Merge "libbinder_rs: Move service manager code to separate module" into main (4d947f14) · Commits · e / os / android_frameworks_native

libs/binder/rust/src/lib.rs

+8 −7

Original line number	Diff line number	Diff line
		@@ -101,6 +101,8 @@ mod native;
		mod parcel;
		mod proxy;
		#[cfg(not(target_os = "trusty"))]
		mod service;
		#[cfg(not(target_os = "trusty"))]
		mod state;

		use binder_ndk_sys as sys;
		@@ -108,14 +110,13 @@ use binder_ndk_sys as sys;
		pub use crate::binder_async::{BinderAsyncPool, BoxFuture};
		pub use binder::{BinderFeatures, FromIBinder, IBinder, Interface, Strong, Weak};
		pub use error::{ExceptionCode, IntoBinderResult, Status, StatusCode};
		pub use native::{
		add_service, force_lazy_services_persist, is_handling_transaction, register_lazy_service,
		LazyServiceGuard,
		};
		pub use parcel::{ParcelFileDescriptor, Parcelable, ParcelableHolder};
		pub use proxy::{
		get_declared_instances, get_interface, get_service, is_declared, wait_for_interface,
		wait_for_service, DeathRecipient, SpIBinder, WpIBinder,
		pub use proxy::{DeathRecipient, SpIBinder, WpIBinder};
		#[cfg(not(target_os = "trusty"))]
		pub use service::{
		add_service, force_lazy_services_persist, get_declared_instances, get_interface, get_service,
		is_declared, is_handling_transaction, register_lazy_service, wait_for_interface,
		wait_for_service, LazyServiceGuard,
		};
		#[cfg(not(target_os = "trusty"))]
		pub use state::{ProcessState, ThreadState};

libs/binder/rust/src/native.rs

+1 −113

Original line number	Diff line number	Diff line
		@@ -23,12 +23,11 @@ use crate::proxy::SpIBinder;
		use crate::sys;

		use std::convert::TryFrom;
		use std::ffi::{c_void, CStr, CString};
		use std::ffi::{c_void, CStr};
		use std::io::Write;
		use std::mem::ManuallyDrop;
		use std::ops::Deref;
		use std::os::raw::c_char;
		use std::sync::Mutex;

		/// Rust wrapper around Binder remotable objects.
		///
		@@ -462,110 +461,6 @@ unsafe impl<B: Remotable> AsNative<sys::AIBinder> for Binder<B> {
		}
		}

		/// Register a new service with the default service manager.
		///
		/// Registers the given binder object with the given identifier. If successful,
		/// this service can then be retrieved using that identifier.
		///
		/// This function will panic if the identifier contains a 0 byte (NUL).
		pub fn add_service(identifier: &str, mut binder: SpIBinder) -> Result<()> {
		let instance = CString::new(identifier).unwrap();
		let status =
		// Safety: `AServiceManager_addService` expects valid `AIBinder` and C
		// string pointers. Caller retains ownership of both pointers.
		// `AServiceManager_addService` creates a new strong reference and copies
		// the string, so both pointers need only be valid until the call returns.
		unsafe { sys::AServiceManager_addService(binder.as_native_mut(), instance.as_ptr()) };
		status_result(status)
		}

		/// Register a dynamic service via the LazyServiceRegistrar.
		///
		/// Registers the given binder object with the given identifier. If successful,
		/// this service can then be retrieved using that identifier. The service process
		/// will be shut down once all registered services are no longer in use.
		///
		/// If any service in the process is registered as lazy, all should be, otherwise
		/// the process may be shut down while a service is in use.
		///
		/// This function will panic if the identifier contains a 0 byte (NUL).
		pub fn register_lazy_service(identifier: &str, mut binder: SpIBinder) -> Result<()> {
		let instance = CString::new(identifier).unwrap();
		// Safety: `AServiceManager_registerLazyService` expects valid `AIBinder` and C
		// string pointers. Caller retains ownership of both
		// pointers. `AServiceManager_registerLazyService` creates a new strong reference
		// and copies the string, so both pointers need only be valid until the
		// call returns.
		let status = unsafe {
		sys::AServiceManager_registerLazyService(binder.as_native_mut(), instance.as_ptr())
		};
		status_result(status)
		}

		/// Prevent a process which registers lazy services from being shut down even when none
		/// of the services is in use.
		///
		/// If persist is true then shut down will be blocked until this function is called again with
		/// persist false. If this is to be the initial state, call this function before calling
		/// register_lazy_service.
		///
		/// Consider using [`LazyServiceGuard`] rather than calling this directly.
		pub fn force_lazy_services_persist(persist: bool) {
		// Safety: No borrowing or transfer of ownership occurs here.
		unsafe { sys::AServiceManager_forceLazyServicesPersist(persist) }
		}

		/// An RAII object to ensure a process which registers lazy services is not killed. During the
		/// lifetime of any of these objects the service manager will not not kill the process even if none
		/// of its lazy services are in use.
		#[must_use]
		#[derive(Debug)]
		pub struct LazyServiceGuard {
		// Prevent construction outside this module.
		_private: (),
		}

		// Count of how many LazyServiceGuard objects are in existence.
		static GUARD_COUNT: Mutex<u64> = Mutex::new(0);

		impl LazyServiceGuard {
		/// Create a new LazyServiceGuard to prevent the service manager prematurely killing this
		/// process.
		pub fn new() -> Self {
		let mut count = GUARD_COUNT.lock().unwrap();
		*count += 1;
		if *count == 1 {
		// It's important that we make this call with the mutex held, to make sure
		// that multiple calls (e.g. if the count goes 1 -> 0 -> 1) are correctly
		// sequenced. (That also means we can't just use an AtomicU64.)
		force_lazy_services_persist(true);
		}
		Self { _private: () }
		}
		}

		impl Drop for LazyServiceGuard {
		fn drop(&mut self) {
		let mut count = GUARD_COUNT.lock().unwrap();
		*count -= 1;
		if *count == 0 {
		force_lazy_services_persist(false);
		}
		}
		}

		impl Clone for LazyServiceGuard {
		fn clone(&self) -> Self {
		Self::new()
		}
		}

		impl Default for LazyServiceGuard {
		fn default() -> Self {
		Self::new()
		}
		}

		/// Tests often create a base BBinder instance; so allowing the unit
		/// type to be remotable translates nicely to Binder::new(()).
		impl Remotable for () {
		@@ -590,10 +485,3 @@ impl Remotable for () {
		}

		impl Interface for () {}

		/// Determine whether the current thread is currently executing an incoming
		/// transaction.
		pub fn is_handling_transaction() -> bool {
		// Safety: This method is always safe to call.
		unsafe { sys::AIBinder_isHandlingTransaction() }
		}

libs/binder/rust/src/proxy.rs

+1 −97

Original line number	Diff line number	Diff line
		@@ -29,11 +29,10 @@ use crate::sys;

		use std::cmp::Ordering;
		use std::convert::TryInto;
		use std::ffi::{c_void, CStr, CString};
		use std::ffi::{c_void, CString};
		use std::fmt;
		use std::mem;
		use std::os::fd::AsRawFd;
		use std::os::raw::c_char;
		use std::ptr;
		use std::sync::Arc;

		@@ -129,14 +128,6 @@ impl SpIBinder {
		}
		}

		fn interface_cast<T: FromIBinder + ?Sized>(service: Option<SpIBinder>) -> Result<Strong<T>> {
		if let Some(service) = service {
		FromIBinder::try_from(service)
		} else {
		Err(StatusCode::NAME_NOT_FOUND)
		}
		}

		pub mod unstable_api {
		use super::{sys, SpIBinder};

		@@ -739,93 +730,6 @@ unsafe impl<T: Proxy> AsNative<sys::AIBinder> for T {
		}
		}

		/// Retrieve an existing service, blocking for a few seconds if it doesn't yet
		/// exist.
		pub fn get_service(name: &str) -> Option<SpIBinder> {
		let name = CString::new(name).ok()?;
		// Safety: `AServiceManager_getService` returns either a null pointer or a
		// valid pointer to an owned `AIBinder`. Either of these values is safe to
		// pass to `SpIBinder::from_raw`.
		unsafe { SpIBinder::from_raw(sys::AServiceManager_getService(name.as_ptr())) }
		}

		/// Retrieve an existing service, or start it if it is configured as a dynamic
		/// service and isn't yet started.
		pub fn wait_for_service(name: &str) -> Option<SpIBinder> {
		let name = CString::new(name).ok()?;
		// Safety: `AServiceManager_waitforService` returns either a null pointer or
		// a valid pointer to an owned `AIBinder`. Either of these values is safe to
		// pass to `SpIBinder::from_raw`.
		unsafe { SpIBinder::from_raw(sys::AServiceManager_waitForService(name.as_ptr())) }
		}

		/// Retrieve an existing service for a particular interface, blocking for a few
		/// seconds if it doesn't yet exist.
		pub fn get_interface<T: FromIBinder + ?Sized>(name: &str) -> Result<Strong<T>> {
		interface_cast(get_service(name))
		}

		/// Retrieve an existing service for a particular interface, or start it if it
		/// is configured as a dynamic service and isn't yet started.
		pub fn wait_for_interface<T: FromIBinder + ?Sized>(name: &str) -> Result<Strong<T>> {
		interface_cast(wait_for_service(name))
		}

		/// Check if a service is declared (e.g. in a VINTF manifest)
		pub fn is_declared(interface: &str) -> Result<bool> {
		let interface = CString::new(interface).or(Err(StatusCode::UNEXPECTED_NULL))?;

		// Safety: `interface` is a valid null-terminated C-style string and is only
		// borrowed for the lifetime of the call. The `interface` local outlives
		// this call as it lives for the function scope.
		unsafe { Ok(sys::AServiceManager_isDeclared(interface.as_ptr())) }
		}

		/// Retrieve all declared instances for a particular interface
		///
		/// For instance, if 'android.foo.IFoo/foo' is declared, and 'android.foo.IFoo'
		/// is passed here, then ["foo"] would be returned.
		pub fn get_declared_instances(interface: &str) -> Result<Vec<String>> {
		unsafe extern "C" fn callback(instance: const c_char, opaque: mut c_void) {
		// Safety: opaque was a mutable pointer created below from a Vec of
		// CString, and outlives this callback. The null handling here is just
		// to avoid the possibility of unwinding across C code if this crate is
		// ever compiled with panic=unwind.
		if let Some(instances) = unsafe { opaque.cast::<Vec<CString>>().as_mut() } {
		// Safety: instance is a valid null-terminated C string with a
		// lifetime at least as long as this function, and we immediately
		// copy it into an owned CString.
		unsafe {
		instances.push(CStr::from_ptr(instance).to_owned());
		}
		} else {
		eprintln!("Opaque pointer was null in get_declared_instances callback!");
		}
		}

		let interface = CString::new(interface).or(Err(StatusCode::UNEXPECTED_NULL))?;
		let mut instances: Vec<CString> = vec![];
		// Safety: `interface` and `instances` are borrowed for the length of this
		// call and both outlive the call. `interface` is guaranteed to be a valid
		// null-terminated C-style string.
		unsafe {
		sys::AServiceManager_forEachDeclaredInstance(
		interface.as_ptr(),
		&mut instances as mut _ as mut c_void,
		Some(callback),
		);
		}

		instances
		.into_iter()
		.map(CString::into_string)
		.collect::<std::result::Result<Vec<String>, _>>()
		.map_err(\|e\| {
		eprintln!("An interface instance name was not a valid UTF-8 string: {}", e);
		StatusCode::BAD_VALUE
		})
		}

		/// Safety: `SpIBinder` guarantees that `binder` always contains a valid pointer
		/// to an `AIBinder`, so we can trivially extract this pointer here.
		unsafe impl AsNative<sys::AIBinder> for SpIBinder {

libs/binder/rust/src/service.rs

0 → 100644

+230 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2024 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::binder::{AsNative, FromIBinder, Strong};
		use crate::error::{status_result, Result, StatusCode};
		use crate::proxy::SpIBinder;
		use crate::sys;

		use std::ffi::{c_void, CStr, CString};
		use std::os::raw::c_char;
		use std::sync::Mutex;

		/// Register a new service with the default service manager.
		///
		/// Registers the given binder object with the given identifier. If successful,
		/// this service can then be retrieved using that identifier.
		///
		/// This function will panic if the identifier contains a 0 byte (NUL).
		pub fn add_service(identifier: &str, mut binder: SpIBinder) -> Result<()> {
		let instance = CString::new(identifier).unwrap();
		let status =
		// Safety: `AServiceManager_addService` expects valid `AIBinder` and C
		// string pointers. Caller retains ownership of both pointers.
		// `AServiceManager_addService` creates a new strong reference and copies
		// the string, so both pointers need only be valid until the call returns.
		unsafe { sys::AServiceManager_addService(binder.as_native_mut(), instance.as_ptr()) };
		status_result(status)
		}

		/// Register a dynamic service via the LazyServiceRegistrar.
		///
		/// Registers the given binder object with the given identifier. If successful,
		/// this service can then be retrieved using that identifier. The service process
		/// will be shut down once all registered services are no longer in use.
		///
		/// If any service in the process is registered as lazy, all should be, otherwise
		/// the process may be shut down while a service is in use.
		///
		/// This function will panic if the identifier contains a 0 byte (NUL).
		pub fn register_lazy_service(identifier: &str, mut binder: SpIBinder) -> Result<()> {
		let instance = CString::new(identifier).unwrap();
		// Safety: `AServiceManager_registerLazyService` expects valid `AIBinder` and C
		// string pointers. Caller retains ownership of both
		// pointers. `AServiceManager_registerLazyService` creates a new strong reference
		// and copies the string, so both pointers need only be valid until the
		// call returns.
		let status = unsafe {
		sys::AServiceManager_registerLazyService(binder.as_native_mut(), instance.as_ptr())
		};
		status_result(status)
		}

		/// Prevent a process which registers lazy services from being shut down even when none
		/// of the services is in use.
		///
		/// If persist is true then shut down will be blocked until this function is called again with
		/// persist false. If this is to be the initial state, call this function before calling
		/// register_lazy_service.
		///
		/// Consider using [`LazyServiceGuard`] rather than calling this directly.
		pub fn force_lazy_services_persist(persist: bool) {
		// Safety: No borrowing or transfer of ownership occurs here.
		unsafe { sys::AServiceManager_forceLazyServicesPersist(persist) }
		}

		/// An RAII object to ensure a process which registers lazy services is not killed. During the
		/// lifetime of any of these objects the service manager will not kill the process even if none
		/// of its lazy services are in use.
		#[must_use]
		#[derive(Debug)]
		pub struct LazyServiceGuard {
		// Prevent construction outside this module.
		_private: (),
		}

		// Count of how many LazyServiceGuard objects are in existence.
		static GUARD_COUNT: Mutex<u64> = Mutex::new(0);

		impl LazyServiceGuard {
		/// Create a new LazyServiceGuard to prevent the service manager prematurely killing this
		/// process.
		pub fn new() -> Self {
		let mut count = GUARD_COUNT.lock().unwrap();
		*count += 1;
		if *count == 1 {
		// It's important that we make this call with the mutex held, to make sure
		// that multiple calls (e.g. if the count goes 1 -> 0 -> 1) are correctly
		// sequenced. (That also means we can't just use an AtomicU64.)
		force_lazy_services_persist(true);
		}
		Self { _private: () }
		}
		}

		impl Drop for LazyServiceGuard {
		fn drop(&mut self) {
		let mut count = GUARD_COUNT.lock().unwrap();
		*count -= 1;
		if *count == 0 {
		force_lazy_services_persist(false);
		}
		}
		}

		impl Clone for LazyServiceGuard {
		fn clone(&self) -> Self {
		Self::new()
		}
		}

		impl Default for LazyServiceGuard {
		fn default() -> Self {
		Self::new()
		}
		}

		/// Determine whether the current thread is currently executing an incoming
		/// transaction.
		pub fn is_handling_transaction() -> bool {
		// Safety: This method is always safe to call.
		unsafe { sys::AIBinder_isHandlingTransaction() }
		}

		fn interface_cast<T: FromIBinder + ?Sized>(service: Option<SpIBinder>) -> Result<Strong<T>> {
		if let Some(service) = service {
		FromIBinder::try_from(service)
		} else {
		Err(StatusCode::NAME_NOT_FOUND)
		}
		}

		/// Retrieve an existing service, blocking for a few seconds if it doesn't yet
		/// exist.
		pub fn get_service(name: &str) -> Option<SpIBinder> {
		let name = CString::new(name).ok()?;
		// Safety: `AServiceManager_getService` returns either a null pointer or a
		// valid pointer to an owned `AIBinder`. Either of these values is safe to
		// pass to `SpIBinder::from_raw`.
		unsafe { SpIBinder::from_raw(sys::AServiceManager_getService(name.as_ptr())) }
		}

		/// Retrieve an existing service, or start it if it is configured as a dynamic
		/// service and isn't yet started.
		pub fn wait_for_service(name: &str) -> Option<SpIBinder> {
		let name = CString::new(name).ok()?;
		// Safety: `AServiceManager_waitforService` returns either a null pointer or
		// a valid pointer to an owned `AIBinder`. Either of these values is safe to
		// pass to `SpIBinder::from_raw`.
		unsafe { SpIBinder::from_raw(sys::AServiceManager_waitForService(name.as_ptr())) }
		}

		/// Retrieve an existing service for a particular interface, blocking for a few
		/// seconds if it doesn't yet exist.
		pub fn get_interface<T: FromIBinder + ?Sized>(name: &str) -> Result<Strong<T>> {
		interface_cast(get_service(name))
		}

		/// Retrieve an existing service for a particular interface, or start it if it
		/// is configured as a dynamic service and isn't yet started.
		pub fn wait_for_interface<T: FromIBinder + ?Sized>(name: &str) -> Result<Strong<T>> {
		interface_cast(wait_for_service(name))
		}

		/// Check if a service is declared (e.g. in a VINTF manifest)
		pub fn is_declared(interface: &str) -> Result<bool> {
		let interface = CString::new(interface).or(Err(StatusCode::UNEXPECTED_NULL))?;

		// Safety: `interface` is a valid null-terminated C-style string and is only
		// borrowed for the lifetime of the call. The `interface` local outlives
		// this call as it lives for the function scope.
		unsafe { Ok(sys::AServiceManager_isDeclared(interface.as_ptr())) }
		}

		/// Retrieve all declared instances for a particular interface
		///
		/// For instance, if 'android.foo.IFoo/foo' is declared, and 'android.foo.IFoo'
		/// is passed here, then ["foo"] would be returned.
		pub fn get_declared_instances(interface: &str) -> Result<Vec<String>> {
		unsafe extern "C" fn callback(instance: const c_char, opaque: mut c_void) {
		// Safety: opaque was a mutable pointer created below from a Vec of
		// CString, and outlives this callback. The null handling here is just
		// to avoid the possibility of unwinding across C code if this crate is
		// ever compiled with panic=unwind.
		if let Some(instances) = unsafe { opaque.cast::<Vec<CString>>().as_mut() } {
		// Safety: instance is a valid null-terminated C string with a
		// lifetime at least as long as this function, and we immediately
		// copy it into an owned CString.
		unsafe {
		instances.push(CStr::from_ptr(instance).to_owned());
		}
		} else {
		eprintln!("Opaque pointer was null in get_declared_instances callback!");
		}
		}

		let interface = CString::new(interface).or(Err(StatusCode::UNEXPECTED_NULL))?;
		let mut instances: Vec<CString> = vec![];
		// Safety: `interface` and `instances` are borrowed for the length of this
		// call and both outlive the call. `interface` is guaranteed to be a valid
		// null-terminated C-style string.
		unsafe {
		sys::AServiceManager_forEachDeclaredInstance(
		interface.as_ptr(),
		&mut instances as mut _ as mut c_void,
		Some(callback),
		);
		}

		instances
		.into_iter()
		.map(CString::into_string)
		.collect::<std::result::Result<Vec<String>, _>>()
		.map_err(\|e\| {
		eprintln!("An interface instance name was not a valid UTF-8 string: {}", e);
		StatusCode::BAD_VALUE
		})
		}