4 files changed, 281 insertions, 0 deletions
diff --git a/third_party/rust/devd-rs/src/data.rs b/third_party/rust/devd-rs/src/data.rs
new file mode 100644
index 0000000000..52084362e5
--- /dev/null
+++ b/third_party/rust/devd-rs/src/data.rs
@@ -0,0 +1,9 @@
+pub use std::collections::BTreeMap;
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Event {
+    Notify { system: String, subsystem: String, kind: String, data: BTreeMap<String, String> },
+    Attach { dev: String, parent: BTreeMap<String, String>, location: String },
+    Detach { dev: String, parent: BTreeMap<String, String>, location: String },
+    Nomatch { parent: BTreeMap<String, String>, location: String },
+}
diff --git a/third_party/rust/devd-rs/src/lib.rs b/third_party/rust/devd-rs/src/lib.rs
new file mode 100644
index 0000000000..8c863e856e
--- /dev/null
+++ b/third_party/rust/devd-rs/src/lib.rs
@@ -0,0 +1,93 @@
+pub mod data;
+pub mod parser;
+pub mod result;
+
+use io::{BufRead, BufReader};
+use libc::{c_int, connect, nfds_t, poll, pollfd, sockaddr_un, socket, AF_UNIX, POLLIN, SOCK_SEQPACKET};
+use std::cmp::Ordering;
+use std::os::unix::io::{FromRawFd, RawFd};
+use std::os::unix::net::UnixStream;
+use std::{io, mem, ptr};
+
+pub use data::*;
+pub use result::*;
+
+const SOCKET_PATH: &str = "/var/run/devd.seqpacket.pipe";
+
+pub fn parse_devd_event(event: &str) -> Result<Event> {
+    match parser::event(event) {
+        Ok((_, x)) => Ok(x),
+        _ => Err(Error::Parse),
+    }
+}
+
+#[derive(Debug)]
+pub struct Context {
+    sock: BufReader<UnixStream>,
+    sockfd: RawFd,
+    buffer: String,
+}
+
+impl Context {
+    pub fn new() -> Result<Context> {
+        unsafe {
+            let sockfd = socket(AF_UNIX, SOCK_SEQPACKET, 0);
+            if sockfd < 0 {
+                return Err(io::Error::last_os_error().into());
+            }
+            let mut sockaddr = sockaddr_un { sun_family: AF_UNIX as _, ..mem::zeroed() };
+            ptr::copy_nonoverlapping(SOCKET_PATH.as_ptr(), sockaddr.sun_path.as_mut_ptr() as *mut u8, SOCKET_PATH.len());
+            if connect(
+                sockfd,
+                &sockaddr as *const sockaddr_un as *const _,
+                (mem::size_of_val(&AF_UNIX) + SOCKET_PATH.len()) as _,
+            ) < 0
+            {
+                return Err(io::Error::last_os_error().into());
+            }
+            Ok(Context {
+                sock: BufReader::new(UnixStream::from_raw_fd(sockfd)),
+                sockfd,
+                buffer: String::new(),
+            })
+        }
+    }
+
+    pub fn wait_for_event_raw_internal(&mut self, timeout_ms: usize) -> Result<&str> {
+        let mut fds = [pollfd { fd: self.sockfd, events: POLLIN, revents: 0 }];
+        let x = unsafe { poll((&mut fds).as_mut_ptr(), fds.len() as nfds_t, timeout_ms as c_int) };
+
+        match x.cmp(&0) {
+            Ordering::Less => Err(io::Error::last_os_error().into()),
+            Ordering::Equal => Err(Error::Timeout),
+            Ordering::Greater => {
+                self.buffer.clear();
+                self.sock.read_line(&mut self.buffer)?;
+                Ok(&self.buffer)
+            }
+        }
+    }
+
+    /// Waits for an event using poll(), reads it but does not parse
+    pub fn wait_for_event_raw(&mut self, timeout_ms: usize) -> Result<String> {
+        self.wait_for_event_raw_internal(timeout_ms).map(ToOwned::to_owned)
+    }
+
+    /// Waits for an event using poll(), reads and parses it
+    pub fn wait_for_event(&mut self, timeout_ms: usize) -> Result<Event> {
+        self.wait_for_event_raw_internal(timeout_ms).and_then(parse_devd_event)
+    }
+
+    /// Returns the devd socket file descriptor in case you want to select/poll on it together with
+    /// other file descriptors
+    pub fn fd(&self) -> RawFd {
+        self.sockfd
+    }
+
+    /// Reads an event and parses it. Use when polling on the raw fd by yourself
+    pub fn read_event(&mut self) -> Result<Event> {
+        self.buffer.clear();
+        self.sock.read_line(&mut self.buffer)?;
+        parse_devd_event(&self.buffer)
+    }
+}
diff --git a/third_party/rust/devd-rs/src/parser.rs b/third_party/rust/devd-rs/src/parser.rs
new file mode 100644
index 0000000000..ee3c0511e9
--- /dev/null
+++ b/third_party/rust/devd-rs/src/parser.rs
@@ -0,0 +1,153 @@
+use crate::data::*;
+
+use nom::{
+    branch::alt,
+    bytes::complete::{tag, take_while},
+    character::complete::{alphanumeric1, char, multispace0, multispace1},
+    combinator::success,
+    multi::fold_many0,
+    sequence::{delimited, preceded, terminated, tuple},
+    IResult, Parser,
+};
+
+/// Parse a single value, which is either a quoted string, or a word without whitespace
+fn val(input: &str) -> IResult<&str, &str, ()> {
+    alt((delimited(char('"'), take_while(|c| c != '"'), char('"')), take_while(|c| c != '\n' && c != ' '))).parse(input)
+}
+
+/// Parse a key followed by a value, separated by =
+fn keyval(input: &str) -> IResult<&str, (&str, &str), ()> {
+    terminated(alphanumeric1, char('=')).and(val).parse(input)
+}
+
+/// Parser any number of key-value pairs, separated by 0 or more whitespace
+fn keyvals(input: &str) -> IResult<&str, BTreeMap<String, String>, ()> {
+    fold_many0(terminated(keyval, multispace0), BTreeMap::new, |mut map, (key, value)| {
+        map.insert(key.to_owned(), value.to_owned());
+        map
+    })
+    .parse(input)
+}
+
+/// Parse a key-value pair, where the key is a specific tag, separated by =,
+/// terminated by whitespace
+fn keyed_val<'i>(key: &'static str) -> impl Parser<&'i str, &'i str, ()> {
+    terminated(preceded(terminated(tag(key), char('=')), val), multispace1)
+}
+
+fn notify(input: &str) -> IResult<&str, Event, ()> {
+    preceded(char('!'), tuple((keyed_val("system"), keyed_val("subsystem"), keyed_val("type"), keyvals)))
+        .map(|(sys, subsys, kind, data)| Event::Notify {
+            system: sys.to_owned(),
+            subsystem: subsys.to_owned(),
+            kind: kind.to_owned(),
+            data,
+        })
+        .parse(input)
+}
+
+/// Parse a key-value pair, where the key is a specific tag, separated by
+/// whitespace
+fn event_param<'i, T>(key: &'static str, value: impl Parser<&'i str, T, ()>) -> impl Parser<&'i str, T, ()> {
+    preceded(terminated(tag(key), multispace1), value)
+}
+
+fn generic_event<'i, T>(prefix: char, dev: impl Parser<&'i str, T, ()>) -> impl Parser<&'i str, (T, BTreeMap<String, String>, &'i str), ()> {
+    tuple((
+        terminated(preceded(char(prefix), dev), multispace1),
+        event_param("at", keyvals),
+        event_param("on", val),
+    ))
+}
+
+fn attach(input: &str) -> IResult<&str, Event, ()> {
+    generic_event('+', alphanumeric1).map(|(dev, parent, loc)| Event::Attach { dev: dev.to_owned(), parent, location: loc.to_owned() }).parse(input)
+}
+
+fn detach(input: &str) -> IResult<&str, Event, ()> {
+    generic_event('-', alphanumeric1).map(|(dev, parent, loc)| Event::Detach { dev: dev.to_owned(), parent, location: loc.to_owned() }).parse(input)
+}
+
+fn nomatch(input: &str) -> IResult<&str, Event, ()> {
+    generic_event('?', success(())).map(|((), parent, loc)| Event::Nomatch { parent, location: loc.to_owned() }).parse(input)
+}
+
+pub fn event(input: &str) -> IResult<&str, Event, ()> {
+    alt((notify, attach, detach, nomatch)).parse(input)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_notify() {
+        let txt = "!system=USB subsystem=INTERFACE type=ATTACH ugen=ugen0.2 vendor=0x1050 sernum=\"\" mode=host\n";
+        let res = event(txt);
+        let mut data = BTreeMap::new();
+        data.insert("ugen".to_owned(), "ugen0.2".to_owned());
+        data.insert("vendor".to_owned(), "0x1050".to_owned());
+        data.insert("sernum".to_owned(), "".to_owned());
+        data.insert("mode".to_owned(), "host".to_owned());
+        assert_eq!(
+            res,
+            Ok((
+                "",
+                Event::Notify {
+                    system: "USB".to_owned(),
+                    subsystem: "INTERFACE".to_owned(),
+                    kind: "ATTACH".to_owned(),
+                    data,
+                }
+            ))
+        )
+    }
+
+    #[test]
+    fn test_attach() {
+        let txt = "+uhid1 at bus=0 sernum=\"\" on uhub1";
+        let res = event(txt);
+        let mut data = BTreeMap::new();
+        data.insert("bus".to_owned(), "0".to_owned());
+        data.insert("sernum".to_owned(), "".to_owned());
+        assert_eq!(
+            res,
+            Ok((
+                "",
+                Event::Attach {
+                    dev: "uhid1".to_owned(),
+                    parent: data,
+                    location: "uhub1".to_owned(),
+                }
+            ))
+        )
+    }
+
+    #[test]
+    fn test_detach() {
+        let txt = "-uhid1 at  on uhub1";
+        let res = event(txt);
+        let data = BTreeMap::new();
+        assert_eq!(
+            res,
+            Ok((
+                "",
+                Event::Detach {
+                    dev: "uhid1".to_owned(),
+                    parent: data,
+                    location: "uhub1".to_owned(),
+                }
+            ))
+        )
+    }
+
+    #[test]
+    fn test_nomatch() {
+        let txt = "? at bus=0 on uhub1";
+        let res = event(txt);
+        let mut data = BTreeMap::new();
+        data.insert("bus".to_owned(), "0".to_owned());
+
+        assert_eq!(res, Ok(("", Event::Nomatch { parent: data, location: "uhub1".to_owned() })))
+    }
+}
diff --git a/third_party/rust/devd-rs/src/result.rs b/third_party/rust/devd-rs/src/result.rs
new file mode 100644
index 0000000000..2b47b8012c
--- /dev/null
+++ b/third_party/rust/devd-rs/src/result.rs
@@ -0,0 +1,26 @@
+use std::{io, result};
+
+#[derive(Debug)]
+pub enum Error {
+    IoError(io::Error),
+    Timeout,
+    Parse,
+}
+
+impl From<Error> for io::Error {
+    fn from(val: Error) -> Self {
+        match val {
+            Error::IoError(e) => e,
+            Error::Timeout => io::Error::new(io::ErrorKind::Other, "devd poll timeout"),
+            Error::Parse => io::Error::new(io::ErrorKind::Other, "devd parse error"),
+        }
+    }
+}
+
+impl From<io::Error> for Error {
+    fn from(err: io::Error) -> Error {
+        Error::IoError(err)
+    }
+}
+
+pub type Result<T> = result::Result<T, Error>;