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
196
197
198
199
200
|
/*
* Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#if !defined(_WINDOWS) && !defined(__APPLE__)
#include <string.h>
#include <stdio.h>
#include <limits.h>
#include <new>
#include "memory/allocation.inline.hpp"
#include "utilities/decoder.hpp"
#include "utilities/elfFile.hpp"
#include "utilities/elfStringTable.hpp"
#include "utilities/elfSymbolTable.hpp"
ElfFile::ElfFile(const char* filepath) {
assert(filepath, "null file path");
memset(&m_elfHdr, 0, sizeof(m_elfHdr));
m_string_tables = NULL;
m_symbol_tables = NULL;
m_next = NULL;
m_status = NullDecoder::no_error;
int len = strlen(filepath) + 1;
m_filepath = (const char*)os::malloc(len * sizeof(char));
if (m_filepath != NULL) {
strcpy((char*)m_filepath, filepath);
m_file = fopen(filepath, "r");
if (m_file != NULL) {
load_tables();
} else {
m_status = NullDecoder::file_not_found;
}
} else {
m_status = NullDecoder::out_of_memory;
}
}
ElfFile::~ElfFile() {
if (m_string_tables != NULL) {
delete m_string_tables;
}
if (m_symbol_tables != NULL) {
delete m_symbol_tables;
}
if (m_file != NULL) {
fclose(m_file);
}
if (m_filepath != NULL) {
os::free((void*)m_filepath);
}
if (m_next != NULL) {
delete m_next;
}
};
//Check elf header to ensure the file is valid.
bool ElfFile::is_elf_file(Elf_Ehdr& hdr) {
return (ELFMAG0 == hdr.e_ident[EI_MAG0] &&
ELFMAG1 == hdr.e_ident[EI_MAG1] &&
ELFMAG2 == hdr.e_ident[EI_MAG2] &&
ELFMAG3 == hdr.e_ident[EI_MAG3] &&
ELFCLASSNONE != hdr.e_ident[EI_CLASS] &&
ELFDATANONE != hdr.e_ident[EI_DATA]);
}
bool ElfFile::load_tables() {
assert(m_file, "file not open");
assert(!NullDecoder::is_error(m_status), "already in error");
// read elf file header
if (fread(&m_elfHdr, sizeof(m_elfHdr), 1, m_file) != 1) {
m_status = NullDecoder::file_invalid;
return false;
}
if (!is_elf_file(m_elfHdr)) {
m_status = NullDecoder::file_invalid;
return false;
}
// walk elf file's section headers, and load string tables
Elf_Shdr shdr;
if (!fseek(m_file, m_elfHdr.e_shoff, SEEK_SET)) {
if (NullDecoder::is_error(m_status)) return false;
for (int index = 0; index < m_elfHdr.e_shnum; index ++) {
if (fread((void*)&shdr, sizeof(Elf_Shdr), 1, m_file) != 1) {
m_status = NullDecoder::file_invalid;
return false;
}
// string table
if (shdr.sh_type == SHT_STRTAB) {
ElfStringTable* table = new (std::nothrow) ElfStringTable(m_file, shdr, index);
if (table == NULL) {
m_status = NullDecoder::out_of_memory;
return false;
}
add_string_table(table);
} else if (shdr.sh_type == SHT_SYMTAB || shdr.sh_type == SHT_DYNSYM) {
ElfSymbolTable* table = new (std::nothrow) ElfSymbolTable(m_file, shdr);
if (table == NULL) {
m_status = NullDecoder::out_of_memory;
return false;
}
add_symbol_table(table);
}
}
}
return true;
}
bool ElfFile::decode(address addr, char* buf, int buflen, int* offset) {
// something already went wrong, just give up
if (NullDecoder::is_error(m_status)) {
return false;
}
ElfSymbolTable* symbol_table = m_symbol_tables;
int string_table_index;
int pos_in_string_table;
int off = INT_MAX;
bool found_symbol = false;
while (symbol_table != NULL) {
if (symbol_table->lookup(addr, &string_table_index, &pos_in_string_table, &off)) {
found_symbol = true;
}
symbol_table = symbol_table->m_next;
}
if (!found_symbol) return false;
ElfStringTable* string_table = get_string_table(string_table_index);
if (string_table == NULL) {
m_status = NullDecoder::file_invalid;
return false;
}
if (offset) *offset = off;
return string_table->string_at(pos_in_string_table, buf, buflen);
}
void ElfFile::add_symbol_table(ElfSymbolTable* table) {
if (m_symbol_tables == NULL) {
m_symbol_tables = table;
} else {
table->m_next = m_symbol_tables;
m_symbol_tables = table;
}
}
void ElfFile::add_string_table(ElfStringTable* table) {
if (m_string_tables == NULL) {
m_string_tables = table;
} else {
table->m_next = m_string_tables;
m_string_tables = table;
}
}
ElfStringTable* ElfFile::get_string_table(int index) {
ElfStringTable* p = m_string_tables;
while (p != NULL) {
if (p->index() == index) return p;
p = p->m_next;
}
return NULL;
}
#endif // _WINDOWS
|
