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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!
initSHNCommonDataSize(size_t SHNCommonDataSize)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:
ELFObject()58   ELFObject() : SHNCommonDataPtr(NULL), missingSymbols(false) { }
59 
60 public:
61   template <typename Archiver>
62   static ELFObject *read(Archiver &AR);
63 
getHeader()64   ELFHeaderTy const *getHeader() const {
65     return header.get();
66   }
67 
getSectionHeaderTable()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 
getMissingSymbols()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 
~ELFObject()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