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Merge "Prevent some alarm pathologies" into lmp-mr1-dev

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Christopher Tate
2014-11-18 23:49:52 +00:00
committed by Android (Google) Code Review
parent 735f22850e 498c6cbd78
commit 04eb368d03
1 changed files with 20 additions and 1 deletions
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21
services/core/java/com/android/server/AlarmManagerService.java
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@@ -75,6 +75,12 @@ class AlarmManagerService extends SystemService {
// warning message. The time duration is in milliseconds.
private static final long LATE_ALARM_THRESHOLD = 10 * 1000;
// Minimum futurity of a new alarm
private static final long MIN_FUTURITY = 5 * 1000; // 5 seconds, in millis
// Minimum alarm recurrence interval
private static final long MIN_INTERVAL = 60 * 1000; // one minute, in millis
private static final int RTC_WAKEUP_MASK = 1 << RTC_WAKEUP;
private static final int RTC_MASK = 1 << RTC;
private static final int ELAPSED_REALTIME_WAKEUP_MASK = 1 << ELAPSED_REALTIME_WAKEUP;
@@ -696,6 +702,15 @@ class AlarmManagerService extends SystemService {
windowLength = AlarmManager.INTERVAL_HOUR;
}
// Sanity check the recurrence interval. This will catch people who supply
// seconds when the API expects milliseconds.
if (interval > 0 && interval < MIN_INTERVAL) {
Slog.w(TAG, "Suspiciously short interval " + interval
+ " millis; expanding to " + (int)(MIN_INTERVAL/1000)
+ " seconds");
interval = MIN_INTERVAL;
}
if (type < RTC_WAKEUP || type > ELAPSED_REALTIME) {
throw new IllegalArgumentException("Invalid alarm type " + type);
}
@@ -709,7 +724,11 @@ class AlarmManagerService extends SystemService {
}
final long nowElapsed = SystemClock.elapsedRealtime();
final long triggerElapsed = convertToElapsed(triggerAtTime, type);
final long nominalTrigger = convertToElapsed(triggerAtTime, type);
// Try to prevent spamming by making sure we aren't firing alarms in the immediate future
final long minTrigger = nowElapsed + MIN_FUTURITY;
final long triggerElapsed = (nominalTrigger > minTrigger) ? nominalTrigger : minTrigger;
final long maxElapsed;
if (windowLength == AlarmManager.WINDOW_EXACT) {
maxElapsed = triggerElapsed;