perf tools: Fail properly in case pattern matching fails to find tracepoint

Currently we dont fail properly when pattern matching fails to find any
tracepoint.

Current behaviour:

  $ perf record -e 'sched:krava*' sleep 1
  WARNING: event parser found nothinginvalid or unsupported event: 'sched:krava*'
  Run 'perf list' for a list of valid events

  usage: perf record [<options>] [<command>]
     or: perf record [<options>] -- <command> [<options>]

This patch change:

  $ perf record -e 'sched:krava*' sleep 1
  event syntax error: 'sched:krava*'
                       \___ unknown tracepoint

  Error:  File /sys/kernel/debug/tracing/events/sched/krava* not found.
  Hint:   Perhaps this kernel misses some CONFIG_ setting to enable this feature?.

  Run 'perf list' for a list of valid events

   usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

Reported-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1444073477-3181-1-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/parse-events.c

@@ -449,7 +449,7 @@ static int add_tracepoint_multi_event(struct list_head *list, int *idx,
 	char evt_path[MAXPATHLEN];
 	struct dirent *evt_ent;
 	DIR *evt_dir;
-	int ret = 0;
+	int ret = 0, found = 0;
 
 	snprintf(evt_path, MAXPATHLEN, "%s/%s", tracing_events_path, sys_name);
 	evt_dir = opendir(evt_path);
@@ -468,10 +468,17 @@ static int add_tracepoint_multi_event(struct list_head *list, int *idx,
 		if (!strglobmatch(evt_ent->d_name, evt_name))
 			continue;
 
+		found++;
+
 		ret = add_tracepoint(list, idx, sys_name, evt_ent->d_name,
 				     err, head_config);
 	}
 
+	if (!found) {
+		tracepoint_error(err, ENOENT, sys_name, evt_name);
+		ret = -1;
+	}
+
 	closedir(evt_dir);
 	return ret;
 }