287 lines
8.4 KiB
C++
287 lines
8.4 KiB
C++
/*
|
|
* Copyright (c) 1997, 2013, 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/elfFuncDescTable.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_funcDesc_table = NULL;
|
|
m_next = NULL;
|
|
m_status = NullDecoder::no_error;
|
|
|
|
int len = strlen(filepath) + 1;
|
|
m_filepath = (const char*)os::malloc(len * sizeof(char), mtInternal);
|
|
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;
|
|
}
|
|
if (shdr.sh_type == SHT_STRTAB) {
|
|
// string tables
|
|
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) {
|
|
// symbol tables
|
|
ElfSymbolTable* table = new (std::nothrow) ElfSymbolTable(m_file, shdr);
|
|
if (table == NULL) {
|
|
m_status = NullDecoder::out_of_memory;
|
|
return false;
|
|
}
|
|
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
|
|
if (fseek(m_file, m_elfHdr.e_shoff, SEEK_SET)) {
|
|
m_status = NullDecoder::file_invalid;
|
|
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;
|
|
}
|
|
if (m_elfHdr.e_shstrndx != SHN_UNDEF && shdr.sh_type == SHT_PROGBITS) {
|
|
ElfStringTable* string_table = get_string_table(m_elfHdr.e_shstrndx);
|
|
if (string_table == NULL) {
|
|
m_status = NullDecoder::file_invalid;
|
|
return false;
|
|
}
|
|
char buf[8]; // '8' is enough because we only want to read ".opd"
|
|
if (string_table->string_at(shdr.sh_name, buf, sizeof(buf)) && !strncmp(".opd", buf, 4)) {
|
|
m_funcDesc_table = new (std::nothrow) ElfFuncDescTable(m_file, shdr, index);
|
|
if (m_funcDesc_table == NULL) {
|
|
m_status = NullDecoder::out_of_memory;
|
|
return false;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
}
|
|
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, m_funcDesc_table)) {
|
|
found_symbol = true;
|
|
break;
|
|
}
|
|
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;
|
|
}
|
|
|
|
#ifdef LINUX
|
|
bool ElfFile::specifies_noexecstack(const char* filepath) {
|
|
// Returns true if the elf file is marked NOT to require an executable stack,
|
|
// or if the file could not be opened.
|
|
// Returns false if the elf file requires an executable stack, the stack flag
|
|
// is not set at all, or if the file can not be read.
|
|
if (filepath == NULL) return true;
|
|
|
|
FILE* file = fopen(filepath, "r");
|
|
if (file == NULL) return true;
|
|
|
|
// AARCH64 defaults to noexecstack. All others default to execstack.
|
|
#ifdef AARCH64
|
|
bool result = true;
|
|
#else
|
|
bool result = false;
|
|
#endif
|
|
|
|
// Read file header
|
|
Elf_Ehdr head;
|
|
if (fread(&head, sizeof(Elf_Ehdr), 1, file) == 1 &&
|
|
is_elf_file(head) &&
|
|
fseek(file, head.e_phoff, SEEK_SET) == 0) {
|
|
|
|
// Read program header table
|
|
Elf_Phdr phdr;
|
|
for (int index = 0; index < head.e_phnum; index ++) {
|
|
if (fread((void*)&phdr, sizeof(Elf_Phdr), 1, file) != 1) {
|
|
result = false;
|
|
break;
|
|
}
|
|
if (phdr.p_type == PT_GNU_STACK) {
|
|
result = (phdr.p_flags == (PF_R | PF_W));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
fclose(file);
|
|
return result;
|
|
}
|
|
#endif // LINUX
|
|
|
|
#endif // !_WINDOWS && !__APPLE__
|