perf probe: Check hyphen only argument

Check hyphen only command argument, because perf-probe doesn't
support event recording feature yet.

e.g.

 # perf probe -
  Error: '-' is not supported.

Signed-off-by: Masami Hiramatsu <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Jim Keniston <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Frank Ch. Eigler <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: K.Prasad <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Srikar Dronamraju <[email protected]>
Cc: systemtap <[email protected]>
Cc: DLE <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

tools/perf/builtin-probe.c

@@ -205,8 +205,13 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 
 	argc = parse_options(argc, argv, options, probe_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
-	if (argc > 0)
+	if (argc > 0) {
+		if (strcmp(argv[0], "-") == 0) {
+			pr_warning("  Error: '-' is not supported.\n");
+			usage_with_options(probe_usage, options);
+		}
 		parse_probe_event_argv(argc, argv);
+	}
 
 	if ((!session.nr_probe && !session.dellist && !session.list_events))
 		usage_with_options(probe_usage, options);