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      1 /*
      2  * Copyright 2011, 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 ELF_OBJECT_H
     18 #define ELF_OBJECT_H
     19 
     20 #include "ELFTypes.h"
     21 #include "MemChunk.h"
     22 
     23 #include "utils/rsl_assert.h"
     24 
     25 #include <llvm/ADT/OwningPtr.h>
     26 
     27 #include <string>
     28 #include <vector>
     29 
     30 template <unsigned Bitwidth>
     31 class ELFObject {
     32 public:
     33   ELF_TYPE_INTRO_TO_TEMPLATE_SCOPE(Bitwidth);
     34 
     35 private:
     36   llvm::OwningPtr<ELFHeaderTy> header;
     37   llvm::OwningPtr<ELFSectionHeaderTableTy> shtab;
     38   std::vector<ELFSectionTy *> stab;
     39 
     40   MemChunk SHNCommonData;
     41   unsigned char *SHNCommonDataPtr;
     42   size_t SHNCommonDataFreeSize;
     43 
     44   bool missingSymbols;
     45 
     46   // TODO: Need refactor!
     47   bool initSHNCommonDataSize(size_t SHNCommonDataSize) {
     48     rsl_assert(!SHNCommonDataPtr && "Can't init twice.");
     49     if (!SHNCommonData.allocate(SHNCommonDataSize)) {
     50       return false;
     51     }
     52 
     53     SHNCommonDataPtr = SHNCommonData.getBuffer();
     54     SHNCommonDataFreeSize = SHNCommonDataSize;
     55     return true;
     56   }
     57 
     58 private:
     59   ELFObject() : SHNCommonDataPtr(NULL), missingSymbols(false) { }
     60 
     61 public:
     62   template <typename Archiver>
     63   static ELFObject *read(Archiver &AR);
     64 
     65   ELFHeaderTy const *getHeader() const {
     66     return header.get();
     67   }
     68 
     69   ELFSectionHeaderTableTy const *getSectionHeaderTable() const {
     70     return shtab.get();
     71   }
     72 
     73   char const *getSectionName(size_t i) const;
     74   ELFSectionTy const *getSectionByIndex(size_t i) const;
     75   ELFSectionTy *getSectionByIndex(size_t i);
     76   ELFSectionTy const *getSectionByName(std::string const &str) const;
     77   ELFSectionTy *getSectionByName(std::string const &str);
     78 
     79   inline bool getMissingSymbols() const {
     80     return missingSymbols;
     81   }
     82 
     83   void *allocateSHNCommonData(size_t size, size_t align = 1) {
     84     rsl_assert(size > 0 && align != 0);
     85 
     86     rsl_assert(SHNCommonDataPtr && "Must init common data size before use!");
     87 
     88     // Ensure alignment
     89     size_t rem = ((uintptr_t)SHNCommonDataPtr) % align;
     90     if (rem != 0) {
     91       SHNCommonDataPtr += align - rem;
     92       SHNCommonDataFreeSize -= align - rem;
     93     }
     94 
     95     // Ensure the free size is sufficient
     96     if (SHNCommonDataFreeSize < size) {
     97       return NULL;
     98     }
     99 
    100     // Allcoate
    101     void *result = SHNCommonDataPtr;
    102     SHNCommonDataPtr += size;
    103     SHNCommonDataFreeSize -= size;
    104 
    105     return result;
    106   }
    107 
    108   void relocate(void *(*find_sym)(void *context, char const *name),
    109                 void *context);
    110 
    111   void print() const;
    112 
    113   ~ELFObject() {
    114     for (size_t i = 0; i < stab.size(); ++i) {
    115       // Delete will check the pointer is nullptr or not by himself.
    116       delete stab[i];
    117     }
    118   }
    119 
    120 private:
    121   void relocateARM(void *(*find_sym)(void *context, char const *name),
    122                    void *context,
    123                    ELFSectionRelTableTy *reltab,
    124                    ELFSectionProgBitsTy *text);
    125 
    126   void relocateX86_32(void *(*find_sym)(void *context, char const *name),
    127                       void *context,
    128                       ELFSectionRelTableTy *reltab,
    129                       ELFSectionProgBitsTy *text);
    130 
    131   void relocateX86_64(void *(*find_sym)(void *context, char const *name),
    132                       void *context,
    133                       ELFSectionRelTableTy *reltab,
    134                       ELFSectionProgBitsTy *text);
    135 
    136   void relocateMIPS(void *(*find_sym)(void *context, char const *name),
    137                     void *context,
    138                     ELFSectionRelTableTy *reltab,
    139                     ELFSectionProgBitsTy *text);
    140 };
    141 
    142 #include "impl/ELFObject.hxx"
    143 
    144 #endif // ELF_OBJECT_H
    145