selftests/bpf: abstract away test log output

This patch changes how test output is printed out. By default, if test
had no errors, the only output will be a single line with test number,
name, and verdict at the end, e.g.:

  #31 xdp:OK

If test had any errors, all log output captured during test execution
will be output after test completes.

It's possible to force output of log with `-v` (`--verbose`) option, in
which case output won't be buffered and will be output immediately.

To support this, individual tests are required to use helper methods for
logging: `test__printf()` and `test__vprintf()`.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c

@@ -106,8 +106,8 @@ void test_bpf_obj_id(void)
 		if (CHECK(err ||
 			  prog_infos[i].type != BPF_PROG_TYPE_SOCKET_FILTER ||
 			  info_len != sizeof(struct bpf_prog_info) ||
-			  (jit_enabled && !prog_infos[i].jited_prog_len) ||
-			  (jit_enabled &&
+			  (env.jit_enabled && !prog_infos[i].jited_prog_len) ||
+			  (env.jit_enabled &&
 			   !memcmp(jited_insns, zeros, sizeof(zeros))) ||
 			  !prog_infos[i].xlated_prog_len ||
 			  !memcmp(xlated_insns, zeros, sizeof(zeros)) ||
@@ -121,7 +121,7 @@ void test_bpf_obj_id(void)
 			  err, errno, i,
 			  prog_infos[i].type, BPF_PROG_TYPE_SOCKET_FILTER,
 			  info_len, sizeof(struct bpf_prog_info),
-			  jit_enabled,
+			  env.jit_enabled,
 			  prog_infos[i].jited_prog_len,
 			  prog_infos[i].xlated_prog_len,
 			  !!memcmp(jited_insns, zeros, sizeof(zeros)),

tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c

@@ -4,12 +4,15 @@
 static int libbpf_debug_print(enum libbpf_print_level level,
 			      const char *format, va_list args)
 {
-	if (level != LIBBPF_DEBUG)
-		return vfprintf(stderr, format, args);
+	if (level != LIBBPF_DEBUG) {
+		test__vprintf(format, args);
+		return 0;
+	}
 
 	if (!strstr(format, "verifier log"))
 		return 0;
-	return vfprintf(stderr, "%s", args);
+	test__vprintf("%s", args);
+	return 0;
 }
 
 static int check_load(const char *file, enum bpf_prog_type type)
@@ -73,32 +76,38 @@ void test_bpf_verif_scale(void)
 	libbpf_print_fn_t old_print_fn = NULL;
 	int err, i;
 
-	if (verifier_stats)
+	if (env.verifier_stats) {
+		test__force_log();
 		old_print_fn = libbpf_set_print(libbpf_debug_print);
+	}
 
 	err = check_load("./loop3.o", BPF_PROG_TYPE_RAW_TRACEPOINT);
-	printf("test_scale:loop3:%s\n", err ? (error_cnt--, "OK") : "FAIL");
+	test__printf("test_scale:loop3:%s\n",
+		     err ? (error_cnt--, "OK") : "FAIL");
 
 	for (i = 0; i < ARRAY_SIZE(sched_cls); i++) {
 		err = check_load(sched_cls[i], BPF_PROG_TYPE_SCHED_CLS);
-		printf("test_scale:%s:%s\n", sched_cls[i], err ? "FAIL" : "OK");
+		test__printf("test_scale:%s:%s\n", sched_cls[i],
+			     err ? "FAIL" : "OK");
 	}
 
 	for (i = 0; i < ARRAY_SIZE(raw_tp); i++) {
 		err = check_load(raw_tp[i], BPF_PROG_TYPE_RAW_TRACEPOINT);
-		printf("test_scale:%s:%s\n", raw_tp[i], err ? "FAIL" : "OK");
+		test__printf("test_scale:%s:%s\n", raw_tp[i],
+			     err ? "FAIL" : "OK");
 	}
 
 	for (i = 0; i < ARRAY_SIZE(cg_sysctl); i++) {
 		err = check_load(cg_sysctl[i], BPF_PROG_TYPE_CGROUP_SYSCTL);
-		printf("test_scale:%s:%s\n", cg_sysctl[i], err ? "FAIL" : "OK");
+		test__printf("test_scale:%s:%s\n", cg_sysctl[i],
+			     err ? "FAIL" : "OK");
 	}
 	err = check_load("./test_xdp_loop.o", BPF_PROG_TYPE_XDP);
-	printf("test_scale:test_xdp_loop:%s\n", err ? "FAIL" : "OK");
+	test__printf("test_scale:test_xdp_loop:%s\n", err ? "FAIL" : "OK");
 
 	err = check_load("./test_seg6_loop.o", BPF_PROG_TYPE_LWT_SEG6LOCAL);
-	printf("test_scale:test_seg6_loop:%s\n", err ? "FAIL" : "OK");
+	test__printf("test_scale:test_seg6_loop:%s\n", err ? "FAIL" : "OK");
 
-	if (verifier_stats)
+	if (env.verifier_stats)
 		libbpf_set_print(old_print_fn);
 }

tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c

@@ -41,7 +41,7 @@ static void get_stack_print_output(void *ctx, int cpu, void *data, __u32 size)
 		 * just assume it is good if the stack is not empty.
 		 * This could be improved in the future.
 		 */
-		if (jit_enabled) {
+		if (env.jit_enabled) {
 			found = num_stack > 0;
 		} else {
 			for (i = 0; i < num_stack; i++) {
@@ -58,7 +58,7 @@ static void get_stack_print_output(void *ctx, int cpu, void *data, __u32 size)
 		}
 	} else {
 		num_stack = e->kern_stack_size / sizeof(__u64);
-		if (jit_enabled) {
+		if (env.jit_enabled) {
 			good_kern_stack = num_stack > 0;
 		} else {
 			for (i = 0; i < num_stack; i++) {

tools/testing/selftests/bpf/prog_tests/l4lb_all.c

@@ -74,7 +74,7 @@ static void test_l4lb(const char *file)
 	}
 	if (bytes != MAGIC_BYTES * NUM_ITER * 2 || pkts != NUM_ITER * 2) {
 		error_cnt++;
-		printf("test_l4lb:FAIL:stats %lld %lld\n", bytes, pkts);
+		test__printf("test_l4lb:FAIL:stats %lld %lld\n", bytes, pkts);
 	}
 out:
 	bpf_object__close(obj);

tools/testing/selftests/bpf/prog_tests/map_lock.c

@@ -9,21 +9,21 @@ static void *parallel_map_access(void *arg)
 	for (i = 0; i < 10000; i++) {
 		err = bpf_map_lookup_elem_flags(map_fd, &key, vars, BPF_F_LOCK);
 		if (err) {
-			printf("lookup failed\n");
+			test__printf("lookup failed\n");
 			error_cnt++;
 			goto out;
 		}
 		if (vars[0] != 0) {
-			printf("lookup #%d var[0]=%d\n", i, vars[0]);
+			test__printf("lookup #%d var[0]=%d\n", i, vars[0]);
 			error_cnt++;
 			goto out;
 		}
 		rnd = vars[1];
 		for (j = 2; j < 17; j++) {
 			if (vars[j] == rnd)
 				continue;
-			printf("lookup #%d var[1]=%d var[%d]=%d\n",
-			       i, rnd, j, vars[j]);
+			test__printf("lookup #%d var[1]=%d var[%d]=%d\n",
+				     i, rnd, j, vars[j]);
 			error_cnt++;
 			goto out;
 		}
@@ -43,7 +43,7 @@ void test_map_lock(void)
 
 	err = bpf_prog_load(file, BPF_PROG_TYPE_CGROUP_SKB, &obj, &prog_fd);
 	if (err) {
-		printf("test_map_lock:bpf_prog_load errno %d\n", errno);
+		test__printf("test_map_lock:bpf_prog_load errno %d\n", errno);
 		goto close_prog;
 	}
 	map_fd[0] = bpf_find_map(__func__, obj, "hash_map");

tools/testing/selftests/bpf/prog_tests/send_signal.c

@@ -202,8 +202,8 @@ static int test_send_signal_nmi(void)
 			 -1 /* cpu */, -1 /* group_fd */, 0 /* flags */);
 	if (pmu_fd == -1) {
 		if (errno == ENOENT) {
-			printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n",
-				__func__);
+			test__printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n",
+				     __func__);
 			return 0;
 		}
 		/* Let the test fail with a more informative message */
@@ -222,8 +222,4 @@ void test_send_signal(void)
 	ret |= test_send_signal_tracepoint();
 	ret |= test_send_signal_perf();
 	ret |= test_send_signal_nmi();
-	if (!ret)
-		printf("test_send_signal:OK\n");
-	else
-		printf("test_send_signal:FAIL\n");
 }

tools/testing/selftests/bpf/prog_tests/spinlock.c

@@ -12,7 +12,7 @@ void test_spinlock(void)
 
 	err = bpf_prog_load(file, BPF_PROG_TYPE_CGROUP_SKB, &obj, &prog_fd);
 	if (err) {
-		printf("test_spin_lock:bpf_prog_load errno %d\n", errno);
+		test__printf("test_spin_lock:bpf_prog_load errno %d\n", errno);
 		goto close_prog;
 	}
 	for (i = 0; i < 4; i++)

tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c

@@ -109,8 +109,8 @@ void test_stacktrace_build_id(void)
 	if (build_id_matches < 1 && retry--) {
 		bpf_link__destroy(link);
 		bpf_object__close(obj);
-		printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
-		       __func__);
+		test__printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
+			     __func__);
 		goto retry;
 	}
 

tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c

@@ -140,8 +140,8 @@ void test_stacktrace_build_id_nmi(void)
 	if (build_id_matches < 1 && retry--) {
 		bpf_link__destroy(link);
 		bpf_object__close(obj);
-		printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
-		       __func__);
+		test__printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
+			     __func__);
 		goto retry;
 	}
 

tools/testing/selftests/bpf/prog_tests/xdp_noinline.c

@@ -75,7 +75,8 @@ void test_xdp_noinline(void)
 	}
 	if (bytes != MAGIC_BYTES * NUM_ITER * 2 || pkts != NUM_ITER * 2) {
 		error_cnt++;
-		printf("test_xdp_noinline:FAIL:stats %lld %lld\n", bytes, pkts);
+		test__printf("test_xdp_noinline:FAIL:stats %lld %lld\n",
+			     bytes, pkts);
 	}
 out:
 	bpf_object__close(obj);