[PATCH bpf-next 1/2] selftests/bpf: test_progs: fix verbose mode garbage

[PATCH bpf-next 1/2] selftests/bpf: test_progs: fix verbose mode garbage

[Stanislav Fomichev]

fseeko(.., 0, SEEK_SET) on a memstream just puts the buffer pointer
to the beginning so when we call fflush on it we get some garbage
log data from the previous test. Let's manually set terminating
byte to zero at the reported buffer size.

To show the issue consider the following snippet:

	stream = open_memstream (&buf, &len);

	fprintf(stream, "aaa");
	fflush(stream);
	printf("buf=%s, len=%zu\n", buf, len);
	fseeko(stream, 0, SEEK_SET);

	fprintf(stream, "b");
	fflush(stream);
	printf("buf=%s, len=%zu\n", buf, len);

Output:

	buf=aaa, len=3
	buf=baa, len=1

Fixes: 946152b3c5d6 ("selftests/bpf: test_progs: switch to open_memstream")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/testing/selftests/bpf/test_progs.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index e5892cb60eca..e8616e778cb5 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -45,6 +45,7 @@ static void dump_test_log(const struct prog_test_def *test, bool failed)
 
 	if (env.verbose || test->force_log || failed) {
 		if (env.log_cnt) {
+			env.log_buf[env.log_cnt] = '\0';
 			fprintf(env.stdout, "%s", env.log_buf);
 			if (env.log_buf[env.log_cnt - 1] != '\n')
 				fprintf(env.stdout, "\n");
-- 
2.23.0.187.g17f5b7556c-goog

[PATCH bpf-next 2/2] selftests/bpf: test_progs: add missing \n to CHECK_FAIL

[Stanislav Fomichev]

Copy-paste error from CHECK.

Fixes: d38835b75f67 ("selftests/bpf: test_progs: remove global fail/success counts")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/testing/selftests/bpf/test_progs.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h
index 33da849cb765..c8edb9464ba6 100644
--- a/tools/testing/selftests/bpf/test_progs.h
+++ b/tools/testing/selftests/bpf/test_progs.h
@@ -107,7 +107,7 @@ extern struct ipv6_packet pkt_v6;
 	int __ret = !!(condition);					\
 	if (__ret) {							\
 		test__fail();						\
-		printf("%s:FAIL:%d ", __func__, __LINE__);		\
+		printf("%s:FAIL:%d\n", __func__, __LINE__);		\
 	}								\
 	__ret;								\
 })
-- 
2.23.0.187.g17f5b7556c-goog

Re: [PATCH bpf-next 1/2] selftests/bpf: test_progs: fix verbose mode garbage

[Daniel Borkmann]

On 8/31/19 4:34 AM, Stanislav Fomichev wrote:
> fseeko(.., 0, SEEK_SET) on a memstream just puts the buffer pointer
> to the beginning so when we call fflush on it we get some garbage
> log data from the previous test. Let's manually set terminating
> byte to zero at the reported buffer size.
> 
> To show the issue consider the following snippet:
> 
> 	stream = open_memstream (&buf, &len);
> 
> 	fprintf(stream, "aaa");
> 	fflush(stream);
> 	printf("buf=%s, len=%zu\n", buf, len);
> 	fseeko(stream, 0, SEEK_SET);
> 
> 	fprintf(stream, "b");
> 	fflush(stream);
> 	printf("buf=%s, len=%zu\n", buf, len);
> 
> Output:
> 
> 	buf=aaa, len=3
> 	buf=baa, len=1
> 
> Fixes: 946152b3c5d6 ("selftests/bpf: test_progs: switch to open_memstream")
> Signed-off-by: Stanislav Fomichev <sdf@google.com>

Both applied, thanks!