From b202cc1b8eecfe973e75eb5db36e6b381fbca63b Mon Sep 17 00:00:00 2001
From: Alejandro Revilla <apr@jpos.org>
Date: Tue, 28 Nov 2023 13:05:42 -0300
Subject: [PATCH] Protect against NTP sending clock backward.

---
 jpos/src/main/java/org/jpos/transaction/Context.java | 3 ++-
 jpos/src/main/java/org/jpos/util/BlockingQueue.java  | 3 ++-
 jpos/src/main/java/org/jpos/util/DirPoll.java        | 7 ++++---
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/jpos/src/main/java/org/jpos/transaction/Context.java b/jpos/src/main/java/org/jpos/transaction/Context.java
index 82ecccf92c..fc2953fd61 100644
--- a/jpos/src/main/java/org/jpos/transaction/Context.java
+++ b/jpos/src/main/java/org/jpos/transaction/Context.java
@@ -195,7 +195,8 @@ public synchronized <T> T get (Object key, long timeout) {
                 (now = System.currentTimeMillis()) < end)
         {
             try {
-                this.wait (end - now);
+                if (end > now)
+                    this.wait (end - now);
             } catch (InterruptedException ignored) { }
         }
         return obj;
diff --git a/jpos/src/main/java/org/jpos/util/BlockingQueue.java b/jpos/src/main/java/org/jpos/util/BlockingQueue.java
index 36ba37024c..9cd861d88c 100644
--- a/jpos/src/main/java/org/jpos/util/BlockingQueue.java
+++ b/jpos/src/main/java/org/jpos/util/BlockingQueue.java
@@ -79,7 +79,8 @@ public synchronized Object dequeue (long timeout)
         long maxTime = System.currentTimeMillis() + timeout;
         try {
             while (queue.size() == 0 && System.currentTimeMillis() < maxTime) {
-                wait (timeout);
+                if (timeout > 0L)
+                    wait (timeout);
                 if (closed)
                     throw new Closed();
             }
diff --git a/jpos/src/main/java/org/jpos/util/DirPoll.java b/jpos/src/main/java/org/jpos/util/DirPoll.java
index 955abba88b..43e921e428 100644
--- a/jpos/src/main/java/org/jpos/util/DirPoll.java
+++ b/jpos/src/main/java/org/jpos/util/DirPoll.java
@@ -279,7 +279,7 @@ public void run() {
                 }
                 else {
                     synchronized (shutdownMonitor) {
-                        if (!shutdown) {
+                        if (!shutdown && pollInterval > 0L) {
                             shutdownMonitor.wait(pollInterval);
                         }
                     }
@@ -289,7 +289,7 @@ public void run() {
                 Logger.log (new LogEvent (this, "dirpoll", e));
                 try {
                     synchronized (shutdownMonitor) {
-                        if (!shutdown) {
+                        if (!shutdown && pollInterval > 0L) {
                             shutdownMonitor.wait(pollInterval * 10);
                         }
                     }
@@ -458,7 +458,8 @@ else if (processor instanceof Processor) {
                         synchronized (shutdownMonitor) {
                             if (!shutdown) {
                                 try {
-                                    shutdownMonitor.wait(pollInterval * 10); // retry delay (pollInterval defaults to 100ms)
+                                    if (pollInterval > 0L)
+                                        shutdownMonitor.wait(pollInterval * 10); // retry delay (pollInterval defaults to 100ms)
                                 } catch (InterruptedException ie) {
                                 }
                             }