| /* |
| * 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 <sys/types.h> |
| #include <unistd.h> |
| |
| #include "base/logging.h" |
| #include "base/stringprintf.h" |
| #include "base/stl_util.h" |
| #include "dwarf.h" |
| #include "leb128.h" |
| #include "utils.h" |
| #include "instruction_set.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 byte *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() { |
| __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 byte *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; |
| } |
| |
| ElfFile::ElfFile(File* file, bool writable, bool program_header_only) |
| : 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) { |
| CHECK(file != nullptr); |
| } |
| |
| ElfFile* ElfFile::Open(File* file, bool writable, bool program_header_only, |
| std::string* error_msg) { |
| std::unique_ptr<ElfFile> elf_file(new ElfFile(file, writable, program_header_only)); |
| 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(); |
| } |
| |
| ElfFile* ElfFile::Open(File* file, int prot, int flags, std::string* error_msg) { |
| std::unique_ptr<ElfFile> elf_file(new ElfFile(file, (prot & PROT_WRITE) == PROT_WRITE, false)); |
| if (!elf_file->Setup(prot, flags, error_msg)) { |
| return nullptr; |
| } |
| return elf_file.release(); |
| } |
| |
| bool ElfFile::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(Elf32_Ehdr)) { |
| *error_msg = StringPrintf("File size of %zd bytes not large enough to contain ELF header of " |
| "%zd bytes: '%s'", file_length, sizeof(Elf32_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(Elf32_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(Elf32_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; |
| } |
| } |
| |
| // Either way, the program header is relative to the elf header |
| program_headers_start_ = Begin() + GetHeader().e_phoff; |
| |
| if (!program_header_only_) { |
| // Setup section headers. |
| section_headers_start_ = Begin() + GetHeader().e_shoff; |
| |
| // 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; |
| } |
| |
| dynamic_section_start_ |
| = reinterpret_cast<Elf32_Dyn*>(Begin() + GetDynamicProgramHeader().p_offset); |
| |
| // Find other sections from section headers |
| for (Elf32_Word i = 0; i < GetSectionHeaderNum(); i++) { |
| Elf32_Shdr& section_header = GetSectionHeader(i); |
| byte* section_addr = Begin() + section_header.sh_offset; |
| switch (section_header.sh_type) { |
| case SHT_SYMTAB: { |
| symtab_section_start_ = reinterpret_cast<Elf32_Sym*>(section_addr); |
| break; |
| } |
| case SHT_DYNSYM: { |
| dynsym_section_start_ = reinterpret_cast<Elf32_Sym*>(section_addr); |
| break; |
| } |
| case SHT_STRTAB: { |
| // TODO: base these off of sh_link from .symtab and .dynsym above |
| if ((section_header.sh_flags & SHF_ALLOC) != 0) { |
| dynstr_section_start_ = reinterpret_cast<char*>(section_addr); |
| } else { |
| strtab_section_start_ = reinterpret_cast<char*>(section_addr); |
| } |
| break; |
| } |
| case SHT_DYNAMIC: { |
| if (reinterpret_cast<byte*>(dynamic_section_start_) != section_addr) { |
| 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*>(section_addr); |
| return false; |
| } |
| break; |
| } |
| case SHT_HASH: { |
| hash_section_start_ = reinterpret_cast<Elf32_Word*>(section_addr); |
| break; |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| ElfFile::~ElfFile() { |
| STLDeleteElements(&segments_); |
| delete symtab_symbol_table_; |
| delete dynsym_symbol_table_; |
| delete jit_elf_image_; |
| if (jit_gdb_entry_) { |
| UnregisterCodeEntry(jit_gdb_entry_); |
| } |
| } |
| |
| bool ElfFile::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<Elf32_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; |
| } |
| if (ELFCLASS32 != header_->e_ident[EI_CLASS]) { |
| *error_msg = StringPrintf("Failed to find expected EI_CLASS value %d in %s, found %d", |
| ELFCLASS32, |
| 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(), |
| 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 %d less than %zd in %s", |
| header_->e_phoff, |
| Size(), |
| file_->GetPath().c_str()); |
| return false; |
| } |
| if (header_->e_shoff >= Size()) { |
| *error_msg = StringPrintf("Failed to find e_shoff value %d less than %zd in %s", |
| header_->e_shoff, |
| Size(), |
| file_->GetPath().c_str()); |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| |
| Elf32_Ehdr& ElfFile::GetHeader() const { |
| CHECK(header_ != nullptr); |
| return *header_; |
| } |
| |
| byte* ElfFile::GetProgramHeadersStart() const { |
| CHECK(program_headers_start_ != nullptr); |
| return program_headers_start_; |
| } |
| |
| byte* ElfFile::GetSectionHeadersStart() const { |
| CHECK(section_headers_start_ != nullptr); |
| return section_headers_start_; |
| } |
| |
| Elf32_Phdr& ElfFile::GetDynamicProgramHeader() const { |
| CHECK(dynamic_program_header_ != nullptr); |
| return *dynamic_program_header_; |
| } |
| |
| Elf32_Dyn* ElfFile::GetDynamicSectionStart() const { |
| CHECK(dynamic_section_start_ != nullptr); |
| return dynamic_section_start_; |
| } |
| |
| Elf32_Sym* ElfFile::GetSymbolSectionStart(Elf32_Word section_type) const { |
| CHECK(IsSymbolSectionType(section_type)) << file_->GetPath() << " " << section_type; |
| Elf32_Sym* symbol_section_start; |
| switch (section_type) { |
| case SHT_SYMTAB: { |
| symbol_section_start = symtab_section_start_; |
| break; |
| } |
| case SHT_DYNSYM: { |
| symbol_section_start = dynsym_section_start_; |
| break; |
| } |
| default: { |
| LOG(FATAL) << section_type; |
| symbol_section_start = nullptr; |
| } |
| } |
| CHECK(symbol_section_start != nullptr); |
| return symbol_section_start; |
| } |
| |
| const char* ElfFile::GetStringSectionStart(Elf32_Word section_type) const { |
| CHECK(IsSymbolSectionType(section_type)) << file_->GetPath() << " " << section_type; |
| const char* string_section_start; |
| switch (section_type) { |
| case SHT_SYMTAB: { |
| string_section_start = strtab_section_start_; |
| break; |
| } |
| case SHT_DYNSYM: { |
| string_section_start = dynstr_section_start_; |
| break; |
| } |
| default: { |
| LOG(FATAL) << section_type; |
| string_section_start = nullptr; |
| } |
| } |
| CHECK(string_section_start != nullptr); |
| return string_section_start; |
| } |
| |
| const char* ElfFile::GetString(Elf32_Word section_type, Elf32_Word i) const { |
| CHECK(IsSymbolSectionType(section_type)) << file_->GetPath() << " " << section_type; |
| if (i == 0) { |
| return nullptr; |
| } |
| const char* string_section_start = GetStringSectionStart(section_type); |
| const char* string = string_section_start + i; |
| return string; |
| } |
| |
| Elf32_Word* ElfFile::GetHashSectionStart() const { |
| CHECK(hash_section_start_ != nullptr); |
| return hash_section_start_; |
| } |
| |
| Elf32_Word ElfFile::GetHashBucketNum() const { |
| return GetHashSectionStart()[0]; |
| } |
| |
| Elf32_Word ElfFile::GetHashChainNum() const { |
| return GetHashSectionStart()[1]; |
| } |
| |
| Elf32_Word ElfFile::GetHashBucket(size_t i) const { |
| CHECK_LT(i, GetHashBucketNum()); |
| // 0 is nbucket, 1 is nchain |
| return GetHashSectionStart()[2 + i]; |
| } |
| |
| Elf32_Word ElfFile::GetHashChain(size_t i) const { |
| CHECK_LT(i, GetHashChainNum()); |
| // 0 is nbucket, 1 is nchain, & chains are after buckets |
| return GetHashSectionStart()[2 + GetHashBucketNum() + i]; |
| } |
| |
| Elf32_Word ElfFile::GetProgramHeaderNum() const { |
| return GetHeader().e_phnum; |
| } |
| |
| Elf32_Phdr& ElfFile::GetProgramHeader(Elf32_Word i) const { |
| CHECK_LT(i, GetProgramHeaderNum()) << file_->GetPath(); |
| byte* program_header = GetProgramHeadersStart() + (i * GetHeader().e_phentsize); |
| CHECK_LT(program_header, End()) << file_->GetPath(); |
| return *reinterpret_cast<Elf32_Phdr*>(program_header); |
| } |
| |
| Elf32_Phdr* ElfFile::FindProgamHeaderByType(Elf32_Word type) const { |
| for (Elf32_Word i = 0; i < GetProgramHeaderNum(); i++) { |
| Elf32_Phdr& program_header = GetProgramHeader(i); |
| if (program_header.p_type == type) { |
| return &program_header; |
| } |
| } |
| return nullptr; |
| } |
| |
| Elf32_Word ElfFile::GetSectionHeaderNum() const { |
| return GetHeader().e_shnum; |
| } |
| |
| Elf32_Shdr& ElfFile::GetSectionHeader(Elf32_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(); |
| CHECK_LT(i, GetSectionHeaderNum()) << file_->GetPath(); |
| byte* section_header = GetSectionHeadersStart() + (i * GetHeader().e_shentsize); |
| CHECK_LT(section_header, End()) << file_->GetPath(); |
| return *reinterpret_cast<Elf32_Shdr*>(section_header); |
| } |
| |
| Elf32_Shdr* ElfFile::FindSectionByType(Elf32_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 (Elf32_Word i = 0; i < GetSectionHeaderNum(); i++) { |
| Elf32_Shdr& section_header = GetSectionHeader(i); |
| if (section_header.sh_type == type) { |
| return §ion_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; |
| } |
| |
| Elf32_Shdr& ElfFile::GetSectionNameStringSection() const { |
| return GetSectionHeader(GetHeader().e_shstrndx); |
| } |
| |
| const byte* ElfFile::FindDynamicSymbolAddress(const std::string& symbol_name) const { |
| const Elf32_Sym* sym = FindDynamicSymbol(symbol_name); |
| if (sym != nullptr) { |
| return base_address_ + sym->st_value; |
| } else { |
| return nullptr; |
| } |
| } |
| |
| const Elf32_Sym* ElfFile::FindDynamicSymbol(const std::string& symbol_name) const { |
| Elf32_Word hash = elfhash(symbol_name.c_str()); |
| Elf32_Word bucket_index = hash % GetHashBucketNum(); |
| Elf32_Word symbol_and_chain_index = GetHashBucket(bucket_index); |
| while (symbol_and_chain_index != 0 /* STN_UNDEF */) { |
| Elf32_Sym& symbol = GetSymbol(SHT_DYNSYM, symbol_and_chain_index); |
| const char* name = GetString(SHT_DYNSYM, symbol.st_name); |
| if (symbol_name == name) { |
| return &symbol; |
| } |
| symbol_and_chain_index = GetHashChain(symbol_and_chain_index); |
| } |
| return nullptr; |
| } |
| |
| bool ElfFile::IsSymbolSectionType(Elf32_Word section_type) { |
| return ((section_type == SHT_SYMTAB) || (section_type == SHT_DYNSYM)); |
| } |
| |
| Elf32_Word ElfFile::GetSymbolNum(Elf32_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; |
| } |
| |
| Elf32_Sym& ElfFile::GetSymbol(Elf32_Word section_type, |
| Elf32_Word i) const { |
| return *(GetSymbolSectionStart(section_type) + i); |
| } |
| |
| ElfFile::SymbolTable** ElfFile::GetSymbolTable(Elf32_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; |
| } |
| } |
| } |
| |
| Elf32_Sym* ElfFile::FindSymbolByName(Elf32_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; |
| Elf32_Shdr* symbol_section = FindSectionByType(section_type); |
| CHECK(symbol_section != nullptr) << file_->GetPath(); |
| Elf32_Shdr& string_section = GetSectionHeader(symbol_section->sh_link); |
| for (uint32_t i = 0; i < GetSymbolNum(*symbol_section); i++) { |
| Elf32_Sym& symbol = GetSymbol(section_type, i); |
| unsigned char type = 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<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. |
| CHECK_EQ(symbol.st_value, result.first->second->st_value); |
| CHECK_EQ(symbol.st_size, result.first->second->st_size); |
| CHECK_EQ(symbol.st_info, result.first->second->st_info); |
| CHECK_EQ(symbol.st_other, result.first->second->st_other); |
| CHECK_EQ(symbol.st_shndx, result.first->second->st_shndx); |
| } |
| } |
| } |
| CHECK(*symbol_table != nullptr); |
| SymbolTable::const_iterator it = (*symbol_table)->find(symbol_name); |
| if (it == (*symbol_table)->end()) { |
| return nullptr; |
| } |
| return it->second; |
| } |
| |
| // Fall back to linear search |
| Elf32_Shdr* symbol_section = FindSectionByType(section_type); |
| CHECK(symbol_section != nullptr) << file_->GetPath(); |
| Elf32_Shdr& string_section = GetSectionHeader(symbol_section->sh_link); |
| for (uint32_t i = 0; i < GetSymbolNum(*symbol_section); i++) { |
| Elf32_Sym& symbol = GetSymbol(section_type, i); |
| const char* name = GetString(string_section, symbol.st_name); |
| if (name == nullptr) { |
| continue; |
| } |
| if (symbol_name == name) { |
| return &symbol; |
| } |
| } |
| return nullptr; |
| } |
| |
| Elf32_Addr ElfFile::FindSymbolAddress(Elf32_Word section_type, |
| const std::string& symbol_name, |
| bool build_map) { |
| Elf32_Sym* symbol = FindSymbolByName(section_type, symbol_name, build_map); |
| if (symbol == nullptr) { |
| return 0; |
| } |
| return symbol->st_value; |
| } |
| |
| const char* ElfFile::GetString(Elf32_Shdr& string_section, Elf32_Word i) const { |
| CHECK(!program_header_only_) << file_->GetPath(); |
| // TODO: remove this static_cast from enum when using -std=gnu++0x |
| CHECK_EQ(static_cast<Elf32_Word>(SHT_STRTAB), string_section.sh_type) << file_->GetPath(); |
| CHECK_LT(i, string_section.sh_size) << file_->GetPath(); |
| if (i == 0) { |
| return nullptr; |
| } |
| byte* strings = Begin() + string_section.sh_offset; |
| byte* string = strings + i; |
| CHECK_LT(string, End()) << file_->GetPath(); |
| return reinterpret_cast<const char*>(string); |
| } |
| |
| Elf32_Word ElfFile::GetDynamicNum() const { |
| return GetDynamicProgramHeader().p_filesz / sizeof(Elf32_Dyn); |
| } |
| |
| Elf32_Dyn& ElfFile::GetDynamic(Elf32_Word i) const { |
| CHECK_LT(i, GetDynamicNum()) << file_->GetPath(); |
| return *(GetDynamicSectionStart() + i); |
| } |
| |
| Elf32_Dyn* ElfFile::FindDynamicByType(Elf32_Sword type) const { |
| for (Elf32_Word i = 0; i < GetDynamicNum(); i++) { |
| Elf32_Dyn* dyn = &GetDynamic(i); |
| if (dyn->d_tag == type) { |
| return dyn; |
| } |
| } |
| return NULL; |
| } |
| |
| Elf32_Word ElfFile::FindDynamicValueByType(Elf32_Sword type) const { |
| Elf32_Dyn* dyn = FindDynamicByType(type); |
| if (dyn == NULL) { |
| return 0; |
| } else { |
| return dyn->d_un.d_val; |
| } |
| } |
| |
| Elf32_Rel* ElfFile::GetRelSectionStart(Elf32_Shdr& section_header) const { |
| CHECK(SHT_REL == section_header.sh_type) << file_->GetPath() << " " << section_header.sh_type; |
| return reinterpret_cast<Elf32_Rel*>(Begin() + section_header.sh_offset); |
| } |
| |
| Elf32_Word ElfFile::GetRelNum(Elf32_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; |
| } |
| |
| Elf32_Rel& ElfFile::GetRel(Elf32_Shdr& section_header, Elf32_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); |
| } |
| |
| Elf32_Rela* ElfFile::GetRelaSectionStart(Elf32_Shdr& section_header) const { |
| CHECK(SHT_RELA == section_header.sh_type) << file_->GetPath() << " " << section_header.sh_type; |
| return reinterpret_cast<Elf32_Rela*>(Begin() + section_header.sh_offset); |
| } |
| |
| Elf32_Word ElfFile::GetRelaNum(Elf32_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; |
| } |
| |
| Elf32_Rela& ElfFile::GetRela(Elf32_Shdr& section_header, Elf32_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 |
| size_t ElfFile::GetLoadedSize() const { |
| Elf32_Addr min_vaddr = 0xFFFFFFFFu; |
| Elf32_Addr max_vaddr = 0x00000000u; |
| for (Elf32_Word i = 0; i < GetProgramHeaderNum(); i++) { |
| Elf32_Phdr& program_header = GetProgramHeader(i); |
| if (program_header.p_type != PT_LOAD) { |
| continue; |
| } |
| Elf32_Addr begin_vaddr = program_header.p_vaddr; |
| if (begin_vaddr < min_vaddr) { |
| min_vaddr = begin_vaddr; |
| } |
| Elf32_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; |
| } |
| |
| bool ElfFile::Load(bool executable, std::string* error_msg) { |
| CHECK(program_header_only_) << file_->GetPath(); |
| |
| if (executable) { |
| InstructionSet elf_ISA = kNone; |
| switch (GetHeader().e_machine) { |
| case EM_ARM: { |
| elf_ISA = kArm; |
| break; |
| } |
| case EM_AARCH64: { |
| elf_ISA = kArm64; |
| break; |
| } |
| case EM_386: { |
| elf_ISA = kX86; |
| break; |
| } |
| case EM_X86_64: { |
| elf_ISA = kX86_64; |
| break; |
| } |
| case EM_MIPS: { |
| elf_ISA = kMips; |
| break; |
| } |
| } |
| |
| if (elf_ISA != kRuntimeISA) { |
| std::ostringstream oss; |
| oss << "Expected ISA " << kRuntimeISA << " but found " << elf_ISA; |
| *error_msg = oss.str(); |
| return false; |
| } |
| } |
| |
| for (Elf32_Word i = 0; i < GetProgramHeaderNum(); i++) { |
| Elf32_Phdr& program_header = GetProgramHeader(i); |
| |
| // 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. |
| |
| // If p_vaddr is zero, it must be the first loadable segment, |
| // since they must be in order. Since it is zero, there isn't a |
| // specific address requested, so first request a contiguous chunk |
| // of required size 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 (program_header.p_vaddr == 0) { |
| std::string reservation_name("ElfFile reservation for "); |
| reservation_name += file_->GetPath(); |
| std::unique_ptr<MemMap> reserve(MemMap::MapAnonymous(reservation_name.c_str(), |
| nullptr, GetLoadedSize(), PROT_NONE, 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; |
| } |
| base_address_ = reserve->Begin(); |
| segments_.push_back(reserve.release()); |
| } |
| // empty segment, nothing to map |
| if (program_header.p_memsz == 0) { |
| continue; |
| } |
| byte* 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 (file_length < (program_header.p_offset + program_header.p_memsz)) { |
| *error_msg = StringPrintf("File size of %zd bytes not large enough to contain ELF segment " |
| "%d of %d bytes: '%s'", file_length, i, |
| program_header.p_offset + program_header.p_memsz, |
| file_->GetPath().c_str()); |
| return false; |
| } |
| std::unique_ptr<MemMap> segment(MemMap::MapFileAtAddress(p_vaddr, |
| program_header.p_memsz, |
| 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()); |
| } |
| |
| // Now that we are done loading, .dynamic should be in memory to find .dynstr, .dynsym, .hash |
| dynamic_section_start_ |
| = reinterpret_cast<Elf32_Dyn*>(base_address_ + GetDynamicProgramHeader().p_vaddr); |
| for (Elf32_Word i = 0; i < GetDynamicNum(); i++) { |
| Elf32_Dyn& elf_dyn = GetDynamic(i); |
| byte* 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<Elf32_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<Elf32_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; |
| } |
| } |
| } |
| |
| // Use GDB JIT support to do stack backtrace, etc. |
| if (executable) { |
| GdbJITSupport(); |
| } |
| |
| return true; |
| } |
| |
| bool ElfFile::ValidPointer(const byte* 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; |
| } |
| |
| |
| Elf32_Shdr* ElfFile::FindSectionByName(const std::string& name) const { |
| CHECK(!program_header_only_); |
| Elf32_Shdr& shstrtab_sec = GetSectionNameStringSection(); |
| for (uint32_t i = 0; i < GetSectionHeaderNum(); i++) { |
| Elf32_Shdr& shdr = GetSectionHeader(i); |
| 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) FDE { |
| 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 FDE* NextFDE(FDE* frame) { |
| byte* fde_bytes = reinterpret_cast<byte*>(frame); |
| fde_bytes += frame->GetLength(); |
| return reinterpret_cast<FDE*>(fde_bytes); |
| } |
| |
| static bool IsFDE(FDE* frame) { |
| // TODO This seems to be the constant everyone uses (for the .debug_frame |
| // section at least), however we should investigate this further. |
| const uint32_t kDwarfCIE_id = 0xffffffff; |
| const uint32_t kReservedLengths[] = {0xffffffff, 0xfffffff0}; |
| return frame->CIE_pointer != kDwarfCIE_id && |
| frame->raw_length_ != kReservedLengths[0] && frame->raw_length_ != kReservedLengths[1]; |
| } |
| |
| // TODO This only works for 32-bit Elf Files. |
| static bool FixupDebugFrame(uintptr_t text_start, byte* dbg_frame, size_t dbg_frame_size) { |
| FDE* last_frame = reinterpret_cast<FDE*>(dbg_frame + dbg_frame_size); |
| FDE* frame = NextFDE(reinterpret_cast<FDE*>(dbg_frame)); |
| for (; frame < last_frame; frame = NextFDE(frame)) { |
| if (!IsFDE(frame)) { |
| return false; |
| } |
| frame->initial_location += text_start; |
| } |
| 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 { |
| public: |
| const uint32_t index_; |
| ~DebugTag() {} |
| // Creates a new tag and moves data pointer up to the start of the next one. |
| // nullptr means error. |
| static DebugTag* Create(const byte** data_pointer) { |
| const byte* 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() { |
| return has_child_; |
| } |
| |
| uint32_t GetTagNumber() { |
| return tag_; |
| } |
| |
| // 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) {} |
| 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; |
| } |
| 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 byte* dbg_abbrev, size_t dbg_abbrev_size) { |
| std::unique_ptr<DebugAbbrev> abbrev(new DebugAbbrev); |
| const byte* last = dbg_abbrev + dbg_abbrev_size; |
| while (dbg_abbrev < last) { |
| std::unique_ptr<DebugTag> tag(DebugTag::Create(&dbg_abbrev)); |
| if (tag.get() == nullptr) { |
| return nullptr; |
| } else { |
| abbrev->tags_.insert(std::pair<uint32_t, uint32_t>(tag->index_, abbrev->tag_list_.size())); |
| abbrev->tag_list_.push_back(std::move(tag)); |
| } |
| } |
| return abbrev.release(); |
| } |
| |
| DebugTag* ReadTag(const byte* 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() {} |
| 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; |
| } |
| current_entry_ += current_tag_->GetSize(); |
| if (current_entry_ >= last_entry_) { |
| current_entry_ = nullptr; |
| return false; |
| } |
| 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_); |
| } |
| byte* 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: |
| DebugInfoIterator(DebugInfoHeader* header, size_t frame_size, DebugAbbrev* abbrev) |
| : abbrev_(abbrev), |
| last_entry_(reinterpret_cast<byte*>(header) + frame_size), |
| current_entry_(reinterpret_cast<byte*>(header) + sizeof(DebugInfoHeader)), |
| current_tag_(abbrev_->ReadTag(current_entry_)) {} |
| DebugAbbrev* abbrev_; |
| byte* last_entry_; |
| byte* current_entry_; |
| DebugTag* current_tag_; |
| }; |
| |
| static bool FixupDebugInfo(uint32_t text_start, DebugInfoIterator* iter) { |
| do { |
| if (iter->GetCurrentTag()->GetAttrSize(DW_AT_low_pc) != sizeof(int32_t) || |
| iter->GetCurrentTag()->GetAttrSize(DW_AT_high_pc) != sizeof(int32_t)) { |
| 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 += text_start; |
| *PC_high += text_start; |
| } |
| } while (iter->next()); |
| return true; |
| } |
| |
| static bool FixupDebugSections(const byte* dbg_abbrev, size_t dbg_abbrev_size, |
| uintptr_t text_start, |
| byte* dbg_info, size_t dbg_info_size, |
| byte* dbg_frame, size_t dbg_frame_size) { |
| std::unique_ptr<DebugAbbrev> abbrev(DebugAbbrev::Create(dbg_abbrev, dbg_abbrev_size)); |
| if (abbrev.get() == nullptr) { |
| return false; |
| } |
| std::unique_ptr<DebugInfoIterator> iter( |
| DebugInfoIterator::Create(reinterpret_cast<DebugInfoHeader*>(dbg_info), |
| dbg_info_size, abbrev.get())); |
| if (iter.get() == nullptr) { |
| return false; |
| } |
| return FixupDebugInfo(text_start, iter.get()) |
| && FixupDebugFrame(text_start, dbg_frame, dbg_frame_size); |
| } |
| |
| void ElfFile::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<ElfFile> all_ptr(Open(const_cast<File*>(file_), PROT_READ | PROT_WRITE, |
| MAP_PRIVATE, &error_msg)); |
| if (all_ptr.get() == nullptr) { |
| return; |
| } |
| ElfFile& all = *all_ptr; |
| |
| // Do we have interesting sections? |
| const Elf32_Shdr* debug_info = all.FindSectionByName(".debug_info"); |
| const Elf32_Shdr* debug_abbrev = all.FindSectionByName(".debug_abbrev"); |
| const Elf32_Shdr* debug_frame = all.FindSectionByName(".debug_frame"); |
| const Elf32_Shdr* debug_str = all.FindSectionByName(".debug_str"); |
| const Elf32_Shdr* strtab_sec = all.FindSectionByName(".strtab"); |
| const Elf32_Shdr* symtab_sec = all.FindSectionByName(".symtab"); |
| Elf32_Shdr* text_sec = all.FindSectionByName(".text"); |
| if (debug_info == nullptr || debug_abbrev == nullptr || debug_frame == nullptr || |
| debug_str == nullptr || text_sec == nullptr || strtab_sec == nullptr || symtab_sec == nullptr) { |
| return; |
| } |
| #ifdef __LP64__ |
| if (true) { |
| return; // No ELF debug support in 64bit. |
| } |
| #endif |
| // 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. |
| Elf32_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; |
| |
| text_sec->sh_type = SHT_NOBITS; |
| text_sec->sh_offset = 0; |
| |
| if (!FixupDebugSections( |
| all.Begin() + debug_abbrev->sh_offset, debug_abbrev->sh_size, text_sec->sh_addr, |
| all.Begin() + debug_info->sh_offset, debug_info->sh_size, |
| all.Begin() + debug_frame->sh_offset, debug_frame->sh_size)) { |
| LOG(ERROR) << "Failed to load GDB data"; |
| return; |
| } |
| |
| jit_gdb_entry_ = CreateCodeEntry(all.Begin(), all.Size()); |
| gdb_file_mapping_.reset(all_ptr.release()); |
| } |
| |
| } // namespace art |