423 lines
12 KiB
C++
423 lines
12 KiB
C++
// elfcpp_file.h -- file access for elfcpp -*- C++ -*-
|
|
|
|
// Copyright 2006, 2007, Free Software Foundation, Inc.
|
|
// Written by Ian Lance Taylor <iant@google.com>.
|
|
|
|
// This file is part of elfcpp.
|
|
|
|
// This program is free software; you can redistribute it and/or
|
|
// modify it under the terms of the GNU Library General Public License
|
|
// as published by the Free Software Foundation; either version 2, or
|
|
// (at your option) any later version.
|
|
|
|
// In addition to the permissions in the GNU Library General Public
|
|
// License, the Free Software Foundation gives you unlimited
|
|
// permission to link the compiled version of this file into
|
|
// combinations with other programs, and to distribute those
|
|
// combinations without any restriction coming from the use of this
|
|
// file. (The Library Public License restrictions do apply in other
|
|
// respects; for example, they cover modification of the file, and
|
|
/// distribution when not linked into a combined executable.)
|
|
|
|
// This program 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
|
|
// Library General Public License for more details.
|
|
|
|
// You should have received a copy of the GNU Library General Public
|
|
// License along with this program; if not, write to the Free Software
|
|
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
|
|
// 02110-1301, USA.
|
|
|
|
// This header file defines the class Elf_file which can be used to
|
|
// read useful data from an ELF file. The functions here are all
|
|
// templates which take a file interface object as a parameter. This
|
|
// type must have a subtype View. This type must support two methods:
|
|
// View view(off_t file_offset, off_t data_size)
|
|
// returns a View for the specified part of the file.
|
|
// void error(const char* printf_format, ...)
|
|
// prints an error message and does not return. The subtype View must
|
|
// support a method
|
|
// const unsigned char* data()
|
|
// which returns a pointer to a buffer containing the requested data.
|
|
// This general interface is used to read data from the file. Objects
|
|
// of type View will never survive longer than the elfcpp function.
|
|
|
|
// Some of these functions must return a reference to part of the
|
|
// file. To use these, the file interface must support a subtype
|
|
// Location:
|
|
// Location(off_t file_offset, off_t data_size)
|
|
// To use this in conjunction with the accessors types Shdr, etc., the
|
|
// file interface should support an overload of view:
|
|
// View view(Location)
|
|
// This permits writing
|
|
// elfcpp::Shdr shdr(file, ef.section_header(n));
|
|
|
|
#ifndef ELFPCP_FILE_H
|
|
#define ELFCPP_FILE_H
|
|
|
|
#include <string>
|
|
#include <cstring>
|
|
|
|
namespace elfcpp
|
|
{
|
|
|
|
// This object is used to read an ELF file.
|
|
// SIZE: The size of file, 32 or 64.
|
|
// BIG_ENDIAN: Whether the file is in big-endian format.
|
|
// FILE: A file reading type as described above.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
class Elf_file
|
|
{
|
|
private:
|
|
typedef Elf_file<size, big_endian, File> This;
|
|
|
|
public:
|
|
static const int ehdr_size = Elf_sizes<size>::ehdr_size;
|
|
static const int phdr_size = Elf_sizes<size>::phdr_size;
|
|
static const int shdr_size = Elf_sizes<size>::shdr_size;
|
|
static const int sym_size = Elf_sizes<size>::sym_size;
|
|
static const int rel_size = Elf_sizes<size>::rel_size;
|
|
static const int rela_size = Elf_sizes<size>::rela_size;
|
|
|
|
typedef Ehdr<size, big_endian> Ef_ehdr;
|
|
typedef Phdr<size, big_endian> Ef_phdr;
|
|
typedef Shdr<size, big_endian> Ef_shdr;
|
|
typedef Sym<size, big_endian> Ef_sym;
|
|
|
|
// Construct an Elf_file given an ELF file header.
|
|
Elf_file(File* file, const Ef_ehdr& ehdr)
|
|
{ this->construct(file, ehdr); }
|
|
|
|
// Construct an ELF file.
|
|
inline
|
|
Elf_file(File* file);
|
|
|
|
// Return the file offset to the section headers.
|
|
off_t
|
|
shoff() const
|
|
{ return this->shoff_; }
|
|
|
|
// Return the number of sections.
|
|
unsigned int
|
|
shnum()
|
|
{
|
|
this->initialize_shnum();
|
|
return this->shnum_;
|
|
}
|
|
|
|
// Return the section index of the section name string table.
|
|
unsigned int
|
|
shstrndx()
|
|
{
|
|
this->initialize_shnum();
|
|
return this->shstrndx_;
|
|
}
|
|
|
|
// Return the location of the header of section SHNDX.
|
|
typename File::Location
|
|
section_header(unsigned int shndx)
|
|
{
|
|
return typename File::Location(this->section_header_offset(shndx),
|
|
shdr_size);
|
|
}
|
|
|
|
// Return the name of section SHNDX.
|
|
std::string
|
|
section_name(unsigned int shndx);
|
|
|
|
// Return the location of the contents of section SHNDX.
|
|
typename File::Location
|
|
section_contents(unsigned int shndx);
|
|
|
|
// Return the size of section SHNDX.
|
|
typename Elf_types<size>::Elf_WXword
|
|
section_size(unsigned int shndx);
|
|
|
|
// Return the flags of section SHNDX.
|
|
typename Elf_types<size>::Elf_WXword
|
|
section_flags(unsigned int shndx);
|
|
|
|
// Return the type of section SHNDX.
|
|
Elf_Word
|
|
section_type(unsigned int shndx);
|
|
|
|
// Return the link field of section SHNDX.
|
|
Elf_Word
|
|
section_link(unsigned int shndx);
|
|
|
|
// Return the info field of section SHNDX.
|
|
Elf_Word
|
|
section_info(unsigned int shndx);
|
|
|
|
// Return the addralign field of section SHNDX.
|
|
typename Elf_types<size>::Elf_WXword
|
|
section_addralign(unsigned int shndx);
|
|
|
|
private:
|
|
// Shared constructor code.
|
|
void
|
|
construct(File* file, const Ef_ehdr& ehdr);
|
|
|
|
// Initialize shnum_ and shstrndx_.
|
|
void
|
|
initialize_shnum();
|
|
|
|
// Return the file offset of the header of section SHNDX.
|
|
off_t
|
|
section_header_offset(unsigned int shndx);
|
|
|
|
// The file we are reading.
|
|
File* file_;
|
|
// The file offset to the section headers.
|
|
off_t shoff_;
|
|
// The number of sections.
|
|
unsigned int shnum_;
|
|
// The section index of the section name string table.
|
|
unsigned int shstrndx_;
|
|
};
|
|
|
|
// Template function definitions.
|
|
|
|
// Construct an Elf_file given an ELF file header.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
void
|
|
Elf_file<size, big_endian, File>::construct(File* file, const Ef_ehdr& ehdr)
|
|
{
|
|
this->file_ = file;
|
|
this->shoff_ = ehdr.get_e_shoff();
|
|
this->shnum_ = ehdr.get_e_shnum();
|
|
this->shstrndx_ = ehdr.get_e_shstrndx();
|
|
if (ehdr.get_e_ehsize() != This::ehdr_size)
|
|
file->error(_("bad e_ehsize (%d != %d)"),
|
|
ehdr.get_e_ehsize(), This::ehdr_size);
|
|
if (ehdr.get_e_shentsize() != This::shdr_size)
|
|
file->error(_("bad e_shentsize (%d != %d)"),
|
|
ehdr.get_e_shentsize(), This::shdr_size);
|
|
}
|
|
|
|
// Construct an ELF file.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
inline
|
|
Elf_file<size, big_endian, File>::Elf_file(File* file)
|
|
{
|
|
typename File::View v(file->view(file_header_offset, This::ehdr_size));
|
|
this->construct(file, Ef_ehdr(v.data()));
|
|
}
|
|
|
|
// Initialize the shnum_ and shstrndx_ fields, handling overflow.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
void
|
|
Elf_file<size, big_endian, File>::initialize_shnum()
|
|
{
|
|
if ((this->shnum_ == 0 || this->shstrndx_ == SHN_XINDEX)
|
|
&& this->shoff_ != 0)
|
|
{
|
|
typename File::View v(this->file_->view(this->shoff_, This::shdr_size));
|
|
Ef_shdr shdr(v.data());
|
|
if (this->shnum_ == 0)
|
|
this->shnum_ = shdr.get_sh_size();
|
|
if (this->shstrndx_ == SHN_XINDEX)
|
|
this->shstrndx_ = shdr.get_sh_link();
|
|
}
|
|
}
|
|
|
|
// Return the file offset of the section header of section SHNDX.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
off_t
|
|
Elf_file<size, big_endian, File>::section_header_offset(unsigned int shndx)
|
|
{
|
|
if (shndx >= this->shnum())
|
|
this->file_->error(_("section_header_offset: bad shndx %u >= %u"),
|
|
shndx, this->shnum());
|
|
return this->shoff_ + This::shdr_size * shndx;
|
|
}
|
|
|
|
// Return the name of section SHNDX.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
std::string
|
|
Elf_file<size, big_endian, File>::section_name(unsigned int shndx)
|
|
{
|
|
File* const file = this->file_;
|
|
|
|
// Get the section name offset.
|
|
unsigned int sh_name;
|
|
{
|
|
typename File::View v(file->view(this->section_header_offset(shndx),
|
|
This::shdr_size));
|
|
Ef_shdr shdr(v.data());
|
|
sh_name = shdr.get_sh_name();
|
|
}
|
|
|
|
// Get the file offset for the section name string table data.
|
|
off_t shstr_off;
|
|
off_t shstr_size;
|
|
{
|
|
const unsigned int shstrndx = this->shstrndx_;
|
|
typename File::View v(file->view(this->section_header_offset(shstrndx),
|
|
This::shdr_size));
|
|
Ef_shdr shstr_shdr(v.data());
|
|
shstr_off = shstr_shdr.get_sh_offset();
|
|
shstr_size = shstr_shdr.get_sh_size();
|
|
}
|
|
|
|
if (sh_name >= shstr_size)
|
|
file->error(_("bad section name offset for section %u: %u"),
|
|
shndx, sh_name);
|
|
|
|
typename File::View v(file->view(shstr_off, shstr_size));
|
|
|
|
const unsigned char* datau = v.data();
|
|
const char* data = reinterpret_cast<const char*>(datau);
|
|
const void* p = ::memchr(data + sh_name, '\0', shstr_size - sh_name);
|
|
if (p == NULL)
|
|
file->error(_("missing null terminator for name of section %u"),
|
|
shndx);
|
|
|
|
size_t len = static_cast<const char*>(p) - (data + sh_name);
|
|
|
|
return std::string(data + sh_name, len);
|
|
}
|
|
|
|
// Return the contents of section SHNDX.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
typename File::Location
|
|
Elf_file<size, big_endian, File>::section_contents(unsigned int shndx)
|
|
{
|
|
File* const file = this->file_;
|
|
|
|
if (shndx >= this->shnum())
|
|
file->error(_("section_contents: bad shndx %u >= %u"),
|
|
shndx, this->shnum());
|
|
|
|
typename File::View v(file->view(this->section_header_offset(shndx),
|
|
This::shdr_size));
|
|
Ef_shdr shdr(v.data());
|
|
return typename File::Location(shdr.get_sh_offset(), shdr.get_sh_size());
|
|
}
|
|
|
|
// Get the size of section SHNDX.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
typename Elf_types<size>::Elf_WXword
|
|
Elf_file<size, big_endian, File>::section_size(unsigned int shndx)
|
|
{
|
|
File* const file = this->file_;
|
|
|
|
if (shndx >= this->shnum())
|
|
file->error(_("section_size: bad shndx %u >= %u"),
|
|
shndx, this->shnum());
|
|
|
|
typename File::View v(file->view(this->section_header_offset(shndx),
|
|
This::shdr_size));
|
|
|
|
Ef_shdr shdr(v.data());
|
|
return shdr.get_sh_size();
|
|
}
|
|
|
|
// Return the section flags of section SHNDX.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
typename Elf_types<size>::Elf_WXword
|
|
Elf_file<size, big_endian, File>::section_flags(unsigned int shndx)
|
|
{
|
|
File* const file = this->file_;
|
|
|
|
if (shndx >= this->shnum())
|
|
file->error(_("section_flags: bad shndx %u >= %u"),
|
|
shndx, this->shnum());
|
|
|
|
typename File::View v(file->view(this->section_header_offset(shndx),
|
|
This::shdr_size));
|
|
|
|
Ef_shdr shdr(v.data());
|
|
return shdr.get_sh_flags();
|
|
}
|
|
|
|
// Return the type of section SHNDX.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
Elf_Word
|
|
Elf_file<size, big_endian, File>::section_type(unsigned int shndx)
|
|
{
|
|
File* const file = this->file_;
|
|
|
|
if (shndx >= this->shnum())
|
|
file->error(_("section_type: bad shndx %u >= %u"),
|
|
shndx, this->shnum());
|
|
|
|
typename File::View v(file->view(this->section_header_offset(shndx),
|
|
This::shdr_size));
|
|
|
|
Ef_shdr shdr(v.data());
|
|
return shdr.get_sh_type();
|
|
}
|
|
|
|
// Return the sh_link field of section SHNDX.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
Elf_Word
|
|
Elf_file<size, big_endian, File>::section_link(unsigned int shndx)
|
|
{
|
|
File* const file = this->file_;
|
|
|
|
if (shndx >= this->shnum())
|
|
file->error(_("section_link: bad shndx %u >= %u"),
|
|
shndx, this->shnum());
|
|
|
|
typename File::View v(file->view(this->section_header_offset(shndx),
|
|
This::shdr_size));
|
|
|
|
Ef_shdr shdr(v.data());
|
|
return shdr.get_sh_link();
|
|
}
|
|
|
|
// Return the sh_info field of section SHNDX.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
Elf_Word
|
|
Elf_file<size, big_endian, File>::section_info(unsigned int shndx)
|
|
{
|
|
File* const file = this->file_;
|
|
|
|
if (shndx >= this->shnum())
|
|
file->error(_("section_info: bad shndx %u >= %u"),
|
|
shndx, this->shnum());
|
|
|
|
typename File::View v(file->view(this->section_header_offset(shndx),
|
|
This::shdr_size));
|
|
|
|
Ef_shdr shdr(v.data());
|
|
return shdr.get_sh_info();
|
|
}
|
|
|
|
// Return the sh_addralign field of section SHNDX.
|
|
|
|
template<int size, bool big_endian, typename File>
|
|
typename Elf_types<size>::Elf_WXword
|
|
Elf_file<size, big_endian, File>::section_addralign(unsigned int shndx)
|
|
{
|
|
File* const file = this->file_;
|
|
|
|
if (shndx >= this->shnum())
|
|
file->error(_("section_addralign: bad shndx %u >= %u"),
|
|
shndx, this->shnum());
|
|
|
|
typename File::View v(file->view(this->section_header_offset(shndx),
|
|
This::shdr_size));
|
|
|
|
Ef_shdr shdr(v.data());
|
|
return shdr.get_sh_addralign();
|
|
}
|
|
|
|
} // End namespace elfcpp.
|
|
|
|
#endif // !defined(ELFCPP_FILE_H)
|