mirror of
https://github.com/serge1/ELFIO.git
synced 2024-12-28 15:15:04 +00:00
rewrote the segment save logic to not only care about alignment
The initial implementation only made sure that all sections and segments are properly aligned. This is enough for simple embedded applications but can not deal with more complex layouts. The new implementation should be more generic given that it respects the virtual addresses of the individual sections. One thing which is currently not supported by this rewrite are segments which contain the program/segment header or even the whole elf header.
This commit is contained in:
Mario Werner
parent
e5592ddfdd
commit
0ece76b5eb
@ -365,22 +365,40 @@ BOOST_AUTO_TEST_CASE( elfio_copy )
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write_exe_i386( false, false, 0 );
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}
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////////////////////////////////////////////////////////////////////////////////
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BOOST_AUTO_TEST_CASE( elf_exe_copy_64 )
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{
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checkExeAreEqual( "../elf_examples/64bitLOAD.elf",
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"../elf_examples/64bitLOAD_copy.elf" );
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// checkExeAreEqual( "../elf_examples/asm_64",
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// "../elf_examples/asm_64_copy" );
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// checkExeAreEqual( "../elf_examples/hello_64",
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// "../elf_examples/hello_64_copy" );
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// checkExeAreEqual( "../elf_examples/main",
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// "../elf_examples/main_copy" );
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}
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////////////////////////////////////////////////////////////////////////////////
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BOOST_AUTO_TEST_CASE( elf_exe_copy_32 )
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{
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//checkExeAreEqual( "../elf_examples/ls",
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//"../elf_examples/ls_copy" );
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//checkExeAreEqual( "../elf_examples/hello_32",
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//"../elf_examples/hello_32_copy" );
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checkExeAreEqual( "../elf_examples/asm",
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"../elf_examples/asm_copy" );
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// checkExeAreEqual( "../elf_examples/asm64",
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// "../elf_examples/asm64_copy" );
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//checkExeAreEqual( "../elf_examples/hello_64",
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//"../elf_examples/hello_64_copy" );
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// checkExeAreEqual( "../elf_examples/test_ppc",
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// "../elf_examples/test_ppc_copy" );
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checkExeAreEqual("../elf_examples/read_write_arm_elf32_input",
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"../elf_examples/read_write_arm_elf32_input_copy");
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// checkExeAreEqual( "../elf_examples/asm",
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// "../elf_examples/asm_copy" );
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checkExeAreEqual( "../elf_examples/arm_v7m_test_debug.elf",
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"../elf_examples/arm_v7m_test_debug_copy.elf" );
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checkExeAreEqual( "../elf_examples/arm_v7m_test_release.elf",
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"../elf_examples/arm_v7m_test_release_copy.elf" );
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// checkExeAreEqual( "../elf_examples/hello_32",
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// "../elf_examples/hello_32_copy" );
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checkExeAreEqual( "../elf_examples/hello_arm",
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"../elf_examples/hello_arm_copy" );
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checkExeAreEqual( "../elf_examples/hello_arm_stripped",
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"../elf_examples/hello_arm_stripped_copy" );
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// checkExeAreEqual( "../elf_examples/ls",
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// "../elf_examples/ls_copy" );
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// checkExeAreEqual( "../elf_examples/main32",
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// "../elf_examples/main32_copy" );
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checkExeAreEqual( "../elf_examples/read_write_arm_elf32_input",
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"../elf_examples/read_write_arm_elf32_input_copy" );
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// checkExeAreEqual( "../elf_examples/test_ppc",
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// "../elf_examples/test_ppc_copy" );
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}
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BIN
elf_examples/arm_v7m_test_debug.elf
Executable file
BIN
elf_examples/arm_v7m_test_debug.elf
Executable file
Binary file not shown.
BIN
elf_examples/arm_v7m_test_release.elf
Executable file
BIN
elf_examples/arm_v7m_test_release.elf
Executable file
Binary file not shown.
@ -554,66 +554,72 @@ class elfio
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// sub sequence of other segments are located at the end
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worklist = get_ordered_segments();
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// calculate the final alignment for all sections
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for ( unsigned int i = 0; i < segments.size(); ++i )
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{
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for ( unsigned int j = 0; j <segments[i]->get_sections_num(); ++j )
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{
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Elf_Half index = segments[i]->get_section_index_at( j );
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section* sec = sections[ index ];
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if (sec->get_addr_align() > section_alignment[index]) {
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section_alignment[index] = sec->get_addr_align();
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}
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if ( segments[i]->get_align() > section_alignment[index] &&
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j == 0 ) {
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section_alignment[index] = segments[i]->get_align();
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}
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}
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}
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for ( unsigned int i = 0; i < worklist.size(); ++i ) {
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Elf_Xword segment_memory = 0;
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Elf_Xword segment_filesize = 0;
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Elf_Xword current_data_pos = 0;
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Elf_Xword seg_start_pos = 0;
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segment* seg = worklist[i];
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// Write segment's data
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for ( unsigned int j = 0; j <worklist[i]->get_sections_num(); ++j ) {
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Elf_Half index = worklist[i]->get_section_index_at( j );
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// new segments (no sections or not generated sections)
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// have to be aligned
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if( !seg->get_sections_num()
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|| ( seg->get_sections_num()
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&& !section_generated[seg->get_section_index_at( 0 )] )) {
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Elf64_Off error = current_file_pos % seg->get_align();
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current_file_pos += ( seg->get_align() - error ) % seg->get_align();
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seg_start_pos = current_file_pos;
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} else {
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seg_start_pos = sections[seg->get_section_index_at( 0 )]->get_offset();
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}
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section* sec = sections[ worklist[i]->get_section_index_at( j )];
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// Write segment's data
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for ( unsigned int j = 0; j < seg->get_sections_num(); ++j ) {
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Elf_Half index = seg->get_section_index_at( j );
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section* sec = sections[ index ];
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std::streampos headerPosition =
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(std::streamoff)header->get_sections_offset() +
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header->get_section_entry_size()*sec->get_index();
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// calculate the required alignment
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// when the has already been generated then no alignment is required
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Elf_Xword secAlign = 0;
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if ( section_alignment[index] > 1 &&
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current_file_pos % section_alignment[index] != 0 &&
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!section_generated[index] ) {
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secAlign = section_alignment[index] -
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current_file_pos % section_alignment[index];
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// fix up the alignment
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if ( j != 0 && sec->is_address_initialized()
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&& SHT_NOBITS != sec->get_type()
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&& SHT_NULL != sec->get_type() ) {
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// align the sections based on the virtual addresses
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// when possible (this is what matters for execution)
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Elf64_Off req_offset = sec->get_address() - seg->get_virtual_address();
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Elf64_Off cur_offset = current_file_pos - seg_start_pos;
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secAlign = req_offset - cur_offset;
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} else if (j != 0) {
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// if no address has been specified then only the section
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// alignment constraint has to be matched
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Elf64_Off error = current_file_pos % sec->get_addr_align();
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secAlign = ( sec->get_addr_align() - error ) % sec->get_addr_align();
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}
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// determine the segment file and memory sizes
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segment_memory += sec->get_size();
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// special case .tbss section (NOBITS) in non TLS segment
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//
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if ( (sec->get_flags() & SHF_ALLOC)
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&& !( (sec->get_flags() & SHF_TLS) && (seg->get_type() != PT_TLS)
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&& ( SHT_NOBITS == sec->get_type())) )
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segment_memory += sec->get_size() + secAlign;
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if ( SHT_NOBITS != sec->get_type() && SHT_NULL != sec->get_type() )
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segment_filesize += sec->get_size();
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segment_filesize += sec->get_size() + secAlign;
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if( section_generated[index] ) {
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current_data_pos = convertor(sec->get_offset());
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// nothing to be done when generating nested segments
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if(section_generated[index]) {
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continue;
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}
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current_file_pos += secAlign;
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if ( j == 0 )
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current_data_pos = current_file_pos;
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// set the section addresses when missing
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if ( !sec->is_address_initialized() )
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sec->set_address( worklist[i]->get_virtual_address() );
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sec->set_address( seg->get_virtual_address()
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+ current_file_pos - seg_start_pos);
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sec->save( f, headerPosition, (std::streamoff)current_file_pos );
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if ( SHT_NOBITS != sec->get_type() && SHT_NULL != sec->get_type() )
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current_file_pos += sec->get_size();
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@ -621,13 +627,12 @@ class elfio
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}
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Elf64_Off segment_header_position = header->get_segments_offset() +
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header->get_segment_entry_size()*worklist[i]->get_index();
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header->get_segment_entry_size()*seg->get_index();
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worklist[i]->set_file_size( segment_filesize );
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worklist[i]->set_memory_size( segment_memory );
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worklist[i]->save( f,
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(std::streamoff)segment_header_position,
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(std::streamoff)current_data_pos );
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seg->set_file_size( segment_filesize );
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seg->set_memory_size( segment_memory );
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seg->save( f, (std::streamoff)segment_header_position,
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(std::streamoff)seg_start_pos );
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}
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return true;
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