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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,15 +1,147 @@ | ||
| use std::{io::ErrorKind, task::Poll}; | ||
| use log::{debug, error, warn}; | ||
| use rustix::{ | ||
| fd::{AsFd, OwnedFd}, | ||
| net::{ | ||
| bind, | ||
| netlink::{self, SocketAddrNetlink}, | ||
| recvfrom, socket_with, AddressFamily, RecvFlags, SocketAddrAny, SocketFlags, SocketType, | ||
| }, | ||
| }; | ||
| use std::{io::ErrorKind, os::unix::prelude::BorrowedFd, path::Path, task::Poll}; | ||
|
|
||
| use crate::{hotplug::HotplugEvent, Error}; | ||
|
|
||
| pub(crate) struct LinuxHotplugWatch {} | ||
| use super::{enumeration::probe_device, events::Async, SysfsPath}; | ||
|
|
||
| const UDEV_MAGIC: &[u8; 12] = b"libudev\0\xfe\xed\xca\xfe"; | ||
| const UDEV_MULTICAST_GROUP: u32 = 1 << 1; | ||
|
|
||
| pub(crate) struct LinuxHotplugWatch { | ||
| fd: Async<OwnedFd>, | ||
| } | ||
|
|
||
| impl LinuxHotplugWatch { | ||
| pub(crate) fn new() -> Result<Self, Error> { | ||
| Err(Error::new(ErrorKind::Unsupported, "Not implemented.")) | ||
| let fd = socket_with( | ||
| AddressFamily::NETLINK, | ||
| SocketType::RAW, | ||
| SocketFlags::CLOEXEC, | ||
| Some(netlink::KOBJECT_UEVENT), | ||
| )?; | ||
| bind(&fd, &SocketAddrNetlink::new(0, UDEV_MULTICAST_GROUP))?; | ||
| Ok(LinuxHotplugWatch { | ||
| fd: Async::new(fd)?, | ||
| }) | ||
| } | ||
|
|
||
| pub(crate) fn poll_next(&mut self, cx: &mut std::task::Context<'_>) -> Poll<HotplugEvent> { | ||
| if let Some(event) = try_receive_event(self.fd.inner.as_fd()) { | ||
| return Poll::Ready(event); | ||
| } | ||
|
|
||
| if let Err(e) = self.fd.register(cx.waker()) { | ||
| log::error!("failed to register udev socket with epoll: {e}"); | ||
| } | ||
|
|
||
| Poll::Pending | ||
| } | ||
| } | ||
|
|
||
| fn try_receive_event(fd: BorrowedFd) -> Option<HotplugEvent> { | ||
| let mut buf = [0; 8192]; | ||
|
|
||
| match recvfrom(fd, &mut buf, RecvFlags::DONTWAIT) { | ||
| // udev messages will normally be sent to a multicast group, which only | ||
| // root can send to. Reject unicast messages that may be from anywhere. | ||
| Ok((size, Some(SocketAddrAny::Netlink(nl)))) if nl.groups() == UDEV_MULTICAST_GROUP => { | ||
| parse_packet(&buf[..size]) | ||
| } | ||
| Ok((_, src)) => { | ||
| warn!("udev netlink socket received message from {src:?}"); | ||
| None | ||
| } | ||
| Err(e) if e.kind() == ErrorKind::WouldBlock => None, | ||
| Err(e) => { | ||
| error!("udev netlink socket recvfrom failed with {e}"); | ||
| None | ||
| } | ||
| } | ||
| } | ||
|
|
||
| fn parse_packet(buf: &[u8]) -> Option<HotplugEvent> { | ||
| if buf.len() < 24 { | ||
| error!("packet too short: {buf:x?}"); | ||
| return None; | ||
| } | ||
|
|
||
| if !buf.starts_with(UDEV_MAGIC) { | ||
| error!("packet does not start with expected header: {buf:x?}"); | ||
| return None; | ||
| } | ||
|
|
||
| let properties_off = u32::from_ne_bytes(buf[16..20].try_into().unwrap()) as usize; | ||
| let properties_len = u32::from_ne_bytes(buf[20..24].try_into().unwrap()) as usize; | ||
| let Some(properties_buf) = buf.get(properties_off..properties_off + properties_len) else { | ||
| error!("properties offset={properties_off} length={properties_len} exceeds buffer length {len}", len = buf.len()); | ||
| return None; | ||
| }; | ||
|
|
||
| let mut is_add = None; | ||
| let mut busnum = None; | ||
| let mut devnum = None; | ||
| let mut devpath = None; | ||
|
|
||
| for (k, v) in parse_properties(properties_buf) { | ||
| debug!("uevent property {k} = {v}"); | ||
| match k { | ||
| "SUBSYSTEM" if v != "usb" => return None, | ||
| "DEVTYPE" if v != "usb_device" => return None, | ||
| "ACTION" => { | ||
| is_add = Some(match v { | ||
| "add" => true, | ||
| "remove" => false, | ||
| _ => return None, | ||
| }); | ||
| } | ||
| "BUSNUM" => { | ||
| busnum = v.parse::<u8>().ok(); | ||
| } | ||
| "DEVNUM" => { | ||
| devnum = v.parse::<u8>().ok(); | ||
| } | ||
| "DEVPATH" => { | ||
| devpath = Some(v); | ||
| } | ||
| _ => {} | ||
| } | ||
| } | ||
|
|
||
| let is_add = is_add?; | ||
| let busnum = busnum?; | ||
| let devnum = devnum?; | ||
| let devpath = devpath?; | ||
|
|
||
| if is_add { | ||
| let path = Path::new("/sys/").join(devpath.trim_start_matches('/')); | ||
| match probe_device(SysfsPath(path.clone())) { | ||
| Ok(d) => Some(HotplugEvent::Connected(d)), | ||
| Err(e) => { | ||
| error!("Failed to probe device {path:?}: {e}"); | ||
| None | ||
| } | ||
| } | ||
| } else { | ||
| Some(HotplugEvent::Disconnected(crate::DeviceId( | ||
| super::DeviceId { | ||
| bus: busnum, | ||
| addr: devnum, | ||
| }, | ||
| ))) | ||
| } | ||
| } | ||
|
|
||
| /// Split nul-separated key=value pairs | ||
| fn parse_properties(buf: &[u8]) -> impl Iterator<Item = (&str, &str)> + '_ { | ||
| buf.split(|b| b == &0) | ||
| .filter_map(|entry| std::str::from_utf8(entry).ok()?.split_once('=')) | ||
| } |