blob: 3490bcf862e8a7f9501acf0ac57e9b2af54749cc [file] [log] [blame]
/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "elf_file.h"
#include <inttypes.h>
#include <sys/types.h>
#include <unistd.h>
#include "arch/instruction_set.h"
#include "base/logging.h"
#include "base/stringprintf.h"
#include "base/stl_util.h"
#include "base/unix_file/fd_file.h"
#include "dwarf.h"
#include "elf_file_impl.h"
#include "elf_utils.h"
#include "leb128.h"
#include "utils.h"
namespace art {
// -------------------------------------------------------------------
// Binary GDB JIT Interface as described in
// http://sourceware.org/gdb/onlinedocs/gdb/Declarations.html
extern "C" {
typedef enum {
JIT_NOACTION = 0,
JIT_REGISTER_FN,
JIT_UNREGISTER_FN
} JITAction;
struct JITCodeEntry {
JITCodeEntry* next_;
JITCodeEntry* prev_;
const uint8_t *symfile_addr_;
uint64_t symfile_size_;
};
struct JITDescriptor {
uint32_t version_;
uint32_t action_flag_;
JITCodeEntry* relevant_entry_;
JITCodeEntry* first_entry_;
};
// GDB will place breakpoint into this function.
// To prevent GCC from inlining or removing it we place noinline attribute
// and inline assembler statement inside.
void __attribute__((noinline)) __jit_debug_register_code();
void __attribute__((noinline)) __jit_debug_register_code() {
__asm__("");
}
// GDB will inspect contents of this descriptor.
// Static initialization is necessary to prevent GDB from seeing
// uninitialized descriptor.
JITDescriptor __jit_debug_descriptor = { 1, JIT_NOACTION, nullptr, nullptr };
}
static JITCodeEntry* CreateCodeEntry(const uint8_t *symfile_addr,
uintptr_t symfile_size) {
JITCodeEntry* entry = new JITCodeEntry;
entry->symfile_addr_ = symfile_addr;
entry->symfile_size_ = symfile_size;
entry->prev_ = nullptr;
// TODO: Do we need a lock here?
entry->next_ = __jit_debug_descriptor.first_entry_;
if (entry->next_ != nullptr) {
entry->next_->prev_ = entry;
}
__jit_debug_descriptor.first_entry_ = entry;
__jit_debug_descriptor.relevant_entry_ = entry;
__jit_debug_descriptor.action_flag_ = JIT_REGISTER_FN;
__jit_debug_register_code();
return entry;
}
static void UnregisterCodeEntry(JITCodeEntry* entry) {
// TODO: Do we need a lock here?
if (entry->prev_ != nullptr) {
entry->prev_->next_ = entry->next_;
} else {
__jit_debug_descriptor.first_entry_ = entry->next_;
}
if (entry->next_ != nullptr) {
entry->next_->prev_ = entry->prev_;
}
__jit_debug_descriptor.relevant_entry_ = entry;
__jit_debug_descriptor.action_flag_ = JIT_UNREGISTER_FN;
__jit_debug_register_code();
delete entry;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::ElfFileImpl(File* file, bool writable, bool program_header_only, uint8_t* requested_base)
: file_(file),
writable_(writable),
program_header_only_(program_header_only),
header_(nullptr),
base_address_(nullptr),
program_headers_start_(nullptr),
section_headers_start_(nullptr),
dynamic_program_header_(nullptr),
dynamic_section_start_(nullptr),
symtab_section_start_(nullptr),
dynsym_section_start_(nullptr),
strtab_section_start_(nullptr),
dynstr_section_start_(nullptr),
hash_section_start_(nullptr),
symtab_symbol_table_(nullptr),
dynsym_symbol_table_(nullptr),
jit_elf_image_(nullptr),
jit_gdb_entry_(nullptr),
requested_base_(requested_base) {
CHECK(file != nullptr);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>*
ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::Open(File* file, bool writable, bool program_header_only,
std::string* error_msg, uint8_t* requested_base) {
std::unique_ptr<ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>>
elf_file(new ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
(file, writable, program_header_only, requested_base));
int prot;
int flags;
if (writable) {
prot = PROT_READ | PROT_WRITE;
flags = MAP_SHARED;
} else {
prot = PROT_READ;
flags = MAP_PRIVATE;
}
if (!elf_file->Setup(prot, flags, error_msg)) {
return nullptr;
}
return elf_file.release();
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>*
ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::Open(File* file, int prot, int flags, std::string* error_msg) {
std::unique_ptr<ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>>
elf_file(new ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
(file, (prot & PROT_WRITE) == PROT_WRITE, /*program_header_only*/false,
/*requested_base*/nullptr));
if (!elf_file->Setup(prot, flags, error_msg)) {
return nullptr;
}
return elf_file.release();
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::Setup(int prot, int flags, std::string* error_msg) {
int64_t temp_file_length = file_->GetLength();
if (temp_file_length < 0) {
errno = -temp_file_length;
*error_msg = StringPrintf("Failed to get length of file: '%s' fd=%d: %s",
file_->GetPath().c_str(), file_->Fd(), strerror(errno));
return false;
}
size_t file_length = static_cast<size_t>(temp_file_length);
if (file_length < sizeof(Elf_Ehdr)) {
*error_msg = StringPrintf("File size of %zd bytes not large enough to contain ELF header of "
"%zd bytes: '%s'", file_length, sizeof(Elf_Ehdr),
file_->GetPath().c_str());
return false;
}
if (program_header_only_) {
// first just map ELF header to get program header size information
size_t elf_header_size = sizeof(Elf_Ehdr);
if (!SetMap(MemMap::MapFile(elf_header_size, prot, flags, file_->Fd(), 0,
file_->GetPath().c_str(), error_msg),
error_msg)) {
return false;
}
// then remap to cover program header
size_t program_header_size = header_->e_phoff + (header_->e_phentsize * header_->e_phnum);
if (file_length < program_header_size) {
*error_msg = StringPrintf("File size of %zd bytes not large enough to contain ELF program "
"header of %zd bytes: '%s'", file_length,
sizeof(Elf_Ehdr), file_->GetPath().c_str());
return false;
}
if (!SetMap(MemMap::MapFile(program_header_size, prot, flags, file_->Fd(), 0,
file_->GetPath().c_str(), error_msg),
error_msg)) {
*error_msg = StringPrintf("Failed to map ELF program headers: %s", error_msg->c_str());
return false;
}
} else {
// otherwise map entire file
if (!SetMap(MemMap::MapFile(file_->GetLength(), prot, flags, file_->Fd(), 0,
file_->GetPath().c_str(), error_msg),
error_msg)) {
*error_msg = StringPrintf("Failed to map ELF file: %s", error_msg->c_str());
return false;
}
}
if (program_header_only_) {
program_headers_start_ = Begin() + GetHeader().e_phoff;
} else {
if (!CheckAndSet(GetHeader().e_phoff, "program headers", &program_headers_start_, error_msg)) {
return false;
}
// Setup section headers.
if (!CheckAndSet(GetHeader().e_shoff, "section headers", &section_headers_start_, error_msg)) {
return false;
}
// Find shstrtab.
Elf_Shdr* shstrtab_section_header = GetSectionNameStringSection();
if (shstrtab_section_header == nullptr) {
*error_msg = StringPrintf("Failed to find shstrtab section header in ELF file: '%s'",
file_->GetPath().c_str());
return false;
}
// Find .dynamic section info from program header
dynamic_program_header_ = FindProgamHeaderByType(PT_DYNAMIC);
if (dynamic_program_header_ == nullptr) {
*error_msg = StringPrintf("Failed to find PT_DYNAMIC program header in ELF file: '%s'",
file_->GetPath().c_str());
return false;
}
if (!CheckAndSet(GetDynamicProgramHeader().p_offset, "dynamic section",
reinterpret_cast<uint8_t**>(&dynamic_section_start_), error_msg)) {
return false;
}
// Find other sections from section headers
for (Elf_Word i = 0; i < GetSectionHeaderNum(); i++) {
Elf_Shdr* section_header = GetSectionHeader(i);
if (section_header == nullptr) {
*error_msg = StringPrintf("Failed to find section header for section %d in ELF file: '%s'",
i, file_->GetPath().c_str());
return false;
}
switch (section_header->sh_type) {
case SHT_SYMTAB: {
if (!CheckAndSet(section_header->sh_offset, "symtab",
reinterpret_cast<uint8_t**>(&symtab_section_start_), error_msg)) {
return false;
}
break;
}
case SHT_DYNSYM: {
if (!CheckAndSet(section_header->sh_offset, "dynsym",
reinterpret_cast<uint8_t**>(&dynsym_section_start_), error_msg)) {
return false;
}
break;
}
case SHT_STRTAB: {
// TODO: base these off of sh_link from .symtab and .dynsym above
if ((section_header->sh_flags & SHF_ALLOC) != 0) {
// Check that this is named ".dynstr" and ignore otherwise.
const char* header_name = GetString(*shstrtab_section_header, section_header->sh_name);
if (strncmp(".dynstr", header_name, 8) == 0) {
if (!CheckAndSet(section_header->sh_offset, "dynstr",
reinterpret_cast<uint8_t**>(&dynstr_section_start_), error_msg)) {
return false;
}
}
} else {
// Check that this is named ".strtab" and ignore otherwise.
const char* header_name = GetString(*shstrtab_section_header, section_header->sh_name);
if (strncmp(".strtab", header_name, 8) == 0) {
if (!CheckAndSet(section_header->sh_offset, "strtab",
reinterpret_cast<uint8_t**>(&strtab_section_start_), error_msg)) {
return false;
}
}
}
break;
}
case SHT_DYNAMIC: {
if (reinterpret_cast<uint8_t*>(dynamic_section_start_) !=
Begin() + section_header->sh_offset) {
LOG(WARNING) << "Failed to find matching SHT_DYNAMIC for PT_DYNAMIC in "
<< file_->GetPath() << ": " << std::hex
<< reinterpret_cast<void*>(dynamic_section_start_)
<< " != " << reinterpret_cast<void*>(Begin() + section_header->sh_offset);
return false;
}
break;
}
case SHT_HASH: {
if (!CheckAndSet(section_header->sh_offset, "hash section",
reinterpret_cast<uint8_t**>(&hash_section_start_), error_msg)) {
return false;
}
break;
}
}
}
// Check for the existence of some sections.
if (!CheckSectionsExist(error_msg)) {
return false;
}
}
return true;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::~ElfFileImpl() {
STLDeleteElements(&segments_);
delete symtab_symbol_table_;
delete dynsym_symbol_table_;
delete jit_elf_image_;
if (jit_gdb_entry_) {
UnregisterCodeEntry(jit_gdb_entry_);
}
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::CheckAndSet(Elf32_Off offset, const char* label,
uint8_t** target, std::string* error_msg) {
if (Begin() + offset >= End()) {
*error_msg = StringPrintf("Offset %d is out of range for %s in ELF file: '%s'", offset, label,
file_->GetPath().c_str());
return false;
}
*target = Begin() + offset;
return true;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::CheckSectionsLinked(const uint8_t* source, const uint8_t* target) const {
// Only works in whole-program mode, as we need to iterate over the sections.
// Note that we normally can't search by type, as duplicates are allowed for most section types.
if (program_header_only_) {
return true;
}
Elf_Shdr* source_section = nullptr;
Elf_Word target_index = 0;
bool target_found = false;
for (Elf_Word i = 0; i < GetSectionHeaderNum(); i++) {
Elf_Shdr* section_header = GetSectionHeader(i);
if (Begin() + section_header->sh_offset == source) {
// Found the source.
source_section = section_header;
if (target_index) {
break;
}
} else if (Begin() + section_header->sh_offset == target) {
target_index = i;
target_found = true;
if (source_section != nullptr) {
break;
}
}
}
return target_found && source_section != nullptr && source_section->sh_link == target_index;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::CheckSectionsExist(std::string* error_msg) const {
if (!program_header_only_) {
// If in full mode, need section headers.
if (section_headers_start_ == nullptr) {
*error_msg = StringPrintf("No section headers in ELF file: '%s'", file_->GetPath().c_str());
return false;
}
}
// This is redundant, but defensive.
if (dynamic_program_header_ == nullptr) {
*error_msg = StringPrintf("Failed to find PT_DYNAMIC program header in ELF file: '%s'",
file_->GetPath().c_str());
return false;
}
// Need a dynamic section. This is redundant, but defensive.
if (dynamic_section_start_ == nullptr) {
*error_msg = StringPrintf("Failed to find dynamic section in ELF file: '%s'",
file_->GetPath().c_str());
return false;
}
// Symtab validation. These is not really a hard failure, as we are currently not using the
// symtab internally, but it's nice to be defensive.
if (symtab_section_start_ != nullptr) {
// When there's a symtab, there should be a strtab.
if (strtab_section_start_ == nullptr) {
*error_msg = StringPrintf("No strtab for symtab in ELF file: '%s'", file_->GetPath().c_str());
return false;
}
// The symtab should link to the strtab.
if (!CheckSectionsLinked(reinterpret_cast<const uint8_t*>(symtab_section_start_),
reinterpret_cast<const uint8_t*>(strtab_section_start_))) {
*error_msg = StringPrintf("Symtab is not linked to the strtab in ELF file: '%s'",
file_->GetPath().c_str());
return false;
}
}
// We always need a dynstr & dynsym.
if (dynstr_section_start_ == nullptr) {
*error_msg = StringPrintf("No dynstr in ELF file: '%s'", file_->GetPath().c_str());
return false;
}
if (dynsym_section_start_ == nullptr) {
*error_msg = StringPrintf("No dynsym in ELF file: '%s'", file_->GetPath().c_str());
return false;
}
// Need a hash section for dynamic symbol lookup.
if (hash_section_start_ == nullptr) {
*error_msg = StringPrintf("Failed to find hash section in ELF file: '%s'",
file_->GetPath().c_str());
return false;
}
// And the hash section should be linking to the dynsym.
if (!CheckSectionsLinked(reinterpret_cast<const uint8_t*>(hash_section_start_),
reinterpret_cast<const uint8_t*>(dynsym_section_start_))) {
*error_msg = StringPrintf("Hash section is not linked to the dynstr in ELF file: '%s'",
file_->GetPath().c_str());
return false;
}
// We'd also like to confirm a shstrtab in program_header_only_ mode (else Open() does this for
// us). This is usually the last in an oat file, and a good indicator of whether writing was
// successful (or the process crashed and left garbage).
if (program_header_only_) {
// It might not be mapped, but we can compare against the file size.
int64_t offset = static_cast<int64_t>(GetHeader().e_shoff +
(GetHeader().e_shstrndx * GetHeader().e_shentsize));
if (offset >= file_->GetLength()) {
*error_msg = StringPrintf("Shstrtab is not in the mapped ELF file: '%s'",
file_->GetPath().c_str());
return false;
}
}
return true;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::SetMap(MemMap* map, std::string* error_msg) {
if (map == nullptr) {
// MemMap::Open should have already set an error.
DCHECK(!error_msg->empty());
return false;
}
map_.reset(map);
CHECK(map_.get() != nullptr) << file_->GetPath();
CHECK(map_->Begin() != nullptr) << file_->GetPath();
header_ = reinterpret_cast<Elf_Ehdr*>(map_->Begin());
if ((ELFMAG0 != header_->e_ident[EI_MAG0])
|| (ELFMAG1 != header_->e_ident[EI_MAG1])
|| (ELFMAG2 != header_->e_ident[EI_MAG2])
|| (ELFMAG3 != header_->e_ident[EI_MAG3])) {
*error_msg = StringPrintf("Failed to find ELF magic value %d %d %d %d in %s, found %d %d %d %d",
ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3,
file_->GetPath().c_str(),
header_->e_ident[EI_MAG0],
header_->e_ident[EI_MAG1],
header_->e_ident[EI_MAG2],
header_->e_ident[EI_MAG3]);
return false;
}
uint8_t elf_class = (sizeof(Elf_Addr) == sizeof(Elf64_Addr)) ? ELFCLASS64 : ELFCLASS32;
if (elf_class != header_->e_ident[EI_CLASS]) {
*error_msg = StringPrintf("Failed to find expected EI_CLASS value %d in %s, found %d",
elf_class,
file_->GetPath().c_str(),
header_->e_ident[EI_CLASS]);
return false;
}
if (ELFDATA2LSB != header_->e_ident[EI_DATA]) {
*error_msg = StringPrintf("Failed to find expected EI_DATA value %d in %s, found %d",
ELFDATA2LSB,
file_->GetPath().c_str(),
header_->e_ident[EI_CLASS]);
return false;
}
if (EV_CURRENT != header_->e_ident[EI_VERSION]) {
*error_msg = StringPrintf("Failed to find expected EI_VERSION value %d in %s, found %d",
EV_CURRENT,
file_->GetPath().c_str(),
header_->e_ident[EI_CLASS]);
return false;
}
if (ET_DYN != header_->e_type) {
*error_msg = StringPrintf("Failed to find expected e_type value %d in %s, found %d",
ET_DYN,
file_->GetPath().c_str(),
header_->e_type);
return false;
}
if (EV_CURRENT != header_->e_version) {
*error_msg = StringPrintf("Failed to find expected e_version value %d in %s, found %d",
EV_CURRENT,
file_->GetPath().c_str(),
header_->e_version);
return false;
}
if (0 != header_->e_entry) {
*error_msg = StringPrintf("Failed to find expected e_entry value %d in %s, found %d",
0,
file_->GetPath().c_str(),
static_cast<int32_t>(header_->e_entry));
return false;
}
if (0 == header_->e_phoff) {
*error_msg = StringPrintf("Failed to find non-zero e_phoff value in %s",
file_->GetPath().c_str());
return false;
}
if (0 == header_->e_shoff) {
*error_msg = StringPrintf("Failed to find non-zero e_shoff value in %s",
file_->GetPath().c_str());
return false;
}
if (0 == header_->e_ehsize) {
*error_msg = StringPrintf("Failed to find non-zero e_ehsize value in %s",
file_->GetPath().c_str());
return false;
}
if (0 == header_->e_phentsize) {
*error_msg = StringPrintf("Failed to find non-zero e_phentsize value in %s",
file_->GetPath().c_str());
return false;
}
if (0 == header_->e_phnum) {
*error_msg = StringPrintf("Failed to find non-zero e_phnum value in %s",
file_->GetPath().c_str());
return false;
}
if (0 == header_->e_shentsize) {
*error_msg = StringPrintf("Failed to find non-zero e_shentsize value in %s",
file_->GetPath().c_str());
return false;
}
if (0 == header_->e_shnum) {
*error_msg = StringPrintf("Failed to find non-zero e_shnum value in %s",
file_->GetPath().c_str());
return false;
}
if (0 == header_->e_shstrndx) {
*error_msg = StringPrintf("Failed to find non-zero e_shstrndx value in %s",
file_->GetPath().c_str());
return false;
}
if (header_->e_shstrndx >= header_->e_shnum) {
*error_msg = StringPrintf("Failed to find e_shnum value %d less than %d in %s",
header_->e_shstrndx,
header_->e_shnum,
file_->GetPath().c_str());
return false;
}
if (!program_header_only_) {
if (header_->e_phoff >= Size()) {
*error_msg = StringPrintf("Failed to find e_phoff value %" PRIu64 " less than %zd in %s",
static_cast<uint64_t>(header_->e_phoff),
Size(),
file_->GetPath().c_str());
return false;
}
if (header_->e_shoff >= Size()) {
*error_msg = StringPrintf("Failed to find e_shoff value %" PRIu64 " less than %zd in %s",
static_cast<uint64_t>(header_->e_shoff),
Size(),
file_->GetPath().c_str());
return false;
}
}
return true;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Ehdr& ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetHeader() const {
CHECK(header_ != nullptr); // Header has been checked in SetMap. This is a sanity check.
return *header_;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
uint8_t* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetProgramHeadersStart() const {
CHECK(program_headers_start_ != nullptr); // Header has been set in Setup. This is a sanity
// check.
return program_headers_start_;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
uint8_t* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetSectionHeadersStart() const {
CHECK(!program_header_only_); // Only used in "full" mode.
CHECK(section_headers_start_ != nullptr); // Is checked in CheckSectionsExist. Sanity check.
return section_headers_start_;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Phdr& ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetDynamicProgramHeader() const {
CHECK(dynamic_program_header_ != nullptr); // Is checked in CheckSectionsExist. Sanity check.
return *dynamic_program_header_;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Dyn* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetDynamicSectionStart() const {
CHECK(dynamic_section_start_ != nullptr); // Is checked in CheckSectionsExist. Sanity check.
return dynamic_section_start_;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Sym* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetSymbolSectionStart(Elf_Word section_type) const {
CHECK(IsSymbolSectionType(section_type)) << file_->GetPath() << " " << section_type;
switch (section_type) {
case SHT_SYMTAB: {
return symtab_section_start_;
break;
}
case SHT_DYNSYM: {
return dynsym_section_start_;
break;
}
default: {
LOG(FATAL) << section_type;
return nullptr;
}
}
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
const char* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetStringSectionStart(Elf_Word section_type) const {
CHECK(IsSymbolSectionType(section_type)) << file_->GetPath() << " " << section_type;
switch (section_type) {
case SHT_SYMTAB: {
return strtab_section_start_;
}
case SHT_DYNSYM: {
return dynstr_section_start_;
}
default: {
LOG(FATAL) << section_type;
return nullptr;
}
}
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
const char* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetString(Elf_Word section_type, Elf_Word i) const {
CHECK(IsSymbolSectionType(section_type)) << file_->GetPath() << " " << section_type;
if (i == 0) {
return nullptr;
}
const char* string_section_start = GetStringSectionStart(section_type);
if (string_section_start == nullptr) {
return nullptr;
}
return string_section_start + i;
}
// WARNING: The following methods do not check for an error condition (non-existent hash section).
// It is the caller's job to do this.
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetHashSectionStart() const {
return hash_section_start_;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetHashBucketNum() const {
return GetHashSectionStart()[0];
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetHashChainNum() const {
return GetHashSectionStart()[1];
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetHashBucket(size_t i, bool* ok) const {
if (i >= GetHashBucketNum()) {
*ok = false;
return 0;
}
*ok = true;
// 0 is nbucket, 1 is nchain
return GetHashSectionStart()[2 + i];
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetHashChain(size_t i, bool* ok) const {
if (i >= GetHashChainNum()) {
*ok = false;
return 0;
}
*ok = true;
// 0 is nbucket, 1 is nchain, & chains are after buckets
return GetHashSectionStart()[2 + GetHashBucketNum() + i];
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetProgramHeaderNum() const {
return GetHeader().e_phnum;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Phdr* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetProgramHeader(Elf_Word i) const {
CHECK_LT(i, GetProgramHeaderNum()) << file_->GetPath(); // Sanity check for caller.
uint8_t* program_header = GetProgramHeadersStart() + (i * GetHeader().e_phentsize);
if (program_header >= End()) {
return nullptr; // Failure condition.
}
return reinterpret_cast<Elf_Phdr*>(program_header);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Phdr* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FindProgamHeaderByType(Elf_Word type) const {
for (Elf_Word i = 0; i < GetProgramHeaderNum(); i++) {
Elf_Phdr* program_header = GetProgramHeader(i);
if (program_header->p_type == type) {
return program_header;
}
}
return nullptr;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetSectionHeaderNum() const {
return GetHeader().e_shnum;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Shdr* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetSectionHeader(Elf_Word i) const {
// Can only access arbitrary sections when we have the whole file, not just program header.
// Even if we Load(), it doesn't bring in all the sections.
CHECK(!program_header_only_) << file_->GetPath();
if (i >= GetSectionHeaderNum()) {
return nullptr; // Failure condition.
}
uint8_t* section_header = GetSectionHeadersStart() + (i * GetHeader().e_shentsize);
if (section_header >= End()) {
return nullptr; // Failure condition.
}
return reinterpret_cast<Elf_Shdr*>(section_header);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Shdr* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FindSectionByType(Elf_Word type) const {
// Can only access arbitrary sections when we have the whole file, not just program header.
// We could change this to switch on known types if they were detected during loading.
CHECK(!program_header_only_) << file_->GetPath();
for (Elf_Word i = 0; i < GetSectionHeaderNum(); i++) {
Elf_Shdr* section_header = GetSectionHeader(i);
if (section_header->sh_type == type) {
return section_header;
}
}
return nullptr;
}
// from bionic
static unsigned elfhash(const char *_name) {
const unsigned char *name = (const unsigned char *) _name;
unsigned h = 0, g;
while (*name) {
h = (h << 4) + *name++;
g = h & 0xf0000000;
h ^= g;
h ^= g >> 24;
}
return h;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Shdr* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetSectionNameStringSection() const {
return GetSectionHeader(GetHeader().e_shstrndx);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
const uint8_t* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FindDynamicSymbolAddress(const std::string& symbol_name) const {
// Check that we have a hash section.
if (GetHashSectionStart() == nullptr) {
return nullptr; // Failure condition.
}
const Elf_Sym* sym = FindDynamicSymbol(symbol_name);
if (sym != nullptr) {
// TODO: we need to change this to calculate base_address_ in ::Open,
// otherwise it will be wrongly 0 if ::Load has not yet been called.
return base_address_ + sym->st_value;
} else {
return nullptr;
}
}
// WARNING: Only called from FindDynamicSymbolAddress. Elides check for hash section.
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
const Elf_Sym* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FindDynamicSymbol(const std::string& symbol_name) const {
if (GetHashBucketNum() == 0) {
// No dynamic symbols at all.
return nullptr;
}
Elf_Word hash = elfhash(symbol_name.c_str());
Elf_Word bucket_index = hash % GetHashBucketNum();
bool ok;
Elf_Word symbol_and_chain_index = GetHashBucket(bucket_index, &ok);
if (!ok) {
return nullptr;
}
while (symbol_and_chain_index != 0 /* STN_UNDEF */) {
Elf_Sym* symbol = GetSymbol(SHT_DYNSYM, symbol_and_chain_index);
if (symbol == nullptr) {
return nullptr; // Failure condition.
}
const char* name = GetString(SHT_DYNSYM, symbol->st_name);
if (symbol_name == name) {
return symbol;
}
symbol_and_chain_index = GetHashChain(symbol_and_chain_index, &ok);
if (!ok) {
return nullptr;
}
}
return nullptr;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::IsSymbolSectionType(Elf_Word section_type) {
return ((section_type == SHT_SYMTAB) || (section_type == SHT_DYNSYM));
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetSymbolNum(Elf_Shdr& section_header) const {
CHECK(IsSymbolSectionType(section_header.sh_type))
<< file_->GetPath() << " " << section_header.sh_type;
CHECK_NE(0U, section_header.sh_entsize) << file_->GetPath();
return section_header.sh_size / section_header.sh_entsize;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Sym* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetSymbol(Elf_Word section_type,
Elf_Word i) const {
Elf_Sym* sym_start = GetSymbolSectionStart(section_type);
if (sym_start == nullptr) {
return nullptr;
}
return sym_start + i;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
typename ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::SymbolTable** ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetSymbolTable(Elf_Word section_type) {
CHECK(IsSymbolSectionType(section_type)) << file_->GetPath() << " " << section_type;
switch (section_type) {
case SHT_SYMTAB: {
return &symtab_symbol_table_;
}
case SHT_DYNSYM: {
return &dynsym_symbol_table_;
}
default: {
LOG(FATAL) << section_type;
return nullptr;
}
}
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Sym* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FindSymbolByName(Elf_Word section_type,
const std::string& symbol_name,
bool build_map) {
CHECK(!program_header_only_) << file_->GetPath();
CHECK(IsSymbolSectionType(section_type)) << file_->GetPath() << " " << section_type;
SymbolTable** symbol_table = GetSymbolTable(section_type);
if (*symbol_table != nullptr || build_map) {
if (*symbol_table == nullptr) {
DCHECK(build_map);
*symbol_table = new SymbolTable;
Elf_Shdr* symbol_section = FindSectionByType(section_type);
if (symbol_section == nullptr) {
return nullptr; // Failure condition.
}
Elf_Shdr* string_section = GetSectionHeader(symbol_section->sh_link);
if (string_section == nullptr) {
return nullptr; // Failure condition.
}
for (uint32_t i = 0; i < GetSymbolNum(*symbol_section); i++) {
Elf_Sym* symbol = GetSymbol(section_type, i);
if (symbol == nullptr) {
return nullptr; // Failure condition.
}
unsigned char type = (sizeof(Elf_Addr) == sizeof(Elf64_Addr))
? ELF64_ST_TYPE(symbol->st_info)
: ELF32_ST_TYPE(symbol->st_info);
if (type == STT_NOTYPE) {
continue;
}
const char* name = GetString(*string_section, symbol->st_name);
if (name == nullptr) {
continue;
}
std::pair<typename SymbolTable::iterator, bool> result =
(*symbol_table)->insert(std::make_pair(name, symbol));
if (!result.second) {
// If a duplicate, make sure it has the same logical value. Seen on x86.
if ((symbol->st_value != result.first->second->st_value) ||
(symbol->st_size != result.first->second->st_size) ||
(symbol->st_info != result.first->second->st_info) ||
(symbol->st_other != result.first->second->st_other) ||
(symbol->st_shndx != result.first->second->st_shndx)) {
return nullptr; // Failure condition.
}
}
}
}
CHECK(*symbol_table != nullptr);
typename SymbolTable::const_iterator it = (*symbol_table)->find(symbol_name);
if (it == (*symbol_table)->end()) {
return nullptr;
}
return it->second;
}
// Fall back to linear search
Elf_Shdr* symbol_section = FindSectionByType(section_type);
if (symbol_section == nullptr) {
return nullptr;
}
Elf_Shdr* string_section = GetSectionHeader(symbol_section->sh_link);
if (string_section == nullptr) {
return nullptr;
}
for (uint32_t i = 0; i < GetSymbolNum(*symbol_section); i++) {
Elf_Sym* symbol = GetSymbol(section_type, i);
if (symbol == nullptr) {
return nullptr; // Failure condition.
}
const char* name = GetString(*string_section, symbol->st_name);
if (name == nullptr) {
continue;
}
if (symbol_name == name) {
return symbol;
}
}
return nullptr;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Addr ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FindSymbolAddress(Elf_Word section_type,
const std::string& symbol_name,
bool build_map) {
Elf_Sym* symbol = FindSymbolByName(section_type, symbol_name, build_map);
if (symbol == nullptr) {
return 0;
}
return symbol->st_value;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
const char* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetString(Elf_Shdr& string_section, Elf_Word i) const {
CHECK(!program_header_only_) << file_->GetPath();
// TODO: remove this static_cast from enum when using -std=gnu++0x
if (static_cast<Elf_Word>(SHT_STRTAB) != string_section.sh_type) {
return nullptr; // Failure condition.
}
if (i >= string_section.sh_size) {
return nullptr;
}
if (i == 0) {
return nullptr;
}
uint8_t* strings = Begin() + string_section.sh_offset;
uint8_t* string = strings + i;
if (string >= End()) {
return nullptr;
}
return reinterpret_cast<const char*>(string);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetDynamicNum() const {
return GetDynamicProgramHeader().p_filesz / sizeof(Elf_Dyn);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Dyn& ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetDynamic(Elf_Word i) const {
CHECK_LT(i, GetDynamicNum()) << file_->GetPath();
return *(GetDynamicSectionStart() + i);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Dyn* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FindDynamicByType(Elf_Sword type) const {
for (Elf_Word i = 0; i < GetDynamicNum(); i++) {
Elf_Dyn* dyn = &GetDynamic(i);
if (dyn->d_tag == type) {
return dyn;
}
}
return NULL;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FindDynamicValueByType(Elf_Sword type) const {
Elf_Dyn* dyn = FindDynamicByType(type);
if (dyn == NULL) {
return 0;
} else {
return dyn->d_un.d_val;
}
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Rel* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetRelSectionStart(Elf_Shdr& section_header) const {
CHECK(SHT_REL == section_header.sh_type) << file_->GetPath() << " " << section_header.sh_type;
return reinterpret_cast<Elf_Rel*>(Begin() + section_header.sh_offset);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetRelNum(Elf_Shdr& section_header) const {
CHECK(SHT_REL == section_header.sh_type) << file_->GetPath() << " " << section_header.sh_type;
CHECK_NE(0U, section_header.sh_entsize) << file_->GetPath();
return section_header.sh_size / section_header.sh_entsize;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Rel& ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetRel(Elf_Shdr& section_header, Elf_Word i) const {
CHECK(SHT_REL == section_header.sh_type) << file_->GetPath() << " " << section_header.sh_type;
CHECK_LT(i, GetRelNum(section_header)) << file_->GetPath();
return *(GetRelSectionStart(section_header) + i);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Rela* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetRelaSectionStart(Elf_Shdr& section_header) const {
CHECK(SHT_RELA == section_header.sh_type) << file_->GetPath() << " " << section_header.sh_type;
return reinterpret_cast<Elf_Rela*>(Begin() + section_header.sh_offset);
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Word ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetRelaNum(Elf_Shdr& section_header) const {
CHECK(SHT_RELA == section_header.sh_type) << file_->GetPath() << " " << section_header.sh_type;
return section_header.sh_size / section_header.sh_entsize;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Rela& ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetRela(Elf_Shdr& section_header, Elf_Word i) const {
CHECK(SHT_RELA == section_header.sh_type) << file_->GetPath() << " " << section_header.sh_type;
CHECK_LT(i, GetRelaNum(section_header)) << file_->GetPath();
return *(GetRelaSectionStart(section_header) + i);
}
// Base on bionic phdr_table_get_load_size
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
size_t ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GetLoadedSize() const {
Elf_Addr min_vaddr = 0xFFFFFFFFu;
Elf_Addr max_vaddr = 0x00000000u;
for (Elf_Word i = 0; i < GetProgramHeaderNum(); i++) {
Elf_Phdr* program_header = GetProgramHeader(i);
if (program_header->p_type != PT_LOAD) {
continue;
}
Elf_Addr begin_vaddr = program_header->p_vaddr;
if (begin_vaddr < min_vaddr) {
min_vaddr = begin_vaddr;
}
Elf_Addr end_vaddr = program_header->p_vaddr + program_header->p_memsz;
if (end_vaddr > max_vaddr) {
max_vaddr = end_vaddr;
}
}
min_vaddr = RoundDown(min_vaddr, kPageSize);
max_vaddr = RoundUp(max_vaddr, kPageSize);
CHECK_LT(min_vaddr, max_vaddr) << file_->GetPath();
size_t loaded_size = max_vaddr - min_vaddr;
return loaded_size;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::Load(bool executable, std::string* error_msg) {
CHECK(program_header_only_) << file_->GetPath();
if (executable) {
InstructionSet elf_ISA = GetInstructionSetFromELF(GetHeader().e_machine, GetHeader().e_flags);
if (elf_ISA != kRuntimeISA) {
std::ostringstream oss;
oss << "Expected ISA " << kRuntimeISA << " but found " << elf_ISA;
*error_msg = oss.str();
return false;
}
}
bool reserved = false;
for (Elf_Word i = 0; i < GetProgramHeaderNum(); i++) {
Elf_Phdr* program_header = GetProgramHeader(i);
if (program_header == nullptr) {
*error_msg = StringPrintf("No program header for entry %d in ELF file %s.",
i, file_->GetPath().c_str());
return false;
}
// Record .dynamic header information for later use
if (program_header->p_type == PT_DYNAMIC) {
dynamic_program_header_ = program_header;
continue;
}
// Not something to load, move on.
if (program_header->p_type != PT_LOAD) {
continue;
}
// Found something to load.
// Before load the actual segments, reserve a contiguous chunk
// of required size and address for all segments, but with no
// permissions. We'll then carve that up with the proper
// permissions as we load the actual segments. If p_vaddr is
// non-zero, the segments require the specific address specified,
// which either was specified in the file because we already set
// base_address_ after the first zero segment).
int64_t temp_file_length = file_->GetLength();
if (temp_file_length < 0) {
errno = -temp_file_length;
*error_msg = StringPrintf("Failed to get length of file: '%s' fd=%d: %s",
file_->GetPath().c_str(), file_->Fd(), strerror(errno));
return false;
}
size_t file_length = static_cast<size_t>(temp_file_length);
if (!reserved) {
uint8_t* reserve_base = reinterpret_cast<uint8_t*>(program_header->p_vaddr);
uint8_t* reserve_base_override = reserve_base;
// Override the base (e.g. when compiling with --compile-pic)
if (requested_base_ != nullptr) {
reserve_base_override = requested_base_;
}
std::string reservation_name("ElfFile reservation for ");
reservation_name += file_->GetPath();
std::unique_ptr<MemMap> reserve(MemMap::MapAnonymous(reservation_name.c_str(),
reserve_base_override,
GetLoadedSize(), PROT_NONE, false, false,
error_msg));
if (reserve.get() == nullptr) {
*error_msg = StringPrintf("Failed to allocate %s: %s",
reservation_name.c_str(), error_msg->c_str());
return false;
}
reserved = true;
// Base address is the difference of actual mapped location and the p_vaddr
base_address_ = reinterpret_cast<uint8_t*>(reinterpret_cast<uintptr_t>(reserve->Begin())
- reinterpret_cast<uintptr_t>(reserve_base));
// By adding the p_vaddr of a section/symbol to base_address_ we will always get the
// dynamic memory address of where that object is actually mapped
//
// TODO: base_address_ needs to be calculated in ::Open, otherwise
// FindDynamicSymbolAddress returns the wrong values until Load is called.
segments_.push_back(reserve.release());
}
// empty segment, nothing to map
if (program_header->p_memsz == 0) {
continue;
}
uint8_t* p_vaddr = base_address_ + program_header->p_vaddr;
int prot = 0;
if (executable && ((program_header->p_flags & PF_X) != 0)) {
prot |= PROT_EXEC;
}
if ((program_header->p_flags & PF_W) != 0) {
prot |= PROT_WRITE;
}
if ((program_header->p_flags & PF_R) != 0) {
prot |= PROT_READ;
}
int flags = 0;
if (writable_) {
prot |= PROT_WRITE;
flags |= MAP_SHARED;
} else {
flags |= MAP_PRIVATE;
}
if (program_header->p_filesz > program_header->p_memsz) {
*error_msg = StringPrintf("Invalid p_filesz > p_memsz (%" PRIu64 " > %" PRIu64 "): %s",
static_cast<uint64_t>(program_header->p_filesz),
static_cast<uint64_t>(program_header->p_memsz),
file_->GetPath().c_str());
return false;
}
if (program_header->p_filesz < program_header->p_memsz &&
!IsAligned<kPageSize>(program_header->p_filesz)) {
*error_msg = StringPrintf("Unsupported unaligned p_filesz < p_memsz (%" PRIu64
" < %" PRIu64 "): %s",
static_cast<uint64_t>(program_header->p_filesz),
static_cast<uint64_t>(program_header->p_memsz),
file_->GetPath().c_str());
return false;
}
if (file_length < (program_header->p_offset + program_header->p_filesz)) {
*error_msg = StringPrintf("File size of %zd bytes not large enough to contain ELF segment "
"%d of %" PRIu64 " bytes: '%s'", file_length, i,
static_cast<uint64_t>(program_header->p_offset + program_header->p_filesz),
file_->GetPath().c_str());
return false;
}
if (program_header->p_filesz != 0u) {
std::unique_ptr<MemMap> segment(
MemMap::MapFileAtAddress(p_vaddr,
program_header->p_filesz,
prot, flags, file_->Fd(),
program_header->p_offset,
true, // implies MAP_FIXED
file_->GetPath().c_str(),
error_msg));
if (segment.get() == nullptr) {
*error_msg = StringPrintf("Failed to map ELF file segment %d from %s: %s",
i, file_->GetPath().c_str(), error_msg->c_str());
return false;
}
if (segment->Begin() != p_vaddr) {
*error_msg = StringPrintf("Failed to map ELF file segment %d from %s at expected address %p, "
"instead mapped to %p",
i, file_->GetPath().c_str(), p_vaddr, segment->Begin());
return false;
}
segments_.push_back(segment.release());
}
if (program_header->p_filesz < program_header->p_memsz) {
std::string name = StringPrintf("Zero-initialized segment %" PRIu64 " of ELF file %s",
static_cast<uint64_t>(i), file_->GetPath().c_str());
std::unique_ptr<MemMap> segment(
MemMap::MapAnonymous(name.c_str(),
p_vaddr + program_header->p_filesz,
program_header->p_memsz - program_header->p_filesz,
prot, false, true /* reuse */, error_msg));
if (segment == nullptr) {
*error_msg = StringPrintf("Failed to map zero-initialized ELF file segment %d from %s: %s",
i, file_->GetPath().c_str(), error_msg->c_str());
return false;
}
if (segment->Begin() != p_vaddr) {
*error_msg = StringPrintf("Failed to map zero-initialized ELF file segment %d from %s "
"at expected address %p, instead mapped to %p",
i, file_->GetPath().c_str(), p_vaddr, segment->Begin());
return false;
}
segments_.push_back(segment.release());
}
}
// Now that we are done loading, .dynamic should be in memory to find .dynstr, .dynsym, .hash
uint8_t* dsptr = base_address_ + GetDynamicProgramHeader().p_vaddr;
if ((dsptr < Begin() || dsptr >= End()) && !ValidPointer(dsptr)) {
*error_msg = StringPrintf("dynamic section address invalid in ELF file %s",
file_->GetPath().c_str());
return false;
}
dynamic_section_start_ = reinterpret_cast<Elf_Dyn*>(dsptr);
for (Elf_Word i = 0; i < GetDynamicNum(); i++) {
Elf_Dyn& elf_dyn = GetDynamic(i);
uint8_t* d_ptr = base_address_ + elf_dyn.d_un.d_ptr;
switch (elf_dyn.d_tag) {
case DT_HASH: {
if (!ValidPointer(d_ptr)) {
*error_msg = StringPrintf("DT_HASH value %p does not refer to a loaded ELF segment of %s",
d_ptr, file_->GetPath().c_str());
return false;
}
hash_section_start_ = reinterpret_cast<Elf_Word*>(d_ptr);
break;
}
case DT_STRTAB: {
if (!ValidPointer(d_ptr)) {
*error_msg = StringPrintf("DT_HASH value %p does not refer to a loaded ELF segment of %s",
d_ptr, file_->GetPath().c_str());
return false;
}
dynstr_section_start_ = reinterpret_cast<char*>(d_ptr);
break;
}
case DT_SYMTAB: {
if (!ValidPointer(d_ptr)) {
*error_msg = StringPrintf("DT_HASH value %p does not refer to a loaded ELF segment of %s",
d_ptr, file_->GetPath().c_str());
return false;
}
dynsym_section_start_ = reinterpret_cast<Elf_Sym*>(d_ptr);
break;
}
case DT_NULL: {
if (GetDynamicNum() != i+1) {
*error_msg = StringPrintf("DT_NULL found after %d .dynamic entries, "
"expected %d as implied by size of PT_DYNAMIC segment in %s",
i + 1, GetDynamicNum(), file_->GetPath().c_str());
return false;
}
break;
}
}
}
// Check for the existence of some sections.
if (!CheckSectionsExist(error_msg)) {
return false;
}
// Use GDB JIT support to do stack backtrace, etc.
if (executable) {
GdbJITSupport();
}
return true;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::ValidPointer(const uint8_t* start) const {
for (size_t i = 0; i < segments_.size(); ++i) {
const MemMap* segment = segments_[i];
if (segment->Begin() <= start && start < segment->End()) {
return true;
}
}
return false;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
Elf_Shdr* ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FindSectionByName(const std::string& name) const {
CHECK(!program_header_only_);
Elf_Shdr* shstrtab_sec = GetSectionNameStringSection();
if (shstrtab_sec == nullptr) {
return nullptr;
}
for (uint32_t i = 0; i < GetSectionHeaderNum(); i++) {
Elf_Shdr* shdr = GetSectionHeader(i);
if (shdr == nullptr) {
return nullptr;
}
const char* sec_name = GetString(*shstrtab_sec, shdr->sh_name);
if (sec_name == nullptr) {
continue;
}
if (name == sec_name) {
return shdr;
}
}
return nullptr;
}
struct PACKED(1) FDE32 {
uint32_t raw_length_;
uint32_t GetLength() {
return raw_length_ + sizeof(raw_length_);
}
uint32_t CIE_pointer;
uint32_t initial_location;
uint32_t address_range;
uint8_t instructions[0];
};
static FDE32* NextFDE(FDE32* frame) {
uint8_t* fde_bytes = reinterpret_cast<uint8_t*>(frame);
fde_bytes += frame->GetLength();
return reinterpret_cast<FDE32*>(fde_bytes);
}
static bool IsFDE(FDE32* frame) {
return frame->CIE_pointer != 0;
}
struct PACKED(1) FDE64 {
uint32_t raw_length_;
uint64_t extended_length_;
uint64_t GetLength() {
return extended_length_ + sizeof(raw_length_) + sizeof(extended_length_);
}
uint64_t CIE_pointer;
uint64_t initial_location;
uint64_t address_range;
uint8_t instructions[0];
};
static FDE64* NextFDE(FDE64* frame) {
uint8_t* fde_bytes = reinterpret_cast<uint8_t*>(frame);
fde_bytes += frame->GetLength();
return reinterpret_cast<FDE64*>(fde_bytes);
}
static bool IsFDE(FDE64* frame) {
return frame->CIE_pointer != 0;
}
static bool FixupEHFrame(off_t base_address_delta,
uint8_t* eh_frame, size_t eh_frame_size) {
if (*(reinterpret_cast<uint32_t*>(eh_frame)) == 0xffffffff) {
FDE64* last_frame = reinterpret_cast<FDE64*>(eh_frame + eh_frame_size);
FDE64* frame = NextFDE(reinterpret_cast<FDE64*>(eh_frame));
for (; frame < last_frame; frame = NextFDE(frame)) {
if (!IsFDE(frame)) {
return false;
}
frame->initial_location += base_address_delta;
}
return true;
} else {
FDE32* last_frame = reinterpret_cast<FDE32*>(eh_frame + eh_frame_size);
FDE32* frame = NextFDE(reinterpret_cast<FDE32*>(eh_frame));
for (; frame < last_frame; frame = NextFDE(frame)) {
if (!IsFDE(frame)) {
return false;
}
frame->initial_location += base_address_delta;
}
return true;
}
}
static uint8_t* NextLeb128(uint8_t* current) {
DecodeUnsignedLeb128(const_cast<const uint8_t**>(&current));
return current;
}
struct PACKED(1) DebugLineHeader {
uint32_t unit_length_; // TODO 32-bit specific size
uint16_t version_;
uint32_t header_length_; // TODO 32-bit specific size
uint8_t minimum_instruction_lenght_;
uint8_t maximum_operations_per_instruction_;
uint8_t default_is_stmt_;
int8_t line_base_;
uint8_t line_range_;
uint8_t opcode_base_;
uint8_t remaining_[0];
bool IsStandardOpcode(const uint8_t* op) const {
return *op != 0 && *op < opcode_base_;
}
bool IsExtendedOpcode(const uint8_t* op) const {
return *op == 0;
}
const uint8_t* GetStandardOpcodeLengths() const {
return remaining_;
}
uint8_t* GetNextOpcode(uint8_t* op) const {
if (IsExtendedOpcode(op)) {
uint8_t* length_field = op + 1;
uint32_t length = DecodeUnsignedLeb128(const_cast<const uint8_t**>(&length_field));
return length_field + length;
} else if (!IsStandardOpcode(op)) {
return op + 1;
} else if (*op == DW_LNS_fixed_advance_pc) {
return op + 1 + sizeof(uint16_t);
} else {
uint8_t num_args = GetStandardOpcodeLengths()[*op - 1];
op += 1;
for (int i = 0; i < num_args; i++) {
op = NextLeb128(op);
}
return op;
}
}
uint8_t* GetDebugLineData() const {
const uint8_t* hdr_start =
reinterpret_cast<const uint8_t*>(&header_length_) + sizeof(header_length_);
return const_cast<uint8_t*>(hdr_start + header_length_);
}
};
class DebugLineInstructionIterator FINAL {
public:
static DebugLineInstructionIterator* Create(DebugLineHeader* header, size_t section_size) {
std::unique_ptr<DebugLineInstructionIterator> line_iter(
new DebugLineInstructionIterator(header, section_size));
if (line_iter.get() == nullptr) {
return nullptr;
} else {
return line_iter.release();
}
}
~DebugLineInstructionIterator() {}
bool Next() {
if (current_instruction_ == nullptr) {
return false;
}
current_instruction_ = header_->GetNextOpcode(current_instruction_);
if (current_instruction_ >= last_instruction_) {
current_instruction_ = nullptr;
return false;
} else {
return true;
}
}
uint8_t* GetInstruction() const {
return current_instruction_;
}
bool IsExtendedOpcode() const {
return header_->IsExtendedOpcode(current_instruction_);
}
uint8_t GetOpcode() {
if (!IsExtendedOpcode()) {
return *current_instruction_;
} else {
uint8_t* len_ptr = current_instruction_ + 1;
return *NextLeb128(len_ptr);
}
}
uint8_t* GetArguments() {
if (!IsExtendedOpcode()) {
return current_instruction_ + 1;
} else {
uint8_t* len_ptr = current_instruction_ + 1;
return NextLeb128(len_ptr) + 1;
}
}
private:
DebugLineInstructionIterator(DebugLineHeader* header, size_t size)
: header_(header), last_instruction_(reinterpret_cast<uint8_t*>(header) + size),
current_instruction_(header->GetDebugLineData()) {}
DebugLineHeader* const header_;
uint8_t* const last_instruction_;
uint8_t* current_instruction_;
};
static bool FixupDebugLine(off_t base_offset_delta, DebugLineInstructionIterator* iter) {
while (iter->Next()) {
if (iter->IsExtendedOpcode() && iter->GetOpcode() == DW_LNE_set_address) {
*reinterpret_cast<uint32_t*>(iter->GetArguments()) += base_offset_delta;
}
}
return true;
}
struct PACKED(1) DebugInfoHeader {
uint32_t unit_length; // TODO 32-bit specific size
uint16_t version;
uint32_t debug_abbrev_offset; // TODO 32-bit specific size
uint8_t address_size;
};
// Returns -1 if it is variable length, which we will just disallow for now.
static int32_t FormLength(uint32_t att) {
switch (att) {
case DW_FORM_data1:
case DW_FORM_flag:
case DW_FORM_flag_present:
case DW_FORM_ref1:
return 1;
case DW_FORM_data2:
case DW_FORM_ref2:
return 2;
case DW_FORM_addr: // TODO 32-bit only
case DW_FORM_ref_addr: // TODO 32-bit only
case DW_FORM_sec_offset: // TODO 32-bit only
case DW_FORM_strp: // TODO 32-bit only
case DW_FORM_data4:
case DW_FORM_ref4:
return 4;
case DW_FORM_data8:
case DW_FORM_ref8:
case DW_FORM_ref_sig8:
return 8;
case DW_FORM_block:
case DW_FORM_block1:
case DW_FORM_block2:
case DW_FORM_block4:
case DW_FORM_exprloc:
case DW_FORM_indirect:
case DW_FORM_ref_udata:
case DW_FORM_sdata:
case DW_FORM_string:
case DW_FORM_udata:
default:
return -1;
}
}
class DebugTag FINAL {
public:
~DebugTag() {}
// Creates a new tag and moves data pointer up to the start of the next one.
// nullptr means error.
static DebugTag* Create(const uint8_t** data_pointer) {
const uint8_t* data = *data_pointer;
uint32_t index = DecodeUnsignedLeb128(&data);
std::unique_ptr<DebugTag> tag(new DebugTag(index));
tag->size_ = static_cast<uint32_t>(
reinterpret_cast<uintptr_t>(data) - reinterpret_cast<uintptr_t>(*data_pointer));
// skip the abbrev
tag->tag_ = DecodeUnsignedLeb128(&data);
tag->has_child_ = (*data == 0);
data++;
while (true) {
uint32_t attr = DecodeUnsignedLeb128(&data);
uint32_t form = DecodeUnsignedLeb128(&data);
if (attr == 0 && form == 0) {
break;
} else if (attr == 0 || form == 0) {
// Bad abbrev.
return nullptr;
}
int32_t size = FormLength(form);
if (size == -1) {
return nullptr;
}
tag->AddAttribute(attr, static_cast<uint32_t>(size));
}
*data_pointer = data;
return tag.release();
}
uint32_t GetSize() const {
return size_;
}
bool HasChild() const {
return has_child_;
}
uint32_t GetTagNumber() const {
return tag_;
}
uint32_t GetIndex() const {
return index_;
}
// Gets the offset of a particular attribute in this tag structure.
// Interpretation of the data is left to the consumer. 0 is returned if the
// tag does not contain the attribute.
uint32_t GetOffsetOf(uint32_t dwarf_attribute) const {
auto it = off_map_.find(dwarf_attribute);
if (it == off_map_.end()) {
return 0;
} else {
return it->second;
}
}
// Gets the size of attribute
uint32_t GetAttrSize(uint32_t dwarf_attribute) const {
auto it = size_map_.find(dwarf_attribute);
if (it == size_map_.end()) {
return 0;
} else {
return it->second;
}
}
private:
explicit DebugTag(uint32_t index) : index_(index), size_(0), tag_(0), has_child_(false) {}
void AddAttribute(uint32_t type, uint32_t attr_size) {
off_map_.insert(std::pair<uint32_t, uint32_t>(type, size_));
size_map_.insert(std::pair<uint32_t, uint32_t>(type, attr_size));
size_ += attr_size;
}
const uint32_t index_;
std::map<uint32_t, uint32_t> off_map_;
std::map<uint32_t, uint32_t> size_map_;
uint32_t size_;
uint32_t tag_;
bool has_child_;
};
class DebugAbbrev {
public:
~DebugAbbrev() {}
static DebugAbbrev* Create(const uint8_t* dbg_abbrev, size_t dbg_abbrev_size) {
std::unique_ptr<DebugAbbrev> abbrev(new DebugAbbrev(dbg_abbrev, dbg_abbrev + dbg_abbrev_size));
if (!abbrev->ReadAtOffset(0)) {
return nullptr;
}
return abbrev.release();
}
bool ReadAtOffset(uint32_t abbrev_offset) {
tags_.clear();
tag_list_.clear();
const uint8_t* dbg_abbrev = begin_ + abbrev_offset;
while (dbg_abbrev < end_ && *dbg_abbrev != 0) {
std::unique_ptr<DebugTag> tag(DebugTag::Create(&dbg_abbrev));
if (tag.get() == nullptr) {
return false;
} else {
tags_.insert(std::pair<uint32_t, uint32_t>(tag->GetIndex(), tag_list_.size()));
tag_list_.push_back(std::move(tag));
}
}
return true;
}
DebugTag* ReadTag(const uint8_t* entry) {
uint32_t tag_num = DecodeUnsignedLeb128(&entry);
auto it = tags_.find(tag_num);
if (it == tags_.end()) {
return nullptr;
} else {
CHECK_GT(tag_list_.size(), it->second);
return tag_list_.at(it->second).get();
}
}
private:
DebugAbbrev(const uint8_t* begin, const uint8_t* end) : begin_(begin), end_(end) {}
const uint8_t* const begin_;
const uint8_t* const end_;
std::map<uint32_t, uint32_t> tags_;
std::vector<std::unique_ptr<DebugTag>> tag_list_;
};
class DebugInfoIterator {
public:
static DebugInfoIterator* Create(DebugInfoHeader* header, size_t frame_size,
DebugAbbrev* abbrev) {
std::unique_ptr<DebugInfoIterator> iter(new DebugInfoIterator(header, frame_size, abbrev));
if (iter->GetCurrentTag() == nullptr) {
return nullptr;
} else {
return iter.release();
}
}
~DebugInfoIterator() {}
// Moves to the next DIE. Returns false if at last entry.
// TODO Handle variable length attributes.
bool next() {
if (current_entry_ == nullptr || current_tag_ == nullptr) {
return false;
}
bool reread_abbrev = false;
current_entry_ += current_tag_->GetSize();
if (reinterpret_cast<DebugInfoHeader*>(current_entry_) >= next_cu_) {
current_cu_ = next_cu_;
next_cu_ = GetNextCu(current_cu_);
current_entry_ = reinterpret_cast<uint8_t*>(current_cu_) + sizeof(DebugInfoHeader);
reread_abbrev = true;
}
if (current_entry_ >= last_entry_) {
current_entry_ = nullptr;
return false;
}
if (reread_abbrev) {
abbrev_->ReadAtOffset(current_cu_->debug_abbrev_offset);
}
current_tag_ = abbrev_->ReadTag(current_entry_);
if (current_tag_ == nullptr) {
current_entry_ = nullptr;
return false;
} else {
return true;
}
}
const DebugTag* GetCurrentTag() {
return const_cast<DebugTag*>(current_tag_);
}
uint8_t* GetPointerToField(uint8_t dwarf_field) {
if (current_tag_ == nullptr || current_entry_ == nullptr || current_entry_ >= last_entry_) {
return nullptr;
}
uint32_t off = current_tag_->GetOffsetOf(dwarf_field);
if (off == 0) {
// tag does not have that field.
return nullptr;
} else {
DCHECK_LT(off, current_tag_->GetSize());
return current_entry_ + off;
}
}
private:
static DebugInfoHeader* GetNextCu(DebugInfoHeader* hdr) {
uint8_t* hdr_byte = reinterpret_cast<uint8_t*>(hdr);
return reinterpret_cast<DebugInfoHeader*>(hdr_byte + sizeof(uint32_t) + hdr->unit_length);
}
DebugInfoIterator(DebugInfoHeader* header, size_t frame_size, DebugAbbrev* abbrev)
: abbrev_(abbrev),
current_cu_(header),
next_cu_(GetNextCu(header)),
last_entry_(reinterpret_cast<uint8_t*>(header) + frame_size),
current_entry_(reinterpret_cast<uint8_t*>(header) + sizeof(DebugInfoHeader)),
current_tag_(abbrev_->ReadTag(current_entry_)) {}
DebugAbbrev* const abbrev_;
DebugInfoHeader* current_cu_;
DebugInfoHeader* next_cu_;
uint8_t* const last_entry_;
uint8_t* current_entry_;
DebugTag* current_tag_;
};
static bool FixupDebugInfo(off_t base_address_delta, DebugInfoIterator* iter) {
do {
if (iter->GetCurrentTag()->GetAttrSize(DW_AT_low_pc) != sizeof(int32_t) ||
iter->GetCurrentTag()->GetAttrSize(DW_AT_high_pc) != sizeof(int32_t)) {
LOG(ERROR) << "DWARF information with 64 bit pointers is not supported yet.";
return false;
}
uint32_t* PC_low = reinterpret_cast<uint32_t*>(iter->GetPointerToField(DW_AT_low_pc));
uint32_t* PC_high = reinterpret_cast<uint32_t*>(iter->GetPointerToField(DW_AT_high_pc));
if (PC_low != nullptr && PC_high != nullptr) {
*PC_low += base_address_delta;
*PC_high += base_address_delta;
}
} while (iter->next());
return true;
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::FixupDebugSections(off_t base_address_delta) {
const Elf_Shdr* debug_info = FindSectionByName(".debug_info");
const Elf_Shdr* debug_abbrev = FindSectionByName(".debug_abbrev");
const Elf_Shdr* eh_frame = FindSectionByName(".eh_frame");
const Elf_Shdr* debug_str = FindSectionByName(".debug_str");
const Elf_Shdr* debug_line = FindSectionByName(".debug_line");
const Elf_Shdr* strtab_sec = FindSectionByName(".strtab");
const Elf_Shdr* symtab_sec = FindSectionByName(".symtab");
if (debug_info == nullptr || debug_abbrev == nullptr ||
debug_str == nullptr || strtab_sec == nullptr || symtab_sec == nullptr) {
// Release version of ART does not generate debug info.
return true;
}
if (base_address_delta == 0) {
return true;
}
if (eh_frame != nullptr &&
!FixupEHFrame(base_address_delta, Begin() + eh_frame->sh_offset, eh_frame->sh_size)) {
return false;
}
std::unique_ptr<DebugAbbrev> abbrev(DebugAbbrev::Create(Begin() + debug_abbrev->sh_offset,
debug_abbrev->sh_size));
if (abbrev.get() == nullptr) {
return false;
}
DebugInfoHeader* info_header =
reinterpret_cast<DebugInfoHeader*>(Begin() + debug_info->sh_offset);
std::unique_ptr<DebugInfoIterator> info_iter(DebugInfoIterator::Create(info_header,
debug_info->sh_size,
abbrev.get()));
if (info_iter.get() == nullptr) {
return false;
}
if (debug_line != nullptr) {
DebugLineHeader* line_header =
reinterpret_cast<DebugLineHeader*>(Begin() + debug_line->sh_offset);
std::unique_ptr<DebugLineInstructionIterator> line_iter(
DebugLineInstructionIterator::Create(line_header, debug_line->sh_size));
if (line_iter.get() == nullptr) {
return false;
}
if (!FixupDebugLine(base_address_delta, line_iter.get())) {
return false;
}
}
return FixupDebugInfo(base_address_delta, info_iter.get());
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
void ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::GdbJITSupport() {
// We only get here if we only are mapping the program header.
DCHECK(program_header_only_);
// Well, we need the whole file to do this.
std::string error_msg;
// Make it MAP_PRIVATE so we can just give it to gdb if all the necessary
// sections are there.
std::unique_ptr<ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>>
all_ptr(Open(const_cast<File*>(file_), PROT_READ | PROT_WRITE,
MAP_PRIVATE, &error_msg));
if (all_ptr.get() == nullptr) {
return;
}
ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>& all = *all_ptr;
// We need the eh_frame for gdb but debug info might be present without it.
const Elf_Shdr* eh_frame = all.FindSectionByName(".eh_frame");
if (eh_frame == nullptr) {
return;
}
// Do we have interesting sections?
// We need to add in a strtab and symtab to the image.
// all is MAP_PRIVATE so it can be written to freely.
// We also already have strtab and symtab so we are fine there.
Elf_Ehdr& elf_hdr = all.GetHeader();
elf_hdr.e_entry = 0;
elf_hdr.e_phoff = 0;
elf_hdr.e_phnum = 0;
elf_hdr.e_phentsize = 0;
elf_hdr.e_type = ET_EXEC;
// Since base_address_ is 0 if we are actually loaded at a known address (i.e. this is boot.oat)
// and the actual address stuff starts at in regular files this is good.
if (!all.FixupDebugSections(reinterpret_cast<intptr_t>(base_address_))) {
LOG(ERROR) << "Failed to load GDB data";
return;
}
jit_gdb_entry_ = CreateCodeEntry(all.Begin(), all.Size());
gdb_file_mapping_.reset(all_ptr.release());
}
template <typename Elf_Ehdr, typename Elf_Phdr, typename Elf_Shdr, typename Elf_Word,
typename Elf_Sword, typename Elf_Addr, typename Elf_Sym, typename Elf_Rel,
typename Elf_Rela, typename Elf_Dyn, typename Elf_Off>
bool ElfFileImpl<Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Word,
Elf_Sword, Elf_Addr, Elf_Sym, Elf_Rel, Elf_Rela, Elf_Dyn, Elf_Off>
::Strip(std::string* error_msg) {
// ELF files produced by MCLinker look roughly like this
//
// +------------+
// | Elf_Ehdr | contains number of Elf_Shdr and offset to first
// +------------+
// | Elf_Phdr | program headers
// | Elf_Phdr |
// | ... |
// | Elf_Phdr |
// +------------+
// | section | mixture of needed and unneeded sections
// +------------+
// | section |
// +------------+
// | ... |
// +------------+
// | section |
// +------------+
// | Elf_Shdr | section headers
// | Elf_Shdr |
// | ... | contains offset to section start
// | Elf_Shdr |
// +------------+
//
// To strip:
// - leave the Elf_Ehdr and Elf_Phdr values in place.
// - walk the sections making a new set of Elf_Shdr section headers for what we want to keep
// - move the sections are keeping up to fill in gaps of sections we want to strip
// - write new Elf_Shdr section headers to end of file, updating Elf_Ehdr
// - truncate rest of file
//
std::vector<Elf_Shdr> section_headers;
std::vector<Elf_Word> section_headers_original_indexes;
section_headers.reserve(GetSectionHeaderNum());
Elf_Shdr* string_section = GetSectionNameStringSection();
CHECK(string_section != nullptr);
for (Elf_Word i = 0; i < GetSectionHeaderNum(); i++) {
Elf_Shdr* sh = GetSectionHeader(i);
CHECK(sh != nullptr);
const char* name = GetString(*string_section, sh->sh_name);
if (name == nullptr) {
CHECK_EQ(0U, i);
section_headers.push_back(*sh);
section_headers_original_indexes.push_back(0);
continue;
}
if (StartsWith(name, ".debug")
|| (strcmp(name, ".strtab") == 0)
|| (strcmp(name, ".symtab") == 0)) {
continue;
}
section_headers.push_back(*sh);
section_headers_original_indexes.push_back(i);
}
CHECK_NE(0U, section_headers.size());
CHECK_EQ(section_headers.size(), section_headers_original_indexes.size());
// section 0 is the NULL section, sections start at offset of first section
CHECK(GetSectionHeader(1) != nullptr);
Elf_Off offset = GetSectionHeader(1)->sh_offset;
for (size_t i = 1; i < section_headers.size(); i++) {
Elf_Shdr& new_sh = section_headers[i];
Elf_Shdr* old_sh = GetSectionHeader(section_headers_original_indexes[i]);
CHECK(old_sh != nullptr);
CHECK_EQ(new_sh.sh_name, old_sh->sh_name);
if (old_sh->sh_addralign > 1) {
offset = RoundUp(offset, old_sh->sh_addralign);
}
if (old_sh->sh_offset == offset) {
// already in place
offset += old_sh->sh_size;
continue;
}
// shift section earlier
memmove