pidfd_getfd

This crate provides a direct binding to the pidfd_getfd syscall along with a slightly more convenient wrapper, get_file_from_pidfd. This also contains an extension trait for pidfd::PidFd and std's PidFd (currently only available on nightly rustc) which provides access to get_file_from_pidfd via PidFdExt::get_file().

Note that pidfds are currently only supported on Linux 5.6 or later, thus this crate will only work on Linux. If any other platform gains support for pidfds, please let me know through an issue or pull request!

Please note that this crate has not been thoroughly tested. Viewer discretion is advised.

Example

use pidfd_getfd::{get_file_from_pidfd, GetFdFlags};
use std::{
    io::{self, Read},
    os::unix::prelude::RawFd,
};

let pidfd: RawFd = /* ... */;
let target_fd: RawFd = /* ... */;
let mut file = get_file_from_pidfd(pidfd, target_fd, GetFdFlags::empty())?;
let mut buf = Vec::new();
file.read_to_end(&mut buf)?;
println!("{:#?}", buf);
Ok(())

Using pidfd:

use pidfd::PidFd;
use pidfd_getfd::{GetFdFlags, PidFdExt};
use std::process::Command;

let child = Command::new("/usr/bin/foo").spawn().expect("failed to run `foo`");
let pidfd = PidFd::from_std_checked(&child)?;
let file_from_child = pidfd.get_file(1, GetFdFlags::empty())?;

Using nightly rustc:

#![feature(linux_pidfd)]

use pidfd_getfd::{GetFdFlags, PidFdExt};
use std::{
    os::linux::process::{ChildExt, CommandExt},
    process::Command,
};

let child = Command::new("/usr/bin/foo")
    .create_pidfd(true)
    .spawn()
    .expect("failed to run `foo`");

let file_from_child = child.pidfd()?.get_file(1, GetFdFlags::empty())?;