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(m_status == Decoder::no_error, "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 (m_status != Decoder::no_error) 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 const char* ElfFile::decode(address addr, int* offset) {
144 // something already went wrong, just give up
145 if (m_status != Decoder::no_error) {
146 return NULL;
147 }
148
149 ElfSymbolTable* symbol_table = m_symbol_tables;
150 int string_table_index;
151 int pos_in_string_table;
152 int off = INT_MAX;
153 bool found_symbol = false;
154 while (symbol_table != NULL) {
155 if (Decoder::no_error == symbol_table->lookup(addr, &string_table_index, &pos_in_string_table, &off)) {
156 found_symbol = true;
157 }
158 symbol_table = symbol_table->m_next;
159 }
160 if (!found_symbol) return NULL;
161
162 ElfStringTable* string_table = get_string_table(string_table_index);
163 if (string_table == NULL) {
164 m_status = Decoder::file_invalid;
165 return NULL;
166 }
167 if (offset) *offset = off;
168 return string_table->string_at(pos_in_string_table);
169 }
170
171
172 void ElfFile::add_symbol_table(ElfSymbolTable* table) {
173 if (m_symbol_tables == NULL) {
174 m_symbol_tables = table;
175 } else {
176 table->m_next = m_symbol_tables;
177 m_symbol_tables = table;
178 }
179 }
180
181 void ElfFile::add_string_table(ElfStringTable* table) {
182 if (m_string_tables == NULL) {
183 m_string_tables = table;
184 } else {
185 table->m_next = m_string_tables;
186 m_string_tables = table;
187 }
188 }
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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 }
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