libbpf_rs/
iter.rs

1use std::io;
2use std::os::fd::AsFd;
3use std::os::fd::AsRawFd;
4use std::os::fd::FromRawFd;
5use std::os::fd::OwnedFd;
6
7use crate::Error;
8use crate::Link;
9use crate::Result;
10
11/// Represents a bpf iterator for reading kernel data structures. This requires
12/// Linux 5.8.
13///
14/// This implements [`std::io::Read`] for reading bytes from the iterator.
15/// Methods require working with raw bytes. You may find libraries such as
16/// [`plain`](https://crates.io/crates/plain) helpful.
17#[derive(Debug)]
18pub struct Iter {
19    fd: OwnedFd,
20}
21
22impl Iter {
23    /// Create a new `Iter` wrapping the provided `Link`.
24    pub fn new(link: &Link) -> Result<Self> {
25        let link_fd = link.as_fd().as_raw_fd();
26        let fd = unsafe { libbpf_sys::bpf_iter_create(link_fd) };
27        if fd < 0 {
28            return Err(Error::from(io::Error::last_os_error()));
29        }
30        Ok(Self {
31            fd: unsafe { OwnedFd::from_raw_fd(fd) },
32        })
33    }
34}
35
36impl io::Read for Iter {
37    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
38        let bytes_read =
39            unsafe { libc::read(self.fd.as_raw_fd(), buf.as_mut_ptr() as *mut _, buf.len()) };
40        if bytes_read < 0 {
41            return Err(io::Error::last_os_error());
42        }
43        Ok(bytes_read as usize)
44    }
45}
libbpf_rs/iter.rs

libbpf_rs/
iter.rs
