[PATCH v13 21/32] perf evsel: Don't pass evsel with sample

[Ian Rogers <irogers@google.com>]

Arrange for the sample to contain the evsel and so it is unnecessary
to pass the evsel as well. This is done for uniformity, although
parsing of the sample is arguably a special case. Add bound checks in
perf_evsel__parse_id_sample by switching to using an index and
checking it doesn't become negative.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/evsel.c | 61 +++++++++++++++++++++++++----------------
 1 file changed, 37 insertions(+), 24 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ee30e15af054..bb48568b8101 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -3003,52 +3003,62 @@ int evsel__open_per_thread(struct evsel *evsel, struct perf_thread_map *threads)
 	return ret;
 }
 
-static int perf_evsel__parse_id_sample(const struct evsel *evsel,
-				       const union perf_event *event,
+static int perf_evsel__parse_id_sample(const union perf_event *event,
 				       struct perf_sample *sample)
 {
+	const struct evsel *evsel = sample->evsel;
 	u64 type = evsel->core.attr.sample_type;
 	const __u64 *array = event->sample.array;
 	bool swapped = evsel->needs_swap;
 	union u64_swap u;
-
-	array += ((event->header.size -
-		   sizeof(event->header)) / sizeof(u64)) - 1;
+	int i = ((event->header.size - sizeof(event->header)) / sizeof(u64)) - 1;
 
 	if (type & PERF_SAMPLE_IDENTIFIER) {
-		sample->id = *array;
-		array--;
+		if (i < 0)
+			return -EFAULT;
+
+		sample->id = array[i--];
 	}
 
 	if (type & PERF_SAMPLE_CPU) {
-		u.val64 = *array;
+		if (i < 0)
+			return -EFAULT;
+
+		u.val64 = array[i--];
 		if (swapped) {
 			/* undo swap of u64, then swap on individual u32s */
 			u.val64 = bswap_64(u.val64);
 			u.val32[0] = bswap_32(u.val32[0]);
 		}
-
 		sample->cpu = u.val32[0];
-		array--;
 	}
 
 	if (type & PERF_SAMPLE_STREAM_ID) {
-		sample->stream_id = *array;
-		array--;
+		if (i < 0)
+			return -EFAULT;
+
+		sample->stream_id = array[i--];
 	}
 
 	if (type & PERF_SAMPLE_ID) {
-		sample->id = *array;
-		array--;
+		if (i < 0)
+			return -EFAULT;
+
+		sample->id = array[i--];
 	}
 
 	if (type & PERF_SAMPLE_TIME) {
-		sample->time = *array;
-		array--;
+		if (i < 0)
+			return -EFAULT;
+
+		sample->time = array[i--];
 	}
 
 	if (type & PERF_SAMPLE_TID) {
-		u.val64 = *array;
+		if (i < 0)
+			return -EFAULT;
+
+		u.val64 = array[i--];
 		if (swapped) {
 			/* undo swap of u64, then swap on individual u32s */
 			u.val64 = bswap_64(u.val64);
@@ -3058,7 +3068,6 @@ static int perf_evsel__parse_id_sample(const struct evsel *evsel,
 
 		sample->pid = u.val32[0];
 		sample->tid = u.val32[1];
-		array--;
 	}
 
 	return 0;
@@ -3244,15 +3253,18 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
 
 		data->deferred_cookie = event->callchain_deferred.cookie;
 
-		if (evsel->core.attr.sample_id_all)
-			perf_evsel__parse_id_sample(evsel, event, data);
-
+		if (evsel->core.attr.sample_id_all) {
+			if (perf_evsel__parse_id_sample(event, data))
+				goto out_efault;
+		}
 		return 0;
 	}
 
 	if (event->header.type != PERF_RECORD_SAMPLE) {
-		if (evsel->core.attr.sample_id_all)
-			perf_evsel__parse_id_sample(evsel, event, data);
+		if (evsel->core.attr.sample_id_all) {
+			if (perf_evsel__parse_id_sample(event, data))
+				goto out_efault;
+		}
 		return 0;
 	}
 
@@ -3614,12 +3626,13 @@ int evsel__parse_sample_timestamp(struct evsel *evsel, union perf_event *event,
 
 	if (event->header.type != PERF_RECORD_SAMPLE) {
 		struct perf_sample data = {
+			.evsel = evsel,
 			.time = -1ULL,
 		};
 
 		if (!evsel->core.attr.sample_id_all)
 			return -1;
-		if (perf_evsel__parse_id_sample(evsel, event, &data))
+		if (perf_evsel__parse_id_sample(event, &data))
 			return -1;
 
 		*timestamp = data.time;
-- 
2.54.0.563.g4f69b47b94-goog