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Diffstat (limited to 'runtime/elf_file.h')
| -rw-r--r-- | runtime/elf_file.h | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/runtime/elf_file.h b/runtime/elf_file.h new file mode 100644 index 000000000..59ce7f5bf --- /dev/null +++ b/runtime/elf_file.h @@ -0,0 +1,174 @@ +/* + * 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_SRC_ELF_FILE_H_ +#define ART_SRC_ELF_FILE_H_ + +#include <map> +#include <vector> + +#include <llvm/Support/ELF.h> + +#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); + ~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 + bool Load(); + + private: + ElfFile(); + + bool Setup(File* file, bool writable, bool program_header_only); + + bool SetMap(MemMap* map); + + 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<std::string, ::llvm::ELF::Elf32_Sym*> 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<MemMap> map_; + ::llvm::ELF::Elf32_Ehdr* header_; + std::vector<MemMap*> 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_SRC_ELF_FILE_H_ |