fd_server: use RwLock instead of Mutex
`nix::dir::Dir` isn't Sync (required by `RwLock`), so I had to replace
it with `OwnedFd`.
Bug: 220386264
Test: atest AuthFsHostTest
Test: performance change before vs after is hard to tell
Change-Id: Ib3fd9047970a856b532234f0bebad652172e12de
diff --git a/authfs/fd_server/src/common.rs b/authfs/fd_server/src/common.rs
new file mode 100644
index 0000000..f836bac
--- /dev/null
+++ b/authfs/fd_server/src/common.rs
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use std::fs::File;
+use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
+
+// TODO: Remove if/when std::os::unix::io::OwnedFd is standardized.
+pub struct OwnedFd {
+ owner: File,
+}
+
+impl FromRawFd for OwnedFd {
+ unsafe fn from_raw_fd(fd: RawFd) -> Self {
+ OwnedFd { owner: File::from_raw_fd(fd) }
+ }
+}
+
+impl AsRawFd for OwnedFd {
+ fn as_raw_fd(&self) -> RawFd {
+ self.owner.as_raw_fd()
+ }
+}