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aya/aya/src/maps/array/array.rs

112 lines
3.3 KiB
Rust

use std::{
borrow::{Borrow, BorrowMut},
marker::PhantomData,
os::fd::AsFd as _,
};
use crate::{
maps::{check_bounds, check_kv_size, IterableMap, MapData, MapError},
sys::{bpf_map_lookup_elem, bpf_map_update_elem, SyscallError},
Pod,
};
/// A fixed-size array.
///
/// The size of the array is defined on the eBPF side using the `bpf_map_def::max_entries` field.
/// All the entries are zero-initialized when the map is created.
///
/// # Minimum kernel version
///
/// The minimum kernel version required to use this feature is 3.19.
///
/// # Examples
/// ```no_run
/// # let mut bpf = aya::Ebpf::load(&[])?;
/// use aya::maps::Array;
///
/// let mut array = Array::try_from(bpf.map_mut("ARRAY").unwrap())?;
/// array.set(1, 42, 0)?;
/// assert_eq!(array.get(&1, 0)?, 42);
/// # Ok::<(), aya::EbpfError>(())
/// ```
#[doc(alias = "BPF_MAP_TYPE_ARRAY")]
pub struct Array<T, V: Pod> {
pub(crate) inner: T,
_v: PhantomData<V>,
}
impl<T: Borrow<MapData>, V: Pod> Array<T, V> {
pub(crate) fn new(map: T) -> Result<Self, MapError> {
let data = map.borrow();
check_kv_size::<u32, V>(data)?;
Ok(Self {
inner: map,
_v: PhantomData,
})
}
/// Returns the number of elements in the array.
///
/// This corresponds to the value of `bpf_map_def::max_entries` on the eBPF side.
#[expect(clippy::len_without_is_empty)]
pub fn len(&self) -> u32 {
self.inner.borrow().obj.max_entries()
}
/// Returns the value stored at the given index.
///
/// # Errors
///
/// Returns [`MapError::OutOfBounds`] if `index` is out of bounds, [`MapError::SyscallError`]
/// if `bpf_map_lookup_elem` fails.
pub fn get(&self, index: &u32, flags: u64) -> Result<V, MapError> {
let data = self.inner.borrow();
check_bounds(data, *index)?;
let fd = data.fd().as_fd();
let value = bpf_map_lookup_elem(fd, index, flags).map_err(|io_error| SyscallError {
call: "bpf_map_lookup_elem",
io_error,
})?;
value.ok_or(MapError::KeyNotFound)
}
/// An iterator over the elements of the array. The iterator item type is `Result<V,
/// MapError>`.
pub fn iter(&self) -> impl Iterator<Item = Result<V, MapError>> + '_ {
(0..self.len()).map(move |i| self.get(&i, 0))
}
}
impl<T: BorrowMut<MapData>, V: Pod> Array<T, V> {
/// Sets the value of the element at the given index.
///
/// # Errors
///
/// Returns [`MapError::OutOfBounds`] if `index` is out of bounds, [`MapError::SyscallError`]
/// if `bpf_map_update_elem` fails.
pub fn set(&mut self, index: u32, value: impl Borrow<V>, flags: u64) -> Result<(), MapError> {
let data = self.inner.borrow_mut();
check_bounds(data, index)?;
let fd = data.fd().as_fd();
bpf_map_update_elem(fd, Some(&index), value.borrow(), flags).map_err(|io_error| {
SyscallError {
call: "bpf_map_update_elem",
io_error,
}
})?;
Ok(())
}
}
impl<T: Borrow<MapData>, V: Pod> IterableMap<u32, V> for Array<T, V> {
fn map(&self) -> &MapData {
self.inner.borrow()
}
fn get(&self, index: &u32) -> Result<V, MapError> {
self.get(index, 0)
}
}