tcptop: Cleanup argument parsing

tools/tcptop.py

@@ -34,6 +34,13 @@
 import ctypes as ct
 
 # arguments
+def range_check(string):
+ value = int(string)
+ if value < 1:
+ msg = "value must be stricly positive, got %d" % (value,)
+ raise argparse.ArgumentTypeError(msg)
+ return value
+
 examples = """examples:
  ./tcptop # trace TCP send/recv by host
  ./tcptop -C # don't clear the screen
@@ -49,15 +56,11 @@
  help="skip system summary line")
 parser.add_argument("-p", "--pid",
  help="trace this PID only")
-parser.add_argument("interval", nargs="?", default=1,
+parser.add_argument("interval", nargs="?", default=1, type=range_check,
  help="output interval, in seconds (default 1)")
-parser.add_argument("count", nargs="?", default=99999999,
+parser.add_argument("count", nargs="?", default=-1, type=range_check,
  help="number of outputs")
 args = parser.parse_args()
-countdown = int(args.count)
-if args.interval and int(args.interval) == 0:
- print("ERROR: interval 0. Exiting.")
- exit()
 debug = 0
 
 # linux stats
@@ -204,15 +207,13 @@ def pid_to_comm(pid):
 print('Tracing... Output every %s secs. Hit Ctrl-C to end' % args.interval)
 
 # output
-exiting = 0
-while (1):
+i = 0
+exiting = False
+while i != args.count and not exiting:
  try:
- if args.interval:
- sleep(int(args.interval))
- else:
- sleep(99999999)
+ sleep(args.interval)
  except KeyboardInterrupt:
- exiting = 1
+ exiting = True
 
  # header
  if args.noclear:
@@ -282,6 +283,4 @@ def pid_to_comm(pid):
  ipv6_send_bytes.clear()
  ipv6_recv_bytes.clear()
 
- countdown -= 1
- if exiting or countdown == 0:
- exit()
+ i += 1