selftests/bpf: add veristat replay mode

Replay mode allow to parse previously stored CSV file with verification
results and present it in desired output (presumable human-readable
table, but CSV to CSV convertion is supported as well). While doing
that, it's possible to use veristat's sorting rules, specify subset of
columns, and filter by file and program name.

In subsequent patches veristat's filtering capabilities will just grow
making replay mode even more useful in practice for post-processing
results.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/veristat.c

@@ -67,6 +67,7 @@ static struct env {
 	int log_level;
 	enum resfmt out_fmt;
 	bool comparison_mode;
+	bool replay_mode;
 
 	struct verif_stats *prog_stats;
 	int prog_stat_cnt;
@@ -115,6 +116,7 @@ static const struct argp_option opts[] = {
 	{ "sort", 's', "SPEC", 0, "Specify sort order" },
 	{ "output-format", 'o', "FMT", 0, "Result output format (table, csv), default is table." },
 	{ "compare", 'C', NULL, 0, "Comparison mode" },
+	{ "replay", 'R', NULL, 0, "Replay mode" },
 	{ "filter", 'f', "FILTER", 0, "Filter expressions (or @filename for file with expressions)." },
 	{},
 };
@@ -169,6 +171,9 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
 	case 'C':
 		env.comparison_mode = true;
 		break;
+	case 'R':
+		env.replay_mode = true;
+		break;
 	case 'f':
 		if (arg[0] == '@')
 			err = append_filter_file(arg + 1);
@@ -841,42 +846,6 @@ static void output_stats(const struct verif_stats *s, enum resfmt fmt, bool last
 	}
 }
 
-static int handle_verif_mode(void)
-{
-	int i, err;
-
-	if (env.filename_cnt == 0) {
-		fprintf(stderr, "Please provide path to BPF object file!\n");
-		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
-		return -EINVAL;
-	}
-
-	for (i = 0; i < env.filename_cnt; i++) {
-		err = process_obj(env.filenames[i]);
-		if (err) {
-			fprintf(stderr, "Failed to process '%s': %d\n", env.filenames[i], err);
-			return err;
-		}
-	}
-
-	qsort(env.prog_stats, env.prog_stat_cnt, sizeof(*env.prog_stats), cmp_prog_stats);
-
-	if (env.out_fmt == RESFMT_TABLE) {
-		/* calculate column widths */
-		output_headers(RESFMT_TABLE_CALCLEN);
-		for (i = 0; i < env.prog_stat_cnt; i++)
-			output_stats(&env.prog_stats[i], RESFMT_TABLE_CALCLEN, false);
-	}
-
-	/* actually output the table */
-	output_headers(env.out_fmt);
-	for (i = 0; i < env.prog_stat_cnt; i++) {
-		output_stats(&env.prog_stats[i], env.out_fmt, i == env.prog_stat_cnt - 1);
-	}
-
-	return 0;
-}
-
 static int parse_stat_value(const char *str, enum stat_id id, struct verif_stats *st)
 {
 	switch (id) {
@@ -1206,7 +1175,7 @@ static int handle_comparison_mode(void)
 	int err, i, j;
 
 	if (env.filename_cnt != 2) {
-		fprintf(stderr, "Comparison mode expects exactly two input CSV files!\n");
+		fprintf(stderr, "Comparison mode expects exactly two input CSV files!\n\n");
 		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
 		return -EINVAL;
 	}
@@ -1307,6 +1276,79 @@ static int handle_comparison_mode(void)
 	return 0;
 }
 
+static void output_prog_stats(void)
+{
+	const struct verif_stats *stats;
+	int i, last_stat_idx = 0;
+
+	if (env.out_fmt == RESFMT_TABLE) {
+		/* calculate column widths */
+		output_headers(RESFMT_TABLE_CALCLEN);
+		for (i = 0; i < env.prog_stat_cnt; i++) {
+			stats = &env.prog_stats[i];
+			output_stats(stats, RESFMT_TABLE_CALCLEN, false);
+			last_stat_idx = i;
+		}
+	}
+
+	/* actually output the table */
+	output_headers(env.out_fmt);
+	for (i = 0; i < env.prog_stat_cnt; i++) {
+		stats = &env.prog_stats[i];
+		output_stats(stats, env.out_fmt, i == last_stat_idx);
+	}
+}
+
+static int handle_verif_mode(void)
+{
+	int i, err;
+
+	if (env.filename_cnt == 0) {
+		fprintf(stderr, "Please provide path to BPF object file!\n\n");
+		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < env.filename_cnt; i++) {
+		err = process_obj(env.filenames[i]);
+		if (err) {
+			fprintf(stderr, "Failed to process '%s': %d\n", env.filenames[i], err);
+			return err;
+		}
+	}
+
+	qsort(env.prog_stats, env.prog_stat_cnt, sizeof(*env.prog_stats), cmp_prog_stats);
+
+	output_prog_stats();
+
+	return 0;
+}
+
+static int handle_replay_mode(void)
+{
+	struct stat_specs specs = {};
+	int err;
+
+	if (env.filename_cnt != 1) {
+		fprintf(stderr, "Replay mode expects exactly one input CSV file!\n\n");
+		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
+		return -EINVAL;
+	}
+
+	err = parse_stats_csv(env.filenames[0], &specs,
+			      &env.prog_stats, &env.prog_stat_cnt);
+	if (err) {
+		fprintf(stderr, "Failed to parse stats from '%s': %d\n", env.filenames[0], err);
+		return err;
+	}
+
+	qsort(env.prog_stats, env.prog_stat_cnt, sizeof(*env.prog_stats), cmp_prog_stats);
+
+	output_prog_stats();
+
+	return 0;
+}
+
 int main(int argc, char **argv)
 {
 	int err = 0, i;
@@ -1315,7 +1357,7 @@ int main(int argc, char **argv)
 		return 1;
 
 	if (env.verbose && env.quiet) {
-		fprintf(stderr, "Verbose and quiet modes are incompatible, please specify just one or neither!\n");
+		fprintf(stderr, "Verbose and quiet modes are incompatible, please specify just one or neither!\n\n");
 		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
 		return 1;
 	}
@@ -1327,8 +1369,16 @@ int main(int argc, char **argv)
 	if (env.sort_spec.spec_cnt == 0)
 		env.sort_spec = default_sort_spec;
 
+	if (env.comparison_mode && env.replay_mode) {
+		fprintf(stderr, "Can't specify replay and comparison mode at the same time!\n\n");
+		argp_help(&argp, stderr, ARGP_HELP_USAGE, "veristat");
+		return 1;
+	}
+
 	if (env.comparison_mode)
 		err = handle_comparison_mode();
+	else if (env.replay_mode)
+		err = handle_replay_mode();
 	else
 		err = handle_verif_mode();