Implement epoll (#164)

Use the new epoll API from bytecodealliance/rustix#487.

Fixes #86.

Author: sunfishcode

c-scape/src/io/epoll.rs

@@ -1,5 +1,5 @@
-use rustix::fd::{FromRawFd, IntoRawFd, OwnedFd};
-use rustix::io::epoll::{CreateFlags, Epoll, Owning};
+use rustix::fd::{BorrowedFd, IntoRawFd};
+use rustix::io::epoll::{epoll_add, epoll_del, epoll_mod, CreateFlags, EventFlags, EventVec};
 
 use errno::{set_errno, Errno};
 use libc::c_int;
@@ -24,7 +24,7 @@ unsafe extern "C" fn epoll_create1(flags: c_int) -> c_int {
 
     let flags = CreateFlags::from_bits(flags as _).unwrap();
 
-    match convert_res(Epoll::new(flags, Owning::<OwnedFd>::new())) {
+    match convert_res(rustix::io::epoll::epoll_create(flags)) {
         Some(epoll) => epoll.into_raw_fd(),
         None => -1,
     }
@@ -38,27 +38,68 @@ unsafe extern "C" fn epoll_ctl(
     fd: c_int,
     event: *mut libc::epoll_event,
 ) -> c_int {
-    let epoll = Epoll::from_raw_fd(epfd);
+    libc!(libc::epoll_ctl(epfd, op, fd, event));
 
-    // let res = match op {
-    //     libc::EPOLL_CTL_ADD => epoll.add(),
-    // };
+    let epfd = BorrowedFd::borrow_raw(epfd);
+    let fd = BorrowedFd::borrow_raw(fd);
+    let res = match op {
+        libc::EPOLL_CTL_ADD => {
+            let libc::epoll_event { events, r#u64 } = event.read();
+            let events = EventFlags::from_bits(events).unwrap();
+            epoll_add(epfd, fd, r#u64, events)
+        }
+        libc::EPOLL_CTL_MOD => {
+            let libc::epoll_event { events, r#u64 } = event.read();
+            let events = EventFlags::from_bits(events).unwrap();
+            epoll_mod(epfd, fd, r#u64, events)
+        }
+        libc::EPOLL_CTL_DEL => epoll_del(epfd, fd),
+        _ => {
+            set_errno(Errno(libc::EINVAL));
+            return -1;
+        }
+    };
 
-    todo!()
+    match convert_res(res) {
+        Some(()) => 0,
+        None => -1,
+    }
 }
 
 #[no_mangle]
 unsafe extern "C" fn epoll_wait(
-    _epfd: c_int,
-    _events: *mut libc::epoll_event,
-    _maxevents: c_int,
-    _timeout: c_int,
+    epfd: c_int,
+    events: *mut libc::epoll_event,
+    maxevents: c_int,
+    timeout: c_int,
 ) -> c_int {
-    libc!(libc::epoll_wait(
-        _epfd,
-        _events,
-        _maxevents,
-        _timeout
-    ));
-    unimplemented!("epoll_wait")
+    libc!(libc::epoll_wait(epfd, events, maxevents, timeout));
+
+    if maxevents <= 0 {
+        set_errno(Errno(libc::EINVAL));
+        return -1;
+    }
+
+    // TODO: We should add an `EventVec::from_raw_parts` to allow `epoll_wait`
+    // to write events directly into the user's buffer, rather then allocating
+    // and copying here.
+    let mut events_vec = EventVec::with_capacity(maxevents as usize);
+    match convert_res(rustix::io::epoll::epoll_wait(
+        BorrowedFd::borrow_raw(epfd),
+        &mut events_vec,
+        timeout,
+    )) {
+        Some(()) => {
+            let mut events = events;
+            for (flags, data) in events_vec.iter() {
+                events.write(libc::epoll_event {
+                    events: flags.bits(),
+                    r#u64: data,
+                });
+                events = events.add(1);
+            }
+            events_vec.len() as c_int
+        }
+        None => -1,
+    }
 }

c-scape/src/io/mod.rs

@@ -1,7 +1,7 @@
 #[cfg(not(target_os = "wasi"))]
 mod dup;
-// #[cfg(any(target_os = "android", target_os = "linux"))]
-// mod epoll;
+#[cfg(any(target_os = "android", target_os = "linux"))]
+mod epoll;
 mod isatty;
 mod pipe;
 mod poll;