Simplify crash conditions in NetworkStackClient

import android.net.ip.IIpClientCallbacks;

import android.net.util.SharedLog;

import android.os.Binder;

import android.os.Build;

import android.os.Environment;

import android.os.IBinder;

import android.os.Process;

import android.os.SystemClock;

import android.os.UserHandle;

import android.provider.DeviceConfig;

import android.text.format.DateUtils;

import android.util.ArraySet;

import android.util.Slog;

    private static final int NETWORKSTACK_TIMEOUT_MS = 10_000;

    private static final String IN_PROCESS_SUFFIX = ".InProcess";

    private static final String PREFS_FILE = "NetworkStackClientPrefs.xml";

    private static final String PREF_KEY_LAST_CRASH_UPTIME = "lastcrash";

    private static final String PREF_KEY_LAST_CRASH_TIME = "lastcrash_time";

    private static final String CONFIG_MIN_CRASH_INTERVAL_MS = "min_crash_interval";

    private static final String CONFIG_MIN_UPTIME_BEFORE_CRASH_MS = "min_uptime_before_crash";

    private static final String CONFIG_ALWAYS_RATELIMIT_NETWORKSTACK_CRASH =

            "always_ratelimit_networkstack_crash";

    // Even if the network stack is lost, do not crash the system more often than this.

    // Connectivity would be broken, but if the user needs the device for something urgent

    // (like calling emergency services) we should not bootloop the device.

    // This is the default value: the actual value can be adjusted via device config.

    private static final long DEFAULT_MIN_CRASH_INTERVAL_MS = 6 * 3_600_000L;

    private static final long DEFAULT_MIN_CRASH_INTERVAL_MS = 6 * DateUtils.HOUR_IN_MILLIS;

    // Even if the network stack is lost, do not crash the system server if it was less than

    // this much after boot. This avoids bootlooping the device, and crashes should address very

    // infrequent failures, not failures on boot.

    private static final long DEFAULT_MIN_UPTIME_BEFORE_CRASH_MS = 30 * DateUtils.MINUTE_IN_MILLIS;

    private static NetworkStackClient sInstance;

    private volatile boolean mWasSystemServerInitialized = false;

    /**

     * If non-zero, indicates that the last framework start happened after a crash of the

     * NetworkStack which was at the specified uptime.

     */

    private volatile long mLastCrashUptime = 0L;

    @GuardedBy("mHealthListeners")

    private final ArraySet<NetworkStackHealthListener> mHealthListeners = new ArraySet<>();

    public void start(Context context) {

        log("Starting network stack");

        final SharedPreferences prefs = getSharedPreferences(context);

        mLastCrashUptime = prefs.getLong(PREF_KEY_LAST_CRASH_UPTIME, 0L);

        // Remove the preference after getting the last crash uptime, so mLastCrashUptime always

        // indicates this is the first start since the last crash.

        prefs.edit().remove(PREF_KEY_LAST_CRASH_UPTIME).commit();

        final PackageManager pm = context.getPackageManager();

        // Try to bind in-process if the device was shipped with an in-process version

        logWtf(message, null);

        // uptime is monotonic even after a framework restart

        final long uptime = SystemClock.elapsedRealtime();

        final long now = System.currentTimeMillis();

        final long minCrashIntervalMs = DeviceConfig.getLong(DeviceConfig.NAMESPACE_CONNECTIVITY,

                CONFIG_MIN_CRASH_INTERVAL_MS, DEFAULT_MIN_CRASH_INTERVAL_MS);

        final long minUptimeBeforeCrash = DeviceConfig.getLong(DeviceConfig.NAMESPACE_CONNECTIVITY,

                CONFIG_MIN_UPTIME_BEFORE_CRASH_MS, DEFAULT_MIN_UPTIME_BEFORE_CRASH_MS);

        final boolean alwaysRatelimit = DeviceConfig.getBoolean(DeviceConfig.NAMESPACE_CONNECTIVITY,

                CONFIG_ALWAYS_RATELIMIT_NETWORKSTACK_CRASH, false);

        // Either the framework was not restarted after a crash of the NetworkStack, or the min

        // crash interval has passed since then.

        if (mLastCrashUptime == 0L || uptime - mLastCrashUptime > minCrashIntervalMs) {

        final SharedPreferences prefs = getSharedPreferences(context);

        final long lastCrashTime = tryGetLastCrashTime(prefs);

        // Only crash if there was enough time since boot, and (if known) enough time passed since

        // the last crash.

        // time and lastCrashTime may be unreliable if devices have incorrect clock time, but they

        // are only used to limit the number of crashes compared to only using the time since boot,

        // which would also be OK behavior by itself.

        // - If lastCrashTime is incorrectly more than the current time, only look at uptime

        // - If it is much less than current time, only look at uptime

        // - If current time is during the next few hours after last crash time, don't crash.

        //   Considering that this only matters if last boot was some time ago, it's likely that

        //   time will be set correctly. Otherwise, not crashing is not a big problem anyway. Being

        //   in this last state would also not last for long since the window is only a few hours.

        final boolean alwaysCrash = Build.IS_DEBUGGABLE && !alwaysRatelimit;

        final boolean justBooted = uptime < minUptimeBeforeCrash;

        final boolean haveLastCrashTime = (lastCrashTime != 0) && (lastCrashTime < now);

        final boolean haveKnownRecentCrash =

                haveLastCrashTime && (now < lastCrashTime + minCrashIntervalMs);

        if (alwaysCrash || (!justBooted && !haveKnownRecentCrash)) {

            // The system is not bound to its network stack (for example due to a crash in the

            // network stack process): better crash rather than stay in a bad state where all

            // networking is broken.

            // Using device-encrypted SharedPreferences as DeviceConfig does not have a synchronous

            // API to persist settings before a crash.

            final SharedPreferences prefs = getSharedPreferences(context);

            if (!prefs.edit().putLong(PREF_KEY_LAST_CRASH_UPTIME, uptime).commit()) {

                logWtf("Could not persist last crash uptime", null);

            }

            tryWriteLastCrashTime(prefs, now);

            throw new IllegalStateException(message);

        }

        }

    }

    private SharedPreferences getSharedPreferences(Context context) {

    @Nullable

    private SharedPreferences getSharedPreferences(@NonNull Context context) {

        try {

            final File prefsFile = new File(

                    Environment.getDataSystemDeDirectory(UserHandle.USER_SYSTEM), PREFS_FILE);

            return context.createDeviceProtectedStorageContext()

                    .getSharedPreferences(prefsFile, Context.MODE_PRIVATE);

        } catch (Throwable e) {

            logWtf("Error loading shared preferences", e);

            return null;

        }

    }

    private long tryGetLastCrashTime(@Nullable SharedPreferences prefs) {

        if (prefs == null) return 0L;

        try {

            return prefs.getLong(PREF_KEY_LAST_CRASH_TIME, 0L);

        } catch (Throwable e) {

            logWtf("Error getting last crash time", e);

            return 0L;

        }

    }

    private void tryWriteLastCrashTime(@Nullable SharedPreferences prefs, long value) {

        if (prefs == null) return;

        try {

            prefs.edit().putLong(PREF_KEY_LAST_CRASH_TIME, value).commit();

        } catch (Throwable e) {

            logWtf("Error writing last crash time", e);

        }

    }

    /**