aya: add aya::maps::Array

pull/1/head
Alessandro Decina 4 years ago
parent c3b902137b
commit 1746bbf5b8

@ -0,0 +1,151 @@
use std::{
convert::TryFrom,
marker::PhantomData,
mem,
ops::{Deref, DerefMut},
};
use crate::{
generated::bpf_map_type::BPF_MAP_TYPE_ARRAY,
maps::{IterableMap, Map, MapError, MapRef, MapRefMut},
sys::{bpf_map_lookup_elem, bpf_map_update_elem},
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.
pub struct Array<T: Deref<Target = Map>, V: Pod> {
inner: T,
_v: PhantomData<V>,
}
impl<T: Deref<Target = Map>, V: Pod> Array<T, V> {
fn new(map: T) -> Result<Array<T, V>, MapError> {
let map_type = map.obj.def.map_type;
if map_type != BPF_MAP_TYPE_ARRAY as u32 {
return Err(MapError::InvalidMapType {
map_type: map_type as u32,
})?;
}
let expected = mem::size_of::<u32>();
let size = map.obj.def.key_size as usize;
if size != expected {
return Err(MapError::InvalidKeySize { size, expected });
}
let expected = mem::size_of::<V>();
let size = map.obj.def.value_size as usize;
if size != expected {
return Err(MapError::InvalidValueSize { size, expected });
}
let _fd = map.fd_or_err()?;
Ok(Array {
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.
pub fn len(&self) -> u32 {
self.inner.obj.def.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> {
self.check_bounds(*index)?;
let fd = self.inner.fd_or_err()?;
let value = bpf_map_lookup_elem(fd, index, flags).map_err(|(code, io_error)| {
MapError::SyscallError {
call: "bpf_map_lookup_elem".to_owned(),
code,
io_error,
}
})?;
value.ok_or(MapError::KeyNotFound)
}
/// An iterator over the elements of the array. The iterator item type is `Result<V,
/// MapError>`.
pub unsafe fn iter<'coll>(&'coll self) -> impl Iterator<Item = Result<V, MapError>> + 'coll {
(0..self.len()).map(move |i| self.get(&i, 0))
}
fn check_bounds(&self, index: u32) -> Result<(), MapError> {
let max_entries = self.inner.obj.def.max_entries;
if index >= self.inner.obj.def.max_entries {
Err(MapError::OutOfBounds { index, max_entries })
} else {
Ok(())
}
}
}
impl<T: Deref<Target = Map> + DerefMut<Target = Map>, 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.
///
/// # Example
/// ```no_run
/// # let bpf = aya::Bpf::load(&[], None)?;
/// use aya::maps::Array;
/// use std::convert::TryFrom;
///
/// let mut array = Array::try_from(bpf.map_mut("ARRAY")?)?;
/// array.set(1, 42, 0)?;
/// assert_eq!(array.get(&1, 0)?, 42);
/// # Ok::<(), aya::BpfError>(())
/// ```
pub fn set(&mut self, index: u32, value: V, flags: u64) -> Result<(), MapError> {
let fd = self.inner.fd_or_err()?;
self.check_bounds(index)?;
bpf_map_update_elem(fd, &index, &value, flags).map_err(|(code, io_error)| {
MapError::SyscallError {
call: "bpf_map_update_elem".to_owned(),
code,
io_error,
}
})?;
Ok(())
}
}
impl<T: Deref<Target = Map>, V: Pod> IterableMap<u32, V> for Array<T, V> {
fn fd(&self) -> Result<RawFd, MapError> {
self.inner.fd_or_err()
}
unsafe fn get(&self, index: &u32) -> Result<V, MapError> {
self.get(index, 0)
}
}
impl<V: Pod> TryFrom<MapRef> for Array<MapRef, V> {
type Error = MapError;
fn try_from(a: MapRef) -> Result<Array<MapRef, V>, MapError> {
Array::new(a)
}
}
impl<V: Pod> TryFrom<MapRefMut> for Array<MapRefMut, V> {
type Error = MapError;
fn try_from(a: MapRefMut) -> Result<Array<MapRefMut, V>, MapError> {
Array::new(a)
}
}

@ -1,4 +1,6 @@
//! Array types. //! Array types.
mod array;
mod program_array; mod program_array;
pub use array::Array;
pub use program_array::ProgramArray; pub use program_array::ProgramArray;

@ -45,7 +45,7 @@ pub mod hash_map;
mod map_lock; mod map_lock;
pub mod perf; pub mod perf;
pub use array::ProgramArray; pub use array::{Array, ProgramArray};
pub use hash_map::{HashMap, PerCpuHashMap}; pub use hash_map::{HashMap, PerCpuHashMap};
pub use map_lock::*; pub use map_lock::*;
pub use perf::PerfEventArray; pub use perf::PerfEventArray;

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