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Merge pull request #55 from birth-software/emit-ph-properly

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Emit program headers properly
This commit is contained in:
David 2024-09-17 18:23:52 -06:00 committed by GitHub
commit d1f61b5209
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GPG Key ID: B5690EEEBB952194
1 changed files with 285 additions and 126 deletions
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411
bootstrap/main.c
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@ -386,6 +386,7 @@ STRUCT(ElfProgramHeader)
};
static_assert(sizeof(ElfProgramHeader) == 0x38);
declare_slice(ElfProgramHeader);
decl_vb(ElfProgramHeader);
typedef enum ELFBitCount : u8
{
@ -7048,27 +7049,26 @@ STRUCT(ObjectOptions)
STRUCT(ELFBuilder)
{
VirtualBuffer(u8) file;
VirtualBuffer(ELFSectionHeader) section_headers;
VirtualBuffer(u8) section_string_table;
VirtualBuffer(u8) file;
Slice(ElfProgramHeader) program_headers;
u16 program_header_i;
VirtualBuffer(ElfProgramHeader) program_headers;
SymbolTable static_st;
SymbolTable dynamic_st;
};
fn void elf_ph_init(ELFBuilder* restrict builder)
{
builder->program_headers.length = 6;
auto program_header_size = sizeof(ElfProgramHeader) * builder->program_headers.length;
builder->program_headers.pointer = (ElfProgramHeader*)vb_add(&builder->file, program_header_size);
builder->program_header_i = 0;
}
fn void elf_ph_end(ELFBuilder* restrict builder)
{
assert(builder->program_header_i == builder->program_headers.length);
}
// fn void elf_ph_init(ELFBuilder* restrict builder)
// {
// builder->program_headers.length = 6;
// auto program_header_size = sizeof(ElfProgramHeader) * builder->program_headers.length;
// builder->program_headers.pointer = (ElfProgramHeader*)vb_add(&builder->file, program_header_size);
// builder->program_header_i = 0;
// }
//
// fn void elf_ph_end(ELFBuilder* restrict builder)
// {
// assert(builder->program_header_i == builder->program_headers.length);
// }
STRUCT(ELFSectionCreate)
{
@ -7091,13 +7091,13 @@ fn void vb_align(VirtualBuffer(u8)* buffer, u64 alignment)
memset(pointer, 0, count);
}
fn void elf_add_program_header_raw(ELFBuilder* restrict builder, ElfProgramHeader ph)
{
assert(builder->program_header_i < builder->program_headers.length);
auto* program_header = &builder->program_headers.pointer[builder->program_header_i];
*program_header = ph;
builder->program_header_i += 1;
}
// fn void elf_add_program_header_raw(ELFBuilder* restrict builder, ElfProgramHeader ph)
// {
// assert(builder->program_header_i < builder->program_headers.length);
// auto* program_header = &builder->program_headers.pointer[builder->program_header_i];
// *program_header = ph;
// builder->program_header_i += 1;
// }
fn u64 elf_add_section_no_copy_raw(ELFBuilder* restrict builder, ELFSectionCreate create)
{
@ -7160,21 +7160,21 @@ STRUCT(ELFSegmentCreate)
u64 offset;
};
fn void elf_add_program_segment_no_copy_raw(ELFBuilder* restrict builder, ELFSegmentCreate create)
{
assert((create.offset & (create.alignment - 1)) == 0);
elf_add_program_header_raw(builder, (ElfProgramHeader){
.type = create.type,
.flags = create.flags,
.offset = create.offset,
.virtual_address = create.offset,
.physical_address = create.offset,
.file_size = create.size,
.memory_size = create.size,
.alignment = create.alignment,
});
}
// fn void elf_add_program_segment_no_copy_raw(ELFBuilder* restrict builder, ELFSegmentCreate create)
// {
// assert((create.offset & (create.alignment - 1)) == 0);
//
// elf_add_program_header_raw(builder, (ElfProgramHeader){
// .type = create.type,
// .flags = create.flags,
// .offset = create.offset,
// .virtual_address = create.offset,
// .physical_address = create.offset,
// .file_size = create.size,
// .memory_size = create.size,
// .alignment = create.alignment,
// });
// }
fn void elf_fill_program_header(ElfProgramHeader* restrict ph, ELFSegmentCreate create)
{
@ -7199,25 +7199,25 @@ STRUCT(ELFSegmentSectionCreate)
String content;
};
fn u64 elf_add_both_segment_and_section(ELFBuilder* restrict builder, ELFSegmentSectionCreate create)
{
assert(create.section.size == 0);
assert(create.content.length > 0);
create.section.size = create.content.length;
vb_align(&builder->file, create.section.alignment);
auto offset = elf_add_section_no_copy_raw(builder, create.section);
ELFSegmentCreate segment = {
.type = create.ph_type,
.flags = create.ph_flags,
.size = create.section.size,
.alignment = create.section.alignment,
.offset = offset,
};
elf_add_program_segment_no_copy_raw(builder, segment);
memcpy(vb_add(&builder->file, create.content.length), create.content.pointer, create.content.length);
return offset;
}
// fn u64 elf_add_both_segment_and_section(ELFBuilder* restrict builder, ELFSegmentSectionCreate create)
// {
// assert(create.section.size == 0);
// assert(create.content.length > 0);
// create.section.size = create.content.length;
// vb_align(&builder->file, create.section.alignment);
// auto offset = elf_add_section_no_copy_raw(builder, create.section);
// ELFSegmentCreate segment = {
// .type = create.ph_type,
// .flags = create.ph_flags,
// .size = create.section.size,
// .alignment = create.section.alignment,
// .offset = offset,
// };
// elf_add_program_segment_no_copy_raw(builder, segment);
// memcpy(vb_add(&builder->file, create.content.length), create.content.pointer, create.content.length);
//
// return offset;
// }
typedef enum SymbolKind : u8
{
@ -7595,66 +7595,82 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
auto shstrtab_section_name = elf_get_section_name(builder, strlit(".shstrtab"));
auto* elf_header = vb_add_struct(&builder->file, ELFHeader);
// TODO: precompute properly how many program segments we are going to need
u16 program_header_count = 13;
// u64 section_header_offset = 13904;
auto* program_headers = vb_add(&builder->file, sizeof(ElfProgramHeader) * program_header_count);
ElfProgramHeader expected_program_headers[] = {
{ .type = PT_PHDR, .flags = {.executable = 0, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 64, .virtual_address = 64, .physical_address = 64, .file_size = 728, .memory_size = 728, .alignment = 8},
{ .type = PT_INTERP, .flags = {.executable = 0, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 792, .virtual_address = 792, .physical_address = 792, .file_size = 28, .memory_size = 28, .alignment = 1},
{ .type = PT_LOAD, .flags = {.executable = 0, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 0, .virtual_address = 0, .physical_address = 0, .file_size = 1496, .memory_size = 1496, .alignment = 4096},
{ .type = PT_LOAD, .flags = { .executable = 1, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 4096, .virtual_address = 4096, .physical_address = 4096, .file_size = 301, .memory_size = 301, .alignment = 4096},
{ .type = PT_LOAD, .flags = {.executable = 0, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 8192, .virtual_address = 8192, .physical_address = 8192, .file_size = 104, .memory_size = 104, .alignment = 4096},
{ .type = PT_LOAD, .flags = {.executable = 0, .writeable = 1, .readable = 1, .reserved = 0}, .offset = 11792, .virtual_address = 15888, .physical_address = 15888, .file_size = 512, .memory_size = 520, .alignment = 4096},
{ .type = PT_DYNAMIC, .flags = {.executable = 0, .writeable = 1, .readable = 1, .reserved = 0}, .offset = 11808, .virtual_address = 15904, .physical_address = 15904, .file_size = 416, .memory_size = 416, .alignment = 8},
{ .type = PT_NOTE, .flags = {.executable = 0, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 824, .virtual_address = 824, .physical_address = 824, .file_size = 32, .memory_size = 32, .alignment = 8},
{ .type = PT_NOTE, .flags = {.executable = 0, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 856, .virtual_address = 856, .physical_address = 856, .file_size = 68, .memory_size = 68, .alignment = 4},
{ .type = PT_GNU_PROPERTY, .flags = {.executable = 0, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 824, .virtual_address = 824, .physical_address = 824, .file_size = 32, .memory_size = 32, .alignment = 8},
{ .type = PT_GNU_EH_FRAME, .flags = {.executable = 0, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 8196, .virtual_address = 8196, .physical_address = 8196, .file_size = 28, .memory_size = 28, .alignment = 4},
{ .type = PT_GNU_STACK, .flags = {.executable = 0, .writeable = 1, .readable = 1, .reserved = 0}, .offset = 0, .virtual_address = 0, .physical_address = 0, .file_size = 0, .memory_size = 0, .alignment = 16},
{ .type = PT_GNU_RELRO, .flags = { .executable = 0, .writeable = 0, .readable = 1, .reserved = 0}, .offset = 11792, .virtual_address = 15888, .physical_address = 15888, .file_size = 496, .memory_size = 496, .alignment = 1}
};
{
// Add program header segment
auto offset = sizeof(ELFHeader);
auto size = sizeof(ElfProgramHeader) * program_header_count;
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_PHDR,
.flags = { .readable = 1 },
.offset = offset,
.virtual_address = offset,
.physical_address = offset,
.file_size = size,
.memory_size = size,
.alignment = alignof(ElfProgramHeader),
};
}
auto* program_headers = vb_add_struct(&builder->file, typeof(expected_program_headers));
memcpy(program_headers, expected_program_headers, sizeof(expected_program_headers));
// auto* ptr = (u8*)(program_headers + array_length(expected_program_headers));
{
// .interp
// Section #1
u64 interp_alignment = 1;
vb_align(&builder->file, interp_alignment);
auto interp = strlit("/lib64/ld-linux-x86-64.so.2");
auto* interp_section_header = vb_add(&builder->section_headers, 1);
auto interp_size = interp.length + 1;
auto interp_offset = builder->file.length;
memcpy(vb_add(&builder->file, interp_size), interp.pointer, interp_size);
auto* section_header = vb_add(&builder->section_headers, 1);
auto interp_section_name = elf_get_section_name(builder, strlit(".interp"));
*interp_section_header = (ELFSectionHeader)
u64 alignment = 1;
vb_align(&builder->file, alignment);
auto offset = builder->file.length;
auto content = strlit("/lib64/ld-linux-x86-64.so.2");
auto size = content.length + 1;
memcpy(vb_add(&builder->file, size), content.pointer, size);
*section_header = (ELFSectionHeader)
{
.name_offset = interp_section_name,
.type = ELF_SECTION_PROGRAM,
.flags = {
.alloc = 1,
},
.address = interp_offset,
.offset = interp_offset,
.size = interp_size,
.address = offset,
.offset = offset,
.size = size,
.link = 0,
.info = 0,
.alignment = 1,
.alignment = alignment,
.entry_size = 0,
};
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_INTERP,
.flags = {.readable = 1,},
.offset = offset,
.virtual_address = offset,
.physical_address = offset,
.file_size = size,
.memory_size = size,
.alignment = alignment,
};
}
u32 gnu_property_offset = 0;
u32 gnu_property_size = 0;
u32 gnu_property_alignment = 0;
{
// .note.gnu.property
// Section #2
auto* gnu_property_section_header = vb_add(&builder->section_headers, 1);
u64 alignment = 8;
gnu_property_alignment = alignment;
vb_align(&builder->file, alignment);
auto offset = builder->file.length;
gnu_property_offset = offset;
auto gnu_property_section_name = elf_get_section_name(builder, strlit(".note.gnu.property"));
auto gnu_string = strlit("GNU");
@ -7672,7 +7688,7 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
memcpy(vb_add(&builder->file, sizeof(gnu_property_blob)), gnu_property_blob, sizeof(gnu_property_blob));
auto gnu_property_size = builder->file.length - offset;
gnu_property_size = builder->file.length - offset;
*gnu_property_section_header = (ELFSectionHeader)
{
@ -7691,14 +7707,18 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
u32 gnu_build_id_offset = 0;
u32 gnu_build_id_alignment = 0;
{
// .note.gnu.build-id
// Section #3
auto* section_header = vb_add(&builder->section_headers, 1);
u64 alignment = 4;
gnu_build_id_alignment = alignment;
auto name = elf_get_section_name(builder, strlit(".note.gnu.build-id"));
vb_align(&builder->file, alignment);
auto offset = builder->file.length;
gnu_build_id_offset = offset;
auto gnu_string = strlit("GNU");
auto gnu_string_size = gnu_string.length + 1;
@ -7781,6 +7801,8 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
auto gnu_build_id_abi_note_size = builder->file.length - gnu_build_id_offset;
u16 preliminar_section_count = builder->section_headers.length + 1;
auto dynamic_symbol_table_index = preliminar_section_count;
auto dynamic_string_table_index = dynamic_symbol_table_index + 1;
@ -8082,8 +8104,28 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
// Add read-only program segment
{
auto offset = builder->file.length;
assert(offset == 1496);
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader)
{
.type = PT_LOAD,
.flags = {.readable = 1},
.offset = 0,
.virtual_address = 0,
.physical_address = 0,
.file_size = offset,
.memory_size = offset,
.alignment = 0x1000,
};
}
vb_align(&builder->file, 0x1000);
auto code_offset = builder->file.length;
{
// .init
auto* section_header = vb_add(&builder->section_headers, 1);
@ -8205,8 +8247,27 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
// Add code segment (read, execute)
{
auto current_offset = builder->file.length;
auto length = current_offset - code_offset;
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader)
{
.type = PT_LOAD,
.flags = { .executable = 1, .readable = 1},
.offset = code_offset,
.virtual_address = code_offset,
.physical_address = code_offset,
.file_size = length,
.memory_size = length,
.alignment = 0x1000,
};
}
vb_align(&builder->file, 0x1000);
auto read_only_offset = builder->file.length;
{
// .rodata
auto* section_header = vb_add(&builder->section_headers, 1);
@ -8239,13 +8300,18 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
u32 eh_frame_offset = 0;
u32 eh_frame_size = 0;
u32 eh_frame_alignment = 0;
{
// .eh_frame_hdr
auto* section_header = vb_add(&builder->section_headers, 1);
u64 alignment = 4;
eh_frame_alignment = alignment;
vb_align(&builder->file, alignment);
auto offset = builder->file.length;
eh_frame_offset = offset;
auto name = elf_get_section_name(builder, strlit(".eh_frame_hdr"));
@ -8264,6 +8330,7 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
auto size = sizeof(eh_frame_hdr) + sizeof(entries);
eh_frame_size = size;
auto* dst = vb_add(&builder->file, size);
memcpy(dst, &eh_frame_hdr, sizeof(eh_frame_hdr));
@ -8344,6 +8411,22 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
{
auto current_offset = builder->file.length;
auto size = current_offset - read_only_offset;
// Add ro program header
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_LOAD,
.flags = {.readable = 1},
.offset = read_only_offset,
.virtual_address = read_only_offset,
.physical_address = read_only_offset,
.file_size = size,
.memory_size = size,
.alignment = 0x1000,
};
}
u64 init_array_size = 8;
u64 fini_array_size = 8;
u64 dynamic_size = 416;
@ -8359,6 +8442,9 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
auto virtual_address_offset = 0x1000;
auto* data_program_header = vb_add(&builder->program_headers, 1);
auto data_offset = builder->file.length;
{
// .init_array
auto* section_header = vb_add(&builder->section_headers, 1);
@ -8492,6 +8578,20 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
.alignment = alignment,
.entry_size = sizeof(ElfDynamicEntry),
};
// Add dynamic program header
{
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_DYNAMIC,
.flags = {.writeable = 1, .readable = 1},
.offset = offset,
.virtual_address = virtual_address,
.physical_address = virtual_address,
.file_size = size,
.memory_size = size,
.alignment = alignof(ElfDynamicEntry),
};
}
}
{
@ -8562,6 +8662,77 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
// Add several program headers
{
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_NOTE,
.flags = {.readable = 1},
.offset = gnu_property_offset,
.virtual_address = gnu_property_offset,
.physical_address = gnu_property_offset,
.file_size = gnu_property_size,
.memory_size = gnu_property_size,
.alignment = gnu_property_alignment,
};
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_NOTE,
.flags = {.readable = 1},
.offset = gnu_build_id_offset,
.virtual_address = gnu_build_id_offset,
.physical_address = gnu_build_id_offset,
.file_size = gnu_build_id_abi_note_size,
.memory_size = gnu_build_id_abi_note_size,
.alignment = gnu_build_id_alignment,
};
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_GNU_PROPERTY,
.flags = {.readable = 1},
.offset = gnu_property_offset,
.virtual_address = gnu_property_offset,
.physical_address = gnu_property_offset,
.file_size = gnu_property_size,
.memory_size = gnu_property_size,
.alignment = gnu_property_alignment,
};
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_GNU_EH_FRAME,
.flags = {.readable = 1},
.offset = eh_frame_offset,
.virtual_address = eh_frame_offset,
.physical_address = eh_frame_offset,
.file_size = eh_frame_size,
.memory_size = eh_frame_size,
.alignment = eh_frame_alignment,
};
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_GNU_STACK,
.flags = { .writeable = 1, .readable = 1},
.offset = 0,
.virtual_address = 0,
.physical_address = 0,
.file_size = 0,
.memory_size = 0,
.alignment = 16,
};
auto relro_end = builder->file.length;
auto size = relro_end - data_offset;
auto virtual_address = data_offset + virtual_address_offset;
*vb_add(&builder->program_headers, 1) = (ElfProgramHeader) {
.type = PT_GNU_RELRO,
.flags = { .readable = 1},
.offset = data_offset,
.virtual_address = virtual_address,
.physical_address = virtual_address,
.file_size = size,
.memory_size = size,
.alignment = 1
};
}
vb_align(&builder->file, 0x1000);
{
@ -8596,6 +8767,7 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
auto bss_size = 0;
{
// .bss
auto* section_header = vb_add(&builder->section_headers, 1);
@ -8607,7 +8779,7 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
auto name = elf_get_section_name(builder, strlit(".bss"));
auto size = 8;
bss_size = 8;
*section_header = (ELFSectionHeader) {
.name_offset = name,
@ -8618,7 +8790,7 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
},
.address = virtual_address,
.offset = offset,
.size = size,
.size = bss_size,
.link = 0,
.info = 0,
.alignment = alignment,
@ -8626,6 +8798,23 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
// Fill data program header (writeable, readable)
{
auto current_offset = builder->file.length;
auto file_size = current_offset - data_offset;
auto virtual_address = data_offset + virtual_address_offset;
*data_program_header = (ElfProgramHeader) {
.type = PT_LOAD,
.flags = {.writeable = 1, .readable = 1},
.offset = data_offset,
.virtual_address = virtual_address,
.physical_address = virtual_address,
.file_size = file_size,
.memory_size = file_size + bss_size,
.alignment = 0x1000,
};
}
u64 virtual_address = 0;
{
@ -8778,40 +8967,6 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
};
}
// {
// // .debug_frame
// auto* section_header = vb_add(&builder->section_headers, 1);
// u64 alignment = 8;
//
// vb_align(&builder->file, alignment);
// auto offset = builder->file.length;
//
// auto name = elf_get_section_name(builder, strlit(".debug_frame"));
//
// u8 data[] = {
// 0x14, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x04, 0x00, 0x08, 0x00, 0x01, 0x78, 0x10, 0x0C,
// 0x07, 0x08, 0x90, 0x01, 0x00, 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
// 0x1C, 0x11, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
// };
//
// auto size = sizeof(data);
//
// memcpy(vb_add(&builder->file, size), data, size);
//
// *section_header = (ELFSectionHeader) {
// .name_offset = name,
// .type = ELF_SECTION_PROGRAM,
// .flags = {},
// .address = virtual_address,
// .offset = offset,
// .size = size,
// .link = 0,
// .info = 0,
// .alignment = alignment,
// .entry_size = 0,
// };
// }
{
// .debug_str
auto* section_header = vb_add(&builder->section_headers, 1);
@ -9115,7 +9270,11 @@ may_be_unused fn void write_elf(Thread* thread, const ObjectOptions* const restr
.section_header_string_table_index = section_header_count - 1,
};
assert(builder->program_headers.length == program_header_count);
memcpy(program_headers, builder->program_headers.pointer, sizeof(ElfProgramHeader) * builder->program_headers.length);
// Check if the file matches
// {
// auto s = file_read(thread->arena, strlit("/home/david/minimal/main"));
//