Add sigtest to check signal mask

sigtest.c

@@ -0,0 +1,66 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <setjmp.h>
+
+const int SIGNAL_TYPE = SIGSEGV;
+
+// Global flag and jump buffer for recovery
+static jmp_buf env_buffer;
+static volatile int handled = 0;
+
+void handler(int signal_num) {
+  handled += 1;
+  longjmp(env_buffer, 1);
+}
+
+int trigger() {
+  if(setjmp(env_buffer)) {
+    return 1;
+  }
+  //volatile char _ = *((char*)0);
+  raise(SIGNAL_TYPE);
+  return 0;
+}
+
+int printSigMasks() {
+  sigset_t set;
+  // Get the current signal mask
+  if (sigprocmask(SIG_BLOCK, NULL, &set) == -1) {
+      perror("sigprocmask");
+      return 1;
+  }
+  // Print blocked signal masks
+  int blocked = 0;
+  for (int i = 1; i < NSIG; ++i) {
+      if (sigismember(&set, i)) {
+          blocked += 1;
+          printf("Signal %d is blocked\n", i);
+      }
+  }
+  if(!blocked) {
+    printf("No blocked signals\n");
+  }
+  return 0;
+}
+
+int main(int argc, char *argv[]) {
+  printf("NSIG = %i\n", NSIG);
+
+  void* sig_res = signal(SIGNAL_TYPE, handler);
+  if(sig_res == SIG_ERR) {
+    printf("Error setting signal handler\n");
+    exit(EXIT_FAILURE);
+  }
+  
+  int result = 0;
+  printSigMasks();
+  result = trigger();
+  printf("Raised = %i\tHandled = %i\n", result, handled);
+  printSigMasks();
+  result = trigger();
+  printf("Raised = %i\tHandled = %i\n", result, handled);
+  printSigMasks();
+
+  return EXIT_SUCCESS;
+}