On Sat, Mar 28, 2020 at 11:29 AM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote:
>
> This extends the global_data test to also exercise the new
> bpf_map__set_initial_value() function. The test simply overrides the global
> data section with all zeroes, and checks that the new value makes it into
> the kernel map on load.
>
> Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
> ---
> .../selftests/bpf/prog_tests/global_data.c | 61 +++++++++++++++++++
> 1 file changed, 61 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/global_data.c b/tools/testing/selftests/bpf/prog_tests/global_data.c
> index c680926fce73..f018ce53a8d1 100644
> --- a/tools/testing/selftests/bpf/prog_tests/global_data.c
> +++ b/tools/testing/selftests/bpf/prog_tests/global_data.c
> @@ -121,6 +121,65 @@ static void test_global_data_rdonly(struct bpf_object *obj, __u32 duration)
> "err %d errno %d\n", err, errno);
> }
>
> +static void test_global_data_set_rdonly(__u32 duration)
> +{
> + const char *file = "./test_global_data.o";
> + int err = -ENOMEM, map_fd, zero = 0;
> + __u8 *buff = NULL, *newval = NULL;
> + struct bpf_program *prog;
> + struct bpf_object *obj;
> + struct bpf_map *map;
> + size_t sz;
> +
> + obj = bpf_object__open_file(file, NULL);
Try using skeleton open and load .o file, it will cut this code almost in half.
> + if (CHECK_FAIL(!obj))
> + return;
> + prog = bpf_program__next(NULL, obj);
> + if (CHECK_FAIL(!prog))
> + goto out;
> + err = bpf_program__set_sched_cls(prog);
Please fix SEC() name for that program instead of setting type explicitly.
> + if (CHECK_FAIL(err))
> + goto out;
> +
> + map = bpf_object__find_map_by_name(obj, "test_glo.rodata");
> + if (CHECK_FAIL(!map || !bpf_map__is_internal(map)))
> + goto out;
> +
> + sz = bpf_map__def(map)->value_size;
> + newval = malloc(sz);
> + if (CHECK_FAIL(!newval))
> + goto out;
> + memset(newval, 0, sz);
> +
> + /* wrong size, should fail */
> + err = bpf_map__set_initial_value(map, newval, sz - 1);
> + if (CHECK(!err, "reject set initial value wrong size", "err %d\n", err))
> + goto out;
> +
> + err = bpf_map__set_initial_value(map, newval, sz);
> + if (CHECK_FAIL(err))
> + goto out;
> +
> + err = bpf_object__load(obj);
> + if (CHECK_FAIL(err))
> + goto out;
> +
> + map_fd = bpf_map__fd(map);
> + if (CHECK_FAIL(map_fd < 0))
> + goto out;
> +
> + buff = malloc(sz);
> + if (buff)
> + err = bpf_map_lookup_elem(map_fd, &zero, buff);
> + CHECK(!buff || err || memcmp(buff, newval, sz),
> + "compare .rodata map data override",
> + "err %d errno %d\n", err, errno);
> +out:
> + free(buff);
> + free(newval);
> + bpf_object__close(obj);
> +}
> +
> void test_global_data(void)
> {
> const char *file = "./test_global_data.o";
> @@ -144,4 +203,6 @@ void test_global_data(void)
> test_global_data_rdonly(obj, duration);
>
> bpf_object__close(obj);
> +
> + test_global_data_set_rdonly(duration);
This should either be a sub-test or better yet a separate test altogether.
> }
> --
> 2.26.0
>
