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#[repr(C, packed)]
#[derive(Debug, Copy, Clone)]
pub struct ElfIdent {
/// Magic number - 0x7F, then 'ELF' in ASCII
pub magic: [u8; 4],
/// 1 = 32 bit, 2 = 64 bit
pub class: Class,
// 1 = little endian, 2 = big endian
pub data: Endian,
/// ELF header version
pub version: u8,
/// OS ABI - usually 0 for System V
pub OSABI: OSABI,
// This field is used to distinguish among incompatible versions of an ABI.
pub ABIVersion: u8,
/// Unused/padding
pub _unused: [u8; 7],
}
impl std::fmt::Display for ElfIdent {
fn fmt(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
formatter.write_str(" Magic: ");
for b in unsafe {*(std::ptr::addr_of!(self.magic) as *const [u8; 16])} {
formatter.pad(&format!("{:02x?} ", b));
}
formatter.write_str("\n");
formatter.write_fmt(format_args!(" Class: {:?}\n", self.class));
formatter.write_fmt(format_args!(" Data: {}\n", self.data));
formatter.write_fmt(format_args!(" Version: {} ({})\n", self.version, match self.version {
0 => "invalid",
1 => "current",
2_u8..=u8::MAX => todo!(), // need to cover all cases
}));
formatter.write_fmt(format_args!(" OS/ABI: {}\n", self.OSABI));
formatter.write_fmt(format_args!(" ABI Version: {}\n", self.ABIVersion))
}
}
// https://man7.org/linux/man-pages/man5/elf.5.html
// https://wiki.osdev.org/ELF
// https://en.wikipedia.org/wiki/Executable_and_Linkable_Format
#[repr(C)]
#[derive(Debug)]
pub struct ElfHeader {
pub ident: ElfIdent,
/// 1 = relocatable, 2 = executable, 3 = shared, 4 = core
pub r#type: Type,
/// Instruction set - see table below
pub machine: Machine,
/// ELF Version
pub version: u32,
/// Program entry position (virtual)
pub entry: u64,
/// Program header table position (bytes into file)
pub phoff: u64,
/// Section header table position (bytes into file)
pub shoff: u64,
/// This member holds processor-specific flags associated with the file
/// Currently, no flags have been defined.
pub flags: u32,
/// Header size
pub ehsize: u16,
/// Size of an entry in the program header table
pub phentsize: u16,
/// Number of entries in the program header table
pub phnum: u16,
/// Size of an entry in the section header table
pub shentsize: u16,
/// Number of entries in the section header table
pub shnum: u16,
/// Index in section header table with the section names
pub shstrndx: u16,
}
impl std::fmt::Display for ElfHeader {
fn fmt(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
// yes, this is really what they do in readelf.c
formatter.write_fmt(format_args!("{}", self.ident));
formatter.write_fmt(format_args!(" Type: {}\n", self.r#type));
formatter.write_fmt(format_args!(" Machine: {}\n", self.machine));
formatter.write_fmt(format_args!(" Version: {:#02x?}\n", self.version));
formatter.write_fmt(format_args!(" Entry point address: {:#x?}\n", self.entry));
formatter.write_fmt(format_args!(" Start of program headers: {} (bytes into file)\n", self.phoff));
formatter.write_fmt(format_args!(" Start of section headers: {} (bytes into file)\n", self.shoff));
formatter.write_fmt(format_args!(" Flags: {:#x?}\n", self.flags));
formatter.write_fmt(format_args!(" Size of this header: {} (bytes)\n", self.ehsize));
formatter.write_fmt(format_args!(" Size of program headers: {} (bytes)\n", self.phentsize));
formatter.write_fmt(format_args!(" Number of program headers: {}\n", self.phnum));
formatter.write_fmt(format_args!(" Size of section headers: {} (bytes)\n", self.shentsize));
formatter.write_fmt(format_args!(" Number of section headers: {}\n", self.shnum));
formatter.write_fmt(format_args!(" Section header string table index: {}\n", self.shstrndx))
}
}
#[derive(Debug, Copy, Clone)]
#[repr(u16)]
pub enum Type {
None = 0,
Rel = 1,
Exec = 2,
Dyn = 3,
Core = 4,
}
impl std::fmt::Display for Type {
fn fmt(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
match self {
Type::None => formatter.write_str("NONE (None)"),
Type::Rel => formatter.write_str("REL (Relocatable file)"),
Type::Exec => formatter.write_str("EXEC (Executable file)"),
Type::Dyn => formatter.write_str("DYN (Shared object file)"),
Type::Core => formatter.write_str("CORE (Core file)"),
}
}
}
#[derive(Debug, Copy, Clone)]
#[repr(u16)]
pub enum Machine {
// there are many many many more, im just gonna do x86
// https://github.com/bminor/binutils-gdb/blob/master/binutils/readelf.c#L2746
None = 1,
X86_64 = 62,
}
impl std::fmt::Display for Machine {
fn fmt(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
match self {
Machine::None => formatter.write_str("None"),
Machine::X86_64 => formatter.write_str("Advanced Micro Devices X86-64"),
}
}
}
#[derive(Debug, Copy, Clone)]
#[repr(u8)]
pub enum Class {
ELF32 = 1,
ELF64 = 2,
}
#[derive(Debug, Copy, Clone)]
#[repr(u8)]
pub enum OSABI {
None = 0x00,
SystemV = 0x01,
// HPUX = 0x02,
// Solaris = 0x03,
// IRIX = 0x04,
// FreeBSD = 0x05,
// TRU64 = 0x06,
// ARM = 0x07,
Standalone = 0x08,
}
impl std::fmt::Display for OSABI {
fn fmt(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
match self {
OSABI::None => formatter.write_str("UNIX - System V"),
OSABI::SystemV => formatter.write_str("UNIX - System V"),
OSABI::Standalone => formatter.write_str("Standalone"),
}
}
}
#[derive(Debug, Copy, Clone)]
#[repr(u8)]
pub enum Endian {
Little = 1,
Big = 2,
}
impl std::fmt::Display for Endian {
fn fmt(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
match self {
Endian::Little => formatter.write_str("2's complement, little endian"),
Endian::Big => formatter.write_str("1's complement, big endian"),
}
}
}
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