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use core::fmt::Debug;
use core::mem;
use crate::elf;
use crate::endian;
use crate::pod::Pod;
use crate::read::util;
use crate::read::{self, Bytes, Error, ReadError};
use super::FileHeader;
/// An iterator over the notes in an ELF section or segment.
#[derive(Debug)]
pub struct NoteIterator<'data, Elf>
where
Elf: FileHeader,
{
endian: Elf::Endian,
align: usize,
data: Bytes<'data>,
}
impl<'data, Elf> NoteIterator<'data, Elf>
where
Elf: FileHeader,
{
/// Returns `Err` if `align` is invalid.
pub(super) fn new(
endian: Elf::Endian,
align: Elf::Word,
data: &'data [u8],
) -> read::Result<Self> {
let align = match align.into() {
0u64..=4 => 4,
8 => 8,
_ => return Err(Error("Invalid ELF note alignment")),
};
// TODO: check data alignment?
Ok(NoteIterator {
endian,
align,
data: Bytes(data),
})
}
/// Returns the next note.
pub fn next(&mut self) -> read::Result<Option<Note<'data, Elf>>> {
let mut data = self.data;
if data.is_empty() {
return Ok(None);
}
let header = data
.read_at::<Elf::NoteHeader>(0)
.read_error("ELF note is too short")?;
// The name has no alignment requirement.
let offset = mem::size_of::<Elf::NoteHeader>();
let namesz = header.n_namesz(self.endian) as usize;
let name = data
.read_bytes_at(offset, namesz)
.read_error("Invalid ELF note namesz")?
.0;
// The descriptor must be aligned.
let offset = util::align(offset + namesz, self.align);
let descsz = header.n_descsz(self.endian) as usize;
let desc = data
.read_bytes_at(offset, descsz)
.read_error("Invalid ELF note descsz")?
.0;
// The next note (if any) must be aligned.
let offset = util::align(offset + descsz, self.align);
if data.skip(offset).is_err() {
data = Bytes(&[]);
}
self.data = data;
Ok(Some(Note { header, name, desc }))
}
}
/// A parsed `NoteHeader`.
#[derive(Debug)]
pub struct Note<'data, Elf>
where
Elf: FileHeader,
{
header: &'data Elf::NoteHeader,
name: &'data [u8],
desc: &'data [u8],
}
impl<'data, Elf: FileHeader> Note<'data, Elf> {
/// Return the `n_type` field of the `NoteHeader`.
///
/// The meaning of this field is determined by `name`.
pub fn n_type(&self, endian: Elf::Endian) -> u32 {
self.header.n_type(endian)
}
/// Return the `n_namesz` field of the `NoteHeader`.
pub fn n_namesz(&self, endian: Elf::Endian) -> u32 {
self.header.n_namesz(endian)
}
/// Return the `n_descsz` field of the `NoteHeader`.
pub fn n_descsz(&self, endian: Elf::Endian) -> u32 {
self.header.n_descsz(endian)
}
/// Return the bytes for the name field following the `NoteHeader`,
/// excluding any null terminator.
///
/// This field is usually a string including a null terminator
/// (but it is not required to be).
///
/// The length of this field (including any null terminator) is given by
/// `n_namesz`.
pub fn name(&self) -> &'data [u8] {
if let Some((last, name)) = self.name.split_last() {
if *last == 0 {
return name;
}
}
self.name
}
/// Return the bytes for the desc field following the `NoteHeader`.
///
/// The length of this field is given by `n_descsz`. The meaning
/// of this field is determined by `name` and `n_type`.
pub fn desc(&self) -> &'data [u8] {
self.desc
}
}
/// A trait for generic access to `NoteHeader32` and `NoteHeader64`.
#[allow(missing_docs)]
pub trait NoteHeader: Debug + Pod {
type Endian: endian::Endian;
fn n_namesz(&self, endian: Self::Endian) -> u32;
fn n_descsz(&self, endian: Self::Endian) -> u32;
fn n_type(&self, endian: Self::Endian) -> u32;
}
impl<Endian: endian::Endian> NoteHeader for elf::NoteHeader32<Endian> {
type Endian = Endian;
#[inline]
fn n_namesz(&self, endian: Self::Endian) -> u32 {
self.n_namesz.get(endian)
}
#[inline]
fn n_descsz(&self, endian: Self::Endian) -> u32 {
self.n_descsz.get(endian)
}
#[inline]
fn n_type(&self, endian: Self::Endian) -> u32 {
self.n_type.get(endian)
}
}
impl<Endian: endian::Endian> NoteHeader for elf::NoteHeader64<Endian> {
type Endian = Endian;
#[inline]
fn n_namesz(&self, endian: Self::Endian) -> u32 {
self.n_namesz.get(endian)
}
#[inline]
fn n_descsz(&self, endian: Self::Endian) -> u32 {
self.n_descsz.get(endian)
}
#[inline]
fn n_type(&self, endian: Self::Endian) -> u32 {
self.n_type.get(endian)
}
}
|
