track poller and daemon fds like the rest

src/daemon_tokfd.rs

@@ -1,8 +1,114 @@
-use std::os::fd::RawFd;
+use std::{os::fd::RawFd, sync::OnceLock};
 
-use iddqd::BiHashItem;
+use circular_buffer::CircularBuffer;
+use iddqd::{BiHashItem, IdOrdItem};
 use mio::Token;
 
+use crate::prelude::*;
+
+const ERROR_BUFFER_LEN: usize = 8;
+
+#[derive(Debug)]
+pub struct FdInfo {
+    pub fd: RawFd,
+    pub kind: FdKind,
+    pub name: OnceLock<Box<OsStr>>,
+    pub error_buffer: CircularBuffer<ERROR_BUFFER_LEN, IoError>,
+}
+
+impl FdInfo {
+    pub fn new<Fd: AsRawFd>(fd: Fd, kind: FdKind) -> Self {
+        Self {
+            fd: fd.as_raw_fd(),
+            kind,
+            name: Default::default(),
+            error_buffer: Default::default(),
+        }
+    }
+
+    pub fn new_with_name<Fd: AsRawFd>(fd: Fd, kind: FdKind, name: Box<OsStr>) -> Self {
+        Self {
+            fd: fd.as_raw_fd(),
+            kind,
+            name: OnceLock::from(name),
+            error_buffer: Default::default(),
+        }
+    }
+}
+
+impl FdInfo {
+    pub(crate) fn guess_name<Fd: AsRawFd>(fd: Fd) -> Result<Box<OsStr>, IoError> {
+        let dev_fd_path = Path::new("/dev/fd").join(fd.as_raw_fd().to_string());
+
+        fs_err::read_link(dev_fd_path)
+            .map(PathBuf::into_os_string)
+            .map(OsString::into_boxed_os_str)
+    }
+
+    pub fn name(&self) -> &OsStr {
+        if let Some(name) = self.name.get() {
+            return name;
+        }
+
+        match Self::guess_name(self.fd) {
+            Ok(name) => {
+                let prev = self.name.set(Box::from(name));
+                debug_assert_eq!(prev, Ok(()));
+            },
+            Err(e) => {
+                warn!(
+                    "can't read link for {} /dev/fd/{}: {e}",
+                    self.kind.name_str(),
+                    self.fd,
+                );
+                return OsStr::new("«unknown»");
+            },
+        }
+
+        self.name.get().unwrap_or_else(|| unreachable!())
+    }
+}
+
+impl IdOrdItem for FdInfo {
+    type Key<'a> = &'a RawFd;
+
+    fn key(&self) -> &RawFd {
+        &self.fd
+    }
+
+    iddqd::id_upcast!();
+}
+
+#[derive(Copy)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[non_exhaustive]
+pub enum FdKind {
+    File,
+    Socket,
+    SockStream,
+    Poller,
+    Unknown,
+}
+
+impl FdKind {
+    pub fn name_str(self) -> &'static str {
+        use FdKind::*;
+        match self {
+            File => "file",
+            Socket => "socket",
+            SockStream => "socket stream",
+            Poller => "poller",
+            Unknown => "«unknown»",
+        }
+    }
+}
+
+impl Default for FdKind {
+    fn default() -> FdKind {
+        FdKind::Unknown
+    }
+}
+
 #[derive(Copy)]
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct TokenFd {