fail2ban-regex: don't error by output if stdout pipe gets closed (e…

…. g. using together with `head`);

amend to gh-2758 (see gh-3653)

fail2ban/client/fail2banregex.py

@@ -789,7 +789,15 @@ def start(self, args):
  return True
 
 
+def _loc_except_hook(exctype, value, traceback):
+ if (exctype != BrokenPipeError and exctype != IOError or value.errno != 32):
+ return sys.__excepthook__(exctype, value, traceback)
+ # pipe seems to be closed (head / tail / etc), thus simply exit:
+ sys.exit(0)
+
 def exec_command_line(*args):
+ sys.excepthook = _loc_except_hook; # stop on closed/broken pipe
+
  logging.exitOnIOError = True
  parser = get_opt_parser()
  (opts, args) = parser.parse_args(*args)