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Diffstat (limited to 'mojo/edk/system/core.cc')
| -rw-r--r-- | mojo/edk/system/core.cc | 609 |
1 files changed, 0 insertions, 609 deletions
diff --git a/mojo/edk/system/core.cc b/mojo/edk/system/core.cc deleted file mode 100644 index 6189e50..0000000 --- a/mojo/edk/system/core.cc +++ /dev/null @@ -1,609 +0,0 @@ -// Copyright 2013 The Chromium Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. - -#include "mojo/edk/system/core.h" - -#include <vector> - -#include "base/logging.h" -#include "base/time/time.h" -#include "mojo/edk/embedder/platform_shared_buffer.h" -#include "mojo/edk/embedder/platform_support.h" -#include "mojo/edk/system/async_waiter.h" -#include "mojo/edk/system/configuration.h" -#include "mojo/edk/system/data_pipe.h" -#include "mojo/edk/system/data_pipe_consumer_dispatcher.h" -#include "mojo/edk/system/data_pipe_producer_dispatcher.h" -#include "mojo/edk/system/dispatcher.h" -#include "mojo/edk/system/handle_signals_state.h" -#include "mojo/edk/system/local_data_pipe.h" -#include "mojo/edk/system/memory.h" -#include "mojo/edk/system/message_pipe.h" -#include "mojo/edk/system/message_pipe_dispatcher.h" -#include "mojo/edk/system/shared_buffer_dispatcher.h" -#include "mojo/edk/system/waiter.h" -#include "mojo/public/c/system/macros.h" - -namespace mojo { -namespace system { - -// Implementation notes -// -// Mojo primitives are implemented by the singleton |Core| object. Most calls -// are for a "primary" handle (the first argument). |Core::GetDispatcher()| is -// used to look up a |Dispatcher| object for a given handle. That object -// implements most primitives for that object. The wait primitives are not -// attached to objects and are implemented by |Core| itself. -// -// Some objects have multiple handles associated to them, e.g., message pipes -// (which have two). In such a case, there is still a |Dispatcher| (e.g., -// |MessagePipeDispatcher|) for each handle, with each handle having a strong -// reference to the common "secondary" object (e.g., |MessagePipe|). This -// secondary object does NOT have any references to the |Dispatcher|s (even if -// it did, it wouldn't be able to do anything with them due to lock order -// requirements -- see below). -// -// Waiting is implemented by having the thread that wants to wait call the -// |Dispatcher|s for the handles that it wants to wait on with a |Waiter| -// object; this |Waiter| object may be created on the stack of that thread or be -// kept in thread local storage for that thread (TODO(vtl): future improvement). -// The |Dispatcher| then adds the |Waiter| to an |AwakableList| that's either -// owned by that |Dispatcher| (see |SimpleDispatcher|) or by a secondary object -// (e.g., |MessagePipe|). To signal/wake a |Waiter|, the object in question -- -// either a |SimpleDispatcher| or a secondary object -- talks to its -// |AwakableList|. - -// Thread-safety notes -// -// Mojo primitives calls are thread-safe. We achieve this with relatively -// fine-grained locking. There is a global handle table lock. This lock should -// be held as briefly as possible (TODO(vtl): a future improvement would be to -// switch it to a reader-writer lock). Each |Dispatcher| object then has a lock -// (which subclasses can use to protect their data). -// -// The lock ordering is as follows: -// 1. global handle table lock, global mapping table lock -// 2. |Dispatcher| locks -// 3. secondary object locks -// ... -// INF. |Waiter| locks -// -// Notes: -// - While holding a |Dispatcher| lock, you may not unconditionally attempt -// to take another |Dispatcher| lock. (This has consequences on the -// concurrency semantics of |MojoWriteMessage()| when passing handles.) -// Doing so would lead to deadlock. -// - Locks at the "INF" level may not have any locks taken while they are -// held. - -// TODO(vtl): This should take a |scoped_ptr<PlatformSupport>| as a parameter. -Core::Core(scoped_ptr<embedder::PlatformSupport> platform_support) - : platform_support_(platform_support.Pass()) { -} - -Core::~Core() { -} - -MojoHandle Core::AddDispatcher(const scoped_refptr<Dispatcher>& dispatcher) { - base::AutoLock locker(handle_table_lock_); - return handle_table_.AddDispatcher(dispatcher); -} - -scoped_refptr<Dispatcher> Core::GetDispatcher(MojoHandle handle) { - if (handle == MOJO_HANDLE_INVALID) - return nullptr; - - base::AutoLock locker(handle_table_lock_); - return handle_table_.GetDispatcher(handle); -} - -MojoResult Core::AsyncWait(MojoHandle handle, - MojoHandleSignals signals, - base::Callback<void(MojoResult)> callback) { - scoped_refptr<Dispatcher> dispatcher = GetDispatcher(handle); - DCHECK(dispatcher); - - scoped_ptr<AsyncWaiter> waiter = make_scoped_ptr(new AsyncWaiter(callback)); - MojoResult rv = dispatcher->AddAwakable(waiter.get(), signals, 0, nullptr); - if (rv == MOJO_RESULT_OK) - ignore_result(waiter.release()); - return rv; -} - -MojoTimeTicks Core::GetTimeTicksNow() { - return base::TimeTicks::Now().ToInternalValue(); -} - -MojoResult Core::Close(MojoHandle handle) { - if (handle == MOJO_HANDLE_INVALID) - return MOJO_RESULT_INVALID_ARGUMENT; - - scoped_refptr<Dispatcher> dispatcher; - { - base::AutoLock locker(handle_table_lock_); - MojoResult result = - handle_table_.GetAndRemoveDispatcher(handle, &dispatcher); - if (result != MOJO_RESULT_OK) - return result; - } - - // The dispatcher doesn't have a say in being closed, but gets notified of it. - // Note: This is done outside of |handle_table_lock_|. As a result, there's a - // race condition that the dispatcher must handle; see the comment in - // |Dispatcher| in dispatcher.h. - return dispatcher->Close(); -} - -MojoResult Core::Wait(MojoHandle handle, - MojoHandleSignals signals, - MojoDeadline deadline, - UserPointer<MojoHandleSignalsState> signals_state) { - uint32_t unused = static_cast<uint32_t>(-1); - HandleSignalsState hss; - MojoResult rv = WaitManyInternal(&handle, &signals, 1, deadline, &unused, - signals_state.IsNull() ? nullptr : &hss); - if (rv != MOJO_RESULT_INVALID_ARGUMENT && !signals_state.IsNull()) - signals_state.Put(hss); - return rv; -} - -MojoResult Core::WaitMany(UserPointer<const MojoHandle> handles, - UserPointer<const MojoHandleSignals> signals, - uint32_t num_handles, - MojoDeadline deadline, - UserPointer<uint32_t> result_index, - UserPointer<MojoHandleSignalsState> signals_states) { - if (num_handles < 1) - return MOJO_RESULT_INVALID_ARGUMENT; - if (num_handles > GetConfiguration().max_wait_many_num_handles) - return MOJO_RESULT_RESOURCE_EXHAUSTED; - - UserPointer<const MojoHandle>::Reader handles_reader(handles, num_handles); - UserPointer<const MojoHandleSignals>::Reader signals_reader(signals, - num_handles); - uint32_t index = static_cast<uint32_t>(-1); - MojoResult rv; - if (signals_states.IsNull()) { - rv = WaitManyInternal(handles_reader.GetPointer(), - signals_reader.GetPointer(), num_handles, deadline, - &index, nullptr); - } else { - UserPointer<MojoHandleSignalsState>::Writer signals_states_writer( - signals_states, num_handles); - // Note: The |reinterpret_cast| is safe, since |HandleSignalsState| is a - // subclass of |MojoHandleSignalsState| that doesn't add any data members. - rv = WaitManyInternal(handles_reader.GetPointer(), - signals_reader.GetPointer(), num_handles, deadline, - &index, reinterpret_cast<HandleSignalsState*>( - signals_states_writer.GetPointer())); - if (rv != MOJO_RESULT_INVALID_ARGUMENT) - signals_states_writer.Commit(); - } - if (index != static_cast<uint32_t>(-1) && !result_index.IsNull()) - result_index.Put(index); - return rv; -} - -MojoResult Core::CreateMessagePipe( - UserPointer<const MojoCreateMessagePipeOptions> options, - UserPointer<MojoHandle> message_pipe_handle0, - UserPointer<MojoHandle> message_pipe_handle1) { - MojoCreateMessagePipeOptions validated_options = {}; - MojoResult result = - MessagePipeDispatcher::ValidateCreateOptions(options, &validated_options); - if (result != MOJO_RESULT_OK) - return result; - - scoped_refptr<MessagePipeDispatcher> dispatcher0( - new MessagePipeDispatcher(validated_options)); - scoped_refptr<MessagePipeDispatcher> dispatcher1( - new MessagePipeDispatcher(validated_options)); - - std::pair<MojoHandle, MojoHandle> handle_pair; - { - base::AutoLock locker(handle_table_lock_); - handle_pair = handle_table_.AddDispatcherPair(dispatcher0, dispatcher1); - } - if (handle_pair.first == MOJO_HANDLE_INVALID) { - DCHECK_EQ(handle_pair.second, MOJO_HANDLE_INVALID); - LOG(ERROR) << "Handle table full"; - dispatcher0->Close(); - dispatcher1->Close(); - return MOJO_RESULT_RESOURCE_EXHAUSTED; - } - - scoped_refptr<MessagePipe> message_pipe(MessagePipe::CreateLocalLocal()); - dispatcher0->Init(message_pipe, 0); - dispatcher1->Init(message_pipe, 1); - - message_pipe_handle0.Put(handle_pair.first); - message_pipe_handle1.Put(handle_pair.second); - return MOJO_RESULT_OK; -} - -// Implementation note: To properly cancel waiters and avoid other races, this -// does not transfer dispatchers from one handle to another, even when sending a -// message in-process. Instead, it must transfer the "contents" of the -// dispatcher to a new dispatcher, and then close the old dispatcher. If this -// isn't done, in the in-process case, calls on the old handle may complete -// after the the message has been received and a new handle created (and -// possibly even after calls have been made on the new handle). -MojoResult Core::WriteMessage(MojoHandle message_pipe_handle, - UserPointer<const void> bytes, - uint32_t num_bytes, - UserPointer<const MojoHandle> handles, - uint32_t num_handles, - MojoWriteMessageFlags flags) { - scoped_refptr<Dispatcher> dispatcher(GetDispatcher(message_pipe_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - // Easy case: not sending any handles. - if (num_handles == 0) - return dispatcher->WriteMessage(bytes, num_bytes, nullptr, flags); - - // We have to handle |handles| here, since we have to mark them busy in the - // global handle table. We can't delegate this to the dispatcher, since the - // handle table lock must be acquired before the dispatcher lock. - // - // (This leads to an oddity: |handles|/|num_handles| are always verified for - // validity, even for dispatchers that don't support |WriteMessage()| and will - // simply return failure unconditionally. It also breaks the usual - // left-to-right verification order of arguments.) - if (num_handles > GetConfiguration().max_message_num_handles) - return MOJO_RESULT_RESOURCE_EXHAUSTED; - - UserPointer<const MojoHandle>::Reader handles_reader(handles, num_handles); - - // We'll need to hold on to the dispatchers so that we can pass them on to - // |WriteMessage()| and also so that we can unlock their locks afterwards - // without accessing the handle table. These can be dumb pointers, since their - // entries in the handle table won't get removed (since they'll be marked as - // busy). - std::vector<DispatcherTransport> transports(num_handles); - - // When we pass handles, we have to try to take all their dispatchers' locks - // and mark the handles as busy. If the call succeeds, we then remove the - // handles from the handle table. - { - base::AutoLock locker(handle_table_lock_); - MojoResult result = handle_table_.MarkBusyAndStartTransport( - message_pipe_handle, handles_reader.GetPointer(), num_handles, - &transports); - if (result != MOJO_RESULT_OK) - return result; - } - - MojoResult rv = - dispatcher->WriteMessage(bytes, num_bytes, &transports, flags); - - // We need to release the dispatcher locks before we take the handle table - // lock. - for (uint32_t i = 0; i < num_handles; i++) - transports[i].End(); - - { - base::AutoLock locker(handle_table_lock_); - if (rv == MOJO_RESULT_OK) { - handle_table_.RemoveBusyHandles(handles_reader.GetPointer(), num_handles); - } else { - handle_table_.RestoreBusyHandles(handles_reader.GetPointer(), - num_handles); - } - } - - return rv; -} - -MojoResult Core::ReadMessage(MojoHandle message_pipe_handle, - UserPointer<void> bytes, - UserPointer<uint32_t> num_bytes, - UserPointer<MojoHandle> handles, - UserPointer<uint32_t> num_handles, - MojoReadMessageFlags flags) { - scoped_refptr<Dispatcher> dispatcher(GetDispatcher(message_pipe_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - uint32_t num_handles_value = num_handles.IsNull() ? 0 : num_handles.Get(); - - MojoResult rv; - if (num_handles_value == 0) { - // Easy case: won't receive any handles. - rv = dispatcher->ReadMessage(bytes, num_bytes, nullptr, &num_handles_value, - flags); - } else { - DispatcherVector dispatchers; - rv = dispatcher->ReadMessage(bytes, num_bytes, &dispatchers, - &num_handles_value, flags); - if (!dispatchers.empty()) { - DCHECK_EQ(rv, MOJO_RESULT_OK); - DCHECK(!num_handles.IsNull()); - DCHECK_LE(dispatchers.size(), static_cast<size_t>(num_handles_value)); - - bool success; - UserPointer<MojoHandle>::Writer handles_writer(handles, - dispatchers.size()); - { - base::AutoLock locker(handle_table_lock_); - success = handle_table_.AddDispatcherVector( - dispatchers, handles_writer.GetPointer()); - } - if (success) { - handles_writer.Commit(); - } else { - LOG(ERROR) << "Received message with " << dispatchers.size() - << " handles, but handle table full"; - // Close dispatchers (outside the lock). - for (size_t i = 0; i < dispatchers.size(); i++) { - if (dispatchers[i]) - dispatchers[i]->Close(); - } - if (rv == MOJO_RESULT_OK) - rv = MOJO_RESULT_RESOURCE_EXHAUSTED; - } - } - } - - if (!num_handles.IsNull()) - num_handles.Put(num_handles_value); - return rv; -} - -MojoResult Core::CreateDataPipe( - UserPointer<const MojoCreateDataPipeOptions> options, - UserPointer<MojoHandle> data_pipe_producer_handle, - UserPointer<MojoHandle> data_pipe_consumer_handle) { - MojoCreateDataPipeOptions validated_options = {}; - MojoResult result = - DataPipe::ValidateCreateOptions(options, &validated_options); - if (result != MOJO_RESULT_OK) - return result; - - scoped_refptr<DataPipeProducerDispatcher> producer_dispatcher( - new DataPipeProducerDispatcher()); - scoped_refptr<DataPipeConsumerDispatcher> consumer_dispatcher( - new DataPipeConsumerDispatcher()); - - std::pair<MojoHandle, MojoHandle> handle_pair; - { - base::AutoLock locker(handle_table_lock_); - handle_pair = handle_table_.AddDispatcherPair(producer_dispatcher, - consumer_dispatcher); - } - if (handle_pair.first == MOJO_HANDLE_INVALID) { - DCHECK_EQ(handle_pair.second, MOJO_HANDLE_INVALID); - LOG(ERROR) << "Handle table full"; - producer_dispatcher->Close(); - consumer_dispatcher->Close(); - return MOJO_RESULT_RESOURCE_EXHAUSTED; - } - DCHECK_NE(handle_pair.second, MOJO_HANDLE_INVALID); - - scoped_refptr<DataPipe> data_pipe(new LocalDataPipe(validated_options)); - producer_dispatcher->Init(data_pipe); - consumer_dispatcher->Init(data_pipe); - - data_pipe_producer_handle.Put(handle_pair.first); - data_pipe_consumer_handle.Put(handle_pair.second); - return MOJO_RESULT_OK; -} - -MojoResult Core::WriteData(MojoHandle data_pipe_producer_handle, - UserPointer<const void> elements, - UserPointer<uint32_t> num_bytes, - MojoWriteDataFlags flags) { - scoped_refptr<Dispatcher> dispatcher( - GetDispatcher(data_pipe_producer_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - return dispatcher->WriteData(elements, num_bytes, flags); -} - -MojoResult Core::BeginWriteData(MojoHandle data_pipe_producer_handle, - UserPointer<void*> buffer, - UserPointer<uint32_t> buffer_num_bytes, - MojoWriteDataFlags flags) { - scoped_refptr<Dispatcher> dispatcher( - GetDispatcher(data_pipe_producer_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - return dispatcher->BeginWriteData(buffer, buffer_num_bytes, flags); -} - -MojoResult Core::EndWriteData(MojoHandle data_pipe_producer_handle, - uint32_t num_bytes_written) { - scoped_refptr<Dispatcher> dispatcher( - GetDispatcher(data_pipe_producer_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - return dispatcher->EndWriteData(num_bytes_written); -} - -MojoResult Core::ReadData(MojoHandle data_pipe_consumer_handle, - UserPointer<void> elements, - UserPointer<uint32_t> num_bytes, - MojoReadDataFlags flags) { - scoped_refptr<Dispatcher> dispatcher( - GetDispatcher(data_pipe_consumer_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - return dispatcher->ReadData(elements, num_bytes, flags); -} - -MojoResult Core::BeginReadData(MojoHandle data_pipe_consumer_handle, - UserPointer<const void*> buffer, - UserPointer<uint32_t> buffer_num_bytes, - MojoReadDataFlags flags) { - scoped_refptr<Dispatcher> dispatcher( - GetDispatcher(data_pipe_consumer_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - return dispatcher->BeginReadData(buffer, buffer_num_bytes, flags); -} - -MojoResult Core::EndReadData(MojoHandle data_pipe_consumer_handle, - uint32_t num_bytes_read) { - scoped_refptr<Dispatcher> dispatcher( - GetDispatcher(data_pipe_consumer_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - return dispatcher->EndReadData(num_bytes_read); -} - -MojoResult Core::CreateSharedBuffer( - UserPointer<const MojoCreateSharedBufferOptions> options, - uint64_t num_bytes, - UserPointer<MojoHandle> shared_buffer_handle) { - MojoCreateSharedBufferOptions validated_options = {}; - MojoResult result = SharedBufferDispatcher::ValidateCreateOptions( - options, &validated_options); - if (result != MOJO_RESULT_OK) - return result; - - scoped_refptr<SharedBufferDispatcher> dispatcher; - result = SharedBufferDispatcher::Create(platform_support(), validated_options, - num_bytes, &dispatcher); - if (result != MOJO_RESULT_OK) { - DCHECK(!dispatcher); - return result; - } - - MojoHandle h = AddDispatcher(dispatcher); - if (h == MOJO_HANDLE_INVALID) { - LOG(ERROR) << "Handle table full"; - dispatcher->Close(); - return MOJO_RESULT_RESOURCE_EXHAUSTED; - } - - shared_buffer_handle.Put(h); - return MOJO_RESULT_OK; -} - -MojoResult Core::DuplicateBufferHandle( - MojoHandle buffer_handle, - UserPointer<const MojoDuplicateBufferHandleOptions> options, - UserPointer<MojoHandle> new_buffer_handle) { - scoped_refptr<Dispatcher> dispatcher(GetDispatcher(buffer_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - // Don't verify |options| here; that's the dispatcher's job. - scoped_refptr<Dispatcher> new_dispatcher; - MojoResult result = - dispatcher->DuplicateBufferHandle(options, &new_dispatcher); - if (result != MOJO_RESULT_OK) - return result; - - MojoHandle new_handle = AddDispatcher(new_dispatcher); - if (new_handle == MOJO_HANDLE_INVALID) { - LOG(ERROR) << "Handle table full"; - dispatcher->Close(); - return MOJO_RESULT_RESOURCE_EXHAUSTED; - } - - new_buffer_handle.Put(new_handle); - return MOJO_RESULT_OK; -} - -MojoResult Core::MapBuffer(MojoHandle buffer_handle, - uint64_t offset, - uint64_t num_bytes, - UserPointer<void*> buffer, - MojoMapBufferFlags flags) { - scoped_refptr<Dispatcher> dispatcher(GetDispatcher(buffer_handle)); - if (!dispatcher) - return MOJO_RESULT_INVALID_ARGUMENT; - - scoped_ptr<embedder::PlatformSharedBufferMapping> mapping; - MojoResult result = dispatcher->MapBuffer(offset, num_bytes, flags, &mapping); - if (result != MOJO_RESULT_OK) - return result; - - DCHECK(mapping); - void* address = mapping->GetBase(); - { - base::AutoLock locker(mapping_table_lock_); - result = mapping_table_.AddMapping(mapping.Pass()); - } - if (result != MOJO_RESULT_OK) - return result; - - buffer.Put(address); - return MOJO_RESULT_OK; -} - -MojoResult Core::UnmapBuffer(UserPointer<void> buffer) { - base::AutoLock locker(mapping_table_lock_); - return mapping_table_.RemoveMapping(buffer.GetPointerValue()); -} - -// Note: We allow |handles| to repeat the same handle multiple times, since -// different flags may be specified. -// TODO(vtl): This incurs a performance cost in |Remove()|. Analyze this -// more carefully and address it if necessary. -MojoResult Core::WaitManyInternal(const MojoHandle* handles, - const MojoHandleSignals* signals, - uint32_t num_handles, - MojoDeadline deadline, - uint32_t* result_index, - HandleSignalsState* signals_states) { - DCHECK_GT(num_handles, 0u); - DCHECK_EQ(*result_index, static_cast<uint32_t>(-1)); - - DispatcherVector dispatchers; - dispatchers.reserve(num_handles); - for (uint32_t i = 0; i < num_handles; i++) { - scoped_refptr<Dispatcher> dispatcher = GetDispatcher(handles[i]); - if (!dispatcher) { - *result_index = i; - return MOJO_RESULT_INVALID_ARGUMENT; - } - dispatchers.push_back(dispatcher); - } - - // TODO(vtl): Should make the waiter live (permanently) in TLS. - Waiter waiter; - waiter.Init(); - - uint32_t i; - MojoResult rv = MOJO_RESULT_OK; - for (i = 0; i < num_handles; i++) { - rv = dispatchers[i]->AddAwakable( - &waiter, signals[i], i, signals_states ? &signals_states[i] : nullptr); - if (rv != MOJO_RESULT_OK) { - *result_index = i; - break; - } - } - uint32_t num_added = i; - - if (rv == MOJO_RESULT_ALREADY_EXISTS) - rv = MOJO_RESULT_OK; // The i-th one is already "triggered". - else if (rv == MOJO_RESULT_OK) - rv = waiter.Wait(deadline, result_index); - - // Make sure no other dispatchers try to wake |waiter| for the current - // |Wait()|/|WaitMany()| call. (Only after doing this can |waiter| be - // destroyed, but this would still be required if the waiter were in TLS.) - for (i = 0; i < num_added; i++) { - dispatchers[i]->RemoveAwakable( - &waiter, signals_states ? &signals_states[i] : nullptr); - } - if (signals_states) { - for (; i < num_handles; i++) - signals_states[i] = dispatchers[i]->GetHandleSignalsState(); - } - - return rv; -} - -} // namespace system -} // namespace mojo |