| /* |
| * Copyright (c) 1997, 2018, 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 "logging/log.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "utilities/decoder.hpp" |
| #include "utilities/elfFile.hpp" |
| #include "utilities/elfFuncDescTable.hpp" |
| #include "utilities/elfStringTable.hpp" |
| #include "utilities/elfSymbolTable.hpp" |
| #include "utilities/ostream.hpp" |
| |
| // For test only, disable elf section cache and force to read from file directly. |
| bool ElfFile::_do_not_cache_elf_section = false; |
| |
| ElfSection::ElfSection(FILE* fd, const Elf_Shdr& hdr) : _section_data(NULL) { |
| _stat = load_section(fd, hdr); |
| } |
| |
| ElfSection::~ElfSection() { |
| if (_section_data != NULL) { |
| os::free(_section_data); |
| } |
| } |
| |
| NullDecoder::decoder_status ElfSection::load_section(FILE* const fd, const Elf_Shdr& shdr) { |
| memcpy((void*)&_section_hdr, (const void*)&shdr, sizeof(shdr)); |
| |
| if (ElfFile::_do_not_cache_elf_section) { |
| log_debug(decoder)("Elf section cache is disabled"); |
| return NullDecoder::no_error; |
| } |
| |
| _section_data = os::malloc(shdr.sh_size, mtInternal); |
| // No enough memory for caching. It is okay, we can try to read from |
| // file instead. |
| if (_section_data == NULL) return NullDecoder::no_error; |
| |
| MarkedFileReader mfd(fd); |
| if (mfd.has_mark() && |
| mfd.set_position(shdr.sh_offset) && |
| mfd.read(_section_data, shdr.sh_size)) { |
| return NullDecoder::no_error; |
| } else { |
| os::free(_section_data); |
| _section_data = NULL; |
| return NullDecoder::file_invalid; |
| } |
| } |
| |
| bool FileReader::read(void* buf, size_t size) { |
| assert(buf != NULL, "no buffer"); |
| assert(size > 0, "no space"); |
| return fread(buf, size, 1, _fd) == 1; |
| } |
| |
| int FileReader::read_buffer(void* buf, size_t size) { |
| assert(buf != NULL, "no buffer"); |
| assert(size > 0, "no space"); |
| return fread(buf, 1, size, _fd); |
| } |
| |
| bool FileReader::set_position(long offset) { |
| return fseek(_fd, offset, SEEK_SET) == 0; |
| } |
| |
| MarkedFileReader::MarkedFileReader(FILE* fd) : FileReader(fd) { |
| _marked_pos = ftell(fd); |
| } |
| |
| MarkedFileReader::~MarkedFileReader() { |
| if (_marked_pos != -1) { |
| set_position(_marked_pos); |
| } |
| } |
| |
| ElfFile::ElfFile(const char* filepath) : |
| _string_tables(NULL), _symbol_tables(NULL), _funcDesc_table(NULL), |
| _next(NULL), _status(NullDecoder::no_error), |
| _shdr_string_table(NULL), _file(NULL), _filepath(NULL) { |
| memset(&_elfHdr, 0, sizeof(_elfHdr)); |
| |
| int len = strlen(filepath) + 1; |
| _filepath = (char*)os::malloc(len * sizeof(char), mtInternal); |
| if (_filepath == NULL) { |
| _status = NullDecoder::out_of_memory; |
| return; |
| } |
| strcpy(_filepath, filepath); |
| |
| _status = parse_elf(filepath); |
| |
| // we no longer need section header string table |
| if (_shdr_string_table != NULL) { |
| delete _shdr_string_table; |
| _shdr_string_table = NULL; |
| } |
| } |
| |
| ElfFile::~ElfFile() { |
| if (_shdr_string_table != NULL) { |
| delete _shdr_string_table; |
| } |
| |
| cleanup_tables(); |
| |
| if (_file != NULL) { |
| fclose(_file); |
| } |
| |
| if (_filepath != NULL) { |
| os::free((void*)_filepath); |
| } |
| |
| if (_next != NULL) { |
| delete _next; |
| } |
| } |
| |
| void ElfFile::cleanup_tables() { |
| if (_string_tables != NULL) { |
| delete _string_tables; |
| _string_tables = NULL; |
| } |
| |
| if (_symbol_tables != NULL) { |
| delete _symbol_tables; |
| _symbol_tables = NULL; |
| } |
| |
| if (_funcDesc_table != NULL) { |
| delete _funcDesc_table; |
| _funcDesc_table = NULL; |
| } |
| } |
| |
| NullDecoder::decoder_status ElfFile::parse_elf(const char* filepath) { |
| assert(filepath, "null file path"); |
| |
| _file = fopen(filepath, "r"); |
| if (_file != NULL) { |
| return load_tables(); |
| } else { |
| return NullDecoder::file_not_found; |
| } |
| } |
| |
| //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]); |
| } |
| |
| NullDecoder::decoder_status ElfFile::load_tables() { |
| assert(_file, "file not open"); |
| assert(!NullDecoder::is_error(_status), "already in error"); |
| |
| FileReader freader(fd()); |
| // read elf file header |
| if (!freader.read(&_elfHdr, sizeof(_elfHdr))) { |
| return NullDecoder::file_invalid; |
| } |
| |
| // Check signature |
| if (!is_elf_file(_elfHdr)) { |
| return NullDecoder::file_invalid; |
| } |
| |
| // walk elf file's section headers, and load string tables |
| Elf_Shdr shdr; |
| if (!freader.set_position(_elfHdr.e_shoff)) { |
| return NullDecoder::file_invalid; |
| } |
| |
| for (int index = 0; index < _elfHdr.e_shnum; index ++) { |
| if (!freader.read(&shdr, sizeof(shdr))) { |
| return NullDecoder::file_invalid; |
| } |
| |
| if (shdr.sh_type == SHT_STRTAB) { |
| // string tables |
| ElfStringTable* table = new (std::nothrow) ElfStringTable(fd(), shdr, index); |
| if (table == NULL) { |
| return NullDecoder::out_of_memory; |
| } |
| if (index == _elfHdr.e_shstrndx) { |
| assert(_shdr_string_table == NULL, "Only set once"); |
| _shdr_string_table = table; |
| } else { |
| add_string_table(table); |
| } |
| } else if (shdr.sh_type == SHT_SYMTAB || shdr.sh_type == SHT_DYNSYM) { |
| // symbol tables |
| ElfSymbolTable* table = new (std::nothrow) ElfSymbolTable(fd(), shdr); |
| if (table == NULL) { |
| return NullDecoder::out_of_memory; |
| } |
| add_symbol_table(table); |
| } |
| } |
| #if defined(PPC64) && !defined(ABI_ELFv2) |
| // Now read the .opd section wich contains the PPC64 function descriptor table. |
| // The .opd section is only available on PPC64 (see for example: |
| // http://refspecs.linuxfoundation.org/LSB_3.1.1/LSB-Core-PPC64/LSB-Core-PPC64/specialsections.html) |
| // so this code should do no harm on other platforms but because of performance reasons we only |
| // execute it on PPC64 platforms. |
| // Notice that we can only find the .opd section after we have successfully read in the string |
| // tables in the previous loop, because we need to query the name of each section which is |
| // contained in one of the string tables (i.e. the one with the index m_elfHdr.e_shstrndx). |
| |
| // Reset the file pointer |
| int sect_index = section_by_name(".opd", shdr); |
| |
| if (sect_index == -1) { |
| return NullDecoder::file_invalid; |
| } |
| |
| _funcDesc_table = new (std::nothrow) ElfFuncDescTable(_file, shdr, sect_index); |
| if (_funcDesc_table == NULL) { |
| return NullDecoder::out_of_memory; |
| } |
| #endif |
| return NullDecoder::no_error; |
| } |
| |
| int ElfFile::section_by_name(const char* name, Elf_Shdr& hdr) { |
| assert(name != NULL, "No section name"); |
| size_t len = strlen(name) + 1; |
| ResourceMark rm; |
| char* buf = NEW_RESOURCE_ARRAY(char, len); |
| if (buf == NULL) { |
| return -1; |
| } |
| |
| assert(_shdr_string_table != NULL, "Section header string table should be loaded"); |
| ElfStringTable* const table = _shdr_string_table; |
| MarkedFileReader mfd(fd()); |
| if (!mfd.has_mark() || !mfd.set_position(_elfHdr.e_shoff)) return -1; |
| |
| int sect_index = -1; |
| for (int index = 0; index < _elfHdr.e_shnum; index ++) { |
| if (!mfd.read((void*)&hdr, sizeof(hdr))) { |
| break; |
| } |
| if (table->string_at(hdr.sh_name, buf, len)) { |
| if (strncmp(buf, name, len) == 0) { |
| sect_index = index; |
| break; |
| } |
| } |
| } |
| return sect_index; |
| } |
| |
| bool ElfFile::decode(address addr, char* buf, int buflen, int* offset) { |
| // something already went wrong, just give up |
| if (NullDecoder::is_error(_status)) { |
| return false; |
| } |
| |
| int string_table_index; |
| int pos_in_string_table; |
| int off = INT_MAX; |
| bool found_symbol = false; |
| ElfSymbolTable* symbol_table = _symbol_tables; |
| |
| while (symbol_table != NULL) { |
| if (symbol_table->lookup(addr, &string_table_index, &pos_in_string_table, &off, _funcDesc_table)) { |
| found_symbol = true; |
| break; |
| } |
| symbol_table = symbol_table->next(); |
| } |
| if (!found_symbol) { |
| return false; |
| } |
| |
| ElfStringTable* string_table = get_string_table(string_table_index); |
| |
| if (string_table == NULL) { |
| _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 (_symbol_tables == NULL) { |
| _symbol_tables = table; |
| } else { |
| table->set_next(_symbol_tables); |
| _symbol_tables = table; |
| } |
| } |
| |
| void ElfFile::add_string_table(ElfStringTable* table) { |
| if (_string_tables == NULL) { |
| _string_tables = table; |
| } else { |
| table->set_next(_string_tables); |
| _string_tables = table; |
| } |
| } |
| |
| ElfStringTable* ElfFile::get_string_table(int index) { |
| ElfStringTable* p = _string_tables; |
| while (p != NULL) { |
| if (p->index() == index) return p; |
| p = p->next(); |
| } |
| return NULL; |
| } |
| |
| #endif // !_WINDOWS && !__APPLE__ |