Unset FDSan tag when converting handle into other types

Bug: 359100544
Test: atest libnativewindow_rs-internal_test
Change-Id: Ib80d14277d9f695615fa0f07459d5c0bce4aeab9

Author: Ren-Pei Zeng

libs/nativewindow/rust/src/handle.rs

@@ -85,6 +85,12 @@ impl NativeHandle {
 
     /// Destroys the `NativeHandle`, taking ownership of the file descriptors it contained.
     pub fn into_fds(self) -> Vec<OwnedFd> {
+        // Unset FDSan tag since this `native_handle_t` is no longer the owner of the file
+        // descriptors after this function.
+        // SAFETY: Our wrapped `native_handle_t` pointer is always valid.
+        unsafe {
+            ffi::native_handle_unset_fdsan_tag(self.as_ref());
+        }
         let fds = self.data()[..self.fd_count()]
             .iter()
             .map(|fd| {
@@ -260,6 +266,29 @@ mod test {
         drop(cloned);
     }
 
+    #[test]
+    fn to_fds() {
+        let file = File::open("/dev/null").unwrap();
+        let original = NativeHandle::new(vec![file.into()], &[42]).unwrap();
+        assert_eq!(original.ints(), &[42]);
+        assert_eq!(original.fds().len(), 1);
+
+        let fds = original.into_fds();
+        assert_eq!(fds.len(), 1);
+    }
+
+    #[test]
+    fn to_aidl() {
+        let file = File::open("/dev/null").unwrap();
+        let original = NativeHandle::new(vec![file.into()], &[42]).unwrap();
+        assert_eq!(original.ints(), &[42]);
+        assert_eq!(original.fds().len(), 1);
+
+        let aidl = AidlNativeHandle::from(original);
+        assert_eq!(&aidl.ints, &[42]);
+        assert_eq!(aidl.fds.len(), 1);
+    }
+
     #[test]
     fn to_from_aidl() {
         let file = File::open("/dev/null").unwrap();