Re-applied test update to support OS's that dont support using

  USR1 & USR2; replaced with HUP and INT for OS's (Windows)

Confirmed that the Perl Interrupt patch and it's alternative work
suitably well at protecting against the SEGV caused by Oracle
instant client non-Perl worker threads.

Author: ancientwizard

t/91-segv-fork.t

@@ -101,6 +101,7 @@ package DB::Fork;
 
 use strict;
 use warnings;
+use Carp;
 use Time::HiRes qw| usleep |;
 use DBI;
 use Test::More;
@@ -109,12 +110,13 @@ use Data::Dumper;
 use lib 't/lib';
 use DBDOracleTestLib qw/ db_handle /;
 
-
 our $VERSION;
 our $VERBOSE;
 our $ENABLED;
 our $CHILDREN;
 our $PARENT;
+our $SIG_PING;
+our $SIG_EXIT;
 
 our $ONETHR :shared;
 
@@ -123,6 +125,27 @@ BEGIN {
   $VERBOSE  = $main::VERBOSE || 0;
   $CHILDREN = [];
   $PARENT   = $$;
+  $SIG_PING = 'USR1';
+  $SIG_EXIT = 'USR2';
+
+  eval {
+    local $SIG{__WARN__} = sub
+    {
+      croak @_;
+    };
+
+    ## Not all OS's support USR1 / USR2
+    $SIG_PING = 'USR1';
+    $SIG_EXIT = 'USR2';
+    local $SIG{$SIG_PING} = sub { 1; };
+    local $SIG{$SIG_EXIT} = sub { 1; };
+  } or
+  do {
+    note "# Using HUP as alternative to unsupported USR1 (PING/ACK)\n";
+    note "# Using INT as alternative to unsupported USR2 (EXIT)\n";
+    $SIG_PING = 'HUP';
+    $SIG_EXIT = 'INT';
+  };
 
 # DBI->trace(9);
 }
@@ -204,7 +227,7 @@ sub ping
   my $olimit = 3 * scalar @ $CHILDREN;
   my $signaled = {};
 
-  local $SIG{USR1} = sub
+  local $SIG{$SIG_PING} = sub
   {
     return unless $child_pid;
     $signaled->{$child_pid} = $child_pid;
@@ -222,9 +245,9 @@ sub ping
 
     last unless $child_pid;
 
-    ## USR1 == ping
+    ## ping
     usleep 100000;
-    ok kill( 'USR1', $child_pid ), 'kill USR1(ping) ' . $child_pid;
+    ok kill( $SIG_PING, $child_pid ), sprintf 'kill %s %d', $SIG_PING, $child_pid;
 
     while ( $limit-- && ! exists $signaled->{ $child_pid } )
     {
@@ -242,17 +265,17 @@ QUEUE_BACKEND:
   my $do_ping;
   my $do_exit;
 
-  sub _USER1 { printf "# USR1=PING on-child=%d received\n", $$; return ( $do_ping = 1 ); }
-  sub _USER2 { printf "# USR2=EXIT on-child=%d received\n", $$; return ( $do_exit = 1 ); }
+  sub _USER1 { printf "# %s=PING on-child=%d received\n", $SIG_PING, $$; return ( $do_ping = 1 ); }
+  sub _USER2 { printf "# %s=EXIT on-child=%d received\n", $SIG_EXIT, $$; return ( $do_exit = 1 ); }
 
   sub _FORK_WORKER
   {
     $do_ping = $do_exit = 0;
 
     printf "# PID=%d (START)\n", $$;
 
-    local $SIG{USR1} = \&_USER1;
-    local $SIG{USR2} = \&_USER2;
+    local $SIG{$SIG_PING} = \&_USER1;
+    local $SIG{$SIG_EXIT} = \&_USER2;
 
     BUSY:
     while (1)
@@ -262,7 +285,8 @@ QUEUE_BACKEND:
       {
         printf "# pid=%s PING received (hold on, this is going to be a bumpy ride!)\n", $$;
         _connect();
-        printf "# PARENT=%s CHILD=%d %s=kill USR1\n", $PARENT, $$, kill( 'USR1', $PARENT );
+        ## AKA PING-ACK
+        printf "# PARENT=%s CHILD=%d %s=kill %s\n", $PARENT, $$, kill( $SIG_PING, $PARENT ), $SIG_PING;
         $do_ping = 0;
         next;
       }

t/92-segv-fork.pl

@@ -51,7 +51,7 @@
 exit(6) unless scalar @ $row == 1;
 # printf "# [ %s ]\n", $row->[];
 
-my $usleep = int(rand(300000)) + 2000000; # 2-5 seconds
+my $usleep = int(rand(100000)) + 2000000; # 1-3 seconds (to speed up test!)
 # printf "# %02.2f seconds\n", $usleep / 1000000;
 usleep($usleep);
 

t/92-segv-fork.t

@@ -1,5 +1,13 @@
 #!/usr/bin/env perl
 
+## A SEGV during this test is a sign that Perl itself lacks the patch
+##  that allows a SIGCHLD (any interrupt) to be handedled using a worker
+##  thread created by Oracle Instant Client.
+##
+## Consult: https://github.com/perl5-dbi/DBD-Oracle/issues/192
+##     and: https://github.com/Perl/perl5/issues/23326
+##  for details concerning the issue and the patch.
+
 use strict;
 use warnings;
 use Time::HiRes qw| usleep |;
@@ -107,12 +115,10 @@ QUEUE_BASICS:
 
 FORK_SEGV:
 {
-# last FORK_SEGV if 1;
-
   section 'FORK - SEGV';
 
   my $queue = Child::Queue->new( -DEPTH => 8 );
-  my $jobs  = 80;
+  my $jobs  = 40;
 
   is  $queue->depth,     8, 'Queue depth';
   is  $queue->size,      0, 'Queue size';