| Message ID | 20190831023427.239820-1-sdf@google.com |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [bpf-next,1/2] selftests/bpf: test_progs: fix verbose mode garbage | expand |
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!
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");
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(+)