unplugged-system/external/cronet/components/metrics/clean_exit_beacon.cc

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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/metrics/clean_exit_beacon.h"
#include <algorithm>
#include <memory>
#include <utility>
#include "base/check_op.h"
#include "base/command_line.h"
#include "base/files/file_util.h"
#include "base/json/json_file_value_serializer.h"
#include "base/json/json_string_value_serializer.h"
#include "base/logging.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_macros.h"
#include "base/path_service.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "base/threading/thread_restrictions.h"
#include "build/build_config.h"
#include "components/metrics/metrics_pref_names.h"
#include "components/prefs/pref_registry_simple.h"
#include "components/prefs/pref_service.h"
#include "components/variations/pref_names.h"
#include "components/variations/variations_switches.h"
#if BUILDFLAG(IS_WIN)
#include <windows.h>
#include "base/strings/string_util_win.h"
#include "base/strings/utf_string_conversions.h"
#include "base/win/registry.h"
#endif
namespace metrics {
namespace {
using ::variations::prefs::kVariationsCrashStreak;
// Denotes whether Chrome should perform clean shutdown steps: signaling that
// Chrome is exiting cleanly and then CHECKing that is has shutdown cleanly.
// This may be modified by SkipCleanShutdownStepsForTesting().
bool g_skip_clean_shutdown_steps = false;
#if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_IOS)
// Records the the combined state of two distinct beacons' values in a
// histogram.
void RecordBeaconConsistency(
absl::optional<bool> beacon_file_beacon_value,
absl::optional<bool> platform_specific_beacon_value) {
CleanExitBeaconConsistency consistency =
CleanExitBeaconConsistency::kDirtyDirty;
if (!beacon_file_beacon_value) {
if (!platform_specific_beacon_value) {
consistency = CleanExitBeaconConsistency::kMissingMissing;
} else {
consistency = platform_specific_beacon_value.value()
? CleanExitBeaconConsistency::kMissingClean
: CleanExitBeaconConsistency::kMissingDirty;
}
} else if (!platform_specific_beacon_value) {
consistency = beacon_file_beacon_value.value()
? CleanExitBeaconConsistency::kCleanMissing
: CleanExitBeaconConsistency::kDirtyMissing;
} else if (beacon_file_beacon_value.value()) {
consistency = platform_specific_beacon_value.value()
? CleanExitBeaconConsistency::kCleanClean
: CleanExitBeaconConsistency::kCleanDirty;
} else {
consistency = platform_specific_beacon_value.value()
? CleanExitBeaconConsistency::kDirtyClean
: CleanExitBeaconConsistency::kDirtyDirty;
}
base::UmaHistogramEnumeration("UMA.CleanExitBeaconConsistency3", consistency);
}
#endif // BUILDFLAG(IS_WIN) || BUILDFLAG(IS_IOS)
// Increments kVariationsCrashStreak if |did_previous_session_exit_cleanly| is
// false. Also, emits the crash streak to a histogram.
//
// If |beacon_file_contents| are given, then the beacon file is used to retrieve
// the crash streak. Otherwise, |local_state| is used.
void MaybeIncrementCrashStreak(bool did_previous_session_exit_cleanly,
base::Value* beacon_file_contents,
PrefService* local_state) {
int num_crashes;
if (beacon_file_contents) {
absl::optional<int> crash_streak =
beacon_file_contents->GetDict().FindInt(kVariationsCrashStreak);
// Any contents without the key should have been rejected by
// MaybeGetFileContents().
DCHECK(crash_streak);
num_crashes = crash_streak.value();
} else {
// TODO(crbug/1341087): Consider not falling back to Local State for clients
// on platforms that support the beacon file.
num_crashes = local_state->GetInteger(kVariationsCrashStreak);
}
if (!did_previous_session_exit_cleanly) {
// Increment the crash streak if the previous session crashed. Note that the
// streak is not cleared if the previous run didnt crash. Instead, its
// incremented on each crash until Chrome is able to successfully fetch a
// new seed. This way, a seed update that mostly destabilizes Chrome still
// results in a fallback to Variations Safe Mode.
//
// The crash streak is incremented here rather than in a variations-related
// class for two reasons. First, the crash streak depends on whether Chrome
// exited cleanly in the last session, which is first checked via
// CleanExitBeacon::Initialize(). Second, if the crash streak were updated
// in another function, any crash between beacon initialization and the
// other function might cause the crash streak to not be to incremented.
// "Might" because the updated crash streak also needs to be persisted to
// disk. A consequence of failing to increment the crash streak is that
// Chrome might undercount or be completely unaware of repeated crashes
// early on in startup.
++num_crashes;
// For platforms that use the beacon file, the crash streak is written
// synchronously to disk later on in startup via
// MaybeExtendVariationsSafeMode() and WriteBeaconFile(). The crash streak
// is intentionally not written to the beacon file here. If the beacon file
// indicates that Chrome failed to exit cleanly, then Chrome got at
// least as far as MaybeExtendVariationsSafeMode(), which is during the
// PostEarlyInitialization stage when native code is being synchronously
// executed. Chrome should also be able to reach that point in this session.
//
// For platforms that do not use the beacon file, the crash streak is
// scheduled to be written to disk later on in startup. At the latest, this
// is done when a Local State write is scheduled via WriteBeaconFile(). A
// write is not scheduled here for three reasons.
//
// 1. It is an expensive operation.
// 2. Android WebLayer (one of the two platforms that does not use the
// beacon file) did not appear to benefit from scheduling the write. See
// crbug/1341850 for details.
// 3. Android WebView (the other beacon-file-less platform) has its own
// Variations Safe Mode mechanism and does not need the crash streak.
local_state->SetInteger(kVariationsCrashStreak, num_crashes);
}
base::UmaHistogramSparse("Variations.SafeMode.Streak.Crashes",
std::clamp(num_crashes, 0, 100));
}
// Records |file_state| in a histogram.
void RecordBeaconFileState(BeaconFileState file_state) {
base::UmaHistogramEnumeration(
"Variations.ExtendedSafeMode.BeaconFileStateAtStartup", file_state);
}
// Returns the contents of the file at |beacon_file_path| if the following
// conditions are all true. Otherwise, returns nullptr.
//
// 1. The file path is non-empty.
// 2. The file exists.
// 3. The file is successfully read.
// 4. The file contents are in the expected format with the expected info.
//
// The file may not exist for the below reasons:
//
// 1. The file is unsupported on the platform.
// 2. This is the first session after a client updates to or installs a Chrome
// version that uses the beacon file. The beacon file launched on desktop
// and iOS in M102 and on Android Chrome in M103.
// 3. Android Chrome clients with only background sessions may never write a
// beacon file.
// 4. A user may delete the file.
std::unique_ptr<base::Value> MaybeGetFileContents(
const base::FilePath& beacon_file_path) {
if (beacon_file_path.empty())
return nullptr;
int error_code;
JSONFileValueDeserializer deserializer(beacon_file_path);
std::unique_ptr<base::Value> beacon_file_contents =
deserializer.Deserialize(&error_code, /*error_message=*/nullptr);
if (!beacon_file_contents) {
RecordBeaconFileState(BeaconFileState::kNotDeserializable);
base::UmaHistogramSparse(
"Variations.ExtendedSafeMode.BeaconFileDeserializationError",
error_code);
return nullptr;
}
if (!beacon_file_contents->is_dict() ||
beacon_file_contents->GetDict().empty()) {
RecordBeaconFileState(BeaconFileState::kMissingDictionary);
return nullptr;
}
const base::Value::Dict& beacon_dict = beacon_file_contents->GetDict();
if (!beacon_dict.FindInt(kVariationsCrashStreak)) {
RecordBeaconFileState(BeaconFileState::kMissingCrashStreak);
return nullptr;
}
if (!beacon_dict.FindBool(prefs::kStabilityExitedCleanly)) {
RecordBeaconFileState(BeaconFileState::kMissingBeacon);
return nullptr;
}
RecordBeaconFileState(BeaconFileState::kReadable);
return beacon_file_contents;
}
} // namespace
const base::FilePath::CharType kCleanExitBeaconFilename[] =
FILE_PATH_LITERAL("Variations");
CleanExitBeacon::CleanExitBeacon(const std::wstring& backup_registry_key,
const base::FilePath& user_data_dir,
PrefService* local_state)
: backup_registry_key_(backup_registry_key),
user_data_dir_(user_data_dir),
local_state_(local_state),
initial_browser_last_live_timestamp_(
local_state->GetTime(prefs::kStabilityBrowserLastLiveTimeStamp)) {
DCHECK_NE(PrefService::INITIALIZATION_STATUS_WAITING,
local_state_->GetInitializationStatus());
}
void CleanExitBeacon::Initialize() {
DCHECK(!initialized_);
if (!user_data_dir_.empty()) {
// Platforms that pass an empty path do so deliberately. They should not
// use the beacon file.
beacon_file_path_ = user_data_dir_.Append(kCleanExitBeaconFilename);
}
std::unique_ptr<base::Value> beacon_file_contents =
MaybeGetFileContents(beacon_file_path_);
did_previous_session_exit_cleanly_ =
DidPreviousSessionExitCleanly(beacon_file_contents.get());
MaybeIncrementCrashStreak(did_previous_session_exit_cleanly_,
beacon_file_contents.get(), local_state_);
initialized_ = true;
}
bool CleanExitBeacon::DidPreviousSessionExitCleanly(
base::Value* beacon_file_contents) {
if (!IsBeaconFileSupported())
return local_state_->GetBoolean(prefs::kStabilityExitedCleanly);
absl::optional<bool> beacon_file_beacon_value =
beacon_file_contents ? beacon_file_contents->GetDict().FindBool(
prefs::kStabilityExitedCleanly)
: absl::nullopt;
#if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_IOS)
absl::optional<bool> backup_beacon_value = ExitedCleanly();
RecordBeaconConsistency(beacon_file_beacon_value, backup_beacon_value);
#endif // BUILDFLAG(IS_WIN) || BUILDFLAG(IS_IOS)
#if BUILDFLAG(IS_IOS)
// TODO(crbug/1231106): For the time being, this is a no-op; i.e.,
// ShouldUseUserDefaultsBeacon() always returns false.
if (ShouldUseUserDefaultsBeacon())
return backup_beacon_value.value_or(true);
#endif // BUILDFLAG(IS_IOS)
return beacon_file_beacon_value.value_or(true);
}
bool CleanExitBeacon::IsExtendedSafeModeSupported() const {
// All platforms that support the beacon file mechanism also happen to support
// Extended Variations Safe Mode.
return IsBeaconFileSupported();
}
void CleanExitBeacon::WriteBeaconValue(bool exited_cleanly,
bool is_extended_safe_mode) {
DCHECK(initialized_);
if (g_skip_clean_shutdown_steps)
return;
UpdateLastLiveTimestamp();
if (has_exited_cleanly_ && has_exited_cleanly_.value() == exited_cleanly) {
// It is possible to call WriteBeaconValue() with the same value for
// |exited_cleanly| twice during startup and shutdown on some platforms. If
// the current beacon value matches |exited_cleanly|, then return here to
// skip redundantly updating Local State, writing a beacon file, and on
// Windows and iOS, writing to platform-specific locations.
return;
}
if (is_extended_safe_mode) {
// |is_extended_safe_mode| can be true for only some platforms.
DCHECK(IsExtendedSafeModeSupported());
// |has_exited_cleanly_| should always be unset before starting to watch for
// browser crashes.
DCHECK(!has_exited_cleanly_);
// When starting to watch for browser crashes in the code covered by
// Extended Variations Safe Mode, the only valid value for |exited_cleanly|
// is `false`. `true` signals that Chrome should stop watching for crashes.
DCHECK(!exited_cleanly);
WriteBeaconFile(exited_cleanly);
} else {
// TODO(crbug/1341864): Stop updating |kStabilityExitedCleanly| on platforms
// that support the beacon file.
local_state_->SetBoolean(prefs::kStabilityExitedCleanly, exited_cleanly);
if (IsBeaconFileSupported()) {
WriteBeaconFile(exited_cleanly);
} else {
// Schedule a Local State write on platforms that back the beacon value
// using Local State rather than the beacon file.
local_state_->CommitPendingWrite();
}
}
#if BUILDFLAG(IS_WIN)
base::win::RegKey regkey;
if (regkey.Create(HKEY_CURRENT_USER, backup_registry_key_.c_str(),
KEY_ALL_ACCESS) == ERROR_SUCCESS) {
regkey.WriteValue(base::ASCIIToWide(prefs::kStabilityExitedCleanly).c_str(),
exited_cleanly ? 1u : 0u);
}
#elif BUILDFLAG(IS_IOS)
SetUserDefaultsBeacon(exited_cleanly);
#endif // BUILDFLAG(IS_WIN)
has_exited_cleanly_ = absl::make_optional(exited_cleanly);
}
#if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_IOS)
absl::optional<bool> CleanExitBeacon::ExitedCleanly() {
#if BUILDFLAG(IS_WIN)
base::win::RegKey regkey;
DWORD value = 0u;
if (regkey.Open(HKEY_CURRENT_USER, backup_registry_key_.c_str(),
KEY_ALL_ACCESS) == ERROR_SUCCESS &&
regkey.ReadValueDW(
base::ASCIIToWide(prefs::kStabilityExitedCleanly).c_str(), &value) ==
ERROR_SUCCESS) {
return value ? true : false;
}
return absl::nullopt;
#endif // BUILDFLAG(IS_WIN)
#if BUILDFLAG(IS_IOS)
if (HasUserDefaultsBeacon())
return GetUserDefaultsBeacon();
return absl::nullopt;
#endif // BUILDFLAG(IS_IOS)
}
#endif // BUILDFLAG(IS_WIN) || BUILDFLAG(IS_IOS)
void CleanExitBeacon::UpdateLastLiveTimestamp() {
local_state_->SetTime(prefs::kStabilityBrowserLastLiveTimeStamp,
base::Time::Now());
}
const base::FilePath CleanExitBeacon::GetUserDataDirForTesting() const {
return user_data_dir_;
}
base::FilePath CleanExitBeacon::GetBeaconFilePathForTesting() const {
return beacon_file_path_;
}
// static
void CleanExitBeacon::RegisterPrefs(PrefRegistrySimple* registry) {
registry->RegisterBooleanPref(prefs::kStabilityExitedCleanly, true);
registry->RegisterTimePref(prefs::kStabilityBrowserLastLiveTimeStamp,
base::Time(), PrefRegistry::LOSSY_PREF);
// This Variations-Safe-Mode-related pref is registered here rather than in
// SafeSeedManager::RegisterPrefs() because the CleanExitBeacon is
// responsible for incrementing this value. (See the comments in
// MaybeIncrementCrashStreak() for more details.)
registry->RegisterIntegerPref(kVariationsCrashStreak, 0);
}
// static
void CleanExitBeacon::EnsureCleanShutdown(PrefService* local_state) {
if (!g_skip_clean_shutdown_steps)
CHECK(local_state->GetBoolean(prefs::kStabilityExitedCleanly));
}
// static
void CleanExitBeacon::SetStabilityExitedCleanlyForTesting(
PrefService* local_state,
bool exited_cleanly) {
local_state->SetBoolean(prefs::kStabilityExitedCleanly, exited_cleanly);
#if BUILDFLAG(IS_IOS)
SetUserDefaultsBeacon(exited_cleanly);
#endif // BUILDFLAG(IS_IOS)
}
// static
std::string CleanExitBeacon::CreateBeaconFileContentsForTesting(
bool exited_cleanly,
int crash_streak) {
const std::string exited_cleanly_str = exited_cleanly ? "true" : "false";
return base::StringPrintf(
"{\n"
" \"user_experience_metrics.stability.exited_cleanly\":%s,\n"
" \"variations_crash_streak\":%s\n"
"}",
exited_cleanly_str.data(), base::NumberToString(crash_streak).data());
}
// static
void CleanExitBeacon::ResetStabilityExitedCleanlyForTesting(
PrefService* local_state) {
local_state->ClearPref(prefs::kStabilityExitedCleanly);
#if BUILDFLAG(IS_IOS)
ResetUserDefaultsBeacon();
#endif // BUILDFLAG(IS_IOS)
}
// static
void CleanExitBeacon::SkipCleanShutdownStepsForTesting() {
g_skip_clean_shutdown_steps = true;
}
bool CleanExitBeacon::IsBeaconFileSupported() const {
return !beacon_file_path_.empty();
}
void CleanExitBeacon::WriteBeaconFile(bool exited_cleanly) const {
base::Value::Dict dict;
dict.Set(prefs::kStabilityExitedCleanly, exited_cleanly);
dict.Set(kVariationsCrashStreak,
local_state_->GetInteger(kVariationsCrashStreak));
std::string json_string;
JSONStringValueSerializer serializer(&json_string);
bool success = serializer.Serialize(dict);
DCHECK(success);
DCHECK(!json_string.empty());
{
base::ScopedAllowBlocking allow_io;
success = base::WriteFile(beacon_file_path_, json_string);
}
base::UmaHistogramBoolean("Variations.ExtendedSafeMode.BeaconFileWrite",
success);
}
} // namespace metrics