Instead of piped opens, you might want to try pipes with threads, for example Using Select and pipes to communicate with threads. That way you have more control over the pipes and any timer alarm threads you might setup. A way to run parallel threads, one as an alarm timer can be done, but it is frought with details about signal chains. On linux the signals are received by the parent thread first, then echo'd out to the child threads.

#!/usr/bin/perl -w
use strict;
use threads;
use threads::shared;

my $timer_go:shared = 0;

my $worker = threads->create(\&worker);
my $timer = threads->create(\&timer,$worker)->detach();

print "hit enter to start\n";
<>;
$timer_go=1;


while( (scalar threads->list) > 0   ){
 print scalar threads->list,"\n"; 
 sleep 1;
foreach my $thread (threads->list) {
   if( $thread->is_joinable ){ $thread->join;}
   }
}

print "worker joined, all done\n";
exit;


sub timer {
  my $worker = shift;
   while(1){     
       if($timer_go){
        my $count = 0;
             while(1){ 
                  $count++;
                  if($count > 5){    
                         print "timed out\n";
                          # Send a signal to a thread
                         $worker->kill('INT');
                         return; # will destroy a detached thread
                        } 
                  sleep 1;
                  print "timing $count\n";
            }
       }else{sleep 1}
    }
}

sub worker {
       $|++;
       $SIG{INT} = sub{ warn "Caught Zap!\n"; threads->exit() };
       # threads->exit() will exit thread only
       

      while(1){sleep 1;  next}

      return;
}
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