| Twine::utohexstr(Offset) + |
| ") offset which goes past the end of the " |
| "section name string table"); |
| return StringRef(DotShstrtab.data() + Offset); |
| } |
| |
| /// This function returns the hash value for a symbol in the .dynsym section |
| /// Name of the API remains consistent as specified in the libelf |
| /// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash |
| inline unsigned hashSysV(StringRef SymbolName) { |
| unsigned h = 0, g; |
| for (char C : SymbolName) { |
| h = (h << 4) + C; |
| g = h & 0xf0000000L; |
| if (g != 0) |
| h ^= g >> 24; |
| h &= ~g; |
| } |
| return h; |
| } |
| |
| } // end namespace object |
| } // end namespace llvm |
| |
| #endif // LLVM_OBJECT_ELF_H |
