blob: 19f9061bcead8a822aef3a7bc4329d59eff93489 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
|
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef BaseElf_h
#define BaseElf_h
#include "ElfLoader.h"
#include "Elfxx.h"
/**
* Base class for ELF libraries. This class includes things that will be
* common between SystemElfs and CustomElfs.
*/
class BaseElf: public LibHandle
{
public:
/**
* Hash function for symbol lookup, as defined in ELF standard for System V.
*/
static unsigned long Hash(const char *symbol);
/**
* Returns the address corresponding to the given symbol name (with a
* pre-computed hash).
*/
void *GetSymbolPtr(const char *symbol, unsigned long hash) const;
/**
* Returns a pointer to the Elf Symbol in the Dynamic Symbol table
* corresponding to the given symbol name (with a pre-computed hash).
*/
const Elf::Sym *GetSymbol(const char *symbol, unsigned long hash) const;
BaseElf(const char *path, Mappable *mappable = nullptr)
: LibHandle(path)
, mappable(mappable)
{
}
protected:
/**
* Inherited from LibHandle. Those are temporary and are not supposed to
* be used.
*/
virtual void *GetSymbolPtr(const char *symbol) const;
virtual bool Contains(void *addr) const;
virtual void *GetBase() const { return GetPtr(0); }
#ifdef __ARM_EABI__
virtual const void *FindExidx(int *pcount) const;
#endif
virtual Mappable *GetMappable() const { return NULL; };
public:
/* private: */
/**
* Returns a pointer relative to the base address where the library is
* loaded.
*/
void *GetPtr(const Elf::Addr offset) const
{
if (reinterpret_cast<void *>(offset) > base)
return reinterpret_cast<void *>(offset);
return base + offset;
}
/**
* Like the above, but returns a typed (const) pointer
*/
template <typename T>
const T *GetPtr(const Elf::Addr offset) const
{
if (reinterpret_cast<void *>(offset) > base)
return reinterpret_cast<const T *>(offset);
return reinterpret_cast<const T *>(base + offset);
}
/* Appropriated Mappable */
/* /!\ we rely on this being nullptr for BaseElf instances, but not
* CustomElf instances. */
RefPtr<Mappable> mappable;
/* Base address where the library is loaded */
MappedPtr base;
/* Buckets and chains for the System V symbol hash table */
Array<Elf::Word> buckets;
UnsizedArray<Elf::Word> chains;
/* protected: */
/* String table */
Elf::Strtab strtab;
/* Symbol table */
UnsizedArray<Elf::Sym> symtab;
#ifdef __ARM_EABI__
/* ARM.exidx information used by FindExidx */
Array<uint32_t[2]> arm_exidx;
#endif
};
/**
* Class for ELF libraries that already loaded in memory.
*/
class LoadedElf: public BaseElf
{
public:
/**
* Returns a LoadedElf corresponding to the already loaded ELF
* at the given base address.
*/
static already_AddRefed<LibHandle> Create(const char *path,
void *base_addr);
private:
LoadedElf(const char *path)
: BaseElf(path) { }
~LoadedElf()
{
/* Avoid base's destructor unmapping something that doesn't actually
* belong to it. */
base.release();
ElfLoader::Singleton.Forget(this);
}
/**
* Initializes the library according to information found in the given
* PT_DYNAMIC header.
* Returns whether this succeeded or failed.
*/
bool InitDyn(const Elf::Phdr *pt_dyn);
};
#endif /* BaseElf_h */
|
