From eb56ba363758b58516c5043080af13bbdc598be1 Mon Sep 17 00:00:00 2001
From: computezrmle <57127745+computezrmle@users.noreply.github.com>
Date: Tue, 29 Oct 2024 16:28:56 +0100
Subject: [PATCH 1/2] Heartbeat checks deal with time leaps

---
 samples/vboxwrapper/vboxwrapper.cpp | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/samples/vboxwrapper/vboxwrapper.cpp b/samples/vboxwrapper/vboxwrapper.cpp
index 9f15ee68ae..51f250187f 100644
--- a/samples/vboxwrapper/vboxwrapper.cpp
+++ b/samples/vboxwrapper/vboxwrapper.cpp
@@ -428,6 +428,7 @@ int main(int argc, char** argv) {
     double timeout = 0.0;
     bool report_net_usage = false;
     bool initial_heartbeat_check = true;
+    int backtoback_heartbeat_failure = 1;
     double net_usage_timer = 600;
     int vm_image = 0;
     unsigned long vm_exit_code = 0;
@@ -1050,8 +1051,9 @@ int main(int argc, char** argv) {
             boinc_finish(EXIT_ABORTED_BY_CLIENT);
         }
         if (pVM->heartbeat_filename.size()) {
+            int backtoback = 3;
 
-            if (elapsed_time >= (last_heartbeat_elapsed_time + pVM->minimum_heartbeat_interval)) {
+            if (elapsed_time >= (last_heartbeat_elapsed_time + pVM->minimum_heartbeat_interval/backtoback)) {
 
                 int return_code = BOINC_SUCCESS;
                 bool should_exit = false;
@@ -1079,10 +1081,24 @@ int main(int argc, char** argv) {
                             // Heartbeat successful
                             last_heartbeat_mod_time = heartbeat_stat.st_mtime;
                             last_heartbeat_elapsed_time = elapsed_time;
+                            backtoback_heartbeat_failure = 1;
                         } else {
-                            vboxlog_msg("VM Heartbeat file specified, but missing heartbeat.");
-                            return_code = ERR_TIMEOUT;
-                            should_exit = true;
+                            // Timestamps are not always monotonuous
+                            // or in sync between guest and host
+                            // e.g. after a suspend/resume
+                            // or when local time switches between
+                            // normal time and DST
+                            //
+                            // Instead of fiddling around with complex checks
+                            // simply count backtoback inconsistencies
+                            //
+                            if (backtoback_heartbeat_failure < backtoback) {
+                                backtoback_heartbeat_failure++;
+                            } else {
+                                vboxlog_msg("VM Heartbeat file specified, but missing heartbeat.");
+                                return_code = ERR_TIMEOUT;
+                                should_exit = true;
+                            }
                         }
                     }
                 }

From d08ad6a980a0fc5d5cdb92de918be8faaaa3c4aa Mon Sep 17 00:00:00 2001
From: computezrmle <57127745+computezrmle@users.noreply.github.com>
Date: Tue, 29 Oct 2024 17:00:06 +0100
Subject: [PATCH 2/2] Update vboxwrapper.cpp

---
 samples/vboxwrapper/vboxwrapper.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/samples/vboxwrapper/vboxwrapper.cpp b/samples/vboxwrapper/vboxwrapper.cpp
index 51f250187f..f2392a2916 100644
--- a/samples/vboxwrapper/vboxwrapper.cpp
+++ b/samples/vboxwrapper/vboxwrapper.cpp
@@ -1079,8 +1079,6 @@ int main(int argc, char** argv) {
 
                         if (heartbeat_stat.st_mtime > last_heartbeat_mod_time) {
                             // Heartbeat successful
-                            last_heartbeat_mod_time = heartbeat_stat.st_mtime;
-                            last_heartbeat_elapsed_time = elapsed_time;
                             backtoback_heartbeat_failure = 1;
                         } else {
                             // Timestamps are not always monotonuous
@@ -1111,6 +1109,8 @@ int main(int argc, char** argv) {
                     boinc_finish(return_code);
                 }
 
+                last_heartbeat_mod_time = heartbeat_stat.st_mtime;
+                last_heartbeat_elapsed_time = elapsed_time;
                 initial_heartbeat_check = false;
             }
         }