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ObjectFileELF.cpp
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ObjectFileELF.cpp
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//===-- ObjectFileELF.cpp -------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "ObjectFileELF.h"
#include <algorithm>
#include <cassert>
#include <unordered_map>
#include "lldb/Core/FileSpecList.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Progress.h"
#include "lldb/Core/Section.h"
#include "lldb/Host/FileSystem.h"
#include "lldb/Host/LZMA.h"
#include "lldb/Symbol/DWARFCallFrameInfo.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/ArchSpec.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/RangeMap.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/Stream.h"
#include "lldb/Utility/Timer.h"
#include "llvm/ADT/IntervalMap.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/Object/Decompressor.h"
#include "llvm/Support/ARMBuildAttributes.h"
#include "llvm/Support/CRC.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/MipsABIFlags.h"
#define CASE_AND_STREAM(s, def, width) \
case def: \
s->Printf("%-*s", width, #def); \
break;
using namespace lldb;
using namespace lldb_private;
using namespace elf;
using namespace llvm::ELF;
LLDB_PLUGIN_DEFINE(ObjectFileELF)
namespace {
// ELF note owner definitions
const char *const LLDB_NT_OWNER_FREEBSD = "FreeBSD";
const char *const LLDB_NT_OWNER_GNU = "GNU";
const char *const LLDB_NT_OWNER_NETBSD = "NetBSD";
const char *const LLDB_NT_OWNER_NETBSDCORE = "NetBSD-CORE";
const char *const LLDB_NT_OWNER_OPENBSD = "OpenBSD";
const char *const LLDB_NT_OWNER_ANDROID = "Android";
const char *const LLDB_NT_OWNER_CORE = "CORE";
const char *const LLDB_NT_OWNER_LINUX = "LINUX";
// ELF note type definitions
const elf_word LLDB_NT_FREEBSD_ABI_TAG = 0x01;
const elf_word LLDB_NT_FREEBSD_ABI_SIZE = 4;
const elf_word LLDB_NT_GNU_ABI_TAG = 0x01;
const elf_word LLDB_NT_GNU_ABI_SIZE = 16;
const elf_word LLDB_NT_GNU_BUILD_ID_TAG = 0x03;
const elf_word LLDB_NT_NETBSD_IDENT_TAG = 1;
const elf_word LLDB_NT_NETBSD_IDENT_DESCSZ = 4;
const elf_word LLDB_NT_NETBSD_IDENT_NAMESZ = 7;
const elf_word LLDB_NT_NETBSD_PROCINFO = 1;
// GNU ABI note OS constants
const elf_word LLDB_NT_GNU_ABI_OS_LINUX = 0x00;
const elf_word LLDB_NT_GNU_ABI_OS_HURD = 0x01;
const elf_word LLDB_NT_GNU_ABI_OS_SOLARIS = 0x02;
//===----------------------------------------------------------------------===//
/// \class ELFRelocation
/// Generic wrapper for ELFRel and ELFRela.
///
/// This helper class allows us to parse both ELFRel and ELFRela relocation
/// entries in a generic manner.
class ELFRelocation {
public:
/// Constructs an ELFRelocation entry with a personality as given by @p
/// type.
///
/// \param type Either DT_REL or DT_RELA. Any other value is invalid.
ELFRelocation(unsigned type);
~ELFRelocation();
bool Parse(const lldb_private::DataExtractor &data, lldb::offset_t *offset);
static unsigned RelocType32(const ELFRelocation &rel);
static unsigned RelocType64(const ELFRelocation &rel);
static unsigned RelocSymbol32(const ELFRelocation &rel);
static unsigned RelocSymbol64(const ELFRelocation &rel);
static unsigned RelocOffset32(const ELFRelocation &rel);
static unsigned RelocOffset64(const ELFRelocation &rel);
static unsigned RelocAddend32(const ELFRelocation &rel);
static unsigned RelocAddend64(const ELFRelocation &rel);
private:
typedef llvm::PointerUnion<ELFRel *, ELFRela *> RelocUnion;
RelocUnion reloc;
};
ELFRelocation::ELFRelocation(unsigned type) {
if (type == DT_REL || type == SHT_REL)
reloc = new ELFRel();
else if (type == DT_RELA || type == SHT_RELA)
reloc = new ELFRela();
else {
assert(false && "unexpected relocation type");
reloc = static_cast<ELFRel *>(nullptr);
}
}
ELFRelocation::~ELFRelocation() {
if (reloc.is<ELFRel *>())
delete reloc.get<ELFRel *>();
else
delete reloc.get<ELFRela *>();
}
bool ELFRelocation::Parse(const lldb_private::DataExtractor &data,
lldb::offset_t *offset) {
if (reloc.is<ELFRel *>())
return reloc.get<ELFRel *>()->Parse(data, offset);
else
return reloc.get<ELFRela *>()->Parse(data, offset);
}
unsigned ELFRelocation::RelocType32(const ELFRelocation &rel) {
if (rel.reloc.is<ELFRel *>())
return ELFRel::RelocType32(*rel.reloc.get<ELFRel *>());
else
return ELFRela::RelocType32(*rel.reloc.get<ELFRela *>());
}
unsigned ELFRelocation::RelocType64(const ELFRelocation &rel) {
if (rel.reloc.is<ELFRel *>())
return ELFRel::RelocType64(*rel.reloc.get<ELFRel *>());
else
return ELFRela::RelocType64(*rel.reloc.get<ELFRela *>());
}
unsigned ELFRelocation::RelocSymbol32(const ELFRelocation &rel) {
if (rel.reloc.is<ELFRel *>())
return ELFRel::RelocSymbol32(*rel.reloc.get<ELFRel *>());
else
return ELFRela::RelocSymbol32(*rel.reloc.get<ELFRela *>());
}
unsigned ELFRelocation::RelocSymbol64(const ELFRelocation &rel) {
if (rel.reloc.is<ELFRel *>())
return ELFRel::RelocSymbol64(*rel.reloc.get<ELFRel *>());
else
return ELFRela::RelocSymbol64(*rel.reloc.get<ELFRela *>());
}
unsigned ELFRelocation::RelocOffset32(const ELFRelocation &rel) {
if (rel.reloc.is<ELFRel *>())
return rel.reloc.get<ELFRel *>()->r_offset;
else
return rel.reloc.get<ELFRela *>()->r_offset;
}
unsigned ELFRelocation::RelocOffset64(const ELFRelocation &rel) {
if (rel.reloc.is<ELFRel *>())
return rel.reloc.get<ELFRel *>()->r_offset;
else
return rel.reloc.get<ELFRela *>()->r_offset;
}
unsigned ELFRelocation::RelocAddend32(const ELFRelocation &rel) {
if (rel.reloc.is<ELFRel *>())
return 0;
else
return rel.reloc.get<ELFRela *>()->r_addend;
}
unsigned ELFRelocation::RelocAddend64(const ELFRelocation &rel) {
if (rel.reloc.is<ELFRel *>())
return 0;
else
return rel.reloc.get<ELFRela *>()->r_addend;
}
} // end anonymous namespace
static user_id_t SegmentID(size_t PHdrIndex) {
return ~user_id_t(PHdrIndex);
}
bool ELFNote::Parse(const DataExtractor &data, lldb::offset_t *offset) {
// Read all fields.
if (data.GetU32(offset, &n_namesz, 3) == nullptr)
return false;
// The name field is required to be nul-terminated, and n_namesz includes the
// terminating nul in observed implementations (contrary to the ELF-64 spec).
// A special case is needed for cores generated by some older Linux versions,
// which write a note named "CORE" without a nul terminator and n_namesz = 4.
if (n_namesz == 4) {
char buf[4];
if (data.ExtractBytes(*offset, 4, data.GetByteOrder(), buf) != 4)
return false;
if (strncmp(buf, "CORE", 4) == 0) {
n_name = "CORE";
*offset += 4;
return true;
}
}
const char *cstr = data.GetCStr(offset, llvm::alignTo(n_namesz, 4));
if (cstr == nullptr) {
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYMBOLS));
LLDB_LOGF(log, "Failed to parse note name lacking nul terminator");
return false;
}
n_name = cstr;
return true;
}
static uint32_t mipsVariantFromElfFlags (const elf::ELFHeader &header) {
const uint32_t mips_arch = header.e_flags & llvm::ELF::EF_MIPS_ARCH;
uint32_t endian = header.e_ident[EI_DATA];
uint32_t arch_variant = ArchSpec::eMIPSSubType_unknown;
uint32_t fileclass = header.e_ident[EI_CLASS];
// If there aren't any elf flags available (e.g core elf file) then return
// default
// 32 or 64 bit arch (without any architecture revision) based on object file's class.
if (header.e_type == ET_CORE) {
switch (fileclass) {
case llvm::ELF::ELFCLASS32:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips32el
: ArchSpec::eMIPSSubType_mips32;
case llvm::ELF::ELFCLASS64:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips64el
: ArchSpec::eMIPSSubType_mips64;
default:
return arch_variant;
}
}
switch (mips_arch) {
case llvm::ELF::EF_MIPS_ARCH_1:
case llvm::ELF::EF_MIPS_ARCH_2:
case llvm::ELF::EF_MIPS_ARCH_32:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips32el
: ArchSpec::eMIPSSubType_mips32;
case llvm::ELF::EF_MIPS_ARCH_32R2:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips32r2el
: ArchSpec::eMIPSSubType_mips32r2;
case llvm::ELF::EF_MIPS_ARCH_32R6:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips32r6el
: ArchSpec::eMIPSSubType_mips32r6;
case llvm::ELF::EF_MIPS_ARCH_3:
case llvm::ELF::EF_MIPS_ARCH_4:
case llvm::ELF::EF_MIPS_ARCH_5:
case llvm::ELF::EF_MIPS_ARCH_64:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips64el
: ArchSpec::eMIPSSubType_mips64;
case llvm::ELF::EF_MIPS_ARCH_64R2:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips64r2el
: ArchSpec::eMIPSSubType_mips64r2;
case llvm::ELF::EF_MIPS_ARCH_64R6:
return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips64r6el
: ArchSpec::eMIPSSubType_mips64r6;
default:
break;
}
return arch_variant;
}
static uint32_t riscvVariantFromElfFlags(const elf::ELFHeader &header) {
uint32_t fileclass = header.e_ident[EI_CLASS];
switch (fileclass) {
case llvm::ELF::ELFCLASS32:
return ArchSpec::eRISCVSubType_riscv32;
case llvm::ELF::ELFCLASS64:
return ArchSpec::eRISCVSubType_riscv64;
default:
return ArchSpec::eRISCVSubType_unknown;
}
}
static uint32_t subTypeFromElfHeader(const elf::ELFHeader &header) {
if (header.e_machine == llvm::ELF::EM_MIPS)
return mipsVariantFromElfFlags(header);
else if (header.e_machine == llvm::ELF::EM_RISCV)
return riscvVariantFromElfFlags(header);
return LLDB_INVALID_CPUTYPE;
}
char ObjectFileELF::ID;
// Arbitrary constant used as UUID prefix for core files.
const uint32_t ObjectFileELF::g_core_uuid_magic(0xE210C);
// Static methods.
void ObjectFileELF::Initialize() {
PluginManager::RegisterPlugin(GetPluginNameStatic(),
GetPluginDescriptionStatic(), CreateInstance,
CreateMemoryInstance, GetModuleSpecifications);
}
void ObjectFileELF::Terminate() {
PluginManager::UnregisterPlugin(CreateInstance);
}
lldb_private::ConstString ObjectFileELF::GetPluginNameStatic() {
static ConstString g_name("elf");
return g_name;
}
const char *ObjectFileELF::GetPluginDescriptionStatic() {
return "ELF object file reader.";
}
ObjectFile *ObjectFileELF::CreateInstance(const lldb::ModuleSP &module_sp,
DataBufferSP &data_sp,
lldb::offset_t data_offset,
const lldb_private::FileSpec *file,
lldb::offset_t file_offset,
lldb::offset_t length) {
if (!data_sp) {
data_sp = MapFileData(*file, length, file_offset);
if (!data_sp)
return nullptr;
data_offset = 0;
}
assert(data_sp);
if (data_sp->GetByteSize() <= (llvm::ELF::EI_NIDENT + data_offset))
return nullptr;
const uint8_t *magic = data_sp->GetBytes() + data_offset;
if (!ELFHeader::MagicBytesMatch(magic))
return nullptr;
// Update the data to contain the entire file if it doesn't already
if (data_sp->GetByteSize() < length) {
data_sp = MapFileData(*file, length, file_offset);
if (!data_sp)
return nullptr;
data_offset = 0;
magic = data_sp->GetBytes();
}
unsigned address_size = ELFHeader::AddressSizeInBytes(magic);
if (address_size == 4 || address_size == 8) {
std::unique_ptr<ObjectFileELF> objfile_up(new ObjectFileELF(
module_sp, data_sp, data_offset, file, file_offset, length));
ArchSpec spec = objfile_up->GetArchitecture();
if (spec && objfile_up->SetModulesArchitecture(spec))
return objfile_up.release();
}
return nullptr;
}
ObjectFile *ObjectFileELF::CreateMemoryInstance(
const lldb::ModuleSP &module_sp, DataBufferSP &data_sp,
const lldb::ProcessSP &process_sp, lldb::addr_t header_addr) {
if (data_sp && data_sp->GetByteSize() > (llvm::ELF::EI_NIDENT)) {
const uint8_t *magic = data_sp->GetBytes();
if (ELFHeader::MagicBytesMatch(magic)) {
unsigned address_size = ELFHeader::AddressSizeInBytes(magic);
if (address_size == 4 || address_size == 8) {
std::unique_ptr<ObjectFileELF> objfile_up(
new ObjectFileELF(module_sp, data_sp, process_sp, header_addr));
ArchSpec spec = objfile_up->GetArchitecture();
if (spec && objfile_up->SetModulesArchitecture(spec))
return objfile_up.release();
}
}
}
return nullptr;
}
bool ObjectFileELF::MagicBytesMatch(DataBufferSP &data_sp,
lldb::addr_t data_offset,
lldb::addr_t data_length) {
if (data_sp &&
data_sp->GetByteSize() > (llvm::ELF::EI_NIDENT + data_offset)) {
const uint8_t *magic = data_sp->GetBytes() + data_offset;
return ELFHeader::MagicBytesMatch(magic);
}
return false;
}
static uint32_t calc_crc32(uint32_t init, const DataExtractor &data) {
return llvm::crc32(
init, llvm::makeArrayRef(data.GetDataStart(), data.GetByteSize()));
}
uint32_t ObjectFileELF::CalculateELFNotesSegmentsCRC32(
const ProgramHeaderColl &program_headers, DataExtractor &object_data) {
uint32_t core_notes_crc = 0;
for (const ELFProgramHeader &H : program_headers) {
if (H.p_type == llvm::ELF::PT_NOTE) {
const elf_off ph_offset = H.p_offset;
const size_t ph_size = H.p_filesz;
DataExtractor segment_data;
if (segment_data.SetData(object_data, ph_offset, ph_size) != ph_size) {
// The ELF program header contained incorrect data, probably corefile
// is incomplete or corrupted.
break;
}
core_notes_crc = calc_crc32(core_notes_crc, segment_data);
}
}
return core_notes_crc;
}
static const char *OSABIAsCString(unsigned char osabi_byte) {
#define _MAKE_OSABI_CASE(x) \
case x: \
return #x
switch (osabi_byte) {
_MAKE_OSABI_CASE(ELFOSABI_NONE);
_MAKE_OSABI_CASE(ELFOSABI_HPUX);
_MAKE_OSABI_CASE(ELFOSABI_NETBSD);
_MAKE_OSABI_CASE(ELFOSABI_GNU);
_MAKE_OSABI_CASE(ELFOSABI_HURD);
_MAKE_OSABI_CASE(ELFOSABI_SOLARIS);
_MAKE_OSABI_CASE(ELFOSABI_AIX);
_MAKE_OSABI_CASE(ELFOSABI_IRIX);
_MAKE_OSABI_CASE(ELFOSABI_FREEBSD);
_MAKE_OSABI_CASE(ELFOSABI_TRU64);
_MAKE_OSABI_CASE(ELFOSABI_MODESTO);
_MAKE_OSABI_CASE(ELFOSABI_OPENBSD);
_MAKE_OSABI_CASE(ELFOSABI_OPENVMS);
_MAKE_OSABI_CASE(ELFOSABI_NSK);
_MAKE_OSABI_CASE(ELFOSABI_AROS);
_MAKE_OSABI_CASE(ELFOSABI_FENIXOS);
_MAKE_OSABI_CASE(ELFOSABI_C6000_ELFABI);
_MAKE_OSABI_CASE(ELFOSABI_C6000_LINUX);
_MAKE_OSABI_CASE(ELFOSABI_ARM);
_MAKE_OSABI_CASE(ELFOSABI_STANDALONE);
default:
return "<unknown-osabi>";
}
#undef _MAKE_OSABI_CASE
}
//
// WARNING : This function is being deprecated
// It's functionality has moved to ArchSpec::SetArchitecture This function is
// only being kept to validate the move.
//
// TODO : Remove this function
static bool GetOsFromOSABI(unsigned char osabi_byte,
llvm::Triple::OSType &ostype) {
switch (osabi_byte) {
case ELFOSABI_AIX:
ostype = llvm::Triple::OSType::AIX;
break;
case ELFOSABI_FREEBSD:
ostype = llvm::Triple::OSType::FreeBSD;
break;
case ELFOSABI_GNU:
ostype = llvm::Triple::OSType::Linux;
break;
case ELFOSABI_NETBSD:
ostype = llvm::Triple::OSType::NetBSD;
break;
case ELFOSABI_OPENBSD:
ostype = llvm::Triple::OSType::OpenBSD;
break;
case ELFOSABI_SOLARIS:
ostype = llvm::Triple::OSType::Solaris;
break;
default:
ostype = llvm::Triple::OSType::UnknownOS;
}
return ostype != llvm::Triple::OSType::UnknownOS;
}
size_t ObjectFileELF::GetModuleSpecifications(
const lldb_private::FileSpec &file, lldb::DataBufferSP &data_sp,
lldb::offset_t data_offset, lldb::offset_t file_offset,
lldb::offset_t length, lldb_private::ModuleSpecList &specs) {
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_MODULES));
const size_t initial_count = specs.GetSize();
if (ObjectFileELF::MagicBytesMatch(data_sp, 0, data_sp->GetByteSize())) {
DataExtractor data;
data.SetData(data_sp);
elf::ELFHeader header;
lldb::offset_t header_offset = data_offset;
if (header.Parse(data, &header_offset)) {
if (data_sp) {
ModuleSpec spec(file);
const uint32_t sub_type = subTypeFromElfHeader(header);
spec.GetArchitecture().SetArchitecture(
eArchTypeELF, header.e_machine, sub_type, header.e_ident[EI_OSABI]);
if (spec.GetArchitecture().IsValid()) {
llvm::Triple::OSType ostype;
llvm::Triple::VendorType vendor;
llvm::Triple::OSType spec_ostype =
spec.GetArchitecture().GetTriple().getOS();
LLDB_LOGF(log, "ObjectFileELF::%s file '%s' module OSABI: %s",
__FUNCTION__, file.GetPath().c_str(),
OSABIAsCString(header.e_ident[EI_OSABI]));
// SetArchitecture should have set the vendor to unknown
vendor = spec.GetArchitecture().GetTriple().getVendor();
assert(vendor == llvm::Triple::UnknownVendor);
UNUSED_IF_ASSERT_DISABLED(vendor);
//
// Validate it is ok to remove GetOsFromOSABI
GetOsFromOSABI(header.e_ident[EI_OSABI], ostype);
assert(spec_ostype == ostype);
if (spec_ostype != llvm::Triple::OSType::UnknownOS) {
LLDB_LOGF(log,
"ObjectFileELF::%s file '%s' set ELF module OS type "
"from ELF header OSABI.",
__FUNCTION__, file.GetPath().c_str());
}
if (data_sp->GetByteSize() < length)
data_sp = MapFileData(file, -1, file_offset);
if (data_sp)
data.SetData(data_sp);
// In case there is header extension in the section #0, the header we
// parsed above could have sentinel values for e_phnum, e_shnum, and
// e_shstrndx. In this case we need to reparse the header with a
// bigger data source to get the actual values.
if (header.HasHeaderExtension()) {
lldb::offset_t header_offset = data_offset;
header.Parse(data, &header_offset);
}
uint32_t gnu_debuglink_crc = 0;
std::string gnu_debuglink_file;
SectionHeaderColl section_headers;
lldb_private::UUID &uuid = spec.GetUUID();
GetSectionHeaderInfo(section_headers, data, header, uuid,
gnu_debuglink_file, gnu_debuglink_crc,
spec.GetArchitecture());
llvm::Triple &spec_triple = spec.GetArchitecture().GetTriple();
LLDB_LOGF(log,
"ObjectFileELF::%s file '%s' module set to triple: %s "
"(architecture %s)",
__FUNCTION__, file.GetPath().c_str(),
spec_triple.getTriple().c_str(),
spec.GetArchitecture().GetArchitectureName());
if (!uuid.IsValid()) {
uint32_t core_notes_crc = 0;
if (!gnu_debuglink_crc) {
LLDB_SCOPED_TIMERF(
"Calculating module crc32 %s with size %" PRIu64 " KiB",
file.GetLastPathComponent().AsCString(),
(length - file_offset) / 1024);
// For core files - which usually don't happen to have a
// gnu_debuglink, and are pretty bulky - calculating whole
// contents crc32 would be too much of luxury. Thus we will need
// to fallback to something simpler.
if (header.e_type == llvm::ELF::ET_CORE) {
ProgramHeaderColl program_headers;
GetProgramHeaderInfo(program_headers, data, header);
core_notes_crc =
CalculateELFNotesSegmentsCRC32(program_headers, data);
} else {
gnu_debuglink_crc = calc_crc32(0, data);
}
}
using u32le = llvm::support::ulittle32_t;
if (gnu_debuglink_crc) {
// Use 4 bytes of crc from the .gnu_debuglink section.
u32le data(gnu_debuglink_crc);
uuid = UUID::fromData(&data, sizeof(data));
} else if (core_notes_crc) {
// Use 8 bytes - first 4 bytes for *magic* prefix, mainly to make
// it look different form .gnu_debuglink crc followed by 4 bytes
// of note segments crc.
u32le data[] = {u32le(g_core_uuid_magic), u32le(core_notes_crc)};
uuid = UUID::fromData(data, sizeof(data));
}
}
specs.Append(spec);
}
}
}
}
return specs.GetSize() - initial_count;
}
// PluginInterface protocol
lldb_private::ConstString ObjectFileELF::GetPluginName() {
return GetPluginNameStatic();
}
uint32_t ObjectFileELF::GetPluginVersion() { return m_plugin_version; }
// ObjectFile protocol
ObjectFileELF::ObjectFileELF(const lldb::ModuleSP &module_sp,
DataBufferSP &data_sp, lldb::offset_t data_offset,
const FileSpec *file, lldb::offset_t file_offset,
lldb::offset_t length)
: ObjectFile(module_sp, file, file_offset, length, data_sp, data_offset) {
if (file)
m_file = *file;
}
ObjectFileELF::ObjectFileELF(const lldb::ModuleSP &module_sp,
DataBufferSP &header_data_sp,
const lldb::ProcessSP &process_sp,
addr_t header_addr)
: ObjectFile(module_sp, process_sp, header_addr, header_data_sp) {}
bool ObjectFileELF::IsExecutable() const {
return ((m_header.e_type & ET_EXEC) != 0) || (m_header.e_entry != 0);
}
bool ObjectFileELF::SetLoadAddress(Target &target, lldb::addr_t value,
bool value_is_offset) {
ModuleSP module_sp = GetModule();
if (module_sp) {
size_t num_loaded_sections = 0;
SectionList *section_list = GetSectionList();
if (section_list) {
if (!value_is_offset) {
addr_t base = GetBaseAddress().GetFileAddress();
if (base == LLDB_INVALID_ADDRESS)
return false;
value -= base;
}
const size_t num_sections = section_list->GetSize();
size_t sect_idx = 0;
for (sect_idx = 0; sect_idx < num_sections; ++sect_idx) {
// Iterate through the object file sections to find all of the sections
// that have SHF_ALLOC in their flag bits.
SectionSP section_sp(section_list->GetSectionAtIndex(sect_idx));
if (section_sp->Test(SHF_ALLOC) ||
section_sp->GetType() == eSectionTypeContainer) {
lldb::addr_t load_addr = section_sp->GetFileAddress();
// We don't want to update the load address of a section with type
// eSectionTypeAbsoluteAddress as they already have the absolute load
// address already specified
if (section_sp->GetType() != eSectionTypeAbsoluteAddress)
load_addr += value;
// On 32-bit systems the load address have to fit into 4 bytes. The
// rest of the bytes are the overflow from the addition.
if (GetAddressByteSize() == 4)
load_addr &= 0xFFFFFFFF;
if (target.GetSectionLoadList().SetSectionLoadAddress(section_sp,
load_addr))
++num_loaded_sections;
}
}
return num_loaded_sections > 0;
}
}
return false;
}
ByteOrder ObjectFileELF::GetByteOrder() const {
if (m_header.e_ident[EI_DATA] == ELFDATA2MSB)
return eByteOrderBig;
if (m_header.e_ident[EI_DATA] == ELFDATA2LSB)
return eByteOrderLittle;
return eByteOrderInvalid;
}
uint32_t ObjectFileELF::GetAddressByteSize() const {
return m_data.GetAddressByteSize();
}
AddressClass ObjectFileELF::GetAddressClass(addr_t file_addr) {
Symtab *symtab = GetSymtab();
if (!symtab)
return AddressClass::eUnknown;
// The address class is determined based on the symtab. Ask it from the
// object file what contains the symtab information.
ObjectFile *symtab_objfile = symtab->GetObjectFile();
if (symtab_objfile != nullptr && symtab_objfile != this)
return symtab_objfile->GetAddressClass(file_addr);
auto res = ObjectFile::GetAddressClass(file_addr);
if (res != AddressClass::eCode)
return res;
auto ub = m_address_class_map.upper_bound(file_addr);
if (ub == m_address_class_map.begin()) {
// No entry in the address class map before the address. Return default
// address class for an address in a code section.
return AddressClass::eCode;
}
// Move iterator to the address class entry preceding address
--ub;
return ub->second;
}
size_t ObjectFileELF::SectionIndex(const SectionHeaderCollIter &I) {
return std::distance(m_section_headers.begin(), I);
}
size_t ObjectFileELF::SectionIndex(const SectionHeaderCollConstIter &I) const {
return std::distance(m_section_headers.begin(), I);
}
bool ObjectFileELF::ParseHeader() {
lldb::offset_t offset = 0;
return m_header.Parse(m_data, &offset);
}
UUID ObjectFileELF::GetUUID() {
// Need to parse the section list to get the UUIDs, so make sure that's been
// done.
if (!ParseSectionHeaders() && GetType() != ObjectFile::eTypeCoreFile)
return UUID();
if (!m_uuid) {
using u32le = llvm::support::ulittle32_t;
if (GetType() == ObjectFile::eTypeCoreFile) {
uint32_t core_notes_crc = 0;
if (!ParseProgramHeaders())
return UUID();
core_notes_crc =
CalculateELFNotesSegmentsCRC32(m_program_headers, m_data);
if (core_notes_crc) {
// Use 8 bytes - first 4 bytes for *magic* prefix, mainly to make it
// look different form .gnu_debuglink crc - followed by 4 bytes of note
// segments crc.
u32le data[] = {u32le(g_core_uuid_magic), u32le(core_notes_crc)};
m_uuid = UUID::fromData(data, sizeof(data));
}
} else {
if (!m_gnu_debuglink_crc)
m_gnu_debuglink_crc = calc_crc32(0, m_data);
if (m_gnu_debuglink_crc) {
// Use 4 bytes of crc from the .gnu_debuglink section.
u32le data(m_gnu_debuglink_crc);
m_uuid = UUID::fromData(&data, sizeof(data));
}
}
}
return m_uuid;
}
llvm::Optional<FileSpec> ObjectFileELF::GetDebugLink() {
if (m_gnu_debuglink_file.empty())
return llvm::None;
return FileSpec(m_gnu_debuglink_file);
}
uint32_t ObjectFileELF::GetDependentModules(FileSpecList &files) {
size_t num_modules = ParseDependentModules();
uint32_t num_specs = 0;
for (unsigned i = 0; i < num_modules; ++i) {
if (files.AppendIfUnique(m_filespec_up->GetFileSpecAtIndex(i)))
num_specs++;
}
return num_specs;
}
Address ObjectFileELF::GetImageInfoAddress(Target *target) {
if (!ParseDynamicSymbols())
return Address();
SectionList *section_list = GetSectionList();
if (!section_list)
return Address();
// Find the SHT_DYNAMIC (.dynamic) section.
SectionSP dynsym_section_sp(
section_list->FindSectionByType(eSectionTypeELFDynamicLinkInfo, true));
if (!dynsym_section_sp)
return Address();
assert(dynsym_section_sp->GetObjectFile() == this);
user_id_t dynsym_id = dynsym_section_sp->GetID();
const ELFSectionHeaderInfo *dynsym_hdr = GetSectionHeaderByIndex(dynsym_id);
if (!dynsym_hdr)
return Address();
for (size_t i = 0; i < m_dynamic_symbols.size(); ++i) {
ELFDynamic &symbol = m_dynamic_symbols[i];
if (symbol.d_tag == DT_DEBUG) {
// Compute the offset as the number of previous entries plus the size of
// d_tag.
addr_t offset = i * dynsym_hdr->sh_entsize + GetAddressByteSize();
return Address(dynsym_section_sp, offset);
}
// MIPS executables uses DT_MIPS_RLD_MAP_REL to support PIE. DT_MIPS_RLD_MAP
// exists in non-PIE.
else if ((symbol.d_tag == DT_MIPS_RLD_MAP ||
symbol.d_tag == DT_MIPS_RLD_MAP_REL) &&
target) {
addr_t offset = i * dynsym_hdr->sh_entsize + GetAddressByteSize();
addr_t dyn_base = dynsym_section_sp->GetLoadBaseAddress(target);
if (dyn_base == LLDB_INVALID_ADDRESS)
return Address();
Status error;
if (symbol.d_tag == DT_MIPS_RLD_MAP) {
// DT_MIPS_RLD_MAP tag stores an absolute address of the debug pointer.
Address addr;
if (target->ReadPointerFromMemory(dyn_base + offset, error, addr, true))
return addr;
}
if (symbol.d_tag == DT_MIPS_RLD_MAP_REL) {
// DT_MIPS_RLD_MAP_REL tag stores the offset to the debug pointer,
// relative to the address of the tag.
uint64_t rel_offset;
rel_offset = target->ReadUnsignedIntegerFromMemory(
dyn_base + offset, GetAddressByteSize(), UINT64_MAX, error, true);
if (error.Success() && rel_offset != UINT64_MAX) {
Address addr;
addr_t debug_ptr_address =
dyn_base + (offset - GetAddressByteSize()) + rel_offset;
addr.SetOffset(debug_ptr_address);
return addr;
}
}
}
}
return Address();
}
lldb_private::Address ObjectFileELF::GetEntryPointAddress() {
if (m_entry_point_address.IsValid())
return m_entry_point_address;
if (!ParseHeader() || !IsExecutable())
return m_entry_point_address;
SectionList *section_list = GetSectionList();
addr_t offset = m_header.e_entry;
if (!section_list)
m_entry_point_address.SetOffset(offset);
else
m_entry_point_address.ResolveAddressUsingFileSections(offset, section_list);
return m_entry_point_address;
}
Address ObjectFileELF::GetBaseAddress() {
for (const auto &EnumPHdr : llvm::enumerate(ProgramHeaders())) {
const ELFProgramHeader &H = EnumPHdr.value();
if (H.p_type != PT_LOAD)
continue;
return Address(
GetSectionList()->FindSectionByID(SegmentID(EnumPHdr.index())), 0);
}
return LLDB_INVALID_ADDRESS;
}
// ParseDependentModules
size_t ObjectFileELF::ParseDependentModules() {
if (m_filespec_up)
return m_filespec_up->GetSize();
m_filespec_up = std::make_unique<FileSpecList>();
if (!ParseSectionHeaders())
return 0;
SectionList *section_list = GetSectionList();
if (!section_list)
return 0;
// Find the SHT_DYNAMIC section.
Section *dynsym =
section_list->FindSectionByType(eSectionTypeELFDynamicLinkInfo, true)
.get();
if (!dynsym)
return 0;
assert(dynsym->GetObjectFile() == this);
const ELFSectionHeaderInfo *header = GetSectionHeaderByIndex(dynsym->GetID());
if (!header)
return 0;
// sh_link: section header index of string table used by entries in the
// section.
Section *dynstr = section_list->FindSectionByID(header->sh_link).get();
if (!dynstr)
return 0;
DataExtractor dynsym_data;
DataExtractor dynstr_data;
if (ReadSectionData(dynsym, dynsym_data) &&
ReadSectionData(dynstr, dynstr_data)) {
ELFDynamic symbol;
const lldb::offset_t section_size = dynsym_data.GetByteSize();
lldb::offset_t offset = 0;
// The only type of entries we are concerned with are tagged DT_NEEDED,
// yielding the name of a required library.
while (offset < section_size) {
if (!symbol.Parse(dynsym_data, &offset))
break;
if (symbol.d_tag != DT_NEEDED)
continue;
uint32_t str_index = static_cast<uint32_t>(symbol.d_val);
const char *lib_name = dynstr_data.PeekCStr(str_index);
FileSpec file_spec(lib_name);
FileSystem::Instance().Resolve(file_spec);
m_filespec_up->Append(file_spec);
}
}
return m_filespec_up->GetSize();
}
// GetProgramHeaderInfo
size_t ObjectFileELF::GetProgramHeaderInfo(ProgramHeaderColl &program_headers,
DataExtractor &object_data,
const ELFHeader &header) {
// We have already parsed the program headers
if (!program_headers.empty())
return program_headers.size();
// If there are no program headers to read we are done.
if (header.e_phnum == 0)
return 0;
program_headers.resize(header.e_phnum);
if (program_headers.size() != header.e_phnum)
return 0;
const size_t ph_size = header.e_phnum * header.e_phentsize;
const elf_off ph_offset = header.e_phoff;
DataExtractor data;
if (data.SetData(object_data, ph_offset, ph_size) != ph_size)
return 0;
uint32_t idx;
lldb::offset_t offset;
for (idx = 0, offset = 0; idx < header.e_phnum; ++idx) {
if (!program_headers[idx].Parse(data, &offset))
break;
}