/* * 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_H_ #define ART_RUNTIME_ELF_FILE_H_ #include #include #include #include "base/unix_file/fd_file.h" #include "globals.h" #include "mem_map.h" #include "os.h" #include "UniquePtr.h" namespace art { // Used for compile time and runtime for ElfFile access. Because of // the need for use at runtime, cannot directly use LLVM classes such as // ELFObjectFile. class ElfFile { public: static ElfFile* Open(File* file, bool writable, bool program_header_only, std::string* error_msg); ~ElfFile(); // Load segments into memory based on PT_LOAD program headers File& GetFile() const { return *file_; } byte* Begin() { return map_->Begin(); } byte* End() { return map_->End(); } size_t Size() const { return map_->Size(); } ::llvm::ELF::Elf32_Ehdr& GetHeader(); ::llvm::ELF::Elf32_Word GetProgramHeaderNum(); ::llvm::ELF::Elf32_Phdr& GetProgramHeader(::llvm::ELF::Elf32_Word); ::llvm::ELF::Elf32_Phdr* FindProgamHeaderByType(::llvm::ELF::Elf32_Word type); ::llvm::ELF::Elf32_Word GetSectionHeaderNum(); ::llvm::ELF::Elf32_Shdr& GetSectionHeader(::llvm::ELF::Elf32_Word); ::llvm::ELF::Elf32_Shdr* FindSectionByType(::llvm::ELF::Elf32_Word type); ::llvm::ELF::Elf32_Shdr& GetSectionNameStringSection(); // Find .dynsym using .hash for more efficient lookup than FindSymbolAddress. byte* FindDynamicSymbolAddress(const std::string& symbol_name); static bool IsSymbolSectionType(::llvm::ELF::Elf32_Word section_type); ::llvm::ELF::Elf32_Word GetSymbolNum(::llvm::ELF::Elf32_Shdr&); ::llvm::ELF::Elf32_Sym& GetSymbol(::llvm::ELF::Elf32_Word section_type, ::llvm::ELF::Elf32_Word i); // 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. ::llvm::ELF::Elf32_Sym* FindSymbolByName(::llvm::ELF::Elf32_Word section_type, const std::string& symbol_name, bool build_map); // Find address of symbol in specified table, returning 0 if it is // not found. See FindSymbolByName for an explanation of build_map. ::llvm::ELF::Elf32_Addr FindSymbolAddress(::llvm::ELF::Elf32_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(::llvm::ELF::Elf32_Shdr&, ::llvm::ELF::Elf32_Word); // Lookup a string by section type. Returns NULL for special 0 offset. const char* GetString(::llvm::ELF::Elf32_Word section_type, ::llvm::ELF::Elf32_Word); ::llvm::ELF::Elf32_Word GetDynamicNum(); ::llvm::ELF::Elf32_Dyn& GetDynamic(::llvm::ELF::Elf32_Word); ::llvm::ELF::Elf32_Word FindDynamicValueByType(::llvm::ELF::Elf32_Sword type); ::llvm::ELF::Elf32_Word GetRelNum(::llvm::ELF::Elf32_Shdr&); ::llvm::ELF::Elf32_Rel& GetRel(::llvm::ELF::Elf32_Shdr&, ::llvm::ELF::Elf32_Word); ::llvm::ELF::Elf32_Word GetRelaNum(::llvm::ELF::Elf32_Shdr&); ::llvm::ELF::Elf32_Rela& GetRela(::llvm::ELF::Elf32_Shdr&, ::llvm::ELF::Elf32_Word); // Returns the expected size when the file is loaded at runtime size_t GetLoadedSize(); // Load segments into memory based on PT_LOAD program headers. // executable is true at run time, false at compile time. bool Load(bool executable, std::string* error_msg); private: ElfFile(); bool Setup(File* file, bool writable, bool program_header_only, std::string* error_msg); bool SetMap(MemMap* map, std::string* error_msg); byte* GetProgramHeadersStart(); byte* GetSectionHeadersStart(); ::llvm::ELF::Elf32_Phdr& GetDynamicProgramHeader(); ::llvm::ELF::Elf32_Dyn* GetDynamicSectionStart(); ::llvm::ELF::Elf32_Sym* GetSymbolSectionStart(::llvm::ELF::Elf32_Word section_type); const char* GetStringSectionStart(::llvm::ELF::Elf32_Word section_type); ::llvm::ELF::Elf32_Rel* GetRelSectionStart(::llvm::ELF::Elf32_Shdr&); ::llvm::ELF::Elf32_Rela* GetRelaSectionStart(::llvm::ELF::Elf32_Shdr&); ::llvm::ELF::Elf32_Word* GetHashSectionStart(); ::llvm::ELF::Elf32_Word GetHashBucketNum(); ::llvm::ELF::Elf32_Word GetHashChainNum(); ::llvm::ELF::Elf32_Word GetHashBucket(size_t i); ::llvm::ELF::Elf32_Word GetHashChain(size_t i); typedef std::map SymbolTable; SymbolTable** GetSymbolTable(::llvm::ELF::Elf32_Word section_type); File* file_; bool writable_; bool program_header_only_; // ELF header mapping. If program_header_only_ is false, will actually point to the entire elf file. UniquePtr map_; ::llvm::ELF::Elf32_Ehdr* header_; std::vector segments_; // Pointer to start of first PT_LOAD program segment after Load() when program_header_only_ is true. byte* base_address_; // The program header should always available but use GetProgramHeadersStart() to be sure. byte* program_headers_start_; // Conditionally available values. Use accessors to ensure they exist if they are required. byte* section_headers_start_; ::llvm::ELF::Elf32_Phdr* dynamic_program_header_; ::llvm::ELF::Elf32_Dyn* dynamic_section_start_; ::llvm::ELF::Elf32_Sym* symtab_section_start_; ::llvm::ELF::Elf32_Sym* dynsym_section_start_; const char* strtab_section_start_; const char* dynstr_section_start_; ::llvm::ELF::Elf32_Word* hash_section_start_; SymbolTable* symtab_symbol_table_; SymbolTable* dynsym_symbol_table_; }; } // namespace art #endif // ART_RUNTIME_ELF_FILE_H_