| /* |
| * 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 "base/logging.h" |
| #include "base/stl_util.h" |
| #include "utils.h" |
| |
| namespace art { |
| |
| ElfFile::ElfFile() |
| : file_(NULL), |
| writable_(false), |
| program_header_only_(false), |
| header_(NULL), |
| base_address_(NULL), |
| program_headers_start_(NULL), |
| section_headers_start_(NULL), |
| dynamic_program_header_(NULL), |
| dynamic_section_start_(NULL), |
| symtab_section_start_(NULL), |
| dynsym_section_start_(NULL), |
| strtab_section_start_(NULL), |
| dynstr_section_start_(NULL), |
| hash_section_start_(NULL), |
| symtab_symbol_table_(NULL), |
| dynsym_symbol_table_(NULL) {} |
| |
| ElfFile* ElfFile::Open(File* file, bool writable, bool program_header_only, |
| std::string* error_msg) { |
| UniquePtr<ElfFile> elf_file(new ElfFile()); |
| if (!elf_file->Setup(file, writable, program_header_only, error_msg)) { |
| return nullptr; |
| } |
| return elf_file.release(); |
| } |
| |
| bool ElfFile::Setup(File* file, bool writable, bool program_header_only, std::string* error_msg) { |
| CHECK(file != NULL); |
| file_ = file; |
| writable_ = writable; |
| program_header_only_ = program_header_only; |
| |
| int prot; |
| int flags; |
| if (writable_) { |
| prot = PROT_READ | PROT_WRITE; |
| flags = MAP_SHARED; |
| } else { |
| prot = PROT_READ; |
| flags = MAP_PRIVATE; |
| } |
| 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_ == NULL) { |
| *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_; |
| } |
| |
| bool ElfFile::SetMap(MemMap* map, std::string* error_msg) { |
| if (map == NULL) { |
| // MemMap::Open should have already set an error. |
| DCHECK(!error_msg->empty()); |
| return false; |
| } |
| map_.reset(map); |
| CHECK(map_.get() != NULL) << file_->GetPath(); |
| CHECK(map_->Begin() != NULL) << 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 in %s: %c%c%c%c", |
| 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; |
| } |
| |
| |
| // TODO: remove these static_casts from enum when using -std=gnu++0x |
| CHECK_EQ(static_cast<unsigned char>(ELFCLASS32), header_->e_ident[EI_CLASS]) << file_->GetPath(); |
| CHECK_EQ(static_cast<unsigned char>(ELFDATA2LSB), header_->e_ident[EI_DATA]) << file_->GetPath(); |
| CHECK_EQ(static_cast<unsigned char>(EV_CURRENT), header_->e_ident[EI_VERSION]) << file_->GetPath(); |
| |
| // TODO: remove these static_casts from enum when using -std=gnu++0x |
| CHECK_EQ(static_cast<Elf32_Half>(ET_DYN), header_->e_type) << file_->GetPath(); |
| CHECK_EQ(static_cast<Elf32_Word>(EV_CURRENT), header_->e_version) << file_->GetPath(); |
| CHECK_EQ(0U, header_->e_entry) << file_->GetPath(); |
| |
| CHECK_NE(0U, header_->e_phoff) << file_->GetPath(); |
| CHECK_NE(0U, header_->e_shoff) << file_->GetPath(); |
| CHECK_NE(0U, header_->e_ehsize) << file_->GetPath(); |
| CHECK_NE(0U, header_->e_phentsize) << file_->GetPath(); |
| CHECK_NE(0U, header_->e_phnum) << file_->GetPath(); |
| CHECK_NE(0U, header_->e_shentsize) << file_->GetPath(); |
| CHECK_NE(0U, header_->e_shnum) << file_->GetPath(); |
| CHECK_NE(0U, header_->e_shstrndx) << file_->GetPath(); |
| CHECK_GE(header_->e_shnum, header_->e_shstrndx) << file_->GetPath(); |
| if (!program_header_only_) { |
| CHECK_GT(Size(), header_->e_phoff) << file_->GetPath(); |
| CHECK_GT(Size(), header_->e_shoff) << file_->GetPath(); |
| } |
| return true; |
| } |
| |
| |
| Elf32_Ehdr& ElfFile::GetHeader() { |
| CHECK(header_ != NULL); |
| return *header_; |
| } |
| |
| byte* ElfFile::GetProgramHeadersStart() { |
| CHECK(program_headers_start_ != NULL); |
| return program_headers_start_; |
| } |
| |
| byte* ElfFile::GetSectionHeadersStart() { |
| CHECK(section_headers_start_ != NULL); |
| return section_headers_start_; |
| } |
| |
| Elf32_Phdr& ElfFile::GetDynamicProgramHeader() { |
| CHECK(dynamic_program_header_ != NULL); |
| return *dynamic_program_header_; |
| } |
| |
| Elf32_Dyn* ElfFile::GetDynamicSectionStart() { |
| CHECK(dynamic_section_start_ != NULL); |
| return dynamic_section_start_; |
| } |
| |
| Elf32_Sym* ElfFile::GetSymbolSectionStart(Elf32_Word section_type) { |
| 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 = NULL; |
| } |
| } |
| CHECK(symbol_section_start != NULL); |
| return symbol_section_start; |
| } |
| |
| const char* ElfFile::GetStringSectionStart(Elf32_Word section_type) { |
| 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 = NULL; |
| } |
| } |
| CHECK(string_section_start != NULL); |
| return string_section_start; |
| } |
| |
| const char* ElfFile::GetString(Elf32_Word section_type, Elf32_Word i) { |
| CHECK(IsSymbolSectionType(section_type)) << file_->GetPath() << " " << section_type; |
| if (i == 0) { |
| return NULL; |
| } |
| const char* string_section_start = GetStringSectionStart(section_type); |
| const char* string = string_section_start + i; |
| return string; |
| } |
| |
| Elf32_Word* ElfFile::GetHashSectionStart() { |
| CHECK(hash_section_start_ != NULL); |
| return hash_section_start_; |
| } |
| |
| Elf32_Word ElfFile::GetHashBucketNum() { |
| return GetHashSectionStart()[0]; |
| } |
| |
| Elf32_Word ElfFile::GetHashChainNum() { |
| return GetHashSectionStart()[1]; |
| } |
| |
| Elf32_Word ElfFile::GetHashBucket(size_t i) { |
| CHECK_LT(i, GetHashBucketNum()); |
| // 0 is nbucket, 1 is nchain |
| return GetHashSectionStart()[2 + i]; |
| } |
| |
| Elf32_Word ElfFile::GetHashChain(size_t i) { |
| CHECK_LT(i, GetHashChainNum()); |
| // 0 is nbucket, 1 is nchain, & chains are after buckets |
| return GetHashSectionStart()[2 + GetHashBucketNum() + i]; |
| } |
| |
| Elf32_Word ElfFile::GetProgramHeaderNum() { |
| return GetHeader().e_phnum; |
| } |
| |
| Elf32_Phdr& ElfFile::GetProgramHeader(Elf32_Word i) { |
| 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) { |
| for (Elf32_Word i = 0; i < GetProgramHeaderNum(); i++) { |
| Elf32_Phdr& program_header = GetProgramHeader(i); |
| if (program_header.p_type == type) { |
| return &program_header; |
| } |
| } |
| return NULL; |
| } |
| |
| Elf32_Word ElfFile::GetSectionHeaderNum() { |
| return GetHeader().e_shnum; |
| } |
| |
| Elf32_Shdr& ElfFile::GetSectionHeader(Elf32_Word i) { |
| // 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) { |
| // 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 NULL; |
| } |
| |
| // 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() { |
| return GetSectionHeader(GetHeader().e_shstrndx); |
| } |
| |
| byte* ElfFile::FindDynamicSymbolAddress(const std::string& symbol_name) { |
| 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 base_address_ + symbol.st_value; |
| } |
| symbol_and_chain_index = GetHashChain(symbol_and_chain_index); |
| } |
| return NULL; |
| } |
| |
| bool ElfFile::IsSymbolSectionType(Elf32_Word section_type) { |
| return ((section_type == SHT_SYMTAB) || (section_type == SHT_DYNSYM)); |
| } |
| |
| Elf32_Word ElfFile::GetSymbolNum(Elf32_Shdr& section_header) { |
| 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) { |
| 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 NULL; |
| } |
| } |
| } |
| |
| 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 != NULL || build_map) { |
| if (*symbol_table == NULL) { |
| DCHECK(build_map); |
| *symbol_table = new SymbolTable; |
| Elf32_Shdr* symbol_section = FindSectionByType(section_type); |
| CHECK(symbol_section != NULL) << 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 == NULL) { |
| 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 != NULL); |
| SymbolTable::const_iterator it = (*symbol_table)->find(symbol_name); |
| if (it == (*symbol_table)->end()) { |
| return NULL; |
| } |
| return it->second; |
| } |
| |
| // Fall back to linear search |
| Elf32_Shdr* symbol_section = FindSectionByType(section_type); |
| CHECK(symbol_section != NULL) << 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 == NULL) { |
| continue; |
| } |
| if (symbol_name == name) { |
| return &symbol; |
| } |
| } |
| return NULL; |
| } |
| |
| 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 == NULL) { |
| return 0; |
| } |
| return symbol->st_value; |
| } |
| |
| const char* ElfFile::GetString(Elf32_Shdr& string_section, Elf32_Word i) { |
| 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 NULL; |
| } |
| 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() { |
| return GetDynamicProgramHeader().p_filesz / sizeof(Elf32_Dyn); |
| } |
| |
| Elf32_Dyn& ElfFile::GetDynamic(Elf32_Word i) { |
| CHECK_LT(i, GetDynamicNum()) << file_->GetPath(); |
| return *(GetDynamicSectionStart() + i); |
| } |
| |
| Elf32_Word ElfFile::FindDynamicValueByType(Elf32_Sword type) { |
| for (Elf32_Word i = 0; i < GetDynamicNum(); i++) { |
| Elf32_Dyn& elf_dyn = GetDynamic(i); |
| if (elf_dyn.d_tag == type) { |
| return elf_dyn.d_un.d_val; |
| } |
| } |
| return 0; |
| } |
| |
| Elf32_Rel* ElfFile::GetRelSectionStart(Elf32_Shdr& section_header) { |
| 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) { |
| 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) { |
| 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) { |
| 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) { |
| 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) { |
| 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() { |
| 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) { |
| // TODO: actually return false error |
| CHECK(program_header_only_) << file_->GetPath(); |
| 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::string error_msg; |
| UniquePtr<MemMap> reserve(MemMap::MapAnonymous(reservation_name.c_str(), |
| NULL, GetLoadedSize(), PROT_NONE, false, |
| &error_msg)); |
| CHECK(reserve.get() != NULL) << file_->GetPath() << ": " << error_msg; |
| 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 = MAP_FIXED; |
| 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; |
| } |
| UniquePtr<MemMap> segment(MemMap::MapFileAtAddress(p_vaddr, |
| program_header.p_memsz, |
| prot, flags, file_->Fd(), |
| program_header.p_offset, |
| true, |
| file_->GetPath().c_str(), |
| error_msg)); |
| CHECK(segment.get() != nullptr) << *error_msg; |
| CHECK_EQ(segment->Begin(), p_vaddr) << file_->GetPath(); |
| 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: { |
| hash_section_start_ = reinterpret_cast<Elf32_Word*>(d_ptr); |
| break; |
| } |
| case DT_STRTAB: { |
| dynstr_section_start_ = reinterpret_cast<char*>(d_ptr); |
| break; |
| } |
| case DT_SYMTAB: { |
| dynsym_section_start_ = reinterpret_cast<Elf32_Sym*>(d_ptr); |
| break; |
| } |
| case DT_NULL: { |
| CHECK_EQ(GetDynamicNum(), i+1); |
| break; |
| } |
| } |
| } |
| |
| return true; |
| } |
| |
| } // namespace art |