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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_RUNTIME_ELF_FILE_H_
     18 #define ART_RUNTIME_ELF_FILE_H_
     19 
     20 #include <memory>
     21 #include <string>
     22 
     23 #include "base/macros.h"
     24 #include "base/os.h"
     25 // Explicitly include our own elf.h to avoid Linux and other dependencies.
     26 #include "./elf.h"
     27 
     28 namespace art {
     29 template <typename ElfTypes>
     30 class ElfFileImpl;
     31 
     32 // Explicitly instantiated in elf_file.cc
     33 typedef ElfFileImpl<ElfTypes32> ElfFileImpl32;
     34 typedef ElfFileImpl<ElfTypes64> ElfFileImpl64;
     35 
     36 // Used for compile time and runtime for ElfFile access. Because of
     37 // the need for use at runtime, cannot directly use LLVM classes such as
     38 // ELFObjectFile.
     39 class ElfFile {
     40  public:
     41   static ElfFile* Open(File* file,
     42                        bool writable,
     43                        bool program_header_only,
     44                        bool low_4gb,
     45                        std::string* error_msg,
     46                        uint8_t* requested_base = nullptr);  // TODO: move arg to before error_msg.
     47   // Open with specific mmap flags, Always maps in the whole file, not just the
     48   // program header sections.
     49   static ElfFile* Open(File* file,
     50                        int mmap_prot,
     51                        int mmap_flags,
     52                        std::string* error_msg);
     53   ~ElfFile();
     54 
     55   // Load segments into memory based on PT_LOAD program headers
     56   bool Load(File* file, bool executable, bool low_4gb, std::string* error_msg);
     57 
     58   const uint8_t* FindDynamicSymbolAddress(const std::string& symbol_name) const;
     59 
     60   size_t Size() const;
     61 
     62   // The start of the memory map address range for this ELF file.
     63   uint8_t* Begin() const;
     64 
     65   // The end of the memory map address range for this ELF file.
     66   uint8_t* End() const;
     67 
     68   const std::string& GetFilePath() const;
     69 
     70   bool GetSectionOffsetAndSize(const char* section_name, uint64_t* offset, uint64_t* size) const;
     71 
     72   bool HasSection(const std::string& name) const;
     73 
     74   uint64_t FindSymbolAddress(unsigned section_type,
     75                              const std::string& symbol_name,
     76                              bool build_map);
     77 
     78   bool GetLoadedSize(size_t* size, std::string* error_msg) const;
     79 
     80   // Strip an ELF file of unneeded debugging information.
     81   // Returns true on success, false on failure.
     82   static bool Strip(File* file, std::string* error_msg);
     83 
     84   // Fixup an ELF file so that that oat header will be loaded at oat_begin.
     85   // Returns true on success, false on failure.
     86   static bool Fixup(File* file, uint64_t oat_data_begin);
     87 
     88   bool Fixup(uint64_t base_address);
     89 
     90   bool Is64Bit() const {
     91     return elf64_.get() != nullptr;
     92   }
     93 
     94   ElfFileImpl32* GetImpl32() const {
     95     return elf32_.get();
     96   }
     97 
     98   ElfFileImpl64* GetImpl64() const {
     99     return elf64_.get();
    100   }
    101 
    102  private:
    103   explicit ElfFile(ElfFileImpl32* elf32);
    104   explicit ElfFile(ElfFileImpl64* elf64);
    105 
    106   const std::unique_ptr<ElfFileImpl32> elf32_;
    107   const std::unique_ptr<ElfFileImpl64> elf64_;
    108 
    109   DISALLOW_COPY_AND_ASSIGN(ElfFile);
    110 };
    111 
    112 }  // namespace art
    113 
    114 #endif  // ART_RUNTIME_ELF_FILE_H_
    115