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separated layout generation and saving

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Many example elfs (hello_32, hello_64, asm ...) require that the
first section directly follows the program header table. The
section header is then placed between segments or at the end.

This change prepares the late placement of section header table.
This commit is contained in:
Mario Werner 2014-11-14 13:06:39 +01:00
parent 55c2841e47
commit c743d0bf74
3 changed files with 52 additions and 28 deletions
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72
elfio/elfio.hpp
View File

@ -158,9 +158,12 @@ class elfio
fill_final_attributes();
set_current_file_position();
is_still_good = layout_segments_and_their_sections();
is_still_good = is_still_good && layout_sections_without_segments();
is_still_good = is_still_good && save_header( f );
is_still_good = is_still_good && save_segments_and_their_sections( f );
is_still_good = is_still_good && save_sections_without_segments( f );
is_still_good = is_still_good && save_sections( f );
is_still_good = is_still_good && save_segments( f );
f.close();
@ -440,6 +443,35 @@ class elfio
return header->save( f );
}
//------------------------------------------------------------------------------
bool save_sections( std::ofstream& f )
{
for ( unsigned int i = 0; i < sections_.size(); ++i ) {
section *sec = sections_.at(i);
std::streampos headerPosition =
(std::streamoff)header->get_sections_offset() +
header->get_section_entry_size() * sec->get_index();
sec->save(f,headerPosition,sec->get_offset());
}
return true;
}
//------------------------------------------------------------------------------
bool save_segments( std::ofstream& f )
{
for ( unsigned int i = 0; i < segments_.size(); ++i ) {
segment *seg = segments_.at(i);
std::streampos headerPosition = header->get_segments_offset() +
header->get_segment_entry_size()*seg->get_index();
seg->save( f, headerPosition, seg->get_offset() );
}
return true;
}
//------------------------------------------------------------------------------
void set_current_file_position()
@ -514,27 +546,24 @@ class elfio
//------------------------------------------------------------------------------
bool save_sections_without_segments( std::ofstream& f )
bool layout_sections_without_segments( )
{
for ( unsigned int i = 0; i < sections_.size(); ++i ) {
if ( is_section_without_segment( i ) ) {
Elf_Xword section_align = sections_[i]->get_addr_align();
section *sec = sections_[i];
Elf_Xword section_align = sec->get_addr_align();
if ( section_align > 1 && current_file_pos % section_align != 0 ) {
current_file_pos += section_align -
current_file_pos % section_align;
}
std::streampos headerPosition =
(std::streamoff)header->get_sections_offset() +
header->get_section_entry_size() * sections_[i]->get_index();
if ( 0 != sec->get_index() )
sec->set_offset(current_file_pos);
sections_[i]->save( f,
headerPosition,
(std::streamoff)current_file_pos );
if ( SHT_NOBITS != sections_[i]->get_type() &&
SHT_NULL != sections_[i]->get_type() ) {
current_file_pos += sections_[i]->get_size();
if ( SHT_NOBITS != sec->get_type() &&
SHT_NULL != sec->get_type() ) {
current_file_pos += sec->get_size();
}
}
}
@ -544,7 +573,7 @@ class elfio
//------------------------------------------------------------------------------
bool save_segments_and_their_sections( std::ofstream& f )
bool layout_segments_and_their_sections( )
{
std::vector<segment*> worklist;
std::vector<bool> section_generated(sections.size(),false);
@ -577,9 +606,6 @@ class elfio
Elf_Half index = seg->get_section_index_at( j );
section* sec = sections[ index ];
std::streampos headerPosition =
(std::streamoff)header->get_sections_offset() +
header->get_section_entry_size()*sec->get_index();
Elf_Xword secAlign = 0;
// fix up the alignment
@ -620,19 +646,17 @@ class elfio
sec->set_address( seg->get_virtual_address()
+ current_file_pos - seg_start_pos);
sec->save( f, headerPosition, (std::streamoff)current_file_pos );
if ( 0 != sec->get_index() )
sec->set_offset(current_file_pos);
if ( SHT_NOBITS != sec->get_type() && SHT_NULL != sec->get_type() )
current_file_pos += sec->get_size();
section_generated[index] = true;
}
Elf64_Off segment_header_position = header->get_segments_offset() +
header->get_segment_entry_size()*seg->get_index();
seg->set_file_size( segment_filesize );
seg->set_memory_size( segment_memory );
seg->save( f, (std::streamoff)segment_header_position,
(std::streamoff)seg_start_pos );
seg->set_offset(seg_start_pos);
}
return true;

4
elfio/elfio_section.hpp
View File

@ -53,7 +53,7 @@ class section
virtual void append_data( const std::string& data ) = 0;
protected:
ELFIO_GET_ACCESS_DECL( Elf64_Off, offset );
ELFIO_GET_SET_ACCESS_DECL( Elf64_Off, offset );
ELFIO_SET_ACCESS_DECL( Elf_Half, index );
virtual void load( std::istream& f,
@ -196,7 +196,7 @@ class section_impl : public section
//------------------------------------------------------------------------------
protected:
//------------------------------------------------------------------------------
ELFIO_GET_ACCESS( Elf64_Off, offset, header.sh_offset );
ELFIO_GET_SET_ACCESS( Elf64_Off, offset, header.sh_offset );
//------------------------------------------------------------------------------
void

4
elfio/elfio_segment.hpp
View File

@ -50,7 +50,7 @@ class segment
virtual Elf_Half get_section_index_at( Elf_Half num ) const = 0;
protected:
ELFIO_GET_ACCESS_DECL( Elf64_Off, offset );
ELFIO_GET_SET_ACCESS_DECL( Elf64_Off, offset );
ELFIO_SET_ACCESS_DECL( Elf_Half, index );
virtual const std::vector<Elf_Half>& get_sections() const = 0;
@ -136,7 +136,7 @@ class segment_impl : public segment
//------------------------------------------------------------------------------
protected:
//------------------------------------------------------------------------------
ELFIO_GET_ACCESS( Elf64_Off, offset, ph.p_offset );
ELFIO_GET_SET_ACCESS( Elf64_Off, offset, ph.p_offset );
//------------------------------------------------------------------------------
const std::vector<Elf_Half>& get_sections() const