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