Stephen Crane | 2a3c250 | 2020-06-16 17:48:35 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2020 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | //! Rust API for interacting with a remote binder service. |
| 18 | |
| 19 | use crate::binder::{ |
| 20 | AsNative, FromIBinder, IBinder, Interface, InterfaceClass, TransactionCode, TransactionFlags, |
| 21 | }; |
| 22 | use crate::error::{status_result, Result, StatusCode}; |
| 23 | use crate::parcel::{ |
| 24 | Deserialize, DeserializeArray, DeserializeOption, Parcel, Serialize, SerializeArray, |
| 25 | SerializeOption, |
| 26 | }; |
| 27 | use crate::sys; |
| 28 | |
| 29 | use std::convert::TryInto; |
| 30 | use std::ffi::{c_void, CString}; |
Andrei Homescu | 2e3c147 | 2020-08-11 16:35:40 -0700 | [diff] [blame] | 31 | use std::fmt; |
Stephen Crane | 2a3c250 | 2020-06-16 17:48:35 -0700 | [diff] [blame] | 32 | use std::os::unix::io::AsRawFd; |
| 33 | use std::ptr; |
| 34 | |
| 35 | /// A strong reference to a Binder remote object. |
| 36 | /// |
| 37 | /// This struct encapsulates the generic C++ `sp<IBinder>` class. This wrapper |
| 38 | /// is untyped; typed interface access is implemented by the AIDL compiler. |
| 39 | pub struct SpIBinder(*mut sys::AIBinder); |
| 40 | |
Andrei Homescu | 2e3c147 | 2020-08-11 16:35:40 -0700 | [diff] [blame] | 41 | impl fmt::Debug for SpIBinder { |
| 42 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| 43 | f.pad("SpIBinder") |
| 44 | } |
| 45 | } |
| 46 | |
Stephen Crane | 2a3c250 | 2020-06-16 17:48:35 -0700 | [diff] [blame] | 47 | /// # Safety |
| 48 | /// |
| 49 | /// An `SpIBinder` is a handle to a C++ IBinder, which is thread-safe |
| 50 | unsafe impl Send for SpIBinder {} |
| 51 | |
| 52 | impl SpIBinder { |
| 53 | /// Create an `SpIBinder` wrapper object from a raw `AIBinder` pointer. |
| 54 | /// |
| 55 | /// # Safety |
| 56 | /// |
| 57 | /// This constructor is safe iff `ptr` is a null pointer or a valid pointer |
| 58 | /// to an `AIBinder`. |
| 59 | /// |
| 60 | /// In the non-null case, this method conceptually takes ownership of a strong |
| 61 | /// reference to the object, so `AIBinder_incStrong` must have been called |
| 62 | /// on the pointer before passing it to this constructor. This is generally |
| 63 | /// done by Binder NDK methods that return an `AIBinder`, but care should be |
| 64 | /// taken to ensure this invariant. |
| 65 | /// |
| 66 | /// All `SpIBinder` objects that are constructed will hold a valid pointer |
| 67 | /// to an `AIBinder`, which will remain valid for the entire lifetime of the |
| 68 | /// `SpIBinder` (we keep a strong reference, and only decrement on drop). |
| 69 | pub(crate) unsafe fn from_raw(ptr: *mut sys::AIBinder) -> Option<Self> { |
| 70 | ptr.as_mut().map(|p| Self(p)) |
| 71 | } |
| 72 | |
| 73 | /// Return true if this binder object is hosted in a different process than |
| 74 | /// the current one. |
| 75 | pub fn is_remote(&self) -> bool { |
| 76 | unsafe { |
| 77 | // Safety: `SpIBinder` guarantees that it always contains a valid |
| 78 | // `AIBinder` pointer. |
| 79 | sys::AIBinder_isRemote(self.as_native()) |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | /// Try to convert this Binder object into a trait object for the given |
| 84 | /// Binder interface. |
| 85 | /// |
| 86 | /// If this object does not implement the expected interface, the error |
| 87 | /// `StatusCode::BAD_TYPE` is returned. |
| 88 | pub fn into_interface<I: FromIBinder + ?Sized>(self) -> Result<Box<I>> { |
| 89 | FromIBinder::try_from(self) |
| 90 | } |
| 91 | |
| 92 | /// Return the interface class of this binder object, if associated with |
| 93 | /// one. |
Matthew Maurer | f6b9ad9 | 2020-12-03 19:27:25 +0000 | [diff] [blame^] | 94 | pub(crate) fn get_class(&mut self) -> Option<InterfaceClass> { |
Stephen Crane | 2a3c250 | 2020-06-16 17:48:35 -0700 | [diff] [blame] | 95 | unsafe { |
| 96 | // Safety: `SpIBinder` guarantees that it always contains a valid |
| 97 | // `AIBinder` pointer. `AIBinder_getClass` returns either a null |
| 98 | // pointer or a valid pointer to an `AIBinder_Class`. After mapping |
| 99 | // null to None, we can safely construct an `InterfaceClass` if the |
| 100 | // pointer was non-null. |
| 101 | let class = sys::AIBinder_getClass(self.as_native_mut()); |
| 102 | class.as_ref().map(|p| InterfaceClass::from_ptr(p)) |
| 103 | } |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | /// An object that can be associate with an [`InterfaceClass`]. |
| 108 | pub trait AssociateClass { |
| 109 | /// Check if this object is a valid object for the given interface class |
| 110 | /// `I`. |
| 111 | /// |
| 112 | /// Returns `Some(self)` if this is a valid instance of the interface, and |
| 113 | /// `None` otherwise. |
| 114 | /// |
| 115 | /// Classes constructed by `InterfaceClass` are unique per type, so |
| 116 | /// repeatedly calling this method for the same `InterfaceClass` is allowed. |
| 117 | fn associate_class(&mut self, class: InterfaceClass) -> bool; |
| 118 | } |
| 119 | |
| 120 | impl AssociateClass for SpIBinder { |
| 121 | fn associate_class(&mut self, class: InterfaceClass) -> bool { |
| 122 | unsafe { |
| 123 | // Safety: `SpIBinder` guarantees that it always contains a valid |
| 124 | // `AIBinder` pointer. An `InterfaceClass` can always be converted |
| 125 | // into a valid `AIBinder_Class` pointer, so these parameters are |
| 126 | // always safe. |
| 127 | sys::AIBinder_associateClass(self.as_native_mut(), class.into()) |
| 128 | } |
| 129 | } |
| 130 | } |
| 131 | |
Stephen Crane | 994a0f0 | 2020-08-11 14:47:29 -0700 | [diff] [blame] | 132 | impl PartialEq for SpIBinder { |
| 133 | fn eq(&self, other: &Self) -> bool { |
| 134 | ptr::eq(self.0, other.0) |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | impl Eq for SpIBinder {} |
| 139 | |
Stephen Crane | 2a3c250 | 2020-06-16 17:48:35 -0700 | [diff] [blame] | 140 | impl Clone for SpIBinder { |
| 141 | fn clone(&self) -> Self { |
| 142 | unsafe { |
| 143 | // Safety: Cloning a strong reference must increment the reference |
| 144 | // count. We are guaranteed by the `SpIBinder` constructor |
| 145 | // invariants that `self.0` is always a valid `AIBinder` pointer. |
| 146 | sys::AIBinder_incStrong(self.0); |
| 147 | } |
| 148 | Self(self.0) |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | impl Drop for SpIBinder { |
| 153 | // We hold a strong reference to the IBinder in SpIBinder and need to give up |
| 154 | // this reference on drop. |
| 155 | fn drop(&mut self) { |
| 156 | unsafe { |
| 157 | // Safety: SpIBinder always holds a valid `AIBinder` pointer, so we |
| 158 | // know this pointer is safe to pass to `AIBinder_decStrong` here. |
| 159 | sys::AIBinder_decStrong(self.as_native_mut()); |
| 160 | } |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | impl<T: AsNative<sys::AIBinder>> IBinder for T { |
| 165 | /// Perform a binder transaction |
| 166 | fn transact<F: FnOnce(&mut Parcel) -> Result<()>>( |
| 167 | &self, |
| 168 | code: TransactionCode, |
| 169 | flags: TransactionFlags, |
| 170 | input_callback: F, |
| 171 | ) -> Result<Parcel> { |
| 172 | let mut input = ptr::null_mut(); |
| 173 | let status = unsafe { |
| 174 | // Safety: `SpIBinder` guarantees that `self` always contains a |
| 175 | // valid pointer to an `AIBinder`. It is safe to cast from an |
| 176 | // immutable pointer to a mutable pointer here, because |
| 177 | // `AIBinder_prepareTransaction` only calls immutable `AIBinder` |
| 178 | // methods but the parameter is unfortunately not marked as const. |
| 179 | // |
| 180 | // After the call, input will be either a valid, owned `AParcel` |
| 181 | // pointer, or null. |
| 182 | sys::AIBinder_prepareTransaction(self.as_native() as *mut sys::AIBinder, &mut input) |
| 183 | }; |
| 184 | status_result(status)?; |
| 185 | let mut input = unsafe { |
| 186 | // Safety: At this point, `input` is either a valid, owned `AParcel` |
| 187 | // pointer, or null. `Parcel::owned` safely handles both cases, |
| 188 | // taking ownership of the parcel. |
| 189 | Parcel::owned(input).ok_or(StatusCode::UNEXPECTED_NULL)? |
| 190 | }; |
| 191 | input_callback(&mut input)?; |
| 192 | let mut reply = ptr::null_mut(); |
| 193 | let status = unsafe { |
| 194 | // Safety: `SpIBinder` guarantees that `self` always contains a |
| 195 | // valid pointer to an `AIBinder`. Although `IBinder::transact` is |
| 196 | // not a const method, it is still safe to cast our immutable |
| 197 | // pointer to mutable for the call. First, `IBinder::transact` is |
| 198 | // thread-safe, so concurrency is not an issue. The only way that |
| 199 | // `transact` can affect any visible, mutable state in the current |
| 200 | // process is by calling `onTransact` for a local service. However, |
| 201 | // in order for transactions to be thread-safe, this method must |
| 202 | // dynamically lock its data before modifying it. We enforce this |
| 203 | // property in Rust by requiring `Sync` for remotable objects and |
| 204 | // only providing `on_transact` with an immutable reference to |
| 205 | // `self`. |
| 206 | // |
| 207 | // This call takes ownership of the `input` parcel pointer, and |
| 208 | // passes ownership of the `reply` out parameter to its caller. It |
| 209 | // does not affect ownership of the `binder` parameter. |
| 210 | sys::AIBinder_transact( |
| 211 | self.as_native() as *mut sys::AIBinder, |
| 212 | code, |
| 213 | &mut input.into_raw(), |
| 214 | &mut reply, |
| 215 | flags, |
| 216 | ) |
| 217 | }; |
| 218 | status_result(status)?; |
| 219 | |
| 220 | unsafe { |
| 221 | // Safety: `reply` is either a valid `AParcel` pointer or null |
| 222 | // after the call to `AIBinder_transact` above, so we can |
| 223 | // construct a `Parcel` out of it. `AIBinder_transact` passes |
| 224 | // ownership of the `reply` parcel to Rust, so we need to |
| 225 | // construct an owned variant. `Parcel::owned` takes ownership |
| 226 | // of the parcel pointer. |
| 227 | Parcel::owned(reply).ok_or(StatusCode::UNEXPECTED_NULL) |
| 228 | } |
| 229 | } |
| 230 | |
| 231 | fn is_binder_alive(&self) -> bool { |
| 232 | unsafe { |
| 233 | // Safety: `SpIBinder` guarantees that `self` always contains a |
| 234 | // valid pointer to an `AIBinder`. |
| 235 | // |
| 236 | // This call does not affect ownership of its pointer parameter. |
| 237 | sys::AIBinder_isAlive(self.as_native()) |
| 238 | } |
| 239 | } |
| 240 | |
| 241 | fn ping_binder(&mut self) -> Result<()> { |
| 242 | let status = unsafe { |
| 243 | // Safety: `SpIBinder` guarantees that `self` always contains a |
| 244 | // valid pointer to an `AIBinder`. |
| 245 | // |
| 246 | // This call does not affect ownership of its pointer parameter. |
| 247 | sys::AIBinder_ping(self.as_native_mut()) |
| 248 | }; |
| 249 | status_result(status) |
| 250 | } |
| 251 | |
Janis Danisevskis | 798a09a | 2020-08-18 08:35:38 -0700 | [diff] [blame] | 252 | fn set_requesting_sid(&mut self, enable: bool) { |
| 253 | unsafe { |
| 254 | sys::AIBinder_setRequestingSid(self.as_native_mut(), enable) |
| 255 | }; |
| 256 | } |
| 257 | |
Stephen Crane | 2a3c250 | 2020-06-16 17:48:35 -0700 | [diff] [blame] | 258 | fn dump<F: AsRawFd>(&mut self, fp: &F, args: &[&str]) -> Result<()> { |
| 259 | let args: Vec<_> = args.iter().map(|a| CString::new(*a).unwrap()).collect(); |
| 260 | let mut arg_ptrs: Vec<_> = args.iter().map(|a| a.as_ptr()).collect(); |
| 261 | let status = unsafe { |
| 262 | // Safety: `SpIBinder` guarantees that `self` always contains a |
| 263 | // valid pointer to an `AIBinder`. `AsRawFd` guarantees that the |
| 264 | // file descriptor parameter is always be a valid open file. The |
| 265 | // `args` pointer parameter is a valid pointer to an array of C |
| 266 | // strings that will outlive the call since `args` lives for the |
| 267 | // whole function scope. |
| 268 | // |
| 269 | // This call does not affect ownership of its binder pointer |
| 270 | // parameter and does not take ownership of the file or args array |
| 271 | // parameters. |
| 272 | sys::AIBinder_dump( |
| 273 | self.as_native_mut(), |
| 274 | fp.as_raw_fd(), |
| 275 | arg_ptrs.as_mut_ptr(), |
| 276 | arg_ptrs.len().try_into().unwrap(), |
| 277 | ) |
| 278 | }; |
| 279 | status_result(status) |
| 280 | } |
| 281 | |
| 282 | fn get_extension(&mut self) -> Result<Option<SpIBinder>> { |
| 283 | let mut out = ptr::null_mut(); |
| 284 | let status = unsafe { |
| 285 | // Safety: `SpIBinder` guarantees that `self` always contains a |
| 286 | // valid pointer to an `AIBinder`. After this call, the `out` |
| 287 | // parameter will be either null, or a valid pointer to an |
| 288 | // `AIBinder`. |
| 289 | // |
| 290 | // This call passes ownership of the out pointer to its caller |
| 291 | // (assuming it is set to a non-null value). |
| 292 | sys::AIBinder_getExtension(self.as_native_mut(), &mut out) |
| 293 | }; |
| 294 | let ibinder = unsafe { |
| 295 | // Safety: The call above guarantees that `out` is either null or a |
| 296 | // valid, owned pointer to an `AIBinder`, both of which are safe to |
| 297 | // pass to `SpIBinder::from_raw`. |
| 298 | SpIBinder::from_raw(out) |
| 299 | }; |
| 300 | |
| 301 | status_result(status)?; |
| 302 | Ok(ibinder) |
| 303 | } |
| 304 | |
| 305 | fn link_to_death(&mut self, recipient: &mut DeathRecipient) -> Result<()> { |
| 306 | status_result(unsafe { |
| 307 | // Safety: `SpIBinder` guarantees that `self` always contains a |
| 308 | // valid pointer to an `AIBinder`. `recipient` can always be |
| 309 | // converted into a valid pointer to an |
| 310 | // `AIBinder_DeatRecipient`. Any value is safe to pass as the |
| 311 | // cookie, although we depend on this value being set by |
| 312 | // `get_cookie` when the death recipient callback is called. |
| 313 | sys::AIBinder_linkToDeath( |
| 314 | self.as_native_mut(), |
| 315 | recipient.as_native_mut(), |
| 316 | recipient.get_cookie(), |
| 317 | ) |
| 318 | }) |
| 319 | } |
| 320 | |
| 321 | fn unlink_to_death(&mut self, recipient: &mut DeathRecipient) -> Result<()> { |
| 322 | status_result(unsafe { |
| 323 | // Safety: `SpIBinder` guarantees that `self` always contains a |
| 324 | // valid pointer to an `AIBinder`. `recipient` can always be |
| 325 | // converted into a valid pointer to an |
| 326 | // `AIBinder_DeatRecipient`. Any value is safe to pass as the |
| 327 | // cookie, although we depend on this value being set by |
| 328 | // `get_cookie` when the death recipient callback is called. |
| 329 | sys::AIBinder_unlinkToDeath( |
| 330 | self.as_native_mut(), |
| 331 | recipient.as_native_mut(), |
| 332 | recipient.get_cookie(), |
| 333 | ) |
| 334 | }) |
| 335 | } |
| 336 | } |
| 337 | |
| 338 | impl Serialize for SpIBinder { |
| 339 | fn serialize(&self, parcel: &mut Parcel) -> Result<()> { |
| 340 | parcel.write_binder(Some(self)) |
| 341 | } |
| 342 | } |
| 343 | |
| 344 | impl SerializeOption for SpIBinder { |
| 345 | fn serialize_option(this: Option<&Self>, parcel: &mut Parcel) -> Result<()> { |
| 346 | parcel.write_binder(this) |
| 347 | } |
| 348 | } |
| 349 | |
| 350 | impl SerializeArray for SpIBinder {} |
| 351 | impl SerializeArray for Option<&SpIBinder> {} |
| 352 | |
| 353 | impl Deserialize for SpIBinder { |
| 354 | fn deserialize(parcel: &Parcel) -> Result<SpIBinder> { |
Andrei Homescu | 3281437 | 2020-08-20 15:36:08 -0700 | [diff] [blame] | 355 | parcel |
| 356 | .read_binder() |
| 357 | .transpose() |
| 358 | .unwrap_or(Err(StatusCode::UNEXPECTED_NULL)) |
Stephen Crane | 2a3c250 | 2020-06-16 17:48:35 -0700 | [diff] [blame] | 359 | } |
| 360 | } |
| 361 | |
| 362 | impl DeserializeOption for SpIBinder { |
| 363 | fn deserialize_option(parcel: &Parcel) -> Result<Option<SpIBinder>> { |
| 364 | parcel.read_binder() |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | impl DeserializeArray for SpIBinder {} |
| 369 | impl DeserializeArray for Option<SpIBinder> {} |
| 370 | |
| 371 | /// A weak reference to a Binder remote object. |
| 372 | /// |
| 373 | /// This struct encapsulates the C++ `wp<IBinder>` class. However, this wrapper |
| 374 | /// is untyped, so properly typed versions implementing a particular binder |
| 375 | /// interface should be crated with [`declare_binder_interface!`]. |
| 376 | pub struct WpIBinder(*mut sys::AIBinder_Weak); |
| 377 | |
| 378 | impl WpIBinder { |
| 379 | /// Create a new weak reference from an object that can be converted into a |
| 380 | /// raw `AIBinder` pointer. |
| 381 | pub fn new<B: AsNative<sys::AIBinder>>(binder: &mut B) -> WpIBinder { |
| 382 | let ptr = unsafe { |
| 383 | // Safety: `SpIBinder` guarantees that `binder` always contains a |
| 384 | // valid pointer to an `AIBinder`. |
| 385 | sys::AIBinder_Weak_new(binder.as_native_mut()) |
| 386 | }; |
| 387 | assert!(!ptr.is_null()); |
| 388 | Self(ptr) |
| 389 | } |
Stephen Crane | 994a0f0 | 2020-08-11 14:47:29 -0700 | [diff] [blame] | 390 | |
| 391 | /// Promote this weak reference to a strong reference to the binder object. |
| 392 | pub fn promote(&self) -> Option<SpIBinder> { |
| 393 | unsafe { |
| 394 | // Safety: `WpIBinder` always contains a valid weak reference, so we |
| 395 | // can pass this pointer to `AIBinder_Weak_promote`. Returns either |
| 396 | // null or an AIBinder owned by the caller, both of which are valid |
| 397 | // to pass to `SpIBinder::from_raw`. |
| 398 | let ptr = sys::AIBinder_Weak_promote(self.0); |
| 399 | SpIBinder::from_raw(ptr) |
| 400 | } |
| 401 | } |
Stephen Crane | 2a3c250 | 2020-06-16 17:48:35 -0700 | [diff] [blame] | 402 | } |
| 403 | |
| 404 | /// Rust wrapper around DeathRecipient objects. |
| 405 | #[repr(C)] |
| 406 | pub struct DeathRecipient { |
| 407 | recipient: *mut sys::AIBinder_DeathRecipient, |
| 408 | callback: Box<dyn Fn() + Send + 'static>, |
| 409 | } |
| 410 | |
| 411 | impl DeathRecipient { |
| 412 | /// Create a new death recipient that will call the given callback when its |
| 413 | /// associated object dies. |
| 414 | pub fn new<F>(callback: F) -> DeathRecipient |
| 415 | where |
| 416 | F: Fn() + Send + 'static, |
| 417 | { |
| 418 | let callback = Box::new(callback); |
| 419 | let recipient = unsafe { |
| 420 | // Safety: The function pointer is a valid death recipient callback. |
| 421 | // |
| 422 | // This call returns an owned `AIBinder_DeathRecipient` pointer |
| 423 | // which must be destroyed via `AIBinder_DeathRecipient_delete` when |
| 424 | // no longer needed. |
| 425 | sys::AIBinder_DeathRecipient_new(Some(Self::binder_died::<F>)) |
| 426 | }; |
| 427 | DeathRecipient { |
| 428 | recipient, |
| 429 | callback, |
| 430 | } |
| 431 | } |
| 432 | |
| 433 | /// Get the opaque cookie that identifies this death recipient. |
| 434 | /// |
| 435 | /// This cookie will be used to link and unlink this death recipient to a |
| 436 | /// binder object and will be passed to the `binder_died` callback as an |
| 437 | /// opaque userdata pointer. |
| 438 | fn get_cookie(&self) -> *mut c_void { |
| 439 | &*self.callback as *const _ as *mut c_void |
| 440 | } |
| 441 | |
| 442 | /// Callback invoked from C++ when the binder object dies. |
| 443 | /// |
| 444 | /// # Safety |
| 445 | /// |
| 446 | /// The `cookie` parameter must have been created with the `get_cookie` |
| 447 | /// method of this object. |
| 448 | unsafe extern "C" fn binder_died<F>(cookie: *mut c_void) |
| 449 | where |
| 450 | F: Fn() + Send + 'static, |
| 451 | { |
| 452 | let callback = (cookie as *mut F).as_ref().unwrap(); |
| 453 | callback(); |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | /// # Safety |
| 458 | /// |
| 459 | /// A `DeathRecipient` is always constructed with a valid raw pointer to an |
| 460 | /// `AIBinder_DeathRecipient`, so it is always type-safe to extract this |
| 461 | /// pointer. |
| 462 | unsafe impl AsNative<sys::AIBinder_DeathRecipient> for DeathRecipient { |
| 463 | fn as_native(&self) -> *const sys::AIBinder_DeathRecipient { |
| 464 | self.recipient |
| 465 | } |
| 466 | |
| 467 | fn as_native_mut(&mut self) -> *mut sys::AIBinder_DeathRecipient { |
| 468 | self.recipient |
| 469 | } |
| 470 | } |
| 471 | |
| 472 | impl Drop for DeathRecipient { |
| 473 | fn drop(&mut self) { |
| 474 | unsafe { |
| 475 | // Safety: `self.recipient` is always a valid, owned |
| 476 | // `AIBinder_DeathRecipient` pointer returned by |
| 477 | // `AIBinder_DeathRecipient_new` when `self` was created. This |
| 478 | // delete method can only be called once when `self` is dropped. |
| 479 | sys::AIBinder_DeathRecipient_delete(self.recipient); |
| 480 | } |
| 481 | } |
| 482 | } |
| 483 | |
| 484 | /// Generic interface to remote binder objects. |
| 485 | /// |
| 486 | /// Corresponds to the C++ `BpInterface` class. |
| 487 | pub trait Proxy: Sized + Interface { |
| 488 | /// The Binder interface descriptor string. |
| 489 | /// |
| 490 | /// This string is a unique identifier for a Binder interface, and should be |
| 491 | /// the same between all implementations of that interface. |
| 492 | fn get_descriptor() -> &'static str; |
| 493 | |
| 494 | /// Create a new interface from the given proxy, if it matches the expected |
| 495 | /// type of this interface. |
| 496 | fn from_binder(binder: SpIBinder) -> Result<Self>; |
| 497 | } |
| 498 | |
| 499 | /// # Safety |
| 500 | /// |
| 501 | /// This is a convenience method that wraps `AsNative` for `SpIBinder` to allow |
| 502 | /// invocation of `IBinder` methods directly from `Interface` objects. It shares |
| 503 | /// the same safety as the implementation for `SpIBinder`. |
| 504 | unsafe impl<T: Proxy> AsNative<sys::AIBinder> for T { |
| 505 | fn as_native(&self) -> *const sys::AIBinder { |
| 506 | self.as_binder().as_native() |
| 507 | } |
| 508 | |
| 509 | fn as_native_mut(&mut self) -> *mut sys::AIBinder { |
| 510 | self.as_binder().as_native_mut() |
| 511 | } |
| 512 | } |
| 513 | |
| 514 | /// Retrieve an existing service, blocking for a few seconds if it doesn't yet |
| 515 | /// exist. |
| 516 | pub fn get_service(name: &str) -> Option<SpIBinder> { |
| 517 | let name = CString::new(name).ok()?; |
| 518 | unsafe { |
| 519 | // Safety: `AServiceManager_getService` returns either a null pointer or |
| 520 | // a valid pointer to an owned `AIBinder`. Either of these values is |
| 521 | // safe to pass to `SpIBinder::from_raw`. |
| 522 | SpIBinder::from_raw(sys::AServiceManager_getService(name.as_ptr())) |
| 523 | } |
| 524 | } |
| 525 | |
| 526 | /// Retrieve an existing service for a particular interface, blocking for a few |
| 527 | /// seconds if it doesn't yet exist. |
| 528 | pub fn get_interface<T: FromIBinder + ?Sized>(name: &str) -> Result<Box<T>> { |
| 529 | let service = get_service(name); |
| 530 | match service { |
| 531 | Some(service) => FromIBinder::try_from(service), |
| 532 | None => Err(StatusCode::NAME_NOT_FOUND), |
| 533 | } |
| 534 | } |
| 535 | |
| 536 | /// # Safety |
| 537 | /// |
| 538 | /// `SpIBinder` guarantees that `binder` always contains a valid pointer to an |
| 539 | /// `AIBinder`, so we can trivially extract this pointer here. |
| 540 | unsafe impl AsNative<sys::AIBinder> for SpIBinder { |
| 541 | fn as_native(&self) -> *const sys::AIBinder { |
| 542 | self.0 |
| 543 | } |
| 544 | |
| 545 | fn as_native_mut(&mut self) -> *mut sys::AIBinder { |
| 546 | self.0 |
| 547 | } |
| 548 | } |