x11: dup fd before passing to shm_attach_fd

This function takes `Into<RawFdContainer>`. So it accepts an owned fd,
and closes it. So as long as the API is like this, we need to dup a new
fd it can close when calling it.

`Into<RawFdContainer>` is implemented for anything implementing `IntoRawFd`,
so passing `OwnedFd` works.

Fixes #168. Should be
backported to 0.3.x.

src/x11.rs

@@ -11,7 +11,10 @@ use raw_window_handle::{
     HasDisplayHandle, HasWindowHandle, RawDisplayHandle, RawWindowHandle, XcbDisplayHandle,
     XcbWindowHandle,
 };
-use rustix::{fd, mm, shm as posix_shm};
+use rustix::{
+    fd::{AsFd, BorrowedFd, OwnedFd},
+    mm, shm as posix_shm,
+};
 
 use std::{
     fmt,
@@ -618,7 +621,7 @@ impl ShmBuffer {
     ) -> Result<(), PushBufferError> {
         // Register the guard.
         let new_id = conn.generate_id()?;
-        conn.shm_attach_fd(new_id, fd::AsRawFd::as_raw_fd(&seg), true)?
+        conn.shm_attach_fd(new_id, seg.as_fd().try_clone_to_owned().unwrap(), true)?
             .ignore_error();
 
         // Take out the old one and detach it.
@@ -738,9 +741,9 @@ impl ShmSegment {
     }
 }
 
-impl fd::AsRawFd for ShmSegment {
-    fn as_raw_fd(&self) -> fd::RawFd {
-        self.id.as_raw_fd()
+impl AsFd for ShmSegment {
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        self.id.as_fd()
     }
 }
 
@@ -785,7 +788,7 @@ impl<D: ?Sized, W: ?Sized> Drop for X11Impl<D, W> {
 }
 
 /// Create a shared memory identifier.
-fn create_shm_id() -> io::Result<fd::OwnedFd> {
+fn create_shm_id() -> io::Result<OwnedFd> {
     use posix_shm::{Mode, ShmOFlags};
 
     let mut rng = fastrand::Rng::new();
@@ -838,7 +841,7 @@ fn is_shm_available(c: &impl Connection) -> bool {
     };
 
     let (attach, detach) = {
-        let attach = c.shm_attach_fd(seg_id, fd::AsRawFd::as_raw_fd(&seg), false);
+        let attach = c.shm_attach_fd(seg_id, seg.as_fd().try_clone_to_owned().unwrap(), false);
         let detach = c.shm_detach(seg_id);
 
         match (attach, detach) {