| /* |
| * 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. |
| */ |
| |
| #ifndef ART_RUNTIME_ELF_FILE_IMPL_H_ |
| #define ART_RUNTIME_ELF_FILE_IMPL_H_ |
| |
| #include <map> |
| #include <memory> |
| #include <type_traits> |
| #include <vector> |
| |
| // Explicitly include our own elf.h to avoid Linux and other dependencies. |
| #include "./elf.h" |
| #include "mem_map.h" |
| |
| namespace art { |
| |
| template <typename ElfTypes> |
| class ElfFileImpl { |
| public: |
| using Elf_Addr = typename ElfTypes::Addr; |
| using Elf_Off = typename ElfTypes::Off; |
| using Elf_Half = typename ElfTypes::Half; |
| using Elf_Word = typename ElfTypes::Word; |
| using Elf_Sword = typename ElfTypes::Sword; |
| using Elf_Ehdr = typename ElfTypes::Ehdr; |
| using Elf_Shdr = typename ElfTypes::Shdr; |
| using Elf_Sym = typename ElfTypes::Sym; |
| using Elf_Rel = typename ElfTypes::Rel; |
| using Elf_Rela = typename ElfTypes::Rela; |
| using Elf_Phdr = typename ElfTypes::Phdr; |
| using Elf_Dyn = typename ElfTypes::Dyn; |
| |
| static ElfFileImpl* Open(File* file, |
| bool writable, |
| bool program_header_only, |
| bool low_4gb, |
| std::string* error_msg, |
| uint8_t* requested_base = nullptr); |
| static ElfFileImpl* Open(File* file, |
| int mmap_prot, |
| int mmap_flags, |
| bool low_4gb, |
| std::string* error_msg); |
| ~ElfFileImpl(); |
| |
| const std::string& GetFilePath() const { |
| return file_path_; |
| } |
| |
| uint8_t* Begin() const { |
| return map_->Begin(); |
| } |
| |
| uint8_t* End() const { |
| return map_->End(); |
| } |
| |
| size_t Size() const { |
| return map_->Size(); |
| } |
| |
| Elf_Ehdr& GetHeader() const; |
| |
| Elf_Word GetProgramHeaderNum() const; |
| Elf_Phdr* GetProgramHeader(Elf_Word) const; |
| |
| Elf_Word GetSectionHeaderNum() const; |
| Elf_Shdr* GetSectionHeader(Elf_Word) const; |
| Elf_Shdr* FindSectionByType(Elf_Word type) const; |
| Elf_Shdr* FindSectionByName(const std::string& name) const; |
| |
| Elf_Shdr* GetSectionNameStringSection() const; |
| |
| // Find .dynsym using .hash for more efficient lookup than FindSymbolAddress. |
| const uint8_t* FindDynamicSymbolAddress(const std::string& symbol_name) const; |
| |
| static bool IsSymbolSectionType(Elf_Word section_type); |
| Elf_Word GetSymbolNum(Elf_Shdr&) const; |
| Elf_Sym* GetSymbol(Elf_Word section_type, Elf_Word i) const; |
| |
| // Find address of symbol in specified table, returning 0 if it is |
| // not found. See FindSymbolByName for an explanation of build_map. |
| Elf_Addr FindSymbolAddress(Elf_Word section_type, |
| const std::string& symbol_name, |
| bool build_map); |
| |
| // Lookup a string given string section and offset. Returns null for special 0 offset. |
| const char* GetString(Elf_Shdr&, Elf_Word) const; |
| |
| Elf_Word GetDynamicNum() const; |
| Elf_Dyn& GetDynamic(Elf_Word) const; |
| |
| Elf_Word GetRelNum(Elf_Shdr&) const; |
| Elf_Rel& GetRel(Elf_Shdr&, Elf_Word) const; |
| |
| Elf_Word GetRelaNum(Elf_Shdr&) const; |
| Elf_Rela& GetRela(Elf_Shdr&, Elf_Word) const; |
| |
| // Retrieves the expected size when the file is loaded at runtime. Returns true if successful. |
| bool GetLoadedSize(size_t* size, std::string* error_msg) const; |
| |
| // Load segments into memory based on PT_LOAD program headers. |
| // executable is true at run time, false at compile time. |
| bool Load(File* file, bool executable, bool low_4gb, std::string* error_msg); |
| |
| bool Fixup(Elf_Addr base_address); |
| bool FixupDynamic(Elf_Addr base_address); |
| bool FixupSectionHeaders(Elf_Addr base_address); |
| bool FixupProgramHeaders(Elf_Addr base_address); |
| bool FixupSymbols(Elf_Addr base_address, bool dynamic); |
| bool FixupRelocations(Elf_Addr base_address); |
| bool FixupDebugSections(Elf_Addr base_address_delta); |
| bool ApplyOatPatchesTo(const char* target_section_name, Elf_Addr base_address_delta); |
| static void ApplyOatPatches(const uint8_t* patches, const uint8_t* patches_end, Elf_Addr delta, |
| uint8_t* to_patch, const uint8_t* to_patch_end); |
| |
| bool Strip(File* file, std::string* error_msg); |
| |
| private: |
| ElfFileImpl(File* file, bool writable, bool program_header_only, uint8_t* requested_base); |
| |
| bool Setup(File* file, int prot, int flags, bool low_4gb, std::string* error_msg); |
| |
| bool SetMap(File* file, MemMap* map, std::string* error_msg); |
| |
| uint8_t* GetProgramHeadersStart() const; |
| uint8_t* GetSectionHeadersStart() const; |
| Elf_Phdr& GetDynamicProgramHeader() const; |
| Elf_Dyn* GetDynamicSectionStart() const; |
| Elf_Sym* GetSymbolSectionStart(Elf_Word section_type) const; |
| const char* GetStringSectionStart(Elf_Word section_type) const; |
| Elf_Rel* GetRelSectionStart(Elf_Shdr&) const; |
| Elf_Rela* GetRelaSectionStart(Elf_Shdr&) const; |
| Elf_Word* GetHashSectionStart() const; |
| Elf_Word GetHashBucketNum() const; |
| Elf_Word GetHashChainNum() const; |
| Elf_Word GetHashBucket(size_t i, bool* ok) const; |
| Elf_Word GetHashChain(size_t i, bool* ok) const; |
| |
| typedef std::map<std::string, Elf_Sym*> SymbolTable; |
| SymbolTable** GetSymbolTable(Elf_Word section_type); |
| |
| bool ValidPointer(const uint8_t* start) const; |
| |
| const Elf_Sym* FindDynamicSymbol(const std::string& symbol_name) const; |
| |
| // Check that certain sections and their dependencies exist. |
| bool CheckSectionsExist(File* file, std::string* error_msg) const; |
| |
| // Check that the link of the first section links to the second section. |
| bool CheckSectionsLinked(const uint8_t* source, const uint8_t* target) const; |
| |
| // Check whether the offset is in range, and set to target to Begin() + offset if OK. |
| bool CheckAndSet(Elf32_Off offset, const char* label, uint8_t** target, std::string* error_msg); |
| |
| // Find symbol in specified table, returning null if it is not found. |
| // |
| // If build_map is true, builds a map to speed repeated access. The |
| // map does not included untyped symbol values (aka STT_NOTYPE) |
| // since they can contain duplicates. If build_map is false, the map |
| // will be used if it was already created. Typically build_map |
| // should be set unless only a small number of symbols will be |
| // looked up. |
| Elf_Sym* FindSymbolByName(Elf_Word section_type, |
| const std::string& symbol_name, |
| bool build_map); |
| |
| Elf_Phdr* FindProgamHeaderByType(Elf_Word type) const; |
| |
| Elf_Dyn* FindDynamicByType(Elf_Sword type) const; |
| Elf_Word FindDynamicValueByType(Elf_Sword type) const; |
| |
| // Lookup a string by section type. Returns null for special 0 offset. |
| const char* GetString(Elf_Word section_type, Elf_Word) const; |
| |
| const std::string file_path_; |
| const bool writable_; |
| const bool program_header_only_; |
| |
| // ELF header mapping. If program_header_only_ is false, will |
| // actually point to the entire elf file. |
| std::unique_ptr<MemMap> map_; |
| Elf_Ehdr* header_; |
| std::vector<MemMap*> segments_; |
| |
| // Pointer to start of first PT_LOAD program segment after Load() |
| // when program_header_only_ is true. |
| uint8_t* base_address_; |
| |
| // The program header should always available but use GetProgramHeadersStart() to be sure. |
| uint8_t* program_headers_start_; |
| |
| // Conditionally available values. Use accessors to ensure they exist if they are required. |
| uint8_t* section_headers_start_; |
| Elf_Phdr* dynamic_program_header_; |
| Elf_Dyn* dynamic_section_start_; |
| Elf_Sym* symtab_section_start_; |
| Elf_Sym* dynsym_section_start_; |
| char* strtab_section_start_; |
| char* dynstr_section_start_; |
| Elf_Word* hash_section_start_; |
| |
| SymbolTable* symtab_symbol_table_; |
| SymbolTable* dynsym_symbol_table_; |
| |
| // Override the 'base' p_vaddr in the first LOAD segment with this value (if non-null). |
| uint8_t* requested_base_; |
| |
| DISALLOW_COPY_AND_ASSIGN(ElfFileImpl); |
| }; |
| |
| } // namespace art |
| |
| #endif // ART_RUNTIME_ELF_FILE_IMPL_H_ |