Initial Binder Rust crate
This crate exposes an idiomatic Binder interface for Rust clients and
services. This interface is primarily designed for use by the
forthcoming Rust backend for the AIDL compiler. The crate links against
the stable NDK version of the libbinder interface and therefore can
be used by APEX packages.
Test: atest rustBinderTest libbinder_rs-internal_test
Bug: 161559357
Change-Id: I2e9b800186f24217edeb1c3778f13902a3cca2fd
diff --git a/libs/binder/rust/src/state.rs b/libs/binder/rust/src/state.rs
new file mode 100644
index 0000000..992f074
--- /dev/null
+++ b/libs/binder/rust/src/state.rs
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2020 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 crate::sys;
+
+use libc::{pid_t, uid_t};
+
+/// Static utility functions to manage Binder process state.
+pub struct ProcessState;
+
+impl ProcessState {
+ /// Start the Binder IPC thread pool
+ pub fn start_thread_pool() {
+ unsafe {
+ // Safety: Safe FFI
+ sys::ABinderProcess_startThreadPool();
+ }
+ }
+
+ /// Set the maximum number of threads that can be started in the threadpool.
+ ///
+ /// By default, after startThreadPool is called, this is 15. If it is called
+ /// additional times, it will only prevent the kernel from starting new
+ /// threads and will not delete already existing threads.
+ pub fn set_thread_pool_max_thread_count(num_threads: u32) {
+ unsafe {
+ // Safety: Safe FFI
+ sys::ABinderProcess_setThreadPoolMaxThreadCount(num_threads);
+ }
+ }
+
+ /// Block on the Binder IPC thread pool
+ pub fn join_thread_pool() {
+ unsafe {
+ // Safety: Safe FFI
+ sys::ABinderProcess_joinThreadPool();
+ }
+ }
+}
+
+/// Static utility functions to manage Binder thread state.
+pub struct ThreadState;
+
+impl ThreadState {
+ /// This returns the calling UID assuming that this thread is called from a
+ /// thread that is processing a binder transaction (for instance, in the
+ /// implementation of
+ /// [`Remotable::on_transact`](crate::Remotable::on_transact)).
+ ///
+ /// This can be used with higher-level system services to determine the
+ /// caller's identity and check permissions.
+ ///
+ /// Available since API level 29.
+ ///
+ /// \return calling uid or the current process's UID if this thread isn't
+ /// processing a transaction.
+ pub fn get_calling_uid() -> uid_t {
+ unsafe {
+ // Safety: Safe FFI
+ sys::AIBinder_getCallingUid()
+ }
+ }
+
+ /// This returns the calling PID assuming that this thread is called from a
+ /// thread that is processing a binder transaction (for instance, in the
+ /// implementation of
+ /// [`Remotable::on_transact`](crate::Remotable::on_transact)).
+ ///
+ /// This can be used with higher-level system services to determine the
+ /// caller's identity and check permissions. However, when doing this, one
+ /// should be aware of possible TOCTOU problems when the calling process
+ /// dies and is replaced with another process with elevated permissions and
+ /// the same PID.
+ ///
+ /// Available since API level 29.
+ ///
+ /// \return calling pid or the current process's PID if this thread isn't
+ /// processing a transaction.
+ ///
+ /// If the transaction being processed is a oneway transaction, then this
+ /// method will return 0.
+ pub fn get_calling_pid() -> pid_t {
+ unsafe {
+ // Safety: Safe FFI
+ sys::AIBinder_getCallingPid()
+ }
+ }
+}