TT#75114 prevent exit() invocations

Change-Id: If6c1049b842b44706c076e9e39ee7d42de4a43b5

lib/NGCP/Panel/Utils/ProvisioningTemplates.pm

@@ -28,6 +28,19 @@ use NGCP::Panel::Utils::Subscriber qw();
 use NGCP::Panel::Utils::Preferences qw();
 use NGCP::Panel::Utils::Kamailio qw();
 
+#The function _calculate() evaluates perl code provided via a configuration
+#by the user, so we must make sure no such code will call exit() by
+#accident or we would terminate the entire program.
+our $DISABLE_EXIT = 0;
+BEGIN {
+    *CORE::GLOBAL::exit = sub (;$) {
+        ## no critic (TestingAndDebugging::ProhibitNoWarnings)
+        no warnings 'exiting';
+        die('exit() called') if $DISABLE_EXIT;
+        CORE::exit($_[0] // 0);
+    };
+}
+
 my $IDENTIFIER_FNAME = 'identifier';
 my $CODE_SUFFIX_FNAME = '_code';
 my $FIELD_TYPE_ATTRIBUTE = 'type';
@@ -997,6 +1010,7 @@ sub _calculate {
     $context->{cr_c} //= {};
     if ($f =~ /^([a-z0-9_]+)$CODE_SUFFIX_FNAME$/) {
         my $cl;
+        local $DISABLE_EXIT = 1;
         if ($strict_closure) {
             $cl = eval_closure(
                 source      => $c,