From 11a2ed074318ffe20735ef3a1e9cf4ece5bd3879 Mon Sep 17 00:00:00 2001
From: Greyson Parrelli <greyson@signal.org>
Date: Wed, 10 Apr 2019 12:53:55 -0400
Subject: [PATCH] Increase reliability of locally logging crashes.

Exception logging tends to be race-y, so now we block and wait
for all logs to be written before continuing with the crash.
---
 .../securesms/ApplicationContext.java            |  2 +-
 .../securesms/logging/AndroidLogger.java         |  4 ++++
 src/org/thoughtcrime/securesms/logging/Log.java  |  9 +++++++++
 .../securesms/logging/PersistentLogger.java      | 16 +++++++++++++++-
 .../logging/UncaughtExceptionLogger.java         |  7 +++----
 5 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/src/org/thoughtcrime/securesms/ApplicationContext.java b/src/org/thoughtcrime/securesms/ApplicationContext.java
index d75df36da1..b8b0b0cf80 100644
--- a/src/org/thoughtcrime/securesms/ApplicationContext.java
+++ b/src/org/thoughtcrime/securesms/ApplicationContext.java
@@ -185,7 +185,7 @@ public class ApplicationContext extends MultiDexApplication implements Dependenc
 
   private void initializeCrashHandling() {
     final Thread.UncaughtExceptionHandler originalHandler = Thread.getDefaultUncaughtExceptionHandler();
-    Thread.setDefaultUncaughtExceptionHandler(new UncaughtExceptionLogger(originalHandler, persistentLogger));
+    Thread.setDefaultUncaughtExceptionHandler(new UncaughtExceptionLogger(originalHandler));
   }
 
   private void initializeJobManager() {
diff --git a/src/org/thoughtcrime/securesms/logging/AndroidLogger.java b/src/org/thoughtcrime/securesms/logging/AndroidLogger.java
index e7695a0b65..570fda623a 100644
--- a/src/org/thoughtcrime/securesms/logging/AndroidLogger.java
+++ b/src/org/thoughtcrime/securesms/logging/AndroidLogger.java
@@ -31,4 +31,8 @@ public class AndroidLogger extends Log.Logger {
   public void wtf(String tag, String message, Throwable t) {
     android.util.Log.wtf(tag, message, t);
   }
+
+  @Override
+  public void blockUntilAllWritesFinished() {
+  }
 }
diff --git a/src/org/thoughtcrime/securesms/logging/Log.java b/src/org/thoughtcrime/securesms/logging/Log.java
index 9ec2b11aea..31dc299227 100644
--- a/src/org/thoughtcrime/securesms/logging/Log.java
+++ b/src/org/thoughtcrime/securesms/logging/Log.java
@@ -127,6 +127,14 @@ public class Log {
     return simpleName;
   }
 
+  public static void blockUntilAllWritesFinished() {
+    if (loggers != null) {
+      for (Logger logger : loggers) {
+        logger.blockUntilAllWritesFinished();
+      }
+    }
+  }
+
   public static abstract class Logger {
     public abstract void v(String tag, String message, Throwable t);
     public abstract void d(String tag, String message, Throwable t);
@@ -134,5 +142,6 @@ public class Log {
     public abstract void w(String tag, String message, Throwable t);
     public abstract void e(String tag, String message, Throwable t);
     public abstract void wtf(String tag, String message, Throwable t);
+    public abstract void blockUntilAllWritesFinished();
   }
 }
diff --git a/src/org/thoughtcrime/securesms/logging/PersistentLogger.java b/src/org/thoughtcrime/securesms/logging/PersistentLogger.java
index 2720557f2e..334df55762 100644
--- a/src/org/thoughtcrime/securesms/logging/PersistentLogger.java
+++ b/src/org/thoughtcrime/securesms/logging/PersistentLogger.java
@@ -17,6 +17,7 @@ import java.util.Arrays;
 import java.util.Date;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
 
@@ -47,7 +48,7 @@ public class PersistentLogger extends Log.Logger {
     this.context  = context.getApplicationContext();
     this.secret   = LogSecretProvider.getOrCreateAttachmentSecret(context);
     this.executor = Executors.newSingleThreadExecutor(r -> {
-      Thread thread = new Thread(r, "logger");
+      Thread thread = new Thread(r, "PersistentLogger");
       thread.setPriority(Thread.MIN_PRIORITY);
       return thread;
     });
@@ -85,6 +86,19 @@ public class PersistentLogger extends Log.Logger {
     write(LOG_WTF, tag, message, t);
   }
 
+  @Override
+  public void blockUntilAllWritesFinished() {
+    CountDownLatch latch = new CountDownLatch(1);
+
+    executor.execute(latch::countDown);
+
+    try {
+      latch.await();
+    } catch (InterruptedException e) {
+      android.util.Log.w(TAG, "Failed to wait for all writes.");
+    }
+  }
+
   @WorkerThread
   public ListenableFuture<String> getLogs() {
     final SettableFuture<String> future = new SettableFuture<>();
diff --git a/src/org/thoughtcrime/securesms/logging/UncaughtExceptionLogger.java b/src/org/thoughtcrime/securesms/logging/UncaughtExceptionLogger.java
index a3da1aeac9..642703695a 100644
--- a/src/org/thoughtcrime/securesms/logging/UncaughtExceptionLogger.java
+++ b/src/org/thoughtcrime/securesms/logging/UncaughtExceptionLogger.java
@@ -7,16 +7,15 @@ public class UncaughtExceptionLogger implements Thread.UncaughtExceptionHandler
   private static final String TAG = UncaughtExceptionLogger.class.getSimpleName();
 
   private final Thread.UncaughtExceptionHandler originalHandler;
-  private final PersistentLogger                persistentLogger;
 
-  public UncaughtExceptionLogger(@NonNull Thread.UncaughtExceptionHandler originalHandler, @NonNull PersistentLogger persistentLogger) {
-    this.originalHandler  = originalHandler;
-    this.persistentLogger = persistentLogger;
+  public UncaughtExceptionLogger(@NonNull Thread.UncaughtExceptionHandler originalHandler) {
+    this.originalHandler = originalHandler;
   }
 
   @Override
   public void uncaughtException(Thread t, Throwable e) {
     Log.e(TAG, "", e);
+    Log.blockUntilAllWritesFinished();
     originalHandler.uncaughtException(t, e);
   }
 }