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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 <memory>
     26 #include <string>
     27 #include <vector>
     28 
     29 template <unsigned Bitwidth>
     30 class ELFObject {
     31 public:
     32   ELF_TYPE_INTRO_TO_TEMPLATE_SCOPE(Bitwidth);
     33 
     34 private:
     35   std::unique_ptr<ELFHeaderTy> header;
     36   std::unique_ptr<ELFSectionHeaderTableTy> shtab;
     37   std::vector<ELFSectionTy *> stab;
     38 
     39   MemChunk SHNCommonData;
     40   unsigned char *SHNCommonDataPtr;
     41   size_t SHNCommonDataFreeSize;
     42 
     43   bool missingSymbols;
     44 
     45   // TODO: Need refactor!
     46   bool initSHNCommonDataSize(size_t SHNCommonDataSize) {
     47     rsl_assert(!SHNCommonDataPtr && "Can't init twice.");
     48     if (!SHNCommonData.allocate(SHNCommonDataSize)) {
     49       return false;
     50     }
     51 
     52     SHNCommonDataPtr = SHNCommonData.getBuffer();
     53     SHNCommonDataFreeSize = SHNCommonDataSize;
     54     return true;
     55   }
     56 
     57 private:
     58   ELFObject() : SHNCommonDataPtr(NULL), missingSymbols(false) { }
     59 
     60 public:
     61   template <typename Archiver>
     62   static ELFObject *read(Archiver &AR);
     63 
     64   ELFHeaderTy const *getHeader() const {
     65     return header.get();
     66   }
     67 
     68   ELFSectionHeaderTableTy const *getSectionHeaderTable() const {
     69     return shtab.get();
     70   }
     71 
     72   char const *getSectionName(size_t i) const;
     73   ELFSectionTy const *getSectionByIndex(size_t i) const;
     74   ELFSectionTy *getSectionByIndex(size_t i);
     75   ELFSectionTy const *getSectionByName(std::string const &str) const;
     76   ELFSectionTy *getSectionByName(std::string const &str);
     77 
     78   inline bool getMissingSymbols() const {
     79     return missingSymbols;
     80   }
     81 
     82   void *allocateSHNCommonData(size_t size, size_t align = 1) {
     83     rsl_assert(size > 0 && align != 0);
     84 
     85     rsl_assert(SHNCommonDataPtr && "Must init common data size before use!");
     86 
     87     // Ensure alignment
     88     size_t rem = ((uintptr_t)SHNCommonDataPtr) % align;
     89     if (rem != 0) {
     90       SHNCommonDataPtr += align - rem;
     91       SHNCommonDataFreeSize -= align - rem;
     92     }
     93 
     94     // Ensure the free size is sufficient
     95     if (SHNCommonDataFreeSize < size) {
     96       return NULL;
     97     }
     98 
     99     // Allcoate
    100     void *result = SHNCommonDataPtr;
    101     SHNCommonDataPtr += size;
    102     SHNCommonDataFreeSize -= size;
    103 
    104     return result;
    105   }
    106 
    107   void relocate(void *(*find_sym)(void *context, char const *name),
    108                 void *context);
    109 
    110   void print() const;
    111 
    112   ~ELFObject() {
    113     for (size_t i = 0; i < stab.size(); ++i) {
    114       // Delete will check the pointer is nullptr or not by himself.
    115       delete stab[i];
    116     }
    117   }
    118 
    119 private:
    120   void relocateARM(void *(*find_sym)(void *context, char const *name),
    121                    void *context,
    122                    ELFSectionRelTableTy *reltab,
    123                    ELFSectionProgBitsTy *text);
    124 
    125   void relocateAARCH64(void *(*find_sym)(void *context, char const *name),
    126                    void *context,
    127                    ELFSectionRelTableTy *reltab,
    128                    ELFSectionProgBitsTy *text);
    129 
    130   void relocateX86_32(void *(*find_sym)(void *context, char const *name),
    131                       void *context,
    132                       ELFSectionRelTableTy *reltab,
    133                       ELFSectionProgBitsTy *text);
    134 
    135   void relocateX86_64(void *(*find_sym)(void *context, char const *name),
    136                       void *context,
    137                       ELFSectionRelTableTy *reltab,
    138                       ELFSectionProgBitsTy *text);
    139 
    140   void relocateMIPS(void *(*find_sym)(void *context, char const *name),
    141                     void *context,
    142                     ELFSectionRelTableTy *reltab,
    143                     ELFSectionProgBitsTy *text);
    144 };
    145 
    146 #include "impl/ELFObject.hxx"
    147 
    148 #endif // ELF_OBJECT_H
    149