1 /*
2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26
27 #if !defined(_WINDOWS) && !defined(__APPLE__)
28
29 #include <string.h>
30 #include <stdio.h>
31 #include <limits.h>
32 #include <new>
33
34 #include "memory/allocation.inline.hpp"
35 #include "utilities/decoder.hpp"
36 #include "utilities/elfFile.hpp"
37 #include "utilities/elfStringTable.hpp"
38 #include "utilities/elfSymbolTable.hpp"
39
40
41 ElfFile::ElfFile(const char* filepath) {
42 assert(filepath, "null file path");
43 memset(&m_elfHdr, 0, sizeof(m_elfHdr));
44 m_string_tables = NULL;
45 m_symbol_tables = NULL;
46 m_next = NULL;
47 m_status = Decoder::no_error;
48
49 int len = strlen(filepath) + 1;
50 m_filepath = (const char*)os::malloc(len * sizeof(char));
51 if (m_filepath != NULL) {
52 strcpy((char*)m_filepath, filepath);
53 m_file = fopen(filepath, "r");
54 if (m_file != NULL) {
55 load_tables();
56 } else {
57 m_status = Decoder::file_not_found;
58 }
59 } else {
60 m_status = Decoder::out_of_memory;
61 }
62 }
63
64 ElfFile::~ElfFile() {
65 if (m_string_tables != NULL) {
66 delete m_string_tables;
67 }
68
69 if (m_symbol_tables != NULL) {
70 delete m_symbol_tables;
71 }
72
73 if (m_file != NULL) {
74 fclose(m_file);
75 }
76
77 if (m_filepath != NULL) {
78 os::free((void*)m_filepath);
79 }
80
81 if (m_next != NULL) {
82 delete m_next;
83 }
84 };
85
86
87 //Check elf header to ensure the file is valid.
88 bool ElfFile::is_elf_file(Elf_Ehdr& hdr) {
89 return (ELFMAG0 == hdr.e_ident[EI_MAG0] &&
90 ELFMAG1 == hdr.e_ident[EI_MAG1] &&
91 ELFMAG2 == hdr.e_ident[EI_MAG2] &&
92 ELFMAG3 == hdr.e_ident[EI_MAG3] &&
93 ELFCLASSNONE != hdr.e_ident[EI_CLASS] &&
94 ELFDATANONE != hdr.e_ident[EI_DATA]);
95 }
96
97 bool ElfFile::load_tables() {
98 assert(m_file, "file not open");
99 assert(!Decoder::is_error(m_status), "already in error");
100
101 // read elf file header
102 if (fread(&m_elfHdr, sizeof(m_elfHdr), 1, m_file) != 1) {
103 m_status = Decoder::file_invalid;
104 return false;
105 }
106
107 if (!is_elf_file(m_elfHdr)) {
108 m_status = Decoder::file_invalid;
109 return false;
110 }
111
112 // walk elf file's section headers, and load string tables
113 Elf_Shdr shdr;
114 if (!fseek(m_file, m_elfHdr.e_shoff, SEEK_SET)) {
115 if (Decoder::is_error(m_status)) return false;
116
117 for (int index = 0; index < m_elfHdr.e_shnum; index ++) {
118 if (fread((void*)&shdr, sizeof(Elf_Shdr), 1, m_file) != 1) {
119 m_status = Decoder::file_invalid;
120 return false;
121 }
122 // string table
123 if (shdr.sh_type == SHT_STRTAB) {
124 ElfStringTable* table = new (std::nothrow) ElfStringTable(m_file, shdr, index);
125 if (table == NULL) {
126 m_status = Decoder::out_of_memory;
127 return false;
128 }
129 add_string_table(table);
130 } else if (shdr.sh_type == SHT_SYMTAB || shdr.sh_type == SHT_DYNSYM) {
131 ElfSymbolTable* table = new (std::nothrow) ElfSymbolTable(m_file, shdr);
132 if (table == NULL) {
133 m_status = Decoder::out_of_memory;
134 return false;
135 }
136 add_symbol_table(table);
137 }
138 }
139 }
140 return true;
141 }
142
143 bool ElfFile::decode(address addr, char* buf, int buflen, int* offset) {
144 // something already went wrong, just give up
145 if (Decoder::is_error(m_status)) {
146 return false;
147 }
148 ElfSymbolTable* symbol_table = m_symbol_tables;
149 int string_table_index;
150 int pos_in_string_table;
151 int off = INT_MAX;
152 bool found_symbol = false;
153 while (symbol_table != NULL) {
154 if (symbol_table->lookup(addr, &string_table_index, &pos_in_string_table, &off)) {
155 found_symbol = true;
156 }
157 symbol_table = symbol_table->m_next;
158 }
159 if (!found_symbol) return false;
160
161 ElfStringTable* string_table = get_string_table(string_table_index);
162
163 if (string_table == NULL) {
164 m_status = Decoder::file_invalid;
165 return false;
166 }
167 if (offset) *offset = off;
168
169 return string_table->string_at(pos_in_string_table, buf, buflen);
170 }
171
172
173 void ElfFile::add_symbol_table(ElfSymbolTable* table) {
174 if (m_symbol_tables == NULL) {
175 m_symbol_tables = table;
176 } else {
177 table->m_next = m_symbol_tables;
178 m_symbol_tables = table;
179 }
180 }
181
182 void ElfFile::add_string_table(ElfStringTable* table) {
183 if (m_string_tables == NULL) {
184 m_string_tables = table;
185 } else {
186 table->m_next = m_string_tables;
187 m_string_tables = table;
188 }
189 }
190
191 ElfStringTable* ElfFile::get_string_table(int index) {
192 ElfStringTable* p = m_string_tables;
193 while (p != NULL) {
194 if (p->index() == index) return p;
195 p = p->m_next;
196 }
197 return NULL;
198 }
199
200 #endif // _WINDOWS