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content / browser / child_process_host_impl.cc [blame]
// 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.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/342213636): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif
#include "content/browser/child_process_host_impl.h"
#include <limits>
#include <tuple>
#include "base/atomic_sequence_num.h"
#include "base/clang_profiling_buildflags.h"
#include "base/command_line.h"
#include "base/files/file.h"
#include "base/files/file_path.h"
#include "base/hash/hash.h"
#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/metrics/histogram_macros.h"
#include "base/numerics/safe_math.h"
#include "base/path_service.h"
#include "base/process/process_metrics.h"
#include "base/rand_util.h"
#include "base/synchronization/lock.h"
#include "base/task/single_thread_task_runner.h"
#include "build/build_config.h"
#include "content/common/content_constants_internal.h"
#include "content/common/pseudonymization_salt.h"
#include "content/public/browser/child_process_host_delegate.h"
#include "content/public/browser/content_browser_client.h"
#include "content/public/common/content_client.h"
#include "content/public/common/content_paths.h"
#include "content/public/common/content_switches.h"
#include "ipc/ipc.mojom.h"
#include "ipc/ipc_channel.h"
#include "ipc/ipc_channel_mojo.h"
#include "ipc/ipc_logging.h"
#include "ipc/message_filter.h"
#include "services/resource_coordinator/public/mojom/memory_instrumentation/constants.mojom.h"
#include "services/service_manager/public/cpp/interface_provider.h"
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
#include "base/linux_util.h"
#elif BUILDFLAG(IS_MAC)
#include "base/apple/foundation_util.h"
#include "content/browser/mac_helpers.h"
#endif // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
namespace {
// Global atomic to generate child process unique IDs.
base::AtomicSequenceNumber g_unique_id;
} // namespace
namespace content {
ChildProcessHost::~ChildProcessHost() = default;
// static
std::unique_ptr<ChildProcessHost> ChildProcessHost::Create(
ChildProcessHostDelegate* delegate,
IpcMode ipc_mode) {
return base::WrapUnique(new ChildProcessHostImpl(delegate, ipc_mode));
}
// static
base::FilePath ChildProcessHost::GetChildPath(int flags) {
base::FilePath child_path;
child_path = base::CommandLine::ForCurrentProcess()->GetSwitchValuePath(
switches::kBrowserSubprocessPath);
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
// Use /proc/self/exe rather than our known binary path so updates
// can't swap out the binary from underneath us.
if (child_path.empty() && flags & CHILD_ALLOW_SELF) {
child_path = base::FilePath(base::kProcSelfExe);
}
#endif
// On most platforms, the child executable is the same as the current
// executable.
if (child_path.empty()) {
base::PathService::Get(CHILD_PROCESS_EXE, &child_path);
}
#if BUILDFLAG(IS_MAC)
std::string child_base_name = child_path.BaseName().value();
if (flags != CHILD_NORMAL && base::apple::AmIBundled()) {
// This is a specialized helper, with the |child_path| at
// ../Framework.framework/Versions/X/Helpers/Chromium Helper.app/Contents/
// MacOS/Chromium Helper. Go back up to the "Helpers" directory to select
// a different variant.
child_path = child_path.DirName().DirName().DirName().DirName();
if (flags == CHILD_RENDERER) {
child_base_name += kMacHelperSuffix_renderer;
} else if (flags == CHILD_GPU) {
child_base_name += kMacHelperSuffix_gpu;
} else if (flags == CHILD_PLUGIN) {
child_base_name += kMacHelperSuffix_plugin;
} else if (flags > CHILD_EMBEDDER_FIRST) {
child_base_name +=
GetContentClient()->browser()->GetChildProcessSuffix(flags);
} else {
NOTREACHED_IN_MIGRATION();
}
child_path = child_path.Append(child_base_name + ".app")
.Append("Contents")
.Append("MacOS")
.Append(child_base_name);
}
#endif // BUILDFLAG(IS_MAC)
return child_path;
}
ChildProcessHostImpl::ChildProcessHostImpl(ChildProcessHostDelegate* delegate,
IpcMode ipc_mode)
: ipc_mode_(ipc_mode), delegate_(delegate), opening_channel_(false) {
if (ipc_mode_ == IpcMode::kLegacy) {
// In legacy mode, we only have an IPC Channel. Bind ChildProcess to a
// disconnected pipe so it quietly discards messages.
std::ignore = child_process_.BindNewPipeAndPassReceiver();
channel_ = IPC::ChannelMojo::Create(
mojo_invitation_->AttachMessagePipe(
kChildProcessReceiverAttachmentName),
IPC::Channel::MODE_SERVER, this,
base::SingleThreadTaskRunner::GetCurrentDefault(),
base::SingleThreadTaskRunner::GetCurrentDefault());
} else if (ipc_mode_ == IpcMode::kNormal) {
child_process_.Bind(mojo::PendingRemote<mojom::ChildProcess>(
mojo_invitation_->AttachMessagePipe(
kChildProcessReceiverAttachmentName),
/*version=*/0));
receiver_.Bind(mojo::PendingReceiver<mojom::ChildProcessHost>(
mojo_invitation_->AttachMessagePipe(
kChildProcessHostRemoteAttachmentName)));
receiver_.set_disconnect_handler(
base::BindOnce(&ChildProcessHostImpl::OnDisconnectedFromChildProcess,
base::Unretained(this)));
}
}
ChildProcessHostImpl::~ChildProcessHostImpl() {
// If a channel was never created than it wasn't registered and the filters
// weren't notified. For the sake of symmetry don't call the matching teardown
// functions. This is analogous to how RenderProcessHostImpl handles things.
if (!channel_) {
return;
}
#if BUILDFLAG(CONTENT_ENABLE_LEGACY_IPC)
for (auto& filter : filters_) {
filter->OnChannelClosing();
filter->OnFilterRemoved();
}
#endif
}
#if BUILDFLAG(CONTENT_ENABLE_LEGACY_IPC)
void ChildProcessHostImpl::AddFilter(IPC::MessageFilter* filter) {
filters_.push_back(filter);
if (channel_) {
filter->OnFilterAdded(channel_.get());
}
}
#endif
void ChildProcessHostImpl::BindReceiver(mojo::GenericPendingReceiver receiver) {
child_process_->BindReceiver(std::move(receiver));
}
#if BUILDFLAG(IS_CHROMEOS_ASH)
void ChildProcessHostImpl::ReinitializeLogging(
uint32_t logging_dest,
base::ScopedFD log_file_descriptor) {
auto logging_settings = mojom::LoggingSettings::New();
logging_settings->logging_dest = logging_dest;
logging_settings->log_file_descriptor =
mojo::PlatformHandle(std::move(log_file_descriptor));
child_process()->ReinitializeLogging(std::move(logging_settings));
}
#endif // BUILDFLAG(IS_CHROMEOS_ASH)
base::Process& ChildProcessHostImpl::GetPeerProcess() {
if (!peer_process_.IsValid()) {
const base::Process& process = delegate_->GetProcess();
if (process.IsValid()) {
peer_process_ = base::Process::OpenWithExtraPrivileges(process.Pid());
if (!peer_process_.IsValid()) {
peer_process_ = process.Duplicate();
}
DCHECK(peer_process_.IsValid());
}
}
return peer_process_;
}
void ChildProcessHostImpl::ForceShutdown() {
child_process_->ProcessShutdown();
}
std::optional<mojo::OutgoingInvitation>&
ChildProcessHostImpl::GetMojoInvitation() {
return mojo_invitation_;
}
void ChildProcessHostImpl::CreateChannelMojo() {
// If in legacy mode, |channel_| is already initialized by the constructor
// not bound through the ChildProcess API.
if (ipc_mode_ != IpcMode::kLegacy) {
DCHECK(!channel_);
DCHECK_EQ(ipc_mode_, IpcMode::kNormal);
DCHECK(child_process_);
mojo::ScopedMessagePipeHandle bootstrap =
mojo_invitation_->AttachMessagePipe(kLegacyIpcBootstrapAttachmentName);
channel_ = IPC::ChannelMojo::Create(
std::move(bootstrap), IPC::Channel::MODE_SERVER, this,
base::SingleThreadTaskRunner::GetCurrentDefault(),
base::SingleThreadTaskRunner::GetCurrentDefault());
}
DCHECK(channel_);
// Since we're initializing a legacy IPC Channel, we will use its connection
// status to monitor child process lifetime instead of using the status of the
// `receiver_` endpoint.
if (receiver_.is_bound()) {
receiver_.set_disconnect_handler(base::NullCallback());
}
bool initialized = InitChannel();
DCHECK(initialized);
}
bool ChildProcessHostImpl::InitChannel() {
if (!channel_->Connect()) {
return false;
}
#if BUILDFLAG(CONTENT_ENABLE_LEGACY_IPC)
for (auto& filter : filters_) {
filter->OnFilterAdded(channel_.get());
}
#endif
delegate_->OnChannelInitialized(channel_.get());
// Make sure these messages get sent first.
#if BUILDFLAG(IPC_MESSAGE_LOG_ENABLED)
bool enabled = IPC::Logging::GetInstance()->Enabled();
child_process_->SetIPCLoggingEnabled(enabled);
#endif
opening_channel_ = true;
return true;
}
void ChildProcessHostImpl::OnDisconnectedFromChildProcess() {
if (channel_) {
opening_channel_ = false;
delegate_->OnChannelError();
#if BUILDFLAG(CONTENT_ENABLE_LEGACY_IPC)
for (auto& filter : filters_) {
filter->OnChannelError();
}
#endif
}
// This will delete host_, which will also destroy this!
delegate_->OnChildDisconnected();
}
bool ChildProcessHostImpl::IsChannelOpening() {
return opening_channel_;
}
bool ChildProcessHostImpl::Send(IPC::Message* message) {
if (!channel_) {
delete message;
return false;
}
return channel_->Send(message);
}
// static
int ChildProcessHost::GenerateChildProcessUniqueId() {
// This function must be threadsafe.
//
// Historically, this function returned ids started with 1, so in several
// places in the code a value of 0 (rather than kInvalidUniqueID) was used as
// an invalid value. So we retain those semantics.
int id = g_unique_id.GetNext() + 1;
CHECK_NE(0, id);
CHECK_NE(kInvalidUniqueID, id);
return id;
}
uint64_t ChildProcessHostImpl::ChildProcessUniqueIdToTracingProcessId(
int child_process_id) {
// In single process mode, all the children are hosted in the same process,
// therefore the generated memory dump guids should not be conditioned by the
// child process id. The clients need not be aware of SPM and the conversion
// takes care of the SPM special case while translating child process ids to
// tracing process ids.
if (base::CommandLine::ForCurrentProcess()->HasSwitch(
switches::kSingleProcess)) {
return memory_instrumentation::mojom::kServiceTracingProcessId;
}
// The hash value is incremented so that the tracing id is never equal to
// MemoryDumpManager::kInvalidTracingProcessId.
return static_cast<uint64_t>(
base::PersistentHash(base::byte_span_from_ref(child_process_id))) +
1;
}
void ChildProcessHostImpl::Ping(PingCallback callback) {
std::move(callback).Run();
}
void ChildProcessHostImpl::BindHostReceiver(
mojo::GenericPendingReceiver receiver) {
delegate_->BindHostReceiver(std::move(receiver));
}
bool ChildProcessHostImpl::OnMessageReceived(const IPC::Message& msg) {
#if BUILDFLAG(CONTENT_ENABLE_LEGACY_IPC)
#if BUILDFLAG(IPC_MESSAGE_LOG_ENABLED)
IPC::Logging* logger = IPC::Logging::GetInstance();
if (msg.type() == IPC_LOGGING_ID) {
logger->OnReceivedLoggingMessage(msg);
return true;
}
if (logger->Enabled()) {
logger->OnPreDispatchMessage(msg);
}
#endif // IPC_MESSAGE_LOG_ENABLED
bool handled = false;
for (auto& filter : filters_) {
if (filter->OnMessageReceived(msg)) {
handled = true;
break;
}
}
if (!handled) {
handled = delegate_->OnMessageReceived(msg);
}
#if BUILDFLAG(IPC_MESSAGE_LOG_ENABLED)
if (logger->Enabled()) {
logger->OnPostDispatchMessage(msg);
}
#endif // IPC_MESSAGE_LOG_ENABLED
return handled;
#else
return false;
#endif // CONTENT_ENABLE_LEGACY_IPC
}
void ChildProcessHostImpl::OnChannelConnected(int32_t peer_pid) {
// Propagate the pseudonymization salt to all the child processes.
//
// Doing this as the first step in this method helps to minimize scenarios
// where child process runs code that depends on the pseudonymization salt
// before it has been set. See also https://crbug.com/1479308#c5
//
// TODO(dullweber, lukasza): Figure out if it is possible to reset the salt
// at a regular interval (on the order of hours?). The browser would need
// to be responsible for 1) deciding when the refresh happens and 2) pushing
// the updated salt to all the child processes.
child_process_->SetPseudonymizationSalt(GetPseudonymizationSalt());
// We ignore the `peer_pid` argument, which ultimately comes over IPC from the
// remote process, in favor of the PID already known by the browser after
// launching the process. This is partly because IPC Channel is being phased
// out and some process types no longer use it, but also because there's
// really no need to get this information from the child process when we
// already have it.
//
// TODO(crbug.com/41256971): Remove the peer_pid argument altogether from
// IPC::Listener::OnChannelConnected.
const base::Process& peer_process = GetPeerProcess();
base::ProcessId pid =
peer_process.IsValid() ? peer_process.Pid() : base::GetCurrentProcId();
opening_channel_ = false;
delegate_->OnChannelConnected(pid);
#if BUILDFLAG(CONTENT_ENABLE_LEGACY_IPC)
for (auto& filter : filters_) {
filter->OnChannelConnected(pid);
}
#endif
}
void ChildProcessHostImpl::OnChannelError() {
OnDisconnectedFromChildProcess();
}
void ChildProcessHostImpl::OnBadMessageReceived(const IPC::Message& message) {
delegate_->OnBadMessageReceived(message);
}
#if BUILDFLAG(CLANG_PROFILING_INSIDE_SANDBOX)
void ChildProcessHostImpl::DumpProfilingData(base::OnceClosure callback) {
child_process_->WriteClangProfilingProfile(std::move(callback));
}
void ChildProcessHostImpl::SetProfilingFile(base::File file) {
child_process_->SetProfilingFile(std::move(file));
}
#endif
#if BUILDFLAG(IS_ANDROID)
// Notifies the child process of memory pressure level.
void ChildProcessHostImpl::NotifyMemoryPressureToChildProcess(
base::MemoryPressureListener::MemoryPressureLevel level) {
child_process()->OnMemoryPressure(level);
}
#endif
void ChildProcessHostImpl::SetBatterySaverMode(
bool battery_saver_mode_enabled) {
child_process()->SetBatterySaverMode(battery_saver_mode_enabled);
}
} // namespace content