artiq-zynq/firmware/libdyld/src/file.rs

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2020-05-01 07:19:10 +08:00
use core::{mem, ptr, ops::{Deref, Range}};
2020-04-30 04:01:12 +08:00
use super::{
Arch,
elf::*,
};
fn read_unaligned<T: Copy>(data: &[u8], offset: usize) -> Option<T> {
if data.len() < offset + mem::size_of::<T>() {
None
} else {
let ptr = data.as_ptr().wrapping_offset(offset as isize) as *const T;
Some(unsafe { ptr::read_unaligned(ptr) })
}
}
/// ELF file
pub struct File<'a> {
pub ehdr: Elf32_Ehdr,
data: &'a [u8],
}
impl<'a> File<'a> {
pub fn new(data: &'a [u8]) -> Option<Self> {
let ehdr = read_unaligned(data, 0)?;
Some(File { ehdr, data })
}
fn read_unaligned<T: Copy>(&self, offset: usize) -> Option<T> {
read_unaligned(self.data, offset)
}
pub fn arch(&self) -> Option<Arch> {
const IDENT_OPENRISC: [u8; EI_NIDENT] = [
ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3,
ELFCLASS32, ELFDATA2MSB, EV_CURRENT, ELFOSABI_NONE,
/* ABI version */ 0, /* padding */ 0, 0, 0, 0, 0, 0, 0
];
const IDENT_ARM: [u8; EI_NIDENT] = [
ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3,
ELFCLASS32, ELFDATA2LSB, EV_CURRENT, ELFOSABI_NONE,
/* ABI version */ 0, /* padding */ 0, 0, 0, 0, 0, 0, 0
];
match (self.ehdr.e_ident, self.ehdr.e_machine) {
(IDENT_ARM, EM_ARM) => Some(Arch::Arm),
(IDENT_OPENRISC, EM_OPENRISC) => Some(Arch::OpenRisc),
_ => None,
}
}
pub fn program_headers<'b>(&'b self) -> impl Iterator<Item = Option<Elf32_Phdr>> + 'b
{
(0..self.ehdr.e_phnum).map(move |i| {
let phdr_off = self.ehdr.e_phoff as usize + mem::size_of::<Elf32_Phdr>() * i as usize;
self.read_unaligned::<Elf32_Phdr>(phdr_off)
})
}
pub fn dyn_header_vaddr(&self) -> Option<Range<usize>> {
self.program_headers()
.filter_map(|phdr| phdr)
.find(|phdr| phdr.p_type == PT_DYNAMIC)
.map(|phdr| phdr.p_vaddr as usize..(phdr.p_vaddr + phdr.p_filesz) as usize)
}
}
impl Deref for File<'_> {
type Target = [u8];
fn deref(&self) -> &Self::Target {
self.data
}
}