FILE
thread.rs
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linux-6.19.14/drivers/android/binder/thread.rs
1// SPDX-License-Identifier: GPL-2.0 2 3// Copyright (C) 2025 Google LLC. 4 5//! This module defines the `Thread` type, which represents a userspace thread that is using 6//! binder. 7//! 8//! The `Process` object stores all of the threads in an rb tree. 9 10use kernel::{ 11 bindings, 12 fs::{File, LocalFile}, 13 list::{AtomicTracker, List, ListArc, ListLinks, TryNewListArc}, 14 prelude::*, 15 security, 16 seq_file::SeqFile, 17 seq_print, 18 sync::poll::{PollCondVar, PollTable}, 19 sync::{Arc, SpinLock}, 20 task::Task, 21 types::ARef, 22 uaccess::UserSlice, 23 uapi, 24}; 25 26use crate::{ 27 allocation::{Allocation, AllocationView, BinderObject, BinderObjectRef, NewAllocation}, 28 defs::*, 29 error::BinderResult, 30 process::{GetWorkOrRegister, Process}, 31 ptr_align, 32 stats::GLOBAL_STATS, 33 transaction::Transaction, 34 BinderReturnWriter, DArc, DLArc, DTRWrap, DeliverCode, DeliverToRead, 35}; 36 37use core::{ 38 mem::size_of, 39 sync::atomic::{AtomicU32, Ordering}, 40}; 41 42fn is_aligned(value: usize, to: usize) -> bool { 43 value % to == 0 44} 45 46/// Stores the layout of the scatter-gather entries. This is used during the `translate_objects` 47/// call and is discarded when it returns. 48struct ScatterGatherState { 49 /// A struct that tracks the amount of unused buffer space. 50 unused_buffer_space: UnusedBufferSpace, 51 /// Scatter-gather entries to copy. 52 sg_entries: KVec<ScatterGatherEntry>, 53 /// Indexes into `sg_entries` corresponding to the last binder_buffer_object that 54 /// was processed and all of its ancestors. The array is in sorted order. 55 ancestors: KVec<usize>, 56} 57 58/// This entry specifies an additional buffer that should be copied using the scatter-gather 59/// mechanism. 60struct ScatterGatherEntry { 61 /// The index in the offset array of the BINDER_TYPE_PTR that this entry originates from. 62 obj_index: usize, 63 /// Offset in target buffer. 64 offset: usize, 65 /// User address in source buffer. 66 sender_uaddr: usize, 67 /// Number of bytes to copy. 68 length: usize, 69 /// The minimum offset of the next fixup in this buffer. 70 fixup_min_offset: usize, 71 /// The offsets within this buffer that contain pointers which should be translated. 72 pointer_fixups: KVec<PointerFixupEntry>, 73} 74 75/// This entry specifies that a fixup should happen at `target_offset` of the 76/// buffer. 77enum PointerFixupEntry { 78 /// A fixup for a `binder_buffer_object`. 79 Fixup { 80 /// The translated pointer to write. 81 pointer_value: u64, 82 /// The offset at which the value should be written. The offset is relative 83 /// to the original buffer. 84 target_offset: usize, 85 }, 86 /// A skip for a `binder_fd_array_object`. 87 Skip { 88 /// The number of bytes to skip. 89 skip: usize, 90 /// The offset at which the skip should happen. The offset is relative 91 /// to the original buffer. 92 target_offset: usize, 93 }, 94} 95 96/// Return type of `apply_and_validate_fixup_in_parent`. 97struct ParentFixupInfo { 98 /// The index of the parent buffer in `sg_entries`. 99 parent_sg_index: usize, 100 /// The number of ancestors of the buffer. 101 /// 102 /// The buffer is considered an ancestor of itself, so this is always at 103 /// least one. 104 num_ancestors: usize, 105 /// New value of `fixup_min_offset` if this fixup is applied. 106 new_min_offset: usize, 107 /// The offset of the fixup in the target buffer. 108 target_offset: usize, 109} 110 111impl ScatterGatherState { 112 /// Called when a `binder_buffer_object` or `binder_fd_array_object` tries 113 /// to access a region in its parent buffer. These accesses have various 114 /// restrictions, which this method verifies. 115 /// 116 /// The `parent_offset` and `length` arguments describe the offset and 117 /// length of the access in the parent buffer. 118 /// 119 /// # Detailed restrictions 120 /// 121 /// Obviously the fixup must be in-bounds for the parent buffer. 122 /// 123 /// For safety reasons, we only allow fixups inside a buffer to happen 124 /// at increasing offsets; additionally, we only allow fixup on the last 125 /// buffer object that was verified, or one of its parents. 126 /// 127 /// Example of what is allowed: 128 /// 129 /// A 130 /// B (parent = A, offset = 0) 131 /// C (parent = A, offset = 16) 132 /// D (parent = C, offset = 0) 133 /// E (parent = A, offset = 32) // min_offset is 16 (C.parent_offset) 134 /// 135 /// Examples of what is not allowed: 136 /// 137 /// Decreasing offsets within the same parent: 138 /// A 139 /// C (parent = A, offset = 16) 140 /// B (parent = A, offset = 0) // decreasing offset within A 141 /// 142 /// Arcerring to a parent that wasn't the last object or any of its parents: 143 /// A 144 /// B (parent = A, offset = 0) 145 /// C (parent = A, offset = 0) 146 /// C (parent = A, offset = 16) 147 /// D (parent = B, offset = 0) // B is not A or any of A's parents 148 fn validate_parent_fixup( 149 &self, 150 parent: usize, 151 parent_offset: usize, 152 length: usize, 153 ) -> Result<ParentFixupInfo> { 154 // Using `position` would also be correct, but `rposition` avoids 155 // quadratic running times. 156 let ancestors_i = self 157 .ancestors 158 .iter() 159 .copied() 160 .rposition(|sg_idx| self.sg_entries[sg_idx].obj_index == parent) 161 .ok_or(EINVAL)?; 162 let sg_idx = self.ancestors[ancestors_i]; 163 let sg_entry = match self.sg_entries.get(sg_idx) { 164 Some(sg_entry) => sg_entry, 165 None => { 166 pr_err!( 167 "self.ancestors[{}] is {}, but self.sg_entries.len() is {}", 168 ancestors_i, 169 sg_idx, 170 self.sg_entries.len() 171 ); 172 return Err(EINVAL); 173 } 174 }; 175 if sg_entry.fixup_min_offset > parent_offset { 176 pr_warn!( 177 "validate_parent_fixup: fixup_min_offset={}, parent_offset={}", 178 sg_entry.fixup_min_offset, 179 parent_offset 180 ); 181 return Err(EINVAL); 182 } 183 let new_min_offset = parent_offset.checked_add(length).ok_or(EINVAL)?; 184 if new_min_offset > sg_entry.length { 185 pr_warn!( 186 "validate_parent_fixup: new_min_offset={}, sg_entry.length={}", 187 new_min_offset, 188 sg_entry.length 189 ); 190 return Err(EINVAL); 191 } 192 let target_offset = sg_entry.offset.checked_add(parent_offset).ok_or(EINVAL)?; 193 // The `ancestors_i + 1` operation can't overflow since the output of the addition is at 194 // most `self.ancestors.len()`, which also fits in a usize. 195 Ok(ParentFixupInfo { 196 parent_sg_index: sg_idx, 197 num_ancestors: ancestors_i + 1, 198 new_min_offset, 199 target_offset, 200 }) 201 } 202} 203 204/// Keeps track of how much unused buffer space is left. The initial amount is the number of bytes 205/// requested by the user using the `buffers_size` field of `binder_transaction_data_sg`. Each time 206/// we translate an object of type `BINDER_TYPE_PTR`, some of the unused buffer space is consumed. 207struct UnusedBufferSpace { 208 /// The start of the remaining space. 209 offset: usize, 210 /// The end of the remaining space. 211 limit: usize, 212} 213impl UnusedBufferSpace { 214 /// Claim the next `size` bytes from the unused buffer space. The offset for the claimed chunk 215 /// into the buffer is returned. 216 fn claim_next(&mut self, size: usize) -> Result<usize> { 217 // We require every chunk to be aligned. 218 let size = ptr_align(size).ok_or(EINVAL)?; 219 let new_offset = self.offset.checked_add(size).ok_or(EINVAL)?; 220 221 if new_offset <= self.limit { 222 let offset = self.offset; 223 self.offset = new_offset; 224 Ok(offset) 225 } else { 226 Err(EINVAL) 227 } 228 } 229} 230 231pub(crate) enum PushWorkRes { 232 Ok, 233 FailedDead(DLArc<dyn DeliverToRead>), 234} 235 236impl PushWorkRes { 237 fn is_ok(&self) -> bool { 238 match self { 239 PushWorkRes::Ok => true, 240 PushWorkRes::FailedDead(_) => false, 241 } 242 } 243} 244 245/// The fields of `Thread` protected by the spinlock. 246struct InnerThread { 247 /// Determines the looper state of the thread. It is a bit-wise combination of the constants 248 /// prefixed with `LOOPER_`. 249 looper_flags: u32, 250 251 /// Determines whether the looper should return. 252 looper_need_return: bool, 253 254 /// Determines if thread is dead. 255 is_dead: bool, 256 257 /// Work item used to deliver error codes to the thread that started a transaction. Stored here 258 /// so that it can be reused. 259 reply_work: DArc<ThreadError>, 260 261 /// Work item used to deliver error codes to the current thread. Stored here so that it can be 262 /// reused. 263 return_work: DArc<ThreadError>, 264 265 /// Determines whether the work list below should be processed. When set to false, `work_list` 266 /// is treated as if it were empty. 267 process_work_list: bool, 268 /// List of work items to deliver to userspace. 269 work_list: List<DTRWrap<dyn DeliverToRead>>, 270 current_transaction: Option<DArc<Transaction>>, 271 272 /// Extended error information for this thread. 273 extended_error: ExtendedError, 274} 275 276const LOOPER_REGISTERED: u32 = 0x01; 277const LOOPER_ENTERED: u32 = 0x02; 278const LOOPER_EXITED: u32 = 0x04; 279const LOOPER_INVALID: u32 = 0x08; 280const LOOPER_WAITING: u32 = 0x10; 281const LOOPER_WAITING_PROC: u32 = 0x20; 282const LOOPER_POLL: u32 = 0x40; 283 284impl InnerThread { 285 fn new() -> Result<Self> { 286 fn next_err_id() -> u32 { 287 static EE_ID: AtomicU32 = AtomicU32::new(0); 288 EE_ID.fetch_add(1, Ordering::Relaxed) 289 } 290 291 Ok(Self { 292 looper_flags: 0, 293 looper_need_return: false, 294 is_dead: false, 295 process_work_list: false, 296 reply_work: ThreadError::try_new()?, 297 return_work: ThreadError::try_new()?, 298 work_list: List::new(), 299 current_transaction: None, 300 extended_error: ExtendedError::new(next_err_id(), BR_OK, 0), 301 }) 302 } 303 304 fn pop_work(&mut self) -> Option<DLArc<dyn DeliverToRead>> { 305 if !self.process_work_list { 306 return None; 307 } 308 309 let ret = self.work_list.pop_front(); 310 self.process_work_list = !self.work_list.is_empty(); 311 ret 312 } 313 314 fn push_work(&mut self, work: DLArc<dyn DeliverToRead>) -> PushWorkRes { 315 if self.is_dead { 316 PushWorkRes::FailedDead(work) 317 } else { 318 self.work_list.push_back(work); 319 self.process_work_list = true; 320 PushWorkRes::Ok 321 } 322 } 323 324 fn push_reply_work(&mut self, code: u32) { 325 if let Ok(work) = ListArc::try_from_arc(self.reply_work.clone()) { 326 work.set_error_code(code); 327 self.push_work(work); 328 } else { 329 pr_warn!("Thread reply work is already in use."); 330 } 331 } 332 333 fn push_return_work(&mut self, reply: u32) { 334 if let Ok(work) = ListArc::try_from_arc(self.return_work.clone()) { 335 work.set_error_code(reply); 336 self.push_work(work); 337 } else { 338 pr_warn!("Thread return work is already in use."); 339 } 340 } 341 342 /// Used to push work items that do not need to be processed immediately and can wait until the 343 /// thread gets another work item. 344 fn push_work_deferred(&mut self, work: DLArc<dyn DeliverToRead>) { 345 self.work_list.push_back(work); 346 } 347 348 /// Fetches the transaction this thread can reply to. If the thread has a pending transaction 349 /// (that it could respond to) but it has also issued a transaction, it must first wait for the 350 /// previously-issued transaction to complete. 351 /// 352 /// The `thread` parameter should be the thread containing this `ThreadInner`. 353 fn pop_transaction_to_reply(&mut self, thread: &Thread) -> Result<DArc<Transaction>> { 354 let transaction = self.current_transaction.take().ok_or(EINVAL)?; 355 if core::ptr::eq(thread, transaction.from.as_ref()) { 356 self.current_transaction = Some(transaction); 357 return Err(EINVAL); 358 } 359 // Find a new current transaction for this thread. 360 self.current_transaction = transaction.find_from(thread).cloned(); 361 Ok(transaction) 362 } 363 364 fn pop_transaction_replied(&mut self, transaction: &DArc<Transaction>) -> bool { 365 match self.current_transaction.take() { 366 None => false, 367 Some(old) => { 368 if !Arc::ptr_eq(transaction, &old) { 369 self.current_transaction = Some(old); 370 return false; 371 } 372 self.current_transaction = old.clone_next(); 373 true 374 } 375 } 376 } 377 378 fn looper_enter(&mut self) { 379 self.looper_flags |= LOOPER_ENTERED; 380 if self.looper_flags & LOOPER_REGISTERED != 0 { 381 self.looper_flags |= LOOPER_INVALID; 382 } 383 } 384 385 fn looper_register(&mut self, valid: bool) { 386 self.looper_flags |= LOOPER_REGISTERED; 387 if !valid || self.looper_flags & LOOPER_ENTERED != 0 { 388 self.looper_flags |= LOOPER_INVALID; 389 } 390 } 391 392 fn looper_exit(&mut self) { 393 self.looper_flags |= LOOPER_EXITED; 394 } 395 396 /// Determines whether the thread is part of a pool, i.e., if it is a looper. 397 fn is_looper(&self) -> bool { 398 self.looper_flags & (LOOPER_ENTERED | LOOPER_REGISTERED) != 0 399 } 400 401 /// Determines whether the thread should attempt to fetch work items from the process queue. 402 /// This is generally case when the thread is registered as a looper and not part of a 403 /// transaction stack. But if there is local work, we want to return to userspace before we 404 /// deliver any remote work. 405 fn should_use_process_work_queue(&self) -> bool { 406 self.current_transaction.is_none() && !self.process_work_list && self.is_looper() 407 } 408 409 fn poll(&mut self) -> u32 { 410 self.looper_flags |= LOOPER_POLL; 411 if self.process_work_list || self.looper_need_return { 412 bindings::POLLIN 413 } else { 414 0 415 } 416 } 417} 418 419/// This represents a thread that's used with binder. 420#[pin_data] 421pub(crate) struct Thread { 422 pub(crate) id: i32, 423 pub(crate) process: Arc<Process>, 424 pub(crate) task: ARef<Task>, 425 #[pin] 426 inner: SpinLock<InnerThread>, 427 #[pin] 428 work_condvar: PollCondVar, 429 /// Used to insert this thread into the process' `ready_threads` list. 430 /// 431 /// INVARIANT: May never be used for any other list than the `self.process.ready_threads`. 432 #[pin] 433 links: ListLinks, 434 #[pin] 435 links_track: AtomicTracker, 436} 437 438kernel::list::impl_list_arc_safe! { 439 impl ListArcSafe<0> for Thread { 440 tracked_by links_track: AtomicTracker; 441 } 442} 443kernel::list::impl_list_item! { 444 impl ListItem<0> for Thread { 445 using ListLinks { self.links }; 446 } 447} 448 449impl Thread { 450 pub(crate) fn new(id: i32, process: Arc<Process>) -> Result<Arc<Self>> { 451 let inner = InnerThread::new()?; 452 453 Arc::pin_init( 454 try_pin_init!(Thread { 455 id, 456 process, 457 task: ARef::from(&**kernel::current!()), 458 inner <- kernel::new_spinlock!(inner, "Thread::inner"), 459 work_condvar <- kernel::new_poll_condvar!("Thread::work_condvar"), 460 links <- ListLinks::new(), 461 links_track <- AtomicTracker::new(), 462 }), 463 GFP_KERNEL, 464 ) 465 } 466 467 #[inline(never)] 468 pub(crate) fn debug_print(self: &Arc<Self>, m: &SeqFile, print_all: bool) -> Result<()> { 469 let inner = self.inner.lock(); 470 471 if print_all || inner.current_transaction.is_some() || !inner.work_list.is_empty() { 472 seq_print!( 473 m, 474 " thread {}: l {:02x} need_return {}\n", 475 self.id, 476 inner.looper_flags, 477 inner.looper_need_return, 478 ); 479 } 480 481 let mut t_opt = inner.current_transaction.as_ref(); 482 while let Some(t) = t_opt { 483 if Arc::ptr_eq(&t.from, self) { 484 t.debug_print_inner(m, " outgoing transaction "); 485 t_opt = t.from_parent.as_ref(); 486 } else if Arc::ptr_eq(&t.to, &self.process) { 487 t.debug_print_inner(m, " incoming transaction "); 488 t_opt = t.find_from(self); 489 } else { 490 t.debug_print_inner(m, " bad transaction "); 491 t_opt = None; 492 } 493 } 494 495 for work in &inner.work_list { 496 work.debug_print(m, " ", " pending transaction ")?; 497 } 498 Ok(()) 499 } 500 501 pub(crate) fn get_extended_error(&self, data: UserSlice) -> Result { 502 let mut writer = data.writer(); 503 let ee = self.inner.lock().extended_error; 504 writer.write(&ee)?; 505 Ok(()) 506 } 507 508 pub(crate) fn set_current_transaction(&self, transaction: DArc<Transaction>) { 509 self.inner.lock().current_transaction = Some(transaction); 510 } 511 512 pub(crate) fn has_current_transaction(&self) -> bool { 513 self.inner.lock().current_transaction.is_some() 514 } 515 516 /// Attempts to fetch a work item from the thread-local queue. The behaviour if the queue is 517 /// empty depends on `wait`: if it is true, the function waits for some work to be queued (or a 518 /// signal); otherwise it returns indicating that none is available. 519 fn get_work_local(self: &Arc<Self>, wait: bool) -> Result<Option<DLArc<dyn DeliverToRead>>> { 520 { 521 let mut inner = self.inner.lock(); 522 if inner.looper_need_return { 523 return Ok(inner.pop_work()); 524 } 525 } 526 527 // Try once if the caller does not want to wait. 528 if !wait { 529 return self.inner.lock().pop_work().ok_or(EAGAIN).map(Some); 530 } 531 532 // Loop waiting only on the local queue (i.e., not registering with the process queue). 533 let mut inner = self.inner.lock(); 534 loop { 535 if let Some(work) = inner.pop_work() { 536 return Ok(Some(work)); 537 } 538 539 inner.looper_flags |= LOOPER_WAITING; 540 let signal_pending = self.work_condvar.wait_interruptible_freezable(&mut inner); 541 inner.looper_flags &= !LOOPER_WAITING; 542 543 if signal_pending { 544 return Err(EINTR); 545 } 546 if inner.looper_need_return { 547 return Ok(None); 548 } 549 } 550 } 551 552 /// Attempts to fetch a work item from the thread-local queue, falling back to the process-wide 553 /// queue if none is available locally. 554 /// 555 /// This must only be called when the thread is not participating in a transaction chain. If it 556 /// is, the local version (`get_work_local`) should be used instead. 557 fn get_work(self: &Arc<Self>, wait: bool) -> Result<Option<DLArc<dyn DeliverToRead>>> { 558 // Try to get work from the thread's work queue, using only a local lock. 559 { 560 let mut inner = self.inner.lock(); 561 if let Some(work) = inner.pop_work() { 562 return Ok(Some(work)); 563 } 564 if inner.looper_need_return { 565 drop(inner); 566 return Ok(self.process.get_work()); 567 } 568 } 569 570 // If the caller doesn't want to wait, try to grab work from the process queue. 571 // 572 // We know nothing will have been queued directly to the thread queue because it is not in 573 // a transaction and it is not in the process' ready list. 574 if !wait { 575 return self.process.get_work().ok_or(EAGAIN).map(Some); 576 } 577 578 // Get work from the process queue. If none is available, atomically register as ready. 579 let reg = match self.process.get_work_or_register(self) { 580 GetWorkOrRegister::Work(work) => return Ok(Some(work)), 581 GetWorkOrRegister::Register(reg) => reg, 582 }; 583 584 let mut inner = self.inner.lock(); 585 loop { 586 if let Some(work) = inner.pop_work() { 587 return Ok(Some(work)); 588 } 589 590 inner.looper_flags |= LOOPER_WAITING | LOOPER_WAITING_PROC; 591 let signal_pending = self.work_condvar.wait_interruptible_freezable(&mut inner); 592 inner.looper_flags &= !(LOOPER_WAITING | LOOPER_WAITING_PROC); 593 594 if signal_pending || inner.looper_need_return { 595 // We need to return now. We need to pull the thread off the list of ready threads 596 // (by dropping `reg`), then check the state again after it's off the list to 597 // ensure that something was not queued in the meantime. If something has been 598 // queued, we just return it (instead of the error). 599 drop(inner); 600 drop(reg); 601 602 let res = match self.inner.lock().pop_work() { 603 Some(work) => Ok(Some(work)), 604 None if signal_pending => Err(EINTR), 605 None => Ok(None), 606 }; 607 return res; 608 } 609 } 610 } 611 612 /// Push the provided work item to be delivered to user space via this thread. 613 /// 614 /// Returns whether the item was successfully pushed. This can only fail if the thread is dead. 615 pub(crate) fn push_work(&self, work: DLArc<dyn DeliverToRead>) -> PushWorkRes { 616 let sync = work.should_sync_wakeup(); 617 618 let res = self.inner.lock().push_work(work); 619 620 if res.is_ok() { 621 if sync { 622 self.work_condvar.notify_sync(); 623 } else { 624 self.work_condvar.notify_one(); 625 } 626 } 627 628 res 629 } 630 631 /// Attempts to push to given work item to the thread if it's a looper thread (i.e., if it's 632 /// part of a thread pool) and is alive. Otherwise, push the work item to the process instead. 633 pub(crate) fn push_work_if_looper(&self, work: DLArc<dyn DeliverToRead>) -> BinderResult { 634 let mut inner = self.inner.lock(); 635 if inner.is_looper() && !inner.is_dead { 636 inner.push_work(work); 637 Ok(()) 638 } else { 639 drop(inner); 640 self.process.push_work(work) 641 } 642 } 643 644 pub(crate) fn push_work_deferred(&self, work: DLArc<dyn DeliverToRead>) { 645 self.inner.lock().push_work_deferred(work); 646 } 647 648 pub(crate) fn push_return_work(&self, reply: u32) { 649 self.inner.lock().push_return_work(reply); 650 } 651 652 fn translate_object( 653 &self, 654 obj_index: usize, 655 offset: usize, 656 object: BinderObjectRef<'_>, 657 view: &mut AllocationView<'_>, 658 allow_fds: bool, 659 sg_state: &mut ScatterGatherState, 660 ) -> BinderResult { 661 match object { 662 BinderObjectRef::Binder(obj) => { 663 let strong = obj.hdr.type_ == BINDER_TYPE_BINDER; 664 // SAFETY: `binder` is a `binder_uintptr_t`; any bit pattern is a valid 665 // representation. 666 let ptr = unsafe { obj.__bindgen_anon_1.binder } as _; 667 let cookie = obj.cookie as _; 668 let flags = obj.flags as _; 669 let node = self 670 .process 671 .as_arc_borrow() 672 .get_node(ptr, cookie, flags, strong, self)?; 673 security::binder_transfer_binder(&self.process.cred, &view.alloc.process.cred)?; 674 view.transfer_binder_object(offset, obj, strong, node)?; 675 } 676 BinderObjectRef::Handle(obj) => { 677 let strong = obj.hdr.type_ == BINDER_TYPE_HANDLE; 678 // SAFETY: `handle` is a `u32`; any bit pattern is a valid representation. 679 let handle = unsafe { obj.__bindgen_anon_1.handle } as _; 680 let node = self.process.get_node_from_handle(handle, strong)?; 681 security::binder_transfer_binder(&self.process.cred, &view.alloc.process.cred)?; 682 view.transfer_binder_object(offset, obj, strong, node)?; 683 } 684 BinderObjectRef::Fd(obj) => { 685 if !allow_fds { 686 return Err(EPERM.into()); 687 } 688 689 // SAFETY: `fd` is a `u32`; any bit pattern is a valid representation. 690 let fd = unsafe { obj.__bindgen_anon_1.fd }; 691 let file = LocalFile::fget(fd)?; 692 // SAFETY: The binder driver never calls `fdget_pos` and this code runs from an 693 // ioctl, so there are no active calls to `fdget_pos` on this thread. 694 let file = unsafe { LocalFile::assume_no_fdget_pos(file) }; 695 security::binder_transfer_file( 696 &self.process.cred, 697 &view.alloc.process.cred, 698 &file, 699 )?; 700 701 let mut obj_write = BinderFdObject::default(); 702 obj_write.hdr.type_ = BINDER_TYPE_FD; 703 // This will be overwritten with the actual fd when the transaction is received. 704 obj_write.__bindgen_anon_1.fd = u32::MAX; 705 obj_write.cookie = obj.cookie; 706 view.write::<BinderFdObject>(offset, &obj_write)?; 707 708 const FD_FIELD_OFFSET: usize = 709 core::mem::offset_of!(uapi::binder_fd_object, __bindgen_anon_1.fd); 710 711 let field_offset = offset + FD_FIELD_OFFSET; 712 713 view.alloc.info_add_fd(file, field_offset, false)?; 714 } 715 BinderObjectRef::Ptr(obj) => { 716 let obj_length = obj.length.try_into().map_err(|_| EINVAL)?; 717 let alloc_offset = match sg_state.unused_buffer_space.claim_next(obj_length) { 718 Ok(alloc_offset) => alloc_offset, 719 Err(err) => { 720 pr_warn!( 721 "Failed to claim space for a BINDER_TYPE_PTR. (offset: {}, limit: {}, size: {})", 722 sg_state.unused_buffer_space.offset, 723 sg_state.unused_buffer_space.limit, 724 obj_length, 725 ); 726 return Err(err.into()); 727 } 728 }; 729 730 let sg_state_idx = sg_state.sg_entries.len(); 731 sg_state.sg_entries.push( 732 ScatterGatherEntry { 733 obj_index, 734 offset: alloc_offset, 735 sender_uaddr: obj.buffer as _, 736 length: obj_length, 737 pointer_fixups: KVec::new(), 738 fixup_min_offset: 0, 739 }, 740 GFP_KERNEL, 741 )?; 742 743 let buffer_ptr_in_user_space = (view.alloc.ptr + alloc_offset) as u64; 744 745 if obj.flags & uapi::BINDER_BUFFER_FLAG_HAS_PARENT == 0 { 746 sg_state.ancestors.clear(); 747 sg_state.ancestors.push(sg_state_idx, GFP_KERNEL)?; 748 } else { 749 // Another buffer also has a pointer to this buffer, and we need to fixup that 750 // pointer too. 751 752 let parent_index = usize::try_from(obj.parent).map_err(|_| EINVAL)?; 753 let parent_offset = usize::try_from(obj.parent_offset).map_err(|_| EINVAL)?; 754 755 let info = sg_state.validate_parent_fixup( 756 parent_index, 757 parent_offset, 758 size_of::<u64>(), 759 )?; 760 761 sg_state.ancestors.truncate(info.num_ancestors); 762 sg_state.ancestors.push(sg_state_idx, GFP_KERNEL)?; 763 764 let parent_entry = match sg_state.sg_entries.get_mut(info.parent_sg_index) { 765 Some(parent_entry) => parent_entry, 766 None => { 767 pr_err!( 768 "validate_parent_fixup returned index out of bounds for sg.entries" 769 ); 770 return Err(EINVAL.into()); 771 } 772 }; 773 774 parent_entry.fixup_min_offset = info.new_min_offset; 775 parent_entry.pointer_fixups.push( 776 PointerFixupEntry::Fixup { 777 pointer_value: buffer_ptr_in_user_space, 778 target_offset: info.target_offset, 779 }, 780 GFP_KERNEL, 781 )?; 782 } 783 784 let mut obj_write = BinderBufferObject::default(); 785 obj_write.hdr.type_ = BINDER_TYPE_PTR; 786 obj_write.flags = obj.flags; 787 obj_write.buffer = buffer_ptr_in_user_space; 788 obj_write.length = obj.length; 789 obj_write.parent = obj.parent; 790 obj_write.parent_offset = obj.parent_offset; 791 view.write::<BinderBufferObject>(offset, &obj_write)?; 792 } 793 BinderObjectRef::Fda(obj) => { 794 if !allow_fds { 795 return Err(EPERM.into()); 796 } 797 let parent_index = usize::try_from(obj.parent).map_err(|_| EINVAL)?; 798 let parent_offset = usize::try_from(obj.parent_offset).map_err(|_| EINVAL)?; 799 let num_fds = usize::try_from(obj.num_fds).map_err(|_| EINVAL)?; 800 let fds_len = num_fds.checked_mul(size_of::<u32>()).ok_or(EINVAL)?; 801 802 if !is_aligned(parent_offset, size_of::<u32>()) { 803 return Err(EINVAL.into()); 804 } 805 806 let info = sg_state.validate_parent_fixup(parent_index, parent_offset, fds_len)?; 807 view.alloc.info_add_fd_reserve(num_fds)?; 808 809 sg_state.ancestors.truncate(info.num_ancestors); 810 let parent_entry = match sg_state.sg_entries.get_mut(info.parent_sg_index) { 811 Some(parent_entry) => parent_entry, 812 None => { 813 pr_err!( 814 "validate_parent_fixup returned index out of bounds for sg.entries" 815 ); 816 return Err(EINVAL.into()); 817 } 818 }; 819 820 if !is_aligned(parent_entry.sender_uaddr, size_of::<u32>()) { 821 return Err(EINVAL.into()); 822 } 823 824 parent_entry.fixup_min_offset = info.new_min_offset; 825 parent_entry 826 .pointer_fixups 827 .push( 828 PointerFixupEntry::Skip { 829 skip: fds_len, 830 target_offset: info.target_offset, 831 }, 832 GFP_KERNEL, 833 ) 834 .map_err(|_| ENOMEM)?; 835 836 let fda_uaddr = parent_entry 837 .sender_uaddr 838 .checked_add(parent_offset) 839 .ok_or(EINVAL)?; 840 841 let mut fda_bytes = KVec::new(); 842 UserSlice::new(UserPtr::from_addr(fda_uaddr as _), fds_len) 843 .read_all(&mut fda_bytes, GFP_KERNEL)?; 844 845 if fds_len != fda_bytes.len() { 846 pr_err!("UserSlice::read_all returned wrong length in BINDER_TYPE_FDA"); 847 return Err(EINVAL.into()); 848 } 849 850 for i in (0..fds_len).step_by(size_of::<u32>()) { 851 let fd = { 852 let mut fd_bytes = [0u8; size_of::<u32>()]; 853 fd_bytes.copy_from_slice(&fda_bytes[i..i + size_of::<u32>()]); 854 u32::from_ne_bytes(fd_bytes) 855 }; 856 857 let file = LocalFile::fget(fd)?; 858 // SAFETY: The binder driver never calls `fdget_pos` and this code runs from an 859 // ioctl, so there are no active calls to `fdget_pos` on this thread. 860 let file = unsafe { LocalFile::assume_no_fdget_pos(file) }; 861 security::binder_transfer_file( 862 &self.process.cred, 863 &view.alloc.process.cred, 864 &file, 865 )?; 866 867 // The `validate_parent_fixup` call ensuers that this addition will not 868 // overflow. 869 view.alloc.info_add_fd(file, info.target_offset + i, true)?; 870 } 871 drop(fda_bytes); 872 873 let mut obj_write = BinderFdArrayObject::default(); 874 obj_write.hdr.type_ = BINDER_TYPE_FDA; 875 obj_write.num_fds = obj.num_fds; 876 obj_write.parent = obj.parent; 877 obj_write.parent_offset = obj.parent_offset; 878 view.write::<BinderFdArrayObject>(offset, &obj_write)?; 879 } 880 } 881 Ok(()) 882 } 883 884 fn apply_sg(&self, alloc: &mut Allocation, sg_state: &mut ScatterGatherState) -> BinderResult { 885 for sg_entry in &mut sg_state.sg_entries { 886 let mut end_of_previous_fixup = sg_entry.offset; 887 let offset_end = sg_entry.offset.checked_add(sg_entry.length).ok_or(EINVAL)?; 888 889 let mut reader = 890 UserSlice::new(UserPtr::from_addr(sg_entry.sender_uaddr), sg_entry.length).reader(); 891 for fixup in &mut sg_entry.pointer_fixups { 892 let (fixup_len, fixup_offset) = match fixup { 893 PointerFixupEntry::Fixup { target_offset, .. } => { 894 (size_of::<u64>(), *target_offset) 895 } 896 PointerFixupEntry::Skip { 897 skip, 898 target_offset, 899 } => (*skip, *target_offset), 900 }; 901 902 let target_offset_end = fixup_offset.checked_add(fixup_len).ok_or(EINVAL)?; 903 if fixup_offset < end_of_previous_fixup || offset_end < target_offset_end { 904 pr_warn!( 905 "Fixups oob {} {} {} {}", 906 fixup_offset, 907 end_of_previous_fixup, 908 offset_end, 909 target_offset_end 910 ); 911 return Err(EINVAL.into()); 912 } 913 914 let copy_off = end_of_previous_fixup; 915 let copy_len = fixup_offset - end_of_previous_fixup; 916 if let Err(err) = alloc.copy_into(&mut reader, copy_off, copy_len) { 917 pr_warn!("Failed copying into alloc: {:?}", err); 918 return Err(err.into()); 919 } 920 if let PointerFixupEntry::Fixup { pointer_value, .. } = fixup { 921 let res = alloc.write::<u64>(fixup_offset, pointer_value); 922 if let Err(err) = res { 923 pr_warn!("Failed copying ptr into alloc: {:?}", err); 924 return Err(err.into()); 925 } 926 } 927 if let Err(err) = reader.skip(fixup_len) { 928 pr_warn!("Failed skipping {} from reader: {:?}", fixup_len, err); 929 return Err(err.into()); 930 } 931 end_of_previous_fixup = target_offset_end; 932 } 933 let copy_off = end_of_previous_fixup; 934 let copy_len = offset_end - end_of_previous_fixup; 935 if let Err(err) = alloc.copy_into(&mut reader, copy_off, copy_len) { 936 pr_warn!("Failed copying remainder into alloc: {:?}", err); 937 return Err(err.into()); 938 } 939 } 940 Ok(()) 941 } 942 943 /// This method copies the payload of a transaction into the target process. 944 /// 945 /// The resulting payload will have several different components, which will be stored next to 946 /// each other in the allocation. Furthermore, various objects can be embedded in the payload, 947 /// and those objects have to be translated so that they make sense to the target transaction. 948 pub(crate) fn copy_transaction_data( 949 &self, 950 to_process: Arc<Process>, 951 tr: &BinderTransactionDataSg, 952 debug_id: usize, 953 allow_fds: bool, 954 txn_security_ctx_offset: Option<&mut usize>, 955 ) -> BinderResult<NewAllocation> { 956 let trd = &tr.transaction_data; 957 let is_oneway = trd.flags & TF_ONE_WAY != 0; 958 let mut secctx = if let Some(offset) = txn_security_ctx_offset { 959 let secid = self.process.cred.get_secid(); 960 let ctx = match security::SecurityCtx::from_secid(secid) { 961 Ok(ctx) => ctx, 962 Err(err) => { 963 pr_warn!("Failed to get security ctx for id {}: {:?}", secid, err); 964 return Err(err.into()); 965 } 966 }; 967 Some((offset, ctx)) 968 } else { 969 None 970 }; 971 972 let data_size = trd.data_size.try_into().map_err(|_| EINVAL)?; 973 let aligned_data_size = ptr_align(data_size).ok_or(EINVAL)?; 974 let offsets_size: usize = trd.offsets_size.try_into().map_err(|_| EINVAL)?; 975 let buffers_size: usize = tr.buffers_size.try_into().map_err(|_| EINVAL)?; 976 let aligned_secctx_size = match secctx.as_ref() { 977 Some((_offset, ctx)) => ptr_align(ctx.len()).ok_or(EINVAL)?, 978 None => 0, 979 }; 980 981 if !is_aligned(offsets_size, size_of::<u64>()) { 982 return Err(EINVAL.into()); 983 } 984 if !is_aligned(buffers_size, size_of::<u64>()) { 985 return Err(EINVAL.into()); 986 } 987 988 // This guarantees that at least `sizeof(usize)` bytes will be allocated. 989 let len = usize::max( 990 aligned_data_size 991 .checked_add(offsets_size) 992 .and_then(|sum| sum.checked_add(buffers_size)) 993 .and_then(|sum| sum.checked_add(aligned_secctx_size)) 994 .ok_or(ENOMEM)?, 995 size_of::<u64>(), 996 ); 997 let secctx_off = aligned_data_size + offsets_size + buffers_size; 998 let mut alloc = 999 match to_process.buffer_alloc(debug_id, len, is_oneway, self.process.task.pid()) { 1000 Ok(alloc) => alloc, 1001 Err(err) => { 1002 pr_warn!( 1003 "Failed to allocate buffer. len:{}, is_oneway:{}", 1004 len, 1005 is_oneway 1006 ); 1007 return Err(err); 1008 } 1009 }; 1010 1011 // SAFETY: This accesses a union field, but it's okay because the field's type is valid for 1012 // all bit-patterns. 1013 let trd_data_ptr = unsafe { &trd.data.ptr }; 1014 let mut buffer_reader = 1015 UserSlice::new(UserPtr::from_addr(trd_data_ptr.buffer as _), data_size).reader(); 1016 let mut end_of_previous_object = 0; 1017 let mut sg_state = None; 1018 1019 // Copy offsets if there are any. 1020 if offsets_size > 0 { 1021 let mut offsets_reader = 1022 UserSlice::new(UserPtr::from_addr(trd_data_ptr.offsets as _), offsets_size) 1023 .reader(); 1024 1025 let offsets_start = aligned_data_size; 1026 let offsets_end = aligned_data_size + offsets_size; 1027 1028 // This state is used for BINDER_TYPE_PTR objects. 1029 let sg_state = sg_state.insert(ScatterGatherState { 1030 unused_buffer_space: UnusedBufferSpace { 1031 offset: offsets_end, 1032 limit: offsets_end + buffers_size, 1033 }, 1034 sg_entries: KVec::new(), 1035 ancestors: KVec::new(), 1036 }); 1037 1038 // Traverse the objects specified. 1039 let mut view = AllocationView::new(&mut alloc, data_size); 1040 for (index, index_offset) in (offsets_start..offsets_end) 1041 .step_by(size_of::<u64>()) 1042 .enumerate() 1043 { 1044 let offset = offsets_reader.read::<u64>()?; 1045 view.alloc.write(index_offset, &offset)?; 1046 let offset: usize = offset.try_into().map_err(|_| EINVAL)?; 1047 1048 if offset < end_of_previous_object || !is_aligned(offset, size_of::<u32>()) { 1049 pr_warn!("Got transaction with invalid offset."); 1050 return Err(EINVAL.into()); 1051 } 1052 1053 // Copy data between two objects. 1054 if end_of_previous_object < offset { 1055 view.copy_into( 1056 &mut buffer_reader, 1057 end_of_previous_object, 1058 offset - end_of_previous_object, 1059 )?; 1060 } 1061 1062 let mut object = BinderObject::read_from(&mut buffer_reader)?; 1063 1064 match self.translate_object( 1065 index, 1066 offset, 1067 object.as_ref(), 1068 &mut view, 1069 allow_fds, 1070 sg_state, 1071 ) { 1072 Ok(()) => end_of_previous_object = offset + object.size(), 1073 Err(err) => { 1074 pr_warn!("Error while translating object."); 1075 return Err(err); 1076 } 1077 } 1078 1079 // Update the indexes containing objects to clean up. 1080 let offset_after_object = index_offset + size_of::<u64>(); 1081 view.alloc 1082 .set_info_offsets(offsets_start..offset_after_object); 1083 } 1084 } 1085 1086 // Copy remaining raw data. 1087 alloc.copy_into( 1088 &mut buffer_reader, 1089 end_of_previous_object, 1090 data_size - end_of_previous_object, 1091 )?; 1092 1093 if let Some(sg_state) = sg_state.as_mut() { 1094 if let Err(err) = self.apply_sg(&mut alloc, sg_state) { 1095 pr_warn!("Failure in apply_sg: {:?}", err); 1096 return Err(err); 1097 } 1098 } 1099 1100 if let Some((off_out, secctx)) = secctx.as_mut() { 1101 if let Err(err) = alloc.write(secctx_off, secctx.as_bytes()) { 1102 pr_warn!("Failed to write security context: {:?}", err); 1103 return Err(err.into()); 1104 } 1105 **off_out = secctx_off; 1106 } 1107 Ok(alloc) 1108 } 1109 1110 fn unwind_transaction_stack(self: &Arc<Self>) { 1111 let mut thread = self.clone(); 1112 while let Ok(transaction) = { 1113 let mut inner = thread.inner.lock(); 1114 inner.pop_transaction_to_reply(thread.as_ref()) 1115 } { 1116 let reply = Err(BR_DEAD_REPLY); 1117 if !transaction.from.deliver_single_reply(reply, &transaction) { 1118 break; 1119 } 1120 1121 thread = transaction.from.clone(); 1122 } 1123 } 1124 1125 pub(crate) fn deliver_reply( 1126 &self, 1127 reply: Result<DLArc<Transaction>, u32>, 1128 transaction: &DArc<Transaction>, 1129 ) { 1130 if self.deliver_single_reply(reply, transaction) { 1131 transaction.from.unwind_transaction_stack(); 1132 } 1133 } 1134 1135 /// Delivers a reply to the thread that started a transaction. The reply can either be a 1136 /// reply-transaction or an error code to be delivered instead. 1137 /// 1138 /// Returns whether the thread is dead. If it is, the caller is expected to unwind the 1139 /// transaction stack by completing transactions for threads that are dead. 1140 fn deliver_single_reply( 1141 &self, 1142 reply: Result<DLArc<Transaction>, u32>, 1143 transaction: &DArc<Transaction>, 1144 ) -> bool { 1145 if let Ok(transaction) = &reply { 1146 transaction.set_outstanding(&mut self.process.inner.lock()); 1147 } 1148 1149 { 1150 let mut inner = self.inner.lock(); 1151 if !inner.pop_transaction_replied(transaction) { 1152 return false; 1153 } 1154 1155 if inner.is_dead { 1156 return true; 1157 } 1158 1159 match reply { 1160 Ok(work) => { 1161 inner.push_work(work); 1162 } 1163 Err(code) => inner.push_reply_work(code), 1164 } 1165 } 1166 1167 // Notify the thread now that we've released the inner lock. 1168 self.work_condvar.notify_sync(); 1169 false 1170 } 1171 1172 /// Determines if the given transaction is the current transaction for this thread. 1173 fn is_current_transaction(&self, transaction: &DArc<Transaction>) -> bool { 1174 let inner = self.inner.lock(); 1175 match &inner.current_transaction { 1176 None => false, 1177 Some(current) => Arc::ptr_eq(current, transaction), 1178 } 1179 } 1180 1181 /// Determines the current top of the transaction stack. It fails if the top is in another 1182 /// thread (i.e., this thread belongs to a stack but it has called another thread). The top is 1183 /// [`None`] if the thread is not currently participating in a transaction stack. 1184 fn top_of_transaction_stack(&self) -> Result<Option<DArc<Transaction>>> { 1185 let inner = self.inner.lock(); 1186 if let Some(cur) = &inner.current_transaction { 1187 if core::ptr::eq(self, cur.from.as_ref()) { 1188 pr_warn!("got new transaction with bad transaction stack"); 1189 return Err(EINVAL); 1190 } 1191 Ok(Some(cur.clone())) 1192 } else { 1193 Ok(None) 1194 } 1195 } 1196 1197 fn transaction<T>(self: &Arc<Self>, tr: &BinderTransactionDataSg, inner: T) 1198 where 1199 T: FnOnce(&Arc<Self>, &BinderTransactionDataSg) -> BinderResult, 1200 { 1201 if let Err(err) = inner(self, tr) { 1202 if err.should_pr_warn() { 1203 let mut ee = self.inner.lock().extended_error; 1204 ee.command = err.reply; 1205 ee.param = err.as_errno(); 1206 pr_warn!( 1207 "Transaction failed: {:?} my_pid:{}", 1208 err, 1209 self.process.pid_in_current_ns() 1210 ); 1211 } 1212 1213 self.push_return_work(err.reply); 1214 } 1215 } 1216 1217 fn transaction_inner(self: &Arc<Self>, tr: &BinderTransactionDataSg) -> BinderResult { 1218 // SAFETY: Handle's type has no invalid bit patterns. 1219 let handle = unsafe { tr.transaction_data.target.handle }; 1220 let node_ref = self.process.get_transaction_node(handle)?; 1221 security::binder_transaction(&self.process.cred, &node_ref.node.owner.cred)?; 1222 // TODO: We need to ensure that there isn't a pending transaction in the work queue. How 1223 // could this happen? 1224 let top = self.top_of_transaction_stack()?; 1225 let list_completion = DTRWrap::arc_try_new(DeliverCode::new(BR_TRANSACTION_COMPLETE))?; 1226 let completion = list_completion.clone_arc(); 1227 let transaction = Transaction::new(node_ref, top, self, tr)?; 1228 1229 // Check that the transaction stack hasn't changed while the lock was released, then update 1230 // it with the new transaction. 1231 { 1232 let mut inner = self.inner.lock(); 1233 if !transaction.is_stacked_on(&inner.current_transaction) { 1234 pr_warn!("Transaction stack changed during transaction!"); 1235 return Err(EINVAL.into()); 1236 } 1237 inner.current_transaction = Some(transaction.clone_arc()); 1238 // We push the completion as a deferred work so that we wait for the reply before 1239 // returning to userland. 1240 inner.push_work_deferred(list_completion); 1241 } 1242 1243 if let Err(e) = transaction.submit() { 1244 completion.skip(); 1245 // Define `transaction` first to drop it after `inner`. 1246 let transaction; 1247 let mut inner = self.inner.lock(); 1248 transaction = inner.current_transaction.take().unwrap(); 1249 inner.current_transaction = transaction.clone_next(); 1250 Err(e) 1251 } else { 1252 Ok(()) 1253 } 1254 } 1255 1256 fn reply_inner(self: &Arc<Self>, tr: &BinderTransactionDataSg) -> BinderResult { 1257 let orig = self.inner.lock().pop_transaction_to_reply(self)?; 1258 if !orig.from.is_current_transaction(&orig) { 1259 return Err(EINVAL.into()); 1260 } 1261 1262 // We need to complete the transaction even if we cannot complete building the reply. 1263 let out = (|| -> BinderResult<_> { 1264 let completion = DTRWrap::arc_try_new(DeliverCode::new(BR_TRANSACTION_COMPLETE))?; 1265 let process = orig.from.process.clone(); 1266 let allow_fds = orig.flags & TF_ACCEPT_FDS != 0; 1267 let reply = Transaction::new_reply(self, process, tr, allow_fds)?; 1268 self.inner.lock().push_work(completion); 1269 orig.from.deliver_reply(Ok(reply), &orig); 1270 Ok(()) 1271 })() 1272 .map_err(|mut err| { 1273 // At this point we only return `BR_TRANSACTION_COMPLETE` to the caller, and we must let 1274 // the sender know that the transaction has completed (with an error in this case). 1275 pr_warn!( 1276 "Failure {:?} during reply - delivering BR_FAILED_REPLY to sender.", 1277 err 1278 ); 1279 let reply = Err(BR_FAILED_REPLY); 1280 orig.from.deliver_reply(reply, &orig); 1281 err.reply = BR_TRANSACTION_COMPLETE; 1282 err 1283 }); 1284 1285 out 1286 } 1287 1288 fn oneway_transaction_inner(self: &Arc<Self>, tr: &BinderTransactionDataSg) -> BinderResult { 1289 // SAFETY: The `handle` field is valid for all possible byte values, so reading from the 1290 // union is okay. 1291 let handle = unsafe { tr.transaction_data.target.handle }; 1292 let node_ref = self.process.get_transaction_node(handle)?; 1293 security::binder_transaction(&self.process.cred, &node_ref.node.owner.cred)?; 1294 let transaction = Transaction::new(node_ref, None, self, tr)?; 1295 let code = if self.process.is_oneway_spam_detection_enabled() 1296 && transaction.oneway_spam_detected 1297 { 1298 BR_ONEWAY_SPAM_SUSPECT 1299 } else { 1300 BR_TRANSACTION_COMPLETE 1301 }; 1302 let list_completion = DTRWrap::arc_try_new(DeliverCode::new(code))?; 1303 let completion = list_completion.clone_arc(); 1304 self.inner.lock().push_work(list_completion); 1305 match transaction.submit() { 1306 Ok(()) => Ok(()), 1307 Err(err) => { 1308 completion.skip(); 1309 Err(err) 1310 } 1311 } 1312 } 1313 1314 fn write(self: &Arc<Self>, req: &mut BinderWriteRead) -> Result { 1315 let write_start = req.write_buffer.wrapping_add(req.write_consumed); 1316 let write_len = req.write_size.saturating_sub(req.write_consumed); 1317 let mut reader = 1318 UserSlice::new(UserPtr::from_addr(write_start as _), write_len as _).reader(); 1319 1320 while reader.len() >= size_of::<u32>() && self.inner.lock().return_work.is_unused() { 1321 let before = reader.len(); 1322 let cmd = reader.read::<u32>()?; 1323 GLOBAL_STATS.inc_bc(cmd); 1324 self.process.stats.inc_bc(cmd); 1325 match cmd { 1326 BC_TRANSACTION => { 1327 let tr = reader.read::<BinderTransactionData>()?.with_buffers_size(0); 1328 if tr.transaction_data.flags & TF_ONE_WAY != 0 { 1329 self.transaction(&tr, Self::oneway_transaction_inner); 1330 } else { 1331 self.transaction(&tr, Self::transaction_inner); 1332 } 1333 } 1334 BC_TRANSACTION_SG => { 1335 let tr = reader.read::<BinderTransactionDataSg>()?; 1336 if tr.transaction_data.flags & TF_ONE_WAY != 0 { 1337 self.transaction(&tr, Self::oneway_transaction_inner); 1338 } else { 1339 self.transaction(&tr, Self::transaction_inner); 1340 } 1341 } 1342 BC_REPLY => { 1343 let tr = reader.read::<BinderTransactionData>()?.with_buffers_size(0); 1344 self.transaction(&tr, Self::reply_inner) 1345 } 1346 BC_REPLY_SG => { 1347 let tr = reader.read::<BinderTransactionDataSg>()?; 1348 self.transaction(&tr, Self::reply_inner) 1349 } 1350 BC_FREE_BUFFER => { 1351 let buffer = self.process.buffer_get(reader.read()?); 1352 if let Some(buffer) = buffer { 1353 if buffer.looper_need_return_on_free() { 1354 self.inner.lock().looper_need_return = true; 1355 } 1356 drop(buffer); 1357 } 1358 } 1359 BC_INCREFS => { 1360 self.process 1361 .as_arc_borrow() 1362 .update_ref(reader.read()?, true, false)? 1363 } 1364 BC_ACQUIRE => { 1365 self.process 1366 .as_arc_borrow() 1367 .update_ref(reader.read()?, true, true)? 1368 } 1369 BC_RELEASE => { 1370 self.process 1371 .as_arc_borrow() 1372 .update_ref(reader.read()?, false, true)? 1373 } 1374 BC_DECREFS => { 1375 self.process 1376 .as_arc_borrow() 1377 .update_ref(reader.read()?, false, false)? 1378 } 1379 BC_INCREFS_DONE => self.process.inc_ref_done(&mut reader, false)?, 1380 BC_ACQUIRE_DONE => self.process.inc_ref_done(&mut reader, true)?, 1381 BC_REQUEST_DEATH_NOTIFICATION => self.process.request_death(&mut reader, self)?, 1382 BC_CLEAR_DEATH_NOTIFICATION => self.process.clear_death(&mut reader, self)?, 1383 BC_DEAD_BINDER_DONE => self.process.dead_binder_done(reader.read()?, self), 1384 BC_REGISTER_LOOPER => { 1385 let valid = self.process.register_thread(); 1386 self.inner.lock().looper_register(valid); 1387 } 1388 BC_ENTER_LOOPER => self.inner.lock().looper_enter(), 1389 BC_EXIT_LOOPER => self.inner.lock().looper_exit(), 1390 BC_REQUEST_FREEZE_NOTIFICATION => self.process.request_freeze_notif(&mut reader)?, 1391 BC_CLEAR_FREEZE_NOTIFICATION => self.process.clear_freeze_notif(&mut reader)?, 1392 BC_FREEZE_NOTIFICATION_DONE => self.process.freeze_notif_done(&mut reader)?, 1393 1394 // Fail if given an unknown error code. 1395 // BC_ATTEMPT_ACQUIRE and BC_ACQUIRE_RESULT are no longer supported. 1396 _ => return Err(EINVAL), 1397 } 1398 // Update the number of write bytes consumed. 1399 req.write_consumed += (before - reader.len()) as u64; 1400 } 1401 1402 Ok(()) 1403 } 1404 1405 fn read(self: &Arc<Self>, req: &mut BinderWriteRead, wait: bool) -> Result { 1406 let read_start = req.read_buffer.wrapping_add(req.read_consumed); 1407 let read_len = req.read_size.saturating_sub(req.read_consumed); 1408 let mut writer = BinderReturnWriter::new( 1409 UserSlice::new(UserPtr::from_addr(read_start as _), read_len as _).writer(), 1410 self, 1411 ); 1412 let (in_pool, use_proc_queue) = { 1413 let inner = self.inner.lock(); 1414 (inner.is_looper(), inner.should_use_process_work_queue()) 1415 }; 1416 1417 let getter = if use_proc_queue { 1418 Self::get_work 1419 } else { 1420 Self::get_work_local 1421 }; 1422 1423 // Reserve some room at the beginning of the read buffer so that we can send a 1424 // BR_SPAWN_LOOPER if we need to. 1425 let mut has_noop_placeholder = false; 1426 if req.read_consumed == 0 { 1427 if let Err(err) = writer.write_code(BR_NOOP) { 1428 pr_warn!("Failure when writing BR_NOOP at beginning of buffer."); 1429 return Err(err); 1430 } 1431 has_noop_placeholder = true; 1432 } 1433 1434 // Loop doing work while there is room in the buffer. 1435 let initial_len = writer.len(); 1436 while writer.len() >= size_of::<uapi::binder_transaction_data_secctx>() + 4 { 1437 match getter(self, wait && initial_len == writer.len()) { 1438 Ok(Some(work)) => match work.into_arc().do_work(self, &mut writer) { 1439 Ok(true) => {} 1440 Ok(false) => break, 1441 Err(err) => { 1442 return Err(err); 1443 } 1444 }, 1445 Ok(None) => { 1446 break; 1447 } 1448 Err(err) => { 1449 // Propagate the error if we haven't written anything else. 1450 if err != EINTR && err != EAGAIN { 1451 pr_warn!("Failure in work getter: {:?}", err); 1452 } 1453 if initial_len == writer.len() { 1454 return Err(err); 1455 } else { 1456 break; 1457 } 1458 } 1459 } 1460 } 1461 1462 req.read_consumed += read_len - writer.len() as u64; 1463 1464 // Write BR_SPAWN_LOOPER if the process needs more threads for its pool. 1465 if has_noop_placeholder && in_pool && self.process.needs_thread() { 1466 let mut writer = 1467 UserSlice::new(UserPtr::from_addr(req.read_buffer as _), req.read_size as _) 1468 .writer(); 1469 writer.write(&BR_SPAWN_LOOPER)?; 1470 } 1471 Ok(()) 1472 } 1473 1474 pub(crate) fn write_read(self: &Arc<Self>, data: UserSlice, wait: bool) -> Result { 1475 let (mut reader, mut writer) = data.reader_writer(); 1476 let mut req = reader.read::<BinderWriteRead>()?; 1477 1478 // Go through the write buffer. 1479 let mut ret = Ok(()); 1480 if req.write_size > 0 { 1481 ret = self.write(&mut req); 1482 if let Err(err) = ret { 1483 pr_warn!( 1484 "Write failure {:?} in pid:{}", 1485 err, 1486 self.process.pid_in_current_ns() 1487 ); 1488 req.read_consumed = 0; 1489 writer.write(&req)?; 1490 self.inner.lock().looper_need_return = false; 1491 return ret; 1492 } 1493 } 1494 1495 // Go through the work queue. 1496 if req.read_size > 0 { 1497 ret = self.read(&mut req, wait); 1498 if ret.is_err() && ret != Err(EINTR) { 1499 pr_warn!( 1500 "Read failure {:?} in pid:{}", 1501 ret, 1502 self.process.pid_in_current_ns() 1503 ); 1504 } 1505 } 1506 1507 // Write the request back so that the consumed fields are visible to the caller. 1508 writer.write(&req)?; 1509 1510 self.inner.lock().looper_need_return = false; 1511 1512 ret 1513 } 1514 1515 pub(crate) fn poll(&self, file: &File, table: PollTable<'_>) -> (bool, u32) { 1516 table.register_wait(file, &self.work_condvar); 1517 let mut inner = self.inner.lock(); 1518 (inner.should_use_process_work_queue(), inner.poll()) 1519 } 1520 1521 /// Make the call to `get_work` or `get_work_local` return immediately, if any. 1522 pub(crate) fn exit_looper(&self) { 1523 let mut inner = self.inner.lock(); 1524 let should_notify = inner.looper_flags & LOOPER_WAITING != 0; 1525 if should_notify { 1526 inner.looper_need_return = true; 1527 } 1528 drop(inner); 1529 1530 if should_notify { 1531 self.work_condvar.notify_one(); 1532 } 1533 } 1534 1535 pub(crate) fn notify_if_poll_ready(&self, sync: bool) { 1536 // Determine if we need to notify. This requires the lock. 1537 let inner = self.inner.lock(); 1538 let notify = inner.looper_flags & LOOPER_POLL != 0 && inner.should_use_process_work_queue(); 1539 drop(inner); 1540 1541 // Now that the lock is no longer held, notify the waiters if we have to. 1542 if notify { 1543 if sync { 1544 self.work_condvar.notify_sync(); 1545 } else { 1546 self.work_condvar.notify_one(); 1547 } 1548 } 1549 } 1550 1551 pub(crate) fn release(self: &Arc<Self>) { 1552 self.inner.lock().is_dead = true; 1553 1554 //self.work_condvar.clear(); 1555 self.unwind_transaction_stack(); 1556 1557 // Cancel all pending work items. 1558 while let Ok(Some(work)) = self.get_work_local(false) { 1559 work.into_arc().cancel(); 1560 } 1561 } 1562} 1563 1564#[pin_data] 1565struct ThreadError { 1566 error_code: AtomicU32, 1567 #[pin] 1568 links_track: AtomicTracker, 1569} 1570 1571impl ThreadError { 1572 fn try_new() -> Result<DArc<Self>> { 1573 DTRWrap::arc_pin_init(pin_init!(Self { 1574 error_code: AtomicU32::new(BR_OK), 1575 links_track <- AtomicTracker::new(), 1576 })) 1577 .map(ListArc::into_arc) 1578 } 1579 1580 fn set_error_code(&self, code: u32) { 1581 self.error_code.store(code, Ordering::Relaxed); 1582 } 1583 1584 fn is_unused(&self) -> bool { 1585 self.error_code.load(Ordering::Relaxed) == BR_OK 1586 } 1587} 1588 1589impl DeliverToRead for ThreadError { 1590 fn do_work( 1591 self: DArc<Self>, 1592 _thread: &Thread, 1593 writer: &mut BinderReturnWriter<'_>, 1594 ) -> Result<bool> { 1595 let code = self.error_code.load(Ordering::Relaxed); 1596 self.error_code.store(BR_OK, Ordering::Relaxed); 1597 writer.write_code(code)?; 1598 Ok(true) 1599 } 1600 1601 fn cancel(self: DArc<Self>) {} 1602 1603 fn should_sync_wakeup(&self) -> bool { 1604 false 1605 } 1606 1607 fn debug_print(&self, m: &SeqFile, prefix: &str, _tprefix: &str) -> Result<()> { 1608 seq_print!( 1609 m, 1610 "{}transaction error: {}\n", 1611 prefix, 1612 self.error_code.load(Ordering::Relaxed) 1613 ); 1614 Ok(()) 1615 } 1616} 1617 1618kernel::list::impl_list_arc_safe! { 1619 impl ListArcSafe<0> for ThreadError { 1620 tracked_by links_track: AtomicTracker; 1621 } 1622}
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