// Copyright 2014 Renato Tegon Forti, Antony Polukhin.
// Copyright 2015 Antony Polukhin.
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt
// or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_DLL_DETAIL_POSIX_ELF_INFO_HPP
#define BOOST_DLL_DETAIL_POSIX_ELF_INFO_HPP
#include <boost/config.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
# pragma once
#endif
#include <cstring>
#include <boost/filesystem/fstream.hpp>
#include <boost/dll/detail/x_info_interface.hpp>
namespace boost { namespace dll { namespace detail {
template <class AddressOffsetT>
struct Elf_Ehdr_template {
unsigned char e_ident[16]; /* Magic number and other info */
boost::uint16_t e_type; /* Object file type */
boost::uint16_t e_machine; /* Architecture */
boost::uint32_t e_version; /* Object file version */
AddressOffsetT e_entry; /* Entry point virtual address */
AddressOffsetT e_phoff; /* Program header table file offset */
AddressOffsetT e_shoff; /* Section header table file offset */
boost::uint32_t e_flags; /* Processor-specific flags */
boost::uint16_t e_ehsize; /* ELF header size in bytes */
boost::uint16_t e_phentsize; /* Program header table entry size */
boost::uint16_t e_phnum; /* Program header table entry count */
boost::uint16_t e_shentsize; /* Section header table entry size */
boost::uint16_t e_shnum; /* Section header table entry count */
boost::uint16_t e_shstrndx; /* Section header string table index */
};
typedef Elf_Ehdr_template<boost::uint32_t> Elf32_Ehdr_;
typedef Elf_Ehdr_template<boost::uint64_t> Elf64_Ehdr_;
template <class AddressOffsetT>
struct Elf_Shdr_template {
boost::uint32_t sh_name; /* Section name (string tbl index) */
boost::uint32_t sh_type; /* Section type */
AddressOffsetT sh_flags; /* Section flags */
AddressOffsetT sh_addr; /* Section virtual addr at execution */
AddressOffsetT sh_offset; /* Section file offset */
AddressOffsetT sh_size; /* Section size in bytes */
boost::uint32_t sh_link; /* Link to another section */
boost::uint32_t sh_info; /* Additional section information */
AddressOffsetT sh_addralign; /* Section alignment */
AddressOffsetT sh_entsize; /* Entry size if section holds table */
};
typedef Elf_Shdr_template<boost::uint32_t> Elf32_Shdr_;
typedef Elf_Shdr_template<boost::uint64_t> Elf64_Shdr_;
template <class AddressOffsetT>
struct Elf_Sym_template;
template <>
struct Elf_Sym_template<boost::uint32_t> {
typedef boost::uint32_t AddressOffsetT;
boost::uint32_t st_name; /* Symbol name (string tbl index) */
AddressOffsetT st_value; /* Symbol value */
AddressOffsetT st_size; /* Symbol size */
unsigned char st_info; /* Symbol type and binding */
unsigned char st_other; /* Symbol visibility */
boost::uint16_t st_shndx; /* Section index */
};
template <>
struct Elf_Sym_template<boost::uint64_t> {
typedef boost::uint64_t AddressOffsetT;
boost::uint32_t st_name; /* Symbol name (string tbl index) */
unsigned char st_info; /* Symbol type and binding */
unsigned char st_other; /* Symbol visibility */
boost::uint16_t st_shndx; /* Section index */
AddressOffsetT st_value; /* Symbol value */
AddressOffsetT st_size; /* Symbol size */
};
typedef Elf_Sym_template<boost::uint32_t> Elf32_Sym_;
typedef Elf_Sym_template<boost::uint64_t> Elf64_Sym_;
template <class AddressOffsetT>
class elf_info: public x_info_interface {
boost::filesystem::ifstream& f_;
typedef boost::dll::detail::Elf_Ehdr_template<AddressOffsetT> header_t;
typedef boost::dll::detail::Elf_Shdr_template<AddressOffsetT> section_t;
typedef boost::dll::detail::Elf_Sym_template<AddressOffsetT> symbol_t;
BOOST_STATIC_CONSTANT(boost::uint32_t, SHT_SYMTAB_ = 2);
BOOST_STATIC_CONSTANT(boost::uint32_t, SHT_STRTAB_ = 3);
BOOST_STATIC_CONSTANT(unsigned char, STB_LOCAL_ = 0); /* Local symbol */
BOOST_STATIC_CONSTANT(unsigned char, STB_GLOBAL_ = 1); /* Global symbol */
BOOST_STATIC_CONSTANT(unsigned char, STB_WEAK_ = 2); /* Weak symbol */
/* Symbol visibility specification encoded in the st_other field. */
BOOST_STATIC_CONSTANT(unsigned char, STV_DEFAULT_ = 0); /* Default symbol visibility rules */
BOOST_STATIC_CONSTANT(unsigned char, STV_INTERNAL_ = 1); /* Processor specific hidden class */
BOOST_STATIC_CONSTANT(unsigned char, STV_HIDDEN_ = 2); /* Sym unavailable in other modules */
BOOST_STATIC_CONSTANT(unsigned char, STV_PROTECTED_ = 3); /* Not preemptible, not exported */
public:
static bool parsing_supported(boost::filesystem::ifstream& f) {
const unsigned char magic_bytes[5] = {
0x7f, 'E', 'L', 'F', sizeof(boost::uint32_t) == sizeof(AddressOffsetT) ? 1 : 2
};
unsigned char ch;
f.seekg(0);
for (std::size_t i = 0; i < sizeof(magic_bytes); ++i) {
f >> ch;
if (ch != magic_bytes[i]) {
return false;
}
}
return true;
}
explicit elf_info(boost::filesystem::ifstream& f) BOOST_NOEXCEPT
: f_(f)
{}
std::vector<std::string> sections() {
std::vector<std::string> ret;
std::vector<char> names;
sections_names_raw(names);
const char* name_begin = &names[0];
const char* const name_end = name_begin + names.size();
ret.reserve(header().e_shnum);
do {
ret.push_back(name_begin);
name_begin += ret.back().size() + 1;
} while (name_begin != name_end);
return ret;
}
private:
template <class T>
inline void read_raw(T& value, std::size_t size = sizeof(T)) const {
f_.read(reinterpret_cast<char*>(&value), size);
}
inline header_t header() {
header_t elf;
f_.seekg(0);
read_raw(elf);
return elf;
}
void sections_names_raw(std::vector<char>& sections) {
const header_t elf = header();
section_t section_names_section;
f_.seekg(elf.e_shoff + elf.e_shstrndx * sizeof(section_t));
read_raw(section_names_section);
sections.resize(static_cast<std::size_t>(section_names_section.sh_size));
f_.seekg(section_names_section.sh_offset);
read_raw(sections[0], static_cast<std::size_t>(section_names_section.sh_size));
}
void symbols_text(std::vector<symbol_t>& symbols, std::vector<char>& text) {
const header_t elf = header();
f_.seekg(elf.e_shoff);
for (std::size_t i = 0; i < elf.e_shnum; ++i) {
section_t section;
read_raw(section);
if (section.sh_type == SHT_SYMTAB_) {
symbols.resize(static_cast<std::size_t>(section.sh_size / sizeof(symbol_t)));
const boost::filesystem::ifstream::pos_type pos = f_.tellg();
f_.seekg(section.sh_offset);
read_raw(symbols[0], static_cast<std::size_t>(section.sh_size - (section.sh_size % sizeof(symbol_t))) );
f_.seekg(pos);
} else if (section.sh_type == SHT_STRTAB_) {
text.resize(static_cast<std::size_t>(section.sh_size));
const boost::filesystem::ifstream::pos_type pos = f_.tellg();
f_.seekg(section.sh_offset);
read_raw(text[0], static_cast<std::size_t>(section.sh_size));
f_.seekg(pos);
}
}
}
static bool is_visible(const symbol_t& sym) BOOST_NOEXCEPT {
// `(sym.st_info >> 4) != STB_LOCAL_ && !!sym.st_size` check also workarounds the
// GCC's issue https://sourceware.org/bugzilla/show_bug.cgi?id=13621
return (sym.st_other & 0x03) == STV_DEFAULT_ && (sym.st_info >> 4) != STB_LOCAL_ && !!sym.st_size;
}
public:
std::vector<std::string> symbols() {
std::vector<std::string> ret;
std::vector<symbol_t> symbols;
std::vector<char> text;
symbols_text(symbols, text);
ret.reserve(symbols.size());
for (std::size_t i = 0; i < symbols.size(); ++i) {
if (is_visible(symbols[i])) {
ret.push_back(&text[0] + symbols[i].st_name);
if (ret.back().empty()) {
ret.pop_back(); // Do not show empty names
}
}
}
return ret;
}
std::vector<std::string> symbols(const char* section_name) {
std::vector<std::string> ret;
std::size_t index = 0;
std::size_t ptrs_in_section_count = 0;
{
std::vector<char> names;
sections_names_raw(names);
const header_t elf = header();
for (; index < elf.e_shnum; ++index) {
section_t section;
f_.seekg(elf.e_shoff + index * sizeof(section_t));
read_raw(section);
if (!std::strcmp(&names[0] + section.sh_name, section_name)) {
if (!section.sh_entsize) {
section.sh_entsize = 1;
}
ptrs_in_section_count = static_cast<std::size_t>(section.sh_size / section.sh_entsize);
break;
}
}
}
std::vector<symbol_t> symbols;
std::vector<char> text;
symbols_text(symbols, text);
if (ptrs_in_section_count < symbols.size()) {
ret.reserve(ptrs_in_section_count);
} else {
ret.reserve(symbols.size());
}
for (std::size_t i = 0; i < symbols.size(); ++i) {
if (symbols[i].st_shndx == index && is_visible(symbols[i])) {
ret.push_back(&text[0] + symbols[i].st_name);
if (ret.back().empty()) {
ret.pop_back(); // Do not show empty names
}
}
}
return ret;
}
};
typedef elf_info<boost::uint32_t> elf_info32;
typedef elf_info<boost::uint64_t> elf_info64;
}}} // namespace boost::dll::detail
#endif // BOOST_DLL_DETAIL_POSIX_ELF_INFO_HPP