From 1603204ba5392d375e05ecf2c5b2fea7309f4cf1 Mon Sep 17 00:00:00 2001
From: Christopher Tate <ctate@google.com>
Date: Fri, 5 Oct 2018 15:53:50 -0700
Subject: [PATCH] Fix persisted job handling in bad-boot-RTC situations

Persisted jobs were inadvertently being discarded rather than
rescheduled with appropriate time constraints.  The underlying
bug is that the cancel-with-replacement code path was failing
to manage the replacement properly, and the other code path
leading to it was working around the bug by explicitly
rescheduling the job following cancellation.

Test: atest CtsJobSchedulerTestCases
Bug: 114292041
Bug: 117346686
Change-Id: I3a77e8a38c2f7028b61791bafd9c88b7a714ff6d
---
 .../server/job/JobSchedulerService.java       | 22 +++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/services/core/java/com/android/server/job/JobSchedulerService.java b/services/core/java/com/android/server/job/JobSchedulerService.java
index 389782a91d065..dd993b842aca9 100644
--- a/services/core/java/com/android/server/job/JobSchedulerService.java
+++ b/services/core/java/com/android/server/job/JobSchedulerService.java
@@ -877,14 +877,17 @@ public class JobSchedulerService extends com.android.server.SystemService
             // This may throw a SecurityException.
             jobStatus.prepareLocked(ActivityManager.getService());
 
-            if (toCancel != null) {
-                cancelJobImplLocked(toCancel, jobStatus, "job rescheduled by app");
-            }
             if (work != null) {
                 // If work has been supplied, enqueue it into the new job.
                 jobStatus.enqueueWorkLocked(ActivityManager.getService(), work);
             }
-            startTrackingJobLocked(jobStatus, toCancel);
+
+            if (toCancel != null) {
+                // Implicitly replaces the existing job record with the new instance
+                cancelJobImplLocked(toCancel, jobStatus, "job rescheduled by app");
+            } else {
+                startTrackingJobLocked(jobStatus, null);
+            }
             StatsLog.write_non_chained(StatsLog.SCHEDULED_JOB_STATE_CHANGED,
                     uId, null, jobStatus.getBatteryName(),
                     StatsLog.SCHEDULED_JOB_STATE_CHANGED__STATE__SCHEDULED,
@@ -1013,6 +1016,12 @@ public class JobSchedulerService extends com.android.server.SystemService
         }
     }
 
+    /**
+     * Cancel the given job, stopping it if it's currently executing.  If {@code incomingJob}
+     * is null, the cancelled job is removed outright from the system.  If
+     * {@code incomingJob} is non-null, it replaces {@code cancelled} in the store of
+     * currently scheduled jobs.
+     */
     private void cancelJobImplLocked(JobStatus cancelled, JobStatus incomingJob, String reason) {
         if (DEBUG) Slog.d(TAG, "CANCEL: " + cancelled.toShortString());
         cancelled.unprepareLocked(ActivityManager.getService());
@@ -1023,6 +1032,11 @@ public class JobSchedulerService extends com.android.server.SystemService
         }
         // Cancel if running.
         stopJobOnServiceContextLocked(cancelled, JobParameters.REASON_CANCELED, reason);
+        // If this is a replacement, bring in the new version of the job
+        if (incomingJob != null) {
+            if (DEBUG) Slog.i(TAG, "Tracking replacement job " + incomingJob.toShortString());
+            startTrackingJobLocked(incomingJob, cancelled);
+        }
         reportActiveLocked();
     }