[PATCH 1/4] perf trace: Improve error message when receive non-tracepoint events

[Wang Nan <wangnan0@huawei.com>]

Before this patch, strange error message is provided if passed a
non-tracepoint event to 'perf trace':

 # perf trace -a  --ev cycles sleep 1
 Failed to set filter "common_pid != 27500" on event cycles with 22 (Invalid argument)

This is because 'perf trace' accepts all valid events during cmdline
parsing, but in fact user can only provide tracepoints, because it
needs filter.

This patch validate evlist, report error earlier:

 # ./perf trace -a  --ev cycles sleep 1
 Only support tracepoint events!

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/builtin-trace.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 11290b5..6fbed86 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2680,6 +2680,17 @@ out_enomem:
 	goto out;
 }
 
+static int validate_evlist(struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+
+	evlist__for_each(evlist, evsel) {
+		if (evsel->attr.type != PERF_TYPE_TRACEPOINT)
+			return -EINVAL;
+	}
+	return 0;
+}
+
 static int trace__run(struct trace *trace, int argc, const char **argv)
 {
 	struct perf_evlist *evlist = trace->evlist;
@@ -3273,6 +3284,11 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 	argc = parse_options_subcommand(argc, argv, trace_options, trace_subcommands,
 				 trace_usage, PARSE_OPT_STOP_AT_NON_OPTION);
 
+	if (validate_evlist(trace.evlist)) {
+		pr_err("Only support tracepoint events!\n");
+		return -EINVAL;
+	}
+
 	if (trace.trace_pgfaults) {
 		trace.opts.sample_address = true;
 		trace.opts.sample_time = true;
-- 
1.8.3.4