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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/child/child_process.h"
#include <string.h>
#include "base/clang_profiling_buildflags.h"
#include "base/functional/bind.h"
#include "base/message_loop/message_pump_type.h"
#include "base/process/process_handle.h"
#include "base/synchronization/waitable_event.h"
#include "base/task/thread_pool/thread_pool_instance.h"
#include "base/threading/hang_watcher.h"
#include "base/threading/thread.h"
#include "build/build_config.h"
#include "build/config/compiler/compiler_buildflags.h"
#include "content/child/child_thread_impl.h"
#include "content/common/process_visibility_tracker.h"
#include "mojo/public/cpp/bindings/interface_endpoint_client.h"
#include "sandbox/policy/sandbox_type.h"
#include "services/tracing/public/cpp/trace_startup.h"
#include "third_party/blink/public/common/features.h"
#if BUILDFLAG(CLANG_PROFILING_INSIDE_SANDBOX)
#include "base/test/clang_profiling.h"
#endif
#if BUILDFLAG(IS_ANDROID)
#include "content/common/android/cpu_time_metrics.h"
#endif
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
#include "content/child/sandboxed_process_thread_type_handler.h"
#endif
namespace content {
namespace {
constinit thread_local ChildProcess* child_process = nullptr;
class ChildIOThread : public base::Thread {
public:
ChildIOThread() : base::Thread("Chrome_ChildIOThread") {}
ChildIOThread(const ChildIOThread&) = delete;
ChildIOThread(ChildIOThread&&) = delete;
ChildIOThread& operator=(const ChildIOThread&) = delete;
ChildIOThread& operator=(ChildIOThread&&) = delete;
void Run(base::RunLoop* run_loop) override {
mojo::InterfaceEndpointClient::SetThreadNameSuffixForMetrics(
"ChildIOThread");
base::ScopedClosureRunner unregister_thread_closure;
if (base::HangWatcher::IsIOThreadHangWatchingEnabled()) {
unregister_thread_closure = base::HangWatcher::RegisterThread(
base::HangWatcher::ThreadType::kIOThread);
}
base::Thread::Run(run_loop);
}
};
} // namespace
ChildProcess::ChildProcess(base::ThreadType io_thread_type,
std::unique_ptr<base::ThreadPoolInstance::InitParams>
thread_pool_init_params)
: resetter_(&child_process, this, nullptr),
io_thread_(std::make_unique<ChildIOThread>()) {
// Start ThreadPoolInstance if not already done. A ThreadPoolInstance
// should already exist, and may already be running when ChildProcess is
// instantiated in the browser process or in a test process.
//
// There are 3 possibilities:
//
// 1. ChildProcess is actually being constructed on a thread in the browser
// process (eg. for single-process mode). The ThreadPool was already
// started on the main thread, but this happened before the ChildProcess
// thread was created, which creates a happens-before relationship. So
// it's safe to check WasStartedUnsafe().
// 2. ChildProcess is being constructed in a test. The ThreadPool was
// already started by TaskEnvironment on the main thread. Depending on
// the test, ChildProcess might be constructed on the main thread or
// another thread that was created after the test start. Either way, it's
// safe to check WasStartedUnsafe().
// 3. ChildProcess is being constructed in a subprocess from ContentMain, on
// the main thread. This is the same thread that created the ThreadPool
// so it's safe to check WasStartedUnsafe().
//
// Note that the only case we expect WasStartedUnsafe() to return true
// should be running on the main thread. So if there's a logic error and a
// stale read causes WasStartedUnsafe() to return false after the
// ThreadPool was started, Start() will correctly DCHECK as it's called on the
// wrong thread. (The result never flips from true to false so a stale read
// should never return true.)
auto* thread_pool = base::ThreadPoolInstance::Get();
DCHECK(thread_pool);
if (!thread_pool->WasStartedUnsafe()) {
if (thread_pool_init_params)
thread_pool->Start(*thread_pool_init_params.get());
else
thread_pool->StartWithDefaultParams();
initialized_thread_pool_ = true;
}
tracing::InitTracingPostFeatureList(/*enable_consumer=*/false);
// Ensure the visibility tracker is created on the main thread.
ProcessVisibilityTracker::GetInstance();
#if BUILDFLAG(IS_ANDROID)
SetupCpuTimeMetrics();
#endif
// We can't recover from failing to start the IO thread.
base::Thread::Options thread_options(base::MessagePumpType::IO, 0);
thread_options.thread_type = io_thread_type;
// TODO(crbug.com/40226692): Figure out whether IS_ANDROID can be lifted here.
#if BUILDFLAG(IS_ANDROID)
// TODO(reveman): Remove this in favor of setting it explicitly for each type
// of process.
thread_options.thread_type = base::ThreadType::kDisplayCritical;
#endif
CHECK(io_thread_->StartWithOptions(std::move(thread_options)));
io_thread_runner_ = io_thread_->task_runner();
}
ChildProcess::ChildProcess(
scoped_refptr<base::SingleThreadTaskRunner> io_thread_runner)
: resetter_(&child_process, this, nullptr),
io_thread_runner_(std::move(io_thread_runner)) {}
ChildProcess::~ChildProcess() {
DCHECK_EQ(child_process, this);
// Signal this event before destroying the child process. That way all
// background threads can cleanup.
// For example, in the renderer the RenderThread instances will be able to
// notice shutdown before the render process begins waiting for them to exit.
shutdown_event_.Signal();
if (main_thread_) { // null in unittests.
main_thread_->Shutdown();
if (main_thread_->ShouldBeDestroyed()) {
main_thread_.reset();
} else {
// Leak the main_thread_. See a comment in
// RenderThreadImpl::ShouldBeDestroyed.
main_thread_.release();
}
}
if (io_thread_) {
io_thread_->Stop();
io_thread_.reset();
}
if (initialized_thread_pool_) {
DCHECK(base::ThreadPoolInstance::Get());
base::ThreadPoolInstance::Get()->Shutdown();
}
#if BUILDFLAG(CLANG_PROFILING_INSIDE_SANDBOX) && BUILDFLAG(CLANG_PGO_PROFILING)
// Flush the profiling data to disk. Doing this manually (vs relying on this
// being done automatically when the process exits) will ensure that this data
// doesn't get lost if the process is fast killed.
base::WriteClangProfilingProfile();
#endif
}
ChildThreadImpl* ChildProcess::main_thread() {
return main_thread_.get();
}
void ChildProcess::set_main_thread(ChildThreadImpl* thread) {
main_thread_.reset(thread);
}
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
void ChildProcess::SetIOThreadType(base::ThreadType thread_type) {
if (!io_thread_) {
return;
}
// The SandboxedProcessThreadTypeHandler isn't created in
// in --single-process mode or if certain base::Features are disabled. See
// instances of SandboxedProcessThreadTypeHandler::Create() for more details.
if (SandboxedProcessThreadTypeHandler* sandboxed_process_thread_type_handler =
SandboxedProcessThreadTypeHandler::Get()) {
sandboxed_process_thread_type_handler->HandleThreadTypeChange(
io_thread_->GetThreadId(), base::ThreadType::kDisplayCritical);
}
}
#endif
void ChildProcess::AddRefProcess() {
DCHECK(!main_thread_.get() || // null in unittests.
main_thread_->main_thread_runner()->BelongsToCurrentThread());
ref_count_++;
}
void ChildProcess::ReleaseProcess() {
DCHECK(!main_thread_.get() || // null in unittests.
main_thread_->main_thread_runner()->BelongsToCurrentThread());
DCHECK(ref_count_);
if (--ref_count_)
return;
if (main_thread_) // null in unittests.
main_thread_->OnProcessFinalRelease();
}
ChildProcess* ChildProcess::current() {
return child_process;
}
base::WaitableEvent* ChildProcess::GetShutDownEvent() {
return &shutdown_event_;
}
} // namespace content
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