| /* |
| * 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 "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 ElfTypes> |
| ElfFileImpl<ElfTypes>::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 ElfTypes> |
| ElfFileImpl<ElfTypes>* ElfFileImpl<ElfTypes>::Open( |
| File* file, bool writable, bool program_header_only, |
| std::string* error_msg, uint8_t* requested_base) { |
| std::unique_ptr<ElfFileImpl<ElfTypes>> elf_file(new ElfFileImpl<ElfTypes> |
| (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 ElfTypes> |
| ElfFileImpl<ElfTypes>* ElfFileImpl<ElfTypes>::Open( |
| File* file, int prot, int flags, std::string* error_msg) { |
| std::unique_ptr<ElfFileImpl<ElfTypes>> elf_file(new ElfFileImpl<ElfTypes> |
| (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 ElfTypes> |
| bool ElfFileImpl<ElfTypes>::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", §ion_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 ElfTypes> |
| ElfFileImpl<ElfTypes>::~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 ElfTypes> |
| bool ElfFileImpl<ElfTypes>::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 ElfTypes> |
| bool ElfFileImpl<ElfTypes>::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 ElfTypes> |
| bool ElfFileImpl<ElfTypes>::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 ElfTypes> |
| bool ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Ehdr& ElfFileImpl<ElfTypes>::GetHeader() const { |
| CHECK(header_ != nullptr); // Header has been checked in SetMap. This is a sanity check. |
| return *header_; |
| } |
| |
| template <typename ElfTypes> |
| uint8_t* ElfFileImpl<ElfTypes>::GetProgramHeadersStart() const { |
| CHECK(program_headers_start_ != nullptr); // Header has been set in Setup. This is a sanity |
| // check. |
| return program_headers_start_; |
| } |
| |
| template <typename ElfTypes> |
| uint8_t* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Phdr& ElfFileImpl<ElfTypes>::GetDynamicProgramHeader() const { |
| CHECK(dynamic_program_header_ != nullptr); // Is checked in CheckSectionsExist. Sanity check. |
| return *dynamic_program_header_; |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Dyn* ElfFileImpl<ElfTypes>::GetDynamicSectionStart() const { |
| CHECK(dynamic_section_start_ != nullptr); // Is checked in CheckSectionsExist. Sanity check. |
| return dynamic_section_start_; |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Sym* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| const char* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| const char* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Word* ElfFileImpl<ElfTypes>::GetHashSectionStart() const { |
| return hash_section_start_; |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::GetHashBucketNum() const { |
| return GetHashSectionStart()[0]; |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::GetHashChainNum() const { |
| return GetHashSectionStart()[1]; |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::GetProgramHeaderNum() const { |
| return GetHeader().e_phnum; |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Phdr* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Phdr* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::GetSectionHeaderNum() const { |
| return GetHeader().e_shnum; |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Shdr* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Shdr* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Shdr* ElfFileImpl<ElfTypes>::GetSectionNameStringSection() const { |
| return GetSectionHeader(GetHeader().e_shstrndx); |
| } |
| |
| template <typename ElfTypes> |
| const uint8_t* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| const typename ElfTypes::Sym* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| bool ElfFileImpl<ElfTypes>::IsSymbolSectionType(Elf_Word section_type) { |
| return ((section_type == SHT_SYMTAB) || (section_type == SHT_DYNSYM)); |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Sym* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfFileImpl<ElfTypes>::SymbolTable** |
| ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Sym* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Addr ElfFileImpl<ElfTypes>::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 ElfTypes> |
| const char* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::GetDynamicNum() const { |
| return GetDynamicProgramHeader().p_filesz / sizeof(Elf_Dyn); |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Dyn& ElfFileImpl<ElfTypes>::GetDynamic(Elf_Word i) const { |
| CHECK_LT(i, GetDynamicNum()) << file_->GetPath(); |
| return *(GetDynamicSectionStart() + i); |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Dyn* ElfFileImpl<ElfTypes>::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 nullptr; |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::FindDynamicValueByType(Elf_Sword type) const { |
| Elf_Dyn* dyn = FindDynamicByType(type); |
| if (dyn == nullptr) { |
| return 0; |
| } else { |
| return dyn->d_un.d_val; |
| } |
| } |
| |
| template <typename ElfTypes> |
| typename ElfTypes::Rel* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Rel& ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Rela* ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Word ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Rela& ElfFileImpl<ElfTypes>::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 ElfTypes> |
| bool ElfFileImpl<ElfTypes>::GetLoadedSize(size_t* size, std::string* error_msg) const { |
| Elf_Addr min_vaddr = static_cast<Elf_Addr>(-1); |
| Elf_Addr max_vaddr = 0u; |
| 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 (UNLIKELY(begin_vaddr > end_vaddr)) { |
| std::ostringstream oss; |
| oss << "Program header #" << i << " has overflow in p_vaddr+p_memsz: 0x" << std::hex |
| << program_header->p_vaddr << "+0x" << program_header->p_memsz << "=0x" << end_vaddr |
| << " in ELF file \"" << file_->GetPath() << "\""; |
| *error_msg = oss.str(); |
| *size = static_cast<size_t>(-1); |
| return false; |
| } |
| 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(); |
| Elf_Addr loaded_size = max_vaddr - min_vaddr; |
| // Check that the loaded_size fits in size_t. |
| if (UNLIKELY(loaded_size > std::numeric_limits<size_t>::max())) { |
| std::ostringstream oss; |
| oss << "Loaded size is 0x" << std::hex << loaded_size << " but maximum size_t is 0x" |
| << std::numeric_limits<size_t>::max() << " for ELF file \"" << file_->GetPath() << "\""; |
| *error_msg = oss.str(); |
| *size = static_cast<size_t>(-1); |
| return false; |
| } |
| *size = loaded_size; |
| return true; |
| } |
| |
| template <typename ElfTypes> |
| bool ElfFileImpl<ElfTypes>::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(); |
| size_t loaded_size; |
| if (!GetLoadedSize(&loaded_size, error_msg)) { |
| DCHECK(!error_msg->empty()); |
| return false; |
| } |
| std::unique_ptr<MemMap> reserve(MemMap::MapAnonymous(reservation_name.c_str(), |
| reserve_base_override, |
| loaded_size, 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 ElfTypes> |
| bool ElfFileImpl<ElfTypes>::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 ElfTypes> |
| typename ElfTypes::Shdr* ElfFileImpl<ElfTypes>::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; |
| } |
| |
| template <typename ElfTypes> |
| bool ElfFileImpl<ElfTypes>::FixupDebugSections(Elf_Addr base_address_delta) { |
| if (base_address_delta == 0) { |
| return true; |
| } |
| return ApplyOatPatchesTo(".debug_frame", base_address_delta) && |
| ApplyOatPatchesTo(".debug_info", base_address_delta) && |
| ApplyOatPatchesTo(".debug_line", base_address_delta); |
| } |
| |
| template <typename ElfTypes> |
| bool ElfFileImpl<ElfTypes>::ApplyOatPatchesTo( |
| const char* target_section_name, Elf_Addr delta) { |
| auto target_section = FindSectionByName(target_section_name); |
| if (target_section == nullptr) { |
| return true; |
| } |
| std::string patches_name = target_section_name + std::string(".oat_patches"); |
| auto patches_section = FindSectionByName(patches_name.c_str()); |
| if (patches_section == nullptr) { |
| LOG(ERROR) << patches_name << " section not found."; |
| return false; |
| } |
| if (patches_section->sh_type != SHT_OAT_PATCH) { |
| LOG(ERROR) << "Unexpected type of " << patches_name; |
| return false; |
| } |
| ApplyOatPatches( |
| Begin() + patches_section->sh_offset, |
| Begin() + patches_section->sh_offset + patches_section->sh_size, |
| delta, |
| Begin() + target_section->sh_offset, |
| Begin() + target_section->sh_offset + target_section->sh_size); |
| return true; |
| } |
| |
| // Apply LEB128 encoded patches to given section. |
| template <typename ElfTypes> |
| void ElfFileImpl<ElfTypes>::ApplyOatPatches( |
| const uint8_t* patches, const uint8_t* patches_end, Elf_Addr delta, |
| uint8_t* to_patch, const uint8_t* to_patch_end) { |
| typedef __attribute__((__aligned__(1))) Elf_Addr UnalignedAddress; |
| while (patches < patches_end) { |
| to_patch += DecodeUnsignedLeb128(&patches); |
| DCHECK_LE(patches, patches_end) << "Unexpected end of patch list."; |
| DCHECK_LT(to_patch, to_patch_end) << "Patch past the end of section."; |
| *reinterpret_cast<UnalignedAddress*>(to_patch) += delta; |
| } |
| } |
| |
| template <typename ElfTypes> |
| void ElfFileImpl<ElfTypes>::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<ElfTypes>> all_ptr( |
| Open(const_cast<File*>(file_), PROT_READ | PROT_WRITE, MAP_PRIVATE, &error_msg)); |
| if (all_ptr.get() == nullptr) { |
| return; |
| } |
| ElfFileImpl<ElfTypes>& 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 ElfTypes> |
| bool ElfFileImpl<ElfTypes>::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(Begin() + offset, |
| Begin() + old_sh->sh_offset, |
| old_sh->sh_size); |
| new_sh.sh_offset = offset; |
| offset += old_sh->sh_size; |
| } |
| |
| Elf_Off shoff = offset; |
| size_t section_headers_size_in_bytes = section_headers.size() * sizeof(Elf_Shdr); |
| memcpy(Begin() + offset, §ion_headers[0], section_headers_size_in_bytes); |
| offset += section_headers_size_in_bytes; |
| |
| GetHeader().e_shnum = section_headers.size(); |
| GetHeader().e_shoff = shoff; |
| int result = ftruncate(file_->Fd(), offset); |
| if (result != 0) { |
| *error_msg = StringPrintf("Failed to truncate while stripping ELF file: '%s': %s", |
| file_->GetPath().c_str(), strerror(errno)); |
| return false; |
| } |
| return true; |
| } |
| |
| static const bool DEBUG_FIXUP = false; |
| |
| template <typename ElfTypes> |
| bool ElfFileImpl<ElfTypes>::Fixup(Elf_Addr base_address) { |
| if (!FixupDynamic(base_address)) { |
| LOG(WARNING) << "Failed to fixup .dynamic in " << file_->GetPath(); |
| return false; |
| } |
| if (!FixupSectionHeaders(base_address)) { |
| LOG(WARNING) << "Failed to fixup section headers in " << file_->GetPath(); |
| return false; |
| } |
| if (!FixupProgramHeaders(base_address)) { |
| LOG(WARNING) << "Failed to fixup program headers in " << file_->GetPath(); |
| return false; |
| } |
| if (!FixupSymbols(base_address, true)) { |
| LOG(WARNING) << "Failed to fixup .dynsym in " << file_->GetPath(); |
| return false; |
| } |
| if (!FixupSymbols(base_address, false)) { |
| LOG(WARNING) << "Failed to fixup .symtab in " << file_->GetPath(); |
| return false; |
| } |
| if (!FixupRelocations(base_address)) { |
| LOG(WARNING) << "Failed to fixup .rel.dyn in " << file_->GetPath(); |
| return false; |
| } |
| static_assert(sizeof(Elf_Off) >= sizeof(base_address), "Potentially losing precision."); |
| if (!FixupDebugSections(static_cast<Elf_Off>(base_address))) { |
| LOG(WARNING) << "Failed to fixup debug sections in " << file_->GetPath(); |
| return false; |
| } |
| return true; |
| } |
| |
| template <typename ElfTypes> |
| bool ElfFileImpl<ElfTypes>::FixupDynamic(Elf_Addr base_address) { |
| for (Elf_Word i = 0; i < GetDynamicNum(); i++) { |
| Elf_Dyn& elf_dyn = GetDynamic(i); |
| Elf_Word d_tag = elf_dyn.d_tag; |
| if (IsDynamicSectionPointer(d_tag, GetHeader().e_machine)) { |
| Elf_Addr d_ptr = elf_dyn.d_un.d_ptr; |
| if (DEBUG_FIXUP) { |
| LOG(INFO) << StringPrintf("In %s moving Elf_Dyn[%d] from 0x%" PRIx64 " to 0x%" PRIx64, |
| GetFile().GetPath().c_str(), i, |
| static_cast<uint64_t>(d_ptr), |
| static_cast<uint64_t>(d_ptr + base_address)); |
| } |
| d_ptr += base_address; |
| elf_dyn.d_un.d_ptr = d_ptr; |
| } |
| } |
| return true; |
| } |
| |
| template <typename ElfTypes> |
| bool ElfFileImpl<ElfTypes>::FixupSectionHeaders(Elf_Addr base_address) { |
| for (Elf_Word i = 0; i < GetSectionHeaderNum(); i++) { |
| Elf_Shdr* sh = GetSectionHeader(i); |
| CHECK(sh != nullptr); |
| // 0 implies that the section will not exist in the memory of the process |
| if (sh->sh_addr == 0) { |
| continue; |
| } |
| if (DEBUG_FIXUP) { |
| LOG(INFO) << StringPrintf("In %s moving Elf_Shdr[%d] from 0x%" PRIx64 " to 0x%" PRIx64, |
| GetFile().GetPath().c_str(), i, |
| static_cast<uint64_t>(sh->sh_addr), |
| static_cast<uint64_t>(sh->sh_addr + base_address)); |
| } |
| sh->sh_addr += base_address; |
| } |
| return true; |
| } |
| |
| template <typename ElfTypes> |
| bool ElfFileImpl<ElfTypes>::FixupProgramHeaders(Elf_Addr base_address) { |
| // TODO: ELFObjectFile doesn't have give to Elf_Phdr, so we do that ourselves for now. |
| for (Elf_Word i = 0; i < GetProgramHeaderNum(); i++) { |
| Elf_Phdr* ph = GetProgramHeader(i); |
| CHECK(ph != nullptr); |
| CHECK_EQ(ph->p_vaddr, ph->p_paddr) << GetFile().GetPath() << " i=" << i; |
| CHECK((ph->p_align == 0) || (0 == ((ph->p_vaddr - ph->p_offset) & (ph->p_align - 1)))) |
| << GetFile().GetPath() << " i=" << i; |
| if (DEBUG_FIXUP) { |
| LOG(INFO) << StringPrintf("In %s moving Elf_Phdr[%d] from 0x%" PRIx64 " to 0x%" PRIx64, |
| GetFile().GetPath().c_str(), i, |
| static_cast<uint64_t>(ph->p_vaddr), |
| static_cast<uint64_t>(ph->p_vaddr + base_address)); |
| } |
| ph->p_vaddr += base_address; |
| ph->p_paddr += base_address; |
| CHECK((ph->p_align == 0) || (0 == ((ph->p_vaddr - ph->p_offset) & (ph->p_align - 1)))) |
| << GetFile().GetPath() << " i=" << i; |
| } |
| return true; |
| } |
| |
| template <typename ElfTypes> |
| bool ElfFileImpl<ElfTypes>::FixupSymbols(Elf_Addr base_address, bool dynamic) { |
| Elf_Word section_type = dynamic ? SHT_DYNSYM : SHT_SYMTAB; |
| // TODO: Unfortunate ELFObjectFile has protected symbol access, so use ElfFile |
| Elf_Shdr* symbol_section = FindSectionByType(section_type); |
| if (symbol_section == nullptr) { |
| // file is missing optional .symtab |
| CHECK(!dynamic) << GetFile().GetPath(); |
| return true; |
| } |
| for (uint32_t i = 0; i < GetSymbolNum(*symbol_section); i++) { |
| Elf_Sym* symbol = GetSymbol(section_type, i); |
| CHECK(symbol != nullptr); |
| if (symbol->st_value != 0) { |
| if (DEBUG_FIXUP) { |
| LOG(INFO) << StringPrintf("In %s moving Elf_Sym[%d] from 0x%" PRIx64 " to 0x%" PRIx64, |
| GetFile().GetPath().c_str(), i, |
| static_cast<uint64_t>(symbol->st_value), |
| static_cast<uint64_t>(symbol->st_value + base_address)); |
| } |
| symbol->st_value += base_address; |
| } |
| } |
| return true; |
| } |
| |
| template <typename ElfTypes> |
| bool ElfFileImpl<ElfTypes>::FixupRelocations(Elf_Addr base_address) { |
| for (Elf_Word i = 0; i < GetSectionHeaderNum(); i++) { |
| Elf_Shdr* sh = GetSectionHeader(i); |
| CHECK(sh != nullptr); |
| if (sh->sh_type == SHT_REL) { |
| for (uint32_t j = 0; j < GetRelNum(*sh); j++) { |
| Elf_Rel& rel = GetRel(*sh, j); |
| if (DEBUG_FIXUP) { |
| LOG(INFO) << StringPrintf("In %s moving Elf_Rel[%d] from 0x%" PRIx64 " to 0x%" PRIx64, |
| GetFile().GetPath().c_str(), j, |
| static_cast<uint64_t>(rel.r_offset), |
| static_cast<uint64_t>(rel.r_offset + base_address)); |
| } |
| rel.r_offset += base_address; |
| } |
| } else if (sh->sh_type == SHT_RELA) { |
| for (uint32_t j = 0; j < GetRelaNum(*sh); j++) { |
| Elf_Rela& rela = GetRela(*sh, j); |
| if (DEBUG_FIXUP) { |
| LOG(INFO) << StringPrintf("In %s moving Elf_Rela[%d] from 0x%" PRIx64 " to 0x%" PRIx64, |
| GetFile().GetPath().c_str(), j, |
| static_cast<uint64_t>(rela.r_offset), |
| static_cast<uint64_t>(rela.r_offset + base_address)); |
| } |
| rela.r_offset += base_address; |
| } |
| } |
| } |
| return true; |
| } |
| |
| // Explicit instantiations |
| template class ElfFileImpl<ElfTypes32>; |
| template class ElfFileImpl<ElfTypes64>; |
| |
| ElfFile::ElfFile(ElfFileImpl32* elf32) : elf32_(elf32), elf64_(nullptr) { |
| } |
| |
| ElfFile::ElfFile(ElfFileImpl64* elf64) : elf32_(nullptr), elf64_(elf64) { |
| } |
| |
| ElfFile::~ElfFile() { |
| // Should never have 32 and 64-bit impls. |
| CHECK_NE(elf32_.get() == nullptr, elf64_.get() == nullptr); |
| } |
| |
| ElfFile* ElfFile::Open(File* file, bool writable, bool program_header_only, std::string* error_msg, |
| uint8_t* requested_base) { |
| if (file->GetLength() < EI_NIDENT) { |
| *error_msg = StringPrintf("File %s is too short to be a valid ELF file", |
| file->GetPath().c_str()); |
| return nullptr; |
| } |
| std::unique_ptr<MemMap> map(MemMap::MapFile(EI_NIDENT, PROT_READ, MAP_PRIVATE, file->Fd(), 0, |
| file->GetPath().c_str(), error_msg)); |
| if (map == nullptr && map->Size() != EI_NIDENT) { |
| return nullptr; |
| } |
| uint8_t* header = map->Begin(); |
| if (header[EI_CLASS] == ELFCLASS64) { |
| ElfFileImpl64* elf_file_impl = ElfFileImpl64::Open(file, writable, program_header_only, |
| error_msg, requested_base); |
| if (elf_file_impl == nullptr) |
| return nullptr; |
| return new ElfFile(elf_file_impl); |
| } else if (header[EI_CLASS] == ELFCLASS32) { |
| ElfFileImpl32* elf_file_impl = ElfFileImpl32::Open(file, writable, program_header_only, |
| error_msg, requested_base); |
| if (elf_file_impl == nullptr) { |
| return nullptr; |
| } |
| return new ElfFile(elf_file_impl); |
| } else { |
| *error_msg = StringPrintf("Failed to find expected EI_CLASS value %d or %d in %s, found %d", |
| ELFCLASS32, ELFCLASS64, |
| file->GetPath().c_str(), |
| header[EI_CLASS]); |
| return nullptr; |
| } |
| } |
| |
| ElfFile* ElfFile::Open(File* file, int mmap_prot, int mmap_flags, std::string* error_msg) { |
| if (file->GetLength() < EI_NIDENT) { |
| *error_msg = StringPrintf("File %s is too short to be a valid ELF file", |
| file->GetPath().c_str()); |
| return nullptr; |
| } |
| std::unique_ptr<MemMap> map(MemMap::MapFile(EI_NIDENT, PROT_READ, MAP_PRIVATE, file->Fd(), 0, |
| file->GetPath().c_str(), error_msg)); |
| if (map == nullptr && map->Size() != EI_NIDENT) { |
| return nullptr; |
| } |
| uint8_t* header = map->Begin(); |
| if (header[EI_CLASS] == ELFCLASS64) { |
| ElfFileImpl64* elf_file_impl = ElfFileImpl64::Open(file, mmap_prot, mmap_flags, error_msg); |
| if (elf_file_impl == nullptr) { |
| return nullptr; |
| } |
| return new ElfFile(elf_file_impl); |
| } else if (header[EI_CLASS] == ELFCLASS32) { |
| ElfFileImpl32* elf_file_impl = ElfFileImpl32::Open(file, mmap_prot, mmap_flags, error_msg); |
| if (elf_file_impl == nullptr) { |
| return nullptr; |
| } |
| return new ElfFile(elf_file_impl); |
| } else { |
| *error_msg = StringPrintf("Failed to find expected EI_CLASS value %d or %d in %s, found %d", |
| ELFCLASS32, ELFCLASS64, |
| file->GetPath().c_str(), |
| header[EI_CLASS]); |
| return nullptr; |
| } |
| } |
| |
| #define DELEGATE_TO_IMPL(func, ...) \ |
| if (elf64_.get() != nullptr) { \ |
| return elf64_->func(__VA_ARGS__); \ |
| } else { \ |
| DCHECK(elf32_.get() != nullptr); \ |
| return elf32_->func(__VA_ARGS__); \ |
| } |
| |
| bool ElfFile::Load(bool executable, std::string* error_msg) { |
| DELEGATE_TO_IMPL(Load, executable, error_msg); |
| } |
| |
| const uint8_t* ElfFile::FindDynamicSymbolAddress(const std::string& symbol_name) const { |
| DELEGATE_TO_IMPL(FindDynamicSymbolAddress, symbol_name); |
| } |
| |
| size_t ElfFile::Size() const { |
| DELEGATE_TO_IMPL(Size); |
| } |
| |
| uint8_t* ElfFile::Begin() const { |
| DELEGATE_TO_IMPL(Begin); |
| } |
| |
| uint8_t* ElfFile::End() const { |
| DELEGATE_TO_IMPL(End); |
| } |
| |
| const File& ElfFile::GetFile() const { |
| DELEGATE_TO_IMPL(GetFile); |
| } |
| |
| bool ElfFile::GetSectionOffsetAndSize(const char* section_name, uint64_t* offset, uint64_t* size) { |
| if (elf32_.get() == nullptr) { |
| CHECK(elf64_.get() != nullptr); |
| |
| Elf64_Shdr *shdr = elf64_->FindSectionByName(section_name); |
| if (shdr == nullptr) { |
| return false; |
| } |
| if (offset != nullptr) { |
| *offset = shdr->sh_offset; |
| } |
| if (size != nullptr) { |
| *size = shdr->sh_size; |
| } |
| return true; |
| } else { |
| Elf32_Shdr *shdr = elf32_->FindSectionByName(section_name); |
| if (shdr == nullptr) { |
| return false; |
| } |
| if (offset != nullptr) { |
| *offset = shdr->sh_offset; |
| } |
| if (size != nullptr) { |
| *size = shdr->sh_size; |
| } |
| return true; |
| } |
| } |
| |
| uint64_t ElfFile::FindSymbolAddress(unsigned section_type, |
| const std::string& symbol_name, |
| bool build_map) { |
| DELEGATE_TO_IMPL(FindSymbolAddress, section_type, symbol_name, build_map); |
| } |
| |
| bool ElfFile::GetLoadedSize(size_t* size, std::string* error_msg) const { |
| DELEGATE_TO_IMPL(GetLoadedSize, size, error_msg); |
| } |
| |
| bool ElfFile::Strip(File* file, std::string* error_msg) { |
| std::unique_ptr<ElfFile> elf_file(ElfFile::Open(file, true, false, error_msg)); |
| if (elf_file.get() == nullptr) { |
| return false; |
| } |
| |
| if (elf_file->elf64_.get() != nullptr) |
| return elf_file->elf64_->Strip(error_msg); |
| else |
| return elf_file->elf32_->Strip(error_msg); |
| } |
| |
| bool ElfFile::Fixup(uint64_t base_address) { |
| if (elf64_.get() != nullptr) { |
| return elf64_->Fixup(static_cast<Elf64_Addr>(base_address)); |
| } else { |
| DCHECK(elf32_.get() != nullptr); |
| CHECK(IsUint<32>(base_address)) << std::hex << base_address; |
| return elf32_->Fixup(static_cast<Elf32_Addr>(base_address)); |
| } |
| DELEGATE_TO_IMPL(Fixup, base_address); |
| } |
| |
| } // namespace art |