From f0f1d83624a8aafe402d00e14a83078b2f2c2471 Mon Sep 17 00:00:00 2001
From: Greg Kaiser <gkaiser@google.com>
Date: Mon, 23 Mar 2020 09:03:39 -0700
Subject: [PATCH] ShellSubscriber: Avoid rollover bug

We initialize 'mToken' instead of leaving it uninitialized, making
it much less likely to rollover.  In additional, we change our
check to inequality, to handle rollover if that were to happen.

There is the (theoretical) possibility of exactly 2^32 other
requests being claimed between our claim and our check.  It's
assumed that is essentially impossible and not a concern.

Test: TreeHugger
Bug: 150619687
Change-Id: Iee303e05082a6b3b31ed546bd62d3afe67c771d8
---
 cmds/statsd/src/shell/ShellSubscriber.cpp | 2 +-
 cmds/statsd/src/shell/ShellSubscriber.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/cmds/statsd/src/shell/ShellSubscriber.cpp b/cmds/statsd/src/shell/ShellSubscriber.cpp
index 6fa165475029c..c677222f31eb4 100644
--- a/cmds/statsd/src/shell/ShellSubscriber.cpp
+++ b/cmds/statsd/src/shell/ShellSubscriber.cpp
@@ -41,7 +41,7 @@ void ShellSubscriber::startNewSubscription(int in, int out, int timeoutSec) {
 
     // critical-section
     std::unique_lock<std::mutex> lock(mMutex);
-    if (myToken < mToken) {
+    if (myToken != mToken) {
         // Some other subscription has already come in. Stop.
         return;
     }
diff --git a/cmds/statsd/src/shell/ShellSubscriber.h b/cmds/statsd/src/shell/ShellSubscriber.h
index 7fd625e472b40..2f9b61a257a8b 100644
--- a/cmds/statsd/src/shell/ShellSubscriber.h
+++ b/cmds/statsd/src/shell/ShellSubscriber.h
@@ -108,7 +108,7 @@ private:
 
     std::shared_ptr<SubscriptionInfo> mSubscriptionInfo = nullptr;
 
-    int mToken;
+    int mToken = 0;
 };
 
 }  // namespace statsd