Add support for abstract sockets

In #146, I introduced a bug that prevented abstract sockets from
working. I passed the path straight into
rustix::net::SocketAddrUnix::new, which fails if it receives an abstract
socket.

This commit fixes this issue by explicitly checking for abstract
sockets. If it sees that the path it's receiving is abstract, it will
pass the path's bytes to new_abstract_socket() instead.

This should fix the issue that is occurring in dbus2/zbus#517

Signed-off-by: John Nunley <[email protected]>

src/lib.rs

@@ -1847,12 +1847,20 @@ impl Async<UnixStream> {
     /// # std::io::Result::Ok(()) });
     /// ```
     pub async fn connect<P: AsRef<Path>>(path: P) -> io::Result<Async<UnixStream>> {
+        use std::os::unix::ffi::OsStrExt;
+
+        // SocketAddrUnix::new() will throw EINVAL when a path with a zero in it is passed in.
+        // However, some users expect to be able to pass in paths to abstract sockets, which
+        // triggers this error as it has a zero in it. Therefore, if a path starts with a zero,
+        // make it an abstract socket.
+        let path = path.as_ref().as_os_str();
+        let address = match path.as_bytes().first() {
+            Some(0) => rn::SocketAddrUnix::new_abstract_name(path.as_bytes())?,
+            _ => rn::SocketAddrUnix::new(path)?,
+        };
+
         // Begin async connect.
-        let socket = connect(
-            rn::SocketAddrUnix::new(path.as_ref())?.into(),
-            rn::AddressFamily::UNIX,
-            None,
-        )?;
+        let socket = connect(address.into(), rn::AddressFamily::UNIX, None)?;
         // Use new_nonblocking because connect already sets socket to non-blocking mode.
         let stream = Async::new_nonblocking(UnixStream::from(socket))?;