auto merge of #13690 : alexcrichton/rust/unlink-unix-pipe, r=brson

This prevents unix sockets from remaining on the system all over the place, and
more closely mirrors the behavior of libuv and windows pipes.

src/libnative/io/pipe_unix.rs

@@ -232,11 +232,14 @@ impl UnixDatagram {
 
 pub struct UnixListener {
     inner: Inner,
+    path: CString,
 }
 
 impl UnixListener {
     pub fn bind(addr: &CString) -> IoResult<UnixListener> {
-        bind(addr, libc::SOCK_STREAM).map(|fd| UnixListener { inner: fd })
+        bind(addr, libc::SOCK_STREAM).map(|fd| {
+            UnixListener { inner: fd, path: addr.clone() }
+        })
     }
 
     fn fd(&self) -> fd_t { self.inner.fd }
@@ -283,3 +286,14 @@ impl rtio::RtioUnixAcceptor for UnixAcceptor {
         self.native_accept().map(|s| ~s as ~rtio::RtioPipe:Send)
     }
 }
+
+impl Drop for UnixListener {
+    fn drop(&mut self) {
+        // Unlink the path to the socket to ensure that it doesn't linger. We're
+        // careful to unlink the path before we close the file descriptor to
+        // prevent races where we unlink someone else's path.
+        unsafe {
+            let _ = libc::unlink(self.path.with_ref(|p| p));
+        }
+    }
+}

src/libstd/io/net/unix.rs

@@ -355,4 +355,20 @@ mod tests {
 
         rx.recv();
     })
+
+    iotest!(fn drop_removes_listener_path() {
+        let path = next_test_unix();
+        let l = UnixListener::bind(&path).unwrap();
+        assert!(path.exists());
+        drop(l);
+        assert!(!path.exists());
+    } #[cfg(not(windows))])
+
+    iotest!(fn drop_removes_acceptor_path() {
+        let path = next_test_unix();
+        let l = UnixListener::bind(&path).unwrap();
+        assert!(path.exists());
+        drop(l.listen().unwrap());
+        assert!(!path.exists());
+    } #[cfg(not(windows))])
 }