Rewrite OwnedFd::into_raw_fd to avoid dropping the handle, and to avoid unsafe.

Author: sunfishcode

src/io/owned_fd.rs

@@ -98,9 +98,10 @@ impl AsRawFd for OwnedFd {
 
 impl IntoRawFd for OwnedFd {
     #[inline]
-    fn into_raw_fd(mut self) -> RawFd {
-        // Safety: We're consume `self`, so we'll never use it again.
-        unsafe { ManuallyDrop::take(&mut self.inner) }.into_raw_fd()
+    fn into_raw_fd(self) -> RawFd {
+        let raw_fd = self.inner.as_fd().as_raw_fd();
+        forget(self);
+        raw_fd
     }
 }
 

tests/io/from_into.rs

@@ -0,0 +1,28 @@
+#[cfg(not(target_os = "redox"))]
+#[test]
+fn test_owned() {
+    use io_lifetimes::AsFd;
+    #[cfg(unix)]
+    use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd};
+    #[cfg(target_os = "wasi")]
+    use std::os::wasi::io::{AsRawFd, FromRawFd, IntoRawFd};
+
+    let file = rsix::fs::openat(
+        &rsix::fs::cwd(),
+        "Cargo.toml",
+        rsix::fs::OFlags::RDONLY,
+        rsix::fs::Mode::empty(),
+    )
+    .unwrap();
+
+    let raw = file.as_raw_fd();
+    assert_eq!(raw, file.as_fd().as_raw_fd());
+
+    let owned: io_lifetimes::OwnedFd = file.into();
+    let inner = owned.into_raw_fd();
+    assert_eq!(raw, inner);
+
+    let new = unsafe { rsix::io::OwnedFd::from_raw_fd(inner) };
+    let mut buf = [0_u8; 4];
+    let _ = rsix::io::read(&new, &mut buf).unwrap();
+}

tests/io/main.rs

@@ -5,6 +5,7 @@ mod dup2_to_replace_stdio;
 mod epoll;
 mod error;
 mod eventfd;
+mod from_into;
 mod isatty;
 mod mmap;
 #[cfg(not(target_os = "redox"))] // redox doesn't have cwd/openat