More elegantly handle SIGINT

CHANGELOG.md

@@ -29,6 +29,7 @@
 
 
 ### Changed (changing behavior/API/variables/...)
+- [[PR 782]](https://github.com/parthenon-hpc-lab/parthenon/pull/782) Die on repeatedly receiving SIGINT
 - [[PR 1438]](https://github.com/parthenon-hpc-lab/parthenon/pull/1438) Performance tuning for the loop abstraction machinery and add loop abstraction OpenMP support
 - [[PR 1416][(https://github.com/parthenon-hpc-lab/parthenon/pull/1416) Remove virtual tag from destructors in sparse and swarm pack base classes
 - [[PR 1401]](https://github.com/parthenon-hpc-lab/parthenon/pull/1401) Sparse Field Component Names

src/utils/signal_handler.cpp

@@ -23,6 +23,7 @@
 
 // first 2x macros and signal() are the only ISO C features; rest are POSIX C extensions
 #include <csignal>
+#include <filesystem>
 #include <iostream>
 
 #include FS_HEADER
@@ -132,15 +133,17 @@ void SetSignalFlag(int s) {
   // Signal handler functions must have C linkage; C++ linkage is implemantation-defined
   switch (s) {
   case SIGTERM:
-    signalflag[ITERM] = 1;
+    signalflag[ITERM] += 1;
     signal(s, SetSignalFlag);
     break;
   case SIGINT:
-    signalflag[IINT] = 1;
+    signalflag[IINT] += 1;
+    if (signalflag[IINT] >= SIGINTS_BEFORE_THROW)
+      PARTHENON_THROW("Terminating immediately on repeated Terminate signal");
     signal(s, SetSignalFlag);
     break;
   case SIGALRM:
-    signalflag[IALRM] = 1;
+    signalflag[IALRM] += 1;
     signal(s, SetSignalFlag);
     break;
   default:

src/utils/utils.hpp

@@ -91,11 +91,18 @@ void WatchDog(int timeout);
 //  \brief static data and functions that implement a simple signal handling system
 namespace SignalHandler {
 
+// Enum of desired signal results
 enum class OutputSignal { none, now, final, analysis };
+// Signals handled: SIGTERM, SIGINT, SIGALRM
+constexpr int ITERM = 0, IINT = 1, IALRM = 2;
 constexpr int nsignal = 3;
-// using the +1 for signaling based on "output_now" trigger
+// Flag/counter of signals received of each type
+// using the +1 for signaling based on a trigger file
 static volatile int signalflag[nsignal + 1];
-const int ITERM = 0, IINT = 1, IALRM = 2;
+
+// Immediately throw upon receiving 3+ SIGINT without clearing them
+constexpr int SIGINTS_BEFORE_THROW = 3;
+
 static sigset_t mask;
 void SignalHandlerInit();
 OutputSignal CheckSignalFlags();