Re: [RFC PATCH bpf-next 2/2] selftests/bpf: Add bpf link iter test

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Fri, Apr 22, 2022 at 11:23 AM Dmitrii Dolgov <9erthalion6@gmail.com> wrote:
>
> Add a simple test for bpf link iterator
>
> Signed-off-by: Dmitrii Dolgov <9erthalion6@gmail.com>
> ---
>  .../selftests/bpf/prog_tests/bpf_iter.c        | 15 +++++++++++++++
>  .../selftests/bpf/progs/bpf_iter_bpf_link.c    | 18 ++++++++++++++++++
>  2 files changed, 33 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_bpf_link.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> index 2c403ddc8076..e14a7a6d925c 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> @@ -26,6 +26,7 @@
>  #include "bpf_iter_bpf_sk_storage_map.skel.h"
>  #include "bpf_iter_test_kern5.skel.h"
>  #include "bpf_iter_test_kern6.skel.h"
> +#include "bpf_iter_bpf_link.skel.h"
>
>  static int duration;
>
> @@ -1172,6 +1173,20 @@ static void test_buf_neg_offset(void)
>                 bpf_iter_test_kern6__destroy(skel);
>  }
>
> +static void test_link_iter(void)
> +{
> +       struct bpf_iter_bpf_link *skel;
> +
> +       skel = bpf_iter_bpf_link__open_and_load();
> +       if (CHECK(skel, "bpf_iter_bpf_link__open_and_load",
> +                 "skeleton open_and_load unexpected success\n"))
> +               return;
> +

please don't use CHECK() for new tests, you need ASSERT_OK_PTR() here

> +       do_dummy_read(skel->progs.dump_bpf_link);
> +
> +       bpf_iter_bpf_link__destroy(skel);
> +}
> +
>  #define CMP_BUFFER_SIZE 1024
>  static char task_vma_output[CMP_BUFFER_SIZE];
>  static char proc_maps_output[CMP_BUFFER_SIZE];
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_link.c b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_link.c
> new file mode 100644
> index 000000000000..a5041fa1cda9
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_link.c
> @@ -0,0 +1,18 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2020 Facebook */
> +#include "bpf_iter.h"
> +#include <bpf/bpf_helpers.h>
> +
> +char _license[] SEC("license") = "GPL";
> +
> +SEC("iter/bpf_link")
> +int dump_bpf_link(struct bpf_iter__bpf_link *ctx)

see progs/bpf_iter.h, let's add bpf_iter__bpf_link there as well

> +{
> +       struct seq_file *seq = ctx->meta->seq;
> +       struct bpf_link *link = ctx->link;
> +       int link_id;
> +
> +       link_id = link->id;
> +       bpf_seq_write(seq, &link_id, sizeof(link_id));
> +       return 0;
> +}
> --
> 2.32.0
>