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platform_system_core/init/init.cpp
Bart Van Assche a75f210398 init: Make WaitToBeReaped() wait less long 
Reduce the time spent in WaitToBeReaped() by waiting for SIGCHLD instead
of waiting for 50 ms.

Bug: 308687042
Change-Id: I5e259fdd22dec68e45d27205def2fc6463c06ca3
Signed-off-by: Bart Van Assche <bvanassche@google.com>
2023-11-07 10:52:26 -08:00

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/*
* 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 <paths.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/eventfd.h>
#include <sys/mount.h>
#include <sys/signalfd.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <unistd.h>
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <sys/_system_properties.h>
#include <filesystem>
#include <fstream>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <mutex>
#include <optional>
#include <thread>
#include <vector>
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/thread_annotations.h>
#include <fs_avb/fs_avb.h>
#include <fs_mgr_vendor_overlay.h>
#include <keyutils.h>
#include <libavb/libavb.h>
#include <libgsi/libgsi.h>
#include <libsnapshot/snapshot.h>
#include <logwrap/logwrap.h>
#include <processgroup/processgroup.h>
#include <processgroup/setup.h>
#include <selinux/android.h>
#include <unwindstack/AndroidUnwinder.h>
#include "action.h"
#include "action_manager.h"
#include "action_parser.h"
#include "apex_init_util.h"
#include "epoll.h"
#include "first_stage_init.h"
#include "first_stage_mount.h"
#include "import_parser.h"
#include "keychords.h"
#include "lmkd_service.h"
#include "mount_handler.h"
#include "mount_namespace.h"
#include "property_service.h"
#include "proto_utils.h"
#include "reboot.h"
#include "reboot_utils.h"
#include "second_stage_resources.h"
#include "security.h"
#include "selabel.h"
#include "selinux.h"
#include "service.h"
#include "service_list.h"
#include "service_parser.h"
#include "sigchld_handler.h"
#include "snapuserd_transition.h"
#include "subcontext.h"
#include "system/core/init/property_service.pb.h"
#include "util.h"
#ifndef RECOVERY
#include "com_android_apex.h"
#endif // RECOVERY
using namespace std::chrono_literals;
using namespace std::string_literals;
using android::base::boot_clock;
using android::base::ConsumePrefix;
using android::base::GetProperty;
using android::base::ReadFileToString;
using android::base::SetProperty;
using android::base::StringPrintf;
using android::base::Timer;
using android::base::Trim;
using android::base::unique_fd;
using android::fs_mgr::AvbHandle;
using android::snapshot::SnapshotManager;
namespace android {
namespace init {
static int property_triggers_enabled = 0;
int sigchld_fd = -1;
static int sigterm_fd = -1;
static int property_fd = -1;
struct PendingControlMessage {
std::string message;
std::string name;
pid_t pid;
int fd;
};
static std::mutex pending_control_messages_lock;
static std::queue<PendingControlMessage> pending_control_messages;
// Init epolls various FDs to wait for various inputs. It previously waited on property changes
// with a blocking socket that contained the information related to the change, however, it was easy
// to fill that socket and deadlock the system. Now we use locks to handle the property changes
// directly in the property thread, however we still must wake the epoll to inform init that there
// is a change to process, so we use this FD. It is non-blocking, since we do not care how many
// times WakeMainInitThread() is called, only that the epoll will wake.
static int wake_main_thread_fd = -1;
static void InstallInitNotifier(Epoll* epoll) {
wake_main_thread_fd = eventfd(0, EFD_CLOEXEC);
if (wake_main_thread_fd == -1) {
PLOG(FATAL) << "Failed to create eventfd for waking init";
}
auto clear_eventfd = [] {
uint64_t counter;
TEMP_FAILURE_RETRY(read(wake_main_thread_fd, &counter, sizeof(counter)));
};
if (auto result = epoll->RegisterHandler(wake_main_thread_fd, clear_eventfd); !result.ok()) {
LOG(FATAL) << result.error();
}
}
static void WakeMainInitThread() {
uint64_t counter = 1;
TEMP_FAILURE_RETRY(write(wake_main_thread_fd, &counter, sizeof(counter)));
}
static class PropWaiterState {
public:
bool StartWaiting(const char* name, const char* value) {
auto lock = std::lock_guard{lock_};
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() {
auto lock = std::lock_guard{lock_};
ResetWaitForPropLocked();
}
void CheckAndResetWait(const std::string& name, const std::string& value) {
auto lock = std::lock_guard{lock_};
// We always record how long init waited for ueventd to tell us cold boot finished.
// If we aren't waiting on this property, it means that ueventd finished before we even
// started to wait.
if (name == kColdBootDoneProp) {
auto time_waited = waiting_for_prop_ ? waiting_for_prop_->duration().count() : 0;
std::thread([time_waited] {
SetProperty("ro.boottime.init.cold_boot_wait", std::to_string(time_waited));
}).detach();
}
if (waiting_for_prop_) {
if (wait_prop_name_ == name && wait_prop_value_ == value) {
LOG(INFO) << "Wait for property '" << wait_prop_name_ << "=" << wait_prop_value_
<< "' took " << *waiting_for_prop_;
ResetWaitForPropLocked();
WakeMainInitThread();
}
}
}
// This is not thread safe because it releases the lock when it returns, so the waiting state
// may change. However, we only use this function to prevent running commands in the main
// thread loop when we are waiting, so we do not care about false positives; only false
// negatives. StartWaiting() and this function are always called from the same thread, so false
// negatives are not possible and therefore we're okay.
bool MightBeWaiting() {
auto lock = std::lock_guard{lock_};
return static_cast<bool>(waiting_for_prop_);
}
private:
void ResetWaitForPropLocked() EXCLUSIVE_LOCKS_REQUIRED(lock_) {
wait_prop_name_.clear();
wait_prop_value_.clear();
waiting_for_prop_.reset();
}
std::mutex lock_;
GUARDED_BY(lock_) std::unique_ptr<Timer> waiting_for_prop_{nullptr};
GUARDED_BY(lock_) std::string wait_prop_name_;
GUARDED_BY(lock_) std::string wait_prop_value_;
} prop_waiter_state;
bool start_waiting_for_property(const char* name, const char* value) {
return prop_waiter_state.StartWaiting(name, value);
}
void ResetWaitForProp() {
prop_waiter_state.ResetWaitForProp();
}
static class ShutdownState {
public:
void TriggerShutdown(const std::string& command) {
// We can't call HandlePowerctlMessage() directly 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.
auto lock = std::lock_guard{shutdown_command_lock_};
shutdown_command_ = command;
do_shutdown_ = true;
WakeMainInitThread();
}
std::optional<std::string> CheckShutdown() __attribute__((warn_unused_result)) {
auto lock = std::lock_guard{shutdown_command_lock_};
if (do_shutdown_ && !IsShuttingDown()) {
do_shutdown_ = false;
return shutdown_command_;
}
return {};
}
private:
std::mutex shutdown_command_lock_;
std::string shutdown_command_ GUARDED_BY(shutdown_command_lock_);
bool do_shutdown_ = false;
} shutdown_state;
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, GetSubcontext(), std::nullopt));
parser.AddSectionParser("on", std::make_unique<ActionParser>(&action_manager, GetSubcontext()));
parser.AddSectionParser("import", std::make_unique<ImportParser>(&parser));
return parser;
}
#ifndef RECOVERY
template <typename T>
struct LibXmlErrorHandler {
T handler_;
template <typename Handler>
LibXmlErrorHandler(Handler&& handler) : handler_(std::move(handler)) {
xmlSetGenericErrorFunc(nullptr, &ErrorHandler);
}
~LibXmlErrorHandler() { xmlSetGenericErrorFunc(nullptr, nullptr); }
static void ErrorHandler(void*, const char* msg, ...) {
va_list args;
va_start(args, msg);
char* formatted;
if (vasprintf(&formatted, msg, args) >= 0) {
LOG(ERROR) << formatted;
}
free(formatted);
va_end(args);
}
};
template <typename Handler>
LibXmlErrorHandler(Handler&&) -> LibXmlErrorHandler<Handler>;
#endif // RECOVERY
// Returns a Parser that accepts scripts from APEX modules. It supports `service` and `on`.
Parser CreateApexConfigParser(ActionManager& action_manager, ServiceList& service_list) {
Parser parser;
auto subcontext = GetSubcontext();
#ifndef RECOVERY
if (subcontext) {
const auto apex_info_list_file = "/apex/apex-info-list.xml";
auto error_handler = LibXmlErrorHandler([&](const auto& error_message) {
LOG(ERROR) << "Failed to read " << apex_info_list_file << ":" << error_message;
});
const auto apex_info_list = com::android::apex::readApexInfoList(apex_info_list_file);
if (apex_info_list.has_value()) {
std::vector<std::string> subcontext_apexes;
for (const auto& info : apex_info_list->getApexInfo()) {
if (info.hasPreinstalledModulePath() &&
subcontext->PathMatchesSubcontext(info.getPreinstalledModulePath())) {
subcontext_apexes.push_back(info.getModuleName());
}
}
subcontext->SetApexList(std::move(subcontext_apexes));
}
}
#endif // RECOVERY
parser.AddSectionParser("service",
std::make_unique<ServiceParser>(&service_list, subcontext,
std::nullopt));
parser.AddSectionParser("on", std::make_unique<ActionParser>(&action_manager, subcontext));
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("/system/etc/init/hw/init.rc");
if (!parser.ParseConfig("/system/etc/init")) {
late_import_paths.emplace_back("/system/etc/init");
}
// late_import is available only in Q and earlier release. As we don't
// have system_ext in those versions, skip late_import for system_ext.
parser.ParseConfig("/system_ext/etc/init");
if (!parser.ParseConfig("/vendor/etc/init")) {
late_import_paths.emplace_back("/vendor/etc/init");
}
if (!parser.ParseConfig("/odm/etc/init")) {
late_import_paths.emplace_back("/odm/etc/init");
}
if (!parser.ParseConfig("/product/etc/init")) {
late_import_paths.emplace_back("/product/etc/init");
}
} else {
parser.ParseConfig(bootscript);
}
}
void PropertyChanged(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") {
trigger_shutdown(value);
}
if (property_triggers_enabled) {
ActionManager::GetInstance().QueuePropertyChange(name, value);
WakeMainInitThread();
}
prop_waiter_state.CheckAndResetWait(name, value);
}
static std::optional<boot_clock::time_point> HandleProcessActions() {
std::optional<boot_clock::time_point> next_process_action_time;
for (const auto& s : ServiceList::GetInstance()) {
if ((s->flags() & SVC_RUNNING) && s->timeout_period()) {
auto timeout_time = s->time_started() + *s->timeout_period();
if (boot_clock::now() > timeout_time) {
s->Timeout();
} else {
if (!next_process_action_time || timeout_time < *next_process_action_time) {
next_process_action_time = timeout_time;
}
}
}
if (!(s->flags() & SVC_RESTARTING)) continue;
auto restart_time = s->time_started() + s->restart_period();
if (boot_clock::now() > restart_time) {
if (auto result = s->Start(); !result.ok()) {
LOG(ERROR) << "Could not restart process '" << s->name() << "': " << result.error();
}
} else {
if (!next_process_action_time || restart_time < *next_process_action_time) {
next_process_action_time = restart_time;
}
}
}
return next_process_action_time;
}
static Result<void> DoControlStart(Service* service) {
return service->Start();
}
static Result<void> DoControlStop(Service* service) {
service->Stop();
return {};
}
static Result<void> DoControlRestart(Service* service) {
service->Restart();
return {};
}
int StopServicesFromApex(const std::string& apex_name) {
auto services = ServiceList::GetInstance().FindServicesByApexName(apex_name);
if (services.empty()) {
LOG(INFO) << "No service found for APEX: " << apex_name;
return 0;
}
std::set<std::string> service_names;
for (const auto& service : services) {
service_names.emplace(service->name());
}
constexpr std::chrono::milliseconds kServiceStopTimeout = 10s;
int still_running = StopServicesAndLogViolations(service_names, kServiceStopTimeout,
true /*SIGTERM*/);
// Send SIGKILL to ones that didn't terminate cleanly.
if (still_running > 0) {
still_running = StopServicesAndLogViolations(service_names, 0ms, false /*SIGKILL*/);
}
return still_running;
}
void RemoveServiceAndActionFromApex(const std::string& apex_name) {
// Remove services and actions that match apex name
ActionManager::GetInstance().RemoveActionIf([&](const std::unique_ptr<Action>& action) -> bool {
if (GetApexNameFromFileName(action->filename()) == apex_name) {
return true;
}
return false;
});
ServiceList::GetInstance().RemoveServiceIf([&](const std::unique_ptr<Service>& s) -> bool {
if (GetApexNameFromFileName(s->filename()) == apex_name) {
return true;
}
return false;
});
}
static Result<void> DoUnloadApex(const std::string& apex_name) {
if (StopServicesFromApex(apex_name) > 0) {
return Error() << "Unable to stop all service from " << apex_name;
}
RemoveServiceAndActionFromApex(apex_name);
return {};
}
static Result<void> UpdateApexLinkerConfig(const std::string& apex_name) {
// Do not invoke linkerconfig when there's no bin/ in the apex.
const std::string bin_path = "/apex/" + apex_name + "/bin";
if (access(bin_path.c_str(), R_OK) != 0) {
return {};
}
const char* linkerconfig_binary = "/apex/com.android.runtime/bin/linkerconfig";
const char* linkerconfig_target = "/linkerconfig";
const char* arguments[] = {linkerconfig_binary, "--target", linkerconfig_target, "--apex",
apex_name.c_str(), "--strict"};
if (logwrap_fork_execvp(arraysize(arguments), arguments, nullptr, false, LOG_KLOG, false,
nullptr) != 0) {
return ErrnoError() << "failed to execute linkerconfig";
}
LOG(INFO) << "Generated linker configuration for " << apex_name;
return {};
}
static Result<void> DoLoadApex(const std::string& apex_name) {
if (auto result = ParseRcScriptsFromApex(apex_name); !result.ok()) {
return result.error();
}
if (auto result = UpdateApexLinkerConfig(apex_name); !result.ok()) {
return result.error();
}
return {};
}
enum class ControlTarget {
SERVICE, // function gets called for the named service
INTERFACE, // action gets called for every service that holds this interface
};
using ControlMessageFunction = std::function<Result<void>(Service*)>;
static const std::map<std::string, ControlMessageFunction, std::less<>>& GetControlMessageMap() {
// clang-format off
static const std::map<std::string, ControlMessageFunction, std::less<>> control_message_functions = {
{"sigstop_on", [](auto* service) { service->set_sigstop(true); return Result<void>{}; }},
{"sigstop_off", [](auto* service) { service->set_sigstop(false); return Result<void>{}; }},
{"oneshot_on", [](auto* service) { service->set_oneshot(true); return Result<void>{}; }},
{"oneshot_off", [](auto* service) { service->set_oneshot(false); return Result<void>{}; }},
{"start", DoControlStart},
{"stop", DoControlStop},
{"restart", DoControlRestart},
};
// clang-format on
return control_message_functions;
}
static Result<void> HandleApexControlMessage(std::string_view action, const std::string& name,
std::string_view message) {
if (action == "load") {
return DoLoadApex(name);
} else if (action == "unload") {
return DoUnloadApex(name);
} else {
return Error() << "Unknown control msg '" << message << "'";
}
}
static bool HandleControlMessage(std::string_view message, const std::string& name,
pid_t from_pid) {
std::string cmdline_path = StringPrintf("proc/%d/cmdline", from_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";
}
auto action = message;
if (ConsumePrefix(&action, "apex_")) {
if (auto result = HandleApexControlMessage(action, name, message); !result.ok()) {
LOG(ERROR) << "Control message: Could not ctl." << message << " for '" << name
<< "' from pid: " << from_pid << " (" << process_cmdline
<< "): " << result.error();
return false;
}
LOG(INFO) << "Control message: Processed ctl." << message << " for '" << name
<< "' from pid: " << from_pid << " (" << process_cmdline << ")";
return true;
}
Service* service = nullptr;
if (ConsumePrefix(&action, "interface_")) {
service = ServiceList::GetInstance().FindInterface(name);
} else {
service = ServiceList::GetInstance().FindService(name);
}
if (service == nullptr) {
LOG(ERROR) << "Control message: Could not find '" << name << "' for ctl." << message
<< " from pid: " << from_pid << " (" << process_cmdline << ")";
return false;
}
const auto& map = GetControlMessageMap();
const auto it = map.find(action);
if (it == map.end()) {
LOG(ERROR) << "Unknown control msg '" << message << "'";
return false;
}
const auto& function = it->second;
if (auto result = function(service); !result.ok()) {
LOG(ERROR) << "Control message: Could not ctl." << message << " for '" << name
<< "' from pid: " << from_pid << " (" << process_cmdline
<< "): " << result.error();
return false;
}
LOG(INFO) << "Control message: Processed ctl." << message << " for '" << name
<< "' from pid: " << from_pid << " (" << process_cmdline << ")";
return true;
}
bool QueueControlMessage(const std::string& message, const std::string& name, pid_t pid, int fd) {
auto lock = std::lock_guard{pending_control_messages_lock};
if (pending_control_messages.size() > 100) {
LOG(ERROR) << "Too many pending control messages, dropped '" << message << "' for '" << name
<< "' from pid: " << pid;
return false;
}
pending_control_messages.push({message, name, pid, fd});
WakeMainInitThread();
return true;
}
static void HandleControlMessages() {
auto lock = std::unique_lock{pending_control_messages_lock};
// Init historically would only execute handle one property message, including control messages
// in each iteration of its main loop. We retain this behavior here to prevent starvation of
// other actions in the main loop.
if (!pending_control_messages.empty()) {
auto control_message = pending_control_messages.front();
pending_control_messages.pop();
lock.unlock();
bool success = HandleControlMessage(control_message.message, control_message.name,
control_message.pid);
uint32_t response = success ? PROP_SUCCESS : PROP_ERROR_HANDLE_CONTROL_MESSAGE;
if (control_message.fd != -1) {
TEMP_FAILURE_RETRY(send(control_message.fd, &response, sizeof(response), 0));
close(control_message.fd);
}
lock.lock();
}
// If we still have items to process, make sure we wake back up to do so.
if (!pending_control_messages.empty()) {
WakeMainInitThread();
}
}
static Result<void> wait_for_coldboot_done_action(const BuiltinArguments& args) {
if (!prop_waiter_state.StartWaiting(kColdBootDoneProp, "true")) {
LOG(FATAL) << "Could not wait for '" << kColdBootDoneProp << "'";
}
return {};
}
static Result<void> SetupCgroupsAction(const BuiltinArguments&) {
if (!CgroupsAvailable()) {
LOG(INFO) << "Cgroups support in kernel is not enabled";
return {};
}
// Have to create <CGROUPS_RC_DIR> using make_dir function
// for appropriate sepolicy to be set for it
make_dir(android::base::Dirname(CGROUPS_RC_PATH), 0711);
if (!CgroupSetup()) {
return ErrnoError() << "Failed to setup cgroups";
}
return {};
}
static void export_oem_lock_status() {
if (!android::base::GetBoolProperty("ro.oem_unlock_supported", false)) {
return;
}
SetProperty(
"ro.boot.flash.locked",
android::base::GetProperty("ro.boot.verifiedbootstate", "") == "orange" ? "0" : "1");
}
static Result<void> property_enable_triggers_action(const BuiltinArguments& args) {
/* Enable property triggers. */
property_triggers_enabled = 1;
return {};
}
static Result<void> queue_property_triggers_action(const BuiltinArguments& args) {
ActionManager::GetInstance().QueueBuiltinAction(property_enable_triggers_action, "enable_property_trigger");
ActionManager::GetInstance().QueueAllPropertyActions();
return {};
}
// 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 SetUsbController() {
static auto controller_set = false;
if (controller_set) return;
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;
SetProperty("sys.usb.controller", dp->d_name);
controller_set = true;
break;
}
}
/// Set ro.kernel.version property to contain the major.minor pair as returned
/// by uname(2).
static void SetKernelVersion() {
struct utsname uts;
unsigned int major, minor;
if ((uname(&uts) != 0) || (sscanf(uts.release, "%u.%u", &major, &minor) != 2)) {
LOG(ERROR) << "Could not parse the kernel version from uname";
return;
}
SetProperty("ro.kernel.version", android::base::StringPrintf("%u.%u", major, minor));
}
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(int signal) {
signalfd_siginfo siginfo;
const int signal_fd = signal == SIGCHLD ? sigchld_fd : sigterm_fd;
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:
LOG(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 Result<int> CreateAndRegisterSignalFd(Epoll* epoll, int signal) {
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, signal);
unique_fd signal_fd(signalfd(-1, &mask, SFD_CLOEXEC));
if (signal_fd == -1) {
return ErrnoError() << "failed to create signalfd for signal " << signal;
}
auto result = epoll->RegisterHandler(
signal_fd.get(), [signal]() { HandleSignalFd(signal); }, EPOLLIN | EPOLLPRI);
if (!result.ok()) {
return result.error();
}
return signal_fd.release();
}
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_flags = SA_NOCLDSTOP, .sa_handler = SIG_DFL };
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);
}
Result<int> cs_result = CreateAndRegisterSignalFd(epoll, SIGCHLD);
if (!cs_result.ok()) {
PLOG(FATAL) << cs_result.error();
}
sigchld_fd = cs_result.value();
Service::SetSigchldFd(sigchld_fd);
if (sigismember(&mask, SIGTERM)) {
Result<int> cs_result = CreateAndRegisterSignalFd(epoll, SIGTERM);
if (!cs_result.ok()) {
PLOG(FATAL) << cs_result.error();
}
sigterm_fd = cs_result.value();
}
}
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.ok()) {
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 UmountDebugRamdisk() {
if (umount("/debug_ramdisk") != 0) {
PLOG(ERROR) << "Failed to umount /debug_ramdisk";
}
}
static void UmountSecondStageRes() {
if (umount(kSecondStageRes) != 0) {
PLOG(ERROR) << "Failed to umount " << kSecondStageRes;
}
}
static void MountExtraFilesystems() {
#define CHECKCALL(x) \
if ((x) != 0) PLOG(FATAL) << #x " failed.";
// /apex is used to mount APEXes
CHECKCALL(mount("tmpfs", "/apex", "tmpfs", MS_NOEXEC | MS_NOSUID | MS_NODEV,
"mode=0755,uid=0,gid=0"));
if (NeedsTwoMountNamespaces()) {
// /bootstrap-apex is used to mount "bootstrap" APEXes.
CHECKCALL(mount("tmpfs", "/bootstrap-apex", "tmpfs", MS_NOEXEC | MS_NOSUID | MS_NODEV,
"mode=0755,uid=0,gid=0"));
}
// /linkerconfig is used to keep generated linker configuration
CHECKCALL(mount("tmpfs", "/linkerconfig", "tmpfs", MS_NOEXEC | MS_NOSUID | MS_NODEV,
"mode=0755,uid=0,gid=0"));
#undef CHECKCALL
}
static void RecordStageBoottimes(const boot_clock::time_point& second_stage_start_time) {
int64_t first_stage_start_time_ns = -1;
if (auto first_stage_start_time_str = getenv(kEnvFirstStageStartedAt);
first_stage_start_time_str) {
SetProperty("ro.boottime.init", first_stage_start_time_str);
android::base::ParseInt(first_stage_start_time_str, &first_stage_start_time_ns);
}
unsetenv(kEnvFirstStageStartedAt);
int64_t selinux_start_time_ns = -1;
if (auto selinux_start_time_str = getenv(kEnvSelinuxStartedAt); selinux_start_time_str) {
android::base::ParseInt(selinux_start_time_str, &selinux_start_time_ns);
}
unsetenv(kEnvSelinuxStartedAt);
if (selinux_start_time_ns == -1) return;
if (first_stage_start_time_ns == -1) return;
SetProperty("ro.boottime.init.first_stage",
std::to_string(selinux_start_time_ns - first_stage_start_time_ns));
SetProperty("ro.boottime.init.selinux",
std::to_string(second_stage_start_time.time_since_epoch().count() -
selinux_start_time_ns));
if (auto init_module_time_str = getenv(kEnvInitModuleDurationMs); init_module_time_str) {
SetProperty("ro.boottime.init.modules", init_module_time_str);
unsetenv(kEnvInitModuleDurationMs);
}
}
void SendLoadPersistentPropertiesMessage() {
auto init_message = InitMessage{};
init_message.set_load_persistent_properties(true);
if (auto result = SendMessage(property_fd, init_message); !result.ok()) {
LOG(ERROR) << "Failed to send load persistent properties message: " << result.error();
}
}
static Result<void> ConnectEarlyStageSnapuserdAction(const BuiltinArguments& args) {
auto pid = GetSnapuserdFirstStagePid();
if (!pid) {
return {};
}
auto info = GetSnapuserdFirstStageInfo();
if (auto iter = std::find(info.begin(), info.end(), "socket"s); iter == info.end()) {
// snapuserd does not support socket handoff, so exit early.
return {};
}
// Socket handoff is supported.
auto svc = ServiceList::GetInstance().FindService("snapuserd");
if (!svc) {
LOG(FATAL) << "Failed to find snapuserd service entry";
}
svc->SetShutdownCritical();
svc->SetStartedInFirstStage(*pid);
svc = ServiceList::GetInstance().FindService("snapuserd_proxy");
if (!svc) {
LOG(FATAL) << "Failed find snapuserd_proxy service entry, merge will never initiate";
}
if (!svc->MarkSocketPersistent("snapuserd")) {
LOG(FATAL) << "Could not find snapuserd socket in snapuserd_proxy service entry";
}
if (auto result = svc->Start(); !result.ok()) {
LOG(FATAL) << "Could not start snapuserd_proxy: " << result.error();
}
return {};
}
int SecondStageMain(int argc, char** argv) {
if (REBOOT_BOOTLOADER_ON_PANIC) {
InstallRebootSignalHandlers();
}
// No threads should be spin up until signalfd
// is registered. If the threads are indeed required,
// each of these threads _should_ make sure SIGCHLD signal
// is blocked. See b/223076262
boot_clock::time_point start_time = boot_clock::now();
trigger_shutdown = [](const std::string& command) { shutdown_state.TriggerShutdown(command); };
SetStdioToDevNull(argv);
InitKernelLogging(argv);
LOG(INFO) << "init second stage started!";
SelinuxSetupKernelLogging();
// Update $PATH in the case the second stage init is newer than first stage init, where it is
// first set.
if (setenv("PATH", _PATH_DEFPATH, 1) != 0) {
PLOG(FATAL) << "Could not set $PATH to '" << _PATH_DEFPATH << "' in second stage";
}
// Init should not crash because of a dependence on any other process, therefore we ignore
// SIGPIPE and handle EPIPE at the call site directly. Note that setting a signal to SIG_IGN
// is inherited across exec, but custom signal handlers are not. Since we do not want to
// ignore SIGPIPE for child processes, we set a no-op function for the signal handler instead.
{
struct sigaction action = {.sa_flags = SA_RESTART};
action.sa_handler = [](int) {};
sigaction(SIGPIPE, &action, nullptr);
}
// Set init and its forked children's oom_adj.
if (auto result =
WriteFile("/proc/1/oom_score_adj", StringPrintf("%d", DEFAULT_OOM_SCORE_ADJUST));
!result.ok()) {
LOG(ERROR) << "Unable to write " << DEFAULT_OOM_SCORE_ADJUST
<< " to /proc/1/oom_score_adj: " << result.error();
}
// 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));
// See if need to load debug props to allow adb root, when the device is unlocked.
const char* force_debuggable_env = getenv("INIT_FORCE_DEBUGGABLE");
bool load_debug_prop = false;
if (force_debuggable_env && AvbHandle::IsDeviceUnlocked()) {
load_debug_prop = "true"s == force_debuggable_env;
}
unsetenv("INIT_FORCE_DEBUGGABLE");
// Umount the debug ramdisk so property service doesn't read .prop files from there, when it
// is not meant to.
if (!load_debug_prop) {
UmountDebugRamdisk();
}
PropertyInit();
// Umount second stage resources after property service has read the .prop files.
UmountSecondStageRes();
// Umount the debug ramdisk after property service has read the .prop files when it means to.
if (load_debug_prop) {
UmountDebugRamdisk();
}
// Mount extra filesystems required during second stage init
MountExtraFilesystems();
// Now set up SELinux for second stage.
SelabelInitialize();
SelinuxRestoreContext();
Epoll epoll;
if (auto result = epoll.Open(); !result.ok()) {
PLOG(FATAL) << result.error();
}
// We always reap children before responding to the other pending functions. This is to
// prevent a race where other daemons see that a service has exited and ask init to
// start it again via ctl.start before init has reaped it.
epoll.SetFirstCallback(ReapAnyOutstandingChildren);
InstallSignalFdHandler(&epoll);
InstallInitNotifier(&epoll);
StartPropertyService(&property_fd);
// Make the time that init stages started available for bootstat to log.
RecordStageBoottimes(start_time);
// Set libavb version for Framework-only OTA match in Treble build.
if (const char* avb_version = getenv("INIT_AVB_VERSION"); avb_version != nullptr) {
SetProperty("ro.boot.avb_version", avb_version);
}
unsetenv("INIT_AVB_VERSION");
fs_mgr_vendor_overlay_mount_all();
export_oem_lock_status();
MountHandler mount_handler(&epoll);
SetUsbController();
SetKernelVersion();
const BuiltinFunctionMap& function_map = GetBuiltinFunctionMap();
Action::set_function_map(&function_map);
if (!SetupMountNamespaces()) {
PLOG(FATAL) << "SetupMountNamespaces failed";
}
InitializeSubcontext();
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();
// Make the GSI status available before scripts start running.
auto is_running = android::gsi::IsGsiRunning() ? "1" : "0";
SetProperty(gsi::kGsiBootedProp, is_running);
auto is_installed = android::gsi::IsGsiInstalled() ? "1" : "0";
SetProperty(gsi::kGsiInstalledProp, is_installed);
if (android::gsi::IsGsiRunning()) {
std::string dsu_slot;
if (android::gsi::GetActiveDsu(&dsu_slot)) {
SetProperty(gsi::kDsuSlotProp, dsu_slot);
}
}
am.QueueBuiltinAction(SetupCgroupsAction, "SetupCgroups");
am.QueueBuiltinAction(SetKptrRestrictAction, "SetKptrRestrict");
am.QueueBuiltinAction(TestPerfEventSelinuxAction, "TestPerfEventSelinux");
am.QueueBuiltinAction(ConnectEarlyStageSnapuserdAction, "ConnectEarlyStageSnapuserd");
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(SetMmapRndBitsAction, "SetMmapRndBits");
Keychords keychords;
am.QueueBuiltinAction(
[&epoll, &keychords](const BuiltinArguments& args) -> Result<void> {
for (const auto& svc : ServiceList::GetInstance()) {
keychords.Register(svc->keycodes());
}
keychords.Start(&epoll, HandleKeychord);
return {};
},
"KeychordInit");
// Trigger all the boot actions to get us started.
am.QueueEventTrigger("init");
// 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");
// Restore prio before main loop
setpriority(PRIO_PROCESS, 0, 0);
while (true) {
// By default, sleep until something happens. Do not convert far_future into
// std::chrono::milliseconds because that would trigger an overflow. The unit of boot_clock
// is 1ns.
const boot_clock::time_point far_future = boot_clock::time_point::max();
boot_clock::time_point next_action_time = far_future;
auto shutdown_command = shutdown_state.CheckShutdown();
if (shutdown_command) {
LOG(INFO) << "Got shutdown_command '" << *shutdown_command
<< "' Calling HandlePowerctlMessage()";
HandlePowerctlMessage(*shutdown_command);
}
if (!(prop_waiter_state.MightBeWaiting() || Service::is_exec_service_running())) {
am.ExecuteOneCommand();
// If there's more work to do, wake up again immediately.
if (am.HasMoreCommands()) {
next_action_time = boot_clock::now();
}
}
// Since the above code examined pending actions, no new actions must be
// queued by the code between this line and the Epoll::Wait() call below
// without calling WakeMainInitThread().
if (!IsShuttingDown()) {
auto next_process_action_time = HandleProcessActions();
// If there's a process that needs restarting, wake up in time for that.
if (next_process_action_time) {
next_action_time = std::min(next_action_time, *next_process_action_time);
}
}
std::optional<std::chrono::milliseconds> epoll_timeout;
if (next_action_time != far_future) {
epoll_timeout = std::chrono::ceil<std::chrono::milliseconds>(
std::max(next_action_time - boot_clock::now(), 0ns));
}
auto epoll_result = epoll.Wait(epoll_timeout);
if (!epoll_result.ok()) {
LOG(ERROR) << epoll_result.error();
}
if (!IsShuttingDown()) {
HandleControlMessages();
SetUsbController();
}
}
return 0;
}
} // namespace init
} // namespace android
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