MYLOOP: while ( 1 ) {

   open my $fh1, '<', "$file1" or foobar($file1);
   # irgendeine Verarbeitung
   close $fh1;

   open my $fh2, '<', "$file2" or foobar($file2);
   # irgendeine Verarbeitung
   close $fh2;

   open my $fh3, '<', "$file3" or foobar($file3);
   # irgendeine Verarbeitung
   close $fh3;

}

sub foobar {
   my $file = shift;
   print STDERR "unable to open $file: $!\n";
   print STDERR "sleep for 3 seconds\n";
   sleep 3;
   print STDERR "wakeup\n";

   {
      no warnings "exiting";
      next MYLOOP;
   }
}