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
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
#include <cstdio>
#include <cstring>
#include <cstdint>
#include <map>
#include <vector>
#include <string>
#include "ramscrgen.h"
#include "elf.h"
#define SHN_COMMON 0xFFF2
static std::string s_elfPath;
static FILE *s_file;
static std::uint32_t s_sectionHeaderOffset;
static int s_sectionHeaderEntrySize;
static int s_sectionCount;
static int s_shstrtabIndex;
static std::uint32_t s_symtabOffset;
static std::uint32_t s_strtabOffset;
static std::uint32_t s_symbolCount;
struct Symbol
{
std::uint32_t nameOffset;
std::uint32_t size;
};
static void Seek(long offset)
{
if (std::fseek(s_file, offset, SEEK_SET) != 0)
FATAL_ERROR("error: failed to seek to %ld in \"%s\"", offset, s_elfPath.c_str());
}
static void Skip(long offset)
{
if (std::fseek(s_file, offset, SEEK_CUR) != 0)
FATAL_ERROR("error: failed to skip %ld bytes in \"%s\"", offset, s_elfPath.c_str());
}
static std::uint32_t ReadInt8()
{
int c = std::fgetc(s_file);
if (c < 0)
FATAL_ERROR("error: unexpected EOF when reading ELF file \"%s\"\n", s_elfPath.c_str());
return c;
}
static std::uint32_t ReadInt16()
{
std::uint32_t val = 0;
val |= ReadInt8();
val |= ReadInt8() << 8;
return val;
}
static std::uint32_t ReadInt32()
{
std::uint32_t val = 0;
val |= ReadInt8();
val |= ReadInt8() << 8;
val |= ReadInt8() << 16;
val |= ReadInt8() << 24;
return val;
}
static std::string ReadString()
{
std::string s;
char c;
while ((c = ReadInt8()) != 0)
s += c;
return s;
}
static void VerifyElfIdent()
{
char expectedMagic[4] = { 0x7F, 'E', 'L', 'F' };
char magic[4];
if (std::fread(magic, 4, 1, s_file) != 1)
FATAL_ERROR("error: failed to read ELF magic from \"%s\"\n", s_elfPath.c_str());
if (std::memcmp(magic, expectedMagic, 4) != 0)
FATAL_ERROR("error: ELF magic did not match in \"%s\"\n", s_elfPath.c_str());
if (std::fgetc(s_file) != 1)
FATAL_ERROR("error: \"%s\" not 32-bit ELF\n", s_elfPath.c_str());
if (std::fgetc(s_file) != 1)
FATAL_ERROR("error: \"%s\" not little-endian ELF\n", s_elfPath.c_str());
}
static void ReadElfHeader()
{
Seek(0x20);
s_sectionHeaderOffset = ReadInt32();
Seek(0x2E);
s_sectionHeaderEntrySize = ReadInt16();
s_sectionCount = ReadInt16();
s_shstrtabIndex = ReadInt16();
}
static std::string GetSectionName(std::uint32_t shstrtabOffset, int index)
{
Seek(s_sectionHeaderOffset + s_sectionHeaderEntrySize * index);
std::uint32_t nameOffset = ReadInt32();
Seek(shstrtabOffset + nameOffset);
return ReadString();
}
static void FindTableOffsets()
{
s_symtabOffset = 0;
s_strtabOffset = 0;
Seek(s_sectionHeaderOffset + s_sectionHeaderEntrySize * s_shstrtabIndex + 0x10);
std::uint32_t shstrtabOffset = ReadInt32();
for (int i = 0; i < s_sectionCount; i++)
{
std::string name = GetSectionName(shstrtabOffset, i);
if (name == ".symtab")
{
if (s_symtabOffset)
FATAL_ERROR("error: mutiple .symtab sections found in \"%s\"\n", s_elfPath.c_str());
Seek(s_sectionHeaderOffset + s_sectionHeaderEntrySize * i + 0x10);
s_symtabOffset = ReadInt32();
std::uint32_t size = ReadInt32();
s_symbolCount = size / 16;
}
else if (name == ".strtab")
{
if (s_strtabOffset)
FATAL_ERROR("error: mutiple .strtab sections found in \"%s\"\n", s_elfPath.c_str());
Seek(s_sectionHeaderOffset + s_sectionHeaderEntrySize * i + 0x10);
s_strtabOffset = ReadInt32();
}
}
if (!s_symtabOffset)
FATAL_ERROR("error: couldn't find .symtab section in \"%s\"\n", s_elfPath.c_str());
if (!s_strtabOffset)
FATAL_ERROR("error: couldn't find .strtab section in \"%s\"\n", s_elfPath.c_str());
}
std::map<std::string, std::uint32_t> GetCommonSymbols(std::string path)
{
s_elfPath = path;
std::map<std::string, std::uint32_t> commonSymbols;
s_file = std::fopen(s_elfPath.c_str(), "rb");
if (s_file == NULL)
FATAL_ERROR("error: failed to open \"%s\" for reading\n", path.c_str());
VerifyElfIdent();
ReadElfHeader();
FindTableOffsets();
std::vector<Symbol> commonSymbolVec;
Seek(s_symtabOffset);
for (std::uint32_t i = 0; i < s_symbolCount; i++)
{
Symbol sym;
sym.nameOffset = ReadInt32();
Skip(4);
sym.size = ReadInt32();
Skip(2);
std::uint16_t sectionIndex = ReadInt16();
if (sectionIndex == SHN_COMMON)
commonSymbolVec.push_back(sym);
}
for (const Symbol& sym : commonSymbolVec)
{
Seek(s_strtabOffset + sym.nameOffset);
std::string name = ReadString();
commonSymbols[name] = sym.size;
}
return commonSymbols;
}
|
