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content / browser / child_process_launcher_helper.cc [blame]
// Copyright 2017 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/browser/child_process_launcher_helper.h"
#include <optional>
#include "base/base_switches.h"
#include "base/command_line.h"
#include "base/functional/bind.h"
#include "base/memory/shared_memory_switch.h"
#include "base/metrics/histogram_macros.h"
#include "base/metrics/histogram_shared_memory.h"
#include "base/no_destructor.h"
#include "base/process/launch.h"
#include "base/strings/string_number_conversions.h"
#include "base/task/lazy_thread_pool_task_runner.h"
#include "base/task/sequenced_task_runner.h"
#include "base/task/single_thread_task_runner.h"
#include "base/task/single_thread_task_runner_thread_mode.h"
#include "base/task/task_traits.h"
#include "build/build_config.h"
#include "components/tracing/common/tracing_switches.h"
#include "components/variations/active_field_trials.h"
#include "content/browser/child_process_launcher.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/child_process_launcher_utils.h"
#include "content/public/common/content_descriptors.h"
#include "content/public/common/content_features.h"
#include "content/public/common/content_switches.h"
#include "content/public/common/sandboxed_process_launcher_delegate.h"
#include "mojo/core/configuration.h"
#include "mojo/public/cpp/platform/platform_channel.h"
#include "services/tracing/public/cpp/trace_startup.h"
#if BUILDFLAG(IS_ANDROID)
#include "content/browser/android/launcher_thread.h"
#endif
#if BUILDFLAG(IS_IOS)
#include "base/apple/mach_port_rendezvous.h"
#endif
namespace content {
namespace internal {
namespace {
void RecordHistogramsOnLauncherThread(base::TimeDelta launch_time) {
DCHECK(CurrentlyOnProcessLauncherTaskRunner());
// Log the launch time, separating out the first one (which will likely be
// slower due to the rest of the browser initializing at the same time).
static bool done_first_launch = false;
if (done_first_launch) {
UMA_HISTOGRAM_TIMES("MPArch.ChildProcessLaunchSubsequent", launch_time);
} else {
UMA_HISTOGRAM_TIMES("MPArch.ChildProcessLaunchFirst", launch_time);
done_first_launch = true;
}
}
// If the histogram shared memory region is valid and passing the histogram
// shared memory region via the command line is enabled, update the launch
// parameters to pass the shared memory handle. The allocation of the shared
// memory region is dependent on the process-type being launched, and non-fatal
// if not enabled.
//
// This function is NOP if the platform does not use Blink.
void PassHistogramSharedMemoryHandle(
[[maybe_unused]] base::UnsafeSharedMemoryRegion histogram_memory_region,
[[maybe_unused]] base::CommandLine* command_line,
[[maybe_unused]] base::LaunchOptions* launch_options,
[[maybe_unused]] FileMappedForLaunch* files_to_register) {
// TODO(crbug.com/40109064): Once all process types support histogram shared
// memory being passed at launch, remove this if.
if (!histogram_memory_region.IsValid()) {
return;
}
CHECK(command_line);
CHECK(histogram_memory_region.IsValid());
#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
// TODO(crbug.com/40109064): content::FileMappedForLaunch (POSIX) is redundant
// wrt the base::LaunchOptions::<platform-specific-handles-to-transfer>
// members. Refactor this so that the details of base::Launch vs Zygote on
// (some) POSIX platforms is an implementation detail and not exposed here.
// I.e., populate launch options (like for all other platforms) then if it's
// a Zygote launch pull out the handles to transfer and send them to the
// zygote, instead of (for posix only) ignoring the launch-options here,
// populating the |files_to_register| param then (if there's no zygote)
// filling in |launch_options|
CHECK(files_to_register);
base::ScopedFD descriptor_to_transfer;
#else
CHECK(launch_options);
#endif
#if BUILDFLAG(USE_BLINK)
DCHECK(histogram_memory_region.IsValid());
base::HistogramSharedMemory::AddToLaunchParameters(
std::move(histogram_memory_region),
#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
/*descriptor_key=*/kHistogramSharedMemoryDescriptor,
/*descriptor_to_share=*/descriptor_to_transfer,
#endif // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
command_line, launch_options);
#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
if (descriptor_to_transfer.is_valid()) {
files_to_register->Transfer(kHistogramSharedMemoryDescriptor,
std::move(descriptor_to_transfer));
}
#endif // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
#endif // BUILDFLAG(USE_BLINK)
}
// Update the process launch parameters to transmit the field trial shared
// memory handle to the child process via the command line.
//
// This function is NOP if the platform does not use Blink.
void PassFieldTrialSharedMemoryHandle(
[[maybe_unused]] base::CommandLine* command_line,
[[maybe_unused]] base::LaunchOptions* launch_options,
[[maybe_unused]] FileMappedForLaunch* files_to_register) {
CHECK(command_line);
#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
// TODO(crbug.com/40109064): content::FileMappedForLaunch (POSIX) is redundant
// wrt the base::LaunchOptions::<platform-specific-handles-to-transfer>
// members. Refactor this so that the details of base::Launch vs Zygote on
// (some) POSIX platforms is an implementation detail and not exposed here.
// I.e., populate launch options (like for all other platforms) then if it's
// a Zygote launch pull out the handles to transfer and send them to the
// zygote, instead of (for posix only) ignoring the launch-options here,
// populating the |files_to_register| param then (if there's no zygote)
// filling in |launch_options|
CHECK(files_to_register);
base::ScopedFD descriptor_to_transfer;
#else
CHECK(launch_options);
#endif
#if BUILDFLAG(USE_BLINK)
variations::PopulateLaunchOptionsWithVariationsInfo(
#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
/*descriptor_key=*/kFieldTrialDescriptor,
/*descriptor_to_share=*/descriptor_to_transfer,
#endif // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
command_line, launch_options);
#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
if (descriptor_to_transfer.is_valid()) {
files_to_register->Transfer(kFieldTrialDescriptor,
std::move(descriptor_to_transfer));
}
#endif // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
#endif // BUILDFLAG(USE_BLINK)
}
void PassStartupTracingConfigSharedMemoryHandle(
[[maybe_unused]] base::ReadOnlySharedMemoryRegion read_only_memory_region,
[[maybe_unused]] base::CommandLine* command_line,
[[maybe_unused]] base::LaunchOptions* launch_options,
[[maybe_unused]] FileMappedForLaunch* files_to_register) {
CHECK(command_line);
if (!read_only_memory_region.IsValid()) {
return;
}
CHECK(read_only_memory_region.IsValid());
#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
CHECK(files_to_register);
base::ScopedFD descriptor_to_transfer;
#else
CHECK(launch_options);
#endif
#if BUILDFLAG(USE_BLINK)
tracing::AddTraceConfigToLaunchParameters(std::move(read_only_memory_region),
#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
kTraceConfigSharedMemoryDescriptor,
descriptor_to_transfer,
#endif
command_line, launch_options);
#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
if (descriptor_to_transfer.is_valid()) {
files_to_register->Transfer(kTraceConfigSharedMemoryDescriptor,
std::move(descriptor_to_transfer));
}
#endif // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
#endif // BUILDFLAG(USE_BLINK)
}
} // namespace
ChildProcessLauncherHelper::Process::Process() = default;
ChildProcessLauncherHelper::Process::~Process() = default;
ChildProcessLauncherHelper::Process::Process(Process&& other)
: process(std::move(other.process))
#if BUILDFLAG(USE_ZYGOTE)
,
zygote(other.zygote)
#endif
#if BUILDFLAG(IS_FUCHSIA)
,
sandbox_policy(std::move(other.sandbox_policy))
#endif
{
}
ChildProcessLauncherHelper::Process&
ChildProcessLauncherHelper::Process::Process::operator=(
ChildProcessLauncherHelper::Process&& other) = default;
ChildProcessLauncherHelper::ChildProcessLauncherHelper(
int child_process_id,
std::unique_ptr<base::CommandLine> command_line,
std::unique_ptr<SandboxedProcessLauncherDelegate> delegate,
const base::WeakPtr<ChildProcessLauncher>& child_process_launcher,
bool terminate_on_shutdown,
#if BUILDFLAG(IS_ANDROID)
bool can_use_warm_up_connection,
#endif
mojo::OutgoingInvitation mojo_invitation,
const mojo::ProcessErrorCallback& process_error_callback,
std::unique_ptr<ChildProcessLauncherFileData> file_data,
base::UnsafeSharedMemoryRegion histogram_memory_region,
base::ReadOnlySharedMemoryRegion tracing_config_memory_region)
: child_process_id_(child_process_id),
client_task_runner_(base::SequencedTaskRunner::GetCurrentDefault()),
command_line_(std::move(command_line)),
delegate_(std::move(delegate)),
child_process_launcher_(child_process_launcher),
terminate_on_shutdown_(terminate_on_shutdown),
mojo_invitation_(std::move(mojo_invitation)),
process_error_callback_(process_error_callback),
file_data_(std::move(file_data)),
#if BUILDFLAG(IS_ANDROID)
can_use_warm_up_connection_(can_use_warm_up_connection),
#endif
histogram_memory_region_(std::move(histogram_memory_region)),
tracing_config_memory_region_(std::move(tracing_config_memory_region)),
init_start_time_(base::TimeTicks::Now()) {
if (!mojo::core::GetConfiguration().is_broker_process &&
!command_line_->HasSwitch(switches::kDisableMojoBroker)) {
command_line_->AppendSwitch(switches::kDisableMojoBroker);
}
// command_line_ is always accessed from the launcher thread, so detach it
// from the client thread here.
command_line_->DetachFromCurrentSequence();
}
ChildProcessLauncherHelper::~ChildProcessLauncherHelper() {
#if BUILDFLAG(IS_CHROMEOS)
if (base::FeatureList::IsEnabled(features::kSchedQoSOnResourcedForChrome) &&
process_id_.has_value()) {
base::Process::Open(process_id_.value()).ForgetPriority();
}
#endif // BUILDFLAG(IS_CHROMEOS)
}
void ChildProcessLauncherHelper::StartLaunchOnClientThread() {
DCHECK(client_task_runner_->RunsTasksInCurrentSequence());
BeforeLaunchOnClientThread();
GetProcessLauncherTaskRunner()->PostTask(
FROM_HERE,
base::BindOnce(&ChildProcessLauncherHelper::LaunchOnLauncherThread,
this));
}
void ChildProcessLauncherHelper::LaunchOnLauncherThread() {
DCHECK(CurrentlyOnProcessLauncherTaskRunner());
// Record the delay in getting to the launcher thread.
UMA_HISTOGRAM_TIMES("MPArch.ChildProcessLauncher.PreLaunchDelay",
base::TimeTicks::Now() - init_start_time_);
#if BUILDFLAG(IS_FUCHSIA)
mojo_channel_.emplace();
#else // BUILDFLAG(IS_FUCHSIA)
mojo_named_channel_ = CreateNamedPlatformChannelOnLauncherThread();
if (!mojo_named_channel_) {
mojo_channel_.emplace();
}
#endif // BUILDFLAG(IS_FUCHSIA)
begin_launch_time_ = base::TimeTicks::Now();
if (GetProcessType() == switches::kRendererProcess &&
base::TimeTicks::IsConsistentAcrossProcesses()) {
const base::TimeDelta ticks_as_delta = begin_launch_time_.since_origin();
command_line()->AppendSwitchASCII(
switches::kRendererProcessLaunchTimeTicks,
base::NumberToString(ticks_as_delta.InMicroseconds()));
}
std::unique_ptr<FileMappedForLaunch> files_to_register = GetFilesToMap();
bool is_synchronous_launch = true;
int launch_result = LAUNCH_RESULT_FAILURE;
std::optional<base::LaunchOptions> options;
base::LaunchOptions* options_ptr = nullptr;
if (IsUsingLaunchOptions()) {
options.emplace();
options_ptr = &*options;
#if BUILDFLAG(IS_WIN)
options_ptr->elevated = delegate_->ShouldLaunchElevated();
#endif
}
// Update the command line and launch options to pass the histogram and
// field trial shared memory region handles.
PassHistogramSharedMemoryHandle(std::move(histogram_memory_region_),
command_line(), options_ptr,
files_to_register.get());
PassFieldTrialSharedMemoryHandle(command_line(), options_ptr,
files_to_register.get());
PassStartupTracingConfigSharedMemoryHandle(
std::move(tracing_config_memory_region_), command_line(), options_ptr,
files_to_register.get());
// Transfer logging switches & handles if necessary.
PassLoggingSwitches(options_ptr, command_line());
// Launch the child process.
Process process;
if (BeforeLaunchOnLauncherThread(*files_to_register, options_ptr)) {
process =
LaunchProcessOnLauncherThread(options_ptr, std::move(files_to_register),
#if BUILDFLAG(IS_ANDROID)
can_use_warm_up_connection_,
#endif
&is_synchronous_launch, &launch_result);
AfterLaunchOnLauncherThread(process, options_ptr);
}
if (is_synchronous_launch) {
// The LastError is set on the launcher thread, but needs to be transferred
// to the Client thread.
PostLaunchOnLauncherThread(std::move(process),
#if BUILDFLAG(IS_WIN)
::GetLastError(),
#endif
launch_result);
}
}
void ChildProcessLauncherHelper::PostLaunchOnLauncherThread(
ChildProcessLauncherHelper::Process process,
#if BUILDFLAG(IS_WIN)
DWORD last_error,
#endif
int launch_result) {
#if BUILDFLAG(IS_WIN)
const bool launch_elevated = delegate_->ShouldLaunchElevated();
#else
const bool launch_elevated = false;
#endif
if (mojo_channel_)
mojo_channel_->RemoteProcessLaunchAttempted();
if (process.process.IsValid()) {
RecordHistogramsOnLauncherThread(base::TimeTicks::Now() -
begin_launch_time_);
}
// Take ownership of the broker client invitation here so it's destroyed when
// we go out of scope regardless of the outcome below.
mojo::OutgoingInvitation invitation = std::move(mojo_invitation_);
if (launch_elevated) {
invitation.set_extra_flags(MOJO_SEND_INVITATION_FLAG_ELEVATED);
}
#if BUILDFLAG(IS_WIN)
if (delegate_->ShouldUseUntrustedMojoInvitation()) {
invitation.set_extra_flags(MOJO_SEND_INVITATION_FLAG_UNTRUSTED_PROCESS);
}
#endif
if (!mojo::core::GetConfiguration().is_broker_process) {
invitation.set_extra_flags(MOJO_SEND_INVITATION_FLAG_SHARE_BROKER);
}
if (process.process.IsValid()) {
#if !BUILDFLAG(IS_FUCHSIA)
if (mojo_named_channel_) {
DCHECK(!mojo_channel_);
mojo::OutgoingInvitation::Send(
std::move(invitation), base::kNullProcessHandle,
mojo_named_channel_->TakeServerEndpoint(), process_error_callback_);
} else
#endif
// Set up Mojo IPC to the new process.
{
DCHECK(mojo_channel_);
DCHECK(mojo_channel_->local_endpoint().is_valid());
mojo::OutgoingInvitation::Send(
std::move(invitation), process.process.Handle(),
mojo_channel_->TakeLocalEndpoint(), process_error_callback_);
}
}
client_task_runner_->PostTask(
FROM_HERE,
base::BindOnce(&ChildProcessLauncherHelper::PostLaunchOnClientThread,
this, std::move(process),
#if BUILDFLAG(IS_WIN)
last_error,
#endif
launch_result));
}
void ChildProcessLauncherHelper::PostLaunchOnClientThread(
ChildProcessLauncherHelper::Process process,
#if BUILDFLAG(IS_WIN)
DWORD last_error,
#endif
int error_code) {
if (child_process_launcher_) {
// Record the total launch duration.
UMA_HISTOGRAM_TIMES("MPArch.ChildProcessLauncher.Notify",
base::TimeTicks::Now() - init_start_time_);
child_process_launcher_->Notify(std::move(process),
#if BUILDFLAG(IS_WIN)
last_error,
#endif
error_code);
} else if (process.process.IsValid() && terminate_on_shutdown_) {
// Client is gone, terminate the process.
ForceNormalProcessTerminationAsync(std::move(process));
}
}
std::string ChildProcessLauncherHelper::GetProcessType() {
return command_line()->GetSwitchValueASCII(switches::kProcessType);
}
// static
void ChildProcessLauncherHelper::ForceNormalProcessTerminationAsync(
ChildProcessLauncherHelper::Process process) {
if (CurrentlyOnProcessLauncherTaskRunner()) {
ForceNormalProcessTerminationSync(std::move(process));
return;
}
// On Posix, EnsureProcessTerminated can lead to 2 seconds of sleep!
// So don't do this on the UI/IO threads.
GetProcessLauncherTaskRunner()->PostTask(
FROM_HERE,
base::BindOnce(
&ChildProcessLauncherHelper::ForceNormalProcessTerminationSync,
std::move(process)));
}
#if !BUILDFLAG(IS_WIN)
void ChildProcessLauncherHelper::PassLoggingSwitches(
base::LaunchOptions* launch_options,
base::CommandLine* cmd_line) {
const base::CommandLine& browser_command_line =
*base::CommandLine::ForCurrentProcess();
constexpr const char* kForwardSwitches[] = {
switches::kDisableLogging,
switches::kEnableLogging,
switches::kLogFile,
switches::kLoggingLevel,
switches::kV,
switches::kVModule,
};
cmd_line->CopySwitchesFrom(browser_command_line, kForwardSwitches);
}
#endif // !BUILDFLAG(IS_WIN)
} // namespace internal
// static
base::SingleThreadTaskRunner* GetProcessLauncherTaskRunner() {
#if BUILDFLAG(IS_ANDROID)
// Android specializes Launcher thread so it is accessible in java.
// Note Android never does clean shutdown, so shutdown use-after-free
// concerns are not a problem in practice.
// This process launcher thread will use the Java-side process-launching
// thread, instead of creating its own separate thread on C++ side. Note
// that means this thread will not be joined on shutdown, and may cause
// use-after-free if anything tries to access objects deleted by
// AtExitManager, such as non-leaky LazyInstance.
static base::NoDestructor<scoped_refptr<base::SingleThreadTaskRunner>>
launcher_task_runner(android::LauncherThread::GetTaskRunner());
return (*launcher_task_runner).get();
#else // BUILDFLAG(IS_ANDROID)
// TODO(http://crbug.com/820200): Investigate whether we could use
// SequencedTaskRunner on platforms other than Windows.
static base::LazyThreadPoolSingleThreadTaskRunner launcher_task_runner =
LAZY_THREAD_POOL_SINGLE_THREAD_TASK_RUNNER_INITIALIZER(
base::TaskTraits(base::MayBlock(), base::TaskPriority::USER_BLOCKING,
base::TaskShutdownBehavior::BLOCK_SHUTDOWN),
base::SingleThreadTaskRunnerThreadMode::DEDICATED);
return launcher_task_runner.Get().get();
#endif // BUILDFLAG(IS_ANDROID)
}
// static
bool CurrentlyOnProcessLauncherTaskRunner() {
return GetProcessLauncherTaskRunner()->RunsTasksInCurrentSequence();
}
} // namespace content