tuna: tuna-cmd: Display usage instead of traceback -c missing args

Display a usage messaage instead of a python traceback when a required
argument to the -c or --cpus is missing, or when the argument doesn't
make sense. (Such as passing a nonsense string, instead of a comma separated list of numbers)

- In function pick_op, handle the unusual but possible case where an
  empty string is passed as an argument.
- Display a usage message upon ValueError when caling cpustring_to_list
  when processing the -c option

This fixes various erroneous or missing input to -c, such as the
following

./tuna-cmd.py -c -P
Traceback (most recent call last):
  File "./tuna-cmd.py", line 656, in <module>
    main()
  File "./tuna-cmd.py", line 494, in main
    op_list = tuna.cpustring_to_list(a)
  File "/home/jkacur/source/tuna/tuna/tuna.py", line 124, in
cpustring_to_list
    ends = [ int(a, 0) for a in field.split("-") ]
ValueError: invalid literal for int() with base 0: 'P'

./tuna-cmd.py -c "" -P
Traceback (most recent call last):
  File "./tuna-cmd.py", line 656, in <module>
    main()
  File "./tuna-cmd.py", line 493, in main
    (op, a) = pick_op(a)
  File "./tuna-cmd.py", line 408, in pick_op
    if argument[0] in ('+', '-'):
IndexError: string index out of range

./tuna-cmd.py -c "nonesense" -P
Traceback (most recent call last):
  File "./tuna-cmd.py", line 656, in <module>
    main()
  File "./tuna-cmd.py", line 494, in main
    op_list = tuna.cpustring_to_list(a)
  File "/home/jkacur/source/tuna/tuna/tuna.py", line 124, in
cpustring_to_list
    ends = [ int(a, 0) for a in field.split("-") ]
ValueError: invalid literal for int() with base 0: 'nonesense'

This fixes bugzilla 1268287

Signed-off-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Jiri Kastner <jkastner@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/tuna-cmd.py b/tuna-cmd.py
index ae4f78a..3c9bfaa 100755
--- a/tuna-cmd.py
+++ b/tuna-cmd.py
@@ -405,6 +405,8 @@ def irq_mapper(s):
 	return irq_list
 
 def pick_op(argument):
+        if argument == "":
+                return (None, argument)
 	if argument[0] in ('+', '-'):
 		return (argument[0], argument[1:])
 	return (None, argument)
@@ -491,7 +493,11 @@ def main():
 			list_config()
 		elif o in ("-c", "--cpus"):
 			(op, a) = pick_op(a)
-			op_list = tuna.cpustring_to_list(a)
+                        try:
+			    op_list = tuna.cpustring_to_list(a)
+                        except ValueError:
+                            usage()
+                            return
 			cpu_list = do_list_op(op, cpu_list, op_list)
 		elif o in ("-N", "--nohz_full"):
 			try: