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llvm-mirror/include/llvm/Object/ELF.h
Igor Kudrin 9a3f5f5cf9 [llvm-readobj/ELF] Print GNU Hash section
Add a new command line switch, -gnu-hash-table, to print the content of that section.

Differential Revision: http://reviews.llvm.org/D13696

llvm-svn: 250291
2015-10-14 12:11:50 +00:00

543 lines
18 KiB
C++

//===- ELF.h - ELF object file implementation -------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the ELFFile template class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_OBJECT_ELF_H
#define LLVM_OBJECT_ELF_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/Object/ELFTypes.h"
#include "llvm/Support/MemoryBuffer.h"
namespace llvm {
namespace object {
StringRef getELFRelocationTypeName(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]);
}
template <class ELFT>
class ELFFile {
public:
LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
typedef typename std::conditional<ELFT::Is64Bits,
uint64_t, uint32_t>::type uintX_t;
typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
typedef Elf_Sym_Impl<ELFT> Elf_Sym;
typedef Elf_Dyn_Impl<ELFT> Elf_Dyn;
typedef Elf_Phdr_Impl<ELFT> Elf_Phdr;
typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
typedef Elf_Verdef_Impl<ELFT> Elf_Verdef;
typedef Elf_Verdaux_Impl<ELFT> Elf_Verdaux;
typedef Elf_Verneed_Impl<ELFT> Elf_Verneed;
typedef Elf_Vernaux_Impl<ELFT> Elf_Vernaux;
typedef Elf_Versym_Impl<ELFT> Elf_Versym;
typedef Elf_Hash_Impl<ELFT> Elf_Hash;
typedef Elf_GnuHash_Impl<ELFT> Elf_GnuHash;
typedef iterator_range<const Elf_Dyn *> Elf_Dyn_Range;
typedef iterator_range<const Elf_Shdr *> Elf_Shdr_Range;
typedef iterator_range<const Elf_Sym *> Elf_Sym_Range;
const uint8_t *base() const {
return reinterpret_cast<const uint8_t *>(Buf.data());
}
private:
StringRef Buf;
const Elf_Ehdr *Header;
const Elf_Shdr *SectionHeaderTable = nullptr;
StringRef DotShstrtab; // Section header string table.
public:
template<typename T>
const T *getEntry(uint32_t Section, uint32_t Entry) const;
template <typename T>
const T *getEntry(const Elf_Shdr *Section, uint32_t Entry) const;
ErrorOr<StringRef> getStringTable(const Elf_Shdr *Section) const;
ErrorOr<StringRef> getStringTableForSymtab(const Elf_Shdr &Section) const;
ErrorOr<ArrayRef<Elf_Word>> getSHNDXTable(const Elf_Shdr &Section) const;
void VerifyStrTab(const Elf_Shdr *sh) const;
StringRef getRelocationTypeName(uint32_t Type) const;
void getRelocationTypeName(uint32_t Type,
SmallVectorImpl<char> &Result) const;
/// \brief Get the symbol for a given relocation.
const Elf_Sym *getRelocationSymbol(const Elf_Rel *Rel,
const Elf_Shdr *SymTab) const;
ELFFile(StringRef Object, std::error_code &EC);
bool isMipsELF64() const {
return Header->e_machine == ELF::EM_MIPS &&
Header->getFileClass() == ELF::ELFCLASS64;
}
bool isMips64EL() const {
return Header->e_machine == ELF::EM_MIPS &&
Header->getFileClass() == ELF::ELFCLASS64 &&
Header->getDataEncoding() == ELF::ELFDATA2LSB;
}
ErrorOr<const Elf_Dyn *> dynamic_table_begin(const Elf_Phdr *Phdr) const;
ErrorOr<const Elf_Dyn *> dynamic_table_end(const Elf_Phdr *Phdr) const;
ErrorOr<Elf_Dyn_Range> dynamic_table(const Elf_Phdr *Phdr) const {
ErrorOr<const Elf_Dyn *> Begin = dynamic_table_begin(Phdr);
if (std::error_code EC = Begin.getError())
return EC;
ErrorOr<const Elf_Dyn *> End = dynamic_table_end(Phdr);
if (std::error_code EC = End.getError())
return EC;
return make_range(*Begin, *End);
}
const Elf_Shdr *section_begin() const;
const Elf_Shdr *section_end() const;
Elf_Shdr_Range sections() const {
return make_range(section_begin(), section_end());
}
const Elf_Sym *symbol_begin(const Elf_Shdr *Sec) const {
if (!Sec)
return nullptr;
if (Sec->sh_entsize != sizeof(Elf_Sym))
report_fatal_error("Invalid symbol size");
return reinterpret_cast<const Elf_Sym *>(base() + Sec->sh_offset);
}
const Elf_Sym *symbol_end(const Elf_Shdr *Sec) const {
if (!Sec)
return nullptr;
uint64_t Size = Sec->sh_size;
if (Size % sizeof(Elf_Sym))
report_fatal_error("Invalid symbol table size");
return symbol_begin(Sec) + Size / sizeof(Elf_Sym);
}
Elf_Sym_Range symbols(const Elf_Shdr *Sec) const {
return make_range(symbol_begin(Sec), symbol_end(Sec));
}
typedef iterator_range<const Elf_Rela *> Elf_Rela_Range;
const Elf_Rela *rela_begin(const Elf_Shdr *sec) const {
if (sec->sh_entsize != sizeof(Elf_Rela))
report_fatal_error("Invalid relocation entry size");
return reinterpret_cast<const Elf_Rela *>(base() + sec->sh_offset);
}
const Elf_Rela *rela_end(const Elf_Shdr *sec) const {
uint64_t Size = sec->sh_size;
if (Size % sizeof(Elf_Rela))
report_fatal_error("Invalid relocation table size");
return rela_begin(sec) + Size / sizeof(Elf_Rela);
}
Elf_Rela_Range relas(const Elf_Shdr *Sec) const {
return make_range(rela_begin(Sec), rela_end(Sec));
}
const Elf_Rel *rel_begin(const Elf_Shdr *sec) const {
if (sec->sh_entsize != sizeof(Elf_Rel))
report_fatal_error("Invalid relocation entry size");
return reinterpret_cast<const Elf_Rel *>(base() + sec->sh_offset);
}
const Elf_Rel *rel_end(const Elf_Shdr *sec) const {
uint64_t Size = sec->sh_size;
if (Size % sizeof(Elf_Rel))
report_fatal_error("Invalid relocation table size");
return rel_begin(sec) + Size / sizeof(Elf_Rel);
}
typedef iterator_range<const Elf_Rel *> Elf_Rel_Range;
Elf_Rel_Range rels(const Elf_Shdr *Sec) const {
return make_range(rel_begin(Sec), rel_end(Sec));
}
/// \brief Iterate over program header table.
const Elf_Phdr *program_header_begin() const {
if (Header->e_phnum && Header->e_phentsize != sizeof(Elf_Phdr))
report_fatal_error("Invalid program header size");
return reinterpret_cast<const Elf_Phdr *>(base() + Header->e_phoff);
}
const Elf_Phdr *program_header_end() const {
return program_header_begin() + Header->e_phnum;
}
typedef iterator_range<const Elf_Phdr *> Elf_Phdr_Range;
const Elf_Phdr_Range program_headers() const {
return make_range(program_header_begin(), program_header_end());
}
uint64_t getNumSections() const;
uintX_t getStringTableIndex() const;
uint32_t getExtendedSymbolTableIndex(const Elf_Sym *Sym,
const Elf_Shdr *SymTab,
ArrayRef<Elf_Word> ShndxTable) const;
const Elf_Ehdr *getHeader() const { return Header; }
ErrorOr<const Elf_Shdr *> getSection(const Elf_Sym *Sym,
const Elf_Shdr *SymTab,
ArrayRef<Elf_Word> ShndxTable) const;
ErrorOr<const Elf_Shdr *> getSection(uint32_t Index) const;
const Elf_Sym *getSymbol(const Elf_Shdr *Sec, uint32_t Index) const {
return &*(symbol_begin(Sec) + Index);
}
ErrorOr<StringRef> getSectionName(const Elf_Shdr *Section) const;
template <typename T>
ErrorOr<ArrayRef<T>> getSectionContentsAsArray(const Elf_Shdr *Sec) const;
ErrorOr<ArrayRef<uint8_t> > getSectionContents(const Elf_Shdr *Sec) const;
};
typedef ELFFile<ELFType<support::little, false>> ELF32LEFile;
typedef ELFFile<ELFType<support::little, true>> ELF64LEFile;
typedef ELFFile<ELFType<support::big, false>> ELF32BEFile;
typedef ELFFile<ELFType<support::big, true>> ELF64BEFile;
template <class ELFT>
uint32_t ELFFile<ELFT>::getExtendedSymbolTableIndex(
const Elf_Sym *Sym, const Elf_Shdr *SymTab,
ArrayRef<Elf_Word> ShndxTable) const {
assert(Sym->st_shndx == ELF::SHN_XINDEX);
unsigned Index = Sym - symbol_begin(SymTab);
// The size of the table was checked in getSHNDXTable.
return ShndxTable[Index];
}
template <class ELFT>
ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
ELFFile<ELFT>::getSection(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
ArrayRef<Elf_Word> ShndxTable) const {
uint32_t Index = Sym->st_shndx;
if (Index == ELF::SHN_XINDEX)
return getSection(getExtendedSymbolTableIndex(Sym, SymTab, ShndxTable));
if (Index == ELF::SHN_UNDEF || Index >= ELF::SHN_LORESERVE)
return nullptr;
return getSection(Sym->st_shndx);
}
template <class ELFT>
template <typename T>
ErrorOr<ArrayRef<T>>
ELFFile<ELFT>::getSectionContentsAsArray(const Elf_Shdr *Sec) const {
uintX_t Offset = Sec->sh_offset;
uintX_t Size = Sec->sh_size;
if (Size % sizeof(T))
return object_error::parse_failed;
if (Offset + Size > Buf.size())
return object_error::parse_failed;
const T *Start = reinterpret_cast<const T *>(base() + Offset);
return makeArrayRef(Start, Size / sizeof(T));
}
template <class ELFT>
ErrorOr<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(Header->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>
const typename ELFFile<ELFT>::Elf_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>
uint64_t ELFFile<ELFT>::getNumSections() const {
assert(Header && "Header not initialized!");
if (Header->e_shnum == ELF::SHN_UNDEF && Header->e_shoff > 0) {
assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
return SectionHeaderTable->sh_size;
}
return Header->e_shnum;
}
template <class ELFT>
typename ELFFile<ELFT>::uintX_t ELFFile<ELFT>::getStringTableIndex() const {
if (Header->e_shnum == ELF::SHN_UNDEF) {
if (Header->e_shstrndx == ELF::SHN_HIRESERVE)
return SectionHeaderTable->sh_link;
if (Header->e_shstrndx >= getNumSections())
return 0;
}
return Header->e_shstrndx;
}
template <class ELFT>
ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
: Buf(Object) {
const uint64_t FileSize = Buf.size();
if (sizeof(Elf_Ehdr) > FileSize) {
// File too short!
EC = object_error::parse_failed;
return;
}
Header = reinterpret_cast<const Elf_Ehdr *>(base());
if (Header->e_shoff == 0)
return;
const uint64_t SectionTableOffset = Header->e_shoff;
if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize) {
// Section header table goes past end of file!
EC = object_error::parse_failed;
return;
}
// The getNumSections() call below depends on SectionHeaderTable being set.
SectionHeaderTable =
reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);
const uint64_t SectionTableSize = getNumSections() * Header->e_shentsize;
if (SectionTableOffset + SectionTableSize > FileSize) {
// Section table goes past end of file!
EC = object_error::parse_failed;
return;
}
// Get string table sections.
uintX_t StringTableIndex = getStringTableIndex();
if (StringTableIndex) {
ErrorOr<const Elf_Shdr *> StrTabSecOrErr = getSection(StringTableIndex);
if ((EC = StrTabSecOrErr.getError()))
return;
ErrorOr<StringRef> StringTableOrErr = getStringTable(*StrTabSecOrErr);
if ((EC = StringTableOrErr.getError()))
return;
DotShstrtab = *StringTableOrErr;
}
EC = std::error_code();
}
template <class ELFT>
static bool compareAddr(uint64_t VAddr, const Elf_Phdr_Impl<ELFT> *Phdr) {
return VAddr < Phdr->p_vaddr;
}
template <class ELFT>
const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_begin() const {
if (Header->e_shentsize != sizeof(Elf_Shdr))
report_fatal_error(
"Invalid section header entry size (e_shentsize) in ELF header");
return reinterpret_cast<const Elf_Shdr *>(base() + Header->e_shoff);
}
template <class ELFT>
const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_end() const {
return section_begin() + getNumSections();
}
template <class ELFT>
ErrorOr<const typename ELFFile<ELFT>::Elf_Dyn *>
ELFFile<ELFT>::dynamic_table_begin(const Elf_Phdr *Phdr) const {
if (!Phdr)
return nullptr;
assert(Phdr->p_type == ELF::PT_DYNAMIC && "Got the wrong program header");
uintX_t Offset = Phdr->p_offset;
if (Offset > Buf.size())
return object_error::parse_failed;
return reinterpret_cast<const Elf_Dyn *>(base() + Offset);
}
template <class ELFT>
ErrorOr<const typename ELFFile<ELFT>::Elf_Dyn *>
ELFFile<ELFT>::dynamic_table_end(const Elf_Phdr *Phdr) const {
if (!Phdr)
return nullptr;
assert(Phdr->p_type == ELF::PT_DYNAMIC && "Got the wrong program header");
uintX_t Size = Phdr->p_filesz;
if (Size % sizeof(Elf_Dyn))
return object_error::elf_invalid_dynamic_table_size;
// FIKME: Check for overflow?
uintX_t End = Phdr->p_offset + Size;
if (End > Buf.size())
return object_error::parse_failed;
return reinterpret_cast<const Elf_Dyn *>(base() + End);
}
template <class ELFT>
template <typename T>
const T *ELFFile<ELFT>::getEntry(uint32_t Section, uint32_t Entry) const {
ErrorOr<const Elf_Shdr *> Sec = getSection(Section);
if (std::error_code EC = Sec.getError())
report_fatal_error(EC.message());
return getEntry<T>(*Sec, Entry);
}
template <class ELFT>
template <typename T>
const T *ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
uint32_t Entry) const {
return reinterpret_cast<const T *>(base() + Section->sh_offset +
(Entry * Section->sh_entsize));
}
template <class ELFT>
ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
ELFFile<ELFT>::getSection(uint32_t Index) const {
assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
if (Index >= getNumSections())
return object_error::invalid_section_index;
return reinterpret_cast<const Elf_Shdr *>(
reinterpret_cast<const char *>(SectionHeaderTable) +
(Index * Header->e_shentsize));
}
template <class ELFT>
ErrorOr<StringRef>
ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
if (Section->sh_type != ELF::SHT_STRTAB)
return object_error::parse_failed;
uint64_t Offset = Section->sh_offset;
uint64_t Size = Section->sh_size;
if (Offset + Size > Buf.size())
return object_error::parse_failed;
StringRef Data((const char *)base() + Section->sh_offset, Size);
if (Data[Size - 1] != '\0')
return object_error::string_table_non_null_end;
return Data;
}
template <class ELFT>
ErrorOr<ArrayRef<typename ELFFile<ELFT>::Elf_Word>>
ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section) const {
assert(Section.sh_type == ELF::SHT_SYMTAB_SHNDX);
const Elf_Word *ShndxTableBegin =
reinterpret_cast<const Elf_Word *>(base() + Section.sh_offset);
uintX_t Size = Section.sh_size;
if (Size % sizeof(uint32_t))
return object_error::parse_failed;
uintX_t NumSymbols = Size / sizeof(uint32_t);
const Elf_Word *ShndxTableEnd = ShndxTableBegin + NumSymbols;
if (reinterpret_cast<const char *>(ShndxTableEnd) > Buf.end())
return object_error::parse_failed;
ErrorOr<const Elf_Shdr *> SymTableOrErr = getSection(Section.sh_link);
if (std::error_code EC = SymTableOrErr.getError())
return EC;
const Elf_Shdr &SymTable = **SymTableOrErr;
if (SymTable.sh_type != ELF::SHT_SYMTAB &&
SymTable.sh_type != ELF::SHT_DYNSYM)
return object_error::parse_failed;
if (NumSymbols != (SymTable.sh_size / sizeof(Elf_Sym)))
return object_error::parse_failed;
return makeArrayRef(ShndxTableBegin, ShndxTableEnd);
}
template <class ELFT>
ErrorOr<StringRef>
ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec) const {
if (Sec.sh_type != ELF::SHT_SYMTAB && Sec.sh_type != ELF::SHT_DYNSYM)
return object_error::parse_failed;
ErrorOr<const Elf_Shdr *> SectionOrErr = getSection(Sec.sh_link);
if (std::error_code EC = SectionOrErr.getError())
return EC;
return getStringTable(*SectionOrErr);
}
template <class ELFT>
ErrorOr<StringRef>
ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
uint32_t Offset = Section->sh_name;
if (Offset == 0)
return StringRef();
if (Offset >= DotShstrtab.size())
return object_error::parse_failed;
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
static inline unsigned elf_hash(StringRef &symbolName) {
unsigned h = 0, g;
for (unsigned i = 0, j = symbolName.size(); i < j; i++) {
h = (h << 4) + symbolName[i];
g = h & 0xf0000000L;
if (g != 0)
h ^= g >> 24;
h &= ~g;
}
return h;
}
} // end namespace object
} // end namespace llvm
#endif