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Commit b4eafd35 authored by Devin Moore's avatar Devin Moore
Browse files

Add Accessor::from_binder 

This allows other processes to host the Accessor object from libbinder.
This can be useful when another process has the sepolicy permissions to
create the connection.

Test: atest rustBinderTest
Bug: 358427181

Change-Id: Iedc51e2fa5b50e91438690d5d551156927a91807
parent 91088b92

libs/binder/rust/src/system_only.rs

+26 −0
Original line number Diff line number Diff line
@@ -91,6 +91,32 @@ impl Accessor { 
        Accessor { accessor }

    }



    /// Creates a new Accessor instance based on an existing Accessor's binder.

    /// This is useful when the Accessor instance is hosted in another process

    /// that has the permissions to create the socket connection FD.

    ///

    /// The `instance` argument must match the instance that the original Accessor

    /// is responsible for.

    /// `instance` must not contain null bytes and is used to create a CString to

    /// pass through FFI.

    /// The `binder` argument must be a valid binder from an Accessor

    pub fn from_binder(instance: &str, binder: SpIBinder) -> Option<Accessor> {

        let inst = CString::new(instance).unwrap();



        // Safety: All `SpIBinder` objects (the `binder` argument) hold a valid pointer

        // to an `AIBinder` that is guaranteed to remain valid for the lifetime of the

        // SpIBinder. `ABinderRpc_Accessor_fromBinder` creates a new pointer to that binder

        // that it is responsible for.

        // The `inst` argument is a new CString that will copied by

        // `ABinderRpc_Accessor_fromBinder` and not modified.

        let accessor =

            unsafe { sys::ABinderRpc_Accessor_fromBinder(inst.as_ptr(), binder.as_raw()) };

        if accessor.is_null() {

            return None;

        }

        Some(Accessor { accessor })

    }



    /// Get the underlying binder for this Accessor for when it needs to be either

    /// registered with service manager or sent to another process.

    pub fn as_binder(&self) -> Option<SpIBinder> {

libs/binder/rust/tests/integration.rs

+28 −0
Original line number Diff line number Diff line
@@ -1038,6 +1038,34 @@ mod tests { 
        assert!(deleted.load(Ordering::Relaxed));

    }



    #[test]

    fn test_accessor_from_accessor_binder() {

        let get_connection_info = move |_instance: &str| None;

        let accessor = Accessor::new("foo.service", get_connection_info);

        let accessor2 =

            Accessor::from_binder("foo.service", accessor.as_binder().unwrap()).unwrap();

        assert_eq!(accessor.as_binder(), accessor2.as_binder());

    }



    #[test]

    fn test_accessor_from_non_accessor_binder() {

        let service_name = "rust_test_ibinder";

        let _process = ScopedServiceProcess::new(service_name);

        let binder = binder::get_service(service_name).unwrap();

        assert!(binder.is_binder_alive());



        let accessor = Accessor::from_binder("rust_test_ibinder", binder);

        assert!(accessor.is_none());

    }



    #[test]

    fn test_accessor_from_wrong_accessor_binder() {

        let get_connection_info = move |_instance: &str| None;

        let accessor = Accessor::new("foo.service", get_connection_info);

        let accessor2 = Accessor::from_binder("NOT.foo.service", accessor.as_binder().unwrap());

        assert!(accessor2.is_none());

    }



    #[tokio::test]

    async fn reassociate_rust_binder_async() {

        let service_name = "testing_service";