android_system_core/init/init.cpp
Martijn Coenen 62e985a954 init: Allow restricted use of binder.
Allow init to use binder, but in a restricted way:
- No binder threadpool
- Other processes can't initiate calls to init
- No death recipients

This change adds libbinder/libutils and calls into ProcessState,
which also calls into the kernel driver and sets up state there.
No other binder calls are made, so that we can let this soak for
a while to see if there any bad side effects of just loading
these libraries and initializing the kernel driver.

This introduces about 120kB of additional memory usage (PSS),
mostly due to pulling in libbinder and libutils and the private
state they have.

We also don't include these libraries in the recovery version of
init, because space on the recovery partition is limited.

Bug: 112684055
Test: device still boots, /d/binder/proc/1 shows init state
Change-Id: I972b1eebdb16337f52e20d1f614e3a0dce0f06d2
2018-09-07 15:47:21 +02:00

749 lines
25 KiB
C++

/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "init.h"
#include <dirent.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/signalfd.h>
#include <sys/types.h>
#include <unistd.h>
#include <map>
#include <memory>
#include <optional>
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <cutils/android_reboot.h>
#include <keyutils.h>
#include <libavb/libavb.h>
#ifndef RECOVERY
#include <binder/ProcessState.h>
#endif
#include "action_parser.h"
#include "epoll.h"
#include "first_stage_mount.h"
#include "import_parser.h"
#include "keychords.h"
#include "property_service.h"
#include "reboot.h"
#include "reboot_utils.h"
#include "security.h"
#include "selinux.h"
#include "sigchld_handler.h"
#include "ueventd.h"
#include "util.h"
using namespace std::chrono_literals;
using namespace std::string_literals;
using android::base::boot_clock;
using android::base::GetProperty;
using android::base::ReadFileToString;
using android::base::StringPrintf;
using android::base::Timer;
using android::base::Trim;
namespace android {
namespace init {
static int property_triggers_enabled = 0;
static char qemu[32];
std::string default_console = "/dev/console";
static int signal_fd = -1;
static std::unique_ptr<Timer> waiting_for_prop(nullptr);
static std::string wait_prop_name;
static std::string wait_prop_value;
static bool shutting_down;
static std::string shutdown_command;
static bool do_shutdown = false;
std::vector<std::string> late_import_paths;
static std::vector<Subcontext>* subcontexts;
void DumpState() {
ServiceList::GetInstance().DumpState();
ActionManager::GetInstance().DumpState();
}
Parser CreateParser(ActionManager& action_manager, ServiceList& service_list) {
Parser parser;
parser.AddSectionParser("service", std::make_unique<ServiceParser>(&service_list, subcontexts));
parser.AddSectionParser("on", std::make_unique<ActionParser>(&action_manager, subcontexts));
parser.AddSectionParser("import", std::make_unique<ImportParser>(&parser));
return parser;
}
static void LoadBootScripts(ActionManager& action_manager, ServiceList& service_list) {
Parser parser = CreateParser(action_manager, service_list);
std::string bootscript = GetProperty("ro.boot.init_rc", "");
if (bootscript.empty()) {
parser.ParseConfig("/init.rc");
if (!parser.ParseConfig("/system/etc/init")) {
late_import_paths.emplace_back("/system/etc/init");
}
if (!parser.ParseConfig("/product/etc/init")) {
late_import_paths.emplace_back("/product/etc/init");
}
if (!parser.ParseConfig("/product_services/etc/init")) {
late_import_paths.emplace_back("/product_services/etc/init");
}
if (!parser.ParseConfig("/odm/etc/init")) {
late_import_paths.emplace_back("/odm/etc/init");
}
if (!parser.ParseConfig("/vendor/etc/init")) {
late_import_paths.emplace_back("/vendor/etc/init");
}
} else {
parser.ParseConfig(bootscript);
}
}
bool start_waiting_for_property(const char *name, const char *value)
{
if (waiting_for_prop) {
return false;
}
if (GetProperty(name, "") != value) {
// Current property value is not equal to expected value
wait_prop_name = name;
wait_prop_value = value;
waiting_for_prop.reset(new Timer());
} else {
LOG(INFO) << "start_waiting_for_property(\""
<< name << "\", \"" << value << "\"): already set";
}
return true;
}
void ResetWaitForProp() {
wait_prop_name.clear();
wait_prop_value.clear();
waiting_for_prop.reset();
}
void property_changed(const std::string& name, const std::string& value) {
// If the property is sys.powerctl, we bypass the event queue and immediately handle it.
// This is to ensure that init will always and immediately shutdown/reboot, regardless of
// if there are other pending events to process or if init is waiting on an exec service or
// waiting on a property.
// In non-thermal-shutdown case, 'shutdown' trigger will be fired to let device specific
// commands to be executed.
if (name == "sys.powerctl") {
// Despite the above comment, we can't call HandlePowerctlMessage() in this function,
// because it modifies the contents of the action queue, which can cause the action queue
// to get into a bad state if this function is called from a command being executed by the
// action queue. Instead we set this flag and ensure that shutdown happens before the next
// command is run in the main init loop.
// TODO: once property service is removed from init, this will never happen from a builtin,
// but rather from a callback from the property service socket, in which case this hack can
// go away.
shutdown_command = value;
do_shutdown = true;
}
if (property_triggers_enabled) ActionManager::GetInstance().QueuePropertyChange(name, value);
if (waiting_for_prop) {
if (wait_prop_name == name && wait_prop_value == value) {
LOG(INFO) << "Wait for property took " << *waiting_for_prop;
ResetWaitForProp();
}
}
}
static std::optional<boot_clock::time_point> RestartProcesses() {
std::optional<boot_clock::time_point> next_process_restart_time;
for (const auto& s : ServiceList::GetInstance()) {
if (!(s->flags() & SVC_RESTARTING)) continue;
auto restart_time = s->time_started() + 5s;
if (boot_clock::now() > restart_time) {
if (auto result = s->Start(); !result) {
LOG(ERROR) << "Could not restart process '" << s->name() << "': " << result.error();
}
} else {
if (!next_process_restart_time || restart_time < *next_process_restart_time) {
next_process_restart_time = restart_time;
}
}
}
return next_process_restart_time;
}
static Result<Success> DoControlStart(Service* service) {
return service->Start();
}
static Result<Success> DoControlStop(Service* service) {
service->Stop();
return Success();
}
static Result<Success> DoControlRestart(Service* service) {
service->Restart();
return Success();
}
enum class ControlTarget {
SERVICE, // function gets called for the named service
INTERFACE, // action gets called for every service that holds this interface
};
struct ControlMessageFunction {
ControlTarget target;
std::function<Result<Success>(Service*)> action;
};
static const std::map<std::string, ControlMessageFunction>& get_control_message_map() {
// clang-format off
static const std::map<std::string, ControlMessageFunction> control_message_functions = {
{"sigstop_on", {ControlTarget::SERVICE,
[](auto* service) { service->set_sigstop(true); return Success(); }}},
{"sigstop_off", {ControlTarget::SERVICE,
[](auto* service) { service->set_sigstop(false); return Success(); }}},
{"start", {ControlTarget::SERVICE, DoControlStart}},
{"stop", {ControlTarget::SERVICE, DoControlStop}},
{"restart", {ControlTarget::SERVICE, DoControlRestart}},
{"interface_start", {ControlTarget::INTERFACE, DoControlStart}},
{"interface_stop", {ControlTarget::INTERFACE, DoControlStop}},
{"interface_restart", {ControlTarget::INTERFACE, DoControlRestart}},
};
// clang-format on
return control_message_functions;
}
void HandleControlMessage(const std::string& msg, const std::string& name, pid_t pid) {
const auto& map = get_control_message_map();
const auto it = map.find(msg);
if (it == map.end()) {
LOG(ERROR) << "Unknown control msg '" << msg << "'";
return;
}
std::string cmdline_path = StringPrintf("proc/%d/cmdline", pid);
std::string process_cmdline;
if (ReadFileToString(cmdline_path, &process_cmdline)) {
std::replace(process_cmdline.begin(), process_cmdline.end(), '\0', ' ');
process_cmdline = Trim(process_cmdline);
} else {
process_cmdline = "unknown process";
}
LOG(INFO) << "Received control message '" << msg << "' for '" << name << "' from pid: " << pid
<< " (" << process_cmdline << ")";
const ControlMessageFunction& function = it->second;
Service* svc = nullptr;
switch (function.target) {
case ControlTarget::SERVICE:
svc = ServiceList::GetInstance().FindService(name);
break;
case ControlTarget::INTERFACE:
svc = ServiceList::GetInstance().FindInterface(name);
break;
default:
LOG(ERROR) << "Invalid function target from static map key '" << msg << "': "
<< static_cast<std::underlying_type<ControlTarget>::type>(function.target);
return;
}
if (svc == nullptr) {
LOG(ERROR) << "Could not find '" << name << "' for ctl." << msg;
return;
}
if (auto result = function.action(svc); !result) {
LOG(ERROR) << "Could not ctl." << msg << " for '" << name << "': " << result.error();
}
}
static Result<Success> wait_for_coldboot_done_action(const BuiltinArguments& args) {
Timer t;
LOG(VERBOSE) << "Waiting for " COLDBOOT_DONE "...";
// Historically we had a 1s timeout here because we weren't otherwise
// tracking boot time, and many OEMs made their sepolicy regular
// expressions too expensive (http://b/19899875).
// Now we're tracking boot time, just log the time taken to a system
// property. We still panic if it takes more than a minute though,
// because any build that slow isn't likely to boot at all, and we'd
// rather any test lab devices fail back to the bootloader.
if (wait_for_file(COLDBOOT_DONE, 60s) < 0) {
LOG(FATAL) << "Timed out waiting for " COLDBOOT_DONE;
}
property_set("ro.boottime.init.cold_boot_wait", std::to_string(t.duration().count()));
return Success();
}
static Result<Success> console_init_action(const BuiltinArguments& args) {
std::string console = GetProperty("ro.boot.console", "");
if (!console.empty()) {
default_console = "/dev/" + console;
}
return Success();
}
static void import_kernel_nv(const std::string& key, const std::string& value, bool for_emulator) {
if (key.empty()) return;
if (for_emulator) {
// In the emulator, export any kernel option with the "ro.kernel." prefix.
property_set("ro.kernel." + key, value);
return;
}
if (key == "qemu") {
strlcpy(qemu, value.c_str(), sizeof(qemu));
} else if (android::base::StartsWith(key, "androidboot.")) {
property_set("ro.boot." + key.substr(12), value);
}
}
static void export_oem_lock_status() {
if (!android::base::GetBoolProperty("ro.oem_unlock_supported", false)) {
return;
}
std::string value = GetProperty("ro.boot.verifiedbootstate", "");
if (!value.empty()) {
property_set("ro.boot.flash.locked", value == "orange" ? "0" : "1");
}
}
static void export_kernel_boot_props() {
constexpr const char* UNSET = "";
struct {
const char *src_prop;
const char *dst_prop;
const char *default_value;
} prop_map[] = {
{ "ro.boot.serialno", "ro.serialno", UNSET, },
{ "ro.boot.mode", "ro.bootmode", "unknown", },
{ "ro.boot.baseband", "ro.baseband", "unknown", },
{ "ro.boot.bootloader", "ro.bootloader", "unknown", },
{ "ro.boot.hardware", "ro.hardware", "unknown", },
{ "ro.boot.revision", "ro.revision", "0", },
};
for (const auto& prop : prop_map) {
std::string value = GetProperty(prop.src_prop, prop.default_value);
if (value != UNSET)
property_set(prop.dst_prop, value);
}
}
static void process_kernel_dt() {
if (!is_android_dt_value_expected("compatible", "android,firmware")) {
return;
}
std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(get_android_dt_dir().c_str()), closedir);
if (!dir) return;
std::string dt_file;
struct dirent *dp;
while ((dp = readdir(dir.get())) != NULL) {
if (dp->d_type != DT_REG || !strcmp(dp->d_name, "compatible") || !strcmp(dp->d_name, "name")) {
continue;
}
std::string file_name = get_android_dt_dir() + dp->d_name;
android::base::ReadFileToString(file_name, &dt_file);
std::replace(dt_file.begin(), dt_file.end(), ',', '.');
property_set("ro.boot."s + dp->d_name, dt_file);
}
}
static void process_kernel_cmdline() {
// The first pass does the common stuff, and finds if we are in qemu.
// The second pass is only necessary for qemu to export all kernel params
// as properties.
import_kernel_cmdline(false, import_kernel_nv);
if (qemu[0]) import_kernel_cmdline(true, import_kernel_nv);
}
static Result<Success> property_enable_triggers_action(const BuiltinArguments& args) {
/* Enable property triggers. */
property_triggers_enabled = 1;
return Success();
}
static Result<Success> queue_property_triggers_action(const BuiltinArguments& args) {
ActionManager::GetInstance().QueueBuiltinAction(property_enable_triggers_action, "enable_property_trigger");
ActionManager::GetInstance().QueueAllPropertyActions();
return Success();
}
static Result<Success> InitBinder(const BuiltinArguments& args) {
// init's use of binder is very limited. init cannot:
// - have any binder threads
// - receive incoming binder calls
// - pass local binder services to remote processes
// - use death recipients
// The main supported usecases are:
// - notifying other daemons (oneway calls only)
// - retrieving data that is necessary to boot
// Also, binder can't be used by recovery.
#ifndef RECOVERY
android::ProcessState::self()->setThreadPoolMaxThreadCount(0);
#endif
return Success();
}
// Set the UDC controller for the ConfigFS USB Gadgets.
// Read the UDC controller in use from "/sys/class/udc".
// In case of multiple UDC controllers select the first one.
static void set_usb_controller() {
std::unique_ptr<DIR, decltype(&closedir)>dir(opendir("/sys/class/udc"), closedir);
if (!dir) return;
dirent* dp;
while ((dp = readdir(dir.get())) != nullptr) {
if (dp->d_name[0] == '.') continue;
property_set("sys.usb.controller", dp->d_name);
break;
}
}
static void HandleSigtermSignal(const signalfd_siginfo& siginfo) {
if (siginfo.ssi_pid != 0) {
// Drop any userspace SIGTERM requests.
LOG(DEBUG) << "Ignoring SIGTERM from pid " << siginfo.ssi_pid;
return;
}
HandlePowerctlMessage("shutdown,container");
}
static void HandleSignalFd() {
signalfd_siginfo siginfo;
ssize_t bytes_read = TEMP_FAILURE_RETRY(read(signal_fd, &siginfo, sizeof(siginfo)));
if (bytes_read != sizeof(siginfo)) {
PLOG(ERROR) << "Failed to read siginfo from signal_fd";
return;
}
switch (siginfo.ssi_signo) {
case SIGCHLD:
ReapAnyOutstandingChildren();
break;
case SIGTERM:
HandleSigtermSignal(siginfo);
break;
default:
PLOG(ERROR) << "signal_fd: received unexpected signal " << siginfo.ssi_signo;
break;
}
}
static void UnblockSignals() {
const struct sigaction act { .sa_handler = SIG_DFL };
sigaction(SIGCHLD, &act, nullptr);
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, SIGCHLD);
sigaddset(&mask, SIGTERM);
if (sigprocmask(SIG_UNBLOCK, &mask, nullptr) == -1) {
PLOG(FATAL) << "failed to unblock signals for PID " << getpid();
}
}
static void InstallSignalFdHandler(Epoll* epoll) {
// Applying SA_NOCLDSTOP to a defaulted SIGCHLD handler prevents the signalfd from receiving
// SIGCHLD when a child process stops or continues (b/77867680#comment9).
const struct sigaction act { .sa_handler = SIG_DFL, .sa_flags = SA_NOCLDSTOP };
sigaction(SIGCHLD, &act, nullptr);
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, SIGCHLD);
if (!IsRebootCapable()) {
// If init does not have the CAP_SYS_BOOT capability, it is running in a container.
// In that case, receiving SIGTERM will cause the system to shut down.
sigaddset(&mask, SIGTERM);
}
if (sigprocmask(SIG_BLOCK, &mask, nullptr) == -1) {
PLOG(FATAL) << "failed to block signals";
}
// Register a handler to unblock signals in the child processes.
const int result = pthread_atfork(nullptr, nullptr, &UnblockSignals);
if (result != 0) {
LOG(FATAL) << "Failed to register a fork handler: " << strerror(result);
}
signal_fd = signalfd(-1, &mask, SFD_CLOEXEC);
if (signal_fd == -1) {
PLOG(FATAL) << "failed to create signalfd";
}
if (auto result = epoll->RegisterHandler(signal_fd, HandleSignalFd); !result) {
LOG(FATAL) << result.error();
}
}
void HandleKeychord(const std::vector<int>& keycodes) {
// Only handle keychords if adb is enabled.
std::string adb_enabled = android::base::GetProperty("init.svc.adbd", "");
if (adb_enabled != "running") {
LOG(WARNING) << "Not starting service for keychord " << android::base::Join(keycodes, ' ')
<< " because ADB is disabled";
return;
}
auto found = false;
for (const auto& service : ServiceList::GetInstance()) {
auto svc = service.get();
if (svc->keycodes() == keycodes) {
found = true;
LOG(INFO) << "Starting service '" << svc->name() << "' from keychord "
<< android::base::Join(keycodes, ' ');
if (auto result = svc->Start(); !result) {
LOG(ERROR) << "Could not start service '" << svc->name() << "' from keychord "
<< android::base::Join(keycodes, ' ') << ": " << result.error();
}
}
}
if (!found) {
LOG(ERROR) << "Service for keychord " << android::base::Join(keycodes, ' ') << " not found";
}
}
static void InitAborter(const char* abort_message) {
// When init forks, it continues to use this aborter for LOG(FATAL), but we want children to
// simply abort instead of trying to reboot the system.
if (getpid() != 1) {
android::base::DefaultAborter(abort_message);
return;
}
RebootSystem(ANDROID_RB_RESTART2, "bootloader");
}
static void InitKernelLogging(char* argv[]) {
// Make stdin/stdout/stderr all point to /dev/null.
int fd = open("/sys/fs/selinux/null", O_RDWR);
if (fd == -1) {
int saved_errno = errno;
android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter);
errno = saved_errno;
PLOG(FATAL) << "Couldn't open /sys/fs/selinux/null";
}
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
if (fd > 2) close(fd);
android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter);
}
int main(int argc, char** argv) {
if (!strcmp(basename(argv[0]), "ueventd")) {
return ueventd_main(argc, argv);
}
if (argc > 1 && !strcmp(argv[1], "subcontext")) {
android::base::InitLogging(argv, &android::base::KernelLogger);
const BuiltinFunctionMap function_map;
return SubcontextMain(argc, argv, &function_map);
}
if (REBOOT_BOOTLOADER_ON_PANIC) {
InstallRebootSignalHandlers();
}
InitKernelLogging(argv);
LOG(INFO) << "init second stage started!";
// Set up a session keyring that all processes will have access to. It
// will hold things like FBE encryption keys. No process should override
// its session keyring.
keyctl_get_keyring_ID(KEY_SPEC_SESSION_KEYRING, 1);
// Indicate that booting is in progress to background fw loaders, etc.
close(open("/dev/.booting", O_WRONLY | O_CREAT | O_CLOEXEC, 0000));
property_init();
// If arguments are passed both on the command line and in DT,
// properties set in DT always have priority over the command-line ones.
process_kernel_dt();
process_kernel_cmdline();
// Propagate the kernel variables to internal variables
// used by init as well as the current required properties.
export_kernel_boot_props();
// Make the time that init started available for bootstat to log.
property_set("ro.boottime.init", getenv("INIT_STARTED_AT"));
property_set("ro.boottime.init.selinux", getenv("INIT_SELINUX_TOOK"));
// Set libavb version for Framework-only OTA match in Treble build.
const char* avb_version = getenv("INIT_AVB_VERSION");
if (avb_version) property_set("ro.boot.avb_version", avb_version);
// Clean up our environment.
unsetenv("INIT_STARTED_AT");
unsetenv("INIT_SELINUX_TOOK");
unsetenv("INIT_AVB_VERSION");
// Now set up SELinux for second stage.
SelinuxSetupKernelLogging();
SelabelInitialize();
SelinuxRestoreContext();
Epoll epoll;
if (auto result = epoll.Open(); !result) {
PLOG(FATAL) << result.error();
}
InstallSignalFdHandler(&epoll);
property_load_boot_defaults();
export_oem_lock_status();
StartPropertyService(&epoll);
set_usb_controller();
const BuiltinFunctionMap function_map;
Action::set_function_map(&function_map);
subcontexts = InitializeSubcontexts();
ActionManager& am = ActionManager::GetInstance();
ServiceList& sm = ServiceList::GetInstance();
LoadBootScripts(am, sm);
// Turning this on and letting the INFO logging be discarded adds 0.2s to
// Nexus 9 boot time, so it's disabled by default.
if (false) DumpState();
am.QueueEventTrigger("early-init");
// Queue an action that waits for coldboot done so we know ueventd has set up all of /dev...
am.QueueBuiltinAction(wait_for_coldboot_done_action, "wait_for_coldboot_done");
// ... so that we can start queuing up actions that require stuff from /dev.
am.QueueBuiltinAction(MixHwrngIntoLinuxRngAction, "MixHwrngIntoLinuxRng");
am.QueueBuiltinAction(SetMmapRndBitsAction, "SetMmapRndBits");
am.QueueBuiltinAction(SetKptrRestrictAction, "SetKptrRestrict");
Keychords keychords;
am.QueueBuiltinAction(
[&epoll, &keychords](const BuiltinArguments& args) -> Result<Success> {
for (const auto& svc : ServiceList::GetInstance()) {
keychords.Register(svc->keycodes());
}
keychords.Start(&epoll, HandleKeychord);
return Success();
},
"KeychordInit");
am.QueueBuiltinAction(console_init_action, "console_init");
// Trigger all the boot actions to get us started.
am.QueueEventTrigger("init");
// Repeat mix_hwrng_into_linux_rng in case /dev/hw_random or /dev/random
// wasn't ready immediately after wait_for_coldboot_done
am.QueueBuiltinAction(MixHwrngIntoLinuxRngAction, "MixHwrngIntoLinuxRng");
// Initialize binder before bringing up other system services
am.QueueBuiltinAction(InitBinder, "InitBinder");
// Don't mount filesystems or start core system services in charger mode.
std::string bootmode = GetProperty("ro.bootmode", "");
if (bootmode == "charger") {
am.QueueEventTrigger("charger");
} else {
am.QueueEventTrigger("late-init");
}
// Run all property triggers based on current state of the properties.
am.QueueBuiltinAction(queue_property_triggers_action, "queue_property_triggers");
while (true) {
// By default, sleep until something happens.
auto epoll_timeout = std::optional<std::chrono::milliseconds>{};
if (do_shutdown && !shutting_down) {
do_shutdown = false;
if (HandlePowerctlMessage(shutdown_command)) {
shutting_down = true;
}
}
if (!(waiting_for_prop || Service::is_exec_service_running())) {
am.ExecuteOneCommand();
}
if (!(waiting_for_prop || Service::is_exec_service_running())) {
if (!shutting_down) {
auto next_process_restart_time = RestartProcesses();
// If there's a process that needs restarting, wake up in time for that.
if (next_process_restart_time) {
epoll_timeout = std::chrono::ceil<std::chrono::milliseconds>(
*next_process_restart_time - boot_clock::now());
if (*epoll_timeout < 0ms) epoll_timeout = 0ms;
}
}
// If there's more work to do, wake up again immediately.
if (am.HasMoreCommands()) epoll_timeout = 0ms;
}
if (auto result = epoll.Wait(epoll_timeout); !result) {
LOG(ERROR) << result.error();
}
}
return 0;
}
} // namespace init
} // namespace android