Improve unix

src/lib.rs

@@ -541,28 +541,35 @@ mod tests {
                 .collect::<Result<Vec<DirEntry>>>()?
                 .len()
         );
-        let mut options = OpenOptions::default();
-        options.create_new(true).write(OpenOptionsWriteMode::Write);
-        options.open_at(&mut parent_dir, "1")?;
-        options.open_at(&mut parent_dir, "2")?;
-        options.mkdir_at(&mut parent_dir, "child")?;
-        options.open_at(&mut parent_dir, "child\\3")?;
-        let children = read_dir(&mut parent_dir)?.collect::<Result<Vec<_>>>()?;
         let dir_present =
             |children: &Vec<DirEntry>, name: &OsStr| children.iter().any(|e| e.name() == name);
-        assert!(dir_present(&children, OsStr::new("1")), "{:?}", children);
-        assert!(dir_present(&children, OsStr::new("2")), "{:?}", children);
-        assert!(
-            dir_present(&children, OsStr::new("child")),
-            "{:?}",
-            children
-        );
-        let mut child = OpenOptions::default()
-            .read(true)
-            .open_at(&mut parent_dir, "child")?;
-        let children = read_dir(&mut child)?.collect::<Result<Vec<_>>>()?;
-        assert_eq!(3, children.len());
-        assert!(dir_present(&children, OsStr::new("3")), "{:?}", children);
+        {
+            let mut options = OpenOptions::default();
+            options.create_new(true).write(OpenOptionsWriteMode::Write);
+            options.open_at(&mut parent_dir, "1")?;
+            options.open_at(&mut parent_dir, "2")?;
+            options.open_at(&mut options.mkdir_at(&mut parent_dir, "child")?, "3")?;
+            let children = read_dir(&mut parent_dir)?.collect::<Result<Vec<_>>>()?;
+            assert!(dir_present(&children, OsStr::new("1")), "{:?}", children);
+            assert!(dir_present(&children, OsStr::new("2")), "{:?}", children);
+            assert!(
+                dir_present(&children, OsStr::new("child")),
+                "{:?}",
+                children
+            );
+        }
+        {
+            let mut child = OpenOptions::default()
+                .read(true)
+                .open_at(&mut parent_dir, "child")?;
+            // Something is permitting the fd for child to be dropped before the
+            // read_dir fcntl to duplicate the fd. Possibly the FD is writing
+            // over some other fd which is then separately dropped?
+            // eprintln!("More Magic");
+            let children = read_dir(&mut child)?.collect::<Result<Vec<_>>>()?;
+            assert_eq!(3, children.len(), "{:?}", children);
+            assert!(dir_present(&children, OsStr::new("3")), "{:?}", children);
+        }
         Ok(())
     }
 }

src/unix.rs

@@ -195,7 +195,8 @@ impl<'a> ReadDirImpl<'a> {
     pub fn new(dir_file: &'a mut File) -> Result<Self> {
         // clone the FD - Nix takes ownership of the FD, but we're not
         // implementing TryInto here.
-        let new_fd = cvt_r(|| unsafe { libc::fcntl(dir_file.as_raw_fd(), libc::F_DUPFD_CLOEXEC) })?;
+        let new_fd =
+            cvt_r(|| unsafe { libc::fcntl(dir_file.as_raw_fd(), libc::F_DUPFD_CLOEXEC, 0) })?;
         Ok(ReadDirImpl {
             iter: Dir::from_fd(new_fd)?.into_iter(),
             _phantom: PhantomData,
@@ -213,15 +214,14 @@ impl Iterator for ReadDirImpl<'_> {
             Some(Err(_e)) => Some(Err(std::io::Error::from_raw_os_error(errno::errno()))),
             Some(Ok(e)) => {
                 let name = OsStr::from_bytes(e.file_name().to_bytes()).to_os_string();
-                Some(Ok(DirEntryImpl { e, name }))
+                Some(Ok(DirEntryImpl { name }))
             }
         }
     }
 }
 
 #[derive(Debug)]
 pub(crate) struct DirEntryImpl {
-    e: dir::Entry,
     name: OsString,
 }