start writing executable

1 files changed, 121 insertions, 0 deletions

diff --git a/src/elf.rs b/src/elf.rs
new file mode 100644
index 0000000..aa9b3f5
--- /dev/null
+++ b/src/elf.rs
@@ -0,0 +1,121 @@
+// basic ELF types and constants
+
+use std::{io, mem};
+
+pub const ET_REL: u16 = 1;
+pub const ET_EXEC: u16 = 2;
+
+#[repr(C)]
+pub struct Header32 {
+	pub ident: [u8; 4],
+	pub class: u8,
+	pub data: u8,
+	pub version: u8,
+	pub abi: u8,
+	pub abiversion: u8,
+	pub pad: [u8; 7],
+	pub r#type: u16,
+	pub machine: u16,
+	pub version2: u32,
+	pub entry: u32,
+	pub phoff: u32,
+	pub shoff: u32,
+	pub flags: u32,
+	pub ehsize: u16,
+	pub phentsize: u16,
+	pub phnum: u16,
+	pub shentsize: u16,
+	pub shnum: u16,
+	pub shstrndx: u16,
+}
+
+impl Default for Header32 {
+	fn default() -> Self {
+		Self {
+			ident: [0x7F, b'E', b'L', b'F'],
+			class: 1,
+			data: 1,
+			version: 1,
+			abi: 0,
+			abiversion: 0,
+			pad: [0; 7],
+			r#type: ET_EXEC,
+			machine: 3,
+			version2: 1,
+			entry: 0,
+			phoff: 0,
+			shoff: 0,
+			flags: 0,
+			ehsize: mem::size_of::<Self>() as _,
+			phentsize: mem::size_of::<Phdr32>() as _,
+			phnum: 0,
+			shentsize: mem::size_of::<Shdr32>() as _,
+			shnum: 0,
+			shstrndx: 0,
+		}
+	}
+}
+
+impl Header32 {
+	pub fn section_offset(&self, ndx: u16) -> u64 {
+		ndx as u64 * self.shentsize as u64 + self.shoff as u64
+	}
+
+	pub fn section_seek(&self, ndx: u16) -> io::SeekFrom {
+		io::SeekFrom::Start(self.section_offset(ndx))
+	}
+
+	pub fn to_bytes(self) -> [u8; 0x34] {
+		unsafe { mem::transmute(self) }
+	}
+}
+
+#[repr(C)]
+#[derive(Clone)]
+pub struct Shdr32 {
+	pub name: u32,
+	pub r#type: u32,
+	pub flags: u32,
+	pub addr: u32,
+	pub offset: u32,
+	pub size: u32,
+	pub link: u32,
+	pub info: u32,
+	pub addralign: u32,
+	pub entsize: u32,
+}
+
+pub const PT_LOAD: u32 = 0;
+
+#[repr(C)]
+pub struct Phdr32 {
+	pub r#type: u32,
+	pub offset: u32,
+	pub vaddr: u32,
+	pub paddr: u32,
+	pub filesz: u32,
+	pub memsz: u32,
+	pub flags: u32,
+	pub align: u32,
+}
+
+impl Default for Phdr32 {
+	fn default() -> Self {
+		Self {
+			r#type: PT_LOAD,
+			offset: 0,
+			vaddr: 0,
+			paddr: 0,
+			filesz: 0,
+			memsz: 0,
+			flags: 0,
+			align: 0x1000,
+		}
+	}
+}
+
+impl Phdr32 {
+	pub fn to_bytes(self) -> [u8; 0x20] {
+		unsafe { mem::transmute(self) }
+	}
+}