perf parse: Add parse events handle error

Parse event error handling may overwrite one error string with another
creating memory leaks. Introduce a helper routine that warns about
multiple error messages as well as avoiding the memory leak.

A reproduction of this problem can be seen with:

  perf stat -e c/c/

After this change this produces:
WARNING: multiple event parsing errors
event syntax error: 'c/c/'
                       \___ unknown term

valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore
Run 'perf list' for a list of valid events

 Usage: perf stat [<options>] [<command>]

    -e, --event <event>   event selector. use 'perf list' to list available events

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20191030223448.12930-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 18 insertions, 12 deletions

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index adbe97e941dd..f9f427d4c313 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1050,9 +1050,9 @@ static int pmu_config_term(struct list_head *formats,
 		if (err) {
 			char *pmu_term = pmu_formats_string(formats);
 
-			err->idx  = term->err_term;
-			err->str  = strdup("unknown term");
-			err->help = parse_events_formats_error_string(pmu_term);
+			parse_events__handle_error(err, term->err_term,
+				strdup("unknown term"),
+				parse_events_formats_error_string(pmu_term));
 			free(pmu_term);
 		}
 		return -EINVAL;
@@ -1080,8 +1080,9 @@ static int pmu_config_term(struct list_head *formats,
 		if (term->no_value &&
 		    bitmap_weight(format->bits, PERF_PMU_FORMAT_BITS) > 1) {
 			if (err) {
-				err->idx = term->err_val;
-				err->str = strdup("no value assigned for term");
+				parse_events__handle_error(err, term->err_val,
+					   strdup("no value assigned for term"),
+					   NULL);
 			}
 			return -EINVAL;
 		}
@@ -1094,8 +1095,9 @@ static int pmu_config_term(struct list_head *formats,
 						term->config, term->val.str);
 			}
 			if (err) {
-				err->idx = term->err_val;
-				err->str = strdup("expected numeric value");
+				parse_events__handle_error(err, term->err_val,
+					strdup("expected numeric value"),
+					NULL);
 			}
 			return -EINVAL;
 		}
@@ -1108,11 +1110,15 @@ static int pmu_config_term(struct list_head *formats,
 	max_val = pmu_format_max_value(format->bits);
 	if (val > max_val) {
 		if (err) {
-			err->idx = term->err_val;
-			if (asprintf(&err->str,
-				     "value too big for format, maximum is %llu",
-				     (unsigned long long)max_val) < 0)
-				err->str = strdup("value too big for format");
+			char *err_str;
+
+			parse_events__handle_error(err, term->err_val,
+				asprintf(&err_str,
+				    "value too big for format, maximum is %llu",
+				    (unsigned long long)max_val) < 0
+				    ? strdup("value too big for format")
+				    : err_str,
+				    NULL);
 			return -EINVAL;
 		}
 		/*