| //! [netlink](https://www.man7.org/linux/man-pages/man7/netlink.7.html) `NETLINK_KOBJECT_UEVENT` packet parser |
| //! |
| //! The [uevents](https://www.kernel.org/doc/html/latest/core-api/kobject.html#uevents) are |
| //! triggered by `kobject_uevent` and `kobject_uevent_env` to signal a change in the referred kobject. |
| |
| use std::{ |
| collections::HashMap, |
| io, |
| path::{Path, PathBuf}, |
| str::{from_utf8, FromStr}, |
| }; |
| |
| #[derive(Debug, thiserror::Error)] |
| pub enum Error { |
| #[error("Unexpected action: {0}")] |
| UnexpectedAction(String), |
| #[error("Invalid DEVPATH: {0}")] |
| InvalidDevPath(String), |
| #[error("Unexpected SEQNUM: {0}")] |
| InvalidSeqNum(String), |
| #[error(transparent)] |
| Io(#[from] io::Error), |
| #[error("Path not inside mountpoint")] |
| NotInsideMountpoint, |
| #[error("Packet not UTF-8")] |
| NotUtf8, |
| #[error("action not found")] |
| ActionNotFound, |
| #[error("devpath not found")] |
| DevPathNotFound, |
| #[error("subsystem not found")] |
| SubsystemNotFound, |
| #[error("seq missing")] |
| SeqMissing, |
| } |
| |
| #[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)] |
| /// KObject action types |
| /// |
| /// See kobject_action in include/linux/kobject.h |
| pub enum ActionType { |
| /// A new kobject is added |
| Add, |
| /// A kobject is removed |
| Remove, |
| /// the kobject changed its internal state |
| /// |
| /// the `env` contains kobject-specific information. |
| Change, |
| /// the kobject is reparented as a result of `kobject_move` |
| /// |
| /// the `env` contains `DEVPATH_OLD=<oldpath>`. |
| Move, |
| /// The device is back online after successful `device_offline`. |
| Online, |
| /// The device is ready to be hot-removed. |
| Offline, |
| /// The device is bound to a driver. |
| Bind, |
| /// The device is not bound to its driver anymore. |
| Unbind, |
| } |
| |
| impl FromStr for ActionType { |
| type Err = Error; |
| fn from_str(s: &str) -> Result<Self, Self::Err> { |
| use ActionType::*; |
| match s { |
| "add" => Ok(Add), |
| "remove" => Ok(Remove), |
| "change" => Ok(Change), |
| "move" => Ok(Move), |
| "online" => Ok(Online), |
| "offline" => Ok(Offline), |
| "bind" => Ok(Bind), |
| "unbind" => Ok(Unbind), |
| _ => Err(Error::UnexpectedAction(s.to_owned())), |
| } |
| } |
| } |
| |
| /// Linux kernel userspace event |
| #[derive(Debug, Clone, PartialEq, Eq)] |
| pub struct UEvent { |
| /// Action happening |
| pub action: ActionType, |
| /// Complete Kernel Object path |
| pub devpath: PathBuf, |
| /// SubSystem originating the event |
| pub subsystem: String, |
| /// Arguments |
| pub env: HashMap<String, String>, |
| /// Sequence number |
| pub seq: u64, |
| } |
| |
| #[derive(Debug, Clone, PartialEq, Eq)] |
| struct MaybeUEvent { |
| /// Action happening |
| pub action: Option<ActionType>, |
| /// Complete Kernel Object path |
| pub devpath: Option<PathBuf>, |
| /// SubSystem originating the event |
| pub subsystem: Option<String>, |
| /// Arguments |
| pub env: HashMap<String, String>, |
| /// Sequence number |
| pub seq: Option<u64>, |
| } |
| |
| /// Parse key=value strings as UEvent, some fields may be missing |
| fn parse_uevent_iter<'a>(iter: impl Iterator<Item = &'a str>) -> Result<MaybeUEvent, Error> { |
| let mut action = None; |
| let mut devpath = None; |
| let mut subsystem = None; |
| let mut env = HashMap::new(); |
| let mut seq = None; |
| |
| for f in iter { |
| if let Some((key, value)) = f.split_once('=') { |
| match key { |
| "ACTION" => action = Some(value.parse::<ActionType>()?), |
| "DEVPATH" => { |
| devpath = Some( |
| value |
| .parse::<PathBuf>() |
| .map_err(|_| Error::InvalidDevPath(value.to_owned()))?, |
| ) |
| } |
| "SUBSYSTEM" => subsystem = Some(value.to_string()), |
| "SEQNUM" => { |
| seq = Some( |
| value |
| .parse::<u64>() |
| .map_err(|_| Error::InvalidSeqNum(value.to_owned()))?, |
| ) |
| } |
| _ => {} |
| } |
| let _ = env.insert(key.into(), value.into()); |
| } |
| } |
| |
| Ok(MaybeUEvent { |
| action, |
| devpath, |
| subsystem, |
| env, |
| seq, |
| }) |
| } |
| |
| impl UEvent { |
| /// Parse a sysfs path as an Add UEvent |
| pub fn from_sysfs_path( |
| path: impl AsRef<Path>, |
| mountpoint: impl AsRef<Path>, |
| ) -> Result<UEvent, Error> { |
| let path = path.as_ref(); |
| let uevent = std::fs::read_to_string(path.join("uevent"))?; |
| let subsystem_path = std::fs::read_link(path.join("subsystem"))?; |
| let lines = uevent.lines(); |
| |
| let MaybeUEvent { env, .. } = parse_uevent_iter(lines)?; |
| |
| let action = ActionType::Add; |
| // make it look like a netlink devpath |
| let devpath = Path::new("/").join( |
| path.canonicalize()? |
| .strip_prefix(mountpoint) |
| .map_err(|_| Error::NotInsideMountpoint)?, |
| ); |
| let subsystem = subsystem_path |
| .file_name() |
| .ok_or(Error::SubsystemNotFound)? |
| .to_string_lossy() |
| .to_string(); |
| let seq = 0; |
| |
| Ok(UEvent { |
| action, |
| devpath, |
| subsystem, |
| env, |
| seq, |
| }) |
| } |
| |
| /// Parse a netlink packet as received from the NETLINK_KOBJECT_UEVENT broadcast |
| pub fn from_netlink_packet(pkt: &[u8]) -> Result<UEvent, Error> { |
| let lines = from_utf8(pkt).map_err(|_| Error::NotUtf8)?.split('\0'); |
| let MaybeUEvent { |
| action, |
| devpath, |
| subsystem, |
| env, |
| seq, |
| } = parse_uevent_iter(lines)?; |
| |
| let action = action.ok_or(Error::ActionNotFound)?; |
| let devpath = devpath.ok_or(Error::DevPathNotFound)?; |
| let subsystem = subsystem.ok_or(Error::SubsystemNotFound)?; |
| let seq = seq.ok_or(Error::SeqMissing)?; |
| |
| Ok(UEvent { |
| action, |
| devpath, |
| subsystem, |
| env, |
| seq, |
| }) |
| } |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use super::*; |
| |
| macro_rules! uevent { |
| ( |
| action: $action:expr, |
| devpath: $devpath:expr, |
| subsystem: $subsystem:expr, |
| env: { $($env_name:expr => $env_value:expr),* $(,)? }, |
| seq: $seq:expr |
| ) => { |
| UEvent { |
| action: $action, |
| devpath: PathBuf::from($devpath), |
| subsystem: $subsystem.to_string(), |
| env: IntoIterator::into_iter([ |
| $(($env_name.to_string(), $env_value.to_string())),* |
| ]).collect(), |
| seq: $seq, |
| } |
| }; |
| } |
| |
| #[test] |
| fn add_uevent() { |
| const DATA: &[u8] = b"add@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=add\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SYNTH_UUID=0\0\ |
| MAJOR=4\0\ |
| MINOR=70\0\ |
| DEVNAME=ttyS6\0\ |
| SEQNUM=3469"; |
| assert_eq!( |
| UEvent::from_netlink_packet(DATA).unwrap(), |
| uevent! { |
| action: ActionType::Add, |
| devpath: "/devices/platform/serial8250/tty/ttyS6", |
| subsystem: "tty", |
| env: { |
| "ACTION" => "add", |
| "DEVPATH" => "/devices/platform/serial8250/tty/ttyS6", |
| "SUBSYSTEM" => "tty", |
| "SYNTH_UUID" => "0", |
| "MAJOR" => "4", |
| "MINOR" => "70", |
| "DEVNAME" => "ttyS6", |
| "SEQNUM" => "3469", |
| }, |
| seq: 3469 |
| } |
| ); |
| } |
| |
| #[test] |
| fn remove_uevent() { |
| const DATA: &[u8] = b"remove@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=remove\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SYNTH_UUID=0\0\ |
| MAJOR=4\0\ |
| MINOR=70\0\ |
| DEVNAME=ttyS6\0\ |
| SEQNUM=3471"; |
| assert_eq!( |
| UEvent::from_netlink_packet(DATA).unwrap(), |
| uevent! { |
| action: ActionType::Remove, |
| devpath: "/devices/platform/serial8250/tty/ttyS6", |
| subsystem: "tty", |
| env: { |
| "ACTION" => "remove", |
| "DEVPATH" => "/devices/platform/serial8250/tty/ttyS6", |
| "SUBSYSTEM" => "tty", |
| "SYNTH_UUID" => "0", |
| "MAJOR" => "4", |
| "MINOR" => "70", |
| "DEVNAME" => "ttyS6", |
| "SEQNUM" => "3471", |
| }, |
| seq: 3471 |
| } |
| ); |
| } |
| |
| #[test] |
| fn change_uevent() { |
| const DATA: &[u8] = b"change@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=change\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SYNTH_UUID=0\0\ |
| MAJOR=4\0\ |
| MINOR=70\0\ |
| DEVNAME=ttyS6\0\ |
| SEQNUM=3472"; |
| assert_eq!( |
| UEvent::from_netlink_packet(DATA).unwrap(), |
| uevent! { |
| action: ActionType::Change, |
| devpath: "/devices/platform/serial8250/tty/ttyS6", |
| subsystem: "tty", |
| env: { |
| "ACTION" => "change", |
| "DEVPATH" => "/devices/platform/serial8250/tty/ttyS6", |
| "SUBSYSTEM" => "tty", |
| "SYNTH_UUID" => "0", |
| "MAJOR" => "4", |
| "MINOR" => "70", |
| "DEVNAME" => "ttyS6", |
| "SEQNUM" => "3472", |
| }, |
| seq: 3472 |
| } |
| ); |
| } |
| |
| #[test] |
| fn move_uevent() { |
| const DATA: &[u8] = b"move@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=move\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SYNTH_UUID=0\0\ |
| MAJOR=4\0\ |
| MINOR=70\0\ |
| DEVNAME=ttyS6\0\ |
| SEQNUM=3473"; |
| assert_eq!( |
| UEvent::from_netlink_packet(DATA).unwrap(), |
| uevent! { |
| action: ActionType::Move, |
| devpath: "/devices/platform/serial8250/tty/ttyS6", |
| subsystem: "tty", |
| env: { |
| "ACTION" => "move", |
| "DEVPATH" => "/devices/platform/serial8250/tty/ttyS6", |
| "SUBSYSTEM" => "tty", |
| "SYNTH_UUID" => "0", |
| "MAJOR" => "4", |
| "MINOR" => "70", |
| "DEVNAME" => "ttyS6", |
| "SEQNUM" => "3473", |
| }, |
| seq: 3473 |
| } |
| ); |
| } |
| |
| #[test] |
| fn online_uevent() { |
| const DATA: &[u8] = b"online@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=online\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SYNTH_UUID=0\0\ |
| MAJOR=4\0\ |
| MINOR=70\0\ |
| DEVNAME=ttyS6\0\ |
| SEQNUM=3474"; |
| assert_eq!( |
| UEvent::from_netlink_packet(DATA).unwrap(), |
| uevent! { |
| action: ActionType::Online, |
| devpath: "/devices/platform/serial8250/tty/ttyS6", |
| subsystem: "tty", |
| env: { |
| "ACTION" => "online", |
| "DEVPATH" => "/devices/platform/serial8250/tty/ttyS6", |
| "SUBSYSTEM" => "tty", |
| "SYNTH_UUID" => "0", |
| "MAJOR" => "4", |
| "MINOR" => "70", |
| "DEVNAME" => "ttyS6", |
| "SEQNUM" => "3474", |
| }, |
| seq: 3474 |
| } |
| ); |
| } |
| |
| #[test] |
| fn offline_uevent() { |
| const DATA: &[u8] = b"offline@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=offline\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SYNTH_UUID=0\0\ |
| MAJOR=4\0\ |
| MINOR=70\0\ |
| DEVNAME=ttyS6\0\ |
| SEQNUM=3475"; |
| assert_eq!( |
| UEvent::from_netlink_packet(DATA).unwrap(), |
| uevent! { |
| action: ActionType::Offline, |
| devpath: "/devices/platform/serial8250/tty/ttyS6", |
| subsystem: "tty", |
| env: { |
| "ACTION" => "offline", |
| "DEVPATH" => "/devices/platform/serial8250/tty/ttyS6", |
| "SUBSYSTEM" => "tty", |
| "SYNTH_UUID" => "0", |
| "MAJOR" => "4", |
| "MINOR" => "70", |
| "DEVNAME" => "ttyS6", |
| "SEQNUM" => "3475", |
| }, |
| seq: 3475 |
| } |
| ); |
| } |
| |
| #[test] |
| fn bind_uevent() { |
| const DATA: &[u8] = b"bind@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=bind\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SYNTH_UUID=0\0\ |
| MAJOR=4\0\ |
| MINOR=70\0\ |
| DEVNAME=ttyS6\0\ |
| SEQNUM=3476"; |
| assert_eq!( |
| UEvent::from_netlink_packet(DATA).unwrap(), |
| uevent! { |
| action: ActionType::Bind, |
| devpath: "/devices/platform/serial8250/tty/ttyS6", |
| subsystem: "tty", |
| env: { |
| "ACTION" => "bind", |
| "DEVPATH" => "/devices/platform/serial8250/tty/ttyS6", |
| "SUBSYSTEM" => "tty", |
| "SYNTH_UUID" => "0", |
| "MAJOR" => "4", |
| "MINOR" => "70", |
| "DEVNAME" => "ttyS6", |
| "SEQNUM" => "3476", |
| }, |
| seq: 3476 |
| } |
| ); |
| } |
| |
| #[test] |
| fn unbind_uevent() { |
| const DATA: &[u8] = b"unbind@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=unbind\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SYNTH_UUID=0\0\ |
| MAJOR=4\0\ |
| MINOR=70\0\ |
| DEVNAME=ttyS6\0\ |
| SEQNUM=3477"; |
| assert_eq!( |
| UEvent::from_netlink_packet(DATA).unwrap(), |
| uevent! { |
| action: ActionType::Unbind, |
| devpath: "/devices/platform/serial8250/tty/ttyS6", |
| subsystem: "tty", |
| env: { |
| "ACTION" => "unbind", |
| "DEVPATH" => "/devices/platform/serial8250/tty/ttyS6", |
| "SUBSYSTEM" => "tty", |
| "SYNTH_UUID" => "0", |
| "MAJOR" => "4", |
| "MINOR" => "70", |
| "DEVNAME" => "ttyS6", |
| "SEQNUM" => "3477", |
| }, |
| seq: 3477 |
| } |
| ); |
| } |
| |
| #[test] |
| fn invalid_event() { |
| const DATA: &[u8] = b"hello@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=hello\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SEQNUM=3477"; |
| assert!(UEvent::from_netlink_packet(DATA).is_err()); |
| } |
| |
| #[test] |
| fn missing_action() { |
| const DATA: &[u8] = b"add@/devices/platform/serial8250/tty/ttyS6\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty\0\ |
| SEQNUM=3477"; |
| assert!(UEvent::from_netlink_packet(DATA).is_err()); |
| } |
| |
| #[test] |
| fn missing_devpath() { |
| const DATA: &[u8] = b"add@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=unbind\0\ |
| SUBSYSTEM=tty\0\ |
| SEQNUM=3477"; |
| assert!(UEvent::from_netlink_packet(DATA).is_err()); |
| } |
| |
| #[test] |
| fn missing_subsystem() { |
| const DATA: &[u8] = b"add@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=unbind\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SEQNUM=3477"; |
| assert!(UEvent::from_netlink_packet(DATA).is_err()); |
| } |
| |
| #[test] |
| fn missing_seqnum() { |
| const DATA: &[u8] = b"add@/devices/platform/serial8250/tty/ttyS6\0\ |
| ACTION=unbind\0\ |
| DEVPATH=/devices/platform/serial8250/tty/ttyS6\0\ |
| SUBSYSTEM=tty"; |
| assert!(UEvent::from_netlink_packet(DATA).is_err()); |
| } |
| } |
