mirror of
https://github.com/vlang/v.git
synced 2023-08-10 21:13:21 +03:00
native: implement elf section types (#15316)
This commit is contained in:
Spydr
GitHub
parent
a35356758c
commit
dab8159b56
@ -13,9 +13,12 @@ const (
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elf_version = 1
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elf_abiversion = 0
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// elf type
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elf_type_none = 0
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elf_type_rel = 1
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elf_type_exec = 2
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elf_type_dyn = 3
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elf_type_core = 4
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elf_amd64 = 0x3e
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elf_arm64 = 0xb7
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@ -28,19 +31,46 @@ const (
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elf_header_size = 0x40
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elf_phentry_size = 0x38
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elf_shentry_size = 0x40
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elf_symtab_size = 0x18
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elf_sh_symtab_entsize = 0x18
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// elf program header type
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elf_pt_null = 0
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elf_pt_load = 1
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elf_pt_dynamic = 2
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elf_pt_interp = 3
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elf_pt_note = 4
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elf_pt_shlib = 5
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elf_pt_phdr = 6
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elf_pt_tls = 7
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// alignment of program headers
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elf_p_align = 0x1000
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// elf section header size
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elf_shentry_size = 0x40
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// elf section type
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elf_sht_null = 0x00
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elf_sht_progbits = 0x01
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elf_sht_symtab = 0x02
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elf_sht_strtab = 0x03
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elf_sht_rela = 0x04
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elf_sht_hash = 0x05
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elf_sht_dynamic = 0x06
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elf_sht_note = 0x07
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elf_sht_nobits = 0x08
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elf_sht_rel = 0x09
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elf_sht_shlib = 0x0a
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elf_sht_dynsym = 0x0b
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// elf symbol tables
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elf_symtab_size = 0x18
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elf_dynamic_size = 0x10
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elf_rela_size = 0x18
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elf_rel_size = 0x10
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elf_sh_symtab_entsize = elf_symtab_size
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elf_sh_symtab_info = 1
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elf_sh_symtab_align = 8
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elf_sht_strtab = 3
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elf_sht_symtab = 2
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elf_pt_load = 1
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elf_p_align = 0x1000
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// elf symbol bining
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elf_stb_local = u8(0)
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elf_stb_global = u8(1)
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@ -53,6 +83,29 @@ const (
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// elf symbol visibility
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elf_stv_default = i8(0)
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// elf relocation types
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elf_r_amd64_none = 0
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elf_r_amd64_64 = 1
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elf_r_amd64_pc32 = 2
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elf_r_amd64_got32 = 3
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elf_r_amd64_plt32 = 4
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elf_r_amd64_copy = 5
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elf_r_amd64_glob_dat = 6
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elf_r_amd64_jump_slot = 7
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elf_r_amd64_relative = 8
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elf_r_amd64_gotpcrel = 9
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elf_r_amd64_32 = 10
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elf_r_amd64_32s = 11
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elf_r_amd64_16 = 12
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elf_r_amd64_pc16 = 13
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elf_r_amd64_8 = 14
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elf_r_amd64_pc8 = 15
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elf_r_amd64_pc64 = 24
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elf_r_amd64_gotoff64 = 25
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elf_r_amd64_gotpc32 = 26
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elf_r_amd64_size32 = 32
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elf_r_amd64_size64 = 33
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)
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const (
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@ -85,7 +138,7 @@ fn (mut p ProgramHeader) set_addr(addr i64) {
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p.paddr = addr
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}
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fn (mut g Gen) gen_program_header64(p ProgramHeader) {
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fn (mut g Gen) gen_program_header(p ProgramHeader) {
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g.write32(p.typ) // p_type
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g.println('; p_type')
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g.write32(p.flags) // p_flags
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@ -130,19 +183,19 @@ mut:
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entsize i64 // Section entry size.
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}
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struct SymbolTable {
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struct SymbolTableSection {
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str_name string // string name (not generated)
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mut:
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name int // Index to name in .strtab.
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info i8 // symbol type and binding attribute.
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other i8 // Symbol visibility.
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shndx i16 // Related section header table index.
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value i64 // value of the associated symbol
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size i64 // Symbol size
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value i64 // value of the associated symbol.
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size i64 // Symbol size.
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}
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fn (mut g Gen) create_symbol_table(str_name string, info u8, bind u8, other i8, value i64, size i64) SymbolTable {
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return SymbolTable{
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fn (mut g Gen) create_symbol_table_section(str_name string, info u8, bind u8, other i8, value i64, size i64) SymbolTableSection {
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return SymbolTableSection{
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str_name: str_name
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info: i8(info | bind << 4)
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other: other
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@ -151,16 +204,127 @@ fn (mut g Gen) create_symbol_table(str_name string, info u8, bind u8, other i8,
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}
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}
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struct StringTable {
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struct StringTableSection {
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mut:
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strings []string
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}
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fn (mut g Gen) create_string_table(strings []string) StringTable {
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return StringTable{strings}
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fn (mut g Gen) create_string_table_section(strings []string) StringTableSection {
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return StringTableSection{strings}
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}
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type SectionData = StringTable | []SymbolTable
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struct ProgBitsSection {
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mut:
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bytes []u8 // Bytes of information defined by the program.
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}
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fn (mut g Gen) create_progbits_section(bytes []u8) ProgBitsSection {
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return ProgBitsSection{bytes}
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}
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struct RelASection {
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mut:
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offset i64 // Location at which to apply the relocation action.
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info i64 // Symbol table index and type of relocation to apply.
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addend i64 // Constant addent for computing the value of the relocation field.
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}
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fn (mut g Gen) create_rela_section(offset i64, sym u32, typ u32, addend i64) RelASection {
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return RelASection{
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offset: offset
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info: i64((u64(sym) << 32) + typ)
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addend: addend
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}
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}
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struct HashSection {
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// TODO
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}
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fn (mut g Gen) create_hash_section() HashSection {
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return HashSection{}
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}
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struct DynamicSection {
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mut:
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tag i64 // Type of the dynamic Section.
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un i64 // Consists of d_val and d_ptr, represents program virtual addresses.
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}
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fn (mut g Gen) create_dynamic_section(tag i64, val i64) DynamicSection {
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return DynamicSection{tag, val}
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}
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struct NoteSection {
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mut:
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namesz int // Length of the name field in bytes.
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descsz int // Length of the descriptor field in bytes.
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typ int // Type of the node
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name []u8 // Name string of the note.
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desc []u8 // Descripition string of the node, must be aligned by 4 bytes
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}
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fn (mut g Gen) create_note_section(typ int, name string, desc string) NoteSection {
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return NoteSection{
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namesz: name.len
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descsz: desc.len
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typ: typ
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name: name.bytes()
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desc: desc.bytes()
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}
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}
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struct NoBitsSection {
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// The NoBits section does not occupy any bytes in the file
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}
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fn (mut g Gen) chreate_nobits_section() NoBitsSection {
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return NoBitsSection{}
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}
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struct RelSection {
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mut:
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offset i64 // Location at which to apply the relocation action.
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info i64 // Symbol table index and type of relocation to apply.
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}
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fn (mut g Gen) create_rel_section(offset i64, sym u32, typ u32) RelSection {
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return RelSection{
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offset: offset
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info: i64((u64(sym) << 32) + typ)
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}
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}
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struct ShLibSection {
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mut:
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data []u8 // Reserved bytes with unspecified semantics
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}
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fn (mut g Gen) create_shlib_section(data []u8) ShLibSection {
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return ShLibSection{data}
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}
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struct DynSymSection {
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mut:
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symbols []SymbolTableSection
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}
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fn (mut g Gen) create_dynsym_section(symbols []SymbolTableSection) DynSymSection {
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return DynSymSection{symbols}
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}
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type SectionData = DynSymSection
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| HashSection
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| NoBitsSection
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| NoteSection
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| ProgBitsSection
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| RelASection
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| RelSection
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| ShLibSection
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| StringTableSection
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| []DynamicSection
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| []SymbolTableSection
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struct Section {
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name string
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@ -196,13 +360,13 @@ fn (mut g Gen) create_shstrtab(mut sections []Section) {
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names[sections.len] = '.shstrtab'
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mut shstrtab := g.create_section(names[sections.len], native.elf_sht_strtab, 0, 0,
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1, 0, g.create_string_table(names))
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1, 0, g.create_string_table_section(names))
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shstrtab.header.name = offset
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sections << shstrtab
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}
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fn (mut g Gen) create_symtab(mut sections []Section, mut table []SymbolTable) {
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fn (mut g Gen) create_symtab(mut sections []Section, mut table []SymbolTableSection) {
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mut names := []string{len: table.len}
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mut offset := 1
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@ -215,7 +379,7 @@ fn (mut g Gen) create_symtab(mut sections []Section, mut table []SymbolTable) {
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offset += entry.str_name.len + 1
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}
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sections << g.create_section('.strtab', native.elf_sht_strtab, 0, 0, 1, 0, g.create_string_table(names))
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sections << g.create_section('.strtab', native.elf_sht_strtab, 0, 0, 1, 0, g.create_string_table_section(names))
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sections << // index of .strtab
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g.create_section('.symtab', native.elf_sht_symtab, sections.len - 1, native.elf_sh_symtab_info,
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@ -231,7 +395,7 @@ fn (mut g Gen) find_section_header(name string, sections []Section) int {
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return 0
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}
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fn (mut g Gen) gen_section_header64(mut sh SectionHeader) {
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fn (mut g Gen) gen_section_header(mut sh SectionHeader) {
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sh_offset := g.pos()
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g.write32(sh.name) // sh_name
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@ -263,11 +427,30 @@ fn (mut g Gen) gen_section_header64(mut sh SectionHeader) {
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fn (mut g Gen) gen_sections(mut sections []Section) {
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for mut section in sections {
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g.gen_section_header64(mut section.header)
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g.gen_section_header(mut section.header)
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g.println('; ^^^ section header (64) "$section.name"')
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}
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}
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fn (mut g Gen) gen_symtab_data(section Section, data []SymbolTableSection) {
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for symbol in data {
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if symbol.str_name == '_start' {
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g.start_symbol_addr = g.pos()
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}
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g.write32(symbol.name)
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g.write8(symbol.info)
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g.write8(symbol.other)
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g.write16(symbol.shndx)
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g.write64(symbol.value)
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g.write64(symbol.size)
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g.println('; SHT_SYMTAB $symbol.str_name')
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}
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size := native.elf_symtab_size * data.len
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g.write64_at(section.header.offset + 32, i64(size))
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}
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fn (mut g Gen) gen_section_data(sections []Section) {
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for section in sections {
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data := section.data
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@ -276,7 +459,7 @@ fn (mut g Gen) gen_section_data(sections []Section) {
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g.write64_at(section.header.offset + 24, i64(g.pos()))
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match data {
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StringTable {
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StringTableSection {
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start := g.pos()
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g.write8(0) // null-prefixed
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@ -290,24 +473,79 @@ fn (mut g Gen) gen_section_data(sections []Section) {
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size := g.pos() - start
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g.write64_at(section.header.offset + 32, i64(size))
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}
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[]SymbolTable {
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for symbol in data {
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if symbol.str_name == '_start' {
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g.start_symbol_addr = g.pos()
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[]SymbolTableSection {
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g.gen_symtab_data(section, data)
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}
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ProgBitsSection {
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start := g.pos()
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g.write32(symbol.name)
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g.write8(symbol.info)
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g.write8(symbol.other)
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g.write16(symbol.shndx)
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g.write64(symbol.value)
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g.write64(symbol.size)
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g.println('; $symbol')
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}
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g.write(data.bytes)
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g.println('; SHT_PROGBITS Section')
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size := native.elf_symtab_size * data.len
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size := g.pos() - start
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g.write64_at(section.header.offset + 32, i64(size))
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}
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RelASection {
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g.write64(data.offset)
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g.write64(data.info)
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g.write64(data.addend)
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g.println('; SHT_RELA ($data.offset, $data.info, $data.addend)')
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size := native.elf_rela_size
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g.write64_at(section.header.offset + 32, i64(size))
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}
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HashSection {
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// TODO
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g.n_error('ELF Section `SHT_HASH` not implemented yet')
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}
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[]DynamicSection {
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for dyn in data {
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g.write64(dyn.tag)
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g.write64(dyn.un)
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g.println('; SHT_DYNAMIC ($dyn.tag, $dyn.un)')
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}
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size := native.elf_dynamic_size * data.len
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g.write64_at(section.header.offset + 32, i64(size))
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}
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NoteSection {
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start := g.pos()
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g.write32(data.namesz)
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g.write32(data.descsz)
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g.write32(data.typ)
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g.write(data.name)
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for _ in 0 .. ((g.pos() % 4) + 1) {
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g.write8(0) // align by 4 bytes + null terminator
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}
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g.write(data.desc)
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g.write8(0)
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size := g.pos() - start
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g.write64_at(section.header.offset + 32, i64(size))
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}
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NoBitsSection {
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// Nothing to do
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}
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RelSection {
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g.write64(data.offset)
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g.write64(data.info)
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g.println('; SHT_REL ($data.offset, $data.info)')
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size := native.elf_rel_size
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g.write64_at(section.header.offset + 32, i64(size))
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}
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ShLibSection {
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g.write(data.data)
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size := data.data.len
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g.write64_at(section.header.offset + 32, i64(size))
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}
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DynSymSection {
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g.gen_symtab_data(section, data.symbols)
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}
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}
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}
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}
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@ -343,21 +581,26 @@ mut:
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pub fn (mut g Gen) generate_elf_header() {
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elf_type := native.elf_type_exec // PIE (use _exec for non-relocatable executables)
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// generate program headers
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mut program_headers := []ProgramHeader{}
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program_headers << g.create_program_header(native.elf_pt_load, 5, native.elf_p_align)
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// generate sections
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mut sections := [
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Section{}, // null section as first section
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]
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mut symbols := [
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SymbolTable{}, // first is null
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g.create_symbol_table('_start', native.elf_stt_notype, native.elf_stb_global,
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native.elf_stv_default, 0, 0),
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SymbolTableSection{}, // first is null
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g.create_symbol_table_section('_start', native.elf_stt_notype, native.elf_stb_global,
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native.elf_stv_default, 0, 0), // _start label points to entry point address
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]
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g.create_symtab(mut sections, mut symbols)
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g.create_symtab(mut sections, mut symbols) // create the .symtab section
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g.create_shstrtab(mut sections) // create the .shstrtab section (this must be the last section!)
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// write elf header
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g.buf << '\x7fELF'.bytes()
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g.println('; elf header (magic)')
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g.println('; \\x7fELF')
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g.buf << native.elf_class64
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g.buf << native.elf_data_le
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g.buf << native.elf_version
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@ -375,20 +618,20 @@ pub fn (mut g Gen) generate_elf_header() {
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e_entry_addr := g.pos()
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g.write64(0) // e_entry (temp value)
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g.write64(native.elf_header_size) // e_phoff
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g.write64(native.elf_header_size + native.elf_phentry_size) // e_shoff
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g.write64(native.elf_header_size + native.elf_phentry_size * program_headers.len) // e_shoff
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g.write32(0) // e_flags
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g.write16(native.elf_header_size)
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g.write16(native.elf_phentry_size)
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g.write16(1) // e_phnum
|
||||
g.write16(program_headers.len) // e_phnum
|
||||
g.write16(native.elf_shentry_size) // e_shentsize
|
||||
// e_shnum := g.buf.len
|
||||
g.write16(sections.len) // e_shnum (number of sections)
|
||||
g.write16(g.find_section_header('.shstrtab', sections)) // e_shstrndx
|
||||
|
||||
// Elf64_Phdr
|
||||
// Main program header
|
||||
phdr := g.create_program_header(native.elf_pt_load, 5, native.elf_p_align)
|
||||
g.gen_program_header64(phdr)
|
||||
// write program headers
|
||||
for header in program_headers {
|
||||
g.gen_program_header(header)
|
||||
}
|
||||
|
||||
// write section headers
|
||||
g.gen_sections(mut sections)
|
||||
@ -403,7 +646,9 @@ pub fn (mut g Gen) generate_elf_header() {
|
||||
|
||||
g.code_start_pos = g.pos()
|
||||
g.debug_pos = int(g.pos())
|
||||
if elf_type == native.elf_type_exec {
|
||||
g.write64_at(e_entry_addr, g.code_start_pos + native.segment_start)
|
||||
}
|
||||
if g.start_symbol_addr > 0 {
|
||||
g.write64_at(g.start_symbol_addr + native.elf_symtab_size - 16, g.code_start_pos +
|
||||
native.segment_start)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user